#!/usr/bin/perl -w
# virt-edit
-# Copyright (C) 2009 Red Hat Inc.
+# Copyright (C) 2009-2010 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
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 Sys::Guestfs::Lib qw(open_guest);
use Pod::Usage;
use Getopt::Long;
use File::Temp qw/tempfile/;
+use File::Basename;
use Locale::TextDomain 'libguestfs';
=encoding utf8
virt-edit [--options] disk.img [disk.img ...] file
+ virt-edit [domname|disk.img] file -e 'expr'
+
+=head1 WARNING
+
+You must I<not> use C<virt-edit> on live virtual machines. If you do
+this, you risk disk corruption in the VM. C<virt-edit> tries to stop
+you from doing this, but doesn't catch all cases.
+
=head1 DESCRIPTION
C<virt-edit> is a command line tool to edit C<file> where C<file>
exists in the named virtual machine (or disk image).
-B<Note> you must I<not> use virt-edit on live virtual machines. If
-you do this, you risk disk corruption in the VM.
-
If you want to just view a file, use L<virt-cat(1)>. For more complex
cases you should look at the L<guestfish(1)> tool.
=head1 EXAMPLES
+Edit the named files interactively:
+
virt-edit mydomain /boot/grub/grub.conf
virt-edit mydomain /etc/passwd
+You can also edit files non-interactively (see
+L</NON-INTERACTIVE EDITING> below).
+To change the init default level to 5:
+
+ virt-edit mydomain /etc/inittab -e 's/^id:.*/id:5:initdefault:/'
+
=head1 OPTIONS
=over 4
=cut
+my $backup;
+
+=item B<--backup extension> | B<-b extension>
+
+Create a backup of the original file I<in the guest disk image>.
+The backup has the original filename with C<extension> added.
+
+Usually the first character of C<extension> would be a dot C<.>
+so you would write:
+
+ virt-edit -b .orig [etc]
+
+By default, no backup file is made.
+
+=cut
+
my $uri;
=item B<--connect URI> | B<-c URI>
If you specify guest block devices directly, then libvirt is not used
at all.
+=cut
+
+my $format;
+
+=item B<--format> raw
+
+Specify the format of disk images given on the command line. If this
+is omitted then the format is autodetected from the content of the
+disk image.
+
+If disk images are requested from libvirt, then this program asks
+libvirt for this information. In this case, the value of the format
+parameter is ignored.
+
+If working with untrusted raw-format guest disk images, you should
+ensure the format is always specified.
+
+=cut
+
+my $expr;
+
+=item B<--expr EXPR> | B<-e EXPR>
+
+Instead of launching the external editor, non-interactively
+apply the Perl expression C<EXPR> to each line in the file.
+See L</NON-INTERACTIVE EDITING> below.
+
+Be careful to properly quote the expression to prevent it from
+being altered by the shell.
+
=back
=cut
GetOptions ("help|?" => \$help,
"version" => \$version,
"connect|c=s" => \$uri,
+ "format=s" => \$format,
+ "expr|e=s" => \$expr,
+ "backup|b=s" => \$backup,
) or pod2usage (2);
pod2usage (1) if $help;
if ($version) {
my $g;
if ($uri) {
- $g = open_guest (\@ARGV, address => $uri, rw => 1);
+ $g = open_guest (\@ARGV, address => $uri, rw => 1, format => $format);
} else {
- $g = open_guest (\@ARGV, rw => 1);
+ $g = open_guest (\@ARGV, rw => 1, format => $format);
}
$g->launch ();
-# List of possible filesystems.
-my @partitions = get_partitions ($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 = $g->inspect_os ();
+if (@roots == 0) {
+ die __x("{prog}: No operating system could be detected inside this disk image.\n\nThis may be because the file is not a disk image, or is not a virtual machine\nimage, or because the OS type is not understood by libguestfs.\n\nIf you feel this is an error, please file a bug report including as much\ninformation about the disk image as possible.\n",
+ prog => basename ($0));
+}
+if (@roots > 1) {
+ die __x("{prog}: multiboot operating systems are not supported.\n",
+ prog => basename ($0))
+}
+my %fses = $g->inspect_get_mountpoints ($roots[0]);
+my @fses = sort { length $a <=> length $b } keys %fses;
+foreach (@fses) {
+ $g->mount_options ("", $fses{$_}, $_);
+}
-my @roots = keys %$oses;
-die __"no root device found in this operating system image" if @roots == 0;
-die __"multiboot operating systems are not supported by virt-edit" if @roots > 1;
-my $root_dev = $roots[0];
+my ($fh, $tempname) = tempfile (UNLINK => 1);
+my $fddev = "/dev/fd/" . fileno ($fh);
-my $os = $oses->{$root_dev};
-mount_operating_system ($g, $os, 0);
+# Allow this to fail in case eg. the file does not exist.
+$g->download ($filename, $fddev);
-my ($fh, $tempname) = tempfile ();
+close $fh or die "close: $!";
-# Allow this to fail in case eg. the file does not exist.
-$g->download($filename, $tempname);
+my $do_upload = $tempname;
-my $oldctime = (stat ($tempname))[10];
+if (!defined $expr) {
+ # Interactively edit the file.
