1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009 Alan L. Cox <[email protected]>
5 * 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/mman.h>
31 #include <sys/sysctl.h>
32
33 #include <errno.h>
34 #include <link.h>
35
36 #include "libc_private.h"
37
38 /*
39 * Retrieves page size information from the system. Specifically, returns the
40 * number of distinct page sizes that are supported by the system, if
41 * "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of
42 * the system-supported page sizes to consecutive elements of the array
43 * referenced by "pagesize", and returns the number of such page sizes that it
44 * assigned to the array. These page sizes are expressed in bytes.
45 *
46 * The implementation of this function does not directly or indirectly call
47 * malloc(3) or any other dynamic memory allocator that may itself call this
48 * function.
49 */
50 int
getpagesizes(size_t pagesize[],int nelem)51 getpagesizes(size_t pagesize[], int nelem)
52 {
53 static u_long ps[MAXPAGESIZES];
54 static int nops;
55 size_t size;
56 int error, i;
57
58 if (nelem < 0 || (nelem > 0 && pagesize == NULL)) {
59 errno = EINVAL;
60 return (-1);
61 }
62 /* Cache the result of the sysctl(2). */
63 if (nops == 0) {
64 error = _elf_aux_info(AT_PAGESIZES, ps, sizeof(ps));
65 size = sizeof(ps);
66 if (error != 0 || ps[0] == 0) {
67 if (sysctlbyname("hw.pagesizes", ps, &size, NULL, 0)
68 == -1)
69 return (-1);
70 }
71 /* Count the number of page sizes that are supported. */
72 nops = size / sizeof(ps[0]);
73 while (nops > 0 && ps[nops - 1] == 0)
74 nops--;
75 }
76 if (pagesize == NULL)
77 return (nops);
78 /* Return up to "nelem" page sizes from the cached result. */
79 if (nelem > nops)
80 nelem = nops;
81 for (i = 0; i < nelem; i++)
82 pagesize[i] = ps[i];
83 return (nelem);
84 }
85