Accept alternative nonce.

eth/main.cpp

@@ -116,6 +116,7 @@ void help()
 #endif
 		<< "    -K,--kill  First kill the blockchain." << endl
 		<< "    -R,--rebuild  Rebuild the blockchain from the existing database." << endl
+		<< "    --genesis-nonce <nonce>  Set the Genesis Nonce to the given hex nonce." << endl
 		<< "    -s,--import-secret <secret>  Import a secret key into the key store and use as the default." << endl
 		<< "    -S,--import-session-secret <secret>  Import a secret key into the key store and use as the default for this session only." << endl
 		<< "    --sign-key <address>  Sign all transactions with the key of the given address." << endl
@@ -468,6 +469,18 @@ int main(int argc, char** argv)
 		}
 		else if ((arg == "-d" || arg == "--path" || arg == "--db-path") && i + 1 < argc)
 			dbPath = argv[++i];
+		else if (arg == "--genesis-nonce" && i + 1 < argc)
+		{
+			try
+			{
+				CanonBlockChain::setGenesisNonce(Nonce(argv[++i]));
+			}
+			catch (...)
+			{
+				cerr << "Bad " << arg << " option: " << argv[i] << endl;
+				return -1;
+			}
+		}
 /*		else if ((arg == "-B" || arg == "--block-fees") && i + 1 < argc)
 		{
 			try

libethereum/CanonBlockChain.cpp

@@ -72,6 +72,7 @@ std::unordered_map<Address, Account> const& dev::eth::genesisState()
 
 std::unique_ptr<BlockInfo> CanonBlockChain::s_genesis;
 boost::shared_mutex CanonBlockChain::x_genesis;
+Nonce CanonBlockChain::s_nonce(u64(42));
 
 bytes CanonBlockChain::createGenesisBlock()
 {
@@ -87,12 +88,33 @@ bytes CanonBlockChain::createGenesisBlock()
 	}
 
 	block.appendList(15)
-			<< h256() << EmptyListSHA3 << h160() << stateRoot << EmptyTrie << EmptyTrie << LogBloom() << c_genesisDifficulty << 0 << c_genesisGasLimit << 0 << (unsigned)0 << string() << h256() << Nonce(u64(42));
+			<< h256() << EmptyListSHA3 << h160() << stateRoot << EmptyTrie << EmptyTrie << LogBloom() << c_genesisDifficulty << 0 << c_genesisGasLimit << 0 << (unsigned)0 << string() << h256() << s_nonce;
 	block.appendRaw(RLPEmptyList);
 	block.appendRaw(RLPEmptyList);
 	return block.out();
 }
 
-CanonBlockChain::CanonBlockChain(std::string const& _path, WithExisting _we, ProgressCallback const& _pc): BlockChain(CanonBlockChain::createGenesisBlock(), _path, _we, _pc)
+CanonBlockChain::CanonBlockChain(std::string const& _path, WithExisting _we, ProgressCallback const& _pc):
+	BlockChain(createGenesisBlock(), _path, _we, _pc)
 {
 }
+
+void CanonBlockChain::setGenesisNonce(Nonce const& _n)
+{
+	WriteGuard l(x_genesis);
+	s_nonce = _n;
+	s_genesis.reset();
+}
+
+BlockInfo const& CanonBlockChain::genesis()
+{
+	UpgradableGuard l(x_genesis);
+	if (!s_genesis)
+	{
+		auto gb = createGenesisBlock();
+		UpgradeGuard ul(l);
+		s_genesis.reset(new BlockInfo);
+		s_genesis->populate(&gb);
+	}
+	return *s_genesis;
+}

libethereum/CanonBlockChain.h

@@ -59,16 +59,22 @@ public:
 	~CanonBlockChain() {}
 
 	/// @returns the genesis block header.
-		static BlockInfo const& genesis() { UpgradableGuard l(x_genesis); if (!s_genesis) { auto gb = createGenesisBlock(); UpgradeGuard ul(l); s_genesis.reset(new BlockInfo); s_genesis->populate(&gb); } return *s_genesis; }
+	static BlockInfo const& genesis();
 
 	/// @returns the genesis block as its RLP-encoded byte array.
 	/// @note This is slow as it's constructed anew each call. Consider genesis() instead.
 	static bytes createGenesisBlock();
 
+	/// Alter the value of the genesis block's nonce.
+	/// @warning Unless you're very careful, make sure you call this right at the start of the
+	/// program, before anything has had the chance to use this class at all.
+	static void setGenesisNonce(Nonce const& _n);
+
 private:
 	/// Static genesis info and its lock.
 	static boost::shared_mutex x_genesis;
 	static std::unique_ptr<BlockInfo> s_genesis;
+	static Nonce s_nonce;
 };
 
 }

libethereum/Client.cpp

@@ -47,8 +47,11 @@ VersionChecker::VersionChecker(string const& _dbPath):
 		(void)protocolVersion;
 		auto minorProtocolVersion = (unsigned)status[1];
 		auto databaseVersion = (unsigned)status[2];
+		h256 ourGenesisHash = CanonBlockChain::genesis().hash();
+		auto genesisHash = status.itemCount() > 3 ? (h256)status[3] : ourGenesisHash;
+
 		m_action =
-			databaseVersion != c_databaseVersion ?
+			databaseVersion != c_databaseVersion || genesisHash != ourGenesisHash ?
 				WithExisting::Kill
 			: minorProtocolVersion != eth::c_minorProtocolVersion ?
 				WithExisting::Verify
@@ -73,7 +76,7 @@ void VersionChecker::setOk()
 		{
 			cwarn << "Unhandled exception! Failed to create directory: " << m_path << "\n" << boost::current_exception_diagnostic_information();
 		}
-		writeFile(m_path + "/status", rlpList(eth::c_protocolVersion, eth::c_minorProtocolVersion, c_databaseVersion));
+		writeFile(m_path + "/status", rlpList(eth::c_protocolVersion, eth::c_minorProtocolVersion, c_databaseVersion, CanonBlockChain::genesis().hash()));
 	}
 }