NAME¶

Sys::Guestfs - Perl bindings for libguestfs

SYNOPSIS¶

 use Sys::Guestfs;
 my $h = Sys::Guestfs->new ();
 $h->add_drive_opts ('guest.img', format => 'raw');
 $h->launch ();
 $h->mount_options ('', '/dev/sda1', '/');
 $h->touch ('/hello');
 $h->sync ();

DESCRIPTION¶

The "Sys::Guestfs" module provides a Perl XS binding to the libguestfs API for examining and modifying virtual machine disk images. Amongst the things this is good for: making batch configuration changes to guests, getting disk used/free statistics (see also: virt-df), migrating between virtualization systems (see also: virt-p2v), performing partial backups, performing partial guest clones, cloning guests and changing registry/UUID/hostname info, and much else besides. Libguestfs uses Linux kernel and qemu code, and can access any type of guest filesystem that Linux and qemu can, including but not limited to: ext2/3/4, btrfs, FAT and NTFS, LVM, many different disk partition schemes, qcow, qcow2, vmdk. Libguestfs provides ways to enumerate guest storage (eg. partitions, LVs, what filesystem is in each LV, etc.). It can also run commands in the context of the guest. Also you can access filesystems over FUSE. See also Sys::Guestfs::Lib(3) for a set of useful library functions for using libguestfs from Perl, including integration with libvirt.

ERRORS¶

All errors turn into calls to "croak" (see Carp(3)). The error string from libguestfs is directly available from $@. Use the "last_errno" method if you want to get the errno.

METHODS¶

$h = Sys::Guestfs->new ();

Create a new guestfs handle.

$h->close ();

Explicitly close the guestfs handle.

 

Note: You should not usually call this function. The handle will be closed implicitly when its reference count goes to zero (eg. when it goes out of scope or the program ends). This call is only required in some exceptional cases, such as where the program may contain cached references to the handle 'somewhere' and you really have to have the close happen right away. After calling "close" the program must not call any method (including "close") on the handle (but the implicit call to "DESTROY" that happens when the final reference is cleaned up is OK).

$Sys::Guestfs::EVENT_CLOSE

See "GUESTFS_EVENT_CLOSE" in guestfs(3).

$Sys::Guestfs::EVENT_SUBPROCESS_QUIT

See "GUESTFS_EVENT_SUBPROCESS_QUIT" in guestfs(3).

$Sys::Guestfs::EVENT_LAUNCH_DONE

See "GUESTFS_EVENT_LAUNCH_DONE" in guestfs(3).

$Sys::Guestfs::EVENT_PROGRESS

See "GUESTFS_EVENT_PROGRESS" in guestfs(3).

$Sys::Guestfs::EVENT_APPLIANCE

See "GUESTFS_EVENT_APPLIANCE" in guestfs(3).

$Sys::Guestfs::EVENT_LIBRARY

See "GUESTFS_EVENT_LIBRARY" in guestfs(3).

$Sys::Guestfs::EVENT_TRACE

See "GUESTFS_EVENT_TRACE" in guestfs(3).

$Sys::Guestfs::EVENT_ENTER

See "GUESTFS_EVENT_ENTER" in guestfs(3).

$event_handle = $h->set_event_callback (\&cb, $event_bitmask);

Register "cb" as a callback function for all of the events in $event_bitmask (one or more "$Sys::Guestfs::EVENT_*" flags logically or'd together).

 

This function returns an event handle which can be used to delete the callback using "delete_event_callback".

 

The callback function receives 4 parameters:

 

 &cb ($event, $event_handle, $buf, $array)
    

$h->delete_event_callback ($event_handle);

This removes the callback which was previously registered using "set_event_callback".

$errnum = $h->last_errno ();

This returns the last error number (errno) that happened on the handle $h.

 

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

 

If no error number is available, this returns 0. See "guestfs_last_errno" in guestfs(3) for more details of why this can happen.

 

You can use the standard Perl module Errno(3) to compare the numeric error returned from this call with symbolic errnos:

 

 $h->mkdir ("/foo");
 if ($h->last_errno() == Errno::EEXIST()) {
   # mkdir failed because the directory exists already.
 }
    

$h->user_cancel ();

Cancel current transfer. This is safe to call from Perl signal handlers and threads.

$h->add_cdrom ($filename);

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

 

This is equivalent to the qemu parameter -cdrom filename.

 

Notes:

$nrdisks = $h->add_domain ($dom [, libvirturi => $libvirturi] [, readonly => $readonly] [, iface => $iface] [, live => $live] [, allowuuid => $allowuuid] [, readonlydisk => $readonlydisk]);

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 "$h->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:

$h->add_drive ($filename);

This function is the equivalent of calling "$h->add_drive_opts" with no optional parameters, so the disk is added writable, with the format being detected automatically.

 

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. Therefore you should think about replacing calls to this function with calls to "$h->add_drive_opts", and specifying the format.

$h->add_drive_opts ($filename [, readonly => $readonly] [, format => $format] [, iface => $iface] [, name => $name]);

This function adds a virtual machine disk image "filename" to libguestfs. The first time you call this function, the disk appears as "/dev/sda", the second time as "/dev/sdb", and so on.

 

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.

 

The optional arguments are:

$h->add_drive_ro ($filename);

This function is the equivalent of calling "$h->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.

$h->add_drive_ro_with_if ($filename, $iface);

This is the same as "$h->add_drive_ro" but it allows you to specify the QEMU interface emulation to use at run time.

 

This function is deprecated. In new code, use the "add_drive_opts" 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.

$h->add_drive_with_if ($filename, $iface);

This is the same as "$h->add_drive" but it allows you to specify the QEMU interface emulation to use at run time.

 

This function is deprecated. In new code, use the "add_drive_opts" 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.

$h->aug_clear ($augpath);

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

$h->aug_close ();

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

%nrnodescreated = $h->aug_defnode ($name, $expr, $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 "$h->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.

$nrnodes = $h->aug_defvar ($name, $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.

$val = $h->aug_get ($augpath);

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

$h->aug_init ($root, $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 "$h->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:

$h->aug_insert ($augpath, $label, $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]".

$h->aug_load ();

Load files into the tree.

 

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

@matches = $h->aug_ls ($augpath);

This is just a shortcut for listing "$h->aug_match" "path/*" and sorting the resulting nodes into alphabetical order.

@matches = $h->aug_match ($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.

$h->aug_mv ($src, $dest);

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

$nrnodes = $h->aug_rm ($augpath);

Remove "path" and all of its children.

 

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

$h->aug_save ();

This writes all pending changes to disk.

 

The flags which were passed to "$h->aug_init" affect exactly how files are saved.

$h->aug_set ($augpath, $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 "$h->aug_clear" call.

$h->available (\@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 "$h->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:

@groups = $h->available_all_groups ();

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 "$h->available" on each member of the returned list.

 

See also "$h->available" and "AVAILABILITY" in guestfs(3).

$h->base64_in ($base64file, $filename);

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

$h->base64_out ($filename, $base64file);

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

%info = $h->blkid ($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.

