Fix a problem with cursors, which did not happen with unbuffered PS for

some reason. Double free of the data, which led to valgrind warnigns.
The fix actually optimizes the code in this cases because the old code
used copy_ctor while the new one skips it because it is not needed.
Transferring data ownership and nulling works best, for PS where we
always copy the string from the result set, unlike the text protocol.

4 files changed, 53 insertions, 23 deletions

diff --git a/ext/mysqlnd/mysqlnd_palloc.c b/ext/mysqlnd/mysqlnd_palloc.c
index ca945c1901..1b035ed365 100644
--- a/ext/mysqlnd/mysqlnd_palloc.c
+++ b/ext/mysqlnd/mysqlnd_palloc.c
@@ -497,9 +497,14 @@ void mysqlnd_palloc_zval_ptr_dtor(zval **zv, MYSQLND_THD_ZVAL_PCACHE * const thd
 		*(thd_cache->gc_list.last_added++) = (mysqlnd_zval *)*zv;
 		UNLOCK_PCACHE(cache);
 	} else {
+		DBG_INF("No user reference");
 		/* No user reference */
 		if (((mysqlnd_zval *)*zv)->point_type == MYSQLND_POINTS_EXT_BUFFER) {
-			/* PS are here and also in Unicode mode, for non-binary  */
+			DBG_INF("Points to external buffer. Calling zval_dtor");
+			/*
+			  PS are here
+			  Unicode mode goes also here if the column is not binary but a text
+			*/
 			zval_dtor(*zv);
 		}
 		LOCK_PCACHE(cache);
diff --git a/ext/mysqlnd/mysqlnd_ps.c b/ext/mysqlnd/mysqlnd_ps.c
index f406fb8068..3427157617 100644
--- a/ext/mysqlnd/mysqlnd_ps.c
+++ b/ext/mysqlnd/mysqlnd_ps.c
@@ -536,12 +536,14 @@ mysqlnd_stmt_execute_parse_response(MYSQLND_STMT * const stmt TSRMLS_DC)
 						stmt->upsert_status.server_status & SERVER_STATUS_CURSOR_EXISTS);
 
 			if (stmt->upsert_status.server_status & SERVER_STATUS_CURSOR_EXISTS) {
+				DBG_INF("cursor exists");
 				stmt->cursor_exists = TRUE;
 				CONN_SET_STATE(conn, CONN_READY);
 				/* Only cursor read */
 				stmt->default_rset_handler = stmt->m->use_result;
 				DBG_INF("use_result");
 			} else if (stmt->flags & CURSOR_TYPE_READ_ONLY) {
+				DBG_INF("asked for cursor but got none");
 				/*
 				  We have asked for CURSOR but got no cursor, because the condition
 				  above is not fulfilled. Then...
@@ -556,6 +558,7 @@ mysqlnd_stmt_execute_parse_response(MYSQLND_STMT * const stmt TSRMLS_DC)
 				stmt->default_rset_handler = stmt->m->store_result;
 				DBG_INF("store_result");
 			} else {
+				DBG_INF("no cursor");
 				/* preferred is unbuffered read */
 				stmt->default_rset_handler = stmt->m->use_result;
 				DBG_INF("use_result");
@@ -853,15 +856,10 @@ mysqlnd_stmt_fetch_row_unbuffered(MYSQLND_RES *result, void *param, unsigned int
 					  stmt->result_bind[i].zv has been already destructed
 					  in mysqlnd_unbuffered_free_last_data()
 					*/
-
 #ifndef WE_DONT_COPY_IN_BUFFERED_AND_UNBUFFERED_BECAUSEOF_IS_REF
 					zval_dtor(stmt->result_bind[i].zv);
 #endif
 					if (IS_NULL != (Z_TYPE_P(stmt->result_bind[i].zv) = Z_TYPE_P(data)) ) {
-						stmt->result_bind[i].zv->value = data->value;
-#ifndef WE_DONT_COPY_IN_BUFFERED_AND_UNBUFFERED_BECAUSEOF_IS_REF
-						zval_copy_ctor(stmt->result_bind[i].zv);
-#endif						
 						if (
 							(Z_TYPE_P(data) == IS_STRING
 #if PHP_MAJOR_VERSION >= 6
@@ -872,6 +870,9 @@ mysqlnd_stmt_fetch_row_unbuffered(MYSQLND_RES *result, void *param, unsigned int
 						{
 							result->meta->fields[i].max_length = Z_STRLEN_P(data);
 						}
+						stmt->result_bind[i].zv->value = data->value;
+						// copied data, thus also the ownership. Thus null data
+						ZVAL_NULL(data);
 					}
 				}
 			}
@@ -888,14 +889,15 @@ mysqlnd_stmt_fetch_row_unbuffered(MYSQLND_RES *result, void *param, unsigned int
 			row_packet->row_buffer = NULL;
 		}
 	} else if (ret == FAIL) {
+		*fetched_anything = FALSE;
 		if (row_packet->error_info.error_no) {
 			stmt->conn->error_info = row_packet->error_info; 
 			stmt->error_info = row_packet->error_info; 
 		}
-		*fetched_anything = FALSE;
 		CONN_SET_STATE(result->conn, CONN_READY);
 		result->unbuf->eof_reached = TRUE; /* so next time we won't get an error */	
 	} else if (row_packet->eof) {
+		*fetched_anything = FALSE;
 		DBG_INF("EOF");
 		/* Mark the connection as usable again */
 		result->unbuf->eof_reached = TRUE;
@@ -910,7 +912,6 @@ mysqlnd_stmt_fetch_row_unbuffered(MYSQLND_RES *result, void *param, unsigned int
 		} else {
 			CONN_SET_STATE(result->conn, CONN_READY);
 		}
-		*fetched_anything = FALSE;
 	}
 
