1 /* $NetBSD: getentropy.c,v 1.3 2022/05/31 13:42:59 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2020 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Nia Alarie.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: getentropy.c,v 1.3 2022/05/31 13:42:59 riastradh Exp $");
34
35 #include "namespace.h"
36
37 #include <sys/param.h>
38 #include <sys/sysctl.h>
39
40 #include <errno.h>
41 #include <limits.h>
42 #include <unistd.h>
43
44 #ifdef __weak_alias
45 __weak_alias(getentropy,_getentropy)
46 #endif
47
48 __CTASSERT(GETENTROPY_MAX == 256);
49
50 int
getentropy(void * buf,size_t buflen)51 getentropy(void *buf, size_t buflen)
52 {
53 size_t len = buflen;
54 int name[2] = { CTL_KERN, KERN_ARND };
55
56 if (buf == NULL && buflen > 0) {
57 errno = EFAULT;
58 return -1;
59 }
60
61 if (buflen > 256) {
62 errno = EINVAL;
63 return -1;
64 }
65
66 return sysctl(name, 2, buf, &len, NULL, 0);
67 }
68