xref: /freebsd/lib/libc/string/strlcpy.c (revision b1f9167f94059fd55c630891d359bcff987bd7eb)
1 /*	$OpenBSD: strlcpy.c,v 1.11 2006/05/05 15:27:38 millert Exp $	*/
2 
3 /*
4  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/cdefs.h>
20 __FBSDID("$FreeBSD$");
21 
22 #include <sys/types.h>
23 #include <string.h>
24 
25 /*
26  * Copy src to string dst of size siz.  At most siz-1 characters
27  * will be copied.  Always NUL terminates (unless siz == 0).
28  * Returns strlen(src); if retval >= siz, truncation occurred.
29  */
30 size_t
31 strlcpy(char * __restrict dst, const char * __restrict src, size_t siz)
32 {
33 	char *d = dst;
34 	const char *s = src;
35 	size_t n = siz;
36 
37 	/* Copy as many bytes as will fit */
38 	if (n != 0) {
39 		while (--n != 0) {
40 			if ((*d++ = *s++) == '\0')
41 				break;
42 		}
43 	}
44 
45 	/* Not enough room in dst, add NUL and traverse rest of src */
46 	if (n == 0) {
47 		if (siz != 0)
48 			*d = '\0';		/* NUL-terminate dst */
49 		while (*s++)
50 			;
51 	}
52 
53 	return(s - src - 1);	/* count does not include NUL */
54 }
55