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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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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 =item $h->add_drive ($filename);
102 This function adds a virtual machine disk image C<filename> to the
103 guest. The first time you call this function, the disk appears as IDE
104 disk 0 (C</dev/sda>) in the guest, the second time as C</dev/sdb>, and
107 You don't necessarily need to be root when using libguestfs. However
108 you obviously do need sufficient permissions to access the filename
109 for whatever operations you want to perform (ie. read access if you
110 just want to read the image or write access if you want to modify the
113 This is equivalent to the qemu parameter C<-drive file=filename>.
115 =item $h->aug_close ();
117 Close the current Augeas handle and free up any resources
118 used by it. After calling this, you have to call
119 C<$h-E<gt>aug_init> again before you can use any other
122 =item ($nrnodes, $created) = $h->aug_defnode ($name, $expr, $val);
124 Defines a variable C<name> whose value is the result of
127 If C<expr> evaluates to an empty nodeset, a node is created,
128 equivalent to calling C<$h-E<gt>aug_set> C<expr>, C<value>.
129 C<name> will be the nodeset containing that single node.
131 On success this returns a pair containing the
132 number of nodes in the nodeset, and a boolean flag
133 if a node was created.
135 =item $nrnodes = $h->aug_defvar ($name, $expr);
137 Defines an Augeas variable C<name> whose value is the result
138 of evaluating C<expr>. If C<expr> is NULL, then C<name> is
141 On success this returns the number of nodes in C<expr>, or
142 C<0> if C<expr> evaluates to something which is not a nodeset.
144 =item $val = $h->aug_get ($path);
146 Look up the value associated with C<path>. If C<path>
147 matches exactly one node, the C<value> is returned.
149 =item $h->aug_init ($root, $flags);
151 Create a new Augeas handle for editing configuration files.
152 If there was any previous Augeas handle associated with this
153 guestfs session, then it is closed.
155 You must call this before using any other C<$h-E<gt>aug_*>
158 C<root> is the filesystem root. C<root> must not be NULL,
161 The flags are the same as the flags defined in
162 E<lt>augeas.hE<gt>, the logical I<or> of the following
167 =item C<AUG_SAVE_BACKUP> = 1
169 Keep the original file with a C<.augsave> extension.
171 =item C<AUG_SAVE_NEWFILE> = 2
173 Save changes into a file with extension C<.augnew>, and
174 do not overwrite original. Overrides C<AUG_SAVE_BACKUP>.
176 =item C<AUG_TYPE_CHECK> = 4
178 Typecheck lenses (can be expensive).
180 =item C<AUG_NO_STDINC> = 8
182 Do not use standard load path for modules.
184 =item C<AUG_SAVE_NOOP> = 16
186 Make save a no-op, just record what would have been changed.
188 =item C<AUG_NO_LOAD> = 32
190 Do not load the tree in C<$h-E<gt>aug_init>.
194 To close the handle, you can call C<$h-E<gt>aug_close>.
196 To find out more about Augeas, see L<http://augeas.net/>.
198 =item $h->aug_insert ($path, $label, $before);
200 Create a new sibling C<label> for C<path>, inserting it into
201 the tree before or after C<path> (depending on the boolean
204 C<path> must match exactly one existing node in the tree, and
205 C<label> must be a label, ie. not contain C</>, C<*> or end
206 with a bracketed index C<[N]>.
208 =item $h->aug_load ();
210 Load files into the tree.
212 See C<aug_load> in the Augeas documentation for the full gory
215 =item @matches = $h->aug_ls ($path);
217 This is just a shortcut for listing C<$h-E<gt>aug_match>
218 C<path/*> and sorting the resulting nodes into alphabetical order.
220 =item @matches = $h->aug_match ($path);
222 Returns a list of paths which match the path expression C<path>.
223 The returned paths are sufficiently qualified so that they match
224 exactly one node in the current tree.
