lib/libc/ssp/gets_chk.c

   1 /*      $NetBSD: gets_chk.c,v 1.6 2010/01/17 23:13:32 wiz 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: gets_chk.c,v 1.6 2010/01/17 23:13:32 wiz Exp $");
  33
  34 /*LINTLIBRARY*/
  35
  36 #include <ssp/ssp.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include <limits.h>
  40 #include <stdlib.h>
  41 #include <ssp/stdio.h>
  42
  43 #undef gets
  44
  45 char *
  46 __gets_chk(char * __restrict buf, size_t slen)
  47 {
  48         char *abuf;
  49         size_t len;
  50
  51         if (slen >= (size_t)INT_MAX)
  52                 return gets(buf);
  53
  54         if ((abuf = malloc(slen + 1)) == NULL)
  55                 return gets(buf);
  56
  57         if (fgets(abuf, (int)(slen + 1), stdin) == NULL) {
  58                 free(abuf);
  59                 return NULL;
  60         }
  61
  62         len = strlen(abuf);
  63         if (len > 0 && abuf[len - 1] == '\n')
  64                 --len;
  65
  66         if (len >= slen)
  67                 __chk_fail();
  68
  69         (void)memcpy(buf, abuf, len);
  70
  71         buf[len] = '\0';
  72         free(abuf);
  73         return buf;
  74 }