src/miner.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2013 The Bitcoin developers
   3 // Distributed under the MIT/X11 software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include "miner.h"
   7 #include "main.h"
   8
   9 double dHashesPerSec = 0.0;
  10 int64 nHPSTimerStart = 0;
  11
  12 //////////////////////////////////////////////////////////////////////////////
  13 //
  14 // BitcoinMiner
  15 //
  16
  17 int static FormatHashBlocks(void* pbuffer, unsigned int len)
  18 {
  19     unsigned char* pdata = (unsigned char*)pbuffer;
  20     unsigned int blocks = 1 + ((len + 8) / 64);
  21     unsigned char* pend = pdata + 64 * blocks;
  22     memset(pdata + len, 0, 64 * blocks - len);
  23     pdata[len] = 0x80;
  24     unsigned int bits = len * 8;
  25     pend[-1] = (bits >> 0) & 0xff;
  26     pend[-2] = (bits >> 8) & 0xff;
  27     pend[-3] = (bits >> 16) & 0xff;
  28     pend[-4] = (bits >> 24) & 0xff;
  29     return blocks;
  30 }
  31
  32 static const unsigned int pSHA256InitState[8] =
  33 {0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19};
  34
  35 void SHA256Transform(void* pstate, void* pinput, const void* pinit)
  36 {
  37     SHA256_CTX ctx;
  38     unsigned char data[64];
  39
  40     SHA256_Init(&ctx);
  41
  42     for (int i = 0; i < 16; i++)
  43         ((uint32_t*)data)[i] = ByteReverse(((uint32_t*)pinput)[i]);
  44
  45     for (int i = 0; i < 8; i++)
  46         ctx.h[i] = ((uint32_t*)pinit)[i];
  47
  48     SHA256_Update(&ctx, data, sizeof(data));
  49     for (int i = 0; i < 8; i++)
  50         ((uint32_t*)pstate)[i] = ctx.h[i];
  51 }
  52
  53 //
  54 // ScanHash scans nonces looking for a hash with at least some zero bits.
  55 // It operates on big endian data.  Caller does the byte reversing.
  56 // All input buffers are 16-byte aligned.  nNonce is usually preserved
  57 // between calls, but periodically or if nNonce is 0xffff0000 or above,
  58 // the block is rebuilt and nNonce starts over at zero.
  59 //
  60 unsigned int static ScanHash_CryptoPP(char* pmidstate, char* pdata, char* phash1, char* phash, unsigned int& nHashesDone)
  61 {
  62     unsigned int& nNonce = *(unsigned int*)(pdata + 12);
  63     for (;;)
  64     {
  65         // Crypto++ SHA256
  66         // Hash pdata using pmidstate as the starting state into
  67         // pre-formatted buffer phash1, then hash phash1 into phash
  68         nNonce++;
  69         SHA256Transform(phash1, pdata, pmidstate);
  70         SHA256Transform(phash, phash1, pSHA256InitState);
  71
  72         // Return the nonce if the hash has at least some zero bits,
  73         // caller will check if it has enough to reach the target
  74         if (((unsigned short*)phash)[14] == 0)
  75             return nNonce;
  76
  77         // If nothing found after trying for a while, return -1
  78         if ((nNonce & 0xffff) == 0)
  79         {
  80             nHashesDone = 0xffff+1;
  81             return (unsigned int) -1;
  82         }
  83         if ((nNonce & 0xfff) == 0)
  84             boost::this_thread::interruption_point();
  85     }
  86 }
  87
  88 // Some explaining would be appreciated
  89 class COrphan
  90 {
  91 public:
  92     CTransaction* ptx;
  93     set<uint256> setDependsOn;
  94     double dPriority;
  95     double dFeePerKb;
  96
  97     COrphan(CTransaction* ptxIn)
  98     {
  99         ptx = ptxIn;
 100         dPriority = dFeePerKb = 0;
 101     }
 102
 103     void print() const
 104     {
 105         LogPrintf("COrphan(hash=%s, dPriority=%.1f, dFeePerKb=%.1f)\n",
 106                ptx->GetHash().ToString().c_str(), dPriority, dFeePerKb);
 107         BOOST_FOREACH(uint256 hash, setDependsOn)
 108             LogPrintf("   setDependsOn %s\n", hash.ToString().c_str());
 109     }
 110 };
 111
 112
 113 uint64 nLastBlockTx = 0;
 114 uint64 nLastBlockSize = 0;
 115
 116 // We want to sort transactions by priority and fee, so:
 117 typedef boost::tuple<double, double, CTransaction*> TxPriority;
 118 class TxPriorityCompare
 119 {
 120     bool byFee;
 121 public:
 122     TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
 123     bool operator()(const TxPriority& a, const TxPriority& b)
 124     {
 125         if (byFee)
 126         {
 127             if (a.get<1>() == b.get<1>())
 128                 return a.get<0>() < b.get<0>();
 129             return a.get<1>() < b.get<1>();
 130         }
 131         else
 132         {
 133             if (a.get<0>() == b.get<0>())
 134                 return a.get<1>() < b.get<1>();
 135             return a.get<0>() < b.get<0>();
 136         }
 137     }
 138 };
 139
 140 CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
 141 {
 142     // Create new block
 143     auto_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
 144     if(!pblocktemplate.get())
 145         return NULL;
 146     CBlock *pblock = &pblocktemplate->block; // pointer for convenience
 147
 148     // Create coinbase tx
 149     CTransaction txNew;
 150     txNew.vin.resize(1);
 151     txNew.vin[0].prevout.SetNull();
 152     txNew.vout.resize(1);
 153     txNew.vout[0].scriptPubKey = scriptPubKeyIn;
 154
 155     // Add our coinbase tx as first transaction
 156     pblock->vtx.push_back(txNew);
 157     pblocktemplate->vTxFees.push_back(-1); // updated at end
 158     pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 159
 160     // Largest block you're willing to create:
 161     unsigned int nBlockMaxSize = GetArg("-blockmaxsize", MAX_BLOCK_SIZE_GEN/2);
 162     // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
 163     nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));
 164
 165     // How much of the block should be dedicated to high-priority transactions,
 166     // included regardless of the fees they pay
 167     unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", DEFAULT_BLOCK_PRIORITY_SIZE);
 168     nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
 169
 170     // Minimum block size you want to create; block will be filled with free transactions
 171     // until there are no more or the block reaches this size:
 172     unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
 173     nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
 174
 175     // Collect memory pool transactions into the block
 176     int64 nFees = 0;
 177     {
 178         LOCK2(cs_main, mempool.cs);
 179         CBlockIndex* pindexPrev = chainActive.Tip();
 180         CCoinsViewCache view(*pcoinsTip, true);
 181
 182         // Priority order to process transactions
 183         list<COrphan> vOrphan; // list memory doesn't move
 184         map<uint256, vector<COrphan*> > mapDependers;
 185         bool fPrintPriority = GetBoolArg("-printpriority", false);
 186
 187         // This vector will be sorted into a priority queue:
 188         vector<TxPriority> vecPriority;
 189         vecPriority.reserve(mempool.mapTx.size());
 190         for (map<uint256, CTransaction>::iterator mi = mempool.mapTx.begin(); mi != mempool.mapTx.end(); ++mi)
 191         {
 192             CTransaction& tx = (*mi).second;
 193             if (tx.IsCoinBase() || !IsFinalTx(tx))
 194                 continue;
 195
 196             COrphan* porphan = NULL;
 197             double dPriority = 0;
 198             int64 nTotalIn = 0;
 199             bool fMissingInputs = false;
 200             BOOST_FOREACH(const CTxIn& txin, tx.vin)
 201             {
 202                 // Read prev transaction
 203                 if (!view.HaveCoins(txin.prevout.hash))
 204                 {
 205                     // This should never happen; all transactions in the memory
 206                     // pool should connect to either transactions in the chain
 207                     // or other transactions in the memory pool.
 208                     if (!mempool.mapTx.count(txin.prevout.hash))
 209                     {
 210                         LogPrintf("ERROR: mempool transaction missing input\n");
 211                         if (fDebug) assert("mempool transaction missing input" == 0);
 212                         fMissingInputs = true;
 213                         if (porphan)
 214                             vOrphan.pop_back();
 215                         break;
 216                     }
 217
 218                     // Has to wait for dependencies
 219                     if (!porphan)
 220                     {
 221                         // Use list for automatic deletion
 222                         vOrphan.push_back(COrphan(&tx));
 223                         porphan = &vOrphan.back();
 224                     }
 225                     mapDependers[txin.prevout.hash].push_back(porphan);
 226                     porphan->setDependsOn.insert(txin.prevout.hash);
 227                     nTotalIn += mempool.mapTx[txin.prevout.hash].vout[txin.prevout.n].nValue;
 228                     continue;
 229                 }
 230                 const CCoins &coins = view.GetCoins(txin.prevout.hash);
 231
 232                 int64 nValueIn = coins.vout[txin.prevout.n].nValue;
 233                 nTotalIn += nValueIn;
 234
 235                 int nConf = pindexPrev->nHeight - coins.nHeight + 1;
 236
 237                 dPriority += (double)nValueIn * nConf;
 238             }
 239             if (fMissingInputs) continue;
 240
 241             // Priority is sum(valuein * age) / modified_txsize
 242             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 243             unsigned int nTxSizeMod = nTxSize;
 244             // In order to avoid disincentivizing cleaning up the UTXO set we don't count
 245             // the constant overhead for each txin and up to 110 bytes of scriptSig (which
 246             // is enough to cover a compressed pubkey p2sh redemption) for priority.
 247             // Providing any more cleanup incentive than making additional inputs free would
 248             // risk encouraging people to create junk outputs to redeem later.
 249             BOOST_FOREACH(const CTxIn& txin, tx.vin)
 250             {
 251                 unsigned int offset = 41U + min(110U, (unsigned int)txin.scriptSig.size());
 252                 if (nTxSizeMod > offset)
 253                     nTxSizeMod -= offset;
 254             }
 255             dPriority /= nTxSizeMod;
 256
 257             // This is a more accurate fee-per-kilobyte than is used by the client code, because the
 258             // client code rounds up the size to the nearest 1K. That's good, because it gives an
 259             // incentive to create smaller transactions.
 260             double dFeePerKb =  double(nTotalIn-GetValueOut(tx)) / (double(nTxSize)/1000.0);
 261
 262             if (porphan)
 263             {
 264                 porphan->dPriority = dPriority;
 265                 porphan->dFeePerKb = dFeePerKb;
 266             }
 267             else
 268                 vecPriority.push_back(TxPriority(dPriority, dFeePerKb, &(*mi).second));
 269         }
 270
 271         // Collect transactions into block
 272         uint64 nBlockSize = 1000;
 273         uint64 nBlockTx = 0;
 274         int nBlockSigOps = 100;
 275         bool fSortedByFee = (nBlockPrioritySize <= 0);
 276
 277         TxPriorityCompare comparer(fSortedByFee);
 278         std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 279
 280         while (!vecPriority.empty())
 281         {
 282             // Take highest priority transaction off the priority queue:
 283             double dPriority = vecPriority.front().get<0>();
 284             double dFeePerKb = vecPriority.front().get<1>();
 285             CTransaction& tx = *(vecPriority.front().get<2>());
 286
 287             std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
 288             vecPriority.pop_back();
 289
 290             // Size limits
 291             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 292             if (nBlockSize + nTxSize >= nBlockMaxSize)
 293                 continue;
 294
 295             // Legacy limits on sigOps:
 296             unsigned int nTxSigOps = GetLegacySigOpCount(tx);
 297             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 298                 continue;
 299
 300             // Skip free transactions if we're past the minimum block size:
 301             if (fSortedByFee && (dFeePerKb < CTransaction::nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
 302                 continue;
 303
 304             // Prioritize by fee once past the priority size or we run out of high-priority
 305             // transactions:
 306             if (!fSortedByFee &&
 307                 ((nBlockSize + nTxSize >= nBlockPrioritySize) || !AllowFree(dPriority)))
 308             {
 309                 fSortedByFee = true;
 310                 comparer = TxPriorityCompare(fSortedByFee);
 311                 std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 312             }
 313
 314             if (!view.HaveInputs(tx))
 315                 continue;
 316
 317             int64 nTxFees = view.GetValueIn(tx)-GetValueOut(tx);
 318
 319             nTxSigOps += GetP2SHSigOpCount(tx, view);
 320             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 321                 continue;
 322
 323             CValidationState state;
 324             if (!CheckInputs(tx, state, view, true, SCRIPT_VERIFY_P2SH))
 325                 continue;
 326
 327             CTxUndo txundo;
 328             uint256 hash = tx.GetHash();
 329             UpdateCoins(tx, state, view, txundo, pindexPrev->nHeight+1, hash);
 330
 331             // Added
 332             pblock->vtx.push_back(tx);
 333             pblocktemplate->vTxFees.push_back(nTxFees);
 334             pblocktemplate->vTxSigOps.push_back(nTxSigOps);
 335             nBlockSize += nTxSize;
 336             ++nBlockTx;
 337             nBlockSigOps += nTxSigOps;
 338             nFees += nTxFees;
 339
 340             if (fPrintPriority)
 341             {
 342                 LogPrintf("priority %.1f feeperkb %.1f txid %s\n",
 343                        dPriority, dFeePerKb, tx.GetHash().ToString().c_str());
 344             }
 345
 346             // Add transactions that depend on this one to the priority queue
 347             if (mapDependers.count(hash))
 348             {
 349                 BOOST_FOREACH(COrphan* porphan, mapDependers[hash])
 350                 {
 351                     if (!porphan->setDependsOn.empty())
 352                     {
 353                         porphan->setDependsOn.erase(hash);
 354                         if (porphan->setDependsOn.empty())
 355                         {
 356                             vecPriority.push_back(TxPriority(porphan->dPriority, porphan->dFeePerKb, porphan->ptx));
 357                             std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
 358                         }
 359                     }
 360                 }
 361             }
 362         }
 363
 364         nLastBlockTx = nBlockTx;
 365         nLastBlockSize = nBlockSize;
 366         LogPrintf("CreateNewBlock(): total size %"PRI64u"\n", nBlockSize);
 367
 368         pblock->vtx[0].vout[0].nValue = GetBlockValue(pindexPrev->nHeight+1, nFees);
 369         pblocktemplate->vTxFees[0] = -nFees;
 370
 371         // Fill in header
 372         pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
 373         UpdateTime(*pblock, pindexPrev);
 374         pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock);
 375         pblock->nNonce         = 0;
 376         pblock->vtx[0].vin[0].scriptSig = CScript() << OP_0 << OP_0;
 377         pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 378
 379         CBlockIndex indexDummy(*pblock);
 380         indexDummy.pprev = pindexPrev;
 381         indexDummy.nHeight = pindexPrev->nHeight + 1;
 382         CCoinsViewCache viewNew(*pcoinsTip, true);
 383         CValidationState state;
 384         if (!ConnectBlock(*pblock, state, &indexDummy, viewNew, true))
 385             throw std::runtime_error("CreateNewBlock() : ConnectBlock failed");
 386     }
 387
 388     return pblocktemplate.release();
 389 }
 390
 391 CBlockTemplate* CreateNewBlockWithKey(CReserveKey& reservekey)
 392 {
 393     CPubKey pubkey;
 394     if (!reservekey.GetReservedKey(pubkey))
 395         return NULL;
 396
 397     CScript scriptPubKey = CScript() << pubkey << OP_CHECKSIG;
 398     return CreateNewBlock(scriptPubKey);
 399 }
 400
 401 void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
 402 {
 403     // Update nExtraNonce
 404     static uint256 hashPrevBlock;
 405     if (hashPrevBlock != pblock->hashPrevBlock)
 406     {
 407         nExtraNonce = 0;
 408         hashPrevBlock = pblock->hashPrevBlock;
 409     }
 410     ++nExtraNonce;
 411     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
 412     pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CBigNum(nExtraNonce)) + COINBASE_FLAGS;
 413     assert(pblock->vtx[0].vin[0].scriptSig.size() <= 100);
 414
 415     pblock->hashMerkleRoot = pblock->BuildMerkleTree();
 416 }
 417
 418
 419 void FormatHashBuffers(CBlock* pblock, char* pmidstate, char* pdata, char* phash1)
 420 {
 421     //
 422     // Pre-build hash buffers
 423     //
 424     struct
 425     {
 426         struct unnamed2
 427         {
 428             int nVersion;
 429             uint256 hashPrevBlock;
 430             uint256 hashMerkleRoot;
 431             unsigned int nTime;
 432             unsigned int nBits;
 433             unsigned int nNonce;
 434         }
 435         block;
 436         unsigned char pchPadding0[64];
 437         uint256 hash1;
 438         unsigned char pchPadding1[64];
 439     }
 440     tmp;
 441     memset(&tmp, 0, sizeof(tmp));
 442
 443     tmp.block.nVersion       = pblock->nVersion;
 444     tmp.block.hashPrevBlock  = pblock->hashPrevBlock;
 445     tmp.block.hashMerkleRoot = pblock->hashMerkleRoot;
 446     tmp.block.nTime          = pblock->nTime;
 447     tmp.block.nBits          = pblock->nBits;
 448     tmp.block.nNonce         = pblock->nNonce;
 449
 450     FormatHashBlocks(&tmp.block, sizeof(tmp.block));
 451     FormatHashBlocks(&tmp.hash1, sizeof(tmp.hash1));
 452
 453     // Byte swap all the input buffer
 454     for (unsigned int i = 0; i < sizeof(tmp)/4; i++)