$h->blockdev_flushbufs ($device);

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

 

This uses the blockdev(8) command.

$blocksize = $h->blockdev_getbsz ($device);

This returns the block size of a device.

 

(Note this is different from both size in blocks and filesystem block size).

 

This uses the blockdev(8) command.

$ro = $h->blockdev_getro ($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.

$sizeinbytes = $h->blockdev_getsize64 ($device);

This returns the size of the device in bytes.

 

See also "$h->blockdev_getsz".

 

This uses the blockdev(8) command.

$sectorsize = $h->blockdev_getss ($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 "$h->blockdev_getsz" for that).

 

This uses the blockdev(8) command.

$sizeinsectors = $h->blockdev_getsz ($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 "$h->blockdev_getss" for the real sector size of the device, and "$h->blockdev_getsize64" for the more useful size in bytes.

 

This uses the blockdev(8) command.

$h->blockdev_rereadpt ($device);

Reread the partition table on "device".

 

This uses the blockdev(8) command.

$h->blockdev_setbsz ($device, $blocksize);

This sets the block size of a device.

 

(Note this is different from both size in blocks and filesystem block size).

 

This uses the blockdev(8) command.

$h->blockdev_setro ($device);

Sets the block device named "device" to read-only.

 

This uses the blockdev(8) command.

$h->blockdev_setrw ($device);

Sets the block device named "device" to read-write.

 

This uses the blockdev(8) command.

$h->btrfs_device_add (\@devices, $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.

$h->btrfs_device_delete (\@devices, $fs);

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

$h->btrfs_filesystem_balance ($fs);

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

$h->btrfs_filesystem_resize ($mountpoint [, size => $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:

$h->btrfs_filesystem_sync ($fs);

Force sync on the btrfs filesystem mounted at "fs".

$h->btrfs_fsck ($device [, superblock => $superblock] [, repair => $repair]);

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

$h->btrfs_set_seeding ($device, $seeding);

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

$h->btrfs_subvolume_create ($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".

$h->btrfs_subvolume_delete ($subvolume);

Delete the named btrfs subvolume.

@subvolumes = $h->btrfs_subvolume_list ($fs);

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

$h->btrfs_subvolume_set_default ($id, $fs);

Set the subvolume of the btrfs filesystem "fs" which will be mounted by default. See "$h->btrfs_subvolume_list" to get a list of subvolumes.

$h->btrfs_subvolume_snapshot ($source, $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".

$rpath = $h->case_sensitive_path ($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 <http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1>

 

This function resolves the true case of each element in the path and returns the case-sensitive path.

 

Thus "$h->case_sensitive_path" ("/Windows/System32") might return "/WINDOWS/system32" (the exact return value would depend on details of how the directories were originally created under Windows).

 

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

 

See also "$h->realpath".

$content = $h->cat ($path);

Return the contents of the file named "path".

 

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 "$h->read_file" or "$h->download" functions which have a more complex interface.

 

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

$checksum = $h->checksum ($csumtype, $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:

$checksum = $h->checksum_device ($csumtype, $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 "$h->checksum" command.

$h->checksums_out ($csumtype, $directory, $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.

$h->chmod ($mode, $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.

$h->chown ($owner, $group, $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).

$output = $h->command (\@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 "$h->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.

 

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

@lines = $h->command_lines (\@arguments);

This is the same as "$h->command", but splits the result into a list of lines.

 

See also: "$h->sh_lines"

 

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

$h->compress_device_out ($ctype, $device, $zdevice [, level => $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 "$h->compress_out".

$h->compress_out ($ctype, $file, $zfile [, level => $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.

$h->config ($qemuparam, $qemuvalue);

This can be used to add arbitrary qemu command line 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 "param" string must be a "-" (dash).

 

"value" can be NULL.

$h->copy_device_to_device ($src, $dest [, srcoffset => $srcoffset] [, destoffset => $destoffset] [, size => $size]);

The four calls "$h->copy_device_to_device", "$h->copy_device_to_file", "$h->copy_file_to_device", and "$h->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.

$h->copy_device_to_file ($src, $dest [, srcoffset => $srcoffset] [, destoffset => $destoffset] [, size => $size]);

See "$h->copy_device_to_device" for a general overview of this call.

$h->copy_file_to_device ($src, $dest [, srcoffset => $srcoffset] [, destoffset => $destoffset] [, size => $size]);

See "$h->copy_device_to_device" for a general overview of this call.

$h->copy_file_to_file ($src, $dest [, srcoffset => $srcoffset] [, destoffset => $destoffset] [, size => $size]);

See "$h->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 "$h->cp", "$h->cp_a" and "$h->mv" for general file copying and moving functions.

$h->copy_size ($src, $dest, $size);

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 is deprecated. In new code, use the "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.

$h->cp ($src, $dest);

This copies a file from "src" to "dest" where "dest" is either a destination filename or destination directory.

$h->cp_a ($src, $dest);

This copies a file or directory from "src" to "dest" recursively using the "cp -a" command.

$h->dd ($src, $dest);

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 "$h->copy_device_to_device").

 

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

$output = $h->df ();

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 "$h->statvfs" from programs.

$output = $h->df_h ();

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 "$h->statvfs" from programs.

$kmsgs = $h->dmesg ();

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 "$h->set_verbose" or by setting the environment variable "LIBGUESTFS_DEBUG=1" before running the program.

$h->download ($remotefilename, $filename);

Download file "remotefilename" and save it as "filename" on the local machine.

 

"filename" can also be a named pipe.

 

See also "$h->upload", "$h->cat".

$h->download_offset ($remotefilename, $filename, $offset, $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 "$h->pread", and this call always reads the full amount unless an error occurs.

 

See also "$h->download", "$h->pread".

$h->drop_caches ($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 <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.

$sizekb = $h->du ($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).

$h->e2fsck ($device [, correct => $correct] [, forceall => $forceall]);

This runs the ext2/ext3 filesystem checker on "device". It can take the following optional arguments:

$h->e2fsck_f ($device);

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 is deprecated. In new code, use the "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.

$output = $h->echo_daemon (\@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 "$h->ping_daemon".

@lines = $h->egrep ($regex, $path);

This calls the external "egrep" program and returns the matching lines.

 

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

@lines = $h->egrepi ($regex, $path);

This calls the external "egrep -i" program and returns the matching lines.

 

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

$equality = $h->equal ($file1, $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.

$existsflag = $h->exists ($path);

This returns "true" if and only if there is a file, directory (or anything) with the given "path" name.

 

See also "$h->is_file", "$h->is_dir", "$h->stat".

$h->fallocate ($path, $len);

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 is deprecated. In new code, use the "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.

$h->fallocate64 ($path, $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 "$h->truncate_size" instead.

 

The deprecated call "$h->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.

@lines = $h->fgrep ($pattern, $path);

This calls the external "fgrep" program and returns the matching lines.

 

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

@lines = $h->fgrepi ($pattern, $path);

This calls the external "fgrep -i" program and returns the matching lines.

