src/miner.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2014 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include "miner.h"
   7
   8 #include "amount.h"
   9 #include "chain.h"
  10 #include "chainparams.h"
  11 #include "coins.h"
  12 #include "consensus/consensus.h"
  13 #include "consensus/merkle.h"
  14 #include "consensus/validation.h"
  15 #include "hash.h"
  16 #include "main.h"
  17 #include "net.h"
  18 #include "policy/policy.h"
  19 #include "pow.h"
  20 #include "primitives/transaction.h"
  21 #include "script/standard.h"
  22 #include "timedata.h"
  23 #include "txmempool.h"
  24 #include "util.h"
  25 #include "utilmoneystr.h"
  26 #include "validationinterface.h"
  27
  28 #include <boost/thread.hpp>
  29 #include <boost/tuple/tuple.hpp>
  30
  31 using namespace std;
  32
  33 //////////////////////////////////////////////////////////////////////////////
  34 //
  35 // BitcoinMiner
  36 //
  37
  38 //
  39 // Unconfirmed transactions in the memory pool often depend on other
  40 // transactions in the memory pool. When we select transactions from the
  41 // pool, we select by highest priority or fee rate, so we might consider
  42 // transactions that depend on transactions that aren't yet in the block.
  43 // The COrphan class keeps track of these 'temporary orphans' while
  44 // CreateBlock is figuring out which transactions to include.
  45 //
  46 class COrphan
  47 {
  48 public:
  49     const CTransaction* ptx;
  50     set<uint256> setDependsOn;
  51     CFeeRate feeRate;
  52     double dPriority;
  53
  54     COrphan(const CTransaction* ptxIn) : ptx(ptxIn), feeRate(0), dPriority(0)
  55     {
  56     }
  57 };
  58
  59 uint64_t nLastBlockTx = 0;
  60 uint64_t nLastBlockSize = 0;
  61
  62 // We want to sort transactions by priority and fee rate, so:
  63 typedef boost::tuple<double, CFeeRate, const CTransaction*> TxPriority;
  64 class TxPriorityCompare
  65 {
  66     bool byFee;
  67
  68 public:
  69     TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
  70
  71     bool operator()(const TxPriority& a, const TxPriority& b)
  72     {
  73         if (byFee)
  74         {
  75             if (a.get<1>() == b.get<1>())
  76                 return a.get<0>() < b.get<0>();
  77             return a.get<1>() < b.get<1>();
  78         }
  79         else
  80         {
  81             if (a.get<0>() == b.get<0>())
  82                 return a.get<1>() < b.get<1>();
  83             return a.get<0>() < b.get<0>();
  84         }
  85     }
  86 };
  87
  88 int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
  89 {
  90     int64_t nOldTime = pblock->nTime;
  91     int64_t nNewTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
  92
  93     if (nOldTime < nNewTime)
  94         pblock->nTime = nNewTime;
  95
  96     // Updating time can change work required on testnet:
  97     if (consensusParams.fPowAllowMinDifficultyBlocks)
  98         pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams);
  99
 100     return nNewTime - nOldTime;
 101 }
 102
 103 CBlockTemplate* CreateNewBlock(const CChainParams& chainparams, const CScript& scriptPubKeyIn)
 104 {
 105     // Create new block
 106     auto_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
 107     if(!pblocktemplate.get())
 108         return NULL;
 109     CBlock *pblock = &pblocktemplate->block; // pointer for convenience
 110
 111     // -regtest only: allow overriding block.nVersion with
 112     // -blockversion=N to test forking scenarios
 113     if (chainparams.MineBlocksOnDemand())
 114         pblock->nVersion = GetArg("-blockversion", pblock->nVersion);
 115
 116     // Create coinbase tx
 117     CMutableTransaction txNew;
 118     txNew.vin.resize(1);
 119     txNew.vin[0].prevout.SetNull();
 120     txNew.vout.resize(1);
 121     txNew.vout[0].scriptPubKey = scriptPubKeyIn;
 122
 123     // Add dummy coinbase tx as first transaction
 124     pblock->vtx.push_back(CTransaction());
 125     pblocktemplate->vTxFees.push_back(-1); // updated at end
 126     pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 127
 128     // Largest block you're willing to create:
 129     unsigned int nBlockMaxSize = GetArg("-blockmaxsize", DEFAULT_BLOCK_MAX_SIZE);
 130     // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
 131     nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));
 132
 133     // How much of the block should be dedicated to high-priority transactions,
 134     // included regardless of the fees they pay
 135     unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", DEFAULT_BLOCK_PRIORITY_SIZE);
