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
__weak_alias(reallocarr,_reallocarr)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
56 int
57 reallocarr(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