1  /*	$NetBSD: strlcat.c,v 1.3 2007/06/04 18:19:27 christos Exp $	*/
 2  /*	$OpenBSD: strlcat.c,v 1.10 2003/04/12 21:56:39 millert Exp $	*/
 3  
 4  /*
 5   * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
 6   *
 7   * Permission to use, copy, modify, and distribute this software for any
 8   * purpose with or without fee is hereby granted, provided that the above
 9   * copyright notice and this permission notice appear in all copies.
10   *
11   * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
12   * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
13   * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
14   * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
16   * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
17   * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18   */
19  
20  #include "config.h"
21  
22  #if defined(LIBC_SCCS) && !defined(lint)
23  __RCSID("$NetBSD: strlcat.c,v 1.3 2007/06/04 18:19:27 christos Exp $");
24  #endif /* LIBC_SCCS and not lint */
25  
26  #include <sys/types.h>
27  #include <assert.h>
28  #include <string.h>
29  
30  #ifdef _LIBC
31  # ifdef __weak_alias
32  __weak_alias(strlcat, _strlcat)
33  # endif
34  #endif
35  
36  #if !HAVE_STRLCAT
37  /*
38   * Appends src to string dst of size siz (unlike strncat, siz is the
39   * full size of dst, not space left).  At most siz-1 characters
40   * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
41   * Returns strlen(src) + MIN(siz, strlen(initial dst)).
42   * If retval >= siz, truncation occurred.
43   */
44  size_t
45  strlcat(char *dst, const char *src, size_t siz)
46  {
47  	char *d = dst;
48  	const char *s = src;
49  	size_t n = siz;
50  	size_t dlen;
51  
52  	_DIAGASSERT(dst != NULL);
53  	_DIAGASSERT(src != NULL);
54  
55  	/* Find the end of dst and adjust bytes left but don't go past end */
56  	while (n-- != 0 && *d != '\0')
57  		d++;
58  	dlen = d - dst;
59  	n = siz - dlen;
60  
61  	if (n == 0)
62  		return(dlen + strlen(s));
63  	while (*s != '\0') {
64  		if (n != 1) {
65  			*d++ = *s;
66  			n--;
67  		}
68  		s++;
69  	}
70  	*d = '\0';
71  
72  	return(dlen + (s - src));	/* count does not include NUL */
73  }
74  #endif