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8 # modify it under the terms of the GNU Lesser General Public
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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 = $h->command (\@arguments);
427 This call runs a command from the guest filesystem. The
428 filesystem must be mounted, and must contain a compatible
429 operating system (ie. something Linux, with the same
430 or compatible processor architecture).
432 The single parameter is an argv-style list of arguments.
433 The first element is the name of the program to run.
434 Subsequent elements are parameters. The list must be
435 non-empty (ie. must contain a program name).
437 The return value is anything printed to I<stdout> by
440 If the command returns a non-zero exit status, then
441 this function returns an error message. The error message
442 string is the content of I<stderr> from the command.
444 The C<$PATH> environment variable will contain at least
445 C</usr/bin> and C</bin>. If you require a program from
446 another location, you should provide the full path in the
449 Shared libraries and data files required by the program
450 must be available on filesystems which are mounted in the
451 correct places. It is the caller's responsibility to ensure
452 all filesystems that are needed are mounted at the right
455 Because of the message protocol, there is a transfer limit
456 of somewhere between 2MB and 4MB. To transfer large files you should use
459 =item @lines = $h->command_lines (\@arguments);
461 This is the same as C<$h-E<gt>command>, but splits the
462 result into a list of lines.
464 Because of the message protocol, there is a transfer limit
465 of somewhere between 2MB and 4MB. To transfer large files you should use
468 =item $h->config ($qemuparam, $qemuvalue);
470 This can be used to add arbitrary qemu command line parameters
471 of the form C<-param value>. Actually it's not quite arbitrary - we
472 prevent you from setting some parameters which would interfere with
473 parameters that we use.
475 The first character of C<param> string must be a C<-> (dash).
477 C<value> can be NULL.
479 =item $h->cp ($src, $dest);
481 This copies a file from C<src> to C<dest> where C<dest> is
482 either a destination filename or destination directory.
484 =item $h->cp_a ($src, $dest);
486 This copies a file or directory from C<src> to C<dest>
487 recursively using the C<cp -a> command.
489 =item $result = $h->debug ($subcmd, \@extraargs);
491 The C<$h-E<gt>debug> command exposes some internals of
492 C<guestfsd> (the guestfs daemon) that runs inside the
495 There is no comprehensive help for this command. You have
496 to look at the file C<daemon/debug.c> in the libguestfs source
497 to find out what you can do.
499 =item $kmsgs = $h->dmesg ();
501 This returns the kernel messages (C<dmesg> output) from
502 the guest kernel. This is sometimes useful for extended
503 debugging of problems.
505 Another way to get the same information is to enable
506 verbose messages with C<$h-E<gt>set_verbose> or by setting
507 the environment variable C<LIBGUESTFS_DEBUG=1> before
510 =item $h->download ($remotefilename, $filename);
512 Download file C<remotefilename> and save it as C<filename>
513 on the local machine.
515 C<filename> can also be a named pipe.
517 See also C<$h-E<gt>upload>, C<$h-E<gt>cat>.
519 =item $h->drop_caches ($whattodrop);
521 This instructs the guest kernel to drop its page cache,
522 and/or dentries and inode caches. The parameter C<whattodrop>
523 tells the kernel what precisely to drop, see
524 L<http://linux-mm.org/Drop_Caches>
526 Setting C<whattodrop> to 3 should drop everything.
528 This automatically calls L<sync(2)> before the operation,
529 so that the maximum guest memory is freed.
531 =item $h->e2fsck_f ($device);
533 This runs C<e2fsck -p -f device>, ie. runs the ext2/ext3
534 filesystem checker on C<device>, noninteractively (C<-p>),
535 even if the filesystem appears to be clean (C<-f>).
537 This command is only needed because of C<$h-E<gt>resize2fs>
538 (q.v.). Normally you should use C<$h-E<gt>fsck>.
540 =item $h->end_busy ();
542 This sets the state to C<READY>, or if in C<CONFIG> then it leaves the
543 state as is. This is only used when implementing
544 actions using the low-level API.