 136     nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
 137
 138     // Minimum block size you want to create; block will be filled with free transactions
 139     // until there are no more or the block reaches this size:
 140     unsigned int nBlockMinSize = GetArg("-blockminsize", DEFAULT_BLOCK_MIN_SIZE);
 141     nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
 142
 143     // Collect memory pool transactions into the block
 144     CAmount nFees = 0;
 145
 146     {
 147         LOCK2(cs_main, mempool.cs);
 148         CBlockIndex* pindexPrev = chainActive.Tip();
 149         const int nHeight = pindexPrev->nHeight + 1;
 150         pblock->nTime = GetAdjustedTime();
 151         const int64_t nMedianTimePast = pindexPrev->GetMedianTimePast();
 152         CCoinsViewCache view(pcoinsTip);
 153
 154         // Priority order to process transactions
 155         list<COrphan> vOrphan; // list memory doesn't move
 156         map<uint256, vector<COrphan*> > mapDependers;
 157         bool fPrintPriority = GetBoolArg("-printpriority", false);
 158
 159         // This vector will be sorted into a priority queue:
 160         vector<TxPriority> vecPriority;
 161         vecPriority.reserve(mempool.mapTx.size());
 162         for (CTxMemPool::indexed_transaction_set::iterator mi = mempool.mapTx.begin();
 163              mi != mempool.mapTx.end(); ++mi)
 164         {
 165             const CTransaction& tx = mi->GetTx();
 166
 167             int64_t nLockTimeCutoff = (STANDARD_LOCKTIME_VERIFY_FLAGS & LOCKTIME_MEDIAN_TIME_PAST)
 168                                     ? nMedianTimePast
 169                                     : pblock->GetBlockTime();
 170
 171             if (tx.IsCoinBase() || !IsFinalTx(tx, nHeight, nLockTimeCutoff))
 172                 continue;
 173
 174             COrphan* porphan = NULL;
 175             double dPriority = 0;
 176             CAmount nTotalIn = 0;
 177             bool fMissingInputs = false;
 178             BOOST_FOREACH(const CTxIn& txin, tx.vin)
 179             {
 180                 // Read prev transaction
 181                 if (!view.HaveCoins(txin.prevout.hash))
 182                 {
 183                     // This should never happen; all transactions in the memory
 184                     // pool should connect to either transactions in the chain
 185                     // or other transactions in the memory pool.
 186                     if (!mempool.mapTx.count(txin.prevout.hash))
 187                     {
 188                         LogPrintf("ERROR: mempool transaction missing input\n");
 189                         if (fDebug) assert("mempool transaction missing input" == 0);
 190                         fMissingInputs = true;
 191                         if (porphan)
 192                             vOrphan.pop_back();
 193                         break;
 194                     }
 195
 196                     // Has to wait for dependencies
 197                     if (!porphan)
 198                     {
 199                         // Use list for automatic deletion
 200                         vOrphan.push_back(COrphan(&tx));
 201                         porphan = &vOrphan.back();
 202                     }
 203                     mapDependers[txin.prevout.hash].push_back(porphan);
 204                     porphan->setDependsOn.insert(txin.prevout.hash);
 205                     nTotalIn += mempool.mapTx.find(txin.prevout.hash)->GetTx().vout[txin.prevout.n].nValue;
 206                     continue;
 207                 }
 208                 const CCoins* coins = view.AccessCoins(txin.prevout.hash);
 209                 assert(coins);
 210
 211                 CAmount nValueIn = coins->vout[txin.prevout.n].nValue;
 212                 nTotalIn += nValueIn;
 213
 214                 int nConf = nHeight - coins->nHeight;
 215
 216                 dPriority += (double)nValueIn * nConf;
 217             }
 218             if (fMissingInputs) continue;
 219
 220             // Priority is sum(valuein * age) / modified_txsize
 221             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 222             dPriority = tx.ComputePriority(dPriority, nTxSize);
 223
 224             uint256 hash = tx.GetHash();
 225             mempool.ApplyDeltas(hash, dPriority, nTotalIn);
 226
 227             CFeeRate feeRate(nTotalIn-tx.GetValueOut(), nTxSize);
 228
 229             if (porphan)
 230             {
 231                 porphan->dPriority = dPriority;
 232                 porphan->feeRate = feeRate;
 233             }
 234             else
 235                 vecPriority.push_back(TxPriority(dPriority, feeRate, &(mi->GetTx())));
