tests: rsync: Skip this test when the backend is libvirt.

It would work, except if you have a host firewall which will block
inbound connections on virbr0 to non-standard ports.

tests/rsync/test-rsync.sh

@@ -33,10 +33,33 @@ if ! rsync --help >/dev/null 2>&1; then
     exit 77
 fi
 
-if [ "$(guestfish get-backend)" = "uml" ]; then
-    echo "$0: skipping test because networking is not available in the UML backend"
-    exit 77
-fi
+# Get host IP address.  XXX Bit of a hack.
+backend="$(guestfish get-backend)"
+case "$backend" in
+    direct)
+        ip=169.254.2.2
+        listen_address=localhost
+        ;;
+    libvirt|libvirt:*)
+        # This would work, except that the host firewall is effective
+        # on virbr0, and that is likely to block the non-standard port
+        # number that we listen on.
+#        ip="$(ip -4 -o address show virbr0 |
+#                  awk '{print $4}' |
+#                  awk -F/ '{print $1}')"
+#        listen_address="$ip"
+        echo "$0: skipping test because host firewall will probably prevent this test from working"
+        exit 77
+        ;;
+    uml)
+        echo "$0: skipping test because networking is not available in the UML backend"
+        exit 77
+        ;;
+    *)
+        echo "$0: don't know how to get IP address of backend $backend"
+        exit 77
+        ;;
+esac
 
 # If rsync is not available, bail.
 if ! guestfish -a /dev/null run : available rsync; then
@@ -56,7 +79,7 @@ port="$(awk 'BEGIN{srand(); print 65000+int(500*rand())}' </dev/null)"
 
 # Write an rsync daemon config file.
 cat > rsyncd.conf <<EOF
-address = localhost
+address = $listen_address
 port = $port
 pid file = $pwd/rsyncd.pid
 [src]
@@ -80,8 +103,6 @@ function cleanup ()
 }
 trap cleanup INT TERM QUIT EXIT
 
-# XXX
-ip=169.254.2.2
 user="$(id -un)"
 
 guestfish --network -N test-rsync.img=fs -m /dev/sda1 <<EOF