Added 'zero' command to wipe partition tables and superblocks.

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

diff --git a/perl/lib/Sys/Guestfs.pm b/perl/lib/Sys/Guestfs.pm
index 9d050b4..2d75b69 100644 (file)
--- a/perl/lib/Sys/Guestfs.pm
+++ b/perl/lib/Sys/Guestfs.pm
@@ -245,19 +245,141 @@ how files are saved.
 
 Set the value associated with C<path> to C<value>.
 
 
 Set the value associated with C<path> to C<value>.
 

+=item $h->blockdev_flushbufs ($device);
+
+This tells the kernel to flush internal buffers associated
+with C<device>.
+
+This uses the L<blockdev(8)> command.
+
+=item $blocksize = $h->blockdev_getbsz ($device);
+
+This returns the block size of a device.
+
+(Note this is different from both I<size in blocks> and
+I<filesystem block size>).
+
+This uses the L<blockdev(8)> command.
+
+=item $ro = $h->blockdev_getro ($device);
+
+Returns a boolean indicating if the block device is read-only
+(true if read-only, false if not).
+
+This uses the L<blockdev(8)> command.
+
+=item $sizeinbytes = $h->blockdev_getsize64 ($device);
+
+This returns the size of the device in bytes.
+
+See also C<$h-E<gt>blockdev_getsz>.
+
+This uses the L<blockdev(8)> command.
+
+=item $sectorsize = $h->blockdev_getss ($device);
+
+This returns the size of sectors on a block device.
+Usually 512, but can be larger for modern devices.
+
+(Note, this is not the size in sectors, use C<$h-E<gt>blockdev_getsz>
+for that).
+
+This uses the L<blockdev(8)> command.
+
+=item $sizeinsectors = $h->blockdev_getsz ($device);
+
+This returns the size of the device in units of 512-byte sectors
+(even if the sectorsize isn't 512 bytes ... weird).
+
+See also C<$h-E<gt>blockdev_getss> for the real sector size of
+the device, and C<$h-E<gt>blockdev_getsize64> for the more
+useful I<size in bytes>.
+
+This uses the L<blockdev(8)> command.
+
+=item $h->blockdev_rereadpt ($device);
+
+Reread the partition table on C<device>.
+
+This uses the L<blockdev(8)> command.
+
+=item $h->blockdev_setbsz ($device, $blocksize);
+
+This sets the block size of a device.
+
+(Note this is different from both I<size in blocks> and
+I<filesystem block size>).
+
+This uses the L<blockdev(8)> command.
+
+=item $h->blockdev_setro ($device);
+
+Sets the block device named C<device> to read-only.
+
+This uses the L<blockdev(8)> command.
+
+=item $h->blockdev_setrw ($device);
+
+Sets the block device named C<device> to read-write.
+
+This uses the L<blockdev(8)> command.
+

 =item $content = $h->cat ($path);
 
 Return the contents of the file named C<path>.
 
 Note that this function cannot correctly handle binary files
 (specifically, files containing C<\0> character which is treated
 =item $content = $h->cat ($path);
 
 Return the contents of the file named C<path>.
 
 Note that this function cannot correctly handle binary files
 (specifically, files containing C<\0> character which is treated

-as end of string).  For those you need to use the C<$h-E<gt>read_file>
+as end of string).  For those you need to use the C<$h-E<gt>download>

 function which has a more complex interface.
 
 Because of the message protocol, there is a transfer limit 
 of somewhere between 2MB and 4MB.  To transfer large files you should use
 FTP.
 
 function which has a more complex interface.
 
 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 $checksum = $h->checksum ($csumtype, $path);
+
+This call computes the MD5, SHAx or CRC checksum of the
+file named C<path>.
+
+The type of checksum to compute is given by the C<csumtype>
+parameter which must have one of the following values:
+
+=over 4
+
+=item C<crc>
+
+Compute the cyclic redundancy check (CRC) specified by POSIX
+for the C<cksum> command.
+
+=item C<md5>
+
+Compute the MD5 hash (using the C<md5sum> program).
+
+=item C<sha1>
+
+Compute the SHA1 hash (using the C<sha1sum> program).
+
+=item C<sha224>
+
+Compute the SHA224 hash (using the C<sha224sum> program).
+
+=item C<sha256>
+
+Compute the SHA256 hash (using the C<sha256sum> program).
+
+=item C<sha384>
+
+Compute the SHA384 hash (using the C<sha384sum> program).
+
+=item C<sha512>
+
+Compute the SHA512 hash (using the C<sha512sum> program).
+
+=back
+
+The checksum is returned as a printable string.
+

