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      1 /*	$OpenBSD: reallocarray.c,v 1.1 2014/05/08 21:43:49 deraadt Exp $	*/
      2 /*
      3  * Copyright (c) 2008 Otto Moerbeek <otto (at) drijf.net>
      4  *
      5  * Permission to use, copy, modify, and distribute this software for any
      6  * purpose with or without fee is hereby granted, provided that the above
      7  * copyright notice and this permission notice appear in all copies.
      8  *
      9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     16  */
     17 
     18 #include "config.h"
     19 #include <sys/types.h>
     20 #include <errno.h>
     21 #ifdef HAVE_STDINT_H
     22 #include <stdint.h>
     23 #endif
     24 #include <limits.h>
     25 #include <stdlib.h>
     26 
     27 /*
     28  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
     29  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
     30  */
     31 #define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))
     32 
     33 void *
     34 reallocarray(void *optr, size_t nmemb, size_t size)
     35 {
     36 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
     37 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
     38 		errno = ENOMEM;
     39 		return NULL;
     40 	}
     41 	return realloc(optr, size * nmemb);
     42 }
     43