226 =item $h->aug_mv ($src, $dest);
228 Move the node C<src> to C<dest>. C<src> must match exactly
229 one node. C<dest> is overwritten if it exists.
231 =item $nrnodes = $h->aug_rm ($path);
233 Remove C<path> and all of its children.
235 On success this returns the number of entries which were removed.
237 =item $h->aug_save ();
239 This writes all pending changes to disk.
241 The flags which were passed to C<$h-E<gt>aug_init> affect exactly
244 =item $h->aug_set ($path, $val);
246 Set the value associated with C<path> to C<value>.
248 =item $h->blockdev_flushbufs ($device);
250 This tells the kernel to flush internal buffers associated
253 This uses the L<blockdev(8)> command.
255 =item $blocksize = $h->blockdev_getbsz ($device);
257 This returns the block size of a device.
259 (Note this is different from both I<size in blocks> and
260 I<filesystem block size>).
262 This uses the L<blockdev(8)> command.
264 =item $ro = $h->blockdev_getro ($device);
266 Returns a boolean indicating if the block device is read-only
267 (true if read-only, false if not).
269 This uses the L<blockdev(8)> command.
271 =item $sizeinbytes = $h->blockdev_getsize64 ($device);
273 This returns the size of the device in bytes.
275 See also C<$h-E<gt>blockdev_getsz>.
277 This uses the L<blockdev(8)> command.
279 =item $sectorsize = $h->blockdev_getss ($device);
281 This returns the size of sectors on a block device.
282 Usually 512, but can be larger for modern devices.
284 (Note, this is not the size in sectors, use C<$h-E<gt>blockdev_getsz>
287 This uses the L<blockdev(8)> command.
289 =item $sizeinsectors = $h->blockdev_getsz ($device);
291 This returns the size of the device in units of 512-byte sectors
292 (even if the sectorsize isn't 512 bytes ... weird).
294 See also C<$h-E<gt>blockdev_getss> for the real sector size of
295 the device, and C<$h-E<gt>blockdev_getsize64> for the more
296 useful I<size in bytes>.
298 This uses the L<blockdev(8)> command.
300 =item $h->blockdev_rereadpt ($device);
302 Reread the partition table on C<device>.
304 This uses the L<blockdev(8)> command.
306 =item $h->blockdev_setbsz ($device, $blocksize);
308 This sets the block size of a device.
310 (Note this is different from both I<size in blocks> and
311 I<filesystem block size>).
313 This uses the L<blockdev(8)> command.
315 =item $h->blockdev_setro ($device);
317 Sets the block device named C<device> to read-only.
319 This uses the L<blockdev(8)> command.
321 =item $h->blockdev_setrw ($device);
323 Sets the block device named C<device> to read-write.
325 This uses the L<blockdev(8)> command.
327 =item $content = $h->cat ($path);
329 Return the contents of the file named C<path>.
331 Note that this function cannot correctly handle binary files
332 (specifically, files containing C<\0> character which is treated
333 as end of string). For those you need to use the C<$h-E<gt>download>
334 function which has a more complex interface.
336 Because of the message protocol, there is a transfer limit
337 of somewhere between 2MB and 4MB. To transfer large files you should use
340 =item $checksum = $h->checksum ($csumtype, $path);
342 This call computes the MD5, SHAx or CRC checksum of the
345 The type of checksum to compute is given by the C<csumtype>
346 parameter which must have one of the following values:
352 Compute the cyclic redundancy check (CRC) specified by POSIX
353 for the C<cksum> command.
357 Compute the MD5 hash (using the C<md5sum> program).
361 Compute the SHA1 hash (using the C<sha1sum> program).
365 Compute the SHA224 hash (using the C<sha224sum> program).
369 Compute the SHA256 hash (using the C<sha256sum> program).
373 Compute the SHA384 hash (using the C<sha384sum> program).
377 Compute the SHA512 hash (using the C<sha512sum> program).
381 The checksum is returned as a printable string.
383 =item $h->chmod ($mode, $path);
385 Change the mode (permissions) of C<path> to C<mode>. Only
386 numeric modes are supported.