546 For more information on states, see L<guestfs(3)>.
548 =item $equality = $h->equal ($file1, $file2);
550 This compares the two files C<file1> and C<file2> and returns
551 true if their content is exactly equal, or false otherwise.
553 The external L<cmp(1)> program is used for the comparison.
555 =item $existsflag = $h->exists ($path);
557 This returns C<true> if and only if there is a file, directory
558 (or anything) with the given C<path> name.
560 See also C<$h-E<gt>is_file>, C<$h-E<gt>is_dir>, C<$h-E<gt>stat>.
562 =item $description = $h->file ($path);
564 This call uses the standard L<file(1)> command to determine
565 the type or contents of the file. This also works on devices,
566 for example to find out whether a partition contains a filesystem.
568 The exact command which runs is C<file -bsL path>. Note in
569 particular that the filename is not prepended to the output
572 =item @names = $h->find ($directory);
574 This command lists out all files and directories, recursively,
575 starting at C<directory>. It is essentially equivalent to
576 running the shell command C<find directory -print> but some
577 post-processing happens on the output, described below.
579 This returns a list of strings I<without any prefix>. Thus
580 if the directory structure was:
586 then the returned list from C<$h-E<gt>find> C</tmp> would be
594 If C<directory> is not a directory, then this command returns
597 The returned list is sorted.
599 =item $status = $h->fsck ($fstype, $device);
601 This runs the filesystem checker (fsck) on C<device> which
602 should have filesystem type C<fstype>.
604 The returned integer is the status. See L<fsck(8)> for the
605 list of status codes from C<fsck>.
613 Multiple status codes can be summed together.
617 A non-zero return code can mean "success", for example if
618 errors have been corrected on the filesystem.
622 Checking or repairing NTFS volumes is not supported
627 This command is entirely equivalent to running C<fsck -a -t fstype device>.
629 =item $append = $h->get_append ();
631 Return the additional kernel options which are added to the
632 guest kernel command line.
634 If C<NULL> then no options are added.
636 =item $autosync = $h->get_autosync ();
638 Get the autosync flag.
640 =item $label = $h->get_e2label ($device);
642 This returns the ext2/3/4 filesystem label of the filesystem on
645 =item $uuid = $h->get_e2uuid ($device);
647 This returns the ext2/3/4 filesystem UUID of the filesystem on
650 =item $path = $h->get_path ();
652 Return the current search path.
654 This is always non-NULL. If it wasn't set already, then this will
655 return the default path.
657 =item $qemu = $h->get_qemu ();
659 Return the current qemu binary.
661 This is always non-NULL. If it wasn't set already, then this will
662 return the default qemu binary name.
664 =item $state = $h->get_state ();
666 This returns the current state as an opaque integer. This is
667 only useful for printing debug and internal error messages.
669 For more information on states, see L<guestfs(3)>.
671 =item $verbose = $h->get_verbose ();
673 This returns the verbose messages flag.
675 =item $h->grub_install ($root, $device);
677 This command installs GRUB (the Grand Unified Bootloader) on
678 C<device>, with the root directory being C<root>.
680 =item $dump = $h->hexdump ($path);
682 This runs C<hexdump -C> on the given C<path>. The result is
683 the human-readable, canonical hex dump of the file.
685 Because of the message protocol, there is a transfer limit
686 of somewhere between 2MB and 4MB. To transfer large files you should use
689 =item $busy = $h->is_busy ();
691 This returns true iff this handle is busy processing a command
692 (in the C<BUSY> state).
694 For more information on states, see L<guestfs(3)>.
696 =item $config = $h->is_config ();
698 This returns true iff this handle is being configured
699 (in the C<CONFIG> state).
701 For more information on states, see L<guestfs(3)>.
703 =item $dirflag = $h->is_dir ($path);
705 This returns C<true> if and only if there is a directory
706 with the given C<path> name. Note that it returns false for
707 other objects like files.
709 See also C<$h-E<gt>stat>.
711 =item $fileflag = $h->is_file ($path);
713 This returns C<true> if and only if there is a file
714 with the given C<path> name. Note that it returns false for
715 other objects like directories.
