lib/libc/ssp/strncat_chk.c

   1 /*      $NetBSD: strncat_chk.c,v 1.5 2014/09/17 00:39:28 joerg Exp $    */
   2
   3 /*-
   4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Christos Zoulas.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 #include <sys/cdefs.h>
  32 __RCSID("$NetBSD: strncat_chk.c,v 1.5 2014/09/17 00:39:28 joerg Exp $");
  33
  34 /*LINTLIBRARY*/
  35
  36 #include <ssp/ssp.h>
  37 #include <string.h>
  38 #include <stdio.h>
  39
  40 char *__strncat_chk(char * __restrict, const char * __restrict, size_t,
  41     size_t);
  42
  43 char *
  44 __strncat_chk(char * __restrict dst, const char * __restrict src, size_t len,
  45     size_t slen)
  46 {
  47         char *d;
  48
  49         if (len == 0)
  50                 return dst;
  51
  52         if (len > slen)
  53                 __chk_fail();
  54
  55         for (d = dst; *d; d++) {
  56                 if (slen-- == 0)
  57                         __chk_fail();
  58         }
  59
  60         do {
  61                 if ((*d = *src++) == '\0')
  62                         break;
  63                 if (slen-- == 0)
  64                         __chk_fail();
  65                 d++;
  66         } while (--len != 0);
  67
  68         if (slen-- == 0)
  69                 __chk_fail();
  70
  71         *d = '\0';
  72         return dst;
  73 }