Domain core-dumping fixes

The code was attempting to use the domain's current number of pages
(info.nr_pages) as a maximum index.  We then walk the memory map and
can easily over-write past the end of the nr_pages-sized array, if the
domain has more pages mapped in than earlier (live dump).  Restrict
ourselves to the current number of pages.

Also fix the dump core method in xend to actually implement the crash
and live options.  In particular this means that xend clients other
than xm now get non-live dumps by default.

Signed-off-by: John Levon <john.levon@sun.com>

tools/python/xen/xend/XendDomain.py

@@ -1237,13 +1237,23 @@ class XendDomain:
                              POWER_STATE_NAMES[DOM_STATE_PAUSED],
                              POWER_STATE_NAMES[dominfo._stateGet()])
 
+        dopause = (not live and dominfo._stateGet() == DOM_STATE_RUNNING)
+        if dopause:
+            dominfo.pause()
+
         try:
-            log.info("Domain core dump requested for domain %s (%d) "
-                     "live=%d crash=%d.",
-                     dominfo.getName(), dominfo.getDomid(), live, crash)
-            return dominfo.dumpCore(filename)
-        except Exception, ex:
-            raise XendError(str(ex))
+            try:
+                log.info("Domain core dump requested for domain %s (%d) "
+                         "live=%d crash=%d.",
+                         dominfo.getName(), dominfo.getDomid(), live, crash)
+                dominfo.dumpCore(filename)
+                if crash:
+                    self.domain_destroy(domid)
+            except Exception, ex:
+                raise XendError(str(ex))
+        finally:
+            if dopause and not crash:
+                dominfo.unpause()
 
     def domain_destroy(self, domid):
         """Terminate domain immediately.

tools/python/xen/xend/XendDomainInfo.py

@@ -2027,26 +2027,31 @@ class XendDomainInfo:
         @raise: XendError if core dumping failed.
         """
         
-        try:
-            if not corefile:
-                this_time = time.strftime("%Y-%m%d-%H%M.%S", time.localtime())
-                corefile = "/var/xen/dump/%s-%s.%s.core" % (this_time,
-                                  self.info['name_label'], self.domid)
+        if not corefile:
+            this_time = time.strftime("%Y-%m%d-%H%M.%S", time.localtime())
+            corefile = "/var/xen/dump/%s-%s.%s.core" % (this_time,
+                              self.info['name_label'], self.domid)
                 
-            if os.path.isdir(corefile):
-                raise XendError("Cannot dump core in a directory: %s" %
-                                corefile)
-            
-            self._writeVm(DUMPCORE_IN_PROGRESS, 'True')
-            xc.domain_dumpcore(self.domid, corefile)
+        if os.path.isdir(corefile):
+            raise XendError("Cannot dump core in a directory: %s" %
+                            corefile)
+
+        try:
+            try:
+                self._writeVm(DUMPCORE_IN_PROGRESS, 'True')
+                xc.domain_dumpcore(self.domid, corefile)
+            except RuntimeError, ex:
+                corefile_incomp = corefile+'-incomplete'
+                try:
+                    os.rename(corefile, corefile_incomp)
+                except:
+                    pass
+
+                log.error("core dump failed: id = %s name = %s: %s",
+                          self.domid, self.info['name_label'], str(ex))
+                raise XendError("Failed to dump core: %s" %  str(ex))
+        finally:
             self._removeVm(DUMPCORE_IN_PROGRESS)
-        except RuntimeError, ex:
-            corefile_incomp = corefile+'-incomplete'
-            os.rename(corefile, corefile_incomp)
-            self._removeVm(DUMPCORE_IN_PROGRESS)
-            log.exception("XendDomainInfo.dumpCore failed: id = %s name = %s",
-                          self.domid, self.info['name_label'])
-            raise XendError("Failed to dump core: %s" %  str(ex))
 
     #
     # Device creation/deletion functions

tools/python/xen/xm/main.py

@@ -1351,22 +1351,10 @@ def xm_dump_core(args):
     else:
         filename = None
 
-    if not live:
-        ds = server.xend.domain.pause(dom, True)
-
-    try:
-        print "Dumping core of domain: %s ..." % str(dom)
-        server.xend.domain.dump(dom, filename, live, crash)
-
-        if crash:
-            print "Destroying domain: %s ..." % str(dom)
-            server.xend.domain.destroy(dom)
-        elif reset:
-            print "Resetting domain: %s ..." % str(dom)
-            server.xend.domain.reset(dom)
-    finally:
-        if not live and not crash and not reset and ds == DOM_STATE_RUNNING:
-            server.xend.domain.unpause(dom)
+    print "Dumping core of domain: %s ..." % str(dom)
+    server.xend.domain.dump(dom, filename, live, crash)
+    if reset:
+        server.xend.domain.reset(dom)
 
 def xm_rename(args):
     arg_check(args, "rename", 2)