Check whether stderr is a tty before trying TIOCGWINSZ.

sudo-project · Apr 16, 2023 · 5650b43 · 5650b43
1 parent ae12d18
commit 5650b43
Showing 1 changed file with 6 additions and 5 deletions.
diff --git a/lib/util/ttysize.c b/lib/util/ttysize.c
@@ -39,11 +39,12 @@ get_ttysize_ioctl(int *rowp, int *colp)
     struct winsize wsize;
     debug_decl(get_ttysize_ioctl, SUDO_DEBUG_UTIL);
 
-    if (ioctl(STDERR_FILENO, TIOCGWINSZ, &wsize) == 0 &&
-	wsize.ws_row != 0 && wsize.ws_col  != 0) {
-	*rowp = wsize.ws_row;
-	*colp = wsize.ws_col;
-	debug_return_int(0);
+    if (isatty(STDERR_FILENO) && ioctl(STDERR_FILENO, TIOCGWINSZ, &wsize) == 0) {
+	if (wsize.ws_row != 0 && wsize.ws_col != 0) {
+	    *rowp = wsize.ws_row;
+	    *colp = wsize.ws_col;
+	    debug_return_int(0);
+	}
     }
     debug_return_int(-1);
 }