1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009 Alan L. Cox <alc@cs.rice.edu>
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/auxv.h>
31 #include <sys/errno.h>
32
33 #include "libc_private.h"
34
35 /*
36 * Retrieves page size information from the system. Specifically, returns the
37 * number of distinct page sizes that are supported by the system, if
38 * "pagesize" is NULL and "nelem" is 0. Otherwise, assigns up to "nelem" of
39 * the system-supported page sizes to consecutive elements of the array
40 * referenced by "pagesize", and returns the number of such page sizes that it
41 * assigned to the array. These page sizes are expressed in bytes.
42 *
43 * The implementation of this function does not directly or indirectly call
44 * malloc(3) or any other dynamic memory allocator that may itself call this
45 * function.
46 */
47 int
getpagesizes(size_t pagesize[],int nelem)48 getpagesizes(size_t pagesize[], int nelem)
49 {
50 static u_long ps[MAXPAGESIZES];
51 static int nops;
52 int i;
53
54 if (nelem < 0 || (nelem > 0 && pagesize == NULL)) {
55 errno = EINVAL;
56 return (-1);
57 }
58 /* Cache the result */
59 if (nops == 0) {
60 if (_elf_aux_info(AT_PAGESIZES, ps, sizeof(ps)) != 0)
61 ps[0] = PAGE_SIZE;
62 /* Count the number of page sizes that are supported. */
63 nops = nitems(ps);
64 while (nops > 0 && ps[nops - 1] == 0)
65 nops--;
66 }
67 if (pagesize == NULL)
68 return (nops);
69 /* Return up to "nelem" page sizes from the cached result. */
70 if (nelem > nops)
71 nelem = nops;
72 for (i = 0; i < nelem; i++)
73 pagesize[i] = ps[i];
74 return (nelem);
75 }
76