388 =item $h->chown ($owner, $group, $path);
390 Change the file owner to C<owner> and group to C<group>.
392 Only numeric uid and gid are supported. If you want to use
393 names, you will need to locate and parse the password file
394 yourself (Augeas support makes this relatively easy).
396 =item $output = $h->command (\@arguments);
398 This call runs a command from the guest filesystem. The
399 filesystem must be mounted, and must contain a compatible
400 operating system (ie. something Linux, with the same
401 or compatible processor architecture).
403 The single parameter is an argv-style list of arguments.
404 The first element is the name of the program to run.
405 Subsequent elements are parameters. The list must be
406 non-empty (ie. must contain a program name).
408 The return value is anything printed to I<stdout> by
411 If the command returns a non-zero exit status, then
412 this function returns an error message. The error message
413 string is the content of I<stderr> from the command.
415 The C<$PATH> environment variable will contain at least
416 C</usr/bin> and C</bin>. If you require a program from
417 another location, you should provide the full path in the
420 Shared libraries and data files required by the program
421 must be available on filesystems which are mounted in the
422 correct places. It is the caller's responsibility to ensure
423 all filesystems that are needed are mounted at the right
426 Because of the message protocol, there is a transfer limit
427 of somewhere between 2MB and 4MB. To transfer large files you should use
430 =item @lines = $h->command_lines (\@arguments);
432 This is the same as C<$h-E<gt>command>, but splits the
433 result into a list of lines.
435 Because of the message protocol, there is a transfer limit
436 of somewhere between 2MB and 4MB. To transfer large files you should use
439 =item $h->config ($qemuparam, $qemuvalue);
441 This can be used to add arbitrary qemu command line parameters
442 of the form C<-param value>. Actually it's not quite arbitrary - we
443 prevent you from setting some parameters which would interfere with
444 parameters that we use.
446 The first character of C<param> string must be a C<-> (dash).
448 C<value> can be NULL.
450 =item $h->cp ($src, $dest);
452 This copies a file from C<src> to C<dest> where C<dest> is
453 either a destination filename or destination directory.
455 =item $h->cp_a ($src, $dest);
457 This copies a file or directory from C<src> to C<dest>
458 recursively using the C<cp -a> command.
460 =item $result = $h->debug ($subcmd, \@extraargs);
462 The C<$h-E<gt>debug> command exposes some internals of
463 C<guestfsd> (the guestfs daemon) that runs inside the
466 There is no comprehensive help for this command. You have
467 to look at the file C<daemon/debug.c> in the libguestfs source
468 to find out what you can do.
470 =item $kmsgs = $h->dmesg ();
472 This returns the kernel messages (C<dmesg> output) from
473 the guest kernel. This is sometimes useful for extended
474 debugging of problems.
476 Another way to get the same information is to enable
477 verbose messages with C<$h-E<gt>set_verbose> or by setting
478 the environment variable C<LIBGUESTFS_DEBUG=1> before
481 =item $h->download ($remotefilename, $filename);
483 Download file C<remotefilename> and save it as C<filename>
484 on the local machine.
486 C<filename> can also be a named pipe.
488 See also C<$h-E<gt>upload>, C<$h-E<gt>cat>.
490 =item $h->drop_caches ($whattodrop);
492 This instructs the guest kernel to drop its page cache,
493 and/or dentries and inode caches. The parameter C<whattodrop>
494 tells the kernel what precisely to drop, see
495 L<http://linux-mm.org/Drop_Caches>
497 Setting C<whattodrop> to 3 should drop everything.
499 This automatically calls L<sync(2)> before the operation,
500 so that the maximum guest memory is freed.
502 =item $h->end_busy ();
504 This sets the state to C<READY>, or if in C<CONFIG> then it leaves the
505 state as is. This is only used when implementing
506 actions using the low-level API.
