1 /* $OpenBSD: strlcpy.c,v 1.12 2015/01/15 03:54:12 millert Exp $ */ 2 3 /* 4 * Copyright (c) 1998, 2015 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 #include <sys/cdefs.h> 20 __FBSDID("$FreeBSD$"); 21 22 #include <sys/types.h> 23 #include <sys/libkern.h> 24 25 /* 26 * Copy string src to buffer dst of size dsize. At most dsize-1 27 * chars will be copied. Always NUL terminates (unless dsize == 0). 28 * Returns strlen(src); if retval >= dsize, truncation occurred. 29 */ 30 size_t 31 strlcpy(char * __restrict dst, const char * __restrict src, size_t dsize) 32 { 33 const char *osrc = src; 34 size_t nleft = dsize; 35 36 /* Copy as many bytes as will fit. */ 37 if (nleft != 0) { 38 while (--nleft != 0) { 39 if ((*dst++ = *src++) == '\0') 40 break; 41 } 42 } 43 44 /* Not enough room in dst, add NUL and traverse rest of src. */ 45 if (nleft == 0) { 46 if (dsize != 0) 47 *dst = '\0'; /* NUL-terminate dst */ 48 while (*src++) 49 ; 50 } 51 52 return(src - osrc - 1); /* count does not include NUL */ 53 } 54