core: settable genesis nonce

You can set the nonce of the block with `--genesisnonce`. When the
genesis nonce changes and it doesn't match with the first block in your
database it will fail. A new `datadir` must be given if the nonce of the
genesis block changes.

core/block_processor_test.go

@@ -1,6 +1,7 @@
 package core
 
 import (
+	"fmt"
 	"math/big"
 	"testing"
 
@@ -16,7 +17,11 @@ func proc() (*BlockProcessor, *ChainManager) {
 	db, _ := ethdb.NewMemDatabase()
 	var mux event.TypeMux
 
-	chainMan := NewChainManager(db, db, thePow(), &mux)
+	genesis := GenesisBlock(0, db)
+	chainMan, err := NewChainManager(genesis, db, db, thePow(), &mux)
+	if err != nil {
+		fmt.Println(err)
+	}
 	return NewBlockProcessor(db, db, ezp.New(), chainMan, &mux), chainMan
 }
 

core/chain_makers.go

@@ -108,7 +108,7 @@ func makeChain(bman *BlockProcessor, parent *types.Block, max int, db common.Dat
 // Create a new chain manager starting from given block
 // Effectively a fork factory
 func newChainManager(block *types.Block, eventMux *event.TypeMux, db common.Database) *ChainManager {
-	genesis := GenesisBlock(db)
+	genesis := GenesisBlock(0, db)
 	bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: eventMux, pow: FakePow{}}
 	bc.txState = state.ManageState(state.New(genesis.Root(), db))
 	bc.futureBlocks = NewBlockCache(1000)

core/chain_manager.go

@@ -109,16 +109,22 @@ type ChainManager struct {
 	pow pow.PoW
 }
 
-func NewChainManager(blockDb, stateDb common.Database, pow pow.PoW, mux *event.TypeMux) *ChainManager {
+func NewChainManager(genesis *types.Block, blockDb, stateDb common.Database, pow pow.PoW, mux *event.TypeMux) (*ChainManager, error) {
 	bc := &ChainManager{
-		blockDb:      blockDb,
-		stateDb:      stateDb,
-		genesisBlock: GenesisBlock(stateDb),
-		eventMux:     mux,
-		quit:         make(chan struct{}),
-		cache:        NewBlockCache(blockCacheLimit),
-		pow:          pow,
+		blockDb:  blockDb,
+		stateDb:  stateDb,
+		eventMux: mux,
+		quit:     make(chan struct{}),
+		cache:    NewBlockCache(blockCacheLimit),
+		pow:      pow,
 	}
+
+	// Check the genesis block given to the chain manager. If the genesis block mismatches block number 0
+	// throw an error. If no block or the same block's found continue.
+	if g := bc.GetBlockByNumber(0); g != nil && g.Hash() != genesis.Hash() {
+		return nil, fmt.Errorf("Genesis mismatch. Maybe different nonce (%d vs %d)? %x / %x", g.Nonce(), genesis.Nonce(), g.Hash().Bytes()[:4], genesis.Hash().Bytes()[:4])
+	}
+	bc.genesisBlock = genesis
 	bc.setLastState()
 
 	// Check the current state of the block hashes and make sure that we do not have any of the bad blocks in our chain
@@ -144,7 +150,7 @@ func NewChainManager(blockDb, stateDb common.Database, pow pow.PoW, mux *event.T
 
 	go bc.update()
 
-	return bc
+	return bc, nil
 }
 
 func (bc *ChainManager) SetHead(head *types.Block) {

core/chain_manager_test.go

@@ -29,6 +29,21 @@ func thePow() pow.PoW {
 	return pow
 }
 
+func theChainManager(db common.Database, t *testing.T) *ChainManager {
+	var eventMux event.TypeMux
+	genesis := GenesisBlock(0, db)
+	chainMan, err := NewChainManager(genesis, db, db, thePow(), &eventMux)
+	if err != nil {
+		t.Error("failed creating chainmanager:", err)
+		t.FailNow()
+		return nil
+	}
+	blockMan := NewBlockProcessor(db, db, nil, chainMan, &eventMux)
+	chainMan.SetProcessor(blockMan)
+
+	return chainMan
+}
+
 // Test fork of length N starting from block i
 func testFork(t *testing.T, bman *BlockProcessor, i, N int, f func(td1, td2 *big.Int)) {
 	// switch databases to process the new chain
@@ -266,10 +281,7 @@ func TestChainInsertions(t *testing.T) {
 		t.FailNow()
 	}
 
