xref: /freebsd/crypto/openssh/openbsd-compat/strlcat.c (revision a35d88931c87cfe6bd38f01d7bad22140b3b38f3)
1 /* OPENBSD ORIGINAL: lib/libc/string/strlcat.c */
2 
3 /*	$OpenBSD: strlcat.c,v 1.11 2003/06/17 21:56:24 millert Exp $	*/
4 
5 /*
6  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
7  *
8  * Permission to use, copy, modify, and distribute this software for any
9  * purpose with or without fee is hereby granted, provided that the above
10  * copyright notice and this permission notice appear in all copies.
11  *
12  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
15  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
18  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19  */
20 
21 #include "includes.h"
22 #ifndef HAVE_STRLCAT
23 
24 #if defined(LIBC_SCCS) && !defined(lint)
25 static char *rcsid = "$OpenBSD: strlcat.c,v 1.11 2003/06/17 21:56:24 millert Exp $";
26 #endif /* LIBC_SCCS and not lint */
27 
28 #include <sys/types.h>
29 #include <string.h>
30 
31 /*
32  * Appends src to string dst of size siz (unlike strncat, siz is the
33  * full size of dst, not space left).  At most siz-1 characters
34  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
35  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
36  * If retval >= siz, truncation occurred.
37  */
38 size_t
39 strlcat(char *dst, const char *src, size_t siz)
40 {
41 	register char *d = dst;
42 	register const char *s = src;
43 	register size_t n = siz;
44 	size_t dlen;
45 
46 	/* Find the end of dst and adjust bytes left but don't go past end */
47 	while (n-- != 0 && *d != '\0')
48 		d++;
49 	dlen = d - dst;
50 	n = siz - dlen;
51 
52 	if (n == 0)
53 		return(dlen + strlen(s));
54 	while (*s != '\0') {
55 		if (n != 1) {
56 			*d++ = *s;
57 			n--;
58 		}
59 		s++;
60 	}
61 	*d = '\0';
62 
63 	return(dlen + (s - src));	/* count does not include NUL */
64 }
65 
66 #endif /* !HAVE_STRLCAT */
67