1 /* $NetBSD: aligned_alloc.c,v 1.2 2018/07/27 13:08:47 maya 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 <errno.h> 36 #include <stdlib.h> 37 38 void * 39 aligned_alloc(size_t alignment, size_t size) 40 { 41 void *memptr; 42 int err; 43 44 /* 45 * Check that alignment is a power of 2. 46 */ 47 if (alignment == 0 || ((alignment - 1) & alignment) != 0) { 48 errno = EINVAL; 49 return NULL; 50 } 51 52 /* 53 * Adjust alignment to satisfy posix_memalign, 54 * larger alignments satisfy smaller alignments. 55 */ 56 while (alignment < sizeof(void *)) { 57 alignment <<= 1; 58 } 59 60 err = posix_memalign(&memptr, alignment, size); 61 62 if (err) { 63 errno = err; 64 return NULL; 65 } 66 67 return memptr; 68 } 69