File xend-migration-bridge-check.patch of Package xen.481

bnc#757525

Index: xen-4.2.0-testing/tools/python/xen/xend/server/netif.py
===================================================================
--- xen-4.2.0-testing.orig/tools/python/xen/xend/server/netif.py
+++ xen-4.2.0-testing/tools/python/xen/xend/server/netif.py
@@ -23,6 +23,7 @@
 import os
 import random
 import re
+import commands
 
 from xen.xend import XendOptions, sxp
 from xen.xend.server.DevController import DevController
@@ -101,6 +102,14 @@ class NetifController(DevController):
     def __init__(self, vm):
         DevController.__init__(self, vm)
 
+    def createDevice(self, config):
+        bridge = config.get('bridge')
+        if bridge is not None:
+            bridge_result = commands.getstatusoutput("/sbin/ifconfig %s" % bridge)
+            if bridge_result[0] != 0:
+                raise VmError('Network bridge does not exist: %s' % bridge)
+        DevController.createDevice(self, config)
+
     def getDeviceDetails(self, config):
         """@see DevController.getDeviceDetails"""