1 /* $OpenBSD: strlcat.c,v 1.5 2004/08/07 00:38:33 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #if defined(LIBC_SCCS) && !defined(lint) 20 static char *rcsid = "$OpenBSD: strlcat.c,v 1.5 2004/08/07 00:38:33 deraadt Exp $"; 21 #endif /* LIBC_SCCS and not lint */ 22 23 #if !defined(_KERNEL) && !defined(_STANDALONE) 24 #include <sys/types.h> 25 #include <string.h> 26 #else 27 #include <lib/libkern/libkern.h> 28 #endif 29 30 /* 31 * Appends src to string dst of size siz (unlike strncat, siz is the 32 * full size of dst, not space left). At most siz-1 characters 33 * will be copied. Always NUL terminates (unless siz <= strlen(dst)). 34 * Returns strlen(src) + MIN(siz, strlen(initial dst)). 35 * If retval >= siz, truncation occurred. 36 */ 37 size_t 38 strlcat(char *dst, const char *src, size_t siz) 39 { 40 char *d = dst; 41 const char *s = src; 42 size_t n = siz; 43 size_t dlen; 44 45 /* Find the end of dst and adjust bytes left but don't go past end */ 46 while (n-- != 0 && *d != '\0') 47 d++; 48 dlen = d - dst; 49 n = siz - dlen; 50 51 if (n == 0) 52 return(dlen + strlen(s)); 53 while (*s != '\0') { 54 if (n != 1) { 55 *d++ = *s; 56 n--; 57 } 58 s++; 59 } 60 *d = '\0'; 61 62 return(dlen + (s - src)); /* count does not include NUL */ 63 } 64