1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009 Alan L. Cox <alc@cs.rice.edu> 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 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD$"); 31 32#include <sys/param.h> 33#include <sys/mman.h> 34#include <sys/sysctl.h> 35 36#include <errno.h> 37#include <link.h> 38 39#include "libc_private.h" 40 41/* 42 * Retrieves page size information from the system. Specifically, returns the 43 * number of distinct page sizes that are supported by the system, if 44 * "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of 45 * the system-supported page sizes to consecutive elements of the array 46 * referenced by "pagesize", and returns the number of such page sizes that it 47 * assigned to the array. These page sizes are expressed in bytes. 48 * 49 * The implementation of this function does not directly or indirectly call 50 * malloc(3) or any other dynamic memory allocator that may itself call this 51 * function. 52 */ 53int 54getpagesizes(size_t pagesize[], int nelem) 55{ 56 static u_long ps[MAXPAGESIZES]; 57 static int nops; 58 size_t size; 59 int error, i; 60 61 if (nelem < 0 || (nelem > 0 && pagesize == NULL)) { 62 errno = EINVAL; 63 return (-1); 64 } 65 /* Cache the result of the sysctl(2). */ 66 if (nops == 0) { 67 error = _elf_aux_info(AT_PAGESIZES, ps, sizeof(ps)); 68 size = sizeof(ps); 69 if (error != 0 || ps[0] == 0) { 70 if (sysctlbyname("hw.pagesizes", ps, &size, NULL, 0) 71 == -1) 72 return (-1); 73 } 74 /* Count the number of page sizes that are supported. */ 75 nops = size / sizeof(ps[0]); 76 while (nops > 0 && ps[nops - 1] == 0) 77 nops--; 78 } 79 if (pagesize == NULL) 80 return (nops); 81 /* Return up to "nelem" page sizes from the cached result. */ 82 if (nelem > nops) 83 nelem = nops; 84 for (i = 0; i < nelem; i++) 85 pagesize[i] = ps[i]; 86 return (nelem); 87} 88