1 files changed, 92 insertions, 0 deletions
diff --git a/virsh-ga b/virsh-ga
new file mode 100755
index 0000000..2b26c82
--- /dev/null
+++ b/virsh-ga
@@ -0,0 +1,92 @@
+#!/usr/bin/perl
+
+# Send command to a guest's QEMU Agent to access its file.
+# Usage: virsh-ga [--connect=URI] DOMAIN COMMAND [ARGUMENT..]
+#
+# Return value:
+#   - 0 on success,
+#   - 128 if the QEMU agent is not connected, and
+#   - 1 on error.
+
+
+# Clean up PATH
+$ENV{PATH} = join ':', qw{/usr/bin /bin};
+delete @ENV{qw/IFS CDPATH ENV BASH_ENV/};
+
+use warnings;
+use strict;
+
+use Symbol 'gensym';
+use IO::Select ();
+use IPC::Open3 'open3';
+use JSON ();
+use MIME::Base64 'decode_base64';
+use Getopt::Long qw/:config posix_default no_ignore_case gnu_getopt auto_version auto_help/;
+
+my %OPTIONS;
+GetOptions(\%OPTIONS, qw/connect|c=s/) or die;
+my $DOMAIN  = shift // die;
+my $COMMAND = shift // die;
+
+my @VIRSH = ('virsh');
+push @VIRSH, '--connect='.$OPTIONS{connect} if defined $OPTIONS{connect};
+
+sub ga_send(@) {
+    my @command = (@VIRSH, 'qemu-agent-command', '--block', $DOMAIN, JSON->new->encode({ @_ }));
+    my $pid = open3(my $in, my $out, my $err = gensym(), @command);
+    my $sel = IO::Select::->new($out, $err);
+    my %str;
+    while (my @fhs = $sel->can_read) {
+        foreach my $fh (@fhs) {
+            my $x = $fh->getline;
+            if (defined $x) {
+                $str{$fh} .= $x;
+            } else {
+                $sel->remove($fh);
+            }
+        }
+    }
+    waitpid $pid, 0;
+    close $_ foreach ($in, $out, $err);
+    if ($? == 0) {
+        my $h = JSON->new->utf8->allow_nonref->decode($str{$out});
+        return $h->{return};
+    }
+    elsif ($str{$err} eq "error: Guest agent is not responding: QEMU guest agent is not connected\n") {
+        exit 128;
+    } else {
+        die $str{$err};
+    }
+}
+
+# the JSON domain definition can be found in QEMU's qga/qapi-schema.json
+if ($COMMAND eq 'info') {
+    ga_send(execute => 'guest-info');
+}
+elsif ($COMMAND eq 'ping') {
+    ga_send(execute => 'guest-ping');
+}
+elsif ($COMMAND eq 'cat') {
+    die unless @ARGV;
+    foreach my $path (@ARGV) {
+        my $fh = ga_send(execute => 'guest-file-open', arguments => {path => $path, mode => 'r'});
+
+        my ($b64, $eof);
+        do {
+            # keep reading until we reach EOF
+            my $r = ga_send(execute => 'guest-file-read', arguments => {handle => $fh});
+            $b64 .= $r->{'buf-b64'};
+            $eof = $r->{eof};
+        } until ($eof);
+        print decode_base64($b64);
+
+        ga_send(execute => 'guest-file-close', arguments => {handle => $fh});
+    }
+}
+elsif ($COMMAND eq 'touch') {
+    die unless @ARGV;
+    foreach my $path (@ARGV) {
+        my $fh = ga_send(execute => 'guest-file-open', arguments => {path => $path, mode => 'a'});
+        ga_send(execute => 'guest-file-close', arguments => {handle => $fh});
+    }
+}