1 c423c56e 2022-09-25 op /*
 2 c423c56e 2022-09-25 op  * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
 3 c423c56e 2022-09-25 op  *
 4 c423c56e 2022-09-25 op  * Permission to use, copy, modify, and distribute this software for any
 5 c423c56e 2022-09-25 op  * purpose with or without fee is hereby granted, provided that the above
 6 c423c56e 2022-09-25 op  * copyright notice and this permission notice appear in all copies.
 7 c423c56e 2022-09-25 op  *
 8 c423c56e 2022-09-25 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 9 c423c56e 2022-09-25 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 c423c56e 2022-09-25 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 c423c56e 2022-09-25 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 c423c56e 2022-09-25 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 c423c56e 2022-09-25 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 c423c56e 2022-09-25 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 c423c56e 2022-09-25 op  */
16 c423c56e 2022-09-25 op 
17 c423c56e 2022-09-25 op #include <sys/types.h>
18 c423c56e 2022-09-25 op #include <string.h>
19 c423c56e 2022-09-25 op 
20 c423c56e 2022-09-25 op /*
21 c423c56e 2022-09-25 op  * Appends src to string dst of size dsize (unlike strncat, dsize is the
22 c423c56e 2022-09-25 op  * full size of dst, not space left).  At most dsize-1 characters
23 c423c56e 2022-09-25 op  * will be copied.  Always NUL terminates (unless dsize <= strlen(dst)).
24 c423c56e 2022-09-25 op  * Returns strlen(src) + MIN(dsize, strlen(initial dst)).
25 c423c56e 2022-09-25 op  * If retval >= dsize, truncation occurred.
26 c423c56e 2022-09-25 op  */
27 c423c56e 2022-09-25 op size_t
28 c423c56e 2022-09-25 op strlcat(char *dst, const char *src, size_t dsize)
29 c423c56e 2022-09-25 op {
30 c423c56e 2022-09-25 op 	const char *odst = dst;
31 c423c56e 2022-09-25 op 	const char *osrc = src;
32 c423c56e 2022-09-25 op 	size_t n = dsize;
33 c423c56e 2022-09-25 op 	size_t dlen;
34 c423c56e 2022-09-25 op 
35 c423c56e 2022-09-25 op 	/* Find the end of dst and adjust bytes left but don't go past end. */
36 c423c56e 2022-09-25 op 	while (n-- != 0 && *dst != '\0')
37 c423c56e 2022-09-25 op 		dst++;
38 c423c56e 2022-09-25 op 	dlen = dst - odst;
39 c423c56e 2022-09-25 op 	n = dsize - dlen;
40 c423c56e 2022-09-25 op 
41 c423c56e 2022-09-25 op 	if (n-- == 0)
42 c423c56e 2022-09-25 op 		return(dlen + strlen(src));
43 c423c56e 2022-09-25 op 	while (*src != '\0') {
44 c423c56e 2022-09-25 op 		if (n != 0) {
45 c423c56e 2022-09-25 op 			*dst++ = *src;
46 c423c56e 2022-09-25 op 			n--;
47 c423c56e 2022-09-25 op 		}
48 c423c56e 2022-09-25 op 		src++;
49 c423c56e 2022-09-25 op 	}
50 c423c56e 2022-09-25 op 	*dst = '\0';
51 c423c56e 2022-09-25 op 
52 c423c56e 2022-09-25 op 	return(dlen + (src - osrc));	/* count does not include NUL */
53 c423c56e 2022-09-25 op }