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Diffstat (limited to 'src/validation.cpp')
| -rw-r--r-- | src/validation.cpp | 5225 |
1 files changed, 5225 insertions, 0 deletions
diff --git a/src/validation.cpp b/src/validation.cpp new file mode 100644 index 0000000000..b5d6a66088 --- /dev/null +++ b/src/validation.cpp @@ -0,0 +1,5225 @@ +// Copyright (c) 2009-2010 Satoshi Nakamoto +// Copyright (c) 2009-2021 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 <validation.h> + +#include <arith_uint256.h> +#include <chain.h> +#include <chainparams.h> +#include <checkqueue.h> +#include <consensus/amount.h> +#include <consensus/consensus.h> +#include <consensus/merkle.h> +#include <consensus/tx_check.h> +#include <consensus/tx_verify.h> +#include <consensus/validation.h> +#include <cuckoocache.h> +#include <deploymentstatus.h> +#include <flatfile.h> +#include <hash.h> +#include <logging.h> +#include <logging/timer.h> +#include <node/blockstorage.h> +#include <node/coinstats.h> +#include <node/ui_interface.h> +#include <node/utxo_snapshot.h> +#include <policy/policy.h> +#include <policy/rbf.h> +#include <policy/settings.h> +#include <pow.h> +#include <primitives/block.h> +#include <primitives/transaction.h> +#include <random.h> +#include <reverse_iterator.h> +#include <script/script.h> +#include <script/sigcache.h> +#include <shutdown.h> +#include <signet.h> +#include <timedata.h> +#include <tinyformat.h> +#include <txdb.h> +#include <txmempool.h> +#include <uint256.h> +#include <undo.h> +#include <util/check.h> // For NDEBUG compile time check +#include <util/hasher.h> +#include <util/moneystr.h> +#include <util/rbf.h> +#include <util/strencodings.h> +#include <util/system.h> +#include <util/trace.h> +#include <util/translation.h> +#include <validationinterface.h> +#include <warnings.h> + +#include <algorithm> +#include <deque> +#include <numeric> +#include <optional> +#include <string> + +using node::BLOCKFILE_CHUNK_SIZE; +using node::BlockManager; +using node::BlockMap; +using node::CBlockIndexHeightOnlyComparator; +using node::CBlockIndexWorkComparator; +using node::CCoinsStats; +using node::CoinStatsHashType; +using node::fImporting; +using node::fPruneMode; +using node::fReindex; +using node::GetUTXOStats; +using node::nPruneTarget; +using node::OpenBlockFile; +using node::ReadBlockFromDisk; +using node::SnapshotMetadata; +using node::UNDOFILE_CHUNK_SIZE; +using node::UndoReadFromDisk; +using node::UnlinkPrunedFiles; + +#define MICRO 0.000001 +#define MILLI 0.001 + +/** + * An extra transaction can be added to a package, as long as it only has one + * ancestor and is no larger than this. Not really any reason to make this + * configurable as it doesn't materially change DoS parameters. + */ +static const unsigned int EXTRA_DESCENDANT_TX_SIZE_LIMIT = 10000; +/** Maximum kilobytes for transactions to store for processing during reorg */ +static const unsigned int MAX_DISCONNECTED_TX_POOL_SIZE = 20000; +/** Time to wait between writing blocks/block index to disk. */ +static constexpr std::chrono::hours DATABASE_WRITE_INTERVAL{1}; +/** Time to wait between flushing chainstate to disk. */ +static constexpr std::chrono::hours DATABASE_FLUSH_INTERVAL{24}; +/** Maximum age of our tip for us to be considered current for fee estimation */ +static constexpr std::chrono::hours MAX_FEE_ESTIMATION_TIP_AGE{3}; +const std::vector<std::string> CHECKLEVEL_DOC { + "level 0 reads the blocks from disk", + "level 1 verifies block validity", + "level 2 verifies undo data", + "level 3 checks disconnection of tip blocks", + "level 4 tries to reconnect the blocks", + "each level includes the checks of the previous levels", +}; +/** The number of blocks to keep below the deepest prune lock. + * There is nothing special about this number. It is higher than what we + * expect to see in regular mainnet reorgs, but not so high that it would + * noticeably interfere with the pruning mechanism. + * */ +static constexpr int PRUNE_LOCK_BUFFER{10}; + +/** + * Mutex to guard access to validation specific variables, such as reading + * or changing the chainstate. + * + * This may also need to be locked when updating the transaction pool, e.g. on + * AcceptToMemoryPool. See CTxMemPool::cs comment for details. + * + * The transaction pool has a separate lock to allow reading from it and the + * chainstate at the same time. + */ +RecursiveMutex cs_main; + +Mutex g_best_block_mutex; +std::condition_variable g_best_block_cv; +uint256 g_best_block; +bool g_parallel_script_checks{false}; +bool fRequireStandard = true; +bool fCheckBlockIndex = false; +bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED; +int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE; + +uint256 hashAssumeValid; +arith_uint256 nMinimumChainWork; + +CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE); + +const CBlockIndex* CChainState::FindForkInGlobalIndex(const CBlockLocator& locator) const +{ + AssertLockHeld(cs_main); + + // Find the latest block common to locator and chain - we expect that + // locator.vHave is sorted descending by height. + for (const uint256& hash : locator.vHave) { + const CBlockIndex* pindex{m_blockman.LookupBlockIndex(hash)}; + if (pindex) { + if (m_chain.Contains(pindex)) { + return pindex; + } + if (pindex->GetAncestor(m_chain.Height()) == m_chain.Tip()) { + return m_chain.Tip(); + } + } + } + return m_chain.Genesis(); +} + +bool CheckInputScripts(const CTransaction& tx, TxValidationState& state, + const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore, + bool cacheFullScriptStore, PrecomputedTransactionData& txdata, + std::vector<CScriptCheck>* pvChecks = nullptr) + EXCLUSIVE_LOCKS_REQUIRED(cs_main); + +bool CheckFinalTxAtTip(const CBlockIndex* active_chain_tip, const CTransaction& tx) +{ + AssertLockHeld(cs_main); + assert(active_chain_tip); // TODO: Make active_chain_tip a reference + + // CheckFinalTxAtTip() uses active_chain_tip.Height()+1 to evaluate + // nLockTime because when IsFinalTx() is called within + // AcceptBlock(), the height of the block *being* + // evaluated is what is used. Thus if we want to know if a + // transaction can be part of the *next* block, we need to call + // IsFinalTx() with one more than active_chain_tip.Height(). + const int nBlockHeight = active_chain_tip->nHeight + 1; + + // BIP113 requires that time-locked transactions have nLockTime set to + // less than the median time of the previous block they're contained in. + // When the next block is created its previous block will be the current + // chain tip, so we use that to calculate the median time passed to + // IsFinalTx(). + const int64_t nBlockTime{active_chain_tip->GetMedianTimePast()}; + + return IsFinalTx(tx, nBlockHeight, nBlockTime); +} + +bool CheckSequenceLocksAtTip(CBlockIndex* tip, + const CCoinsView& coins_view, + const CTransaction& tx, + LockPoints* lp, + bool useExistingLockPoints) +{ + assert(tip != nullptr); + + CBlockIndex index; + index.pprev = tip; + // CheckSequenceLocksAtTip() uses active_chainstate.m_chain.Height()+1 to evaluate + // height based locks because when SequenceLocks() is called within + // ConnectBlock(), the height of the block *being* + // evaluated is what is used. + // Thus if we want to know if a transaction can be part of the + // *next* block, we need to use one more than active_chainstate.m_chain.Height() + index.nHeight = tip->nHeight + 1; + + std::pair<int, int64_t> lockPair; + if (useExistingLockPoints) { + assert(lp); + lockPair.first = lp->height; + lockPair.second = lp->time; + } + else { + std::vector<int> prevheights; + prevheights.resize(tx.vin.size()); + for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) { + const CTxIn& txin = tx.vin[txinIndex]; + Coin coin; + if (!coins_view.GetCoin(txin.prevout, coin)) { + return error("%s: Missing input", __func__); + } + if (coin.nHeight == MEMPOOL_HEIGHT) { + // Assume all mempool transaction confirm in the next block + prevheights[txinIndex] = tip->nHeight + 1; + } else { + prevheights[txinIndex] = coin.nHeight; + } + } + lockPair = CalculateSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, prevheights, index); + if (lp) { + lp->height = lockPair.first; + lp->time = lockPair.second; + // Also store the hash of the block with the highest height of + // all the blocks which have sequence locked prevouts. + // This hash needs to still be on the chain + // for these LockPoint calculations to be valid + // Note: It is impossible to correctly calculate a maxInputBlock + // if any of the sequence locked inputs depend on unconfirmed txs, + // except in the special case where the relative lock time/height + // is 0, which is equivalent to no sequence lock. Since we assume + // input height of tip+1 for mempool txs and test the resulting + // lockPair from CalculateSequenceLocks against tip+1. We know + // EvaluateSequenceLocks will fail if there was a non-zero sequence + // lock on a mempool input, so we can use the return value of + // CheckSequenceLocksAtTip to indicate the LockPoints validity + int maxInputHeight = 0; + for (const int height : prevheights) { + // Can ignore mempool inputs since we'll fail if they had non-zero locks + if (height != tip->nHeight+1) { + maxInputHeight = std::max(maxInputHeight, height); + } + } + // tip->GetAncestor(maxInputHeight) should never return a nullptr + // because maxInputHeight is always less than the tip height. + // It would, however, be a bad bug to continue execution, since a + // LockPoints object with the maxInputBlock member set to nullptr + // signifies no relative lock time. + lp->maxInputBlock = Assert(tip->GetAncestor(maxInputHeight)); + } + } + return EvaluateSequenceLocks(index, lockPair); +} + +// Returns the script flags which should be checked for a given block +static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const Consensus::Params& chainparams); + +static void LimitMempoolSize(CTxMemPool& pool, CCoinsViewCache& coins_cache, size_t limit, std::chrono::seconds age) + EXCLUSIVE_LOCKS_REQUIRED(::cs_main, pool.cs) +{ + AssertLockHeld(::cs_main); + AssertLockHeld(pool.cs); + int expired = pool.Expire(GetTime<std::chrono::seconds>() - age); + if (expired != 0) { + LogPrint(BCLog::MEMPOOL, "Expired %i transactions from the memory pool\n", expired); + } + + std::vector<COutPoint> vNoSpendsRemaining; + pool.TrimToSize(limit, &vNoSpendsRemaining); + for (const COutPoint& removed : vNoSpendsRemaining) + coins_cache.Uncache(removed); +} + +static bool IsCurrentForFeeEstimation(CChainState& active_chainstate) EXCLUSIVE_LOCKS_REQUIRED(cs_main) +{ + AssertLockHeld(cs_main); + if (active_chainstate.IsInitialBlockDownload()) + return false; + if (active_chainstate.m_chain.Tip()->GetBlockTime() < count_seconds(GetTime<std::chrono::seconds>() - MAX_FEE_ESTIMATION_TIP_AGE)) + return false; + if (active_chainstate.m_chain.Height() < active_chainstate.m_chainman.m_best_header->nHeight - 1) { + return false; + } + return true; +} + +void CChainState::MaybeUpdateMempoolForReorg( + DisconnectedBlockTransactions& disconnectpool, + bool fAddToMempool) +{ + if (!m_mempool) return; + + AssertLockHeld(cs_main); + AssertLockHeld(m_mempool->cs); + std::vector<uint256> vHashUpdate; + // disconnectpool's insertion_order index sorts the entries from + // oldest to newest, but the oldest entry will be the last tx from the + // latest mined block that was disconnected. + // Iterate disconnectpool in reverse, so that we add transactions + // back to the mempool starting with the earliest transaction that had + // been previously seen in a block. + auto it = disconnectpool.queuedTx.get<insertion_order>().rbegin(); + while (it != disconnectpool.queuedTx.get<insertion_order>().rend()) { + // ignore validation errors in resurrected transactions + if (!fAddToMempool || (*it)->IsCoinBase() || + AcceptToMemoryPool(*this, *it, GetTime(), + /*bypass_limits=*/true, /*test_accept=*/false).m_result_type != + MempoolAcceptResult::ResultType::VALID) { + // If the transaction doesn't make it in to the mempool, remove any + // transactions that depend on it (which would now be orphans). + m_mempool->removeRecursive(**it, MemPoolRemovalReason::REORG); + } else if (m_mempool->exists(GenTxid::Txid((*it)->GetHash()))) { + vHashUpdate.push_back((*it)->GetHash()); + } + ++it; + } + disconnectpool.queuedTx.clear(); + // AcceptToMemoryPool/addUnchecked all assume that new mempool entries have + // no in-mempool children, which is generally not true when adding + // previously-confirmed transactions back to the mempool. + // UpdateTransactionsFromBlock finds descendants of any transactions in + // the disconnectpool that were added back and cleans up the mempool state. + const uint64_t ancestor_count_limit = gArgs.GetIntArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT); + const uint64_t ancestor_size_limit = gArgs.GetIntArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT) * 1000; + m_mempool->UpdateTransactionsFromBlock(vHashUpdate, ancestor_size_limit, ancestor_count_limit); + + // Predicate to use for filtering transactions in removeForReorg. + // Checks whether the transaction is still final and, if it spends a coinbase output, mature. + // Also updates valid entries' cached LockPoints if needed. + // If false, the tx is still valid and its lockpoints are updated. + // If true, the tx would be invalid in the next block; remove this entry and all of its descendants. + const auto filter_final_and_mature = [this](CTxMemPool::txiter it) + EXCLUSIVE_LOCKS_REQUIRED(m_mempool->cs, ::cs_main) { + AssertLockHeld(m_mempool->cs); + AssertLockHeld(::cs_main); + const CTransaction& tx = it->GetTx(); + + // The transaction must be final. + if (!CheckFinalTxAtTip(m_chain.Tip(), tx)) return true; + LockPoints lp = it->GetLockPoints(); + const bool validLP{TestLockPointValidity(m_chain, lp)}; + CCoinsViewMemPool view_mempool(&CoinsTip(), *m_mempool); + // CheckSequenceLocksAtTip checks if the transaction will be final in the next block to be + // created on top of the new chain. We use useExistingLockPoints=false so that, instead of + // using the information in lp (which might now refer to a block that no longer exists in + // the chain), it will update lp to contain LockPoints relevant to the new chain. + if (!CheckSequenceLocksAtTip(m_chain.Tip(), view_mempool, tx, &lp, validLP)) { + // If CheckSequenceLocksAtTip fails, remove the tx and don't depend on the LockPoints. + return true; + } else if (!validLP) { + // If CheckSequenceLocksAtTip succeeded, it also updated the LockPoints. + // Now update the mempool entry lockpoints as well. + m_mempool->mapTx.modify(it, [&lp](CTxMemPoolEntry& e) { e.UpdateLockPoints(lp); }); + } + + // If the transaction spends any coinbase outputs, it must be mature. + if (it->GetSpendsCoinbase()) { + for (const CTxIn& txin : tx.vin) { + auto it2 = m_mempool->mapTx.find(txin.prevout.hash); + if (it2 != m_mempool->mapTx.end()) + continue; + const Coin& coin{CoinsTip().AccessCoin(txin.prevout)}; + assert(!coin.IsSpent()); + const auto mempool_spend_height{m_chain.Tip()->nHeight + 1}; + if (coin.IsCoinBase() && mempool_spend_height - coin.nHeight < COINBASE_MATURITY) { + return true; + } + } + } + // Transaction is still valid and cached LockPoints are updated. + return false; + }; + + // We also need to remove any now-immature transactions + m_mempool->removeForReorg(m_chain, filter_final_and_mature); + // Re-limit mempool size, in case we added any transactions + LimitMempoolSize( + *m_mempool, + this->CoinsTip(), + gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, + std::chrono::hours{gArgs.GetIntArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)}); +} + +/** +* Checks to avoid mempool polluting consensus critical paths since cached +* signature and script validity results will be reused if we validate this +* transaction again during block validation. +* */ +static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, TxValidationState& state, + const CCoinsViewCache& view, const CTxMemPool& pool, + unsigned int flags, PrecomputedTransactionData& txdata, CCoinsViewCache& coins_tip) + EXCLUSIVE_LOCKS_REQUIRED(cs_main, pool.cs) +{ + AssertLockHeld(cs_main); + AssertLockHeld(pool.cs); + + assert(!tx.IsCoinBase()); + for (const CTxIn& txin : tx.vin) { + const Coin& coin = view.AccessCoin(txin.prevout); + + // This coin was checked in PreChecks and MemPoolAccept + // has been holding cs_main since then. + Assume(!coin.IsSpent()); + if (coin.IsSpent()) return false; + + // If the Coin is available, there are 2 possibilities: + // it is available in our current ChainstateActive UTXO set, + // or it's a UTXO provided by a transaction in our mempool. + // Ensure the scriptPubKeys in Coins from CoinsView are correct. + const CTransactionRef& txFrom = pool.get(txin.prevout.hash); + if (txFrom) { + assert(txFrom->GetHash() == txin.prevout.hash); + assert(txFrom->vout.size() > txin.prevout.n); + assert(txFrom->vout[txin.prevout.n] == coin.out); + } else { + const Coin& coinFromUTXOSet = coins_tip.AccessCoin(txin.prevout); + assert(!coinFromUTXOSet.IsSpent()); + assert(coinFromUTXOSet.out == coin.out); + } + } + + // Call CheckInputScripts() to cache signature and script validity against current tip consensus rules. + return CheckInputScripts(tx, state, view, flags, /* cacheSigStore= */ true, /* cacheFullScriptStore= */ true, txdata); +} + +namespace { + +class MemPoolAccept +{ +public: + explicit MemPoolAccept(CTxMemPool& mempool, CChainState& active_chainstate) : m_pool(mempool), m_view(&m_dummy), m_viewmempool(&active_chainstate.CoinsTip(), m_pool), m_active_chainstate(active_chainstate), + m_limit_ancestors(gArgs.GetIntArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT)), + m_limit_ancestor_size(gArgs.GetIntArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT)*1000), + m_limit_descendants(gArgs.GetIntArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT)), + m_limit_descendant_size(gArgs.GetIntArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT)*1000) { + } + + // We put the arguments we're handed into a struct, so we can pass them + // around easier. + struct ATMPArgs { + const CChainParams& m_chainparams; + const int64_t m_accept_time; + const bool m_bypass_limits; + /* + * Return any outpoints which were not previously present in the coins + * cache, but were added as a result of validating the tx for mempool + * acceptance. This allows the caller to optionally remove the cache + * additions if the associated transaction ends up being rejected by + * the mempool. + */ + std::vector<COutPoint>& m_coins_to_uncache; + const bool m_test_accept; + /** Whether we allow transactions to replace mempool transactions by BIP125 rules. If false, + * any transaction spending the same inputs as a transaction in the mempool is considered + * a conflict. */ + const bool m_allow_bip125_replacement; + /** When true, the mempool will not be trimmed when individual transactions are submitted in + * Finalize(). Instead, limits should be enforced at the end to ensure the package is not + * partially submitted. + */ + const bool m_package_submission; + /** When true, use package feerates instead of individual transaction feerates for fee-based + * policies such as mempool min fee and min relay fee. + */ + const bool m_package_feerates; + + /** Parameters for single transaction mempool validation. */ + static ATMPArgs SingleAccept(const CChainParams& chainparams, int64_t accept_time, + bool bypass_limits, std::vector<COutPoint>& coins_to_uncache, + bool test_accept) { + return ATMPArgs{/* m_chainparams */ chainparams, + /* m_accept_time */ accept_time, + /* m_bypass_limits */ bypass_limits, + /* m_coins_to_uncache */ coins_to_uncache, + /* m_test_accept */ test_accept, + /* m_allow_bip125_replacement */ true, + /* m_package_submission */ false, + /* m_package_feerates */ false, + }; + } + + /** Parameters for test package mempool validation through testmempoolaccept. */ + static ATMPArgs PackageTestAccept(const CChainParams& chainparams, int64_t accept_time, + std::vector<COutPoint>& coins_to_uncache) { + return ATMPArgs{/* m_chainparams */ chainparams, + /* m_accept_time */ accept_time, + /* m_bypass_limits */ false, + /* m_coins_to_uncache */ coins_to_uncache, + /* m_test_accept */ true, + /* m_allow_bip125_replacement */ false, + /* m_package_submission */ false, // not submitting to mempool + /* m_package_feerates */ false, + }; + } + + /** Parameters for child-with-unconfirmed-parents package validation. */ + static ATMPArgs PackageChildWithParents(const CChainParams& chainparams, int64_t accept_time, + std::vector<COutPoint>& coins_to_uncache) { + return ATMPArgs{/* m_chainparams */ chainparams, + /* m_accept_time */ accept_time, + /* m_bypass_limits */ false, + /* m_coins_to_uncache */ coins_to_uncache, + /* m_test_accept */ false, + /* m_allow_bip125_replacement */ false, + /* m_package_submission */ true, + /* m_package_feerates */ true, + }; + } + + /** Parameters for a single transaction within a package. */ + static ATMPArgs SingleInPackageAccept(const ATMPArgs& package_args) { + return ATMPArgs{/* m_chainparams */ package_args.m_chainparams, + /* m_accept_time */ package_args.m_accept_time, + /* m_bypass_limits */ false, + /* m_coins_to_uncache */ package_args.m_coins_to_uncache, + /* m_test_accept */ package_args.m_test_accept, + /* m_allow_bip125_replacement */ true, + /* m_package_submission */ false, + /* m_package_feerates */ false, // only 1 transaction + }; + } + + private: + // Private ctor to avoid exposing details to clients and allowing the possibility of + // mixing up the order of the arguments. Use static functions above instead. + ATMPArgs(const CChainParams& chainparams, + int64_t accept_time, + bool bypass_limits, + std::vector<COutPoint>& coins_to_uncache, + bool test_accept, + bool allow_bip125_replacement, + bool package_submission, + bool package_feerates) + : m_chainparams{chainparams}, + m_accept_time{accept_time}, + m_bypass_limits{bypass_limits}, + m_coins_to_uncache{coins_to_uncache}, + m_test_accept{test_accept}, + m_allow_bip125_replacement{allow_bip125_replacement}, + m_package_submission{package_submission}, + m_package_feerates{package_feerates} + { + } + }; + + // Single transaction acceptance + MempoolAcceptResult AcceptSingleTransaction(const CTransactionRef& ptx, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main); + + /** + * Multiple transaction acceptance. Transactions may or may not be interdependent, but must not + * conflict with each other, and the transactions cannot already be in the mempool. Parents must + * come before children if any dependencies exist. + */ + PackageMempoolAcceptResult AcceptMultipleTransactions(const std::vector<CTransactionRef>& txns, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main); + + /** + * Package (more specific than just multiple transactions) acceptance. Package must be a child + * with all of its unconfirmed parents, and topologically sorted. + */ + PackageMempoolAcceptResult AcceptPackage(const Package& package, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main); + +private: + // All the intermediate state that gets passed between the various levels + // of checking a given transaction. + struct Workspace { + explicit Workspace(const CTransactionRef& ptx) : m_ptx(ptx), m_hash(ptx->GetHash()) {} + /** Txids of mempool transactions that this transaction directly conflicts with. */ + std::set<uint256> m_conflicts; + /** Iterators to mempool entries that this transaction directly conflicts with. */ + CTxMemPool::setEntries m_iters_conflicting; + /** Iterators to all mempool entries that would be replaced by this transaction, including + * those it directly conflicts with and their descendants. */ + CTxMemPool::setEntries m_all_conflicting; + /** All mempool ancestors of this transaction. */ + CTxMemPool::setEntries m_ancestors; + /** Mempool entry constructed for this transaction. Constructed in PreChecks() but not + * inserted into the mempool until Finalize(). */ + std::unique_ptr<CTxMemPoolEntry> m_entry; + /** Pointers to the transactions that have been removed from the mempool and replaced by + * this transaction, used to return to the MemPoolAccept caller. Only populated if + * validation is successful and the original transactions are removed. */ + std::list<CTransactionRef> m_replaced_transactions; + + /** Virtual size of the transaction as used by the mempool, calculated using serialized size + * of the transaction and sigops. */ + int64_t m_vsize; + /** Fees paid by this transaction: total input amounts subtracted by total output amounts. */ + CAmount m_base_fees; + /** Base fees + any fee delta set by the user with prioritisetransaction. */ + CAmount m_modified_fees; + /** Total modified fees of all transactions being replaced. */ + CAmount m_conflicting_fees{0}; + /** Total virtual size of all transactions being replaced. */ + size_t m_conflicting_size{0}; + + const CTransactionRef& m_ptx; + /** Txid. */ + const uint256& m_hash; + TxValidationState m_state; + /** A temporary cache containing serialized transaction data for signature verification. + * Reused across PolicyScriptChecks and ConsensusScriptChecks. */ + PrecomputedTransactionData m_precomputed_txdata; + }; + + // Run the policy checks on a given transaction, excluding any script checks. + // Looks up inputs, calculates feerate, considers replacement, evaluates + // package limits, etc. As this function can be invoked for "free" by a peer, + // only tests that are fast should be done here (to avoid CPU DoS). + bool PreChecks(ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Run checks for mempool replace-by-fee. + bool ReplacementChecks(Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Enforce package mempool ancestor/descendant limits (distinct from individual + // ancestor/descendant limits done in PreChecks). + bool PackageMempoolChecks(const std::vector<CTransactionRef>& txns, + PackageValidationState& package_state) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Run the script checks using our policy flags. As this can be slow, we should + // only invoke this on transactions that have otherwise passed policy checks. + bool PolicyScriptChecks(const ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Re-run the script checks, using consensus flags, and try to cache the + // result in the scriptcache. This should be done after + // PolicyScriptChecks(). This requires that all inputs either be in our + // utxo set or in the mempool. + bool ConsensusScriptChecks(const ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Try to add the transaction to the mempool, removing any conflicts first. + // Returns true if the transaction is in the mempool after any size + // limiting is performed, false otherwise. + bool Finalize(const ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Submit all transactions to the mempool and call ConsensusScriptChecks to add to the script + // cache - should only be called after successful validation of all transactions in the package. + // The package may end up partially-submitted after size limiting; returns true if all + // transactions are successfully added to the mempool, false otherwise. + bool SubmitPackage(const ATMPArgs& args, std::vector<Workspace>& workspaces, PackageValidationState& package_state, + std::map<const uint256, const MempoolAcceptResult>& results) + EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); + + // Compare a package's feerate against minimum allowed. + bool CheckFeeRate(size_t