NAME

guestfs - Library for accessing and modifying virtual machine images

SYNOPSIS

 #include <guestfs.h>
 
 guestfs_h *g = guestfs_create ();
 guestfs_add_drive (g, "guest.img");
 guestfs_launch (g);
 guestfs_mount (g, "/dev/sda1", "/");
 guestfs_touch (g, "/hello");
 guestfs_umount (g, "/");
 guestfs_shutdown (g);
 guestfs_close (g);

 cc prog.c -o prog -lguestfs
or:
 cc prog.c -o prog `pkg-config libguestfs --cflags --libs`

DESCRIPTION

Libguestfs is a library for accessing and modifying disk images and virtual machines. This manual page documents the C API.

If you are looking for an introduction to libguestfs, see the web site: http://libguestfs.org/

Each virt tool has its own man page (for a full list, go to "SEE ALSO" at the end of this file).

The libguestfs FAQ contains many useful answers: guestfs-faq(1).

For examples of using the API from C, see guestfs-examples(3). For examples in other languages, see "USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES" below.

For tips and recipes, see guestfs-recipes(1).

If you are having performance problems, read guestfs-performance(1). To help test libguestfs, read libguestfs-test-tool(1) and guestfs-testing(1).

API OVERVIEW

This section provides a gentler overview of the libguestfs API. We also try to group API calls together, where that may not be obvious from reading about the individual calls in the main section of this manual.

HANDLES

Before you can use libguestfs calls, you have to create a handle. Then you must add at least one disk image to the handle, followed by launching the handle, then performing whatever operations you want, and finally closing the handle. By convention we use the single letter g for the name of the handle variable, although of course you can use any name you want.

The general structure of all libguestfs-using programs looks like this:

 guestfs_h *g = guestfs_create ();
 
 /* Call guestfs_add_drive additional times if there are
  * multiple disk images.
  */
 guestfs_add_drive (g, "guest.img");
 
 /* Most manipulation calls won't work until you've launched
  * the handle 'g'.  You have to do this _after_ adding drives
  * and _before_ other commands.
  */
 guestfs_launch (g);
 
 /* Either: examine what partitions, LVs etc are available: */
 char **partitions = guestfs_list_partitions (g);
 char **logvols = guestfs_lvs (g);
 
 /* Or: ask libguestfs to find filesystems for you: */
 char **filesystems = guestfs_list_filesystems (g);
 
 /* Or: use inspection (see INSPECTION section below). */
 
 /* To access a filesystem in the image, you must mount it. */
 guestfs_mount (g, "/dev/sda1", "/");
 
 /* Now you can perform filesystem actions on the guest
  * disk image.
  */
 guestfs_touch (g, "/hello");
 
 /* Synchronize the disk.  This is the opposite of guestfs_launch. */
 guestfs_shutdown (g);
 
 /* Close and free the handle 'g'. */
 guestfs_close (g);

The code above doesn't include any error checking. In real code you should check return values carefully for errors. In general all functions that return integers return -1 on error, and all functions that return pointers return NULL on error. See section "ERROR HANDLING" below for how to handle errors, and consult the documentation for each function call below to see precisely how they return error indications. See guestfs-examples(3) for fully worked examples.

DISK IMAGES

The image filename ("guest.img" in the example above) could be a disk image from a virtual machine, a dd(1) copy of a physical hard disk, an actual block device, or simply an empty file of zeroes that you have created through posix_fallocate(3). Libguestfs lets you do useful things to all of these.

The call you should use in modern code for adding drives is "guestfs_add_drive_opts". To add a disk image, allowing writes, and specifying that the format is raw, do:

 guestfs_add_drive_opts (g, filename,
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         -1);

You can add a disk read-only using:

 guestfs_add_drive_opts (g, filename,
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
                         -1);

or by calling the older function "guestfs_add_drive_ro". If you use the readonly flag, libguestfs won't modify the file. (See also "DISK IMAGE FORMATS" below).

Be extremely cautious if the disk image is in use, eg. if it is being used by a virtual machine. Adding it read-write will almost certainly cause disk corruption, but adding it read-only is safe.

You should usually add at least one disk image, and you may add multiple disk images. If adding multiple disk images, they usually have to be "related", ie. from the same guest. In the API, the disk images are usually referred to as /dev/sda (for the first one you added), /dev/sdb (for the second one you added), etc.

Once "guestfs_launch" has been called you cannot add any more images. You can call "guestfs_list_devices" to get a list of the device names, in the order that you added them. See also "BLOCK DEVICE NAMING" below.

There are slightly different rules when hotplugging disks (in libguestfs ≥ 1.20). See "HOTPLUGGING" below.

MOUNTING

Before you can read or write files, create directories and so on in a disk image that contains filesystems, you have to mount those filesystems using "guestfs_mount" or "guestfs_mount_ro". If you already know that a disk image contains (for example) one partition with a filesystem on that partition, then you can mount it directly:

 guestfs_mount (g, "/dev/sda1", "/");

where /dev/sda1 means literally the first partition (1) of the first disk image that we added (/dev/sda). If the disk contains Linux LVM2 logical volumes you could refer to those instead (eg. /dev/VG/LV). Note that these are libguestfs virtual devices, and are nothing to do with host devices.

If you are given a disk image and you don't know what it contains then you have to find out. Libguestfs can do that too: use "guestfs_list_partitions" and "guestfs_lvs" to list possible partitions and LVs, and either try mounting each to see what is mountable, or else examine them with "guestfs_vfs_type" or "guestfs_file". To list just filesystems, use "guestfs_list_filesystems".

Libguestfs also has a set of APIs for inspection of unknown disk images (see "INSPECTION" below). You might also want to look at higher level programs built on top of libguestfs, in particular virt-inspector(1).

To mount a filesystem read-only, use "guestfs_mount_ro". There are several other variations of the guestfs_mount_* call.

FILESYSTEM ACCESS AND MODIFICATION

The majority of the libguestfs API consists of fairly low-level calls for accessing and modifying the files, directories, symlinks etc on mounted filesystems. There are over a hundred such calls which you can find listed in detail below in this man page, and we don't even pretend to cover them all in this overview.

Specify filenames as full paths, starting with "/" and including the mount point.

For example, if you mounted a filesystem at "/" and you want to read the file called "etc/passwd" then you could do:

 char *data = guestfs_cat (g, "/etc/passwd");

This would return data as a newly allocated buffer containing the full content of that file (with some conditions: see also "DOWNLOADING" below), or NULL if there was an error.

As another example, to create a top-level directory on that filesystem called "var" you would do:

 guestfs_mkdir (g, "/var");

To create a symlink you could do:

 guestfs_ln_s (g, "/etc/init.d/portmap",
               "/etc/rc3.d/S30portmap");

Libguestfs will reject attempts to use relative paths and there is no concept of a current working directory.

Libguestfs can return errors in many situations: for example if the filesystem isn't writable, or if a file or directory that you requested doesn't exist. If you are using the C API (documented here) you have to check for those error conditions after each call. (Other language bindings turn these errors into exceptions).

File writes are affected by the per-handle umask, set by calling "guestfs_umask" and defaulting to 022. See "UMASK".

Since libguestfs 1.18, it is possible to mount the libguestfs filesystem on a local directory, subject to some restrictions. See "MOUNT LOCAL" below.

PARTITIONING

Libguestfs contains API calls to read, create and modify partition tables on disk images.

In the common case where you want to create a single partition covering the whole disk, you should use the "guestfs_part_disk" call:

 const char *parttype = "mbr";
 if (disk_is_larger_than_2TB)
   parttype = "gpt";
 guestfs_part_disk (g, "/dev/sda", parttype);

Obviously this effectively wipes anything that was on that disk image before.

LVM2

Libguestfs provides access to a large part of the LVM2 API, such as "guestfs_lvcreate" and "guestfs_vgremove". It won't make much sense unless you familiarize yourself with the concepts of physical volumes, volume groups and logical volumes.

This author strongly recommends reading the LVM HOWTO, online at http://tldp.org/HOWTO/LVM-HOWTO/.

DOWNLOADING

Use "guestfs_cat" to download small, text only files. This call cannot handle files containing any ASCII NUL (\0) characters. However the API is very simple to use.

"guestfs_read_file" can be used to read files which contain arbitrary 8 bit data, since it returns a (pointer, size) pair.

"guestfs_download" can be used to download any file, with no limits on content or size.

To download multiple files, see "guestfs_tar_out" and "guestfs_tgz_out".

UPLOADING

To write a small file with fixed content, use "guestfs_write". To create a file of all zeroes, use "guestfs_truncate_size" (sparse) or "guestfs_fallocate64" (with all disk blocks allocated). There are a variety of other functions for creating test files, for example "guestfs_fill" and "guestfs_fill_pattern".

To upload a single file, use "guestfs_upload". This call has no limits on file content or size.

To upload multiple files, see "guestfs_tar_in" and "guestfs_tgz_in".

However the fastest way to upload large numbers of arbitrary files is to turn them into a squashfs or CD ISO (see mksquashfs(8) and mkisofs(8)), then attach this using "guestfs_add_drive_ro". If you add the drive in a predictable way (eg. adding it last after all other drives) then you can get the device name from "guestfs_list_devices" and mount it directly using "guestfs_mount_ro". Note that squashfs images are sometimes non-portable between kernel versions, and they don't support labels or UUIDs. If you want to pre-build an image or you need to mount it using a label or UUID, use an ISO image instead.

COPYING

There are various different commands for copying between files and devices and in and out of the guest filesystem. These are summarised in the table below.

file to file

Use "guestfs_cp" to copy a single file, or "guestfs_cp_a" to copy directories recursively.

To copy part of a file (offset and size) use "guestfs_copy_file_to_file".

file to device
device to file
device to device

Use "guestfs_copy_file_to_device", "guestfs_copy_device_to_file", or "guestfs_copy_device_to_device".

Example: duplicate the contents of an LV:

 guestfs_copy_device_to_device (g,
         "/dev/VG/Original", "/dev/VG/Copy",
         /* -1 marks the end of the list of optional parameters */
         -1);

The destination (/dev/VG/Copy) must be at least as large as the source (/dev/VG/Original). To copy less than the whole source device, use the optional size parameter:

 guestfs_copy_device_to_device (g,
         "/dev/VG/Original", "/dev/VG/Copy",
         GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, 10000,
         -1);
file on the host to file or device

Use "guestfs_upload". See "UPLOADING" above.

file or device to file on the host

Use "guestfs_download". See "DOWNLOADING" above.

UPLOADING AND DOWNLOADING TO PIPES AND FILE DESCRIPTORS

Calls like "guestfs_upload", "guestfs_download", "guestfs_tar_in", "guestfs_tar_out" etc appear to only take filenames as arguments, so it appears you can only upload and download to files. However many Un*x-like hosts let you use the special device files /dev/stdin, /dev/stdout, /dev/stderr and /dev/fd/N to read and write from stdin, stdout, stderr, and arbitrary file descriptor N.

For example, virt-cat(1) writes its output to stdout by doing:

 guestfs_download (g, filename, "/dev/stdout");

and you can write tar output to a file descriptor fd by doing:

 char devfd[64];
 snprintf (devfd, sizeof devfd, "/dev/fd/%d", fd);
 guestfs_tar_out (g, "/", devfd);

LISTING FILES

"guestfs_ll" is just designed for humans to read (mainly when using the guestfish(1)-equivalent command ll).

"guestfs_ls" is a quick way to get a list of files in a directory from programs, as a flat list of strings.

"guestfs_readdir" is a programmatic way to get a list of files in a directory, plus additional information about each one. It is more equivalent to using the readdir(3) call on a local filesystem.

"guestfs_find" and "guestfs_find0" can be used to recursively list files.

RUNNING COMMANDS

Although libguestfs is primarily an API for manipulating files inside guest images, we also provide some limited facilities for running commands inside guests.

There are many limitations to this:

The two main API calls to run commands are "guestfs_command" and "guestfs_sh" (there are also variations).

The difference is that "guestfs_sh" runs commands using the shell, so any shell globs, redirections, etc will work.

CONFIGURATION FILES

To read and write configuration files in Linux guest filesystems, we strongly recommend using Augeas. For example, Augeas understands how to read and write, say, a Linux shadow password file or X.org configuration file, and so avoids you having to write that code.

The main Augeas calls are bound through the guestfs_aug_* APIs. We don't document Augeas itself here because there is excellent documentation on the http://augeas.net/ website.

If you don't want to use Augeas (you fool!) then try calling "guestfs_read_lines" to get the file as a list of lines which you can iterate over.

SYSTEMD JOURNAL FILES

To read the systemd journal from a Linux guest, use the guestfs_journal_* APIs starting with "guestfs_journal_open".

Consult the journal documentation here: sd-journal(3), sd_journal_open(3).

SELINUX

We support SELinux guests. To ensure that labeling happens correctly in SELinux guests, you need to enable SELinux and load the guest's policy:

  1. Before launching, do:

     guestfs_set_selinux (g, 1);
  2. After mounting the guest's filesystem(s), load the policy. This is best done by running the load_policy(8) command in the guest itself:

     guestfs_sh (g, "/usr/sbin/load_policy");

    (Older versions of load_policy require you to specify the name of the policy file).

  3. Optionally, set the security context for the API. The correct security context to use can only be known by inspecting the guest. As an example:

     guestfs_setcon (g, "unconfined_u:unconfined_r:unconfined_t:s0");

This will work for running commands and editing existing files.

When new files are created, you may need to label them explicitly, for example by running the external command restorecon pathname.

UMASK

Certain calls are affected by the current file mode creation mask (the "umask"). In particular ones which create files or directories, such as "guestfs_touch", "guestfs_mknod" or "guestfs_mkdir". This affects either the default mode that the file is created with or modifies the mode that you supply.

The default umask is 022, so files are created with modes such as 0644 and directories with 0755.

There are two ways to avoid being affected by umask. Either set umask to 0 (call guestfs_umask (g, 0) early after launching). Or call "guestfs_chmod" after creating each file or directory.

For more information about umask, see umask(2).

LABELS AND UUIDS

Many filesystems, devices and logical volumes support either labels (short strings like "BOOT" which might not be unique) and/or UUIDs (globally unique IDs).

For filesystems, use "guestfs_vfs_label" or "guestfs_vfs_uuid" to read the label or UUID. Some filesystems let you call "guestfs_set_label" or "guestfs_set_uuid" to change the label or UUID.

You can locate a filesystem by its label or UUID using "guestfs_findfs_label" or "guestfs_findfs_uuid".

For LVM2 (which supports only UUIDs), there is a rich set of APIs for fetching UUIDs, fetching UUIDs of the contained objects, and changing UUIDs. See: "guestfs_lvuuid", "guestfs_vguuid", "guestfs_pvuuid", "guestfs_vglvuuids", "guestfs_vgpvuuids", "guestfs_vgchange_uuid", "guestfs_vgchange_uuid_all", "guestfs_pvchange_uuid", "guestfs_pvchange_uuid_all".

Note when cloning a filesystem, device or whole guest, it is a good idea to set new randomly generated UUIDs on the copy.

ENCRYPTED DISKS

Libguestfs allows you to access Linux guests which have been encrypted using whole disk encryption that conforms to the Linux Unified Key Setup (LUKS) standard. This includes nearly all whole disk encryption systems used by modern Linux guests.

Use "guestfs_vfs_type" to identify LUKS-encrypted block devices (it returns the string crypto_LUKS).

Then open these devices by calling "guestfs_luks_open". Obviously you will require the passphrase!

Opening a LUKS device creates a new device mapper device called /dev/mapper/mapname (where mapname is the string you supply to "guestfs_luks_open"). Reads and writes to this mapper device are decrypted from and encrypted to the underlying block device respectively.

LVM volume groups on the device can be made visible by calling "guestfs_vgscan" followed by "guestfs_vg_activate_all". The logical volume(s) can now be mounted in the usual way.

Use the reverse process to close a LUKS device. Unmount any logical volumes on it, deactivate the volume groups by caling guestfs_vg_activate (g, 0, ["/dev/VG"]). Then close the mapper device by calling "guestfs_luks_close" on the /dev/mapper/mapname device (not the underlying encrypted block device).

MOUNT LOCAL

In libguestfs ≥ 1.18, it is possible to mount the libguestfs filesystem on a local directory and access it using ordinary POSIX calls and programs.

Availability of this is subject to a number of restrictions: it requires FUSE (the Filesystem in USErspace), and libfuse must also have been available when libguestfs was compiled. FUSE may require that a kernel module is loaded, and it may be necessary to add the current user to a special fuse group. See the documentation for your distribution and http://fuse.sf.net for further information.

The call to mount the libguestfs filesystem on a local directory is "guestfs_mount_local" (q.v.) followed by "guestfs_mount_local_run". The latter does not return until you unmount the filesystem. The reason is that the call enters the FUSE main loop and processes kernel requests, turning them into libguestfs calls. An alternative design would have been to create a background thread to do this, but libguestfs doesn't require pthreads. This way is also more flexible: for example the user can create another thread for "guestfs_mount_local_run".

"guestfs_mount_local" needs a certain amount of time to set up the mountpoint. The mountpoint is not ready to use until the call returns. At this point, accesses to the filesystem will block until the main loop is entered (ie. "guestfs_mount_local_run"). So if you need to start another process to access the filesystem, put the fork between "guestfs_mount_local" and "guestfs_mount_local_run".

MOUNT LOCAL COMPATIBILITY

Since local mounting was only added in libguestfs 1.18, and may not be available even in these builds, you should consider writing code so that it doesn't depend on this feature, and can fall back to using libguestfs file system calls.

If libguestfs was compiled without support for "guestfs_mount_local" then calling it will return an error with errno set to ENOTSUP (see "guestfs_last_errno").

MOUNT LOCAL PERFORMANCE

Libguestfs on top of FUSE performs quite poorly. For best performance do not use it. Use ordinary libguestfs filesystem calls, upload, download etc. instead.

HOTPLUGGING

In libguestfs ≥ 1.20, you may add drives and remove after calling "guestfs_launch". There are some restrictions, see below. This is called hotplugging.

Only a subset of the backends support hotplugging (currently only the libvirt backend has support). It also requires that you use libvirt ≥ 0.10.3 and qemu ≥ 1.2.

To hot-add a disk, simply call "guestfs_add_drive_opts" after "guestfs_launch". It is mandatory to specify the label parameter so that the newly added disk has a predictable name. For example:

 if (guestfs_launch (g) == -1)
   error ("launch failed");
 
 if (guestfs_add_drive_opts (g, filename,
                             GUESTFS_ADD_DRIVE_OPTS_LABEL, "newdisk",
                             -1) == -1)
   error ("hot-add of disk failed");
 
 if (guestfs_part_disk ("/dev/disk/guestfs/newdisk", "mbr") == -1)
   error ("partitioning of hot-added disk failed");

To hot-remove a disk, call "guestfs_remove_drive". You can call this before or after "guestfs_launch". You can only remove disks that were previously added with a label.

Backends that support hotplugging do not require that you add ≥ 1 disk before calling launch. When hotplugging is supported you don't need to add any disks.

REMOTE STORAGE

CEPH

Libguestfs can access Ceph (librbd/RBD) disks.

To do this, set the optional protocol and server parameters of "guestfs_add_drive_opts" like this:

 char **servers = { "ceph1.example.org:3000", /* ... */, NULL };
 guestfs_add_drive_opts (g, "pool/image",
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "rbd",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
                         GUESTFS_ADD_DRIVE_OPTS_USERNAME, "rbduser",
                         GUESTFS_ADD_DRIVE_OPTS_SECRET, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==",
                         -1);

servers (the server parameter) is a list of one or more Ceph servers. The server string is documented in "guestfs_add_drive_opts". The username and secret parameters are also optional, and if not given, then no authentication will be used.

FTP, HTTP AND TFTP

Libguestfs can access remote disks over FTP, FTPS, HTTP, HTTPS or TFTP protocols.

To do this, set the optional protocol and server parameters of "guestfs_add_drive_opts" like this:

 char **servers = { "www.example.org", NULL };
 guestfs_add_drive_opts (g, "/disk.img",
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "http",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
                         -1);

The protocol can be one of "ftp", "ftps", "http", "https" or "tftp".

servers (the server parameter) is a list which must have a single element. The single element is a string defining the web, FTP or TFTP server. The format of this string is documented in "guestfs_add_drive_opts".

GLUSTER

Libguestfs can access Gluster disks.

To do this, set the optional protocol and server parameters of "guestfs_add_drive_opts" like this:

 char **servers = { "gluster.example.org:24007", NULL };
 guestfs_add_drive_opts (g, "volname/image",
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "gluster",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
                         -1);

servers (the server parameter) is a list which must have a single element. The single element is a string defining the Gluster server. The format of this string is documented in "guestfs_add_drive_opts".

Note that gluster usually requires the client process (ie. libguestfs) to run as root and will give unfathomable errors if it is not (eg. "No data available").

ISCSI

Libguestfs can access iSCSI disks remotely.

To do this, set the optional protocol and server parameters like this:

 char **server = { "iscsi.example.org:3000", NULL };
 guestfs_add_drive_opts (g, "target-iqn-name/lun",
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "iscsi",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
                         -1);

The server parameter is a list which must have a single element. The single element is a string defining the iSCSI server. The format of this string is documented in "guestfs_add_drive_opts".

NETWORK BLOCK DEVICE

Libguestfs can access Network Block Device (NBD) disks remotely.

To do this, set the optional protocol and server parameters of "guestfs_add_drive_opts" like this:

 char **server = { "nbd.example.org:3000", NULL };
 guestfs_add_drive_opts (g, "" /* export name - see below */,
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "nbd",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
                         -1);

Notes:

SHEEPDOG

Libguestfs can access Sheepdog disks.

To do this, set the optional protocol and server parameters of "guestfs_add_drive_opts" like this:

 char **servers = { /* optional servers ... */ NULL };
 guestfs_add_drive_opts (g, "volume",
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "sheepdog",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
                         -1);

The optional list of servers may be zero or more server addresses ("hostname:port"). The format of the server strings is documented in "guestfs_add_drive_opts".

SSH

Libguestfs can access disks over a Secure Shell (SSH) connection.

To do this, set the protocol and server and (optionally) username parameters of "guestfs_add_drive_opts" like this:

 char **server = { "remote.example.com", NULL };
 guestfs_add_drive_opts (g, "/path/to/disk.img",
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                         GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "ssh",
                         GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
                         GUESTFS_ADD_DRIVE_OPTS_USERNAME, "remoteuser",
                         -1);

The format of the server string is documented in "guestfs_add_drive_opts".

INSPECTION

Libguestfs has APIs for inspecting an unknown disk image to find out if it contains operating systems, an install CD or a live CD.

Add all disks belonging to the unknown virtual machine and call "guestfs_launch" in the usual way.

Then call "guestfs_inspect_os". This function uses other libguestfs calls and certain heuristics, and returns a list of operating systems that were found. An empty list means none were found. A single element is the root filesystem of the operating system. For dual- or multi-boot guests, multiple roots can be returned, each one corresponding to a separate operating system. (Multi-boot virtual machines are extremely rare in the world of virtualization, but since this scenario can happen, we have built libguestfs to deal with it.)

For each root, you can then call various guestfs_inspect_get_* functions to get additional details about that operating system. For example, call "guestfs_inspect_get_type" to return the string windows or linux for Windows and Linux-based operating systems respectively.

Un*x-like and Linux-based operating systems usually consist of several filesystems which are mounted at boot time (for example, a separate boot partition mounted on /boot). The inspection rules are able to detect how filesystems correspond to mount points. Call guestfs_inspect_get_mountpoints to get this mapping. It might return a hash table like this example:

 /boot => /dev/sda1
 /     => /dev/vg_guest/lv_root
 /usr  => /dev/vg_guest/lv_usr

The caller can then make calls to "guestfs_mount" to mount the filesystems as suggested.

Be careful to mount filesystems in the right order (eg. / before /usr). Sorting the keys of the hash by length, shortest first, should work.

Inspection currently only works for some common operating systems. Contributors are welcome to send patches for other operating systems that we currently cannot detect.

Encrypted disks must be opened before inspection. See "ENCRYPTED DISKS" for more details. The "guestfs_inspect_os" function just ignores any encrypted devices.

A note on the implementation: The call "guestfs_inspect_os" performs inspection and caches the results in the guest handle. Subsequent calls to guestfs_inspect_get_* return this cached information, but do not re-read the disks. If you change the content of the guest disks, you can redo inspection by calling "guestfs_inspect_os" again. ("guestfs_inspect_list_applications2" works a little differently from the other calls and does read the disks. See documentation for that function for details).

INSPECTING INSTALL DISKS

Libguestfs (since 1.9.4) can detect some install disks, install CDs, live CDs and more.

Call "guestfs_inspect_get_format" to return the format of the operating system, which currently can be installed (a regular operating system) or installer (some sort of install disk).

Further information is available about the operating system that can be installed using the regular inspection APIs like "guestfs_inspect_get_product_name", "guestfs_inspect_get_major_version" etc.

Some additional information specific to installer disks is also available from the "guestfs_inspect_is_live", "guestfs_inspect_is_netinst" and "guestfs_inspect_is_multipart" calls.

SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS

Libguestfs can mount NTFS partitions. It does this using the http://www.ntfs-3g.org/ driver.

DRIVE LETTERS AND PATHS

DOS and Windows still use drive letters, and the filesystems are always treated as case insensitive by Windows itself, and therefore you might find a Windows configuration file referring to a path like c:\windows\system32. When the filesystem is mounted in libguestfs, that directory might be referred to as /WINDOWS/System32.

Drive letter mappings can be found using inspection (see "INSPECTION" and "guestfs_inspect_get_drive_mappings")

Dealing with separator characters (backslash vs forward slash) is outside the scope of libguestfs, but usually a simple character replacement will work.

To resolve the case insensitivity of paths, call "guestfs_case_sensitive_path".

LONG FILENAMES ON NTFS

NTFS supports filenames up to 255 characters long. "Character" means a 2 byte UTF-16 codepoint which can encode the most common Unicode codepoints.

Most Linux filesystems support filenames up to 255 bytes. This means you may get an error:

 File name too long

when you copy a file from NTFS to a Linux filesystem if the name, when reencoded as UTF-8, would exceed 255 bytes in length.

This will most often happen when using non-ASCII names that are longer than ~127 characters (eg. Greek, Cyrillic) or longer than ~85 characters (Asian languages).

A workaround is not to try to store such long filenames on Linux native filesystems. Since the tar(1) format can store unlimited length filenames, keep the files in a tarball.

ACCESSING THE WINDOWS REGISTRY

Libguestfs also provides some help for decoding Windows Registry "hive" files, through a separate C library called hivex(3).

Before libguestfs 1.19.35 you had to download the hive file, operate on it locally using hivex, and upload it again. Since this version, we have included the major hivex APIs directly in the libguestfs API (see "guestfs_hivex_open"). This means that if you have opened a Windows guest, you can read and write the registry directly.

See also virt-win-reg(1).

Ntfs-3g tries to rewrite "Junction Points" and NTFS "symbolic links" to provide something which looks like a Linux symlink. The way it tries to do the rewriting is described here:

http://www.tuxera.com/community/ntfs-3g-advanced/junction-points-and-symbolic-links/

The essential problem is that ntfs-3g simply does not have enough information to do a correct job. NTFS links can contain drive letters and references to external device GUIDs that ntfs-3g has no way of resolving. It is almost certainly the case that libguestfs callers should ignore what ntfs-3g does (ie. don't use "guestfs_readlink" on NTFS volumes).

Instead if you encounter a symbolic link on an ntfs-3g filesystem, use "guestfs_lgetxattr" to read the system.ntfs_reparse_data extended attribute, and read the raw reparse data from that (you can find the format documented in various places around the web).

EXTENDED ATTRIBUTES ON NTFS-3G FILESYSTEMS

There are other useful extended attributes that can be read from ntfs-3g filesystems (using "guestfs_getxattr"). See:

http://www.tuxera.com/community/ntfs-3g-advanced/extended-attributes/

WINDOWS HIBERNATION AND WINDOWS 8 FAST STARTUP

Windows guests which have been hibernated (instead of fully shut down) cannot be mounted. This is a limitation of ntfs-3g. You will see an error like this:

 The disk contains an unclean file system (0, 0).
 Metadata kept in Windows cache, refused to mount.
 Failed to mount '/dev/sda2': Operation not permitted
 The NTFS partition is in an unsafe state. Please resume
 and shutdown Windows fully (no hibernation or fast
 restarting), or mount the volume read-only with the
 'ro' mount option.

In Windows 8, the shutdown button does not shut down the guest at all. Instead it usually hibernates the guest. This is known as "fast startup".

Some suggested workarounds are:

RESIZE2FS ERRORS

The "guestfs_resize2fs", "guestfs_resize2fs_size" and "guestfs_resize2fs_M" calls are used to resize ext2/3/4 filesystems.

The underlying program (resize2fs(8)) requires that the filesystem is clean and recently fsck'd before you can resize it. Also, if the resize operation fails for some reason, then you had to call fsck the filesystem again to fix it.

In libguestfs lt 1.17.14, you usually had to call "guestfs_e2fsck_f" before the resize. However, in ge 1.17.14, e2fsck(8) is called automatically before the resize, so you no longer need to do this.

The resize2fs(8) program can still fail, in which case it prints an error message similar to:

 Please run 'e2fsck -fy <device>' to fix the filesystem
 after the aborted resize operation.

You can do this by calling "guestfs_e2fsck" with the forceall option. However in the context of disk images, it is usually better to avoid this situation, eg. by rolling back to an earlier snapshot, or by copying and resizing and on failure going back to the original.

USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES

Although we don't want to discourage you from using the C API, we will mention here that the same API is also available in other languages.

The API is broadly identical in all supported languages. This means that the C call guestfs_add_drive_ro(g,file) is $g->add_drive_ro($file) in Perl, g.add_drive_ro(file) in Python, and g#add_drive_ro file in OCaml. In other words, a straightforward, predictable isomorphism between each language.

Error messages are automatically transformed into exceptions if the language supports it.

We don't try to "object orientify" parts of the API in OO languages, although contributors are welcome to write higher level APIs above what we provide in their favourite languages if they wish.

C++

You can use the guestfs.h header file from C++ programs. The C++ API is identical to the C API. C++ classes and exceptions are not used.

C#

The C# bindings are highly experimental. Please read the warnings at the top of csharp/Libguestfs.cs.

Erlang

See guestfs-erlang(3).

GObject

Experimental GObject bindings (with GObject Introspection support) are available. See the gobject directory in the source.

Go

See <guestfs-golang(3)>.

Haskell

This language binding is working but incomplete:

Java

Full documentation is contained in the Javadoc which is distributed with libguestfs. For examples, see guestfs-java(3).

Lua

See guestfs-lua(3).

OCaml

See guestfs-ocaml(3).

Perl

See guestfs-perl(3) and Sys::Guestfs(3).

PHP

For documentation see README-PHP supplied with libguestfs sources or in the php-libguestfs package for your distribution.

The PHP binding only works correctly on 64 bit machines.

Python

See guestfs-python(3).

Ruby

See guestfs-ruby(3).

For JRuby, use the Java bindings.

shell scripts

See guestfish(1).

LIBGUESTFS GOTCHAS

http://en.wikipedia.org/wiki/Gotcha_(programming): "A feature of a system [...] that works in the way it is documented but is counterintuitive and almost invites mistakes."

Since we developed libguestfs and the associated tools, there are several things we would have designed differently, but are now stuck with for backwards compatibility or other reasons. If there is ever a libguestfs 2.0 release, you can expect these to change. Beware of them.

Read-only should be the default.

In guestfish(3), --ro should be the default, and you should have to specify --rw if you want to make changes to the image.

This would reduce the potential to corrupt live VM images.

Note that many filesystems change the disk when you just mount and unmount, even if you didn't perform any writes. You need to use "guestfs_add_drive_ro" to guarantee that the disk is not changed.

guestfish command line is hard to use.

guestfish disk.img doesn't do what people expect (open disk.img for examination). It tries to run a guestfish command disk.img which doesn't exist, so it fails. In earlier versions of guestfish the error message was also unintuitive, but we have corrected this since. Like the Bourne shell, we should have used guestfish -c command to run commands.

guestfish megabyte modifiers don't work right on all commands

In recent guestfish you can use 1M to mean 1 megabyte (and similarly for other modifiers). What guestfish actually does is to multiply the number part by the modifier part and pass the result to the C API. However this doesn't work for a few APIs which aren't expecting bytes, but are already expecting some other unit (eg. megabytes).

The most common is "guestfs_lvcreate". The guestfish command:

 lvcreate LV VG 100M

does not do what you might expect. Instead because "guestfs_lvcreate" is already expecting megabytes, this tries to create a 100 terabyte (100 megabytes * megabytes) logical volume. The error message you get from this is also a little obscure.

This could be fixed in the generator by specially marking parameters and return values which take bytes or other units.

Ambiguity between devices and paths

There is a subtle ambiguity in the API between a device name (eg. /dev/sdb2) and a similar pathname. A file might just happen to be called sdb2 in the directory /dev (consider some non-Unix VM image).

In the current API we usually resolve this ambiguity by having two separate calls, for example "guestfs_checksum" and "guestfs_checksum_device". Some API calls are ambiguous and (incorrectly) resolve the problem by detecting if the path supplied begins with /dev/.

To avoid both the ambiguity and the need to duplicate some calls, we could make paths/devices into structured names. One way to do this would be to use a notation like grub (hd(0,0)), although nobody really likes this aspect of grub. Another way would be to use a structured type, equivalent to this OCaml type:

 type path = Path of string | Device of int | Partition of int * int

which would allow you to pass arguments like:

 Path "/foo/bar"
 Device 1            (* /dev/sdb, or perhaps /dev/sda *)
 Partition (1, 2)    (* /dev/sdb2 (or is it /dev/sda2 or /dev/sdb3?) *)
 Path "/dev/sdb2"    (* not a device *)

As you can see there are still problems to resolve even with this representation. Also consider how it might work in guestfish.

KEYS AND PASSPHRASES

Certain libguestfs calls take a parameter that contains sensitive key material, passed in as a C string.

In the future we would hope to change the libguestfs implementation so that keys are mlock(2)-ed into physical RAM, and thus can never end up in swap. However this is not done at the moment, because of the complexity of such an implementation.

Therefore you should be aware that any key parameter you pass to libguestfs might end up being written out to the swap partition. If this is a concern, scrub the swap partition or don't use libguestfs on encrypted devices.

MULTIPLE HANDLES AND MULTIPLE THREADS

All high-level libguestfs actions are synchronous. If you want to use libguestfs asynchronously then you must create a thread.

Only use the handle from a single thread. Either use the handle exclusively from one thread, or provide your own mutex so that two threads cannot issue calls on the same handle at the same time. Even apparently innocent functions like "guestfs_get_trace" are not safe to be called from multiple threads without a mutex.

See the graphical program guestfs-browser for one possible architecture for multithreaded programs using libvirt and libguestfs.

PATH

Libguestfs needs a supermin appliance, which it finds by looking along an internal path.

By default it looks for these in the directory $libdir/guestfs (eg. /usr/local/lib/guestfs or /usr/lib64/guestfs).

Use "guestfs_set_path" or set the environment variable "LIBGUESTFS_PATH" to change the directories that libguestfs will search in. The value is a colon-separated list of paths. The current directory is not searched unless the path contains an empty element or .. For example LIBGUESTFS_PATH=:/usr/lib/guestfs would search the current directory and then /usr/lib/guestfs.

QEMU WRAPPERS

If you want to compile your own qemu, run qemu from a non-standard location, or pass extra arguments to qemu, then you can write a shell-script wrapper around qemu.

There is one important rule to remember: you must exec qemu as the last command in the shell script (so that qemu replaces the shell and becomes the direct child of the libguestfs-using program). If you don't do this, then the qemu process won't be cleaned up correctly.

Here is an example of a wrapper, where I have built my own copy of qemu from source:

 #!/bin/sh -
 qemudir=/home/rjones/d/qemu
 exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios "$@"

Save this script as /tmp/qemu.wrapper (or wherever), chmod +x, and then use it by setting the LIBGUESTFS_HV environment variable. For example:

 LIBGUESTFS_HV=/tmp/qemu.wrapper guestfish

Note that libguestfs also calls qemu with the -help and -version options in order to determine features.

Wrappers can also be used to edit the options passed to qemu. In the following example, the -machine ... option (-machine and the following argument) are removed from the command line and replaced with -machine pc,accel=tcg. The while loop iterates over the options until it finds the right one to remove, putting the remaining options into the args array.

 #!/bin/bash -
 
 i=0
 while [ $# -gt 0 ]; do
     case "$1" in
     -machine)
         shift 2;;
     *)
         args[i]="$1"
         (( i++ ))
         shift ;;
     esac
 done
 
 exec qemu-kvm -machine pc,accel=tcg "${args[@]}"

BACKEND

The backend (previously known as the "attach method") controls how libguestfs creates and/or connects to the backend daemon, eg. by starting qemu directly, or using libvirt to manage an appliance, running User-Mode Linux, or connecting to an already running daemon.

You can set the backend by calling "guestfs_set_backend", or by setting the environment variable LIBGUESTFS_BACKEND.

Possible backends are described below:

direct
appliance

Run qemu directly to launch an appliance.

direct and appliance are synonyms.

This is the ordinary method and normally the default, but see the note below.

libvirt
libvirt:null
libvirt:URI

Use libvirt to launch and manage the appliance.

libvirt causes libguestfs to choose a suitable URI for creating session guests. If using the libvirt backend, you almost always should use this.

libvirt:null causes libguestfs to use the NULL connection URI, which causes libvirt to try to guess what the user meant. You probably don't want to use this.

libvirt:URI uses URI as the libvirt connection URI (see http://libvirt.org/uri.html). The typical libvirt backend with a URI would be libvirt:qemu:///session

The libvirt backend supports more features, including hotplugging (see "HOTPLUGGING") and sVirt.

uml

Run the User-Mode Linux kernel. The location of the kernel is set using $LIBGUESTFS_HV or using the "guestfs_set_qemu" API (note that qemu is not involved, we just reuse the same variable in the handle for convenience).

User-Mode Linux can be much faster, simpler and more lightweight than using a full-blown virtual machine, but it also has some shortcomings. See "USER-MODE LINUX BACKEND" below.

unix:path

Connect to the Unix domain socket path.

This method lets you connect to an existing daemon or (using virtio-serial) to a live guest. For more information, see "ATTACHING TO RUNNING DAEMONS".

direct is usually the default backend. However since libguestfs ≥ 1.19.24, libguestfs can be built with a different default by doing:

 ./configure --with-default-backend=...

To find out if libguestfs was compiled with a different default backend, do:

 unset LIBGUESTFS_BACKEND
 guestfish get-backend

BACKEND SETTINGS

Each backend can be configured by passing a list of strings. You can either call "guestfs_set_backend_settings" with a list of strings, or set the LIBGUESTFS_BACKEND_SETTINGS environment variable to a colon-separated list of strings (before creating the handle).

Currently the only backend setting is:

 export LIBGUESTFS_BACKEND_SETTINGS=force_tcg

which will force the direct and libvirt backends to use TCG (software emulation) instead of KVM (hardware accelerated virtualization).

ATTACHING TO RUNNING DAEMONS

Note (1): This is highly experimental and has a tendency to eat babies. Use with caution.

Note (2): This section explains how to attach to a running daemon from a low level perspective. For most users, simply using virt tools such as guestfish(1) with the --live option will "just work".

Using guestfs_set_backend

By calling "guestfs_set_backend" you can change how the library connects to the guestfsd daemon in "guestfs_launch" (read "ARCHITECTURE" for some background).

The normal backend is direct, where a small appliance is created containing the daemon, and then the library connects to this. libvirt or libvirt:URI are alternatives that use libvirt to start the appliance.

Setting the backend to unix:path (where path is the path of a Unix domain socket) causes "guestfs_launch" to connect to an existing daemon over the Unix domain socket.

The normal use for this is to connect to a running virtual machine that contains a guestfsd daemon, and send commands so you can read and write files inside the live virtual machine.

Using guestfs_add_domain with live flag

"guestfs_add_domain" provides some help for getting the correct backend. If you pass the live option to this function, then (if the virtual machine is running) it will examine the libvirt XML looking for a virtio-serial channel to connect to:

 <domain>
   ...
   <devices>
     ...
     <channel type='unix'>
       <source mode='bind' path='/path/to/socket'/>
       <target type='virtio' name='org.libguestfs.channel.0'/>
     </channel>
     ...
   </devices>
 </domain>

"guestfs_add_domain" extracts /path/to/socket and sets the backend to unix:/path/to/socket.

Some of the libguestfs tools (including guestfish) support a --live option which is passed through to "guestfs_add_domain" thus allowing you to attach to and modify live virtual machines.

The virtual machine needs to have been set up beforehand so that it has the virtio-serial channel and so that guestfsd is running inside it.

USER-MODE LINUX BACKEND

Setting the following environment variables (or the equivalent in the API) selects the User-Mode Linux backend:

 export LIBGUESTFS_BACKEND=uml
 export LIBGUESTFS_HV=/path/to/vmlinux

vmlinux (or it may be called linux) is the Linux binary, compiled to run as a userspace process. Note that we reuse the qemu variable in the handle for convenience; qemu is not involved.

User-Mode Linux can be faster and more lightweight than running a full-blown virtual machine as the backend (especially if you are already running libguestfs in a virtual machine or cloud instance), but it also has some shortcomings compared to the usual qemu/KVM-based backend.

BUILDING USER-MODE LINUX FROM SOURCE

Your Linux distro may provide UML in which case you can ignore this section.

These instructions are adapted from: http://user-mode-linux.sourceforge.net/source.html

1. Check out Linux sources

Clone the Linux git repository or download the Linux source tarball.

2. Configure the kernel

Note: All 'make' commands must have ARCH=um added.

 make menuconfig ARCH=um

Make sure any filesystem drivers that you need are compiled into the kernel.

Currently, it needs a large amount of extra work to get modules working. It's recommended that you disable module support in the kernel configuration, which will cause everything to be compiled into the image.

3. Build the kernel
 make ARCH=um

This will leave a file called linux or vmlinux in the top-level directory. This is the UML kernel. You should set LIBGUESTFS_HV to point to this file.

USER-MODE LINUX DIFFERENCES FROM KVM

UML only supports raw-format images

Only plain raw-format images will work. No qcow2, no backing files.

UML does not support any remote drives

No NBD, etc.

UML only works on ix86 and x86-64
UML is experimental

In particular, support for UML in libguestfs depends on support for UML in the upstream kernel. If UML was ever removed from the upstream Linux kernel, then we might remove it from libguestfs too.

ABI GUARANTEE

We guarantee the libguestfs ABI (binary interface), for public, high-level actions as outlined in this section. Although we will deprecate some actions, for example if they get replaced by newer calls, we will keep the old actions forever. This allows you the developer to program in confidence against the libguestfs API.

BLOCK DEVICE NAMING

In the kernel there is now quite a profusion of schemata for naming block devices (in this context, by block device I mean a physical or virtual hard drive). The original Linux IDE driver used names starting with /dev/hd*. SCSI devices have historically used a different naming scheme, /dev/sd*. When the Linux kernel libata driver became a popular replacement for the old IDE driver (particularly for SATA devices) those devices also used the /dev/sd* scheme. Additionally we now have virtual machines with paravirtualized drivers. This has created several different naming systems, such as /dev/vd* for virtio disks and /dev/xvd* for Xen PV disks.

As discussed above, libguestfs uses a qemu appliance running an embedded Linux kernel to access block devices. We can run a variety of appliances based on a variety of Linux kernels.

This causes a problem for libguestfs because many API calls use device or partition names. Working scripts and the recipe (example) scripts that we make available over the internet could fail if the naming scheme changes.

Therefore libguestfs defines /dev/sd* as the standard naming scheme. Internally /dev/sd* names are translated, if necessary, to other names as required. For example, under RHEL 5 which uses the /dev/hd* scheme, any device parameter /dev/sda2 is translated to /dev/hda2 transparently.

Note that this only applies to parameters. The "guestfs_list_devices", "guestfs_list_partitions" and similar calls return the true names of the devices and partitions as known to the appliance, but see "guestfs_canonical_device_name".

DISK LABELS

In libguestfs ≥ 1.20, you can give a label to a disk when you add it, using the optional label parameter to "guestfs_add_drive_opts". (Note that disk labels are different from and not related to filesystem labels).

Not all versions of libguestfs support setting a disk label, and when it is supported, it is limited to 20 ASCII characters [a-zA-Z].

When you add a disk with a label, it can either be addressed using /dev/sd*, or using /dev/disk/guestfs/label. Partitions on the disk can be addressed using /dev/disk/guestfs/labelpartnum.

Listing devices ("guestfs_list_devices") and partitions ("guestfs_list_partitions") returns the raw block device name. However you can use "guestfs_list_disk_labels" to map disk labels to raw block device and partition names.

ALGORITHM FOR BLOCK DEVICE NAME TRANSLATION

Usually this translation is transparent. However in some (very rare) cases you may need to know the exact algorithm. Such cases include where you use "guestfs_config" to add a mixture of virtio and IDE devices to the qemu-based appliance, so have a mixture of /dev/sd* and /dev/vd* devices.

The algorithm is applied only to parameters which are known to be either device or partition names. Return values from functions such as "guestfs_list_devices" are never changed.

PORTABILITY CONCERNS WITH BLOCK DEVICE NAMING

Although the standard naming scheme and automatic translation is useful for simple programs and guestfish scripts, for larger programs it is best not to rely on this mechanism.

Where possible for maximum future portability programs using libguestfs should use these future-proof techniques:

NULL DISKS

When adding a disk using, eg., "guestfs_add_drive", you can set the filename to "/dev/null". This string is treated specially by libguestfs, causing it to add a "null disk".

A null disk has the following properties:

Null disks are used for three main purposes:

  1. Performance testing of libguestfs (see guestfs-performance(1)).

  2. The internal test suite.

  3. If you want to use libguestfs APIs that don't refer to disks, since libguestfs requires that at least one disk is added, you should add a null disk.

    For example, to test if a feature is available, use code like this:

     guestfs_h *g;
     char **groups = [ "btrfs", NULL ];
     
     g = guestfs_create ();
     guestfs_add_drive (g, "/dev/null");
     guestfs_launch (g);
     if (guestfs_available (g, groups) == 0) {
       // group(s) are available
     } else {
       // group(s) are not available
     }
     guestfs_close (g);

DISK IMAGE FORMATS

Virtual disks come in a variety of formats. Some common formats are listed below.

Note that libguestfs itself is not responsible for handling the disk format: this is done using qemu(1). If support for a particular format is missing or broken, this has to be fixed in qemu.

COMMON VIRTUAL DISK IMAGE FORMATS

raw

Raw format is simply a dump of the sequential bytes of the virtual hard disk. There is no header, container, compression or processing of any sort.

Since raw format requires no translation to read or write, it is both fast and very well supported by qemu and all other hypervisors. You can consider it to be a universal format that any hypervisor can access.

Raw format files are not compressed and so take up the full space of the original disk image even when they are empty. A variation (on Linux/Unix at least) is to not store ranges of all-zero bytes by storing the file as a sparse file. This "variant format" is sometimes called raw sparse. Many utilities, including virt-sparsify(1), can make raw disk images sparse.

qcow2

Qcow2 is the native disk image format used by qemu. Internally it uses a two-level directory structure so that only blocks containing data are stored in the file. It also has many other features such as compression, snapshots and backing files.

There are at least two distinct variants of this format, although qemu (and hence libguestfs) handles both transparently to the user.

vmdk

VMDK is VMware's native disk image format. There are many variations. Modern qemu (hence libguestfs) supports most variations, but you should be aware that older versions of qemu had some very bad data-corrupting bugs in this area.

Note that VMware ESX exposes files with the name guest-flat.vmdk. These are not VMDK. They are raw format files which happen to have a .vmdk extension.

vdi

VDI is VirtualBox's native disk image format. Qemu (hence libguestfs) has generally good support for this.

vpc
vhd

VPC (old) and VHD (modern) are the native disk image format of Microsoft (and previously, Connectix) Virtual PC and Hyper-V.

Obsolete formats

The following formats are obsolete and should not be used: qcow (aka qcow1), cow, bochs.

DETECTING THE FORMAT OF A DISK IMAGE

Firstly note there is a security issue with auto-detecting the format of a disk image. It may or may not apply in your use case. Read "CVE-2010-3851" below.

Libguestfs offers an API to get the format of a disk image ("guestfs_disk_format", and it is safest to use this.

Don't be tempted to try parsing the text / human-readable output of qemu-img since it cannot be parsed reliably and securely. Also do not use the file command since the output of that changes over time.

SECURITY

This section discusses security implications of using libguestfs, particularly with untrusted or malicious guests or disk images.

SECURITY OF MOUNTING FILESYSTEMS

You should never mount an untrusted guest filesystem directly on your host kernel (eg. using loopback or kpartx).

When you mount a filesystem, mistakes in the kernel filesystem (VFS) can be escalated into exploits by attackers creating a malicious filesystem. These exploits are very severe for two reasons. Firstly there are very many filesystem drivers in the kernel, and many of them are infrequently used and not much developer attention has been paid to the code. Linux userspace helps potential crackers by detecting the filesystem type and automatically choosing the right VFS driver, even if that filesystem type is unexpected. Secondly, a kernel-level exploit is like a local root exploit (worse in some ways), giving immediate and total access to the system right down to the hardware level.

These exploits can be present in the kernel for a very long time (https://lwn.net/Articles/538898/).

Libguestfs provides a layered approach to protecting you from exploits:

   untrusted filesystem
 --------------------------------------
   appliance kernel
 --------------------------------------
   qemu process running as non-root
 --------------------------------------
   sVirt [if using libvirt + SELinux]
 --------------------------------------
   host kernel

We run a Linux kernel inside a qemu virtual machine, usually running as a non-root user. The attacker would need to write a filesystem which first exploited the kernel, and then exploited either qemu virtualization (eg. a faulty qemu driver) or the libguestfs protocol, and finally to be as serious as the host kernel exploit it would need to escalate its privileges to root. Additionally if you use the libvirt back end and SELinux, sVirt is used to confine the qemu process. This multi-step escalation, performed by a static piece of data, is thought to be extremely hard to do, although we never say 'never' about security issues.

