From 4cf5b3293f02f8bb44d49422d8f18b95710d266c Mon Sep 17 00:00:00 2001
From: vraatikka <vilho.raatikka@skysql.com>
Date: Tue, 17 Sep 2013 15:10:16 +0300
Subject: [PATCH] Added check routine for gw_buffer. Only effective in debug
 build.

---
 server/core/buffer.c | 16 +++++++++-------
 utils/skygw_debug.h  |  7 ++++++-
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/server/core/buffer.c b/server/core/buffer.c
index 09b165ddd..505f3e039 100644
--- a/server/core/buffer.c
+++ b/server/core/buffer.c
@@ -37,7 +37,7 @@
 #include <stdlib.h>
 #include <buffer.h>
 #include <atomic.h>
-
+#include <skygw_debug.h>
 
 /**
  * Allocate a new gateway buffer structure of size bytes.
@@ -82,7 +82,7 @@ SHARED_BUF	*sbuf;
 	rval->sbuf = sbuf;
 	rval->next = NULL;
 	rval->command = 0;
-
+        CHK_GWBUF(rval);
 	return rval;
 }
 
@@ -95,9 +95,10 @@ void
 gwbuf_free(GWBUF *buf)
 {
 	atomic_add(&buf->sbuf->refcount, -1);
+        CHK_GWBUF(buf);
 	if (buf->sbuf->refcount == 0)
 	{
-		free(buf->sbuf->data);
+                free(buf->sbuf->data);
 		free(buf->sbuf);
 	}
 	free(buf);
@@ -129,7 +130,7 @@ GWBUF	*rval;
 	rval->end = buf->end;
 	rval->next = NULL;
 	rval->command = buf->command;
-
+        CHK_GWBUF(rval);
 	return rval;
 }
 /**
@@ -146,9 +147,10 @@ GWBUF	*
 gwbuf_append(GWBUF *head, GWBUF *tail)
 {
 GWBUF	*ptr = head;
-
+        
 	if (!head)
 		return tail;
+        CHK_GWBUF(head);
 	while (ptr->next)
 	{
 		ptr = ptr->next;
@@ -177,7 +179,7 @@ GWBUF *
 gwbuf_consume(GWBUF *head, unsigned int length)
 {
 GWBUF *rval = head;
-
+        CHK_GWBUF(head);
 	GWBUF_CONSUME(head, length);
 	if (GWBUF_EMPTY(head))
 	{
@@ -197,7 +199,7 @@ unsigned int
 gwbuf_length(GWBUF *head)
 {
 int	rval = 0;
-
+        CHK_GWBUF(head);
 	while (head)
 	{
 		rval += GWBUF_LENGTH(head);
diff --git a/utils/skygw_debug.h b/utils/skygw_debug.h
index 9dd218bbb..9d8ed6909 100644
--- a/utils/skygw_debug.h
+++ b/utils/skygw_debug.h
@@ -16,7 +16,7 @@
  * Copyright SkySQL Ab 2013
  */
 
-
+#include <stdio.h>
 #include <assert.h>
 
 #define __USE_UNIX98 1 
@@ -360,6 +360,11 @@ typedef enum skygw_chk_t {
                             "Session under- or overflow");              \
     }
 
+#define CHK_GWBUF(b) {                                                  \
+            ss_info_dassert(((b)->start <= (b)->end),                   \
+                            "gwbuf start has passed the endpoint");     \
+    }
+
 #if defined(SS_DEBUG)
 bool conn_open[1024];
 #endif