1/* $NetBSD: strlcat.c,v 1.5 2024/11/01 21:11:37 riastradh 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#if !defined(_KERNEL) && !defined(_STANDALONE)
21#if HAVE_NBTOOL_CONFIG_H
22#include "nbtool_config.h"
23#endif
24
25#include <sys/cdefs.h>
26#if defined(LIBC_SCCS) && !defined(lint)
27__RCSID("$NetBSD: strlcat.c,v 1.5 2024/11/01 21:11:37 riastradh Exp $");
28#endif /* LIBC_SCCS and not lint */
29
30#ifdef _LIBC
31#include "namespace.h"
32#endif
33#include <sys/types.h>
34#include <assert.h>
35#include <string.h>
36
37#ifdef _LIBC
38# ifdef __weak_alias
39__weak_alias(strlcat, _strlcat)
40# endif
41#endif
42
43#else
44#include <lib/libkern/libkern.h>
45#endif /* !_KERNEL && !_STANDALONE */
46
47#if !HAVE_STRLCAT
48/*
49 * Appends src to string dst of size siz (unlike strncat, siz is the
50 * full size of dst, not space left). At most siz-1 characters
51 * will be copied. Always NUL terminates (unless siz <= strlen(dst)).
52 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
53 * If retval >= siz, truncation occurred.
54 */
55size_t
56strlcat(char *__restrict dst, const char *__restrict src, size_t siz)
57{
58#if 1
59 char *d = dst;
60 const char *s = src;
61 size_t n = siz;
62 size_t dlen;
63
64 _DIAGASSERT(dst != NULL);
65 _DIAGASSERT(src != NULL);
66
67 /* Find the end of dst and adjust bytes left but don't go past end */
68 while (n-- != 0 && *d != '\0')
69 d++;
70 dlen = d - dst;
71 n = siz - dlen;
72
73 if (n == 0)
74 return(dlen + strlen(s));
75 while (*s != '\0') {
76 if (n != 1) {
77 *d++ = *s;
78 n--;
79 }
80 s++;
81 }
82 *d = '\0';
83
84 return(dlen + (s - src)); /* count does not include NUL */
85#else
86 _DIAGASSERT(dst != NULL);
87 _DIAGASSERT(src != NULL);
88
89 /*
90 * Find length of string in dst (maxing out at siz).
91 */
92 size_t dlen = strnlen(dst, siz);
93
94 /*
95 * Copy src into any remaining space in dst (truncating if needed).
96 * Note strlcpy(dst, src, 0) returns strlen(src).
97 */
98 return dlen + strlcpy(dst + dlen, src, siz - dlen);
99#endif
100}
101#endif
