1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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/param.h> 30 #include <sys/auxv.h> 31 #include <sys/errno.h> 32 33 #include "libc_private.h" 34 35 /* 36 * Retrieves page size information from the system. Specifically, returns the 37 * number of distinct page sizes that are supported by the system, if 38 * "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of 39 * the system-supported page sizes to consecutive elements of the array 40 * referenced by "pagesize", and returns the number of such page sizes that it 41 * assigned to the array. These page sizes are expressed in bytes. 42 * 43 * The implementation of this function does not directly or indirectly call 44 * malloc(3) or any other dynamic memory allocator that may itself call this 45 * function. 46 */ 47 int 48 getpagesizes(size_t pagesize[], int nelem) 49 { 50 static u_long ps[MAXPAGESIZES]; 51 static int nops; 52 int i; 53 54 if (nelem < 0 || (nelem > 0 && pagesize == NULL)) { 55 errno = EINVAL; 56 return (-1); 57 } 58 /* Cache the result */ 59 if (nops == 0) { 60 if (_elf_aux_info(AT_PAGESIZES, ps, sizeof(ps)) != 0) 61 ps[0] = PAGE_SIZE; 62 /* Count the number of page sizes that are supported. */ 63 nops = nitems(ps); 64 while (nops > 0 && ps[nops - 1] == 0) 65 nops--; 66 } 67 if (pagesize == NULL) 68 return (nops); 69 /* Return up to "nelem" page sizes from the cached result. */ 70 if (nelem > nops) 71 nelem = nops; 72 for (i = 0; i < nelem; i++) 73 pagesize[i] = ps[i]; 74 return (nelem); 75 } 76