 	DBG_INF_FMT("ret=%s fetched_anything=%d", ret == PASS? "PASS":"FAIL", *fetched_anything);
@@ -944,7 +945,8 @@ MYSQLND_METHOD(mysqlnd_stmt, use_result)(MYSQLND_STMT *stmt TSRMLS_DC)
 
 	MYSQLND_INC_CONN_STATISTIC(&stmt->conn->stats, STAT_PS_UNBUFFERED_SETS);
 	result = stmt->result;
-	
+
+	DBG_INF_FMT("%scursor exists", stmt->cursor_exists? "":"no ");
 	result->m.use_result(stmt->result, TRUE TSRMLS_CC);
 	result->m.fetch_row	= stmt->cursor_exists? mysqlnd_fetch_stmt_row_cursor:
 											   mysqlnd_stmt_fetch_row_unbuffered;
@@ -1002,15 +1004,19 @@ mysqlnd_fetch_stmt_row_cursor(MYSQLND_RES *result, void *param, unsigned int fla
 
 	if (PASS == (ret = PACKET_READ(row_packet, result->conn)) && !row_packet->eof) {
 		unsigned int i, field_count = result->field_count;
-		mysqlnd_unbuffered_free_last_data(result TSRMLS_CC);
+		result->unbuf->row_count++;
+		*fetched_anything = TRUE;
 
-		result->unbuf->last_row_data = row_packet->fields;
-		result->unbuf->last_row_buffer = row_packet->row_buffer;
+		DBG_INF_FMT("skip_extraction=%d", row_packet->skip_extraction); 
+		if (!row_packet->skip_extraction) {
+			mysqlnd_unbuffered_free_last_data(result TSRMLS_CC);
 
+			DBG_INF("extracting data");
+			result->unbuf->last_row_data = row_packet->fields;
+			result->unbuf->last_row_buffer = row_packet->row_buffer;
+			row_packet->fields = NULL;
+			row_packet->row_buffer = NULL;
 
