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gets_chk.c revision 1.4 
      1 /*	$NetBSD: gets_chk.c,v 1.4 2007/08/04 19:37:52 kristerw 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  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 #include <sys/cdefs.h>
     39 __RCSID("$NetBSD: gets_chk.c,v 1.4 2007/08/04 19:37:52 kristerw Exp $");
     40 
     41 /*LINTLIBRARY*/
     42 
     43 #include <ssp/ssp.h>
     44 #include <stdio.h>
     45 #include <string.h>
     46 #include <limits.h>
     47 #include <stdlib.h>
     48 #include <ssp/stdio.h>
     49 
     50 #undef gets
     51 
     52 char *
     53 __gets_chk(char * __restrict buf, size_t slen)
     54 {
     55 	char *abuf;
     56 	size_t len;
     57 
     58 	if (slen >= (size_t)INT_MAX)
     59 		return gets(buf);
     60 
     61 	if ((abuf = malloc(slen + 1)) == NULL)
     62 		return gets(buf);
     63 
     64 	if (fgets(abuf, (int)(slen + 1), stdin) == NULL)
     65 		return NULL;
     66 
     67 	len = strlen(abuf);
     68 	if (len > 0 && abuf[len - 1] == '\n')
     69 		--len;
     70 
     71 	if (len >= slen)
     72 		__chk_fail();
     73 
     74 	(void)memcpy(buf, abuf, len);
     75 
     76 	buf[len] = '\0';
     77 	free(abuf);
     78 	return buf;
     79 }
     80