2 * Copyright (c) 2009 Alan L. Cox <alc@cs.rice.edu>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
32 #include <sys/sysctl.h>
37 * Retrieves page size information from the system. Specifically, returns the
38 * number of distinct page sizes that are supported by the system, if
39 * "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of
40 * the system-supported page sizes to consecutive elements of the array
41 * referenced by "pagesize", and returns the number of such page sizes that it
42 * assigned to the array. These page sizes are expressed in bytes.
44 * The implementation of this function does not directly or indirectly call
45 * malloc(3) or any other dynamic memory allocator that may itself call this
49 getpagesizes(size_t pagesize[], int nelem)
51 static u_long ps[MAXPAGESIZES];
56 if (nelem < 0 || (nelem > 0 && pagesize == NULL)) {
60 /* Cache the result of the sysctl(2). */
63 if (sysctlbyname("hw.pagesizes", ps, &size, NULL, 0) == -1)
65 /* Count the number of page sizes that are supported. */
66 nops = size / sizeof(ps[0]);
67 while (nops > 0 && ps[nops - 1] == 0)
72 /* Return up to "nelem" page sizes from the cached result. */
75 for (i = 0; i < nelem; i++)