717 See also C<$h-E<gt>stat>.
719 =item $launching = $h->is_launching ();
721 This returns true iff this handle is launching the subprocess
722 (in the C<LAUNCHING> state).
724 For more information on states, see L<guestfs(3)>.
726 =item $ready = $h->is_ready ();
728 This returns true iff this handle is ready to accept commands
729 (in the C<READY> state).
731 For more information on states, see L<guestfs(3)>.
733 =item $h->kill_subprocess ();
735 This kills the qemu subprocess. You should never need to call this.
739 Internally libguestfs is implemented by running a virtual machine
742 You should call this after configuring the handle
743 (eg. adding drives) but before performing any actions.
745 =item @devices = $h->list_devices ();
747 List all the block devices.
749 The full block device names are returned, eg. C</dev/sda>
751 =item @partitions = $h->list_partitions ();
753 List all the partitions detected on all block devices.
755 The full partition device names are returned, eg. C</dev/sda1>
757 This does not return logical volumes. For that you will need to
760 =item $listing = $h->ll ($directory);
762 List the files in C<directory> (relative to the root directory,
763 there is no cwd) in the format of 'ls -la'.
765 This command is mostly useful for interactive sessions. It
766 is I<not> intended that you try to parse the output string.
768 =item @listing = $h->ls ($directory);
770 List the files in C<directory> (relative to the root directory,
771 there is no cwd). The '.' and '..' entries are not returned, but
772 hidden files are shown.
774 This command is mostly useful for interactive sessions. Programs
775 should probably use C<$h-E<gt>readdir> instead.
777 =item %statbuf = $h->lstat ($path);
779 Returns file information for the given C<path>.
781 This is the same as C<$h-E<gt>stat> except that if C<path>
782 is a symbolic link, then the link is stat-ed, not the file it
785 This is the same as the C<lstat(2)> system call.
787 =item $h->lvcreate ($logvol, $volgroup, $mbytes);
789 This creates an LVM volume group called C<logvol>
790 on the volume group C<volgroup>, with C<size> megabytes.
792 =item $h->lvm_remove_all ();
794 This command removes all LVM logical volumes, volume groups
795 and physical volumes.
797 B<This command is dangerous. Without careful use you
798 can easily destroy all your data>.
800 =item $h->lvremove ($device);
802 Remove an LVM logical volume C<device>, where C<device> is
803 the path to the LV, such as C</dev/VG/LV>.
805 You can also remove all LVs in a volume group by specifying
806 the VG name, C</dev/VG>.
808 =item $h->lvresize ($device, $mbytes);
810 This resizes (expands or shrinks) an existing LVM logical
811 volume to C<mbytes>. When reducing, data in the reduced part
814 =item @logvols = $h->lvs ();
816 List all the logical volumes detected. This is the equivalent
817 of the L<lvs(8)> command.
819 This returns a list of the logical volume device names
820 (eg. C</dev/VolGroup00/LogVol00>).
822 See also C<$h-E<gt>lvs_full>.
824 =item @logvols = $h->lvs_full ();
826 List all the logical volumes detected. This is the equivalent
827 of the L<lvs(8)> command. The "full" version includes all fields.
829 =item $h->mkdir ($path);
831 Create a directory named C<path>.
833 =item $h->mkdir_p ($path);
835 Create a directory named C<path>, creating any parent directories
836 as necessary. This is like the C<mkdir -p> shell command.
838 =item $h->mkfs ($fstype, $device);
840 This creates a filesystem on C<device> (usually a partition
841 or LVM logical volume). The filesystem type is C<fstype>, for
844 =item $h->mount ($device, $mountpoint);
846 Mount a guest disk at a position in the filesystem. Block devices
847 are named C</dev/sda>, C</dev/sdb> and so on, as they were added to
848 the guest. If those block devices contain partitions, they will have
849 the usual names (eg. C</dev/sda1>). Also LVM C</dev/VG/LV>-style
852 The rules are the same as for L<mount(2)>: A filesystem must
853 first be mounted on C</> before others can be mounted. Other
854 filesystems can only be mounted on directories which already
857 The mounted filesystem is writable, if we have sufficient permissions
858 on the underlying device.
