From 31cda5ad65a2ad7095693cf72f193a4cf4ac05ef Mon Sep 17 00:00:00 2001
From: Massimiliano Pinto <massimiliano.pinto@skysql.com>
Date: Mon, 2 Sep 2013 10:26:34 +0200
Subject: [PATCH] Added session refcount in session.h

The refcount is incremented in dcb_connect and in mysql_client.c after session_alloc
---
 server/core/dcb.c                      |  7 ++++++-
 server/core/session.c                  | 14 +++++++++++---
 server/include/session.h               |  5 ++++-
 server/modules/protocol/mysql_client.c |  2 ++
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/server/core/dcb.c b/server/core/dcb.c
index de7267aaf..7d91d514a 100644
--- a/server/core/dcb.c
+++ b/server/core/dcb.c
@@ -39,7 +39,8 @@
  *					for handling backend asynchronous protocol connection
  *					and a generic lock for backend authentication
  * 16/07/2013	Massimiliano Pinto	Added command type for dcb
- * 23/07/13	Mark Riddoch		Tidy up logging
+ * 23/07/2013	Mark Riddoch		Tidy up logging
+ * 02/09/2013	Massimiliano Pinto	Added session refcount
  *
  * @endverbatim
  */
@@ -314,6 +315,8 @@ GWPROTOCOL	*funcs;
 	memcpy(&(dcb->func), funcs, sizeof(GWPROTOCOL));
 	dcb->session = session;
 
+	atomic_add(&dcb->session->refcount, 1);
+
 	if ((dcb->fd = dcb->func.connect(dcb, server, session)) == -1)
 	{
 		dcb_final_free(dcb);
@@ -646,6 +649,8 @@ dcb_close(DCB *dcb)
                                         pthread_self());
                         }
 		}
+	}
+	if (dcb->session) {
 		session_free(dcb->session);
                 skygw_log_write_flush(
                         LOGFILE_TRACE,
diff --git a/server/core/session.c b/server/core/session.c
index cb72ea0bd..ce0b77782 100644
--- a/server/core/session.c
+++ b/server/core/session.c
@@ -22,8 +22,9 @@
  * @verbatim
  * Revision History
  *
- * Date		Who		Description
- * 17/06/13	Mark Riddoch	Initial implementation
+ * Date		Who			Description
+ * 17/06/13	Mark Riddoch		Initial implementation
+ * 02/09/13	Massimiliano Pinto	Added session refcounter
  *
  * @endverbatim
  */
@@ -75,6 +76,9 @@ session_alloc(SERVICE *service, DCB *client)
                         strerror(eno));
 		return NULL;
         }
+
+	session->refcount = 0;
+
         session->ses_chk_top = CHK_NUM_SESSION;
         session->ses_chk_tail = CHK_NUM_SESSION;
         spinlock_init(&session->ses_lock);
@@ -149,8 +153,12 @@ SESSION *ptr;
 	}
 	spinlock_release(&session_spin);
 	atomic_add(&session->service->stats.n_current, -1);
+
 	/* Clean up session and free the memory */
-	free(session);
+	if (atomic_add(&session->refcount, -1) == 1)
+	{
+		free(session);
+	}
 }
 
 /**
diff --git a/server/include/session.h b/server/include/session.h
index e0de9a303..df25f8dd8 100644
--- a/server/include/session.h
+++ b/server/include/session.h
@@ -29,7 +29,9 @@
  * 14-06-2013	Massimiliano Pinto	Added void *data to session
  *					for session specific data
  * 01-07-2013	Massimiliano Pinto	Removed backends pointer
-					from struct session
+ *					from struct session
+ * 02-09-2013	Massimiliano Pinto	Added session ref counter
+ *
  * @endverbatim
  */
 #include <time.h>
@@ -81,6 +83,7 @@ typedef struct session {
 	struct service	*service;	/**< The service this session is using */
 	struct session	*next;		/**< Linked list of all sessions */
         skygw_chk_t     ses_chk_tail;
+	int		refcount;	/**< Reference count on the session */
 } SESSION;
 
 #define SESSION_PROTOCOL(x, type)	DCB_PROTOCOL((x)->client, type)
diff --git a/server/modules/protocol/mysql_client.c b/server/modules/protocol/mysql_client.c
index e123e0cf8..d2ccb0a8f 100644
--- a/server/modules/protocol/mysql_client.c
+++ b/server/modules/protocol/mysql_client.c
@@ -27,6 +27,7 @@
  * 14/06/2013	Mark Riddoch		Initial version
  * 17/06/2013	Massimiliano Pinto	Added Client To Gateway routines
  * 24/06/2013	Massimiliano Pinto	Added: fetch passwords from service users' hashtable
+ * 02/09/2013	Massimiliano Pinto	Added: session refcount
  */
 #include <skygw_utils.h>
 #include <log_manager.h>
@@ -587,6 +588,7 @@ int gw_read_client_event(DCB* dcb) {
                         //write to client mysql AUTH_OK packet, packet n. is 2
                         // start a new session, and connect to backends
                         session = session_alloc(dcb->service, dcb);
+			atomic_add(&dcb->session->refcount, 1);
                         CHK_SESSION(session);
                         ss_dassert(session->state != SESSION_STATE_ALLOC);
                         protocol->state = MYSQL_IDLE;