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
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
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.
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
=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);
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>,
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
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);
You can also override this by setting the C<LIBGUESTFS_QEMU>
environment variable.
-The string C<qemu> is stashed in the libguestfs handle, so the caller
-must make sure it remains valid for the lifetime of the handle.
-
Setting C<qemu> to C<NULL> restores the default qemu binary.
=item $h->set_ready ();
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 $h->sync ();
This syncs the disk, so that any writes are flushed through to the
then the length is calculated using C<strlen> (so in this case
the content cannot contain embedded ASCII NULs).
+I<NB.> Owing to a bug, writing content containing ASCII NUL
+characters does I<not> work, even if the length is specified.
+We hope to resolve this bug in a future version. In the meantime
+use C<$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.
git.annexia.org / libguestfs.git / blobdiff