package_size, CAmount package_fee, TxValidationState& state) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_pool.cs) + { + AssertLockHeld(::cs_main); + AssertLockHeld(m_pool.cs); + CAmount mempoolRejectFee = m_pool.GetMinFee(gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(package_size); + if (mempoolRejectFee > 0 && package_fee < mempoolRejectFee) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "mempool min fee not met", strprintf("%d < %d", package_fee, mempoolRejectFee)); + } + + if (package_fee < ::minRelayTxFee.GetFee(package_size)) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "min relay fee not met", strprintf("%d < %d", package_fee, ::minRelayTxFee.GetFee(package_size))); + } + return true; + } + +private: + CTxMemPool& m_pool; + CCoinsViewCache m_view; + CCoinsViewMemPool m_viewmempool; + CCoinsView m_dummy; + + CChainState& m_active_chainstate; + + // The package limits in effect at the time of invocation. + const size_t m_limit_ancestors; + const size_t m_limit_ancestor_size; + // These may be modified while evaluating a transaction (eg to account for + // in-mempool conflicts; see below). + size_t m_limit_descendants; + size_t m_limit_descendant_size; + + /** Whether the transaction(s) would replace any mempool transactions. If so, RBF rules apply. */ + bool m_rbf{false}; +}; + +bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + const CTransactionRef& ptx = ws.m_ptx; + const CTransaction& tx = *ws.m_ptx; + const uint256& hash = ws.m_hash; + + // Copy/alias what we need out of args + const int64_t nAcceptTime = args.m_accept_time; + const bool bypass_limits = args.m_bypass_limits; + std::vector<COutPoint>& coins_to_uncache = args.m_coins_to_uncache; + + // Alias what we need out of ws + TxValidationState& state = ws.m_state; + std::unique_ptr<CTxMemPoolEntry>& entry = ws.m_entry; + + if (!CheckTransaction(tx, state)) { + return false; // state filled in by CheckTransaction + } + + // Coinbase is only valid in a block, not as a loose transaction + if (tx.IsCoinBase()) + return state.Invalid(TxValidationResult::TX_CONSENSUS, "coinbase"); + + // Rather not work on nonstandard transactions (unless -testnet/-regtest) + std::string reason; + if (fRequireStandard && !IsStandardTx(tx, reason)) + return state.Invalid(TxValidationResult::TX_NOT_STANDARD, reason); + + // Do not work on transactions that are too small. + // A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes. + // Transactions smaller than this are not relayed to mitigate CVE-2017-12842 by not relaying + // 64-byte transactions. + if (::GetSerializeSize(tx, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) < MIN_STANDARD_TX_NONWITNESS_SIZE) + return state.Invalid(TxValidationResult::TX_NOT_STANDARD, "tx-size-small"); + + // Only accept nLockTime-using transactions that can be mined in the next + // block; we don't want our mempool filled up with transactions that can't + // be mined yet. + if (!CheckFinalTxAtTip(m_active_chainstate.m_chain.Tip(), tx)) { + return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-final"); + } + + if (m_pool.exists(GenTxid::Wtxid(tx.GetWitnessHash()))) { + // Exact transaction already exists in the mempool. + return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-already-in-mempool"); + } else if (m_pool.exists(GenTxid::Txid(tx.GetHash()))) { + // Transaction with the same non-witness data but different witness (same txid, different + // wtxid) already exists in the mempool. + return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-same-nonwitness-data-in-mempool"); + } + + // Check for conflicts with in-memory transactions + for (const CTxIn &txin : tx.vin) + { + const CTransaction* ptxConflicting = m_pool.GetConflictTx(txin.prevout); + if (ptxConflicting) { + if (!args.m_allow_bip125_replacement) { + // Transaction conflicts with a mempool tx, but we're not allowing replacements. + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "bip125-replacement-disallowed"); + } + if (!ws.m_conflicts.count(ptxConflicting->GetHash())) + { + // Transactions that don't explicitly signal replaceability are + // *not* replaceable with the current logic, even if one of their + // unconfirmed ancestors signals replaceability. This diverges + // from BIP125's inherited signaling description (see CVE-2021-31876). + // Applications relying on first-seen mempool behavior should + // check all unconfirmed ancestors; otherwise an opt-in ancestor + // might be replaced, causing removal of this descendant. + if (!SignalsOptInRBF(*ptxConflicting)) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "txn-mempool-conflict"); + } + + ws.m_conflicts.insert(ptxConflicting->GetHash()); + } + } + } + + LockPoints lp; + m_view.SetBackend(m_viewmempool); + + const CCoinsViewCache& coins_cache = m_active_chainstate.CoinsTip(); + // do all inputs exist? + for (const CTxIn& txin : tx.vin) { + if (!coins_cache.HaveCoinInCache(txin.prevout)) { + coins_to_uncache.push_back(txin.prevout); + } + + // Note: this call may add txin.prevout to the coins cache + // (coins_cache.cacheCoins) by way of FetchCoin(). It should be removed + // later (via coins_to_uncache) if this tx turns out to be invalid. + if (!m_view.HaveCoin(txin.prevout)) { + // Are inputs missing because we already have the tx? + for (size_t out = 0; out < tx.vout.size(); out++) { + // Optimistically just do efficient check of cache for outputs + if (coins_cache.HaveCoinInCache(COutPoint(hash, out))) { + return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-already-known"); + } + } + // Otherwise assume this might be an orphan tx for which we just haven't seen parents yet + return state.Invalid(TxValidationResult::TX_MISSING_INPUTS, "bad-txns-inputs-missingorspent"); + } + } + + // This is const, but calls into the back end CoinsViews. The CCoinsViewDB at the bottom of the + // hierarchy brings the best block into scope. See CCoinsViewDB::GetBestBlock(). + m_view.GetBestBlock(); + + // we have all inputs cached now, so switch back to dummy (to protect + // against bugs where we pull more inputs from disk that miss being added + // to coins_to_uncache) + m_view.SetBackend(m_dummy); + + assert(m_active_chainstate.m_blockman.LookupBlockIndex(m_view.GetBestBlock()) == m_active_chainstate.m_chain.Tip()); + + // Only accept BIP68 sequence locked transactions that can be mined in the next + // block; we don't want our mempool filled up with transactions that can't + // be mined yet. + // Pass in m_view which has all of the relevant inputs cached. Note that, since m_view's + // backend was removed, it no longer pulls coins from the mempool. + if (!CheckSequenceLocksAtTip(m_active_chainstate.m_chain.Tip(), m_view, tx, &lp)) { + return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-BIP68-final"); + } + + // The mempool holds txs for the next block, so pass height+1 to CheckTxInputs + if (!Consensus::CheckTxInputs(tx, state, m_view, m_active_chainstate.m_chain.Height() + 1, ws.m_base_fees)) { + return false; // state filled in by CheckTxInputs + } + + // Check for non-standard pay-to-script-hash in inputs + if (fRequireStandard && !AreInputsStandard(tx, m_view)) { + return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "bad-txns-nonstandard-inputs"); + } + + // Check for non-standard witnesses. + if (tx.HasWitness() && fRequireStandard && !IsWitnessStandard(tx, m_view)) + return state.Invalid(TxValidationResult::TX_WITNESS_MUTATED, "bad-witness-nonstandard"); + + int64_t nSigOpsCost = GetTransactionSigOpCost(tx, m_view, STANDARD_SCRIPT_VERIFY_FLAGS); + + // ws.m_modified_fees includes any fee deltas from PrioritiseTransaction + ws.m_modified_fees = ws.m_base_fees; + m_pool.ApplyDelta(hash, ws.m_modified_fees); + + // Keep track of transactions that spend a coinbase, which we re-scan + // during reorgs to ensure COINBASE_MATURITY is still met. + bool fSpendsCoinbase = false; + for (const CTxIn &txin : tx.vin) { + const Coin &coin = m_view.AccessCoin(txin.prevout); + if (coin.IsCoinBase()) { + fSpendsCoinbase = true; + break; + } + } + + entry.reset(new CTxMemPoolEntry(ptx, ws.m_base_fees, nAcceptTime, m_active_chainstate.m_chain.Height(), + fSpendsCoinbase, nSigOpsCost, lp)); + ws.m_vsize = entry->GetTxSize(); + + if (nSigOpsCost > MAX_STANDARD_TX_SIGOPS_COST) + return state.Invalid(TxValidationResult::TX_NOT_STANDARD, "bad-txns-too-many-sigops", + strprintf("%d", nSigOpsCost)); + + // No individual transactions are allowed below minRelayTxFee and mempool min fee except from + // disconnected blocks and transactions in a package. Package transactions will be checked using + // package feerate later. + if (!bypass_limits && !args.m_package_feerates && !CheckFeeRate(ws.m_vsize, ws.m_modified_fees, state)) return false; + + ws.m_iters_conflicting = m_pool.GetIterSet(ws.m_conflicts); + // Calculate in-mempool ancestors, up to a limit. + if (ws.m_conflicts.size() == 1) { + // In general, when we receive an RBF transaction with mempool conflicts, we want to know whether we + // would meet the chain limits after the conflicts have been removed. However, there isn't a practical + // way to do this short of calculating the ancestor and descendant sets with an overlay cache of + // changed mempool entries. Due to both implementation and runtime complexity concerns, this isn't + // very realistic, thus we only ensure a limited set of transactions are RBF'able despite mempool + // conflicts here. Importantly, we need to ensure that some transactions which were accepted using + // the below carve-out are able to be RBF'ed, without impacting the security the carve-out provides + // for off-chain contract systems (see link in the comment below). + // + // Specifically, the subset of RBF transactions which we allow despite chain limits are those which + // conflict directly with exactly one other transaction (but may evict children of said transaction), + // and which are not adding any new mempool dependencies. Note that the "no new mempool dependencies" + // check is accomplished later, so we don't bother doing anything about it here, but if BIP 125 is + // amended, we may need to move that check to here instead of removing it wholesale. + // + // Such transactions are clearly not merging any existing packages, so we are only concerned with + // ensuring that (a) no package is growing past the package size (not count) limits and (b) we are + // not allowing something to effectively use the (below) carve-out spot when it shouldn't be allowed + // to. + // + // To check these we first check if we meet the RBF criteria, above, and increment the descendant + // limits by the direct conflict and its descendants (as these are recalculated in + // CalculateMempoolAncestors by assuming the new transaction being added is a new descendant, with no + // removals, of each parent's existing dependent set). The ancestor count limits are unmodified (as + // the ancestor limits should be the same for both our new transaction and any conflicts). + // We don't bother incrementing m_limit_descendants by the full removal count as that limit never comes + // into force here (as we're only adding a single transaction). + assert(ws.m_iters_conflicting.size() == 1); + CTxMemPool::txiter conflict = *ws.m_iters_conflicting.begin(); + + m_limit_descendants += 1; + m_limit_descendant_size += conflict->GetSizeWithDescendants(); + } + + std::string errString; + if (!m_pool.CalculateMemPoolAncestors(*entry, ws.m_ancestors, m_limit_ancestors, m_limit_ancestor_size, m_limit_descendants, m_limit_descendant_size, errString)) { + ws.m_ancestors.clear(); + // If CalculateMemPoolAncestors fails second time, we want the original error string. + std::string dummy_err_string; + // Contracting/payment channels CPFP carve-out: + // If the new transaction is relatively small (up to 40k weight) + // and has at most one ancestor (ie ancestor limit of 2, including + // the new transaction), allow it if its parent has exactly the + // descendant limit descendants. + // + // This allows protocols which rely on distrusting counterparties + // being able to broadcast descendants of an unconfirmed transaction + // to be secure by simply only having two immediately-spendable + // outputs - one for each counterparty. For more info on the uses for + // this, see https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html + if (ws.m_vsize > EXTRA_DESCENDANT_TX_SIZE_LIMIT || + !m_pool.CalculateMemPoolAncestors(*entry, ws.m_ancestors, 2, m_limit_ancestor_size, m_limit_descendants + 1, m_limit_descendant_size + EXTRA_DESCENDANT_TX_SIZE_LIMIT, dummy_err_string)) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too-long-mempool-chain", errString); + } + } + + // A transaction that spends outputs that would be replaced by it is invalid. Now + // that we have the set of all ancestors we can detect this + // pathological case by making sure ws.m_conflicts and ws.m_ancestors don't + // intersect. + if (const auto err_string{EntriesAndTxidsDisjoint(ws.m_ancestors, ws.m_conflicts, hash)}) { + // We classify this as a consensus error because a transaction depending on something it + // conflicts with would be inconsistent. + return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-spends-conflicting-tx", *err_string); + } + + m_rbf = !ws.m_conflicts.empty(); + return true; +} + +bool MemPoolAccept::ReplacementChecks(Workspace& ws) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + + const CTransaction& tx = *ws.m_ptx; + const uint256& hash = ws.m_hash; + TxValidationState& state = ws.m_state; + + CFeeRate newFeeRate(ws.m_modified_fees, ws.m_vsize); + // The replacement transaction must have a higher feerate than its direct conflicts. + // - The motivation for this check is to ensure that the replacement transaction is preferable for + // block-inclusion, compared to what would be removed from the mempool. + // - This logic predates ancestor feerate-based transaction selection, which is why it doesn't + // consider feerates of descendants. + // - Note: Ancestor feerate-based transaction selection has made this comparison insufficient to + // guarantee that this is incentive-compatible for miners, because it is possible for a + // descendant transaction of a direct conflict to pay a higher feerate than the transaction that + // might replace them, under these rules. + if (const auto err_string{PaysMoreThanConflicts(ws.m_iters_conflicting, newFeeRate, hash)}) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string); + } + + // Calculate all conflicting entries and enforce BIP125 Rule #5. + if (const auto err_string{GetEntriesForConflicts(tx, m_pool, ws.m_iters_conflicting, ws.m_all_conflicting)}) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, + "too many potential replacements", *err_string); + } + // Enforce BIP125 Rule #2. + if (const auto err_string{HasNoNewUnconfirmed(tx, m_pool, ws.m_iters_conflicting)}) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, + "replacement-adds-unconfirmed", *err_string); + } + // Check if it's economically rational to mine this transaction rather than the ones it + // replaces and pays for its own relay fees. Enforce BIP125 Rules #3 and #4. + for (CTxMemPool::txiter it : ws.m_all_conflicting) { + ws.m_conflicting_fees += it->GetModifiedFee(); + ws.m_conflicting_size += it->GetTxSize(); + } + if (const auto err_string{PaysForRBF(ws.m_conflicting_fees, ws.m_modified_fees, ws.m_vsize, + ::incrementalRelayFee, hash)}) { + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string); + } + return true; +} + +bool MemPoolAccept::PackageMempoolChecks(const std::vector<CTransactionRef>& txns, + PackageValidationState& package_state) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + + // CheckPackageLimits expects the package transactions to not already be in the mempool. + assert(std::all_of(txns.cbegin(), txns.cend(), [this](const auto& tx) + { return !m_pool.exists(GenTxid::Txid(tx->GetHash()));})); + + std::string err_string; + if (!m_pool.CheckPackageLimits(txns, m_limit_ancestors, m_limit_ancestor_size, m_limit_descendants, + m_limit_descendant_size, err_string)) { + // This is a package-wide error, separate from an individual transaction error. + return package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-mempool-limits", err_string); + } + return true; +} + +bool MemPoolAccept::PolicyScriptChecks(const ATMPArgs& args, Workspace& ws) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + const CTransaction& tx = *ws.m_ptx; + TxValidationState& state = ws.m_state; + + constexpr unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS; + + // Check input scripts and signatures. + // This is done last to help prevent CPU exhaustion denial-of-service attacks. + if (!CheckInputScripts(tx, state, m_view, scriptVerifyFlags, true, false, ws.m_precomputed_txdata)) { + // SCRIPT_VERIFY_CLEANSTACK requires SCRIPT_VERIFY_WITNESS, so we + // need to turn both off, and compare against just turning off CLEANSTACK + // to see if the failure is specifically due to witness validation. + TxValidationState state_dummy; // Want reported failures to be from first CheckInputScripts + if (!tx.HasWitness() && CheckInputScripts(tx, state_dummy, m_view, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, false, ws.m_precomputed_txdata) && + !CheckInputScripts(tx, state_dummy, m_view, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, ws.m_precomputed_txdata)) { + // Only the witness is missing, so the transaction itself may be fine. + state.Invalid(TxValidationResult::TX_WITNESS_STRIPPED, + state.GetRejectReason(), state.GetDebugMessage()); + } + return false; // state filled in by CheckInputScripts + } + + return true; +} + +bool MemPoolAccept::ConsensusScriptChecks(const ATMPArgs& args, Workspace& ws) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + const CTransaction& tx = *ws.m_ptx; + const uint256& hash = ws.m_hash; + TxValidationState& state = ws.m_state; + const CChainParams& chainparams = args.m_chainparams; + + // Check again against the current block tip's script verification + // flags to cache our script execution flags. This is, of course, + // useless if the next block has different script flags from the + // previous one, but because the cache tracks script flags for us it + // will auto-invalidate and we'll just have a few blocks of extra + // misses on soft-fork activation. + // + // This is also useful in case of bugs in the standard flags that cause + // transactions to pass as valid when they're actually invalid. For + // instance the STRICTENC flag was incorrectly allowing certain + // CHECKSIG NOT scripts to pass, even though they were invalid. + // + // There is a similar check in CreateNewBlock() to prevent creating + // invalid blocks (using TestBlockValidity), however allowing such + // transactions into the mempool can be exploited as a DoS attack. + unsigned int currentBlockScriptVerifyFlags{GetBlockScriptFlags(*m_active_chainstate.m_chain.Tip(), chainparams.GetConsensus())}; + if (!CheckInputsFromMempoolAndCache(tx, state, m_view, m_pool, currentBlockScriptVerifyFlags, + ws.m_precomputed_txdata, m_active_chainstate.CoinsTip())) { + LogPrintf("BUG! PLEASE REPORT THIS! CheckInputScripts failed against latest-block but not STANDARD flags %s, %s\n", hash.ToString(), state.ToString()); + return Assume(false); + } + + return true; +} + +bool MemPoolAccept::Finalize(const ATMPArgs& args, Workspace& ws) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + const CTransaction& tx = *ws.m_ptx; + const uint256& hash = ws.m_hash; + TxValidationState& state = ws.m_state; + const bool bypass_limits = args.m_bypass_limits; + + std::unique_ptr<CTxMemPoolEntry>& entry = ws.m_entry; + + // Remove conflicting transactions from the mempool + for (CTxMemPool::txiter it : ws.m_all_conflicting) + { + LogPrint(BCLog::MEMPOOL, "replacing tx %s with %s for %s additional fees, %d delta bytes\n", + it->GetTx().GetHash().ToString(), + hash.ToString(), + FormatMoney(ws.m_modified_fees - ws.m_conflicting_fees), + (int)entry->GetTxSize() - (int)ws.m_conflicting_size); + ws.m_replaced_transactions.push_back(it->GetSharedTx()); + } + m_pool.RemoveStaged(ws.m_all_conflicting, false, MemPoolRemovalReason::REPLACED); + + // This transaction should only count for fee estimation if: + // - it's not being re-added during a reorg which bypasses typical mempool fee limits + // - the node is not behind + // - the transaction is not dependent on any other transactions in the mempool + // - it's not part of a package. Since package relay is not currently supported, this + // transaction has not necessarily been accepted to miners' mempools. + bool validForFeeEstimation = !bypass_limits && !args.m_package_submission && IsCurrentForFeeEstimation(m_active_chainstate) && m_pool.HasNoInputsOf(tx); + + // Store transaction in memory + m_pool.addUnchecked(*entry, ws.m_ancestors, validForFeeEstimation); + + // trim mempool and check if tx was trimmed + // If we are validating a package, don't trim here because we could evict a previous transaction + // in the package. LimitMempoolSize() should be called at the very end to make sure the mempool + // is still within limits and package submission happens atomically. + if (!args.m_package_submission && !bypass_limits) { + LimitMempoolSize(m_pool, m_active_chainstate.CoinsTip(), gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, std::chrono::hours{gArgs.GetIntArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)}); + if (!m_pool.exists(GenTxid::Txid(hash))) + return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "mempool full"); + } + return true; +} + +bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>& workspaces, + PackageValidationState& package_state, + std::map<const uint256, const MempoolAcceptResult>& results) +{ + AssertLockHeld(cs_main); + AssertLockHeld(m_pool.cs); + // Sanity check: none of the transactions should be in the mempool, and none of the transactions + // should have a same-txid-different-witness equivalent in the mempool. + assert(std::all_of(workspaces.cbegin(), workspaces.cend(), [this](const auto& ws){ + return !m_pool.exists(GenTxid::Txid(ws.m_ptx->GetHash())); })); + + bool all_submitted = true; + // ConsensusScriptChecks adds to the script cache and is therefore consensus-critical; + // CheckInputsFromMempoolAndCache asserts that transactions only spend coins available from the + // mempool or UTXO set. Submit each transaction to the mempool immediately after calling + // ConsensusScriptChecks to make the outputs available for subsequent transactions. + for (Workspace& ws : workspaces) { + if (!ConsensusScriptChecks(args, ws)) { + results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); + // Since PolicyScriptChecks() passed, this should never fail. + Assume(false); + all_submitted = false; + package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR, + strprintf("BUG! PolicyScriptChecks succeeded but ConsensusScriptChecks failed: %s", + ws.m_ptx->GetHash().ToString())); + } + + // Re-calculate mempool ancestors to call addUnchecked(). They may have changed since the + // last calculation done in PreChecks, since package ancestors have already been submitted. + std::string unused_err_string; + if(!m_pool.CalculateMemPoolAncestors(*ws.m_entry, ws.m_ancestors, m_limit_ancestors, + m_limit_ancestor_size, m_limit_descendants, + m_limit_descendant_size, unused_err_string)) { + results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); + // Since PreChecks() and PackageMempoolChecks() both enforce limits, this should never fail. + Assume(false); + all_submitted = false; + package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR, + strprintf("BUG! Mempool ancestors or descendants were underestimated: %s", + ws.m_ptx->GetHash().ToString())); + } + // If we call LimitMempoolSize() for each individual Finalize(), the mempool will not take + // the transaction's descendant feerate into account because it hasn't seen them yet. Also, + // we risk evicting a transaction that a subsequent package transaction depends on. Instead, + // allow the mempool to temporarily bypass limits, the maximum package size) while + // submitting transactions individually and then trim at the very end. + if (!Finalize(args, ws)) { + results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); + // Since LimitMempoolSize() won't be called, this should never fail. + Assume(false); + all_submitted = false; + package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR, + strprintf("BUG! Adding to mempool failed: %s", ws.m_ptx->GetHash().ToString())); + } + } + + // It may or may not be the case that all the transactions made it into the mempool. Regardless, + // make sure we haven't exceeded max mempool size. + LimitMempoolSize(m_pool, m_active_chainstate.CoinsTip(), + gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, + std::chrono::hours{gArgs.GetIntArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)}); + + // Find the wtxids of the transactions that made it into the mempool. Allow partial submission, + // but don't report success unless they all made it into the mempool. + for (Workspace& ws : workspaces) { + if (m_pool.exists(GenTxid::Wtxid(ws.m_ptx->GetWitnessHash()))) { + results.emplace(ws.m_ptx->GetWitnessHash(), + MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees)); + GetMainSignals().TransactionAddedToMempool(ws.m_ptx, m_pool.GetAndIncrementSequence()); + } else { + all_submitted = false; + ws.m_state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "mempool full"); + results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); + } + } + return all_submitted; +} + +MempoolAcceptResult MemPoolAccept::AcceptSingleTransaction(const CTransactionRef& ptx, ATMPArgs& args) +{ + AssertLockHeld(cs_main); + LOCK(m_pool.cs); // mempool "read lock" (held through GetMainSignals().TransactionAddedToMempool()) + + Workspace ws(ptx); + + if (!PreChecks(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); + + if (m_rbf && !ReplacementChecks(ws)) return MempoolAcceptResult::Failure(ws.m_state); + + // Perform the inexpensive checks first and avoid hashing and signature verification unless + // those checks pass, to mitigate CPU exhaustion denial-of-service attacks. + if (!PolicyScriptChecks(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); + + if (!ConsensusScriptChecks(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); + + // Tx was accepted, but not added + if (args.m_test_accept) { + return MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees); + } + + if (!Finalize(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); + + GetMainSignals().TransactionAddedToMempool(ptx, m_pool.GetAndIncrementSequence()); + + return MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees); +} + +PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::vector<CTransactionRef>& txns, ATMPArgs& args) +{ + AssertLockHeld(cs_main); + + // These context-free package limits can be done before taking the mempool lock. + PackageValidationState package_state; + if (!CheckPackage(txns, package_state)) return PackageMempoolAcceptResult(package_state, {}); + + std::vector<Workspace> workspaces{}; + workspaces.reserve(txns.size()); + std::transform(txns.cbegin(), txns.cend(), std::back_inserter(workspaces), + [](const auto& tx) { return Workspace(tx); }); + std::map<const uint256, const MempoolAcceptResult> results; + + LOCK(m_pool.cs); + + // Do all PreChecks first and fail fast to avoid running expensive script checks when unnecessary. + for (Workspace& ws : workspaces) { + if (!PreChecks(args, ws)) { + package_state.Invalid(PackageValidationResult::PCKG_TX, "transaction failed"); + // Exit early to avoid doing pointless work. Update the failed tx result; the rest are unfinished. + results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); + return PackageMempoolAcceptResult(package_state, std::move(results)); + } + // Make the coins created by this transaction available for subsequent transactions in the + // package to spend. Since we already checked conflicts in the package and we don't allow + // replacements, we don't need to track the coins spent. Note that this logic will need to be + // updated if package replace-by-fee is allowed in the future. + assert(!args.m_allow_bip125_replacement); + m_viewmempool.PackageAddTransaction(ws.m_ptx); + } + + // Transactions must meet two minimum feerates: the mempool minimum fee and min relay fee. + // For transactions consisting of exactly one child and its parents, it suffices to use the + // package feerate (total modified fees / total virtual size) to check this requirement. + const auto m_total_vsize = std::accumulate(workspaces.cbegin(), workspaces.cend(), int64_t{0}, + [](int64_t sum, auto& ws) { return sum + ws.m_vsize; }); + const auto m_total_modified_fees = std::accumulate(workspaces.cbegin(), workspaces.cend(), CAmount{0}, + [](CAmount sum, auto& ws) { return sum + ws.m_modified_fees; }); + const CFeeRate package_feerate(m_total_modified_fees, m_total_vsize); + TxValidationState placeholder_state; + if (args.m_package_feerates && + !CheckFeeRate(m_total_vsize, m_total_modified_fees, placeholder_state)) { + package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-fee-too-low"); + return PackageMempoolAcceptResult(package_state, package_feerate, {}); + } + + // Apply package mempool ancestor/descendant limits. Skip if there is only one transaction, + // because it's unnecessary. Also, CPFP carve out can increase the limit for individual + // transactions, but this exemption is not extended to packages in CheckPackageLimits(). + std::string err_string; + if (txns.size() > 1 && !PackageMempoolChecks(txns, package_state)) { + return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); + } + + for (Workspace& ws : workspaces) { + if (!PolicyScriptChecks(args, ws)) { + // Exit early to avoid doing pointless work. Update the failed tx result; the rest are unfinished. + package_state.Invalid(PackageValidationResult::PCKG_TX, "transaction failed"); + results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); + return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); + } + if (args.m_test_accept) { + // When test_accept=true, transactions that pass PolicyScriptChecks are valid because there are + // no further mempool checks (passing PolicyScriptChecks implies passing ConsensusScriptChecks). + results.emplace(ws.m_ptx->GetWitnessHash(), + MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), + ws.m_vsize, ws.m_base_fees)); + } + } + + if (args.m_test_accept) return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); + + if (!SubmitPackage(args, workspaces, package_state, results)) { + // PackageValidationState filled in by SubmitPackage(). + return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); + } + + return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); +} + +PackageMempoolAcceptResult MemPoolAccept::AcceptPackage(const Package& package, ATMPArgs& args) +{ + AssertLockHeld(cs_main); + PackageValidationState package_state; + + // Check that the package is well-formed. If it isn't, we won't try to validate any of the + // transactions and thus won't return any MempoolAcceptResults, just a package-wide error. + + // Context-free package checks. + if (!CheckPackage(package, package_state)) return PackageMempoolAcceptResult(package_state, {}); + + // All transactions in the package must be a parent of the last transaction. This is just an + // opportunity for us to fail fast on a context-free check without taking the mempool lock. + if (!IsChildWithParents(package)) { + package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-child-with-parents"); + return PackageMempoolAcceptResult(package_state, {}); + } + + // IsChildWithParents() guarantees the package is > 1 transactions. + assert(package.size() > 1); + // The package must be 1 child with all of its unconfirmed parents. The package is expected to + // be sorted, so the last transaction is the child. + const auto& child = package.back(); + std::unordered_set<uint256, SaltedTxidHasher> unconfirmed_parent_txids; + std::transform(package.cbegin(), package.cend() - 1, + std::inserter(unconfirmed_parent_txids, unconfirmed_parent_txids.end()), + [](const auto& tx) { return tx->GetHash(); }); + + // All child inputs must refer to a preceding package transaction or a confirmed UTXO. The only + // way to verify this is to look up the child's inputs in our current coins view (not including + // mempool), and enforce that all parents not present in the package be available at chain tip. + // Since this check can bring new coins into the coins cache, keep track of these coins and + // uncache them if we don't end up submitting this package to the mempool. + const CCoinsViewCache& coins_tip_cache = m_active_chainstate.CoinsTip(); + for (const auto& input : child->vin) { + if (!coins_tip_cache.HaveCoinInCache(input.prevout)) { + args.m_coins_to_uncache.push_back(input.prevout); + } + } + // Using the MemPoolAccept m_view cache allows us to look up these same coins faster later. + // This should be connecting directly to CoinsTip, not to m_viewmempool, because we specifically + // require inputs to be confirmed if they aren't in the package. + m_view.SetBackend(m_active_chainstate.CoinsTip()); + const auto package_or_confirmed = [this, &unconfirmed_parent_txids](const auto& input) { + return unconfirmed_parent_txids.count(input.prevout.hash) > 0 || m_view.HaveCoin(input.prevout); + }; + if (!std::all_of(child->vin.cbegin(), child->vin.cend(), package_or_confirmed)) { + package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-child-with-unconfirmed-parents"); + return PackageMempoolAcceptResult(package_state, {}); + } + // Protect against bugs where we pull more inputs from disk that miss being added to + // coins_to_uncache. The backend will be connected again when needed in PreChecks. + m_view.SetBackend(m_dummy); + + LOCK(m_pool.cs); + std::map<const uint256, const MempoolAcceptResult> results; + // Node operators are free to set their mempool policies however they please, nodes may receive + // transactions in different orders, and malicious counterparties may try to take advantage of + // policy differences to pin or delay propagation of transactions. As such, it's possible for + // some package transaction(s) to already be in the mempool, and we don't want to reject the + // entire package in that case (as that could be a censorship vector). De-duplicate the + // transactions that are already in the mempool, and only call AcceptMultipleTransactions() with + // the new transactions. This ensures we don't double-count transaction counts and sizes when + // checking ancestor/descendant limits, or double-count transaction fees for fee-related policy. + ATMPArgs single_args = ATMPArgs::SingleInPackageAccept(args); + bool quit_early{false}; + std::vector<CTransactionRef> txns_new; + for (const auto& tx : package) { + const auto& wtxid = tx->GetWitnessHash(); + const auto& txid = tx->GetHash(); + // There are 3 possibilities: already in mempool, same-txid-diff-wtxid already in mempool, + // or not in mempool. An already confirmed tx is treated as one not in mempool, because all + // we know is that the inputs aren't available. + if (m_pool.exists(GenTxid::Wtxid(wtxid))) { + // Exact transaction already exists in the mempool. + auto iter = m_pool.GetIter(txid); + assert(iter != std::nullopt); + results.emplace(wtxid, MempoolAcceptResult::MempoolTx(iter.value()->GetTxSize(), iter.value()->GetFee())); + } else if (m_pool.exists(GenTxid::Txid(txid))) { + // Transaction with the same non-witness data but different witness (same txid, + // different wtxid) already exists in the mempool. + // + // We don't allow replacement transactions right now, so just swap the package + // transaction for the mempool one. Note that we are ignoring the validity of the + // package transaction passed in. + // TODO: allow witness replacement in packages. + auto iter = m_pool.GetIter(txid); + assert(iter != std::nullopt); + // Provide the wtxid of the mempool tx so that the caller can look it up in the mempool. + results.emplace(wtxid, MempoolAcceptResult::MempoolTxDifferentWitness(iter.value()->GetTx().GetWitnessHash())); + } else { + // Transaction does not already exist in the mempool. + // Try submitting the transaction on its own. + const auto single_res = AcceptSingleTransaction(tx, single_args); + if (single_res.m_result_type == MempoolAcceptResult::ResultType::VALID) { + // The transaction succeeded on its own and is now in the mempool. Don't include it + // in package validation, because its fees should only be "used" once. + assert(m_pool.exists(GenTxid::Wtxid(wtxid))); + results.emplace(wtxid, single_res); + } else if (single_res.m_state.GetResult() != TxValidationResult::TX_MEMPOOL_POLICY && + single_res.m_state.GetResult() != TxValidationResult::TX_MISSING_INPUTS) { + // Package validation policy only differs from individual policy in its evaluation + // of feerate. For example, if a transaction fails here due to violation of a + // consensus rule, the result will not change when it is submitted as part of a + // package. To minimize the amount of repeated work, unless the transaction fails + // due to feerate or missing inputs (its parent is a previous transaction in the + // package that failed due to feerate), don't run package validation. Note that this + // decision might not make sense if different types of packages are allowed in the + // future. Continue individually validating the rest of the transactions, because + // some of them may still be valid. + quit_early = true; + } else { + txns_new.push_back(tx); + } + } + } + + // Nothing to do if the entire package has already been submitted. + if (quit_early || txns_new.empty()) { + // No package feerate when no package validation was done. + return PackageMempoolAcceptResult(package_state, std::move(results)); + } + // Validate the (deduplicated) transactions as a package. + auto submission_result = AcceptMultipleTransactions(txns_new, args); + // Include already-in-mempool transaction results in the final result. + for (const auto& [wtxid, mempoolaccept_res] : results) { + submission_result.m_tx_results.emplace(wtxid, mempoolaccept_res); + } + if (submission_result.m_state.IsValid()) assert(submission_result.m_package_feerate.has_value()); + return submission_result; +} + +} // anon namespace + +MempoolAcceptResult AcceptToMemoryPool(CChainState& active_chainstate, const CTransactionRef& tx, + int64_t accept_time, bool bypass_limits, bool test_accept) + EXCLUSIVE_LOCKS_REQUIRED(::cs_main) +{ + AssertLockHeld(::cs_main); + const CChainParams& chainparams{active_chainstate.m_params}; + assert(active_chainstate.GetMempool() != nullptr); + CTxMemPool& pool{*active_chainstate.GetMempool()}; + + std::vector<COutPoint> coins_to_uncache; + auto args = MemPoolAccept::ATMPArgs::SingleAccept(chainparams, accept_time, bypass_limits, coins_to_uncache, test_accept); + const MempoolAcceptResult result = MemPoolAccept(pool, active_chainstate).AcceptSingleTransaction(tx, args); + if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) { + // Remove coins that were not present in the coins cache before calling + // AcceptSingleTransaction(); this is to prevent memory DoS in case we receive a large + // number of invalid transactions that attempt to overrun the in-memory coins cache + // (`CCoinsViewCache::cacheCoins`). + + for (const COutPoint& hashTx : coins_to_uncache) + active_chainstate.CoinsTip().Uncache(hashTx); + } + // After we've (potentially) uncached entries, ensure our coins cache is still within its size limits + BlockValidationState state_dummy; + active_chainstate.FlushStateToDisk(state_dummy, FlushStateMode::PERIODIC); + return result; +} + +PackageMempoolAcceptResult ProcessNewPackage(CChainState& active_chainstate, CTxMemPool& pool, + const Package& package, bool test_accept) +{ + AssertLockHeld(cs_main); + assert(!package.empty()); + assert(std::all_of(package.cbegin(), package.cend(), [](const auto& tx){return tx != nullptr;})); + + std::vector<COutPoint> coins_to_uncache; + const CChainParams& chainparams = Params(); + const auto result = [&]() EXCLUSIVE_LOCKS_REQUIRED(cs_main) { + AssertLockHeld(cs_main); + if (test_accept) { + auto args = MemPoolAccept::ATMPArgs::PackageTestAccept(chainparams, GetTime(), coins_to_uncache); + return MemPoolAccept(pool, active_chainstate).AcceptMultipleTransactions(package, args); + } else { + auto args = MemPoolAccept::ATMPArgs::PackageChildWithParents(chainparams, GetTime(), coins_to_uncache); + return MemPoolAccept(pool, active_chainstate).AcceptPackage(package, args); + } + }(); + + // Uncache coins pertaining to transactions that were not submitted to the mempool. + if (test_accept || result.m_state.IsInvalid()) { + for (const COutPoint& hashTx : coins_to_uncache) { + active_chainstate.CoinsTip().Uncache(hashTx); + } + } + // Ensure the coins cache is still within limits. + BlockValidationState state_dummy; + active_chainstate.FlushStateToDisk(state_dummy, FlushStateMode::PERIODIC); + return result; +} + +CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams) +{ + int halvings = nHeight / consensusParams.nSubsidyHalvingInterval; + // Force block reward to zero when right shift is undefined. + if (halvings >= 64) + return 0; + + CAmount nSubsidy = 50 * COIN; + // Subsidy is cut in half every 210,000 blocks which will occur approximately every 4 years. + nSubsidy >>= halvings; + return nSubsidy; +} + +CoinsViews::CoinsViews( + fs::path ldb_name, + size_t cache_size_bytes, + bool in_memory, + bool should_wipe) : m_dbview( + gArgs.GetDataDirNet() / ldb_name, cache_size_bytes, in_memory, should_wipe), + m_catcherview(&m_dbview) {} + +void CoinsViews::InitCache() +{ + AssertLockHeld(::cs_main); + m_cacheview = std::make_unique<CCoinsViewCache>(&m_catcherview); +} + +CChainState::CChainState( + CTxMemPool* mempool, + BlockManager& blockman, + ChainstateManager& chainman, + std::optional<uint256> from_snapshot_blockhash) + : m_mempool(mempool), + m_blockman(blockman), + m_params(::Params()), + m_chainman(chainman), + m_from_snapshot_blockhash(from_snapshot_blockhash) {} + +void CChainState::InitCoinsDB( + size_t cache_size_bytes, + bool in_memory, + bool should_wipe, + fs::path leveldb_name) +{ + if (m_from_snapshot_blockhash) { + leveldb_name += "_" + m_from_snapshot_blockhash->ToString(); + } + + m_coins_views = std::make_unique<CoinsViews>( + leveldb_name, cache_size_bytes, in_memory, should_wipe); +} + +void CChainState::InitCoinsCache(size_t cache_size_bytes) +{ + AssertLockHeld(::cs_main); + assert(m_coins_views != nullptr); + m_coinstip_cache_size_bytes = cache_size_bytes; + m_coins_views->InitCache(); +} + +// Note that though this is marked const, we may end up modifying `m_cached_finished_ibd`, which +// is a performance-related implementation detail. This function must be marked +// `const` so that `CValidationInterface` clients (which are given a `const CChainState*`) +// can call it. +// +bool CChainState::IsInitialBlockDownload() const +{ + // Optimization: pre-test latch before taking the lock. + if (m_cached_finished_ibd.load(std::memory_order_relaxed)) + return false; + + LOCK(cs_main); + if (m_cached_finished_ibd.load(std::memory_order_relaxed)) + return false; + if (fImporting || fReindex) + return true; + if (m_chain.Tip() == nullptr) + return true; + if (m_chain.Tip()->nChainWork < nMinimumChainWork) + return true; + if (m_chain.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge)) + return true; + LogPrintf("Leaving InitialBlockDownload (latching to false)\n"); + m_cached_finished_ibd.store(true, std::memory_order_relaxed); + return false; +} + +static void AlertNotify(const std::string& strMessage) +{ + uiInterface.NotifyAlertChanged(); +#if HAVE_SYSTEM + std::string strCmd = gArgs.GetArg("-alertnotify", ""); + if (strCmd.empty()) return; + + // Alert text should be plain ascii coming from a trusted source, but to + // be safe we first strip anything not in safeChars, then add single quotes around + // the whole string before passing it to the shell: + std::string singleQuote("'"); + std::string safeStatus = SanitizeString(strMessage); + safeStatus = singleQuote+safeStatus+singleQuote; + ReplaceAll(strCmd, "%s", safeStatus); + + std::thread t(runCommand, strCmd); + t.detach(); // thread runs free +#endif +} + +void CChainState::CheckForkWarningConditions() +{ + AssertLockHeld(cs_main); + + // Before we get past initial download, we cannot reliably alert about forks + // (we assume we don't get stuck on a fork before finishing our initial sync) + if (IsInitialBlockDownload()) { + return; + } + + if (m_chainman.m_best_invalid && m_chainman.m_best_invalid->nChainWork > m_chain.Tip()->nChainWork + (GetBlockProof(*m_chain.Tip()) * 6)) { + LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n", __func__); + SetfLargeWorkInvalidChainFound(true); + } else { + SetfLargeWorkInvalidChainFound(false); + } +} + +// Called both upon regular invalid block discovery *and* InvalidateBlock +void CChainState::InvalidChainFound(CBlockIndex* pindexNew) +{ + AssertLockHeld(cs_main); + if (!m_chainman.m_best_invalid || pindexNew->nChainWork > m_chainman.m_best_invalid->nChainWork) { + m_chainman.m_best_invalid = pindexNew; + } + if (m_chainman.m_best_header != nullptr && m_chainman.m_best_header->GetAncestor(pindexNew->nHeight) == pindexNew) { + m_chainman.m_best_header = m_chain.Tip(); + } + + LogPrintf("%s: invalid block=%s height=%d log2_work=%f date=%s\n", __func__, + pindexNew->GetBlockHash().ToString(), pindexNew->nHeight, + log(pindexNew->nChainWork.getdouble())/log(2.0), FormatISO8601DateTime(pindexNew->GetBlockTime())); + CBlockIndex *tip = m_chain.Tip(); + assert (tip); + LogPrintf("%s: current best=%s height=%d log2_work=%f date=%s\n", __func__, + tip->GetBlockHash().ToString(), m_chain.Height(), log(tip->nChainWork.getdouble())/log(2.0), + FormatISO8601DateTime(tip->GetBlockTime())); + CheckForkWarningConditions(); +} + +// Same as InvalidChainFound, above, except not called directly from InvalidateBlock, +// which does its own setBlockIndexCandidates management. +void CChainState::InvalidBlockFound(CBlockIndex* pindex, const BlockValidationState& state) +{ + AssertLockHeld(cs_main); + if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) { + pindex->nStatus |= BLOCK_FAILED_VALID; + m_chainman.m_failed_blocks.insert(pindex); + m_blockman.m_dirty_blockindex.insert(pindex); + setBlockIndexCandidates.erase(pindex); + InvalidChainFound(pindex); + } +} + +void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txundo, int nHeight) +{ + // mark inputs spent + if (!tx.IsCoinBase()) { + txundo.vprevout.reserve(tx.vin.size()); + for (const CTxIn &txin : tx.vin) { + txundo.vprevout.emplace_back(); + bool is_spent = inputs.SpendCoin(txin.prevout, &txundo.vprevout.back()); + assert(is_spent); + } + } + // add outputs + AddCoins(inputs, tx, nHeight); +} + +bool CScriptCheck::operator()() { + const CScript &scriptSig = ptxTo->vin[nIn].scriptSig; + const CScriptWitness *witness = &ptxTo->vin[nIn].scriptWitness; + return VerifyScript(scriptSig, m_tx_out.scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, m_tx_out.nValue, cacheStore, *txdata), &error); +} + +static CuckooCache::cache<uint256, SignatureCacheHasher> g_scriptExecutionCache; +static CSHA256 g_scriptExecutionCacheHasher; + +void InitScriptExecutionCache() { + // Setup the salted hasher + uint256 nonce = GetRandHash(); + // We want the nonce to be 64 bytes long to force the hasher to process + // this chunk, which makes later hash computations more efficient. We + // just write our 32-byte entropy twice to fill the 64 bytes. + g_scriptExecutionCacheHasher.Write(nonce.begin(), 32); + g_scriptExecutionCacheHasher.Write(nonce.begin(), 32); + // nMaxCacheSize is unsigned. If -maxsigcachesize is set to zero, + // setup_bytes creates the minimum possible cache (2 elements). + size_t nMaxCacheSize = std::min(std::max((int64_t)0, gArgs.GetIntArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) / 2), MAX_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20); + size_t nElems = g_scriptExecutionCache.setup_bytes(nMaxCacheSize); + LogPrintf("Using %zu MiB out of %zu/2 requested for script execution cache, able to store %zu elements\n", + (nElems*sizeof(uint256)) >>20, (nMaxCacheSize*2)>>20, nElems); +} + +/** + * Check whether all of this transaction's input scripts succeed. + * + * This involves ECDSA signature checks so can be computationally intensive. This function should + * only be called after the cheap sanity checks in CheckTxInputs passed. + * + * If pvChecks is not nullptr, script checks are pushed onto it instead of being performed inline. Any + * script checks which are not necessary (eg due to script execution cache hits) are, obviously, + * not pushed onto pvChecks/run. + * + * Setting cacheSigStore/cacheFullScriptStore to false will remove elements from the corresponding cache + * which are matched. This is useful for checking blocks where we will likely never need the cache + * entry again. + * + * Note that we may set state.reason to NOT_STANDARD for extra soft-fork flags in flags, block-checking + * callers should probably reset it to CONSENSUS in such cases. + * + * Non-static (and re-declared) in src/test/txvalidationcache_tests.cpp + */ +bool CheckInputScripts(const CTransaction& tx, TxValidationState& state, + const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore, + bool cacheFullScriptStore, PrecomputedTransactionData& txdata, + std::vector<CScriptCheck>* pvChecks) +{ + if (tx.IsCoinBase()) return true; + + if (pvChecks) { + pvChecks->reserve(tx.vin.size()); + } + + // First check if script executions have been cached with the same + // flags. Note that this assumes that the inputs provided are + // correct (ie that the transaction hash which is in tx's prevouts + // properly commits to the scriptPubKey in the inputs view of that + // transaction). + uint256 hashCacheEntry; + CSHA256 hasher = g_scriptExecutionCacheHasher; + hasher.Write(tx.GetWitnessHash().begin(), 32).Write((unsigned char*)&flags, sizeof(flags)).Finalize(hashCacheEntry.begin()); + AssertLockHeld(cs_main); //TODO: Remove this requirement by making CuckooCache not require external locks + if (g_scriptExecutionCache.contains(hashCacheEntry, !cacheFullScriptStore)) { + return true; + } + + if (!txdata.m_spent_outputs_ready) { + std::vector<CTxOut> spent_outputs; + spent_outputs.reserve(tx.vin.size()); + + for (const auto& txin : tx.vin) { + const COutPoint& prevout = txin.prevout; + const Coin& coin = inputs.AccessCoin(prevout); + assert(!coin.IsSpent()); + spent_outputs.emplace_back(coin.out); + } + txdata.Init(tx, std::move(spent_outputs)); + } + assert(txdata.m_spent_outputs.size() == tx.vin.size()); + + for (unsigned int i = 0; i < tx.vin.size(); i++) { + + // We very carefully only pass in things to CScriptCheck which + // are clearly committed to by tx' witness hash. This provides + // a sanity check that our caching is not introducing consensus + // failures through additional data in, eg, the coins being + // spent being checked as a part of CScriptCheck. + + // Verify signature + CScriptCheck check(txdata.m_spent_outputs[i], tx, i, flags, cacheSigStore, &txdata); + if (pvChecks) { + pvChecks->push_back(CScriptCheck()); + check.swap(pvChecks->back()); + } else if (!check()) { + if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) { + // Check whether the failure was caused by a + // non-mandatory script verification check, such as + // non-standard DER encodings or non-null dummy + // arguments; if so, ensure we return NOT_STANDARD + // instead of CONSENSUS to avoid downstream users + // splitting the network between upgraded and + // non-upgraded nodes by banning CONSENSUS-failing + // data providers. + CScriptCheck check2(txdata.m_spent_outputs[i], tx, i, + flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheSigStore, &txdata); + if (check2()) + return state.Invalid(TxValidationResult::TX_NOT_STANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError()))); + } + // MANDATORY flag failures correspond to + // TxValidationResult::TX_CONSENSUS. Because CONSENSUS + // failures are the most serious case of validation + // failures, we may need to consider using + // RECENT_CONSENSUS_CHANGE for any script failure that + // could be due to non-upgraded nodes which we may want to + // support, to avoid splitting the network (but this + // depends on the details of how net_processing handles + // such errors). + return state.Invalid(TxValidationResult::TX_CONSENSUS, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError()))); + } + } + + if (cacheFullScriptStore && !pvChecks) { + // We executed all of the provided scripts, and were told to + // cache the result. Do so now. + g_scriptExecutionCache.insert(hashCacheEntry); + } + + return true; +} + +bool AbortNode(BlockValidationState& state, const std::string& strMessage, const bilingual_str& userMessage) +{ + AbortNode(strMessage, userMessage); + return state.Error(strMessage); +} + +/** + * Restore the UTXO in a Coin at a given COutPoint + * @param undo The Coin to be restored. + * @param view The coins view to which to apply the changes. + * @param out The out point that corresponds to the tx input. + * @return A DisconnectResult as an int + */ +int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out) +{ + bool fClean = true; + + if (view.HaveCoin(out)) fClean = false; // overwriting transaction output + + if (undo.nHeight == 0) { + // Missing undo metadata (height and coinbase). Older versions included this + // information only in undo records for the last spend of a transactions' + // outputs. This implies that it must be present for some other output of the same tx. + const Coin& alternate = AccessByTxid(view, out.hash); + if (!alternate.IsSpent()) { + undo.nHeight = alternate.nHeight; + undo.fCoinBase = alternate.fCoinBase; + } else { + return DISCONNECT_FAILED; // adding output for transaction without known metadata + } + } + // If the coin already exists as an unspent coin in the cache, then the + // possible_overwrite parameter to AddCoin must be set to true. We have + // already checked whether an unspent coin exists above using HaveCoin, so + // we don't need to guess. When fClean is false, an unspent coin already + // existed and it is an overwrite. + view.AddCoin(out, std::move(undo), !fClean); + + return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN; +} + +/** Undo the effects of this block (with given index) on the UTXO set represented by coins. + * When FAILED is returned, view is left in an indeterminate state. */ +DisconnectResult CChainState::DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view) +{ + AssertLockHeld(::cs_main); + bool fClean = true; + + CBlockUndo blockUndo; + if (!UndoReadFromDisk(blockUndo, pindex)) { + error("DisconnectBlock(): failure reading undo data"); + return DISCONNECT_FAILED; + } + + if (blockUndo.vtxundo.size() + 