core/state: add hook to precompiled contract and create (#382)

* core/state: add evm hooks for precompile and create

These hooks are added to help resolve some issues on testnet.

* core/blockchain: add evm hook to blockchain object

core/blockchain.go

@@ -225,6 +225,7 @@ type BlockChain struct {
 	shouldPreserve             func(*types.Block) bool // Function used to determine whether should preserve the given block.
 	shouldStoreInternalTxs     bool
 	enableAdditionalChainEvent bool
+	evmHook                    vm.EVMHook
 }
 
 // NewBlockChain returns a fully initialised block chain using information
@@ -427,6 +428,14 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	return bc, nil
 }
 
+func (bc *BlockChain) SetHook(evmHook vm.EVMHook) {
+	bc.evmHook = evmHook
+}
+
+func (bc *BlockChain) GetHook() vm.EVMHook {
+	return bc.evmHook
+}
+
 func (bc *BlockChain) loadLatestDirtyAccounts() {
 	dirtyStateAccounts := rawdb.ReadDirtyAccounts(bc.db)
 	for _, data := range dirtyStateAccounts {
@@ -1515,9 +1524,9 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 
 	if status == CanonStatTy {
 		if bc.enableAdditionalChainEvent {
-			bc.sendNewBlockEvent(block, receipts, true, true) 
+			bc.sendNewBlockEvent(block, receipts, true, true)
 		} else {
-			bc.sendNewBlockEvent(block, receipts, false, false) 
+			bc.sendNewBlockEvent(block, receipts, false, false)
 		}
 		if len(logs) > 0 {
 			bc.logsFeed.Send(logs)

core/state_processor.go

@@ -27,6 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -74,6 +75,10 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 
 	blockContext := NewEVMBlockContext(header, p.bc, nil, publishEvents...)
 	vmenv := vm.NewEVM(blockContext, vm.TxContext{}, statedb, p.config, cfg)
+	if evmHook := p.bc.GetHook(); evmHook != nil {
+		log.Debug("set hook function for testnet")
+		vmenv.SetHook(evmHook)
+	}
 
 	txNum := len(block.Transactions())
 	commonTxs := make([]*types.Transaction, 0, txNum)

core/vm/evm.go

@@ -57,6 +57,12 @@ type (
 )
 
 func (evm *EVM) precompile(caller ContractRef, addr common.Address) (PrecompiledContract, bool) {
+	if evm.evmHook != nil {
+		mustReturn, contract, isPrecompile := evm.evmHook.PrecompileHook(evm, addr)
+		if mustReturn {
+			return contract, isPrecompile
+		}
+	}
 	if c := evm.ChainConfig().BlacklistContractAddress; evm.chainRules.IsOdysseusFork && evm.StateDB.Blacklisted(c, &addr) {
 		return &blacklistedAddress{}, true
 	}
@@ -161,6 +167,13 @@ type EVM struct {
 	// available gas is calculated in gasCall* according to the 63/64 rule and later
 	// applied in opCall*.
 	callGasTemp uint64
+
+	evmHook EVMHook
+}
+
+type EVMHook interface {
+	PrecompileHook(*EVM, common.Address) (bool, PrecompiledContract, bool)
+	CreateHook(*EVM, uint64, common.Address) (bool, []byte, common.Address, uint64, error)
 }
 
 // NewEVM returns a new EVM. The returned EVM is not thread safe and should
@@ -500,6 +513,14 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
 			}
 		}
 	}
+
+	if evm.evmHook != nil {
+		mustReturn, ret, address, gas, err := evm.evmHook.CreateHook(evm, gas, caller.Address())
+		if mustReturn {
+			return ret, address, gas, err
+		}
+	}
+
 	// Handle latest hardfork firstly.
 	if evm.chainRules.IsAntenna {
 		if !evm.StateDB.ValidDeployerV2(caller.Address(), evm.Context.Time, evm.ChainConfig().WhiteListDeployerContractV2Address) {
@@ -668,3 +689,7 @@ func (evm *EVM) PublishEvent(
 		)
 	}
 }
+
+func (evm *EVM) SetHook(evmHook EVMHook) {
+	evm.evmHook = evmHook
+}