target/mips/rel6_translate: Change license to GNU LGPL v2.1 (or later)
[qemu/ar7.git] / util / guest-random.c
blob086115bd67026c4ef7b7004d1915ecb2d8cd7fcb
1 /*
2 * QEMU guest-visible random functions
4 * Copyright 2019 Linaro, Ltd.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
12 #include "qemu/osdep.h"
13 #include "qemu/cutils.h"
14 #include "qapi/error.h"
15 #include "qemu/guest-random.h"
16 #include "crypto/random.h"
17 #include "sysemu/replay.h"
20 static __thread GRand *thread_rand;
21 static bool deterministic;
24 static int glib_random_bytes(void *buf, size_t len)
26 GRand *rand = thread_rand;
27 size_t i;
28 uint32_t x;
30 if (unlikely(rand == NULL)) {
31 /* Thread not initialized for a cpu, or main w/o -seed. */
32 thread_rand = rand = g_rand_new();
35 for (i = 0; i + 4 <= len; i += 4) {
36 x = g_rand_int(rand);
37 __builtin_memcpy(buf + i, &x, 4);
39 if (i < len) {
40 x = g_rand_int(rand);
41 __builtin_memcpy(buf + i, &x, i - len);
43 return 0;
46 int qemu_guest_getrandom(void *buf, size_t len, Error **errp)
48 int ret;
49 if (replay_mode == REPLAY_MODE_PLAY) {
50 return replay_read_random(buf, len);
52 if (unlikely(deterministic)) {
53 /* Deterministic implementation using Glib's Mersenne Twister. */
54 ret = glib_random_bytes(buf, len);
55 } else {
56 /* Non-deterministic implementation using crypto routines. */
57 ret = qcrypto_random_bytes(buf, len, errp);
59 if (replay_mode == REPLAY_MODE_RECORD) {
60 replay_save_random(ret, buf, len);
62 return ret;
65 void qemu_guest_getrandom_nofail(void *buf, size_t len)
67 (void)qemu_guest_getrandom(buf, len, &error_fatal);
70 uint64_t qemu_guest_random_seed_thread_part1(void)
72 if (deterministic) {
73 uint64_t ret;
74 glib_random_bytes(&ret, sizeof(ret));
75 return ret;
77 return 0;
80 void qemu_guest_random_seed_thread_part2(uint64_t seed)
82 g_assert(thread_rand == NULL);
83 if (deterministic) {
84 thread_rand =
85 g_rand_new_with_seed_array((const guint32 *)&seed,
86 sizeof(seed) / sizeof(guint32));
90 int qemu_guest_random_seed_main(const char *optarg, Error **errp)
92 unsigned long long seed;
93 if (parse_uint_full(optarg, &seed, 0)) {
94 error_setg(errp, "Invalid seed number: %s", optarg);
95 return -1;
96 } else {
97 deterministic = true;
98 qemu_guest_random_seed_thread_part2(seed);
99 return 0;