common/lib/libc/string/strlcpy.c

   1 /*      $NetBSD: strlcpy.c,v 1.2 2006/03/30 20:37:51 christos Exp $     */
   2 /*      $OpenBSD: strlcpy.c,v 1.7 2003/04/12 21:56:39 millert Exp $     */
   3
   4 /*
   5  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
  12  * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  13  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
  14  * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  16  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  17  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #if !defined(_KERNEL) && !defined(_STANDALONE)
  21 #if HAVE_NBTOOL_CONFIG_H
  22 #include "nbtool_config.h"
  23 #endif
  24
  25 #include <sys/cdefs.h>
  26 #if defined(LIBC_SCCS) && !defined(lint)
  27 __RCSID("$NetBSD: strlcpy.c,v 1.2 2006/03/30 20:37:51 christos Exp $");
  28 #endif /* LIBC_SCCS and not lint */
  29
  30 #ifdef _LIBC
  31 #include "namespace.h"
  32 #endif
  33 #include <sys/types.h>
  34 #include <assert.h>
  35 #include <string.h>
  36
  37 #ifdef _LIBC
  38 # ifdef __weak_alias
  39 __weak_alias(strlcpy, _strlcpy)
  40 # endif
  41 #endif
  42 #else
  43 #include <lib/libkern/libkern.h>
  44 #endif /* !_KERNEL && !_STANDALONE */
  45
  46
  47 #if !HAVE_STRLCPY
  48 /*
  49  * Copy src to string dst of size siz.  At most siz-1 characters
  50  * will be copied.  Always NUL terminates (unless siz == 0).
  51  * Returns strlen(src); if retval >= siz, truncation occurred.
  52  */
  53 size_t
  54 strlcpy(char *dst, const char *src, size_t siz)
  55 {
  56         char *d = dst;
  57         const char *s = src;
  58         size_t n = siz;
  59
  60         _DIAGASSERT(dst != NULL);
  61         _DIAGASSERT(src != NULL);
  62
  63         /* Copy as many bytes as will fit */
  64         if (n != 0 && --n != 0) {
  65                 do {
  66                         if ((*d++ = *s++) == 0)
  67                                 break;
  68                 } while (--n != 0);
  69         }
  70
  71         /* Not enough room in dst, add NUL and traverse rest of src */
  72         if (n == 0) {
  73                 if (siz != 0)
  74                         *d = '\0';              /* NUL-terminate dst */
  75                 while (*s++)
  76                         ;
  77         }
  78
  79         return(s - src - 1);    /* count does not include NUL */
  80 }
  81 #endif