From 55513cc99866ae7125ed786451a7dc37ee5a28d3 Mon Sep 17 00:00:00 2001
From: Markus Makela <markus.makela@mariadb.com>
Date: Sun, 22 Mar 2015 07:44:14 +0200
Subject: [PATCH] Improved modutil_get_complete_packets to only allocate a
 single buffer.

---
 server/core/modutil.c                   | 42 +++++++++++++++++++++++--
 server/modules/protocol/mysql_backend.c | 25 +++++++++++++++
 2 files changed, 64 insertions(+), 3 deletions(-)

diff --git a/server/core/modutil.c b/server/core/modutil.c
index 6362d70a0..f4a0a4e4e 100644
--- a/server/core/modutil.c
+++ b/server/core/modutil.c
@@ -537,12 +537,48 @@ return_packetbuf:
  */
 GWBUF* modutil_get_complete_packets(GWBUF** p_readbuf)
 {
-    GWBUF *buff = NULL, *packet = NULL;
+    GWBUF *buff = NULL, *packet;
+    uint8_t *ptr,*end;
+    unsigned int len,total = 0;
+
+    if(p_readbuf == NULL || (*p_readbuf) == NULL ||
+       gwbuf_length(*p_readbuf) < 3)
+	return NULL;
+
+    packet = *p_readbuf;
+    ptr = (uint8_t*)packet->start;
+    end = (uint8_t*)packet->end;
+    len = gw_mysql_get_byte3(ptr) + 4;
     
-    while((packet = modutil_get_next_MySQL_packet(p_readbuf)) != NULL)
+    if(ptr + len >= end)
+	return NULL;
+
+    while(ptr + len < end)
     {
-        buff = gwbuf_append(buff,packet);
+	ptr += len;
+	total += len;
+	len = gw_mysql_get_byte3(ptr) + 4;
     }
+
+    /** Full packets only, return original */
+    if(total == gwbuf_length(packet))
+	return packet;
+
+    /** The next packet is a partial, split into complete and partial packets */
+    total -= len;
+
+    if(buff = gwbuf_alloc(total))
+    {
+	skygw_log_write(LOGFILE_ERROR,
+		 "Error: Failed to allocate new buffer "
+		" of %d bytes while splitting buffer"
+		" into complete packets.",
+		 total);
+	return NULL;
+    }
+    
+    memcpy(buff->start,packet->start,total);
+    gwbuf_consume(*p_readbuf,total);
     
     return buff;
 }
diff --git a/server/modules/protocol/mysql_backend.c b/server/modules/protocol/mysql_backend.c
index 2096f937d..7fff6871f 100644
--- a/server/modules/protocol/mysql_backend.c
+++ b/server/modules/protocol/mysql_backend.c
@@ -493,6 +493,31 @@ static int gw_read_backend_event(DCB *dcb) {
                         ss_dassert(read_buffer != NULL || dcb->dcb_readqueue != NULL);
                 }
 
+		read_buffer = gwbuf_append(read_buffer,dcb->dcb_readqueue);
+		nbytes_read = gwbuf_length(read_buffer);
+		
+		if (nbytes_read < 3)
+		{
+		    dcb->dcb_readqueue = gwbuf_append(dcb->dcb_readqueue, read_buffer);
+		    rc = 0;
+		    goto return_rc;
+		}
+
+                {
+		    GWBUF *tmp = modutil_get_complete_packets(&read_buffer);
+		    
+		    if(tmp == NULL)
+		    {
+			dcb->dcb_readqueue = gwbuf_append(dcb->dcb_readqueue, read_buffer);
+			rc = 0;
+			goto return_rc;
+			
+		    }
+		    
+		    dcb->dcb_readqueue = read_buffer;
+		    read_buffer = tmp;
+		}
+
                 /** 
                  * If protocol has session command set, concatenate whole 
                  * response into one buffer.