freebsd-skq/lib/libc/gen/getpagesize.c
kib b9ba3d19a1 getpagesize(3) cannot fail.
The sysctl(HW_PAGESIZE) call cannot fail on FreeBSD kernels at least.
And even if it failed for some improbable reason, PAGE_SIZE is a safe
value to return.

Discussed with:	jilles
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2017-04-26 14:25:01 +00:00

76 lines
2.5 KiB
C

/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getpagesize.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <link.h>
#include <unistd.h>
#include "libc_private.h"
/*
* This is unlikely to change over the running time of any
* program, so we cache the result to save some syscalls.
*
* NB: This function may be called from malloc(3) at initialization
* NB: so must not result in a malloc(3) related call!
*/
int
getpagesize(void)
{
int mib[2];
static int value;
size_t size;
int error;
if (value != 0)
return (value);
error = _elf_aux_info(AT_PAGESZ, &value, sizeof(value));
if (error == 0 && value != 0)
return (value);
mib[0] = CTL_HW;
mib[1] = HW_PAGESIZE;
size = sizeof value;
if (sysctl(mib, nitems(mib), &value, &size, NULL, 0) == -1)
return (PAGE_SIZE);
return (value);
}