508 For more information on states, see L<guestfs(3)>.
510 =item $equality = $h->equal ($file1, $file2);
512 This compares the two files C<file1> and C<file2> and returns
513 true if their content is exactly equal, or false otherwise.
515 The external L<cmp(1)> program is used for the comparison.
517 =item $existsflag = $h->exists ($path);
519 This returns C<true> if and only if there is a file, directory
520 (or anything) with the given C<path> name.
522 See also C<$h-E<gt>is_file>, C<$h-E<gt>is_dir>, C<$h-E<gt>stat>.
524 =item $description = $h->file ($path);
526 This call uses the standard L<file(1)> command to determine
527 the type or contents of the file. This also works on devices,
528 for example to find out whether a partition contains a filesystem.
530 The exact command which runs is C<file -bsL path>. Note in
531 particular that the filename is not prepended to the output
534 =item $status = $h->fsck ($fstype, $device);
536 This runs the filesystem checker (fsck) on C<device> which
537 should have filesystem type C<fstype>.
539 The returned integer is the status. See L<fsck(8)> for the
540 list of status codes from C<fsck>.
548 Multiple status codes can be summed together.
552 A non-zero return code can mean "success", for example if
553 errors have been corrected on the filesystem.
557 Checking or repairing NTFS volumes is not supported
562 This command is entirely equivalent to running C<fsck -a -t fstype device>.
564 =item $autosync = $h->get_autosync ();
566 Get the autosync flag.
568 =item $label = $h->get_e2label ($device);
570 This returns the ext2/3/4 filesystem label of the filesystem on
573 =item $uuid = $h->get_e2uuid ($device);
575 This returns the ext2/3/4 filesystem UUID of the filesystem on
578 =item $path = $h->get_path ();
580 Return the current search path.
582 This is always non-NULL. If it wasn't set already, then this will
583 return the default path.
585 =item $qemu = $h->get_qemu ();
587 Return the current qemu binary.
589 This is always non-NULL. If it wasn't set already, then this will
590 return the default qemu binary name.
592 =item $state = $h->get_state ();
594 This returns the current state as an opaque integer. This is
595 only useful for printing debug and internal error messages.
597 For more information on states, see L<guestfs(3)>.
599 =item $verbose = $h->get_verbose ();
601 This returns the verbose messages flag.
603 =item $h->grub_install ($root, $device);
605 This command installs GRUB (the Grand Unified Bootloader) on
606 C<device>, with the root directory being C<root>.
608 =item $dump = $h->hexdump ($path);
610 This runs C<hexdump -C> on the given C<path>. The result is
611 the human-readable, canonical hex dump of the file.
613 Because of the message protocol, there is a transfer limit
614 of somewhere between 2MB and 4MB. To transfer large files you should use
617 =item $busy = $h->is_busy ();
619 This returns true iff this handle is busy processing a command
620 (in the C<BUSY> state).
622 For more information on states, see L<guestfs(3)>.
624 =item $config = $h->is_config ();
626 This returns true iff this handle is being configured
627 (in the C<CONFIG> state).
629 For more information on states, see L<guestfs(3)>.
631 =item $dirflag = $h->is_dir ($path);
633 This returns C<true> if and only if there is a directory
634 with the given C<path> name. Note that it returns false for
635 other objects like files.
637 See also C<$h-E<gt>stat>.
639 =item $fileflag = $h->is_file ($path);
641 This returns C<true> if and only if there is a file
642 with the given C<path> name. Note that it returns false for
643 other objects like directories.
645 See also C<$h-E<gt>stat>.
647 =item $launching = $h->is_launching ();
649 This returns true iff this handle is launching the subprocess
650 (in the C<LAUNCHING> state).
652 For more information on states, see L<guestfs(3)>.
654 =item $ready = $h->is_ready ();
656 This returns true iff this handle is ready to accept commands
657 (in the C<READY> state).