 455         ((unsigned int*)&tmp)[i] = ByteReverse(((unsigned int*)&tmp)[i]);
 456
 457     // Precalc the first half of the first hash, which stays constant
 458     SHA256Transform(pmidstate, &tmp.block, pSHA256InitState);
 459
 460     memcpy(pdata, &tmp.block, 128);
 461     memcpy(phash1, &tmp.hash1, 64);
 462 }
 463
 464
 465 bool CheckWork(CBlock* pblock, CWallet& wallet, CReserveKey& reservekey)
 466 {
 467     uint256 hash = pblock->GetHash();
 468     uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 469
 470     if (hash > hashTarget)
 471         return false;
 472
 473     //// debug print
 474     LogPrintf("BitcoinMiner:\n");
 475     LogPrintf("proof-of-work found  \n  hash: %s  \ntarget: %s\n", hash.GetHex().c_str(), hashTarget.GetHex().c_str());
 476     pblock->print();
 477     LogPrintf("generated %s\n", FormatMoney(pblock->vtx[0].vout[0].nValue).c_str());
 478
 479     // Found a solution
 480     {
 481         LOCK(cs_main);
 482         if (pblock->hashPrevBlock != chainActive.Tip()->GetBlockHash())
 483             return error("BitcoinMiner : generated block is stale");
 484
 485         // Remove key from key pool
 486         reservekey.KeepKey();
 487
 488         // Track how many getdata requests this block gets
 489         {
 490             LOCK(wallet.cs_wallet);
 491             wallet.mapRequestCount[pblock->GetHash()] = 0;
 492         }
 493
 494         // Process this block the same as if we had received it from another node
 495         CValidationState state;
 496         if (!ProcessBlock(state, NULL, pblock))
 497             return error("BitcoinMiner : ProcessBlock, block not accepted");
 498     }
 499
 500     return true;
 501 }
 502
 503 void static BitcoinMiner(CWallet *pwallet)
 504 {
 505     LogPrintf("BitcoinMiner started\n");
 506     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 507     RenameThread("bitcoin-miner");
 508
 509     // Each thread has its own key and counter
 510     CReserveKey reservekey(pwallet);
 511     unsigned int nExtraNonce = 0;
 512
 513     try { while (true) {
 514         if (Params().NetworkID() != CChainParams::REGTEST) {
 515             // Busy-wait for the network to come online so we don't waste time mining
 516             // on an obsolete chain. In regtest mode we expect to fly solo.
 517             while (vNodes.empty())
 518                 MilliSleep(1000);
 519         }
 520
 521         //
 522         // Create new block
 523         //
 524         unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
 525         CBlockIndex* pindexPrev = chainActive.Tip();
 526
 527         auto_ptr<CBlockTemplate> pblocktemplate(CreateNewBlockWithKey(reservekey));
 528         if (!pblocktemplate.get())
 529             return;
 530         CBlock *pblock = &pblocktemplate->block;
 531         IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
 532
 533         LogPrintf("Running BitcoinMiner with %"PRIszu" transactions in block (%u bytes)\n", pblock->vtx.size(),
 534                ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
 535
 536         //
 537         // Pre-build hash buffers
 538         //
 539         char pmidstatebuf[32+16]; char* pmidstate = alignup<16>(pmidstatebuf);
 540         char pdatabuf[128+16];    char* pdata     = alignup<16>(pdatabuf);
 541         char phash1buf[64+16];    char* phash1    = alignup<16>(phash1buf);
 542
 543         FormatHashBuffers(pblock, pmidstate, pdata, phash1);
 544
 545         unsigned int& nBlockTime = *(unsigned int*)(pdata + 64 + 4);
 546         unsigned int& nBlockBits = *(unsigned int*)(pdata + 64 + 8);
 547         unsigned int& nBlockNonce = *(unsigned int*)(pdata + 64 + 12);
 548
 549
 550         //
 551         // Search
 552         //
 553         int64 nStart = GetTime();
 554         uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 555         uint256 hashbuf[2];
 556         uint256& hash = *alignup<16>(hashbuf);
 557         while (true)
 558         {
 559             unsigned int nHashesDone = 0;
 560             unsigned int nNonceFound;
 561
 562             // Crypto++ SHA256
 563             nNonceFound = ScanHash_CryptoPP(pmidstate, pdata + 64, phash1,
 564                                             (char*)&hash, nHashesDone);
 565
 566             // Check if something found
 567             if (nNonceFound != (unsigned int) -1)
 568             {
 569                 for (unsigned int i = 0; i < sizeof(hash)/4; i++)
 570                     ((unsigned int*)&hash)[i] = ByteReverse(((unsigned int*)&hash)[i]);
 571
 572                 if (hash <= hashTarget)
 573                 {
 574                     // Found a solution
 575                     pblock->nNonce = ByteReverse(nNonceFound);
 576                     assert(hash == pblock->GetHash());
 577
 578                     SetThreadPriority(THREAD_PRIORITY_NORMAL);
 579                     CheckWork(pblock, *pwallet, reservekey);
 580                     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 581
 582                     // In regression test mode, stop mining after a block is found. This
 583                     // allows developers to controllably generate a block on demand.
