xref: /freebsd/contrib/mandoc/compat_strlcpy.c (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
1 /*	$Id: compat_strlcpy.c,v 1.6 2020/06/15 20:49:57 schwarze Exp $	*/
2 /*	$OpenBSD: strlcpy.c,v 1.16 2019/01/25 00:19:25 millert Exp $	*/
3 
4 /*
5  * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 #include "config.h"
20 
21 #include <sys/types.h>
22 #include <string.h>
23 
24 /*
25  * Copy string src to buffer dst of size dsize.  At most dsize-1
26  * chars will be copied.  Always NUL terminates (unless dsize == 0).
27  * Returns strlen(src); if retval >= dsize, truncation occurred.
28  */
29 size_t
30 strlcpy(char *dst, const char *src, size_t dsize)
31 {
32 	const char *osrc = src;
33 	size_t nleft = dsize;
34 
35 	/* Copy as many bytes as will fit. */
36 	if (nleft != 0) {
37 		while (--nleft != 0) {
38 			if ((*dst++ = *src++) == '\0')
39 				break;
40 		}
41 	}
42 
43 	/* Not enough room in dst, add NUL and traverse rest of src. */
44 	if (nleft == 0) {
45 		if (dsize != 0)
46 			*dst = '\0';		/* NUL-terminate dst */
47 		while (*src++)
48 			;
49 	}
50 
51 	return(src - osrc - 1);	/* count does not include NUL */
52 }
53