Subsequent elements are parameters. The list must be
non-empty (ie. must contain a program name).
+The return value is anything printed to I<stdout> by
+the command.
+
+If the command returns a non-zero exit status, then
+this function returns an error message. The error message
+string is the content of I<stderr> from the command.
+
The C<$PATH> environment variable will contain at least
C</usr/bin> and C</bin>. If you require a program from
another location, you should provide the full path in the
all filesystems that are needed are mounted at the right
locations.
+Because of the message protocol, there is a transfer limit
+of somewhere between 2MB and 4MB. To transfer large files you should use
+FTP.
+
=item @lines = $h->command_lines (\@arguments);
This is the same as C<$h-E<gt>command>, but splits the
result into a list of lines.
+Because of the message protocol, there is a transfer limit
+of somewhere between 2MB and 4MB. To transfer large files you should use
+FTP.
+
=item $h->config ($qemuparam, $qemuvalue);
This can be used to add arbitrary qemu command line parameters
C<value> can be NULL.
+=item $h->cp ($src, $dest);
+
+This copies a file from C<src> to C<dest> where C<dest> is
+either a destination filename or destination directory.
+
+=item $h->cp_a ($src, $dest);
+
+This copies a file or directory from C<src> to C<dest>
+recursively using the C<cp -a> command.
+
+=item $result = $h->debug ($subcmd, \@extraargs);
+
+The C<$h-E<gt>debug> command exposes some internals of
+C<guestfsd> (the guestfs daemon) that runs inside the
+qemu subprocess.
+
+There is no comprehensive help for this command. You have
+to look at the file C<daemon/debug.c> in the libguestfs source
+to find out what you can do.
+
+=item $kmsgs = $h->dmesg ();
+
+This returns the kernel messages (C<dmesg> output) from
+the guest kernel. This is sometimes useful for extended
+debugging of problems.
+
+Another way to get the same information is to enable
+verbose messages with C<$h-E<gt>set_verbose> or by setting
+the environment variable C<LIBGUESTFS_DEBUG=1> before
+running the program.
+
=item $h->download ($remotefilename, $filename);
Download file C<remotefilename> and save it as C<filename>
See also C<$h-E<gt>upload>, C<$h-E<gt>cat>.
+=item $h->drop_caches ($whattodrop);
+
+This instructs the guest kernel to drop its page cache,
+and/or dentries and inode caches. The parameter C<whattodrop>
+tells the kernel what precisely to drop, see
+L<http://linux-mm.org/Drop_Caches>
+
+Setting C<whattodrop> to 3 should drop everything.
+
+This automatically calls L<sync(2)> before the operation,
+so that the maximum guest memory is freed.
+
+=item $h->end_busy ();
+
+This sets the state to C<READY>, or if in C<CONFIG> then it leaves the
+state as is. This is only used when implementing
+actions using the low-level API.
+
+For more information on states, see L<guestfs(3)>.
+
+=item $equality = $h->equal ($file1, $file2);
+
+This compares the two files C<file1> and C<file2> and returns
+true if their content is exactly equal, or false otherwise.
+
+The external L<cmp(1)> program is used for the comparison.
+
=item $existsflag = $h->exists ($path);
This returns C<true> if and only if there is a file, directory
particular that the filename is not prepended to the output
(the C<-b> option).
+=item $status = $h->fsck ($fstype, $device);
+
+This runs the filesystem checker (fsck) on C<device> which
+should have filesystem type C<fstype>.
+
+The returned integer is the status. See L<fsck(8)> for the
+list of status codes from C<fsck>.
+
+Notes:
+
+=over 4
+
+=item *
+
+Multiple status codes can be summed together.
+
+=item *
+
+A non-zero return code can mean "success", for example if
+errors have been corrected on the filesystem.
+
+=item *
+
+Checking or repairing NTFS volumes is not supported
+(by linux-ntfs).
+
+=back
+
+This command is entirely equivalent to running C<fsck -a -t fstype device>.
+
+=item $append = $h->get_append ();
+
+Return the additional kernel options which are added to the
+guest kernel command line.
+
+If C<NULL> then no options are added.
+
=item $autosync = $h->get_autosync ();
Get the autosync flag.
+=item $label = $h->get_e2label ($device);
+
+This returns the ext2/3/4 filesystem label of the filesystem on
+C<device>.
+
+=item $uuid = $h->get_e2uuid ($device);
+
+This returns the ext2/3/4 filesystem UUID of the filesystem on
+C<device>.
+
=item $path = $h->get_path ();
Return the current search path.
This is always non-NULL. If it wasn't set already, then this will
return the default path.
+=item $qemu = $h->get_qemu ();
+
+Return the current qemu binary.
+
+This is always non-NULL. If it wasn't set already, then this will
+return the default qemu binary name.
+
=item $state = $h->get_state ();
This returns the current state as an opaque integer. This is
This returns the verbose messages flag.
+=item $h->grub_install ($root, $device);
+
+This command installs GRUB (the Grand Unified Bootloader) on
+C<device>, with the root directory being C<root>.
+
+=item $dump = $h->hexdump ($path);
+
+This runs C<hexdump -C> on the given C<path>. The result is
+the human-readable, canonical hex dump of the file.
+
+Because of the message protocol, there is a transfer limit
+of somewhere between 2MB and 4MB. To transfer large files you should use
+FTP.
+
=item $busy = $h->is_busy ();
This returns true iff this handle is busy processing a command
B<This command is dangerous. Without careful use you
can easily destroy all your data>.
+=item $h->lvremove ($device);
+
+Remove an LVM logical volume C<device>, where C<device> is
+the path to the LV, such as C</dev/VG/LV>.
+
+You can also remove all LVs in a volume group by specifying
+the VG name, C</dev/VG>.
+
=item @logvols = $h->lvs ();
List all the logical volumes detected. This is the equivalent
=item $h->mkfs ($fstype, $device);
This creates a filesystem on C<device> (usually a partition
-of LVM logical volume). The filesystem type is C<fstype>, for
+or LVM logical volume). The filesystem type is C<fstype>, for
example C<ext3>.
=item $h->mount ($device, $mountpoint);
The filesystem options C<sync> and C<noatime> are set with this
call, in order to improve reliability.
+=item $h->mount_options ($options, $device, $mountpoint);
+
+This is the same as the C<$h-E<gt>mount> command, but it
+allows you to set the mount options as for the
+L<mount(8)> I<-o> flag.
+
+=item $h->mount_ro ($device, $mountpoint);
+
+This is the same as the C<$h-E<gt>mount> command, but it
+mounts the filesystem with the read-only (I<-o ro>) flag.
+
+=item $h->mount_vfs ($options, $vfstype, $device, $mountpoint);
+
+This is the same as the C<$h-E<gt>mount> command, but it
+allows you to set both the mount options and the vfstype
+as for the L<mount(8)> I<-o> and I<-t> flags.
+
=item @devices = $h->mounts ();
This returns the list of currently mounted filesystems. It returns
Some internal mounts are not shown.
+=item $h->mv ($src, $dest);
+
+This moves a file from C<src> to C<dest> where C<dest> is
+either a destination filename or destination directory.
+
+=item $h->ping_daemon ();
+
+This is a test probe into the guestfs daemon running inside
+the qemu subprocess. Calling this function checks that the
+daemon responds to the ping message, without affecting the daemon
+or attached block device(s) in any other way.
+
=item $h->pvcreate ($device);
This creates an LVM physical volume on the named C<device>,
where C<device> should usually be a partition name such
as C</dev/sda1>.
+=item $h->pvremove ($device);
+
+This wipes a physical volume C<device> so that LVM will no longer
+recognise it.
+
+The implementation uses the C<pvremove> command which refuses to
+wipe physical volumes that contain any volume groups, so you have
+to remove those first.
+
=item @physvols = $h->pvs ();
List all the physical volumes detected. This is the equivalent
Remove the single directory C<path>.
+=item $h->set_append ($append);
+
+This function is used to add additional options to the
+guest kernel command line.
+
+The default is C<NULL> unless overridden by setting
+C<LIBGUESTFS_APPEND> environment variable.
+
+Setting C<append> to C<NULL> means I<no> additional options
+are passed (libguestfs always adds a few of its own).
+
=item $h->set_autosync ($autosync);
If C<autosync> is true, this enables autosync. Libguestfs will make a
-best effort attempt to run C<$h-E<gt>sync> when the handle is closed
+best effort attempt to run C<$h-E<gt>umount_all> followed by
+C<$h-E<gt>sync> when the handle is closed
(also if the program exits without closing handles).
+This is disabled by default (except in guestfish where it is
+enabled by default).
+
=item $h->set_busy ();
This sets the state to C<BUSY>. This is only used when implementing
For more information on states, see L<guestfs(3)>.
+=item $h->set_e2label ($device, $label);
+
+This sets the ext2/3/4 filesystem label of the filesystem on
+C<device> to C<label>. Filesystem labels are limited to
+16 characters.
+
+You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2label>
+to return the existing label on a filesystem.
+
+=item $h->set_e2uuid ($device, $uuid);
+
+This sets the ext2/3/4 filesystem UUID of the filesystem on
+C<device> to C<uuid>. The format of the UUID and alternatives
+such as C<clear>, C<random> and C<time> are described in the
+L<tune2fs(8)> manpage.