 

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

$description = $h->file ($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), "$h->vfs_type", "$h->lstat", "$h->is_file", "$h->is_blockdev" (etc), "$h->is_zero".

$arch = $h->file_architecture ($filename);

This detects the architecture of the binary "filename", and returns it if known.

 

Currently defined architectures are:

$size = $h->filesize ($file);

This command returns the size of "file" in bytes.

 

To get other stats about a file, use "$h->stat", "$h->lstat", "$h->is_dir", "$h->is_file" etc. To get the size of block devices, use "$h->blockdev_getsize64".

$h->fill ($c, $len, $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 "$h->truncate_size". To create a file with a pattern of repeating bytes use "$h->fill_pattern".

$h->fill_pattern ($pattern, $len, $path);

This function is like "$h->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.

@names = $h->find ($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 "$h->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.

 

See also "$h->find0".

 

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

$h->find0 ($directory, $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 "$h->find" with the following exceptions:

$device = $h->findfs_label ($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 "$h->vfs_label".

$device = $h->findfs_uuid ($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 "$h->vfs_uuid".

$status = $h->fsck ($fstype, $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:

$append = $h->get_append ();

Return the additional kernel options which are added to the guest kernel command line.

 

If "NULL" then no options are added.

$attachmethod = $h->get_attach_method ();

Return the current attach method. See "$h->set_attach_method".

$autosync = $h->get_autosync ();

Get the autosync flag.

$direct = $h->get_direct ();

Return the direct appliance mode flag.

$attrs = $h->get_e2attrs ($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:

$generation = $h->get_e2generation ($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 "$h->set_e2generation".

$label = $h->get_e2label ($device);

This returns the ext2/3/4 filesystem label of the filesystem on "device".

 

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

$uuid = $h->get_e2uuid ($device);

This returns the ext2/3/4 filesystem UUID of the filesystem on "device".

 

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

$memsize = $h->get_memsize ();

This gets the memory size in megabytes allocated to the qemu subprocess.

 

If "$h->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).

$network = $h->get_network ();

This returns the enable network flag.

$path = $h->get_path ();

Return the current search path.

 

This is always non-NULL. If it wasn't set already, then this will return the default path.

$pgroup = $h->get_pgroup ();

This returns the process group flag.

$pid = $h->get_pid ();

Return the process ID of the qemu subprocess. If there is no qemu subprocess, then this will return an error.

 

This is an internal call used for debugging and testing.

$qemu = $h->get_qemu ();

Return the current qemu binary.

 

This is always non-NULL. If it wasn't set already, then this will return the default qemu binary name.

$recoveryproc = $h->get_recovery_proc ();

Return the recovery process enabled flag.

$selinux = $h->get_selinux ();

This returns the current setting of the selinux flag which is passed to the appliance at boot time. See "$h->set_selinux".

 

For more information on the architecture of libguestfs, see guestfs(3).

$smp = $h->get_smp ();

This returns the number of virtual CPUs assigned to the appliance.

$state = $h->get_state ();

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).

$trace = $h->get_trace ();

Return the command trace flag.

$mask = $h->get_umask ();

Return the current umask. By default the umask is 022 unless it has been set by calling "$h->umask".

$verbose = $h->get_verbose ();

This returns the verbose messages flag.

$context = $h->getcon ();

This gets the SELinux security context of the daemon.

 

See the documentation about SELINUX in guestfs(3), and "$h->setcon"

$xattr = $h->getxattr ($path, $name);

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 "$h->lgetxattr".

 

Normally it is better to get all extended attributes from a file in one go by calling "$h->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: "$h->getxattrs", "$h->lgetxattr", attr(5).

@xattrs = $h->getxattrs ($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: "$h->lgetxattrs", attr(5).

@paths = $h->glob_expand ($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 "$h->list_devices", "$h->list_partitions" etc functions instead.

@lines = $h->grep ($regex, $path);

This calls the external "grep" program and returns the matching lines.

 

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

@lines = $h->grepi ($regex, $path);

This calls the external "grep -i" program and returns the matching lines.

 

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

$h->grub_install ($root, $device);

This command installs GRUB 1 (the Grand Unified Bootloader) on "device", with the root directory being "root".

 

Notes:

@lines = $h->head ($path);

This command returns up to the first 10 lines of a file as a list of strings.

 

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

@lines = $h->head_n ($nrlines, $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.

 

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

$dump = $h->hexdump ($path);

This runs "hexdump -C" on the given "path". The result is the human-readable, canonical hex dump of the file.

 

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

$content = $h->initrd_cat ($initrdpath, $filename);

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 "$h->initrd_list".

 

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

@filenames = $h->initrd_list ($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).

$wd = $h->inotify_add_watch ($path, $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".

$h->inotify_close ();

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.

@paths = $h->inotify_files ();

This function is a helpful wrapper around "$h->inotify_read" which just returns a list of pathnames of objects that were touched. The returned pathnames are sorted and deduplicated.

$h->inotify_init ($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 "$h->inotify_read" or "$h->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 "$h->inotify_read").

 

Before any events are generated, you have to add some watches to the internal watch list. See: "$h->inotify_add_watch" and "$h->inotify_rm_watch".

 

Queued up events should be read periodically by calling "$h->inotify_read" (or "$h->inotify_files" which is just a helpful wrapper around "$h->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 "$h->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.

@events = $h->inotify_read ();

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.

$h->inotify_rm_watch ($wd);

Remove a previously defined inotify watch. See "$h->inotify_add_watch".

$arch = $h->inspect_get_arch ($root);

This returns the architecture of the inspected operating system. The possible return values are listed under "$h->file_architecture".

 

If the architecture could not be determined, then the string "unknown" is returned.

 

Please read "INSPECTION" in guestfs(3) for more details.

$distro = $h->inspect_get_distro ($root);

This returns the distro (distribution) of the inspected operating system.

 

Currently defined distros are:

%drives = $h->inspect_get_drive_mappings ($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 "$h->inspect_get_mountpoints", "$h->inspect_get_filesystems".

@filesystems = $h->inspect_get_filesystems ($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 "$h->inspect_get_mountpoints".

$format = $h->inspect_get_format ($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:

$hostname = $h->inspect_get_hostname ($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.

$icon = $h->inspect_get_icon ($root [, favicon => $favicon] [, highquality => $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:

$major = $h->inspect_get_major_version ($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.

$minor = $h->inspect_get_minor_version ($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 "$h->inspect_get_major_version".

%mountpoints = $h->inspect_get_mountpoints ($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 "$h->inspect_get_drive_mappings".

 

Please read "INSPECTION" in guestfs(3) for more details. See also "$h->inspect_get_filesystems".

$packageformat = $h->inspect_get_package_format ($root);

This function and "$h->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.

$packagemanagement = $h->inspect_get_package_management ($root);

"$h->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.

$product = $h->inspect_get_product_name ($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.

$variant = $h->inspect_get_product_variant ($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 "$h->inspect_get_product_name", "$h->inspect_get_major_version".

