strlcpy.c (1593B)
1 /* $OpenBSD: strlcpy.c,v 1.16 2019/01/25 00:19:25 millert Exp $ */ 2 3 /* 4 * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org> 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/types.h> 20 #include <string.h> 21 22 /* 23 * Copy string src to buffer dst of size dsize. At most dsize-1 24 * chars will be copied. Always NUL terminates (unless dsize == 0). 25 * Returns strlen(src); if retval >= dsize, truncation occurred. 26 */ 27 size_t 28 strlcpy(char *dst, const char *src, size_t dsize) 29 { 30 const char *osrc = src; 31 size_t nleft = dsize; 32 33 /* Copy as many bytes as will fit. */ 34 if (nleft != 0) { 35 while (--nleft != 0) { 36 if ((*dst++ = *src++) == '\0') 37 break; 38 } 39 } 40 41 /* Not enough room in dst, add NUL and traverse rest of src. */ 42 if (nleft == 0) { 43 if (dsize != 0) 44 *dst = '\0'; /* NUL-terminate dst */ 45 while (*src++) 46 ; 47 } 48 49 return(src - osrc - 1); /* count does not include NUL */ 50 }