/*%
* Loops through the list of DB instances, attempting to lock
* on the mutex. If successful, the DBI is reserved for use
* and the thread can perform queries against the database.
* If the lock fails, the next one in the list is tried.
* looping continues until a lock is obtained, or until
* the list has been searched dbc_search_limit times.
* This function is only used when the module is compiled for
* multithreaded operation.
*/
static dbinstance_t *
mysql_find_avail_conn(mysql_instance_t *mysql) {
dbinstance_t *dbi = NULL, *head;
int count = 0;
/* get top of list */
head = dbi = DLZ_LIST_HEAD(*(mysql->db));
/* loop through list */
while (count < dbc_search_limit) {
/* try to lock on the mutex */
if (dlz_mutex_trylock(&dbi->lock) == 0)
return (dbi); /* success, return the DBI for use. */
/* not successful, keep trying */
dbi = DLZ_LIST_NEXT(dbi, link);
/* check to see if we have gone to the top of the list. */
if (dbi == NULL) {
count++;
dbi = head;
}
}
mysql->log(ISC_LOG_INFO,
"MySQL module unable to find available connection "
"after searching %d times", count);
return (NULL);
}
void
destroy_querylist(query_list_t **querylist) {
query_segment_t *tseg = NULL;
query_segment_t *nseg = NULL;
/* if query list is null, nothing to do */
if (*querylist == NULL)
return;
/* start at the top of the list */
nseg = DLZ_LIST_HEAD(**querylist);
while (nseg != NULL) { /* loop, until end of list */
tseg = nseg;
/*
* free the query segment's text string but only if it
* was really a query segment, and not a pointer to
* %zone%, or %record%, or %client%
*/
if (tseg->cmd != NULL && tseg->direct == ISC_TRUE)
free(tseg->cmd);
/* get the next query segment, before we destroy this one. */
nseg = DLZ_LIST_NEXT(nseg, link);
/* deallocate this query segment. */
free(tseg);
}
/* deallocate the query segment list */
free(*querylist);
}
/*%
* build a query string from query segments, and dynamic segments
* dynamic segments replace where the tokens %zone%, %record%, %client%
* used to be in our queries from named.conf
*/
char *
build_querystring(query_list_t *querylist) {
query_segment_t *tseg = NULL;
unsigned int length = 0;
char *qs = NULL;
/* start at the top of the list */
tseg = DLZ_LIST_HEAD(*querylist);
while (tseg != NULL) {
/*
* if this is a query segment, use the
* precalculated string length
*/
if (tseg->direct == ISC_TRUE)
length += tseg->strlen;
else /* calculate string length for dynamic segments. */
length += strlen(* (char**) tseg->cmd);
/* get the next segment */
tseg = DLZ_LIST_NEXT(tseg, link);
}
/* allocate memory for the string */
qs = malloc(length + 1);
/* couldn't allocate memory, We need more ram! */
if (qs == NULL)
return (NULL);
*qs = 0;
/* start at the top of the list again */
tseg = DLZ_LIST_HEAD(*querylist);
while (tseg != NULL) {
if (tseg->direct == ISC_TRUE)
/* query segments */
strcat(qs, tseg->cmd);
else
/* dynamic segments */
strcat(qs, * (char**) tseg->cmd);
/* get the next segment */
tseg = DLZ_LIST_NEXT(tseg, link);
}
return (qs);
}
/*%
* Properly cleans up a list of database instances.
* This function is only used when the module is compiled for
* multithreaded operation.
*/
static void
mysql_destroy_dblist(db_list_t *dblist) {
dbinstance_t *ndbi = NULL;
dbinstance_t *dbi = NULL;
ndbi = DLZ_LIST_HEAD(*dblist);
while (ndbi != NULL) {
dbi = ndbi;
ndbi = DLZ_LIST_NEXT(dbi, link);
mysql_destroy(dbi);
}
/* release memory for the list structure */
free(dblist);
}
/*%
* Properly cleans up a list of database instances.
* This function is only used when the driver is compiled for
* multithreaded operation.
*/
static void
ldap_destroy_dblist(db_list_t *dblist) {
dbinstance_t *ndbi = NULL;
dbinstance_t *dbi = NULL;
/* get the first DBI in the list */
ndbi = DLZ_LIST_HEAD(*dblist);
/* loop through the list */
while (ndbi != NULL) {
dbi = ndbi;
/* get the next DBI in the list */
ndbi = DLZ_LIST_NEXT(dbi, link);
/* release DB connection */
if (dbi->dbconn != NULL)
ldap_unbind_s((LDAP *) dbi->dbconn);
/* release all memory that comprised a DBI */
destroy_dbinstance(dbi);
}
/* release memory for the list structure */
free(dblist);
}
