| // Copyright 2022 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "./fuzztest/internal/seed_seq.h" |
| |
| #include <algorithm> |
| #include <cstdint> |
| #include <cstdlib> |
| #include <cstring> |
| #include <optional> |
| #include <ostream> |
| #include <random> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/random/random.h" |
| #include "absl/strings/escaping.h" |
| #include "absl/strings/string_view.h" |
| #include "absl/types/span.h" |
| #include "./fuzztest/internal/logging.h" |
| |
| namespace fuzztest::internal { |
| namespace { |
| |
| std::vector<uint32_t> MakeSeedMaterial() { |
| absl::BitGen gen; |
| static constexpr int kNumberOfEntropyBits = 256; |
| std::vector<uint32_t> seed_material(kNumberOfEntropyBits / |
| (8 * sizeof(uint32_t))); |
| std::generate(seed_material.begin(), seed_material.end(), |
| [&gen] { return absl::Uniform<uint32_t>(gen); }); |
| return seed_material; |
| } |
| |
| std::vector<uint32_t> GetFromEnvOrMakeSeedMaterial(absl::string_view env_var) { |
| const char* encoded_seed_material = std::getenv(env_var.data()); |
| if (encoded_seed_material == nullptr) { |
| return MakeSeedMaterial(); |
| } |
| std::optional<std::vector<uint32_t>> seed_material = |
| DecodeSeedMaterial(encoded_seed_material); |
| FUZZTEST_INTERNAL_CHECK_PRECONDITION( |
| seed_material.has_value(), |
| "Failed to decode seed material from the environment variable ", env_var); |
| return *std::move(seed_material); |
| } |
| |
| } // namespace |
| |
| std::seed_seq GetFromEnvOrMakeSeedSeq(std::ostream& out, |
| absl::string_view env_var) { |
| const std::vector<uint32_t> seed_material = |
| GetFromEnvOrMakeSeedMaterial(env_var); |
| const std::string encoded_seed_material = EncodeSeedMaterial(seed_material); |
| out << env_var << "=" << encoded_seed_material << '\n'; |
| return std::seed_seq(seed_material.begin(), seed_material.end()); |
| } |
| |
| std::string EncodeSeedMaterial(absl::Span<const uint32_t> seed_material) { |
| return absl::WebSafeBase64Escape( |
| absl::string_view(reinterpret_cast<const char*>(seed_material.data()), |
| seed_material.size() * sizeof(uint32_t))); |
| } |
| |
| std::optional<std::vector<uint32_t>> DecodeSeedMaterial( |
| absl::string_view seed_material) { |
| std::string unescaped; |
| if (!absl::WebSafeBase64Unescape(seed_material, &unescaped)) |
| return std::nullopt; |
| |
| static constexpr auto kBlockSize = sizeof(uint32_t); |
| std::vector<uint32_t> decoded_seed_material( |
| (unescaped.size() + kBlockSize - 1) / kBlockSize); |
| memcpy(&decoded_seed_material[0], unescaped.data(), unescaped.size()); |
| return decoded_seed_material; |
| } |
| |
| } // namespace fuzztest::internal |