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#!/usr/bin/perl -w
# virt-rescue
# 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);
use Pod::Usage;
use Getopt::Long;
use Locale::TextDomain 'libguestfs';
=encoding utf8
=head1 NAME
virt-rescue - Run a rescue shell on a virtual machine
=head1 SYNOPSIS
virt-rescue [--options] domname
virt-rescue [--options] disk.img [disk.img ...]
=head1 WARNING
You must I<not> use C<virt-rescue> on live virtual machines. Doing so
will probably result in disk corruption in the VM. C<virt-rescue>
tries to stop you from doing this, but doesn't catch all cases.
However if you use the I<--ro> (read only) option, then you can attach
a shell to a live virtual machine, but the results might be strange or
inconsistent at times (but you won't get disk corruption).
=head1 DESCRIPTION
virt-rescue gives you a rescue shell and some simple recovery tools
which you can use on a virtual machine disk image.
After running virt-rescue, what you see under C</> is the recovery
appliance.
You must mount the virtual machine's filesystems by hand. There
is a directory C</sysroot> where you can mount filesystems. For
example:
><rescue> lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
lv_root vg_f11x64 -wi-a- 8.83G
lv_swap vg_f11x64 -wi-a- 992.00M
><rescue> mount /dev/vg_f11x64/lv_root /sysroot
><rescue> ls /sysroot
This tool is just designed for quick interactive hacking on a virtual
machine. For more structured access to a virtual machine disk image,
you should use L<guestfs(3)>. To get a structured shell, use
L<guestfish(1)>.
=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 $readonly;
=item B<--ro> | B<-r>
Open the image read-only.
The option must always be used if the disk image or virtual machine
might be running, and is generally recommended in cases where you
don't need write access to the disk.
=back
=cut
GetOptions ("help|?" => \$help,
"version" => \$version,
"connect|c=s" => \$uri,
"ro|r" => \$readonly,
) 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-rescue: no image or VM names rescue given")
if @ARGV == 0;
my @args = (\@ARGV);
push @args, address => $uri if $uri;
push @args, rw => 1 unless $readonly;
my $g = open_guest (@args);
$g->set_direct (1);
$g->set_append ("guestfs_rescue=1");
$g->launch ();
exit 0;
=head1 SEE ALSO
L<guestfs(3)>,
L<guestfish(1)>,
L<virt-cat(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://people.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.
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