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