1/* $NetBSD: aligned_alloc.c,v 1.3 2024/08/18 18:47:20 riastradh Exp $ */
2
3/*-
4 * Copyright (C) 2015 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Niclas Rosenvik.
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(s), this list of conditions and the following disclaimer as
15 *    the first lines of this file unmodified other than the possible
16 *    addition of one or more copyright notices.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice(s), this list of conditions and the following disclaimer in
19 *    the documentation and/or other materials provided with the
20 *    distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
23 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
25 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
26 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
29 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
31 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
32 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36__RCSID("$NetBSD: aligned_alloc.c,v 1.3 2024/08/18 18:47:20 riastradh Exp $");
37
38#include <errno.h>
39#include <stdlib.h>
40
41void *
42aligned_alloc(size_t alignment, size_t size)
43{
44        void *memptr;
45        int err;
46
47        /*
48         * Check that alignment is a power of 2.
49         */
50        if (alignment == 0 || ((alignment - 1) & alignment) != 0) {
51                errno = EINVAL;
52                return NULL;
53        }
54
55        /*
56         * Adjust alignment to satisfy posix_memalign,
57         * larger alignments satisfy smaller alignments.
58         */
59        while (alignment < sizeof(void *)) {
60                alignment <<= 1;
61        }
62
63        err = posix_memalign(&memptr, alignment, size);
64        if (err) {
65                errno = err;
66                return NULL;
67        }
68
69        return memptr;
70}
71