Merge pull request ethereum#36 from OffchainLabs/callbacks-for-blockn…

…um-hash Implement NUMBER and BLOCKHASH opcodes as callbacks
joshuacolvin0 · Jan 14, 2022 · 00396ce · 00396ce
2 parents f00de6c + 686284f
commit 00396ce
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Showing 2 changed files with 24 additions and 3 deletions.
diff --git a/core/vm/evm_arbitrum.go b/core/vm/evm_arbitrum.go
@@ -16,7 +16,9 @@
 
 package vm
 
-import "github.com/ethereum/go-ethereum/common"
+import (
+	"github.com/ethereum/go-ethereum/common"
+)
 
 // Depth returns the current depth
 func (evm *EVM) Depth() int {
@@ -30,6 +32,8 @@ type TxProcessingHook interface {
 	NonrefundableGas() uint64
 	PushCaller(addr common.Address)
 	PopCaller()
+	L1BlockNumber(blockCtx BlockContext) (uint64, error)
+	L1BlockHash(blockCtx BlockContext, l1BlocKNumber uint64) (common.Hash, error)
 }
 
 type DefaultTxProcessor struct{}
@@ -57,3 +61,11 @@ func (p DefaultTxProcessor) PushCaller(addr common.Address) {
 func (p DefaultTxProcessor) PopCaller() {
 	return
 }
+
+func (p DefaultTxProcessor) L1BlockNumber(blockCtx BlockContext) (uint64, error) {
+	return blockCtx.BlockNumber.Uint64(), nil
+}
+
+func (p DefaultTxProcessor) L1BlockHash(blockCtx BlockContext, l1BlocKNumber uint64) (common.Hash, error) {
+	return blockCtx.GetHash(l1BlocKNumber), nil
+}
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
@@ -22,6 +22,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/holiman/uint256"
 	"golang.org/x/crypto/sha3"
+	"math/big"
 )
 
 func opAdd(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
@@ -445,7 +446,11 @@ func opBlockhash(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) (
 		lower = upper - 256
 	}
 	if num64 >= lower && num64 < upper {
-		num.SetBytes(interpreter.evm.Context.GetHash(num64).Bytes())
+		h, err := interpreter.evm.ProcessingHook.L1BlockHash(interpreter.evm.Context, num64)
+		if err != nil {
+			return nil, err
+		}
+		num.SetBytes(h.Bytes())
 	} else {
 		num.Clear()
 	}
@@ -464,7 +469,11 @@ func opTimestamp(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) (
 }
 
 func opNumber(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
-	v, _ := uint256.FromBig(interpreter.evm.Context.BlockNumber)
+	bnum, err := interpreter.evm.ProcessingHook.L1BlockNumber(interpreter.evm.Context)
+	if err != nil {
+		return nil, err
+	}
+	v, _ := uint256.FromBig(new(big.Int).SetUint64(bnum))
 	scope.Stack.push(v)
 	return nil, nil
 }