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 #include <sys/param.h>
35 #include <sys/sysctl.h>
36
37 #include <errno.h>
38 #include <link.h>
39 #include <unistd.h>
40
41 #include "libc_private.h"
42
43 /*
44 * This is unlikely to change over the running time of any
45 * program, so we cache the result to save some syscalls.
46 *
47 * NB: This function may be called from malloc(3) at initialization
48 * NB: so must not result in a malloc(3) related call!
49 */
50
51 int
getpagesize(void)52 getpagesize(void)
53 {
54 int mib[2];
55 static int value;
56 size_t size;
57 int error;
58
59 if (value != 0)
60 return (value);
61
62 error = _elf_aux_info(AT_PAGESZ, &value, sizeof(value));
63 if (error == 0 && value != 0)
64 return (value);
65
66 mib[0] = CTL_HW;
67 mib[1] = HW_PAGESIZE;
68 size = sizeof value;
69 if (sysctl(mib, nitems(mib), &value, &size, NULL, 0) == -1)
70 return (PAGE_SIZE);
71
72 return (value);
73 }
74