- Fix Bug #26304 Unexpected data loss when opening dba file

- Correct handling for flatfile handler

2 files changed, 26 insertions, 7 deletions

diff --git a/ext/dba/dba.c b/ext/dba/dba.c
index 72adca6f52..0e996cd3a1 100644
--- a/ext/dba/dba.c
+++ b/ext/dba/dba.c
@@ -648,15 +648,23 @@ static void php_dba_open(INTERNAL_FUNCTION_PARAMETERS, int persistent)
 		case 'c': 
 			modenr = DBA_CREAT; 
 			lock_mode = (lock_flag & DBA_LOCK_CREAT) ? LOCK_EX : 0;
-			if (!lock_mode || !lock_dbf) {
-				file_mode = "a+b";
+			if (lock_mode) {
+				if (lock_dbf) {
+					/* the create/append check will be done on the lock
+					 * when the lib opens the file it is already created
+					 */
+					file_mode = "r+b";       /* read & write, seek 0 */
+					lock_file_mode = "a+b";  /* append */
+				} else {
+					file_mode = "a+b";       /* append */
+					lock_file_mode = "w+b";  /* create/truncate */
+				}
 			} else {
-				/* the create/append check will be done on the lock
-				 * when the lib opens the file it is already created
-				 */
-				file_mode = "w+b";
-				lock_file_mode = "a+b";
+				file_mode = "a+b";
 			}
+			/* In case of the 'a+b' append mode, the handler is responsible 
+			 * to handle any rewind problems (see flatfile handler).
+			 */
 			break;
 		case 'n':
 			modenr = DBA_TRUNC;
diff --git a/ext/dba/dba_flatfile.c b/ext/dba/dba_flatfile.c
index feba2c8da8..fa1232779a 100644
--- a/ext/dba/dba_flatfile.c
+++ b/ext/dba/dba_flatfile.c
@@ -41,6 +41,17 @@
 
 DBA_OPEN_FUNC(flatfile)
 {
+	int fd, flags;
+
+	if (info->mode != DBA_READER) {
+		if (SUCCESS != php_stream_cast(info->fp, PHP_STREAM_AS_FD, (void*)&fd, 1)) {
+			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Could not cast stream");
+			return FAILURE;
+		}
+		flags = fcntl(fd, F_SETFL);
+		fcntl(fd, F_SETFL, flags & ~O_APPEND);
+	}
+
 	info->dbf = pemalloc(sizeof(flatfile), info->flags&DBA_PERSISTENT);
 	memset(info->dbf, 0, sizeof(flatfile));