Callers can also reduce the attack surface by forcing the filesystem type when mounting (use "guestfs_mount_vfs").

GENERAL SECURITY CONSIDERATIONS

Be careful with any files or data that you download from a guest (by "download" we mean not just the "guestfs_download" command but any command that reads files, filenames, directories or anything else from a disk image). An attacker could manipulate the data to fool your program into doing the wrong thing. Consider cases such as:

PROTOCOL SECURITY

The protocol is designed to be secure, being based on RFC 4506 (XDR) with a defined upper message size. However a program that uses libguestfs must also take care - for example you can write a program that downloads a binary from a disk image and executes it locally, and no amount of protocol security will save you from the consequences.

INSPECTION SECURITY

Parts of the inspection API (see "INSPECTION") return untrusted strings directly from the guest, and these could contain any 8 bit data. Callers should be careful to escape these before printing them to a structured file (for example, use HTML escaping if creating a web page).

Guest configuration may be altered in unusual ways by the administrator of the virtual machine, and may not reflect reality (particularly for untrusted or actively malicious guests). For example we parse the hostname from configuration files like /etc/sysconfig/network that we find in the guest, but the guest administrator can easily manipulate these files to provide the wrong hostname.

The inspection API parses guest configuration using two external libraries: Augeas (Linux configuration) and hivex (Windows Registry). Both are designed to be robust in the face of malicious data, although denial of service attacks are still possible, for example with oversized configuration files.

RUNNING UNTRUSTED GUEST COMMANDS

Be very cautious about running commands from the guest. By running a command in the guest, you are giving CPU time to a binary that you do not control, under the same user account as the library, albeit wrapped in qemu virtualization. More information and alternatives can be found in the section "RUNNING COMMANDS".

CVE-2010-3851

https://bugzilla.redhat.com/642934

This security bug concerns the automatic disk format detection that qemu does on disk images.

A raw disk image is just the raw bytes, there is no header. Other disk images like qcow2 contain a special header. Qemu deals with this by looking for one of the known headers, and if none is found then assuming the disk image must be raw.

This allows a guest which has been given a raw disk image to write some other header. At next boot (or when the disk image is accessed by libguestfs) qemu would do autodetection and think the disk image format was, say, qcow2 based on the header written by the guest.

This in itself would not be a problem, but qcow2 offers many features, one of which is to allow a disk image to refer to another image (called the "backing disk"). It does this by placing the path to the backing disk into the qcow2 header. This path is not validated and could point to any host file (eg. "/etc/passwd"). The backing disk is then exposed through "holes" in the qcow2 disk image, which of course is completely under the control of the attacker.

In libguestfs this is rather hard to exploit except under two circumstances:

  1. You have enabled the network or have opened the disk in write mode.

  2. You are also running untrusted code from the guest (see "RUNNING COMMANDS").

The way to avoid this is to specify the expected disk format when adding disks (the optional format option to "guestfs_add_drive_opts"). You should always do this if the disk is raw format, and it's a good idea for other cases too. (See also "DISK IMAGE FORMATS").

For disks added from libvirt using calls like "guestfs_add_domain", the format is fetched from libvirt and passed through.

For libguestfs tools, use the --format command line parameter as appropriate.

CVE-2011-4127

https://bugzilla.redhat.com/752375

This is a bug in the kernel which allowed guests to overwrite parts of the host's drives which they should not normally have access to.

It is sufficient to update libguestfs to any version ≥ 1.16 which contains a change that mitigates the problem.

CVE-2012-2690

https://bugzilla.redhat.com/831117

Old versions of both virt-edit and the guestfish edit command created a new file containing the changes but did not set the permissions, etc of the new file to match the old one. The result of this was that if you edited a security sensitive file such as /etc/shadow then it would be left world-readable after the edit.

It is sufficient to update libguestfs to any version ≥ 1.16.

CVE-2013-2124

https://bugzilla.redhat.com/968306

This security bug was a flaw in inspection where an untrusted guest using a specially crafted file in the guest OS could cause a double-free in the C library (denial of service).

It is sufficient to update libguestfs to a version that is not vulnerable: libguestfs ≥ 1.20.8, ≥ 1.22.2 or ≥ 1.23.2.

CVE-2013-4419

https://bugzilla.redhat.com/1016960

When using the guestfish(1) --remote or guestfish --listen options, guestfish would create a socket in a known location (/tmp/.guestfish-$UID/socket-$PID).

The location has to be a known one in order for both ends to communicate. However no checking was done that the containing directory (/tmp/.guestfish-$UID) is owned by the user. Thus another user could create this directory and potentially hijack sockets owned by another user's guestfish client or server.

It is sufficient to update libguestfs to a version that is not vulnerable: libguestfs ≥ 1.20.12, ≥ 1.22.7 or ≥ 1.24.

CONNECTION MANAGEMENT

guestfs_h *

guestfs_h is the opaque type representing a connection handle. Create a handle by calling "guestfs_create" or "guestfs_create_flags". Call "guestfs_close" to free the handle and release all resources used.

For information on using multiple handles and threads, see the section "MULTIPLE HANDLES AND MULTIPLE THREADS" above.

guestfs_create

 guestfs_h *guestfs_create (void);

Create a connection handle.

On success this returns a non-NULL pointer to a handle. On error it returns NULL.

You have to "configure" the handle after creating it. This includes calling "guestfs_add_drive_opts" (or one of the equivalent calls) on the handle at least once.

After configuring the handle, you have to call "guestfs_launch".

You may also want to configure error handling for the handle. See the "ERROR HANDLING" section below.

guestfs_create_flags

 guestfs_h *guestfs_create_flags (unsigned flags [, ...]);

Create a connection handle, supplying extra flags and extra arguments to control how the handle is created.

On success this returns a non-NULL pointer to a handle. On error it returns NULL.

"guestfs_create" is equivalent to calling guestfs_create_flags(0).

The following flags may be logically ORed together. (Currently no extra arguments are used).

GUESTFS_CREATE_NO_ENVIRONMENT

Don't parse any environment variables (such as LIBGUESTFS_DEBUG etc).

You can call "guestfs_parse_environment" or "guestfs_parse_environment_list" afterwards to parse environment variables. Alternately, don't call these functions if you want the handle to be unaffected by environment variables. See the example below.

The default (if this flag is not given) is to implicitly call "guestfs_parse_environment".

GUESTFS_CREATE_NO_CLOSE_ON_EXIT

Don't try to close the handle in an atexit(3) handler if the program exits without explicitly closing the handle.

The default (if this flag is not given) is to install such an atexit handler.

USING GUESTFS_CREATE_NO_ENVIRONMENT

You might use GUESTFS_CREATE_NO_ENVIRONMENT and an explicit call to "guestfs_parse_environment" like this:

 guestfs_h *g;
 int r;
 
 g = guestfs_create_flags (GUESTFS_CREATE_NO_ENVIRONMENT);
 if (!g) {
   perror ("guestfs_create_flags");
   exit (EXIT_FAILURE);
 }
 r = guestfs_parse_environment (g);
 if (r == -1)
   exit (EXIT_FAILURE);

Or to create a handle which is unaffected by environment variables, omit the call to guestfs_parse_environment from the above code.

The above code has another advantage which is that any errors from parsing the environment are passed through the error handler, whereas guestfs_create prints errors on stderr and ignores them.

guestfs_close

 void guestfs_close (guestfs_h *g);

This closes the connection handle and frees up all resources used. If a close callback was set on the handle, then it is called.

The correct way to close the handle is:

 if (guestfs_shutdown (g) == -1) {
   /* handle write errors here */
 }
 guestfs_close (g);

"guestfs_shutdown" is only needed if all of the following are true:

  1. one or more disks were added in read-write mode, and

  2. guestfs_launch was called, and

  3. you made some changes, and

  4. you have a way to handle write errors (eg. by exiting with an error code or reporting something to the user).

ERROR HANDLING

API functions can return errors. For example, almost all functions that return int will return -1 to indicate an error.

Additional information is available for errors: an error message string and optionally an error number (errno) if the thing that failed was a system call.

You can get at the additional information about the last error on the handle by calling "guestfs_last_error", "guestfs_last_errno", and/or by setting up an error handler with "guestfs_set_error_handler".

When the handle is created, a default error handler is installed which prints the error message string to stderr. For small short-running command line programs it is sufficient to do:

 if (guestfs_launch (g) == -1)
   exit (EXIT_FAILURE);

since the default error handler will ensure that an error message has been printed to stderr before the program exits.

For other programs the caller will almost certainly want to install an alternate error handler or do error handling in-line as in the example below. The non-C language bindings all install NULL error handlers and turn errors into exceptions using code similar to this:

 const char *msg;
 int errnum;
 
 /* This disables the default behaviour of printing errors
    on stderr. */
 guestfs_set_error_handler (g, NULL, NULL);
 
 if (guestfs_launch (g) == -1) {
   /* Examine the error message and print it, throw it,
      etc. */
   msg = guestfs_last_error (g);
   errnum = guestfs_last_errno (g);
 
   fprintf (stderr, "%s", msg);
   if (errnum != 0)
     fprintf (stderr, ": %s", strerror (errnum));
   fprintf (stderr, "\n");
 
   /* ... */
 }

"guestfs_create" returns NULL if the handle cannot be created, and because there is no handle if this happens there is no way to get additional error information. Since libguestfs ≥ 1.20, you can use "guestfs_create_flags" to properly deal with errors during handle creation, although the vast majority of programs can continue to use "guestfs_create" and not worry about this situation.

Out of memory errors are handled differently. The default action is to call abort(3). If this is undesirable, then you can set a handler using "guestfs_set_out_of_memory_handler".

guestfs_last_error

 const char *guestfs_last_error (guestfs_h *g);

This returns the last error message that happened on g. If there has not been an error since the handle was created, then this returns NULL.

Note the returned string does not have a newline character at the end. Most error messages are single lines. Some are split over multiple lines and contain \n characters within the string but not at the end.

The lifetime of the returned string is until the next error occurs on the same handle, or "guestfs_close" is called. If you need to keep it longer, copy it.

guestfs_last_errno

 int guestfs_last_errno (guestfs_h *g);

This returns the last error number (errno) that happened on g.

If successful, an errno integer not equal to zero is returned.

In many cases the special errno ENOTSUP is returned if you tried to call a function or use a feature which is not supported.

If no error number is available, this returns 0. This call can return 0 in three situations:

  1. There has not been any error on the handle.

  2. There has been an error but the errno was meaningless. This corresponds to the case where the error did not come from a failed system call, but for some other reason.

  3. There was an error from a failed system call, but for some reason the errno was not captured and returned. This usually indicates a bug in libguestfs.

Libguestfs tries to convert the errno from inside the applicance into a corresponding errno for the caller (not entirely trivial: the appliance might be running a completely different operating system from the library and error numbers are not standardized across Un*xen). If this could not be done, then the error is translated to EINVAL. In practice this should only happen in very rare circumstances.

guestfs_set_error_handler

 typedef void (*guestfs_error_handler_cb) (guestfs_h *g,
                                           void *opaque,
                                           const char *msg);
 void guestfs_set_error_handler (guestfs_h *g,
                                 guestfs_error_handler_cb cb,
                                 void *opaque);

The callback cb will be called if there is an error. The parameters passed to the callback are an opaque data pointer and the error message string.

errno is not passed to the callback. To get that the callback must call "guestfs_last_errno".

Note that the message string msg is freed as soon as the callback function returns, so if you want to stash it somewhere you must make your own copy.

The default handler prints messages on stderr.

If you set cb to NULL then no handler is called.

guestfs_get_error_handler

 guestfs_error_handler_cb guestfs_get_error_handler (guestfs_h *g,
                                                     void **opaque_rtn);

Returns the current error handler callback.

guestfs_push_error_handler

 void guestfs_push_error_handler (guestfs_h *g,
                                  guestfs_error_handler_cb cb,
                                  void *opaque);

This is the same as "guestfs_set_error_handler", except that the old error handler is stashed away in a stack inside the handle. You can restore the previous error handler by calling "guestfs_pop_error_handler".

Use the following code to temporarily disable errors around a function:

 guestfs_push_error_handler (g, NULL, NULL);
 guestfs_mkdir (g, "/foo"); /* We don't care if this fails. */
 guestfs_pop_error_handler (g);

guestfs_pop_error_handler

 void guestfs_pop_error_handler (guestfs_h *g);

Restore the previous error handler (see "guestfs_push_error_handler").

If you pop the stack too many times, then the default error handler is restored.

guestfs_set_out_of_memory_handler

 typedef void (*guestfs_abort_cb) (void);
 void guestfs_set_out_of_memory_handler (guestfs_h *g,
                                         guestfs_abort_cb);

The callback cb will be called if there is an out of memory situation. Note this callback must not return.

The default is to call abort(3).

You cannot set cb to NULL. You can't ignore out of memory situations.

guestfs_get_out_of_memory_handler

 guestfs_abort_fn guestfs_get_out_of_memory_handler (guestfs_h *g);

This returns the current out of memory handler.

API CALLS

guestfs_acl_delete_def_file

 int
 guestfs_acl_delete_def_file (guestfs_h *g,
                              const char *dir);

This function deletes the default POSIX Access Control List (ACL) attached to directory dir.

This function returns 0 on success or -1 on error.

(Added in 1.19.63)

guestfs_acl_get_file

 char *
 guestfs_acl_get_file (guestfs_h *g,
                       const char *path,
                       const char *acltype);

This function returns the POSIX Access Control List (ACL) attached to path. The ACL is returned in "long text form" (see acl(5)).

The acltype parameter may be:

access

Return the ordinary (access) ACL for any file, directory or other filesystem object.

default

Return the default ACL. Normally this only makes sense if path is a directory.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.63)

guestfs_acl_set_file

 int
 guestfs_acl_set_file (guestfs_h *g,
                       const char *path,
                       const char *acltype,
                       const char *acl);

This function sets the POSIX Access Control List (ACL) attached to path.

The acltype parameter may be:

access

Set the ordinary (access) ACL for any file, directory or other filesystem object.

default

Set the default ACL. Normally this only makes sense if path is a directory.

The acl parameter is the new ACL in either "long text form" or "short text form" (see acl(5)). The new ACL completely replaces any previous ACL on the file. The ACL must contain the full Unix permissions (eg. u::rwx,g::rx,o::rx).

If you are specifying individual users or groups, then the mask field is also required (eg. m::rwx), followed by the u:ID:... and/or g:ID:... field(s). A full ACL string might therefore look like this:

 u::rwx,g::rwx,o::rwx,m::rwx,u:500:rwx,g:500:rwx
 \ Unix permissions / \mask/ \      ACL        /

You should use numeric UIDs and GIDs. To map usernames and groupnames to the correct numeric ID in the context of the guest, use the Augeas functions (see guestfs_aug_init).

This function returns 0 on success or -1 on error.

(Added in 1.19.63)

guestfs_add_cdrom

 int
 guestfs_add_cdrom (guestfs_h *g,
                    const char *filename);

This function is deprecated. In new code, use the "guestfs_add_drive_ro" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This function adds a virtual CD-ROM disk image to the guest.

The image is added as read-only drive, so this function is equivalent of guestfs_add_drive_ro.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_add_domain

 int
 guestfs_add_domain (guestfs_h *g,
                     const char *dom,
                     ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_ADD_DOMAIN_LIBVIRTURI, const char *libvirturi,
 GUESTFS_ADD_DOMAIN_READONLY, int readonly,
 GUESTFS_ADD_DOMAIN_IFACE, const char *iface,
 GUESTFS_ADD_DOMAIN_LIVE, int live,
 GUESTFS_ADD_DOMAIN_ALLOWUUID, int allowuuid,
 GUESTFS_ADD_DOMAIN_READONLYDISK, const char *readonlydisk,
 GUESTFS_ADD_DOMAIN_CACHEMODE, const char *cachemode,
 GUESTFS_ADD_DOMAIN_DISCARD, const char *discard,

This function adds the disk(s) attached to the named libvirt domain dom. It works by connecting to libvirt, requesting the domain and domain XML from libvirt, parsing it for disks, and calling guestfs_add_drive_opts on each one.

The number of disks added is returned. This operation is atomic: if an error is returned, then no disks are added.

This function does some minimal checks to make sure the libvirt domain is not running (unless readonly is true). In a future version we will try to acquire the libvirt lock on each disk.

Disks must be accessible locally. This often means that adding disks from a remote libvirt connection (see http://libvirt.org/remote.html) will fail unless those disks are accessible via the same device path locally too.

The optional libvirturi parameter sets the libvirt URI (see http://libvirt.org/uri.html). If this is not set then we connect to the default libvirt URI (or one set through an environment variable, see the libvirt documentation for full details).

The optional live flag controls whether this call will try to connect to a running virtual machine guestfsd process if it sees a suitable <channel> element in the libvirt XML definition. The default (if the flag is omitted) is never to try. See "ATTACHING TO RUNNING DAEMONS" in guestfs(3) for more information.

If the allowuuid flag is true (default is false) then a UUID may be passed instead of the domain name. The dom string is treated as a UUID first and looked up, and if that lookup fails then we treat dom as a name as usual.

The optional readonlydisk parameter controls what we do for disks which are marked <readonly/> in the libvirt XML. Possible values are:

readonlydisk = "error"

If readonly is false:

The whole call is aborted with an error if any disk with the <readonly/> flag is found.

If readonly is true:

Disks with the <readonly/> flag are added read-only.

readonlydisk = "read"

If readonly is false:

Disks with the <readonly/> flag are added read-only. Other disks are added read/write.

If readonly is true:

Disks with the <readonly/> flag are added read-only.

readonlydisk = "write" (default)

If readonly is false:

Disks with the <readonly/> flag are added read/write.

If readonly is true:

Disks with the <readonly/> flag are added read-only.

readonlydisk = "ignore"

If readonly is true or false:

Disks with the <readonly/> flag are skipped.

The other optional parameters are passed directly through to guestfs_add_drive_opts.

On error this function returns -1.

(Added in 1.7.4)

guestfs_add_domain_va

 int
 guestfs_add_domain_va (guestfs_h *g,
                        const char *dom,
                        va_list args);

This is the "va_list variant" of "guestfs_add_domain".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_add_domain_argv

 int
 guestfs_add_domain_argv (guestfs_h *g,
                          const char *dom,
                          const struct guestfs_add_domain_argv *optargs);

This is the "argv variant" of "guestfs_add_domain".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_add_drive

 int
 guestfs_add_drive (guestfs_h *g,
                    const char *filename);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_add_drive_opts" with no optional arguments.

(Added in 0.3)

guestfs_add_drive_opts

 int
 guestfs_add_drive_opts (guestfs_h *g,
                         const char *filename,
                         ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_ADD_DRIVE_OPTS_READONLY, int readonly,
 GUESTFS_ADD_DRIVE_OPTS_FORMAT, const char *format,
 GUESTFS_ADD_DRIVE_OPTS_IFACE, const char *iface,
 GUESTFS_ADD_DRIVE_OPTS_NAME, const char *name,
 GUESTFS_ADD_DRIVE_OPTS_LABEL, const char *label,
 GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, const char *protocol,
 GUESTFS_ADD_DRIVE_OPTS_SERVER, char *const *server,
 GUESTFS_ADD_DRIVE_OPTS_USERNAME, const char *username,
 GUESTFS_ADD_DRIVE_OPTS_SECRET, const char *secret,
 GUESTFS_ADD_DRIVE_OPTS_CACHEMODE, const char *cachemode,
 GUESTFS_ADD_DRIVE_OPTS_DISCARD, const char *discard,

This function adds a disk image called filename to the handle. filename may be a regular host file or a host device.

When this function is called before guestfs_launch (the usual case) then the first time you call this function, the disk appears in the API as /dev/sda, the second time as /dev/sdb, and so on.

In libguestfs ≥ 1.20 you can also call this function after launch (with some restrictions). This is called "hotplugging". When hotplugging, you must specify a label so that the new disk gets a predictable name. For more information see "HOTPLUGGING" in guestfs(3).

You don't necessarily need to be root when using libguestfs. However you obviously do need sufficient permissions to access the filename for whatever operations you want to perform (ie. read access if you just want to read the image or write access if you want to modify the image).

This call checks that filename exists.

filename may be the special string "/dev/null". See "NULL DISKS" in guestfs(3).

The optional arguments are:

readonly

If true then the image is treated as read-only. Writes are still allowed, but they are stored in a temporary snapshot overlay which is discarded at the end. The disk that you add is not modified.

format

This forces the image format. If you omit this (or use guestfs_add_drive or guestfs_add_drive_ro) then the format is automatically detected. Possible formats include raw and qcow2.

Automatic detection of the format opens you up to a potential security hole when dealing with untrusted raw-format images. See CVE-2010-3851 and RHBZ#642934. Specifying the format closes this security hole.

iface

This rarely-used option lets you emulate the behaviour of the deprecated guestfs_add_drive_with_if call (q.v.)

name

The name the drive had in the original guest, e.g. /dev/sdb. This is used as a hint to the guest inspection process if it is available.

label

Give the disk a label. The label should be a unique, short string using only ASCII characters [a-zA-Z]. As well as its usual name in the API (such as /dev/sda), the drive will also be named /dev/disk/guestfs/label.

See "DISK LABELS" in guestfs(3).

protocol

The optional protocol argument can be used to select an alternate source protocol.

See also: "REMOTE STORAGE" in guestfs(3).

protocol = "file"

filename is interpreted as a local file or device. This is the default if the optional protocol parameter is omitted.

protocol = "ftp"|"ftps"|"http"|"https"|"tftp"

Connect to a remote FTP, HTTP or TFTP server. The server parameter must also be supplied - see below.

See also: "FTP, HTTP AND TFTP" in guestfs(3)

protocol = "gluster"

Connect to the GlusterFS server. The server parameter must also be supplied - see below.

See also: "GLUSTER" in guestfs(3)

protocol = "iscsi"

Connect to the iSCSI server. The server parameter must also be supplied - see below.

See also: "ISCSI" in guestfs(3).

protocol = "nbd"

Connect to the Network Block Device server. The server parameter must also be supplied - see below.

See also: "NETWORK BLOCK DEVICE" in guestfs(3).

protocol = "rbd"

Connect to the Ceph (librbd/RBD) server. The server parameter must also be supplied - see below. The username parameter may be supplied. See below. The secret parameter may be supplied. See below.

See also: "CEPH" in guestfs(3).

protocol = "sheepdog"

Connect to the Sheepdog server. The server parameter may also be supplied - see below.

See also: "SHEEPDOG" in guestfs(3).

protocol = "ssh"

Connect to the Secure Shell (ssh) server.

The server parameter must be supplied. The username parameter may be supplied. See below.

See also: "SSH" in guestfs(3).

server

For protocols which require access to a remote server, this is a list of server(s).

 Protocol       Number of servers required
 --------       --------------------------
 file           List must be empty or param not used at all
 ftp|ftps|http|https|tftp  Exactly one
 gluster        Exactly one
 iscsi          Exactly one
 nbd            Exactly one
 rbd            Zero or more
 sheepdog       Zero or more
 ssh            Exactly one

Each list element is a string specifying a server. The string must be in one of the following formats:

 hostname
 hostname:port
 tcp:hostname
 tcp:hostname:port
 unix:/path/to/socket

If the port number is omitted, then the standard port number for the protocol is used (see /etc/services).

username

For the ftp, ftps, http, https, iscsi, rbd, ssh and tftp protocols, this specifies the remote username.

If not given, then the local username is used for ssh, and no authentication is attempted for ceph. But note this sometimes may give unexpected results, for example if using the libvirt backend and if the libvirt backend is configured to start the qemu appliance as a special user such as qemu.qemu. If in doubt, specify the remote username you want.

secret

For the rbd protocol only, this specifies the 'secret' to use when connecting to the remote device.

If not given, then a secret matching the given username will be looked up in the default keychain locations, or if no username is given, then no authentication will be used.

cachemode

Choose whether or not libguestfs will obey sync operations (safe but slow) or not (unsafe but fast). The possible values for this string are:

cachemode = "writeback"

This is the default.

Write operations in the API do not return until a write(2) call has completed in the host [but note this does not imply that anything gets written to disk].

Sync operations in the API, including implicit syncs caused by filesystem journalling, will not return until an fdatasync(2) call has completed in the host, indicating that data has been committed to disk.

cachemode = "unsafe"

In this mode, there are no guarantees. Libguestfs may cache anything and ignore sync requests. This is suitable only for scratch or temporary disks.

discard

Enable or disable discard (a.k.a. trim or unmap) support on this drive. If enabled, operations such as guestfs_fstrim will be able to discard / make thin / punch holes in the underlying host file or device.

Possible discard settings are:

discard = "disable"

Disable discard support. This is the default.

discard = "enable"

Enable discard support. Fail if discard is not possible.

discard = "besteffort"

Enable discard support if possible, but don't fail if it is not supported.

Since not all backends and not all underlying systems support discard, this is a good choice if you want to use discard if possible, but don't mind if it doesn't work.

This function returns 0 on success or -1 on error.

(Added in 1.5.23)

guestfs_add_drive_opts_va

 int
 guestfs_add_drive_opts_va (guestfs_h *g,
                            const char *filename,
                            va_list args);

This is the "va_list variant" of "guestfs_add_drive_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_add_drive_opts_argv

 int
 guestfs_add_drive_opts_argv (guestfs_h *g,
                              const char *filename,
                              const struct guestfs_add_drive_opts_argv *optargs);

This is the "argv variant" of "guestfs_add_drive_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_add_drive_ro

 int
 guestfs_add_drive_ro (guestfs_h *g,
                       const char *filename);

This function is the equivalent of calling guestfs_add_drive_opts with the optional parameter GUESTFS_ADD_DRIVE_OPTS_READONLY set to 1, so the disk is added read-only, with the format being detected automatically.

This function returns 0 on success or -1 on error.

(Added in 1.0.38)

guestfs_add_drive_ro_with_if

 int
 guestfs_add_drive_ro_with_if (guestfs_h *g,
                               const char *filename,
                               const char *iface);

This function is deprecated. In new code, use the "guestfs_add_drive" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This is the same as guestfs_add_drive_ro but it allows you to specify the QEMU interface emulation to use at run time.

This function returns 0 on success or -1 on error.

(Added in 1.0.84)

guestfs_add_drive_scratch

 int
 guestfs_add_drive_scratch (guestfs_h *g,
                            int64_t size,
                            ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_ADD_DRIVE_SCRATCH_NAME, const char *name,
 GUESTFS_ADD_DRIVE_SCRATCH_LABEL, const char *label,

This command adds a temporary scratch drive to the handle. The size parameter is the virtual size (in bytes). The scratch drive is blank initially (all reads return zeroes until you start writing to it). The drive is deleted when the handle is closed.

The optional arguments name and label are passed through to guestfs_add_drive.

This function returns 0 on success or -1 on error.

(Added in 1.23.10)

guestfs_add_drive_scratch_va

 int
 guestfs_add_drive_scratch_va (guestfs_h *g,
                               int64_t size,
                               va_list args);

This is the "va_list variant" of "guestfs_add_drive_scratch".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_add_drive_scratch_argv

 int
 guestfs_add_drive_scratch_argv (guestfs_h *g,
                                 int64_t size,
                                 const struct guestfs_add_drive_scratch_argv *optargs);

This is the "argv variant" of "guestfs_add_drive_scratch".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_add_drive_with_if

 int
 guestfs_add_drive_with_if (guestfs_h *g,
                            const char *filename,
                            const char *iface);

This function is deprecated. In new code, use the "guestfs_add_drive" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This is the same as guestfs_add_drive but it allows you to specify the QEMU interface emulation to use at run time.

This function returns 0 on success or -1 on error.

(Added in 1.0.84)

guestfs_aug_clear

 int
 guestfs_aug_clear (guestfs_h *g,
                    const char *augpath);

Set the value associated with path to NULL. This is the same as the augtool(1) clear command.

This function returns 0 on success or -1 on error.

(Added in 1.3.4)

guestfs_aug_close

 int
 guestfs_aug_close (guestfs_h *g);

Close the current Augeas handle and free up any resources used by it. After calling this, you have to call guestfs_aug_init again before you can use any other Augeas functions.

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_defnode

 struct guestfs_int_bool *
 guestfs_aug_defnode (guestfs_h *g,
                      const char *name,
                      const char *expr,
                      const char *val);

Defines a variable name whose value is the result of evaluating expr.

If expr evaluates to an empty nodeset, a node is created, equivalent to calling guestfs_aug_set expr, value. name will be the nodeset containing that single node.

On success this returns a pair containing the number of nodes in the nodeset, and a boolean flag if a node was created.

This function returns a struct guestfs_int_bool *, or NULL if there was an error. The caller must call guestfs_free_int_bool after use.

(Added in 0.7)

guestfs_aug_defvar

 int
 guestfs_aug_defvar (guestfs_h *g,
                     const char *name,
                     const char *expr);

Defines an Augeas variable name whose value is the result of evaluating expr. If expr is NULL, then name is undefined.

On success this returns the number of nodes in expr, or 0 if expr evaluates to something which is not a nodeset.

On error this function returns -1.

(Added in 0.7)

guestfs_aug_get

 char *
 guestfs_aug_get (guestfs_h *g,
                  const char *augpath);

Look up the value associated with path. If path matches exactly one node, the value is returned.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 0.7)

guestfs_aug_init

 int
 guestfs_aug_init (guestfs_h *g,
                   const char *root,
                   int flags);

Create a new Augeas handle for editing configuration files. If there was any previous Augeas handle associated with this guestfs session, then it is closed.

You must call this before using any other guestfs_aug_* commands.

root is the filesystem root. root must not be NULL, use / instead.

The flags are the same as the flags defined in <augeas.h>, the logical or of the following integers:

AUG_SAVE_BACKUP = 1

Keep the original file with a .augsave extension.

AUG_SAVE_NEWFILE = 2

Save changes into a file with extension .augnew, and do not overwrite original. Overrides AUG_SAVE_BACKUP.

AUG_TYPE_CHECK = 4

Typecheck lenses.

This option is only useful when debugging Augeas lenses. Use of this option may require additional memory for the libguestfs appliance. You may need to set the LIBGUESTFS_MEMSIZE environment variable or call guestfs_set_memsize.

AUG_NO_STDINC = 8

Do not use standard load path for modules.

AUG_SAVE_NOOP = 16

Make save a no-op, just record what would have been changed.

AUG_NO_LOAD = 32

Do not load the tree in guestfs_aug_init.

To close the handle, you can call guestfs_aug_close.

To find out more about Augeas, see http://augeas.net/.

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_insert

 int
 guestfs_aug_insert (guestfs_h *g,
                     const char *augpath,
                     const char *label,
                     int before);

Create a new sibling label for path, inserting it into the tree before or after path (depending on the boolean flag before).

path must match exactly one existing node in the tree, and label must be a label, ie. not contain /, * or end with a bracketed index [N].

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_label

 char *
 guestfs_aug_label (guestfs_h *g,
                    const char *augpath);

The label (name of the last element) of the Augeas path expression augpath is returned. augpath must match exactly one node, else this function returns an error.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.23.14)

guestfs_aug_load

 int
 guestfs_aug_load (guestfs_h *g);

Load files into the tree.

See aug_load in the Augeas documentation for the full gory details.

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_ls

 char **
 guestfs_aug_ls (guestfs_h *g,
                 const char *augpath);

This is just a shortcut for listing guestfs_aug_match path/* and sorting the resulting nodes into alphabetical order.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.8)

guestfs_aug_match

 char **
 guestfs_aug_match (guestfs_h *g,
                    const char *augpath);

Returns a list of paths which match the path expression path. The returned paths are sufficiently qualified so that they match exactly one node in the current tree.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.7)

guestfs_aug_mv

 int
 guestfs_aug_mv (guestfs_h *g,
                 const char *src,
                 const char *dest);

Move the node src to dest. src must match exactly one node. dest is overwritten if it exists.

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_rm

 int
 guestfs_aug_rm (guestfs_h *g,
                 const char *augpath);

Remove path and all of its children.

On success this returns the number of entries which were removed.

On error this function returns -1.

(Added in 0.7)

guestfs_aug_save

 int
 guestfs_aug_save (guestfs_h *g);

This writes all pending changes to disk.

The flags which were passed to guestfs_aug_init affect exactly how files are saved.

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_set

 int
 guestfs_aug_set (guestfs_h *g,
                  const char *augpath,
                  const char *val);

Set the value associated with path to val.

In the Augeas API, it is possible to clear a node by setting the value to NULL. Due to an oversight in the libguestfs API you cannot do that with this call. Instead you must use the guestfs_aug_clear call.

This function returns 0 on success or -1 on error.

(Added in 0.7)

guestfs_aug_setm

 int
 guestfs_aug_setm (guestfs_h *g,
                   const char *base,
                   const char *sub,
                   const char *val);

Change multiple Augeas nodes in a single operation. base is an expression matching multiple nodes. sub is a path expression relative to base. All nodes matching base are found, and then for each node, sub is changed to val. sub may also be NULL in which case the base nodes are modified.

This returns the number of nodes modified.

On error this function returns -1.

(Added in 1.23.14)

guestfs_available

 int
 guestfs_available (guestfs_h *g,
                    char *const *groups);

This command is used to check the availability of some groups of functionality in the appliance, which not all builds of the libguestfs appliance will be able to provide.

The libguestfs groups, and the functions that those groups correspond to, are listed in "AVAILABILITY" in guestfs(3). You can also fetch this list at runtime by calling guestfs_available_all_groups.

The argument groups is a list of group names, eg: ["inotify", "augeas"] would check for the availability of the Linux inotify functions and Augeas (configuration file editing) functions.

The command returns no error if all requested groups are available.

It fails with an error if one or more of the requested groups is unavailable in the appliance.

If an unknown group name is included in the list of groups then an error is always returned.

Notes:

See also guestfs_filesystem_available.

This function returns 0 on success or -1 on error.

(Added in 1.0.80)

guestfs_available_all_groups

 char **
 guestfs_available_all_groups (guestfs_h *g);

This command returns a list of all optional groups that this daemon knows about. Note this returns both supported and unsupported groups. To find out which ones the daemon can actually support you have to call guestfs_available / guestfs_feature_available on each member of the returned list.

See also guestfs_available, guestfs_feature_available and "AVAILABILITY" in guestfs(3).

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.3.15)

guestfs_base64_in

 int
 guestfs_base64_in (guestfs_h *g,
                    const char *base64file,
                    const char *filename);

This command uploads base64-encoded data from base64file to filename.

This function returns 0 on success or -1 on error.

(Added in 1.3.5)

guestfs_base64_out

 int
 guestfs_base64_out (guestfs_h *g,
                     const char *filename,
                     const char *base64file);

This command downloads the contents of filename, writing it out to local file base64file encoded as base64.

This function returns 0 on success or -1 on error.

(Added in 1.3.5)

guestfs_blkdiscard

 int
 guestfs_blkdiscard (guestfs_h *g,
                     const char *device);

This discards all blocks on the block device device, giving the free space back to the host.

This operation requires support in libguestfs, the host filesystem, qemu and the host kernel. If this support isn't present it may give an error or even appear to run but do nothing. You must also set the discard attribute on the underlying drive (see guestfs_add_drive_opts).

This function returns 0 on success or -1 on error.

(Added in 1.25.44)

guestfs_blkdiscardzeroes

 int
 guestfs_blkdiscardzeroes (guestfs_h *g,
                           const char *device);

This call returns true if blocks on device that have been discarded by a call to guestfs_blkdiscard are returned as blocks of zero bytes when read the next time.

If it returns false, then it may be that discarded blocks are read as stale or random data.

This function returns a C truth value on success or -1 on error.

(Added in 1.25.44)

guestfs_blkid

 char **
 guestfs_blkid (guestfs_h *g,
                const char *device);

This command returns block device attributes for device. The following fields are usually present in the returned hash. Other fields may also be present.

UUID

The uuid of this device.

LABEL

The label of this device.

VERSION

The version of blkid command.

TYPE

The filesystem type or RAID of this device.

USAGE

The usage of this device, for example filesystem or raid.

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.15.9)

guestfs_blockdev_flushbufs

 int
 guestfs_blockdev_flushbufs (guestfs_h *g,
                             const char *device);

This tells the kernel to flush internal buffers associated with device.

This uses the blockdev(8) command.

This function returns 0 on success or -1 on error.

(Added in 0.9.3)

guestfs_blockdev_getbsz

 int
 guestfs_blockdev_getbsz (guestfs_h *g,
                          const char *device);

This returns the block size of a device.

Note: this is different from both size in blocks and filesystem block size. Also this setting is not really used by anything. You should probably not use it for anything. Filesystems have their own idea about what block size to choose.

This uses the blockdev(8) command.

On error this function returns -1.

(Added in 0.9.3)

guestfs_blockdev_getro

 int
 guestfs_blockdev_getro (guestfs_h *g,
                         const char *device);

Returns a boolean indicating if the block device is read-only (true if read-only, false if not).

This uses the blockdev(8) command.

This function returns a C truth value on success or -1 on error.

(Added in 0.9.3)

guestfs_blockdev_getsize64

 int64_t
 guestfs_blockdev_getsize64 (guestfs_h *g,
                             const char *device);

This returns the size of the device in bytes.

See also guestfs_blockdev_getsz.

This uses the blockdev(8) command.

On error this function returns -1.

(Added in 0.9.3)

guestfs_blockdev_getss

 int
 guestfs_blockdev_getss (guestfs_h *g,
                         const char *device);

This returns the size of sectors on a block device. Usually 512, but can be larger for modern devices.

(Note, this is not the size in sectors, use guestfs_blockdev_getsz for that).

This uses the blockdev(8) command.

On error this function returns -1.

(Added in 0.9.3)

guestfs_blockdev_getsz

 int64_t
 guestfs_blockdev_getsz (guestfs_h *g,
                         const char *device);

This returns the size of the device in units of 512-byte sectors (even if the sectorsize isn't 512 bytes ... weird).

See also guestfs_blockdev_getss for the real sector size of the device, and guestfs_blockdev_getsize64 for the more useful size in bytes.

This uses the blockdev(8) command.

On error this function returns -1.

(Added in 0.9.3)

guestfs_blockdev_rereadpt

 int
 guestfs_blockdev_rereadpt (guestfs_h *g,
                            const char *device);

Reread the partition table on device.

This uses the blockdev(8) command.

This function returns 0 on success or -1 on error.

(Added in 0.9.3)

guestfs_blockdev_setbsz

 int
 guestfs_blockdev_setbsz (guestfs_h *g,
                          const char *device,
                          int blocksize);

This function is deprecated. In new code, use the "guestfs_mkfs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This call does nothing and has never done anything because of a bug in blockdev. Do not use it.

If you need to set the filesystem block size, use the blocksize option of guestfs_mkfs.

This function returns 0 on success or -1 on error.

(Added in 0.9.3)

guestfs_blockdev_setro

 int
 guestfs_blockdev_setro (guestfs_h *g,
                         const char *device);

Sets the block device named device to read-only.

This uses the blockdev(8) command.

This function returns 0 on success or -1 on error.

(Added in 0.9.3)

guestfs_blockdev_setrw

 int
 guestfs_blockdev_setrw (guestfs_h *g,
                         const char *device);

Sets the block device named device to read-write.

This uses the blockdev(8) command.

This function returns 0 on success or -1 on error.

(Added in 0.9.3)

guestfs_btrfs_device_add

 int
 guestfs_btrfs_device_add (guestfs_h *g,
                           char *const *devices,
                           const char *fs);

Add the list of device(s) in devices to the btrfs filesystem mounted at fs. If devices is an empty list, this does nothing.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_device_delete

 int
 guestfs_btrfs_device_delete (guestfs_h *g,
                              char *const *devices,
                              const char *fs);

Remove the devices from the btrfs filesystem mounted at fs. If devices is an empty list, this does nothing.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_filesystem_balance

 int
 guestfs_btrfs_filesystem_balance (guestfs_h *g,
                                   const char *fs);

Balance the chunks in the btrfs filesystem mounted at fs across the underlying devices.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_filesystem_resize

 int
 guestfs_btrfs_filesystem_resize (guestfs_h *g,
                                  const char *mountpoint,
                                  ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_BTRFS_FILESYSTEM_RESIZE_SIZE, int64_t size,

This command resizes a btrfs filesystem.

Note that unlike other resize calls, the filesystem has to be mounted and the parameter is the mountpoint not the device (this is a requirement of btrfs itself).

The optional parameters are:

size

The new size (in bytes) of the filesystem. If omitted, the filesystem is resized to the maximum size.

See also btrfs(8).

This function returns 0 on success or -1 on error.

(Added in 1.11.17)

guestfs_btrfs_filesystem_resize_va

 int
 guestfs_btrfs_filesystem_resize_va (guestfs_h *g,
                                     const char *mountpoint,
                                     va_list args);

This is the "va_list variant" of "guestfs_btrfs_filesystem_resize".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_btrfs_filesystem_resize_argv

 int
 guestfs_btrfs_filesystem_resize_argv (guestfs_h *g,
                                       const char *mountpoint,
                                       const struct guestfs_btrfs_filesystem_resize_argv *optargs);

This is the "argv variant" of "guestfs_btrfs_filesystem_resize".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_btrfs_filesystem_sync

 int
 guestfs_btrfs_filesystem_sync (guestfs_h *g,
                                const char *fs);

Force sync on the btrfs filesystem mounted at fs.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_fsck

 int
 guestfs_btrfs_fsck (guestfs_h *g,
                     const char *device,
                     ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_BTRFS_FSCK_SUPERBLOCK, int64_t superblock,
 GUESTFS_BTRFS_FSCK_REPAIR, int repair,

Used to check a btrfs filesystem, device is the device file where the filesystem is stored.

This function returns 0 on success or -1 on error.

(Added in 1.17.43)

guestfs_btrfs_fsck_va

 int
 guestfs_btrfs_fsck_va (guestfs_h *g,
                        const char *device,
                        va_list args);

This is the "va_list variant" of "guestfs_btrfs_fsck".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_btrfs_fsck_argv

 int
 guestfs_btrfs_fsck_argv (guestfs_h *g,
                          const char *device,
                          const struct guestfs_btrfs_fsck_argv *optargs);

This is the "argv variant" of "guestfs_btrfs_fsck".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_btrfs_set_seeding

 int
 guestfs_btrfs_set_seeding (guestfs_h *g,
                            const char *device,
                            int seeding);

Enable or disable the seeding feature of a device that contains a btrfs filesystem.

This function returns 0 on success or -1 on error.

(Added in 1.17.43)

guestfs_btrfs_subvolume_create

 int
 guestfs_btrfs_subvolume_create (guestfs_h *g,
                                 const char *dest);

Create a btrfs subvolume. The dest argument is the destination directory and the name of the snapshot, in the form /path/to/dest/name.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_subvolume_delete

 int
 guestfs_btrfs_subvolume_delete (guestfs_h *g,
                                 const char *subvolume);

Delete the named btrfs subvolume.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_subvolume_list

 struct guestfs_btrfssubvolume_list *
 guestfs_btrfs_subvolume_list (guestfs_h *g,
                               const char *fs);

List the btrfs snapshots and subvolumes of the btrfs filesystem which is mounted at fs.

This function returns a struct guestfs_btrfssubvolume_list *, or NULL if there was an error. The caller must call guestfs_free_btrfssubvolume_list after use.

(Added in 1.17.35)

guestfs_btrfs_subvolume_set_default

 int
 guestfs_btrfs_subvolume_set_default (guestfs_h *g,
                                      int64_t id,
                                      const char *fs);

Set the subvolume of the btrfs filesystem fs which will be mounted by default. See guestfs_btrfs_subvolume_list to get a list of subvolumes.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_btrfs_subvolume_snapshot

 int
 guestfs_btrfs_subvolume_snapshot (guestfs_h *g,
                                   const char *source,
                                   const char *dest);

Create a writable snapshot of the btrfs subvolume source. The dest argument is the destination directory and the name of the snapshot, in the form /path/to/dest/name.

This function returns 0 on success or -1 on error.

(Added in 1.17.35)

guestfs_canonical_device_name

 char *
 guestfs_canonical_device_name (guestfs_h *g,
                                const char *device);

This utility function is useful when displaying device names to the user. It takes a number of irregular device names and returns them in a consistent format:

/dev/hdX
/dev/vdX

These are returned as /dev/sdX. Note this works for device names and partition names. This is approximately the reverse of the algorithm described in "BLOCK DEVICE NAMING" in guestfs(3).

/dev/mapper/VG-LV
/dev/dm-N

Converted to /dev/VG/LV form using guestfs_lvm_canonical_lvm_name.

Other strings are returned unmodified.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.7)

guestfs_cap_get_file

 char *
 guestfs_cap_get_file (guestfs_h *g,
                       const char *path);

This function returns the Linux capabilities attached to path. The capabilities set is returned in text form (see cap_to_text(3)).

If no capabilities are attached to a file, an empty string is returned.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.63)

guestfs_cap_set_file

 int
 guestfs_cap_set_file (guestfs_h *g,
                       const char *path,
                       const char *cap);

This function sets the Linux capabilities attached to path. The capabilities set cap should be passed in text form (see cap_from_text(3)).

This function returns 0 on success or -1 on error.

(Added in 1.19.63)

guestfs_case_sensitive_path

 char *
 guestfs_case_sensitive_path (guestfs_h *g,
                              const char *path);

This can be used to resolve case insensitive paths on a filesystem which is case sensitive. The use case is to resolve paths which you have read from Windows configuration files or the Windows Registry, to the true path.

The command handles a peculiarity of the Linux ntfs-3g filesystem driver (and probably others), which is that although the underlying filesystem is case-insensitive, the driver exports the filesystem to Linux as case-sensitive.

One consequence of this is that special directories such as c:\windows may appear as /WINDOWS or /windows (or other things) depending on the precise details of how they were created. In Windows itself this would not be a problem.

Bug or feature? You decide: http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1

guestfs_case_sensitive_path attempts to resolve the true case of each element in the path. It will return a resolved path if either the full path or its parent directory exists. If the parent directory exists but the full path does not, the case of the parent directory will be correctly resolved, and the remainder appended unmodified. For example, if the file "/Windows/System32/netkvm.sys" exists:

guestfs_case_sensitive_path ("/windows/system32/netkvm.sys")

"Windows/System32/netkvm.sys"

guestfs_case_sensitive_path ("/windows/system32/NoSuchFile")

"Windows/System32/NoSuchFile"

guestfs_case_sensitive_path ("/windows/system33/netkvm.sys")

ERROR

Note: Because of the above behaviour, guestfs_case_sensitive_path cannot be used to check for the existence of a file.

Note: This function does not handle drive names, backslashes etc.

See also guestfs_realpath.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.75)

guestfs_cat

 char *
 guestfs_cat (guestfs_h *g,
              const char *path);

Return the contents of the file named path.

Because, in C, this function returns a char *, there is no way to differentiate between a \0 character in a file and end of string. To handle binary files, use the guestfs_read_file or guestfs_download functions.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 0.4)

guestfs_checksum

 char *
 guestfs_checksum (guestfs_h *g,
                   const char *csumtype,
                   const char *path);

This call computes the MD5, SHAx or CRC checksum of the file named path.

The type of checksum to compute is given by the csumtype parameter which must have one of the following values:

crc

Compute the cyclic redundancy check (CRC) specified by POSIX for the cksum command.

md5

Compute the MD5 hash (using the md5sum program).

sha1

Compute the SHA1 hash (using the sha1sum program).

sha224

Compute the SHA224 hash (using the sha224sum program).

sha256

Compute the SHA256 hash (using the sha256sum program).

sha384

Compute the SHA384 hash (using the sha384sum program).

sha512

Compute the SHA512 hash (using the sha512sum program).

The checksum is returned as a printable string.

To get the checksum for a device, use guestfs_checksum_device.

To get the checksums for many files, use guestfs_checksums_out.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.2)

guestfs_checksum_device

 char *
 guestfs_checksum_device (guestfs_h *g,
                          const char *csumtype,
                          const char *device);

This call computes the MD5, SHAx or CRC checksum of the contents of the device named device. For the types of checksums supported see the guestfs_checksum command.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.3.2)

guestfs_checksums_out

 int
 guestfs_checksums_out (guestfs_h *g,
                        const char *csumtype,
                        const char *directory,
                        const char *sumsfile);

This command computes the checksums of all regular files in directory and then emits a list of those checksums to the local output file sumsfile.

This can be used for verifying the integrity of a virtual machine. However to be properly secure you should pay attention to the output of the checksum command (it uses the ones from GNU coreutils). In particular when the filename is not printable, coreutils uses a special backslash syntax. For more information, see the GNU coreutils info file.

This function returns 0 on success or -1 on error.

(Added in 1.3.7)

guestfs_chmod

 int
 guestfs_chmod (guestfs_h *g,
                int mode,
                const char *path);

Change the mode (permissions) of path to mode. Only numeric modes are supported.

Note: When using this command from guestfish, mode by default would be decimal, unless you prefix it with 0 to get octal, ie. use 0700 not 700.

The mode actually set is affected by the umask.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_chown

 int
 guestfs_chown (guestfs_h *g,
                int owner,
                int group,
                const char *path);

Change the file owner to owner and group to group.

Only numeric uid and gid are supported. If you want to use names, you will need to locate and parse the password file yourself (Augeas support makes this relatively easy).

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_clear_backend_setting

 int
 guestfs_clear_backend_setting (guestfs_h *g,
                                const char *name);

If there is a backend setting string matching "name" or beginning with "name=", then that string is removed from the backend settings.

This call returns the number of strings which were removed (which may be 0, 1 or greater than 1).

See "BACKEND" in guestfs(3), "BACKEND SETTINGS" in guestfs(3).

On error this function returns -1.

guestfs_command

 char *
 guestfs_command (guestfs_h *g,
                  char *const *arguments);

This call runs a command from the guest filesystem. The filesystem must be mounted, and must contain a compatible operating system (ie. something Linux, with the same or compatible processor architecture).

The single parameter is an argv-style list of arguments. The first element is the name of the program to run. Subsequent elements are parameters. The list must be non-empty (ie. must contain a program name). Note that the command runs directly, and is not invoked via the shell (see guestfs_sh).

The return value is anything printed to stdout by the command.

If the command returns a non-zero exit status, then this function returns an error message. The error message string is the content of stderr from the command.