659 For more information on states, see L<guestfs(3)>.
661 =item $h->kill_subprocess ();
663 This kills the qemu subprocess. You should never need to call this.
667 Internally libguestfs is implemented by running a virtual machine
670 You should call this after configuring the handle
671 (eg. adding drives) but before performing any actions.
673 =item @devices = $h->list_devices ();
675 List all the block devices.
677 The full block device names are returned, eg. C</dev/sda>
679 =item @partitions = $h->list_partitions ();
681 List all the partitions detected on all block devices.
683 The full partition device names are returned, eg. C</dev/sda1>
685 This does not return logical volumes. For that you will need to
688 =item $listing = $h->ll ($directory);
690 List the files in C<directory> (relative to the root directory,
691 there is no cwd) in the format of 'ls -la'.
693 This command is mostly useful for interactive sessions. It
694 is I<not> intended that you try to parse the output string.
696 =item @listing = $h->ls ($directory);
698 List the files in C<directory> (relative to the root directory,
699 there is no cwd). The '.' and '..' entries are not returned, but
700 hidden files are shown.
702 This command is mostly useful for interactive sessions. Programs
703 should probably use C<$h-E<gt>readdir> instead.
705 =item %statbuf = $h->lstat ($path);
707 Returns file information for the given C<path>.
709 This is the same as C<$h-E<gt>stat> except that if C<path>
710 is a symbolic link, then the link is stat-ed, not the file it
713 This is the same as the C<lstat(2)> system call.
715 =item $h->lvcreate ($logvol, $volgroup, $mbytes);
717 This creates an LVM volume group called C<logvol>
718 on the volume group C<volgroup>, with C<size> megabytes.
720 =item $h->lvm_remove_all ();
722 This command removes all LVM logical volumes, volume groups
723 and physical volumes.
725 B<This command is dangerous. Without careful use you
726 can easily destroy all your data>.
728 =item $h->lvremove ($device);
730 Remove an LVM logical volume C<device>, where C<device> is
731 the path to the LV, such as C</dev/VG/LV>.
733 You can also remove all LVs in a volume group by specifying
734 the VG name, C</dev/VG>.
736 =item @logvols = $h->lvs ();
738 List all the logical volumes detected. This is the equivalent
739 of the L<lvs(8)> command.
741 This returns a list of the logical volume device names
742 (eg. C</dev/VolGroup00/LogVol00>).
744 See also C<$h-E<gt>lvs_full>.
746 =item @logvols = $h->lvs_full ();
748 List all the logical volumes detected. This is the equivalent
749 of the L<lvs(8)> command. The "full" version includes all fields.
751 =item $h->mkdir ($path);
753 Create a directory named C<path>.
755 =item $h->mkdir_p ($path);
757 Create a directory named C<path>, creating any parent directories
758 as necessary. This is like the C<mkdir -p> shell command.
760 =item $h->mkfs ($fstype, $device);
762 This creates a filesystem on C<device> (usually a partition
763 or LVM logical volume). The filesystem type is C<fstype>, for
766 =item $h->mount ($device, $mountpoint);
768 Mount a guest disk at a position in the filesystem. Block devices
769 are named C</dev/sda>, C</dev/sdb> and so on, as they were added to
770 the guest. If those block devices contain partitions, they will have
771 the usual names (eg. C</dev/sda1>). Also LVM C</dev/VG/LV>-style
774 The rules are the same as for L<mount(2)>: A filesystem must
775 first be mounted on C</> before others can be mounted. Other
776 filesystems can only be mounted on directories which already
779 The mounted filesystem is writable, if we have sufficient permissions
780 on the underlying device.
782 The filesystem options C<sync> and C<noatime> are set with this
783 call, in order to improve reliability.
785 =item $h->mount_options ($options, $device, $mountpoint);
787 This is the same as the C<$h-E<gt>mount> command, but it
788 allows you to set the mount options as for the
789 L<mount(8)> I<-o> flag.
791 =item $h->mount_ro ($device, $mountpoint);
793 This is the same as the C<$h-E<gt>mount> command, but it
794 mounts the filesystem with the read-only (I<-o ro>) flag.