860 The filesystem options C<sync> and C<noatime> are set with this
861 call, in order to improve reliability.
863 =item $h->mount_options ($options, $device, $mountpoint);
865 This is the same as the C<$h-E<gt>mount> command, but it
866 allows you to set the mount options as for the
867 L<mount(8)> I<-o> flag.
869 =item $h->mount_ro ($device, $mountpoint);
871 This is the same as the C<$h-E<gt>mount> command, but it
872 mounts the filesystem with the read-only (I<-o ro>) flag.
874 =item $h->mount_vfs ($options, $vfstype, $device, $mountpoint);
876 This is the same as the C<$h-E<gt>mount> command, but it
877 allows you to set both the mount options and the vfstype
878 as for the L<mount(8)> I<-o> and I<-t> flags.
880 =item @devices = $h->mounts ();
882 This returns the list of currently mounted filesystems. It returns
883 the list of devices (eg. C</dev/sda1>, C</dev/VG/LV>).
885 Some internal mounts are not shown.
887 =item $h->mv ($src, $dest);
889 This moves a file from C<src> to C<dest> where C<dest> is
890 either a destination filename or destination directory.
892 =item $status = $h->ntfs_3g_probe ($rw, $device);
894 This command runs the L<ntfs-3g.probe(8)> command which probes
895 an NTFS C<device> for mountability. (Not all NTFS volumes can
896 be mounted read-write, and some cannot be mounted at all).
898 C<rw> is a boolean flag. Set it to true if you want to test
899 if the volume can be mounted read-write. Set it to false if
900 you want to test if the volume can be mounted read-only.
902 The return value is an integer which C<0> if the operation
903 would succeed, or some non-zero value documented in the
904 L<ntfs-3g.probe(8)> manual page.
906 =item $h->ping_daemon ();
908 This is a test probe into the guestfs daemon running inside
909 the qemu subprocess. Calling this function checks that the
910 daemon responds to the ping message, without affecting the daemon
911 or attached block device(s) in any other way.
913 =item $h->pvcreate ($device);
915 This creates an LVM physical volume on the named C<device>,
916 where C<device> should usually be a partition name such
919 =item $h->pvremove ($device);
921 This wipes a physical volume C<device> so that LVM will no longer
924 The implementation uses the C<pvremove> command which refuses to
925 wipe physical volumes that contain any volume groups, so you have
926 to remove those first.
928 =item $h->pvresize ($device);
930 This resizes (expands or shrinks) an existing LVM physical
931 volume to match the new size of the underlying device.
933 =item @physvols = $h->pvs ();
935 List all the physical volumes detected. This is the equivalent
936 of the L<pvs(8)> command.
938 This returns a list of just the device names that contain
939 PVs (eg. C</dev/sda2>).
941 See also C<$h-E<gt>pvs_full>.
943 =item @physvols = $h->pvs_full ();
945 List all the physical volumes detected. This is the equivalent
946 of the L<pvs(8)> command. The "full" version includes all fields.
948 =item @lines = $h->read_lines ($path);
950 Return the contents of the file named C<path>.
952 The file contents are returned as a list of lines. Trailing
953 C<LF> and C<CRLF> character sequences are I<not> returned.
955 Note that this function cannot correctly handle binary files
956 (specifically, files containing C<\0> character which is treated
957 as end of line). For those you need to use the C<$h-E<gt>read_file>
958 function which has a more complex interface.
960 =item $h->resize2fs ($device);
962 This resizes an ext2 or ext3 filesystem to match the size of
963 the underlying device.
965 I<Note:> It is sometimes required that you run C<$h-E<gt>e2fsck_f>
966 on the C<device> before calling this command. For unknown reasons
967 C<resize2fs> sometimes gives an error about this and sometimes not.
968 In any case, it is always safe to call C<$h-E<gt>e2fsck_f> before
969 calling this function.
971 =item $h->rm ($path);
973 Remove the single file C<path>.
975 =item $h->rm_rf ($path);
977 Remove the file or directory C<path>, recursively removing the
978 contents if its a directory. This is like the C<rm -rf> shell
981 =item $h->rmdir ($path);
983 Remove the single directory C<path>.
985 =item $h->set_append ($append);
987 This function is used to add additional options to the
988 guest kernel command line.
990 The default is C<NULL> unless overridden by setting
991 C<LIBGUESTFS_APPEND> environment variable.
993 Setting C<append> to C<NULL> means I<no> additional options
994 are passed (libguestfs always adds a few of its own).
996 =item $h->set_autosync ($autosync);
998 If C<autosync> is true, this enables autosync. Libguestfs will make a
999 best effort attempt to run C<$h-E<gt>umount_all> followed by
1000 C<$h-E<gt>sync> when the handle is closed
1001 (also if the program exits without closing handles).
1003 This is disabled by default (except in guestfish where it is
1004 enabled by default).
1006 =item $h->set_busy ();
1008 This sets the state to C<BUSY>. This is only used when implementing
1009 actions using the low-level API.
1011 For more information on states, see L<guestfs(3)>.
1013 =item $h->set_e2label ($device, $label);
1015 This sets the ext2/3/4 filesystem label of the filesystem on
1016 C<device> to C<label>. Filesystem labels are limited to
1019 You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2label>
1020 to return the existing label on a filesystem.
1022 =item $h->set_e2uuid ($device, $uuid);
1024 This sets the ext2/3/4 filesystem UUID of the filesystem on
1025 C<device> to C<uuid>. The format of the UUID and alternatives
1026 such as C<clear>, C<random> and C<time> are described in the
1027 L<tune2fs(8)> manpage.
1029 You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2uuid>
1030 to return the existing UUID of a filesystem.
1032 =item $h->set_path ($path);
1034 Set the path that libguestfs searches for kernel and initrd.img.
1036 The default is C<$libdir/guestfs> unless overridden by setting
1037 C<LIBGUESTFS_PATH> environment variable.
1039 Setting C<path> to C<NULL> restores the default path.
1041 =item $h->set_qemu ($qemu);
1043 Set the qemu binary that we will use.
1045 The default is chosen when the library was compiled by the
1048 You can also override this by setting the C<LIBGUESTFS_QEMU>
1049 environment variable.
1051 Setting C<qemu> to C<NULL> restores the default qemu binary.
1053 =item $h->set_ready ();
1055 This sets the state to C<READY>. This is only used when implementing
1056 actions using the low-level API.
1058 For more information on states, see L<guestfs(3)>.
1060 =item $h->set_verbose ($verbose);
1062 If C<verbose> is true, this turns on verbose messages (to C<stderr>).
1064 Verbose messages are disabled unless the environment variable
1065 C<LIBGUESTFS_DEBUG> is defined and set to C<1>.
1067 =item $h->sfdisk ($device, $cyls, $heads, $sectors, \@lines);
1069 This is a direct interface to the L<sfdisk(8)> program for creating
1070 partitions on block devices.
1072 C<device> should be a block device, for example C</dev/sda>.
1074 C<cyls>, C<heads> and C<sectors> are the number of cylinders, heads
1075 and sectors on the device, which are passed directly to sfdisk as
1076 the I<-C>, I<-H> and I<-S> parameters. If you pass C<0> for any
1077 of these, then the corresponding parameter is omitted. Usually for
1078 'large' disks, you can just pass C<0> for these, but for small
1079 (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work
1080 out the right geometry and you will need to tell it.
1082 C<lines> is a list of lines that we feed to C<sfdisk>. For more
1083 information refer to the L<sfdisk(8)> manpage.
1085 To create a single partition occupying the whole disk, you would
1086 pass C<lines> as a single element list, when the single element being
1087 the string C<,> (comma).
1089 See also: C<$h-E<gt>sfdisk_l>, C<$h-E<gt>sfdisk_N>
1091 B<This command is dangerous. Without careful use you
1092 can easily destroy all your data>.
1094 =item $h->sfdisk_N ($device, $n, $cyls, $heads, $sectors, $line);
1096 This runs L<sfdisk(8)> option to modify just the single
1097 partition C<n> (note: C<n> counts from 1).
