lib/libc/string/strlcpy.c

   1 /*
   2  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  *
  16  * $OpenBSD: strlcpy.c,v 1.11 2006/05/05 15:27:38 millert Exp $
  17  * $FreeBSD: src/lib/libc/string/strlcpy.c,v 1.10 2008/10/19 10:11:35 delphij Exp $
  18  * $DragonFly: src/lib/libc/string/strlcpy.c,v 1.4 2005/09/18 16:32:34 asmodai Exp $
  19  */
  20
  21 #include <sys/types.h>
  22 #include <string.h>
  23
  24 /*
  25  * Copy src to string dst of size siz.  At most siz-1 characters
  26  * will be copied.  Always NUL terminates (unless siz == 0).
  27  * Returns strlen(src); if retval >= siz, truncation occurred.
  28  */
  29 size_t
  30 strlcpy(char *dst, const char *src, size_t siz)
  31 {
  32         char *d = dst;
  33         const char *s = src;
  34         size_t n = siz;
  35
  36         /* Copy as many bytes as will fit */
  37         if (n != 0) {
  38                 while (--n != 0) {
  39                         if ((*d++ = *s++) == '\0')
  40                                 break;
  41                 }
  42         }
  43
  44         /* Not enough room in dst, add NUL and traverse rest of src */
  45         if (n == 0) {
  46                 if (siz != 0)
  47                         *d = '\0';              /* NUL-terminate dst */
  48                 while (*s++)
  49                         ;
  50         }
  51
  52         return(s - src - 1);    /* count does not include NUL */
  53 }