xref: /freebsd/lib/libc/secure/fgets_chk.c (revision 397e83df75e0fcd0d3fcb95ae4d794cb7600fc89)
1 /*-
2  *
3  * SPDX-License-Identifier: BSD-2-Clause
4  *
5  * Copyright (c) 2006 The NetBSD Foundation, Inc.
6  * All rights reserved.
7  *
8  * This code is derived from software contributed to The NetBSD Foundation
9  * by Christos Zoulas.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: fgets_chk.c,v 1.6 2009/02/05 05:41:51 lukem Exp $");
34 
35 #include <limits.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 
40 #include <ssp/stdio.h>
41 #include <ssp/string.h>
42 #undef fgets
43 
44 char *
45 __fgets_chk(char * __restrict buf, int len, size_t slen, FILE *fp)
46 {
47 	if (slen >= (size_t)INT_MAX)
48 		return (fgets(buf, len, fp));
49 
50 	if (len >= 0 && (size_t)len > slen)
51 		__chk_fail();
52 
53 	return (fgets(buf, len, fp));
54 }
55