1 /* $NetBSD: strlcat.c,v 1.4 2013/01/23 07:57:27 matt Exp $ */
2 /* $OpenBSD: strlcat.c,v 1.10 2003/04/12 21:56:39 millert Exp $ */
3
4 /*
5 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
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 TODD C. MILLER DISCLAIMS ALL
12 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
13 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
14 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
16 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
17 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #include "config.h"
21
22 #if defined(LIBC_SCCS) && !defined(lint)
23 __RCSID("$NetBSD: strlcat.c,v 1.4 2013/01/23 07:57:27 matt Exp $");
24 #endif /* LIBC_SCCS and not lint */
25
26 #include <sys/types.h>
27 #include <assert.h>
28 #include <string.h>
29
30 #ifdef _LIBC
31 # ifdef __weak_alias
__weak_alias(strlcat,_strlcat)32 __weak_alias(strlcat, _strlcat)
33 # endif
34 #endif
35
36 #if !HAVE_STRLCAT
37 /*
38 * Appends src to string dst of size siz (unlike strncat, siz is the
39 * full size of dst, not space left). At most siz-1 characters
40 * will be copied. Always NUL terminates (unless siz <= strlen(dst)).
41 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
42 * If retval >= siz, truncation occurred.
43 */
44 size_t
45 strlcat(char *dst, const char *src, size_t siz)
46 {
47 #if 1
48 char *d = dst;
49 const char *s = src;
50 size_t n = siz;
51 size_t dlen;
52
53 _DIAGASSERT(dst != NULL);
54 _DIAGASSERT(src != NULL);
55
56 /* Find the end of dst and adjust bytes left but don't go past end */
57 while (n-- != 0 && *d != '\0')
58 d++;
59 dlen = d - dst;
60 n = siz - dlen;
61
62 if (n == 0)
63 return(dlen + strlen(s));
64 while (*s != '\0') {
65 if (n != 1) {
66 *d++ = *s;
67 n--;
68 }
69 s++;
70 }
71 *d = '\0';
72
73 return(dlen + (s - src)); /* count does not include NUL */
74 #else
75 _DIAGASSERT(dst != NULL);
76 _DIAGASSERT(src != NULL);
77
78 /*
79 * Find length of string in dst (maxing out at siz).
80 */
81 size_t dlen = strnlen(dst, siz);
82
83 /*
84 * Copy src into any remaining space in dst (truncating if needed).
85 * Note strlcpy(dst, src, 0) returns strlen(src).
86 */
87 return dlen + strlcpy(dst + dlen, src, siz - dlen);
88 #endif
89 }
90 #endif
91