+ my $oldctime = (stat ($tempname))[10];
-my $editor = $ENV{EDITOR};
-$editor ||= "vi";
-system ("$editor $tempname") == 0
- or die "edit failed: $editor: $?";
+ my $editor = $ENV{EDITOR};
+ $editor ||= "vi";
+ system ("$editor $tempname") == 0
+ or die "edit failed: $editor: $?";
-my $newctime = (stat ($tempname))[10];
+ my $newctime = (stat ($tempname))[10];
-if ($oldctime != $newctime) {
- $g->upload ($tempname, $filename)
+ if ($oldctime == $newctime) {
+ $do_upload = undef;
+ print __"File not changed.\n";
+ }
} else {
- print __"File not changed.\n";
+ my ($fh, $tempout) = tempfile (UNLINK => 1);
+
+ # Apply a Perl expression to the lines of the file.
+ open IFILE, $tempname or die "$tempname: $!";
+ my $lineno = 0;
+ while (<IFILE>) {
+ $lineno++;
+ eval $expr;
+ die if $@;
+ print $fh $_ or die "print: $!";
+ }
+ close $fh or die "close: $!";
+
+ $do_upload = $tempout;
}
-$g->sync ();
-$g->umount_all ();
+if (defined $do_upload) {
+ # Upload to a new file, so if it fails we don't end up with
+ # a partially written file. Give the new file a completely
+ # random name so we have only a tiny chance of overwriting
+ # some existing file.
+ my $dirname = $filename;
+ $dirname =~ s{/[^/]+$}{/};
+
+ my @chars = ('a'..'z', 'A'..'Z', '0'..'9');
+ my $newname = $dirname;
+ foreach (0..7) {
+ $newname .= $chars[rand @chars];
+ }
+
+ $g->upload ($do_upload, $newname);
+
+ # Backup or overwrite?
+ $g->mv ($filename, "$filename$backup") if defined $backup;
+ $g->mv ($newname, $filename);
+
+ $g->umount_all ();
+ $g->sync ();
+}
undef $g;
exit 0;
+=head1 NON-INTERACTIVE EDITING
+
+C<virt-edit> normally calls out to C<$EDITOR> (or vi) so
+the system administrator can interactively edit the file.
+
+There are two ways also to use C<virt-edit> from scripts in order to
+make automated edits to files. (Note that although you I<can> use
+C<virt-edit> like this, it's less error-prone to write scripts
+directly using the libguestfs API and Augeas for configuration file
+editing.)
+
+The first method is to temporarily set C<$EDITOR> to any script or
+program you want to run. The script is invoked as C<$EDITOR tmpfile>
+and it should update C<tmpfile> in place however it likes.
+
+The second method is to use the C<-e> parameter of C<virt-edit> to run
+a short Perl snippet in the style of L<sed(1)>. For example to
+replace all instances of C<foo> with C<bar> in a file:
+
+ virt-edit domname filename -e 's/foo/bar/'
+
+The full power of Perl regular expressions can be used (see
+L<perlre(1)>). For example to delete root's password you could do:
+
+ virt-edit domname /etc/passwd -e 's/^root:.*?:/root::/'
+
+What really happens is that the snippet is evaluated as a Perl
+expression for each line of the file. The line, including the final
+C<\n>, is passed in C<$_> and the expression should update C<$_> or
+leave it unchanged.
+
+To delete a line, set C<$_> to the empty string. For example, to
+delete the C<apache> user account from the password file you can do:
+
+ virt-edit mydomain /etc/passwd -e '$_ = "" if /^apache:/'
+
+To insert a line, prepend or append it to C<$_>. However appending
+lines to the end of the file is rather difficult this way since there
+is no concept of "last line of the file" - your expression just
+doesn't get called again. You might want to use the first method
+(setting C<$EDITOR>) if you want to do this.
+
+The variable C<$lineno> contains the current line number.
+As is traditional, the first line in the file is number C<1>.
+
+The return value from the expression is ignored, but the expression
+may call C<die> in order to abort the whole program, leaving the
+original file untouched.
+
+Remember when matching the end of a line that C<$_> may contain the
+final C<\n>, or (for DOS files) C<\r\n>, or if the file does not end
+with a newline then neither of these. Thus to match or substitute
+some text at the end of a line, use this regular expression:
+
+ /some text(\r?\n)?$/
+
+Alternately, use the perl C<chomp> function, being careful not to
+chomp C<$_> itself (since that would remove all newlines from the
+file):
+
+ my $m = $_; chomp $m; $m =~ /some text$/
+
=head1 ENVIRONMENT VARIABLES
=over 4
=back
+=head1 SHELL QUOTING
+
+Libvirt guest names can contain arbitrary characters, some of which
+have meaning to the shell such as C<#> and space. You may need to
+quote or escape these characters on the command line. See the shell
+manual page L<sh(1)> for details.
+
=head1 SEE ALSO
L<guestfs(3)>,
L<Sys::Guestfs(3)>,
L<Sys::Guestfs::Lib(3)>,
L<Sys::Virt(3)>,
-L<http://libguestfs.org/>.
+L<http://libguestfs.org/>,
+L<perl(1)>,
+L<perlre(1)>.
=head1 AUTHOR
-Richard W.M. Jones L<http://et.redhat.com/~rjones/>
+Richard W.M. Jones L<http://people.redhat.com/~rjones/>
=head1 COPYRIGHT
-Copyright (C) 2009 Red Hat Inc.
+Copyright (C) 2009-2010 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
git.annexia.org / libguestfs.git / blobdiff