796 =item $h->mount_vfs ($options, $vfstype, $device, $mountpoint);
798 This is the same as the C<$h-E<gt>mount> command, but it
799 allows you to set both the mount options and the vfstype
800 as for the L<mount(8)> I<-o> and I<-t> flags.
802 =item @devices = $h->mounts ();
804 This returns the list of currently mounted filesystems. It returns
805 the list of devices (eg. C</dev/sda1>, C</dev/VG/LV>).
807 Some internal mounts are not shown.
809 =item $h->mv ($src, $dest);
811 This moves a file from C<src> to C<dest> where C<dest> is
812 either a destination filename or destination directory.
814 =item $h->ping_daemon ();
816 This is a test probe into the guestfs daemon running inside
817 the qemu subprocess. Calling this function checks that the
818 daemon responds to the ping message, without affecting the daemon
819 or attached block device(s) in any other way.
821 =item $h->pvcreate ($device);
823 This creates an LVM physical volume on the named C<device>,
824 where C<device> should usually be a partition name such
827 =item $h->pvremove ($device);
829 This wipes a physical volume C<device> so that LVM will no longer
832 The implementation uses the C<pvremove> command which refuses to
833 wipe physical volumes that contain any volume groups, so you have
834 to remove those first.
836 =item @physvols = $h->pvs ();
838 List all the physical volumes detected. This is the equivalent
839 of the L<pvs(8)> command.
841 This returns a list of just the device names that contain
842 PVs (eg. C</dev/sda2>).
844 See also C<$h-E<gt>pvs_full>.
846 =item @physvols = $h->pvs_full ();
848 List all the physical volumes detected. This is the equivalent
849 of the L<pvs(8)> command. The "full" version includes all fields.
851 =item @lines = $h->read_lines ($path);
853 Return the contents of the file named C<path>.
855 The file contents are returned as a list of lines. Trailing
856 C<LF> and C<CRLF> character sequences are I<not> returned.
858 Note that this function cannot correctly handle binary files
859 (specifically, files containing C<\0> character which is treated
860 as end of line). For those you need to use the C<$h-E<gt>read_file>
861 function which has a more complex interface.
863 =item $h->rm ($path);
865 Remove the single file C<path>.
867 =item $h->rm_rf ($path);
869 Remove the file or directory C<path>, recursively removing the
870 contents if its a directory. This is like the C<rm -rf> shell
873 =item $h->rmdir ($path);
875 Remove the single directory C<path>.
877 =item $h->set_autosync ($autosync);
879 If C<autosync> is true, this enables autosync. Libguestfs will make a
880 best effort attempt to run C<$h-E<gt>umount_all> followed by
881 C<$h-E<gt>sync> when the handle is closed
882 (also if the program exits without closing handles).
884 This is disabled by default (except in guestfish where it is
887 =item $h->set_busy ();
889 This sets the state to C<BUSY>. This is only used when implementing
890 actions using the low-level API.
892 For more information on states, see L<guestfs(3)>.
894 =item $h->set_e2label ($device, $label);
896 This sets the ext2/3/4 filesystem label of the filesystem on
897 C<device> to C<label>. Filesystem labels are limited to
900 You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2label>
901 to return the existing label on a filesystem.
903 =item $h->set_e2uuid ($device, $uuid);
905 This sets the ext2/3/4 filesystem UUID of the filesystem on
906 C<device> to C<uuid>. The format of the UUID and alternatives
907 such as C<clear>, C<random> and C<time> are described in the
908 L<tune2fs(8)> manpage.
910 You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2uuid>
911 to return the existing UUID of a filesystem.
913 =item $h->set_path ($path);
915 Set the path that libguestfs searches for kernel and initrd.img.
917 The default is C<$libdir/guestfs> unless overridden by setting
918 C<LIBGUESTFS_PATH> environment variable.
920 The string C<path> is stashed in the libguestfs handle, so the caller
921 must make sure it remains valid for the lifetime of the handle.
923 Setting C<path> to C<NULL> restores the default path.
925 =item $h->set_qemu ($qemu);
927 Set the qemu binary that we will use.
929 The default is chosen when the library was compiled by the
932 You can also override this by setting the C<LIBGUESTFS_QEMU>
933 environment variable.
935 The string C<qemu> is stashed in the libguestfs handle, so the caller
936 must make sure it remains valid for the lifetime of the handle.
938 Setting C<qemu> to C<NULL> restores the default qemu binary.
940 =item $h->set_ready ();
942 This sets the state to C<READY>. This is only used when implementing
943 actions using the low-level API.
945 For more information on states, see L<guestfs(3)>.
947 =item $h->set_verbose ($verbose);
949 If C<verbose> is true, this turns on verbose messages (to C<stderr>).
951 Verbose messages are disabled unless the environment variable
952 C<LIBGUESTFS_DEBUG> is defined and set to C<1>.
954 =item $h->sfdisk ($device, $cyls, $heads, $sectors, \@lines);
956 This is a direct interface to the L<sfdisk(8)> program for creating
957 partitions on block devices.
959 C<device> should be a block device, for example C</dev/sda>.
961 C<cyls>, C<heads> and C<sectors> are the number of cylinders, heads
962 and sectors on the device, which are passed directly to sfdisk as
963 the I<-C>, I<-H> and I<-S> parameters. If you pass C<0> for any
964 of these, then the corresponding parameter is omitted. Usually for
965 'large' disks, you can just pass C<0> for these, but for small
966 (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work
967 out the right geometry and you will need to tell it.
969 C<lines> is a list of lines that we feed to C<sfdisk>. For more
970 information refer to the L<sfdisk(8)> manpage.
972 To create a single partition occupying the whole disk, you would
973 pass C<lines> as a single element list, when the single element being
974 the string C<,> (comma).
976 B<This command is dangerous. Without careful use you
977 can easily destroy all your data>.
979 =item %statbuf = $h->stat ($path);
981 Returns file information for the given C<path>.
983 This is the same as the C<stat(2)> system call.
985 =item %statbuf = $h->statvfs ($path);
987 Returns file system statistics for any mounted file system.
988 C<path> should be a file or directory in the mounted file system
989 (typically it is the mount point itself, but it doesn't need to be).
991 This is the same as the C<statvfs(2)> system call.
993 =item @stringsout = $h->strings ($path);
995 This runs the L<strings(1)> command on a file and returns
996 the list of printable strings found.
998 Because of the message protocol, there is a transfer limit
999 of somewhere between 2MB and 4MB. To transfer large files you should use
1002 =item @stringsout = $h->strings_e ($encoding, $path);
1004 This is like the C<$h-E<gt>strings> command, but allows you to
1005 specify the encoding.
1007 See the L<strings(1)> manpage for the full list of encodings.
1009 Commonly useful encodings are C<l> (lower case L) which will
1010 show strings inside Windows/x86 files.
1012 The returned strings are transcoded to UTF-8.
1014 Because of the message protocol, there is a transfer limit
1015 of somewhere between 2MB and 4MB. To transfer large files you should use
1020 This syncs the disk, so that any writes are flushed through to the
1021 underlying disk image.
1023 You should always call this if you have modified a disk image, before
1026 =item $h->tar_in ($tarfile, $directory);
1028 This command uploads and unpacks local file C<tarfile> (an
1029 I<uncompressed> tar file) into C<directory>.
1031 To upload a compressed tarball, use C<$h-E<gt>tgz_in>.
1033 =item $h->tar_out ($directory, $tarfile);
1035 This command packs the contents of C<directory> and downloads
1036 it to local file C<tarfile>.
