1/*	$OpenBSD: reallocarray.c,v 1.2 2014/12/08 03:45:00 bcook Exp $	*/
2/*
3 * Copyright (c) 2008 Otto Moerbeek <otto@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/* OPENBSD ORIGINAL: lib/libc/stdlib/reallocarray.c */
19
20#include "includes.h"
21#ifndef HAVE_REALLOCARRAY
22
23#include <sys/types.h>
24#include <errno.h>
25#ifdef HAVE_STDINT_H
26#include <stdint.h>
27#endif
28#include <stdlib.h>
29
30/*
31 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
32 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
33 */
34#define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))
35
36void *
37reallocarray(void *optr, size_t nmemb, size_t size)
38{
39	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
40	    nmemb > 0 && SIZE_MAX / nmemb < size) {
41		errno = ENOMEM;
42		return NULL;
43	}
44	return realloc(optr, size * nmemb);
45}
46#endif /* HAVE_REALLOCARRAY */
47