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
41 void *
aligned_alloc(size_t alignment,size_t size)42 aligned_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