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Add 'virt-rescue' command.

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This command runs a "rescue appliance" against a virtual machine
or disk image.  This is useful for making ad-hoc interactive
changes to virtual machines.

  $ virt-rescue --ro /dev/vg_trick/F11x64

  Welcome to virt-rescue, the libguestfs rescue shell.

  Note: The contents of / are the rescue appliance.
  You have to mount the guest's partitions under /sysroot
  before you will be able to examine them.

  bash: cannot set terminal process group (-1): Inappropriate ioctl for device
  bash: no job control in this shell
  ><rescue> mount /dev/vg_f11x64/lv_root /sysroot
  EXT4-fs (dm-0): barriers enabled
  kjournald2 starting: pid 269, dev dm-0:8, commit interval 5 seconds
  EXT4-fs (dm-0): internal journal on dm-0:8
  EXT4-fs (dm-0): delayed allocation enabled
  EXT4-fs: file extents enabled
  EXT4-fs: mballoc enabled
  EXT4-fs (dm-0): mounted filesystem with ordered data mode
  ><rescue> ls /sysroot/
  bin   dev  home  lib64       media  opt   root  selinux  sys  usr
  boot  etc  lib   lost+found  mnt    proc  sbin  srv      tmp  var
  ><rescue> exit
This commit is contained in:
Richard Jones
2009-09-22 19:50:21 +01:00
parent 3bc5555135
commit 1b21ed4f5d
10 changed files with 309 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
.gitignore vendored
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@@ -74,6 +74,7 @@ html/recipes.html
html/virt-cat.1.html
html/virt-df.1.html
html/virt-inspector.1.html
html/virt-rescue.1.html
images/100kallnewlines
images/100kallspaces
images/100kallzeroes
@@ -170,6 +171,7 @@ python/guestfs.py
python/guestfs-py.c
python/guestfs.pyc
regressions/test1.img
rescue/virt-rescue.1
ruby/bindtests.rb
ruby/ext/guestfs/extconf.h
ruby/ext/guestfs/_guestfs.c

3
HACKING
View File

@@ -122,6 +122,9 @@ python/
regressions/
Regression tests.
rescue/
The virt-rescue tool.
ruby/
Ruby bindings.

3
Makefile.am
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@@ -47,6 +47,9 @@ endif
if HAVE_CAT
SUBDIRS += cat
endif
if HAVE_RESCUE
SUBDIRS += rescue
endif
EXTRA_DIST = \
guestfs.pod guestfs-actions.pod guestfs-structs.pod \

16
TODO
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@@ -264,3 +264,19 @@ quickly, eg:
load ext2
Maybe it's better to create these on the fly?
virt-rescue pty
---------------
See:
http://search.cpan.org/~rgiersig/IO-Tty-1.08/Pty.pm
http://www.perlmonks.org/index.pl?node_id=582185
Note that pty requires cooperation inside the C code too (there are
two sides to a pty, and one has to be handled after the fork).
virt-rescue TERM
----------------
Pass TERM from the library, through the kernel command line, to the
init script.

8
appliance/init
View File

@@ -65,7 +65,15 @@ if ! grep -sq guestfs_rescue=1 /proc/cmdline; then
exec guestfsd -f
fi
# Use appliance in rescue mode, also used by the virt-rescue command.
TERM=linux ;# XXX library should pass this from library's environment
PS1='><rescue> '
export TERM PS1
echo
echo "Welcome to virt-rescue, the libguestfs rescue shell."
echo
echo "Note: The contents of / are the rescue appliance."
echo "You have to mount the guest's partitions under /sysroot"
echo "before you can examine them."
echo
exec bash -i

