1/*	$OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. The name of the author may not be used to endorse or promote products
18 *    derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
21 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
22 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
23 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/types.h>
33#include <sys/libkern.h>
34
35/*
36 * Appends src to string dst of size siz (unlike strncat, siz is the
37 * full size of dst, not space left).  At most siz-1 characters
38 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
39 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
40 * If retval >= siz, truncation occurred.
41 */
42size_t
43strlcat(char *dst, const char *src, size_t siz)
44{
45	char *d = dst;
46	const char *s = src;
47	size_t n = siz;
48	size_t dlen;
49
50	/* Find the end of dst and adjust bytes left but don't go past end */
51	while (n-- != 0 && *d != '\0')
52		d++;
53	dlen = d - dst;
54	n = siz - dlen;
55
56	if (n == 0)
57		return(dlen + strlen(s));
58	while (*s != '\0') {
59		if (n != 1) {
60			*d++ = *s;
61			n--;
62		}
63		s++;
64	}
65	*d = '\0';
66
67	return(dlen + (s - src));	/* count does not include NUL */
68}
69