New tool: virt-tar

This adds a new tool call virt-tar which is a general purpose
archive and uploading tool.  It doesn't add any functionality
which wasn't previously possible using guestfish, but makes it
simpler to access for some users.

Examples:

 virt-tar -zx myguest /home home.tar.gz
 virt-tar -zu myguest uploadstuff.tar.gz /tmp

1 files changed, 288 insertions, 0 deletions

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+#!/usr/bin/perl -w
+# virt-tar
+# Copyright (C) 2009 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+use warnings;
+use strict;
+
+use Sys::Guestfs;
+use Sys::Guestfs::Lib qw(open_guest get_partitions resolve_windows_path
+  inspect_all_partitions inspect_partition
+  inspect_operating_systems mount_operating_system);
+use Pod::Usage;
+use Getopt::Long;
+use File::Temp qw/tempfile/;
+use Locale::TextDomain 'libguestfs';
+
+=encoding utf8
+
+=head1 NAME
+
+virt-tar - Extract or upload files to a virtual machine
+
+=head1 SYNOPSIS
+
+ virt-tar [--options] -x domname directory tarball
+
+ virt-tar [--options] -u domname tarball directory
+
+ virt-tar [--options] disk.img [disk.img ...] -x directory tarball
+
+ virt-tar [--options] disk.img [disk.img ...] -u tarball directory
+
+=head1 EXAMPLES
+
+Download C</home> from the VM into a local tarball:
+
+ virt-tar -x domname /home home.tar
+
+ virt-tar -zx domname /home home.tar.gz
+
+Upload a local tarball and unpack it inside C</tmp> in the VM:
+
+ virt-tar -u domname uploadstuff.tar /tmp
+
+ virt-tar -zu domname uploadstuff.tar.gz /tmp
+
+=head1 WARNING
+
+You must I<not> use C<virt-tar> with the C<-u> option (upload) on live
+virtual machines.  If you do this, you risk disk corruption in the VM.
+C<virt-tar> tries to stop you from doing this, but doesn't catch all
+cases.
+
+You can use C<-x> (extract) on live virtual machines, but you might
+get inconsistent results or errors if there is filesystem activity
+inside the VM.  If the live VM is synched and quiescent, then
+C<virt-tar> will usually work, but the only way to guarantee
+consistent results is if the virtual machine is shut down.
+
+=head1 DESCRIPTION
+
+C<virt-tar> is a general purpose archive tool for downloading and
+uploading parts of a guest filesystem.  There are many possibilities:
+making backups, uploading data files, snooping on guest activity,
+fixing or customizing guests, etc.
+
+If you want to just view a single file, use L<virt-cat(1)>.  If you
+just want to edit a single file, use L<virt-edit(1)>.  For more
+complex cases you should look at the L<guestfish(1)> tool.
+
+There are two modes of operation: C<-x> (eXtract) downloads a
+directory and its contents (recursively) from the virtual machine into
+a local tarball.  C<-u> uploads from a local tarball, unpacking it
+into a directory inside the virtual machine.  You cannot use these two
+options together.
+
+In addition, you may need to use the C<-z> (gZip) option to enable
+compression.  When uploading, you have to specify C<-z> if the upload
+file is compressed because virt-tar won't detect this on its own.
+
+C<virt-tar> can only handle tar (optionally gzipped) format tarballs.
+For example it cannot do PKZip files or bzip2 compression.  If you
+want that then you'll have to rebuild the tarballs yourself.  (This is
+a limitation of the L<libguestfs(3)> API).
+
+=head1 OPTIONS
+
+=over 4
+
+=cut
+
+my $help;
+
+=item B<--help>
+
+Display brief help.
+
+=cut
+
+my $version;
+
+=item B<--version>
+
+Display version number and exit.
+
+=cut
+
+my $uri;
+
+=item B<--connect URI> | B<-c URI>
+
