xref: /freebsd/contrib/unbound/compat/strlcat.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
1 /* compat/strlcat.c */
2 
3 /*-
4  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
21  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 /* OPENBSD ORIGINAL: lib/libc/string/strlcat.c */
31 
32 #include "config.h"
33 #ifndef HAVE_STRLCAT
34 
35 #include <sys/types.h>
36 #include <string.h>
37 
38 /*
39  * Appends src to string dst of size siz (unlike strncat, siz is the
40  * full size of dst, not space left).  At most siz-1 characters
41  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
42  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
43  * If retval >= siz, truncation occurred.
44  */
45 size_t
46 strlcat(char *dst, const char *src, size_t siz)
47 {
48 	char *d = dst;
49 	const char *s = src;
50 	size_t n = siz;
51 	size_t dlen;
52 
53 	/* Find the end of dst and adjust bytes left but don't go past end */
54 	while (n-- != 0 && *d != '\0')
55 		d++;
56 	dlen = d - dst;
57 	n = siz - dlen;
58 
59 	if (n == 0)
60 		return(dlen + strlen(s));
61 	while (*s != '\0') {
62 		if (n != 1) {
63 			*d++ = *s;
64 			n--;
65 		}
66 		s++;
67 	}
68 	*d = '\0';
69 
70 	return(dlen + (s - src));	/* count does not include NUL */
71 }
72 
73 #endif /* !HAVE_STRLCAT */
74