7
configure.ac
View File

@@ -653,7 +653,7 @@ for pm in Pod::Usage Getopt::Long Sys::Virt Data::Dumper XML::Writer Locale::Tex
fi
done
if test "x$missing_perl_modules" = "xyes"; then
AC_MSG_WARN([some Perl modules required to compile virt-cat, virt-df and virt-inspector are missing])
AC_MSG_WARN([some Perl modules required to compile virt-cat, virt-df, virt-inspector and virt-rescue are missing])
fi
AM_CONDITIONAL([HAVE_CAT],
@@ -662,6 +662,8 @@ AM_CONDITIONAL([HAVE_DF],
[test "x$PERL" != "xno" -a "x$missing_perl_modules" != "xyes"])
AM_CONDITIONAL([HAVE_INSPECTOR],
[test "x$PERL" != "xno" -a "x$missing_perl_modules" != "xyes"])
AM_CONDITIONAL([HAVE_RESCUE],
[test "x$PERL" != "xno" -a "x$missing_perl_modules" != "xyes"])
dnl Library versioning.
MAX_PROC_NR=`cat $srcdir/src/MAX_PROC_NR`
@@ -700,6 +702,7 @@ AC_CONFIG_FILES([Makefile
cat/Makefile
df/Makefile
inspector/Makefile
rescue/Makefile
libguestfs.pc
gnulib/lib/Makefile
gnulib/tests/Makefile
@@ -733,6 +736,8 @@ echo -n "virt-df ............................. "
if test "x$HAVE_DF" = "x"; then echo "yes"; else echo "no"; fi
echo -n "virt-inspector ...................... "
if test "x$HAVE_INSPECTOR" = "x"; then echo "yes"; else echo "no"; fi
echo -n "virt-rescue ......................... "
if test "x$HAVE_RESCUE" = "x"; then echo "yes"; else echo "no"; fi
echo "supermin appliance .................. $enable_supermin"
echo
echo "If any optional component is configured 'no' when you expected 'yes'"

1
po/POTFILES.in
View File

@@ -80,6 +80,7 @@ perl/lib/Sys/Guestfs.pm
perl/lib/Sys/Guestfs/Lib.pm
python/guestfs-py.c
regressions/test-noexec-stack.pl
rescue/virt-rescue.pl
ruby/ext/guestfs/_guestfs.c
src/guestfs-actions.c
src/guestfs-bindtests.c

48
rescue/Makefile.am Normal file
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@@ -0,0 +1,48 @@
# libguestfs 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.
EXTRA_DIST = \
run-rescue-locally \
virt-rescue.pl
if HAVE_RESCUE
man_MANS = virt-rescue.1
noinst_DATA = @top_builddir@/html/virt-rescue.1.html
virt-rescue.1: virt-rescue.pl
$(POD2MAN) \
--section 1 \
-c "Virtualization Support" \
--release "$(PACKAGE_NAME)-$(PACKAGE_VERSION)" \
$< > $@
@top_builddir@/html/virt-rescue.1.html: virt-rescue.pl
mkdir -p @top_builddir@/html
cd @top_builddir@ && pod2html \
--css 'pod.css' \
--title 'virt-rescue, run a rescue shell on a virtual machine' \
--htmldir html \
--outfile html/virt-rescue.1.html \
rescue/$<
install-data-hook:
mkdir -p $(DESTDIR)$(bindir)
install -m 0755 virt-rescue.pl $(DESTDIR)$(bindir)/virt-rescue
endif

53
rescue/run-rescue-locally Executable file
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@@ -0,0 +1,53 @@
#!/usr/bin/perl
# 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.
# This script sets up the environment so you can run virt-rescue in
# place without needing to do 'make install' first. You can also run
# virt-rescue by creating a symlink to this script and putting it in
# your path.
#
# Use it like this:
# ./run-rescue-locally [usual virt-rescue args ...]
use strict;
use warnings;
use File::Basename qw(dirname);
use File::Spec;
use Cwd qw(abs_path);
my $path = $0;
# Follow symlinks until we get to the real file
while(-l $path) {
my $link = readlink($path);
if(File::Spec->file_name_is_absolute($link)) {
$path = $link;
} else {
$path = File::Spec->catfile(dirname($path), $link);
}
}
# Get the absolute path of the parent directory
$path = abs_path(dirname($path).'/..');
$ENV{LD_LIBRARY_PATH} = $path.'/src/.libs';
$ENV{LIBGUESTFS_PATH} = $path.'/appliance';
$ENV{PERL5LIB} = $path.'/perl/blib/lib:'.$path.'/perl/blib/arch';
exec('perl', $path.'/rescue/virt-rescue.pl', @ARGV);

169
rescue/virt-rescue.pl Executable file
View File

@@ -0,0 +1,169 @@
#!/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 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,
eg:
# 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
# mount /dev/vg_f11x64/lv_root /sysroot
# ls /sysroot
B<Note> that the virtual machine must not be powered on when you use
this tool. Doing so will probably result in disk corruption in the
VM. However if you use the I<--ro> (read only) option, then you can
attach a shell to a running machine, but the results might be strange
or inconsistent.
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.
=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://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.