1 != block.vtx.size()) { + error("DisconnectBlock(): block and undo data inconsistent"); + return DISCONNECT_FAILED; + } + + // undo transactions in reverse order + for (int i = block.vtx.size() - 1; i >= 0; i--) { + const CTransaction &tx = *(block.vtx[i]); + uint256 hash = tx.GetHash(); + bool is_coinbase = tx.IsCoinBase(); + + // Check that all outputs are available and match the outputs in the block itself + // exactly. + for (size_t o = 0; o < tx.vout.size(); o++) { + if (!tx.vout[o].scriptPubKey.IsUnspendable()) { + COutPoint out(hash, o); + Coin coin; + bool is_spent = view.SpendCoin(out, &coin); + if (!is_spent || tx.vout[o] != coin.out || pindex->nHeight != coin.nHeight || is_coinbase != coin.fCoinBase) { + fClean = false; // transaction output mismatch + } + } + } + + // restore inputs + if (i > 0) { // not coinbases + CTxUndo &txundo = blockUndo.vtxundo[i-1]; + if (txundo.vprevout.size() != tx.vin.size()) { + error("DisconnectBlock(): transaction and undo data inconsistent"); + return DISCONNECT_FAILED; + } + for (unsigned int j = tx.vin.size(); j > 0;) { + --j; + const COutPoint& out = tx.vin[j].prevout; + int res = ApplyTxInUndo(std::move(txundo.vprevout[j]), view, out); + if (res == DISCONNECT_FAILED) return DISCONNECT_FAILED; + fClean = fClean && res != DISCONNECT_UNCLEAN; + } + // At this point, all of txundo.vprevout should have been moved out. + } + } + + // move best block pointer to prevout block + view.SetBestBlock(pindex->pprev->GetBlockHash()); + + return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN; +} + +static CCheckQueue<CScriptCheck> scriptcheckqueue(128); + +void StartScriptCheckWorkerThreads(int threads_num) +{ + scriptcheckqueue.StartWorkerThreads(threads_num); +} + +void StopScriptCheckWorkerThreads() +{ + scriptcheckqueue.StopWorkerThreads(); +} + +/** + * Threshold condition checker that triggers when unknown versionbits are seen on the network. + */ +class WarningBitsConditionChecker : public AbstractThresholdConditionChecker +{ +private: + int bit; + +public: + explicit WarningBitsConditionChecker(int bitIn) : bit(bitIn) {} + + int64_t BeginTime(const Consensus::Params& params) const override { return 0; } + int64_t EndTime(const Consensus::Params& params) const override { return std::numeric_limits<int64_t>::max(); } + int Period(const Consensus::Params& params) const override { return params.nMinerConfirmationWindow; } + int Threshold(const Consensus::Params& params) const override { return params.nRuleChangeActivationThreshold; } + + bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const override + { + return pindex->nHeight >= params.MinBIP9WarningHeight && + ((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) && + ((pindex->nVersion >> bit) & 1) != 0 && + ((g_versionbitscache.ComputeBlockVersion(pindex->pprev, params) >> bit) & 1) == 0; + } +}; + +static std::array<ThresholdConditionCache, VERSIONBITS_NUM_BITS> warningcache GUARDED_BY(cs_main); + +static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const Consensus::Params& consensusparams) +{ + // BIP16 didn't become active until Apr 1 2012 (on mainnet, and + // retroactively applied to testnet) + // However, only one historical block violated the P2SH rules (on both + // mainnet and testnet). + // Similarly, only one historical block violated the TAPROOT rules on + // mainnet. + // For simplicity, always leave P2SH+WITNESS+TAPROOT on except for the two + // violating blocks. + uint32_t flags{SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_TAPROOT}; + const auto it{consensusparams.script_flag_exceptions.find(*Assert(block_index.phashBlock))}; + if (it != consensusparams.script_flag_exceptions.end()) { + flags = it->second; + } + + // Enforce the DERSIG (BIP66) rule + if (DeploymentActiveAt(block_index, consensusparams, Consensus::DEPLOYMENT_DERSIG)) { + flags |= SCRIPT_VERIFY_DERSIG; + } + + // Enforce CHECKLOCKTIMEVERIFY (BIP65) + if (DeploymentActiveAt(block_index, consensusparams, Consensus::DEPLOYMENT_CLTV)) { + flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY; + } + + // Enforce CHECKSEQUENCEVERIFY (BIP112) + if (DeploymentActiveAt(block_index, consensusparams, Consensus::DEPLOYMENT_CSV)) { + flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY; + } + + // Enforce BIP147 NULLDUMMY (activated simultaneously with segwit) + if (DeploymentActiveAt(block_index, consensusparams, Consensus::DEPLOYMENT_SEGWIT)) { + flags |= SCRIPT_VERIFY_NULLDUMMY; + } + + return flags; +} + + +static int64_t nTimeCheck = 0; +static int64_t nTimeForks = 0; +static int64_t nTimeConnect = 0; +static int64_t nTimeVerify = 0; +static int64_t nTimeUndo = 0; +static int64_t nTimeIndex = 0; +static int64_t nTimeTotal = 0; +static int64_t nBlocksTotal = 0; + +/** Apply the effects of this block (with given index) on the UTXO set represented by coins. + * Validity checks that depend on the UTXO set are also done; ConnectBlock() + * can fail if those validity checks fail (among other reasons). */ +bool CChainState::ConnectBlock(const CBlock& block, BlockValidationState& state, CBlockIndex* pindex, + CCoinsViewCache& view, bool fJustCheck) +{ + AssertLockHeld(cs_main); + assert(pindex); + + uint256 block_hash{block.GetHash()}; + assert(*pindex->phashBlock == block_hash); + + int64_t nTimeStart = GetTimeMicros(); + + // Check it again in case a previous version let a bad block in + // NOTE: We don't currently (re-)invoke ContextualCheckBlock() or + // ContextualCheckBlockHeader() here. This means that if we add a new + // consensus rule that is enforced in one of those two functions, then we + // may have let in a block that violates the rule prior to updating the + // software, and we would NOT be enforcing the rule here. Fully solving + // upgrade from one software version to the next after a consensus rule + // change is potentially tricky and issue-specific (see NeedsRedownload() + // for one approach that was used for BIP 141 deployment). + // Also, currently the rule against blocks more than 2 hours in the future + // is enforced in ContextualCheckBlockHeader(); we wouldn't want to + // re-enforce that rule here (at least until we make it impossible for + // GetAdjustedTime() to go backward). + if (!CheckBlock(block, state, m_params.GetConsensus(), !fJustCheck, !fJustCheck)) { + if (state.GetResult() == BlockValidationResult::BLOCK_MUTATED) { + // We don't write down blocks to disk if they may have been + // corrupted, so this should be impossible unless we're having hardware + // problems. + return AbortNode(state, "Corrupt block found indicating potential hardware failure; shutting down"); + } + return error("%s: Consensus::CheckBlock: %s", __func__, state.ToString()); + } + + // verify that the view's current state corresponds to the previous block + uint256 hashPrevBlock = pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash(); + assert(hashPrevBlock == view.GetBestBlock()); + + nBlocksTotal++; + + // Special case for the genesis block, skipping connection of its transactions + // (its coinbase is unspendable) + if (block_hash == m_params.GetConsensus().hashGenesisBlock) { + if (!fJustCheck) + view.SetBestBlock(pindex->GetBlockHash()); + return true; + } + + bool fScriptChecks = true; + if (!hashAssumeValid.IsNull()) { + // We've been configured with the hash of a block which has been externally verified to have a valid history. + // A suitable default value is included with the software and updated from time to time. Because validity + // relative to a piece of software is an objective fact these defaults can be easily reviewed. + // This setting doesn't force the selection of any particular chain but makes validating some faster by + // effectively caching the result of part of the verification. + BlockMap::const_iterator it = m_blockman.m_block_index.find(hashAssumeValid); + if (it != m_blockman.m_block_index.end()) { + if (it->second.GetAncestor(pindex->nHeight) == pindex && + m_chainman.m_best_header->GetAncestor(pindex->nHeight) == pindex && + m_chainman.m_best_header->nChainWork >= nMinimumChainWork) { + // This block is a member of the assumed verified chain and an ancestor of the best header. + // Script verification is skipped when connecting blocks under the + // assumevalid block. Assuming the assumevalid block is valid this + // is safe because block merkle hashes are still computed and checked, + // Of course, if an assumed valid block is invalid due to false scriptSigs + // this optimization would allow an invalid chain to be accepted. + // The equivalent time check discourages hash power from extorting the network via DOS attack + // into accepting an invalid block through telling users they must manually set assumevalid. + // Requiring a software change or burying the invalid block, regardless of the setting, makes + // it hard to hide the implication of the demand. This also avoids having release candidates + // that are hardly doing any signature verification at all in testing without having to + // artificially set the default assumed verified block further back. + // The test against nMinimumChainWork prevents the skipping when denied access to any chain at + // least as good as the expected chain. + fScriptChecks = (GetBlockProofEquivalentTime(*m_chainman.m_best_header, *pindex, *m_chainman.m_best_header, m_params.GetConsensus()) <= 60 * 60 * 24 * 7 * 2); + } + } + } + + int64_t nTime1 = GetTimeMicros(); nTimeCheck += nTime1 - nTimeStart; + LogPrint(BCLog::BENCH, " - Sanity checks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime1 - nTimeStart), nTimeCheck * MICRO, nTimeCheck * MILLI / nBlocksTotal); + + // Do not allow blocks that contain transactions which 'overwrite' older transactions, + // unless those are already completely spent. + // If such overwrites are allowed, coinbases and transactions depending upon those + // can be duplicated to remove the ability to spend the first instance -- even after + // being sent to another address. + // See BIP30, CVE-2012-1909, and http://r6.ca/blog/20120206T005236Z.html for more information. + // This rule was originally applied to all blocks with a timestamp after March 15, 2012, 0:00 UTC. + // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the + // two in the chain that violate it. This prevents exploiting the issue against nodes during their + // initial block download. + bool fEnforceBIP30 = !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256S("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) || + (pindex->nHeight==91880 && pindex->GetBlockHash() == uint256S("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721"))); + + // Once BIP34 activated it was not possible to create new duplicate coinbases and thus other than starting + // with the 2 existing duplicate coinbase pairs, not possible to create overwriting txs. But by the + // time BIP34 activated, in each of the existing pairs the duplicate coinbase had overwritten the first + // before the first had been spent. Since those coinbases are sufficiently buried it's no longer possible to create further + // duplicate transactions descending from the known pairs either. + // If we're on the known chain at height greater than where BIP34 activated, we can save the db accesses needed for the BIP30 check. + + // BIP34 requires that a block at height X (block X) has its coinbase + // scriptSig start with a CScriptNum of X (indicated height X). The above + // logic of no longer requiring BIP30 once BIP34 activates is flawed in the + // case that there is a block X before the BIP34 height of 227,931 which has + // an indicated height Y where Y is greater than X. The coinbase for block + // X would also be a valid coinbase for block Y, which could be a BIP30 + // violation. An exhaustive search of all mainnet coinbases before the + // BIP34 height which have an indicated height greater than the block height + // reveals many occurrences. The 3 lowest indicated heights found are + // 209,921, 490,897, and 1,983,702 and thus coinbases for blocks at these 3 + // heights would be the first opportunity for BIP30 to be violated. + + // The search reveals a great many blocks which have an indicated height + // greater than 1,983,702, so we simply remove the optimization to skip + // BIP30 checking for blocks at height 1,983,702 or higher. Before we reach + // that block in another 25 years or so, we should take advantage of a + // future consensus change to do a new and improved version of BIP34 that + // will actually prevent ever creating any duplicate coinbases in the + // future. + static constexpr int BIP34_IMPLIES_BIP30_LIMIT = 1983702; + + // There is no potential to create a duplicate coinbase at block 209,921 + // because this is still before the BIP34 height and so explicit BIP30 + // checking is still active. + + // The final case is block 176,684 which has an indicated height of + // 490,897. Unfortunately, this issue was not discovered until about 2 weeks + // before block 490,897 so there was not much opportunity to address this + // case other than to carefully analyze it and determine it would not be a + // problem. Block 490,897 was, in fact, mined with a different coinbase than + // block 176,684, but it is important to note that even if it hadn't been or + // is remined on an alternate fork with a duplicate coinbase, we would still + // not run into a BIP30 violation. This is because the coinbase for 176,684 + // is spent in block 185,956 in transaction + // d4f7fbbf92f4a3014a230b2dc70b8058d02eb36ac06b4a0736d9d60eaa9e8781. This + // spending transaction can't be duplicated because it also spends coinbase + // 0328dd85c331237f18e781d692c92de57649529bd5edf1d01036daea32ffde29. This + // coinbase has an indicated height of over 4.2 billion, and wouldn't be + // duplicatable until that height, and it's currently impossible to create a + // chain that long. Nevertheless we may wish to consider a future soft fork + // which retroactively prevents block 490,897 from creating a duplicate + // coinbase. The two historical BIP30 violations often provide a confusing + // edge case when manipulating the UTXO and it would be simpler not to have + // another edge case to deal with. + + // testnet3 has no blocks before the BIP34 height with indicated heights + // post BIP34 before approximately height 486,000,000. After block + // 1,983,702 testnet3 starts doing unnecessary BIP30 checking again. + assert(pindex->pprev); + CBlockIndex* pindexBIP34height = pindex->pprev->GetAncestor(m_params.GetConsensus().BIP34Height); + //Only continue to enforce if we're below BIP34 activation height or the block hash at that height doesn't correspond. + fEnforceBIP30 = fEnforceBIP30 && (!pindexBIP34height || !(pindexBIP34height->GetBlockHash() == m_params.GetConsensus().BIP34Hash)); + + // TODO: Remove BIP30 checking from block height 1,983,702 on, once we have a + // consensus change that ensures coinbases at those heights cannot + // duplicate earlier coinbases. + if (fEnforceBIP30 || pindex->nHeight >= BIP34_IMPLIES_BIP30_LIMIT) { + for (const auto& tx : block.vtx) { + for (size_t o = 0; o < tx->vout.size(); o++) { + if (view.HaveCoin(COutPoint(tx->GetHash(), o))) { + LogPrintf("ERROR: ConnectBlock(): tried to overwrite transaction\n"); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-BIP30"); + } + } + } + } + + // Enforce BIP68 (sequence locks) + int nLockTimeFlags = 0; + if (DeploymentActiveAt(*pindex, m_params.GetConsensus(), Consensus::DEPLOYMENT_CSV)) { + nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE; + } + + // Get the script flags for this block + unsigned int flags{GetBlockScriptFlags(*pindex, m_params.GetConsensus())}; + + int64_t nTime2 = GetTimeMicros(); nTimeForks += nTime2 - nTime1; + LogPrint(BCLog::BENCH, " - Fork checks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime2 - nTime1), nTimeForks * MICRO, nTimeForks * MILLI / nBlocksTotal); + + CBlockUndo blockundo; + + // Precomputed transaction data pointers must not be invalidated + // until after `control` has run the script checks (potentially + // in multiple threads). Preallocate the vector size so a new allocation + // doesn't invalidate pointers into the vector, and keep txsdata in scope + // for as long as `control`. + CCheckQueueControl<CScriptCheck> control(fScriptChecks && g_parallel_script_checks ? &scriptcheckqueue : nullptr); + std::vector<PrecomputedTransactionData> txsdata(block.vtx.size()); + + std::vector<int> prevheights; + CAmount nFees = 0; + int nInputs = 0; + int64_t nSigOpsCost = 0; + blockundo.vtxundo.reserve(block.vtx.size() - 1); + for (unsigned int i = 0; i < block.vtx.size(); i++) + { + const CTransaction &tx = *(block.vtx[i]); + + nInputs += tx.vin.size(); + + if (!tx.IsCoinBase()) + { + CAmount txfee = 0; + TxValidationState tx_state; + if (!Consensus::CheckTxInputs(tx, tx_state, view, pindex->nHeight, txfee)) { + // Any transaction validation failure in ConnectBlock is a block consensus failure + state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, + tx_state.GetRejectReason(), tx_state.GetDebugMessage()); + return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), state.ToString()); + } + nFees += txfee; + if (!MoneyRange(nFees)) { + LogPrintf("ERROR: %s: accumulated fee in the block out of range.\n", __func__); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-accumulated-fee-outofrange"); + } + + // Check that transaction is BIP68 final + // BIP68 lock checks (as opposed to nLockTime checks) must + // be in ConnectBlock because they require the UTXO set + prevheights.resize(tx.vin.size()); + for (size_t j = 0; j < tx.vin.size(); j++) { + prevheights[j] = view.AccessCoin(tx.vin[j].prevout).nHeight; + } + + if (!SequenceLocks(tx, nLockTimeFlags, prevheights, *pindex)) { + LogPrintf("ERROR: %s: contains a non-BIP68-final transaction\n", __func__); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-nonfinal"); + } + } + + // GetTransactionSigOpCost counts 3 types of sigops: + // * legacy (always) + // * p2sh (when P2SH enabled in flags and excludes coinbase) + // * witness (when witness enabled in flags and excludes coinbase) + nSigOpsCost += GetTransactionSigOpCost(tx, view, flags); + if (nSigOpsCost > MAX_BLOCK_SIGOPS_COST) { + LogPrintf("ERROR: ConnectBlock(): too many sigops\n"); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-sigops"); + } + + if (!tx.IsCoinBase()) + { + std::vector<CScriptCheck> vChecks; + bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */ + TxValidationState tx_state; + if (fScriptChecks && !CheckInputScripts(tx, tx_state, view, flags, fCacheResults, fCacheResults, txsdata[i], g_parallel_script_checks ? &vChecks : nullptr)) { + // Any transaction validation failure in ConnectBlock is a block consensus failure + state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, + tx_state.GetRejectReason(), tx_state.GetDebugMessage()); + return error("ConnectBlock(): CheckInputScripts on %s failed with %s", + tx.GetHash().ToString(), state.ToString()); + } + control.Add(vChecks); + } + + CTxUndo undoDummy; + if (i > 0) { + blockundo.vtxundo.push_back(CTxUndo()); + } + UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight); + } + int64_t nTime3 = GetTimeMicros(); nTimeConnect += nTime3 - nTime2; + LogPrint(BCLog::BENCH, " - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs (%.2fms/blk)]\n", (unsigned)block.vtx.size(), MILLI * (nTime3 - nTime2), MILLI * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : MILLI * (nTime3 - nTime2) / (nInputs-1), nTimeConnect * MICRO, nTimeConnect * MILLI / nBlocksTotal); + + CAmount blockReward = nFees + GetBlockSubsidy(pindex->nHeight, m_params.GetConsensus()); + if (block.vtx[0]->GetValueOut() > blockReward) { + LogPrintf("ERROR: ConnectBlock(): coinbase pays too much (actual=%d vs limit=%d)\n", block.vtx[0]->GetValueOut(), blockReward); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-amount"); + } + + if (!control.Wait()) { + LogPrintf("ERROR: %s: CheckQueue failed\n", __func__); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "block-validation-failed"); + } + int64_t nTime4 = GetTimeMicros(); nTimeVerify += nTime4 - nTime2; + LogPrint(BCLog::BENCH, " - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs (%.2fms/blk)]\n", nInputs - 1, MILLI * (nTime4 - nTime2), nInputs <= 1 ? 0 : MILLI * (nTime4 - nTime2) / (nInputs-1), nTimeVerify * MICRO, nTimeVerify * MILLI / nBlocksTotal); + + if (fJustCheck) + return true; + + if (!m_blockman.WriteUndoDataForBlock(blockundo, state, pindex, m_params)) { + return false; + } + + int64_t nTime5 = GetTimeMicros(); nTimeUndo += nTime5 - nTime4; + LogPrint(BCLog::BENCH, " - Write undo data: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime5 - nTime4), nTimeUndo * MICRO, nTimeUndo * MILLI / nBlocksTotal); + + if (!pindex->IsValid(BLOCK_VALID_SCRIPTS)) { + pindex->RaiseValidity(BLOCK_VALID_SCRIPTS); + m_blockman.m_dirty_blockindex.insert(pindex); + } + + assert(pindex->phashBlock); + // add this block to the view's block chain + view.SetBestBlock(pindex->GetBlockHash()); + + int64_t nTime6 = GetTimeMicros(); nTimeIndex += nTime6 - nTime5; + LogPrint(BCLog::BENCH, " - Index writing: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime6 - nTime5), nTimeIndex * MICRO, nTimeIndex * MILLI / nBlocksTotal); + + TRACE6(validation, block_connected, + block_hash.data(), + pindex->nHeight, + block.vtx.size(), + nInputs, + nSigOpsCost, + nTime5 - nTimeStart // in microseconds (µs) + ); + + return true; +} + +CoinsCacheSizeState CChainState::GetCoinsCacheSizeState() +{ + AssertLockHeld(::cs_main); + return this->GetCoinsCacheSizeState( + m_coinstip_cache_size_bytes, + gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000); +} + +CoinsCacheSizeState CChainState::GetCoinsCacheSizeState( + size_t max_coins_cache_size_bytes, + size_t max_mempool_size_bytes) +{ + AssertLockHeld(::cs_main); + const int64_t nMempoolUsage = m_mempool ? m_mempool->DynamicMemoryUsage() : 0; + int64_t cacheSize = CoinsTip().DynamicMemoryUsage(); + int64_t nTotalSpace = + max_coins_cache_size_bytes + std::max<int64_t>(int64_t(max_mempool_size_bytes) - nMempoolUsage, 0); + + //! No need to periodic flush if at least this much space still available. + static constexpr int64_t MAX_BLOCK_COINSDB_USAGE_BYTES = 10 * 1024 * 1024; // 10MB + int64_t large_threshold = + std::max((9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE_BYTES); + + if (cacheSize > nTotalSpace) { + LogPrintf("Cache size (%s) exceeds total space (%s)\n", cacheSize, nTotalSpace); + return CoinsCacheSizeState::CRITICAL; + } else if (cacheSize > large_threshold) { + return CoinsCacheSizeState::LARGE; + } + return CoinsCacheSizeState::OK; +} + +bool CChainState::FlushStateToDisk( + BlockValidationState &state, + FlushStateMode mode, + int nManualPruneHeight) +{ + LOCK(cs_main); + assert(this->CanFlushToDisk()); + static std::chrono::microseconds nLastWrite{0}; + static std::chrono::microseconds nLastFlush{0}; + std::set<int> setFilesToPrune; + bool full_flush_completed = false; + + const size_t coins_count = CoinsTip().GetCacheSize(); + const size_t coins_mem_usage = CoinsTip().DynamicMemoryUsage(); + + try { + { + bool fFlushForPrune = false; + bool fDoFullFlush = false; + + CoinsCacheSizeState cache_state = GetCoinsCacheSizeState(); + LOCK(m_blockman.cs_LastBlockFile); + if (fPruneMode && (m_blockman.m_check_for_pruning || nManualPruneHeight > 0) && !fReindex) { + // make sure we don't prune above any of the prune locks bestblocks + // pruning is height-based + int last_prune{m_chain.Height()}; // last height we can prune + std::optional<std::string> limiting_lock; // prune lock that actually was the limiting factor, only used for logging + + for (const auto& prune_lock : m_blockman.m_prune_locks) { + if (prune_lock.second.height_first == std::numeric_limits<int>::max()) continue; + // Remove the buffer and one additional block here to get actual height that is outside of the buffer + const int lock_height{prune_lock.second.height_first - PRUNE_LOCK_BUFFER - 1}; + last_prune = std::max(1, std::min(last_prune, lock_height)); + if (last_prune == lock_height) { + limiting_lock = prune_lock.first; + } + } + + if (limiting_lock) { + LogPrint(BCLog::PRUNE, "%s limited pruning to height %d\n", limiting_lock.value(), last_prune); + } + + if (nManualPruneHeight > 0) { + LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune (manual)", BCLog::BENCH); + + m_blockman.FindFilesToPruneManual(setFilesToPrune, std::min(last_prune, nManualPruneHeight), m_chain.Height()); + } else { + LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune", BCLog::BENCH); + + m_blockman.FindFilesToPrune(setFilesToPrune, m_params.PruneAfterHeight(), m_chain.Height(), last_prune, IsInitialBlockDownload()); + m_blockman.m_check_for_pruning = false; + } + if (!setFilesToPrune.empty()) { + fFlushForPrune = true; + if (!m_blockman.m_have_pruned) { + m_blockman.m_block_tree_db->WriteFlag("prunedblockfiles", true); + m_blockman.m_have_pruned = true; + } + } + } + const auto nNow = GetTime<std::chrono::microseconds>(); + // Avoid writing/flushing immediately after startup. + if (nLastWrite.count() == 0) { + nLastWrite = nNow; + } + if (nLastFlush.count() == 0) { + nLastFlush = nNow; + } + // The cache is large and we're within 10% and 10 MiB of the limit, but we have time now (not in the middle of a block processing). + bool fCacheLarge = mode == FlushStateMode::PERIODIC && cache_state >= CoinsCacheSizeState::LARGE; + // The cache is over the limit, we have to write now. + bool fCacheCritical = mode == FlushStateMode::IF_NEEDED && cache_state >= CoinsCacheSizeState::CRITICAL; + // It's been a while since we wrote the block index to disk. Do this frequently, so we don't need to redownload after a crash. + bool fPeriodicWrite = mode == FlushStateMode::PERIODIC && nNow > nLastWrite + DATABASE_WRITE_INTERVAL; + // It's been very long since we flushed the cache. Do this infrequently, to optimize cache usage. + bool fPeriodicFlush = mode == FlushStateMode::PERIODIC && nNow > nLastFlush + DATABASE_FLUSH_INTERVAL; + // Combine all conditions that result in a full cache flush. + fDoFullFlush = (mode == FlushStateMode::ALWAYS) || fCacheLarge || fCacheCritical || fPeriodicFlush || fFlushForPrune; + // Write blocks and block index to disk. + if (fDoFullFlush || fPeriodicWrite) { + // Ensure we can write block index + if (!CheckDiskSpace(gArgs.GetBlocksDirPath())) { + return AbortNode(state, "Disk space is too low!", _("Disk space is too low!")); + } + { + LOG_TIME_MILLIS_WITH_CATEGORY("write block and undo data to disk", BCLog::BENCH); + + // First make sure all block and undo data is flushed to disk. + m_blockman.FlushBlockFile(); + } + + // Then update all block file information (which may refer to block and undo files). + { + LOG_TIME_MILLIS_WITH_CATEGORY("write block index to disk", BCLog::BENCH); + + if (!m_blockman.WriteBlockIndexDB()) { + return AbortNode(state, "Failed to write to block index database"); + } + } + // Finally remove any pruned files + if (fFlushForPrune) { + LOG_TIME_MILLIS_WITH_CATEGORY("unlink pruned files", BCLog::BENCH); + + UnlinkPrunedFiles(setFilesToPrune); + } + nLastWrite = nNow; + } + // Flush best chain related state. This can only be done if the blocks / block index write was also done. + if (fDoFullFlush && !CoinsTip().GetBestBlock().IsNull()) { + LOG_TIME_MILLIS_WITH_CATEGORY(strprintf("write coins cache to disk (%d coins, %.2fkB)", + coins_count, coins_mem_usage / 1000), BCLog::BENCH); + + // Typical Coin structures on disk are around 48 bytes