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Diffstat (limited to 'cat/virt-cat.pl')
| -rwxr-xr-x | cat/virt-cat.pl | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/cat/virt-cat.pl b/cat/virt-cat.pl new file mode 100755 index 00000000..6a502807 --- /dev/null +++ b/cat/virt-cat.pl @@ -0,0 +1,192 @@ +#!/usr/bin/perl -w +# virt-cat +# 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 Data::Dumper; +use File::Temp qw/tempdir/; +use XML::Writer; +use Locale::TextDomain 'libguestfs'; + +=encoding utf8 + +=head1 NAME + +virt-cat - Display a file in a virtual machine + +=head1 SYNOPSIS + + virt-cat [--options] domname file + + virt-cat [--options] disk.img [disk.img ...] file + +=head1 DESCRIPTION + +C<virt-cat> is a command line tool to display the contents of C<file> +where C<file> exists in the named virtual machine (or disk image). + +C<virt-cat> can be used to quickly view a single file. For more +complex cases you should look at the L<guestfish(1)> tool. + +=head1 EXAMPLES + +Display C</etc/fstab> file from inside the libvirt VM called +C<mydomain>: + + virt-cat mydomain /etc/fstab + +List syslog messages from a VM: + + virt-cat mydomain /var/log/messages | tail + +Find out what packages were recently installed: + + virt-cat mydomain /var/log/yum.log | tail + +Find out who is logged on inside a virtual machine: + + virt-cat mydomain /var/run/utmp > /tmp/utmp + who /tmp/utmp + +or who was logged on: + + virt-cat mydomain /var/log/wtmp > /tmp/wtmp + last -f /tmp/wtmp + +=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. + +=back + +=cut + +GetOptions ("help|?" => \$help, + "version" => \$version, + "connect|c=s" => \$uri, + ) 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-cat: no image, VM names or filenames to cat given") + if @ARGV <= 1; + +my $filename = pop @ARGV; + +my $g; +if ($uri) { + $g = open_guest (\@ARGV, address => $uri); +} else { + $g = open_guest (\@ARGV); +} + +$g->launch (); +$g->wait_ready (); + +# List of possible filesystems. +my @partitions = get_partitions ($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" if @roots == 0; +die __"multiboot operating systems are not supported by virt-cat" if @roots > 1; +my $root_dev = $roots[0]; + +my $os = $oses->{$root_dev}; +mount_operating_system ($g, $os); + +# Allow this to fail in case eg. the file does not exist. +# NB: https://bugzilla.redhat.com/show_bug.cgi?id=501888 +print $g->download($filename, "/dev/stdout"); + +=head1 SEE ALSO + +L<guestfs(3)>, +L<guestfish(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. |