The $PATH environment variable will contain at least /usr/bin and /bin. If you require a program from another location, you should provide the full path in the first parameter.

Shared libraries and data files required by the program must be available on filesystems which are mounted in the correct places. It is the caller's responsibility to ensure all filesystems that are needed are mounted at the right locations.

This function returns a string, or NULL on error. The caller must free the returned string after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 0.9.1)

guestfs_command_lines

 char **
 guestfs_command_lines (guestfs_h *g,
                        char *const *arguments);

This is the same as guestfs_command, but splits the result into a list of lines.

See also: guestfs_sh_lines

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 0.9.1)

guestfs_compress_device_out

 int
 guestfs_compress_device_out (guestfs_h *g,
                              const char *ctype,
                              const char *device,
                              const char *zdevice,
                              ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COMPRESS_DEVICE_OUT_LEVEL, int level,

This command compresses device and writes it out to the local file zdevice.

The ctype and optional level parameters have the same meaning as in guestfs_compress_out.

This function returns 0 on success or -1 on error.

(Added in 1.13.15)

guestfs_compress_device_out_va

 int
 guestfs_compress_device_out_va (guestfs_h *g,
                                 const char *ctype,
                                 const char *device,
                                 const char *zdevice,
                                 va_list args);

This is the "va_list variant" of "guestfs_compress_device_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_compress_device_out_argv

 int
 guestfs_compress_device_out_argv (guestfs_h *g,
                                   const char *ctype,
                                   const char *device,
                                   const char *zdevice,
                                   const struct guestfs_compress_device_out_argv *optargs);

This is the "argv variant" of "guestfs_compress_device_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_compress_out

 int
 guestfs_compress_out (guestfs_h *g,
                       const char *ctype,
                       const char *file,
                       const char *zfile,
                       ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COMPRESS_OUT_LEVEL, int level,

This command compresses file and writes it out to the local file zfile.

The compression program used is controlled by the ctype parameter. Currently this includes: compress, gzip, bzip2, xz or lzop. Some compression types may not be supported by particular builds of libguestfs, in which case you will get an error containing the substring "not supported".

The optional level parameter controls compression level. The meaning and default for this parameter depends on the compression program being used.

This function returns 0 on success or -1 on error.

(Added in 1.13.15)

guestfs_compress_out_va

 int
 guestfs_compress_out_va (guestfs_h *g,
                          const char *ctype,
                          const char *file,
                          const char *zfile,
                          va_list args);

This is the "va_list variant" of "guestfs_compress_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_compress_out_argv

 int
 guestfs_compress_out_argv (guestfs_h *g,
                            const char *ctype,
                            const char *file,
                            const char *zfile,
                            const struct guestfs_compress_out_argv *optargs);

This is the "argv variant" of "guestfs_compress_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_config

 int
 guestfs_config (guestfs_h *g,
                 const char *hvparam,
                 const char *hvvalue);

This can be used to add arbitrary hypervisor parameters of the form -param value. Actually it's not quite arbitrary - we prevent you from setting some parameters which would interfere with parameters that we use.

The first character of hvparam string must be a - (dash).

hvvalue can be NULL.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_copy_attributes

 int
 guestfs_copy_attributes (guestfs_h *g,
                          const char *src,
                          const char *dest,
                          ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COPY_ATTRIBUTES_ALL, int all,
 GUESTFS_COPY_ATTRIBUTES_MODE, int mode,
 GUESTFS_COPY_ATTRIBUTES_XATTRIBUTES, int xattributes,
 GUESTFS_COPY_ATTRIBUTES_OWNERSHIP, int ownership,

Copy the attributes of a path (which can be a file or a directory) to another path.

By default no attribute is copied, so make sure to specify any (or all to copy everything).

The optional arguments specify which attributes can be copied:

mode

Copy part of the file mode from source to destination. Only the UNIX permissions and the sticky/setuid/setgid bits can be copied.

xattributes

Copy the Linux extended attributes (xattrs) from source to destination. This flag does nothing if the linuxxattrs feature is not available (see guestfs_feature_available).

ownership

Copy the owner uid and the group gid of source to destination.

all

Copy all the attributes from source to destination. Enabling it enables all the other flags, if they are not specified already.

This function returns 0 on success or -1 on error.

(Added in 1.25.21)

guestfs_copy_attributes_va

 int
 guestfs_copy_attributes_va (guestfs_h *g,
                             const char *src,
                             const char *dest,
                             va_list args);

This is the "va_list variant" of "guestfs_copy_attributes".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_attributes_argv

 int
 guestfs_copy_attributes_argv (guestfs_h *g,
                               const char *src,
                               const char *dest,
                               const struct guestfs_copy_attributes_argv *optargs);

This is the "argv variant" of "guestfs_copy_attributes".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_device_to_device

 int
 guestfs_copy_device_to_device (guestfs_h *g,
                                const char *src,
                                const char *dest,
                                ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COPY_DEVICE_TO_DEVICE_SRCOFFSET, int64_t srcoffset,
 GUESTFS_COPY_DEVICE_TO_DEVICE_DESTOFFSET, int64_t destoffset,
 GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, int64_t size,
 GUESTFS_COPY_DEVICE_TO_DEVICE_SPARSE, int sparse,

The four calls guestfs_copy_device_to_device, guestfs_copy_device_to_file, guestfs_copy_file_to_device, and guestfs_copy_file_to_file let you copy from a source (device|file) to a destination (device|file).

Partial copies can be made since you can specify optionally the source offset, destination offset and size to copy. These values are all specified in bytes. If not given, the offsets both default to zero, and the size defaults to copying as much as possible until we hit the end of the source.

The source and destination may be the same object. However overlapping regions may not be copied correctly.

If the destination is a file, it is created if required. If the destination file is not large enough, it is extended.

If the sparse flag is true then the call avoids writing blocks that contain only zeroes, which can help in some situations where the backing disk is thin-provisioned. Note that unless the target is already zeroed, using this option will result in incorrect copying.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.13.25)

guestfs_copy_device_to_device_va

 int
 guestfs_copy_device_to_device_va (guestfs_h *g,
                                   const char *src,
                                   const char *dest,
                                   va_list args);

This is the "va_list variant" of "guestfs_copy_device_to_device".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_device_to_device_argv

 int
 guestfs_copy_device_to_device_argv (guestfs_h *g,
                                     const char *src,
                                     const char *dest,
                                     const struct guestfs_copy_device_to_device_argv *optargs);

This is the "argv variant" of "guestfs_copy_device_to_device".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_device_to_file

 int
 guestfs_copy_device_to_file (guestfs_h *g,
                              const char *src,
                              const char *dest,
                              ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COPY_DEVICE_TO_FILE_SRCOFFSET, int64_t srcoffset,
 GUESTFS_COPY_DEVICE_TO_FILE_DESTOFFSET, int64_t destoffset,
 GUESTFS_COPY_DEVICE_TO_FILE_SIZE, int64_t size,
 GUESTFS_COPY_DEVICE_TO_FILE_SPARSE, int sparse,

See guestfs_copy_device_to_device for a general overview of this call.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.13.25)

guestfs_copy_device_to_file_va

 int
 guestfs_copy_device_to_file_va (guestfs_h *g,
                                 const char *src,
                                 const char *dest,
                                 va_list args);

This is the "va_list variant" of "guestfs_copy_device_to_file".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_device_to_file_argv

 int
 guestfs_copy_device_to_file_argv (guestfs_h *g,
                                   const char *src,
                                   const char *dest,
                                   const struct guestfs_copy_device_to_file_argv *optargs);

This is the "argv variant" of "guestfs_copy_device_to_file".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_file_to_device

 int
 guestfs_copy_file_to_device (guestfs_h *g,
                              const char *src,
                              const char *dest,
                              ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COPY_FILE_TO_DEVICE_SRCOFFSET, int64_t srcoffset,
 GUESTFS_COPY_FILE_TO_DEVICE_DESTOFFSET, int64_t destoffset,
 GUESTFS_COPY_FILE_TO_DEVICE_SIZE, int64_t size,
 GUESTFS_COPY_FILE_TO_DEVICE_SPARSE, int sparse,

See guestfs_copy_device_to_device for a general overview of this call.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.13.25)

guestfs_copy_file_to_device_va

 int
 guestfs_copy_file_to_device_va (guestfs_h *g,
                                 const char *src,
                                 const char *dest,
                                 va_list args);

This is the "va_list variant" of "guestfs_copy_file_to_device".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_file_to_device_argv

 int
 guestfs_copy_file_to_device_argv (guestfs_h *g,
                                   const char *src,
                                   const char *dest,
                                   const struct guestfs_copy_file_to_device_argv *optargs);

This is the "argv variant" of "guestfs_copy_file_to_device".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_file_to_file

 int
 guestfs_copy_file_to_file (guestfs_h *g,
                            const char *src,
                            const char *dest,
                            ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_COPY_FILE_TO_FILE_SRCOFFSET, int64_t srcoffset,
 GUESTFS_COPY_FILE_TO_FILE_DESTOFFSET, int64_t destoffset,
 GUESTFS_COPY_FILE_TO_FILE_SIZE, int64_t size,
 GUESTFS_COPY_FILE_TO_FILE_SPARSE, int sparse,

See guestfs_copy_device_to_device for a general overview of this call.

This is not the function you want for copying files. This is for copying blocks within existing files. See guestfs_cp, guestfs_cp_a and guestfs_mv for general file copying and moving functions.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.13.25)

guestfs_copy_file_to_file_va

 int
 guestfs_copy_file_to_file_va (guestfs_h *g,
                               const char *src,
                               const char *dest,
                               va_list args);

This is the "va_list variant" of "guestfs_copy_file_to_file".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_file_to_file_argv

 int
 guestfs_copy_file_to_file_argv (guestfs_h *g,
                                 const char *src,
                                 const char *dest,
                                 const struct guestfs_copy_file_to_file_argv *optargs);

This is the "argv variant" of "guestfs_copy_file_to_file".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_copy_size

 int
 guestfs_copy_size (guestfs_h *g,
                    const char *src,
                    const char *dest,
                    int64_t size);

This function is deprecated. In new code, use the "guestfs_copy_device_to_device" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command copies exactly size bytes from one source device or file src to another destination device or file dest.

Note this will fail if the source is too short or if the destination is not large enough.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.0.87)

guestfs_cp

 int
 guestfs_cp (guestfs_h *g,
             const char *src,
             const char *dest);

This copies a file from src to dest where dest is either a destination filename or destination directory.

This function returns 0 on success or -1 on error.

(Added in 1.0.18)

guestfs_cp_a

 int
 guestfs_cp_a (guestfs_h *g,
               const char *src,
               const char *dest);

This copies a file or directory from src to dest recursively using the cp -a command.

This function returns 0 on success or -1 on error.

(Added in 1.0.18)

guestfs_cp_r

 int
 guestfs_cp_r (guestfs_h *g,
               const char *src,
               const char *dest);

This copies a file or directory from src to dest recursively using the cp -rP command.

Most users should use guestfs_cp_a instead. This command is useful when you don't want to preserve permissions, because the target filesystem does not support it (primarily when writing to DOS FAT filesystems).

This function returns 0 on success or -1 on error.

(Added in 1.21.38)

guestfs_dd

 int
 guestfs_dd (guestfs_h *g,
             const char *src,
             const char *dest);

This function is deprecated. In new code, use the "guestfs_copy_device_to_device" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command copies from one source device or file src to another destination device or file dest. Normally you would use this to copy to or from a device or partition, for example to duplicate a filesystem.

If the destination is a device, it must be as large or larger than the source file or device, otherwise the copy will fail. This command cannot do partial copies (see guestfs_copy_device_to_device).

This function returns 0 on success or -1 on error.

(Added in 1.0.80)

guestfs_device_index

 int
 guestfs_device_index (guestfs_h *g,
                       const char *device);

This function takes a device name (eg. "/dev/sdb") and returns the index of the device in the list of devices.

Index numbers start from 0. The named device must exist, for example as a string returned from guestfs_list_devices.

See also guestfs_list_devices, guestfs_part_to_dev.

On error this function returns -1.

(Added in 1.19.7)

guestfs_df

 char *
 guestfs_df (guestfs_h *g);

This command runs the df command to report disk space used.

This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string. Use guestfs_statvfs from programs.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.54)

guestfs_df_h

 char *
 guestfs_df_h (guestfs_h *g);

This command runs the df -h command to report disk space used in human-readable format.

This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string. Use guestfs_statvfs from programs.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.54)

guestfs_disk_create

 int
 guestfs_disk_create (guestfs_h *g,
                      const char *filename,
                      const char *format,
                      int64_t size,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_DISK_CREATE_BACKINGFILE, const char *backingfile,
 GUESTFS_DISK_CREATE_BACKINGFORMAT, const char *backingformat,
 GUESTFS_DISK_CREATE_PREALLOCATION, const char *preallocation,
 GUESTFS_DISK_CREATE_COMPAT, const char *compat,
 GUESTFS_DISK_CREATE_CLUSTERSIZE, int clustersize,

Create a blank disk image called filename (a host file) with format format (usually raw or qcow2). The size is size bytes.

If used with the optional backingfile parameter, then a snapshot is created on top of the backing file. In this case, size must be passed as -1. The size of the snapshot is the same as the size of the backing file, which is discovered automatically. You are encouraged to also pass backingformat to describe the format of backingfile.

The other optional parameters are:

preallocation

If format is raw, then this can be either sparse or full to create a sparse or fully allocated file respectively. The default is sparse.

If format is qcow2, then this can be either off or metadata. Preallocating metadata can be faster when doing lots of writes, but uses more space. The default is off.

compat

qcow2 only: Pass the string 1.1 to use the advanced qcow2 format supported by qemu ≥ 1.1.

clustersize

qcow2 only: Change the qcow2 cluster size. The default is 65536 (bytes) and this setting may be any power of two between 512 and 2097152.

Note that this call does not add the new disk to the handle. You may need to call guestfs_add_drive_opts separately.

This function returns 0 on success or -1 on error.

(Added in 1.25.31)

guestfs_disk_create_va

 int
 guestfs_disk_create_va (guestfs_h *g,
                         const char *filename,
                         const char *format,
                         int64_t size,
                         va_list args);

This is the "va_list variant" of "guestfs_disk_create".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_disk_create_argv

 int
 guestfs_disk_create_argv (guestfs_h *g,
                           const char *filename,
                           const char *format,
                           int64_t size,
                           const struct guestfs_disk_create_argv *optargs);

This is the "argv variant" of "guestfs_disk_create".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_disk_format

 char *
 guestfs_disk_format (guestfs_h *g,
                      const char *filename);

Detect and return the format of the disk image called filename. filename can also be a host device, etc. If the format of the image could not be detected, then "unknown" is returned.

Note that detecting the disk format can be insecure under some circumstances. See "CVE-2010-3851" in guestfs(3).

See also: "DISK IMAGE FORMATS" in guestfs(3)

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.38)

guestfs_disk_has_backing_file

 int
 guestfs_disk_has_backing_file (guestfs_h *g,
                                const char *filename);

Detect and return whether the disk image filename has a backing file.

Note that detecting disk features can be insecure under some circumstances. See "CVE-2010-3851" in guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.19.39)

guestfs_disk_virtual_size

 int64_t
 guestfs_disk_virtual_size (guestfs_h *g,
                            const char *filename);

Detect and return the virtual size in bytes of the disk image called filename.

Note that detecting disk features can be insecure under some circumstances. See "CVE-2010-3851" in guestfs(3).

On error this function returns -1.

(Added in 1.19.39)

guestfs_dmesg

 char *
 guestfs_dmesg (guestfs_h *g);

This returns the kernel messages (dmesg output) from the guest kernel. This is sometimes useful for extended debugging of problems.

Another way to get the same information is to enable verbose messages with guestfs_set_verbose or by setting the environment variable LIBGUESTFS_DEBUG=1 before running the program.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.18)

guestfs_download

 int
 guestfs_download (guestfs_h *g,
                   const char *remotefilename,
                   const char *filename);

Download file remotefilename and save it as filename on the local machine.

filename can also be a named pipe.

See also guestfs_upload, guestfs_cat.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.0.2)

guestfs_download_offset

 int
 guestfs_download_offset (guestfs_h *g,
                          const char *remotefilename,
                          const char *filename,
                          int64_t offset,
                          int64_t size);

Download file remotefilename and save it as filename on the local machine.

remotefilename is read for size bytes starting at offset (this region must be within the file or device).

Note that there is no limit on the amount of data that can be downloaded with this call, unlike with guestfs_pread, and this call always reads the full amount unless an error occurs.

See also guestfs_download, guestfs_pread.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.5.17)

guestfs_drop_caches

 int
 guestfs_drop_caches (guestfs_h *g,
                      int whattodrop);

This instructs the guest kernel to drop its page cache, and/or dentries and inode caches. The parameter whattodrop tells the kernel what precisely to drop, see http://linux-mm.org/Drop_Caches

Setting whattodrop to 3 should drop everything.

This automatically calls sync(2) before the operation, so that the maximum guest memory is freed.

This function returns 0 on success or -1 on error.

(Added in 1.0.18)

guestfs_du

 int64_t
 guestfs_du (guestfs_h *g,
             const char *path);

This command runs the du -s command to estimate file space usage for path.

path can be a file or a directory. If path is a directory then the estimate includes the contents of the directory and all subdirectories (recursively).

The result is the estimated size in kilobytes (ie. units of 1024 bytes).

On error this function returns -1.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.0.54)

guestfs_e2fsck

 int
 guestfs_e2fsck (guestfs_h *g,
                 const char *device,
                 ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_E2FSCK_CORRECT, int correct,
 GUESTFS_E2FSCK_FORCEALL, int forceall,

This runs the ext2/ext3 filesystem checker on device. It can take the following optional arguments:

correct

Automatically repair the file system. This option will cause e2fsck to automatically fix any filesystem problems that can be safely fixed without human intervention.

This option may not be specified at the same time as the forceall option.

forceall

Assume an answer of 'yes' to all questions; allows e2fsck to be used non-interactively.

This option may not be specified at the same time as the correct option.

This function returns 0 on success or -1 on error.

(Added in 1.15.17)

guestfs_e2fsck_va

 int
 guestfs_e2fsck_va (guestfs_h *g,
                    const char *device,
                    va_list args);

This is the "va_list variant" of "guestfs_e2fsck".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_e2fsck_argv

 int
 guestfs_e2fsck_argv (guestfs_h *g,
                      const char *device,
                      const struct guestfs_e2fsck_argv *optargs);

This is the "argv variant" of "guestfs_e2fsck".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_e2fsck_f

 int
 guestfs_e2fsck_f (guestfs_h *g,
                   const char *device);

This function is deprecated. In new code, use the "guestfs_e2fsck" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This runs e2fsck -p -f device, ie. runs the ext2/ext3 filesystem checker on device, noninteractively (-p), even if the filesystem appears to be clean (-f).

This function returns 0 on success or -1 on error.

(Added in 1.0.29)

guestfs_echo_daemon

 char *
 guestfs_echo_daemon (guestfs_h *g,
                      char *const *words);

This command concatenates the list of words passed with single spaces between them and returns the resulting string.

You can use this command to test the connection through to the daemon.

See also guestfs_ping_daemon.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.69)

guestfs_egrep

 char **
 guestfs_egrep (guestfs_h *g,
                const char *regex,
                const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external egrep program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_egrepi

 char **
 guestfs_egrepi (guestfs_h *g,
                 const char *regex,
                 const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external egrep -i program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_equal

 int
 guestfs_equal (guestfs_h *g,
                const char *file1,
                const char *file2);

This compares the two files file1 and file2 and returns true if their content is exactly equal, or false otherwise.

The external cmp(1) program is used for the comparison.

This function returns a C truth value on success or -1 on error.

(Added in 1.0.18)

guestfs_exists

 int
 guestfs_exists (guestfs_h *g,
                 const char *path);

This returns true if and only if there is a file, directory (or anything) with the given path name.

See also guestfs_is_file, guestfs_is_dir, guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 0.8)

guestfs_extlinux

 int
 guestfs_extlinux (guestfs_h *g,
                   const char *directory);

Install the SYSLINUX bootloader on the device mounted at directory. Unlike guestfs_syslinux which requires a FAT filesystem, this can be used on an ext2/3/4 or btrfs filesystem.

The directory parameter can be either a mountpoint, or a directory within the mountpoint.

You also have to mark the partition as "active" (guestfs_part_set_bootable) and a Master Boot Record must be installed (eg. using guestfs_pwrite_device) on the first sector of the whole disk. The SYSLINUX package comes with some suitable Master Boot Records. See the extlinux(1) man page for further information.

Additional configuration can be supplied to SYSLINUX by placing a file called extlinux.conf on the filesystem under directory. For further information about the contents of this file, see extlinux(1).

See also guestfs_syslinux.

This function returns 0 on success or -1 on error.

(Added in 1.21.27)

guestfs_fallocate

 int
 guestfs_fallocate (guestfs_h *g,
                    const char *path,
                    int len);

This function is deprecated. In new code, use the "guestfs_fallocate64" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command preallocates a file (containing zero bytes) named path of size len bytes. If the file exists already, it is overwritten.

Do not confuse this with the guestfish-specific alloc command which allocates a file in the host and attaches it as a device.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_fallocate64

 int
 guestfs_fallocate64 (guestfs_h *g,
                      const char *path,
                      int64_t len);

This command preallocates a file (containing zero bytes) named path of size len bytes. If the file exists already, it is overwritten.

Note that this call allocates disk blocks for the file. To create a sparse file use guestfs_truncate_size instead.

The deprecated call guestfs_fallocate does the same, but owing to an oversight it only allowed 30 bit lengths to be specified, effectively limiting the maximum size of files created through that call to 1GB.

Do not confuse this with the guestfish-specific alloc and sparse commands which create a file in the host and attach it as a device.

This function returns 0 on success or -1 on error.

(Added in 1.3.17)

guestfs_feature_available

 int
 guestfs_feature_available (guestfs_h *g,
                            char *const *groups);

This is the same as guestfs_available, but unlike that call it returns a simple true/false boolean result, instead of throwing an exception if a feature is not found. For other documentation see guestfs_available.

This function returns a C truth value on success or -1 on error.

(Added in 1.21.26)

guestfs_fgrep

 char **
 guestfs_fgrep (guestfs_h *g,
                const char *pattern,
                const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external fgrep program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_fgrepi

 char **
 guestfs_fgrepi (guestfs_h *g,
                 const char *pattern,
                 const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external fgrep -i program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_file

 char *
 guestfs_file (guestfs_h *g,
               const char *path);

This call uses the standard file(1) command to determine the type or contents of the file.

This call will also transparently look inside various types of compressed file.

The exact command which runs is file -zb path. Note in particular that the filename is not prepended to the output (the -b option).

The output depends on the output of the underlying file(1) command and it can change in future in ways beyond our control. In other words, the output is not guaranteed by the ABI.

See also: file(1), guestfs_vfs_type, guestfs_lstat, guestfs_is_file, guestfs_is_blockdev (etc), guestfs_is_zero.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 0.9.1)

guestfs_file_architecture

 char *
 guestfs_file_architecture (guestfs_h *g,
                            const char *filename);

This detects the architecture of the binary filename, and returns it if known.

Currently defined architectures are:

"i386"

This string is returned for all 32 bit i386, i486, i586, i686 binaries irrespective of the precise processor requirements of the binary.

"x86_64"

64 bit x86-64.

"sparc"

32 bit SPARC.

"sparc64"

64 bit SPARC V9 and above.

"ia64"

Intel Itanium.

"ppc"

32 bit Power PC.

"ppc64"

64 bit Power PC.

Libguestfs may return other architecture strings in future.

The function works on at least the following types of files:

What it can't do currently:

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_filesize

 int64_t
 guestfs_filesize (guestfs_h *g,
                   const char *file);

This command returns the size of file in bytes.

To get other stats about a file, use guestfs_stat, guestfs_lstat, guestfs_is_dir, guestfs_is_file etc. To get the size of block devices, use guestfs_blockdev_getsize64.

On error this function returns -1.

(Added in 1.0.82)

guestfs_filesystem_available

 int
 guestfs_filesystem_available (guestfs_h *g,
                               const char *filesystem);

Check whether libguestfs supports the named filesystem. The argument filesystem is a filesystem name, such as ext3.

You must call guestfs_launch before using this command.

This is mainly useful as a negative test. If this returns true, it doesn't mean that a particular filesystem can be created or mounted, since filesystems can fail for other reasons such as it being a later version of the filesystem, or having incompatible features, or lacking the right mkfs.<fs> tool.

See also guestfs_available, guestfs_feature_available, "AVAILABILITY" in guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.19.5)

guestfs_fill

 int
 guestfs_fill (guestfs_h *g,
               int c,
               int len,
               const char *path);

This command creates a new file called path. The initial content of the file is len octets of c, where c must be a number in the range [0..255].

To fill a file with zero bytes (sparsely), it is much more efficient to use guestfs_truncate_size. To create a file with a pattern of repeating bytes use guestfs_fill_pattern.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.0.79)

guestfs_fill_dir

 int
 guestfs_fill_dir (guestfs_h *g,
                   const char *dir,
                   int nr);

This function, useful for testing filesystems, creates nr empty files in the directory dir with names 00000000 through nr-1 (ie. each file name is 8 digits long padded with zeroes).

This function returns 0 on success or -1 on error.

(Added in 1.19.32)

guestfs_fill_pattern

 int
 guestfs_fill_pattern (guestfs_h *g,
                       const char *pattern,
                       int len,
                       const char *path);

This function is like guestfs_fill except that it creates a new file of length len containing the repeating pattern of bytes in pattern. The pattern is truncated if necessary to ensure the length of the file is exactly len bytes.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.3.12)

guestfs_find

 char **
 guestfs_find (guestfs_h *g,
               const char *directory);

This command lists out all files and directories, recursively, starting at directory. It is essentially equivalent to running the shell command find directory -print but some post-processing happens on the output, described below.

This returns a list of strings without any prefix. Thus if the directory structure was:

 /tmp/a
 /tmp/b
 /tmp/c/d

then the returned list from guestfs_find /tmp would be 4 elements:

 a
 b
 c
 c/d

If directory is not a directory, then this command returns an error.

The returned list is sorted.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.27)

guestfs_find0

 int
 guestfs_find0 (guestfs_h *g,
                const char *directory,
                const char *files);

This command lists out all files and directories, recursively, starting at directory, placing the resulting list in the external file called files.

This command works the same way as guestfs_find with the following exceptions:

This function returns 0 on success or -1 on error.

(Added in 1.0.74)

guestfs_findfs_label

 char *
 guestfs_findfs_label (guestfs_h *g,
                       const char *label);

This command searches the filesystems and returns the one which has the given label. An error is returned if no such filesystem can be found.

To find the label of a filesystem, use guestfs_vfs_label.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_findfs_uuid

 char *
 guestfs_findfs_uuid (guestfs_h *g,
                      const char *uuid);

This command searches the filesystems and returns the one which has the given UUID. An error is returned if no such filesystem can be found.

To find the UUID of a filesystem, use guestfs_vfs_uuid.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_fsck

 int
 guestfs_fsck (guestfs_h *g,
               const char *fstype,
               const char *device);

This runs the filesystem checker (fsck) on device which should have filesystem type fstype.

The returned integer is the status. See fsck(8) for the list of status codes from fsck.

Notes:

This command is entirely equivalent to running fsck -a -t fstype device.

On error this function returns -1.

(Added in 1.0.16)

guestfs_fstrim

 int
 guestfs_fstrim (guestfs_h *g,
                 const char *mountpoint,
                 ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_FSTRIM_OFFSET, int64_t offset,
 GUESTFS_FSTRIM_LENGTH, int64_t length,
 GUESTFS_FSTRIM_MINIMUMFREEEXTENT, int64_t minimumfreeextent,

Trim the free space in the filesystem mounted on mountpoint. The filesystem must be mounted read-write.

The filesystem contents are not affected, but any free space in the filesystem is "trimmed", that is, given back to the host device, thus making disk images more sparse, allowing unused space in qcow2 files to be reused, etc.

This operation requires support in libguestfs, the mounted filesystem, the host filesystem, qemu and the host kernel. If this support isn't present it may give an error or even appear to run but do nothing.

See also guestfs_zero_free_space. That is a slightly different operation that turns free space in the filesystem into zeroes. It is valid to call guestfs_fstrim either instead of, or after calling guestfs_zero_free_space.

This function returns 0 on success or -1 on error.

(Added in 1.19.6)

guestfs_fstrim_va

 int
 guestfs_fstrim_va (guestfs_h *g,
                    const char *mountpoint,
                    va_list args);

This is the "va_list variant" of "guestfs_fstrim".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_fstrim_argv

 int
 guestfs_fstrim_argv (guestfs_h *g,
                      const char *mountpoint,
                      const struct guestfs_fstrim_argv *optargs);

This is the "argv variant" of "guestfs_fstrim".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_get_append

 const char *
 guestfs_get_append (guestfs_h *g);

Return the additional kernel options which are added to the guest kernel command line.

If NULL then no options are added.

This function returns a string which may be NULL. There is no way to return an error from this function. The string is owned by the guest handle and must not be freed.

(Added in 1.0.26)

guestfs_get_attach_method

 char *
 guestfs_get_attach_method (guestfs_h *g);

This function is deprecated. In new code, use the "guestfs_get_backend" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Return the current backend.

See guestfs_set_backend and "BACKEND" in guestfs(3).

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.9.8)

guestfs_get_autosync

 int
 guestfs_get_autosync (guestfs_h *g);

Get the autosync flag.

This function returns a C truth value on success or -1 on error.

(Added in 0.3)

guestfs_get_backend

 char *
 guestfs_get_backend (guestfs_h *g);

Return the current backend.

This handle property was previously called the "attach method".

See guestfs_set_backend and "BACKEND" in guestfs(3).

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.21.26)

guestfs_get_backend_setting

 char *
 guestfs_get_backend_setting (guestfs_h *g,
                              const char *name);

Find a backend setting string which is either "name" or begins with "name=". If "name", this returns the string "1". If "name=", this returns the part after the equals sign (which may be an empty string).

If no such setting is found, this function throws an error. The errno (see guestfs_last_errno) will be ESRCH in this case.

See "BACKEND" in guestfs(3), "BACKEND SETTINGS" in guestfs(3).

This function returns a string, or NULL on error. The caller must free the returned string after use.

guestfs_get_backend_settings

 char **
 guestfs_get_backend_settings (guestfs_h *g);

Return the current backend settings.

This call returns all backend settings strings. If you want to find a single backend setting, see guestfs_get_backend_setting.

See "BACKEND" in guestfs(3), "BACKEND SETTINGS" in guestfs(3).

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.25.24)

guestfs_get_cachedir

 char *
 guestfs_get_cachedir (guestfs_h *g);

Get the directory used by the handle to store the appliance cache.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.58)

guestfs_get_direct

 int
 guestfs_get_direct (guestfs_h *g);

Return the direct appliance mode flag.

This function returns a C truth value on success or -1 on error.

(Added in 1.0.72)

guestfs_get_e2attrs

 char *
 guestfs_get_e2attrs (guestfs_h *g,
                      const char *file);

This returns the file attributes associated with file.

The attributes are a set of bits associated with each inode which affect the behaviour of the file. The attributes are returned as a string of letters (described below). The string may be empty, indicating that no file attributes are set for this file.

These attributes are only present when the file is located on an ext2/3/4 filesystem. Using this call on other filesystem types will result in an error.

The characters (file attributes) in the returned string are currently:

'A'

When the file is accessed, its atime is not modified.

'a'

The file is append-only.

'c'

The file is compressed on-disk.

'D'

(Directories only.) Changes to this directory are written synchronously to disk.

'd'

The file is not a candidate for backup (see dump(8)).

'E'

The file has compression errors.

'e'

The file is using extents.

'h'

The file is storing its blocks in units of the filesystem blocksize instead of sectors.

'I'

(Directories only.) The directory is using hashed trees.

'i'

The file is immutable. It cannot be modified, deleted or renamed. No link can be created to this file.

'j'

The file is data-journaled.

's'

When the file is deleted, all its blocks will be zeroed.

'S'

Changes to this file are written synchronously to disk.

'T'

(Directories only.) This is a hint to the block allocator that subdirectories contained in this directory should be spread across blocks. If not present, the block allocator will try to group subdirectories together.

't'

For a file, this disables tail-merging. (Not used by upstream implementations of ext2.)

'u'

When the file is deleted, its blocks will be saved, allowing the file to be undeleted.

'X'

The raw contents of the compressed file may be accessed.

'Z'

The compressed file is dirty.

More file attributes may be added to this list later. Not all file attributes may be set for all kinds of files. For detailed information, consult the chattr(1) man page.

See also guestfs_set_e2attrs.

Don't confuse these attributes with extended attributes (see guestfs_getxattr).

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.17.31)

guestfs_get_e2generation

 int64_t
 guestfs_get_e2generation (guestfs_h *g,
                           const char *file);

This returns the ext2 file generation of a file. The generation (which used to be called the "version") is a number associated with an inode. This is most commonly used by NFS servers.

The generation is only present when the file is located on an ext2/3/4 filesystem. Using this call on other filesystem types will result in an error.

See guestfs_set_e2generation.

On error this function returns -1.

(Added in 1.17.31)

guestfs_get_e2label

 char *
 guestfs_get_e2label (guestfs_h *g,
                      const char *device);

This function is deprecated. In new code, use the "guestfs_vfs_label" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This returns the ext2/3/4 filesystem label of the filesystem on device.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.15)

guestfs_get_e2uuid

 char *
 guestfs_get_e2uuid (guestfs_h *g,
                     const char *device);

This function is deprecated. In new code, use the "guestfs_vfs_uuid" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This returns the ext2/3/4 filesystem UUID of the filesystem on device.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.15)

guestfs_get_hv

 char *
 guestfs_get_hv (guestfs_h *g);

Return the current hypervisor binary.

This is always non-NULL. If it wasn't set already, then this will return the default qemu binary name.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.23.17)

guestfs_get_libvirt_requested_credential_challenge

 char *
 guestfs_get_libvirt_requested_credential_challenge (guestfs_h *g,
                                                     int index);

Get the challenge (provided by libvirt) for the index'th requested credential. If libvirt did not provide a challenge, this returns the empty string "".

See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.52)

guestfs_get_libvirt_requested_credential_defresult

 char *
 guestfs_get_libvirt_requested_credential_defresult (guestfs_h *g,
                                                     int index);

Get the default result (provided by libvirt) for the index'th requested credential. If libvirt did not provide a default result, this returns the empty string "".

See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.52)

guestfs_get_libvirt_requested_credential_prompt

 char *
 guestfs_get_libvirt_requested_credential_prompt (guestfs_h *g,
                                                  int index);

Get the prompt (provided by libvirt) for the index'th requested credential. If libvirt did not provide a prompt, this returns the empty string "".

See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.52)

guestfs_get_libvirt_requested_credentials

 char **
 guestfs_get_libvirt_requested_credentials (guestfs_h *g);

This should only be called during the event callback for events of type GUESTFS_EVENT_LIBVIRT_AUTH.

Return the list of credentials requested by libvirt. Possible values are a subset of the strings provided when you called guestfs_set_libvirt_supported_credentials.

See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.19.52)

guestfs_get_memsize

 int
 guestfs_get_memsize (guestfs_h *g);

This gets the memory size in megabytes allocated to the hypervisor.

If guestfs_set_memsize was not called on this handle, and if LIBGUESTFS_MEMSIZE was not set, then this returns the compiled-in default value for memsize.

For more information on the architecture of libguestfs, see guestfs(3).

On error this function returns -1.

(Added in 1.0.55)

guestfs_get_network

 int
 guestfs_get_network (guestfs_h *g);

This returns the enable network flag.

This function returns a C truth value on success or -1 on error.

(Added in 1.5.4)

guestfs_get_path

 const char *
 guestfs_get_path (guestfs_h *g);

Return the current search path.

This is always non-NULL. If it wasn't set already, then this will return the default path.

This function returns a string, or NULL on error. The string is owned by the guest handle and must not be freed.

(Added in 0.3)

guestfs_get_pgroup

 int
 guestfs_get_pgroup (guestfs_h *g);

This returns the process group flag.

This function returns a C truth value on success or -1 on error.

(Added in 1.11.18)

guestfs_get_pid

 int
 guestfs_get_pid (guestfs_h *g);

Return the process ID of the hypervisor. If there is no hypervisor running, then this will return an error.

This is an internal call used for debugging and testing.

On error this function returns -1.

(Added in 1.0.56)

guestfs_get_program

 const char *
 guestfs_get_program (guestfs_h *g);

Get the program name. See guestfs_set_program.

This function returns a string, or NULL on error. The string is owned by the guest handle and must not be freed.

(Added in 1.21.29)

guestfs_get_qemu

 const char *
 guestfs_get_qemu (guestfs_h *g);

This function is deprecated. In new code, use the "guestfs_get_hv" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Return the current hypervisor binary (usually qemu).

This is always non-NULL. If it wasn't set already, then this will return the default qemu binary name.

This function returns a string, or NULL on error. The string is owned by the guest handle and must not be freed.

(Added in 1.0.6)

guestfs_get_recovery_proc

 int
 guestfs_get_recovery_proc (guestfs_h *g);

Return the recovery process enabled flag.

This function returns a C truth value on success or -1 on error.

(Added in 1.0.77)

guestfs_get_selinux

 int
 guestfs_get_selinux (guestfs_h *g);

This returns the current setting of the selinux flag which is passed to the appliance at boot time. See guestfs_set_selinux.

For more information on the architecture of libguestfs, see guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.0.67)

guestfs_get_smp

 int
 guestfs_get_smp (guestfs_h *g);

This returns the number of virtual CPUs assigned to the appliance.

On error this function returns -1.

(Added in 1.13.15)

guestfs_get_state

 int
 guestfs_get_state (guestfs_h *g);

This returns the current state as an opaque integer. This is only useful for printing debug and internal error messages.

For more information on states, see guestfs(3).

On error this function returns -1.

(Added in 1.0.2)

guestfs_get_tmpdir

 char *
 guestfs_get_tmpdir (guestfs_h *g);

Get the directory used by the handle to store temporary files.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.58)

guestfs_get_trace

 int
 guestfs_get_trace (guestfs_h *g);

Return the command trace flag.

This function returns a C truth value on success or -1 on error.

(Added in 1.0.69)

guestfs_get_umask

 int
 guestfs_get_umask (guestfs_h *g);

Return the current umask. By default the umask is 022 unless it has been set by calling guestfs_umask.

On error this function returns -1.

(Added in 1.3.4)

guestfs_get_verbose

 int
 guestfs_get_verbose (guestfs_h *g);

This returns the verbose messages flag.

This function returns a C truth value on success or -1 on error.

(Added in 0.3)

guestfs_getcon

 char *
 guestfs_getcon (guestfs_h *g);

This gets the SELinux security context of the daemon.

See the documentation about SELINUX in guestfs(3), and guestfs_setcon

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.67)

guestfs_getxattr

 char *
 guestfs_getxattr (guestfs_h *g,
                   const char *path,
                   const char *name,
                   size_t *size_r);

Get a single extended attribute from file path named name. This call follows symlinks. If you want to lookup an extended attribute for the symlink itself, use guestfs_lgetxattr.

Normally it is better to get all extended attributes from a file in one go by calling guestfs_getxattrs. However some Linux filesystem implementations are buggy and do not provide a way to list out attributes. For these filesystems (notably ntfs-3g) you have to know the names of the extended attributes you want in advance and call this function.

Extended attribute values are blobs of binary data. If there is no extended attribute named name, this returns an error.

See also: guestfs_getxattrs, guestfs_lgetxattr, attr(5).

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

(Added in 1.7.24)

guestfs_getxattrs

 struct guestfs_xattr_list *
 guestfs_getxattrs (guestfs_h *g,
                    const char *path);

This call lists the extended attributes of the file or directory path.

At the system call level, this is a combination of the listxattr(2) and getxattr(2) calls.

See also: guestfs_lgetxattrs, attr(5).

This function returns a struct guestfs_xattr_list *, or NULL if there was an error. The caller must call guestfs_free_xattr_list after use.

(Added in 1.0.59)

guestfs_glob_expand

 char **
 guestfs_glob_expand (guestfs_h *g,
                      const char *pattern);

This command searches for all the pathnames matching pattern according to the wildcard expansion rules used by the shell.

If no paths match, then this returns an empty list (note: not an error).

It is just a wrapper around the C glob(3) function with flags GLOB_MARK|GLOB_BRACE. See that manual page for more details.

Notice that there is no equivalent command for expanding a device name (eg. /dev/sd*). Use guestfs_list_devices, guestfs_list_partitions etc functions instead.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.50)

guestfs_grep

 char **
 guestfs_grep (guestfs_h *g,
               const char *regex,
               const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_grep_opts" with no optional arguments.

(Added in 1.0.66)

guestfs_grep_opts

 char **
 guestfs_grep_opts (guestfs_h *g,
                    const char *regex,
                    const char *path,
                    ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_GREP_OPTS_EXTENDED, int extended,
 GUESTFS_GREP_OPTS_FIXED, int fixed,
 GUESTFS_GREP_OPTS_INSENSITIVE, int insensitive,
 GUESTFS_GREP_OPTS_COMPRESSED, int compressed,

This calls the external grep program and returns the matching lines.

The optional flags are:

extended

Use extended regular expressions. This is the same as using the -E flag.

fixed

Match fixed (don't use regular expressions). This is the same as using the -F flag.

insensitive

Match case-insensitive. This is the same as using the -i flag.

compressed

Use zgrep instead of grep. This allows the input to be compress- or gzip-compressed.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.19.28)

guestfs_grep_opts_va

 char **
 guestfs_grep_opts_va (guestfs_h *g,
                       const char *regex,
                       const char *path,
                       va_list args);

This is the "va_list variant" of "guestfs_grep_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_grep_opts_argv

 char **
 guestfs_grep_opts_argv (guestfs_h *g,
                         const char *regex,
                         const char *path,
                         const struct guestfs_grep_opts_argv *optargs);

This is the "argv variant" of "guestfs_grep_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_grepi

 char **
 guestfs_grepi (guestfs_h *g,
                const char *regex,
                const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external grep -i program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_grub_install

 int
 guestfs_grub_install (guestfs_h *g,
                       const char *root,
                       const char *device);

This command installs GRUB 1 (the Grand Unified Bootloader) on device, with the root directory being root.

Notes:

This function returns 0 on success or -1 on error.

(Added in 1.0.17)

guestfs_head

 char **
 guestfs_head (guestfs_h *g,
               const char *path);

This command returns up to the first 10 lines of a file as a list of strings.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.54)

guestfs_head_n

 char **
 guestfs_head_n (guestfs_h *g,
                 int nrlines,
                 const char *path);

If the parameter nrlines is a positive number, this returns the first nrlines lines of the file path.

If the parameter nrlines is a negative number, this returns lines from the file path, excluding the last nrlines lines.

If the parameter nrlines is zero, this returns an empty list.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.54)

guestfs_hexdump

 char *
 guestfs_hexdump (guestfs_h *g,
                  const char *path);

This runs hexdump -C on the given path. The result is the human-readable, canonical hex dump of the file.

This function returns a string, or NULL on error. The caller must free the returned string after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.22)

guestfs_hivex_close

 int
 guestfs_hivex_close (guestfs_h *g);

Close the current hivex handle.

This is a wrapper around the hivex(3) call of the same name.

This function returns 0 on success or -1 on error.

(Added in 1.19.35)

guestfs_hivex_commit

 int
 guestfs_hivex_commit (guestfs_h *g,
                       const char *filename);

Commit (write) changes to the hive.

If the optional filename parameter is null, then the changes are written back to the same hive that was opened. If this is not null then they are written to the alternate filename given and the original hive is left untouched.

This is a wrapper around the hivex(3) call of the same name.

This function returns 0 on success or -1 on error.

(Added in 1.19.35)

guestfs_hivex_node_add_child

 int64_t
 guestfs_hivex_node_add_child (guestfs_h *g,
                               int64_t parent,
                               const char *name);

Add a child node to parent named name.

This is a wrapper around the hivex(3) call of the same name.

On error this function returns -1.

(Added in 1.19.35)

guestfs_hivex_node_children

 struct guestfs_hivex_node_list *
 guestfs_hivex_node_children (guestfs_h *g,
                              int64_t nodeh);

Return the list of nodes which are subkeys of nodeh.

This is a wrapper around the hivex(3) call of the same name.

This function returns a struct guestfs_hivex_node_list *, or NULL if there was an error. The caller must call guestfs_free_hivex_node_list after use.

(Added in 1.19.35)

guestfs_hivex_node_delete_child

 int
 guestfs_hivex_node_delete_child (guestfs_h *g,
                                  int64_t nodeh);

Delete nodeh, recursively if necessary.

This is a wrapper around the hivex(3) call of the same name.

This function returns 0 on success or -1 on error.

(Added in 1.19.35)

guestfs_hivex_node_get_child

 int64_t
 guestfs_hivex_node_get_child (guestfs_h *g,
                               int64_t nodeh,
                               const char *name);

Return the child of nodeh with the name name, if it exists. This can return 0 meaning the name was not found.

This is a wrapper around the hivex(3) call of the same name.

On error this function returns -1.

(Added in 1.19.35)

guestfs_hivex_node_get_value

 int64_t
 guestfs_hivex_node_get_value (guestfs_h *g,
                               int64_t nodeh,
                               const char *key);

Return the value attached to nodeh which has the name key, if it exists. This can return 0 meaning the key was not found.

This is a wrapper around the hivex(3) call of the same name.

On error this function returns -1.

(Added in 1.19.35)

guestfs_hivex_node_name

 char *
 guestfs_hivex_node_name (guestfs_h *g,
                          int64_t nodeh);

Return the name of nodeh.

This is a wrapper around the hivex(3) call of the same name.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.35)

guestfs_hivex_node_parent

 int64_t
 guestfs_hivex_node_parent (guestfs_h *g,
                            int64_t nodeh);

Return the parent node of nodeh.

This is a wrapper around the hivex(3) call of the same name.

On error this function returns -1.

(Added in 1.19.35)

guestfs_hivex_node_set_value

 int
 guestfs_hivex_node_set_value (guestfs_h *g,
                               int64_t nodeh,
                               const char *key,
                               int64_t t,
                               const char *val,
                               size_t val_size);

Set or replace a single value under the node nodeh. The key is the name, t is the type, and val is the data.

This is a wrapper around the hivex(3) call of the same name.

This function returns 0 on success or -1 on error.

(Added in 1.19.35)

guestfs_hivex_node_values

 struct guestfs_hivex_value_list *
 guestfs_hivex_node_values (guestfs_h *g,
                            int64_t nodeh);

Return the array of (key, datatype, data) tuples attached to nodeh.

This is a wrapper around the hivex(3) call of the same name.

This function returns a struct guestfs_hivex_value_list *, or NULL if there was an error. The caller must call guestfs_free_hivex_value_list after use.

(Added in 1.19.35)

guestfs_hivex_open

 int
 guestfs_hivex_open (guestfs_h *g,
                     const char *filename,
                     ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_HIVEX_OPEN_VERBOSE, int verbose,
 GUESTFS_HIVEX_OPEN_DEBUG, int debug,
 GUESTFS_HIVEX_OPEN_WRITE, int write,

Open the Windows Registry hive file named filename. If there was any previous hivex handle associated with this guestfs session, then it is closed.

This is a wrapper around the hivex(3) call of the same name.

This function returns 0 on success or -1 on error.

(Added in 1.19.35)

guestfs_hivex_open_va

 int
 guestfs_hivex_open_va (guestfs_h *g,
                        const char *filename,
                        va_list args);

This is the "va_list variant" of "guestfs_hivex_open".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_hivex_open_argv

 int
 guestfs_hivex_open_argv (guestfs_h *g,
                          const char *filename,
                          const struct guestfs_hivex_open_argv *optargs);

This is the "argv variant" of "guestfs_hivex_open".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_hivex_root

 int64_t
 guestfs_hivex_root (guestfs_h *g);

Return the root node of the hive.

This is a wrapper around the hivex(3) call of the same name.

On error this function returns -1.

(Added in 1.19.35)

guestfs_hivex_value_key

 char *
 guestfs_hivex_value_key (guestfs_h *g,
                          int64_t valueh);

Return the key (name) field of a (key, datatype, data) tuple.

This is a wrapper around the hivex(3) call of the same name.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.35)

guestfs_hivex_value_type

 int64_t
 guestfs_hivex_value_type (guestfs_h *g,
                           int64_t valueh);

Return the data type field from a (key, datatype, data) tuple.

This is a wrapper around the hivex(3) call of the same name.

On error this function returns -1.

(Added in 1.19.35)

guestfs_hivex_value_utf8

 char *
 guestfs_hivex_value_utf8 (guestfs_h *g,
                           int64_t valueh);

This calls guestfs_hivex_value_value (which returns the data field from a hivex value tuple). It then assumes that the field is a UTF-16LE string and converts the result to UTF-8 (or if this is not possible, it returns an error).

This is useful for reading strings out of the Windows registry. However it is not foolproof because the registry is not strongly-typed and fields can contain arbitrary or unexpected data.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.35)

guestfs_hivex_value_value

 char *
 guestfs_hivex_value_value (guestfs_h *g,
                            int64_t valueh,
                            size_t *size_r);

Return the data field of a (key, datatype, data) tuple.

This is a wrapper around the hivex(3) call of the same name.

See also: guestfs_hivex_value_utf8.

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

(Added in 1.19.35)

guestfs_initrd_cat

 char *
 guestfs_initrd_cat (guestfs_h *g,
                     const char *initrdpath,
                     const char *filename,
                     size_t *size_r);

This command unpacks the file filename from the initrd file called initrdpath. The filename must be given without the initial / character.

For example, in guestfish you could use the following command to examine the boot script (usually called /init) contained in a Linux initrd or initramfs image:

 initrd-cat /boot/initrd-<version>.img init

See also guestfs_initrd_list.

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.84)

guestfs_initrd_list

 char **
 guestfs_initrd_list (guestfs_h *g,
                      const char *path);

This command lists out files contained in an initrd.

The files are listed without any initial / character. The files are listed in the order they appear (not necessarily alphabetical). Directory names are listed as separate items.

