mirror of
https://github.com/bitcoin/bitcoin.git
synced 2026-01-19 14:53:43 +01:00
c1d01f59ac
When building with BUILD_FOR_FUZZING=OFF BUILD_FUZZ_BINARY=ON CMAKE_BUILD_TYPE=Debug allow the fuzz binary to execute given test cases (without actual fuzzing) to make it easier to reproduce fuzz test failures in a more normal debug build. In Debug builds, deterministic fuzz behaviour is controlled via a runtime variable, which is normally false, but set to true automatically in the fuzz binary, unless the FUZZ_NONDETERMINISM environment variable is set.
51 lines
2.0 KiB
C++
51 lines
2.0 KiB
C++
// Copyright (c) 2023-present The Bitcoin Core developers
|
|
// Distributed under the MIT software license, see the accompanying
|
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
#include <test/util/random.h>
|
|
|
|
#include <logging.h>
|
|
#include <random.h>
|
|
#include <uint256.h>
|
|
#include <util/check.h>
|
|
|
|
#include <cstdlib>
|
|
#include <iostream>
|
|
|
|
std::atomic<bool> g_seeded_g_prng_zero{false};
|
|
|
|
extern void MakeRandDeterministicDANGEROUS(const uint256& seed) noexcept;
|
|
|
|
void SeedRandomStateForTest(SeedRand seedtype)
|
|
{
|
|
constexpr auto RANDOM_CTX_SEED{"RANDOM_CTX_SEED"};
|
|
|
|
// Do this once, on the first call, regardless of seedtype, because once
|
|
// MakeRandDeterministicDANGEROUS is called, the output of GetRandHash is
|
|
// no longer truly random. It should be enough to get the seed once for the
|
|
// process.
|
|
static const auto g_ctx_seed = []() -> std::optional<uint256> {
|
|
if (EnableFuzzDeterminism()) return {};
|
|
// If RANDOM_CTX_SEED is set, use that as seed.
|
|
if (const char* num{std::getenv(RANDOM_CTX_SEED)}) {
|
|
if (auto num_parsed{uint256::FromUserHex(num)}) {
|
|
return *num_parsed;
|
|
} else {
|
|
std::cerr << RANDOM_CTX_SEED << " must consist of up to " << uint256::size() * 2 << " hex digits (\"0x\" prefix allowed), it was set to: '" << num << "'.\n";
|
|
std::abort();
|
|
}
|
|
}
|
|
// Otherwise use a (truly) random value.
|
|
return GetRandHash();
|
|
}();
|
|
|
|
g_seeded_g_prng_zero = seedtype == SeedRand::ZEROS;
|
|
if (EnableFuzzDeterminism()) {
|
|
Assert(g_seeded_g_prng_zero); // Only SeedRandomStateForTest(SeedRand::ZEROS) is allowed in fuzz tests
|
|
Assert(!g_used_g_prng); // The global PRNG must not have been used before SeedRandomStateForTest(SeedRand::ZEROS)
|
|
}
|
|
const uint256& seed{seedtype == SeedRand::FIXED_SEED ? g_ctx_seed.value() : uint256::ZERO};
|
|
LogInfo("Setting random seed for current tests to %s=%s\n", RANDOM_CTX_SEED, seed.GetHex());
|
|
MakeRandDeterministicDANGEROUS(seed);
|
|
}
|