-		row_packet->fields = NULL;
-		row_packet->row_buffer = NULL;
-		if (!row_packet->skip_extraction) {
 			result->m.row_decoder(result->unbuf->last_row_buffer,
 								  result->unbuf->last_row_data,
 								  row_packet->field_count,
@@ -1025,12 +1031,12 @@ mysqlnd_fetch_stmt_row_cursor(MYSQLND_RES *result, void *param, unsigned int fla
 					  stmt->result_bind[i].zv has been already destructed
 					  in mysqlnd_unbuffered_free_last_data()
 					*/
-					DBG_INF_FMT("i=%d type=%d", i, Z_TYPE_P(stmt->result_bind[i].zv));
-					if (IS_NULL != (Z_TYPE_P(stmt->result_bind[i].zv) = Z_TYPE_P(data)) ) {
-						stmt->result_bind[i].zv->value = data->value;
-#ifdef WE_DONT_COPY_IN_BUFFERED_AND_UNBUFFERED_BECAUSEOF_IS_REF
-						zval_copy_ctor(stmt->result_bind[i].zv);
+#ifndef WE_DONT_COPY_IN_BUFFERED_AND_UNBUFFERED_BECAUSEOF_IS_REF
+					zval_dtor(stmt->result_bind[i].zv);
 #endif
+					DBG_INF_FMT("i=%d bound_var=%p type=%d refc=%u", i, stmt->result_bind[i].zv,
+								Z_TYPE_P(data), Z_REFCOUNT_P(stmt->result_bind[i].zv));
+					if (IS_NULL != (Z_TYPE_P(stmt->result_bind[i].zv) = Z_TYPE_P(data))) {
 						if ((Z_TYPE_P(data) == IS_STRING
 #if PHP_MAJOR_VERSION >= 6
 							|| Z_TYPE_P(data) == IS_UNICODE
@@ -1040,12 +1046,23 @@ mysqlnd_fetch_stmt_row_cursor(MYSQLND_RES *result, void *param, unsigned int fla
 						{
 							result->meta->fields[i].max_length = Z_STRLEN_P(data);
 						}
+						stmt->result_bind[i].zv->value = data->value;
+						// copied data, thus also the ownership. Thus null data
+						ZVAL_NULL(data);
 					}
 				}
 			}
+		} else {
+			DBG_INF("skipping extraction");
+			/*
+			  Data has been allocated and usually mysqlnd_unbuffered_free_last_data()
+			  frees it but we can't call this function as it will cause problems with
+			  the bound variables. Thus we need to do part of what it does or Zend will
+			  report leaks.
+			*/
+			row_packet->row_buffer->free_chunk(row_packet->row_buffer, TRUE TSRMLS_CC);
+			row_packet->row_buffer = NULL;
 		}
-		result->unbuf->row_count++;
-		*fetched_anything = TRUE;
 		/* We asked for one row, the next one should be EOF, eat it */
 		ret = PACKET_READ(row_packet, result->conn);
 		if (row_packet->row_buffer) {
@@ -1491,7 +1508,8 @@ MYSQLND_METHOD(mysqlnd_stmt, bind_result)(MYSQLND_STMT * const stmt,
 		stmt->result_bind = result_bind;
 		for (i = 0; i < stmt->field_count; i++) {
 			/* Prevent from freeing */
-			Z_ADDREF_P(stmt->result_bind[i].zv);		
+			Z_ADDREF_P(stmt->result_bind[i].zv);
+			DBG_INF_FMT("ref of %p = %u", stmt->result_bind[i].zv, Z_REFCOUNT_P(stmt->result_bind[i].zv));
 			/*
 			  Don't update is_ref !!! it's not our job
 			  Otherwise either 009.phpt or mysqli_stmt_bind_result.phpt
diff --git a/ext/mysqlnd/mysqlnd_ps_codec.c b/ext/mysqlnd/mysqlnd_ps_codec.c
index 673523c77c..6fd2e053b2 100644
--- a/ext/mysqlnd/mysqlnd_ps_codec.c
+++ b/ext/mysqlnd/mysqlnd_ps_codec.c
@@ -405,12 +405,14 @@ void ps_fetch_string(zval *zv, const MYSQLND_FIELD * const field,
 	DBG_ENTER("ps_fetch_string");
 	DBG_INF_FMT("len = %lu", length);
 #if PHP_MAJOR_VERSION < 6
+	DBG_INF("copying from the row buffer");
 	ZVAL_STRINGL(zv, (char *)*row, length, 1);	
 #else
 	if (field->charsetnr == MYSQLND_BINARY_CHARSET_NR) {
 		DBG_INF("Binary charset");
 		ZVAL_STRINGL(zv, (char *)*row, length, 1);
 	} else {
+		DBG_INF_FMT("copying from the row buffer");
 		ZVAL_UTF8_STRINGL(zv, (char*)*row, length, ZSTR_DUPLICATE);
 	}
 #endif
diff --git a/ext/mysqlnd/mysqlnd_result.c b/ext/mysqlnd/mysqlnd_result.c
index f791fd0fb5..e161f28854 100644
--- a/ext/mysqlnd/mysqlnd_result.c
+++ b/ext/mysqlnd/mysqlnd_result.c
@@ -143,10 +143,13 @@ void mysqlnd_unbuffered_free_last_data(MYSQLND_RES *result TSRMLS_DC)
 		DBG_VOID_RETURN;
 	}
 
+	DBG_INF_FMT("last_row_data=%p", unbuf->last_row_data);
 	if (unbuf->last_row_data) {
 		unsigned int i, ctor_called_count = 0;
 		zend_bool copy_ctor_called;
 		MYSQLND_STATS *global_stats = result->conn? &result->conn->stats:NULL;
+
+		DBG_INF_FMT("%u columns to free", result->field_count);
 		for (i = 0; i < result->field_count; i++) {
 			mysqlnd_palloc_zval_ptr_dtor(&(unbuf->last_row_data[i]),
 										 result->zval_cache, result->type,
@@ -155,6 +158,7 @@ void mysqlnd_unbuffered_free_last_data(MYSQLND_RES *result TSRMLS_DC)
 				ctor_called_count++;
 			}
 		}
+		DBG_INF_FMT("copy_ctor_called_count=%u", ctor_called_count);
 		/* By using value3 macros we hold a mutex only once, there is no value2 */
 		MYSQLND_INC_CONN_STATISTIC_W_VALUE3(global_stats,
 											STAT_COPY_ON_WRITE_PERFORMED,
@@ -168,6 +172,7 @@ void mysqlnd_unbuffered_free_last_data(MYSQLND_RES *result TSRMLS_DC)
 		unbuf->last_row_data = NULL;
 	}
 	if (unbuf->last_row_buffer) {
+		DBG_INF("Freeing last row buffer");
 		/* Nothing points to this buffer now, free it */
 		unbuf->last_row_buffer->free_chunk(unbuf->last_row_buffer, TRUE TSRMLS_CC);
 		unbuf->last_row_buffer = NULL;