diff --git a/xwayland/launcher.c b/xwayland/launcher.c
index dcc4b972..97d7c6ee 100644
--- a/xwayland/launcher.c
+++ b/xwayland/launcher.c
@@ -166,6 +166,9 @@ create_lockfile(int display, char *lockfile, size_t lsize)
 			return -1;
 		}
 
+		/* Trim the newline, ensure terminated string. */
+		pid[10] = '\0';
+
 		if (!safe_strtoint(pid, &other)) {
 			weston_log("can't parse lock file %s\n",
 				lockfile);