xref: /netbsd/lib/libc/gen/getpagesize.c (revision 6550d01e)
1 /*	$NetBSD: getpagesize.c,v 1.10 2009/12/14 01:04:46 matt Exp $	*/
2 
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 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)getpagesize.c	8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: getpagesize.c,v 1.10 2009/12/14 01:04:46 matt Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include "namespace.h"
42 #include <sys/param.h>
43 #include <sys/sysctl.h>
44 #include <assert.h>
45 #include <unistd.h>
46 
47 #ifdef __weak_alias
48 __weak_alias(getpagesize,_getpagesize)
49 #endif
50 
51 int
52 getpagesize()
53 {
54 	static int pagsz;
55 
56 	if (pagsz == 0) {
57 		int mib[2];
58 		size_t size;
59 
60 		mib[0] = CTL_HW;
61 		mib[1] = HW_PAGESIZE;
62 		size = sizeof pagsz;
63 		if (sysctl(mib, 2, &pagsz, &size, NULL, 0) == -1)
64 			return (-1);
65 		_DIAGASSERT(pagsz);
66 	}
67 	return (pagsz);
68 }
69