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7 # This library is free software; you can redistribute it and/or
8 # modify it under the terms of the GNU Lesser General Public
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12 # This library is distributed in the hope that it will be useful,
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14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 # Lesser General Public License for more details.
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25 Sys::Guestfs - Perl bindings for libguestfs
31 my $h = Sys::Guestfs->new ();
32 $h->add_drive ('guest.img');
35 $h->mount ('/dev/sda1', '/');
41 The C<Sys::Guestfs> module provides a Perl XS binding to the
42 libguestfs API for examining and modifying virtual machine
45 Amongst the things this is good for: making batch configuration
46 changes to guests, getting disk used/free statistics (see also:
47 virt-df), migrating between virtualization systems (see also:
48 virt-p2v), performing partial backups, performing partial guest
49 clones, cloning guests and changing registry/UUID/hostname info, and
52 Libguestfs uses Linux kernel and qemu code, and can access any type of
53 guest filesystem that Linux and qemu can, including but not limited
54 to: ext2/3/4, btrfs, FAT and NTFS, LVM, many different disk partition
55 schemes, qcow, qcow2, vmdk.
57 Libguestfs provides ways to enumerate guest storage (eg. partitions,
58 LVs, what filesystem is in each LV, etc.). It can also run commands
59 in the context of the guest. Also you can access filesystems over FTP.
63 All errors turn into calls to C<croak> (see L<Carp(3)>).
77 XSLoader::load ('Sys::Guestfs');
79 =item $h = Sys::Guestfs->new ();
81 Create a new guestfs handle.
87 my $class = ref ($proto) || $proto;
89 my $self = Sys::Guestfs::_create ();
94 =item $h->add_cdrom ($filename);
96 This function adds a virtual CD-ROM disk image to the guest.
98 This is equivalent to the qemu parameter C<-cdrom filename>.
100 Note that this call checks for the existence of C<filename>. This
101 stops you from specifying other types of drive which are supported
102 by qemu such as C<nbd:> and C<http:> URLs. To specify those, use
103 the general C<$h-E<gt>config> call instead.
105 =item $h->add_drive ($filename);
107 This function adds a virtual machine disk image C<filename> to the
108 guest. The first time you call this function, the disk appears as IDE
109 disk 0 (C</dev/sda>) in the guest, the second time as C</dev/sdb>, and
112 You don't necessarily need to be root when using libguestfs. However
113 you obviously do need sufficient permissions to access the filename
114 for whatever operations you want to perform (ie. read access if you
115 just want to read the image or write access if you want to modify the
118 This is equivalent to the qemu parameter C<-drive file=filename>.
120 Note that this call checks for the existence of C<filename>. This
121 stops you from specifying other types of drive which are supported
122 by qemu such as C<nbd:> and C<http:> URLs. To specify those, use
123 the general C<$h-E<gt>config> call instead.
125 =item $h->add_drive_ro ($filename);
127 This adds a drive in snapshot mode, making it effectively
130 Note that writes to the device are allowed, and will be seen for
131 the duration of the guestfs handle, but they are written
132 to a temporary file which is discarded as soon as the guestfs
133 handle is closed. We don't currently have any method to enable
134 changes to be committed, although qemu can support this.
136 This is equivalent to the qemu parameter
137 C<-drive file=filename,snapshot=on>.
139 Note that this call checks for the existence of C<filename>. This
140 stops you from specifying other types of drive which are supported
141 by qemu such as C<nbd:> and C<http:> URLs. To specify those, use
142 the general C<$h-E<gt>config> call instead.
144 =item $h->aug_close ();
146 Close the current Augeas handle and free up any resources
147 used by it. After calling this, you have to call
148 C<$h-E<gt>aug_init> again before you can use any other
151 =item ($nrnodes, $created) = $h->aug_defnode ($name, $expr, $val);
153 Defines a variable C<name> whose value is the result of
156 If C<expr> evaluates to an empty nodeset, a node is created,
157 equivalent to calling C<$h-E<gt>aug_set> C<expr>, C<value>.
158 C<name> will be the nodeset containing that single node.
160 On success this returns a pair containing the
161 number of nodes in the nodeset, and a boolean flag
162 if a node was created.
164 =item $nrnodes = $h->aug_defvar ($name, $expr);
166 Defines an Augeas variable C<name> whose value is the result
167 of evaluating C<expr>. If C<expr> is NULL, then C<name> is
170 On success this returns the number of nodes in C<expr>, or
171 C<0> if C<expr> evaluates to something which is not a nodeset.
173 =item $val = $h->aug_get ($path);
175 Look up the value associated with C<path>. If C<path>
176 matches exactly one node, the C<value> is returned.
178 =item $h->aug_init ($root, $flags);
180 Create a new Augeas handle for editing configuration files.
181 If there was any previous Augeas handle associated with this
182 guestfs session, then it is closed.