-	var eventMux event.TypeMux
-	chainMan := NewChainManager(db, db, thePow(), &eventMux)
-	blockMan := NewBlockProcessor(db, db, nil, chainMan, &eventMux)
-	chainMan.SetProcessor(blockMan)
+	chainMan := theChainManager(db, t)
 
 	const max = 2
 	done := make(chan bool, max)
@@ -311,10 +323,9 @@ func TestChainMultipleInsertions(t *testing.T) {
 			t.FailNow()
 		}
 	}
-	var eventMux event.TypeMux
-	chainMan := NewChainManager(db, db, thePow(), &eventMux)
-	blockMan := NewBlockProcessor(db, db, nil, chainMan, &eventMux)
-	chainMan.SetProcessor(blockMan)
+
+	chainMan := theChainManager(db, t)
+
 	done := make(chan bool, max)
 	for i, chain := range chains {
 		// XXX the go routine would otherwise reference the same (chain[3]) variable and fail
@@ -339,8 +350,7 @@ func TestGetAncestors(t *testing.T) {
 	t.Skip() // travil fails.
 
 	db, _ := ethdb.NewMemDatabase()
-	var eventMux event.TypeMux
-	chainMan := NewChainManager(db, db, thePow(), &eventMux)
+	chainMan := theChainManager(db, t)
 	chain, err := loadChain("valid1", t)
 	if err != nil {
 		fmt.Println(err)
@@ -391,7 +401,7 @@ func chm(genesis *types.Block, db common.Database) *ChainManager {
 func TestReorgLongest(t *testing.T) {
 	t.Skip("skipped while cache is removed")
 	db, _ := ethdb.NewMemDatabase()
-	genesis := GenesisBlock(db)
+	genesis := GenesisBlock(0, db)
 	bc := chm(genesis, db)
 
 	chain1 := makeChainWithDiff(genesis, []int{1, 2, 4}, 10)
@@ -411,7 +421,7 @@ func TestReorgLongest(t *testing.T) {
 func TestReorgShortest(t *testing.T) {
 	t.Skip("skipped while cache is removed")
 	db, _ := ethdb.NewMemDatabase()
-	genesis := GenesisBlock(db)
+	genesis := GenesisBlock(0, db)
 	bc := chm(genesis, db)
 
 	chain1 := makeChainWithDiff(genesis, []int{1, 2, 3, 4}, 10)
@@ -431,7 +441,7 @@ func TestReorgShortest(t *testing.T) {
 func TestInsertNonceError(t *testing.T) {
 	for i := 1; i < 25 && !t.Failed(); i++ {
 		db, _ := ethdb.NewMemDatabase()
-		genesis := GenesisBlock(db)
+		genesis := GenesisBlock(0, db)
 		bc := chm(genesis, db)
 		bc.processor = NewBlockProcessor(db, db, bc.pow, bc, bc.eventMux)
 		blocks := makeChain(bc.processor.(*BlockProcessor), bc.currentBlock, i, db, 0)
@@ -465,6 +475,21 @@ func TestInsertNonceError(t *testing.T) {
 	}
 }
 
+func TestGenesisMismatch(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+	var mux event.TypeMux
+	genesis := GenesisBlock(0, db)
+	_, err := NewChainManager(genesis, db, db, thePow(), &mux)
+	if err != nil {
+		t.Error(err)
+	}
+	genesis = GenesisBlock(1, db)
+	_, err = NewChainManager(genesis, db, db, thePow(), &mux)
+	if err == nil {
+		t.Error("expected genesis mismatch error")
+	}
+}
+
 // failpow returns false from Verify for a certain block number.
 type failpow struct{ num uint64 }
 

core/genesis.go

@@ -19,8 +19,8 @@ var ZeroHash256 = make([]byte, 32)
 var ZeroHash160 = make([]byte, 20)
 var ZeroHash512 = make([]byte, 64)
 
-func GenesisBlock(db common.Database) *types.Block {
-	genesis := types.NewBlock(common.Hash{}, common.Address{}, common.Hash{}, params.GenesisDifficulty, 42, nil)
+func GenesisBlock(nonce uint64, db common.Database) *types.Block {
+	genesis := types.NewBlock(common.Hash{}, common.Address{}, common.Hash{}, params.GenesisDifficulty, nonce, nil)
 	genesis.Header().Number = common.Big0
 	genesis.Header().GasLimit = params.GenesisGasLimit
 	genesis.Header().GasUsed = common.Big0