+
+You can use either C<$h-E<gt>tune2fs_l> or C<$h-E<gt>get_e2uuid>
+to return the existing UUID of a filesystem.
+
=item $h->set_path ($path);
Set the path that libguestfs searches for kernel and initrd.img.
The default is C<$libdir/guestfs> unless overridden by setting
C<LIBGUESTFS_PATH> environment variable.
-The string C<path> is stashed in the libguestfs handle, so the caller
-must make sure it remains valid for the lifetime of the handle.
-
Setting C<path> to C<NULL> restores the default path.
+=item $h->set_qemu ($qemu);
+
+Set the qemu binary that we will use.
+
+The default is chosen when the library was compiled by the
+configure script.
+
+You can also override this by setting the C<LIBGUESTFS_QEMU>
+environment variable.
+
+Setting C<qemu> to C<NULL> restores the default qemu binary.
+
=item $h->set_ready ();
This sets the state to C<READY>. This is only used when implementing
This is the same as the C<statvfs(2)> system call.
+=item @stringsout = $h->strings ($path);
+
+This runs the L<strings(1)> command on a file and returns
+the list of printable strings found.
+
+Because of the message protocol, there is a transfer limit
+of somewhere between 2MB and 4MB. To transfer large files you should use
+FTP.
+
+=item @stringsout = $h->strings_e ($encoding, $path);
+
+This is like the C<$h-E<gt>strings> command, but allows you to
+specify the encoding.
+
+See the L<strings(1)> manpage for the full list of encodings.
+
+Commonly useful encodings are C<l> (lower case L) which will
+show strings inside Windows/x86 files.
+
+The returned strings are transcoded to UTF-8.
+
+Because of the message protocol, there is a transfer limit
+of somewhere between 2MB and 4MB. To transfer large files you should use
+FTP.
+
=item $h->sync ();
This syncs the disk, so that any writes are flushed through to the
You should always call this if you have modified a disk image, before
closing the handle.
+=item $h->tar_in ($tarfile, $directory);
+
+This command uploads and unpacks local file C<tarfile> (an
+I<uncompressed> tar file) into C<directory>.
+
+To upload a compressed tarball, use C<$h-E<gt>tgz_in>.
+
+=item $h->tar_out ($directory, $tarfile);
+
+This command packs the contents of C<directory> and downloads
+it to local file C<tarfile>.
+
+To download a compressed tarball, use C<$h-E<gt>tgz_out>.
+
+=item $h->tgz_in ($tarball, $directory);
+
+This command uploads and unpacks local file C<tarball> (a
+I<gzip compressed> tar file) into C<directory>.
+
+To upload an uncompressed tarball, use C<$h-E<gt>tar_in>.
+
+=item $h->tgz_out ($directory, $tarball);
+
+This command packs the contents of C<directory> and downloads
+it to local file C<tarball>.
+
+To download an uncompressed tarball, use C<$h-E<gt>tar_out>.
+
=item $h->touch ($path);
Touch acts like the L<touch(1)> command. It can be used to
=item %superblock = $h->tune2fs_l ($device);
-This returns the contents of the ext2 or ext3 filesystem superblock
-on C<device>.
+This returns the contents of the ext2, ext3 or ext4 filesystem
+superblock on C<device>.
It is the same as running C<tune2fs -l device>. See L<tune2fs(8)>
manpage for more details. The list of fields returned isn't
This creates an LVM volume group called C<volgroup>
from the non-empty list of physical volumes C<physvols>.
+=item $h->vgremove ($vgname);
+
+Remove an LVM volume group C<vgname>, (for example C<VG>).
+
+This also forcibly removes all logical volumes in the volume
+group (if any).
+
=item @volgroups = $h->vgs ();
List all the volumes groups detected. This is the equivalent
then the length is calculated using C<strlen> (so in this case
the content cannot contain embedded ASCII NULs).
+I<NB.> Owing to a bug, writing content containing ASCII NUL
+characters does I<not> work, even if the length is specified.
+We hope to resolve this bug in a future version. In the meantime
+use C<$h-E<gt>upload>.
+
Because of the message protocol, there is a transfer limit
of somewhere between 2MB and 4MB. To transfer large files you should use
FTP.
+=item $h->zero ($device);
+
+This command writes zeroes over the first few blocks of C<device>.
+
+How many blocks are zeroed isn't specified (but it's I<not> enough
+to securely wipe the device). It should be sufficient to remove
+any partition tables, filesystem superblocks and so on.
+
=cut
1;
git.annexia.org / libguestfs.git / blobdiff