184 You must call this before using any other C<$h-E<gt>aug_*>
187 C<root> is the filesystem root. C<root> must not be NULL,
190 The flags are the same as the flags defined in
191 E<lt>augeas.hE<gt>, the logical I<or> of the following
196 =item C<AUG_SAVE_BACKUP> = 1
198 Keep the original file with a C<.augsave> extension.
200 =item C<AUG_SAVE_NEWFILE> = 2
202 Save changes into a file with extension C<.augnew>, and
203 do not overwrite original. Overrides C<AUG_SAVE_BACKUP>.
205 =item C<AUG_TYPE_CHECK> = 4
207 Typecheck lenses (can be expensive).
209 =item C<AUG_NO_STDINC> = 8
211 Do not use standard load path for modules.
213 =item C<AUG_SAVE_NOOP> = 16
215 Make save a no-op, just record what would have been changed.
217 =item C<AUG_NO_LOAD> = 32
219 Do not load the tree in C<$h-E<gt>aug_init>.
223 To close the handle, you can call C<$h-E<gt>aug_close>.
225 To find out more about Augeas, see L<http://augeas.net/>.
227 =item $h->aug_insert ($path, $label, $before);
229 Create a new sibling C<label> for C<path>, inserting it into
230 the tree before or after C<path> (depending on the boolean
233 C<path> must match exactly one existing node in the tree, and
234 C<label> must be a label, ie. not contain C</>, C<*> or end
235 with a bracketed index C<[N]>.
237 =item $h->aug_load ();
239 Load files into the tree.
241 See C<aug_load> in the Augeas documentation for the full gory
244 =item @matches = $h->aug_ls ($path);
246 This is just a shortcut for listing C<$h-E<gt>aug_match>
247 C<path/*> and sorting the resulting nodes into alphabetical order.
249 =item @matches = $h->aug_match ($path);
251 Returns a list of paths which match the path expression C<path>.
252 The returned paths are sufficiently qualified so that they match
253 exactly one node in the current tree.
255 =item $h->aug_mv ($src, $dest);
257 Move the node C<src> to C<dest>. C<src> must match exactly
258 one node. C<dest> is overwritten if it exists.
260 =item $nrnodes = $h->aug_rm ($path);
262 Remove C<path> and all of its children.
264 On success this returns the number of entries which were removed.
266 =item $h->aug_save ();
268 This writes all pending changes to disk.
270 The flags which were passed to C<$h-E<gt>aug_init> affect exactly
273 =item $h->aug_set ($path, $val);
275 Set the value associated with C<path> to C<value>.
277 =item $h->blockdev_flushbufs ($device);
279 This tells the kernel to flush internal buffers associated
282 This uses the L<blockdev(8)> command.
284 =item $blocksize = $h->blockdev_getbsz ($device);
286 This returns the block size of a device.
288 (Note this is different from both I<size in blocks> and
289 I<filesystem block size>).
291 This uses the L<blockdev(8)> command.
293 =item $ro = $h->blockdev_getro ($device);
295 Returns a boolean indicating if the block device is read-only
296 (true if read-only, false if not).
298 This uses the L<blockdev(8)> command.
300 =item $sizeinbytes = $h->blockdev_getsize64 ($device);
302 This returns the size of the device in bytes.
304 See also C<$h-E<gt>blockdev_getsz>.
306 This uses the L<blockdev(8)> command.
308 =item $sectorsize = $h->blockdev_getss ($device);
310 This returns the size of sectors on a block device.
311 Usually 512, but can be larger for modern devices.
313 (Note, this is not the size in sectors, use C<$h-E<gt>blockdev_getsz>
316 This uses the L<blockdev(8)> command.
318 =item $sizeinsectors = $h->blockdev_getsz ($device);
320 This returns the size of the device in units of 512-byte sectors
321 (even if the sectorsize isn't 512 bytes ... weird).
323 See also C<$h-E<gt>blockdev_getss> for the real sector size of
324 the device, and C<$h-E<gt>blockdev_getsize64> for the more
325 useful I<size in bytes>.
327 This uses the L<blockdev(8)> command.
329 =item $h->blockdev_rereadpt ($device);
331 Reread the partition table on C<device>.
333 This uses the L<blockdev(8)> command.
335 =item $h->blockdev_setbsz ($device, $blocksize);
337 This sets the block size of a device.
339 (Note this is different from both I<size in blocks> and
340 I<filesystem block size>).
342 This uses the L<blockdev(8)> command.
344 =item $h->blockdev_setro ($device);
346 Sets the block device named C<device> to read-only.
348 This uses the L<blockdev(8)> command.
350 =item $h->blockdev_setrw ($device);
352 Sets the block device named C<device> to read-write.
354 This uses the L<blockdev(8)> command.
356 =item $content = $h->cat ($path);
358 Return the contents of the file named C<path>.
360 Note that this function cannot correctly handle binary files
361 (specifically, files containing C<\0> character which is treated
362 as end of string). For those you need to use the C<$h-E<gt>download>
363 function which has a more complex interface.
