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freebsd/lib/libc/gen/getpagesizes.c
Konstantin Belousov 2793b01844 Use aux vector to get values for SSP canary, pagesize, pagesizes array,
number of host CPUs and osreldate.

This eliminates the last sysctl(2) calls from the dynamically linked image
startup.

No objections from:	kan
Tested by:	marius (sparc64)
MFC after:	1 month
2010-08-17 09:13:26 +00:00

86 lines
2.9 KiB
C

/*-
* Copyright (c) 2009 Alan L. Cox <alc@cs.rice.edu>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <link.h>
#include "libc_private.h"
/*
* Retrieves page size information from the system. Specifically, returns the
* number of distinct page sizes that are supported by the system, if
* "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of
* the system-supported page sizes to consecutive elements of the array
* referenced by "pagesize", and returns the number of such page sizes that it
* assigned to the array. These page sizes are expressed in bytes.
*
* The implementation of this function does not directly or indirectly call
* malloc(3) or any other dynamic memory allocator that may itself call this
* function.
*/
int
getpagesizes(size_t pagesize[], int nelem)
{
static u_long ps[MAXPAGESIZES];
static int nops;
size_t size;
int error, i;
if (nelem < 0 || (nelem > 0 && pagesize == NULL)) {
errno = EINVAL;
return (-1);
}
/* Cache the result of the sysctl(2). */
if (nops == 0) {
error = _elf_aux_info(AT_PAGESIZES, ps, sizeof(ps));
size = sizeof(ps);
if (error != 0 || ps[0] == 0) {
if (sysctlbyname("hw.pagesizes", ps, &size, NULL, 0)
== -1)
return (-1);
}
/* Count the number of page sizes that are supported. */
nops = size / sizeof(ps[0]);
while (nops > 0 && ps[nops - 1] == 0)
nops--;
}
if (pagesize == NULL)
return (nops);
/* Return up to "nelem" page sizes from the cached result. */
if (nelem > nops)
nelem = nops;
for (i = 0; i < nelem; i++)
pagesize[i] = ps[i];
return (nelem);
}