@roots = $h->inspect_get_roots ();

This function is a convenient way to get the list of root devices, as returned from a previous call to "$h->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 "$h->inspect_os".

 

Please read "INSPECTION" in guestfs(3) for more details.

$name = $h->inspect_get_type ($root);

This returns the type of the inspected operating system. Currently defined types are:

$controlset = $h->inspect_get_windows_current_control_set ($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.

$systemroot = $h->inspect_get_windows_systemroot ($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.

$live = $h->inspect_is_live ($root);

If "$h->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.

$multipart = $h->inspect_is_multipart ($root);

If "$h->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.

$netinst = $h->inspect_is_netinst ($root);

If "$h->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.

@applications = $h->inspect_list_applications ($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 "$h->inspect_os", then "$h->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 "$h->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:

@roots = $h->inspect_os ();

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 "$h->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 "$h->mount_ro" and "$h->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 "$h->list_filesystems".

$flag = $h->is_blockdev ($path);

This returns "true" if and only if there is a block device with the given "path" name.

 

See also "$h->stat".

$flag = $h->is_chardev ($path);

This returns "true" if and only if there is a character device with the given "path" name.

 

See also "$h->stat".

$config = $h->is_config ();

This returns true iff this handle is being configured (in the "CONFIG" state).

 

For more information on states, see guestfs(3).

$dirflag = $h->is_dir ($path);

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.

 

See also "$h->stat".

$flag = $h->is_fifo ($path);

This returns "true" if and only if there is a FIFO (named pipe) with the given "path" name.

 

See also "$h->stat".

$fileflag = $h->is_file ($path);

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.

 

See also "$h->stat".

$launching = $h->is_launching ();

This returns true iff this handle is launching the subprocess (in the "LAUNCHING" state).

 

For more information on states, see guestfs(3).

$lvflag = $h->is_lv ($device);

This command tests whether "device" is a logical volume, and returns true iff this is the case.

$ready = $h->is_ready ();

This returns true iff this handle is ready to accept commands (in the "READY" state).

 

For more information on states, see guestfs(3).

$flag = $h->is_socket ($path);

This returns "true" if and only if there is a Unix domain socket with the given "path" name.

 

See also "$h->stat".

$flag = $h->is_symlink ($path);

This returns "true" if and only if there is a symbolic link with the given "path" name.

 

See also "$h->stat".

$zeroflag = $h->is_zero ($path);

This returns true iff the file exists and the file is empty or it contains all zero bytes.

$zeroflag = $h->is_zero_device ($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.

%isodata = $h->isoinfo ($isofile);

This is the same as "$h->isoinfo_device" except that it works for an ISO file located inside some other mounted filesystem. Note that in the common case where you have added an ISO file as a libguestfs device, you would not call this. Instead you would call "$h->isoinfo_device".

%isodata = $h->isoinfo_device ($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>

$h->kill_subprocess ();

This kills the qemu subprocess. You should never need to call this.

$h->launch ();

Internally libguestfs is implemented by running a virtual machine using qemu(1).

 

You should call this after configuring the handle (eg. adding drives) but before performing any actions.

$h->lchown ($owner, $group, $path);

Change the file owner to "owner" and group to "group". This is like "$h->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).

$xattr = $h->lgetxattr ($path, $name);

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 "$h->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: "$h->lgetxattrs", "$h->getxattr", attr(5).

@xattrs = $h->lgetxattrs ($path);

This is the same as "$h->getxattrs", but if "path" is a symbolic link, then it returns the extended attributes of the link itself.

@mounttags = $h->list_9p ();

List all 9p filesystems attached to the guest. A list of mount tags is returned.

@devices = $h->list_devices ();

List all the block devices.

 

The full block device names are returned, eg. "/dev/sda".

 

See also "$h->list_filesystems".

@devices = $h->list_dm_devices ();

List all device mapper devices.

 

The returned list contains "/dev/mapper/*" devices, eg. ones created by a previous call to "$h->luks_open".

 

Device mapper devices which correspond to logical volumes are not returned in this list. Call "$h->lvs" if you want to list logical volumes.

%fses = $h->list_filesystems ();

This inspection command looks for filesystems on partitions, block devices and logical volumes, returning a list of devices 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 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 "$h->mount" and "$h->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 "$h->inspect_os" to look for OSes).

@devices = $h->list_md_devices ();

List all Linux md devices.

@partitions = $h->list_partitions ();

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 "$h->lvs".

 

See also "$h->list_filesystems".

$listing = $h->ll ($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.

$listing = $h->llz ($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.

$h->ln ($target, $linkname);

This command creates a hard link using the "ln" command.

$h->ln_f ($target, $linkname);

This command creates a hard link using the "ln -f" command. The -f option removes the link ("linkname") if it exists already.

$h->ln_s ($target, $linkname);

This command creates a symbolic link using the "ln -s" command.

$h->ln_sf ($target, $linkname);

This command creates a symbolic link using the "ln -sf" command, The -f option removes the link ("linkname") if it exists already.

$h->lremovexattr ($xattr, $path);

This is the same as "$h->removexattr", but if "path" is a symbolic link, then it removes an extended attribute of the link itself.

@listing = $h->ls ($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 command is mostly useful for interactive sessions. Programs should probably use "$h->readdir" instead.

$h->lsetxattr ($xattr, $val, $vallen, $path);

This is the same as "$h->setxattr", but if "path" is a symbolic link, then it sets an extended attribute of the link itself.

%statbuf = $h->lstat ($path);

Returns file information for the given "path".

 

This is the same as "$h->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.

@statbufs = $h->lstatlist ($path, \@names);

This call allows you to perform the "$h->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 "$h->lxattrlist" for a similarly efficient call for getting extended attributes. Very long directory listings might cause the protocol message size to be exceeded, causing this call to fail. The caller must split up such requests into smaller groups of names.

$h->luks_add_key ($device, $key, $newkey, $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 "$h->luks_kill_slot" first to remove that key.

$h->luks_close ($device);

This closes a LUKS device that was created earlier by "$h->luks_open" or "$h->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.

$h->luks_format ($device, $key, $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).

$h->luks_format_cipher ($device, $key, $keyslot, $cipher);

This command is the same as "$h->luks_format" but it also allows you to set the "cipher" used.

$h->luks_kill_slot ($device, $key, $keyslot);

This command deletes the key in key slot "keyslot" from the encrypted LUKS device "device". "key" must be one of the other keys.

$h->luks_open ($device, $key, $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 "$h->vgscan" followed by "$h->vg_activate_all" will make them visible.

 

Use "$h->list_dm_devices" to list all device mapper devices.

$h->luks_open_ro ($device, $key, $mapname);

This is the same as "$h->luks_open" except that a read-only mapping is created.

$h->lvcreate ($logvol, $volgroup, $mbytes);

This creates an LVM logical volume called "logvol" on the volume group "volgroup", with "size" megabytes.

$h->lvcreate_free ($logvol, $volgroup, $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.

$lv = $h->lvm_canonical_lv_name ($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 "$h->is_lv".

