xref: /dragonfly/lib/libc/string/strlcpy.c (revision 611395e5)
1 /*	$OpenBSD: strlcpy.c,v 1.4 1999/05/01 18:56:41 millert Exp $	*/
2 
3 /*
4  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
21  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  *
29  * $OpenBSD: strlcpy.c,v 1.4 1999/05/01 18:56:41 millert Exp $
30  * $FreeBSD: src/lib/libc/string/strlcpy.c,v 1.2.4.1 2001/07/09 23:30:06 obrien Exp $
31  * $DragonFly: src/lib/libc/string/strlcpy.c,v 1.3 2004/10/25 19:38:02 drhodus Exp $
32  */
33 
34 #include <sys/types.h>
35 #include <string.h>
36 
37 /*
38  * Copy src to string dst of size siz.  At most siz-1 characters
39  * will be copied.  Always NUL terminates (unless siz == 0).
40  * Returns strlen(src); if retval >= siz, truncation occurred.
41  */
42 size_t strlcpy(dst, src, siz)
43 	char *dst;
44 	const char *src;
45 	size_t siz;
46 {
47 	char *d = dst;
48 	const char *s = src;
49 	size_t n = siz;
50 
51 	/* Copy as many bytes as will fit */
52 	if (n != 0 && --n != 0) {
53 		do {
54 			if ((*d++ = *s++) == 0)
55 				break;
56 		} while (--n != 0);
57 	}
58 
59 	/* Not enough room in dst, add NUL and traverse rest of src */
60 	if (n == 0) {
61 		if (siz != 0)
62 			*d = '\0';		/* NUL-terminate dst */
63 		while (*s++)
64 			;
65 	}
66 
67 	return(s - src - 1);	/* count does not include NUL */
68 }
69