Old Linux kernels (2.4 and earlier) used a compressed ext2 filesystem as initrd. We only support the newer initramfs format (compressed cpio files).

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.54)

guestfs_inotify_add_watch

 int64_t
 guestfs_inotify_add_watch (guestfs_h *g,
                            const char *path,
                            int mask);

Watch path for the events listed in mask.

Note that if path is a directory then events within that directory are watched, but this does not happen recursively (in subdirectories).

Note for non-C or non-Linux callers: the inotify events are defined by the Linux kernel ABI and are listed in /usr/include/sys/inotify.h.

On error this function returns -1.

(Added in 1.0.66)

guestfs_inotify_close

 int
 guestfs_inotify_close (guestfs_h *g);

This closes the inotify handle which was previously opened by inotify_init. It removes all watches, throws away any pending events, and deallocates all resources.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_inotify_files

 char **
 guestfs_inotify_files (guestfs_h *g);

This function is a helpful wrapper around guestfs_inotify_read which just returns a list of pathnames of objects that were touched. The returned pathnames are sorted and deduplicated.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.66)

guestfs_inotify_init

 int
 guestfs_inotify_init (guestfs_h *g,
                       int maxevents);

This command creates a new inotify handle. The inotify subsystem can be used to notify events which happen to objects in the guest filesystem.

maxevents is the maximum number of events which will be queued up between calls to guestfs_inotify_read or guestfs_inotify_files. If this is passed as 0, then the kernel (or previously set) default is used. For Linux 2.6.29 the default was 16384 events. Beyond this limit, the kernel throws away events, but records the fact that it threw them away by setting a flag IN_Q_OVERFLOW in the returned structure list (see guestfs_inotify_read).

Before any events are generated, you have to add some watches to the internal watch list. See: guestfs_inotify_add_watch and guestfs_inotify_rm_watch.

Queued up events should be read periodically by calling guestfs_inotify_read (or guestfs_inotify_files which is just a helpful wrapper around guestfs_inotify_read). If you don't read the events out often enough then you risk the internal queue overflowing.

The handle should be closed after use by calling guestfs_inotify_close. This also removes any watches automatically.

See also inotify(7) for an overview of the inotify interface as exposed by the Linux kernel, which is roughly what we expose via libguestfs. Note that there is one global inotify handle per libguestfs instance.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_inotify_read

 struct guestfs_inotify_event_list *
 guestfs_inotify_read (guestfs_h *g);

Return the complete queue of events that have happened since the previous read call.

If no events have happened, this returns an empty list.

Note: In order to make sure that all events have been read, you must call this function repeatedly until it returns an empty list. The reason is that the call will read events up to the maximum appliance-to-host message size and leave remaining events in the queue.

This function returns a struct guestfs_inotify_event_list *, or NULL if there was an error. The caller must call guestfs_free_inotify_event_list after use.

(Added in 1.0.66)

guestfs_inotify_rm_watch

 int
 guestfs_inotify_rm_watch (guestfs_h *g,
                           int wd);

Remove a previously defined inotify watch. See guestfs_inotify_add_watch.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_inspect_get_arch

 char *
 guestfs_inspect_get_arch (guestfs_h *g,
                           const char *root);

This returns the architecture of the inspected operating system. The possible return values are listed under guestfs_file_architecture.

If the architecture could not be determined, then the string unknown is returned.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_inspect_get_distro

 char *
 guestfs_inspect_get_distro (guestfs_h *g,
                             const char *root);

This returns the distro (distribution) of the inspected operating system.

Currently defined distros are:

"archlinux"

Arch Linux.

"buildroot"

Buildroot-derived distro, but not one we specifically recognize.

"centos"

CentOS.

"cirros"

Cirros.

"debian"

Debian.

"fedora"

Fedora.

"freedos"

FreeDOS.

"gentoo"

Gentoo.

"linuxmint"

Linux Mint.

"mageia"

Mageia.

"mandriva"

Mandriva.

"meego"

MeeGo.

"openbsd"

OpenBSD.

"opensuse"

OpenSUSE.

"pardus"

Pardus.

"redhat-based"

Some Red Hat-derived distro.

"rhel"

Red Hat Enterprise Linux.

"scientificlinux"

Scientific Linux.

"slackware"

Slackware.

"sles"

SuSE Linux Enterprise Server or Desktop.

"suse-based"

Some openSuSE-derived distro.

"ttylinux"

ttylinux.

"ubuntu"

Ubuntu.

"unknown"

The distro could not be determined.

"windows"

Windows does not have distributions. This string is returned if the OS type is Windows.

Future versions of libguestfs may return other strings here. The caller should be prepared to handle any string.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_inspect_get_drive_mappings

 char **
 guestfs_inspect_get_drive_mappings (guestfs_h *g,
                                     const char *root);

This call is useful for Windows which uses a primitive system of assigning drive letters (like "C:") to partitions. This inspection API examines the Windows Registry to find out how disks/partitions are mapped to drive letters, and returns a hash table as in the example below:

 C      =>     /dev/vda2
 E      =>     /dev/vdb1
 F      =>     /dev/vdc1

Note that keys are drive letters. For Windows, the key is case insensitive and just contains the drive letter, without the customary colon separator character.

In future we may support other operating systems that also used drive letters, but the keys for those might not be case insensitive and might be longer than 1 character. For example in OS-9, hard drives were named h0, h1 etc.

For Windows guests, currently only hard drive mappings are returned. Removable disks (eg. DVD-ROMs) are ignored.

For guests that do not use drive mappings, or if the drive mappings could not be determined, this returns an empty hash table.

Please read "INSPECTION" in guestfs(3) for more details. See also guestfs_inspect_get_mountpoints, guestfs_inspect_get_filesystems.

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.9.17)

guestfs_inspect_get_filesystems

 char **
 guestfs_inspect_get_filesystems (guestfs_h *g,
                                  const char *root);

This returns a list of all the filesystems that we think are associated with this operating system. This includes the root filesystem, other ordinary filesystems, and non-mounted devices like swap partitions.

In the case of a multi-boot virtual machine, it is possible for a filesystem to be shared between operating systems.

Please read "INSPECTION" in guestfs(3) for more details. See also guestfs_inspect_get_mountpoints.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.5.3)

guestfs_inspect_get_format

 char *
 guestfs_inspect_get_format (guestfs_h *g,
                             const char *root);

This returns the format of the inspected operating system. You can use it to detect install images, live CDs and similar.

Currently defined formats are:

"installed"

This is an installed operating system.

"installer"

The disk image being inspected is not an installed operating system, but a bootable install disk, live CD, or similar.

"unknown"

The format of this disk image is not known.

Future versions of libguestfs may return other strings here. The caller should be prepared to handle any string.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.9.4)

guestfs_inspect_get_hostname

 char *
 guestfs_inspect_get_hostname (guestfs_h *g,
                               const char *root);

This function returns the hostname of the operating system as found by inspection of the guest's configuration files.

If the hostname could not be determined, then the string unknown is returned.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.7.9)

guestfs_inspect_get_icon

 char *
 guestfs_inspect_get_icon (guestfs_h *g,
                           const char *root,
                           size_t *size_r,
                           ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_INSPECT_GET_ICON_FAVICON, int favicon,
 GUESTFS_INSPECT_GET_ICON_HIGHQUALITY, int highquality,

This function returns an icon corresponding to the inspected operating system. The icon is returned as a buffer containing a PNG image (re-encoded to PNG if necessary).

If it was not possible to get an icon this function returns a zero-length (non-NULL) buffer. Callers must check for this case.

Libguestfs will start by looking for a file called /etc/favicon.png or C:\etc\favicon.png and if it has the correct format, the contents of this file will be returned. You can disable favicons by passing the optional favicon boolean as false (default is true).

If finding the favicon fails, then we look in other places in the guest for a suitable icon.

If the optional highquality boolean is true then only high quality icons are returned, which means only icons of high resolution with an alpha channel. The default (false) is to return any icon we can, even if it is of substandard quality.

Notes:

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

(Added in 1.11.12)

guestfs_inspect_get_icon_va

 char *
 guestfs_inspect_get_icon_va (guestfs_h *g,
                              const char *root,
                              size_t *size_r,
                              va_list args);

This is the "va_list variant" of "guestfs_inspect_get_icon".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_inspect_get_icon_argv

 char *
 guestfs_inspect_get_icon_argv (guestfs_h *g,
                                const char *root,
                                size_t *size_r,
                                const struct guestfs_inspect_get_icon_argv *optargs);

This is the "argv variant" of "guestfs_inspect_get_icon".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_inspect_get_major_version

 int
 guestfs_inspect_get_major_version (guestfs_h *g,
                                    const char *root);

This returns the major version number of the inspected operating system.

Windows uses a consistent versioning scheme which is not reflected in the popular public names used by the operating system. Notably the operating system known as "Windows 7" is really version 6.1 (ie. major = 6, minor = 1). You can find out the real versions corresponding to releases of Windows by consulting Wikipedia or MSDN.

If the version could not be determined, then 0 is returned.

Please read "INSPECTION" in guestfs(3) for more details.

On error this function returns -1.

(Added in 1.5.3)

guestfs_inspect_get_minor_version

 int
 guestfs_inspect_get_minor_version (guestfs_h *g,
                                    const char *root);

This returns the minor version number of the inspected operating system.

If the version could not be determined, then 0 is returned.

Please read "INSPECTION" in guestfs(3) for more details. See also guestfs_inspect_get_major_version.

On error this function returns -1.

(Added in 1.5.3)

guestfs_inspect_get_mountpoints

 char **
 guestfs_inspect_get_mountpoints (guestfs_h *g,
                                  const char *root);

This returns a hash of where we think the filesystems associated with this operating system should be mounted. Callers should note that this is at best an educated guess made by reading configuration files such as /etc/fstab. In particular note that this may return filesystems which are non-existent or not mountable and callers should be prepared to handle or ignore failures if they try to mount them.

Each element in the returned hashtable has a key which is the path of the mountpoint (eg. /boot) and a value which is the filesystem that would be mounted there (eg. /dev/sda1).

Non-mounted devices such as swap devices are not returned in this list.

For operating systems like Windows which still use drive letters, this call will only return an entry for the first drive "mounted on" /. For information about the mapping of drive letters to partitions, see guestfs_inspect_get_drive_mappings.

Please read "INSPECTION" in guestfs(3) for more details. See also guestfs_inspect_get_filesystems.

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.5.3)

guestfs_inspect_get_package_format

 char *
 guestfs_inspect_get_package_format (guestfs_h *g,
                                     const char *root);

This function and guestfs_inspect_get_package_management return the package format and package management tool used by the inspected operating system. For example for Fedora these functions would return rpm (package format) and yum (package management).

This returns the string unknown if we could not determine the package format or if the operating system does not have a real packaging system (eg. Windows).

Possible strings include: rpm, deb, ebuild, pisi, pacman, pkgsrc. Future versions of libguestfs may return other strings.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.7.5)

guestfs_inspect_get_package_management

 char *
 guestfs_inspect_get_package_management (guestfs_h *g,
                                         const char *root);

guestfs_inspect_get_package_format and this function return the package format and package management tool used by the inspected operating system. For example for Fedora these functions would return rpm (package format) and yum (package management).

This returns the string unknown if we could not determine the package management tool or if the operating system does not have a real packaging system (eg. Windows).

Possible strings include: yum, up2date, apt (for all Debian derivatives), portage, pisi, pacman, urpmi, zypper. Future versions of libguestfs may return other strings.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.7.5)

guestfs_inspect_get_product_name

 char *
 guestfs_inspect_get_product_name (guestfs_h *g,
                                   const char *root);

This returns the product name of the inspected operating system. The product name is generally some freeform string which can be displayed to the user, but should not be parsed by programs.

If the product name could not be determined, then the string unknown is returned.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_inspect_get_product_variant

 char *
 guestfs_inspect_get_product_variant (guestfs_h *g,
                                      const char *root);

This returns the product variant of the inspected operating system.

For Windows guests, this returns the contents of the Registry key HKLM\Software\Microsoft\Windows NT\CurrentVersion InstallationType which is usually a string such as Client or Server (other values are possible). This can be used to distinguish consumer and enterprise versions of Windows that have the same version number (for example, Windows 7 and Windows 2008 Server are both version 6.1, but the former is Client and the latter is Server).

For enterprise Linux guests, in future we intend this to return the product variant such as Desktop, Server and so on. But this is not implemented at present.

If the product variant could not be determined, then the string unknown is returned.

Please read "INSPECTION" in guestfs(3) for more details. See also guestfs_inspect_get_product_name, guestfs_inspect_get_major_version.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.9.13)

guestfs_inspect_get_roots

 char **
 guestfs_inspect_get_roots (guestfs_h *g);

This function is a convenient way to get the list of root devices, as returned from a previous call to guestfs_inspect_os, but without redoing the whole inspection process.

This returns an empty list if either no root devices were found or the caller has not called guestfs_inspect_os.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.7.3)

guestfs_inspect_get_type

 char *
 guestfs_inspect_get_type (guestfs_h *g,
                           const char *root);

This returns the type of the inspected operating system. Currently defined types are:

"linux"

Any Linux-based operating system.

"windows"

Any Microsoft Windows operating system.

"freebsd"

FreeBSD.

"netbsd"

NetBSD.

"openbsd"

OpenBSD.

"hurd"

GNU/Hurd.

"dos"

MS-DOS, FreeDOS and others.

"unknown"

The operating system type could not be determined.

Future versions of libguestfs may return other strings here. The caller should be prepared to handle any string.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.3)

guestfs_inspect_get_windows_current_control_set

 char *
 guestfs_inspect_get_windows_current_control_set (guestfs_h *g,
                                                  const char *root);

This returns the Windows CurrentControlSet of the inspected guest. The CurrentControlSet is a registry key name such as ControlSet001.

This call assumes that the guest is Windows and that the Registry could be examined by inspection. If this is not the case then an error is returned.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.9.17)

guestfs_inspect_get_windows_systemroot

 char *
 guestfs_inspect_get_windows_systemroot (guestfs_h *g,
                                         const char *root);

This returns the Windows systemroot of the inspected guest. The systemroot is a directory path such as /WINDOWS.

This call assumes that the guest is Windows and that the systemroot could be determined by inspection. If this is not the case then an error is returned.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.25)

guestfs_inspect_is_live

 int
 guestfs_inspect_is_live (guestfs_h *g,
                          const char *root);

If guestfs_inspect_get_format returns installer (this is an install disk), then this returns true if a live image was detected on the disk.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a C truth value on success or -1 on error.

(Added in 1.9.4)

guestfs_inspect_is_multipart

 int
 guestfs_inspect_is_multipart (guestfs_h *g,
                               const char *root);

If guestfs_inspect_get_format returns installer (this is an install disk), then this returns true if the disk is part of a set.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a C truth value on success or -1 on error.

(Added in 1.9.4)

guestfs_inspect_is_netinst

 int
 guestfs_inspect_is_netinst (guestfs_h *g,
                             const char *root);

If guestfs_inspect_get_format returns installer (this is an install disk), then this returns true if the disk is a network installer, ie. not a self-contained install CD but one which is likely to require network access to complete the install.

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a C truth value on success or -1 on error.

(Added in 1.9.4)

guestfs_inspect_list_applications

 struct guestfs_application_list *
 guestfs_inspect_list_applications (guestfs_h *g,
                                    const char *root);

This function is deprecated. In new code, use the "guestfs_inspect_list_applications2" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Return the list of applications installed in the operating system.

Note: This call works differently from other parts of the inspection API. You have to call guestfs_inspect_os, then guestfs_inspect_get_mountpoints, then mount up the disks, before calling this. Listing applications is a significantly more difficult operation which requires access to the full filesystem. Also note that unlike the other guestfs_inspect_get_* calls which are just returning data cached in the libguestfs handle, this call actually reads parts of the mounted filesystems during the call.

This returns an empty list if the inspection code was not able to determine the list of applications.

The application structure contains the following fields:

app_name

The name of the application. For Red Hat-derived and Debian-derived Linux guests, this is the package name.

app_display_name

The display name of the application, sometimes localized to the install language of the guest operating system.

If unavailable this is returned as an empty string "". Callers needing to display something can use app_name instead.

app_epoch

For package managers which use epochs, this contains the epoch of the package (an integer). If unavailable, this is returned as 0.

app_version

The version string of the application or package. If unavailable this is returned as an empty string "".

app_release

The release string of the application or package, for package managers that use this. If unavailable this is returned as an empty string "".

app_install_path

The installation path of the application (on operating systems such as Windows which use installation paths). This path is in the format used by the guest operating system, it is not a libguestfs path.

If unavailable this is returned as an empty string "".

app_trans_path

The install path translated into a libguestfs path. If unavailable this is returned as an empty string "".

app_publisher

The name of the publisher of the application, for package managers that use this. If unavailable this is returned as an empty string "".

app_url

The URL (eg. upstream URL) of the application. If unavailable this is returned as an empty string "".

app_source_package

For packaging systems which support this, the name of the source package. If unavailable this is returned as an empty string "".

app_summary

A short (usually one line) description of the application or package. If unavailable this is returned as an empty string "".

app_description

A longer description of the application or package. If unavailable this is returned as an empty string "".

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a struct guestfs_application_list *, or NULL if there was an error. The caller must call guestfs_free_application_list after use.

(Added in 1.7.8)

guestfs_inspect_list_applications2

 struct guestfs_application2_list *
 guestfs_inspect_list_applications2 (guestfs_h *g,
                                     const char *root);

Return the list of applications installed in the operating system.

Note: This call works differently from other parts of the inspection API. You have to call guestfs_inspect_os, then guestfs_inspect_get_mountpoints, then mount up the disks, before calling this. Listing applications is a significantly more difficult operation which requires access to the full filesystem. Also note that unlike the other guestfs_inspect_get_* calls which are just returning data cached in the libguestfs handle, this call actually reads parts of the mounted filesystems during the call.

This returns an empty list if the inspection code was not able to determine the list of applications.

The application structure contains the following fields:

app2_name

The name of the application. For Red Hat-derived and Debian-derived Linux guests, this is the package name.

app2_display_name

The display name of the application, sometimes localized to the install language of the guest operating system.

If unavailable this is returned as an empty string "". Callers needing to display something can use app2_name instead.

app2_epoch

For package managers which use epochs, this contains the epoch of the package (an integer). If unavailable, this is returned as 0.

app2_version

The version string of the application or package. If unavailable this is returned as an empty string "".

app2_release

The release string of the application or package, for package managers that use this. If unavailable this is returned as an empty string "".

app2_arch

The architecture string of the application or package, for package managers that use this. If unavailable this is returned as an empty string "".

app2_install_path

The installation path of the application (on operating systems such as Windows which use installation paths). This path is in the format used by the guest operating system, it is not a libguestfs path.

If unavailable this is returned as an empty string "".

app2_trans_path

The install path translated into a libguestfs path. If unavailable this is returned as an empty string "".

app2_publisher

The name of the publisher of the application, for package managers that use this. If unavailable this is returned as an empty string "".

app2_url

The URL (eg. upstream URL) of the application. If unavailable this is returned as an empty string "".

app2_source_package

For packaging systems which support this, the name of the source package. If unavailable this is returned as an empty string "".

app2_summary

A short (usually one line) description of the application or package. If unavailable this is returned as an empty string "".

app2_description

A longer description of the application or package. If unavailable this is returned as an empty string "".

Please read "INSPECTION" in guestfs(3) for more details.

This function returns a struct guestfs_application2_list *, or NULL if there was an error. The caller must call guestfs_free_application2_list after use.

(Added in 1.19.56)

guestfs_inspect_os

 char **
 guestfs_inspect_os (guestfs_h *g);

This function uses other libguestfs functions and certain heuristics to inspect the disk(s) (usually disks belonging to a virtual machine), looking for operating systems.

The list returned is empty if no operating systems were found.

If one operating system was found, then this returns a list with a single element, which is the name of the root filesystem of this operating system. It is also possible for this function to return a list containing more than one element, indicating a dual-boot or multi-boot virtual machine, with each element being the root filesystem of one of the operating systems.

You can pass the root string(s) returned to other guestfs_inspect_get_* functions in order to query further information about each operating system, such as the name and version.

This function uses other libguestfs features such as guestfs_mount_ro and guestfs_umount_all in order to mount and unmount filesystems and look at the contents. This should be called with no disks currently mounted. The function may also use Augeas, so any existing Augeas handle will be closed.

This function cannot decrypt encrypted disks. The caller must do that first (supplying the necessary keys) if the disk is encrypted.

Please read "INSPECTION" in guestfs(3) for more details.

See also guestfs_list_filesystems.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.5.3)

guestfs_is_blockdev

 int
 guestfs_is_blockdev (guestfs_h *g,
                      const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_is_blockdev_opts" with no optional arguments.

(Added in 1.5.10)

guestfs_is_blockdev_opts

 int
 guestfs_is_blockdev_opts (guestfs_h *g,
                           const char *path,
                           ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_IS_BLOCKDEV_OPTS_FOLLOWSYMLINKS, int followsymlinks,

This returns true if and only if there is a block device with the given path name.

If the optional flag followsymlinks is true, then a symlink (or chain of symlinks) that ends with a block device also causes the function to return true.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.4)

guestfs_is_blockdev_opts_va

 int
 guestfs_is_blockdev_opts_va (guestfs_h *g,
                              const char *path,
                              va_list args);

This is the "va_list variant" of "guestfs_is_blockdev_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_blockdev_opts_argv

 int
 guestfs_is_blockdev_opts_argv (guestfs_h *g,
                                const char *path,
                                const struct guestfs_is_blockdev_opts_argv *optargs);

This is the "argv variant" of "guestfs_is_blockdev_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_busy

 int
 guestfs_is_busy (guestfs_h *g);

This always returns false. This function is deprecated with no replacement. Do not use this function.

For more information on states, see guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.0.2)

guestfs_is_chardev

 int
 guestfs_is_chardev (guestfs_h *g,
                     const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_is_chardev_opts" with no optional arguments.

(Added in 1.5.10)

guestfs_is_chardev_opts

 int
 guestfs_is_chardev_opts (guestfs_h *g,
                          const char *path,
                          ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_IS_CHARDEV_OPTS_FOLLOWSYMLINKS, int followsymlinks,

This returns true if and only if there is a character device with the given path name.

If the optional flag followsymlinks is true, then a symlink (or chain of symlinks) that ends with a chardev also causes the function to return true.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.4)

guestfs_is_chardev_opts_va

 int
 guestfs_is_chardev_opts_va (guestfs_h *g,
                             const char *path,
                             va_list args);

This is the "va_list variant" of "guestfs_is_chardev_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_chardev_opts_argv

 int
 guestfs_is_chardev_opts_argv (guestfs_h *g,
                               const char *path,
                               const struct guestfs_is_chardev_opts_argv *optargs);

This is the "argv variant" of "guestfs_is_chardev_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_config

 int
 guestfs_is_config (guestfs_h *g);

This returns true iff this handle is being configured (in the CONFIG state).

For more information on states, see guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.0.2)

guestfs_is_dir

 int
 guestfs_is_dir (guestfs_h *g,
                 const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_is_dir_opts" with no optional arguments.

(Added in 0.8)

guestfs_is_dir_opts

 int
 guestfs_is_dir_opts (guestfs_h *g,
                      const char *path,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_IS_DIR_OPTS_FOLLOWSYMLINKS, int followsymlinks,

This returns true if and only if there is a directory with the given path name. Note that it returns false for other objects like files.

If the optional flag followsymlinks is true, then a symlink (or chain of symlinks) that ends with a directory also causes the function to return true.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.4)

guestfs_is_dir_opts_va

 int
 guestfs_is_dir_opts_va (guestfs_h *g,
                         const char *path,
                         va_list args);

This is the "va_list variant" of "guestfs_is_dir_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_dir_opts_argv

 int
 guestfs_is_dir_opts_argv (guestfs_h *g,
                           const char *path,
                           const struct guestfs_is_dir_opts_argv *optargs);

This is the "argv variant" of "guestfs_is_dir_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_fifo

 int
 guestfs_is_fifo (guestfs_h *g,
                  const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_is_fifo_opts" with no optional arguments.

(Added in 1.5.10)

guestfs_is_fifo_opts

 int
 guestfs_is_fifo_opts (guestfs_h *g,
                       const char *path,
                       ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_IS_FIFO_OPTS_FOLLOWSYMLINKS, int followsymlinks,

This returns true if and only if there is a FIFO (named pipe) with the given path name.

If the optional flag followsymlinks is true, then a symlink (or chain of symlinks) that ends with a FIFO also causes the function to return true.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.4)

guestfs_is_fifo_opts_va

 int
 guestfs_is_fifo_opts_va (guestfs_h *g,
                          const char *path,
                          va_list args);

This is the "va_list variant" of "guestfs_is_fifo_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_fifo_opts_argv

 int
 guestfs_is_fifo_opts_argv (guestfs_h *g,
                            const char *path,
                            const struct guestfs_is_fifo_opts_argv *optargs);

This is the "argv variant" of "guestfs_is_fifo_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_file

 int
 guestfs_is_file (guestfs_h *g,
                  const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_is_file_opts" with no optional arguments.

(Added in 0.8)

guestfs_is_file_opts

 int
 guestfs_is_file_opts (guestfs_h *g,
                       const char *path,
                       ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_IS_FILE_OPTS_FOLLOWSYMLINKS, int followsymlinks,

This returns true if and only if there is a regular file with the given path name. Note that it returns false for other objects like directories.

If the optional flag followsymlinks is true, then a symlink (or chain of symlinks) that ends with a file also causes the function to return true.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.4)

guestfs_is_file_opts_va

 int
 guestfs_is_file_opts_va (guestfs_h *g,
                          const char *path,
                          va_list args);

This is the "va_list variant" of "guestfs_is_file_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_file_opts_argv

 int
 guestfs_is_file_opts_argv (guestfs_h *g,
                            const char *path,
                            const struct guestfs_is_file_opts_argv *optargs);

This is the "argv variant" of "guestfs_is_file_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_launching

 int
 guestfs_is_launching (guestfs_h *g);

This returns true iff this handle is launching the subprocess (in the LAUNCHING state).

For more information on states, see guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.0.2)

guestfs_is_lv

 int
 guestfs_is_lv (guestfs_h *g,
                const char *device);

This command tests whether device is a logical volume, and returns true iff this is the case.

This function returns a C truth value on success or -1 on error.

(Added in 1.5.3)

guestfs_is_ready

 int
 guestfs_is_ready (guestfs_h *g);

This returns true iff this handle is ready to accept commands (in the READY state).

For more information on states, see guestfs(3).

This function returns a C truth value on success or -1 on error.

(Added in 1.0.2)

guestfs_is_socket

 int
 guestfs_is_socket (guestfs_h *g,
                    const char *path);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_is_socket_opts" with no optional arguments.

(Added in 1.5.10)

guestfs_is_socket_opts

 int
 guestfs_is_socket_opts (guestfs_h *g,
                         const char *path,
                         ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_IS_SOCKET_OPTS_FOLLOWSYMLINKS, int followsymlinks,

This returns true if and only if there is a Unix domain socket with the given path name.

If the optional flag followsymlinks is true, then a symlink (or chain of symlinks) that ends with a socket also causes the function to return true.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.4)

guestfs_is_socket_opts_va

 int
 guestfs_is_socket_opts_va (guestfs_h *g,
                            const char *path,
                            va_list args);

This is the "va_list variant" of "guestfs_is_socket_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_is_socket_opts_argv

 int
 guestfs_is_socket_opts_argv (guestfs_h *g,
                              const char *path,
                              const struct guestfs_is_socket_opts_argv *optargs);

This is the "argv variant" of "guestfs_is_socket_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

 int
 guestfs_is_symlink (guestfs_h *g,
                     const char *path);

This returns true if and only if there is a symbolic link with the given path name.

See also guestfs_stat.

This function returns a C truth value on success or -1 on error.

(Added in 1.5.10)

guestfs_is_whole_device

 int
 guestfs_is_whole_device (guestfs_h *g,
                          const char *device);

This returns true if and only if device refers to a whole block device. That is, not a partition or a logical device.

This function returns a C truth value on success or -1 on error.

(Added in 1.21.9)

guestfs_is_zero

 int
 guestfs_is_zero (guestfs_h *g,
                  const char *path);

This returns true iff the file exists and the file is empty or it contains all zero bytes.

This function returns a C truth value on success or -1 on error.

(Added in 1.11.8)

guestfs_is_zero_device

 int
 guestfs_is_zero_device (guestfs_h *g,
                         const char *device);

This returns true iff the device exists and contains all zero bytes.

Note that for large devices this can take a long time to run.

This function returns a C truth value on success or -1 on error.

(Added in 1.11.8)

guestfs_isoinfo

 struct guestfs_isoinfo *
 guestfs_isoinfo (guestfs_h *g,
                  const char *isofile);

This is the same as guestfs_isoinfo_device except that it works for an ISO file located inside some other mounted filesystem. Note that in the common case where you have added an ISO file as a libguestfs device, you would not call this. Instead you would call guestfs_isoinfo_device.

This function returns a struct guestfs_isoinfo *, or NULL if there was an error. The caller must call guestfs_free_isoinfo after use.

(Added in 1.17.19)

guestfs_isoinfo_device

 struct guestfs_isoinfo *
 guestfs_isoinfo_device (guestfs_h *g,
                         const char *device);

device is an ISO device. This returns a struct of information read from the primary volume descriptor (the ISO equivalent of the superblock) of the device.

Usually it is more efficient to use the isoinfo(1) command with the -d option on the host to analyze ISO files, instead of going through libguestfs.

For information on the primary volume descriptor fields, see http://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor

This function returns a struct guestfs_isoinfo *, or NULL if there was an error. The caller must call guestfs_free_isoinfo after use.

(Added in 1.17.19)

guestfs_journal_close

 int
 guestfs_journal_close (guestfs_h *g);

Close the journal handle.

This function returns 0 on success or -1 on error.

(Added in 1.23.11)

guestfs_journal_get

 struct guestfs_xattr_list *
 guestfs_journal_get (guestfs_h *g);

Read the current journal entry. This returns all the fields in the journal as a set of (attrname, attrval) pairs. The attrname is the field name (a string).

The attrval is the field value (a binary blob, often but not always a string). Please note that attrval is a byte array, not a \0-terminated C string.

The length of data may be truncated to the data threshold (see: guestfs_journal_set_data_threshold, guestfs_journal_get_data_threshold).

If you set the data threshold to unlimited (0) then this call can read a journal entry of any size, ie. it is not limited by the libguestfs protocol.

This function returns a struct guestfs_xattr_list *, or NULL if there was an error. The caller must call guestfs_free_xattr_list after use.

(Added in 1.23.11)

guestfs_journal_get_data_threshold

 int64_t
 guestfs_journal_get_data_threshold (guestfs_h *g);

Get the current data threshold for reading journal entries. This is a hint to the journal that it may truncate data fields to this size when reading them (note also that it may not truncate them). If this returns 0, then the threshold is unlimited.

See also guestfs_journal_set_data_threshold.

On error this function returns -1.

(Added in 1.23.11)

guestfs_journal_next

 int
 guestfs_journal_next (guestfs_h *g);

Move to the next journal entry. You have to call this at least once after opening the handle before you are able to read data.

The returned boolean tells you if there are any more journal records to read. true means you can read the next record (eg. using guestfs_journal_get_data), and false means you have reached the end of the journal.

This function returns a C truth value on success or -1 on error.

(Added in 1.23.11)

guestfs_journal_open

 int
 guestfs_journal_open (guestfs_h *g,
                       const char *directory);

Open the systemd journal located in directory. Any previously opened journal handle is closed.

The contents of the journal can be read using guestfs_journal_next and guestfs_journal_get.

After you have finished using the journal, you should close the handle by calling guestfs_journal_close.

This function returns 0 on success or -1 on error.

(Added in 1.23.11)

guestfs_journal_set_data_threshold

 int
 guestfs_journal_set_data_threshold (guestfs_h *g,
                                     int64_t threshold);

Set the data threshold for reading journal entries. This is a hint to the journal that it may truncate data fields to this size when reading them (note also that it may not truncate them). If you set this to 0, then the threshold is unlimited.

See also guestfs_journal_get_data_threshold.

This function returns 0 on success or -1 on error.

(Added in 1.23.11)

guestfs_journal_skip

 int64_t
 guestfs_journal_skip (guestfs_h *g,
                       int64_t skip);

Skip forwards (skip ≥ 0) or backwards (skip < 0) in the journal.

The number of entries actually skipped is returned (note rskip ≥ 0). If this is not the same as the absolute value of the skip parameter (|skip|) you passed in then it means you have reached the end or the start of the journal.

On error this function returns -1.

(Added in 1.23.11)

guestfs_kill_subprocess

 int
 guestfs_kill_subprocess (guestfs_h *g);

This function is deprecated. In new code, use the "guestfs_shutdown" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This kills the hypervisor.

Do not call this. See: guestfs_shutdown instead.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_launch

 int
 guestfs_launch (guestfs_h *g);

You should call this after configuring the handle (eg. adding drives) but before performing any actions.

Do not call guestfs_launch twice on the same handle. Although it will not give an error (for historical reasons), the precise behaviour when you do this is not well defined. Handles are very cheap to create, so create a new one for each launch.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 0.3)

guestfs_lchown

 int
 guestfs_lchown (guestfs_h *g,
                 int owner,
                 int group,
                 const char *path);

Change the file owner to owner and group to group. This is like guestfs_chown but if path is a symlink then the link itself is changed, not the target.

Only numeric uid and gid are supported. If you want to use names, you will need to locate and parse the password file yourself (Augeas support makes this relatively easy).

This function returns 0 on success or -1 on error.

(Added in 1.0.77)

guestfs_ldmtool_create_all

 int
 guestfs_ldmtool_create_all (guestfs_h *g);

This function scans all block devices looking for Windows dynamic disk volumes and partitions, and creates devices for any that were found.

Call guestfs_list_ldm_volumes and guestfs_list_ldm_partitions to return all devices.

Note that you don't normally need to call this explicitly, since it is done automatically at guestfs_launch time. However you might want to call this function if you have hotplugged disks or have just created a Windows dynamic disk.

This function returns 0 on success or -1 on error.

(Added in 1.20.0)

guestfs_ldmtool_diskgroup_disks

 char **
 guestfs_ldmtool_diskgroup_disks (guestfs_h *g,
                                  const char *diskgroup);

Return the disks in a Windows dynamic disk group. The diskgroup parameter should be the GUID of a disk group, one element from the list returned by guestfs_ldmtool_scan.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_ldmtool_diskgroup_name

 char *
 guestfs_ldmtool_diskgroup_name (guestfs_h *g,
                                 const char *diskgroup);

Return the name of a Windows dynamic disk group. The diskgroup parameter should be the GUID of a disk group, one element from the list returned by guestfs_ldmtool_scan.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.20.0)

guestfs_ldmtool_diskgroup_volumes

 char **
 guestfs_ldmtool_diskgroup_volumes (guestfs_h *g,
                                    const char *diskgroup);

Return the volumes in a Windows dynamic disk group. The diskgroup parameter should be the GUID of a disk group, one element from the list returned by guestfs_ldmtool_scan.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_ldmtool_remove_all

 int
 guestfs_ldmtool_remove_all (guestfs_h *g);

This is essentially the opposite of guestfs_ldmtool_create_all. It removes the device mapper mappings for all Windows dynamic disk volumes

This function returns 0 on success or -1 on error.

(Added in 1.20.0)

guestfs_ldmtool_scan

 char **
 guestfs_ldmtool_scan (guestfs_h *g);

This function scans for Windows dynamic disks. It returns a list of identifiers (GUIDs) for all disk groups that were found. These identifiers can be passed to other guestfs_ldmtool_* functions.

This function scans all block devices. To scan a subset of block devices, call guestfs_ldmtool_scan_devices instead.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_ldmtool_scan_devices

 char **
 guestfs_ldmtool_scan_devices (guestfs_h *g,
                               char *const *devices);

This function scans for Windows dynamic disks. It returns a list of identifiers (GUIDs) for all disk groups that were found. These identifiers can be passed to other guestfs_ldmtool_* functions.

The parameter devices is a list of block devices which are scanned. If this list is empty, all block devices are scanned.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_ldmtool_volume_hint

 char *
 guestfs_ldmtool_volume_hint (guestfs_h *g,
                              const char *diskgroup,
                              const char *volume);

Return the hint field of the volume named volume in the disk group with GUID diskgroup. This may not be defined, in which case the empty string is returned. The hint field is often, though not always, the name of a Windows drive, eg. E:.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.20.0)

guestfs_ldmtool_volume_partitions

 char **
 guestfs_ldmtool_volume_partitions (guestfs_h *g,
                                    const char *diskgroup,
                                    const char *volume);

Return the list of partitions in the volume named volume in the disk group with GUID diskgroup.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_ldmtool_volume_type

 char *
 guestfs_ldmtool_volume_type (guestfs_h *g,
                              const char *diskgroup,
                              const char *volume);

Return the type of the volume named volume in the disk group with GUID diskgroup.

Possible volume types that can be returned here include: simple, spanned, striped, mirrored, raid5. Other types may also be returned.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.20.0)

guestfs_lgetxattr

 char *
 guestfs_lgetxattr (guestfs_h *g,
                    const char *path,
                    const char *name,
                    size_t *size_r);

Get a single extended attribute from file path named name. If path is a symlink, then this call returns an extended attribute from the symlink.

Normally it is better to get all extended attributes from a file in one go by calling guestfs_getxattrs. However some Linux filesystem implementations are buggy and do not provide a way to list out attributes. For these filesystems (notably ntfs-3g) you have to know the names of the extended attributes you want in advance and call this function.

Extended attribute values are blobs of binary data. If there is no extended attribute named name, this returns an error.

See also: guestfs_lgetxattrs, guestfs_getxattr, attr(5).

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

(Added in 1.7.24)

guestfs_lgetxattrs

 struct guestfs_xattr_list *
 guestfs_lgetxattrs (guestfs_h *g,
                     const char *path);

This is the same as guestfs_getxattrs, but if path is a symbolic link, then it returns the extended attributes of the link itself.

This function returns a struct guestfs_xattr_list *, or NULL if there was an error. The caller must call guestfs_free_xattr_list after use.

(Added in 1.0.59)

guestfs_list_9p

 char **
 guestfs_list_9p (guestfs_h *g);

List all 9p filesystems attached to the guest. A list of mount tags is returned.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.11.12)

guestfs_list_devices

 char **
 guestfs_list_devices (guestfs_h *g);

List all the block devices.

The full block device names are returned, eg. /dev/sda.

See also guestfs_list_filesystems.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.4)

guestfs_list_disk_labels

 char **
 guestfs_list_disk_labels (guestfs_h *g);

If you add drives using the optional label parameter of guestfs_add_drive_opts, you can use this call to map between disk labels, and raw block device and partition names (like /dev/sda and /dev/sda1).

This returns a hashtable, where keys are the disk labels (without the /dev/disk/guestfs prefix), and the values are the full raw block device and partition names (eg. /dev/sda and /dev/sda1).

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.19.49)

guestfs_list_dm_devices

 char **
 guestfs_list_dm_devices (guestfs_h *g);

List all device mapper devices.

The returned list contains /dev/mapper/* devices, eg. ones created by a previous call to guestfs_luks_open.

Device mapper devices which correspond to logical volumes are not returned in this list. Call guestfs_lvs if you want to list logical volumes.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.11.15)

guestfs_list_filesystems

 char **
 guestfs_list_filesystems (guestfs_h *g);

This inspection command looks for filesystems on partitions, block devices and logical volumes, returning a list of mountables containing filesystems and their type.

The return value is a hash, where the keys are the devices containing filesystems, and the values are the filesystem types. For example:

 "/dev/sda1" => "ntfs"
 "/dev/sda2" => "ext2"
 "/dev/vg_guest/lv_root" => "ext4"
 "/dev/vg_guest/lv_swap" => "swap"

The key is not necessarily a block device. It may also be an opaque 'mountable' string which can be passed to guestfs_mount.

The value can have the special value "unknown", meaning the content of the device is undetermined or empty. "swap" means a Linux swap partition.

This command runs other libguestfs commands, which might include guestfs_mount and guestfs_umount, and therefore you should use this soon after launch and only when nothing is mounted.

Not all of the filesystems returned will be mountable. In particular, swap partitions are returned in the list. Also this command does not check that each filesystem found is valid and mountable, and some filesystems might be mountable but require special options. Filesystems may not all belong to a single logical operating system (use guestfs_inspect_os to look for OSes).

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.5.15)

guestfs_list_ldm_partitions

 char **
 guestfs_list_ldm_partitions (guestfs_h *g);

This function returns all Windows dynamic disk partitions that were found at launch time. It returns a list of device names.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_list_ldm_volumes

 char **
 guestfs_list_ldm_volumes (guestfs_h *g);

This function returns all Windows dynamic disk volumes that were found at launch time. It returns a list of device names.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.20.0)

guestfs_list_md_devices

 char **
 guestfs_list_md_devices (guestfs_h *g);

List all Linux md devices.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.15.4)

guestfs_list_partitions

 char **
 guestfs_list_partitions (guestfs_h *g);

List all the partitions detected on all block devices.

The full partition device names are returned, eg. /dev/sda1

This does not return logical volumes. For that you will need to call guestfs_lvs.

See also guestfs_list_filesystems.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.4)

guestfs_ll

 char *
 guestfs_ll (guestfs_h *g,
             const char *directory);

List the files in directory (relative to the root directory, there is no cwd) in the format of 'ls -la'.

This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 0.4)

guestfs_llz

 char *
 guestfs_llz (guestfs_h *g,
              const char *directory);

List the files in directory in the format of 'ls -laZ'.

This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.17.6)

guestfs_ln

 int
 guestfs_ln (guestfs_h *g,
             const char *target,
             const char *linkname);

This command creates a hard link using the ln command.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_ln_f

 int
 guestfs_ln_f (guestfs_h *g,
               const char *target,
               const char *linkname);

This command creates a hard link using the ln -f command. The -f option removes the link (linkname) if it exists already.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_ln_s

 int
 guestfs_ln_s (guestfs_h *g,
               const char *target,
               const char *linkname);

This command creates a symbolic link using the ln -s command.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_ln_sf

 int
 guestfs_ln_sf (guestfs_h *g,
                const char *target,
                const char *linkname);

This command creates a symbolic link using the ln -sf command, The -f option removes the link (linkname) if it exists already.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_lremovexattr

 int
 guestfs_lremovexattr (guestfs_h *g,
                       const char *xattr,
                       const char *path);

This is the same as guestfs_removexattr, but if path is a symbolic link, then it removes an extended attribute of the link itself.

This function returns 0 on success or -1 on error.

(Added in 1.0.59)

guestfs_ls

 char **
 guestfs_ls (guestfs_h *g,
             const char *directory);

List the files in directory (relative to the root directory, there is no cwd). The '.' and '..' entries are not returned, but hidden files are shown.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.4)

guestfs_ls0

 int
 guestfs_ls0 (guestfs_h *g,
              const char *dir,
              const char *filenames);

This specialized command is used to get a listing of the filenames in the directory dir. The list of filenames is written to the local file filenames (on the host).

In the output file, the filenames are separated by \0 characters.

. and .. are not returned. The filenames are not sorted.

This function returns 0 on success or -1 on error.

(Added in 1.19.32)

guestfs_lsetxattr

 int
 guestfs_lsetxattr (guestfs_h *g,
                    const char *xattr,
                    const char *val,
                    int vallen,
                    const char *path);

This is the same as guestfs_setxattr, but if path is a symbolic link, then it sets an extended attribute of the link itself.

This function returns 0 on success or -1 on error.

(Added in 1.0.59)

guestfs_lstat

 struct guestfs_stat *
 guestfs_lstat (guestfs_h *g,
                const char *path);

Returns file information for the given path.

This is the same as guestfs_stat except that if path is a symbolic link, then the link is stat-ed, not the file it refers to.

This is the same as the lstat(2) system call.

This function returns a struct guestfs_stat *, or NULL if there was an error. The caller must call guestfs_free_stat after use.

(Added in 0.9.2)

guestfs_lstatlist

 struct guestfs_stat_list *
 guestfs_lstatlist (guestfs_h *g,
                    const char *path,
                    char *const *names);

This call allows you to perform the guestfs_lstat operation on multiple files, where all files are in the directory path. names is the list of files from this directory.

On return you get a list of stat structs, with a one-to-one correspondence to the names list. If any name did not exist or could not be lstat'd, then the ino field of that structure is set to -1.

This call is intended for programs that want to efficiently list a directory contents without making many round-trips. See also guestfs_lxattrlist for a similarly efficient call for getting extended attributes.

This function returns a struct guestfs_stat_list *, or NULL if there was an error. The caller must call guestfs_free_stat_list after use.

(Added in 1.0.77)

guestfs_luks_add_key

 int
 guestfs_luks_add_key (guestfs_h *g,
                       const char *device,
                       const char *key,
                       const char *newkey,
                       int keyslot);

This command adds a new key on LUKS device device. key is any existing key, and is used to access the device. newkey is the new key to add. keyslot is the key slot that will be replaced.

Note that if keyslot already contains a key, then this command will fail. You have to use guestfs_luks_kill_slot first to remove that key.

This function returns 0 on success or -1 on error.

This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information.

(Added in 1.5.2)

guestfs_luks_close

 int
 guestfs_luks_close (guestfs_h *g,
                     const char *device);

This closes a LUKS device that was created earlier by guestfs_luks_open or guestfs_luks_open_ro. The device parameter must be the name of the LUKS mapping device (ie. /dev/mapper/mapname) and not the name of the underlying block device.

This function returns 0 on success or -1 on error.

(Added in 1.5.1)

guestfs_luks_format

 int
 guestfs_luks_format (guestfs_h *g,
                      const char *device,
                      const char *key,
                      int keyslot);

This command erases existing data on device and formats the device as a LUKS encrypted device. key is the initial key, which is added to key slot slot. (LUKS supports 8 key slots, numbered 0-7).

This function returns 0 on success or -1 on error.

This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information.

(Added in 1.5.2)

guestfs_luks_format_cipher

 int
 guestfs_luks_format_cipher (guestfs_h *g,
                             const char *device,
                             const char *key,
                             int keyslot,
                             const char *cipher);

This command is the same as guestfs_luks_format but it also allows you to set the cipher used.

This function returns 0 on success or -1 on error.

This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information.

(Added in 1.5.2)

guestfs_luks_kill_slot

 int
 guestfs_luks_kill_slot (guestfs_h *g,
                         const char *device,
                         const char *key,
                         int keyslot);

This command deletes the key in key slot keyslot from the encrypted LUKS device device. key must be one of the other keys.

This function returns 0 on success or -1 on error.

This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information.

(Added in 1.5.2)

guestfs_luks_open

 int
 guestfs_luks_open (guestfs_h *g,
                    const char *device,
                    const char *key,
                    const char *mapname);

This command opens a block device which has been encrypted according to the Linux Unified Key Setup (LUKS) standard.

device is the encrypted block device or partition.

The caller must supply one of the keys associated with the LUKS block device, in the key parameter.

This creates a new block device called /dev/mapper/mapname. Reads and writes to this block device are decrypted from and encrypted to the underlying device respectively.

If this block device contains LVM volume groups, then calling guestfs_vgscan followed by guestfs_vg_activate_all will make them visible.

Use guestfs_list_dm_devices to list all device mapper devices.

This function returns 0 on success or -1 on error.

This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information.

(Added in 1.5.1)

guestfs_luks_open_ro

 int
 guestfs_luks_open_ro (guestfs_h *g,
                       const char *device,
                       const char *key,
                       const char *mapname);

This is the same as guestfs_luks_open except that a read-only mapping is created.

This function returns 0 on success or -1 on error.

This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information.

(Added in 1.5.1)

guestfs_lvcreate

 int
 guestfs_lvcreate (guestfs_h *g,
                   const char *logvol,
                   const char *volgroup,
                   int mbytes);

This creates an LVM logical volume called logvol on the volume group volgroup, with size megabytes.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_lvcreate_free

 int
 guestfs_lvcreate_free (guestfs_h *g,
                        const char *logvol,
                        const char *volgroup,
                        int percent);

Create an LVM logical volume called /dev/volgroup/logvol, using approximately percent % of the free space remaining in the volume group. Most usefully, when percent is 100 this will create the largest possible LV.

This function returns 0 on success or -1 on error.

(Added in 1.17.18)

guestfs_lvm_canonical_lv_name

 char *
 guestfs_lvm_canonical_lv_name (guestfs_h *g,
                                const char *lvname);

This converts alternative naming schemes for LVs that you might find to the canonical name. For example, /dev/mapper/VG-LV is converted to /dev/VG/LV.

This command returns an error if the lvname parameter does not refer to a logical volume.

See also guestfs_is_lv, guestfs_canonical_device_name.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.24)

guestfs_lvm_clear_filter

 int
 guestfs_lvm_clear_filter (guestfs_h *g);

This undoes the effect of guestfs_lvm_set_filter. LVM will be able to see every block device.

This command also clears the LVM cache and performs a volume group scan.

This function returns 0 on success or -1 on error.

(Added in 1.5.1)

guestfs_lvm_remove_all

 int
 guestfs_lvm_remove_all (guestfs_h *g);

This command removes all LVM logical volumes, volume groups and physical volumes.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_lvm_set_filter

 int
 guestfs_lvm_set_filter (guestfs_h *g,
                         char *const *devices);

This sets the LVM device filter so that LVM will only be able to "see" the block devices in the list devices, and will ignore all other attached block devices.

Where disk image(s) contain duplicate PVs or VGs, this command is useful to get LVM to ignore the duplicates, otherwise LVM can get confused. Note also there are two types of duplication possible: either cloned PVs/VGs which have identical UUIDs; or VGs that are not cloned but just happen to have the same name. In normal operation you cannot create this situation, but you can do it outside LVM, eg. by cloning disk images or by bit twiddling inside the LVM metadata.

This command also clears the LVM cache and performs a volume group scan.

You can filter whole block devices or individual partitions.

You cannot use this if any VG is currently in use (eg. contains a mounted filesystem), even if you are not filtering out that VG.

This function returns 0 on success or -1 on error.

(Added in 1.5.1)

guestfs_lvremove

 int
 guestfs_lvremove (guestfs_h *g,
                   const char *device);

Remove an LVM logical volume device, where device is the path to the LV, such as /dev/VG/LV.