$h->lvm_clear_filter ();

This undoes the effect of "$h->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.

$h->lvm_remove_all ();

This command removes all LVM logical volumes, volume groups and physical volumes.

$h->lvm_set_filter (\@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.

$h->lvremove ($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".

$h->lvrename ($logvol, $newlogvol);

Rename a logical volume "logvol" with the new name "newlogvol".

$h->lvresize ($device, $mbytes);

This resizes (expands or shrinks) an existing LVM logical volume to "mbytes". When reducing, data in the reduced part is lost.

$h->lvresize_free ($lv, $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.

@logvols = $h->lvs ();

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 "$h->lvs_full", "$h->list_filesystems".

@logvols = $h->lvs_full ();

List all the logical volumes detected. This is the equivalent of the lvs(8) command. The "full" version includes all fields.

$uuid = $h->lvuuid ($device);

This command returns the UUID of the LVM LV "device".

@xattrs = $h->lxattrlist ($path, \@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 "$h->lstatlist" for a similarly efficient call for getting standard stats. Very long directory listings might cause the protocol message size to be exceeded, causing this call to fail. The caller must split up such requests into smaller groups of names.

$h->md_create ($name, \@devices [, missingbitmap => $missingbitmap] [, nrdevices => $nrdevices] [, spare => $spare] [, chunk => $chunk] [, level => $level]);

Create a Linux md (RAID) device named "name" on the devices in the list "devices".

 

The optional parameters are:

%info = $h->md_detail ($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.

@devices = $h->md_stat ($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 "$h->list_md_devices".

 

Each structure returned corresponds to one device along with additional status information:

$h->md_stop ($md);

This command deactivates the MD array named "md". The device is stopped, but it is not destroyed or zeroed.

$h->mkdir ($path);

Create a directory named "path".

$h->mkdir_mode ($path, $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 "$h->mkdir", "$h->umask"

$h->mkdir_p ($path);

Create a directory named "path", creating any parent directories as necessary. This is like the "mkdir -p" shell command.

$dir = $h->mkdtemp ($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)

$h->mke2fs_J ($fstype, $blocksize, $device, $journal);

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 "$h->mke2journal".

$h->mke2fs_JL ($fstype, $blocksize, $device, $label);

This creates an ext2/3/4 filesystem on "device" with an external journal on the journal labeled "label".

 

See also "$h->mke2journal_L".

$h->mke2fs_JU ($fstype, $blocksize, $device, $uuid);

This creates an ext2/3/4 filesystem on "device" with an external journal on the journal with UUID "uuid".

 

See also "$h->mke2journal_U".

$h->mke2journal ($blocksize, $device);

This creates an ext2 external journal on "device". It is equivalent to the command:

 

 mke2fs -O journal_dev -b blocksize device
    

$h->mke2journal_L ($blocksize, $label, $device);

This creates an ext2 external journal on "device" with label "label".

$h->mke2journal_U ($blocksize, $uuid, $device);

This creates an ext2 external journal on "device" with UUID "uuid".

$h->mkfifo ($mode, $path);

This call creates a FIFO (named pipe) called "path" with mode "mode". It is just a convenient wrapper around "$h->mknod".

 

The mode actually set is affected by the umask.

$h->mkfs ($fstype, $device);

This creates a filesystem on "device" (usually a partition or LVM logical volume). The filesystem type is "fstype", for example "ext3".

$h->mkfs_b ($fstype, $blocksize, $device);

This call is similar to "$h->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 is deprecated. In new code, use the "mkfs_opts" 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.

$h->mkfs_btrfs (\@devices [, allocstart => $allocstart] [, bytecount => $bytecount] [, datatype => $datatype] [, leafsize => $leafsize] [, label => $label] [, metadata => $metadata] [, nodesize => $nodesize] [, sectorsize => $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 "$h->mkfs_opts".

$h->mkfs_opts ($fstype, $device [, blocksize => $blocksize] [, features => $features] [, inode => $inode] [, sectorsize => $sectorsize]);

This function creates a filesystem on "device". The filesystem type is "fstype", for example "ext3".

 

The optional arguments are:

$h->mkmountpoint ($exemptpath);

"$h->mkmountpoint" and "$h->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.

 

"$h->mkmountpoint" is not compatible with "$h->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.

 

"$h->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 "$h->set_autosync", this is set by default on handles] can cause "$h->umount_all" to be called when the handle is closed which can also trigger these issues.

$h->mknod ($mode, $devmajor, $devminor, $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 "$h->mknod_b", "$h->mknod_c" or "$h->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.

$h->mknod_b ($mode, $devmajor, $devminor, $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 "$h->mknod".

 

The mode actually set is affected by the umask.

$h->mknod_c ($mode, $devmajor, $devminor, $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 "$h->mknod".

 

The mode actually set is affected by the umask.

$h->mkswap ($device);

Create a swap partition on "device".

$h->mkswap_L ($label, $device);

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.

$h->mkswap_U ($uuid, $device);

Create a swap partition on "device" with UUID "uuid".

$h->mkswap_file ($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 "$h->fallocate".

$h->modprobe ($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).

$h->mount ($device, $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.

 

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 "$h->mount_options" instead (using an empty string for the first parameter if you don't want any options).

$h->mount_9p ($mounttag, $mountpoint [, options => $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.

$h->mount_local ($localmountpoint [, readonly => $readonly] [, options => $options] [, cachetimeout => $cachetimeout] [, debugcalls => $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 "$h->mount_local" returns, the filesystem is ready, but is not processing requests (access to it will block). You have to call "$h->mount_local_run" to run the main loop.

 

See "MOUNT LOCAL" in guestfs(3) for full documentation.

$h->mount_local_run ();

Run the main loop which translates kernel calls to libguestfs calls.

 

This should only be called after "$h->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, with the exception of "$h->umount_local".

 

You may call this from a different thread than the one which called "$h->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.

$h->mount_loop ($file, $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".

$h->mount_options ($options, $device, $mountpoint);

This is the same as the "$h->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).

$h->mount_ro ($device, $mountpoint);

This is the same as the "$h->mount" command, but it mounts the filesystem with the read-only ( -o ro) flag.

$h->mount_vfs ($options, $vfstype, $device, $mountpoint);

This is the same as the "$h->mount" command, but it allows you to set both the mount options and the vfstype as for the mount(8) -o and -t flags.

%mps = $h->mountpoints ();

This call is similar to "$h->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.

@devices = $h->mounts ();

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: "$h->mountpoints"

$h->mv ($src, $dest);

This moves a file from "src" to "dest" where "dest" is either a destination filename or destination directory.

$status = $h->ntfs_3g_probe ($rw, $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.

$h->ntfsclone_in ($backupfile, $device);

Restore the "backupfile" (from a previous call to "$h->ntfsclone_out") to "device", overwriting any existing contents of this device.

$h->ntfsclone_out ($device, $backupfile [, metadataonly => $metadataonly] [, rescue => $rescue] [, ignorefscheck => $ignorefscheck] [, preservetimestamps => $preservetimestamps] [, force => $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 "$h->ntfsclone_in" to restore the file back to a libguestfs device.

