1 /* $OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. The name of the author may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 21 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 22 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 23 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/types.h> 33 #include <sys/libkern.h> 34 35 /* 36 * Appends src to string dst of size siz (unlike strncat, siz is the 37 * full size of dst, not space left). At most siz-1 characters 38 * will be copied. Always NUL terminates (unless siz <= strlen(dst)). 39 * Returns strlen(src) + MIN(siz, strlen(initial dst)). 40 * If retval >= siz, truncation occurred. 41 */ 42 size_t 43 strlcat(char *dst, const char *src, size_t siz) 44 { 45 char *d = dst; 46 const char *s = src; 47 size_t n = siz; 48 size_t dlen; 49 50 /* Find the end of dst and adjust bytes left but don't go past end */ 51 while (n-- != 0 && *d != '\0') 52 d++; 53 dlen = d - dst; 54 n = siz - dlen; 55 56 if (n == 0) 57 return(dlen + strlen(s)); 58 while (*s != '\0') { 59 if (n != 1) { 60 *d++ = *s; 61 n--; 62 } 63 s++; 64 } 65 *d = '\0'; 66 67 return(dlen + (s - src)); /* count does not include NUL */ 68 } 69