 236         }
 237
 238         // Collect transactions into block
 239         uint64_t nBlockSize = 1000;
 240         uint64_t nBlockTx = 0;
 241         int nBlockSigOps = 100;
 242         bool fSortedByFee = (nBlockPrioritySize <= 0);
 243
 244         TxPriorityCompare comparer(fSortedByFee);
 245         std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 246
 247         while (!vecPriority.empty())
 248         {
 249             // Take highest priority transaction off the priority queue:
 250             double dPriority = vecPriority.front().get<0>();
 251             CFeeRate feeRate = vecPriority.front().get<1>();
 252             const CTransaction& tx = *(vecPriority.front().get<2>());
 253
 254             std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
 255             vecPriority.pop_back();
 256
 257             // Size limits
 258             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 259             if (nBlockSize + nTxSize >= nBlockMaxSize)
 260                 continue;
 261
 262             // Legacy limits on sigOps:
 263             unsigned int nTxSigOps = GetLegacySigOpCount(tx);
 264             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 265                 continue;
 266
 267             // Skip free transactions if we're past the minimum block size:
 268             const uint256& hash = tx.GetHash();
 269             double dPriorityDelta = 0;
 270             CAmount nFeeDelta = 0;
 271             mempool.ApplyDeltas(hash, dPriorityDelta, nFeeDelta);
 272             if (fSortedByFee && (dPriorityDelta <= 0) && (nFeeDelta <= 0) && (feeRate < ::minRelayTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
 273                 continue;
 274
 275             // Prioritise by fee once past the priority size or we run out of high-priority
 276             // transactions:
 277             if (!fSortedByFee &&
 278                 ((nBlockSize + nTxSize >= nBlockPrioritySize) || !AllowFree(dPriority)))
 279             {
 280                 fSortedByFee = true;
 281                 comparer = TxPriorityCompare(fSortedByFee);
 282                 std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 283             }
 284
 285             if (!view.HaveInputs(tx))
 286                 continue;
 287
 288             CAmount nTxFees = view.GetValueIn(tx)-tx.GetValueOut();
 289
 290             nTxSigOps += GetP2SHSigOpCount(tx, view);
 291             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 292                 continue;
 293
 294             // Note that flags: we don't want to set mempool/IsStandard()
 295             // policy here, but we still have to ensure that the block we
 296             // create only contains transactions that are valid in new blocks.
 297             CValidationState state;
 298             if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true))
 299                 continue;
 300
 301             UpdateCoins(tx, state, view, nHeight);
 302
 303             // Added
 304             pblock->vtx.push_back(tx);
 305             pblocktemplate->vTxFees.push_back(nTxFees);
 306             pblocktemplate->vTxSigOps.push_back(nTxSigOps);
 307             nBlockSize += nTxSize;
 308             ++nBlockTx;
 309             nBlockSigOps += nTxSigOps;
 310             nFees += nTxFees;
 311
 312             if (fPrintPriority)
 313             {
 314                 LogPrintf("priority %.1f fee %s txid %s\n",
 315                     dPriority, feeRate.ToString(), tx.GetHash().ToString());
 316             }
 317
 318             // Add transactions that depend on this one to the priority queue
 319             if (mapDependers.count(hash))
 320             {
 321                 BOOST_FOREACH(COrphan* porphan, mapDependers[hash])
 322                 {
 323                     if (!porphan->setDependsOn.empty())
 324                     {
 325                         porphan->setDependsOn.erase(hash);
 326                         if (porphan->setDependsOn.empty())
 327                         {
 328                             vecPriority.push_back(TxPriority(porphan->dPriority, porphan->feeRate, porphan->ptx));
 329                             std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
 330                         }
 331                     }
 332                 }
 333             }
 334         }
 335
 336         nLastBlockTx = nBlockTx;
 337         nLastBlockSize = nBlockSize;
 338         LogPrintf("CreateNewBlock(): total size %u\n", nBlockSize);
 339
 340         // Compute final coinbase transaction.
