MaxScale/server/core/modutil.c
VilhoRaatikka 40416d424e Merge branch 'Z3' of https://github.com/skysql/MaxScale into Z3
Conflicts:
	gcov.diff
	server/core/buffer.c
	server/include/buffer.h
	server/modules/routing/readwritesplit/readwritesplit.c
2014-08-29 18:50:32 +03:00

228 lines
6.6 KiB
C

/*
* This file is distributed as part of MaxScale from SkySQL. 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 2014
*/
/**
* @file modutil.c - Implementation of useful routines for modules
*
* @verbatim
* Revision History
*
* Date Who Description
* 04/06/14 Mark Riddoch Initial implementation
*
* @endverbatim
*/
#include <buffer.h>
#include <string.h>
#include <mysql_client_server_protocol.h>
/**
* Check if a GWBUF structure is a MySQL COM_QUERY packet
*
* @param buf Buffer to check
* @return True if GWBUF is a COM_QUERY packet
*/
int
modutil_is_SQL(GWBUF *buf)
{
unsigned char *ptr;
if (GWBUF_LENGTH(buf) < 5)
return 0;
ptr = GWBUF_DATA(buf);
return ptr[4] == 0x03; // COM_QUERY
}
/**
* Extract the SQL portion of a COM_QUERY packet
*
* NB This sets *sql to point into the packet and does not
* allocate any new storage. The string pointed to by *sql is
* not NULL terminated.
*
* This routine is very simplistic and does not deal with SQL text
* that spans multiple buffers.
*
* The length returned is the complete length of the SQL, which may
* be larger than the amount of data in this packet.
*
* @param buf The packet buffer
* @param sql Pointer that is set to point at the SQL data
* @param length Length of the SQL query data
* @return True if the packet is a COM_QUERY packet
*/
int
modutil_extract_SQL(GWBUF *buf, char **sql, int *length)
{
unsigned char *ptr;
if (!modutil_is_SQL(buf))
return 0;
ptr = GWBUF_DATA(buf);
*length = *ptr++;
*length += (*ptr++ << 8);
*length += (*ptr++ << 8);
ptr += 2; // Skip sequence id and COM_QUERY byte
*length = *length - 1;
*sql = (char *)ptr;
return 1;
}
/**
* Extract the SQL portion of a COM_QUERY packet
*
* NB This sets *sql to point into the packet and does not
* allocate any new storage. The string pointed to by *sql is
* not NULL terminated.
*
* The number of bytes pointed to *sql is returned in *length
*
* The remaining number of bytes required for the complete query string
* are returned in *residual
*
* @param buf The packet buffer
* @param sql Pointer that is set to point at the SQL data
* @param length Length of the SQL query data pointed to by sql
* @param residual Any remain part of the query in future packets
* @return True if the packet is a COM_QUERY packet
*/
int
modutil_MySQL_Query(GWBUF *buf, char **sql, int *length, int *residual)
{
unsigned char *ptr;
if (!modutil_is_SQL(buf))
return 0;
ptr = GWBUF_DATA(buf);
*residual = *ptr++;
*residual += (*ptr++ << 8);
*residual += (*ptr++ << 8);
ptr += 2; // Skip sequence id and COM_QUERY byte
*residual = *residual - 1;
*length = GWBUF_LENGTH(buf) - 5;
*residual -= *length;
*sql = (char *)ptr;
return 1;
}
/**
* Replace the contents of a GWBUF with the new SQL statement passed as a text string.
* The routine takes care of the modification needed to the MySQL packet,
* returning a GWBUF chian that cna be used to send the data to a MySQL server
*
* @param orig The original request in a GWBUF
* @param sql The SQL text to replace in the packet
* @return A newly formed GWBUF containing the MySQL packet.
*/
GWBUF *
modutil_replace_SQL(GWBUF *orig, char *sql)
{
unsigned char *ptr;
int length, newlength;
GWBUF *addition;
if (!modutil_is_SQL(orig))
return NULL;
ptr = GWBUF_DATA(orig);
length = *ptr++;
length += (*ptr++ << 8);
length += (*ptr++ << 8);
ptr += 2; // Skip sequence id and COM_QUERY byte
newlength = strlen(sql);
if (length - 1 == newlength)
{
/* New SQL is the same length as old */
memcpy(ptr, sql, newlength);
}
else if (length - 1 > newlength)
{
/* New SQL is shorter */
memcpy(ptr, sql, newlength);
GWBUF_RTRIM(orig, (length - 1) - newlength);
}
else
{
memcpy(ptr, sql, length - 1);
addition = gwbuf_alloc(newlength - (length - 1));
memcpy(GWBUF_DATA(addition), &sql[length - 1], newlength - (length - 1));
ptr = GWBUF_DATA(orig);
*ptr++ = (newlength + 1) & 0xff;
*ptr++ = ((newlength + 1) >> 8) & 0xff;
*ptr++ = ((newlength + 1) >> 16) & 0xff;
orig->next = addition;
}
return orig;
}
/**
* Copy query string from GWBUF buffer to separate memory area.
*
* @param buf GWBUF buffer including the query
*
* @return Plaint text query if the packet type is COM_QUERY. Otherwise return
* a string including the packet type.
*/
char* modutil_get_query(
GWBUF* buf)
{
uint8_t* packet;
mysql_server_cmd_t packet_type;
size_t len;
char* query_str;
packet = GWBUF_DATA(buf);
packet_type = packet[4];
switch (packet_type) {
case MYSQL_COM_QUIT:
len = strlen("[Quit msg]")+1;
if ((query_str = (char *)malloc(len+1)) == NULL)
{
goto retblock;
}
memcpy(query_str, "[Quit msg]", len);
memset(&query_str[len], 0, 1);
break;
case MYSQL_COM_QUERY:
len = MYSQL_GET_PACKET_LEN(packet)-1; /*< distract 1 for packet type byte */
if ((query_str = (char *)malloc(len+1)) == NULL)
{
goto retblock;
}
memcpy(query_str, &packet[5], len);
memset(&query_str[len], 0, 1);
break;
default:
len = strlen(STRPACKETTYPE(packet_type))+1;
if ((query_str = (char *)malloc(len+1)) == NULL)
{
goto retblock;
}
memcpy(query_str, STRPACKETTYPE(packet_type), len);
memset(&query_str[len], 0, 1);
break;
} /*< switch */
retblock:
return query_str;
}