You can also remove all LVs in a volume group by specifying the VG name, /dev/VG.

This function returns 0 on success or -1 on error.

(Added in 1.0.13)

guestfs_lvrename

 int
 guestfs_lvrename (guestfs_h *g,
                   const char *logvol,
                   const char *newlogvol);

Rename a logical volume logvol with the new name newlogvol.

This function returns 0 on success or -1 on error.

(Added in 1.0.83)

guestfs_lvresize

 int
 guestfs_lvresize (guestfs_h *g,
                   const char *device,
                   int mbytes);

This resizes (expands or shrinks) an existing LVM logical volume to mbytes. When reducing, data in the reduced part is lost.

This function returns 0 on success or -1 on error.

(Added in 1.0.27)

guestfs_lvresize_free

 int
 guestfs_lvresize_free (guestfs_h *g,
                        const char *lv,
                        int percent);

This expands an existing logical volume lv so that it fills pc% of the remaining free space in the volume group. Commonly you would call this with pc = 100 which expands the logical volume as much as possible, using all remaining free space in the volume group.

This function returns 0 on success or -1 on error.

(Added in 1.3.3)

guestfs_lvs

 char **
 guestfs_lvs (guestfs_h *g);

List all the logical volumes detected. This is the equivalent of the lvs(8) command.

This returns a list of the logical volume device names (eg. /dev/VolGroup00/LogVol00).

See also guestfs_lvs_full, guestfs_list_filesystems.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.4)

guestfs_lvs_full

 struct guestfs_lvm_lv_list *
 guestfs_lvs_full (guestfs_h *g);

List all the logical volumes detected. This is the equivalent of the lvs(8) command. The "full" version includes all fields.

This function returns a struct guestfs_lvm_lv_list *, or NULL if there was an error. The caller must call guestfs_free_lvm_lv_list after use.

(Added in 0.4)

guestfs_lvuuid

 char *
 guestfs_lvuuid (guestfs_h *g,
                 const char *device);

This command returns the UUID of the LVM LV device.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.87)

guestfs_lxattrlist

 struct guestfs_xattr_list *
 guestfs_lxattrlist (guestfs_h *g,
                     const char *path,
                     char *const *names);

This call allows you to get the extended attributes of multiple files, where all files are in the directory path. names is the list of files from this directory.

On return you get a flat list of xattr structs which must be interpreted sequentially. The first xattr struct always has a zero-length attrname. attrval in this struct is zero-length to indicate there was an error doing lgetxattr for this file, or is a C string which is a decimal number (the number of following attributes for this file, which could be "0"). Then after the first xattr struct are the zero or more attributes for the first named file. This repeats for the second and subsequent files.

This call is intended for programs that want to efficiently list a directory contents without making many round-trips. See also guestfs_lstatlist for a similarly efficient call for getting standard stats.

This function returns a struct guestfs_xattr_list *, or NULL if there was an error. The caller must call guestfs_free_xattr_list after use.

(Added in 1.0.77)

guestfs_max_disks

 int
 guestfs_max_disks (guestfs_h *g);

Return the maximum number of disks that may be added to a handle (eg. by guestfs_add_drive_opts and similar calls).

This function was added in libguestfs 1.19.7. In previous versions of libguestfs the limit was 25.

See "MAXIMUM NUMBER OF DISKS" in guestfs(3) for additional information on this topic.

On error this function returns -1.

(Added in 1.19.7)

guestfs_md_create

 int
 guestfs_md_create (guestfs_h *g,
                    const char *name,
                    char *const *devices,
                    ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MD_CREATE_MISSINGBITMAP, int64_t missingbitmap,
 GUESTFS_MD_CREATE_NRDEVICES, int nrdevices,
 GUESTFS_MD_CREATE_SPARE, int spare,
 GUESTFS_MD_CREATE_CHUNK, int64_t chunk,
 GUESTFS_MD_CREATE_LEVEL, const char *level,

Create a Linux md (RAID) device named name on the devices in the list devices.

The optional parameters are:

missingbitmap

A bitmap of missing devices. If a bit is set it means that a missing device is added to the array. The least significant bit corresponds to the first device in the array.

As examples:

If devices = ["/dev/sda"] and missingbitmap = 0x1 then the resulting array would be [<missing>, "/dev/sda"].

If devices = ["/dev/sda"] and missingbitmap = 0x2 then the resulting array would be ["/dev/sda", <missing>].

This defaults to 0 (no missing devices).

The length of devices + the number of bits set in missingbitmap must equal nrdevices + spare.

nrdevices

The number of active RAID devices.

If not set, this defaults to the length of devices plus the number of bits set in missingbitmap.

spare

The number of spare devices.

If not set, this defaults to 0.

chunk

The chunk size in bytes.

level

The RAID level, which can be one of: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4, raid5, 5, raid6, 6, raid10, 10. Some of these are synonymous, and more levels may be added in future.

If not set, this defaults to raid1.

This function returns 0 on success or -1 on error.

(Added in 1.15.6)

guestfs_md_create_va

 int
 guestfs_md_create_va (guestfs_h *g,
                       const char *name,
                       char *const *devices,
                       va_list args);

This is the "va_list variant" of "guestfs_md_create".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_md_create_argv

 int
 guestfs_md_create_argv (guestfs_h *g,
                         const char *name,
                         char *const *devices,
                         const struct guestfs_md_create_argv *optargs);

This is the "argv variant" of "guestfs_md_create".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_md_detail

 char **
 guestfs_md_detail (guestfs_h *g,
                    const char *md);

This command exposes the output of 'mdadm -DY <md>'. The following fields are usually present in the returned hash. Other fields may also be present.

level

The raid level of the MD device.

devices

The number of underlying devices in the MD device.

metadata

The metadata version used.

uuid

The UUID of the MD device.

name

The name of the MD device.

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.15.6)

guestfs_md_stat

 struct guestfs_mdstat_list *
 guestfs_md_stat (guestfs_h *g,
                  const char *md);

This call returns a list of the underlying devices which make up the single software RAID array device md.

To get a list of software RAID devices, call guestfs_list_md_devices.

Each structure returned corresponds to one device along with additional status information:

mdstat_device

The name of the underlying device.

mdstat_index

The index of this device within the array.

mdstat_flags

Flags associated with this device. This is a string containing (in no specific order) zero or more of the following flags:

W

write-mostly

F

device is faulty

S

device is a RAID spare

R

replacement

This function returns a struct guestfs_mdstat_list *, or NULL if there was an error. The caller must call guestfs_free_mdstat_list after use.

(Added in 1.17.21)

guestfs_md_stop

 int
 guestfs_md_stop (guestfs_h *g,
                  const char *md);

This command deactivates the MD array named md. The device is stopped, but it is not destroyed or zeroed.

This function returns 0 on success or -1 on error.

(Added in 1.15.6)

guestfs_mkdir

 int
 guestfs_mkdir (guestfs_h *g,
                const char *path);

Create a directory named path.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_mkdir_mode

 int
 guestfs_mkdir_mode (guestfs_h *g,
                     const char *path,
                     int mode);

This command creates a directory, setting the initial permissions of the directory to mode.

For common Linux filesystems, the actual mode which is set will be mode & ~umask & 01777. Non-native-Linux filesystems may interpret the mode in other ways.

See also guestfs_mkdir, guestfs_umask

This function returns 0 on success or -1 on error.

(Added in 1.0.77)

guestfs_mkdir_p

 int
 guestfs_mkdir_p (guestfs_h *g,
                  const char *path);

Create a directory named path, creating any parent directories as necessary. This is like the mkdir -p shell command.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_mkdtemp

 char *
 guestfs_mkdtemp (guestfs_h *g,
                  const char *tmpl);

This command creates a temporary directory. The tmpl parameter should be a full pathname for the temporary directory name with the final six characters being "XXXXXX".

For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX", the second one being suitable for Windows filesystems.

The name of the temporary directory that was created is returned.

The temporary directory is created with mode 0700 and is owned by root.

The caller is responsible for deleting the temporary directory and its contents after use.

See also: mkdtemp(3)

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.54)

guestfs_mke2fs

 int
 guestfs_mke2fs (guestfs_h *g,
                 const char *device,
                 ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MKE2FS_BLOCKSCOUNT, int64_t blockscount,
 GUESTFS_MKE2FS_BLOCKSIZE, int64_t blocksize,
 GUESTFS_MKE2FS_FRAGSIZE, int64_t fragsize,
 GUESTFS_MKE2FS_BLOCKSPERGROUP, int64_t blockspergroup,
 GUESTFS_MKE2FS_NUMBEROFGROUPS, int64_t numberofgroups,
 GUESTFS_MKE2FS_BYTESPERINODE, int64_t bytesperinode,
 GUESTFS_MKE2FS_INODESIZE, int64_t inodesize,
 GUESTFS_MKE2FS_JOURNALSIZE, int64_t journalsize,
 GUESTFS_MKE2FS_NUMBEROFINODES, int64_t numberofinodes,
 GUESTFS_MKE2FS_STRIDESIZE, int64_t stridesize,
 GUESTFS_MKE2FS_STRIPEWIDTH, int64_t stripewidth,
 GUESTFS_MKE2FS_MAXONLINERESIZE, int64_t maxonlineresize,
 GUESTFS_MKE2FS_RESERVEDBLOCKSPERCENTAGE, int reservedblockspercentage,
 GUESTFS_MKE2FS_MMPUPDATEINTERVAL, int mmpupdateinterval,
 GUESTFS_MKE2FS_JOURNALDEVICE, const char *journaldevice,
 GUESTFS_MKE2FS_LABEL, const char *label,
 GUESTFS_MKE2FS_LASTMOUNTEDDIR, const char *lastmounteddir,
 GUESTFS_MKE2FS_CREATOROS, const char *creatoros,
 GUESTFS_MKE2FS_FSTYPE, const char *fstype,
 GUESTFS_MKE2FS_USAGETYPE, const char *usagetype,
 GUESTFS_MKE2FS_UUID, const char *uuid,
 GUESTFS_MKE2FS_FORCECREATE, int forcecreate,
 GUESTFS_MKE2FS_WRITESBANDGROUPONLY, int writesbandgrouponly,
 GUESTFS_MKE2FS_LAZYITABLEINIT, int lazyitableinit,
 GUESTFS_MKE2FS_LAZYJOURNALINIT, int lazyjournalinit,
 GUESTFS_MKE2FS_TESTFS, int testfs,
 GUESTFS_MKE2FS_DISCARD, int discard,
 GUESTFS_MKE2FS_QUOTATYPE, int quotatype,
 GUESTFS_MKE2FS_EXTENT, int extent,
 GUESTFS_MKE2FS_FILETYPE, int filetype,
 GUESTFS_MKE2FS_FLEXBG, int flexbg,
 GUESTFS_MKE2FS_HASJOURNAL, int hasjournal,
 GUESTFS_MKE2FS_JOURNALDEV, int journaldev,
 GUESTFS_MKE2FS_LARGEFILE, int largefile,
 GUESTFS_MKE2FS_QUOTA, int quota,
 GUESTFS_MKE2FS_RESIZEINODE, int resizeinode,
 GUESTFS_MKE2FS_SPARSESUPER, int sparsesuper,
 GUESTFS_MKE2FS_UNINITBG, int uninitbg,

mke2fs is used to create an ext2, ext3, or ext4 filesystem on device.

The optional blockscount is the size of the filesystem in blocks. If omitted it defaults to the size of device. Note if the filesystem is too small to contain a journal, mke2fs will silently create an ext2 filesystem instead.

This function returns 0 on success or -1 on error.

(Added in 1.19.44)

guestfs_mke2fs_va

 int
 guestfs_mke2fs_va (guestfs_h *g,
                    const char *device,
                    va_list args);

This is the "va_list variant" of "guestfs_mke2fs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mke2fs_argv

 int
 guestfs_mke2fs_argv (guestfs_h *g,
                      const char *device,
                      const struct guestfs_mke2fs_argv *optargs);

This is the "argv variant" of "guestfs_mke2fs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mke2fs_J

 int
 guestfs_mke2fs_J (guestfs_h *g,
                   const char *fstype,
                   int blocksize,
                   const char *device,
                   const char *journal);

This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This creates an ext2/3/4 filesystem on device with an external journal on journal. It is equivalent to the command:

 mke2fs -t fstype -b blocksize -J device=<journal> <device>

See also guestfs_mke2journal.

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mke2fs_JL

 int
 guestfs_mke2fs_JL (guestfs_h *g,
                    const char *fstype,
                    int blocksize,
                    const char *device,
                    const char *label);

This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This creates an ext2/3/4 filesystem on device with an external journal on the journal labeled label.

See also guestfs_mke2journal_L.

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mke2fs_JU

 int
 guestfs_mke2fs_JU (guestfs_h *g,
                    const char *fstype,
                    int blocksize,
                    const char *device,
                    const char *uuid);

This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This creates an ext2/3/4 filesystem on device with an external journal on the journal with UUID uuid.

See also guestfs_mke2journal_U.

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mke2journal

 int
 guestfs_mke2journal (guestfs_h *g,
                      int blocksize,
                      const char *device);

This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This creates an ext2 external journal on device. It is equivalent to the command:

 mke2fs -O journal_dev -b blocksize device

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mke2journal_L

 int
 guestfs_mke2journal_L (guestfs_h *g,
                        int blocksize,
                        const char *label,
                        const char *device);

This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This creates an ext2 external journal on device with label label.

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mke2journal_U

 int
 guestfs_mke2journal_U (guestfs_h *g,
                        int blocksize,
                        const char *uuid,
                        const char *device);

This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This creates an ext2 external journal on device with UUID uuid.

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mkfifo

 int
 guestfs_mkfifo (guestfs_h *g,
                 int mode,
                 const char *path);

This call creates a FIFO (named pipe) called path with mode mode. It is just a convenient wrapper around guestfs_mknod.

The mode actually set is affected by the umask.

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_mkfs

 int
 guestfs_mkfs (guestfs_h *g,
               const char *fstype,
               const char *device);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_mkfs_opts" with no optional arguments.

(Added in 0.8)

guestfs_mkfs_opts

 int
 guestfs_mkfs_opts (guestfs_h *g,
                    const char *fstype,
                    const char *device,
                    ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MKFS_OPTS_BLOCKSIZE, int blocksize,
 GUESTFS_MKFS_OPTS_FEATURES, const char *features,
 GUESTFS_MKFS_OPTS_INODE, int inode,
 GUESTFS_MKFS_OPTS_SECTORSIZE, int sectorsize,

This function creates a filesystem on device. The filesystem type is fstype, for example ext3.

The optional arguments are:

blocksize

The filesystem block size. Supported block sizes depend on the filesystem type, but typically they are 1024, 2048 or 4096 for Linux ext2/3 filesystems.

For VFAT and NTFS the blocksize parameter is treated as the requested cluster size.

For UFS block sizes, please see mkfs.ufs(8).

features

This passes the -O parameter to the external mkfs program.

For certain filesystem types, this allows extra filesystem features to be selected. See mke2fs(8) and mkfs.ufs(8) for more details.

You cannot use this optional parameter with the gfs or gfs2 filesystem type.

inode

This passes the -I parameter to the external mke2fs(8) program which sets the inode size (only for ext2/3/4 filesystems at present).

sectorsize

This passes the -S parameter to external mkfs.ufs(8) program, which sets sector size for ufs filesystem.

This function returns 0 on success or -1 on error.

(Added in 1.7.19)

guestfs_mkfs_opts_va

 int
 guestfs_mkfs_opts_va (guestfs_h *g,
                       const char *fstype,
                       const char *device,
                       va_list args);

This is the "va_list variant" of "guestfs_mkfs_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mkfs_opts_argv

 int
 guestfs_mkfs_opts_argv (guestfs_h *g,
                         const char *fstype,
                         const char *device,
                         const struct guestfs_mkfs_opts_argv *optargs);

This is the "argv variant" of "guestfs_mkfs_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mkfs_b

 int
 guestfs_mkfs_b (guestfs_h *g,
                 const char *fstype,
                 int blocksize,
                 const char *device);

This function is deprecated. In new code, use the "guestfs_mkfs" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This call is similar to guestfs_mkfs, but it allows you to control the block size of the resulting filesystem. Supported block sizes depend on the filesystem type, but typically they are 1024, 2048 or 4096 only.

For VFAT and NTFS the blocksize parameter is treated as the requested cluster size.

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mkfs_btrfs

 int
 guestfs_mkfs_btrfs (guestfs_h *g,
                     char *const *devices,
                     ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MKFS_BTRFS_ALLOCSTART, int64_t allocstart,
 GUESTFS_MKFS_BTRFS_BYTECOUNT, int64_t bytecount,
 GUESTFS_MKFS_BTRFS_DATATYPE, const char *datatype,
 GUESTFS_MKFS_BTRFS_LEAFSIZE, int leafsize,
 GUESTFS_MKFS_BTRFS_LABEL, const char *label,
 GUESTFS_MKFS_BTRFS_METADATA, const char *metadata,
 GUESTFS_MKFS_BTRFS_NODESIZE, int nodesize,
 GUESTFS_MKFS_BTRFS_SECTORSIZE, int sectorsize,

Create a btrfs filesystem, allowing all configurables to be set. For more information on the optional arguments, see mkfs.btrfs(8).

Since btrfs filesystems can span multiple devices, this takes a non-empty list of devices.

To create general filesystems, use guestfs_mkfs.

This function returns 0 on success or -1 on error.

(Added in 1.17.25)

guestfs_mkfs_btrfs_va

 int
 guestfs_mkfs_btrfs_va (guestfs_h *g,
                        char *const *devices,
                        va_list args);

This is the "va_list variant" of "guestfs_mkfs_btrfs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mkfs_btrfs_argv

 int
 guestfs_mkfs_btrfs_argv (guestfs_h *g,
                          char *const *devices,
                          const struct guestfs_mkfs_btrfs_argv *optargs);

This is the "argv variant" of "guestfs_mkfs_btrfs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mklost_and_found

 int
 guestfs_mklost_and_found (guestfs_h *g,
                           const char *mountpoint);

Make the lost+found directory, normally in the root directory of an ext2/3/4 filesystem. mountpoint is the directory under which we try to create the lost+found directory.

This function returns 0 on success or -1 on error.

(Added in 1.19.56)

guestfs_mkmountpoint

 int
 guestfs_mkmountpoint (guestfs_h *g,
                       const char *exemptpath);

guestfs_mkmountpoint and guestfs_rmmountpoint are specialized calls that can be used to create extra mountpoints before mounting the first filesystem.

These calls are only necessary in some very limited circumstances, mainly the case where you want to mount a mix of unrelated and/or read-only filesystems together.

For example, live CDs often contain a "Russian doll" nest of filesystems, an ISO outer layer, with a squashfs image inside, with an ext2/3 image inside that. You can unpack this as follows in guestfish:

 add-ro Fedora-11-i686-Live.iso
 run
 mkmountpoint /cd
 mkmountpoint /sqsh
 mkmountpoint /ext3fs
 mount /dev/sda /cd
 mount-loop /cd/LiveOS/squashfs.img /sqsh
 mount-loop /sqsh/LiveOS/ext3fs.img /ext3fs

The inner filesystem is now unpacked under the /ext3fs mountpoint.

guestfs_mkmountpoint is not compatible with guestfs_umount_all. You may get unexpected errors if you try to mix these calls. It is safest to manually unmount filesystems and remove mountpoints after use.

guestfs_umount_all unmounts filesystems by sorting the paths longest first, so for this to work for manual mountpoints, you must ensure that the innermost mountpoints have the longest pathnames, as in the example code above.

For more details see https://bugzilla.redhat.com/show_bug.cgi?id=599503

Autosync [see guestfs_set_autosync, this is set by default on handles] can cause guestfs_umount_all to be called when the handle is closed which can also trigger these issues.

This function returns 0 on success or -1 on error.

(Added in 1.0.62)

guestfs_mknod

 int
 guestfs_mknod (guestfs_h *g,
                int mode,
                int devmajor,
                int devminor,
                const char *path);

This call creates block or character special devices, or named pipes (FIFOs).

The mode parameter should be the mode, using the standard constants. devmajor and devminor are the device major and minor numbers, only used when creating block and character special devices.

Note that, just like mknod(2), the mode must be bitwise OR'd with S_IFBLK, S_IFCHR, S_IFIFO or S_IFSOCK (otherwise this call just creates a regular file). These constants are available in the standard Linux header files, or you can use guestfs_mknod_b, guestfs_mknod_c or guestfs_mkfifo which are wrappers around this command which bitwise OR in the appropriate constant for you.

The mode actually set is affected by the umask.

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_mknod_b

 int
 guestfs_mknod_b (guestfs_h *g,
                  int mode,
                  int devmajor,
                  int devminor,
                  const char *path);

This call creates a block device node called path with mode mode and device major/minor devmajor and devminor. It is just a convenient wrapper around guestfs_mknod.

The mode actually set is affected by the umask.

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_mknod_c

 int
 guestfs_mknod_c (guestfs_h *g,
                  int mode,
                  int devmajor,
                  int devminor,
                  const char *path);

This call creates a char device node called path with mode mode and device major/minor devmajor and devminor. It is just a convenient wrapper around guestfs_mknod.

The mode actually set is affected by the umask.

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_mkswap

 int
 guestfs_mkswap (guestfs_h *g,
                 const char *device);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_mkswap_opts" with no optional arguments.

(Added in 1.0.55)

guestfs_mkswap_opts

 int
 guestfs_mkswap_opts (guestfs_h *g,
                      const char *device,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MKSWAP_OPTS_LABEL, const char *label,
 GUESTFS_MKSWAP_OPTS_UUID, const char *uuid,

Create a Linux swap partition on device.

The option arguments label and uuid allow you to set the label and/or UUID of the new swap partition.

This function returns 0 on success or -1 on error.

(Added in 1.19.34)

guestfs_mkswap_opts_va

 int
 guestfs_mkswap_opts_va (guestfs_h *g,
                         const char *device,
                         va_list args);

This is the "va_list variant" of "guestfs_mkswap_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mkswap_opts_argv

 int
 guestfs_mkswap_opts_argv (guestfs_h *g,
                           const char *device,
                           const struct guestfs_mkswap_opts_argv *optargs);

This is the "argv variant" of "guestfs_mkswap_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mkswap_L

 int
 guestfs_mkswap_L (guestfs_h *g,
                   const char *label,
                   const char *device);

This function is deprecated. In new code, use the "guestfs_mkswap" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Create a swap partition on device with label label.

Note that you cannot attach a swap label to a block device (eg. /dev/sda), just to a partition. This appears to be a limitation of the kernel or swap tools.

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_mkswap_U

 int
 guestfs_mkswap_U (guestfs_h *g,
                   const char *uuid,
                   const char *device);

This function is deprecated. In new code, use the "guestfs_mkswap" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Create a swap partition on device with UUID uuid.

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_mkswap_file

 int
 guestfs_mkswap_file (guestfs_h *g,
                      const char *path);

Create a swap file.

This command just writes a swap file signature to an existing file. To create the file itself, use something like guestfs_fallocate.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_mktemp

 char *
 guestfs_mktemp (guestfs_h *g,
                 const char *tmpl,
                 ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MKTEMP_SUFFIX, const char *suffix,

This command creates a temporary file. The tmpl parameter should be a full pathname for the temporary directory name with the final six characters being "XXXXXX".

For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX", the second one being suitable for Windows filesystems.

The name of the temporary file that was created is returned.

The temporary file is created with mode 0600 and is owned by root.

The caller is responsible for deleting the temporary file after use.

If the optional suffix parameter is given, then the suffix (eg. .txt) is appended to the temporary name.

See also: guestfs_mkdtemp.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.19.53)

guestfs_mktemp_va

 char *
 guestfs_mktemp_va (guestfs_h *g,
                    const char *tmpl,
                    va_list args);

This is the "va_list variant" of "guestfs_mktemp".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mktemp_argv

 char *
 guestfs_mktemp_argv (guestfs_h *g,
                      const char *tmpl,
                      const struct guestfs_mktemp_argv *optargs);

This is the "argv variant" of "guestfs_mktemp".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_modprobe

 int
 guestfs_modprobe (guestfs_h *g,
                   const char *modulename);

This loads a kernel module in the appliance.

The kernel module must have been whitelisted when libguestfs was built (see appliance/kmod.whitelist.in in the source).

This function returns 0 on success or -1 on error.

(Added in 1.0.68)

guestfs_mount

 int
 guestfs_mount (guestfs_h *g,
                const char *mountable,
                const char *mountpoint);

Mount a guest disk at a position in the filesystem. Block devices are named /dev/sda, /dev/sdb and so on, as they were added to the guest. If those block devices contain partitions, they will have the usual names (eg. /dev/sda1). Also LVM /dev/VG/LV-style names can be used, or 'mountable' strings returned by guestfs_list_filesystems or guestfs_inspect_get_mountpoints.

The rules are the same as for mount(2): A filesystem must first be mounted on / before others can be mounted. Other filesystems can only be mounted on directories which already exist.

The mounted filesystem is writable, if we have sufficient permissions on the underlying device.

Before libguestfs 1.13.16, this call implicitly added the options sync and noatime. The sync option greatly slowed writes and caused many problems for users. If your program might need to work with older versions of libguestfs, use guestfs_mount_options instead (using an empty string for the first parameter if you don't want any options).

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_mount_9p

 int
 guestfs_mount_9p (guestfs_h *g,
                   const char *mounttag,
                   const char *mountpoint,
                   ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MOUNT_9P_OPTIONS, const char *options,

Mount the virtio-9p filesystem with the tag mounttag on the directory mountpoint.

If required, trans=virtio will be automatically added to the options. Any other options required can be passed in the optional options parameter.

This function returns 0 on success or -1 on error.

(Added in 1.11.12)

guestfs_mount_9p_va

 int
 guestfs_mount_9p_va (guestfs_h *g,
                      const char *mounttag,
                      const char *mountpoint,
                      va_list args);

This is the "va_list variant" of "guestfs_mount_9p".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mount_9p_argv

 int
 guestfs_mount_9p_argv (guestfs_h *g,
                        const char *mounttag,
                        const char *mountpoint,
                        const struct guestfs_mount_9p_argv *optargs);

This is the "argv variant" of "guestfs_mount_9p".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mount_local

 int
 guestfs_mount_local (guestfs_h *g,
                      const char *localmountpoint,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_MOUNT_LOCAL_READONLY, int readonly,
 GUESTFS_MOUNT_LOCAL_OPTIONS, const char *options,
 GUESTFS_MOUNT_LOCAL_CACHETIMEOUT, int cachetimeout,
 GUESTFS_MOUNT_LOCAL_DEBUGCALLS, int debugcalls,

This call exports the libguestfs-accessible filesystem to a local mountpoint (directory) called localmountpoint. Ordinary reads and writes to files and directories under localmountpoint are redirected through libguestfs.

If the optional readonly flag is set to true, then writes to the filesystem return error EROFS.

options is a comma-separated list of mount options. See guestmount(1) for some useful options.

cachetimeout sets the timeout (in seconds) for cached directory entries. The default is 60 seconds. See guestmount(1) for further information.

If debugcalls is set to true, then additional debugging information is generated for every FUSE call.

When guestfs_mount_local returns, the filesystem is ready, but is not processing requests (access to it will block). You have to call guestfs_mount_local_run to run the main loop.

See "MOUNT LOCAL" in guestfs(3) for full documentation.

This function returns 0 on success or -1 on error.

(Added in 1.17.22)

guestfs_mount_local_va

 int
 guestfs_mount_local_va (guestfs_h *g,
                         const char *localmountpoint,
                         va_list args);

This is the "va_list variant" of "guestfs_mount_local".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mount_local_argv

 int
 guestfs_mount_local_argv (guestfs_h *g,
                           const char *localmountpoint,
                           const struct guestfs_mount_local_argv *optargs);

This is the "argv variant" of "guestfs_mount_local".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_mount_local_run

 int
 guestfs_mount_local_run (guestfs_h *g);

Run the main loop which translates kernel calls to libguestfs calls.

This should only be called after guestfs_mount_local returns successfully. The call will not return until the filesystem is unmounted.

Note you must not make concurrent libguestfs calls on the same handle from another thread.

You may call this from a different thread than the one which called guestfs_mount_local, subject to the usual rules for threads and libguestfs (see "MULTIPLE HANDLES AND MULTIPLE THREADS" in guestfs(3)).

See "MOUNT LOCAL" in guestfs(3) for full documentation.

This function returns 0 on success or -1 on error.

(Added in 1.17.22)

guestfs_mount_loop

 int
 guestfs_mount_loop (guestfs_h *g,
                     const char *file,
                     const char *mountpoint);

This command lets you mount file (a filesystem image in a file) on a mount point. It is entirely equivalent to the command mount -o loop file mountpoint.

This function returns 0 on success or -1 on error.

(Added in 1.0.54)

guestfs_mount_options

 int
 guestfs_mount_options (guestfs_h *g,
                        const char *options,
                        const char *mountable,
                        const char *mountpoint);

This is the same as the guestfs_mount command, but it allows you to set the mount options as for the mount(8) -o flag.

If the options parameter is an empty string, then no options are passed (all options default to whatever the filesystem uses).

This function returns 0 on success or -1 on error.

(Added in 1.0.10)

guestfs_mount_ro

 int
 guestfs_mount_ro (guestfs_h *g,
                   const char *mountable,
                   const char *mountpoint);

This is the same as the guestfs_mount command, but it mounts the filesystem with the read-only (-o ro) flag.

This function returns 0 on success or -1 on error.

(Added in 1.0.10)

guestfs_mount_vfs

 int
 guestfs_mount_vfs (guestfs_h *g,
                    const char *options,
                    const char *vfstype,
                    const char *mountable,
                    const char *mountpoint);

This is the same as the guestfs_mount command, but it allows you to set both the mount options and the vfstype as for the mount(8) -o and -t flags.

This function returns 0 on success or -1 on error.

(Added in 1.0.10)

guestfs_mountpoints

 char **
 guestfs_mountpoints (guestfs_h *g);

This call is similar to guestfs_mounts. That call returns a list of devices. This one returns a hash table (map) of device name to directory where the device is mounted.

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 1.0.62)

guestfs_mounts

 char **
 guestfs_mounts (guestfs_h *g);

This returns the list of currently mounted filesystems. It returns the list of devices (eg. /dev/sda1, /dev/VG/LV).

Some internal mounts are not shown.

See also: guestfs_mountpoints

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.8)

guestfs_mv

 int
 guestfs_mv (guestfs_h *g,
             const char *src,
             const char *dest);

This moves a file from src to dest where dest is either a destination filename or destination directory.

See also: guestfs_rename.

This function returns 0 on success or -1 on error.

(Added in 1.0.18)

guestfs_nr_devices

 int
 guestfs_nr_devices (guestfs_h *g);

This returns the number of whole block devices that were added. This is the same as the number of devices that would be returned if you called guestfs_list_devices.

To find out the maximum number of devices that could be added, call guestfs_max_disks.

On error this function returns -1.

(Added in 1.19.15)

guestfs_ntfs_3g_probe

 int
 guestfs_ntfs_3g_probe (guestfs_h *g,
                        int rw,
                        const char *device);

This command runs the ntfs-3g.probe(8) command which probes an NTFS device for mountability. (Not all NTFS volumes can be mounted read-write, and some cannot be mounted at all).

rw is a boolean flag. Set it to true if you want to test if the volume can be mounted read-write. Set it to false if you want to test if the volume can be mounted read-only.

The return value is an integer which 0 if the operation would succeed, or some non-zero value documented in the ntfs-3g.probe(8) manual page.

On error this function returns -1.

(Added in 1.0.43)

guestfs_ntfsclone_in

 int
 guestfs_ntfsclone_in (guestfs_h *g,
                       const char *backupfile,
                       const char *device);

Restore the backupfile (from a previous call to guestfs_ntfsclone_out) to device, overwriting any existing contents of this device.

This function returns 0 on success or -1 on error.

(Added in 1.17.9)

guestfs_ntfsclone_out

 int
 guestfs_ntfsclone_out (guestfs_h *g,
                        const char *device,
                        const char *backupfile,
                        ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_NTFSCLONE_OUT_METADATAONLY, int metadataonly,
 GUESTFS_NTFSCLONE_OUT_RESCUE, int rescue,
 GUESTFS_NTFSCLONE_OUT_IGNOREFSCHECK, int ignorefscheck,
 GUESTFS_NTFSCLONE_OUT_PRESERVETIMESTAMPS, int preservetimestamps,
 GUESTFS_NTFSCLONE_OUT_FORCE, int force,

Stream the NTFS filesystem device to the local file backupfile. The format used for the backup file is a special format used by the ntfsclone(8) tool.

If the optional metadataonly flag is true, then only the metadata is saved, losing all the user data (this is useful for diagnosing some filesystem problems).

The optional rescue, ignorefscheck, preservetimestamps and force flags have precise meanings detailed in the ntfsclone(8) man page.

Use guestfs_ntfsclone_in to restore the file back to a libguestfs device.

This function returns 0 on success or -1 on error.

(Added in 1.17.9)

guestfs_ntfsclone_out_va

 int
 guestfs_ntfsclone_out_va (guestfs_h *g,
                           const char *device,
                           const char *backupfile,
                           va_list args);

This is the "va_list variant" of "guestfs_ntfsclone_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_ntfsclone_out_argv

 int
 guestfs_ntfsclone_out_argv (guestfs_h *g,
                             const char *device,
                             const char *backupfile,
                             const struct guestfs_ntfsclone_out_argv *optargs);

This is the "argv variant" of "guestfs_ntfsclone_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_ntfsfix

 int
 guestfs_ntfsfix (guestfs_h *g,
                  const char *device,
                  ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_NTFSFIX_CLEARBADSECTORS, int clearbadsectors,

This command repairs some fundamental NTFS inconsistencies, resets the NTFS journal file, and schedules an NTFS consistency check for the first boot into Windows.

This is not an equivalent of Windows chkdsk. It does not scan the filesystem for inconsistencies.

The optional clearbadsectors flag clears the list of bad sectors. This is useful after cloning a disk with bad sectors to a new disk.

This function returns 0 on success or -1 on error.

(Added in 1.17.9)

guestfs_ntfsfix_va

 int
 guestfs_ntfsfix_va (guestfs_h *g,
                     const char *device,
                     va_list args);

This is the "va_list variant" of "guestfs_ntfsfix".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_ntfsfix_argv

 int
 guestfs_ntfsfix_argv (guestfs_h *g,
                       const char *device,
                       const struct guestfs_ntfsfix_argv *optargs);

This is the "argv variant" of "guestfs_ntfsfix".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_ntfsresize

 int
 guestfs_ntfsresize (guestfs_h *g,
                     const char *device);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_ntfsresize_opts" with no optional arguments.

(Added in 1.3.2)

guestfs_ntfsresize_opts

 int
 guestfs_ntfsresize_opts (guestfs_h *g,
                          const char *device,
                          ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_NTFSRESIZE_OPTS_SIZE, int64_t size,
 GUESTFS_NTFSRESIZE_OPTS_FORCE, int force,

This command resizes an NTFS filesystem, expanding or shrinking it to the size of the underlying device.

The optional parameters are:

size

The new size (in bytes) of the filesystem. If omitted, the filesystem is resized to fit the container (eg. partition).

force

If this option is true, then force the resize of the filesystem even if the filesystem is marked as requiring a consistency check.

After the resize operation, the filesystem is always marked as requiring a consistency check (for safety). You have to boot into Windows to perform this check and clear this condition. If you don't set the force option then it is not possible to call guestfs_ntfsresize multiple times on a single filesystem without booting into Windows between each resize.

See also ntfsresize(8).

This function returns 0 on success or -1 on error.

(Added in 1.11.15)

guestfs_ntfsresize_opts_va

 int
 guestfs_ntfsresize_opts_va (guestfs_h *g,
                             const char *device,
                             va_list args);

This is the "va_list variant" of "guestfs_ntfsresize_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_ntfsresize_opts_argv

 int
 guestfs_ntfsresize_opts_argv (guestfs_h *g,
                               const char *device,
                               const struct guestfs_ntfsresize_opts_argv *optargs);

This is the "argv variant" of "guestfs_ntfsresize_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_ntfsresize_size

 int
 guestfs_ntfsresize_size (guestfs_h *g,
                          const char *device,
                          int64_t size);

This function is deprecated. In new code, use the "guestfs_ntfsresize" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command is the same as guestfs_ntfsresize except that it allows you to specify the new size (in bytes) explicitly.

This function returns 0 on success or -1 on error.

(Added in 1.3.14)

guestfs_parse_environment

 int
 guestfs_parse_environment (guestfs_h *g);

Parse the program's environment and set flags in the handle accordingly. For example if LIBGUESTFS_DEBUG=1 then the 'verbose' flag is set in the handle.

Most programs do not need to call this. It is done implicitly when you call guestfs_create.

See "ENVIRONMENT VARIABLES" in guestfs(3) for a list of environment variables that can affect libguestfs handles. See also "guestfs_create_flags" in guestfs(3), and guestfs_parse_environment_list.

This function returns 0 on success or -1 on error.

(Added in 1.19.53)

guestfs_parse_environment_list

 int
 guestfs_parse_environment_list (guestfs_h *g,
                                 char *const *environment);

Parse the list of strings in the argument environment and set flags in the handle accordingly. For example if LIBGUESTFS_DEBUG=1 is a string in the list, then the 'verbose' flag is set in the handle.

This is the same as guestfs_parse_environment except that it parses an explicit list of strings instead of the program's environment.

This function returns 0 on success or -1 on error.

(Added in 1.19.53)

guestfs_part_add

 int
 guestfs_part_add (guestfs_h *g,
                   const char *device,
                   const char *prlogex,
                   int64_t startsect,
                   int64_t endsect);

This command adds a partition to device. If there is no partition table on the device, call guestfs_part_init first.

The prlogex parameter is the type of partition. Normally you should pass p or primary here, but MBR partition tables also support l (or logical) and e (or extended) partition types.

startsect and endsect are the start and end of the partition in sectors. endsect may be negative, which means it counts backwards from the end of the disk (-1 is the last sector).

Creating a partition which covers the whole disk is not so easy. Use guestfs_part_disk to do that.

This function returns 0 on success or -1 on error.

(Added in 1.0.78)

guestfs_part_del

 int
 guestfs_part_del (guestfs_h *g,
                   const char *device,
                   int partnum);

This command deletes the partition numbered partnum on device.

Note that in the case of MBR partitioning, deleting an extended partition also deletes any logical partitions it contains.

This function returns 0 on success or -1 on error.

(Added in 1.3.2)

guestfs_part_disk

 int
 guestfs_part_disk (guestfs_h *g,
                    const char *device,
                    const char *parttype);

This command is simply a combination of guestfs_part_init followed by guestfs_part_add to create a single primary partition covering the whole disk.

parttype is the partition table type, usually mbr or gpt, but other possible values are described in guestfs_part_init.

This function returns 0 on success or -1 on error.

(Added in 1.0.78)

guestfs_part_get_bootable

 int
 guestfs_part_get_bootable (guestfs_h *g,
                            const char *device,
                            int partnum);

This command returns true if the partition partnum on device has the bootable flag set.

See also guestfs_part_set_bootable.

This function returns a C truth value on success or -1 on error.

(Added in 1.3.2)

guestfs_part_get_gpt_type

 char *
 guestfs_part_get_gpt_type (guestfs_h *g,
                            const char *device,
                            int partnum);

Return the type GUID of numbered GPT partition partnum. For MBR partitions, return an appropriate GUID corresponding to the MBR type. Behaviour is undefined for other partition types.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.21.1)

guestfs_part_get_mbr_id

 int
 guestfs_part_get_mbr_id (guestfs_h *g,
                          const char *device,
                          int partnum);

Returns the MBR type byte (also known as the ID byte) from the numbered partition partnum.

Note that only MBR (old DOS-style) partitions have type bytes. You will get undefined results for other partition table types (see guestfs_part_get_parttype).

On error this function returns -1.

(Added in 1.3.2)

guestfs_part_get_name

 char *
 guestfs_part_get_name (guestfs_h *g,
                        const char *device,
                        int partnum);

This gets the partition name on partition numbered partnum on device device. Note that partitions are numbered from 1.

The partition name can only be read on certain types of partition table. This works on gpt but not on mbr partitions.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.25.33)

guestfs_part_get_parttype

 char *
 guestfs_part_get_parttype (guestfs_h *g,
                            const char *device);

This command examines the partition table on device and returns the partition table type (format) being used.

Common return values include: msdos (a DOS/Windows style MBR partition table), gpt (a GPT/EFI-style partition table). Other values are possible, although unusual. See guestfs_part_init for a full list.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.78)

guestfs_part_init

 int
 guestfs_part_init (guestfs_h *g,
                    const char *device,
                    const char *parttype);

This creates an empty partition table on device of one of the partition types listed below. Usually parttype should be either msdos or gpt (for large disks).

Initially there are no partitions. Following this, you should call guestfs_part_add for each partition required.

Possible values for parttype are:

efi
gpt

Intel EFI / GPT partition table.

This is recommended for >= 2 TB partitions that will be accessed from Linux and Intel-based Mac OS X. It also has limited backwards compatibility with the mbr format.

mbr
msdos

The standard PC "Master Boot Record" (MBR) format used by MS-DOS and Windows. This partition type will only work for device sizes up to 2 TB. For large disks we recommend using gpt.

Other partition table types that may work but are not supported include:

aix

AIX disk labels.

amiga
rdb

Amiga "Rigid Disk Block" format.

bsd

BSD disk labels.

dasd

DASD, used on IBM mainframes.

dvh

MIPS/SGI volumes.

mac

Old Mac partition format. Modern Macs use gpt.

pc98

NEC PC-98 format, common in Japan apparently.

sun

Sun disk labels.

This function returns 0 on success or -1 on error.

(Added in 1.0.78)

guestfs_part_list

 struct guestfs_partition_list *
 guestfs_part_list (guestfs_h *g,
                    const char *device);

This command parses the partition table on device and returns the list of partitions found.

The fields in the returned structure are:

part_num

Partition number, counting from 1.

part_start

Start of the partition in bytes. To get sectors you have to divide by the device's sector size, see guestfs_blockdev_getss.

part_end

End of the partition in bytes.

part_size

Size of the partition in bytes.

This function returns a struct guestfs_partition_list *, or NULL if there was an error. The caller must call guestfs_free_partition_list after use.

(Added in 1.0.78)

guestfs_part_set_bootable

 int
 guestfs_part_set_bootable (guestfs_h *g,
                            const char *device,
                            int partnum,
                            int bootable);

This sets the bootable flag on partition numbered partnum on device device. Note that partitions are numbered from 1.

The bootable flag is used by some operating systems (notably Windows) to determine which partition to boot from. It is by no means universally recognized.

This function returns 0 on success or -1 on error.

(Added in 1.0.78)

guestfs_part_set_gpt_type

 int
 guestfs_part_set_gpt_type (guestfs_h *g,
                            const char *device,
                            int partnum,
                            const char *guid);

Set the type GUID of numbered GPT partition partnum to guid. Return an error if the partition table of device isn't GPT, or if guid is not a valid GUID.

See http://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs for a useful list of type GUIDs.

This function returns 0 on success or -1 on error.

(Added in 1.21.1)

guestfs_part_set_mbr_id

 int
 guestfs_part_set_mbr_id (guestfs_h *g,
                          const char *device,
                          int partnum,
                          int idbyte);

Sets the MBR type byte (also known as the ID byte) of the numbered partition partnum to idbyte. Note that the type bytes quoted in most documentation are in fact hexadecimal numbers, but usually documented without any leading "0x" which might be confusing.

Note that only MBR (old DOS-style) partitions have type bytes. You will get undefined results for other partition table types (see guestfs_part_get_parttype).

This function returns 0 on success or -1 on error.

(Added in 1.3.2)

guestfs_part_set_name

 int
 guestfs_part_set_name (guestfs_h *g,
                        const char *device,
                        int partnum,
                        const char *name);

This sets the partition name on partition numbered partnum on device device. Note that partitions are numbered from 1.

The partition name can only be set on certain types of partition table. This works on gpt but not on mbr partitions.

This function returns 0 on success or -1 on error.

(Added in 1.0.78)

guestfs_part_to_dev

 char *
 guestfs_part_to_dev (guestfs_h *g,
                      const char *partition);

This function takes a partition name (eg. "/dev/sdb1") and removes the partition number, returning the device name (eg. "/dev/sdb").

The named partition must exist, for example as a string returned from guestfs_list_partitions.

See also guestfs_part_to_partnum, guestfs_device_index.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.5.15)

guestfs_part_to_partnum

 int
 guestfs_part_to_partnum (guestfs_h *g,
                          const char *partition);

This function takes a partition name (eg. "/dev/sdb1") and returns the partition number (eg. 1).

The named partition must exist, for example as a string returned from guestfs_list_partitions.

See also guestfs_part_to_dev.

On error this function returns -1.

(Added in 1.13.25)

guestfs_ping_daemon

 int
 guestfs_ping_daemon (guestfs_h *g);

This is a test probe into the guestfs daemon running inside the hypervisor. Calling this function checks that the daemon responds to the ping message, without affecting the daemon or attached block device(s) in any other way.

This function returns 0 on success or -1 on error.

(Added in 1.0.18)

guestfs_pread

 char *
 guestfs_pread (guestfs_h *g,
                const char *path,
                int count,
                int64_t offset,
                size_t *size_r);

This command lets you read part of a file. It reads count bytes of the file, starting at offset, from file path.

This may read fewer bytes than requested. For further details see the pread(2) system call.

See also guestfs_pwrite, guestfs_pread_device.

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.77)

guestfs_pread_device

 char *
 guestfs_pread_device (guestfs_h *g,
                       const char *device,
                       int count,
                       int64_t offset,
                       size_t *size_r);

This command lets you read part of a block device. It reads count bytes of device, starting at offset.

This may read fewer bytes than requested. For further details see the pread(2) system call.

See also guestfs_pread.

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.5.21)

guestfs_pvchange_uuid

 int
 guestfs_pvchange_uuid (guestfs_h *g,
                        const char *device);

Generate a new random UUID for the physical volume device.

This function returns 0 on success or -1 on error.

(Added in 1.19.26)

guestfs_pvchange_uuid_all

 int
 guestfs_pvchange_uuid_all (guestfs_h *g);

Generate new random UUIDs for all physical volumes.

This function returns 0 on success or -1 on error.

(Added in 1.19.26)

guestfs_pvcreate

 int
 guestfs_pvcreate (guestfs_h *g,
                   const char *device);

This creates an LVM physical volume on the named device, where device should usually be a partition name such as /dev/sda1.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_pvremove

 int
 guestfs_pvremove (guestfs_h *g,
                   const char *device);

This wipes a physical volume device so that LVM will no longer recognise it.

The implementation uses the pvremove command which refuses to wipe physical volumes that contain any volume groups, so you have to remove those first.

This function returns 0 on success or -1 on error.

(Added in 1.0.13)

guestfs_pvresize

 int
 guestfs_pvresize (guestfs_h *g,
                   const char *device);

This resizes (expands or shrinks) an existing LVM physical volume to match the new size of the underlying device.

This function returns 0 on success or -1 on error.

(Added in 1.0.26)

guestfs_pvresize_size

 int
 guestfs_pvresize_size (guestfs_h *g,
                        const char *device,
                        int64_t size);

This command is the same as guestfs_pvresize except that it allows you to specify the new size (in bytes) explicitly.

This function returns 0 on success or -1 on error.

(Added in 1.3.14)

guestfs_pvs

 char **
 guestfs_pvs (guestfs_h *g);

List all the physical volumes detected. This is the equivalent of the pvs(8) command.

This returns a list of just the device names that contain PVs (eg. /dev/sda2).

See also guestfs_pvs_full.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.4)

guestfs_pvs_full

 struct guestfs_lvm_pv_list *
 guestfs_pvs_full (guestfs_h *g);

List all the physical volumes detected. This is the equivalent of the pvs(8) command. The "full" version includes all fields.

This function returns a struct guestfs_lvm_pv_list *, or NULL if there was an error. The caller must call guestfs_free_lvm_pv_list after use.

(Added in 0.4)

guestfs_pvuuid

 char *
 guestfs_pvuuid (guestfs_h *g,
                 const char *device);

This command returns the UUID of the LVM PV device.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.87)

guestfs_pwrite

 int
 guestfs_pwrite (guestfs_h *g,
                 const char *path,
                 const char *content,
                 size_t content_size,
                 int64_t offset);

This command writes to part of a file. It writes the data buffer content to the file path starting at offset offset.

This command implements the pwrite(2) system call, and like that system call it may not write the full data requested. The return value is the number of bytes that were actually written to the file. This could even be 0, although short writes are unlikely for regular files in ordinary circumstances.

See also guestfs_pread, guestfs_pwrite_device.

On error this function returns -1.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.3.14)

guestfs_pwrite_device

 int
 guestfs_pwrite_device (guestfs_h *g,
                        const char *device,
                        const char *content,
                        size_t content_size,
                        int64_t offset);

This command writes to part of a device. It writes the data buffer content to device starting at offset offset.

This command implements the pwrite(2) system call, and like that system call it may not write the full data requested (although short writes to disk devices and partitions are probably impossible with standard Linux kernels).

See also guestfs_pwrite.

On error this function returns -1.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.5.20)

guestfs_read_file

 char *
 guestfs_read_file (guestfs_h *g,
                    const char *path,
                    size_t *size_r);

This calls returns the contents of the file path as a buffer.

Unlike guestfs_cat, this function can correctly handle files that contain embedded ASCII NUL characters.

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

(Added in 1.0.63)

guestfs_read_lines

 char **
 guestfs_read_lines (guestfs_h *g,
                     const char *path);

Return the contents of the file named path.

The file contents are returned as a list of lines. Trailing LF and CRLF character sequences are not returned.

Note that this function cannot correctly handle binary files (specifically, files containing \0 character which is treated as end of string). For those you need to use the guestfs_read_file function and split the buffer into lines yourself.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.7)

guestfs_readdir

 struct guestfs_dirent_list *
 guestfs_readdir (guestfs_h *g,
                  const char *dir);

This returns the list of directory entries in directory dir.

All entries in the directory are returned, including . and ... The entries are not sorted, but returned in the same order as the underlying filesystem.

Also this call returns basic file type information about each file. The ftyp field will contain one of the following characters:

'b'

Block special

'c'

Char special

'd'

Directory

'f'

FIFO (named pipe)

'l'

Symbolic link

'r'

Regular file

's'

Socket

'u'

Unknown file type

'?'

The readdir(3) call returned a d_type field with an unexpected value

This function is primarily intended for use by programs. To get a simple list of names, use guestfs_ls. To get a printable directory for human consumption, use guestfs_ll.

This function returns a struct guestfs_dirent_list *, or NULL if there was an error. The caller must call guestfs_free_dirent_list after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.55)

 char *
 guestfs_readlink (guestfs_h *g,
                   const char *path);

This command reads the target of a symbolic link.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.66)

 char **
 guestfs_readlinklist (guestfs_h *g,
                       const char *path,
                       char *const *names);

This call allows you to do a readlink operation on multiple files, where all files are in the directory path. names is the list of files from this directory.

On return you get a list of strings, with a one-to-one correspondence to the names list. Each string is the value of the symbolic link.

If the readlink(2) operation fails on any name, then the corresponding result string is the empty string "". However the whole operation is completed even if there were readlink(2) errors, and so you can call this function with names where you don't know if they are symbolic links already (albeit slightly less efficient).

This call is intended for programs that want to efficiently list a directory contents without making many round-trips.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.77)

guestfs_realpath

 char *
 guestfs_realpath (guestfs_h *g,
                   const char *path);

Return the canonicalized absolute pathname of path. The returned path has no ., .. or symbolic link path elements.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.66)

guestfs_remount

 int
 guestfs_remount (guestfs_h *g,
                  const char *mountpoint,
                  ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_REMOUNT_RW, int rw,

This call allows you to change the rw (readonly/read-write) flag on an already mounted filesystem at mountpoint, converting a readonly filesystem to be read-write, or vice-versa.

Note that at the moment you must supply the "optional" rw parameter. In future we may allow other flags to be adjusted.

This function returns 0 on success or -1 on error.

(Added in 1.23.2)

guestfs_remount_va

 int
 guestfs_remount_va (guestfs_h *g,
                     const char *mountpoint,
                     va_list args);

This is the "va_list variant" of "guestfs_remount".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_remount_argv

 int
 guestfs_remount_argv (guestfs_h *g,
                       const char *mountpoint,
                       const struct guestfs_remount_argv *optargs);

This is the "argv variant" of "guestfs_remount".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_remove_drive

 int
 guestfs_remove_drive (guestfs_h *g,
                       const char *label);

This function is conceptually the opposite of guestfs_add_drive_opts. It removes the drive that was previously added with label label.

Note that in order to remove drives, you have to add them with labels (see the optional label argument to guestfs_add_drive_opts). If you didn't use a label, then they cannot be removed.

You can call this function before or after launching the handle. If called after launch, if the backend supports it, we try to hot unplug the drive: see "HOTPLUGGING" in guestfs(3). The disk must not be in use (eg. mounted) when you do this. We try to detect if the disk is in use and stop you from doing this.

This function returns 0 on success or -1 on error.

(Added in 1.19.49)

guestfs_removexattr

 int
 guestfs_removexattr (guestfs_h *g,
                      const char *xattr,
                      const char *path);

This call removes the extended attribute named xattr of the file path.

See also: guestfs_lremovexattr, attr(5).

This function returns 0 on success or -1 on error.

(Added in 1.0.59)

guestfs_rename

 int
 guestfs_rename (guestfs_h *g,
                 const char *oldpath,
                 const char *newpath);

Rename a file to a new place on the same filesystem. This is the same as the Linux rename(2) system call. In most cases you are better to use guestfs_mv instead.

This function returns 0 on success or -1 on error.

(Added in 1.21.5)

guestfs_resize2fs

 int
 guestfs_resize2fs (guestfs_h *g,
                    const char *device);

This resizes an ext2, ext3 or ext4 filesystem to match the size of the underlying device.

See also "RESIZE2FS ERRORS" in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.0.27)

guestfs_resize2fs_M

 int
 guestfs_resize2fs_M (guestfs_h *g,
                      const char *device);

This command is the same as guestfs_resize2fs, but the filesystem is resized to its minimum size. This works like the -M option to the resize2fs command.

To get the resulting size of the filesystem you should call guestfs_tune2fs_l and read the Block size and Block count values. These two numbers, multiplied together, give the resulting size of the minimal filesystem in bytes.

See also "RESIZE2FS ERRORS" in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.9.4)

guestfs_resize2fs_size

 int
 guestfs_resize2fs_size (guestfs_h *g,
                         const char *device,
                         int64_t size);

This command is the same as guestfs_resize2fs except that it allows you to specify the new size (in bytes) explicitly.

See also "RESIZE2FS ERRORS" in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.3.14)

guestfs_rm

 int
 guestfs_rm (guestfs_h *g,
             const char *path);

Remove the single file path.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_rm_f

 int
 guestfs_rm_f (guestfs_h *g,
               const char *path);

Remove the file path.

If the file doesn't exist, that error is ignored. (Other errors, eg. I/O errors or bad paths, are not ignored)

This call cannot remove directories. Use guestfs_rmdir to remove an empty directory, or guestfs_rm_rf to remove directories recursively.

This function returns 0 on success or -1 on error.

(Added in 1.19.42)

guestfs_rm_rf

 int
 guestfs_rm_rf (guestfs_h *g,
                const char *path);

Remove the file or directory path, recursively removing the contents if its a directory. This is like the rm -rf shell command.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_rmdir

 int
 guestfs_rmdir (guestfs_h *g,
                const char *path);

Remove the single directory path.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_rmmountpoint

 int
 guestfs_rmmountpoint (guestfs_h *g,
                       const char *exemptpath);

This calls removes a mountpoint that was previously created with guestfs_mkmountpoint. See guestfs_mkmountpoint for full details.

This function returns 0 on success or -1 on error.

(Added in 1.0.62)

guestfs_rsync

 int
 guestfs_rsync (guestfs_h *g,
                const char *src,
                const char *dest,
                ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_RSYNC_ARCHIVE, int archive,
 GUESTFS_RSYNC_DELETEDEST, int deletedest,

This call may be used to copy or synchronize two directories under the same libguestfs handle. This uses the rsync(1) program which uses a fast algorithm that avoids copying files unnecessarily.

src and dest are the source and destination directories. Files are copied from src to dest.

The optional arguments are:

archive

Turns on archive mode. This is the same as passing the --archive flag to rsync.

deletedest

Delete files at the destination that do not exist at the source.

This function returns 0 on success or -1 on error.

(Added in 1.19.29)

guestfs_rsync_va

 int
 guestfs_rsync_va (guestfs_h *g,
                   const char *src,
                   const char *dest,
                   va_list args);

This is the "va_list variant" of "guestfs_rsync".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_rsync_argv

 int
 guestfs_rsync_argv (guestfs_h *g,
                     const char *src,
                     const char *dest,
                     const struct guestfs_rsync_argv *optargs);

This is the "argv variant" of "guestfs_rsync".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_rsync_in

 int
 guestfs_rsync_in (guestfs_h *g,
                   const char *remote,
                   const char *dest,
                   ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_RSYNC_IN_ARCHIVE, int archive,
 GUESTFS_RSYNC_IN_DELETEDEST, int deletedest,

This call may be used to copy or synchronize the filesystem on the host or on a remote computer with the filesystem within libguestfs. This uses the rsync(1) program which uses a fast algorithm that avoids copying files unnecessarily.

This call only works if the network is enabled. See guestfs_set_network or the --network option to various tools like guestfish(1).

Files are copied from the remote server and directory specified by remote to the destination directory dest.

The format of the remote server string is defined by rsync(1). Note that there is no way to supply a password or passphrase so the target must be set up not to require one.

The optional arguments are the same as those of guestfs_rsync.

This function returns 0 on success or -1 on error.

(Added in 1.19.29)

guestfs_rsync_in_va

 int
 guestfs_rsync_in_va (guestfs_h *g,
                      const char *remote,
                      const char *dest,
                      va_list args);

This is the "va_list variant" of "guestfs_rsync_in".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_rsync_in_argv

 int
 guestfs_rsync_in_argv (guestfs_h *g,
                        const char *remote,
                        const char *dest,
                        const struct guestfs_rsync_in_argv *optargs);

This is the "argv variant" of "guestfs_rsync_in".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_rsync_out

 int
 guestfs_rsync_out (guestfs_h *g,
                    const char *src,
                    const char *remote,
                    ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_RSYNC_OUT_ARCHIVE, int archive,
 GUESTFS_RSYNC_OUT_DELETEDEST, int deletedest,

This call may be used to copy or synchronize the filesystem within libguestfs with a filesystem on the host or on a remote computer. This uses the rsync(1) program which uses a fast algorithm that avoids copying files unnecessarily.

This call only works if the network is enabled. See guestfs_set_network or the --network option to various tools like guestfish(1).

Files are copied from the source directory src to the remote server and directory specified by remote.

The format of the remote server string is defined by rsync(1). Note that there is no way to supply a password or passphrase so the target must be set up not to require one.

The optional arguments are the same as those of guestfs_rsync.

Globbing does not happen on the src parameter. In programs which use the API directly you have to expand wildcards yourself (see guestfs_glob_expand). In guestfish you can use the glob command (see "glob" in guestfish(1)), for example:

 ><fs> glob rsync-out /* rsync://remote/

This function returns 0 on success or -1 on error.

(Added in 1.19.29)

guestfs_rsync_out_va

 int
 guestfs_rsync_out_va (guestfs_h *g,
                       const char *src,
                       const char *remote,
                       va_list args);

This is the "va_list variant" of "guestfs_rsync_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_rsync_out_argv

 int
 guestfs_rsync_out_argv (guestfs_h *g,
                         const char *src,
                         const char *remote,
                         const struct guestfs_rsync_out_argv *optargs);

This is the "argv variant" of "guestfs_rsync_out".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_scrub_device

 int
 guestfs_scrub_device (guestfs_h *g,
                       const char *device);

This command writes patterns over device to make data retrieval more difficult.

It is an interface to the scrub(1) program. See that manual page for more details.

This function returns 0 on success or -1 on error.

(Added in 1.0.52)

guestfs_scrub_file

 int
 guestfs_scrub_file (guestfs_h *g,
                     const char *file);

This command writes patterns over a file to make data retrieval more difficult.

The file is removed after scrubbing.

It is an interface to the scrub(1) program. See that manual page for more details.

This function returns 0 on success or -1 on error.

(Added in 1.0.52)

guestfs_scrub_freespace

 int
 guestfs_scrub_freespace (guestfs_h *g,
                          const char *dir);

This command creates the directory dir and then fills it with files until the filesystem is full, and scrubs the files as for guestfs_scrub_file, and deletes them. The intention is to scrub any free space on the partition containing dir.

It is an interface to the scrub(1) program. See that manual page for more details.

This function returns 0 on success or -1 on error.

(Added in 1.0.52)

guestfs_set_append

 int
 guestfs_set_append (guestfs_h *g,
                     const char *append);

This function is used to add additional options to the guest kernel command line.

The default is NULL unless overridden by setting LIBGUESTFS_APPEND environment variable.

Setting append to NULL means no additional options are passed (libguestfs always adds a few of its own).

This function returns 0 on success or -1 on error.

(Added in 1.0.26)

guestfs_set_attach_method

 int
 guestfs_set_attach_method (guestfs_h *g,
                            const char *backend);

This function is deprecated. In new code, use the "guestfs_set_backend" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Set the method that libguestfs uses to connect to the backend guestfsd daemon.

See "BACKEND" in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.9.8)

guestfs_set_autosync

 int
 guestfs_set_autosync (guestfs_h *g,
                       int autosync);

If autosync is true, this enables autosync. Libguestfs will make a best effort attempt to make filesystems consistent and synchronized when the handle is closed (also if the program exits without closing handles).

This is enabled by default (since libguestfs 1.5.24, previously it was disabled by default).

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_set_backend

 int
 guestfs_set_backend (guestfs_h *g,
                      const char *backend);

Set the method that libguestfs uses to connect to the backend guestfsd daemon.

This handle property was previously called the "attach method".

See "BACKEND" in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.21.26)

guestfs_set_backend_setting

 int
 guestfs_set_backend_setting (guestfs_h *g,
                              const char *name,
                              const char *val);

Append "name=value" to the backend settings string list. However if a string already exists matching "name" or beginning with "name=", then that setting is replaced.

See "BACKEND" in guestfs(3), "BACKEND SETTINGS" in guestfs(3).

This function returns 0 on success or -1 on error.

guestfs_set_backend_settings

 int
 guestfs_set_backend_settings (guestfs_h *g,
                               char *const *settings);

Set a list of zero or more settings which are passed through to the current backend. Each setting is a string which is interpreted in a backend-specific way, or ignored if not understood by the backend.

The default value is an empty list, unless the environment variable LIBGUESTFS_BACKEND_SETTINGS was set when the handle was created. This environment variable contains a colon-separated list of settings.

This call replaces all backend settings. If you want to replace a single backend setting, see guestfs_set_backend_setting. If you want to clear a single backend setting, see guestfs_clear_backend_setting.

See "BACKEND" in guestfs(3), "BACKEND SETTINGS" in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.25.24)

guestfs_set_cachedir

 int
 guestfs_set_cachedir (guestfs_h *g,
                       const char *cachedir);

Set the directory used by the handle to store the appliance cache, when using a supermin appliance. The appliance is cached and shared between all handles which have the same effective user ID.

The environment variables LIBGUESTFS_CACHEDIR and TMPDIR control the default value: If LIBGUESTFS_CACHEDIR is set, then that is the default. Else if TMPDIR is set, then that is the default. Else /var/tmp is the default.

This function returns 0 on success or -1 on error.

(Added in 1.19.58)

guestfs_set_direct

 int
 guestfs_set_direct (guestfs_h *g,
                     int direct);

If the direct appliance mode flag is enabled, then stdin and stdout are passed directly through to the appliance once it is launched.

One consequence of this is that log messages aren't caught by the library and handled by guestfs_set_log_message_callback, but go straight to stdout.

You probably don't want to use this unless you know what you are doing.

The default is disabled.

This function returns 0 on success or -1 on error.

(Added in 1.0.72)

guestfs_set_e2attrs

 int
 guestfs_set_e2attrs (guestfs_h *g,
                      const char *file,
                      const char *attrs,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_SET_E2ATTRS_CLEAR, int clear,

This sets or clears the file attributes attrs associated with the inode file.

attrs is a string of characters representing file attributes. See guestfs_get_e2attrs for a list of possible attributes. Not all attributes can be changed.

If optional boolean clear is not present or false, then the attrs listed are set in the inode.

If clear is true, then the attrs listed are cleared in the inode.

In both cases, other attributes not present in the attrs string are left unchanged.

These attributes are only present when the file is located on an ext2/3/4 filesystem. Using this call on other filesystem types will result in an error.

This function returns 0 on success or -1 on error.

(Added in 1.17.31)

guestfs_set_e2attrs_va

 int
 guestfs_set_e2attrs_va (guestfs_h *g,
                         const char *file,
                         const char *attrs,
                         va_list args);

This is the "va_list variant" of "guestfs_set_e2attrs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_set_e2attrs_argv

 int
 guestfs_set_e2attrs_argv (guestfs_h *g,
                           const char *file,
                           const char *attrs,
                           const struct guestfs_set_e2attrs_argv *optargs);

This is the "argv variant" of "guestfs_set_e2attrs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_set_e2generation

 int
 guestfs_set_e2generation (guestfs_h *g,
                           const char *file,
                           int64_t generation);

This sets the ext2 file generation of a file.

See guestfs_get_e2generation.

This function returns 0 on success or -1 on error.

(Added in 1.17.31)

guestfs_set_e2label

 int
 guestfs_set_e2label (guestfs_h *g,
                      const char *device,
                      const char *label);

This function is deprecated. In new code, use the "guestfs_set_label" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This sets the ext2/3/4 filesystem label of the filesystem on device to label. Filesystem labels are limited to 16 characters.

You can use either guestfs_tune2fs_l or guestfs_get_e2label to return the existing label on a filesystem.

This function returns 0 on success or -1 on error.

(Added in 1.0.15)

guestfs_set_e2uuid

 int
 guestfs_set_e2uuid (guestfs_h *g,
                     const char *device,
                     const char *uuid);

This function is deprecated. In new code, use the "guestfs_set_uuid" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This sets the ext2/3/4 filesystem UUID of the filesystem on device to uuid. The format of the UUID and alternatives such as clear, random and time are described in the tune2fs(8) manpage.

You can use guestfs_vfs_uuid to return the existing UUID of a filesystem.

This function returns 0 on success or -1 on error.

(Added in 1.0.15)

guestfs_set_hv

 int
 guestfs_set_hv (guestfs_h *g,
                 const char *hv);

Set the hypervisor binary that we will use. The hypervisor depends on the backend, but is usually the location of the qemu/KVM hypervisor. For the uml backend, it is the location of the linux or vmlinux binary.

The default is chosen when the library was compiled by the configure script.

You can also override this by setting the LIBGUESTFS_HV environment variable.

Note that you should call this function as early as possible after creating the handle. This is because some pre-launch operations depend on testing qemu features (by running qemu -help). If the qemu binary changes, we don't retest features, and so you might see inconsistent results. Using the environment variable LIBGUESTFS_HV is safest of all since that picks the qemu binary at the same time as the handle is created.

This function returns 0 on success or -1 on error.

(Added in 1.23.17)

guestfs_set_label

 int
 guestfs_set_label (guestfs_h *g,
                    const char *mountable,
                    const char *label);

Set the filesystem label on mountable to label.

Only some filesystem types support labels, and libguestfs supports setting labels on only a subset of these.

ext2, ext3, ext4

Labels are limited to 16 bytes.

NTFS

Labels are limited to 128 unicode characters.

XFS

The label is limited to 12 bytes. The filesystem must not be mounted when trying to set the label.

btrfs

The label is limited to 256 bytes and some characters are not allowed. Setting the label on a btrfs subvolume will set the label on its parent filesystem. The filesystem must not be mounted when trying to set the label.

To read the label on a filesystem, call guestfs_vfs_label.

This function returns 0 on success or -1 on error.

(Added in 1.17.9)

guestfs_set_libvirt_requested_credential

 int
 guestfs_set_libvirt_requested_credential (guestfs_h *g,
                                           int index,
                                           const char *cred,
                                           size_t cred_size);

After requesting the index'th credential from the user, call this function to pass the answer back to libvirt.

See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.

This function returns 0 on success or -1 on error.

(Added in 1.19.52)

guestfs_set_libvirt_supported_credentials

 int
 guestfs_set_libvirt_supported_credentials (guestfs_h *g,
                                            char *const *creds);

Call this function before setting an event handler for GUESTFS_EVENT_LIBVIRT_AUTH, to supply the list of credential types that the program knows how to process.

The creds list must be a non-empty list of strings. Possible strings are:

username
authname
language
cnonce
passphrase
echoprompt
noechoprompt
realm
external

See libvirt documentation for the meaning of these credential types.

See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.

This function returns 0 on success or -1 on error.

(Added in 1.19.52)

guestfs_set_memsize

 int
 guestfs_set_memsize (guestfs_h *g,
                      int memsize);

This sets the memory size in megabytes allocated to the hypervisor. This only has any effect if called before guestfs_launch.

You can also change this by setting the environment variable LIBGUESTFS_MEMSIZE before the handle is created.

For more information on the architecture of libguestfs, see guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_set_network

 int
 guestfs_set_network (guestfs_h *g,
                      int network);

If network is true, then the network is enabled in the libguestfs appliance. The default is false.

This affects whether commands are able to access the network (see "RUNNING COMMANDS" in guestfs(3)).

You must call this before calling guestfs_launch, otherwise it has no effect.

This function returns 0 on success or -1 on error.

(Added in 1.5.4)

guestfs_set_path

 int
 guestfs_set_path (guestfs_h *g,
                   const char *searchpath);

Set the path that libguestfs searches for kernel and initrd.img.

The default is $libdir/guestfs unless overridden by setting LIBGUESTFS_PATH environment variable.

Setting path to NULL restores the default path.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_set_pgroup

 int
 guestfs_set_pgroup (guestfs_h *g,
                     int pgroup);

If pgroup is true, child processes are placed into their own process group.

The practical upshot of this is that signals like SIGINT (from users pressing ^C) won't be received by the child process.

The default for this flag is false, because usually you want ^C to kill the subprocess. Guestfish sets this flag to true when used interactively, so that ^C can cancel long-running commands gracefully (see guestfs_user_cancel).

This function returns 0 on success or -1 on error.

(Added in 1.11.18)

guestfs_set_program

 int
 guestfs_set_program (guestfs_h *g,
                      const char *program);

Set the program name. This is an informative string which the main program may optionally set in the handle.

When the handle is created, the program name in the handle is set to the basename from argv[0]. If that was not possible, it is set to the empty string (but never NULL).

This function returns 0 on success or -1 on error.

(Added in 1.21.29)

guestfs_set_qemu

 int
 guestfs_set_qemu (guestfs_h *g,
                   const char *hv);

This function is deprecated. In new code, use the "guestfs_set_hv" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

Set the hypervisor binary (usually qemu) that we will use.

The default is chosen when the library was compiled by the configure script.

You can also override this by setting the LIBGUESTFS_HV environment variable.

Setting hv to NULL restores the default qemu binary.

Note that you should call this function as early as possible after creating the handle. This is because some pre-launch operations depend on testing qemu features (by running qemu -help). If the qemu binary changes, we don't retest features, and so you might see inconsistent results. Using the environment variable LIBGUESTFS_HV is safest of all since that picks the qemu binary at the same time as the handle is created.

This function returns 0 on success or -1 on error.

(Added in 1.0.6)

guestfs_set_recovery_proc

 int
 guestfs_set_recovery_proc (guestfs_h *g,
                            int recoveryproc);

If this is called with the parameter false then guestfs_launch does not create a recovery process. The purpose of the recovery process is to stop runaway hypervisor processes in the case where the main program aborts abruptly.

This only has any effect if called before guestfs_launch, and the default is true.

About the only time when you would want to disable this is if the main process will fork itself into the background ("daemonize" itself). In this case the recovery process thinks that the main program has disappeared and so kills the hypervisor, which is not very helpful.

This function returns 0 on success or -1 on error.

(Added in 1.0.77)

guestfs_set_selinux

 int
 guestfs_set_selinux (guestfs_h *g,
                      int selinux);

This sets the selinux flag that is passed to the appliance at boot time. The default is selinux=0 (disabled).

Note that if SELinux is enabled, it is always in Permissive mode (enforcing=0).

For more information on the architecture of libguestfs, see guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.0.67)

guestfs_set_smp

 int
 guestfs_set_smp (guestfs_h *g,
                  int smp);

Change the number of virtual CPUs assigned to the appliance. The default is 1. Increasing this may improve performance, though often it has no effect.

This function must be called before guestfs_launch.

This function returns 0 on success or -1 on error.

(Added in 1.13.15)

guestfs_set_tmpdir

 int
 guestfs_set_tmpdir (guestfs_h *g,
                     const char *tmpdir);

Set the directory used by the handle to store temporary files.

The environment variables LIBGUESTFS_TMPDIR and TMPDIR control the default value: If LIBGUESTFS_TMPDIR is set, then that is the default. Else if TMPDIR is set, then that is the default. Else /tmp is the default.

This function returns 0 on success or -1 on error.

(Added in 1.19.58)

guestfs_set_trace

 int
 guestfs_set_trace (guestfs_h *g,
                    int trace);

If the command trace flag is set to 1, then libguestfs calls, parameters and return values are traced.

If you want to trace C API calls into libguestfs (and other libraries) then possibly a better way is to use the external ltrace(1) command.

Command traces are disabled unless the environment variable LIBGUESTFS_TRACE is defined and set to 1.

Trace messages are normally sent to stderr, unless you register a callback to send them somewhere else (see guestfs_set_event_callback).

This function returns 0 on success or -1 on error.

(Added in 1.0.69)

guestfs_set_uuid

 int
 guestfs_set_uuid (guestfs_h *g,
                   const char *device,
                   const char *uuid);

Set the filesystem UUID on device to uuid.

Only some filesystem types support setting UUIDs.

To read the UUID on a filesystem, call guestfs_vfs_uuid.

This function returns 0 on success or -1 on error.

(Added in 1.23.10)

guestfs_set_verbose

 int
 guestfs_set_verbose (guestfs_h *g,
                      int verbose);

If verbose is true, this turns on verbose messages.

Verbose messages are disabled unless the environment variable LIBGUESTFS_DEBUG is defined and set to 1.

Verbose messages are normally sent to stderr, unless you register a callback to send them somewhere else (see guestfs_set_event_callback).

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_setcon

 int
 guestfs_setcon (guestfs_h *g,
                 const char *context);

This sets the SELinux security context of the daemon to the string context.

See the documentation about SELINUX in guestfs(3).

This function returns 0 on success or -1 on error.

(Added in 1.0.67)

guestfs_setxattr

 int
 guestfs_setxattr (guestfs_h *g,
                   const char *xattr,
                   const char *val,
                   int vallen,
                   const char *path);

This call sets the extended attribute named xattr of the file path to the value val (of length vallen). The value is arbitrary 8 bit data.

See also: guestfs_lsetxattr, attr(5).

This function returns 0 on success or -1 on error.

(Added in 1.0.59)

guestfs_sfdisk

 int
 guestfs_sfdisk (guestfs_h *g,
                 const char *device,
                 int cyls,
                 int heads,
                 int sectors,
                 char *const *lines);

This function is deprecated. In new code, use the "guestfs_part_add" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This is a direct interface to the sfdisk(8) program for creating partitions on block devices.

device should be a block device, for example /dev/sda.

cyls, heads and sectors are the number of cylinders, heads and sectors on the device, which are passed directly to sfdisk as the -C, -H and -S parameters. If you pass 0 for any of these, then the corresponding parameter is omitted. Usually for 'large' disks, you can just pass 0 for these, but for small (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work out the right geometry and you will need to tell it.

lines is a list of lines that we feed to sfdisk. For more information refer to the sfdisk(8) manpage.

To create a single partition occupying the whole disk, you would pass lines as a single element list, when the single element being the string , (comma).

See also: guestfs_sfdisk_l, guestfs_sfdisk_N, guestfs_part_init

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_sfdiskM

 int
 guestfs_sfdiskM (guestfs_h *g,
                  const char *device,
                  char *const *lines);

This function is deprecated. In new code, use the "guestfs_part_add" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This is a simplified interface to the guestfs_sfdisk command, where partition sizes are specified in megabytes only (rounded to the nearest cylinder) and you don't need to specify the cyls, heads and sectors parameters which were rarely if ever used anyway.

See also: guestfs_sfdisk, the sfdisk(8) manpage and guestfs_part_disk

This function returns 0 on success or -1 on error.

(Added in 1.0.55)

guestfs_sfdisk_N

 int
 guestfs_sfdisk_N (guestfs_h *g,
                   const char *device,
                   int partnum,
                   int cyls,
                   int heads,
                   int sectors,
                   const char *line);

This function is deprecated. In new code, use the "guestfs_part_add" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This runs sfdisk(8) option to modify just the single partition n (note: n counts from 1).

For other parameters, see guestfs_sfdisk. You should usually pass 0 for the cyls/heads/sectors parameters.

See also: guestfs_part_add

This function returns 0 on success or -1 on error.

(Added in 1.0.26)

guestfs_sfdisk_disk_geometry

 char *
 guestfs_sfdisk_disk_geometry (guestfs_h *g,
                               const char *device);

This displays the disk geometry of device read from the partition table. Especially in the case where the underlying block device has been resized, this can be different from the kernel's idea of the geometry (see guestfs_sfdisk_kernel_geometry).

The result is in human-readable format, and not designed to be parsed.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.26)

guestfs_sfdisk_kernel_geometry

 char *
 guestfs_sfdisk_kernel_geometry (guestfs_h *g,
                                 const char *device);

This displays the kernel's idea of the geometry of device.

The result is in human-readable format, and not designed to be parsed.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.26)

guestfs_sfdisk_l

 char *
 guestfs_sfdisk_l (guestfs_h *g,
                   const char *device);

This function is deprecated. In new code, use the "guestfs_part_list" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This displays the partition table on device, in the human-readable output of the sfdisk(8) command. It is not intended to be parsed.

See also: guestfs_part_list

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.26)

guestfs_sh

 char *
 guestfs_sh (guestfs_h *g,
             const char *command);

This call runs a command from the guest filesystem via the guest's /bin/sh.

This is like guestfs_command, but passes the command to:

 /bin/sh -c "command"

Depending on the guest's shell, this usually results in wildcards being expanded, shell expressions being interpolated and so on.

All the provisos about guestfs_command apply to this call.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.50)

guestfs_sh_lines

 char **
 guestfs_sh_lines (guestfs_h *g,
                   const char *command);

This is the same as guestfs_sh, but splits the result into a list of lines.

See also: guestfs_command_lines

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.50)

guestfs_shutdown

 int
 guestfs_shutdown (guestfs_h *g);

This is the opposite of guestfs_launch. It performs an orderly shutdown of the backend process(es). If the autosync flag is set (which is the default) then the disk image is synchronized.

If the subprocess exits with an error then this function will return an error, which should not be ignored (it may indicate that the disk image could not be written out properly).

It is safe to call this multiple times. Extra calls are ignored.

This call does not close or free up the handle. You still need to call guestfs_close afterwards.

guestfs_close will call this if you don't do it explicitly, but note that any errors are ignored in that case.

This function returns 0 on success or -1 on error.

(Added in 1.19.16)

guestfs_sleep

 int
 guestfs_sleep (guestfs_h *g,
                int secs);

Sleep for secs seconds.

This function returns 0 on success or -1 on error.

(Added in 1.0.41)

guestfs_stat

 struct guestfs_stat *
 guestfs_stat (guestfs_h *g,
               const char *path);

Returns file information for the given path.

This is the same as the stat(2) system call.

This function returns a struct guestfs_stat *, or NULL if there was an error. The caller must call guestfs_free_stat after use.

(Added in 0.9.2)

guestfs_statvfs

 struct guestfs_statvfs *
 guestfs_statvfs (guestfs_h *g,
                  const char *path);

Returns file system statistics for any mounted file system. path should be a file or directory in the mounted file system (typically it is the mount point itself, but it doesn't need to be).

This is the same as the statvfs(2) system call.

This function returns a struct guestfs_statvfs *, or NULL if there was an error. The caller must call guestfs_free_statvfs after use.

(Added in 0.9.2)

guestfs_strings

 char **
 guestfs_strings (guestfs_h *g,
                  const char *path);

This runs the strings(1) command on a file and returns the list of printable strings found.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.22)

guestfs_strings_e

 char **
 guestfs_strings_e (guestfs_h *g,
                    const char *encoding,
                    const char *path);

This is like the guestfs_strings command, but allows you to specify the encoding of strings that are looked for in the source file path.

Allowed encodings are:

s

Single 7-bit-byte characters like ASCII and the ASCII-compatible parts of ISO-8859-X (this is what guestfs_strings uses).

S

Single 8-bit-byte characters.

b

16-bit big endian strings such as those encoded in UTF-16BE or UCS-2BE.

l (lower case letter L)

16-bit little endian such as UTF-16LE and UCS-2LE. This is useful for examining binaries in Windows guests.

B

32-bit big endian such as UCS-4BE.

L

32-bit little endian such as UCS-4LE.

The returned strings are transcoded to UTF-8.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.22)

guestfs_swapoff_device

 int
 guestfs_swapoff_device (guestfs_h *g,
                         const char *device);

This command disables the libguestfs appliance swap device or partition named device. See guestfs_swapon_device.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapoff_file

 int
 guestfs_swapoff_file (guestfs_h *g,
                       const char *file);

This command disables the libguestfs appliance swap on file.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapoff_label

 int
 guestfs_swapoff_label (guestfs_h *g,
                        const char *label);

This command disables the libguestfs appliance swap on labeled swap partition.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapoff_uuid

 int
 guestfs_swapoff_uuid (guestfs_h *g,
                       const char *uuid);

This command disables the libguestfs appliance swap partition with the given UUID.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapon_device

 int
 guestfs_swapon_device (guestfs_h *g,
                        const char *device);

This command enables the libguestfs appliance to use the swap device or partition named device. The increased memory is made available for all commands, for example those run using guestfs_command or guestfs_sh.

Note that you should not swap to existing guest swap partitions unless you know what you are doing. They may contain hibernation information, or other information that the guest doesn't want you to trash. You also risk leaking information about the host to the guest this way. Instead, attach a new host device to the guest and swap on that.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapon_file

 int
 guestfs_swapon_file (guestfs_h *g,
                      const char *file);

This command enables swap to a file. See guestfs_swapon_device for other notes.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapon_label

 int
 guestfs_swapon_label (guestfs_h *g,
                       const char *label);

This command enables swap to a labeled swap partition. See guestfs_swapon_device for other notes.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_swapon_uuid

 int
 guestfs_swapon_uuid (guestfs_h *g,
                      const char *uuid);

This command enables swap to a swap partition with the given UUID. See guestfs_swapon_device for other notes.

This function returns 0 on success or -1 on error.

(Added in 1.0.66)

guestfs_sync

 int
 guestfs_sync (guestfs_h *g);

This syncs the disk, so that any writes are flushed through to the underlying disk image.

You should always call this if you have modified a disk image, before closing the handle.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_syslinux

 int
 guestfs_syslinux (guestfs_h *g,
                   const char *device,
                   ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_SYSLINUX_DIRECTORY, const char *directory,

Install the SYSLINUX bootloader on device.

The device parameter must be either a whole disk formatted as a FAT filesystem, or a partition formatted as a FAT filesystem. In the latter case, the partition should be marked as "active" (guestfs_part_set_bootable) and a Master Boot Record must be installed (eg. using guestfs_pwrite_device) on the first sector of the whole disk. The SYSLINUX package comes with some suitable Master Boot Records. See the syslinux(1) man page for further information.

The optional arguments are:

directory

Install SYSLINUX in the named subdirectory, instead of in the root directory of the FAT filesystem.

Additional configuration can be supplied to SYSLINUX by placing a file called syslinux.cfg on the FAT filesystem, either in the root directory, or under directory if that optional argument is being used. For further information about the contents of this file, see syslinux(1).

See also guestfs_extlinux.

This function returns 0 on success or -1 on error.

(Added in 1.21.27)

guestfs_syslinux_va

 int
 guestfs_syslinux_va (guestfs_h *g,
                      const char *device,
                      va_list args);

This is the "va_list variant" of "guestfs_syslinux".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_syslinux_argv

 int
 guestfs_syslinux_argv (guestfs_h *g,
                        const char *device,
                        const struct guestfs_syslinux_argv *optargs);

This is the "argv variant" of "guestfs_syslinux".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tail

 char **
 guestfs_tail (guestfs_h *g,
               const char *path);

This command returns up to the last 10 lines of a file as a list of strings.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.54)

guestfs_tail_n

 char **
 guestfs_tail_n (guestfs_h *g,
                 int nrlines,
                 const char *path);

If the parameter nrlines is a positive number, this returns the last nrlines lines of the file path.

If the parameter nrlines is a negative number, this returns lines from the file path, starting with the -nrlinesth line.

If the parameter nrlines is zero, this returns an empty list.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.54)

guestfs_tar_in

 int
 guestfs_tar_in (guestfs_h *g,
                 const char *tarfile,
                 const char *directory);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_tar_in_opts" with no optional arguments.

(Added in 1.0.3)

guestfs_tar_in_opts

 int
 guestfs_tar_in_opts (guestfs_h *g,
                      const char *tarfile,
                      const char *directory,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_TAR_IN_OPTS_COMPRESS, const char *compress,

This command uploads and unpacks local file tarfile into directory.

The optional compress flag controls compression. If not given, then the input should be an uncompressed tar file. Otherwise one of the following strings may be given to select the compression type of the input file: compress, gzip, bzip2, xz, lzop. (Note that not all builds of libguestfs will support all of these compression types).

This function returns 0 on success or -1 on error.

(Added in 1.19.30)

guestfs_tar_in_opts_va

 int
 guestfs_tar_in_opts_va (guestfs_h *g,
                         const char *tarfile,
                         const char *directory,
                         va_list args);

This is the "va_list variant" of "guestfs_tar_in_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tar_in_opts_argv

 int
 guestfs_tar_in_opts_argv (guestfs_h *g,
                           const char *tarfile,
                           const char *directory,
                           const struct guestfs_tar_in_opts_argv *optargs);

This is the "argv variant" of "guestfs_tar_in_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tar_out

 int
 guestfs_tar_out (guestfs_h *g,
                  const char *directory,
                  const char *tarfile);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_tar_out_opts" with no optional arguments.

(Added in 1.0.3)

guestfs_tar_out_opts

 int
 guestfs_tar_out_opts (guestfs_h *g,
                       const char *directory,
                       const char *tarfile,
                       ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_TAR_OUT_OPTS_COMPRESS, const char *compress,
 GUESTFS_TAR_OUT_OPTS_NUMERICOWNER, int numericowner,
 GUESTFS_TAR_OUT_OPTS_EXCLUDES, char *const *excludes,

This command packs the contents of directory and downloads it to local file tarfile.

The optional compress flag controls compression. If not given, then the output will be an uncompressed tar file. Otherwise one of the following strings may be given to select the compression type of the output file: compress, gzip, bzip2, xz, lzop. (Note that not all builds of libguestfs will support all of these compression types).

The other optional arguments are:

excludes

A list of wildcards. Files are excluded if they match any of the wildcards.

numericowner

If set to true, the output tar file will contain UID/GID numbers instead of user/group names.

This function returns 0 on success or -1 on error.

(Added in 1.19.30)

guestfs_tar_out_opts_va

 int
 guestfs_tar_out_opts_va (guestfs_h *g,
                          const char *directory,
                          const char *tarfile,
                          va_list args);

This is the "va_list variant" of "guestfs_tar_out_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tar_out_opts_argv

 int
 guestfs_tar_out_opts_argv (guestfs_h *g,
                            const char *directory,
                            const char *tarfile,
                            const struct guestfs_tar_out_opts_argv *optargs);

This is the "argv variant" of "guestfs_tar_out_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tgz_in

 int
 guestfs_tgz_in (guestfs_h *g,
                 const char *tarball,
                 const char *directory);

This function is deprecated. In new code, use the "guestfs_tar_in" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command uploads and unpacks local file tarball (a gzip compressed tar file) into directory.

This function returns 0 on success or -1 on error.

(Added in 1.0.3)

guestfs_tgz_out

 int
 guestfs_tgz_out (guestfs_h *g,
                  const char *directory,
                  const char *tarball);

This function is deprecated. In new code, use the "guestfs_tar_out" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command packs the contents of directory and downloads it to local file tarball.

This function returns 0 on success or -1 on error.

(Added in 1.0.3)

guestfs_touch

 int
 guestfs_touch (guestfs_h *g,
                const char *path);

Touch acts like the touch(1) command. It can be used to update the timestamps on a file, or, if the file does not exist, to create a new zero-length file.

This command only works on regular files, and will fail on other file types such as directories, symbolic links, block special etc.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_truncate

 int
 guestfs_truncate (guestfs_h *g,
                   const char *path);

This command truncates path to a zero-length file. The file must exist already.

This function returns 0 on success or -1 on error.

(Added in 1.0.77)

guestfs_truncate_size

 int
 guestfs_truncate_size (guestfs_h *g,
                        const char *path,
                        int64_t size);

This command truncates path to size size bytes. The file must exist already.

If the current file size is less than size then the file is extended to the required size with zero bytes. This creates a sparse file (ie. disk blocks are not allocated for the file until you write to it). To create a non-sparse file of zeroes, use guestfs_fallocate64 instead.

This function returns 0 on success or -1 on error.

(Added in 1.0.77)

guestfs_tune2fs

 int
 guestfs_tune2fs (guestfs_h *g,
                  const char *device,
                  ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_TUNE2FS_FORCE, int force,
 GUESTFS_TUNE2FS_MAXMOUNTCOUNT, int maxmountcount,
 GUESTFS_TUNE2FS_MOUNTCOUNT, int mountcount,
 GUESTFS_TUNE2FS_ERRORBEHAVIOR, const char *errorbehavior,
 GUESTFS_TUNE2FS_GROUP, int64_t group,
 GUESTFS_TUNE2FS_INTERVALBETWEENCHECKS, int intervalbetweenchecks,
 GUESTFS_TUNE2FS_RESERVEDBLOCKSPERCENTAGE, int reservedblockspercentage,
 GUESTFS_TUNE2FS_LASTMOUNTEDDIRECTORY, const char *lastmounteddirectory,
 GUESTFS_TUNE2FS_RESERVEDBLOCKSCOUNT, int64_t reservedblockscount,
 GUESTFS_TUNE2FS_USER, int64_t user,

This call allows you to adjust various filesystem parameters of an ext2/ext3/ext4 filesystem called device.

The optional parameters are:

force

Force tune2fs to complete the operation even in the face of errors. This is the same as the tune2fs -f option.

maxmountcount

Set the number of mounts after which the filesystem is checked by e2fsck(8). If this is 0 then the number of mounts is disregarded. This is the same as the tune2fs -c option.

mountcount

Set the number of times the filesystem has been mounted. This is the same as the tune2fs -C option.

errorbehavior

Change the behavior of the kernel code when errors are detected. Possible values currently are: continue, remount-ro, panic. In practice these options don't really make any difference, particularly for write errors.

This is the same as the tune2fs -e option.

group

Set the group which can use reserved filesystem blocks. This is the same as the tune2fs -g option except that it can only be specified as a number.

intervalbetweenchecks

Adjust the maximal time between two filesystem checks (in seconds). If the option is passed as 0 then time-dependent checking is disabled.

This is the same as the tune2fs -i option.

reservedblockspercentage

Set the percentage of the filesystem which may only be allocated by privileged processes. This is the same as the tune2fs -m option.

lastmounteddirectory

Set the last mounted directory. This is the same as the tune2fs -M option.

reservedblockscount Set the number of reserved filesystem blocks. This is the same as the tune2fs -r option.
user

Set the user who can use the reserved filesystem blocks. This is the same as the tune2fs -u option except that it can only be specified as a number.

To get the current values of filesystem parameters, see guestfs_tune2fs_l. For precise details of how tune2fs works, see the tune2fs(8) man page.

This function returns 0 on success or -1 on error.

(Added in 1.15.4)

guestfs_tune2fs_va

 int
 guestfs_tune2fs_va (guestfs_h *g,
                     const char *device,
                     va_list args);

This is the "va_list variant" of "guestfs_tune2fs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tune2fs_argv

 int
 guestfs_tune2fs_argv (guestfs_h *g,
                       const char *device,
                       const struct guestfs_tune2fs_argv *optargs);

This is the "argv variant" of "guestfs_tune2fs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_tune2fs_l

 char **
 guestfs_tune2fs_l (guestfs_h *g,
                    const char *device);

This returns the contents of the ext2, ext3 or ext4 filesystem superblock on device.

It is the same as running tune2fs -l device. See tune2fs(8) manpage for more details. The list of fields returned isn't clearly defined, and depends on both the version of tune2fs that libguestfs was built against, and the filesystem itself.

This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length 2n+1, where n keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use.

(Added in 0.9.2)

guestfs_txz_in

 int
 guestfs_txz_in (guestfs_h *g,
                 const char *tarball,
                 const char *directory);

This function is deprecated. In new code, use the "guestfs_tar_in" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command uploads and unpacks local file tarball (an xz compressed tar file) into directory.

This function returns 0 on success or -1 on error.

(Added in 1.3.2)

guestfs_txz_out

 int
 guestfs_txz_out (guestfs_h *g,
                  const char *directory,
                  const char *tarball);

This function is deprecated. In new code, use the "guestfs_tar_out" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command packs the contents of directory and downloads it to local file tarball (as an xz compressed tar archive).

This function returns 0 on success or -1 on error.

(Added in 1.3.2)

guestfs_umask

 int
 guestfs_umask (guestfs_h *g,
                int mask);

This function sets the mask used for creating new files and device nodes to mask & 0777.

Typical umask values would be 022 which creates new files with permissions like "-rw-r--r--" or "-rwxr-xr-x", and 002 which creates new files with permissions like "-rw-rw-r--" or "-rwxrwxr-x".

The default umask is 022. This is important because it means that directories and device nodes will be created with 0644 or 0755 mode even if you specify 0777.

See also guestfs_get_umask, umask(2), guestfs_mknod, guestfs_mkdir.

This call returns the previous umask.

On error this function returns -1.

(Added in 1.0.55)

guestfs_umount

 int
 guestfs_umount (guestfs_h *g,
                 const char *pathordevice);

This function is provided for backwards compatibility with earlier versions of libguestfs. It simply calls "guestfs_umount_opts" with no optional arguments.

(Added in 0.8)

guestfs_umount_opts

 int
 guestfs_umount_opts (guestfs_h *g,
                      const char *pathordevice,
                      ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_UMOUNT_OPTS_FORCE, int force,
 GUESTFS_UMOUNT_OPTS_LAZYUNMOUNT, int lazyunmount,

This unmounts the given filesystem. The filesystem may be specified either by its mountpoint (path) or the device which contains the filesystem.

This function returns 0 on success or -1 on error.

(Added in 1.19.25)

guestfs_umount_opts_va

 int
 guestfs_umount_opts_va (guestfs_h *g,
                         const char *pathordevice,
                         va_list args);

This is the "va_list variant" of "guestfs_umount_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_umount_opts_argv

 int
 guestfs_umount_opts_argv (guestfs_h *g,
                           const char *pathordevice,
                           const struct guestfs_umount_opts_argv *optargs);

This is the "argv variant" of "guestfs_umount_opts".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_umount_all

 int
 guestfs_umount_all (guestfs_h *g);

This unmounts all mounted filesystems.

Some internal mounts are not unmounted by this call.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_umount_local

 int
 guestfs_umount_local (guestfs_h *g,
                       ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_UMOUNT_LOCAL_RETRY, int retry,

If libguestfs is exporting the filesystem on a local mountpoint, then this unmounts it.

See "MOUNT LOCAL" in guestfs(3) for full documentation.

This function returns 0 on success or -1 on error.

(Added in 1.17.22)

guestfs_umount_local_va

 int
 guestfs_umount_local_va (guestfs_h *g,
                          va_list args);

This is the "va_list variant" of "guestfs_umount_local".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_umount_local_argv

 int
 guestfs_umount_local_argv (guestfs_h *g,
                            const struct guestfs_umount_local_argv *optargs);

This is the "argv variant" of "guestfs_umount_local".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_upload

 int
 guestfs_upload (guestfs_h *g,
                 const char *filename,
                 const char *remotefilename);

Upload local file filename to remotefilename on the filesystem.

filename can also be a named pipe.

See also guestfs_download.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.0.2)

guestfs_upload_offset

 int
 guestfs_upload_offset (guestfs_h *g,
                        const char *filename,
                        const char *remotefilename,
                        int64_t offset);

Upload local file filename to remotefilename on the filesystem.

remotefilename is overwritten starting at the byte offset specified. The intention is to overwrite parts of existing files or devices, although if a non-existant file is specified then it is created with a "hole" before offset. The size of the data written is implicit in the size of the source filename.

Note that there is no limit on the amount of data that can be uploaded with this call, unlike with guestfs_pwrite, and this call always writes the full amount unless an error occurs.

See also guestfs_upload, guestfs_pwrite.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.5.17)

guestfs_user_cancel

 int
 guestfs_user_cancel (guestfs_h *g);

This function cancels the current upload or download operation.

Unlike most other libguestfs calls, this function is signal safe and thread safe. You can call it from a signal handler or from another thread, without needing to do any locking.

The transfer that was in progress (if there is one) will stop shortly afterwards, and will return an error. The errno (see "guestfs_last_errno") is set to EINTR, so you can test for this to find out if the operation was cancelled or failed because of another error.

No cleanup is performed: for example, if a file was being uploaded then after cancellation there may be a partially uploaded file. It is the caller's responsibility to clean up if necessary.

There are two common places that you might call guestfs_user_cancel:

In an interactive text-based program, you might call it from a SIGINT signal handler so that pressing ^C cancels the current operation. (You also need to call "guestfs_set_pgroup" so that child processes don't receive the ^C signal).

In a graphical program, when the main thread is displaying a progress bar with a cancel button, wire up the cancel button to call this function.

This function returns 0 on success or -1 on error.

(Added in 1.11.18)

guestfs_utimens

 int
 guestfs_utimens (guestfs_h *g,
                  const char *path,
                  int64_t atsecs,
                  int64_t atnsecs,
                  int64_t mtsecs,
                  int64_t mtnsecs);

This command sets the timestamps of a file with nanosecond precision.

atsecs, atnsecs are the last access time (atime) in secs and nanoseconds from the epoch.

mtsecs, mtnsecs are the last modification time (mtime) in secs and nanoseconds from the epoch.

If the *nsecs field contains the special value -1 then the corresponding timestamp is set to the current time. (The *secs field is ignored in this case).

If the *nsecs field contains the special value -2 then the corresponding timestamp is left unchanged. (The *secs field is ignored in this case).

This function returns 0 on success or -1 on error.

(Added in 1.0.77)

guestfs_utsname

 struct guestfs_utsname *
 guestfs_utsname (guestfs_h *g);

This returns the kernel version of the appliance, where this is available. This information is only useful for debugging. Nothing in the returned structure is defined by the API.

This function returns a struct guestfs_utsname *, or NULL if there was an error. The caller must call guestfs_free_utsname after use.

(Added in 1.19.27)

guestfs_version

 struct guestfs_version *
 guestfs_version (guestfs_h *g);

Return the libguestfs version number that the program is linked against.

Note that because of dynamic linking this is not necessarily the version of libguestfs that you compiled against. You can compile the program, and then at runtime dynamically link against a completely different libguestfs.so library.

This call was added in version 1.0.58. In previous versions of libguestfs there was no way to get the version number. From C code you can use dynamic linker functions to find out if this symbol exists (if it doesn't, then it's an earlier version).

The call returns a structure with four elements. The first three (major, minor and release) are numbers and correspond to the usual version triplet. The fourth element (extra) is a string and is normally empty, but may be used for distro-specific information.

