1 files changed, 20 insertions, 2 deletions
diff --git a/tools/virt-cat b/tools/virt-cat
index 67506c0b..66806a1a 100755
--- a/tools/virt-cat
+++ b/tools/virt-cat
@@ -109,6 +109,23 @@ connect to the default libvirt hypervisor.
 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.
+
 =back
 
 =cut
@@ -116,6 +133,7 @@ at all.
 GetOptions ("help|?" => \$help,
             "version" => \$version,
             "connect|c=s" => \$uri,
+            "format=s" => \$format,
     ) or pod2usage (2);
 pod2usage (1) if $help;
 if ($version) {
@@ -132,9 +150,9 @@ my $filename = pop @ARGV;
 
 my $g;
 if ($uri) {
-    $g = open_guest (\@ARGV, address => $uri);
+    $g = open_guest (\@ARGV, address => $uri, format => $format);
 } else {
-    $g = open_guest (\@ARGV);
+    $g = open_guest (\@ARGV, format => $format);
 }
 
 $g->launch ();