[PATCH RFC 5/5] Grant table for console, xenstore pages

[Diego Ongaro <diego.ongaro@citrix.com>]

If each of the files /var/run/{console,xenstore}.did contains an
integer, this integer is interpreted as the domain id for that daemon.
The default or fallback is domid=0, of course. In this patch, xend is
modified to use this mechanism for the allocated unbound ports.

Signed-off-by: Diego Ongaro <diego.ongaro@citrix.com>
---
diff -r 581c5525e1ac tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py	Thu Jul 10 19:50:48 2008 +0100
+++ b/tools/python/xen/xend/XendDomainInfo.py	Fri Jul 11 15:30:06 2008 +0100
@@ -2427,17 +2427,26 @@
     def _createChannels(self):
         """Create the channels to the domain.
         """
-        self.store_port = self._createChannel()
-        self.console_port = self._createChannel()
+        def read_domid(service):
+            try:
+                f = open("/var/run/%s.did" % service)
+                try:
+                    return int(f.read())
+                finally:
+                    f.close()
+            except (IOError, ValueError):
+                return 0 # assume domain 0 is providing service
 
+        self.store_port = self._createChannel(read_domid("xenstore"))
+        self.console_port = self._createChannel(read_domid("console"))
 
-    def _createChannel(self):
+    def _createChannel(self, remote_dom):
         """Create an event channel to the domain.
         """
         try:
             if self.domid != None:
                 return xc.evtchn_alloc_unbound(domid = self.domid,
-                                               remote_dom = 0)
+                                               remote_dom = remote_dom)
         except:
             log.exception("Exception in alloc_unbound(%s)", str(self.domid))
             raise