To construct the original version string: $major.$minor.$release$extra

See also: "LIBGUESTFS VERSION NUMBERS" in guestfs(3).

Note: Don't use this call to test for availability of features. In enterprise distributions we backport features from later versions into earlier versions, making this an unreliable way to test for features. Use guestfs_available or guestfs_feature_available instead.

This function returns a struct guestfs_version *, or NULL if there was an error. The caller must call guestfs_free_version after use.

(Added in 1.0.58)

guestfs_vfs_label

 char *
 guestfs_vfs_label (guestfs_h *g,
                    const char *mountable);

This returns the label of the filesystem on mountable.

If the filesystem is unlabeled, this returns the empty string.

To find a filesystem from the label, use guestfs_findfs_label.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.3.18)

guestfs_vfs_type

 char *
 guestfs_vfs_type (guestfs_h *g,
                   const char *mountable);

This command gets the filesystem type corresponding to the filesystem on mountable.

For most filesystems, the result is the name of the Linux VFS module which would be used to mount this filesystem if you mounted it without specifying the filesystem type. For example a string such as ext3 or ntfs.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.75)

guestfs_vfs_uuid

 char *
 guestfs_vfs_uuid (guestfs_h *g,
                   const char *mountable);

This returns the filesystem UUID of the filesystem on mountable.

If the filesystem does not have a UUID, this returns the empty string.

To find a filesystem from the UUID, use guestfs_findfs_uuid.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.3.18)

guestfs_vg_activate

 int
 guestfs_vg_activate (guestfs_h *g,
                      int activate,
                      char *const *volgroups);

This command activates or (if activate is false) deactivates all logical volumes in the listed volume groups volgroups.

This command is the same as running vgchange -a y|n volgroups...

Note that if volgroups is an empty list then all volume groups are activated or deactivated.

This function returns 0 on success or -1 on error.

(Added in 1.0.26)

guestfs_vg_activate_all

 int
 guestfs_vg_activate_all (guestfs_h *g,
                          int activate);

This command activates or (if activate is false) deactivates all logical volumes in all volume groups.

This command is the same as running vgchange -a y|n

This function returns 0 on success or -1 on error.

(Added in 1.0.26)

guestfs_vgchange_uuid

 int
 guestfs_vgchange_uuid (guestfs_h *g,
                        const char *vg);

Generate a new random UUID for the volume group vg.

This function returns 0 on success or -1 on error.

(Added in 1.19.26)

guestfs_vgchange_uuid_all

 int
 guestfs_vgchange_uuid_all (guestfs_h *g);

Generate new random UUIDs for all volume groups.

This function returns 0 on success or -1 on error.

(Added in 1.19.26)

guestfs_vgcreate

 int
 guestfs_vgcreate (guestfs_h *g,
                   const char *volgroup,
                   char *const *physvols);

This creates an LVM volume group called volgroup from the non-empty list of physical volumes physvols.

This function returns 0 on success or -1 on error.

(Added in 0.8)

guestfs_vglvuuids

 char **
 guestfs_vglvuuids (guestfs_h *g,
                    const char *vgname);

Given a VG called vgname, this returns the UUIDs of all the logical volumes created in this volume group.

You can use this along with guestfs_lvs and guestfs_lvuuid calls to associate logical volumes and volume groups.

See also guestfs_vgpvuuids.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.87)

guestfs_vgmeta

 char *
 guestfs_vgmeta (guestfs_h *g,
                 const char *vgname,
                 size_t *size_r);

vgname is an LVM volume group. This command examines the volume group and returns its metadata.

Note that the metadata is an internal structure used by LVM, subject to change at any time, and is provided for information only.

This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use.

(Added in 1.17.20)

guestfs_vgpvuuids

 char **
 guestfs_vgpvuuids (guestfs_h *g,
                    const char *vgname);

Given a VG called vgname, this returns the UUIDs of all the physical volumes that this volume group resides on.

You can use this along with guestfs_pvs and guestfs_pvuuid calls to associate physical volumes and volume groups.

See also guestfs_vglvuuids.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 1.0.87)

guestfs_vgremove

 int
 guestfs_vgremove (guestfs_h *g,
                   const char *vgname);

Remove an LVM volume group vgname, (for example VG).

This also forcibly removes all logical volumes in the volume group (if any).

This function returns 0 on success or -1 on error.

(Added in 1.0.13)

guestfs_vgrename

 int
 guestfs_vgrename (guestfs_h *g,
                   const char *volgroup,
                   const char *newvolgroup);

Rename a volume group volgroup with the new name newvolgroup.

This function returns 0 on success or -1 on error.

(Added in 1.0.83)

guestfs_vgs

 char **
 guestfs_vgs (guestfs_h *g);

List all the volumes groups detected. This is the equivalent of the vgs(8) command.

This returns a list of just the volume group names that were detected (eg. VolGroup00).

See also guestfs_vgs_full.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

(Added in 0.4)

guestfs_vgs_full

 struct guestfs_lvm_vg_list *
 guestfs_vgs_full (guestfs_h *g);

List all the volumes groups detected. This is the equivalent of the vgs(8) command. The "full" version includes all fields.

This function returns a struct guestfs_lvm_vg_list *, or NULL if there was an error. The caller must call guestfs_free_lvm_vg_list after use.

(Added in 0.4)

guestfs_vgscan

 int
 guestfs_vgscan (guestfs_h *g);

This rescans all block devices and rebuilds the list of LVM physical volumes, volume groups and logical volumes.

This function returns 0 on success or -1 on error.

(Added in 1.3.2)

guestfs_vguuid

 char *
 guestfs_vguuid (guestfs_h *g,
                 const char *vgname);

This command returns the UUID of the LVM VG named vgname.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.87)

guestfs_wait_ready

 int
 guestfs_wait_ready (guestfs_h *g);

This function is deprecated. In new code, use the "guestfs_launch" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This function is a no op.

In versions of the API < 1.0.71 you had to call this function just after calling guestfs_launch to wait for the launch to complete. However this is no longer necessary because guestfs_launch now does the waiting.

If you see any calls to this function in code then you can just remove them, unless you want to retain compatibility with older versions of the API.

This function returns 0 on success or -1 on error.

(Added in 0.3)

guestfs_wc_c

 int
 guestfs_wc_c (guestfs_h *g,
               const char *path);

This command counts the characters in a file, using the wc -c external command.

On error this function returns -1.

(Added in 1.0.54)

guestfs_wc_l

 int
 guestfs_wc_l (guestfs_h *g,
               const char *path);

This command counts the lines in a file, using the wc -l external command.

On error this function returns -1.

(Added in 1.0.54)

guestfs_wc_w

 int
 guestfs_wc_w (guestfs_h *g,
               const char *path);

This command counts the words in a file, using the wc -w external command.

On error this function returns -1.

(Added in 1.0.54)

guestfs_wipefs

 int
 guestfs_wipefs (guestfs_h *g,
                 const char *device);

This command erases filesystem or RAID signatures from the specified device to make the filesystem invisible to libblkid.

This does not erase the filesystem itself nor any other data from the device.

Compare with guestfs_zero which zeroes the first few blocks of a device.

This function returns 0 on success or -1 on error.

(Added in 1.17.6)

guestfs_write

 int
 guestfs_write (guestfs_h *g,
                const char *path,
                const char *content,
                size_t content_size);

This call creates a file called path. The content of the file is the string content (which can contain any 8 bit data).

See also guestfs_write_append.

This function returns 0 on success or -1 on error.

(Added in 1.3.14)

guestfs_write_append

 int
 guestfs_write_append (guestfs_h *g,
                       const char *path,
                       const char *content,
                       size_t content_size);

This call appends content to the end of file path. If path does not exist, then a new file is created.

See also guestfs_write.

This function returns 0 on success or -1 on error.

(Added in 1.11.18)

guestfs_write_file

 int
 guestfs_write_file (guestfs_h *g,
                     const char *path,
                     const char *content,
                     int size);

This function is deprecated. In new code, use the "guestfs_write" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This call creates a file called path. The contents of the file is the string content (which can contain any 8 bit data), with length size.

As a special case, if size is 0 then the length is calculated using strlen (so in this case the content cannot contain embedded ASCII NULs).

NB. Owing to a bug, writing content containing ASCII NUL characters does not work, even if the length is specified.

This function returns 0 on success or -1 on error.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 0.8)

guestfs_xfs_admin

 int
 guestfs_xfs_admin (guestfs_h *g,
                    const char *device,
                    ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_XFS_ADMIN_EXTUNWRITTEN, int extunwritten,
 GUESTFS_XFS_ADMIN_IMGFILE, int imgfile,
 GUESTFS_XFS_ADMIN_V2LOG, int v2log,
 GUESTFS_XFS_ADMIN_PROJID32BIT, int projid32bit,
 GUESTFS_XFS_ADMIN_LAZYCOUNTER, int lazycounter,
 GUESTFS_XFS_ADMIN_LABEL, const char *label,
 GUESTFS_XFS_ADMIN_UUID, const char *uuid,

Change the parameters of the XFS filesystem on device.

Devices that are mounted cannot be modified. Administrators must unmount filesystems before this call can modify parameters.

Some of the parameters of a mounted filesystem can be examined and modified using the guestfs_xfs_info and guestfs_xfs_growfs calls.

This function returns 0 on success or -1 on error.

(Added in 1.19.33)

guestfs_xfs_admin_va

 int
 guestfs_xfs_admin_va (guestfs_h *g,
                       const char *device,
                       va_list args);

This is the "va_list variant" of "guestfs_xfs_admin".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_xfs_admin_argv

 int
 guestfs_xfs_admin_argv (guestfs_h *g,
                         const char *device,
                         const struct guestfs_xfs_admin_argv *optargs);

This is the "argv variant" of "guestfs_xfs_admin".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_xfs_growfs

 int
 guestfs_xfs_growfs (guestfs_h *g,
                     const char *path,
                     ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_XFS_GROWFS_DATASEC, int datasec,
 GUESTFS_XFS_GROWFS_LOGSEC, int logsec,
 GUESTFS_XFS_GROWFS_RTSEC, int rtsec,
 GUESTFS_XFS_GROWFS_DATASIZE, int64_t datasize,
 GUESTFS_XFS_GROWFS_LOGSIZE, int64_t logsize,
 GUESTFS_XFS_GROWFS_RTSIZE, int64_t rtsize,
 GUESTFS_XFS_GROWFS_RTEXTSIZE, int64_t rtextsize,
 GUESTFS_XFS_GROWFS_MAXPCT, int maxpct,

Grow the XFS filesystem mounted at path.

The returned struct contains geometry information. Missing fields are returned as -1 (for numeric fields) or empty string.

This function returns 0 on success or -1 on error.

(Added in 1.19.28)

guestfs_xfs_growfs_va

 int
 guestfs_xfs_growfs_va (guestfs_h *g,
                        const char *path,
                        va_list args);

This is the "va_list variant" of "guestfs_xfs_growfs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_xfs_growfs_argv

 int
 guestfs_xfs_growfs_argv (guestfs_h *g,
                          const char *path,
                          const struct guestfs_xfs_growfs_argv *optargs);

This is the "argv variant" of "guestfs_xfs_growfs".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_xfs_info

 struct guestfs_xfsinfo *
 guestfs_xfs_info (guestfs_h *g,
                   const char *pathordevice);

pathordevice is a mounted XFS filesystem or a device containing an XFS filesystem. This command returns the geometry of the filesystem.

The returned struct contains geometry information. Missing fields are returned as -1 (for numeric fields) or empty string.

This function returns a struct guestfs_xfsinfo *, or NULL if there was an error. The caller must call guestfs_free_xfsinfo after use.

(Added in 1.19.21)

guestfs_xfs_repair

 int
 guestfs_xfs_repair (guestfs_h *g,
                     const char *device,
                     ...);

You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with -1 on its own. See "CALLS WITH OPTIONAL ARGUMENTS".

 GUESTFS_XFS_REPAIR_FORCELOGZERO, int forcelogzero,
 GUESTFS_XFS_REPAIR_NOMODIFY, int nomodify,
 GUESTFS_XFS_REPAIR_NOPREFETCH, int noprefetch,
 GUESTFS_XFS_REPAIR_FORCEGEOMETRY, int forcegeometry,
 GUESTFS_XFS_REPAIR_MAXMEM, int64_t maxmem,
 GUESTFS_XFS_REPAIR_IHASHSIZE, int64_t ihashsize,
 GUESTFS_XFS_REPAIR_BHASHSIZE, int64_t bhashsize,
 GUESTFS_XFS_REPAIR_AGSTRIDE, int64_t agstride,
 GUESTFS_XFS_REPAIR_LOGDEV, const char *logdev,
 GUESTFS_XFS_REPAIR_RTDEV, const char *rtdev,

Repair corrupt or damaged XFS filesystem on device.

The filesystem is specified using the device argument which should be the device name of the disk partition or volume containing the filesystem. If given the name of a block device, xfs_repair will attempt to find the raw device associated with the specified block device and will use the raw device instead.

Regardless, the filesystem to be repaired must be unmounted, otherwise, the resulting filesystem may be inconsistent or corrupt.

The returned status indicates whether filesystem corruption was detected (returns 1) or was not detected (returns 0).

On error this function returns -1.

(Added in 1.19.36)

guestfs_xfs_repair_va

 int
 guestfs_xfs_repair_va (guestfs_h *g,
                        const char *device,
                        va_list args);

This is the "va_list variant" of "guestfs_xfs_repair".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_xfs_repair_argv

 int
 guestfs_xfs_repair_argv (guestfs_h *g,
                          const char *device,
                          const struct guestfs_xfs_repair_argv *optargs);

This is the "argv variant" of "guestfs_xfs_repair".

See "CALLS WITH OPTIONAL ARGUMENTS".

guestfs_zegrep

 char **
 guestfs_zegrep (guestfs_h *g,
                 const char *regex,
                 const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external zegrep program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_zegrepi

 char **
 guestfs_zegrepi (guestfs_h *g,
                  const char *regex,
                  const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external zegrep -i program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_zero

 int
 guestfs_zero (guestfs_h *g,
               const char *device);

This command writes zeroes over the first few blocks of device.

How many blocks are zeroed isn't specified (but it's not enough to securely wipe the device). It should be sufficient to remove any partition tables, filesystem superblocks and so on.

If blocks are already zero, then this command avoids writing zeroes. This prevents the underlying device from becoming non-sparse or growing unnecessarily.

See also: guestfs_zero_device, guestfs_scrub_device, guestfs_is_zero_device

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.0.16)

guestfs_zero_device

 int
 guestfs_zero_device (guestfs_h *g,
                      const char *device);

This command writes zeroes over the entire device. Compare with guestfs_zero which just zeroes the first few blocks of a device.

If blocks are already zero, then this command avoids writing zeroes. This prevents the underlying device from becoming non-sparse or growing unnecessarily.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.3.1)

guestfs_zero_free_space

 int
 guestfs_zero_free_space (guestfs_h *g,
                          const char *directory);

Zero the free space in the filesystem mounted on directory. The filesystem must be mounted read-write.

The filesystem contents are not affected, but any free space in the filesystem is freed.

Free space is not "trimmed". You may want to call guestfs_fstrim either as an alternative to this, or after calling this, depending on your requirements.

This function returns 0 on success or -1 on error.

This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

(Added in 1.17.18)

guestfs_zerofree

 int
 guestfs_zerofree (guestfs_h *g,
                   const char *device);

This runs the zerofree program on device. This program claims to zero unused inodes and disk blocks on an ext2/3 filesystem, thus making it possible to compress the filesystem more effectively.

You should not run this program if the filesystem is mounted.

It is possible that using this program can damage the filesystem or data on the filesystem.

This function returns 0 on success or -1 on error.

(Added in 1.0.26)

guestfs_zfgrep

 char **
 guestfs_zfgrep (guestfs_h *g,
                 const char *pattern,
                 const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external zfgrep program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_zfgrepi

 char **
 guestfs_zfgrepi (guestfs_h *g,
                  const char *pattern,
                  const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external zfgrep -i program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_zfile

 char *
 guestfs_zfile (guestfs_h *g,
                const char *meth,
                const char *path);

This function is deprecated. In new code, use the "guestfs_file" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This command runs file after first decompressing path using method.

method must be one of gzip, compress or bzip2.

Since 1.0.63, use guestfs_file instead which can now process compressed files.

This function returns a string, or NULL on error. The caller must free the returned string after use.

(Added in 1.0.59)

guestfs_zgrep

 char **
 guestfs_zgrep (guestfs_h *g,
                const char *regex,
                const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external zgrep program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

guestfs_zgrepi

 char **
 guestfs_zgrepi (guestfs_h *g,
                 const char *regex,
                 const char *path);

This function is deprecated. In new code, use the "guestfs_grep" call instead.

Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions.

This calls the external zgrep -i program and returns the matching lines.

This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use.

Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3).

(Added in 1.0.66)

STRUCTURES

guestfs_int_bool

 struct guestfs_int_bool {
   int32_t i;
   int32_t b;
 };
 
 struct guestfs_int_bool_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_int_bool *val; /* Elements. */
 };

 int guestfs_compare_int_bool (const struct guestfs_int_bool *, const struct guestfs_int_bool *);
 int guestfs_compare_int_bool_list (const struct guestfs_int_bool_list *, const struct guestfs_int_bool_list *);
 
 struct guestfs_int_bool *guestfs_copy_int_bool (const struct guestfs_int_bool *);
 struct guestfs_int_bool_list *guestfs_copy_int_bool_list (const struct guestfs_int_bool_list *);
 
 void guestfs_free_int_bool (struct guestfs_int_bool *);
 void guestfs_free_int_bool_list (struct guestfs_int_bool_list *);

guestfs_lvm_pv

 struct guestfs_lvm_pv {
   char *pv_name;
   /* The next field is NOT nul-terminated, be careful when printing it: */
   char pv_uuid[32];
   char *pv_fmt;
   uint64_t pv_size;
   uint64_t dev_size;
   uint64_t pv_free;
   uint64_t pv_used;
   char *pv_attr;
   int64_t pv_pe_count;
   int64_t pv_pe_alloc_count;
   char *pv_tags;
   uint64_t pe_start;
   int64_t pv_mda_count;
   uint64_t pv_mda_free;
 };
 
 struct guestfs_lvm_pv_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_lvm_pv *val; /* Elements. */
 };

 int guestfs_compare_lvm_pv (const struct guestfs_lvm_pv *, const struct guestfs_lvm_pv *);
 int guestfs_compare_lvm_pv_list (const struct guestfs_lvm_pv_list *, const struct guestfs_lvm_pv_list *);
 
 struct guestfs_lvm_pv *guestfs_copy_lvm_pv (const struct guestfs_lvm_pv *);
 struct guestfs_lvm_pv_list *guestfs_copy_lvm_pv_list (const struct guestfs_lvm_pv_list *);
 
 void guestfs_free_lvm_pv (struct guestfs_lvm_pv *);
 void guestfs_free_lvm_pv_list (struct guestfs_lvm_pv_list *);

guestfs_lvm_vg

 struct guestfs_lvm_vg {
   char *vg_name;
   /* The next field is NOT nul-terminated, be careful when printing it: */
   char vg_uuid[32];
   char *vg_fmt;
   char *vg_attr;
   uint64_t vg_size;
   uint64_t vg_free;
   char *vg_sysid;
   uint64_t vg_extent_size;
   int64_t vg_extent_count;
   int64_t vg_free_count;
   int64_t max_lv;
   int64_t max_pv;
   int64_t pv_count;
   int64_t lv_count;
   int64_t snap_count;
   int64_t vg_seqno;
   char *vg_tags;
   int64_t vg_mda_count;
   uint64_t vg_mda_free;
 };
 
 struct guestfs_lvm_vg_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_lvm_vg *val; /* Elements. */
 };

 int guestfs_compare_lvm_vg (const struct guestfs_lvm_vg *, const struct guestfs_lvm_vg *);
 int guestfs_compare_lvm_vg_list (const struct guestfs_lvm_vg_list *, const struct guestfs_lvm_vg_list *);
 
 struct guestfs_lvm_vg *guestfs_copy_lvm_vg (const struct guestfs_lvm_vg *);
 struct guestfs_lvm_vg_list *guestfs_copy_lvm_vg_list (const struct guestfs_lvm_vg_list *);
 
 void guestfs_free_lvm_vg (struct guestfs_lvm_vg *);
 void guestfs_free_lvm_vg_list (struct guestfs_lvm_vg_list *);

guestfs_lvm_lv

 struct guestfs_lvm_lv {
   char *lv_name;
   /* The next field is NOT nul-terminated, be careful when printing it: */
   char lv_uuid[32];
   char *lv_attr;
   int64_t lv_major;
   int64_t lv_minor;
   int64_t lv_kernel_major;
   int64_t lv_kernel_minor;
   uint64_t lv_size;
   int64_t seg_count;
   char *origin;
   /* The next field is [0..100] or -1 meaning 'not present': */
   float snap_percent;
   /* The next field is [0..100] or -1 meaning 'not present': */
   float copy_percent;
   char *move_pv;
   char *lv_tags;
   char *mirror_log;
   char *modules;
 };
 
 struct guestfs_lvm_lv_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_lvm_lv *val; /* Elements. */
 };

 int guestfs_compare_lvm_lv (const struct guestfs_lvm_lv *, const struct guestfs_lvm_lv *);
 int guestfs_compare_lvm_lv_list (const struct guestfs_lvm_lv_list *, const struct guestfs_lvm_lv_list *);
 
 struct guestfs_lvm_lv *guestfs_copy_lvm_lv (const struct guestfs_lvm_lv *);
 struct guestfs_lvm_lv_list *guestfs_copy_lvm_lv_list (const struct guestfs_lvm_lv_list *);
 
 void guestfs_free_lvm_lv (struct guestfs_lvm_lv *);
 void guestfs_free_lvm_lv_list (struct guestfs_lvm_lv_list *);

guestfs_stat

 struct guestfs_stat {
   int64_t dev;
   int64_t ino;
   int64_t mode;
   int64_t nlink;
   int64_t uid;
   int64_t gid;
   int64_t rdev;
   int64_t size;
   int64_t blksize;
   int64_t blocks;
   int64_t atime;
   int64_t mtime;
   int64_t ctime;
 };
 
 struct guestfs_stat_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_stat *val; /* Elements. */
 };

 int guestfs_compare_stat (const struct guestfs_stat *, const struct guestfs_stat *);
 int guestfs_compare_stat_list (const struct guestfs_stat_list *, const struct guestfs_stat_list *);
 
 struct guestfs_stat *guestfs_copy_stat (const struct guestfs_stat *);
 struct guestfs_stat_list *guestfs_copy_stat_list (const struct guestfs_stat_list *);
 
 void guestfs_free_stat (struct guestfs_stat *);
 void guestfs_free_stat_list (struct guestfs_stat_list *);

guestfs_statvfs

 struct guestfs_statvfs {
   int64_t bsize;
   int64_t frsize;
   int64_t blocks;
   int64_t bfree;
   int64_t bavail;
   int64_t files;
   int64_t ffree;
   int64_t favail;
   int64_t fsid;
   int64_t flag;
   int64_t namemax;
 };
 
 struct guestfs_statvfs_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_statvfs *val; /* Elements. */
 };

 int guestfs_compare_statvfs (const struct guestfs_statvfs *, const struct guestfs_statvfs *);
 int guestfs_compare_statvfs_list (const struct guestfs_statvfs_list *, const struct guestfs_statvfs_list *);
 
 struct guestfs_statvfs *guestfs_copy_statvfs (const struct guestfs_statvfs *);
 struct guestfs_statvfs_list *guestfs_copy_statvfs_list (const struct guestfs_statvfs_list *);
 
 void guestfs_free_statvfs (struct guestfs_statvfs *);
 void guestfs_free_statvfs_list (struct guestfs_statvfs_list *);

guestfs_dirent

 struct guestfs_dirent {
   int64_t ino;
   char ftyp;
   char *name;
 };
 
 struct guestfs_dirent_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_dirent *val; /* Elements. */
 };

 int guestfs_compare_dirent (const struct guestfs_dirent *, const struct guestfs_dirent *);
 int guestfs_compare_dirent_list (const struct guestfs_dirent_list *, const struct guestfs_dirent_list *);
 
 struct guestfs_dirent *guestfs_copy_dirent (const struct guestfs_dirent *);
 struct guestfs_dirent_list *guestfs_copy_dirent_list (const struct guestfs_dirent_list *);
 
 void guestfs_free_dirent (struct guestfs_dirent *);
 void guestfs_free_dirent_list (struct guestfs_dirent_list *);

guestfs_version

 struct guestfs_version {
   int64_t major;
   int64_t minor;
   int64_t release;
   char *extra;
 };
 
 struct guestfs_version_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_version *val; /* Elements. */
 };

 int guestfs_compare_version (const struct guestfs_version *, const struct guestfs_version *);
 int guestfs_compare_version_list (const struct guestfs_version_list *, const struct guestfs_version_list *);
 
 struct guestfs_version *guestfs_copy_version (const struct guestfs_version *);
 struct guestfs_version_list *guestfs_copy_version_list (const struct guestfs_version_list *);
 
 void guestfs_free_version (struct guestfs_version *);
 void guestfs_free_version_list (struct guestfs_version_list *);

guestfs_xattr

 struct guestfs_xattr {
   char *attrname;
   /* The next two fields describe a byte array. */
   uint32_t attrval_len;
   char *attrval;
 };
 
 struct guestfs_xattr_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_xattr *val; /* Elements. */
 };

 int guestfs_compare_xattr (const struct guestfs_xattr *, const struct guestfs_xattr *);
 int guestfs_compare_xattr_list (const struct guestfs_xattr_list *, const struct guestfs_xattr_list *);
 
 struct guestfs_xattr *guestfs_copy_xattr (const struct guestfs_xattr *);
 struct guestfs_xattr_list *guestfs_copy_xattr_list (const struct guestfs_xattr_list *);
 
 void guestfs_free_xattr (struct guestfs_xattr *);
 void guestfs_free_xattr_list (struct guestfs_xattr_list *);

guestfs_inotify_event

 struct guestfs_inotify_event {
   int64_t in_wd;
   uint32_t in_mask;
   uint32_t in_cookie;
   char *in_name;
 };
 
 struct guestfs_inotify_event_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_inotify_event *val; /* Elements. */
 };

 int guestfs_compare_inotify_event (const struct guestfs_inotify_event *, const struct guestfs_inotify_event *);
 int guestfs_compare_inotify_event_list (const struct guestfs_inotify_event_list *, const struct guestfs_inotify_event_list *);
 
 struct guestfs_inotify_event *guestfs_copy_inotify_event (const struct guestfs_inotify_event *);
 struct guestfs_inotify_event_list *guestfs_copy_inotify_event_list (const struct guestfs_inotify_event_list *);
 
 void guestfs_free_inotify_event (struct guestfs_inotify_event *);
 void guestfs_free_inotify_event_list (struct guestfs_inotify_event_list *);

guestfs_partition

 struct guestfs_partition {
   int32_t part_num;
   uint64_t part_start;
   uint64_t part_end;
   uint64_t part_size;
 };
 
 struct guestfs_partition_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_partition *val; /* Elements. */
 };

 int guestfs_compare_partition (const struct guestfs_partition *, const struct guestfs_partition *);
 int guestfs_compare_partition_list (const struct guestfs_partition_list *, const struct guestfs_partition_list *);
 
 struct guestfs_partition *guestfs_copy_partition (const struct guestfs_partition *);
 struct guestfs_partition_list *guestfs_copy_partition_list (const struct guestfs_partition_list *);
 
 void guestfs_free_partition (struct guestfs_partition *);
 void guestfs_free_partition_list (struct guestfs_partition_list *);

guestfs_application

 struct guestfs_application {
   char *app_name;
   char *app_display_name;
   int32_t app_epoch;
   char *app_version;
   char *app_release;
   char *app_install_path;
   char *app_trans_path;
   char *app_publisher;
   char *app_url;
   char *app_source_package;
   char *app_summary;
   char *app_description;
 };
 
 struct guestfs_application_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_application *val; /* Elements. */
 };

 int guestfs_compare_application (const struct guestfs_application *, const struct guestfs_application *);
 int guestfs_compare_application_list (const struct guestfs_application_list *, const struct guestfs_application_list *);
 
 struct guestfs_application *guestfs_copy_application (const struct guestfs_application *);
 struct guestfs_application_list *guestfs_copy_application_list (const struct guestfs_application_list *);
 
 void guestfs_free_application (struct guestfs_application *);
 void guestfs_free_application_list (struct guestfs_application_list *);

guestfs_application2

 struct guestfs_application2 {
   char *app2_name;
   char *app2_display_name;
   int32_t app2_epoch;
   char *app2_version;
   char *app2_release;
   char *app2_arch;
   char *app2_install_path;
   char *app2_trans_path;
   char *app2_publisher;
   char *app2_url;
   char *app2_source_package;
   char *app2_summary;
   char *app2_description;
   char *app2_spare1;
   char *app2_spare2;
   char *app2_spare3;
   char *app2_spare4;
 };
 
 struct guestfs_application2_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_application2 *val; /* Elements. */
 };

 int guestfs_compare_application2 (const struct guestfs_application2 *, const struct guestfs_application2 *);
 int guestfs_compare_application2_list (const struct guestfs_application2_list *, const struct guestfs_application2_list *);
 
 struct guestfs_application2 *guestfs_copy_application2 (const struct guestfs_application2 *);
 struct guestfs_application2_list *guestfs_copy_application2_list (const struct guestfs_application2_list *);
 
 void guestfs_free_application2 (struct guestfs_application2 *);
 void guestfs_free_application2_list (struct guestfs_application2_list *);

guestfs_isoinfo

 struct guestfs_isoinfo {
   char *iso_system_id;
   char *iso_volume_id;
   uint32_t iso_volume_space_size;
   uint32_t iso_volume_set_size;
   uint32_t iso_volume_sequence_number;
   uint32_t iso_logical_block_size;
   char *iso_volume_set_id;
   char *iso_publisher_id;
   char *iso_data_preparer_id;
   char *iso_application_id;
   char *iso_copyright_file_id;
   char *iso_abstract_file_id;
   char *iso_bibliographic_file_id;
   int64_t iso_volume_creation_t;
   int64_t iso_volume_modification_t;
   int64_t iso_volume_expiration_t;
   int64_t iso_volume_effective_t;
 };
 
 struct guestfs_isoinfo_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_isoinfo *val; /* Elements. */
 };

 int guestfs_compare_isoinfo (const struct guestfs_isoinfo *, const struct guestfs_isoinfo *);
 int guestfs_compare_isoinfo_list (const struct guestfs_isoinfo_list *, const struct guestfs_isoinfo_list *);
 
 struct guestfs_isoinfo *guestfs_copy_isoinfo (const struct guestfs_isoinfo *);
 struct guestfs_isoinfo_list *guestfs_copy_isoinfo_list (const struct guestfs_isoinfo_list *);
 
 void guestfs_free_isoinfo (struct guestfs_isoinfo *);
 void guestfs_free_isoinfo_list (struct guestfs_isoinfo_list *);

guestfs_mdstat

 struct guestfs_mdstat {
   char *mdstat_device;
   int32_t mdstat_index;
   char *mdstat_flags;
 };
 
 struct guestfs_mdstat_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_mdstat *val; /* Elements. */
 };

 int guestfs_compare_mdstat (const struct guestfs_mdstat *, const struct guestfs_mdstat *);
 int guestfs_compare_mdstat_list (const struct guestfs_mdstat_list *, const struct guestfs_mdstat_list *);
 
 struct guestfs_mdstat *guestfs_copy_mdstat (const struct guestfs_mdstat *);
 struct guestfs_mdstat_list *guestfs_copy_mdstat_list (const struct guestfs_mdstat_list *);
 
 void guestfs_free_mdstat (struct guestfs_mdstat *);
 void guestfs_free_mdstat_list (struct guestfs_mdstat_list *);

guestfs_btrfssubvolume

 struct guestfs_btrfssubvolume {
   uint64_t btrfssubvolume_id;
   uint64_t btrfssubvolume_top_level_id;
   char *btrfssubvolume_path;
 };
 
 struct guestfs_btrfssubvolume_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_btrfssubvolume *val; /* Elements. */
 };

 int guestfs_compare_btrfssubvolume (const struct guestfs_btrfssubvolume *, const struct guestfs_btrfssubvolume *);
 int guestfs_compare_btrfssubvolume_list (const struct guestfs_btrfssubvolume_list *, const struct guestfs_btrfssubvolume_list *);
 
 struct guestfs_btrfssubvolume *guestfs_copy_btrfssubvolume (const struct guestfs_btrfssubvolume *);
 struct guestfs_btrfssubvolume_list *guestfs_copy_btrfssubvolume_list (const struct guestfs_btrfssubvolume_list *);
 
 void guestfs_free_btrfssubvolume (struct guestfs_btrfssubvolume *);
 void guestfs_free_btrfssubvolume_list (struct guestfs_btrfssubvolume_list *);

guestfs_xfsinfo

 struct guestfs_xfsinfo {
   char *xfs_mntpoint;
   uint32_t xfs_inodesize;
   uint32_t xfs_agcount;
   uint32_t xfs_agsize;
   uint32_t xfs_sectsize;
   uint32_t xfs_attr;
   uint32_t xfs_blocksize;
   uint64_t xfs_datablocks;
   uint32_t xfs_imaxpct;
   uint32_t xfs_sunit;
   uint32_t xfs_swidth;
   uint32_t xfs_dirversion;
   uint32_t xfs_dirblocksize;
   uint32_t xfs_cimode;
   char *xfs_logname;
   uint32_t xfs_logblocksize;
   uint32_t xfs_logblocks;
   uint32_t xfs_logversion;
   uint32_t xfs_logsectsize;
   uint32_t xfs_logsunit;
   uint32_t xfs_lazycount;
   char *xfs_rtname;
   uint32_t xfs_rtextsize;
   uint64_t xfs_rtblocks;
   uint64_t xfs_rtextents;
 };
 
 struct guestfs_xfsinfo_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_xfsinfo *val; /* Elements. */
 };

 int guestfs_compare_xfsinfo (const struct guestfs_xfsinfo *, const struct guestfs_xfsinfo *);
 int guestfs_compare_xfsinfo_list (const struct guestfs_xfsinfo_list *, const struct guestfs_xfsinfo_list *);
 
 struct guestfs_xfsinfo *guestfs_copy_xfsinfo (const struct guestfs_xfsinfo *);
 struct guestfs_xfsinfo_list *guestfs_copy_xfsinfo_list (const struct guestfs_xfsinfo_list *);
 
 void guestfs_free_xfsinfo (struct guestfs_xfsinfo *);
 void guestfs_free_xfsinfo_list (struct guestfs_xfsinfo_list *);

guestfs_utsname

 struct guestfs_utsname {
   char *uts_sysname;
   char *uts_release;
   char *uts_version;
   char *uts_machine;
 };
 
 struct guestfs_utsname_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_utsname *val; /* Elements. */
 };

 int guestfs_compare_utsname (const struct guestfs_utsname *, const struct guestfs_utsname *);
 int guestfs_compare_utsname_list (const struct guestfs_utsname_list *, const struct guestfs_utsname_list *);
 
 struct guestfs_utsname *guestfs_copy_utsname (const struct guestfs_utsname *);
 struct guestfs_utsname_list *guestfs_copy_utsname_list (const struct guestfs_utsname_list *);
 
 void guestfs_free_utsname (struct guestfs_utsname *);
 void guestfs_free_utsname_list (struct guestfs_utsname_list *);

guestfs_hivex_node

 struct guestfs_hivex_node {
   int64_t hivex_node_h;
 };
 
 struct guestfs_hivex_node_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_hivex_node *val; /* Elements. */
 };

 int guestfs_compare_hivex_node (const struct guestfs_hivex_node *, const struct guestfs_hivex_node *);
 int guestfs_compare_hivex_node_list (const struct guestfs_hivex_node_list *, const struct guestfs_hivex_node_list *);
 
 struct guestfs_hivex_node *guestfs_copy_hivex_node (const struct guestfs_hivex_node *);
 struct guestfs_hivex_node_list *guestfs_copy_hivex_node_list (const struct guestfs_hivex_node_list *);
 
 void guestfs_free_hivex_node (struct guestfs_hivex_node *);
 void guestfs_free_hivex_node_list (struct guestfs_hivex_node_list *);

guestfs_hivex_value

 struct guestfs_hivex_value {
   int64_t hivex_value_h;
 };
 
 struct guestfs_hivex_value_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_hivex_value *val; /* Elements. */
 };

 int guestfs_compare_hivex_value (const struct guestfs_hivex_value *, const struct guestfs_hivex_value *);
 int guestfs_compare_hivex_value_list (const struct guestfs_hivex_value_list *, const struct guestfs_hivex_value_list *);
 
 struct guestfs_hivex_value *guestfs_copy_hivex_value (const struct guestfs_hivex_value *);
 struct guestfs_hivex_value_list *guestfs_copy_hivex_value_list (const struct guestfs_hivex_value_list *);
 
 void guestfs_free_hivex_value (struct guestfs_hivex_value *);
 void guestfs_free_hivex_value_list (struct guestfs_hivex_value_list *);

guestfs_internal_mountable

 struct guestfs_internal_mountable {
   int32_t im_type;
   char *im_device;
   char *im_volume;
 };
 
 struct guestfs_internal_mountable_list {
   uint32_t len; /* Number of elements in list. */
   struct guestfs_internal_mountable *val; /* Elements. */
 };

 int guestfs_compare_internal_mountable (const struct guestfs_internal_mountable *, const struct guestfs_internal_mountable *);
 int guestfs_compare_internal_mountable_list (const struct guestfs_internal_mountable_list *, const struct guestfs_internal_mountable_list *);
 
 struct guestfs_internal_mountable *guestfs_copy_internal_mountable (const struct guestfs_internal_mountable *);
 struct guestfs_internal_mountable_list *guestfs_copy_internal_mountable_list (const struct guestfs_internal_mountable_list *);
 
 void guestfs_free_internal_mountable (struct guestfs_internal_mountable *);
 void guestfs_free_internal_mountable_list (struct guestfs_internal_mountable_list *);

AVAILABILITY

GROUPS OF FUNCTIONALITY IN THE APPLIANCE

Using "guestfs_available" you can test availability of the following groups of functions. This test queries the appliance to see if the appliance you are currently using supports the functionality.

acl

The following functions: "guestfs_acl_delete_def_file" "guestfs_acl_get_file" "guestfs_acl_set_file"

augeas

The following functions: "guestfs_aug_clear" "guestfs_aug_close" "guestfs_aug_defnode" "guestfs_aug_defvar" "guestfs_aug_get" "guestfs_aug_init" "guestfs_aug_insert" "guestfs_aug_label" "guestfs_aug_load" "guestfs_aug_ls" "guestfs_aug_match" "guestfs_aug_mv" "guestfs_aug_rm" "guestfs_aug_save" "guestfs_aug_set" "guestfs_aug_setm"

blkdiscard

The following functions: "guestfs_blkdiscard"

blkdiscardzeroes

The following functions: "guestfs_blkdiscardzeroes"

btrfs

The following functions: "guestfs_btrfs_device_add" "guestfs_btrfs_device_delete" "guestfs_btrfs_filesystem_balance" "guestfs_btrfs_filesystem_resize" "guestfs_btrfs_filesystem_sync" "guestfs_btrfs_fsck" "guestfs_btrfs_set_seeding" "guestfs_btrfs_subvolume_create" "guestfs_btrfs_subvolume_delete" "guestfs_btrfs_subvolume_list" "guestfs_btrfs_subvolume_set_default" "guestfs_btrfs_subvolume_snapshot" "guestfs_mkfs_btrfs"

extlinux

The following functions: "guestfs_extlinux"

fstrim

The following functions: "guestfs_fstrim"

gdisk

The following functions: "guestfs_part_get_gpt_type" "guestfs_part_get_name" "guestfs_part_set_gpt_type"

grub

The following functions: "guestfs_grub_install"

hivex

The following functions: "guestfs_hivex_close" "guestfs_hivex_commit" "guestfs_hivex_node_add_child" "guestfs_hivex_node_children" "guestfs_hivex_node_delete_child" "guestfs_hivex_node_get_child" "guestfs_hivex_node_get_value" "guestfs_hivex_node_name" "guestfs_hivex_node_parent" "guestfs_hivex_node_set_value" "guestfs_hivex_node_values" "guestfs_hivex_open" "guestfs_hivex_root" "guestfs_hivex_value_key" "guestfs_hivex_value_type" "guestfs_hivex_value_value"

inotify

The following functions: "guestfs_inotify_add_watch" "guestfs_inotify_close" "guestfs_inotify_files" "guestfs_inotify_init" "guestfs_inotify_read" "guestfs_inotify_rm_watch"

journal

The following functions: "guestfs_internal_journal_get" "guestfs_journal_close" "guestfs_journal_get_data_threshold" "guestfs_journal_next" "guestfs_journal_open" "guestfs_journal_set_data_threshold" "guestfs_journal_skip"

ldm

The following functions: "guestfs_ldmtool_create_all" "guestfs_ldmtool_diskgroup_disks" "guestfs_ldmtool_diskgroup_name" "guestfs_ldmtool_diskgroup_volumes" "guestfs_ldmtool_remove_all" "guestfs_ldmtool_scan" "guestfs_ldmtool_scan_devices" "guestfs_ldmtool_volume_hint" "guestfs_ldmtool_volume_partitions" "guestfs_ldmtool_volume_type" "guestfs_list_ldm_partitions" "guestfs_list_ldm_volumes"

linuxcaps

The following functions: "guestfs_cap_get_file" "guestfs_cap_set_file"

linuxfsuuid

The following functions: "guestfs_mke2fs_JU" "guestfs_mke2journal_U" "guestfs_mkswap_U" "guestfs_swapoff_uuid" "guestfs_swapon_uuid"

linuxmodules

The following functions: "guestfs_modprobe"

linuxxattrs

The following functions: "guestfs_getxattr" "guestfs_getxattrs" "guestfs_internal_lxattrlist" "guestfs_lgetxattr" "guestfs_lgetxattrs" "guestfs_lremovexattr" "guestfs_lsetxattr" "guestfs_removexattr" "guestfs_setxattr"

luks

The following functions: "guestfs_luks_add_key" "guestfs_luks_close" "guestfs_luks_format" "guestfs_luks_format_cipher" "guestfs_luks_kill_slot" "guestfs_luks_open" "guestfs_luks_open_ro"

lvm2

The following functions: "guestfs_lvcreate" "guestfs_lvcreate_free" "guestfs_lvm_remove_all" "guestfs_lvm_set_filter" "guestfs_lvremove" "guestfs_lvresize" "guestfs_lvresize_free" "guestfs_lvs" "guestfs_lvs_full" "guestfs_pvchange_uuid" "guestfs_pvchange_uuid_all" "guestfs_pvcreate" "guestfs_pvremove" "guestfs_pvresize" "guestfs_pvresize_size" "guestfs_pvs" "guestfs_pvs_full" "guestfs_vg_activate" "guestfs_vg_activate_all" "guestfs_vgchange_uuid" "guestfs_vgchange_uuid_all" "guestfs_vgcreate" "guestfs_vgmeta" "guestfs_vgremove" "guestfs_vgs" "guestfs_vgs_full"

mdadm

The following functions: "guestfs_md_create" "guestfs_md_detail" "guestfs_md_stat" "guestfs_md_stop"

mknod

The following functions: "guestfs_mkfifo" "guestfs_mknod" "guestfs_mknod_b" "guestfs_mknod_c"

ntfs3g

The following functions: "guestfs_ntfs_3g_probe" "guestfs_ntfsclone_in" "guestfs_ntfsclone_out" "guestfs_ntfsfix"

ntfsprogs

The following functions: "guestfs_ntfsresize" "guestfs_ntfsresize_size"

realpath

The following functions: "guestfs_realpath"

rsync

The following functions: "guestfs_rsync" "guestfs_rsync_in" "guestfs_rsync_out"

scrub

The following functions: "guestfs_scrub_device" "guestfs_scrub_file" "guestfs_scrub_freespace"

selinux

The following functions: "guestfs_getcon" "guestfs_setcon"

syslinux

The following functions: "guestfs_syslinux"

wipefs

The following functions: "guestfs_wipefs"

xfs

The following functions: "guestfs_xfs_admin" "guestfs_xfs_growfs" "guestfs_xfs_info" "guestfs_xfs_repair"

xz

The following functions: "guestfs_txz_in" "guestfs_txz_out"

zerofree

The following functions: "guestfs_zerofree"

FILESYSTEM AVAILABLE

The "guestfs_filesystem_available" call tests whether a filesystem type is supported by the appliance kernel.

This is mainly useful as a negative test. If this returns true, it doesn't mean that a particular filesystem can be mounted, since filesystems can fail for other reasons such as it being a later version of the filesystem, or having incompatible features.

GUESTFISH supported COMMAND

In guestfish(3) there is a handy interactive command supported which prints out the available groups and whether they are supported by this build of libguestfs. Note however that you have to do run first.

SINGLE CALLS AT COMPILE TIME

Since version 1.5.8, <guestfs.h> defines symbols for each C API function, such as:

 #define GUESTFS_HAVE_DD 1

if "guestfs_dd" is available.

Before version 1.5.8, if you needed to test whether a single libguestfs function is available at compile time, we recommended using build tools such as autoconf or cmake. For example in autotools you could use:

 AC_CHECK_LIB([guestfs],[guestfs_create])
 AC_CHECK_FUNCS([guestfs_dd])

which would result in HAVE_GUESTFS_DD being either defined or not defined in your program.

SINGLE CALLS AT RUN TIME

Testing at compile time doesn't guarantee that a function really exists in the library. The reason is that you might be dynamically linked against a previous libguestfs.so (dynamic library) which doesn't have the call. This situation unfortunately results in a segmentation fault, which is a shortcoming of the C dynamic linking system itself.

You can use dlopen(3) to test if a function is available at run time, as in this example program (note that you still need the compile time check as well):

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <dlfcn.h>
 #include <guestfs.h>
 
 main ()
 {
 #ifdef GUESTFS_HAVE_DD
   void *dl;
   int has_function;
 
   /* Test if the function guestfs_dd is really available. */
   dl = dlopen (NULL, RTLD_LAZY);
   if (!dl) {
     fprintf (stderr, "dlopen: %s\n", dlerror ());
     exit (EXIT_FAILURE);
   }
   has_function = dlsym (dl, "guestfs_dd") != NULL;
   dlclose (dl);
 
   if (!has_function)
     printf ("this libguestfs.so does NOT have guestfs_dd function\n");
   else {
     printf ("this libguestfs.so has guestfs_dd function\n");
     /* Now it's safe to call
     guestfs_dd (g, "foo", "bar");
     */
   }
 #else
   printf ("guestfs_dd function was not found at compile time\n");
 #endif
  }

You may think the above is an awful lot of hassle, and it is. There are other ways outside of the C linking system to ensure that this kind of incompatibility never arises, such as using package versioning:

 Requires: libguestfs >= 1.0.80

CALLS WITH OPTIONAL ARGUMENTS

A recent feature of the API is the introduction of calls which take optional arguments. In C these are declared 3 ways. The main way is as a call which takes variable arguments (ie. ...), as in this example:

 int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...);

Call this with a list of optional arguments, terminated by -1. So to call with no optional arguments specified:

 guestfs_add_drive_opts (g, filename, -1);

With a single optional argument:

 guestfs_add_drive_opts (g, filename,
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2",
                         -1);

With two:

 guestfs_add_drive_opts (g, filename,
                         GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2",
                         GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
                         -1);

and so forth. Don't forget the terminating -1 otherwise Bad Things will happen!

USING va_list FOR OPTIONAL ARGUMENTS

The second variant has the same name with the suffix _va, which works the same way but takes a va_list. See the C manual for details. For the example function, this is declared:

 int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename,
                                va_list args);

CONSTRUCTING OPTIONAL ARGUMENTS

The third variant is useful where you need to construct these calls. You pass in a structure where you fill in the optional fields. The structure has a bitmask as the first element which you must set to indicate which fields you have filled in. For our example function the structure and call are declared:

 struct guestfs_add_drive_opts_argv {
   uint64_t bitmask;
   int readonly;
   const char *format;
   /* ... */
 };
 int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename,
              const struct guestfs_add_drive_opts_argv *optargs);

You could call it like this:

 struct guestfs_add_drive_opts_argv optargs = {
   .bitmask = GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK |
              GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK,
   .readonly = 1,
   .format = "qcow2"
 };
 
 guestfs_add_drive_opts_argv (g, filename, &optargs);

Notes:

OPTIONAL ARGUMENTS IN OTHER LANGUAGES

In other languages, optional arguments are expressed in the way that is natural for that language. We refer you to the language-specific documentation for more details on that.

For guestfish, see "OPTIONAL ARGUMENTS" in guestfish(1).

EVENTS

SETTING CALLBACKS TO HANDLE EVENTS

Note: This section documents the generic event mechanism introduced in libguestfs 1.10, which you should use in new code if possible. The old functions guestfs_set_log_message_callback, guestfs_set_subprocess_quit_callback, guestfs_set_launch_done_callback, guestfs_set_close_callback and guestfs_set_progress_callback are no longer documented in this manual page. Because of the ABI guarantee, the old functions continue to work.

Handles generate events when certain things happen, such as log messages being generated, progress messages during long-running operations, or the handle being closed. The API calls described below let you register a callback to be called when events happen. You can register multiple callbacks (for the same, different or overlapping sets of events), and individually remove callbacks. If callbacks are not removed, then they remain in force until the handle is closed.

In the current implementation, events are only generated synchronously: that means that events (and hence callbacks) can only happen while you are in the middle of making another libguestfs call. The callback is called in the same thread.

Events may contain a payload, usually nothing (void), an array of 64 bit unsigned integers, or a message buffer. Payloads are discussed later on.

CLASSES OF EVENTS

GUESTFS_EVENT_CLOSE (payload type: void)

The callback function will be called while the handle is being closed (synchronously from "guestfs_close").

Note that libguestfs installs an atexit(3) handler to try to clean up handles that are open when the program exits. This means that this callback might be called indirectly from exit(3), which can cause unexpected problems in higher-level languages (eg. if your HLL interpreter has already been cleaned up by the time this is called, and if your callback then jumps into some HLL function).

If no callback is registered: the handle is closed without any callback being invoked.

GUESTFS_EVENT_SUBPROCESS_QUIT (payload type: void)

The callback function will be called when the child process quits, either asynchronously or if killed by "guestfs_kill_subprocess". (This corresponds to a transition from any state to the CONFIG state).

If no callback is registered: the event is ignored.

GUESTFS_EVENT_LAUNCH_DONE (payload type: void)

The callback function will be called when the child process becomes ready first time after it has been launched. (This corresponds to a transition from LAUNCHING to the READY state).

If no callback is registered: the event is ignored.

GUESTFS_EVENT_PROGRESS (payload type: array of 4 x uint64_t)

Some long-running operations can generate progress messages. If this callback is registered, then it will be called each time a progress message is generated (usually two seconds after the operation started, and three times per second thereafter until it completes, although the frequency may change in future versions).

The callback receives in the payload four unsigned 64 bit numbers which are (in order): proc_nr, serial, position, total.

The units of total are not defined, although for some operations total may relate in some way to the amount of data to be transferred (eg. in bytes or megabytes), and position may be the portion which has been transferred.

The only defined and stable parts of the API are:

The callback also receives the procedure number (proc_nr) and serial number (serial) of the call. These are only useful for debugging protocol issues, and the callback can normally ignore them. The callback may want to print these numbers in error messages or debugging messages.

If no callback is registered: progress messages are discarded.

GUESTFS_EVENT_APPLIANCE (payload type: message buffer)

The callback function is called whenever a log message is generated by qemu, the appliance kernel, guestfsd (daemon), or utility programs.

If the verbose flag ("guestfs_set_verbose") is set before launch ("guestfs_launch") then additional debug messages are generated.

If no callback is registered: the messages are discarded unless the verbose flag is set in which case they are sent to stderr. You can override the printing of verbose messages to stderr by setting up a callback.

GUESTFS_EVENT_LIBRARY (payload type: message buffer)

The callback function is called whenever a log message is generated by the library part of libguestfs.

If the verbose flag ("guestfs_set_verbose") is set then additional debug messages are generated.

If no callback is registered: the messages are discarded unless the verbose flag is set in which case they are sent to stderr. You can override the printing of verbose messages to stderr by setting up a callback.

GUESTFS_EVENT_WARNING (payload type: message buffer)

The callback function is called whenever a warning message is generated by the library part of libguestfs.

If no callback is registered: the messages are printed to stderr. You can override the printing of warning messages to stderr by setting up a callback.

GUESTFS_EVENT_TRACE (payload type: message buffer)

The callback function is called whenever a trace message is generated. This only applies if the trace flag ("guestfs_set_trace") is set.

If no callback is registered: the messages are sent to stderr. You can override the printing of trace messages to stderr by setting up a callback.

GUESTFS_EVENT_ENTER (payload type: function name)

The callback function is called whenever a libguestfs function is entered.

The payload is a string which contains the name of the function that we are entering (not including guestfs_ prefix).

Note that libguestfs functions can call themselves, so you may see many events from a single call. A few libguestfs functions do not generate this event.

If no callback is registered: the event is ignored.

GUESTFS_EVENT_LIBVIRT_AUTH (payload type: libvirt URI)

For any API function that opens a libvirt connection, this event may be generated to indicate that libvirt demands authentication information. See "LIBVIRT AUTHENTICATION" below.

If no callback is registered: virConnectAuthPtrDefault is used (suitable for command-line programs only).

EVENT API

guestfs_set_event_callback

 int guestfs_set_event_callback (guestfs_h *g,
                                 guestfs_event_callback cb,
                                 uint64_t event_bitmask,
                                 int flags,
                                 void *opaque);

This function registers a callback (cb) for all event classes in the event_bitmask.

For example, to register for all log message events, you could call this function with the bitmask GUESTFS_EVENT_APPLIANCE|GUESTFS_EVENT_LIBRARY|GUESTFS_EVENT_WARNING. To register a single callback for all possible classes of events, use GUESTFS_EVENT_ALL.

flags should always be passed as 0.

opaque is an opaque pointer which is passed to the callback. You can use it for any purpose.

The return value is the event handle (an integer) which you can use to delete the callback (see below).

If there is an error, this function returns -1, and sets the error in the handle in the usual way (see "guestfs_last_error" etc.)

Callbacks remain in effect until they are deleted, or until the handle is closed.

In the case where multiple callbacks are registered for a particular event class, all of the callbacks are called. The order in which multiple callbacks are called is not defined.

guestfs_delete_event_callback

 void guestfs_delete_event_callback (guestfs_h *g, int event_handle);

Delete a callback that was previously registered. event_handle should be the integer that was returned by a previous call to guestfs_set_event_callback on the same handle.

guestfs_event_to_string

 char *guestfs_event_to_string (uint64_t event);

event is either a single event or a bitmask of events. This returns a string representation (useful for debugging or printing events).

A single event is returned as the name in lower case, eg. "close".

A bitmask of several events is returned as a comma-separated list, eg. "close,progress".

If zero is passed, then the empty string "" is returned.

On success this returns a string. On error it returns NULL and sets errno.

The returned string must be freed by the caller.

guestfs_event_callback

 typedef void (*guestfs_event_callback) (
                  guestfs_h *g,
                  void *opaque,
                  uint64_t event,
                  int event_handle,
                  int flags,
                  const char *buf, size_t buf_len,
                  const uint64_t *array, size_t array_len);

This is the type of the event callback function that you have to provide.

The basic parameters are: the handle (g), the opaque user pointer (opaque), the event class (eg. GUESTFS_EVENT_PROGRESS), the event handle, and flags which in the current API you should ignore.

The remaining parameters contain the event payload (if any). Each event may contain a payload, which usually relates to the event class, but for future proofing your code should be written to handle any payload for any event class.

buf and buf_len contain a message buffer (if buf_len == 0, then there is no message buffer). Note that this message buffer can contain arbitrary 8 bit data, including NUL bytes.

array and array_len is an array of 64 bit unsigned integers. At the moment this is only used for progress messages.

EXAMPLE: CAPTURING LOG MESSAGES

A working program demonstrating this can be found in examples/debug-logging.c in the source of libguestfs.

One motivation for the generic event API was to allow GUI programs to capture debug and other messages. In libguestfs ≤ 1.8 these were sent unconditionally to stderr.

Events associated with log messages are: GUESTFS_EVENT_LIBRARY, GUESTFS_EVENT_APPLIANCE, GUESTFS_EVENT_WARNING and GUESTFS_EVENT_TRACE. (Note that error messages are not events; you must capture error messages separately).

Programs have to set up a callback to capture the classes of events of interest:

 int eh =
   guestfs_set_event_callback
     (g, message_callback,
      GUESTFS_EVENT_LIBRARY | GUESTFS_EVENT_APPLIANCE |
      GUESTFS_EVENT_WARNING | GUESTFS_EVENT_TRACE,
      0, NULL) == -1)
 if (eh == -1) {
   // handle error in the usual way
 }

The callback can then direct messages to the appropriate place. In this example, messages are directed to syslog:

 static void
 message_callback (
         guestfs_h *g,
         void *opaque,
         uint64_t event,
         int event_handle,
         int flags,
         const char *buf, size_t buf_len,
         const uint64_t *array, size_t array_len)
 {
   const int priority = LOG_USER|LOG_INFO;
   if (buf_len > 0)
     syslog (priority, "event 0x%lx: %s", event, buf);
 }

LIBVIRT AUTHENTICATION

Some libguestfs API calls can open libvirt connections. Currently the only ones are "guestfs_add_domain"; and "guestfs_launch" if the libvirt backend has been selected. Libvirt connections may require authentication, for example if they need to access a remote server or to access root services from non-root. Libvirt authentication happens via a callback mechanism, see http://libvirt.org/guide/html/Application_Development_Guide-Connections.html

You may provide libvirt authentication data by registering a callback for events of type GUESTFS_EVENT_LIBVIRT_AUTH.

If no such event is registered, then libguestfs uses a libvirt function that provides command-line prompts (virConnectAuthPtrDefault). This is only suitable for command-line libguestfs programs.

To provide authentication, first call "guestfs_set_libvirt_supported_credentials" with the list of credentials your program knows how to provide. Second, register a callback for the GUESTFS_EVENT_LIBVIRT_AUTH event. The event handler will be called when libvirt is requesting authentication information.

In the event handler, call "guestfs_get_libvirt_requested_credentials" to get a list of the credentials that libvirt is asking for. You then need to ask (eg. the user) for each credential, and call "guestfs_set_libvirt_requested_credential" with the answer. Note that for each credential, additional information may be available via the calls "guestfs_get_libvirt_requested_credential_prompt", "guestfs_get_libvirt_requested_credential_challenge" or "guestfs_get_libvirt_requested_credential_defresult".

The example program below should make this clearer.

There is also a more substantial working example program supplied with the libguestfs sources, called libvirt-auth.c.

 main ()
 {
   guestfs_h *g;
   char *creds[] = { "authname", "passphrase", NULL };
   int r, eh;
 
   g = guestfs_create ();
   if (!g) exit (EXIT_FAILURE);
 
   /* Tell libvirt what credentials the program supports. */
   r = guestfs_set_libvirt_supported_credentials (g, creds);
   if (r == -1)
     exit (EXIT_FAILURE);
 
   /* Set up the event handler. */
   eh = guestfs_set_event_callback (
       g, do_auth,
       GUESTFS_EVENT_LIBVIRT_AUTH, 0, NULL);
   if (eh == -1)
     exit (EXIT_FAILURE);
 
   /* An example of a call that may ask for credentials. */
   r = guestfs_add_domain (
       g, "dom",
       GUESTFS_ADD_DOMAIN_LIBVIRTURI, "qemu:///system",
       -1);
   if (r == -1)
     exit (EXIT_FAILURE);
 
   exit (EXIT_SUCCESS);
 }
 
 static void
 do_auth (guestfs_h *g,
          void *opaque,
          uint64_t event,
          int event_handle,
          int flags,
          const char *buf, size_t buf_len,
          const uint64_t *array, size_t array_len)
 {
   char **creds;
   size_t i;
   char *prompt;
   char *reply;
   size_t replylen;
   int r;
 
   // buf will be the libvirt URI.  buf_len may be ignored.
   printf ("Authentication required for libvirt conn '%s'\n",
           buf);
 
   // Ask libguestfs what credentials libvirt is demanding.
   creds = guestfs_get_libvirt_requested_credentials (g);
   if (creds == NULL)
     exit (EXIT_FAILURE);
 
   // Now ask the user for answers.
   for (i = 0; creds[i] != NULL; ++i)
   {
     if (strcmp (creds[i], "authname") == 0 ||
         strcmp (creds[i], "passphrase") == 0)
     {
       prompt =
         guestfs_get_libvirt_requested_credential_prompt (g, i);
       if (prompt && strcmp (prompt, "") != 0)
         printf ("%s: ", prompt);
       free (prompt);
 
       // Some code here to ask for the credential.
       // ...
       // Put the reply in 'reply', length 'replylen' (bytes).
 
      r = guestfs_set_libvirt_requested_credential (g, i,
          reply, replylen);
      if (r == -1)
        exit (EXIT_FAILURE);
     }
 
     free (creds[i]);
   }
 
   free (creds);
 }

CANCELLING LONG TRANSFERS

Some operations can be cancelled by the caller while they are in progress. Currently only operations that involve uploading or downloading data can be cancelled (technically: operations that have FileIn or FileOut parameters in the generator).

To cancel the transfer, call "guestfs_user_cancel". For more information, read the description of "guestfs_user_cancel".

PRIVATE DATA AREA

You can attach named pieces of private data to the libguestfs handle, fetch them by name, and walk over them, for the lifetime of the handle. This is called the private data area and is only available from the C API.

To attach a named piece of data, use the following call:

 void guestfs_set_private (guestfs_h *g, const char *key, void *data);

key is the name to associate with this data, and data is an arbitrary pointer (which can be NULL). Any previous item with the same key is overwritten.

You can use any key string you want, but avoid keys beginning with an underscore character (libguestfs uses those for its own internal purposes, such as implementing language bindings). It is recommended that you prefix the key with some unique string to avoid collisions with other users.

To retrieve the pointer, use:

 void *guestfs_get_private (guestfs_h *g, const char *key);

This function returns NULL if either no data is found associated with key, or if the user previously set the key's data pointer to NULL.

Libguestfs does not try to look at or interpret the data pointer in any way. As far as libguestfs is concerned, it need not be a valid pointer at all. In particular, libguestfs does not try to free the data when the handle is closed. If the data must be freed, then the caller must either free it before calling "guestfs_close" or must set up a close callback to do it (see "GUESTFS_EVENT_CLOSE").

To walk over all entries, use these two functions:

 void *guestfs_first_private (guestfs_h *g, const char **key_rtn);

 void *guestfs_next_private (guestfs_h *g, const char **key_rtn);

guestfs_first_private returns the first key, pointer pair ("first" does not have any particular meaning -- keys are not returned in any defined order). A pointer to the key is returned in *key_rtn and the corresponding data pointer is returned from the function. NULL is returned if there are no keys stored in the handle.

guestfs_next_private returns the next key, pointer pair. The return value of this function is NULL if there are no further entries to return.

Notes about walking over entries:

The following example code shows how to print all keys and data pointers that are associated with the handle g:

 const char *key;
 void *data = guestfs_first_private (g, &key);
 while (data != NULL)
   {
     printf ("key = %s, data = %p\n", key, data);
     data = guestfs_next_private (g, &key);
   }

More commonly you are only interested in keys that begin with an application-specific prefix foo_. Modify the loop like so:

 const char *key;
 void *data = guestfs_first_private (g, &key);
 while (data != NULL)
   {
     if (strncmp (key, "foo_", strlen ("foo_")) == 0)
       printf ("key = %s, data = %p\n", key, data);
     data = guestfs_next_private (g, &key);
   }

If you need to modify keys while walking, then you have to jump back to the beginning of the loop. For example, to delete all keys prefixed with foo_:

  const char *key;
  void *data;
 again:
  data = guestfs_first_private (g, &key);
  while (data != NULL)
    {
      if (strncmp (key, "foo_", strlen ("foo_")) == 0)
        {
          guestfs_set_private (g, key, NULL);
          /* note that 'key' pointer is now invalid, and so is
             the internal iterator */
          goto again;
        }
      data = guestfs_next_private (g, &key);
    }

Note that the above loop is guaranteed to terminate because the keys are being deleted, but other manipulations of keys within the loop might not terminate unless you also maintain an indication of which keys have been visited.

SYSTEMTAP

The libguestfs C library can be probed using systemtap or DTrace. This is true of any library, not just libguestfs. However libguestfs also contains static markers to help in probing internal operations.

You can list all the static markers by doing:

 stap -l 'process("/usr/lib*/libguestfs.so.0")
              .provider("guestfs").mark("*")'

Note: These static markers are not part of the stable API and may change in future versions.

SYSTEMTAP SCRIPT EXAMPLE

This script contains examples of displaying both the static markers and some ordinary C entry points:

 global last;
 
 function display_time () {
       now = gettimeofday_us ();
       delta = 0;
       if (last > 0)
             delta = now - last;
       last = now;
 
       printf ("%d (+%d):", now, delta);
 }
 
 probe begin {
       last = 0;
       printf ("ready\n");
 }
 
 /* Display all calls to static markers. */
 probe process("/usr/lib*/libguestfs.so.0")
           .provider("guestfs").mark("*") ? {
       display_time();
       printf ("\t%s %s\n", $$name, $$parms);
 }
 
 /* Display all calls to guestfs_mkfs* functions. */
 probe process("/usr/lib*/libguestfs.so.0")
           .function("guestfs_mkfs*") ? {
       display_time();
       printf ("\t%s %s\n", probefunc(), $$parms);
 }

The script above can be saved to test.stap and run using the stap(1) program. Note that you either have to be root, or you have to add yourself to several special stap groups. Consult the systemtap documentation for more information.

 # stap /tmp/test.stap
 ready

In another terminal, run a guestfish command such as this:

 guestfish -N fs

In the first terminal, stap trace output similar to this is shown:

 1318248056692655 (+0): launch_start
 1318248056692850 (+195):       launch_build_appliance_start
 1318248056818285 (+125435):    launch_build_appliance_end
 1318248056838059 (+19774):     launch_run_qemu
 1318248061071167 (+4233108):   launch_end
 1318248061280324 (+209157):    guestfs_mkfs g=0x1024ab0 fstype=0x46116f device=0x1024e60

ARCHITECTURE

Internally, libguestfs is implemented by running an appliance (a special type of small virtual machine) using qemu(1). Qemu runs as a child process of the main program.

  ___________________
 /                   \
 | main program      |
 |                   |
 |                   |           child process / appliance
 |                   |           __________________________
 |                   |          / qemu                     \
 +-------------------+   RPC    |      +-----------------+ |
 | libguestfs     <--------------------> guestfsd        | |
 |                   |          |      +-----------------+ |
 \___________________/          |      | Linux kernel    | |
                                |      +--^--------------+ |
                                \_________|________________/
                                          |
                                   _______v______
                                  /              \
                                  | Device or    |
                                  | disk image   |
                                  \______________/

The library, linked to the main program, creates the child process and hence the appliance in the "guestfs_launch" function.

Inside the appliance is a Linux kernel and a complete stack of userspace tools (such as LVM and ext2 programs) and a small controlling daemon called "guestfsd". The library talks to "guestfsd" using remote procedure calls (RPC). There is a mostly one-to-one correspondence between libguestfs API calls and RPC calls to the daemon. Lastly the disk image(s) are attached to the qemu process which translates device access by the appliance's Linux kernel into accesses to the image.

A common misunderstanding is that the appliance "is" the virtual machine. Although the disk image you are attached to might also be used by some virtual machine, libguestfs doesn't know or care about this. (But you will care if both libguestfs's qemu process and your virtual machine are trying to update the disk image at the same time, since these usually results in massive disk corruption).

STATE MACHINE

libguestfs uses a state machine to model the child process:

                         |
          guestfs_create / guestfs_create_flags
                         |
                         |
                     ____V_____
                    /          \
                    |  CONFIG  |
                    \__________/
                       ^   ^  \
                       |    \  \ guestfs_launch
                       |    _\__V______
                       |   /           \
                       |   | LAUNCHING |
                       |   \___________/
                       |       /
                       |  guestfs_launch
                       |     /
                     __|____V
                    /        \
                    | READY  |
                    \________/

The normal transitions are (1) CONFIG (when the handle is created, but there is no child process), (2) LAUNCHING (when the child process is booting up), (3) READY meaning the appliance is up, actions can be issued to, and carried out by, the child process.

The guest may be killed by "guestfs_kill_subprocess", or may die asynchronously at any time (eg. due to some internal error), and that causes the state to transition back to CONFIG.

Configuration commands for qemu such as "guestfs_set_path" can only be issued when in the CONFIG state.

The API offers one call that goes from CONFIG through LAUNCHING to READY. "guestfs_launch" blocks until the child process is READY to accept commands (or until some failure or timeout). "guestfs_launch" internally moves the state from CONFIG to LAUNCHING while it is running.

API actions such as "guestfs_mount" can only be issued when in the READY state. These API calls block waiting for the command to be carried out. There are no non-blocking versions, and no way to issue more than one command per handle at the same time.

Finally, the child process sends asynchronous messages back to the main program, such as kernel log messages. You can register a callback to receive these messages.

INTERNALS

APPLIANCE BOOT PROCESS

This process has evolved and continues to evolve. The description here corresponds only to the current version of libguestfs and is provided for information only.

In order to follow the stages involved below, enable libguestfs debugging (set the environment variable LIBGUESTFS_DEBUG=1).

Create the appliance

supermin --build is invoked to create the kernel, a small initrd and the appliance.

The appliance is cached in /var/tmp/.guestfs-<UID> (or in another directory if LIBGUESTFS_CACHEDIR or TMPDIR are set).

For a complete description of how the appliance is created and cached, read the supermin(1) man page.

Start qemu and boot the kernel

qemu is invoked to boot the kernel.

Run the initrd

supermin --build builds a small initrd. The initrd is not the appliance. The purpose of the initrd is to load enough kernel modules in order that the appliance itself can be mounted and started.

The initrd is a cpio archive called /var/tmp/.guestfs-<UID>/appliance.d/initrd.

When the initrd has started you will see messages showing that kernel modules are being loaded, similar to this:

 supermin: ext2 mini initrd starting up
 supermin: mounting /sys
 supermin: internal insmod libcrc32c.ko
 supermin: internal insmod crc32c-intel.ko
Find and mount the appliance device

The appliance is a sparse file containing an ext2 filesystem which contains a familiar (although reduced in size) Linux operating system. It would normally be called /var/tmp/.guestfs-<UID>/appliance.d/root.

The regular disks being inspected by libguestfs are the first devices exposed by qemu (eg. as /dev/vda).

The last disk added to qemu is the appliance itself (eg. /dev/vdb if there was only one regular disk).

Thus the final job of the initrd is to locate the appliance disk, mount it, and switch root into the appliance, and run /init from the appliance.

If this works successfully you will see messages such as:

 supermin: picked /sys/block/vdb/dev as root device
 supermin: creating /dev/root as block special 252:16
 supermin: mounting new root on /root
 supermin: chroot
 Starting /init script ...

Note that Starting /init script ... indicates that the appliance's init script is now running.

Initialize the appliance

The appliance itself now initializes itself. This involves starting certain processes like udev, possibly printing some debug information, and finally running the daemon (guestfsd).

The daemon

Finally the daemon (guestfsd) runs inside the appliance. If it runs you should see:

 verbose daemon enabled

The daemon expects to see a named virtio-serial port exposed by qemu and connected on the other end to the library.

The daemon connects to this port (and hence to the library) and sends a four byte message GUESTFS_LAUNCH_FLAG, which initiates the communication protocol (see below).

COMMUNICATION PROTOCOL

Don't rely on using this protocol directly. This section documents how it currently works, but it may change at any time.

The protocol used to talk between the library and the daemon running inside the qemu virtual machine is a simple RPC mechanism built on top of XDR (RFC 1014, RFC 1832, RFC 4506).

The detailed format of structures is in src/guestfs_protocol.x (note: this file is automatically generated).

There are two broad cases, ordinary functions that don't have any FileIn and FileOut parameters, which are handled with very simple request/reply messages. Then there are functions that have any FileIn or FileOut parameters, which use the same request and reply messages, but they may also be followed by files sent using a chunked encoding.

ORDINARY FUNCTIONS (NO FILEIN/FILEOUT PARAMS)

For ordinary functions, the request message is:

 total length (header + arguments,
      but not including the length word itself)
 struct guestfs_message_header (encoded as XDR)
 struct guestfs_<foo>_args (encoded as XDR)

The total length field allows the daemon to allocate a fixed size buffer into which it slurps the rest of the message. As a result, the total length is limited to GUESTFS_MESSAGE_MAX bytes (currently 4MB), which means the effective size of any request is limited to somewhere under this size.

Note also that many functions don't take any arguments, in which case the guestfs_foo_args is completely omitted.

The header contains the procedure number (guestfs_proc) which is how the receiver knows what type of args structure to expect, or none at all.

For functions that take optional arguments, the optional arguments are encoded in the guestfs_foo_args structure in the same way as ordinary arguments. A bitmask in the header indicates which optional arguments are meaningful. The bitmask is also checked to see if it contains bits set which the daemon does not know about (eg. if more optional arguments were added in a later version of the library), and this causes the call to be rejected.

The reply message for ordinary functions is:

 total length (header + ret,
      but not including the length word itself)
 struct guestfs_message_header (encoded as XDR)
 struct guestfs_<foo>_ret (encoded as XDR)

As above the guestfs_foo_ret structure may be completely omitted for functions that return no formal return values.

As above the total length of the reply is limited to GUESTFS_MESSAGE_MAX.

In the case of an error, a flag is set in the header, and the reply message is slightly changed:

 total length (header + error,
      but not including the length word itself)
 struct guestfs_message_header (encoded as XDR)
 struct guestfs_message_error (encoded as XDR)

The guestfs_message_error structure contains the error message as a string.

FUNCTIONS THAT HAVE FILEIN PARAMETERS

A FileIn parameter indicates that we transfer a file into the guest. The normal request message is sent (see above). However this is followed by a sequence of file chunks.

 total length (header + arguments,
      but not including the length word itself,
      and not including the chunks)
 struct guestfs_message_header (encoded as XDR)
 struct guestfs_<foo>_args (encoded as XDR)
 sequence of chunks for FileIn param #0
 sequence of chunks for FileIn param #1 etc.

The "sequence of chunks" is:

 length of chunk (not including length word itself)
 struct guestfs_chunk (encoded as XDR)
 length of chunk
 struct guestfs_chunk (encoded as XDR)
   ...
 length of chunk
 struct guestfs_chunk (with data.data_len == 0)

The final chunk has the data_len field set to zero. Additionally a flag is set in the final chunk to indicate either successful completion or early cancellation.

At time of writing there are no functions that have more than one FileIn parameter. However this is (theoretically) supported, by sending the sequence of chunks for each FileIn parameter one after another (from left to right).

Both the library (sender) and the daemon (receiver) may cancel the transfer. The library does this by sending a chunk with a special flag set to indicate cancellation. When the daemon sees this, it cancels the whole RPC, does not send any reply, and goes back to reading the next request.

The daemon may also cancel. It does this by writing a special word GUESTFS_CANCEL_FLAG to the socket. The library listens for this during the transfer, and if it gets it, it will cancel the transfer (it sends a cancel chunk). The special word is chosen so that even if cancellation happens right at the end of the transfer (after the library has finished writing and has started listening for the reply), the "spurious" cancel flag will not be confused with the reply message.

This protocol allows the transfer of arbitrary sized files (no 32 bit limit), and also files where the size is not known in advance (eg. from pipes or sockets). However the chunks are rather small (GUESTFS_MAX_CHUNK_SIZE), so that neither the library nor the daemon need to keep much in memory.

FUNCTIONS THAT HAVE FILEOUT PARAMETERS

The protocol for FileOut parameters is exactly the same as for FileIn parameters, but with the roles of daemon and library reversed.

 total length (header + ret,
      but not including the length word itself,
      and not including the chunks)
 struct guestfs_message_header (encoded as XDR)
 struct guestfs_<foo>_ret (encoded as XDR)
 sequence of chunks for FileOut param #0
 sequence of chunks for FileOut param #1 etc.

INITIAL MESSAGE

When the daemon launches it sends an initial word (GUESTFS_LAUNCH_FLAG) which indicates that the guest and daemon is alive. This is what "guestfs_launch" waits for.

PROGRESS NOTIFICATION MESSAGES

The daemon may send progress notification messages at any time. These are distinguished by the normal length word being replaced by GUESTFS_PROGRESS_FLAG, followed by a fixed size progress message.

The library turns them into progress callbacks (see "GUESTFS_EVENT_PROGRESS") if there is a callback registered, or discards them if not.

The daemon self-limits the frequency of progress messages it sends (see daemon/proto.c:notify_progress). Not all calls generate progress messages.

LIBGUESTFS VERSION NUMBERS

Since April 2010, libguestfs has started to make separate development and stable releases, along with corresponding branches in our git repository. These separate releases can be identified by version number:

                 even numbers for stable: 1.2.x, 1.4.x, ...
       .-------- odd numbers for development: 1.3.x, 1.5.x, ...
       |
       v
 1  .  3  .  5
 ^           ^
 |           |
 |           `-------- sub-version
 |
 `------ always '1' because we don't change the ABI

Thus "1.3.5" is the 5th update to the development branch "1.3".

As time passes we cherry pick fixes from the development branch and backport those into the stable branch, the effect being that the stable branch should get more stable and less buggy over time. So the stable releases are ideal for people who don't need new features but would just like the software to work.

Our criteria for backporting changes are:

A new stable branch starts when we think the new features in development are substantial and compelling enough over the current stable branch to warrant it. When that happens we create new stable and development versions 1.N.0 and 1.(N+1).0 [N is even]. The new dot-oh release won't necessarily be so stable at this point, but by backporting fixes from development, that branch will stabilize over time.

EXTENDING LIBGUESTFS

This section is for hackers who want to extend libguestfs itself.

OVERVIEW OF THE SOURCE CODE

Libguestfs source is located in the github repository https://github.com/libguestfs/libguestfs

Large amounts of boilerplate code in libguestfs (RPC, bindings, documentation) are generated. This means that many source files will appear to be missing from a straightforward git checkout. You have to run the generator (./autogen.sh && make -C generator) in order to create those files.

Libguestfs uses an autotools-based build system, with the main files being configure.ac and Makefile.am. The generator subdirectory contains the generator, plus files describing the API. The src subdirectory contains source for the library. The appliance and daemon subdirectories contain the source for the code that builds the appliance, and the code that runs in the appliance respectively. Other directories are covered in the section "SOURCE CODE SUBDIRECTORIES" below.

Apart from the fact that all API entry points go via some generated code, the library is straightforward. (In fact, even the generated code is designed to be readable, and should be read as ordinary code). Some actions run entirely in the library, and are written as C functions in files under src. Others are forwarded to the daemon where (after some generated RPC marshalling) they appear as C functions in files under daemon.

To build from source, first read the README file.

local* FILES

Files in the top source directory that begin with the prefix local* are ignored by git. These files can contain local configuration or scripts that you need to build libguestfs.

By convention, I have a file called localconfigure which is a simple wrapper around autogen.sh containing local configure customizations that I need:

 . localenv
 ./autogen.sh \
     --with-default-backend=libvirt \
     --enable-gcc-warnings \
     --enable-gtk-doc \
     -C \
     "$@"

So I can use this to build libguestfs:

 ./localconfigure && make

If there is a file in the top build directory called localenv, then it will be sourced by make. This file can contain any local environment variables needed, eg. for skipping tests:

 # Use an alternate python binary.
 export PYTHON=python3
 # Skip this test, it is broken.
 export SKIP_TEST_BTRFS_FSCK=1

Note that localenv is included by the top Makefile (so it's a Makefile fragment). But if it is also sourced by your localconfigure script then it is used as a shell script.

ADDING A NEW API ACTION

Because large amounts of boilerplate code in libguestfs are generated, this makes it easy to extend the libguestfs API.

To add a new API action there are two changes:

  1. You need to add a description of the call (name, parameters, return type, tests, documentation) to generator/actions.ml.

    There are two sorts of API action, depending on whether the call goes through to the daemon in the appliance, or is serviced entirely by the library (see "ARCHITECTURE" above). "guestfs_sync" is an example of the former, since the sync is done in the appliance. "guestfs_set_trace" is an example of the latter, since a trace flag is maintained in the handle and all tracing is done on the library side.

    Most new actions are of the first type, and get added to the daemon_functions list. Each function has a unique procedure number used in the RPC protocol which is assigned to that action when we publish libguestfs and cannot be reused. Take the latest procedure number and increment it.

    For library-only actions of the second type, add to the non_daemon_functions list. Since these functions are serviced by the library and do not travel over the RPC mechanism to the daemon, these functions do not need a procedure number, and so the procedure number is set to -1.

  2. Implement the action (in C):

    For daemon actions, implement the function do_<name> in the daemon/ directory.

    For library actions, implement the function guestfs__<name> (note: double underscore) in the src/ directory.

    In either case, use another function as an example of what to do.

After making these changes, use make to compile.

Note that you don't need to implement the RPC, language bindings, manual pages or anything else. It's all automatically generated from the OCaml description.

ADDING TESTS FOR AN API ACTION

You can supply zero or as many tests as you want per API call. The tests can either be added as part of the API description (generator/actions.ml), or in some rarer cases you may want to drop a script into tests/*/. Note that adding a script to tests/*/ is slower, so if possible use the first method.

The following describes the test environment used when you add an API test in actions.ml.

The test environment has 4 block devices:

/dev/sda 500MB

General block device for testing.

/dev/sdb 50MB

/dev/sdb1 is an ext2 filesystem used for testing filesystem write operations.

/dev/sdc 10MB

Used in a few tests where two block devices are needed.

/dev/sdd

ISO with fixed content (see images/test.iso).

To be able to run the tests in a reasonable amount of time, the libguestfs appliance and block devices are reused between tests. So don't try testing "guestfs_kill_subprocess" :-x

Each test starts with an initial scenario, selected using one of the Init* expressions, described in generator/types.ml. These initialize the disks mentioned above in a particular way as documented in types.ml. You should not assume anything about the previous contents of other disks that are not initialized.

You can add a prerequisite clause to any individual test. This is a run-time check, which, if it fails, causes the test to be skipped. Useful if testing a command which might not work on all variations of libguestfs builds. A test that has prerequisite of Always means to run unconditionally.

In addition, packagers can skip individual tests by setting environment variables before running make check.

 SKIP_TEST_<CMD>_<NUM>=1

eg: SKIP_TEST_COMMAND_3=1 skips test #3 of "guestfs_command".

or:

 SKIP_TEST_<CMD>=1

eg: SKIP_TEST_ZEROFREE=1 skips all "guestfs_zerofree" tests.

Packagers can run only certain tests by setting for example:

 TEST_ONLY="vfs_type zerofree"

See tests/c-api/tests.c for more details of how these environment variables work.

DEBUGGING NEW API ACTIONS

Test new actions work before submitting them.

You can use guestfish to try out new commands.

Debugging the daemon is a problem because it runs inside a minimal environment. However you can fprintf messages in the daemon to stderr, and they will show up if you use guestfish -v.

ADDING A NEW LANGUAGE BINDING

All language bindings must be generated by the generator (see the generator subdirectory).

There is no documentation for this yet. We suggest you look at an existing binding, eg. generator/ocaml.ml or generator/perl.ml.

ADDING TESTS FOR LANGUAGE BINDINGS

Language bindings should come with tests. Previously testing of language bindings was rather ad-hoc, but we have been trying to formalize the set of tests that every language binding should use.

Currently only the OCaml and Perl bindings actually implement the full set of tests, and the OCaml bindings are canonical, so you should emulate what the OCaml tests do.

This is the numbering scheme used by the tests:

 - 000+ basic tests:
 
   010  load the library
   020  create
   030  create-flags
   040  create multiple handles
   050  test setting and getting config properties
   060  explicit close
   070  optargs
 
 - 100  launch, create partitions and LVs and filesystems
 
 - 400+ events:
 
   410  close event
   420  log messages
   430  progress messages
 
 - 800+ regression tests (specific to the language)
 
 - 900+ any other custom tests for the language

To save time when running the tests, only 100, 430, 800+, 900+ should launch the handle.

FORMATTING CODE

Our C source code generally adheres to some basic code-formatting conventions. The existing code base is not totally consistent on this front, but we do prefer that contributed code be formatted similarly. In short, use spaces-not-TABs for indentation, use 2 spaces for each indentation level, and other than that, follow the K&R style.

If you use Emacs, add the following to one of one of your start-up files (e.g., ~/.emacs), to help ensure that you get indentation right:

 ;;; In libguestfs, indent with spaces everywhere (not TABs).
 ;;; Exceptions: Makefile and ChangeLog modes.
 (add-hook 'find-file-hook
     '(lambda () (if (and buffer-file-name
                          (string-match "/libguestfs\\>"
                              (buffer-file-name))
                          (not (string-equal mode-name "Change Log"))
                          (not (string-equal mode-name "Makefile")))
                     (setq indent-tabs-mode nil))))
 
 ;;; When editing C sources in libguestfs, use this style.
 (defun libguestfs-c-mode ()
   "C mode with adjusted defaults for use with libguestfs."
   (interactive)
   (c-set-style "K&R")
   (setq c-indent-level 2)
   (setq c-basic-offset 2))
 (add-hook 'c-mode-hook
           '(lambda () (if (string-match "/libguestfs\\>"
                               (buffer-file-name))
                           (libguestfs-c-mode))))

TESTING YOUR CHANGES

Enable warnings when compiling (and fix any problems this finds):

 ./configure --enable-gcc-warnings

Useful targets are:

make check

Runs the regular test suite.

This is implemented using the regular automake TESTS target. See the automake documentation for details.

make syntax-check -j1 -k

Checks for various syntax and style problems in the code.

make check-valgrind

Runs a subset of the test suite under valgrind.

Any Makefile.am in the tree that has a check-valgrind: target will be run by this rule.

make check-valgrind-local-guests

Runs a subset of the test suite under valgrind using locally installed libvirt guests (read-only).

make check-direct

Runs all tests using default appliance back-end. This only has any effect if a non-default backend was selected using ./configure --with-default-backend=...

make check-valgrind-direct

Run a subset of the test suite under valgrind using the default appliance back-end.

make check-uml

Runs all tests using the User-Mode Linux backend.

As there is no standard location for the User-Mode Linux kernel, you have to set LIBGUESTFS_HV to point to the kernel image, eg:

 make check-uml LIBGUESTFS_HV=~/d/linux-um/vmlinux
make check-valgrind-uml

Runs all tests using the User-Mode Linux backend, under valgrind.

As above, you have to set LIBGUESTFS_HV to point to the kernel.

make check-with-upstream-qemu

Runs all tests using a local qemu binary. It looks for the qemu binary in QEMUDIR (defaults to $HOME/d/qemu), but you can set this to another directory on the command line, eg:

 make check-with-upstream-qemu QEMUDIR=/usr/src/qemu
make check-with-upstream-libvirt

Runs all tests using a local libvirt. This only has any effect if the libvirt backend was selected using ./configure --with-default-backend=libvirt

It looks for libvirt in LIBVIRTDIR (defaults to $HOME/d/libvirt), but you can set this to another directory on the command line, eg:

 make check-with-upstream-libvirt LIBVIRTDIR=/usr/src/libvirt
make check-slow

Runs some slow/long-running tests which are not run by default.

Any Makefile.am in the tree that has a check-slow: target will be run by this rule.

make check-all

Equivalent to running all make check* rules.

make check-release

Runs a subset of make check* rules that are required to pass before a tarball can be released. Currently this is:

DAEMON CUSTOM PRINTF FORMATTERS

In the daemon code we have created custom printf formatters %Q and %R, which are used to do shell quoting.

%Q

Simple shell quoted string. Any spaces or other shell characters are escaped for you.

%R

Same as %Q except the string is treated as a path which is prefixed by the sysroot.

For example:

 asprintf (&cmd, "cat %R", path);

would produce cat /sysroot/some\ path\ with\ spaces

Note: Do not use these when you are passing parameters to the command{,r,v,rv}() functions. These parameters do NOT need to be quoted because they are not passed via the shell (instead, straight to exec). You probably want to use the sysroot_path() function however.

SUBMITTING YOUR NEW API ACTIONS

Submit patches to the mailing list: http://www.redhat.com/mailman/listinfo/libguestfs and CC to rjones@redhat.com.

INTERNATIONALIZATION (I18N) SUPPORT

We support i18n (gettext anyhow) in the library.

However many messages come from the daemon, and we don't translate those at the moment. One reason is that the appliance generally has all locale files removed from it, because they take up a lot of space. So we'd have to readd some of those, as well as copying our PO files into the appliance.

Debugging messages are never translated, since they are intended for the programmers.

SOURCE CODE SUBDIRECTORIES

align

virt-alignment-scan(1) command and documentation.

appliance

The libguestfs appliance, build scripts and so on.

bash

Bash tab-completion scripts.

build-aux

Various build scripts used by autotools.

builder

virt-builder(1) command and documentation.

cat

The virt-cat(1), virt-filesystems(1) and virt-ls(1) commands and documentation.

contrib

Outside contributions, experimental parts.

customize

virt-customize(1) command and documentation.

daemon

The daemon that runs inside the libguestfs appliance and carries out actions.

df

virt-df(1) command and documentation.

diff

virt-diff(1) command and documentation.

edit

virt-edit(1) command and documentation.

examples

C API example code.

fish

guestfish(1), the command-line shell, and various shell scripts built on top such as virt-copy-in(1), virt-copy-out(1), virt-tar-in(1), virt-tar-out(1).

format

virt-format(1) command and documentation.

fuse

guestmount(1), FUSE (userspace filesystem) built on top of libguestfs.

generator

The crucially important generator, used to automatically generate large amounts of boilerplate C code for things like RPC and bindings.

gnulib

Gnulib is used as a portability library. A copy of gnulib is included under here.

html

Generated HTML manual pages.

inspector

virt-inspector(1), the virtual machine image inspector.

logo

Logo used on the website. The fish is called Arthur by the way.

m4

M4 macros used by autoconf.

make-fs

virt-make-fs(1) command and documentation.

mllib

Various libraries and common code used by virt-resize(1) and the other tools which are written in OCaml.

po

Translations of simple gettext strings.

po-docs

The build infrastructure and PO files for translations of manpages and POD files. Eventually this will be combined with the po directory, but that is rather complicated.

rescue

virt-rescue(1) command and documentation.

resize

virt-resize(1) command and documentation.

sparsify

virt-sparsify(1) command and documentation.

src

Source code to the C library.

sysprep

virt-sysprep(1) command and documentation.

tests

Tests.

test-tool

Test tool for end users to test if their qemu/kernel combination will work with libguestfs.

tmp

Used for temporary files when running the tests (instead of /tmp etc). The reason is so that you can run multiple parallel tests of libguestfs without having one set of tests overwriting the appliance created by another.

tools

Command line tools written in Perl (virt-win-reg(1) and many others).

csharp
erlang
gobject
golang
haskell
java
lua
ocaml
php
perl
python
ruby

Language bindings.

MAKING A STABLE RELEASE

When we make a stable release, there are several steps documented here. See "LIBGUESTFS VERSION NUMBERS" for general information about the stable branch policy.

LIMITS

PROTOCOL LIMITS

Internally libguestfs uses a message-based protocol to pass API calls and their responses to and from a small "appliance" (see "INTERNALS" for plenty more detail about this). The maximum message size used by the protocol is slightly less than 4 MB. For some API calls you may need to be aware of this limit. The API calls which may be affected are individually documented, with a link back to this section of the documentation.

In libguestfs < 1.19.32, several calls had to encode either their entire argument list or their entire return value (or sometimes both) in a single protocol message, and this gave them an arbitrary limitation on how much data they could handle. For example, "guestfs_cat" could only download a file if it was less than around 4 MB in size. In later versions of libguestfs, some of these limits have been removed. The APIs which were previously limited but are now unlimited (except perhaps by available memory) are listed below. To find out if a specific API is subject to protocol limits, check for the warning in the API documentation which links to this section, and remember to check the version of the documentation that matches the version of libguestfs you are using.

"guestfs_cat", "guestfs_find", "guestfs_read_file", "guestfs_read_lines", "guestfs_write", "guestfs_write_append", "guestfs_lstatlist", "guestfs_lxattrlist", "guestfs_readlinklist", "guestfs_ls".

See also "UPLOADING" and "DOWNLOADING" for further information about copying large amounts of data into or out of a filesystem.

MAXIMUM NUMBER OF DISKS

In libguestfs ≥ 1.19.7, you can query the maximum number of disks that may be added by calling "guestfs_max_disks". In earlier versions of libguestfs (ie. where this call is not available) you should assume the maximum is 25.

The rest of this section covers implementation details, which could change in future.

When using virtio-scsi disks (the default if available in qemu) the current limit is 255 disks. When using virtio-blk (the old default) the limit is around 27 disks, but may vary according to implementation details and whether the network is enabled.

Virtio-scsi as used by libguestfs is configured to use one target per disk, and 256 targets are available.

Virtio-blk consumes 1 virtual PCI slot per disk, and PCI is limited to 31 slots, but some of these are used for other purposes.

One virtual disk is used by libguestfs internally.

Before libguestfs 1.19.7, disk names had to be a single character (eg. /dev/sda through /dev/sdz), and since one disk is reserved, that meant the limit was 25. This has been fixed in more recent versions.

In libguestfs ≥ 1.20 it is possible to hot plug disks. See "HOTPLUGGING".

MAXIMUM NUMBER OF PARTITIONS PER DISK

Virtio limits the maximum number of partitions per disk to 15.

This is because it reserves 4 bits for the minor device number (thus /dev/vda, and /dev/vda1 through /dev/vda15).

If you attach a disk with more than 15 partitions, the extra partitions are ignored by libguestfs.

MAXIMUM SIZE OF A DISK

Probably the limit is between 2**63-1 and 2**64-1 bytes.

We have tested block devices up to 1 exabyte (2**60 or 1,152,921,504,606,846,976 bytes) using sparse files backed by an XFS host filesystem.

Although libguestfs probably does not impose any limit, the underlying host storage will. If you store disk images on a host ext4 filesystem, then the maximum size will be limited by the maximum ext4 file size (currently 16 TB). If you store disk images as host logical volumes then you are limited by the maximum size of an LV.

For the hugest disk image files, we recommend using XFS on the host for storage.

MAXIMUM SIZE OF A PARTITION

The MBR (ie. classic MS-DOS) partitioning scheme uses 32 bit sector numbers. Assuming a 512 byte sector size, this means that MBR cannot address a partition located beyond 2 TB on the disk.

It is recommended that you use GPT partitions on disks which are larger than this size. GPT uses 64 bit sector numbers and so can address partitions which are theoretically larger than the largest disk we could support.

MAXIMUM SIZE OF A FILESYSTEM, FILES, DIRECTORIES

This depends on the filesystem type. libguestfs itself does not impose any known limit. Consult Wikipedia or the filesystem documentation to find out what these limits are.

MAXIMUM UPLOAD AND DOWNLOAD

The API functions "guestfs_upload", "guestfs_download", "guestfs_tar_in", "guestfs_tar_out" and the like allow unlimited sized uploads and downloads.

INSPECTION LIMITS

The inspection code has several arbitrary limits on things like the size of Windows Registry hive it will read, and the length of product name. These are intended to stop a malicious guest from consuming arbitrary amounts of memory and disk space on the host, and should not be reached in practice. See the source code for more information.

ENVIRONMENT VARIABLES

FEBOOTSTRAP_KERNEL
FEBOOTSTRAP_MODULES

When using supermin ≥ 4.1.0, these have been renamed "SUPERMIN_KERNEL" and "SUPERMIN_MODULES".

LIBGUESTFS_APPEND

Pass additional options to the guest kernel.

LIBGUESTFS_ATTACH_METHOD

This is the old way to set LIBGUESTFS_BACKEND.

LIBGUESTFS_BACKEND

Choose the default way to create the appliance. See "guestfs_set_backend" and "BACKEND".

LIBGUESTFS_BACKEND_SETTINGS

A colon-separated list of backend-specific settings. See "BACKEND", "BACKEND SETTINGS".

LIBGUESTFS_CACHEDIR

The location where libguestfs will cache its appliance, when using a supermin appliance. The appliance is cached and shared between all handles which have the same effective user ID.

If LIBGUESTFS_CACHEDIR is not set, then TMPDIR is used. If TMPDIR is not set, then /var/tmp is used.

See also "LIBGUESTFS_TMPDIR", "guestfs_set_cachedir".

LIBGUESTFS_DEBUG

Set LIBGUESTFS_DEBUG=1 to enable verbose messages. This has the same effect as calling guestfs_set_verbose (g, 1).

LIBGUESTFS_HV

Set the default hypervisor (usually qemu) binary that libguestfs uses. If not set, then the qemu which was found at compile time by the configure script is used.

See also "QEMU WRAPPERS" above.

LIBGUESTFS_MEMSIZE

Set the memory allocated to the qemu process, in megabytes. For example:

 LIBGUESTFS_MEMSIZE=700
LIBGUESTFS_PATH

Set the path that libguestfs uses to search for a supermin appliance. See the discussion of paths in section "PATH" above.

LIBGUESTFS_QEMU

This is the old way to set LIBGUESTFS_HV.

LIBGUESTFS_TMPDIR

The location where libguestfs will store temporary files used by each handle.

If LIBGUESTFS_TMPDIR is not set, then TMPDIR is used. If TMPDIR is not set, then /tmp is used.

See also "LIBGUESTFS_CACHEDIR", "guestfs_set_tmpdir".

LIBGUESTFS_TRACE

Set LIBGUESTFS_TRACE=1 to enable command traces. This has the same effect as calling guestfs_set_trace (g, 1).

PATH

Libguestfs may run some external programs, and relies on $PATH being set to a reasonable value. If using the libvirt backend, libvirt will not work at all unless $PATH contains the path of qemu/KVM. Note that PHP by default removes $PATH from the environment which tends to break everything.

SUPERMIN_KERNEL
SUPERMIN_MODULES

These two environment variables allow the kernel that libguestfs uses in the appliance to be selected. If $SUPERMIN_KERNEL is not set, then the most recent host kernel is chosen. For more information about kernel selection, see supermin(1). This feature is only available in supermin / febootstrap ≥ 3.8.

TMPDIR

See "LIBGUESTFS_CACHEDIR", "LIBGUESTFS_TMPDIR".

SEE ALSO

guestfs-examples(3), guestfs-erlang(3), guestfs-golang(3), guestfs-java(3), guestfs-lua(3), guestfs-ocaml(3), guestfs-perl(3), guestfs-python(3), guestfs-ruby(3), guestfish(1), guestmount(1), virt-alignment-scan(1), virt-builder(1), virt-cat(1), virt-copy-in(1), virt-copy-out(1), virt-customize(1), virt-df(1), virt-diff(1), virt-edit(1), virt-filesystems(1), virt-format(1), virt-inspector(1), virt-list-filesystems(1), virt-list-partitions(1), virt-ls(1), virt-make-fs(1), virt-rescue(1), virt-resize(1), virt-sparsify(1), virt-sysprep(1), virt-tar(1), virt-tar-in(1), virt-tar-out(1), virt-win-reg(1), guestfs-faq(1), guestfs-performance(1), guestfs-release-notes(1), guestfs-testing(1), libguestfs-test-tool(1), libguestfs-make-fixed-appliance(1), supermin(1), qemu(1), hivex(3), stap(1), sd-journal(3), http://libguestfs.org/.

Tools with a similar purpose: fdisk(8), parted(8), kpartx(8), lvm(8), disktype(1).

AUTHORS

Richard W.M. Jones (rjones at redhat dot com)

COPYRIGHT

Copyright (C) 2009-2014 Red Hat Inc.

LICENSE

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

BUGS

To get a list of bugs against libguestfs, use this link: https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools

To report a new bug against libguestfs, use this link: https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools

When reporting a bug, please supply: