Test the 'command' and 'command_lines' functions thoroughly.

[libguestfs.git] / perl / lib / Sys / Guestfs.pm

diff --git a/perl/lib/Sys/Guestfs.pm b/perl/lib/Sys/Guestfs.pm
index 2d75b69..001fa88 100644 (file)
--- a/perl/lib/Sys/Guestfs.pm
+++ b/perl/lib/Sys/Guestfs.pm
@@ -405,6 +405,13 @@ The first element is the name of the program to run.
 Subsequent elements are parameters.  The list must be
 non-empty (ie. must contain a program name).
 
 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<$PATH> environment variable will contain at least
 C</usr/bin> and C</bin>.  If you require a program from
 another location, you should provide the full path in the
 The C<$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


@@ -416,11 +423,19 @@ correct places.  It is the caller's responsibility to ensure
 all filesystems that are needed are mounted at the right
 locations.
 
 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.
 
 =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
 =item $h->config ($qemuparam, $qemuvalue);
 
 This can be used to add arbitrary qemu command line parameters


@@ -432,6 +447,16 @@ The first character of C<param> string must be a C<-> (dash).
 
 C<value> can be NULL.
 
 
 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
 =item $result = $h->debug ($subcmd, \@extraargs);
 
 The C<$h-E<gt>debug> command exposes some internals of


@@ -442,6 +467,17 @@ 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.
 
 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>
 =item $h->download ($remotefilename, $filename);
 
 Download file C<remotefilename> and save it as C<filename>


@@ -451,6 +487,33 @@ C<filename> can also be a named pipe.
 
 See also C<$h-E<gt>upload>, C<$h-E<gt>cat>.
 
 
 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
 =item $existsflag = $h->exists ($path);
 
 This returns C<true> if and only if there is a file, directory


@@ -474,13 +537,30 @@ 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
 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>, and note that multiple
-status codes can be summed together.
+list of status codes from C<fsck>.
+
+Notes:
+
+=over 4
+
+=item *
+
+Multiple status codes can be summed together.

 
 

-It is entirely equivalent to running C<fsck -a -t fstype device>.
-Note that checking or repairing NTFS volumes is not supported
+=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).
 
 (by linux-ntfs).
 

+=back
+
+This command is entirely equivalent to running C<fsck -a -t fstype device>.
+

 =item $autosync = $h->get_autosync ();
 
 Get the autosync flag.
 =item $autosync = $h->get_autosync ();
 
 Get the autosync flag.


@@ -520,6 +600,20 @@ For more information on states, see L<guestfs(3)>.
 
 This returns the verbose messages flag.
 
 
 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
 =item $busy = $h->is_busy ();
 
 This returns true iff this handle is busy processing a command


@@ -666,7 +760,7 @@ as necessary.  This is like the C<mkdir -p> shell command.
 =item $h->mkfs ($fstype, $device);
 
 This creates a filesystem on C<device> (usually a partition
 =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);
 example C<ext3>.
 
 =item $h->mount ($device, $mountpoint);


@@ -712,6 +806,18 @@ the list of devices (eg. C</dev/sda1>, C</dev/VG/LV>).
 
 Some internal mounts are not shown.
 
 
 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>,
 =item $h->pvcreate ($device);
 
 This creates an LVM physical volume on the named C<device>,


@@ -884,6 +990,31 @@ C<path> should be a file or directory in the mounted file system
 
 This is the same as the C<statvfs(2)> system call.
 
 
 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
 =item $h->sync ();
 
 This syncs the disk, so that any writes are flushed through to the


@@ -1002,6 +1133,11 @@ As a special case, if C<size> is C<0>
 then the length is calculated using C<strlen> (so in this case
 the content cannot contain embedded ASCII NULs).
 
 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.
 Because of the message protocol, there is a transfer limit 
 of somewhere between 2MB and 4MB.  To transfer large files you should use
 FTP.