xref: /netbsd-src/common/lib/libc/string/strlcat.c (revision d48f14661dda8638fee055ba15d35bdfb29b9fa8)
1 /*	$NetBSD: strlcat.c,v 1.2 2006/03/30 20:37:51 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 #if !defined(_KERNEL) && !defined(_STANDALONE)
21 #if HAVE_NBTOOL_CONFIG_H
22 #include "nbtool_config.h"
23 #endif
24 
25 #include <sys/cdefs.h>
26 #if defined(LIBC_SCCS) && !defined(lint)
27 __RCSID("$NetBSD: strlcat.c,v 1.2 2006/03/30 20:37:51 christos Exp $");
28 #endif /* LIBC_SCCS and not lint */
29 
30 #ifdef _LIBC
31 #include "namespace.h"
32 #endif
33 #include <sys/types.h>
34 #include <assert.h>
35 #include <string.h>
36 
37 #ifdef _LIBC
38 # ifdef __weak_alias
39 __weak_alias(strlcat, _strlcat)
40 # endif
41 #endif
42 
43 #else
44 #include <lib/libkern/libkern.h>
45 #endif /* !_KERNEL && !_STANDALONE */
46 
47 #if !HAVE_STRLCAT
48 /*
49  * Appends src to string dst of size siz (unlike strncat, siz is the
50  * full size of dst, not space left).  At most siz-1 characters
51  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
52  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
53  * If retval >= siz, truncation occurred.
54  */
55 size_t
56 strlcat(dst, src, siz)
57 	char *dst;
58 	const char *src;
59 	size_t siz;
60 {
61 	char *d = dst;
62 	const char *s = src;
63 	size_t n = siz;
64 	size_t dlen;
65 
66 	_DIAGASSERT(dst != NULL);
67 	_DIAGASSERT(src != NULL);
68 
69 	/* Find the end of dst and adjust bytes left but don't go past end */
70 	while (n-- != 0 && *d != '\0')
71 		d++;
72 	dlen = d - dst;
73 	n = siz - dlen;
74 
75 	if (n == 0)
76 		return(dlen + strlen(s));
77 	while (*s != '\0') {
78 		if (n != 1) {
79 			*d++ = *s;
80 			n--;
81 		}
82 		s++;
83 	}
84 	*d = '\0';
85 
86 	return(dlen + (s - src));	/* count does not include NUL */
87 }
88 #endif
89