 =item $h->chmod ($mode, $path);
 
 Change the mode (permissions) of C<path> to C<mode>.  Only
 =item $h->chmod ($mode, $path);
 
 Change the mode (permissions) of C<path> to C<mode>.  Only


@@ -271,6 +393,34 @@ Only numeric uid and gid are supported.  If you want to use
 names, you will need to locate and parse the password file
 yourself (Augeas support makes this relatively easy).
 
 names, you will need to locate and parse the password file
 yourself (Augeas support makes this relatively easy).
 

+=item $output = $h->command (\@arguments);
+
+This call runs a command from the guest filesystem.  The
+filesystem must be mounted, and must contain a compatible
+operating system (ie. something Linux, with the same
+or compatible processor architecture).
+
+The single parameter is an argv-style list of arguments.
+The first element is the name of the program to run.
+Subsequent elements are parameters.  The list must be
+non-empty (ie. must contain a program name).
+
+The C<$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
+first parameter.
+
+Shared libraries and data files required by the program
+must be available on filesystems which are mounted in the
+correct places.  It is the caller's responsibility to ensure
+all filesystems that are needed are mounted at the right
+locations.
+
+=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 $h->config ($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


@@ -282,6 +432,25 @@ The first character of C<param> string must be a C<-> (dash).
 
 C<value> can be NULL.
 
 
 C<value> can be NULL.
 

+=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 $h->download ($remotefilename, $filename);
+
+Download file C<remotefilename> and save it as C<filename>
+on the local machine.
+
+C<filename> can also be a named pipe.
+
+See also C<$h-E<gt>upload>, C<$h-E<gt>cat>.
+

 =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


@@ -299,10 +468,33 @@ The exact command which runs is C<file -bsL path>.  Note in
 particular that the filename is not prepended to the output
 (the C<-b> option).
 
 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>, and note that 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
+(by linux-ntfs).
+

 =item $autosync = $h->get_autosync ();
 
 Get the autosync flag.
 
 =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.
 =item $path = $h->get_path ();
 
 Return the current search path.


@@ -310,10 +502,38 @@ Return the current search path.
 This is always non-NULL.  If it wasn't set already, then this will
 return the default 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
+only useful for printing debug and internal error messages.
+
+For more information on states, see L<guestfs(3)>.
+

 =item $verbose = $h->get_verbose ();
 
 This returns the verbose messages flag.
 
 =item $verbose = $h->get_verbose ();
 
 This returns the verbose messages flag.
 

+=item $busy = $h->is_busy ();
+
+This returns true iff this handle is busy processing a command
+(in the C<BUSY> state).
+
+For more information on states, see L<guestfs(3)>.
+
+=item $config = $h->is_config ();
+
+This returns true iff this handle is being configured
+(in the C<CONFIG> state).
+
+For more information on states, see L<guestfs(3)>.
+

 =item $dirflag = $h->is_dir ($path);
 
 This returns C<true> if and only if there is a directory
 =item $dirflag = $h->is_dir ($path);
 
 This returns C<true> if and only if there is a directory


@@ -330,6 +550,20 @@ other objects like directories.
 
 See also C<$h-E<gt>stat>.
 
 
 See also C<$h-E<gt>stat>.
 

+=item $launching = $h->is_launching ();
+
+This returns true iff this handle is launching the subprocess
+(in the C<LAUNCHING> state).
+
+For more information on states, see L<guestfs(3)>.
+
+=item $ready = $h->is_ready ();
+
+This returns true iff this handle is ready to accept commands
+(in the C<READY> state).
+
+For more information on states, see L<guestfs(3)>.
+

 =item $h->kill_subprocess ();
 
 This kills the qemu subprocess.  You should never need to call this.
 =item $h->kill_subprocess ();
 
 This kills the qemu subprocess.  You should never need to call this.


@@ -374,6 +608,16 @@ hidden files are shown.
 This command is mostly useful for interactive sessions.  Programs
 should probably use C<$h-E<gt>readdir> instead.
 
 This command is mostly useful for interactive sessions.  Programs
 should probably use C<$h-E<gt>readdir> instead.
 

