xend: do not run a hotplug script from qemu on Linux

The current vif-hotplug-common.sh for renaming the tap device is failing
because it is racing with this script and therefore the device is unexpectedly
up when we come to rename it.

Fix this in the same way as libxl does, by disabling the script (only on
Linux).

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/python/xen/xend/image.py

@@ -919,8 +919,13 @@ class HVMImageHandler(ImageHandler):
                        (nics, mac, model))
             vifname = "vif%d.%d-emu" % (self.vm.getDomid(), nics-1)
             ret.append("-net")
-            ret.append("tap,vlan=%d,ifname=%s,bridge=%s" %
-                       (nics, vifname, bridge))
+            if osdep.tapif_script is not None:
+                script=",script=%s,downscript=%s" % \
+                        (osdep.tapif_script, osdep.tapif_script)
+            else:
+                script=""
+            ret.append("tap,vlan=%d,ifname=%s,bridge=%s%s" %
+                       (nics, vifname, bridge, script))
 
         if nics == 0:
             ret.append("-net")

tools/python/xen/xend/osdep.py

@@ -30,6 +30,10 @@ _vif_script = {
     "SunOS": "vif-vnic"
 }
 
+_tapif_script = {
+    "Linux": "no",
+}
+
 PROC_XEN_BALLOON = '/proc/xen/balloon'
 SYSFS_XEN_MEMORY = '/sys/devices/system/xen_memory/xen_memory0'
 
@@ -257,6 +261,7 @@ def _get(var, default=None):
 
 xend_autorestart = _get(_xend_autorestart)
 vif_script = _get(_vif_script, "vif-bridge")
+tapif_script = _get(_tapif_script)
 lookup_balloon_stat = _get(_balloon_stat, _linux_balloon_stat)
 get_cpuinfo = _get(_get_cpuinfo, _linux_get_cpuinfo)
 prefork = _get(_get_prefork, _default_prefork)