 584                     if (Params().NetworkID() == CChainParams::REGTEST)
 585                         throw boost::thread_interrupted();
 586
 587                     break;
 588                 }
 589             }
 590
 591             // Meter hashes/sec
 592             static int64 nHashCounter;
 593             if (nHPSTimerStart == 0)
 594             {
 595                 nHPSTimerStart = GetTimeMillis();
 596                 nHashCounter = 0;
 597             }
 598             else
 599                 nHashCounter += nHashesDone;
 600             if (GetTimeMillis() - nHPSTimerStart > 4000)
 601             {
 602                 static CCriticalSection cs;
 603                 {
 604                     LOCK(cs);
 605                     if (GetTimeMillis() - nHPSTimerStart > 4000)
 606                     {
 607                         dHashesPerSec = 1000.0 * nHashCounter / (GetTimeMillis() - nHPSTimerStart);
 608                         nHPSTimerStart = GetTimeMillis();
 609                         nHashCounter = 0;
 610                         static int64 nLogTime;
 611                         if (GetTime() - nLogTime > 30 * 60)
 612                         {
 613                             nLogTime = GetTime();
 614                             LogPrintf("hashmeter %6.0f khash/s\n", dHashesPerSec/1000.0);
 615                         }
 616                     }
 617                 }
 618             }
 619
 620             // Check for stop or if block needs to be rebuilt
 621             boost::this_thread::interruption_point();
 622             if (vNodes.empty() && Params().NetworkID() != CChainParams::REGTEST)
 623                 break;
 624             if (nBlockNonce >= 0xffff0000)
 625                 break;
 626             if (mempool.GetTransactionsUpdated() != nTransactionsUpdatedLast && GetTime() - nStart > 60)
 627                 break;
 628             if (pindexPrev != chainActive.Tip())
 629                 break;
 630
 631             // Update nTime every few seconds
 632             UpdateTime(*pblock, pindexPrev);
 633             nBlockTime = ByteReverse(pblock->nTime);
 634             if (TestNet())
 635             {
 636                 // Changing pblock->nTime can change work required on testnet:
 637                 nBlockBits = ByteReverse(pblock->nBits);
 638                 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 639             }
 640         }
 641     } }
 642     catch (boost::thread_interrupted)
 643     {
 644         LogPrintf("BitcoinMiner terminated\n");
 645         throw;
 646     }
 647 }
 648
 649 void GenerateBitcoins(bool fGenerate, CWallet* pwallet)
 650 {
 651     static boost::thread_group* minerThreads = NULL;
 652
 653     int nThreads = GetArg("-genproclimit", -1);
 654     if (nThreads < 0) {
 655         if (Params().NetworkID() == CChainParams::REGTEST)
 656             nThreads = 1;
 657         else
 658             nThreads = boost::thread::hardware_concurrency();
 659     }
 660
 661     if (minerThreads != NULL)
 662     {
 663         minerThreads->interrupt_all();
 664         delete minerThreads;
 665         minerThreads = NULL;
 666     }
 667
 668     if (nThreads == 0 || !fGenerate)
 669         return;
 670
 671     minerThreads = new boost::thread_group();
 672     for (int i = 0; i < nThreads; i++)
 673         minerThreads->create_thread(boost::bind(&BitcoinMiner, pwallet));
 674 }
 675
 676
 677