1 /*	$OpenBSD: strlcpy.c,v 1.16 2019/01/25 00:19:25 millert Exp $	*/
2 
3 /*
4  * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
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/types.h>
20 #include <string.h>
21 
22 #include "compat.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 }