$h->ntfsfix ($device [, clearbadsectors => $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.

$h->ntfsresize ($device);

This command resizes an NTFS filesystem, expanding or shrinking it to the size of the underlying device.

 

Note: After the resize operation, the filesystem is marked as requiring a consistency check (for safety). You have to boot into Windows to perform this check and clear this condition. Furthermore, ntfsresize refuses to resize filesystems which have been marked in this way. So in effect it is not possible to call ntfsresize multiple times on a single filesystem without booting into Windows between each resize.

 

See also ntfsresize(8).

 

This function is deprecated. In new code, use the "ntfsresize_opts" 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.

$h->ntfsresize_opts ($device [, size => $size] [, force => $force]);

This command resizes an NTFS filesystem, expanding or shrinking it to the size of the underlying device.

 

The optional parameters are:

$h->ntfsresize_size ($device, $size);

This command is the same as "$h->ntfsresize" except that it allows you to specify the new size (in bytes) explicitly.

 

This function is deprecated. In new code, use the "ntfsresize_opts" 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.

$h->part_add ($device, $prlogex, $startsect, $endsect);

This command adds a partition to "device". If there is no partition table on the device, call "$h->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 "$h->part_disk" to do that.

$h->part_del ($device, $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.

$h->part_disk ($device, $parttype);

This command is simply a combination of "$h->part_init" followed by "$h->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 "$h->part_init".

$bootable = $h->part_get_bootable ($device, $partnum);

This command returns true if the partition "partnum" on "device" has the bootable flag set.

 

See also "$h->part_set_bootable".

$idbyte = $h->part_get_mbr_id ($device, $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 "$h->part_get_parttype").

$parttype = $h->part_get_parttype ($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 "$h->part_init" for a full list.

$h->part_init ($device, $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 "$h->part_add" for each partition required.

 

Possible values for "parttype" are:

@partitions = $h->part_list ($device);

This command parses the partition table on "device" and returns the list of partitions found.

 

The fields in the returned structure are:

$h->part_set_bootable ($device, $partnum, $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.

$h->part_set_mbr_id ($device, $partnum, $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 "$h->part_get_parttype").

$h->part_set_name ($device, $partnum, $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.

$device = $h->part_to_dev ($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 "$h->list_partitions".

 

See also "$h->part_to_partnum".

$partnum = $h->part_to_partnum ($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 "$h->list_partitions".

 

See also "$h->part_to_dev".

$h->ping_daemon ();

This is a test probe into the guestfs daemon running inside the qemu subprocess. 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.

$content = $h->pread ($path, $count, $offset);

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 "$h->pwrite", "$h->pread_device".

 

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

$content = $h->pread_device ($device, $count, $offset);

This command lets you read part of a file. 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 "$h->pread".

 

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

$h->pvcreate ($device);

This creates an LVM physical volume on the named "device", where "device" should usually be a partition name such as "/dev/sda1".

$h->pvremove ($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.

$h->pvresize ($device);

This resizes (expands or shrinks) an existing LVM physical volume to match the new size of the underlying device.

$h->pvresize_size ($device, $size);

This command is the same as "$h->pvresize" except that it allows you to specify the new size (in bytes) explicitly.

@physvols = $h->pvs ();

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 "$h->pvs_full".

@physvols = $h->pvs_full ();

List all the physical volumes detected. This is the equivalent of the pvs(8) command. The "full" version includes all fields.

$uuid = $h->pvuuid ($device);

This command returns the UUID of the LVM PV "device".

$nbytes = $h->pwrite ($path, $content, $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 "$h->pread", "$h->pwrite_device".

 

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

$nbytes = $h->pwrite_device ($device, $content, $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 "$h->pwrite".

 

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

$content = $h->read_file ($path);

This calls returns the contents of the file "path" as a buffer.

 

Unlike "$h->cat", this function can correctly handle files that contain embedded ASCII NUL characters. However unlike "$h->download", this function is limited in the total size of file that can be handled.

 

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

@lines = $h->read_lines ($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 line). For those you need to use the "$h->read_file" function which has a more complex interface.

@entries = $h->readdir ($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:

$link = $h->readlink ($path);

This command reads the target of a symbolic link.

@links = $h->readlinklist ($path, \@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. Very long directory listings might cause the protocol message size to be exceeded, causing this call to fail. The caller must split up such requests into smaller groups of names.

$rpath = $h->realpath ($path);

Return the canonicalized absolute pathname of "path". The returned path has no ".", ".." or symbolic link path elements.

$h->removexattr ($xattr, $path);

This call removes the extended attribute named "xattr" of the file "path".

 

See also: "$h->lremovexattr", attr(5).

$h->resize2fs ($device);

This resizes an ext2, ext3 or ext4 filesystem to match the size of the underlying device.

 

See also "RESIZE2FS ERRORS" in guestfs(3).

$h->resize2fs_M ($device);

This command is the same as "$h->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 "$h->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).

$h->resize2fs_size ($device, $size);

This command is the same as "$h->resize2fs" except that it allows you to specify the new size (in bytes) explicitly.

 

See also "RESIZE2FS ERRORS" in guestfs(3).

$h->rm ($path);

Remove the single file "path".

$h->rm_rf ($path);

Remove the file or directory "path", recursively removing the contents if its a directory. This is like the "rm -rf" shell command.

$h->rmdir ($path);

Remove the single directory "path".

$h->rmmountpoint ($exemptpath);

This calls removes a mountpoint that was previously created with "$h->mkmountpoint". See "$h->mkmountpoint" for full details.

$h->scrub_device ($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.

$h->scrub_file ($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.

$h->scrub_freespace ($dir);

This command creates the directory "dir" and then fills it with files until the filesystem is full, and scrubs the files as for "$h->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.

$h->set_append ($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).

$h->set_attach_method ($attachmethod);

Set the method that libguestfs uses to connect to the back end guestfsd daemon. Possible methods are:

$h->set_autosync ($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).

$h->set_direct ($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 "$h->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.

$h->set_e2attrs ($file, $attrs [, clear => $clear]);

This sets or clears the file attributes "attrs" associated with the inode "file".

 

"attrs" is a string of characters representing file attributes. See "$h->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.

$h->set_e2generation ($file, $generation);

This sets the ext2 file generation of a file.

 

See "$h->get_e2generation".

$h->set_e2label ($device, $label);

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 "$h->tune2fs_l" or "$h->get_e2label" to return the existing label on a filesystem.

 

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

$h->set_e2uuid ($device, $uuid);

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 either "$h->tune2fs_l" or "$h->get_e2uuid" to return the existing UUID of a filesystem.

$h->set_label ($device, $label);

Set the filesystem label on "device" to "label".

 

Only some filesystem types support labels, and libguestfs supports setting labels on only a subset of these.

 

On ext2/3/4 filesystems, labels are limited to 16 bytes.

 

On NTFS filesystems, labels are limited to 128 unicode characters.

