Bug #12673: Instance Manager: allows to stop the instance many times

  The instance manager was not actually checking whether an instance
  was actually running before trying to stop it. Now it checks first.

mysql-test/r/im_life_cycle.result

@@ -74,3 +74,6 @@ START INSTANCE mysqld1,mysqld2,mysqld3;
 ERROR 42000: You have an error in your command syntax. Check the manual that corresponds to your MySQL Instance Manager version for the right syntax to use
 STOP INSTANCE mysqld1,mysqld2,mysqld3;
 ERROR 42000: You have an error in your command syntax. Check the manual that corresponds to your MySQL Instance Manager version for the right syntax to use
+STOP INSTANCE mysqld2;
+ERROR HY000: Cannot stop instance. Perhaps the instance is not started, or was started manually, so IM cannot find the pidfile.
+End of 5.0 tests

mysql-test/t/im_life_cycle.imtest

@@ -218,3 +218,11 @@ START INSTANCE mysqld1,mysqld2,mysqld3;
 
 --error ER_SYNTAX_ERROR
 STOP INSTANCE mysqld1,mysqld2,mysqld3;
+
+#
+# Bug #12673: Instance Manager: allows to stop the instance many times
+#
+--error 3001
+STOP INSTANCE mysqld2;
+
+--echo End of 5.0 tests

server-tools/instance-manager/instance.cc

@@ -469,37 +469,38 @@ int Instance::stop()
   struct timespec timeout;
   uint waitchild= (uint)  DEFAULT_SHUTDOWN_DELAY;
 
-  if (options.shutdown_delay_val)
-    waitchild= options.shutdown_delay_val;
+  if (is_running())
+  {
+    if (options.shutdown_delay_val)
+      waitchild= options.shutdown_delay_val;
 
-  kill_instance(SIGTERM);
-  /* sleep on condition to wait for SIGCHLD */
+    kill_instance(SIGTERM);
+    /* sleep on condition to wait for SIGCHLD */
 
-  timeout.tv_sec= time(NULL) + waitchild;
-  timeout.tv_nsec= 0;
-  if (pthread_mutex_lock(&LOCK_instance))
-    goto err;
+    timeout.tv_sec= time(NULL) + waitchild;
+    timeout.tv_nsec= 0;
+    if (pthread_mutex_lock(&LOCK_instance))
+      return ER_STOP_INSTANCE;
 
-  while (options.get_pid() != 0)              /* while server isn't stopped */
-  {
-    int status;
+    while (options.get_pid() != 0)              /* while server isn't stopped */
+    {
+      int status;
 
-    status= pthread_cond_timedwait(&COND_instance_stopped,
-                                   &LOCK_instance,
-                                   &timeout);
-    if (status == ETIMEDOUT || status == ETIME)
-      break;
-  }
+      status= pthread_cond_timedwait(&COND_instance_stopped,
+                                     &LOCK_instance,
+                                     &timeout);
+      if (status == ETIMEDOUT || status == ETIME)
+        break;
+    }
 
-  pthread_mutex_unlock(&LOCK_instance);
+    pthread_mutex_unlock(&LOCK_instance);
 
-  kill_instance(SIGKILL);
+    kill_instance(SIGKILL);
 
-  return 0;
+    return 0;
+  }
 
   return ER_INSTANCE_IS_NOT_STARTED;
-err:
-  return ER_STOP_INSTANCE;
 }
 
 #ifdef __WIN__

server-tools/instance-manager/messages.cc

@@ -48,8 +48,8 @@ static const char *mysqld_error_message(unsigned sql_errno)
   case ER_BAD_INSTANCE_NAME:
     return "Bad instance name. Check that the instance with such a name exists";
   case ER_INSTANCE_IS_NOT_STARTED:
-    return "Cannot stop instance. Perhaps the instance is not started, or was started"
-            "manually, so IM cannot find the pidfile.";
+    return "Cannot stop instance. Perhaps the instance is not started, or was"
+           " started manually, so IM cannot find the pidfile.";
   case ER_INSTANCE_ALREADY_STARTED:
     return "The instance is already started";
   case ER_CANNOT_START_INSTANCE:
@@ -67,7 +67,7 @@ static const char *mysqld_error_message(unsigned sql_errno)
     return "Cannot open log file";
   case ER_GUESS_LOGFILE:
     return "Cannot guess the log filename. Try specifying full log name"
-           "in the instance options";
+           " in the instance options";
   case ER_ACCESS_OPTION_FILE:
     return "Cannot open the option file to edit. Check permissions";
   default: