Value rewindchain(const Array& params, bool fHelp)
{
if (fHelp || params.size() < 1 || params.size() > 2)
throw runtime_error(
"rewindchain <number>\n"
"Remove <number> blocks from the chain.");
int nNumber = params[0].get_int();
if (nNumber < 0 || nNumber > nBestHeight)
throw runtime_error("Block number out of range.");
Object result;
int nRemoved = 0;
{
LOCK2(cs_main, pwalletMain->cs_wallet);
uint32_t nFileRet = 0;
uint8_t buffer[512];
LogPrintf("rewindchain %d\n", nNumber);
void* nFind;
for (int i = 0; i < nNumber; ++i)
{
memset(buffer, 0, sizeof(buffer));
FILE* fp = AppendBlockFile(false, nFileRet, "r+b");
if (!fp)
{
LogPrintf("AppendBlockFile failed.\n");
break;
};
errno = 0;
if (fseek(fp, 0, SEEK_END) != 0)
{
LogPrintf("fseek failed: %s\n", strerror(errno));
break;
};
long int fpos = ftell(fp);
if (fpos == -1)
{
LogPrintf("ftell failed: %s\n", strerror(errno));
break;
};
long int foundPos = -1;
long int readSize = sizeof(buffer) / 2;
while (fpos > 0)
{
if (fpos < (long int)sizeof(buffer) / 2)
readSize = fpos;
memcpy(buffer+readSize, buffer, readSize); // move last read data (incase token crosses a boundary)
fpos -= readSize;
if (fseek(fp, fpos, SEEK_SET) != 0)
{
LogPrintf("fseek failed: %s\n", strerror(errno));
break;
};
errno = 0;
if (fread(buffer, sizeof(uint8_t), readSize, fp) != (size_t)readSize)
{
if (errno != 0)
LogPrintf("fread failed: %s\n", strerror(errno));
else
LogPrintf("End of file.\n");
break;
};
uint32_t findPos = sizeof(buffer);
while (findPos > MESSAGE_START_SIZE)
{
if ((nFind = shellk::memrchr(buffer, Params().MessageStart()[0], findPos-MESSAGE_START_SIZE)))
{
if (memcmp(nFind, Params().MessageStart(), MESSAGE_START_SIZE) == 0)
{
foundPos = ((uint8_t*)nFind - buffer) + MESSAGE_START_SIZE;
break;
} else
{
findPos = ((uint8_t*)nFind - buffer);
// -- step over matched char that wasn't pchMessageStart
if (findPos > 0) // prevent findPos < 0 (unsigned)
findPos--;
};
} else
{
break; // pchMessageStart[0] not found in buffer
};
};
if (foundPos > -1)
break;
};
LogPrintf("fpos %d, foundPos %d.\n", fpos, foundPos);
if (foundPos < 0)
{
LogPrintf("block start not found.\n");
fclose(fp);
break;
};
CAutoFile blkdat(fp, SER_DISK, CLIENT_VERSION);
if (fseek(blkdat, fpos+foundPos, SEEK_SET) != 0)
{
LogPrintf("fseek blkdat failed: %s\n", strerror(errno));
break;
};
unsigned int nSize;
blkdat >> nSize;
LogPrintf("nSize %u .\n", nSize);
if (nSize < 1 || nSize > MAX_BLOCK_SIZE)
{
LogPrintf("block size error %u\n", nSize);
};
CBlock block;
blkdat >> block;
uint256 hashblock = block.GetHash();
LogPrintf("hashblock %s .\n", hashblock.ToString().c_str());
std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashblock);
if (mi != mapBlockIndex.end() && (*mi).second)
{
LogPrintf("block is in main chain.\n");
if (!mi->second->pprev)
{
LogPrintf("! mi->second.pprev\n");
} else
{
{
CBlock blockPrev; // strange way SetBestChain works, TODO: does it need the full block?
if (!blockPrev.ReadFromDisk(mi->second->pprev))
{
LogPrintf("blockPrev.ReadFromDisk failed %s.\n", mi->second->pprev->GetBlockHash().ToString().c_str());
break;
};
CTxDB txdb;
if (!blockPrev.SetBestChain(txdb, mi->second->pprev))
{
LogPrintf("SetBestChain failed.\n");
};
}
mi->second->pprev->pnext = NULL;
};
delete mi->second;
mapBlockIndex.erase(mi);
};
std::map<uint256, COrphanBlock*>::iterator miOph = mapOrphanBlocks.find(hashblock);
if (miOph != mapOrphanBlocks.end())
{
LogPrintf("block is an orphan.\n");
mapOrphanBlocks.erase(miOph);
};
CTxDB txdb;
for (vector<CTransaction>::iterator it = block.vtx.begin(); it != block.vtx.end(); ++it)
{
LogPrintf("EraseTxIndex().\n");
txdb.EraseTxIndex(*it);
};
LogPrintf("EraseBlockIndex().\n");
txdb.EraseBlockIndex(hashblock);
errno = 0;
if (ftruncate(fileno(fp), fpos+foundPos-MESSAGE_START_SIZE) != 0)
{
LogPrintf("ftruncate failed: %s\n", strerror(errno));
};
LogPrintf("hashBestChain %s, nBestHeight %d\n", hashBestChain.ToString().c_str(), nBestHeight);
//fclose(fp); // ~CAutoFile() will close the file
nRemoved++;
};
}
result.push_back(Pair("no. blocks removed", itostr(nRemoved)));
result.push_back(Pair("hashBestChain", hashBestChain.ToString()));
result.push_back(Pair("nBestHeight", itostr(nBestHeight)));
// -- need restart, setStakeSeen etc
if (nRemoved > 0)
result.push_back(Pair("Please restart Taurus", ""));
if (nRemoved == nNumber)
result.push_back(Pair("result", "success"));
else
result.push_back(Pair("result", "failure"));
return result;
}
