daemon: Write "already running" message to log also.

Otherwise it's hard to diagnose later if the daemon failed to start because
it thinks that it is already running.

lib/daemon.c

@@ -171,6 +171,8 @@ die_if_already_running(void)
     pid_t pid = already_running();
     if (pid) {
         if (!overwrite_pidfile) {
+            VLOG_ERR("%s: %s already running as pid %ld, aborting",
+                      get_pidfile(), program_name, (long int) pid);
             ovs_fatal(0, "%s: already running as pid %ld",
                       get_pidfile(), (long int) pid);
         } else {

python/ovs/daemon.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2010 Nicira Networks
+# Copyright (c) 2010, 2011 Nicira Networks
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -141,7 +141,9 @@ def die_if_already_running():
     ignore_existing_pidfile() has been called, terminate the program."""
     if _already_running():
         if not _overwrite_pidfile:
-            sys.stderr.write("%s: already running\n" % get_pidfile())
+            msg = "%s: already running" % _pidfile
+            logging.error("%s, aborting" % msg)
+            sys.stderr.write("%s\n" % msg)
             sys.exit(1)
         else:
             logging.warn("%s: %s already running"