比特币源码解读之线程处理-矿工线程

(本文使用的是比特币v0.1.0版本 点击下载源码)

• 新建矿工线程
• 生成公钥和私钥
• 创建创币交易
• 创建新块并保存创币交易
• 收集最新的验证通过的交易
• 获取目标难度
• 获取随机生成的难度
• 工作量证明

  比特币源码解读之线程处理分为两篇，矿工线程处理和其他线程处理两篇，本文描述矿工线程处理，主要包含创币交易的产生、当前交易的打包处理，工作量等相关内容。流程图如下所示:

新建矿工线程

   
   
   
   

    
    
    
    
if (_beginthread(ThreadBitcoinMiner, 0, NULL) == -1)
    
    
    
    
     printf("Error: _beginthread(ThreadBitcoinMiner) failed\n");
   
   
   
   

执行矿工处理函数

   
   
   
   

    
    
    
    
void ThreadBitcoinMiner(void* parg)
    
    
    
    
{
    
    
    
    
    vfThreadRunning[3] = true;
    
    
    
    
    CheckForShutdown(3);
    
    
    
    
    try
    
    
    
    
    {
    
    
    
    
        bool fRet = BitcoinMiner();
    
    
    
    
        printf("BitcoinMiner returned %s\n\n\n", fRet ? "true" : "false");
    
    
    
    
    }
    
    
    
    
    CATCH_PRINT_EXCEPTION("BitcoinMiner()")
    
    
    
    
    vfThreadRunning[3] = false;
    
    
    
    
}
   
   
   
   

生成公钥和私钥

利用openssl库生成

   
   
   
   

    
    
    
    
CKey key;
    
    
    
    
key.MakeNewKey();
    
    
    
    

    
    
    
    
void MakeNewKey()
    
    
    
    
{
    
    
    
    
    if (!EC_KEY_generate_key(pkey))
    
    
    
    
    throw key_error("CKey::MakeNewKey() : EC_KEY_generate_key failed");
    
    
    
    
}
   
   
   
   

创建创币交易

输入为NULL，输出为本节点地址

   
   
   
   

    
    
    
    
CTransaction txNew;
    
    
    
    
txNew.vin.resize(1);
    
    
    
    
txNew.vin[0].prevout.SetNull();
    
    
    
    
txNew.vin[0].scriptSig << nBits << ++bnExtraNonce;
    
    
    
    
txNew.vout.resize(1);
    
    
    
    
txNew.vout[0].scriptPubKey << key.GetPubKey() << OP_CHECKSIG;
   
   
   
   

创建新块并保存创币交易

   
   
   
   

    
    
    
    
auto_ptr<CBlock> pblock(new CBlock());
    
    
    
    
if (!pblock.get())
    
    
    
    
return false;
    
    
    
    

    
    
    
    
// Add our coinbase tx as first transaction
    
    
    
    
pblock->vtx.push_back(txNew);
   
   
   
   

收集最新的验证通过的交易

结束条件是：
(1)mapTransactions中所有交易处理完
(2)区块大小达到 MAX_SIZE/2才结束。

   
   
   
   

    
    
    
    
CTxDB txdb("r");
    
    
    
    
map<uint256, CTxIndex> mapTestPool;
    
    
    
    
vector vfAlreadyAdded(mapTransactions.size());
    
    
    
    
bool fFoundSomething = true;
    
    
    
    
unsigned int nBlockSize = 0;
    
    
    
    
while (fFoundSomething && nBlockSize < MAX_SIZE/2)
    
    
    
    
{
    
    
    
    
    fFoundSomething = false;
    
    
    
    
    unsigned int n = 0;
    
    
    
    
    for (map<uint256, CTransaction>::iterator mi = mapTransactions.begin(); mi != mapTransactions.end(); ++mi, ++n)
    
    
    
    
    {
    
    
    
    
        if (vfAlreadyAdded[n])
    
    
    
    
        continue;
    
    
    
    
        CTransaction& tx = (*mi).second;
    
    
    
    
        if (tx.IsCoinBase() || !tx.IsFinal())
    
    
    
    
        continue;
    
    
    
    

    
    
    
    
        // Transaction fee requirements, mainly only needed for flood control
    
    
    
    
        // Under 10K (about 80 inputs) is free for first 100 transactions
    
    
    
    
        // Base rate is 0.01 per KB
    
    
    
    
        int64 nMinFee = tx.GetMinFee(pblock->vtx.size() < 100);
    
    
    
    

    
    
    
    
        map<uint256, CTxIndex> mapTestPoolTmp(mapTestPool);
    
    
    
    
        if (!tx.ConnectInputs(txdb, mapTestPoolTmp, CDiskTxPos(1,1,1), 0, nFees, false, true, nMinFee))
    
    
    
    
        continue;
    
    
    
    
        swap(mapTestPool, mapTestPoolTmp);
    
    
    
    

    
    
    
    
        pblock->vtx.push_back(tx);
    
    
    
    
        nBlockSize += ::GetSerializeSize(tx, SER_NETWORK);
    
    
    
    
        vfAlreadyAdded[n] = true;
    
    
    
    
        fFoundSomething = true;
    
    
    
    
    }
    
    
    
    
}
   
   
   
   

保存输出的字节数、创币交易以及缴费到新块中

   
   
   
   

    
    
    
    
pblock->nBits = nBits;
    
    
    
    
pblock->vtx[0].vout[0].nValue = pblock->GetBlockValue(nFees);
   
   
   
   

计算交易的Merkle值

   
   
   
   

    
    
    
    
tmp.block.nVersion       = pblock->nVersion;
    
    
    
    
tmp.block.hashPrevBlock  = pblock->hashPrevBlock  = (pindexPrev ? pindexPrev->GetBlockHash() : 0);
    
    
    
    
tmp.block.hashMerkleRoot = pblock->hashMerkleRoot = pblock->BuildMerkleTree();
    
    
    
    
tmp.block.nTime          = pblock->nTime          = max((pindexPrev ? pindexPrev->GetMedianTimePast()+1 : 0), GetAdjustedTime());
    
    
    
    
tmp.block.nBits          = pblock->nBits          = nBits;
    
    
    
    
tmp.block.nNonce         = pblock->nNonce         = 1;
   
   
   
   

获取目标难度

   
   
   
   

    
    
    
    
uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
   
   
   
   

获取随机生成的难度

   
   
   
   

    
    
    
    
unsigned int nBlocks0 = FormatHashBlocks(&tmp.block, sizeof(tmp.block));
    
    
    
    
unsigned int nBlocks1 = FormatHashBlocks(&tmp.hash1, sizeof(tmp.hash1));
    
    
    
    
... ...
    
    
    
    
BlockSHA256(&tmp.block, nBlocks0, &tmp.hash1);
    
    
    
    
BlockSHA256(&tmp.hash1, nBlocks1, &hash);
   
   
   
   

工作量证明

如果当前随机hash小于等于目标hash值，表示该区块满足难度要求，则处理该区块ProcessBlock（区块处理在比特币源码解读之挖矿一文中介绍）

   
   
   
   

    
    
    
    
if (hash <= hashTarget)
    
    
    
    
{
    
    
    
    
    pblock->nNonce = tmp.block.nNonce;
    
    
    
    
    ... ...
    
    
    
    
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_NORMAL);
    
    
    
    
    CRITICAL_BLOCK(cs_main)
    
    
    
    
    {
    
    
    
    
        // Save key
    
    
    
    
        if (!AddKey(key))
    
    
    
    
        return false;
    
    
    
    
        key.MakeNewKey();
    
    
    
    

    
    
    
    
        // Process this block the same as if we had received it from another node
    
    
    
    
        if (!ProcessBlock(NULL, pblock.release()))
    
    
    
    
        printf("ERROR in BitcoinMiner, ProcessBlock, block not accepted\n");
    
    
    
    
    }
    
    
    
    
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_LOWEST);
    
    
    
    

    
    
    
    
    Sleep(500);
    
    
    
    
    break;
    
    
    
    
}
   
   
   
   

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作者：雨后的蚊子

原文链接：http://www.360bchain.com/article/59.html