1/* $NetBSD: reallocarr.c,v 1.5 2015/08/20 22:27:49 kamil Exp $ */
2
3/*-
4 * Copyright (c) 2015 Joerg Sonnenberger <joerg@NetBSD.org>.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in
15 *    the documentation and/or other materials provided with the
16 *    distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
28 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if HAVE_NBTOOL_CONFIG_H
33#include "nbtool_config.h"
34#endif
35
36#include <sys/cdefs.h>
37__RCSID("$NetBSD: reallocarr.c,v 1.5 2015/08/20 22:27:49 kamil Exp $");
38
39#include "namespace.h"
40#include <errno.h>
41/* Old POSIX has SIZE_MAX in limits.h */
42#include <limits.h>
43#include <stdint.h>
44#include <stdlib.h>
45#include <string.h>
46
47#ifdef _LIBC
48#ifdef __weak_alias
49__weak_alias(reallocarr, _reallocarr)
50#endif
51#endif
52
53#define SQRT_SIZE_MAX (((size_t)1) << (sizeof(size_t) * CHAR_BIT / 2))
54
55#if !HAVE_REALLOCARR
56int
57reallocarr(void *ptr, size_t number, size_t size)
58{
59	int saved_errno, result;
60	void *optr;
61	void *nptr;
62
63	saved_errno = errno;
64	memcpy(&optr, ptr, sizeof(ptr));
65	if (number == 0 || size == 0) {
66		free(optr);
67		nptr = NULL;
68		memcpy(ptr, &nptr, sizeof(ptr));
69		errno = saved_errno;
70		return 0;
71	}
72
73	/*
74	 * Try to avoid division here.
75	 *
76	 * It isn't possible to overflow during multiplication if neither
77	 * operand uses any of the most significant half of the bits.
78	 */
79	if (__predict_false((number|size) >= SQRT_SIZE_MAX &&
80	                    number > SIZE_MAX / size)) {
81		errno = saved_errno;
82		return EOVERFLOW;
83	}
84
85	nptr = realloc(optr, number * size);
86	if (__predict_false(nptr == NULL)) {
87		result = errno;
88	} else {
89		result = 0;
90		memcpy(ptr, &nptr, sizeof(ptr));
91	}
92	errno = saved_errno;
93	return result;
94}
95#endif
96