aa35c4db08
sizes or some number of the sizes themselves. It is functionally compatible with a function by the same name under Solaris. Reviewed by: jhb
79 lines
2.8 KiB
C
79 lines
2.8 KiB
C
/*-
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* Copyright (c) 2009 Alan L. Cox <alc@cs.rice.edu>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <sys/sysctl.h>
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#include <errno.h>
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/*
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* Retrieves page size information from the system. Specifically, returns the
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* number of distinct page sizes that are supported by the system, if
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* "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of
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* the system-supported page sizes to consecutive elements of the array
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* referenced by "pagesize", and returns the number of such page sizes that it
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* assigned to the array. These page sizes are expressed in bytes.
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*
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* The implementation of this function does not directly or indirectly call
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* malloc(3) or any other dynamic memory allocator that may itself call this
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* function.
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*/
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int
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getpagesizes(size_t pagesize[], int nelem)
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{
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static u_long ps[MAXPAGESIZES];
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static int nops;
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size_t size;
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int i;
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if (nelem < 0 || (nelem > 0 && pagesize == NULL)) {
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errno = EINVAL;
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return (-1);
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}
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/* Cache the result of the sysctl(2). */
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if (nops == 0) {
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size = sizeof(ps);
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if (sysctlbyname("hw.pagesizes", ps, &size, NULL, 0) == -1)
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return (-1);
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/* Count the number of page sizes that are supported. */
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nops = size / sizeof(ps[0]);
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while (nops > 0 && ps[nops - 1] == 0)
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nops--;
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}
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if (pagesize == NULL)
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return (nops);
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/* Return up to "nelem" page sizes from the cached result. */
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if (nelem > nops)
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nelem = nops;
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for (i = 0; i < nelem; i++)
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pagesize[i] = ps[i];
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return (nelem);
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}
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