 341         txNew.vout[0].nValue = nFees + GetBlockSubsidy(nHeight, chainparams.GetConsensus());
 342         txNew.vin[0].scriptSig = CScript() << nHeight << OP_0;
 343         pblock->vtx[0] = txNew;
 344         pblocktemplate->vTxFees[0] = -nFees;
 345
 346         // Fill in header
 347         pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
 348         UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
 349         pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock, chainparams.GetConsensus());
 350         pblock->nNonce         = 0;
 351         pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 352
 353         CValidationState state;
 354         if (!TestBlockValidity(state, chainparams, *pblock, pindexPrev, false, false))
 355             throw std::runtime_error("CreateNewBlock(): TestBlockValidity failed");
 356     }
 357
 358     return pblocktemplate.release();
 359 }
 360
 361 void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
 362 {
 363     // Update nExtraNonce
 364     static uint256 hashPrevBlock;
 365     if (hashPrevBlock != pblock->hashPrevBlock)
 366     {
 367         nExtraNonce = 0;
 368         hashPrevBlock = pblock->hashPrevBlock;
 369     }
 370     ++nExtraNonce;
 371     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
 372     CMutableTransaction txCoinbase(pblock->vtx[0]);
 373     txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
 374     assert(txCoinbase.vin[0].scriptSig.size() <= 100);
 375
 376     pblock->vtx[0] = txCoinbase;
 377     pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
 378 }
 379
 380 //////////////////////////////////////////////////////////////////////////////
 381 //
 382 // Internal miner
 383 //
 384
 385 //
 386 // ScanHash scans nonces looking for a hash with at least some zero bits.
 387 // The nonce is usually preserved between calls, but periodically or if the
 388 // nonce is 0xffff0000 or above, the block is rebuilt and nNonce starts over at
 389 // zero.
 390 //
 391 bool static ScanHash(const CBlockHeader *pblock, uint32_t& nNonce, uint256 *phash)
 392 {
 393     // Write the first 76 bytes of the block header to a double-SHA256 state.
 394     CHash256 hasher;
 395     CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
 396     ss << *pblock;
 397     assert(ss.size() == 80);
 398     hasher.Write((unsigned char*)&ss[0], 76);
 399
 400     while (true) {
 401         nNonce++;
 402
 403         // Write the last 4 bytes of the block header (the nonce) to a copy of
 404         // the double-SHA256 state, and compute the result.
 405         CHash256(hasher).Write((unsigned char*)&nNonce, 4).Finalize((unsigned char*)phash);
 406
 407         // Return the nonce if the hash has at least some zero bits,
 408         // caller will check if it has enough to reach the target
 409         if (((uint16_t*)phash)[15] == 0)
 410             return true;
 411
 412         // If nothing found after trying for a while, return -1
 413         if ((nNonce & 0xfff) == 0)
 414             return false;
 415     }
 416 }
 417
 418 static bool ProcessBlockFound(const CBlock* pblock, const CChainParams& chainparams)
 419 {
 420     LogPrintf("%s\n", pblock->ToString());
 421     LogPrintf("generated %s\n", FormatMoney(pblock->vtx[0].vout[0].nValue));
 422
 423     // Found a solution
 424     {
 425         LOCK(cs_main);
 426         if (pblock->hashPrevBlock != chainActive.Tip()->GetBlockHash())
 427             return error("BitcoinMiner: generated block is stale");
 428     }
 429
 430     // Inform about the new block
 431     GetMainSignals().BlockFound(pblock->GetHash());
 432
 433     // Process this block the same as if we had received it from another node
 434     CValidationState state;
 435     if (!ProcessNewBlock(state, chainparams, NULL, pblock, true, NULL))
 436         return error("BitcoinMiner: ProcessNewBlock, block not accepted");
 437
 438     return true;
 439 }
 440
 441 void static BitcoinMiner(const CChainParams& chainparams)
 442 {
 443     LogPrintf("BitcoinMiner started\n");
 444     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 445     RenameThread("bitcoin-miner");
 446
 447     unsigned int nExtraNonce = 0;
 448
 449     boost::shared_ptr<CReserveScript> coinbaseScript;
 450     GetMainSignals().ScriptForMining(coinbaseScript);
 451
 452     try {
 453         // Throw an error if no script was provided.  This can happen
 454         // due to some internal error but also if the keypool is empty.
 455         // In the latter case, already the pointer is NULL.
 456         if (!coinbaseScript || coinbaseScript->reserveScript.empty())
 457             throw std::runtime_error("No coinbase script available (mining requires a wallet)");
 458
 459         while (true) {
 460             if (chainparams.MiningRequiresPeers()) {
 461                 // Busy-wait for the network to come online so we don't waste time mining
 462                 // on an obsolete chain. In regtest mode we expect to fly solo.