 

To read the label on a filesystem, call "$h->vfs_label".

$h->set_memsize ($memsize);

This sets the memory size in megabytes allocated to the qemu subprocess. This only has any effect if called before "$h->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).

$h->set_network ($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 "$h->launch", otherwise it has no effect.

$h->set_path ($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.

$h->set_pgroup ($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 "$h->user_cancel").

$h->set_qemu ($qemu);

Set the qemu binary 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_QEMU" environment variable.

 

Setting "qemu" 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_QEMU" is safest of all since that picks the qemu binary at the same time as the handle is created.

$h->set_recovery_proc ($recoveryproc);

If this is called with the parameter "false" then "$h->launch" does not create a recovery process. The purpose of the recovery process is to stop runaway qemu processes in the case where the main program aborts abruptly.

 

This only has any effect if called before "$h->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 qemu, which is not very helpful.

$h->set_selinux ($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).

$h->set_smp ($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 "$h->launch".

$h->set_trace ($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 "$h->set_event_callback").

$h->set_verbose ($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 "$h->set_event_callback").

$h->setcon ($context);

This sets the SELinux security context of the daemon to the string "context".

 

See the documentation about SELINUX in guestfs(3).

$h->setxattr ($xattr, $val, $vallen, $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: "$h->lsetxattr", attr(5).

$h->sfdisk ($device, $cyls, $heads, $sectors, \@lines);

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: "$h->sfdisk_l", "$h->sfdisk_N", "$h->part_init"

 

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

$h->sfdiskM ($device, \@lines);

This is a simplified interface to the "$h->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: "$h->sfdisk", the sfdisk(8) manpage and "$h->part_disk"

 

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

$h->sfdisk_N ($device, $partnum, $cyls, $heads, $sectors, $line);

This runs sfdisk(8) option to modify just the single partition "n" (note: "n" counts from 1).

 

For other parameters, see "$h->sfdisk". You should usually pass 0 for the cyls/heads/sectors parameters.

 

See also: "$h->part_add"

 

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

$partitions = $h->sfdisk_disk_geometry ($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 "$h->sfdisk_kernel_geometry").

 

The result is in human-readable format, and not designed to be parsed.

$partitions = $h->sfdisk_kernel_geometry ($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.

$partitions = $h->sfdisk_l ($device);

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: "$h->part_list"

 

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

$output = $h->sh ($command);

This call runs a command from the guest filesystem via the guest's "/bin/sh".

 

This is like "$h->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 "$h->command" apply to this call.

@lines = $h->sh_lines ($command);

This is the same as "$h->sh", but splits the result into a list of lines.

 

See also: "$h->command_lines"

$h->sleep ($secs);

Sleep for "secs" seconds.

%statbuf = $h->stat ($path);

Returns file information for the given "path".

 

This is the same as the stat(2) system call.

%statbuf = $h->statvfs ($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.

@stringsout = $h->strings ($path);

This runs the strings(1) command on a file and returns the list of printable strings found.

 

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

@stringsout = $h->strings_e ($encoding, $path);

This is like the "$h->strings" command, but allows you to specify the encoding of strings that are looked for in the source file "path".

 

Allowed encodings are:

$h->swapoff_device ($device);

This command disables the libguestfs appliance swap device or partition named "device". See "$h->swapon_device".

$h->swapoff_file ($file);

This command disables the libguestfs appliance swap on file.

$h->swapoff_label ($label);

This command disables the libguestfs appliance swap on labeled swap partition.

$h->swapoff_uuid ($uuid);

This command disables the libguestfs appliance swap partition with the given UUID.

$h->swapon_device ($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 "$h->command" or "$h->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.

$h->swapon_file ($file);

This command enables swap to a file. See "$h->swapon_device" for other notes.

$h->swapon_label ($label);

This command enables swap to a labeled swap partition. See "$h->swapon_device" for other notes.

$h->swapon_uuid ($uuid);

This command enables swap to a swap partition with the given UUID. See "$h->swapon_device" for other notes.

$h->sync ();

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.

@lines = $h->tail ($path);

This command returns up to the last 10 lines of a file as a list of strings.

 

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

@lines = $h->tail_n ($nrlines, $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 "-nrlines"th line.

 

If the parameter "nrlines" is zero, this returns an empty list.

 

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

$h->tar_in ($tarfile, $directory);

This command uploads and unpacks local file "tarfile" (an uncompressed tar file) into "directory".

 

To upload a compressed tarball, use "$h->tgz_in" or "$h->txz_in".

$h->tar_out ($directory, $tarfile);

This command packs the contents of "directory" and downloads it to local file "tarfile".

 

To download a compressed tarball, use "$h->tgz_out" or "$h->txz_out".

$h->tgz_in ($tarball, $directory);

This command uploads and unpacks local file "tarball" (a gzip compressed tar file) into "directory".

 

To upload an uncompressed tarball, use "$h->tar_in".

$h->tgz_out ($directory, $tarball);

This command packs the contents of "directory" and downloads it to local file "tarball".

 

To download an uncompressed tarball, use "$h->tar_out".

$h->touch ($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.

$h->truncate ($path);

This command truncates "path" to a zero-length file. The file must exist already.

$h->truncate_size ($path, $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 "$h->fallocate64" instead.

$h->tune2fs ($device [, force => $force] [, maxmountcount => $maxmountcount] [, mountcount => $mountcount] [, errorbehavior => $errorbehavior] [, group => $group] [, intervalbetweenchecks => $intervalbetweenchecks] [, reservedblockspercentage => $reservedblockspercentage] [, lastmounteddirectory => $lastmounteddirectory] [, reservedblockscount => $reservedblockscount] [, user => $user]);

This call allows you to adjust various filesystem parameters of an ext2/ext3/ext4 filesystem called "device".

 

The optional parameters are:

%superblock = $h->tune2fs_l ($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.

$h->txz_in ($tarball, $directory);

This command uploads and unpacks local file "tarball" (an xz compressed tar file) into "directory".

$h->txz_out ($directory, $tarball);

This command packs the contents of "directory" and downloads it to local file "tarball" (as an xz compressed tar archive).

$oldmask = $h->umask ($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 "$h->get_umask", umask(2), "$h->mknod", "$h->mkdir".

 

This call returns the previous umask.

$h->umount ($pathordevice);

This unmounts the given filesystem. The filesystem may be specified either by its mountpoint (path) or the device which contains the filesystem.

$h->umount_all ();

This unmounts all mounted filesystems.

 

Some internal mounts are not unmounted by this call.

$h->umount_local ([retry => $retry]);

If libguestfs is exporting the filesystem on a local mountpoint, then this unmounts it.

 

See "MOUNT LOCAL" in guestfs(3) for full documentation.

$h->upload ($filename, $remotefilename);

Upload local file "filename" to "remotefilename" on the filesystem.

 

"filename" can also be a named pipe.

 

See also "$h->download".

$h->upload_offset ($filename, $remotefilename, $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 "$h->pwrite", and this call always writes the full amount unless an error occurs.

