Branch data     Line data    Source code

       1                 :             : // Copyright (c) 2023 The Bitcoin Core developers
       2                 :             : // Distributed under the MIT software license, see the accompanying
       3                 :             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4                 :             : 
       5                 :             : #include <test/util/random.h>
       6                 :             : 
       7                 :             : #include <logging.h>
       8                 :             : #include <random.h>
       9                 :             : #include <uint256.h>
      10                 :             : #include <util/check.h>
      11                 :             : 
      12                 :             : #include <cstdlib>
      13                 :             : #include <iostream>
      14                 :             : 
      15                 :             : std::atomic<bool> g_seeded_g_prng_zero{false};
      16                 :             : 
      17                 :             : extern void MakeRandDeterministicDANGEROUS(const uint256& seed) noexcept;
      18                 :             : 
      19                 :         621 : void SeedRandomStateForTest(SeedRand seedtype)
      20                 :             : {
      21                 :         621 :     constexpr auto RANDOM_CTX_SEED{"RANDOM_CTX_SEED"};
      22                 :             : 
      23                 :             :     // Do this once, on the first call, regardless of seedtype, because once
      24                 :             :     // MakeRandDeterministicDANGEROUS is called, the output of GetRandHash is
      25                 :             :     // no longer truly random. It should be enough to get the seed once for the
      26                 :             :     // process.
      27                 :         726 :     static const uint256 ctx_seed = []() {
      28                 :             :         // If RANDOM_CTX_SEED is set, use that as seed.
      29         [ -  + ]:         105 :         if (const char* num{std::getenv(RANDOM_CTX_SEED)}) {
      30         [ #  # ]:           0 :             if (auto num_parsed{uint256::FromUserHex(num)}) {
      31                 :           0 :                 return *num_parsed;
      32                 :             :             } else {
      33                 :           0 :                 std::cerr << RANDOM_CTX_SEED << " must consist of up to " << uint256::size() * 2 << " hex digits (\"0x\" prefix allowed), it was set to: '" << num << "'.\n";
      34                 :           0 :                 std::abort();
      35                 :             :             }
      36                 :             :         }
      37                 :             :         // Otherwise use a (truly) random value.
      38                 :         105 :         return GetRandHash();
      39   [ +  +  +  -  :         621 :     }();
                   +  - ]
      40                 :             : 
      41         [ +  + ]:         621 :     g_seeded_g_prng_zero = seedtype == SeedRand::ZEROS;
      42                 :         621 :     if constexpr (G_FUZZING) {
      43                 :             :         Assert(g_seeded_g_prng_zero); // Only SeedRandomStateForTest(SeedRand::ZEROS) is allowed in fuzz tests
      44                 :             :     }
      45         [ +  + ]:         621 :     const uint256& seed{seedtype == SeedRand::FIXED_SEED ? ctx_seed : uint256::ZERO};
      46         [ +  - ]:         621 :     LogInfo("Setting random seed for current tests to %s=%s\n", RANDOM_CTX_SEED, seed.GetHex());
      47                 :         621 :     MakeRandDeterministicDANGEROUS(seed);
      48                 :         621 : }