1099 For other parameters, see C<$h-E<gt>sfdisk>. You should usually
1100 pass C<0> for the cyls/heads/sectors parameters.
1102 B<This command is dangerous. Without careful use you
1103 can easily destroy all your data>.
1105 =item $partitions = $h->sfdisk_disk_geometry ($device);
1107 This displays the disk geometry of C<device> read from the
1108 partition table. Especially in the case where the underlying
1109 block device has been resized, this can be different from the
1110 kernel's idea of the geometry (see C<$h-E<gt>sfdisk_kernel_geometry>).
1112 The result is in human-readable format, and not designed to
1115 =item $partitions = $h->sfdisk_kernel_geometry ($device);
1117 This displays the kernel's idea of the geometry of C<device>.
1119 The result is in human-readable format, and not designed to
1122 =item $partitions = $h->sfdisk_l ($device);
1124 This displays the partition table on C<device>, in the
1125 human-readable output of the L<sfdisk(8)> command. It is
1126 not intended to be parsed.
1128 =item $h->sleep ($secs);
1130 Sleep for C<secs> seconds.
1132 =item %statbuf = $h->stat ($path);
1134 Returns file information for the given C<path>.
1136 This is the same as the C<stat(2)> system call.
1138 =item %statbuf = $h->statvfs ($path);
1140 Returns file system statistics for any mounted file system.
1141 C<path> should be a file or directory in the mounted file system
1142 (typically it is the mount point itself, but it doesn't need to be).
1144 This is the same as the C<statvfs(2)> system call.
1146 =item @stringsout = $h->strings ($path);
1148 This runs the L<strings(1)> command on a file and returns
1149 the list of printable strings found.
1151 Because of the message protocol, there is a transfer limit
1152 of somewhere between 2MB and 4MB. To transfer large files you should use
1155 =item @stringsout = $h->strings_e ($encoding, $path);
1157 This is like the C<$h-E<gt>strings> command, but allows you to
1158 specify the encoding.
1160 See the L<strings(1)> manpage for the full list of encodings.
1162 Commonly useful encodings are C<l> (lower case L) which will
1163 show strings inside Windows/x86 files.
1165 The returned strings are transcoded to UTF-8.
1167 Because of the message protocol, there is a transfer limit
1168 of somewhere between 2MB and 4MB. To transfer large files you should use
1173 This syncs the disk, so that any writes are flushed through to the
1174 underlying disk image.
1176 You should always call this if you have modified a disk image, before
1179 =item $h->tar_in ($tarfile, $directory);
1181 This command uploads and unpacks local file C<tarfile> (an
1182 I<uncompressed> tar file) into C<directory>.
1184 To upload a compressed tarball, use C<$h-E<gt>tgz_in>.
1186 =item $h->tar_out ($directory, $tarfile);
1188 This command packs the contents of C<directory> and downloads
1189 it to local file C<tarfile>.
1191 To download a compressed tarball, use C<$h-E<gt>tgz_out>.
1193 =item $h->tgz_in ($tarball, $directory);
1195 This command uploads and unpacks local file C<tarball> (a
1196 I<gzip compressed> tar file) into C<directory>.
1198 To upload an uncompressed tarball, use C<$h-E<gt>tar_in>.
1200 =item $h->tgz_out ($directory, $tarball);
1202 This command packs the contents of C<directory> and downloads
1203 it to local file C<tarball>.
1205 To download an uncompressed tarball, use C<$h-E<gt>tar_out>.
1207 =item $h->touch ($path);
1209 Touch acts like the L<touch(1)> command. It can be used to
1210 update the timestamps on a file, or, if the file does not exist,
1211 to create a new zero-length file.
1213 =item %superblock = $h->tune2fs_l ($device);
1215 This returns the contents of the ext2, ext3 or ext4 filesystem
1216 superblock on C<device>.
1218 It is the same as running C<tune2fs -l device>. See L<tune2fs(8)>
1219 manpage for more details. The list of fields returned isn't
1220 clearly defined, and depends on both the version of C<tune2fs>
1221 that libguestfs was built against, and the filesystem itself.
