/**
* 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 chain that can 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++ << 16);
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);
ptr = GWBUF_DATA(orig);
*ptr++ = (newlength + 1) & 0xff;
*ptr++ = ((newlength + 1) >> 8) & 0xff;
*ptr++ = ((newlength + 1) >> 16) & 0xff;
}
/**
* Trim bytes from the end of a GWBUF structure that may be the first
* in a list. If the buffer has n_bytes or less then it will be freed and
* the next buffer in the list will be returned, or if none, NULL.
*
* @param head The buffer to trim
* @param n_bytes The number of bytes to trim off
* @return The buffer chain or NULL if buffer chain now empty
*/
GWBUF *
gwbuf_rtrim(GWBUF *head, unsigned int n_bytes)
{
GWBUF *rval = head;
CHK_GWBUF(head);
GWBUF_RTRIM(head, n_bytes);
CHK_GWBUF(head);
if (GWBUF_EMPTY(head))
{
rval = head->next;
gwbuf_free(head);
}
return rval;
}
/**
*
* @param my_instance
* @param my_session
* @param buffer
* @return
*/
GWBUF* clone_query(TEE_INSTANCE* my_instance, TEE_SESSION* my_session, GWBUF* buffer)
{
GWBUF* clone = NULL;
int length, residual = 0;
char* ptr;
if (my_session->branch_session &&
my_session->branch_session->state == SESSION_STATE_ROUTER_READY)
{
if (my_session->residual)
{
clone = gwbuf_clone_all(buffer);
if (my_session->residual < GWBUF_LENGTH(clone))
{
GWBUF_RTRIM(clone, GWBUF_LENGTH(clone) - residual);
}
my_session->residual -= GWBUF_LENGTH(clone);
if (my_session->residual < 0)
{
my_session->residual = 0;
}
}
else if (my_session->active && (ptr = modutil_get_SQL(buffer)) != NULL)
{
if ((my_instance->match == NULL ||
regexec(&my_instance->re, ptr, 0, NULL, 0) == 0) &&
(my_instance->nomatch == NULL ||
regexec(&my_instance->nore,ptr,0,NULL, 0) != 0))
{
length = modutil_MySQL_query_len(buffer, &residual);
clone = gwbuf_clone_all(buffer);
my_session->residual = residual;
}
free(ptr);
}
else if (packet_is_required(buffer))
{
clone = gwbuf_clone_all(buffer);
}
}
return clone;
}
