Initial implementation of the monitor modules and a simple mysql monitor to set

server up or down automatically.

core/monitor.c

@@ -0,0 +1,116 @@
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+
+/**
+ * @file monitor.c  - The monitor module management routines
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date		Who		Description
+ * 08/07/13	Mark Riddoch	Initial implementation
+ *
+ * @endverbatim
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <monitor.h>
+#include <spinlock.h>
+#include <modules.h>
+
+
+static MONITOR	*allMonitors = NULL;
+static SPINLOCK	monLock = SPINLOCK_INIT;
+
+/**
+ * Allocate a new monitor, load the associated module for the monitor
+ * and start execution on the monitor.
+ *
+ * @param name	The name of the monitor module to load
+ * @return 	The newly created monitor
+ */
+MONITOR *
+monitor_alloc(char *name, char *module)
+{
+MONITOR	*mon;
+
+	if ((mon = (MONITOR *)malloc(sizeof(MONITOR))) == NULL)
+	{
+		return NULL;
+	}
+
+	mon->name = strdup(name);
+	mon->module = strdup(module);
+	if ((mon->module = load_module(module, MODULE_MONITOR)) == NULL)
+	{
+		fprintf(stderr, "Unable to load monitor module '%s'\n", name);
+		free(mon->name);
+		free(mon);
+		return NULL;
+	}
+	mon->handle = (*mon->module->startMonitor)();
+
+	spinlock_acquire(&monLock);
+	mon->next = allMonitors;
+	allMonitors = mon;
+	spinlock_release(&monLock);
+
+	return mon;
+}
+
+/**
+ * Free a monitor, first stop the monitor and then remove the monitor from
+ * the chain of monitors and free the memory.
+ *
+ * @param mon	The monitor to free
+ */
+void
+monitor_free(MONITOR *mon)
+{
+MONITOR	*ptr;
+
+	mon->module->stopMonitor(mon->handle);
+	spinlock_acquire(&monLock);
+	if (allMonitors == mon)
+		allMonitors = mon->next;
+	else
+	{
+		ptr = allMonitors;
+		while (ptr->next && ptr->next != mon)
+			ptr = ptr->next;
+		if (ptr->next)
+			ptr->next = mon->next;
+	}
+	spinlock_release(&monLock);
+	free(mon->name);
+	free(mon);
+}
+
+/**
+ * Add a server to a monitor. Simply register the server that needs to be
+ * monitored to the running monitor module.
+ *
+ * @param mon		The Monitor instance
+ * @param server	The Server to add to the monitoring
+ */
+void
+monitorAddServer(MONITOR *mon, SERVER *server)
+{
+	mon->module->registerServer(mon->handle, server);
+}