365 Because of the message protocol, there is a transfer limit
366 of somewhere between 2MB and 4MB. To transfer large files you should use
369 =item $checksum = $h->checksum ($csumtype, $path);
371 This call computes the MD5, SHAx or CRC checksum of the
374 The type of checksum to compute is given by the C<csumtype>
375 parameter which must have one of the following values:
381 Compute the cyclic redundancy check (CRC) specified by POSIX
382 for the C<cksum> command.
386 Compute the MD5 hash (using the C<md5sum> program).
390 Compute the SHA1 hash (using the C<sha1sum> program).
394 Compute the SHA224 hash (using the C<sha224sum> program).
398 Compute the SHA256 hash (using the C<sha256sum> program).
402 Compute the SHA384 hash (using the C<sha384sum> program).
406 Compute the SHA512 hash (using the C<sha512sum> program).
410 The checksum is returned as a printable string.
412 =item $h->chmod ($mode, $path);
414 Change the mode (permissions) of C<path> to C<mode>. Only
415 numeric modes are supported.
417 =item $h->chown ($owner, $group, $path);
419 Change the file owner to C<owner> and group to C<group>.
421 Only numeric uid and gid are supported. If you want to use
422 names, you will need to locate and parse the password file
423 yourself (Augeas support makes this relatively easy).
425 =item $output = $h->command (\@arguments);
427 This call runs a command from the guest filesystem. The
428 filesystem must be mounted, and must contain a compatible
429 operating system (ie. something Linux, with the same
430 or compatible processor architecture).
432 The single parameter is an argv-style list of arguments.
433 The first element is the name of the program to run.
434 Subsequent elements are parameters. The list must be
435 non-empty (ie. must contain a program name). Note that
436 the command runs directly, and is I<not> invoked via
437 the shell (see C<$h-E<gt>sh>).
439 The return value is anything printed to I<stdout> by
442 If the command returns a non-zero exit status, then
443 this function returns an error message. The error message
444 string is the content of I<stderr> from the command.
446 The C<$PATH> environment variable will contain at least
447 C</usr/bin> and C</bin>. If you require a program from
448 another location, you should provide the full path in the
451 Shared libraries and data files required by the program
452 must be available on filesystems which are mounted in the
453 correct places. It is the caller's responsibility to ensure
454 all filesystems that are needed are mounted at the right
457 Because of the message protocol, there is a transfer limit
458 of somewhere between 2MB and 4MB. To transfer large files you should use
461 =item @lines = $h->command_lines (\@arguments);
463 This is the same as C<$h-E<gt>command>, but splits the
464 result into a list of lines.
466 See also: C<$h-E<gt>sh_lines>
468 Because of the message protocol, there is a transfer limit
469 of somewhere between 2MB and 4MB. To transfer large files you should use
472 =item $h->config ($qemuparam, $qemuvalue);
474 This can be used to add arbitrary qemu command line parameters
475 of the form C<-param value>. Actually it's not quite arbitrary - we
476 prevent you from setting some parameters which would interfere with
477 parameters that we use.
479 The first character of C<param> string must be a C<-> (dash).
481 C<value> can be NULL.
483 =item $h->cp ($src, $dest);
485 This copies a file from C<src> to C<dest> where C<dest> is
486 either a destination filename or destination directory.
488 =item $h->cp_a ($src, $dest);
490 This copies a file or directory from C<src> to C<dest>
491 recursively using the C<cp -a> command.
493 =item $result = $h->debug ($subcmd, \@extraargs);
495 The C<$h-E<gt>debug> command exposes some internals of
496 C<guestfsd> (the guestfs daemon) that runs inside the
499 There is no comprehensive help for this command. You have
500 to look at the file C<daemon/debug.c> in the libguestfs source
501 to find out what you can do.
503 =item $kmsgs = $h->dmesg ();
505 This returns the kernel messages (C<dmesg> output) from
506 the guest kernel. This is sometimes useful for extended
507 debugging of problems.
509 Another way to get the same information is to enable
510 verbose messages with C<$h-E<gt>set_verbose> or by setting
511 the environment variable C<LIBGUESTFS_DEBUG=1> before
514 =item $h->download ($remotefilename, $filename);
516 Download file C<remotefilename> and save it as C<filename>
517 on the local machine.
519 C<filename> can also be a named pipe.
521 See also C<$h-E<gt>upload>, C<$h-E<gt>cat>.
523 =item $h->drop_caches ($whattodrop);
525 This instructs the guest kernel to drop its page cache,
526 and/or dentries and inode caches. The parameter C<whattodrop>
527 tells the kernel what precisely to drop, see
528 L<http://linux-mm.org/Drop_Caches>
530 Setting C<whattodrop> to 3 should drop everything.
532 This automatically calls L<sync(2)> before the operation,
533 so that the maximum guest memory is freed.
535 =item $h->e2fsck_f ($device);
537 This runs C<e2fsck -p -f device>, ie. runs the ext2/ext3
538 filesystem checker on C<device>, noninteractively (C<-p>),
539 even if the filesystem appears to be clean (C<-f>).
541 This command is only needed because of C<$h-E<gt>resize2fs>
542 (q.v.). Normally you should use C<$h-E<gt>fsck>.
