1/*	$NetBSD: strncat_chk.c,v 1.3 2008/04/28 20:23:00 martin Exp $	*/
2
3/*-
4 * Copyright (c) 2006 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31#include <sys/cdefs.h>
32__RCSID("$NetBSD: strncat_chk.c,v 1.3 2008/04/28 20:23:00 martin Exp $");
33
34/*LINTLIBRARY*/
35
36#include <ssp/ssp.h>
37#include <string.h>
38#include <stdio.h>
39
40char *
41__strncat_chk(char * __restrict dst, const char * __restrict src, size_t len,
42    size_t slen)
43{
44	char *d;
45
46	if (len == 0)
47		return dst;
48
49	if (len > slen)
50		__chk_fail();
51
52	for (d = dst; *d; d++) {
53		if (slen-- == 0)
54			__chk_fail();
55	}
56
57	do {
58		if ((*d = *src++) == '\0')
59			break;
60		if (slen-- == 0)
61			__chk_fail();
62		d++;
63	} while (--len != 0);
64
65	if (slen-- == 0)
66		__chk_fail();
67
68	*d = '\0';
69	return dst;
70}
71