From e01a0f26195b276385a716863fd607a16285e24b Mon Sep 17 00:00:00 2001
From: Ferran <ferranbt@protonmail.com>
Date: Mon, 9 May 2022 17:39:07 +0400
Subject: [PATCH] Limit state sync by gas

---
 consensus/bor/bor.go                      | 22 +++++++++++++++++-----
 consensus/bor/genesis_contracts_client.go | 13 +++++++------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/consensus/bor/bor.go b/consensus/bor/bor.go
index 2623011d79..70e45bab22 100644
--- a/consensus/bor/bor.go
+++ b/consensus/bor/bor.go
@@ -1144,7 +1144,8 @@ func (c *Bor) fetchAndCommitSpan(
 	msg := getSystemMessage(common.HexToAddress(c.config.ValidatorContract), data)
 
 	// apply message
-	return applyMessage(msg, state, header, c.chainConfig, chain)
+	_, err = applyMessage(msg, state, header, c.chainConfig, chain)
+	return err
 }
 
 // CommitStates commit states
@@ -1173,6 +1174,8 @@ func (c *Bor) CommitStates(
 		}
 	}
 
+	totalGas := 10000000 /// limit on gas for state sync per block
+
 	chainID := c.chainConfig.ChainID.String()
 	for _, eventRecord := range eventRecords {
 		if eventRecord.ID <= lastStateID {
@@ -1191,9 +1194,15 @@ func (c *Bor) CommitStates(
 		}
 		stateSyncs = append(stateSyncs, &stateData)
 
-		if err := c.GenesisContractsClient.CommitState(eventRecord, state, header, chain); err != nil {
+		gasUsed, err := c.GenesisContractsClient.CommitState(eventRecord, state, header, chain)
+		if err != nil {
 			return nil, err
 		}
+		totalGas -= int(gasUsed)
+		if totalGas < 0 {
+			break
+		}
+
 		lastStateID++
 	}
 	return stateSyncs, nil
@@ -1311,14 +1320,16 @@ func applyMessage(
 	header *types.Header,
 	chainConfig *params.ChainConfig,
 	chainContext core.ChainContext,
-) error {
+) (uint64, error) {
+	initialGas := msg.Gas()
+
 	// Create a new context to be used in the EVM environment
 	blockContext := core.NewEVMBlockContext(header, chainContext, &header.Coinbase)
 	// Create a new environment which holds all relevant information
 	// about the transaction and calling mechanisms.
 	vmenv := vm.NewEVM(blockContext, vm.TxContext{}, state, chainConfig, vm.Config{})
 	// Apply the transaction to the current state (included in the env)
-	_, _, err := vmenv.Call(
+	_, gasLeft, err := vmenv.Call(
 		vm.AccountRef(msg.From()),
 		*msg.To(),
 		msg.Data(),
@@ -1330,7 +1341,8 @@ func applyMessage(
 		state.Finalise(true)
 	}
 
-	return nil
+	gasUsed := initialGas - gasLeft
+	return gasUsed, nil
 }
 
 func validatorContains(a []*Validator, x *Validator) (*Validator, bool) {
diff --git a/consensus/bor/genesis_contracts_client.go b/consensus/bor/genesis_contracts_client.go
index 582358e0cb..456e3fe2e5 100644
--- a/consensus/bor/genesis_contracts_client.go
+++ b/consensus/bor/genesis_contracts_client.go
@@ -53,25 +53,26 @@ func (gc *GenesisContractsClient) CommitState(
 	state *state.StateDB,
 	header *types.Header,
 	chCtx chainContext,
-) error {
+) (uint64, error) {
 	eventRecord := event.BuildEventRecord()
 	recordBytes, err := rlp.EncodeToBytes(eventRecord)
 	if err != nil {
-		return err
+		return 0, err
 	}
 	method := "commitState"
 	t := event.Time.Unix()
 	data, err := gc.stateReceiverABI.Pack(method, big.NewInt(0).SetInt64(t), recordBytes)
 	if err != nil {
 		log.Error("Unable to pack tx for commitState", "error", err)
-		return err
+		return 0, err
 	}
 	log.Info("→ committing new state", "eventRecord", event.String())
 	msg := getSystemMessage(common.HexToAddress(gc.StateReceiverContract), data)
-	if err := applyMessage(msg, state, header, gc.chainConfig, chCtx); err != nil {
-		return err
+	gasUsed, err := applyMessage(msg, state, header, gc.chainConfig, chCtx)
+	if err != nil {
+		return 0, err
 	}
-	return nil
+	return gasUsed, nil
 }
 
 func (gc *GenesisContractsClient) LastStateId(snapshotNumber uint64) (*big.Int, error) {