 463                 do {
 464                     bool fvNodesEmpty;
 465                     {
 466                         LOCK(cs_vNodes);
 467                         fvNodesEmpty = vNodes.empty();
 468                     }
 469                     if (!fvNodesEmpty && !IsInitialBlockDownload())
 470                         break;
 471                     MilliSleep(1000);
 472                 } while (true);
 473             }
 474
 475             //
 476             // Create new block
 477             //
 478             unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
 479             CBlockIndex* pindexPrev = chainActive.Tip();
 480
 481             auto_ptr<CBlockTemplate> pblocktemplate(CreateNewBlock(chainparams, coinbaseScript->reserveScript));
 482             if (!pblocktemplate.get())
 483             {
 484                 LogPrintf("Error in BitcoinMiner: Keypool ran out, please call keypoolrefill before restarting the mining thread\n");
 485                 return;
 486             }
 487             CBlock *pblock = &pblocktemplate->block;
 488             IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
 489
 490             LogPrintf("Running BitcoinMiner with %u transactions in block (%u bytes)\n", pblock->vtx.size(),
 491                 ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
 492
 493             //
 494             // Search
 495             //
 496             int64_t nStart = GetTime();
 497             arith_uint256 hashTarget = arith_uint256().SetCompact(pblock->nBits);
 498             uint256 hash;
 499             uint32_t nNonce = 0;
 500             while (true) {
 501                 // Check if something found
 502                 if (ScanHash(pblock, nNonce, &hash))
 503                 {
 504                     if (UintToArith256(hash) <= hashTarget)
 505                     {
 506                         // Found a solution
 507                         pblock->nNonce = nNonce;
 508                         assert(hash == pblock->GetHash());
 509
 510                         SetThreadPriority(THREAD_PRIORITY_NORMAL);
 511                         LogPrintf("BitcoinMiner:\n");
 512                         LogPrintf("proof-of-work found  \n  hash: %s  \ntarget: %s\n", hash.GetHex(), hashTarget.GetHex());
 513                         ProcessBlockFound(pblock, chainparams);
 514                         SetThreadPriority(THREAD_PRIORITY_LOWEST);
 515                         coinbaseScript->KeepScript();
 516
 517                         // In regression test mode, stop mining after a block is found.
 518                         if (chainparams.MineBlocksOnDemand())
 519                             throw boost::thread_interrupted();
 520
 521                         break;
 522                     }
 523                 }
 524
 525                 // Check for stop or if block needs to be rebuilt
 526                 boost::this_thread::interruption_point();
 527                 // Regtest mode doesn't require peers
 528                 if (vNodes.empty() && chainparams.MiningRequiresPeers())
 529                     break;
 530                 if (nNonce >= 0xffff0000)
 531                     break;
 532                 if (mempool.GetTransactionsUpdated() != nTransactionsUpdatedLast && GetTime() - nStart > 60)
 533                     break;
 534                 if (pindexPrev != chainActive.Tip())
 535                     break;
 536
 537                 // Update nTime every few seconds
 538                 if (UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev) < 0)
 539                     break; // Recreate the block if the clock has run backwards,
 540                            // so that we can use the correct time.
 541                 if (chainparams.GetConsensus().fPowAllowMinDifficultyBlocks)
 542                 {
 543                     // Changing pblock->nTime can change work required on testnet:
 544                     hashTarget.SetCompact(pblock->nBits);
 545                 }
 546             }
 547         }
 548     }
 549     catch (const boost::thread_interrupted&)
 550     {
 551         LogPrintf("BitcoinMiner terminated\n");
 552         throw;
 553     }
 554     catch (const std::runtime_error &e)
 555     {
 556         LogPrintf("BitcoinMiner runtime error: %s\n", e.what());
 557         return;
 558     }
 559 }
 560
 561 void GenerateBitcoins(bool fGenerate, int nThreads, const CChainParams& chainparams)
 562 {
 563     static boost::thread_group* minerThreads = NULL;
 564
 565     if (nThreads < 0)
 566         nThreads = GetNumCores();
 567
 568     if (minerThreads != NULL)
 569     {
 570         minerThreads->interrupt_all();
 571         delete minerThreads;
 572         minerThreads = NULL;
 573     }
 574
 575     if (nThreads == 0 || !fGenerate)
 576         return;
 577
 578     minerThreads = new boost::thread_group();
 579     for (int i = 0; i < nThreads; i++)
 580         minerThreads->create_thread(boost::bind(&BitcoinMiner, boost::cref(chainparams)));
 581 }