544 =item $h->end_busy ();
546 This sets the state to C<READY>, or if in C<CONFIG> then it leaves the
547 state as is. This is only used when implementing
548 actions using the low-level API.
550 For more information on states, see L<guestfs(3)>.
552 =item $equality = $h->equal ($file1, $file2);
554 This compares the two files C<file1> and C<file2> and returns
555 true if their content is exactly equal, or false otherwise.
557 The external L<cmp(1)> program is used for the comparison.
559 =item $existsflag = $h->exists ($path);
561 This returns C<true> if and only if there is a file, directory
562 (or anything) with the given C<path> name.
564 See also C<$h-E<gt>is_file>, C<$h-E<gt>is_dir>, C<$h-E<gt>stat>.
566 =item $description = $h->file ($path);
568 This call uses the standard L<file(1)> command to determine
569 the type or contents of the file. This also works on devices,
570 for example to find out whether a partition contains a filesystem.
572 The exact command which runs is C<file -bsL path>. Note in
573 particular that the filename is not prepended to the output
576 =item @names = $h->find ($directory);
578 This command lists out all files and directories, recursively,
579 starting at C<directory>. It is essentially equivalent to
580 running the shell command C<find directory -print> but some
581 post-processing happens on the output, described below.
583 This returns a list of strings I<without any prefix>. Thus
584 if the directory structure was:
590 then the returned list from C<$h-E<gt>find> C</tmp> would be
598 If C<directory> is not a directory, then this command returns
601 The returned list is sorted.
603 =item $status = $h->fsck ($fstype, $device);
605 This runs the filesystem checker (fsck) on C<device> which
606 should have filesystem type C<fstype>.
608 The returned integer is the status. See L<fsck(8)> for the
609 list of status codes from C<fsck>.
617 Multiple status codes can be summed together.
621 A non-zero return code can mean "success", for example if
622 errors have been corrected on the filesystem.
626 Checking or repairing NTFS volumes is not supported
631 This command is entirely equivalent to running C<fsck -a -t fstype device>.
633 =item $append = $h->get_append ();
635 Return the additional kernel options which are added to the
636 guest kernel command line.
638 If C<NULL> then no options are added.
640 =item $autosync = $h->get_autosync ();
642 Get the autosync flag.
644 =item $label = $h->get_e2label ($device);
646 This returns the ext2/3/4 filesystem label of the filesystem on
649 =item $uuid = $h->get_e2uuid ($device);
651 This returns the ext2/3/4 filesystem UUID of the filesystem on
654 =item $path = $h->get_path ();
656 Return the current search path.
658 This is always non-NULL. If it wasn't set already, then this will
659 return the default path.
661 =item $qemu = $h->get_qemu ();
663 Return the current qemu binary.
665 This is always non-NULL. If it wasn't set already, then this will
666 return the default qemu binary name.
668 =item $state = $h->get_state ();
670 This returns the current state as an opaque integer. This is
671 only useful for printing debug and internal error messages.
673 For more information on states, see L<guestfs(3)>.
675 =item $verbose = $h->get_verbose ();
677 This returns the verbose messages flag.
679 =item $h->grub_install ($root, $device);
681 This command installs GRUB (the Grand Unified Bootloader) on
682 C<device>, with the root directory being C<root>.
684 =item $dump = $h->hexdump ($path);
686 This runs C<hexdump -C> on the given C<path>. The result is
687 the human-readable, canonical hex dump of the file.
689 Because of the message protocol, there is a transfer limit
690 of somewhere between 2MB and 4MB. To transfer large files you should use
693 =item $busy = $h->is_busy ();
695 This returns true iff this handle is busy processing a command
696 (in the C<BUSY> state).
698 For more information on states, see L<guestfs(3)>.
700 =item $config = $h->is_config ();
702 This returns true iff this handle is being configured
703 (in the C<CONFIG> state).
705 For more information on states, see L<guestfs(3)>.
707 =item $dirflag = $h->is_dir ($path);
709 This returns C<true> if and only if there is a directory
710 with the given C<path> name. Note that it returns false for
711 other objects like files.
713 See also C<$h-E<gt>stat>.
715 =item $fileflag = $h->is_file ($path);
717 This returns C<true> if and only if there is a file
718 with the given C<path> name. Note that it returns false for
719 other objects like directories.
721 See also C<$h-E<gt>stat>.
723 =item $launching = $h->is_launching ();
725 This returns true iff this handle is launching the subprocess
726 (in the C<LAUNCHING> state).
728 For more information on states, see L<guestfs(3)>.
730 =item $ready = $h->is_ready ();
732 This returns true iff this handle is ready to accept commands
733 (in the C<READY> state).
735 For more information on states, see L<guestfs(3)>.
737 =item $h->kill_subprocess ();
739 This kills the qemu subprocess. You should never need to call this.
743 Internally libguestfs is implemented by running a virtual machine
746 You should call this after configuring the handle
747 (eg. adding drives) but before performing any actions.
