1/*	$NetBSD: rumpuser_random.c,v 1.3 2014/08/24 14:37:31 pooka Exp $	*/
2
3/*
4 * Copyright (c) 2014 Justin Cormack.  All Rights Reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include "rumpuser_port.h"
29
30#if !defined(lint)
31__RCSID("$NetBSD: rumpuser_random.c,v 1.3 2014/08/24 14:37:31 pooka Exp $");
32#endif /* !lint */
33
34#include <sys/types.h>
35
36#include <assert.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <stdint.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#include <rump/rumpuser.h>
46
47#include "rumpuser_int.h"
48
49static const size_t random_maxread = 32;
50
51#ifdef HAVE_ARC4RANDOM_BUF
52int
53rumpuser__random_init(void)
54{
55
56	return 0;
57}
58#else
59static const char *random_device = "/dev/urandom";
60static int random_fd = -1;
61
62int
63rumpuser__random_init(void)
64{
65
66	random_fd = open(random_device, O_RDONLY);
67	if (random_fd < 0) {
68		fprintf(stderr, "random init open failed\n");
69		return errno;
70	}
71	return 0;
72}
73#endif
74
75int
76rumpuser_getrandom(void *buf, size_t buflen, int flags, size_t *retp)
77{
78#ifndef HAVE_ARC4RANDOM_BUF
79	ssize_t rv;
80
81	rv = read(random_fd, buf, buflen > random_maxread ? random_maxread : buflen);
82	if (rv < 0) {
83		ET(errno);
84	}
85	*retp = rv;
86#else
87	buflen = buflen > random_maxread ? random_maxread : buflen;
88	arc4random_buf(buf, buflen);
89	*retp = buflen;
90#endif
91
92	return 0;
93}
94