xref: /dragonfly/sys/libkern/strlcpy.c (revision f9a239ec)
1 /*
2  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
17  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
18  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
19  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  *
27  * $OpenBSD: strlcpy.c,v 1.4 1999/05/01 18:56:41 millert Exp $
28  * $FreeBSD: src/lib/libc/string/strlcpy.c,v 1.2.4.1 2001/07/09 23:30:06 obrien Exp $
29  * $DragonFly: src/sys/libkern/strlcpy.c,v 1.3 2004/12/19 11:56:45 liamfoy Exp $
30  */
31 
32 #include <sys/types.h>
33 #include <string.h>
34 
35 /*
36  * Copy src to string dst of size siz.  At most siz-1 characters
37  * will be copied.  Always NUL terminates (unless siz == 0).
38  * Returns strlen(src); if retval >= siz, truncation occurred.
39  */
40 size_t
41 strlcpy(char *dst, const char *src, size_t siz)
42 {
43 	char *d = dst;
44 	const char *s = src;
45 	size_t n = siz;
46 
47 	/* Copy as many bytes as will fit */
48 	if (n != 0 && --n != 0) {
49 		do {
50 			if ((*d++ = *s++) == 0)
51 				break;
52 		} while (--n != 0);
53 	}
54 
55 	/* Not enough room in dst, add NUL and traverse rest of src */
56 	if (n == 0) {
57 		if (siz != 0)
58 			*d = '\0';		/* NUL-terminate dst */
59 		while (*s++)
60 			;
61 	}
62 
63 	return(s - src - 1);	/* count does not include NUL */
64 }
65