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[libvirt] PATCH: Fix multiple bugs in RPC handling



A number of bugs conspired together to cause some nasty problems when
a QEMU vm failed to start

 - vm->monitor was not initialized to -1, so when a VM failed to start
   the vm->monitor was just '0', and thus we closed FD 0 (libvirtd's stdin)

 - The next client to connect got FD 0 as its socket 

 - The first bug struck again, causing the client to be closed even
   though libvirt thought it was still open
 
 - libvirtd now polle on FD=0, which gave back POLLNVAL because it was
   closed

 - event.c was not looking for POLLNVAL so it span 100% cpu when this
   happened, instead of invoking the callback with an error code

 - virsh was not cleaning up the priv->watiDispatch call upon I/O errors,
   so virsh then hung when doing virConenctClose


This patch does 3 things

 - Treats POLLNVAL as VIR_EVENT_HANDLE_ERROR, so the callback gets
   to see the error & de-registers the client from the event loop
 - Add the missing initialization of vm->monitor
 - Fix remote_internal.c handling of I/O errors

Daniel

Index: qemud/event.c
===================================================================
RCS file: /data/cvs/libvirt/qemud/event.c,v
retrieving revision 1.17
diff -u -p -u -p -r1.17 event.c
--- qemud/event.c	22 Dec 2008 12:55:47 -0000	1.17
+++ qemud/event.c	5 Feb 2009 17:12:51 -0000
@@ -653,6 +653,8 @@ virPollEventToEventHandleType(int events
         ret |= VIR_EVENT_HANDLE_WRITABLE;
     if(events & POLLERR)
         ret |= VIR_EVENT_HANDLE_ERROR;
+    if(events & POLLNVAL) /* Treat NVAL as error, since libvirt doesn't distinguish */
+        ret |= VIR_EVENT_HANDLE_ERROR;
     if(events & POLLHUP)
         ret |= VIR_EVENT_HANDLE_HANGUP;
     return ret;
Index: src/domain_conf.c
===================================================================
RCS file: /data/cvs/libvirt/src/domain_conf.c,v
retrieving revision 1.64
diff -u -p -u -p -r1.64 domain_conf.c
--- src/domain_conf.c	30 Jan 2009 21:52:22 -0000	1.64
+++ src/domain_conf.c	5 Feb 2009 17:12:51 -0000
@@ -504,6 +504,7 @@ virDomainObjPtr virDomainAssignDef(virCo
     domain->state = VIR_DOMAIN_SHUTOFF;
     domain->def = def;
     domain->monitor_watch = -1;
+    domain->monitor = -1;
 
     if (VIR_REALLOC_N(doms->objs, doms->count + 1) < 0) {
         virReportOOMError(conn);
Index: src/remote_internal.c
===================================================================
RCS file: /data/cvs/libvirt/src/remote_internal.c,v
retrieving revision 1.136
diff -u -p -u -p -r1.136 remote_internal.c
--- src/remote_internal.c	3 Feb 2009 13:08:07 -0000	1.136
+++ src/remote_internal.c	5 Feb 2009 17:12:52 -0000
@@ -6192,17 +6192,17 @@ processCalls(virConnectPtr conn,
                 continue;
             virReportSystemError(in_open ? NULL : conn, errno,
                                  "%s", _("poll on socket failed"));
-            return -1;
+            goto error;
         }
 
         if (fds[0].revents & POLLOUT) {
             if (processCallSend(conn, priv, in_open) < 0)
-                return -1;
+                goto error;
         }
 
         if (fds[0].revents & POLLIN) {
             if (processCallRecv(conn, priv, in_open) < 0)
-                return -1;
+                goto error;
         }
 
         /* Iterate through waiting threads and if
@@ -6253,9 +6253,21 @@ processCalls(virConnectPtr conn,
         if (fds[0].revents & (POLLHUP | POLLERR)) {
             errorf(in_open ? NULL : conn, VIR_ERR_INTERNAL_ERROR,
                    "%s", _("received hangup / error event on socket"));
-            return -1;
+            goto error;
         }
     }
+
+
+error:
+    priv->waitDispatch = thiscall->next;
+    DEBUG("Giving up the buck due to I/O error %d %p %p", thiscall->proc_nr, thiscall, priv->waitDispatch);
+    /* See if someone else is still waiting
+     * and if so, then pass the buck ! */
+    if (priv->waitDispatch) {
+        DEBUG("Passing the buck to %d %p", priv->waitDispatch->proc_nr, priv->waitDispatch);
+        virCondSignal(&priv->waitDispatch->cond);
+    }
+    return -1;
 }
 
 /*


-- 
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|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
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