1223 =item $h->umount ($pathordevice);
1225 This unmounts the given filesystem. The filesystem may be
1226 specified either by its mountpoint (path) or the device which
1227 contains the filesystem.
1229 =item $h->umount_all ();
1231 This unmounts all mounted filesystems.
1233 Some internal mounts are not unmounted by this call.
1235 =item $h->upload ($filename, $remotefilename);
1237 Upload local file C<filename> to C<remotefilename> on the
1240 C<filename> can also be a named pipe.
1242 See also C<$h-E<gt>download>.
1244 =item $h->vg_activate ($activate, \@volgroups);
1246 This command activates or (if C<activate> is false) deactivates
1247 all logical volumes in the listed volume groups C<volgroups>.
1248 If activated, then they are made known to the
1249 kernel, ie. they appear as C</dev/mapper> devices. If deactivated,
1250 then those devices disappear.
1252 This command is the same as running C<vgchange -a y|n volgroups...>
1254 Note that if C<volgroups> is an empty list then B<all> volume groups
1255 are activated or deactivated.
1257 =item $h->vg_activate_all ($activate);
1259 This command activates or (if C<activate> is false) deactivates
1260 all logical volumes in all volume groups.
1261 If activated, then they are made known to the
1262 kernel, ie. they appear as C</dev/mapper> devices. If deactivated,
1263 then those devices disappear.
1265 This command is the same as running C<vgchange -a y|n>
1267 =item $h->vgcreate ($volgroup, \@physvols);
1269 This creates an LVM volume group called C<volgroup>
1270 from the non-empty list of physical volumes C<physvols>.
1272 =item $h->vgremove ($vgname);
1274 Remove an LVM volume group C<vgname>, (for example C<VG>).
1276 This also forcibly removes all logical volumes in the volume
1279 =item @volgroups = $h->vgs ();
1281 List all the volumes groups detected. This is the equivalent
1282 of the L<vgs(8)> command.
1284 This returns a list of just the volume group names that were
1285 detected (eg. C<VolGroup00>).
1287 See also C<$h-E<gt>vgs_full>.
1289 =item @volgroups = $h->vgs_full ();
1291 List all the volumes groups detected. This is the equivalent
1292 of the L<vgs(8)> command. The "full" version includes all fields.
1294 =item $h->wait_ready ();
1296 Internally libguestfs is implemented by running a virtual machine
1299 You should call this after C<$h-E<gt>launch> to wait for the launch
1302 =item $h->write_file ($path, $content, $size);
1304 This call creates a file called C<path>. The contents of the
1305 file is the string C<content> (which can contain any 8 bit data),
1306 with length C<size>.
1308 As a special case, if C<size> is C<0>
1309 then the length is calculated using C<strlen> (so in this case
1310 the content cannot contain embedded ASCII NULs).
1312 I<NB.> Owing to a bug, writing content containing ASCII NUL
1313 characters does I<not> work, even if the length is specified.
1314 We hope to resolve this bug in a future version. In the meantime
1315 use C<$h-E<gt>upload>.
1317 Because of the message protocol, there is a transfer limit
1318 of somewhere between 2MB and 4MB. To transfer large files you should use
1321 =item $h->zero ($device);
1323 This command writes zeroes over the first few blocks of C<device>.
1325 How many blocks are zeroed isn't specified (but it's I<not> enough
1326 to securely wipe the device). It should be sufficient to remove
1327 any partition tables, filesystem superblocks and so on.
1329 =item $h->zerofree ($device);
1331 This runs the I<zerofree> program on C<device>. This program
1332 claims to zero unused inodes and disk blocks on an ext2/3
1333 filesystem, thus making it possible to compress the filesystem
1336 You should B<not> run this program if the filesystem is
1339 It is possible that using this program can damage the filesystem
1340 or data on the filesystem.
1350 Copyright (C) 2009 Red Hat Inc.
1354 Please see the file COPYING.LIB for the full license.
1358 L<guestfs(3)>, L<guestfish(1)>.