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 */ 55 size_t 56 strlcat(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 102