in size. + // Pushing a new one to the database can cause it to be written + // twice (once in the log, and once in the tables). This is already + // an overestimation, as most will delete an existing entry or + // overwrite one. Still, use a conservative safety factor of 2. + if (!CheckDiskSpace(gArgs.GetDataDirNet(), 48 * 2 * 2 * CoinsTip().GetCacheSize())) { + return AbortNode(state, "Disk space is too low!", _("Disk space is too low!")); + } + // Flush the chainstate (which may refer to block index entries). + if (!CoinsTip().Flush()) + return AbortNode(state, "Failed to write to coin database"); + nLastFlush = nNow; + full_flush_completed = true; + TRACE5(utxocache, flush, + (int64_t)(GetTimeMicros() - nNow.count()), // in microseconds (µs) + (u_int32_t)mode, + (u_int64_t)coins_count, + (u_int64_t)coins_mem_usage, + (bool)fFlushForPrune); + } + } + if (full_flush_completed) { + // Update best block in wallet (so we can detect restored wallets). + GetMainSignals().ChainStateFlushed(m_chain.GetLocator()); + } + } catch (const std::runtime_error& e) { + return AbortNode(state, std::string("System error while flushing: ") + e.what()); + } + return true; +} + +void CChainState::ForceFlushStateToDisk() +{ + BlockValidationState state; + if (!this->FlushStateToDisk(state, FlushStateMode::ALWAYS)) { + LogPrintf("%s: failed to flush state (%s)\n", __func__, state.ToString()); + } +} + +void CChainState::PruneAndFlush() +{ + BlockValidationState state; + m_blockman.m_check_for_pruning = true; + if (!this->FlushStateToDisk(state, FlushStateMode::NONE)) { + LogPrintf("%s: failed to flush state (%s)\n", __func__, state.ToString()); + } +} + +static void DoWarning(const bilingual_str& warning) +{ + static bool fWarned = false; + SetMiscWarning(warning); + if (!fWarned) { + AlertNotify(warning.original); + fWarned = true; + } +} + +/** Private helper function that concatenates warning messages. */ +static void AppendWarning(bilingual_str& res, const bilingual_str& warn) +{ + if (!res.empty()) res += Untranslated(", "); + res += warn; +} + +static void UpdateTipLog( + const CCoinsViewCache& coins_tip, + const CBlockIndex* tip, + const CChainParams& params, + const std::string& func_name, + const std::string& prefix, + const std::string& warning_messages) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) +{ + + AssertLockHeld(::cs_main); + LogPrintf("%s%s: new best=%s height=%d version=0x%08x log2_work=%f tx=%lu date='%s' progress=%f cache=%.1fMiB(%utxo)%s\n", + prefix, func_name, + tip->GetBlockHash().ToString(), tip->nHeight, tip->nVersion, + log(tip->nChainWork.getdouble()) / log(2.0), (unsigned long)tip->nChainTx, + FormatISO8601DateTime(tip->GetBlockTime()), + GuessVerificationProgress(params.TxData(), tip), + coins_tip.DynamicMemoryUsage() * (1.0 / (1 << 20)), + coins_tip.GetCacheSize(), + !warning_messages.empty() ? strprintf(" warning='%s'", warning_messages) : ""); +} + +void CChainState::UpdateTip(const CBlockIndex* pindexNew) +{ + AssertLockHeld(::cs_main); + const auto& coins_tip = this->CoinsTip(); + + // The remainder of the function isn't relevant if we are not acting on + // the active chainstate, so return if need be. + if (this != &m_chainman.ActiveChainstate()) { + // Only log every so often so that we don't bury log messages at the tip. + constexpr int BACKGROUND_LOG_INTERVAL = 2000; + if (pindexNew->nHeight % BACKGROUND_LOG_INTERVAL == 0) { + UpdateTipLog(coins_tip, pindexNew, m_params, __func__, "[background validation] ", ""); + } + return; + } + + // New best block + if (m_mempool) { + m_mempool->AddTransactionsUpdated(1); + } + + { + LOCK(g_best_block_mutex); + g_best_block = pindexNew->GetBlockHash(); + g_best_block_cv.notify_all(); + } + + bilingual_str warning_messages; + if (!this->IsInitialBlockDownload()) { + const CBlockIndex* pindex = pindexNew; + for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) { + WarningBitsConditionChecker checker(bit); + ThresholdState state = checker.GetStateFor(pindex, m_params.GetConsensus(), warningcache.at(bit)); + if (state == ThresholdState::ACTIVE || state == ThresholdState::LOCKED_IN) { + const bilingual_str warning = strprintf(_("Unknown new rules activated (versionbit %i)"), bit); + if (state == ThresholdState::ACTIVE) { + DoWarning(warning); + } else { + AppendWarning(warning_messages, warning); + } + } + } + } + UpdateTipLog(coins_tip, pindexNew, m_params, __func__, "", warning_messages.original); +} + +/** Disconnect m_chain's tip. + * After calling, the mempool will be in an inconsistent state, with + * transactions from disconnected blocks being added to disconnectpool. You + * should make the mempool consistent again by calling MaybeUpdateMempoolForReorg. + * with cs_main held. + * + * If disconnectpool is nullptr, then no disconnected transactions are added to + * disconnectpool (note that the caller is responsible for mempool consistency + * in any case). + */ +bool CChainState::DisconnectTip(BlockValidationState& state, DisconnectedBlockTransactions* disconnectpool) +{ + AssertLockHeld(cs_main); + if (m_mempool) AssertLockHeld(m_mempool->cs); + + CBlockIndex *pindexDelete = m_chain.Tip(); + assert(pindexDelete); + // Read block from disk. + std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>(); + CBlock& block = *pblock; + if (!ReadBlockFromDisk(block, pindexDelete, m_params.GetConsensus())) { + return error("DisconnectTip(): Failed to read block"); + } + // Apply the block atomically to the chain state. + int64_t nStart = GetTimeMicros(); + { + CCoinsViewCache view(&CoinsTip()); + assert(view.GetBestBlock() == pindexDelete->GetBlockHash()); + if (DisconnectBlock(block, pindexDelete, view) != DISCONNECT_OK) + return error("DisconnectTip(): DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString()); + bool flushed = view.Flush(); + assert(flushed); + } + LogPrint(BCLog::BENCH, "- Disconnect block: %.2fms\n", (GetTimeMicros() - nStart) * MILLI); + + { + // Prune locks that began at or after the tip should be moved backward so they get a chance to reorg + const int max_height_first{pindexDelete->nHeight - 1}; + for (auto& prune_lock : m_blockman.m_prune_locks) { + if (prune_lock.second.height_first <= max_height_first) continue; + + prune_lock.second.height_first = max_height_first; + LogPrint(BCLog::PRUNE, "%s prune lock moved back to %d\n", prune_lock.first, max_height_first); + } + } + + // Write the chain state to disk, if necessary. + if (!FlushStateToDisk(state, FlushStateMode::IF_NEEDED)) { + return false; + } + + if (disconnectpool && m_mempool) { + // Save transactions to re-add to mempool at end of reorg + for (auto it = block.vtx.rbegin(); it != block.vtx.rend(); ++it) { + disconnectpool->addTransaction(*it); + } + while (disconnectpool->DynamicMemoryUsage() > MAX_DISCONNECTED_TX_POOL_SIZE * 1000) { + // Drop the earliest entry, and remove its children from the mempool. + auto it = disconnectpool->queuedTx.get<insertion_order>().begin(); + m_mempool->removeRecursive(**it, MemPoolRemovalReason::REORG); + disconnectpool->removeEntry(it); + } + } + + m_chain.SetTip(pindexDelete->pprev); + + UpdateTip(pindexDelete->pprev); + // Let wallets know transactions went from 1-confirmed to + // 0-confirmed or conflicted: + GetMainSignals().BlockDisconnected(pblock, pindexDelete); + return true; +} + +static int64_t nTimeReadFromDiskTotal = 0; +static int64_t nTimeConnectTotal = 0; +static int64_t nTimeFlush = 0; +static int64_t nTimeChainState = 0; +static int64_t nTimePostConnect = 0; + +struct PerBlockConnectTrace { + CBlockIndex* pindex = nullptr; + std::shared_ptr<const CBlock> pblock; + PerBlockConnectTrace() {} +}; +/** + * Used to track blocks whose transactions were applied to the UTXO state as a + * part of a single ActivateBestChainStep call. + * + * This class is single-use, once you call GetBlocksConnected() you have to throw + * it away and make a new one. + */ +class ConnectTrace { +private: + std::vector<PerBlockConnectTrace> blocksConnected; + +public: + explicit ConnectTrace() : blocksConnected(1) {} + + void BlockConnected(CBlockIndex* pindex, std::shared_ptr<const CBlock> pblock) { + assert(!blocksConnected.back().pindex); + assert(pindex); + assert(pblock); + blocksConnected.back().pindex = pindex; + blocksConnected.back().pblock = std::move(pblock); + blocksConnected.emplace_back(); + } + + std::vector<PerBlockConnectTrace>& GetBlocksConnected() { + // We always keep one extra block at the end of our list because + // blocks are added after all the conflicted transactions have + // been filled in. Thus, the last entry should always be an empty + // one waiting for the transactions from the next block. We pop + // the last entry here to make sure the list we return is sane. + assert(!blocksConnected.back().pindex); + blocksConnected.pop_back(); + return blocksConnected; + } +}; + +/** + * Connect a new block to m_chain. pblock is either nullptr or a pointer to a CBlock + * corresponding to pindexNew, to bypass loading it again from disk. + * + * The block is added to connectTrace if connection succeeds. + */ +bool CChainState::ConnectTip(BlockValidationState& state, CBlockIndex* pindexNew, const std::shared_ptr<const CBlock>& pblock, ConnectTrace& connectTrace, DisconnectedBlockTransactions& disconnectpool) +{ + AssertLockHeld(cs_main); + if (m_mempool) AssertLockHeld(m_mempool->cs); + + assert(pindexNew->pprev == m_chain.Tip()); + // Read block from disk. + int64_t nTime1 = GetTimeMicros(); + std::shared_ptr<const CBlock> pthisBlock; + if (!pblock) { + std::shared_ptr<CBlock> pblockNew = std::make_shared<CBlock>(); + if (!ReadBlockFromDisk(*pblockNew, pindexNew, m_params.GetConsensus())) { + return AbortNode(state, "Failed to read block"); + } + pthisBlock = pblockNew; + } else { + LogPrint(BCLog::BENCH, " - Using cached block\n"); + pthisBlock = pblock; + } + const CBlock& blockConnecting = *pthisBlock; + // Apply the block atomically to the chain state. + int64_t nTime2 = GetTimeMicros(); nTimeReadFromDiskTotal += nTime2 - nTime1; + int64_t nTime3; + LogPrint(BCLog::BENCH, " - Load block from disk: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime2 - nTime1) * MILLI, nTimeReadFromDiskTotal * MICRO, nTimeReadFromDiskTotal * MILLI / nBlocksTotal); + { + CCoinsViewCache view(&CoinsTip()); + bool rv = ConnectBlock(blockConnecting, state, pindexNew, view); + GetMainSignals().BlockChecked(blockConnecting, state); + if (!rv) { + if (state.IsInvalid()) + InvalidBlockFound(pindexNew, state); + return error("%s: ConnectBlock %s failed, %s", __func__, pindexNew->GetBlockHash().ToString(), state.ToString()); + } + nTime3 = GetTimeMicros(); nTimeConnectTotal += nTime3 - nTime2; + assert(nBlocksTotal > 0); + LogPrint(BCLog::BENCH, " - Connect total: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime3 - nTime2) * MILLI, nTimeConnectTotal * MICRO, nTimeConnectTotal * MILLI / nBlocksTotal); + bool flushed = view.Flush(); + assert(flushed); + } + int64_t nTime4 = GetTimeMicros(); nTimeFlush += nTime4 - nTime3; + LogPrint(BCLog::BENCH, " - Flush: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime4 - nTime3) * MILLI, nTimeFlush * MICRO, nTimeFlush * MILLI / nBlocksTotal); + // Write the chain state to disk, if necessary. + if (!FlushStateToDisk(state, FlushStateMode::IF_NEEDED)) { + return false; + } + int64_t nTime5 = GetTimeMicros(); nTimeChainState += nTime5 - nTime4; + LogPrint(BCLog::BENCH, " - Writing chainstate: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime5 - nTime4) * MILLI, nTimeChainState * MICRO, nTimeChainState * MILLI / nBlocksTotal); + // Remove conflicting transactions from the mempool.; + if (m_mempool) { + m_mempool->removeForBlock(blockConnecting.vtx, pindexNew->nHeight); + disconnectpool.removeForBlock(blockConnecting.vtx); + } + // Update m_chain & related variables. + m_chain.SetTip(pindexNew); + UpdateTip(pindexNew); + + int64_t nTime6 = GetTimeMicros(); nTimePostConnect += nTime6 - nTime5; nTimeTotal += nTime6 - nTime1; + LogPrint(BCLog::BENCH, " - Connect postprocess: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime6 - nTime5) * MILLI, nTimePostConnect * MICRO, nTimePostConnect * MILLI / nBlocksTotal); + LogPrint(BCLog::BENCH, "- Connect block: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime6 - nTime1) * MILLI, nTimeTotal * MICRO, nTimeTotal * MILLI / nBlocksTotal); + + connectTrace.BlockConnected(pindexNew, std::move(pthisBlock)); + return true; +} + +/** + * Return the tip of the chain with the most work in it, that isn't + * known to be invalid (it's however far from certain to be valid). + */ +CBlockIndex* CChainState::FindMostWorkChain() +{ + AssertLockHeld(::cs_main); + do { + CBlockIndex *pindexNew = nullptr; + + // Find the best candidate header. + { + std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexCandidates.rbegin(); + if (it == setBlockIndexCandidates.rend()) + return nullptr; + pindexNew = *it; + } + + // Check whether all blocks on the path between the currently active chain and the candidate are valid. + // Just going until the active chain is an optimization, as we know all blocks in it are valid already. + CBlockIndex *pindexTest = pindexNew; + bool fInvalidAncestor = false; + while (pindexTest && !m_chain.Contains(pindexTest)) { + assert(pindexTest->HaveTxsDownloaded() || pindexTest->nHeight == 0); + + // Pruned nodes may have entries in setBlockIndexCandidates for + // which block files have been deleted. Remove those as candidates + // for the most work chain if we come across them; we can't switch + // to a chain unless we have all the non-active-chain parent blocks. + bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK; + bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA); + if (fFailedChain || fMissingData) { + // Candidate chain is not usable (either invalid or missing data) + if (fFailedChain && (m_chainman.m_best_invalid == nullptr || pindexNew->nChainWork > m_chainman.m_best_invalid->nChainWork)) { + m_chainman.m_best_invalid = pindexNew; + } + CBlockIndex *pindexFailed = pindexNew; + // Remove the entire chain from the set. + while (pindexTest != pindexFailed) { + if (fFailedChain) { + pindexFailed->nStatus |= BLOCK_FAILED_CHILD; + } else if (fMissingData) { + // If we're missing data, then add back to m_blocks_unlinked, + // so that if the block arrives in the future we can try adding + // to setBlockIndexCandidates again. + m_blockman.m_blocks_unlinked.insert( + std::make_pair(pindexFailed->pprev, pindexFailed)); + } + setBlockIndexCandidates.erase(pindexFailed); + pindexFailed = pindexFailed->pprev; + } + setBlockIndexCandidates.erase(pindexTest); + fInvalidAncestor = true; + break; + } + pindexTest = pindexTest->pprev; + } + if (!fInvalidAncestor) + return pindexNew; + } while(true); +} + +/** Delete all entries in setBlockIndexCandidates that are worse than the current tip. */ +void CChainState::PruneBlockIndexCandidates() { + // Note that we can't delete the current block itself, as we may need to return to it later in case a + // reorganization to a better block fails. + std::set<CBlockIndex*, CBlockIndexWorkComparator>::iterator it = setBlockIndexCandidates.begin(); + while (it != setBlockIndexCandidates.end() && setBlockIndexCandidates.value_comp()(*it, m_chain.Tip())) { + setBlockIndexCandidates.erase(it++); + } + // Either the current tip or a successor of it we're working towards is left in setBlockIndexCandidates. + assert(!setBlockIndexCandidates.empty()); +} + +/** + * Try to make some progress towards making pindexMostWork the active block. + * pblock is either nullptr or a pointer to a CBlock corresponding to pindexMostWork. + * + * @returns true unless a system error occurred + */ +bool CChainState::ActivateBestChainStep(BlockValidationState& state, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace) +{ + AssertLockHeld(cs_main); + if (m_mempool) AssertLockHeld(m_mempool->cs); + + const CBlockIndex* pindexOldTip = m_chain.Tip(); + const CBlockIndex* pindexFork = m_chain.FindFork(pindexMostWork); + + // Disconnect active blocks which are no longer in the best chain. + bool fBlocksDisconnected = false; + DisconnectedBlockTransactions disconnectpool; + while (m_chain.Tip() && m_chain.Tip() != pindexFork) { + if (!DisconnectTip(state, &disconnectpool)) { + // This is likely a fatal error, but keep the mempool consistent, + // just in case. Only remove from the mempool in this case. + MaybeUpdateMempoolForReorg(disconnectpool, false); + + // If we're unable to disconnect a block during normal operation, + // then that is a failure of our local system -- we should abort + // rather than stay on a less work chain. + AbortNode(state, "Failed to disconnect block; see debug.log for details"); + return false; + } + fBlocksDisconnected = true; + } + + // Build list of new blocks to connect (in descending height order). + std::vector<CBlockIndex*> vpindexToConnect; + bool fContinue = true; + int nHeight = pindexFork ? pindexFork->nHeight : -1; + while (fContinue && nHeight != pindexMostWork->nHeight) { + // Don't iterate the entire list of potential improvements toward the best tip, as we likely only need + // a few blocks along the way. + int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight); + vpindexToConnect.clear(); + vpindexToConnect.reserve(nTargetHeight - nHeight); + CBlockIndex* pindexIter = pindexMostWork->GetAncestor(nTargetHeight); + while (pindexIter && pindexIter->nHeight != nHeight) { + vpindexToConnect.push_back(pindexIter); + pindexIter = pindexIter->pprev; + } + nHeight = nTargetHeight; + + // Connect new blocks. + for (CBlockIndex* pindexConnect : reverse_iterate(vpindexToConnect)) { + if (!ConnectTip(state, pindexConnect, pindexConnect == pindexMostWork ? pblock : std::shared_ptr<const CBlock>(), connectTrace, disconnectpool)) { + if (state.IsInvalid()) { + // The block violates a consensus rule. + if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) { + InvalidChainFound(vpindexToConnect.front()); + } + state = BlockValidationState(); + fInvalidFound = true; + fContinue = false; + break; + } else { + // A system error occurred (disk space, database error, ...). + // Make the mempool consistent with the current tip, just in case + // any observers try to use it before shutdown. + MaybeUpdateMempoolForReorg(disconnectpool, false); + return false; + } + } else { + PruneBlockIndexCandidates(); + if (!pindexOldTip || m_chain.Tip()->nChainWork > pindexOldTip->nChainWork) { + // We're in a better position than we were. Return temporarily to release the lock. + fContinue = false; + break; + } + } + } + } + + if (fBlocksDisconnected) { + // If any blocks were disconnected, disconnectpool may be non empty. Add + // any disconnected transactions back to the mempool. + MaybeUpdateMempoolForReorg(disconnectpool, true); + } + if (m_mempool) m_mempool->check(this->CoinsTip(), this->m_chain.Height() + 1); + + CheckForkWarningConditions(); + + return true; +} + +static SynchronizationState GetSynchronizationState(bool init) +{ + if (!init) return SynchronizationState::POST_INIT; + if (::fReindex) return SynchronizationState::INIT_REINDEX; + return SynchronizationState::INIT_DOWNLOAD; +} + +static bool NotifyHeaderTip(CChainState& chainstate) LOCKS_EXCLUDED(cs_main) { + bool fNotify = false; + bool fInitialBlockDownload = false; + static CBlockIndex* pindexHeaderOld = nullptr; + CBlockIndex* pindexHeader = nullptr; + { + LOCK(cs_main); + pindexHeader = chainstate.m_chainman.m_best_header; + + if (pindexHeader != pindexHeaderOld) { + fNotify = true; + fInitialBlockDownload = chainstate.IsInitialBlockDownload(); + pindexHeaderOld = pindexHeader; + } + } + // Send block tip changed notifications without cs_main + if (fNotify) { + uiInterface.NotifyHeaderTip(GetSynchronizationState(fInitialBlockDownload), pindexHeader); + } + return fNotify; +} + +static void LimitValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main) { + AssertLockNotHeld(cs_main); + + if (GetMainSignals().CallbacksPending() > 10) { + SyncWithValidationInterfaceQueue(); + } +} + +bool CChainState::ActivateBestChain(BlockValidationState& state, std::shared_ptr<const CBlock> pblock) +{ + AssertLockNotHeld(m_chainstate_mutex); + + // Note that while we're often called here from ProcessNewBlock, this is + // far from a guarantee. Things in the P2P/RPC will often end up calling + // us in the middle of ProcessNewBlock - do not assume pblock is set + // sanely for performance or correctness! + AssertLockNotHeld(::cs_main); + + // ABC maintains a fair degree of expensive-to-calculate internal state + // because this function periodically releases cs_main so that it does not lock up other threads for too long + // during large connects - and to allow for e.g. the callback queue to drain + // we use m_chainstate_mutex to enforce mutual exclusion so that only one caller may execute this function at a time + LOCK(m_chainstate_mutex); + + CBlockIndex *pindexMostWork = nullptr; + CBlockIndex *pindexNewTip = nullptr; + int nStopAtHeight = gArgs.GetIntArg("-stopatheight", DEFAULT_STOPATHEIGHT); + do { + // Block until the validation queue drains. This should largely + // never happen in normal operation, however may happen during + // reindex, causing memory blowup if we run too far ahead. + // Note that if a validationinterface callback ends up calling + // ActivateBestChain this may lead to a deadlock! We should + // probably have a DEBUG_LOCKORDER test for this in the future. + LimitValidationInterfaceQueue(); + + { + LOCK(cs_main); + // Lock transaction pool for at least as long as it takes for connectTrace to be consumed + LOCK(MempoolMutex()); + CBlockIndex* starting_tip = m_chain.Tip(); + bool blocks_connected = false; + do { + // We absolutely may not unlock cs_main until we've made forward progress + // (with the exception of shutdown due to hardware issues, low disk space, etc). + ConnectTrace connectTrace; // Destructed before cs_main is unlocked + + if (pindexMostWork == nullptr) { + pindexMostWork = FindMostWorkChain(); + } + + // Whether we have anything to do at all. + if (pindexMostWork == nullptr || pindexMostWork == m_chain.Tip()) { + break; + } + + bool fInvalidFound = false; + std::shared_ptr<const CBlock> nullBlockPtr; + if (!ActivateBestChainStep(state, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace)) { + // A system error occurred + return false; + } + blocks_connected = true; + + if (fInvalidFound) { + // Wipe cache, we may need another branch now. + pindexMostWork = nullptr; + } + pindexNewTip = m_chain.Tip(); + + for (const PerBlockConnectTrace& trace : connectTrace.GetBlocksConnected()) { + assert(trace.pblock && trace.pindex); + GetMainSignals().BlockConnected(trace.pblock, trace.pindex); + } + } while (!m_chain.Tip() || (starting_tip && CBlockIndexWorkComparator()(m_chain.Tip(), starting_tip))); + if (!blocks_connected) return true; + + const CBlockIndex* pindexFork = m_chain.FindFork(starting_tip); + bool fInitialDownload = IsInitialBlockDownload(); + + // Notify external listeners about the new tip. + // Enqueue while holding cs_main to ensure that UpdatedBlockTip is called in the order in which blocks are connected + if (pindexFork != pindexNewTip) { + // Notify ValidationInterface subscribers + GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload); + + // Always notify the UI if a new block tip was connected + uiInterface.NotifyBlockTip(GetSynchronizationState(fInitialDownload), pindexNewTip); + } + } + // When we reach this point, we switched to a new tip (stored in pindexNewTip). + + if (nStopAtHeight && pindexNewTip && pindexNewTip->nHeight >= nStopAtHeight) StartShutdown(); + + // We check shutdown only after giving ActivateBestChainStep a chance to run once so that we + // never shutdown before connecting the genesis block during LoadChainTip(). Previously this + // caused an assert() failure during shutdown in such cases as the UTXO DB flushing checks + // that the best block hash is non-null. + if (ShutdownRequested()) break; + } while (pindexNewTip != pindexMostWork); + CheckBlockIndex(); + + // Write changes periodically to disk, after relay. + if (!FlushStateToDisk(state, FlushStateMode::PERIODIC)) { + return false; + } + + return true; +} + +bool CChainState::PreciousBlock(BlockValidationState& state, CBlockIndex* pindex) +{ + AssertLockNotHeld(m_chainstate_mutex); + AssertLockNotHeld(::cs_main); + { + LOCK(cs_main); + if (pindex->nChainWork < m_chain.Tip()->nChainWork) { + // Nothing to do, this block is not at the tip. + return true; + } + if (m_chain.Tip()->nChainWork > nLastPreciousChainwork) { + // The chain has been extended since the last call, reset the counter. + nBlockReverseSequenceId = -1; + } + nLastPreciousChainwork = m_chain.Tip()->nChainWork; + setBlockIndexCandidates.erase(pindex); + pindex->nSequenceId = nBlockReverseSequenceId; + if (nBlockReverseSequenceId > std::numeric_limits<int32_t>::min()) { + // We can't keep reducing the counter if somebody really wants to + // call preciousblock 2**31-1 times on the same set of tips... + nBlockReverseSequenceId--; + } + if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && pindex->HaveTxsDownloaded()) { + setBlockIndexCandidates.insert(pindex); + PruneBlockIndexCandidates(); + } + } + + return ActivateBestChain(state, std::shared_ptr<const CBlock>()); +} + +bool CChainState::InvalidateBlock(BlockValidationState& state, CBlockIndex* pindex) +{ + AssertLockNotHeld(m_chainstate_mutex); + AssertLockNotHeld(::cs_main); + + // Genesis block can't be invalidated + assert(pindex); + if (pindex->nHeight == 0) return false; + + CBlockIndex* to_mark_failed = pindex; + bool pindex_was_in_chain = false; + int disconnected = 0; + + // We do not allow ActivateBestChain() to run while InvalidateBlock() is + // running, as that could cause the tip to change while we disconnect + // blocks. + LOCK(m_chainstate_mutex); + + // We'll be acquiring and releasing cs_main below, to allow the validation + // callbacks to run. However, we should keep the block index in a + // consistent state as we disconnect blocks -- in particular we need to + // add equal-work blocks to setBlockIndexCandidates as we disconnect. + // To avoid walking the block index repeatedly in search of candidates, + // build a map once so that we can look up candidate blocks by chain + // work as we go. + std::multimap<const arith_uint256, CBlockIndex *> candidate_blocks_by_work; + + { + LOCK(cs_main); + for (auto& entry : m_blockman.m_block_index) { + CBlockIndex* candidate = &entry.second; + // We don't need to put anything in our active chain into the + // multimap, because those candidates will be found and considered + // as we disconnect. + // Instead, consider only non-active-chain blocks that have at + // least as much work as where we expect the new tip to end up. + if (!m_chain.Contains(candidate) && + !CBlockIndexWorkComparator()(candidate, pindex->pprev) && + candidate->IsValid(BLOCK_VALID_TRANSACTIONS) && + candidate->HaveTxsDownloaded()) { + candidate_blocks_by_work.insert(std::make_pair(candidate->nChainWork, candidate)); + } + } + } + + // Disconnect (descendants of) pindex, and mark them invalid. + while (true) { + if (ShutdownRequested()) break; + + // Make sure the queue of validation callbacks doesn't grow unboundedly. + LimitValidationInterfaceQueue(); + + LOCK(cs_main); + // Lock for as long as disconnectpool is in scope to make sure MaybeUpdateMempoolForReorg is + // called after DisconnectTip without unlocking in between + LOCK(MempoolMutex()); + if (!m_chain.Contains(pindex)) break; + pindex_was_in_chain = true; + CBlockIndex *invalid_walk_tip = m_chain.Tip(); + + // ActivateBestChain considers blocks already in m_chain + // unconditionally valid already, so force disconnect away from it. + DisconnectedBlockTransactions disconnectpool; + bool ret = DisconnectTip(state, &disconnectpool); + // DisconnectTip will add transactions to disconnectpool. + // Adjust the mempool to be consistent with the new tip, adding + // transactions back to the mempool if disconnecting was successful, + // and we're not doing a very deep invalidation (in which case + // keeping the mempool up to date is probably futile anyway). + MaybeUpdateMempoolForReorg(disconnectpool, /* fAddToMempool = */ (++disconnected <= 10) && ret); + if (!ret) return false; + assert(invalid_walk_tip->pprev == m_chain.Tip()); + + // We immediately mark the disconnected blocks as invalid. + // This prevents a case where pruned nodes may fail to invalidateblock + // and be left unable to start as they have no tip candidates (as there + // are no blocks that meet the "have data and are not invalid per + // nStatus" criteria for inclusion in setBlockIndexCandidates). + invalid_walk_tip->nStatus |= BLOCK_FAILED_VALID; + m_blockman.m_dirty_blockindex.insert(invalid_walk_tip); + setBlockIndexCandidates.erase(invalid_walk_tip); + setBlockIndexCandidates.insert(invalid_walk_tip->pprev); + if (invalid_walk_tip->pprev == to_mark_failed && (to_mark_failed->nStatus & BLOCK_FAILED_VALID)) { + // We only want to mark the last disconnected block as BLOCK_FAILED_VALID; its children + // need to be BLOCK_FAILED_CHILD instead. + to_mark_failed->nStatus = (to_mark_failed->nStatus ^ BLOCK_FAILED_VALID) | BLOCK_FAILED_CHILD; + m_blockman.m_dirty_blockindex.insert(to_mark_failed); + } + + // Add any equal or more work headers to setBlockIndexCandidates + auto candidate_it = candidate_blocks_by_work.lower_bound(invalid_walk_tip->pprev->nChainWork); + while (candidate_it != candidate_blocks_by_work.end()) { + if (!CBlockIndexWorkComparator()(candidate_it->second, invalid_walk_tip->pprev)) { + setBlockIndexCandidates.insert(candidate_it->second); + candidate_it = candidate_blocks_by_work.erase(candidate_it); + } else { + ++candidate_it; + } + } + + // Track the last disconnected block, so we can correct its BLOCK_FAILED_CHILD status in future + // iterations, or, if it's the last one, call InvalidChainFound on it. + to_mark_failed = invalid_walk_tip; + } + + CheckBlockIndex(); + + { + LOCK(cs_main); + if (m_chain.Contains(to_mark_failed)) { + // If the to-be-marked invalid block is in the active chain, something is interfering and we can't proceed. + return false; + } + + // Mark pindex (or the last disconnected block) as invalid, even when it never was in the main chain + to_mark_failed->nStatus |= BLOCK_FAILED_VALID; + m_blockman.m_dirty_blockindex.insert(to_mark_failed); + setBlockIndexCandidates.erase(to_mark_failed); + m_chainman.m_failed_blocks.insert(to_mark_failed); + + // If any new blocks somehow arrived while we were disconnecting + // (above), then the pre-calculation of what should go into + // setBlockIndexCandidates may have missed entries. This would + // technically be an inconsistency in the block index, but if we clean + // it up here, this should be an essentially unobservable error. + // Loop back over all block index entries and add any missing entries + // to setBlockIndexCandidates. + for (auto& [_, block_index] : m_blockman.m_block_index) { + if (block_index.IsValid(BLOCK_VALID_TRANSACTIONS) && block_index.HaveTxsDownloaded() && !setBlockIndexCandidates.value_comp()(&block_index, m_chain.Tip())) { + setBlockIndexCandidates.insert(&block_index); + } + } + + InvalidChainFound(to_mark_failed); + } + + // Only notify about a new block tip if the active chain was modified. + if (pindex_was_in_chain) { + uiInterface.NotifyBlockTip(GetSynchronizationState(IsInitialBlockDownload()), to_mark_failed->pprev); + } + return true; +} + +void CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) { + AssertLockHeld(cs_main); + + int nHeight = pindex->nHeight; + + // Remove the invalidity flag from this block and all its descendants. + for (auto& [_, block_index] : m_blockman.m_block_index) { + if (!block_index.IsValid() && block_index.GetAncestor(nHeight) == pindex) { + block_index.nStatus &= ~BLOCK_FAILED_MASK; + m_blockman.m_dirty_blockindex.insert(&block_index); + if (block_index.IsValid(BLOCK_VALID_TRANSACTIONS) && block_index.HaveTxsDownloaded() && setBlockIndexCandidates.value_comp()(m_chain.Tip(), &block_index)) { + setBlockIndexCandidates.insert(&block_index); + } + if (&block_index == m_chainman.m_best_invalid) { + // Reset invalid block marker if it was pointing to one of those. + m_chainman.m_best_invalid = nullptr; + } + m_chainman.m_failed_blocks.erase(&block_index); + } + } + + // Remove the invalidity flag from all ancestors too. + while (pindex != nullptr) { + if (pindex->nStatus & BLOCK_FAILED_MASK) { + pindex->nStatus &= ~BLOCK_FAILED_MASK; + m_blockman.m_dirty_blockindex.insert(pindex); + m_chainman.m_failed_blocks.erase(pindex); + } + pindex = pindex->pprev; + } +} + +/** Mark a block as having its data received and checked (up to BLOCK_VALID_TRANSACTIONS). */ +void CChainState::ReceivedBlockTransactions(const CBlock& block, CBlockIndex* pindexNew, const FlatFilePos& pos) +{ + AssertLockHeld(cs_main); + pindexNew->nTx = block.vtx.size(); + pindexNew->nChainTx = 0; + pindexNew->nFile = pos.nFile; + pindexNew->nDataPos = pos.nPos; + pindexNew->nUndoPos = 0; + pindexNew->nStatus |= BLOCK_HAVE_DATA; + if (DeploymentActiveAt(*pindexNew, m_params.GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) { + pindexNew->nStatus |= BLOCK_OPT_WITNESS; + } + pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS); + m_blockman.m_dirty_blockindex.insert(pindexNew); + + if (pindexNew->pprev == nullptr || pindexNew->pprev->HaveTxsDownloaded()) { + // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS. + std::deque<CBlockIndex*> queue; + queue.push_back(pindexNew); + + // Recursively process any descendant blocks that now may be eligible to be connected. + while (!queue.empty()) { + CBlockIndex *pindex = queue.front(); + queue.pop_front(); + pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx; + pindex->nSequenceId = nBlockSequenceId++; + if (m_chain.Tip() == nullptr || !setBlockIndexCandidates.value_comp()(pindex, m_chain.Tip())) { + setBlockIndexCandidates.insert(pindex); + } + std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = m_blockman.m_blocks_unlinked.equal_range(pindex); + while (range.first != range.second) { + std::multimap<CBlockIndex*, CBlockIndex*>::iterator it = range.first; + queue.push_back(it->second); + range.first++; + m_blockman.m_blocks_unlinked.erase(it); + } + } + } else { + if (pindexNew->pprev && pindexNew->pprev->IsValid(BLOCK_VALID_TREE)) { + m_blockman.m_blocks_unlinked.insert(std::make_pair(pindexNew->pprev, pindexNew)); + } + } +} + +static bool CheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true) +{ + // Check proof of work matches claimed amount + if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams)) + return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "high-hash", "proof of work failed"); + + return true; +} + +bool CheckBlock(const CBlock& block, BlockValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW, bool fCheckMerkleRoot) +{ + // These are checks that are independent of context. + + if (block.fChecked) + return true; + + // Check that the header is valid (particularly PoW). This is mostly + // redundant with the call in AcceptBlockHeader. + if (!CheckBlockHeader(block, state, consensusParams, fCheckPOW)) + return false; + + // Signet only: check block solution + if (consensusParams.signet_blocks && fCheckPOW && !CheckSignetBlockSolution(block, consensusParams)) { + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-signet-blksig", "signet block signature validation failure"); + } + + // Check the merkle root. + if (fCheckMerkleRoot) { + bool mutated; + uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated); + if (block.hashMerkleRoot != hashMerkleRoot2) + return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-txnmrklroot", "hashMerkleRoot mismatch"); + + // Check for merkle tree malleability (CVE-2012-2459): repeating sequences + // of transactions in a block without affecting the merkle root of a block, + // while still invalidating it. + if (mutated) + return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-txns-duplicate", "duplicate transaction"); + } + + // All potential-corruption validation must be done before we do any + // transaction validation, as otherwise we may mark the header as invalid + // because we receive the wrong transactions for it. + // Note that witness malleability is checked in ContextualCheckBlock, so no + // checks that use witness data may be performed here. + + // Size limits + if (block.vtx.empty() || block.vtx.size() * WITNESS_SCALE_FACTOR > MAX_BLOCK_WEIGHT || ::GetSerializeSize(block, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) * WITNESS_SCALE_FACTOR > MAX_BLOCK_WEIGHT) + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-length", "size limits failed"); + + // First transaction must be coinbase, the rest must not be + if (block.vtx.empty() || !block.vtx[0]->IsCoinBase()) + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-missing", "first tx is not coinbase"); + for (unsigned int i = 1; i < block.vtx.size(); i++) + if (block.vtx[i]->IsCoinBase()) + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-multiple", "more than one coinbase"); + + // Check transactions + // Must check for duplicate inputs (see CVE-2018-17144) + for (const auto& tx : block.vtx) { + TxValidationState tx_state; + if (!CheckTransaction(*tx, tx_state)) { + // CheckBlock() does context-free validation checks. The only + // possible failures are consensus failures. + assert(tx_state.GetResult() == TxValidationResult::TX_CONSENSUS); + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, tx_state.GetRejectReason(), + strprintf("Transaction check failed (tx hash %s) %s", tx->GetHash().ToString(), tx_state.GetDebugMessage())); + } + } + unsigned int nSigOps = 0; + for (const auto& tx : block.vtx) + { + nSigOps += GetLegacySigOpCount(*tx); + } + if (nSigOps * WITNESS_SCALE_FACTOR > MAX_BLOCK_SIGOPS_COST) + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-sigops", "out-of-bounds SigOpCount"); + + if (fCheckPOW && fCheckMerkleRoot) + block.fChecked = true; + + return true; +} + +void UpdateUncommittedBlockStructures(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams) +{ + int commitpos = GetWitnessCommitmentIndex(block); + static const std::vector<unsigned char> nonce(32, 0x00); + if (commitpos != NO_WITNESS_COMMITMENT && DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT) && !block.vtx[0]->HasWitness()) { + CMutableTransaction tx(*block.vtx[0]); + tx.vin[0].scriptWitness.stack.resize(1); + tx.vin[0].scriptWitness.stack[0] = nonce; + block.vtx[0] = MakeTransactionRef(std::move(tx)); + } +} + +std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams) +{ + std::vector<unsigned char> commitment; + int commitpos = GetWitnessCommitmentIndex(block); + std::vector<unsigned char> ret(32, 0x00); + if (commitpos == NO_WITNESS_COMMITMENT) { + uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr); + CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot); + CTxOut out; + out.nValue = 0; + out.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT); + out.scriptPubKey[0] = OP_RETURN; + out.scriptPubKey[1] = 0x24; + out.scriptPubKey[2] = 0xaa; + out.scriptPubKey[3] = 0x21; + out.scriptPubKey[4] = 0xa9; + out.scriptPubKey[5] = 0xed; + memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32); + commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end()); + CMutableTransaction tx(*block.vtx[0]); + tx.vout.push_back(out); + block.vtx[0] = MakeTransactionRef(std::move(tx)); + } + UpdateUncommittedBlockStructures(block, pindexPrev, consensusParams); + return commitment; +} + +/** Context-dependent validity checks. + * By "context", we mean only the previous block headers, but not the UTXO + * set; UTXO-related validity checks are done in ConnectBlock(). + * NOTE: This function is not currently invoked by ConnectBlock(), so we + * should consider upgrade issues if we change which consensus rules are + * enforced in this function (eg by adding a new consensus rule). See comment + * in ConnectBlock(). + * Note that -reindex-chainstate skips the validation that happens here! + */ +static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, BlockManager& blockman, const CChainParams& params, const CBlockIndex* pindexPrev, int64_t nAdjustedTime) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) +{ + AssertLockHeld(::cs_main); + assert(pindexPrev != nullptr); + const int nHeight = pindexPrev->nHeight + 1; + + // Check proof of work + const Consensus::Params& consensusParams = params.GetConsensus(); + if (block.nBits != GetNextWorkRequired(pindexPrev, &block, consensusParams)) + return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "bad-diffbits", "incorrect proof of work"); + + // Check against checkpoints + if (fCheckpointsEnabled) { + // Don't accept any forks from the main chain prior to last checkpoint. + // GetLastCheckpoint finds the last checkpoint in MapCheckpoints that's in our + // BlockIndex(). + const CBlockIndex* pcheckpoint = blockman.GetLastCheckpoint(params.Checkpoints()); + if (pcheckpoint && nHeight < pcheckpoint->nHeight) { + LogPrintf("ERROR: %s: forked chain older than last checkpoint (height %d)\n", __func__, nHeight); + return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT, "bad-fork-prior-to-checkpoint"); + } + } + + // Check timestamp against prev + if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast()) + return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "time-too-old", "block's timestamp is too early"); + + // Check timestamp + if (block.GetBlockTime() > nAdjustedTime + MAX_FUTURE_BLOCK_TIME) + return state.Invalid(BlockValidationResult::BLOCK_TIME_FUTURE, "time-too-new", "block timestamp too far in the future"); + + // Reject blocks with outdated version + if ((block.nVersion < 2 && DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_HEIGHTINCB)) || + (block.nVersion < 3 && DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_DERSIG)) || + (block.nVersion < 4 && DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CLTV))) { + return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, strprintf("bad-version(0x%08x)", block.nVersion), + strprintf("rejected nVersion=0x%08x block", block.nVersion)); + } + + return true; +} + +/** NOTE: This function is not currently invoked by ConnectBlock(), so we + * should consider upgrade issues if we change which consensus rules are + * enforced in this function (eg by adding a new consensus rule). See comment + * in ConnectBlock(). + * Note that -reindex-chainstate skips the validation that happens here! + */ +static bool ContextualCheckBlock(const CBlock& block, BlockValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev) +{ + const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1; + + // Enforce BIP113 (Median Time Past). + int nLockTimeFlags = 0; + if (DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CSV)) { + assert(pindexPrev != nullptr); + nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST; + } + + int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST) + ? pindexPrev->GetMedianTimePast() + : block.GetBlockTime(); + + // Check that all transactions are finalized + for (const auto& tx : block.vtx) { + if (!IsFinalTx(*tx, nHeight, nLockTimeCutoff)) { + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-nonfinal", "non-final transaction"); + } + } + + // Enforce rule that the coinbase starts with serialized block height + if (DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_HEIGHTINCB)) + { + CScript expect = CScript() << nHeight; + if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() || + !std::equal(expect.begin(), expect.end(), block.vtx[0]->vin[0].scriptSig.begin())) { + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-height", "block height mismatch in coinbase"); + } + } + + // Validation for witness commitments. + // * We compute the witness hash (which is the hash including witnesses) of all the block's transactions, except the + // coinbase (where 0x0000....0000 is used instead). + // * The coinbase scriptWitness is a stack of a single 32-byte vector, containing a witness reserved value (unconstrained). + // * We build a merkle tree with all those witness hashes as leaves (similar to the hashMerkleRoot in the block header). + // * There must be at least one output whose scriptPubKey is a single 36-byte push, the first 4 bytes of which are + // {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness reserved value). In case there are + // multiple, the last one is used. + bool fHaveWitness = false; + if (DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT)) { + int commitpos = GetWitnessCommitmentIndex(block); + if (commitpos != NO_WITNESS_COMMITMENT) { + bool malleated = false; + uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated); + // The malleation check is ignored; as the transaction tree itself + // already does not permit it, it is impossible to trigger in the + // witness tree. + if (block.vtx[0]->vin[0].scriptWitness.stack.size() != 1 || block.vtx[0]->vin[0].scriptWitness.stack[0].size() != 32) { + return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-witness-nonce-size", strprintf("%s : invalid witness reserved value size", __func__)); + } + CHash256().Write(hashWitness).Write(block.vtx[0]->vin[0].scriptWitness.stack[0]).Finalize(hashWitness); + if (memcmp(hashWitness.begin(), &block.vtx[0]->vout[commitpos].scriptPubKey[6], 32)) { + return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-witness-merkle-match", strprintf("%s : witness merkle commitment mismatch", __func__)); + } + fHaveWitness = true; + } + } + + // No witness data is allowed in blocks that don't commit to witness data, as this would otherwise leave room for spam + if (!fHaveWitness) { + for (const auto& tx : block.vtx) { + if (tx->HasWitness()) { + return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "unexpected-witness", strprintf("%s : unexpected witness data found", __func__)); + } + } + } + + // After the coinbase witness reserved value and commitment are verified, + // we can check if the block weight passes (before we've checked the + // coinbase witness, it would be possible for the weight to be too + // large by filling up the coinbase witness, which doesn't change + // the block hash, so we couldn't mark the block as permanently + // failed). + if (GetBlockWeight(block) > MAX_BLOCK_WEIGHT) { + return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-weight", strprintf("%s : weight limit failed", __func__)); + } + + return true; +} + +bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex) +{ + AssertLockHeld(cs_main); + // Check for duplicate + uint256 hash = block.GetHash(); + BlockMap::iterator miSelf{m_blockman.m_block_index.find(hash)}; + if (hash != chainparams.GetConsensus().hashGenesisBlock) { + if (miSelf != m_blockman.m_block_index.end()) { + // Block header is already known. + CBlockIndex* pindex = &(miSelf->second); + if (ppindex) + *ppindex = pindex; + if (pindex->nStatus & BLOCK_FAILED_MASK) { + LogPrint(BCLog::VALIDATION, "%s: block %s is marked invalid\n", __func__, hash.ToString()); + return state.Invalid(BlockValidationResult::BLOCK_CACHED_INVALID, "duplicate"); + } + return true; + } + + if (!CheckBlockHeader(block, state, chainparams.GetConsensus())) { + LogPrint(BCLog::VALIDATION, "%s: Consensus::CheckBlockHeader: %s, %s\n", __func__, hash.ToString(), state.ToString()); + return false; + } + + // Get prev block index + CBlockIndex* pindexPrev = nullptr; + BlockMap::iterator mi{m_blockman.m_block_index.find(block.hashPrevBlock)}; + if (mi == m_blockman.m_block_index.end()) { + LogPrint(BCLog::VALIDATION, "%s: %s prev block not found\n", __func__, hash.ToString()); + return state.Invalid(BlockValidationResult::BLOCK_MISSING_PREV, "prev-blk-not-found"); + } + pindexPrev = &((*mi).second); + if (pindexPrev->nStatus & BLOCK_FAILED_MASK) { + LogPrint(BCLog::VALIDATION, "%s: %s prev block invalid\n", __func__, hash.ToString()); + return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk"); + } + if (!ContextualCheckBlockHeader(block, state, m_blockman, chainparams, pindexPrev, GetAdjustedTime())) { + LogPrint(BCLog::VALIDATION, "%s: Consensus::ContextualCheckBlockHeader: %s, %s\n", __func__, hash.ToString(), state.ToString()); + return false; + } + + /* Determine if this block descends from any block which has been found + * invalid (m_failed_blocks), then mark pindexPrev and any blocks between + * them as failed. For example: + * + * D3 + * / + * B2 - C2 + * / \ + * A D2 - E2 - F2 + * \ + * B1 - C1 - D1 - E1 + * + * In the case that we attempted to reorg from E1 to F2, only to find + * C2 to be invalid, we would mark D2, E2, and F2 as BLOCK_FAILED_CHILD + * but NOT D3 (it was not in any of our candidate sets at the time). + * + * In any case D3 will also be marked as BLOCK_FAILED_CHILD at restart + * in LoadBlockIndex. + */ + if (!pindexPrev->IsValid(BLOCK_VALID_SCRIPTS)) { + // The above does not mean "invalid": it checks if the previous block + // hasn't been validated up to BLOCK_VALID_SCRIPTS. This is a performance + // optimization, in the common case of adding a new block to the tip, + // we don't need to iterate over the failed blocks list. + for (const CBlockIndex* failedit : m_failed_blocks) { + if (pindexPrev->GetAncestor(failedit->nHeight) == failedit) { + assert(failedit->nStatus & BLOCK_FAILED_VALID); + CBlockIndex* invalid_walk = pindexPrev; + while (invalid_walk != failedit) { + invalid_walk->nStatus |= BLOCK_FAILED_CHILD; + m_blockman.m_dirty_blockindex.insert(invalid_walk); + invalid_walk = invalid_walk->pprev; + } + LogPrint(BCLog::VALIDATION, "%s: %s prev block invalid\n", __func__, hash.ToString()); + return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk"); + } + } + } + } + CBlockIndex* pindex{m_blockman.AddToBlockIndex(block, m_best_header)}; + + if (ppindex) + *ppindex = pindex; + + return true; +} + +// Exposed wrapper for AcceptBlockHeader +bool ChainstateManager::ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, BlockValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex) +{ + AssertLockNotHeld(cs_main); + { + LOCK(cs_main); + for (const CBlockHeader& header : headers) { + CBlockIndex *pindex = nullptr; // Use a temp pindex instead of ppindex to avoid a const_cast + bool accepted{AcceptBlockHeader(header, state, chainparams, &pindex)}; + ActiveChainstate().CheckBlockIndex(); + + if (!accepted) { + return false; + } + if (ppindex) { + *ppindex = pindex; + } + } + } + if (NotifyHeaderTip(ActiveChainstate())) { + if (ActiveChainstate().IsInitialBlockDownload() && ppindex && *ppindex) { + const CBlockIndex& last_accepted{**ppindex}; + const int64_t blocks_left{(GetTime() - last_accepted.GetBlockTime()) / chainparams.GetConsensus().nPowTargetSpacing}; + const double progress{100.0 * last_accepted.nHeight / (last_accepted.nHeight + blocks_left)}; + LogPrintf("Synchronizing blockheaders, height: %d (~%.2f%%)\n", last_accepted.nHeight, progress); + } + } + return true; +} + +/** Store block on disk. If dbp is non-nullptr, the file is known to already reside on disk */ +bool CChainState::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, CBlockIndex** ppindex, bool fRequested, const FlatFilePos* dbp, bool* fNewBlock) +{ + const CBlock& block = *pblock; + + if (fNewBlock) *fNewBlock = false; + AssertLockHeld(cs_main); + + CBlockIndex *pindexDummy = nullptr; + CBlockIndex *&pindex = ppindex ? *ppindex : pindexDummy; + + bool accepted_header{m_chainman.AcceptBlockHeader(block, state, m_params, &pindex)}; + CheckBlockIndex(); + + if (!accepted_header) + return false; + + // Try to process all requested blocks that we don't have, but only + // process an unrequested block if it's new and has enough work to + // advance our tip, and isn't too many blocks ahead. + bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA; + bool fHasMoreOrSameWork = (m_chain.Tip() ? pindex->nChainWork >= m_chain.Tip()->nChainWork : true); + // Blocks that are too out-of-order needlessly limit the effectiveness of + // pruning, because pruning will not delete block files that contain any + // blocks which are too close in height to the tip. Apply this test + // regardless of whether pruning is enabled; it should generally be safe to + // not process unrequested blocks. + bool fTooFarAhead{pindex->nHeight > m_chain.Height() + int(MIN_BLOCKS_TO_KEEP)}; + + // TODO: Decouple this function from the block download logic by removing fRequested + // This requires some new chain data structure to efficiently look up if a + // block is in a chain leading to a candidate for best tip, despite not + // being such a candidate itself. + // Note that this would break the getblockfrompeer RPC + + // TODO: deal better with return value and error conditions for duplicate + // and unrequested blocks. + if (fAlreadyHave) return true; + if (!fRequested) { // If we didn't ask for it: + if (pindex->nTx != 0) return true; // This is a previously-processed block that was pruned + if (!fHasMoreOrSameWork) return true; // Don't process less-work chains + if (fTooFarAhead) return true; // Block height is too high + + // Protect against DoS attacks from low-work chains. + // If our tip is behind, a peer could try to send us + // low-work blocks on a fake chain that we would never + // request; don't process these. + if (pindex->nChainWork < nMinimumChainWork) return true; + } + + if (!CheckBlock(block, state, m_params.GetConsensus()) || + !ContextualCheckBlock(block, state, m_params.GetConsensus(), pindex->pprev)) { + if (state.IsInvalid() && state.GetResult() != BlockValidationResult::BLOCK_MUTATED) { + pindex->nStatus |= BLOCK_FAILED_VALID; + m_blockman.m_dirty_blockindex.insert(pindex); + } + return error("%s: %s", __func__, state.ToString()); + } + + // Header is valid/has work, merkle tree and segwit merkle tree are good...RELAY NOW + // (but if it does not build on our best tip, let the SendMessages loop relay it) + if (!IsInitialBlockDownload() && m_chain.Tip() == pindex->pprev) + GetMainSignals().NewPoWValidBlock(pindex, pblock); + + // Write block to history file + if (fNewBlock) *fNewBlock = true; + try { + FlatFilePos blockPos{m_blockman.SaveBlockToDisk(block, pindex->nHeight, m_chain, m_params, dbp)}; + if (blockPos.IsNull()) { + state.Error(strprintf("%s: Failed to find position to write new block to disk", __func__)); + return false; + } + ReceivedBlockTransactions(block, pindex, blockPos); + } catch (const std::runtime_error& e) { + return AbortNode(state, std::string("System error: ") + e.what()); + } + + FlushStateToDisk(state, FlushStateMode::NONE); + + CheckBlockIndex(); + + return true; +} + +bool ChainstateManager::ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock>& block, bool force_processing, bool* new_block) +{ + AssertLockNotHeld(cs_main); + + { + CBlockIndex *pindex = nullptr; + if (new_block) *new_block = false; + BlockValidationState state; + + // CheckBlock() does not support multi-threaded block validation because CBlock::fChecked can cause data race. + // Therefore, the following critical section must include the CheckBlock() call as well. + LOCK(cs_main); + + // Skipping AcceptBlock() for CheckBlock() failures means that we will never mark a block as invalid if + // CheckBlock() fails. This is protective against consensus failure if there are any unknown forms of block + // malleability that cause CheckBlock() to fail; see e.g. CVE-2012-2459 and + // https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-February/016697.html. Because CheckBlock() is + // not very expensive, the anti-DoS benefits of caching failure (of a definitely-invalid block) are not substantial. + bool ret = CheckBlock(*block, state, chainparams.GetConsensus()); + if (ret) { + // Store to disk + ret = ActiveChainstate().AcceptBlock(block, state, &pindex, force_processing, nullptr, new_block); + } + if (!ret) { + GetMainSignals().BlockChecked(*block, state); + return error("%s: AcceptBlock FAILED (%s)", __func__, state.ToString()); + } + } + + NotifyHeaderTip(ActiveChainstate()); + + BlockValidationState state; // Only used to report errors, not invalidity - ignore it + if (!ActiveChainstate().ActivateBestChain(state, block)) { + return error("%s: ActivateBestChain failed (%s)", __func__, state.ToString()); + } + + return true; +} + +MempoolAcceptResult ChainstateManager::ProcessTransaction(const CTransactionRef& tx, bool test_accept) +{ + AssertLockHeld(cs_main); + CChainState& active_chainstate = ActiveChainstate(); + if (!active_chainstate.GetMempool()) { + TxValidationState state; + state.Invalid(TxValidationResult::TX_NO_MEMPOOL, "no-mempool"); + return MempoolAcceptResult::Failure(state); + } + auto result = AcceptToMemoryPool(active_chainstate, tx, GetTime(), /*bypass_limits=*/ false, test_accept); + active_chainstate.GetMempool()->check(active_chainstate.CoinsTip(), active_chainstate.m_chain.Height() + 1); + return result; +} + +bool TestBlockValidity(BlockValidationState& state, + const CChainParams& chainparams, + CChainState& chainstate, + const CBlock& block, + CBlockIndex* pindexPrev, + bool fCheckPOW, + bool fCheckMerkleRoot) +{ + AssertLockHeld(cs_main); + assert(pindexPrev && pindexPrev == chainstate.m_chain.Tip()); + CCoinsViewCache viewNew(&chainstate.CoinsTip()); + uint256 block_hash(block.GetHash()); + CBlockIndex indexDummy(block); + indexDummy.pprev = pindexPrev; + indexDummy.nHeight = pindexPrev->nHeight + 1; + indexDummy.phashBlock = &block_hash; + + // NOTE: CheckBlockHeader is called by CheckBlock + if (!ContextualCheckBlockHeader(block, state, chainstate.m_blockman, chainparams, pindexPrev, GetAdjustedTime())) + return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__, state.ToString()); + if (!CheckBlock(block, state, chainparams.GetConsensus(), fCheckPOW, fCheckMerkleRoot)) + return error("%s: Consensus::CheckBlock: %s", __func__, state.ToString()); + if (!ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindexPrev)) + return error("%s: Consensus::ContextualCheckBlock: %s", __func__, state.ToString()); + if (!chainstate.ConnectBlock(block, state, &indexDummy, viewNew, true)) { + return false; + } + assert(state.IsValid()); + + return true; +} + +/* This function is called from the RPC code for pruneblockchain */ +void PruneBlockFilesManual(CChainState& active_chainstate, int nManualPruneHeight) +{ + BlockValidationState state; + if (!active_chainstate.FlushStateToDisk( + state, FlushStateMode::NONE, nManualPruneHeight)) { + LogPrintf("%s: failed to flush state (%s)\n", __func__, state.ToString()); + } +} + +void CChainState::LoadMempool(const ArgsManager& args) +{ + if (!m_mempool) return; + if (args.GetBoolArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) { + ::LoadMempool(*m_mempool, *this); + } + m_mempool->SetIsLoaded(!ShutdownRequested()); +} + +bool CChainState::LoadChainTip() +{ + AssertLockHeld(cs_main); + const CCoinsViewCache& coins_cache = CoinsTip(); + assert(!coins_cache.GetBestBlock().IsNull()); // Never called when the coins view is empty + const CBlockIndex* tip = m_chain.Tip(); + + if (tip && tip->GetBlockHash() == coins_cache.GetBestBlock()) { + return true; + } + + // Load pointer to end of best chain + CBlockIndex* pindex = m_blockman.LookupBlockIndex(coins_cache.GetBestBlock()); + if (!pindex) { + return false; + } + m_chain.SetTip(pindex); + PruneBlockIndexCandidates(); + + tip = m_chain.Tip(); + LogPrintf("Loaded best chain: hashBestChain=%s height=%d date=%s progress=%f\n", + tip->GetBlockHash().ToString(), + m_chain.Height(), + FormatISO8601DateTime(tip->GetBlockTime()), + GuessVerificationProgress(m_params.TxData(), tip)); + return true; +} + +CVerifyDB::CVerifyDB() +{ + uiInterface.ShowProgress(_("Verifying blocks…").translated, 0, false); +} + +CVerifyDB::~CVerifyDB() +{ + uiInterface.ShowProgress("", 100, false); +} + +bool CVerifyDB::VerifyDB( + CChainState& chainstate, + const Consensus::Params& consensus_params, + CCoinsView& coinsview, + int nCheckLevel, int nCheckDepth) +{ + AssertLockHeld(cs_main); + + if (chainstate.m_chain.Tip() == nullptr || chainstate.m_chain.Tip()->pprev == nullptr) { + return true; + } + + // Verify blocks in the best chain + if (nCheckDepth <= 0 || nCheckDepth > chainstate.m_chain.Height()) { + nCheckDepth = chainstate.m_chain.Height(); + } + nCheckLevel = std::max(0, std::min(4, nCheckLevel)); + LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel); + CCoinsViewCache coins(&coinsview); + CBlockIndex* pindex; + CBlockIndex* pindexFailure = nullptr; + int nGoodTransactions = 0; + BlockValidationState state; + int reportDone = 0; + LogPrintf("[0%%]..."); /* Continued */ + + const bool is_snapshot_cs{!chainstate.m_from_snapshot_blockhash}; + + for (pindex = chainstate.m_chain.Tip(); pindex && pindex->pprev; pindex = pindex->pprev) { + const int percentageDone = std::max(1, std::min(99, (int)(((double)(chainstate.m_chain.Height() - pindex->nHeight)) / (double)nCheckDepth * (nCheckLevel >= 4 ? 50 : 100)))); + if (reportDone < percentageDone / 10) { + // report every 10% step + LogPrintf("[%d%%]...", percentageDone); /* Continued */ + reportDone = percentageDone / 10; + } + uiInterface.ShowProgress(_("Verifying blocks…").translated, percentageDone, false); + if (pindex->nHeight <= chainstate.m_chain.Height() - nCheckDepth) { + break; + } + if ((fPruneMode || is_snapshot_cs) && !(pindex->nStatus & BLOCK_HAVE_DATA)) { + // If pruning or running under an assumeutxo snapshot, only go + // back as far as we have data. + LogPrintf("VerifyDB(): block verification stopping at height %d (pruning, no data)\n", pindex->nHeight); + break; + } + CBlock block; + // check level 0: read from disk + if (!ReadBlockFromDisk(block, pindex, consensus_params)) { + return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); + } + // check level 1: verify block validity + if (nCheckLevel >= 1 && !CheckBlock(block, state, consensus_params)) { + return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__, + pindex->nHeight, pindex->GetBlockHash().ToString(), state.ToString()); + } + // check level 2: verify undo validity + if (nCheckLevel >= 2 && pindex) { + CBlockUndo undo; + if (!pindex->GetUndoPos().IsNull()) { + if (!UndoReadFromDisk(undo, pindex)) { + return error("VerifyDB(): *** found bad undo data at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); + } + } + } + // check level 3: check for inconsistencies during memory-only disconnect of tip blocks + size_t curr_coins_usage = coins.DynamicMemoryUsage() + chainstate.CoinsTip().DynamicMemoryUsage(); + + if (nCheckLevel >= 3 && curr_coins_usage <= chainstate.m_coinstip_cache_size_bytes) { + assert(coins.GetBestBlock() == pindex->GetBlockHash()); + DisconnectResult res = chainstate.DisconnectBlock(block, pindex, coins); + if (res == DISCONNECT_FAILED) { + return error("VerifyDB(): *** irrecoverable inconsistency in block data at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); + } + if (res == DISCONNECT_UNCLEAN) { + nGoodTransactions = 0; + pindexFailure = pindex; + } else { + nGoodTransactions += block.vtx.size(); + } + } + if (ShutdownRequested()) return true; + } + if (pindexFailure) { + return error("VerifyDB(): *** coin database inconsistencies found (last %i blocks, %i good transactions before that)\n", chainstate.m_chain.Height() - pindexFailure->nHeight + 1, nGoodTransactions); + } + + // store block count as we move pindex at check level >= 4 + int block_count = chainstate.m_chain.Height() - pindex->nHeight; + + // check level 4: try reconnecting blocks + if (nCheckLevel >= 4) { + while (pindex != chainstate.m_chain.Tip()) { + const int percentageDone = std::max(1, std::min(99, 100 - (int)(((double)(chainstate.m_chain.Height() - pindex->nHeight)) / (double)nCheckDepth * 50))); + if (reportDone < percentageDone / 10) { + // report every 10% step + LogPrintf("[%d%%]...", percentageDone); /* Continued */ + reportDone = percentageDone / 10; + } + uiInterface.ShowProgress(_("Verifying blocks…").translated, percentageDone, false); + pindex = chainstate.m_chain.Next(pindex); + CBlock block; + if (!ReadBlockFromDisk(block, pindex, consensus_params)) + return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); + if (!chainstate.ConnectBlock(block, state, pindex, coins)) { + return error("VerifyDB(): *** found unconnectable block at %d, hash=%s (%s)", pindex->nHeight, pindex->GetBlockHash().ToString(), state.ToString()); + } + if (ShutdownRequested()) return true; + } + } + + LogPrintf("[DONE].\n"); + LogPrintf("No coin database inconsistencies in last %i blocks (%i transactions)\n", block_count, nGoodTransactions); + + return true; +} + +/** Apply the effects of a block on the utxo cache, ignoring that it may already have been applied. */ +bool CChainState::RollforwardBlock(const CBlockIndex* pindex, CCoinsViewCache& inputs) +{ + AssertLockHeld(cs_main); + // TODO: merge with ConnectBlock + CBlock block; + if (!ReadBlockFromDisk(block, pindex, m_params.GetConsensus())) { + return error("ReplayBlock(): ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); + } + + for (const CTransactionRef& tx : block.vtx) { + if (!tx->IsCoinBase()) { + for (const CTxIn &txin : tx->vin) { + inputs.SpendCoin(txin.prevout); + } + } + // Pass check = true as every addition may be an overwrite. + AddCoins(inputs, *tx, pindex->nHeight, true); + } + return true; +} + +bool CChainState::ReplayBlocks() +{ + LOCK(cs_main); + + CCoinsView& db = this->CoinsDB(); + CCoinsViewCache cache(&db); + + std::vector<uint256> hashHeads = db.GetHeadBlocks(); + if (hashHeads.empty()) return true; // We're already in a consistent state. + if (hashHeads.size() != 2) return error("ReplayBlocks(): unknown inconsistent state"); + + uiInterface.ShowProgress(_("Replaying blocks…").translated, 0, false); + LogPrintf("Replaying blocks\n"); + + const CBlockIndex* pindexOld = nullptr; // Old tip during the interrupted flush. + const CBlockIndex* pindexNew; // New tip during the interrupted flush. + const CBlockIndex* pindexFork = nullptr; // Latest block common to both the old and the new tip. + + if (m_blockman.m_block_index.count(hashHeads[0]) == 0) { + return error("ReplayBlocks(): reorganization to unknown block requested"); + } + pindexNew = &(m_blockman.m_block_index[hashHeads[0]]); + + if (!hashHeads[1].IsNull()) { // The old tip is allowed to be 0, indicating it's the first flush. + if (m_blockman.m_block_index.count(hashHeads[1]) == 0) { + return error("ReplayBlocks(): reorganization from unknown block requested"); + } + pindexOld = &(m_blockman.m_block_index[hashHeads[1]]); + pindexFork = LastCommonAncestor(pindexOld, pindexNew); + assert(pindexFork != nullptr); + } + + // Rollback along the old branch. + while (pindexOld != pindexFork) { + if (pindexOld->nHeight > 0) { // Never disconnect the genesis block. + CBlock block; + if (!ReadBlockFromDisk(block, pindexOld, m_params.GetConsensus())) { + return error("RollbackBlock(): ReadBlockFromDisk() failed at %d, hash=%s", pindexOld->nHeight, pindexOld->GetBlockHash().ToString()); + } + LogPrintf("Rolling back %s (%i)\n", pindexOld->GetBlockHash().ToString(), pindexOld->nHeight); + DisconnectResult res = DisconnectBlock(block, pindexOld, cache); + if (res == DISCONNECT_FAILED) { + return error("RollbackBlock(): DisconnectBlock failed at %d, hash=%s", pindexOld->nHeight, pindexOld->GetBlockHash().ToString()); + } + // If DISCONNECT_UNCLEAN is returned, it means a non-existing UTXO was deleted, or an existing UTXO was + // overwritten. It corresponds to cases where the block-to-be-disconnect never had all its operations + // applied to the UTXO set. However, as both writing a UTXO and deleting a UTXO are idempotent operations, + // the result is still a version of the UTXO set with the effects of that block undone. + } + pindexOld = pindexOld->pprev; + } + + // Roll forward from the forking point to the new tip. + int nForkHeight = pindexFork ? pindexFork->nHeight : 0; + for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight; ++nHeight) { + const CBlockIndex& pindex{*Assert(pindexNew->GetAncestor(nHeight))}; + + LogPrintf("Rolling forward %s (%i)\n", pindex.GetBlockHash().ToString(), nHeight); + uiInterface.ShowProgress(_("Replaying blocks…").translated, (int) ((nHeight - nForkHeight) * 100.0 / (pindexNew->nHeight - nForkHeight)) , false); + if (!RollforwardBlock(&pindex, cache)) return false; + } + + cache.SetBestBlock(pindexNew->GetBlockHash()); + cache.Flush(); + uiInterface.ShowProgress("", 100, false); + return true; +} + +bool CChainState::NeedsRedownload() const +{ + AssertLockHeld(cs_main); + + // At and above m_params.SegwitHeight, segwit consensus rules must be validated + CBlockIndex* block{m_chain.Tip()}; + + while (block != nullptr && DeploymentActiveAt(*block, m_params.GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) { + if (!(block->nStatus & BLOCK_OPT_WITNESS)) { + // block is insufficiently validated for a segwit client + return true; + } + block = block->pprev; + } + + return false; +} + +void CChainState::UnloadBlockIndex() +{ + AssertLockHeld(::cs_main); + nBlockSequenceId = 1; + setBlockIndexCandidates.clear(); +} + +bool ChainstateManager::LoadBlockIndex() +{ + AssertLockHeld(cs_main); + // Load block index from databases + bool needs_init = fReindex; + if (!fReindex) { + bool ret = m_blockman.LoadBlockIndexDB(); + if (!ret) return false; + + std::vector<CBlockIndex*> vSortedByHeight{m_blockman.GetAllBlockIndices()}; + std::sort(vSortedByHeight.begin(), vSortedByHeight.end(), + CBlockIndexHeightOnlyComparator()); + + // Find start of assumed-valid region. + int first_assumed_valid_height = std::numeric_limits<int>::max(); + + for (const CBlockIndex* block : vSortedByHeight) { + if (block->IsAssumedValid()) { + auto chainstates = GetAll(); + + // If we encounter an assumed-valid block index entry, ensure that we have + // one chainstate that tolerates assumed-valid entries and another that does + // not (i.e. the background validation chainstate), since assumed-valid + // entries should always be pending validation by a fully-validated chainstate. + auto any_chain = [&](auto fnc) { return std::any_of(chainstates.cbegin(), chainstates.cend(), fnc); }; + assert(any_chain([](auto chainstate) { return chainstate->reliesOnAssumedValid(); })); + assert(any_chain([](auto chainstate) { return !chainstate->reliesOnAssumedValid(); })); + + first_assumed_valid_height = block->nHeight; + break; + } + } + + for (CBlockIndex* pindex : vSortedByHeight) { + if (ShutdownRequested()) return false; + if (pindex->IsAssumedValid() || + (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && + (pindex->HaveTxsDownloaded() || pindex->pprev == nullptr))) { + + // Fill each chainstate's block candidate set. Only add assumed-valid + // blocks to the tip candidate set if the chainstate is allowed to rely on + // assumed-valid blocks. + // + // If all setBlockIndexCandidates contained the assumed-valid blocks, the + // background chainstate's ActivateBestChain() call would add assumed-valid + // blocks to the chain (based on how FindMostWorkChain() works). Obviously + // we don't want this since the purpose of the background validation chain + // is to validate assued-valid blocks. + // + // Note: This is considering all blocks whose height is greater or equal to + // the first assumed-valid block to be assumed-valid blocks, and excluding + // them from the background chainstate's setBlockIndexCandidates set. This + // does mean that some blocks which are not technically assumed-valid + // (later blocks on a fork beginning before the first assumed-valid block) + // might not get added to the background chainstate, but this is ok, + // because they will still be attached to the active chainstate if they + // actually contain more work. + // + // Instead of this height-based approach, an earlier attempt was made at + // detecting "holistically" whether the block index under consideration + // relied on an assumed-valid ancestor, but this proved to be too slow to + // be practical. + for (CChainState* chainstate : GetAll()) { + if (chainstate->reliesOnAssumedValid() || + pindex->nHeight < first_assumed_valid_height) { + chainstate->setBlockIndexCandidates.insert(pindex); + } + } + } + if (pindex->nStatus & BLOCK_FAILED_MASK && (!m_best_invalid || pindex->nChainWork > m_best_invalid->nChainWork)) { + m_best_invalid = pindex; + } + if (pindex->IsValid(BLOCK_VALID_TREE) && (m_best_header == nullptr || CBlockIndexWorkComparator()(m_best_header, pindex))) + m_best_header = pindex; + } + + needs_init = m_blockman.m_block_index.empty(); + } + + if (needs_init) { + // Everything here is for *new* reindex/DBs. Thus, though + // LoadBlockIndexDB may have set fReindex if we shut down + // mid-reindex previously, we don't check fReindex and + // instead only check it prior to LoadBlockIndexDB to set + // needs_init. + + LogPrintf("Initializing databases...\n"); + } + return true; +} + +bool CChainState::LoadGenesisBlock() +{ + LOCK(cs_main); + + // Check whether we're already initialized by checking for genesis in + // m_blockman.m_block_index. Note that we can't use m_chain here, since it is + // set based on the coins db, not the block index db, which is the only + // thing loaded at this point. + if (m_blockman.m_block_index.count(m_params.GenesisBlock().GetHash())) + return true; + + try { + const CBlock& block = m_params.GenesisBlock(); + FlatFilePos blockPos{m_blockman.SaveBlockToDisk(block, 0, m_chain, m_params, nullptr)}; + if (blockPos.IsNull()) { + return error("%s: writing genesis block to disk failed", __func__); + } + CBlockIndex* pindex = m_blockman.AddToBlockIndex(block, m_chainman.m_best_header); + ReceivedBlockTransactions(block, pindex, blockPos); + } catch (const std::runtime_error& e) { + return error("%s: failed to write genesis block: %s", __func__, e.what()); + } + + return true; +} + +void CChainState::LoadExternalBlockFile(FILE* fileIn, FlatFilePos* dbp) +{ + AssertLockNotHeld(m_chainstate_mutex); + // Map of disk positions for blocks with unknown parent (only used for reindex) + static std::multimap<uint256, FlatFilePos> mapBlocksUnknownParent; + int64_t nStart = GetTimeMillis(); + + int nLoaded = 0; + try { + // This takes over fileIn and calls fclose() on it in the CBufferedFile destructor + CBufferedFile blkdat(fileIn, 2*MAX_BLOCK_SERIALIZED_SIZE, MAX_BLOCK_SERIALIZED_SIZE+8, SER_DISK, CLIENT_VERSION); + uint64_t nRewind = blkdat.GetPos(); + while (!blkdat.eof()) { + if (ShutdownRequested()) return; + + blkdat.SetPos(nRewind); + nRewind++; // start one byte further next time, in case of failure + blkdat.SetLimit(); // remove former limit + unsigned int nSize = 0; + try { + // locate a header + unsigned char buf[CMessageHeader::MESSAGE_START_SIZE]; + blkdat.FindByte(m_params.MessageStart()[0]); + nRewind = blkdat.GetPos() + 1; + blkdat >> buf; + if (memcmp(buf, m_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE)) { + continue; + } + // read size + blkdat >> nSize; + if (nSize < 80 || nSize > MAX_BLOCK_SERIALIZED_SIZE) + continue; + } catch (const std::exception&) { + // no valid block header found; don't complain + break; + } + try { + // read block + uint64_t nBlockPos = blkdat.GetPos(); + if (dbp) + dbp->nPos = nBlockPos; + blkdat.SetLimit(nBlockPos + nSize); + std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>(); + CBlock& block = *pblock; + blkdat >> block; + nRewind = blkdat.GetPos(); + + uint256 hash = block.GetHash(); + { + LOCK(cs_main); + // detect out of order blocks, and store them for later + if (hash != m_params.GetConsensus().hashGenesisBlock && !m_blockman.LookupBlockIndex(block.hashPrevBlock)) { + LogPrint(BCLog::REINDEX, "%s: Out of order block %s, parent %s not known\n", __func__, hash.ToString(), + block.hashPrevBlock.ToString()); + if (dbp) + mapBlocksUnknownParent.insert(std::make_pair(block.hashPrevBlock, *dbp)); + continue; + } + + // process in case the block isn't known yet + const CBlockIndex* pindex = m_blockman.LookupBlockIndex(hash); + if (!pindex || (pindex->nStatus & BLOCK_HAVE_DATA) == 0) { + BlockValidationState state; + if (AcceptBlock(pblock, state, nullptr, true, dbp, nullptr)) { + nLoaded++; + } + if (state.IsError()) { + break; + } + } else if (hash != m_params.GetConsensus().hashGenesisBlock && pindex->nHeight % 1000 == 0) { + LogPrint(BCLog::REINDEX, "Block Import: already had block %s at height %d\n", hash.ToString(), pindex->nHeight); + } + } + + // Activate the genesis block so normal node progress can continue + if (hash == m_params.GetConsensus().hashGenesisBlock) { + BlockValidationState state; + if (!ActivateBestChain(state, nullptr)) { + break; + } + } + + NotifyHeaderTip(*this); + + // Recursively process earlier encountered successors of this block + std::deque<uint256> queue; + queue.push_back(hash); + while (!queue.empty()) { + uint256 head = queue.front(); + queue.pop_front(); + std::pair<std::multimap<uint256, FlatFilePos>::iterator, std::multimap<uint256, FlatFilePos>::iterator> range = mapBlocksUnknownParent.equal_range(head); + while (range.first != range.second) { + std::multimap<uint256, FlatFilePos>::iterator it = range.first; + std::shared_ptr<CBlock> pblockrecursive = std::make_shared<CBlock>(); + if (ReadBlockFromDisk(*pblockrecursive, it->second, m_params.GetConsensus())) { + LogPrint(BCLog::REINDEX, "%s: Processing out of order child %s of %s\n", __func__, pblockrecursive->GetHash().ToString(), + head.ToString()); + LOCK(cs_main); + BlockValidationState dummy; + if (AcceptBlock(pblockrecursive, dummy, nullptr, true, &it->second, nullptr)) { + nLoaded++; + queue.push_back(pblockrecursive->GetHash()); + } + } + range.first++; + mapBlocksUnknownParent.erase(it); + NotifyHeaderTip(*this); + } + } + } catch (const std::exception& e) { + LogPrintf("%s: Deserialize or I/O error - %s\n", __func__, e.what()); + } + } + } catch (const std::runtime_error& e) { + AbortNode(std::string("System error: ") + e.what()); + } + LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart); +} + +void CChainState::CheckBlockIndex() +{ + if (!fCheckBlockIndex) { + return; + } + + LOCK(cs_main); + + // During a reindex, we read the genesis block and call CheckBlockIndex before ActivateBestChain, + // so we have the genesis block in m_blockman.m_block_index but no active chain. (A few of the + // tests when iterating the block tree require that m_chain has been initialized.) + if (m_chain.Height() < 0) { + assert(m_blockman.m_block_index.size() <= 1); + return; + } + + // Build forward-pointing map of the entire block tree. + std::multimap<CBlockIndex*,CBlockIndex*> forward; + for (auto& [_, block_index] : m_blockman.m_block_index) { + forward.emplace(block_index.pprev, &block_index); + } + + assert(forward.size() == m_blockman.m_block_index.size()); + + std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeGenesis = forward.equal_range(nullptr); + CBlockIndex *pindex = rangeGenesis.first->second; + rangeGenesis.first++; + assert(rangeGenesis.first == rangeGenesis.second); // There is only one index entry with parent nullptr. + + // Iterate over the entire block tree, using depth-first search. + // Along the way, remember whether there are blocks on the path from genesis + // block being explored which are the first to have certain properties. + size_t nNodes = 0; + int nHeight = 0; + CBlockIndex* pindexFirstInvalid = nullptr; // Oldest ancestor of pindex which is invalid. + CBlockIndex* pindexFirstMissing = nullptr; // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA. + CBlockIndex* pindexFirstNeverProcessed = nullptr; // Oldest ancestor of pindex for which nTx == 0. + CBlockIndex* pindexFirstNotTreeValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not). + CBlockIndex* pindexFirstNotTransactionsValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not). + CBlockIndex* pindexFirstNotChainValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not). + CBlockIndex* pindexFirstNotScriptsValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not). + while (pindex != nullptr) { + nNodes++; + if (pindexFirstInvalid == nullptr && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex; + // Assumed-valid index entries will not have data since we haven't downloaded the + // full block yet. + if (pindexFirstMissing == nullptr && !