1/*
2 * Copyright 2012-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <folly/Random.h>
18
19#include <algorithm>
20#include <random>
21#include <thread>
22#include <unordered_set>
23#include <vector>
24
25#include <glog/logging.h>
26
27#include <folly/portability/GTest.h>
28
29using namespace folly;
30
31TEST(Random, StateSize) {
32 using namespace folly::detail;
33
34 // uint_fast32_t is uint64_t on x86_64, w00t
35 EXPECT_EQ(
36 sizeof(uint_fast32_t) / 4 + 3, StateSizeT<std::minstd_rand0>::value);
37 EXPECT_EQ(624, StateSizeT<std::mt19937>::value);
38#if FOLLY_HAVE_EXTRANDOM_SFMT19937
39 EXPECT_EQ(624, StateSizeT<__gnu_cxx::sfmt19937>::value);
40#endif
41 EXPECT_EQ(24, StateSizeT<std::ranlux24_base>::value);
42}
43
44TEST(Random, Simple) {
45 uint32_t prev = 0, seed = 0;
46 for (int i = 0; i < 1024; ++i) {
47 EXPECT_NE(seed = randomNumberSeed(), prev);
48 prev = seed;
49 }
50}
51
52TEST(Random, FixedSeed) {
53 // clang-format off
54 struct ConstantRNG {
55 typedef uint32_t result_type;
56 result_type operator()() {
57 return 4; // chosen by fair dice roll.
58 // guaranteed to be random.
59 }
60 static constexpr result_type min() {
61 return std::numeric_limits<result_type>::min();
62 }
63 static constexpr result_type max() {
64 return std::numeric_limits<result_type>::max();
65 }
66 };
67 // clang-format on
68
69 ConstantRNG gen;
70
71 // Pick a constant random number...
72 auto value = Random::rand32(10, gen);
73
74 // Loop to make sure it really is constant.
75 for (int i = 0; i < 1024; ++i) {
76 auto result = Random::rand32(10, gen);
77 EXPECT_EQ(value, result);
78 }
79}
80
81TEST(Random, MultiThreaded) {
82 const int n = 100;
83 std::vector<uint32_t> seeds(n);
84 std::vector<std::thread> threads;
85 for (int i = 0; i < n; ++i) {
86 threads.push_back(
87 std::thread([i, &seeds] { seeds[i] = randomNumberSeed(); }));
88 }
89 for (auto& t : threads) {
90 t.join();
91 }
92 std::sort(seeds.begin(), seeds.end());
93 for (int i = 0; i < n - 1; ++i) {
94 EXPECT_LT(seeds[i], seeds[i + 1]);
95 }
96}
97
98TEST(Random, sanity) {
99 // edge cases
100 EXPECT_EQ(folly::Random::rand32(0), 0);
101 EXPECT_EQ(folly::Random::rand32(12, 12), 0);
102 EXPECT_EQ(folly::Random::rand64(0), 0);
103 EXPECT_EQ(folly::Random::rand64(12, 12), 0);
104
105 // 32-bit repeatability, uniqueness
106 constexpr int kTestSize = 1000;
107 {
108 std::vector<uint32_t> vals;
109 folly::Random::DefaultGenerator rng;
110 rng.seed(0xdeadbeef);
111 for (int i = 0; i < kTestSize; ++i) {
112 vals.push_back(folly::Random::rand32(rng));
113 }
114 rng.seed(0xdeadbeef);
115 for (int i = 0; i < kTestSize; ++i) {
116 EXPECT_EQ(vals[i], folly::Random::rand32(rng));
117 }
118 EXPECT_EQ(
119 vals.size(),
120 std::unordered_set<uint32_t>(vals.begin(), vals.end()).size());
121 }
122
123 // 64-bit repeatability, uniqueness
124 {
125 std::vector<uint64_t> vals;
126 folly::Random::DefaultGenerator rng;
127 rng.seed(0xdeadbeef);
128 for (int i = 0; i < kTestSize; ++i) {
129 vals.push_back(folly::Random::rand64(rng));
130 }
131 rng.seed(0xdeadbeef);
132 for (int i = 0; i < kTestSize; ++i) {
133 EXPECT_EQ(vals[i], folly::Random::rand64(rng));
134 }
135 EXPECT_EQ(
136 vals.size(),
137 std::unordered_set<uint64_t>(vals.begin(), vals.end()).size());
138 }
139}
140
141#ifndef _WIN32
142TEST(Random, SecureFork) {
143 // Random buffer size is 128, must be less than that.
144 int retries = 100;
145 while (true) {
146 unsigned char buffer = 0;
147 // Init random buffer
148 folly::Random::secureRandom(&buffer, 1);
149
150 auto pid = fork();
151 EXPECT_NE(pid, -1);
152 if (pid) {
153 // parent
154 int status = 0;
155 folly::Random::secureRandom(&buffer, 1);
156 auto pid2 = wait(&status);
157 EXPECT_EQ(pid, pid2);
158 // Since this *is* random data, we could randomly end up with
159 // the same byte. Try again a few times if so before assuming
160 // real failure.
161 if (WEXITSTATUS(status) == buffer && retries-- > 0) {
162 continue;
163 }
164 EXPECT_NE(WEXITSTATUS(status), buffer);
165 return;
166 } else {
167 // child
168 folly::Random::secureRandom(&buffer, 1);
169 exit(buffer); // Do not print gtest results
170 }
171 }
172}
173#endif
174