+If using libvirt, connect to the given I<URI>.  If omitted, then we
+connect to the default libvirt hypervisor.
+
+If you specify guest block devices directly, then libvirt is not used
+at all.
+
+=cut
+
+my $mode;
+
+=item B<-x> | B<--extract> | B<--download>
+
+=item B<-u> | B<--upload>
+
+Use C<-x> to extract (download) a directory from a virtual machine
+to a local tarball.
+
+Use C<-u> to upload and unpack from a local tarball into a virtual
+machine.  Please read the L</WARNING> section above before using this
+option.
+
+You must specify exactly one of these options.
+
+=cut
+
+my $gzip;
+
+=item B<-z> | B<--gzip>
+
+Specify that the input or output tarball is gzip-compressed.
+
+=back
+
+=cut
+
+sub set_mode_x
+{
+    die __"virt-tar: extract/upload mode specified twice on the command line\n"
+        if $mode;
+    $mode = "x";
+}
+
+sub set_mode_u
+{
+    die __"virt-tar: extract/upload mode specified twice on the command line\n"
+        if $mode;
+    $mode = "u";
+}
+
+Getopt::Long::Configure ("bundling");
+GetOptions ("help|?" => \$help,
+            "version" => \$version,
+            "connect|c=s" => \$uri,
+            "extract|download|x" => \&set_mode_x,
+            "upload|u" => \&set_mode_u,
+            "gzip|z" => \$gzip,
+    ) or pod2usage (2);
+pod2usage (1) if $help;
+if ($version) {
+    my $g = Sys::Guestfs->new ();
+    my %h = $g->version ();
+    print "$h{major}.$h{minor}.$h{release}$h{extra}\n";
+    exit
+}
+
+pod2usage (__"virt-tar: no image, VM names, directory or filename given")
+    if @ARGV <= 2;
+
+die __"virt-tar: either -x or -u must be specified on the command line\n"
+    unless $mode;
+
+# Note: 'pop' reads arguments right to left.
+my ($tarball, $directory);
+if ($mode eq "x") {
+    $tarball = pop @ARGV;
+    $directory = pop @ARGV;
+} else { # $mode eq "u"
+    $directory = pop @ARGV;
+    $tarball = pop @ARGV;
+    die __"virt-tar: $tarball: file not found\n" unless -f $tarball;
+}
+die __"virt-tar: $directory: directory name must start with '/' character\n"
+    unless substr ($directory, 0, 1) eq "/";
+
+my @args = (\@ARGV);
+push @args, address => $uri if $uri;
+push @args, rw => 1 if $mode eq "u";
+
+my $g = open_guest (@args);
+$g->launch ();
+
+# List of possible filesystems.
+my @partitions = get_partitions ($g);
+
+# Now query each one to build up a picture of what's in it.
+my %fses =
+    inspect_all_partitions ($g, \@partitions,
+      use_windows_registry => 0);
+
+my $oses = inspect_operating_systems ($g, \%fses);
+
+my @roots = keys %$oses;
+die __"no root device found in this operating system image\n" if @roots == 0;
+die __"multiboot operating systems are not supported by virt-tar\n" if @roots > 1;
+my $root_dev = $roots[0];
+
+my $os = $oses->{$root_dev};
+mount_operating_system ($g, $os, $mode eq "u" ? 0 : 1);
+
+# Do the tar command.
+if ($mode eq "x") {
+    if ($gzip) {
+        $g->tgz_out ($directory, $tarball);
+    } else {
+        $g->tar_out ($directory, $tarball);
+    }
+} else { # mode eq "u"
+    if ($gzip) {
+        $g->tgz_in ($tarball, $directory);
+    } else {
+        $g->tar_in ($tarball, $directory);
+    }
+}
+
+$g->sync ();
+$g->umount_all ();
+
+undef $g;
+
+exit 0;
+
+=head1 SEE ALSO
+
+L<guestfs(3)>,
+L<guestfish(1)>,
+L<virt-cat(1)>,
+L<virt-edit(1)>,
+L<Sys::Guestfs(3)>,
+L<Sys::Guestfs::Lib(3)>,
+L<Sys::Virt(3)>,
+L<http://libguestfs.org/>.
+
+=head1 AUTHOR
+
+Richard W.M. Jones L<http://et.redhat.com/~rjones/>
+
+=head1 COPYRIGHT
+
+Copyright (C) 2009 Red Hat Inc.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.