Fix phpGH-15102: use after free on persistent connection renewal.

simplifying the workflow by just using PQreset which renew internally
the connection and let the existing checks do the rest, process id
 should still be different.

Author: devnexen

ext/pgsql/pgsql.c

@@ -682,7 +682,6 @@ static void php_pgsql_do_connect(INTERNAL_FUNCTION_PARAMETERS, int persistent)
 
 		/* try to find if we already have this link in our persistent list */
 		if ((le = zend_hash_find_ptr(&EG(persistent_list), str.s)) == NULL) {  /* we don't */
-newpconn:
 			if (PGG(max_links) != -1 && PGG(num_links) >= PGG(max_links)) {
 				php_error_docref(NULL, E_WARNING,
 								 "Cannot create new link. Too many open links (" ZEND_LONG_FMT ")", PGG(num_links));
@@ -720,11 +719,7 @@ static void php_pgsql_do_connect(INTERNAL_FUNCTION_PARAMETERS, int persistent)
 				while ((pg_result = PQgetResult(le->ptr))) {
 					PQclear(pg_result);
 				}
-				PQfinish(le->ptr);
-				le->ptr = NULL;
-				PGG(num_links)--;
-				PGG(num_persistent)--;
-				goto newpconn;
+				PQreset(le->ptr);
 			}
 			/* ensure that the link did not die */
 			if (PGG(auto_reset_persistent) & 1) {