This patch adds a check in xend that prevents a user from trying to

destroy Dom0.  Currently, xm does not return an error for this case.
Xend tries to destroy dom0 and leaves the system in an unstable
state.  Subsequent attempts to create a domain result in the following
error message:

  Error: Error creating domain: (106, 'Transport endpoint is already \
  connected')

This will fix bugzilla bug #243

Signed-off-by: Dan Smith <danms@us.ibm.com>

tools/python/xen/xend/XendDomain.py

@@ -42,6 +42,7 @@ from xen.xend.xenstore.xsutil import GetDomainPath
 __all__ = [ "XendDomain" ]
 
 SHUTDOWN_TIMEOUT = 30
+PRIV_DOMAIN      =  0
 
 def is_dead(dom):
     return dom['crashed'] or dom['shutdown'] or (
@@ -163,7 +164,7 @@ class XendDomain:
         self.domain_restarts()
 
     def dom0_setup(self):
-        dom0 = self.domain_lookup(0)
+        dom0 = self.domain_lookup(PRIV_DOMAIN)
         if not dom0:
             dom0 = self.dom0_unknown()
         dom0.dom0_init_store()    
@@ -331,7 +332,7 @@ class XendDomain:
         return self.domains.get(id)
 
     def dom0_unknown(self):
-        dom0 = 0
+        dom0 = PRIV_DOMAIN
         uuid = None
         info = self.xen_domain(dom0)
         dompath = GetDomainPath(dom0)
@@ -499,6 +500,10 @@ class XendDomain:
 
         @param domid: domain id
         """
+
+        if domid == PRIV_DOMAIN:
+            raise XendError("Cannot destroy priviliged domain %i" % domid)
+        
         self.domain_restart_schedule(domid, reason, force=True)
         dominfo = self.domain_lookup(domid)
         if dominfo: