Function FUZZ_TARGET_INIT

src/test/fuzz/versionbits.cpp:113–363

constexpr uint32_t MAX_START_TIME = 4102444800; // 2100-01-01

FUZZ_TARGET_INIT(versionbits, initialize)
{
    const CChainParams& params = *g_params;
    const int64_t interval = params.GetConsensus().nPowTargetSpacing;
    assert(interval > 1); // need to be able to halve it
    assert(interval < std::numeric_limits<int32_t>::max());

    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());

    // making period/max_periods larger slows these tests down significantly
    const int period = 32;
    const size_t max_periods = 16;
    const size_t max_blocks = 2 * period * max_periods;

    const int threshold = fuzzed_data_provider.ConsumeIntegralInRange(1, period);
    assert(0 < threshold && threshold <= period); // must be able to both pass and fail threshold!

    // too many blocks at 10min each might cause uint32_t time to overflow if
    // block_start_time is at the end of the range above
    assert(std::numeric_limits<uint32_t>::max() - MAX_START_TIME > interval * max_blocks);

    const int64_t block_start_time = fuzzed_data_provider.ConsumeIntegralInRange<uint32_t>(params.GenesisBlock().nTime, MAX_START_TIME);

    // what values for version will we use to signal / not signal?
    const int32_t ver_signal = fuzzed_data_provider.ConsumeIntegral<int32_t>();
    const int32_t ver_nosignal = fuzzed_data_provider.ConsumeIntegral<int32_t>();

    // select deployment parameters: bit, start time, timeout
    const int bit = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, VERSIONBITS_NUM_BITS - 1);

    bool always_active_test = false;
    bool never_active_test = false;
    int64_t start_time;
    int64_t timeout;
    if (fuzzed_data_provider.ConsumeBool()) {
        // pick the timestamp to switch based on a block
        // note states will change *after* these blocks because mediantime lags
        int start_block = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, period * (max_periods - 3));
        int end_block = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, period * (max_periods - 3));

        start_time = block_start_time + start_block * interval;
        timeout = block_start_time + end_block * interval;

        // allow for times to not exactly match a block
        if (fuzzed_data_provider.ConsumeBool()) start_time += interval / 2;
        if (fuzzed_data_provider.ConsumeBool()) timeout += interval / 2;
    } else {
        if (fuzzed_data_provider.ConsumeBool()) {
            start_time = Consensus::BIP9Deployment::ALWAYS_ACTIVE;
            always_active_test = true;
        } else {
            start_time = Consensus::BIP9Deployment::NEVER_ACTIVE;
            never_active_test = true;
        }
        timeout = fuzzed_data_provider.ConsumeBool() ? Consensus::BIP9Deployment::NO_TIMEOUT : fuzzed_data_provider.ConsumeIntegral<int64_t>();
    }
    int min_activation = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, period * max_periods);