+=item %statbuf = $h->lstat ($path);
+
+Returns file information for the given C<path>.
+
+This is the same as C<$h-E<gt>stat> except that if C<path>
+is a symbolic link, then the link is stat-ed, not the file it
+refers to.
+
+This is the same as the C<lstat(2)> system call.
+

 =item $h->lvcreate ($logvol, $volgroup, $mbytes);
 
 This creates an LVM volume group called C<logvol>
 =item $h->lvcreate ($logvol, $volgroup, $mbytes);
 
 This creates an LVM volume group called C<logvol>


@@ -387,6 +631,14 @@ and physical volumes.
 B<This command is dangerous.  Without careful use you
 can easily destroy all your data>.
 
 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 @logvols = $h->lvs ();
 
 List all the logical volumes detected.  This is the equivalent


@@ -436,6 +688,23 @@ on the underlying device.
 The filesystem options C<sync> and C<noatime> are set with this
 call, in order to improve reliability.
 
 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
 =item @devices = $h->mounts ();
 
 This returns the list of currently mounted filesystems.  It returns


@@ -449,6 +718,15 @@ 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>.
 
 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
 =item @physvols = $h->pvs ();
 
 List all the physical volumes detected.  This is the equivalent


@@ -493,9 +771,39 @@ Remove the single directory C<path>.
 =item $h->set_autosync ($autosync);
 
 If C<autosync> is true, this enables autosync.  Libguestfs will make a
 =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).
 
 (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
+actions using the low-level API.
+
+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.
 =item $h->set_path ($path);
 
 Set the path that libguestfs searches for kernel and initrd.img.


@@ -508,6 +816,28 @@ must make sure it remains valid for the lifetime of the handle.
 
 Setting C<path> to C<NULL> restores the default path.
 
 
 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.
+
+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 sets the state to C<READY>.  This is only used when implementing
+actions using the low-level API.
+
+For more information on states, see L<guestfs(3)>.
+

 =item $h->set_verbose ($verbose);
 
 If C<verbose> is true, this turns on verbose messages (to C<stderr>).
 =item $h->set_verbose ($verbose);
 
 If C<verbose> is true, this turns on verbose messages (to C<stderr>).


@@ -540,6 +870,20 @@ the string C<,> (comma).
 B<This command is dangerous.  Without careful use you
 can easily destroy all your data>.
 
 B<This command is dangerous.  Without careful use you
 can easily destroy all your data>.
 

+=item %statbuf = $h->stat ($path);
+
+Returns file information for the given C<path>.
+
+This is the same as the C<stat(2)> system call.
+
+=item %statbuf = $h->statvfs ($path);
+
+Returns file system statistics for any mounted file system.
+C<path> should be a file or directory in the mounted file system
+(typically it is the mount point itself, but it doesn't need to be).
+
+This is the same as the C<statvfs(2)> system call.
+

 =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


@@ -548,12 +892,50 @@ underlying disk image.
 You should always call this if you have modified a disk image, before
 closing the handle.
 
 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
 update the timestamps on a file, or, if the file does not exist,
 to create a new zero-length file.
 
 =item $h->touch ($path);
 
 Touch acts like the L<touch(1)> command.  It can be used to
 update the timestamps on a file, or, if the file does not exist,
 to create a new zero-length file.
 

+=item %superblock = $h->tune2fs_l ($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
+clearly defined, and depends on both the version of C<tune2fs>
+that libguestfs was built against, and the filesystem itself.
+

 =item $h->umount ($pathordevice);
 
 This unmounts the given filesystem.  The filesystem may be
 =item $h->umount ($pathordevice);
 
 This unmounts the given filesystem.  The filesystem may be


@@ -566,11 +948,27 @@ This unmounts all mounted filesystems.
 
 Some internal mounts are not unmounted by this call.
 
 
 Some internal mounts are not unmounted by this call.
 

+=item $h->upload ($filename, $remotefilename);
+
+Upload local file C<filename> to C<remotefilename> on the
+filesystem.
+
+C<filename> can also be a named pipe.
+
+See also C<$h-E<gt>download>.
+

 =item $h->vgcreate ($volgroup, \@physvols);
 
 This creates an LVM volume group called C<volgroup>
 from the non-empty list of physical volumes C<physvols>.
 
 =item $h->vgcreate ($volgroup, \@physvols);
 
 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
 =item @volgroups = $h->vgs ();
 
 List all the volumes groups detected.  This is the equivalent


@@ -608,6 +1006,14 @@ Because of the message protocol, there is a transfer limit
 of somewhere between 2MB and 4MB.  To transfer large files you should use
 FTP.
 
 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;
 =cut
 
 1;