From 99f76847ba8091ce1b8b894710961ff6336a39bd Mon Sep 17 00:00:00 2001
From: beer-1 <beer-1@codingcats.xyz>
Date: Wed, 13 Nov 2024 19:25:28 +0900
Subject: [PATCH] introduce lock

---
 jsonrpc/backend/backend.go | 14 ++++++++++++++
 jsonrpc/backend/eth.go     |  9 +++++----
 jsonrpc/backend/gas.go     | 29 ++++++++++++++++++++---------
 3 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/jsonrpc/backend/backend.go b/jsonrpc/backend/backend.go
index 5362ebe..bcf0b37 100644
--- a/jsonrpc/backend/backend.go
+++ b/jsonrpc/backend/backend.go
@@ -43,6 +43,7 @@ type JSONRPCBackend struct {
 	// fee cache
 	feeDenom    string
 	feeDecimals uint8
+	feeMutex    sync.RWMutex
 
 	mut     sync.Mutex // mutex for accMuts
 	accMuts map[string]*AccMut
@@ -126,6 +127,17 @@ func NewJSONRPCBackend(
 	return b, nil
 }
 
+func (b *JSONRPCBackend) feeInfo() (string, uint8, error) {
+	b.feeMutex.RLock()
+	defer b.feeMutex.RUnlock()
+
+	if b.feeDenom == "" {
+		return "", 0, NewInternalError("jsonrpc is not ready")
+	}
+
+	return b.feeDenom, b.feeDecimals, nil
+}
+
 func (b *JSONRPCBackend) feeFetcher() {
 	fetcher := func() (err error) {
 		defer func() {
@@ -150,8 +162,10 @@ func (b *JSONRPCBackend) feeFetcher() {
 			return err
 		}
 
+		b.feeMutex.Lock()
 		b.feeDenom = feeDenom
 		b.feeDecimals = decimals
+		b.feeMutex.Unlock()
 
 		return nil
 	}
diff --git a/jsonrpc/backend/eth.go b/jsonrpc/backend/eth.go
index 41ff3d4..8f48e2f 100644
--- a/jsonrpc/backend/eth.go
+++ b/jsonrpc/backend/eth.go
@@ -26,16 +26,17 @@ func (b *JSONRPCBackend) GetBalance(address common.Address, blockNrOrHash rpc.Bl
 	}
 
 	// jsonrpc is not ready for querying
-	if b.feeDenom == "" {
-		return nil, errors.New("jsonrpc is not ready")
+	feeDenom, feeDecimals, err := b.feeInfo()
+	if err != nil {
+		return nil, err
 	}
 
-	balance, err := b.app.EVMKeeper.ERC20Keeper().GetBalance(queryCtx, sdk.AccAddress(address[:]), b.feeDenom)
+	balance, err := b.app.EVMKeeper.ERC20Keeper().GetBalance(queryCtx, sdk.AccAddress(address[:]), feeDenom)
 	if err != nil {
 		return nil, err
 	}
 
-	return (*hexutil.Big)(types.ToEthersUint(b.feeDecimals, balance.BigInt())), nil
+	return (*hexutil.Big)(types.ToEthersUint(feeDecimals, balance.BigInt())), nil
 }
 
 func (b *JSONRPCBackend) Call(args rpctypes.TransactionArgs, blockNrOrHash *rpc.BlockNumberOrHash, overrides *rpctypes.StateOverride, blockOverrides *rpctypes.BlockOverrides) (hexutil.Bytes, error) {
diff --git a/jsonrpc/backend/gas.go b/jsonrpc/backend/gas.go
index fe6e5e5..edf2022 100644
--- a/jsonrpc/backend/gas.go
+++ b/jsonrpc/backend/gas.go
@@ -40,8 +40,9 @@ func (b *JSONRPCBackend) EstimateGas(args rpctypes.TransactionArgs, blockNrOrHas
 	}
 
 	// jsonrpc is not ready for querying
-	if b.feeDenom == "" {
-		return hexutil.Uint64(0), NewInternalError("jsonrpc is not ready")
+	_, feeDecimals, err := b.feeInfo()
+	if err != nil {
+		return hexutil.Uint64(0), err
 	}
 
 	sdkMsgs := []sdk.Msg{}
@@ -49,14 +50,14 @@ func (b *JSONRPCBackend) EstimateGas(args rpctypes.TransactionArgs, blockNrOrHas
 		sdkMsgs = append(sdkMsgs, &types.MsgCreate{
 			Sender: sender,
 			Code:   hexutil.Encode(args.GetData()),
-			Value:  math.NewIntFromBigInt(types.FromEthersUnit(b.feeDecimals, args.Value.ToInt())),
+			Value:  math.NewIntFromBigInt(types.FromEthersUnit(feeDecimals, args.Value.ToInt())),
 		})
 	} else {
 		sdkMsgs = append(sdkMsgs, &types.MsgCall{
 			Sender:       sender,
 			ContractAddr: args.To.Hex(),
 			Input:        hexutil.Encode(args.GetData()),
-			Value:        math.NewIntFromBigInt(types.FromEthersUnit(b.feeDecimals, args.Value.ToInt())),
+			Value:        math.NewIntFromBigInt(types.FromEthersUnit(feeDecimals, args.Value.ToInt())),
 		})
 	}
 
@@ -102,16 +103,26 @@ func (b *JSONRPCBackend) GasPrice() (*hexutil.Big, error) {
 	}
 
 	// jsonrpc is not ready for querying
-	if b.feeDenom == "" {
-		return nil, NewInternalError("jsonrpc is not ready")
+	feeDenom, feeDecimals, err := b.feeInfo()
+	if err != nil {
+		return nil, err
 	}
 
+	// Multiply by 1e9 to maintain precision during conversion
+	// This adds 9 decimal places to prevent truncation errors
+	const precisionMultiplier = 1e9
+
 	// multiply by 1e9 to prevent decimal drops
-	gasPrice := params.MinGasPrices.AmountOf(b.feeDenom).
-		MulTruncate(math.LegacyNewDec(1e9)).
+	gasPrice := params.MinGasPrices.AmountOf(feeDenom).
+		MulTruncate(math.LegacyNewDec(precisionMultiplier)).
 		TruncateInt().BigInt()
 
-	return (*hexutil.Big)(types.ToEthersUint(b.feeDecimals+9, gasPrice)), nil
+	// Verify the result is within safe bounds
+	if gasPrice.BitLen() > 256 {
+		return nil, NewInternalError("gas price overflow")
+	}
+
+	return (*hexutil.Big)(types.ToEthersUint(feeDecimals+9, gasPrice)), nil
 }
 
 func (b *JSONRPCBackend) MaxPriorityFeePerGas() (*hexutil.Big, error) {