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Support for multipacket statements

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Remove double free in cloned DCB's
This commit is contained in:
Mark Riddoch
2014-06-24 17:59:29 +01:00
parent e650930487
commit a652e875b5
6 changed files with 108 additions and 12 deletions
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21
server/core/buffer.c
View File

@ -31,6 +31,7 @@
* 10/06/13 Mark Riddoch Initial implementation
* 11/07/13 Mark Riddoch Add reference count mechanism
* 16/07/2013 Massimiliano Pinto Added command type to gwbuf struct
* 24/06/2014 Mark Riddoch Addition of gwbuf_trim
*
* @endverbatim
*/
@ -297,6 +298,26 @@ int rval = 0;
return rval;
}
/**
* Trim bytes form the end of a GWBUF structure
*
* @param buf The buffer to trim
* @param nbytes The number of bytes to trim off
* @return The buffer chain
*/
GWBUF *
gwbuf_trim(GWBUF *buf, unsigned int n_bytes)
{
if (GWBUF_LENGTH(buf) <= n_bytes)
{
gwbuf_consume(buf, GWBUF_LENGTH(buf));
return NULL;
}
buf->end -= n_bytes;
return buf;
}
bool gwbuf_set_type(
GWBUF* buf,
gwbuf_type_t type)

2
server/core/dcb.c
View File

@ -347,7 +347,7 @@ DCB_CALLBACK *cb;
}
}
if (dcb->protocol != NULL)
if (dcb->protocol && ((dcb->flags & DCBF_CLONE) ==0))
free(dcb->protocol);
if (dcb->data && ((dcb->flags & DCBF_CLONE) ==0))
free(dcb->data);

52
server/core/modutil.c
View File

@ -57,9 +57,12 @@ unsigned char *ptr;
* 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 data
* @param length Length of the SQL query data
* @return True if the packet is a COM_QUERY packet
*/
int
@ -79,7 +82,54 @@ 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)
{
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 = 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)
{

5
server/include/buffer.h
View File

@ -94,9 +94,9 @@ typedef struct gwbuf {
#define GWBUF_EMPTY(b) ((b)->start == (b)->end)
/*< Consume a number of bytes in the buffer */
#define GWBUF_CONSUME(b, bytes) (b)->start += bytes
#define GWBUF_CONSUME(b, bytes) (b)->start += (bytes)
#define GWBUF_RTRIM(b, bytes) (b)->end -= bytes
#define GWBUF_RTRIM(b, bytes) (b)->end -= (bytes)
#define GWBUF_TYPE(b) (b)->gwbuf_type
/*<
@ -107,6 +107,7 @@ extern void gwbuf_free(GWBUF *buf);
extern GWBUF *gwbuf_clone(GWBUF *buf);
extern GWBUF *gwbuf_append(GWBUF *head, GWBUF *tail);
extern GWBUF *gwbuf_consume(GWBUF *head, unsigned int length);
extern GWBUF *gwbuf_trim(GWBUF *head, unsigned int length);
extern unsigned int gwbuf_length(GWBUF *head);
extern GWBUF *gwbuf_clone_portion(GWBUF *head, size_t offset, size_t len);
extern GWBUF *gwbuf_clone_transform(GWBUF *head, gwbuf_type_t type);

2
server/include/modutil.h
View File

@ -26,6 +26,7 @@
*
* Date Who Description
* 04/06/14 Mark Riddoch Initial implementation
* 24/06/14 Mark Riddoch Add modutil_MySQL_Query to enable multipacket queries
*
* @endverbatim
*/
@ -33,5 +34,6 @@
extern int modutil_is_SQL(GWBUF *);
extern int modutil_extract_SQL(GWBUF *, char **, int *);
extern int modutil_MySQL_Query(GWBUF *, char **, int *, int *);
extern GWBUF *modutil_replace_SQL(GWBUF *, char *);
#endif

38
server/modules/filter/tee.c
View File

@ -39,6 +39,7 @@
*
* Date Who Description
* 20/06/2014 Mark Riddoch Initial implementation
* 24/06/2014 Mark Riddoch Addition of support for multi-packet queries
*
*/
#include <stdio.h>
@ -113,11 +114,12 @@ typedef struct {
* It also holds the file descriptor to which queries are written.
*/
typedef struct {
DOWNSTREAM down;
int active;
DCB *branch_dcb;
SESSION *branch_session;
int n_duped;
DOWNSTREAM down; /* The downstream filter */
int active; /* filter is active? */
DCB *branch_dcb; /* Client DCB for "branch" service */
SESSION *branch_session;/* The branch service session */
int n_duped; /* Number of duplicated querise */
int residual; /* Any outstanding SQL text */
} TEE_SESSION;
/**
@ -274,6 +276,7 @@ char *remote, *userName;
if ((my_session = calloc(1, sizeof(TEE_SESSION))) != NULL)
{
my_session->active = 1;
my_session->residual = 0;
if (my_instance->source
&& (remote = session_get_remote(session)) != NULL)
{
@ -321,7 +324,7 @@ SESSION *bsession;
router->closeSession(router_instance, rsession);
dcb_free(my_session->branch_dcb);
/* No need to free the session, this is done as
* a side effect of closign the client DCB of the
* a side effect of closing the client DCB of the
* session.
*/
}
@ -364,6 +367,14 @@ TEE_SESSION *my_session = (TEE_SESSION *)session;
* query should normally be passed to the downstream component
* (filter or router) in the filter chain.
*
* If my_session->residual is set then duplicate that many bytes
* and send them to the branch.
*
* If my_session->residual is zero then this must be a new request
* Extract the SQL text if possible, match against that text and forward
* the request. If the requets is not contained witin the packet we have
* then set my_session->residual to the number of outstanding bytes
*
* @param instance The filter instance data
* @param session The filter session
* @param queue The query data
@ -374,10 +385,20 @@ routeQuery(FILTER *instance, void *session, GWBUF *queue)
TEE_INSTANCE *my_instance = (TEE_INSTANCE *)instance;
TEE_SESSION *my_session = (TEE_SESSION *)session;
char *ptr;
int length, rval;
int length, rval, residual;
GWBUF *clone = NULL;
if (my_session->active && modutil_extract_SQL(queue, &ptr, &length))
if (my_session->residual)
{
clone = gwbuf_clone(queue);
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 &&
modutil_MySQL_Query(queue, &ptr, &length, &residual))
{
if ((my_instance->match == NULL ||
regexec(&my_instance->re, ptr, 0, NULL, 0) == 0) &&
@ -385,6 +406,7 @@ GWBUF *clone = NULL;
regexec(&my_instance->nore,ptr,0,NULL, 0) != 0))
{
clone = gwbuf_clone(queue);
my_session->residual = residual;
}
}