1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. 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 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __SCCSID("@(#)getpagesize.c 8.1 (Berkeley) 6/4/93"); 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/param.h> 37 #include <sys/sysctl.h> 38 39 #include <errno.h> 40 #include <link.h> 41 #include <unistd.h> 42 43 #include "libc_private.h" 44 45 /* 46 * This is unlikely to change over the running time of any 47 * program, so we cache the result to save some syscalls. 48 * 49 * NB: This function may be called from malloc(3) at initialization 50 * NB: so must not result in a malloc(3) related call! 51 */ 52 53 int 54 getpagesize(void) 55 { 56 int mib[2]; 57 static int value; 58 size_t size; 59 int error; 60 61 if (value != 0) 62 return (value); 63 64 error = _elf_aux_info(AT_PAGESZ, &value, sizeof(value)); 65 if (error == 0 && value != 0) 66 return (value); 67 68 mib[0] = CTL_HW; 69 mib[1] = HW_PAGESIZE; 70 size = sizeof value; 71 if (sysctl(mib, nitems(mib), &value, &size, NULL, 0) == -1) 72 return (PAGE_SIZE); 73 74 return (value); 75 } 76