1 6303eedc 2020-10-24 stsp /*	$OpenBSD: strlcat.c,v 1.19 2019/01/25 00:19:25 millert Exp $	*/
 2 6303eedc 2020-10-24 stsp 
 3 6303eedc 2020-10-24 stsp /*
 4 6303eedc 2020-10-24 stsp  * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
 5 6303eedc 2020-10-24 stsp  *
 6 6303eedc 2020-10-24 stsp  * Permission to use, copy, modify, and distribute this software for any
 7 6303eedc 2020-10-24 stsp  * purpose with or without fee is hereby granted, provided that the above
 8 6303eedc 2020-10-24 stsp  * copyright notice and this permission notice appear in all copies.
 9 6303eedc 2020-10-24 stsp  *
10 6303eedc 2020-10-24 stsp  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 6303eedc 2020-10-24 stsp  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 6303eedc 2020-10-24 stsp  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 6303eedc 2020-10-24 stsp  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 6303eedc 2020-10-24 stsp  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 6303eedc 2020-10-24 stsp  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 6303eedc 2020-10-24 stsp  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 6303eedc 2020-10-24 stsp  */
18 6303eedc 2020-10-24 stsp 
19 6303eedc 2020-10-24 stsp #include <sys/types.h>
20 6303eedc 2020-10-24 stsp #include <string.h>
21 6303eedc 2020-10-24 stsp 
22 6303eedc 2020-10-24 stsp /*
23 6303eedc 2020-10-24 stsp  * Appends src to string dst of size dsize (unlike strncat, dsize is the
24 6303eedc 2020-10-24 stsp  * full size of dst, not space left).  At most dsize-1 characters
25 6303eedc 2020-10-24 stsp  * will be copied.  Always NUL terminates (unless dsize <= strlen(dst)).
26 6303eedc 2020-10-24 stsp  * Returns strlen(src) + MIN(dsize, strlen(initial dst)).
27 6303eedc 2020-10-24 stsp  * If retval >= dsize, truncation occurred.
28 6303eedc 2020-10-24 stsp  */
29 6303eedc 2020-10-24 stsp size_t
30 6303eedc 2020-10-24 stsp strlcat(char *dst, const char *src, size_t dsize)
31 6303eedc 2020-10-24 stsp {
32 6303eedc 2020-10-24 stsp 	const char *odst = dst;
33 6303eedc 2020-10-24 stsp 	const char *osrc = src;
34 6303eedc 2020-10-24 stsp 	size_t n = dsize;
35 6303eedc 2020-10-24 stsp 	size_t dlen;
36 6303eedc 2020-10-24 stsp 
37 6303eedc 2020-10-24 stsp 	/* Find the end of dst and adjust bytes left but don't go past end. */
38 6303eedc 2020-10-24 stsp 	while (n-- != 0 && *dst != '\0')
39 6303eedc 2020-10-24 stsp 		dst++;
40 6303eedc 2020-10-24 stsp 	dlen = dst - odst;
41 6303eedc 2020-10-24 stsp 	n = dsize - dlen;
42 6303eedc 2020-10-24 stsp 
43 6303eedc 2020-10-24 stsp 	if (n-- == 0)
44 6303eedc 2020-10-24 stsp 		return(dlen + strlen(src));
45 6303eedc 2020-10-24 stsp 	while (*src != '\0') {
46 6303eedc 2020-10-24 stsp 		if (n != 0) {
47 6303eedc 2020-10-24 stsp 			*dst++ = *src;
48 6303eedc 2020-10-24 stsp 			n--;
49 6303eedc 2020-10-24 stsp 		}
50 6303eedc 2020-10-24 stsp 		src++;
51 6303eedc 2020-10-24 stsp 	}
52 6303eedc 2020-10-24 stsp 	*dst = '\0';
53 6303eedc 2020-10-24 stsp 
54 6303eedc 2020-10-24 stsp 	return(dlen + (src - osrc));	/* count does not include NUL */
55 6303eedc 2020-10-24 stsp }