From dee89f856ffba3fcfccf530cd98f4d515bb46728 Mon Sep 17 00:00:00 2001
From: Florian Forster <octo@collectd.org>
Date: Mon, 25 Mar 2013 07:28:36 +0100
Subject: [PATCH] mysql plugin: Call mysql_init() only once.

Apparently, if you call it with a structure allocated by mysql_init()
itself, it leaks memory. Thanks to Yves Mettier for pointing this out!

Fixes Github issue #274.
---
 src/mysql.c | 63 ++++++++++++++++++++++++++++++-------------------------------
 1 file changed, 31 insertions(+), 32 deletions(-)

diff --git a/src/mysql.c b/src/mysql.c
index 6f9efe35..8b3cd210 100644
--- a/src/mysql.c
+++ b/src/mysql.c
@@ -59,7 +59,7 @@ struct mysql_database_s /* {{{ */
 	int   slave_sql_running;
 
 	MYSQL *con;
-	int    state;
+	_Bool  is_connected;
 };
 typedef struct mysql_database_s mysql_database_t; /* }}} */
 
@@ -359,30 +359,31 @@ static int mysql_config (oconfig_item_t *ci) /* {{{ */
 
 static MYSQL *getconnection (mysql_database_t *db)
 {
-	if (db->state != 0)
+	if (db->is_connected)
 	{
-		int err;
-		if ((err = mysql_ping (db->con)) != 0)
-		{
-			WARNING ("mysql_ping failed for %s: %s",
-					(db->instance != NULL)
-					? db->instance
-					: "<legacy>",
-					mysql_error (db->con));
-			db->state = 0;
-		}
-		else
-		{
-			db->state = 1;
+		int status;
+
+		status = mysql_ping (db->con);
+		if (status == 0)
 			return (db->con);
-		}
+
+		WARNING ("mysql plugin: Lost connection to instance \"%s\": %s",
+				(db->instance != NULL)
+				? db->instance
+				: "<legacy>",
+				mysql_error (db->con));
 	}
+	db->is_connected = 0;
 
-	if ((db->con = mysql_init (db->con)) == NULL)
+	if (db->con == NULL)
 	{
-		ERROR ("mysql_init failed: %s", mysql_error (db->con));
-		db->state = 0;
-		return (NULL);
+		db->con = mysql_init (NULL);
+		if (db->con == NULL)
+		{
+			ERROR ("mysql plugin: mysql_init failed: %s",
+					mysql_error (db->con));
+			return (NULL);
+		}
 	}
 
 	if (mysql_real_connect (db->con, db->host, db->user, db->pass,
@@ -393,20 +394,18 @@ static MYSQL *getconnection (mysql_database_t *db)
 				(db->database != NULL) ? db->database : "<none>",
 				(db->host != NULL) ? db->host : "localhost",
 				mysql_error (db->con));
-		db->state = 0;
 		return (NULL);
 	}
-	else
-	{
-		INFO ("mysql plugin: Successfully connected to database %s "
-				"at server %s (server version: %s, protocol version: %d)",
-				(db->database != NULL) ? db->database : "<none>",
-				mysql_get_host_info (db->con),
-				mysql_get_server_info (db->con),
-				mysql_get_proto_info (db->con));
-		db->state = 1;
-		return (db->con);
-	}
+
+	INFO ("mysql plugin: Successfully connected to database %s "
+			"at server %s (server version: %s, protocol version: %d)",
+			(db->database != NULL) ? db->database : "<none>",
+			mysql_get_host_info (db->con),
+			mysql_get_server_info (db->con),
+			mysql_get_proto_info (db->con));
+
+	db->is_connected = 1;
+	return (db->con);
 } /* static MYSQL *getconnection (mysql_database_t *db) */
 
 static void set_host (mysql_database_t *db, char *buf, size_t buflen)
-- 
2.11.0