 

See also "$h->upload", "$h->pwrite".

$h->utimens ($path, $atsecs, $atnsecs, $mtsecs, $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).

%version = $h->version ();

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 "$h->available" instead.

$label = $h->vfs_label ($device);

This returns the filesystem label of the filesystem on "device".

 

If the filesystem is unlabeled, this returns the empty string.

 

To find a filesystem from the label, use "$h->findfs_label".

$fstype = $h->vfs_type ($device);

This command gets the filesystem type corresponding to the filesystem on "device".

 

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".

$uuid = $h->vfs_uuid ($device);

This returns the filesystem UUID of the filesystem on "device".

 

If the filesystem does not have a UUID, this returns the empty string.

 

To find a filesystem from the UUID, use "$h->findfs_uuid".

$h->vg_activate ($activate, \@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.

$h->vg_activate_all ($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"

$h->vgcreate ($volgroup, \@physvols);

This creates an LVM volume group called "volgroup" from the non-empty list of physical volumes "physvols".

@uuids = $h->vglvuuids ($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 "$h->lvs" and "$h->lvuuid" calls to associate logical volumes and volume groups.

 

See also "$h->vgpvuuids".

$metadata = $h->vgmeta ($vgname);

"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.

@uuids = $h->vgpvuuids ($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 "$h->pvs" and "$h->pvuuid" calls to associate physical volumes and volume groups.

 

See also "$h->vglvuuids".

$h->vgremove ($vgname);

Remove an LVM volume group "vgname", (for example "VG").

 

This also forcibly removes all logical volumes in the volume group (if any).

$h->vgrename ($volgroup, $newvolgroup);

Rename a volume group "volgroup" with the new name "newvolgroup".

@volgroups = $h->vgs ();

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 "$h->vgs_full".

@volgroups = $h->vgs_full ();

List all the volumes groups detected. This is the equivalent of the vgs(8) command. The "full" version includes all fields.

$h->vgscan ();

This rescans all block devices and rebuilds the list of LVM physical volumes, volume groups and logical volumes.

$uuid = $h->vguuid ($vgname);

This command returns the UUID of the LVM VG named "vgname".

$h->wait_ready ();

This function is a no op.

 

In versions of the API < 1.0.71 you had to call this function just after calling "$h->launch" to wait for the launch to complete. However this is no longer necessary because "$h->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 is deprecated. In new code, use the "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.

$chars = $h->wc_c ($path);

This command counts the characters in a file, using the "wc -c" external command.

$lines = $h->wc_l ($path);

This command counts the lines in a file, using the "wc -l" external command.

$words = $h->wc_w ($path);

This command counts the words in a file, using the "wc -w" external command.

$h->wipefs ($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 "$h->zero" which zeroes the first few blocks of a device.

$h->write ($path, $content);

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 "$h->write_append".

 

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

$h->write_append ($path, $content);

This call appends "content" to the end of file "path". If "path" does not exist, then a new file is created.

 

See also "$h->write".

 

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

$h->write_file ($path, $content, $size);

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.

 

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

 

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

@lines = $h->zegrep ($regex, $path);

This calls the external "zegrep" program and returns the matching lines.

 

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

@lines = $h->zegrepi ($regex, $path);

This calls the external "zegrep -i" program and returns the matching lines.

 

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

$h->zero ($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: "$h->zero_device", "$h->scrub_device", "$h->is_zero_device"

$h->zero_device ($device);

This command writes zeroes over the entire "device". Compare with "$h->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.

$h->zero_free_space ($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.

 

In future (but not currently) these zeroed blocks will be "sparsified" - that is, given back to the host.

$h->zerofree ($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.

@lines = $h->zfgrep ($pattern, $path);

This calls the external "zfgrep" program and returns the matching lines.

 

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

@lines = $h->zfgrepi ($pattern, $path);

This calls the external "zfgrep -i" program and returns the matching lines.

 

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

$description = $h->zfile ($meth, $path);

This command runs "file" after first decompressing "path" using "method".

 

"method" must be one of "gzip", "compress" or "bzip2".

 

Since 1.0.63, use "$h->file" instead which can now process compressed files.

 

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

@lines = $h->zgrep ($regex, $path);

This calls the external "zgrep" program and returns the matching lines.

 

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

@lines = $h->zgrepi ($regex, $path);

This calls the external "zgrep -i" program and returns the matching lines.

 

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

AVAILABILITY¶

From time to time we add new libguestfs APIs. Also some libguestfs APIs won't be available in all builds of libguestfs (the Fedora build is full-featured, but other builds may disable features). How do you test whether the APIs that your Perl program needs are available in the version of "Sys::Guestfs" that you are using? To test if a particular function is available in the "Sys::Guestfs" class, use the ordinary Perl UNIVERSAL method "can(METHOD)" (see perlobj(1)). For example:

 use Sys::Guestfs;
 if (defined (Sys::Guestfs->can ("set_verbose"))) {
   print "\$h->set_verbose is available\n";
 }

Perl does not offer a way to list the arguments of a method, and from time to time we may add extra arguments to calls that take optional arguments. For this reason, we provide a global hash variable %guestfs_introspection which contains the arguments and their types for each libguestfs method. The keys of this hash are the method names, and the values are an hashref containing useful introspection information about the method (further fields may be added to this in future).

 use Sys::Guestfs;
 $Sys::Guestfs::guestfs_introspection{mkfs_opts}
 => {
    ret => 'void',                    # return type
    args => [                         # required arguments
      [ 'fstype', 'string', 0 ],
      [ 'device', 'string(device)', 1 ],
    ],
    optargs => {                      # optional arguments
      blocksize => [ 'blocksize', 'int', 0 ],
      features => [ 'features', 'string', 1 ],
      inode => [ 'inode', 'int', 2 ],
      sectorsize => [ 'sectorsize', 'int', 3 ],
    },
    name => "mkfs_opts",
    description => "make a filesystem",
  }

To test if particular features are supported by the current build, use the "available" method like the example below. Note that the appliance must be launched first.

 $h->available ( ["augeas"] );

Since the "available" method croaks if the feature is not supported, you might also want to wrap this in an eval and return a boolean. In fact this has already been done for you: use "feature_available" in Sys::Guestfs::Lib(3). For further discussion on this topic, refer to "AVAILABILITY" in guestfs(3).

STORING DATA IN THE HANDLE¶

The handle returned from "new" is a hash reference. The hash normally contains a single element:

 {
   _g => [private data used by libguestfs]
 }

Callers can add other elements to this hash to store data for their own purposes. The data lasts for the lifetime of the handle. Any fields whose names begin with an underscore are reserved for private use by libguestfs. We may add more in future. It is recommended that callers prefix the name of their field(s) with some unique string, to avoid conflicts with other users.

COPYRIGHT¶

Copyright (C) 2009-2013 Red Hat Inc.

LICENSE¶

Please see the file COPYING.LIB for the full license.

SEE ALSO¶

guestfs(3), guestfish(1), <http://libguestfs.org>, Sys::Guestfs::Lib(3).