749 =item @devices = $h->list_devices ();
751 List all the block devices.
753 The full block device names are returned, eg. C</dev/sda>
755 =item @partitions = $h->list_partitions ();
757 List all the partitions detected on all block devices.
759 The full partition device names are returned, eg. C</dev/sda1>
761 This does not return logical volumes. For that you will need to
764 =item $listing = $h->ll ($directory);
766 List the files in C<directory> (relative to the root directory,
767 there is no cwd) in the format of 'ls -la'.
769 This command is mostly useful for interactive sessions. It
770 is I<not> intended that you try to parse the output string.
772 =item @listing = $h->ls ($directory);
774 List the files in C<directory> (relative to the root directory,
775 there is no cwd). The '.' and '..' entries are not returned, but
776 hidden files are shown.
778 This command is mostly useful for interactive sessions. Programs
779 should probably use C<$h-E<gt>readdir> instead.
781 =item %statbuf = $h->lstat ($path);
783 Returns file information for the given C<path>.
785 This is the same as C<$h-E<gt>stat> except that if C<path>
786 is a symbolic link, then the link is stat-ed, not the file it
789 This is the same as the C<lstat(2)> system call.
791 =item $h->lvcreate ($logvol, $volgroup, $mbytes);
793 This creates an LVM volume group called C<logvol>
794 on the volume group C<volgroup>, with C<size> megabytes.
796 =item $h->lvm_remove_all ();
798 This command removes all LVM logical volumes, volume groups
799 and physical volumes.
801 B<This command is dangerous. Without careful use you
802 can easily destroy all your data>.
804 =item $h->lvremove ($device);
806 Remove an LVM logical volume C<device>, where C<device> is
807 the path to the LV, such as C</dev/VG/LV>.
809 You can also remove all LVs in a volume group by specifying
810 the VG name, C</dev/VG>.
812 =item $h->lvresize ($device, $mbytes);
814 This resizes (expands or shrinks) an existing LVM logical
815 volume to C<mbytes>. When reducing, data in the reduced part
818 =item @logvols = $h->lvs ();
820 List all the logical volumes detected. This is the equivalent
821 of the L<lvs(8)> command.
823 This returns a list of the logical volume device names
824 (eg. C</dev/VolGroup00/LogVol00>).
826 See also C<$h-E<gt>lvs_full>.
828 =item @logvols = $h->lvs_full ();
830 List all the logical volumes detected. This is the equivalent
831 of the L<lvs(8)> command. The "full" version includes all fields.
833 =item $h->mkdir ($path);
835 Create a directory named C<path>.
837 =item $h->mkdir_p ($path);
839 Create a directory named C<path>, creating any parent directories
840 as necessary. This is like the C<mkdir -p> shell command.
842 =item $h->mkfs ($fstype, $device);
844 This creates a filesystem on C<device> (usually a partition
845 or LVM logical volume). The filesystem type is C<fstype>, for
848 =item $h->mount ($device, $mountpoint);
850 Mount a guest disk at a position in the filesystem. Block devices
851 are named C</dev/sda>, C</dev/sdb> and so on, as they were added to
852 the guest. If those block devices contain partitions, they will have
853 the usual names (eg. C</dev/sda1>). Also LVM C</dev/VG/LV>-style
856 The rules are the same as for L<mount(2)>: A filesystem must
857 first be mounted on C</> before others can be mounted. Other
858 filesystems can only be mounted on directories which already
861 The mounted filesystem is writable, if we have sufficient permissions
862 on the underlying device.
864 The filesystem options C<sync> and C<noatime> are set with this
865 call, in order to improve reliability.
867 =item $h->mount_options ($options, $device, $mountpoint);
869 This is the same as the C<$h-E<gt>mount> command, but it
870 allows you to set the mount options as for the
871 L<mount(8)> I<-o> flag.
873 =item $h->mount_ro ($device, $mountpoint);
875 This is the same as the C<$h-E<gt>mount> command, but it
876 mounts the filesystem with the read-only (I<-o ro>) flag.
878 =item $h->mount_vfs ($options, $vfstype, $device, $mountpoint);
880 This is the same as the C<$h-E<gt>mount> command, but it
881 allows you to set both the mount options and the vfstype
882 as for the L<mount(8)> I<-o> and I<-t> flags.
884 =item @devices = $h->mounts ();
886 This returns the list of currently mounted filesystems. It returns
887 the list of devices (eg. C</dev/sda1>, C</dev/VG/LV>).
889 Some internal mounts are not shown.
891 =item $h->mv ($src, $dest);
893 This moves a file from C<src> to C<dest> where C<dest> is
894 either a destination filename or destination directory.
896 =item $status = $h->ntfs_3g_probe ($rw, $device);
898 This command runs the L<ntfs-3g.probe(8)> command which probes
899 an NTFS C<device> for mountability. (Not all NTFS volumes can
900 be mounted read-write, and some cannot be mounted at all).
902 C<rw> is a boolean flag. Set it to true if you want to test
903 if the volume can be mounted read-write. Set it to false if
904 you want to test if the volume can be mounted read-only.
906 The return value is an integer which C<0> if the operation
907 would succeed, or some non-zero value documented in the
908 L<ntfs-3g.probe(8)> manual page.
910 =item $h->ping_daemon ();
912 This is a test probe into the guestfs daemon running inside
913 the qemu subprocess. Calling this function checks that the
914 daemon responds to the ping message, without affecting the daemon
915 or attached block device(s) in any other way.
917 =item $h->pvcreate ($device);
919 This creates an LVM physical volume on the named C<device>,
920 where C<device> should usually be a partition name such
923 =item $h->pvremove ($device);
925 This wipes a physical volume C<device> so that LVM will no longer
928 The implementation uses the C<pvremove> command which refuses to
929 wipe physical volumes that contain any volume groups, so you have
930 to remove those first.
932 =item $h->pvresize ($device);
934 This resizes (expands or shrinks) an existing LVM physical
935 volume to match the new size of the underlying device.
937 =item @physvols = $h->pvs ();
939 List all the physical volumes detected. This is the equivalent
940 of the L<pvs(8)> command.
942 This returns a list of just the device names that contain
943 PVs (eg. C</dev/sda2>).
945 See also C<$h-E<gt>pvs_full>.
947 =item @physvols = $h->pvs_full ();
949 List all the physical volumes detected. This is the equivalent
950 of the L<pvs(8)> command. The "full" version includes all fields.
952 =item @lines = $h->read_lines ($path);
954 Return the contents of the file named C<path>.
956 The file contents are returned as a list of lines. Trailing
957 C<LF> and C<CRLF> character sequences are I<not> returned.
959 Note that this function cannot correctly handle binary files
960 (specifically, files containing C<\0> character which is treated
961 as end of line). For those you need to use the C<$h-E<gt>read_file>
962 function which has a more complex interface.
964 =item $h->resize2fs ($device);
966 This resizes an ext2 or ext3 filesystem to match the size of
967 the underlying device.
969 I<Note:> It is sometimes required that you run C<$h-E<gt>e2fsck_f>
970 on the C<device> before calling this command. For unknown reasons
971 C<resize2fs> sometimes gives an error about this and sometimes not.
972 In any case, it is always safe to call C<$h-E<gt>e2fsck_f> before
973 calling this function.
975 =item $h->rm ($path);
977 Remove the single file C<path>.
979 =item $h->rm_rf ($path);
981 Remove the file or directory C<path>, recursively removing the
982 contents if its a directory. This is like the C<rm -rf> shell
985 =item $h->rmdir ($path);
987 Remove the single directory C<path>.
989 =item $h->set_append ($append);
991 This function is used to add additional options to the
992 guest kernel command line.
994 The default is C<NULL> unless overridden by setting
995 C<LIBGUESTFS_APPEND> environment variable.
997 Setting C<append> to C<NULL> means I<no> additional options
998 are passed (libguestfs always adds a few of its own).
1000 =item $h->set_autosync ($autosync);
1002 If C<autosync> is true, this enables autosync. Libguestfs will make a
1003 best effort attempt to run C<$h-E<gt>umount_all> followed by
1004 C<$h-E<gt>sync> when the handle is closed
1005 (also if the program exits without closing handles).
1007 This is disabled by default (except in guestfish where it is
1008 enabled by default).
1010 =item $h->set_busy ();
1012 This sets the state to C<BUSY>. This is only used when implementing
1013 actions using the low-level API.
1015 For more information on states, see L<guestfs(3)>.
1017 =item $h->set_e2label ($device, $label);
1019 This sets the ext2/3/4 filesystem label of the filesystem on
1020 C<device> to C<label>. Filesystem labels are limited to
1023 You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2label>
1024 to return the existing label on a filesystem.
1026 =item $h->set_e2uuid ($device, $uuid);
1028 This sets the ext2/3/4 filesystem UUID of the filesystem on
1029 C<device> to C<uuid>. The format of the UUID and alternatives
1030 such as C<clear>, C<random> and C<time> are described in the
1031 L<tune2fs(8)> manpage.
1033 You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2uuid>
1034 to return the existing UUID of a filesystem.
1036 =item $h->set_path ($path);
1038 Set the path that libguestfs searches for kernel and initrd.img.
1040 The default is C<$libdir/guestfs> unless overridden by setting
1041 C<LIBGUESTFS_PATH> environment variable.
1043 Setting C<path> to C<NULL> restores the default path.
1045 =item $h->set_qemu ($qemu);
1047 Set the qemu binary that we will use.
1049 The default is chosen when the library was compiled by the
1052 You can also override this by setting the C<LIBGUESTFS_QEMU>
1053 environment variable.
1055 Setting C<qemu> to C<NULL> restores the default qemu binary.
1057 =item $h->set_ready ();
1059 This sets the state to C<READY>. This is only used when implementing
1060 actions using the low-level API.
1062 For more information on states, see L<guestfs(3)>.
1064 =item $h->set_verbose ($verbose);
1066 If C<verbose> is true, this turns on verbose messages (to C<stderr>).
1068 Verbose messages are disabled unless the environment variable
1069 C<LIBGUESTFS_DEBUG> is defined and set to C<1>.
1071 =item $h->sfdisk ($device, $cyls, $heads, $sectors, \@lines);
1073 This is a direct interface to the L<sfdisk(8)> program for creating
1074 partitions on block devices.
1076 C<device> should be a block device, for example C</dev/sda>.
1078 C<cyls>, C<heads> and C<sectors> are the number of cylinders, heads
1079 and sectors on the device, which are passed directly to sfdisk as
1080 the I<-C>, I<-H> and I<-S> parameters. If you pass C<0> for any
1081 of these, then the corresponding parameter is omitted. Usually for
1082 'large' disks, you can just pass C<0> for these, but for small
1083 (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work
1084 out the right geometry and you will need to tell it.
1086 C<lines> is a list of lines that we feed to C<sfdisk>. For more
1087 information refer to the L<sfdisk(8)> manpage.
1089 To create a single partition occupying the whole disk, you would
1090 pass C<lines> as a single element list, when the single element being
1091 the string C<,> (comma).
1093 See also: C<$h-E<gt>sfdisk_l>, C<$h-E<gt>sfdisk_N>
1095 B<This command is dangerous. Without careful use you
1096 can easily destroy all your data>.
1098 =item $h->sfdisk_N ($device, $n, $cyls, $heads, $sectors, $line);
1100 This runs L<sfdisk(8)> option to modify just the single
1101 partition C<n> (note: C<n> counts from 1).
1103 For other parameters, see C<$h-E<gt>sfdisk>. You should usually
1104 pass C<0> for the cyls/heads/sectors parameters.
1106 B<This command is dangerous. Without careful use you
1107 can easily destroy all your data>.
1109 =item $partitions = $h->sfdisk_disk_geometry ($device);
1111 This displays the disk geometry of C<device> read from the
1112 partition table. Especially in the case where the underlying
1113 block device has been resized, this can be different from the
1114 kernel's idea of the geometry (see C<$h-E<gt>sfdisk_kernel_geometry>).
1116 The result is in human-readable format, and not designed to
1119 =item $partitions = $h->sfdisk_kernel_geometry ($device);
1121 This displays the kernel's idea of the geometry of C<device>.
1123 The result is in human-readable format, and not designed to
1126 =item $partitions = $h->sfdisk_l ($device);
1128 This displays the partition table on C<device>, in the
1129 human-readable output of the L<sfdisk(8)> command. It is
1130 not intended to be parsed.
1132 =item $output = $h->sh ($command);
1134 This call runs a command from the guest filesystem via the
1137 This is like C<$h-E<gt>command>, but passes the command to:
1139 /bin/sh -c "command"
1141 Depending on the guest's shell, this usually results in
1142 wildcards being expanded, shell expressions being interpolated
1145 All the provisos about C<$h-E<gt>command> apply to this call.
1147 =item @lines = $h->sh_lines ($command);
1149 This is the same as C<$h-E<gt>sh>, but splits the result
1150 into a list of lines.
1152 See also: C<$h-E<gt>command_lines>
1154 =item $h->sleep ($secs);
1156 Sleep for C<secs> seconds.
1158 =item %statbuf = $h->stat ($path);
1160 Returns file information for the given C<path>.
1162 This is the same as the C<stat(2)> system call.
1164 =item %statbuf = $h->statvfs ($path);
1166 Returns file system statistics for any mounted file system.
1167 C<path> should be a file or directory in the mounted file system
1168 (typically it is the mount point itself, but it doesn't need to be).
1170 This is the same as the C<statvfs(2)> system call.
1172 =item @stringsout = $h->strings ($path);
1174 This runs the L<strings(1)> command on a file and returns
1175 the list of printable strings found.
1177 Because of the message protocol, there is a transfer limit
1178 of somewhere between 2MB and 4MB. To transfer large files you should use
1181 =item @stringsout = $h->strings_e ($encoding, $path);
1183 This is like the C<$h-E<gt>strings> command, but allows you to
1184 specify the encoding.
1186 See the L<strings(1)> manpage for the full list of encodings.
1188 Commonly useful encodings are C<l> (lower case L) which will
1189 show strings inside Windows/x86 files.
1191 The returned strings are transcoded to UTF-8.
1193 Because of the message protocol, there is a transfer limit
1194 of somewhere between 2MB and 4MB. To transfer large files you should use
1199 This syncs the disk, so that any writes are flushed through to the
1200 underlying disk image.
1202 You should always call this if you have modified a disk image, before
1205 =item $h->tar_in ($tarfile, $directory);
1207 This command uploads and unpacks local file C<tarfile> (an
1208 I<uncompressed> tar file) into C<directory>.
1210 To upload a compressed tarball, use C<$h-E<gt>tgz_in>.
1212 =item $h->tar_out ($directory, $tarfile);
1214 This command packs the contents of C<directory> and downloads
1215 it to local file C<tarfile>.
1217 To download a compressed tarball, use C<$h-E<gt>tgz_out>.
1219 =item $h->tgz_in ($tarball, $directory);
1221 This command uploads and unpacks local file C<tarball> (a
1222 I<gzip compressed> tar file) into C<directory>.
1224 To upload an uncompressed tarball, use C<$h-E<gt>tar_in>.
1226 =item $h->tgz_out ($directory, $tarball);
1228 This command packs the contents of C<directory> and downloads
1229 it to local file C<tarball>.
1231 To download an uncompressed tarball, use C<$h-E<gt>tar_out>.
1233 =item $h->touch ($path);
1235 Touch acts like the L<touch(1)> command. It can be used to
1236 update the timestamps on a file, or, if the file does not exist,
1237 to create a new zero-length file.
1239 =item %superblock = $h->tune2fs_l ($device);
1241 This returns the contents of the ext2, ext3 or ext4 filesystem
1242 superblock on C<device>.
1244 It is the same as running C<tune2fs -l device>. See L<tune2fs(8)>
1245 manpage for more details. The list of fields returned isn't
1246 clearly defined, and depends on both the version of C<tune2fs>
1247 that libguestfs was built against, and the filesystem itself.
1249 =item $h->umount ($pathordevice);
1251 This unmounts the given filesystem. The filesystem may be
1252 specified either by its mountpoint (path) or the device which
1253 contains the filesystem.
1255 =item $h->umount_all ();
1257 This unmounts all mounted filesystems.
1259 Some internal mounts are not unmounted by this call.
1261 =item $h->upload ($filename, $remotefilename);
1263 Upload local file C<filename> to C<remotefilename> on the
1266 C<filename> can also be a named pipe.
1268 See also C<$h-E<gt>download>.
1270 =item $h->vg_activate ($activate, \@volgroups);
1272 This command activates or (if C<activate> is false) deactivates
1273 all logical volumes in the listed volume groups C<volgroups>.
1274 If activated, then they are made known to the
1275 kernel, ie. they appear as C</dev/mapper> devices. If deactivated,
1276 then those devices disappear.
1278 This command is the same as running C<vgchange -a y|n volgroups...>
1280 Note that if C<volgroups> is an empty list then B<all> volume groups
1281 are activated or deactivated.
1283 =item $h->vg_activate_all ($activate);
1285 This command activates or (if C<activate> is false) deactivates
1286 all logical volumes in all volume groups.
1287 If activated, then they are made known to the
1288 kernel, ie. they appear as C</dev/mapper> devices. If deactivated,
1289 then those devices disappear.
1291 This command is the same as running C<vgchange -a y|n>
1293 =item $h->vgcreate ($volgroup, \@physvols);
1295 This creates an LVM volume group called C<volgroup>
1296 from the non-empty list of physical volumes C<physvols>.
1298 =item $h->vgremove ($vgname);
1300 Remove an LVM volume group C<vgname>, (for example C<VG>).
1302 This also forcibly removes all logical volumes in the volume
1305 =item @volgroups = $h->vgs ();
1307 List all the volumes groups detected. This is the equivalent
1308 of the L<vgs(8)> command.
1310 This returns a list of just the volume group names that were
1311 detected (eg. C<VolGroup00>).
1313 See also C<$h-E<gt>vgs_full>.
1315 =item @volgroups = $h->vgs_full ();
1317 List all the volumes groups detected. This is the equivalent
1318 of the L<vgs(8)> command. The "full" version includes all fields.
1320 =item $h->wait_ready ();
1322 Internally libguestfs is implemented by running a virtual machine
1325 You should call this after C<$h-E<gt>launch> to wait for the launch
1328 =item $h->write_file ($path, $content, $size);
1330 This call creates a file called C<path>. The contents of the
1331 file is the string C<content> (which can contain any 8 bit data),
1332 with length C<size>.
1334 As a special case, if C<size> is C<0>
1335 then the length is calculated using C<strlen> (so in this case
1336 the content cannot contain embedded ASCII NULs).
1338 I<NB.> Owing to a bug, writing content containing ASCII NUL
1339 characters does I<not> work, even if the length is specified.
1340 We hope to resolve this bug in a future version. In the meantime
1341 use C<$h-E<gt>upload>.
1343 Because of the message protocol, there is a transfer limit
1344 of somewhere between 2MB and 4MB. To transfer large files you should use
1347 =item $h->zero ($device);
1349 This command writes zeroes over the first few blocks of C<device>.
1351 How many blocks are zeroed isn't specified (but it's I<not> enough
1352 to securely wipe the device). It should be sufficient to remove
1353 any partition tables, filesystem superblocks and so on.
1355 =item $h->zerofree ($device);
1357 This runs the I<zerofree> program on C<device>. This program
1358 claims to zero unused inodes and disk blocks on an ext2/3
1359 filesystem, thus making it possible to compress the filesystem
1362 You should B<not> run this program if the filesystem is
1365 It is possible that using this program can damage the filesystem
1366 or data on the filesystem.
1376 Copyright (C) 2009 Red Hat Inc.
1380 Please see the file COPYING.LIB for the full license.
1384 L<guestfs(3)>, L<guestfish(1)>.