(pindex->nStatus & BLOCK_HAVE_DATA) && !pindex->IsAssumedValid()) { + pindexFirstMissing = pindex; + } + if (pindexFirstNeverProcessed == nullptr && pindex->nTx == 0) pindexFirstNeverProcessed = pindex; + if (pindex->pprev != nullptr && pindexFirstNotTreeValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex; + + if (pindex->pprev != nullptr && !pindex->IsAssumedValid()) { + // Skip validity flag checks for BLOCK_ASSUMED_VALID index entries, since these + // *_VALID_MASK flags will not be present for index entries we are temporarily assuming + // valid. + if (pindexFirstNotTransactionsValid == nullptr && + (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) { + pindexFirstNotTransactionsValid = pindex; + } + + if (pindexFirstNotChainValid == nullptr && + (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) { + pindexFirstNotChainValid = pindex; + } + + if (pindexFirstNotScriptsValid == nullptr && + (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) { + pindexFirstNotScriptsValid = pindex; + } + } + + // Begin: actual consistency checks. + if (pindex->pprev == nullptr) { + // Genesis block checks. + assert(pindex->GetBlockHash() == m_params.GetConsensus().hashGenesisBlock); // Genesis block's hash must match. + assert(pindex == m_chain.Genesis()); // The current active chain's genesis block must be this block. + } + if (!pindex->HaveTxsDownloaded()) assert(pindex->nSequenceId <= 0); // nSequenceId can't be set positive for blocks that aren't linked (negative is used for preciousblock) + // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or not pruning has occurred). + // HAVE_DATA is only equivalent to nTx > 0 (or VALID_TRANSACTIONS) if no pruning has occurred. + // Unless these indexes are assumed valid and pending block download on a + // background chainstate. + if (!m_blockman.m_have_pruned && !pindex->IsAssumedValid()) { + // If we've never pruned, then HAVE_DATA should be equivalent to nTx > 0 + assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0)); + assert(pindexFirstMissing == pindexFirstNeverProcessed); + } else { + // If we have pruned, then we can only say that HAVE_DATA implies nTx > 0 + if (pindex->nStatus & BLOCK_HAVE_DATA) assert(pindex->nTx > 0); + } + if (pindex->nStatus & BLOCK_HAVE_UNDO) assert(pindex->nStatus & BLOCK_HAVE_DATA); + if (pindex->IsAssumedValid()) { + // Assumed-valid blocks should have some nTx value. + assert(pindex->nTx > 0); + // Assumed-valid blocks should connect to the main chain. + assert((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE); + } else { + // Otherwise there should only be an nTx value if we have + // actually seen a block's transactions. + assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0)); // This is pruning-independent. + } + // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to HaveTxsDownloaded(). + assert((pindexFirstNeverProcessed == nullptr) == pindex->HaveTxsDownloaded()); + assert((pindexFirstNotTransactionsValid == nullptr) == pindex->HaveTxsDownloaded()); + assert(pindex->nHeight == nHeight); // nHeight must be consistent. + assert(pindex->pprev == nullptr || pindex->nChainWork >= pindex->pprev->nChainWork); // For every block except the genesis block, the chainwork must be larger than the parent's. + assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight))); // The pskip pointer must point back for all but the first 2 blocks. + assert(pindexFirstNotTreeValid == nullptr); // All m_blockman.m_block_index entries must at least be TREE valid + if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) assert(pindexFirstNotTreeValid == nullptr); // TREE valid implies all parents are TREE valid + if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) assert(pindexFirstNotChainValid == nullptr); // CHAIN valid implies all parents are CHAIN valid + if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == nullptr); // SCRIPTS valid implies all parents are SCRIPTS valid + if (pindexFirstInvalid == nullptr) { + // Checks for not-invalid blocks. + assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents. + } + if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) && pindexFirstNeverProcessed == nullptr) { + if (pindexFirstInvalid == nullptr) { + const bool is_active = this == &m_chainman.ActiveChainstate(); + + // If this block sorts at least as good as the current tip and + // is valid and we have all data for its parents, it must be in + // setBlockIndexCandidates. m_chain.Tip() must also be there + // even if some data has been pruned. + // + // Don't perform this check for the background chainstate since + // its setBlockIndexCandidates shouldn't have some entries (i.e. those past the + // snapshot block) which do exist in the block index for the active chainstate. + if (is_active && (pindexFirstMissing == nullptr || pindex == m_chain.Tip())) { + assert(setBlockIndexCandidates.count(pindex)); + } + // If some parent is missing, then it could be that this block was in + // setBlockIndexCandidates but had to be removed because of the missing data. + // In this case it must be in m_blocks_unlinked -- see test below. + } + } else { // If this block sorts worse than the current tip or some ancestor's block has never been seen, it cannot be in setBlockIndexCandidates. + assert(setBlockIndexCandidates.count(pindex) == 0); + } + // Check whether this block is in m_blocks_unlinked. + std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeUnlinked = m_blockman.m_blocks_unlinked.equal_range(pindex->pprev); + bool foundInUnlinked = false; + while (rangeUnlinked.first != rangeUnlinked.second) { + assert(rangeUnlinked.first->first == pindex->pprev); + if (rangeUnlinked.first->second == pindex) { + foundInUnlinked = true; + break; + } + rangeUnlinked.first++; + } + if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed != nullptr && pindexFirstInvalid == nullptr) { + // If this block has block data available, some parent was never received, and has no invalid parents, it must be in m_blocks_unlinked. + assert(foundInUnlinked); + } + if (!(pindex->nStatus & BLOCK_HAVE_DATA)) assert(!foundInUnlinked); // Can't be in m_blocks_unlinked if we don't HAVE_DATA + if (pindexFirstMissing == nullptr) assert(!foundInUnlinked); // We aren't missing data for any parent -- cannot be in m_blocks_unlinked. + if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == nullptr && pindexFirstMissing != nullptr) { + // We HAVE_DATA for this block, have received data for all parents at some point, but we're currently missing data for some parent. + assert(m_blockman.m_have_pruned); // We must have pruned. + // This block may have entered m_blocks_unlinked if: + // - it has a descendant that at some point had more work than the + // tip, and + // - we tried switching to that descendant but were missing + // data for some intermediate block between m_chain and the + // tip. + // So if this block is itself better than m_chain.Tip() and it wasn't in + // setBlockIndexCandidates, then it must be in m_blocks_unlinked. + if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) && setBlockIndexCandidates.count(pindex) == 0) { + if (pindexFirstInvalid == nullptr) { + assert(foundInUnlinked); + } + } + } + // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash()); // Perhaps too slow + // End: actual consistency checks. + + // Try descending into the first subnode. + std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> range = forward.equal_range(pindex); + if (range.first != range.second) { + // A subnode was found. + pindex = range.first->second; + nHeight++; + continue; + } + // This is a leaf node. + // Move upwards until we reach a node of which we have not yet visited the last child. + while (pindex) { + // We are going to either move to a parent or a sibling of pindex. + // If pindex was the first with a certain property, unset the corresponding variable. + if (pindex == pindexFirstInvalid) pindexFirstInvalid = nullptr; + if (pindex == pindexFirstMissing) pindexFirstMissing = nullptr; + if (pindex == pindexFirstNeverProcessed) pindexFirstNeverProcessed = nullptr; + if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = nullptr; + if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = nullptr; + if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = nullptr; + if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = nullptr; + // Find our parent. + CBlockIndex* pindexPar = pindex->pprev; + // Find which child we just visited. + std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangePar = forward.equal_range(pindexPar); + while (rangePar.first->second != pindex) { + assert(rangePar.first != rangePar.second); // Our parent must have at least the node we're coming from as child. + rangePar.first++; + } + // Proceed to the next one. + rangePar.first++; + if (rangePar.first != rangePar.second) { + // Move to the sibling. + pindex = rangePar.first->second; + break; + } else { + // Move up further. + pindex = pindexPar; + nHeight--; + continue; + } + } + } + + // Check that we actually traversed the entire map. + assert(nNodes == forward.size()); +} + +std::string CChainState::ToString() +{ + AssertLockHeld(::cs_main); + CBlockIndex* tip = m_chain.Tip(); + return strprintf("Chainstate [%s] @ height %d (%s)", + m_from_snapshot_blockhash ? "snapshot" : "ibd", + tip ? tip->nHeight : -1, tip ? tip->GetBlockHash().ToString() : "null"); +} + +bool CChainState::ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size) +{ + AssertLockHeld(::cs_main); + if (coinstip_size == m_coinstip_cache_size_bytes && + coinsdb_size == m_coinsdb_cache_size_bytes) { + // Cache sizes are unchanged, no need to continue. + return true; + } + size_t old_coinstip_size = m_coinstip_cache_size_bytes; + m_coinstip_cache_size_bytes = coinstip_size; + m_coinsdb_cache_size_bytes = coinsdb_size; + CoinsDB().ResizeCache(coinsdb_size); + + LogPrintf("[%s] resized coinsdb cache to %.1f MiB\n", + this->ToString(), coinsdb_size * (1.0 / 1024 / 1024)); + LogPrintf("[%s] resized coinstip cache to %.1f MiB\n", + this->ToString(), coinstip_size * (1.0 / 1024 / 1024)); + + BlockValidationState state; + bool ret; + + if (coinstip_size > old_coinstip_size) { + // Likely no need to flush if cache sizes have grown. + ret = FlushStateToDisk(state, FlushStateMode::IF_NEEDED); + } else { + // Otherwise, flush state to disk and deallocate the in-memory coins map. + ret = FlushStateToDisk(state, FlushStateMode::ALWAYS); + CoinsTip().ReallocateCache(); + } + return ret; +} + +static const uint64_t MEMPOOL_DUMP_VERSION = 1; + +bool LoadMempool(CTxMemPool& pool, CChainState& active_chainstate, FopenFn mockable_fopen_function) +{ + int64_t nExpiryTimeout = gArgs.GetIntArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60; + FILE* filestr{mockable_fopen_function(gArgs.GetDataDirNet() / "mempool.dat", "rb")}; + CAutoFile file(filestr, SER_DISK, CLIENT_VERSION); + if (file.IsNull()) { + LogPrintf("Failed to open mempool file from disk. Continuing anyway.\n"); + return false; + } + + int64_t count = 0; + int64_t expired = 0; + int64_t failed = 0; + int64_t already_there = 0; + int64_t unbroadcast = 0; + int64_t nNow = GetTime(); + + try { + uint64_t version; + file >> version; + if (version != MEMPOOL_DUMP_VERSION) { + return false; + } + uint64_t num; + file >> num; + while (num) { + --num; + CTransactionRef tx; + int64_t nTime; + int64_t nFeeDelta; + file >> tx; + file >> nTime; + file >> nFeeDelta; + + CAmount amountdelta = nFeeDelta; + if (amountdelta) { + pool.PrioritiseTransaction(tx->GetHash(), amountdelta); + } + if (nTime > nNow - nExpiryTimeout) { + LOCK(cs_main); + const auto& accepted = AcceptToMemoryPool(active_chainstate, tx, nTime, /*bypass_limits=*/false, /*test_accept=*/false); + if (accepted.m_result_type == MempoolAcceptResult::ResultType::VALID) { + ++count; + } else { + // mempool may contain the transaction already, e.g. from + // wallet(s) having loaded it while we were processing + // mempool transactions; consider these as valid, instead of + // failed, but mark them as 'already there' + if (pool.exists(GenTxid::Txid(tx->GetHash()))) { + ++already_there; + } else { + ++failed; + } + } + } else { + ++expired; + } + if (ShutdownRequested()) + return false; + } + std::map<uint256, CAmount> mapDeltas; + file >> mapDeltas; + + for (const auto& i : mapDeltas) { + pool.PrioritiseTransaction(i.first, i.second); + } + + std::set<uint256> unbroadcast_txids; + file >> unbroadcast_txids; + unbroadcast = unbroadcast_txids.size(); + for (const auto& txid : unbroadcast_txids) { + // Ensure transactions were accepted to mempool then add to + // unbroadcast set. + if (pool.get(txid) != nullptr) pool.AddUnbroadcastTx(txid); + } + } catch (const std::exception& e) { + LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing anyway.\n", e.what()); + return false; + } + + LogPrintf("Imported mempool transactions from disk: %i succeeded, %i failed, %i expired, %i already there, %i waiting for initial broadcast\n", count, failed, expired, already_there, unbroadcast); + return true; +} + +bool DumpMempool(const CTxMemPool& pool, FopenFn mockable_fopen_function, bool skip_file_commit) +{ + int64_t start = GetTimeMicros(); + + std::map<uint256, CAmount> mapDeltas; + std::vector<TxMempoolInfo> vinfo; + std::set<uint256> unbroadcast_txids; + + static Mutex dump_mutex; + LOCK(dump_mutex); + + { + LOCK(pool.cs); + for (const auto &i : pool.mapDeltas) { + mapDeltas[i.first] = i.second; + } + vinfo = pool.infoAll(); + unbroadcast_txids = pool.GetUnbroadcastTxs(); + } + + int64_t mid = GetTimeMicros(); + + try { + FILE* filestr{mockable_fopen_function(gArgs.GetDataDirNet() / "mempool.dat.new", "wb")}; + if (!filestr) { + return false; + } + + CAutoFile file(filestr, SER_DISK, CLIENT_VERSION); + + uint64_t version = MEMPOOL_DUMP_VERSION; + file << version; + + file << (uint64_t)vinfo.size(); + for (const auto& i : vinfo) { + file << *(i.tx); + file << int64_t{count_seconds(i.m_time)}; + file << int64_t{i.nFeeDelta}; + mapDeltas.erase(i.tx->GetHash()); + } + + file << mapDeltas; + + LogPrintf("Writing %d unbroadcast transactions to disk.\n", unbroadcast_txids.size()); + file << unbroadcast_txids; + + if (!skip_file_commit && !FileCommit(file.Get())) + throw std::runtime_error("FileCommit failed"); + file.fclose(); + if (!RenameOver(gArgs.GetDataDirNet() / "mempool.dat.new", gArgs.GetDataDirNet() / "mempool.dat")) { + throw std::runtime_error("Rename failed"); + } + int64_t last = GetTimeMicros(); + LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n", (mid-start)*MICRO, (last-mid)*MICRO); + } catch (const std::exception& e) { + LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what()); + return false; + } + return true; +} + +//! Guess how far we are in the verification process at the given block index +//! require cs_main if pindex has not been validated yet (because nChainTx might be unset) +double GuessVerificationProgress(const ChainTxData& data, const CBlockIndex *pindex) { + if (pindex == nullptr) + return 0.0; + + int64_t nNow = time(nullptr); + + double fTxTotal; + + if (pindex->nChainTx <= data.nTxCount) { + fTxTotal = data.nTxCount + (nNow - data.nTime) * data.dTxRate; + } else { + fTxTotal = pindex->nChainTx + (nNow - pindex->GetBlockTime()) * data.dTxRate; + } + + return std::min<double>(pindex->nChainTx / fTxTotal, 1.0); +} + +std::optional<uint256> ChainstateManager::SnapshotBlockhash() const +{ + LOCK(::cs_main); + if (m_active_chainstate && m_active_chainstate->m_from_snapshot_blockhash) { + // If a snapshot chainstate exists, it will always be our active. + return m_active_chainstate->m_from_snapshot_blockhash; + } + return std::nullopt; +} + +std::vector<CChainState*> ChainstateManager::GetAll() +{ + LOCK(::cs_main); + std::vector<CChainState*> out; + + if (!IsSnapshotValidated() && m_ibd_chainstate) { + out.push_back(m_ibd_chainstate.get()); + } + + if (m_snapshot_chainstate) { + out.push_back(m_snapshot_chainstate.get()); + } + + return out; +} + +CChainState& ChainstateManager::InitializeChainstate( + CTxMemPool* mempool, const std::optional<uint256>& snapshot_blockhash) +{ + AssertLockHeld(::cs_main); + bool is_snapshot = snapshot_blockhash.has_value(); + std::unique_ptr<CChainState>& to_modify = + is_snapshot ? m_snapshot_chainstate : m_ibd_chainstate; + + if (to_modify) { + throw std::logic_error("should not be overwriting a chainstate"); + } + to_modify.reset(new CChainState(mempool, m_blockman, *this, snapshot_blockhash)); + + // Snapshot chainstates and initial IBD chaintates always become active. + if (is_snapshot || (!is_snapshot && !m_active_chainstate)) { + LogPrintf("Switching active chainstate to %s\n", to_modify->ToString()); + m_active_chainstate = to_modify.get(); + } else { + throw std::logic_error("unexpected chainstate activation"); + } + + return *to_modify; +} + +const AssumeutxoData* ExpectedAssumeutxo( + const int height, const CChainParams& chainparams) +{ + const MapAssumeutxo& valid_assumeutxos_map = chainparams.Assumeutxo(); + const auto assumeutxo_found = valid_assumeutxos_map.find(height); + + if (assumeutxo_found != valid_assumeutxos_map.end()) { + return &assumeutxo_found->second; + } + return nullptr; +} + +bool ChainstateManager::ActivateSnapshot( + CAutoFile& coins_file, + const SnapshotMetadata& metadata, + bool in_memory) +{ + uint256 base_blockhash = metadata.m_base_blockhash; + + if (this->SnapshotBlockhash()) { + LogPrintf("[snapshot] can't activate a snapshot-based chainstate more than once\n"); + return false; + } + + int64_t current_coinsdb_cache_size{0}; + int64_t current_coinstip_cache_size{0}; + + // Cache percentages to allocate to each chainstate. + // + // These particular percentages don't matter so much since they will only be + // relevant during snapshot activation; caches are rebalanced at the conclusion of + // this function. We want to give (essentially) all available cache capacity to the + // snapshot to aid the bulk load later in this function. + static constexpr double IBD_CACHE_PERC = 0.01; + static constexpr double SNAPSHOT_CACHE_PERC = 0.99; + + { + LOCK(::cs_main); + // Resize the coins caches to ensure we're not exceeding memory limits. + // + // Allocate the majority of the cache to the incoming snapshot chainstate, since + // (optimistically) getting to its tip will be the top priority. We'll need to call + // `MaybeRebalanceCaches()` once we're done with this function to ensure + // the right allocation (including the possibility that no snapshot was activated + // and that we should restore the active chainstate caches to their original size). + // + current_coinsdb_cache_size = this->ActiveChainstate().m_coinsdb_cache_size_bytes; + current_coinstip_cache_size = this->ActiveChainstate().m_coinstip_cache_size_bytes; + + // Temporarily resize the active coins cache to make room for the newly-created + // snapshot chain. + this->ActiveChainstate().ResizeCoinsCaches( + static_cast<size_t>(current_coinstip_cache_size * IBD_CACHE_PERC), + static_cast<size_t>(current_coinsdb_cache_size * IBD_CACHE_PERC)); + } + + auto snapshot_chainstate = WITH_LOCK(::cs_main, + return std::make_unique<CChainState>( + /*mempool=*/nullptr, m_blockman, *this, base_blockhash)); + + { + LOCK(::cs_main); + snapshot_chainstate->InitCoinsDB( + static_cast<size_t>(current_coinsdb_cache_size * SNAPSHOT_CACHE_PERC), + in_memory, false, "chainstate"); + snapshot_chainstate->InitCoinsCache( + static_cast<size_t>(current_coinstip_cache_size * SNAPSHOT_CACHE_PERC)); + } + + const bool snapshot_ok = this->PopulateAndValidateSnapshot( + *snapshot_chainstate, coins_file, metadata); + + if (!snapshot_ok) { + WITH_LOCK(::cs_main, this->MaybeRebalanceCaches()); + return false; + } + + { + LOCK(::cs_main); + assert(!m_snapshot_chainstate); + m_snapshot_chainstate.swap(snapshot_chainstate); + const bool chaintip_loaded = m_snapshot_chainstate->LoadChainTip(); + assert(chaintip_loaded); + + m_active_chainstate = m_snapshot_chainstate.get(); + + LogPrintf("[snapshot] successfully activated snapshot %s\n", base_blockhash.ToString()); + LogPrintf("[snapshot] (%.2f MB)\n", + m_snapshot_chainstate->CoinsTip().DynamicMemoryUsage() / (1000 * 1000)); + + this->MaybeRebalanceCaches(); + } + return true; +} + +static void FlushSnapshotToDisk(CCoinsViewCache& coins_cache, bool snapshot_loaded) +{ + LOG_TIME_MILLIS_WITH_CATEGORY_MSG_ONCE( + strprintf("%s (%.2f MB)", + snapshot_loaded ? "saving snapshot chainstate" : "flushing coins cache", + coins_cache.DynamicMemoryUsage() / (1000 * 1000)), + BCLog::LogFlags::ALL); + + coins_cache.Flush(); +} + +bool ChainstateManager::PopulateAndValidateSnapshot( + CChainState& snapshot_chainstate, + CAutoFile& coins_file, + const SnapshotMetadata& metadata) +{ + // It's okay to release cs_main before we're done using `coins_cache` because we know + // that nothing else will be referencing the newly created snapshot_chainstate yet. + CCoinsViewCache& coins_cache = *WITH_LOCK(::cs_main, return &snapshot_chainstate.CoinsTip()); + + uint256 base_blockhash = metadata.m_base_blockhash; + + CBlockIndex* snapshot_start_block = WITH_LOCK(::cs_main, return m_blockman.LookupBlockIndex(base_blockhash)); + + if (!snapshot_start_block) { + // Needed for GetUTXOStats and ExpectedAssumeutxo to determine the height and to avoid a crash when base_blockhash.IsNull() + LogPrintf("[snapshot] Did not find snapshot start blockheader %s\n", + base_blockhash.ToString()); + return false; + } + + int base_height = snapshot_start_block->nHeight; + auto maybe_au_data = ExpectedAssumeutxo(base_height, ::Params()); + + if (!maybe_au_data) { + LogPrintf("[snapshot] assumeutxo height in snapshot metadata not recognized " /* Continued */ + "(%d) - refusing to load snapshot\n", base_height); + return false; + } + + const AssumeutxoData& au_data = *maybe_au_data; + + COutPoint outpoint; + Coin coin; + const uint64_t coins_count = metadata.m_coins_count; + uint64_t coins_left = metadata.m_coins_count; + + LogPrintf("[snapshot] loading coins from snapshot %s\n", base_blockhash.ToString()); + int64_t coins_processed{0}; + + while (coins_left > 0) { + try { + coins_file >> outpoint; + coins_file >> coin; + } catch (const std::ios_base::failure&) { + LogPrintf("[snapshot] bad snapshot format or truncated snapshot after deserializing %d coins\n", + coins_count - coins_left); + return false; + } + if (coin.nHeight > base_height || + outpoint.n >= std::numeric_limits<decltype(outpoint.n)>::max() // Avoid integer wrap-around in coinstats.cpp:ApplyHash + ) { + LogPrintf("[snapshot] bad snapshot data after deserializing %d coins\n", + coins_count - coins_left); + return false; + } + + coins_cache.EmplaceCoinInternalDANGER(std::move(outpoint), std::move(coin)); + + --coins_left; + ++coins_processed; + + if (coins_processed % 1000000 == 0) { + LogPrintf("[snapshot] %d coins loaded (%.2f%%, %.2f MB)\n", + coins_processed, + static_cast<float>(coins_processed) * 100 / static_cast<float>(coins_count), + coins_cache.DynamicMemoryUsage() / (1000 * 1000)); + } + + // Batch write and flush (if we need to) every so often. + // + // If our average Coin size is roughly 41 bytes, checking every 120,000 coins + // means <5MB of memory imprecision. + if (coins_processed % 120000 == 0) { + if (ShutdownRequested()) { + return false; + } + + const auto snapshot_cache_state = WITH_LOCK(::cs_main, + return snapshot_chainstate.GetCoinsCacheSizeState()); + + if (snapshot_cache_state >= CoinsCacheSizeState::CRITICAL) { + // This is a hack - we don't know what the actual best block is, but that + // doesn't matter for the purposes of flushing the cache here. We'll set this + // to its correct value (`base_blockhash`) below after the coins are loaded. + coins_cache.SetBestBlock(GetRandHash()); + + // No need to acquire cs_main since this chainstate isn't being used yet. + FlushSnapshotToDisk(coins_cache, /*snapshot_loaded=*/false); + } + } + } + + // Important that we set this. This and the coins_cache accesses above are + // sort of a layer violation, but either we reach into the innards of + // CCoinsViewCache here or we have to invert some of the CChainState to + // embed them in a snapshot-activation-specific CCoinsViewCache bulk load + // method. + coins_cache.SetBestBlock(base_blockhash); + + bool out_of_coins{false}; + try { + coins_file >> outpoint; + } catch (const std::ios_base::failure&) { + // We expect an exception since we should be out of coins. + out_of_coins = true; + } + if (!out_of_coins) { + LogPrintf("[snapshot] bad snapshot - coins left over after deserializing %d coins\n", + coins_count); + return false; + } + + LogPrintf("[snapshot] loaded %d (%.2f MB) coins from snapshot %s\n", + coins_count, + coins_cache.DynamicMemoryUsage() / (1000 * 1000), + base_blockhash.ToString()); + + // No need to acquire cs_main since this chainstate isn't being used yet. + FlushSnapshotToDisk(coins_cache, /*snapshot_loaded=*/true); + + assert(coins_cache.GetBestBlock() == base_blockhash); + + CCoinsStats stats{CoinStatsHashType::HASH_SERIALIZED}; + auto breakpoint_fnc = [] { /* TODO insert breakpoint here? */ }; + + // As above, okay to immediately release cs_main here since no other context knows + // about the snapshot_chainstate. + CCoinsViewDB* snapshot_coinsdb = WITH_LOCK(::cs_main, return &snapshot_chainstate.CoinsDB()); + + if (!GetUTXOStats(snapshot_coinsdb, m_blockman, stats, breakpoint_fnc)) { + LogPrintf("[snapshot] failed to generate coins stats\n"); + return false; + } + + // Assert that the deserialized chainstate contents match the expected assumeutxo value. + if (AssumeutxoHash{stats.hashSerialized} != au_data.hash_serialized) { + LogPrintf("[snapshot] bad snapshot content hash: expected %s, got %s\n", + au_data.hash_serialized.ToString(), stats.hashSerialized.ToString()); + return false; + } + + snapshot_chainstate.m_chain.SetTip(snapshot_start_block); + + // The remainder of this function requires modifying data protected by cs_main. + LOCK(::cs_main); + + // Fake various pieces of CBlockIndex state: + CBlockIndex* index = nullptr; + + // Don't make any modifications to the genesis block. + // This is especially important because we don't want to erroneously + // apply BLOCK_ASSUMED_VALID to genesis, which would happen if we didn't skip + // it here (since it apparently isn't BLOCK_VALID_SCRIPTS). + constexpr int AFTER_GENESIS_START{1}; + + for (int i = AFTER_GENESIS_START; i <= snapshot_chainstate.m_chain.Height(); ++i) { + index = snapshot_chainstate.m_chain[i]; + + // Fake nTx so that LoadBlockIndex() loads assumed-valid CBlockIndex + // entries (among other things) + if (!index->nTx) { + index->nTx = 1; + } + // Fake nChainTx so that GuessVerificationProgress reports accurately + index->nChainTx = index->pprev->nChainTx + index->nTx; + + // Mark unvalidated block index entries beneath the snapshot base block as assumed-valid. + if (!index->IsValid(BLOCK_VALID_SCRIPTS)) { + // This flag will be removed once the block is fully validated by a + // background chainstate. + index->nStatus |= BLOCK_ASSUMED_VALID; + } + + // Fake BLOCK_OPT_WITNESS so that CChainState::NeedsRedownload() + // won't ask to rewind the entire assumed-valid chain on startup. + if (DeploymentActiveAt(*index, ::Params().GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) { + index->nStatus |= BLOCK_OPT_WITNESS; + } + + m_blockman.m_dirty_blockindex.insert(index); + // Changes to the block index will be flushed to disk after this call + // returns in `ActivateSnapshot()`, when `MaybeRebalanceCaches()` is + // called, since we've added a snapshot chainstate and therefore will + // have to downsize the IBD chainstate, which will result in a call to + // `FlushStateToDisk(ALWAYS)`. + } + + assert(index); + index->nChainTx = au_data.nChainTx; + snapshot_chainstate.setBlockIndexCandidates.insert(snapshot_start_block); + + LogPrintf("[snapshot] validated snapshot (%.2f MB)\n", + coins_cache.DynamicMemoryUsage() / (1000 * 1000)); + return true; +} + +CChainState& ChainstateManager::ActiveChainstate() const +{ + LOCK(::cs_main); + assert(m_active_chainstate); + return *m_active_chainstate; +} + +bool ChainstateManager::IsSnapshotActive() const +{ + LOCK(::cs_main); + return m_snapshot_chainstate && m_active_chainstate == m_snapshot_chainstate.get(); +} + +void ChainstateManager::MaybeRebalanceCaches() +{ + AssertLockHeld(::cs_main); + if (m_ibd_chainstate && !m_snapshot_chainstate) { + LogPrintf("[snapshot] allocating all cache to the IBD chainstate\n"); + // Allocate everything to the IBD chainstate. + m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache, m_total_coinsdb_cache); + } + else if (m_snapshot_chainstate && !m_ibd_chainstate) { + LogPrintf("[snapshot] allocating all cache to the snapshot chainstate\n"); + // Allocate everything to the snapshot chainstate. + m_snapshot_chainstate->ResizeCoinsCaches(m_total_coinstip_cache, m_total_coinsdb_cache); + } + else if (m_ibd_chainstate && m_snapshot_chainstate) { + // If both chainstates exist, determine who needs more cache based on IBD status. + // + // Note: shrink caches first so that we don't inadvertently overwhelm available memory. + if (m_snapshot_chainstate->IsInitialBlockDownload()) { + m_ibd_chainstate->ResizeCoinsCaches( + m_total_coinstip_cache * 0.05, m_total_coinsdb_cache * 0.05); + m_snapshot_chainstate->ResizeCoinsCaches( + m_total_coinstip_cache * 0.95, m_total_coinsdb_cache * 0.95); + } else { + m_snapshot_chainstate->ResizeCoinsCaches( + m_total_coinstip_cache * 0.05, m_total_coinsdb_cache * 0.05); + m_ibd_chainstate->ResizeCoinsCaches( + m_total_coinstip_cache * 0.95, m_total_coinsdb_cache * 0.95); + } + } +} + +ChainstateManager::~ChainstateManager() +{ + LOCK(::cs_main); + + // TODO: The version bits cache and warning cache should probably become + // non-globals + g_versionbitscache.Clear(); + for (auto& i : warningcache) { + i.clear(); + } +} |