1038 To download a compressed tarball, use C<$h-E<gt>tgz_out>.
1040 =item $h->tgz_in ($tarball, $directory);
1042 This command uploads and unpacks local file C<tarball> (a
1043 I<gzip compressed> tar file) into C<directory>.
1045 To upload an uncompressed tarball, use C<$h-E<gt>tar_in>.
1047 =item $h->tgz_out ($directory, $tarball);
1049 This command packs the contents of C<directory> and downloads
1050 it to local file C<tarball>.
1052 To download an uncompressed tarball, use C<$h-E<gt>tar_out>.
1054 =item $h->touch ($path);
1056 Touch acts like the L<touch(1)> command. It can be used to
1057 update the timestamps on a file, or, if the file does not exist,
1058 to create a new zero-length file.
1060 =item %superblock = $h->tune2fs_l ($device);
1062 This returns the contents of the ext2, ext3 or ext4 filesystem
1063 superblock on C<device>.
1065 It is the same as running C<tune2fs -l device>. See L<tune2fs(8)>
1066 manpage for more details. The list of fields returned isn't
1067 clearly defined, and depends on both the version of C<tune2fs>
1068 that libguestfs was built against, and the filesystem itself.
1070 =item $h->umount ($pathordevice);
1072 This unmounts the given filesystem. The filesystem may be
1073 specified either by its mountpoint (path) or the device which
1074 contains the filesystem.
1076 =item $h->umount_all ();
1078 This unmounts all mounted filesystems.
1080 Some internal mounts are not unmounted by this call.
1082 =item $h->upload ($filename, $remotefilename);
1084 Upload local file C<filename> to C<remotefilename> on the
1087 C<filename> can also be a named pipe.
1089 See also C<$h-E<gt>download>.
1091 =item $h->vgcreate ($volgroup, \@physvols);
1093 This creates an LVM volume group called C<volgroup>
1094 from the non-empty list of physical volumes C<physvols>.
1096 =item $h->vgremove ($vgname);
1098 Remove an LVM volume group C<vgname>, (for example C<VG>).
1100 This also forcibly removes all logical volumes in the volume
1103 =item @volgroups = $h->vgs ();
1105 List all the volumes groups detected. This is the equivalent
1106 of the L<vgs(8)> command.
1108 This returns a list of just the volume group names that were
1109 detected (eg. C<VolGroup00>).
1111 See also C<$h-E<gt>vgs_full>.
1113 =item @volgroups = $h->vgs_full ();
1115 List all the volumes groups detected. This is the equivalent
1116 of the L<vgs(8)> command. The "full" version includes all fields.
1118 =item $h->wait_ready ();
1120 Internally libguestfs is implemented by running a virtual machine
1123 You should call this after C<$h-E<gt>launch> to wait for the launch
1126 =item $h->write_file ($path, $content, $size);
1128 This call creates a file called C<path>. The contents of the
1129 file is the string C<content> (which can contain any 8 bit data),
1130 with length C<size>.
1132 As a special case, if C<size> is C<0>
1133 then the length is calculated using C<strlen> (so in this case
1134 the content cannot contain embedded ASCII NULs).
1136 I<NB.> Owing to a bug, writing content containing ASCII NUL
1137 characters does I<not> work, even if the length is specified.
1138 We hope to resolve this bug in a future version. In the meantime
1139 use C<$h-E<gt>upload>.
1141 Because of the message protocol, there is a transfer limit
1142 of somewhere between 2MB and 4MB. To transfer large files you should use
1145 =item $h->zero ($device);
1147 This command writes zeroes over the first few blocks of C<device>.
1149 How many blocks are zeroed isn't specified (but it's I<not> enough
1150 to securely wipe the device). It should be sufficient to remove
1151 any partition tables, filesystem superblocks and so on.
1161 Copyright (C) 2009 Red Hat Inc.
1165 Please see the file COPYING.LIB for the full license.
1169 L<guestfs(3)>, L<guestfish(1)>.