RUNTIME_DIR_MODE
if ((sb.st_mode & 0x1FF) != RUNTIME_DIR_MODE) {
session_file = openat(rt_dir_prefix, xdg_session_file, O_CREAT | O_EXCL, RUNTIME_DIR_MODE);
if ((sb.st_mode & 0x1FF) != RUNTIME_DIR_MODE) {
rt_dir = mkdirat(rt_dir_prefix, user, RUNTIME_DIR_MODE);