From 4eec04afc3730282d2e54e2ec3e899f7d7bc4878 Mon Sep 17 00:00:00 2001
From: espie <espie@openbsd.org>
Date: Mon, 27 Jun 2016 16:52:30 +0000
Subject: [PATCH] make proper use of fstatat, as suggested by guenther@ okay
 millert@

---
 lib/libc/gen/ttyname.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/lib/libc/gen/ttyname.c b/lib/libc/gen/ttyname.c
index 456fe798087..5efbc0d220f 100644
--- a/lib/libc/gen/ttyname.c
+++ b/lib/libc/gen/ttyname.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ttyname.c,v 1.17 2016/06/27 06:10:04 espie Exp $ */
+/*	$OpenBSD: ttyname.c,v 1.18 2016/06/27 16:52:30 espie Exp $ */
 /*
  * Copyright (c) 1988, 1993
  *	The Regents of the University of California.  All rights reserved.
@@ -122,16 +122,14 @@ oldttyname(struct stat *sb, char *buf, size_t len)
 	while ((dirp = readdir(dp))) {
 		if (dirp->d_type != DT_CHR && dirp->d_type != DT_UNKNOWN)
 			continue;
-		if (dirp->d_namlen > len - sizeof(_PATH_DEV)) {
-			(void)closedir(dp);
+		if (fstatat(dirfd(dp), dirp->d_name, &dsb, AT_SYMLINK_NOFOLLOW) 
+		    || !S_ISCHR(dsb.st_mode) || sb->st_rdev != dsb.st_rdev)
+			continue;
+		(void)closedir(dp);
+		if (dirp->d_namlen > len - sizeof(_PATH_DEV))
 			return (ERANGE);
-		}
 		memcpy(buf + sizeof(_PATH_DEV) - 1, dirp->d_name,
 		    dirp->d_namlen + 1);
-		if (lstat(buf, &dsb) || !S_ISCHR(dsb.st_mode) ||
-		    sb->st_rdev != dsb.st_rdev)
-			continue;
-		(void)closedir(dp);
 		return (0);
 	}
 	(void)closedir(dp);
-- 
2.20.1