xref: /dragonfly/lib/libc/string/strlcpy.c (revision 36a3d1d6)
1 /*
2  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  *
16  * $OpenBSD: strlcpy.c,v 1.11 2006/05/05 15:27:38 millert Exp $
17  * $FreeBSD: src/lib/libc/string/strlcpy.c,v 1.10 2008/10/19 10:11:35 delphij Exp $
18  * $DragonFly: src/lib/libc/string/strlcpy.c,v 1.4 2005/09/18 16:32:34 asmodai Exp $
19  */
20 
21 #include <sys/types.h>
22 #include <string.h>
23 
24 /*
25  * Copy src to string dst of size siz.  At most siz-1 characters
26  * will be copied.  Always NUL terminates (unless siz == 0).
27  * Returns strlen(src); if retval >= siz, truncation occurred.
28  */
29 size_t
30 strlcpy(char *dst, const char *src, size_t siz)
31 {
32 	char *d = dst;
33 	const char *s = src;
34 	size_t n = siz;
35 
36 	/* Copy as many bytes as will fit */
37 	if (n != 0) {
38 		while (--n != 0) {
39 			if ((*d++ = *s++) == '\0')
40 				break;
41 		}
42 	}
43 
44 	/* Not enough room in dst, add NUL and traverse rest of src */
45 	if (n == 0) {
46 		if (siz != 0)
47 			*d = '\0';		/* NUL-terminate dst */
48 		while (*s++)
49 			;
50 	}
51 
52 	return(s - src - 1);	/* count does not include NUL */
53 }
54