From f834a854659d3d7e2b77ad17b4760c616ceb837c Mon Sep 17 00:00:00 2001
From: mmsqe <mavis@crypto.com>
Date: Fri, 3 Feb 2023 09:49:59 +0800
Subject: [PATCH] add CheckCaller

---
 x/evm/keeper/precompiles/bank.go  | 26 +++++---------------------
 x/evm/keeper/precompiles/utils.go | 29 +++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 21 deletions(-)
 create mode 100644 x/evm/keeper/precompiles/utils.go

diff --git a/x/evm/keeper/precompiles/bank.go b/x/evm/keeper/precompiles/bank.go
index e2f36f6961..5e0228d78d 100644
--- a/x/evm/keeper/precompiles/bank.go
+++ b/x/evm/keeper/precompiles/bank.go
@@ -3,8 +3,6 @@ package precompiles
 import (
 	"errors"
 	"math/big"
-	"runtime"
-	"strings"
 
 	sdkmath "cosmossdk.io/math"
 	"github.com/ethereum/go-ethereum/accounts/abi"
@@ -90,23 +88,9 @@ func (bc *BankContract) RequiredGas(input []byte) uint64 {
 }
 
 func (bc *BankContract) Run(input []byte) ([]byte, error) {
-	layer := 2
-	pc, _, _, _ := runtime.Caller(layer)
-	prefix := "github.com/ethereum/go-ethereum/core/vm.(*EVM)."
-	caller := runtime.FuncForPC(pc).Name()
-	readonly := false
-	if strings.Index(caller, prefix) == 0 {
-		fn := caller[len(prefix):]
-		switch fn {
-		case "Call":
-			readonly = false
-		case "CallCode":
-		case "DelegateCall":
-		case "StaticCall":
-			readonly = true
-		default:
-			return nil, errors.New("unknown caller")
-		}
+	readonly, err := CheckCaller()
+	if err != nil {
+		return nil, err
 	}
 	// parse input
 	methodID := input[:4]
@@ -147,8 +131,8 @@ func (bc *BankContract) Run(input []byte) ([]byte, error) {
 		token := args[0].(common.Address)
 		addr := args[1].(common.Address)
 		// query from storage
-		amount := bc.bankKeeper.GetBalance(bc.ctx, sdk.AccAddress(addr.Bytes()), EVMDenom(token)).Amount.BigInt()
-		return BalanceOfMethod.Outputs.Pack(amount)
+		balance := bc.bankKeeper.GetBalance(bc.ctx, sdk.AccAddress(addr.Bytes()), EVMDenom(token)).Amount.BigInt()
+		return BalanceOfMethod.Outputs.Pack(balance)
 	default:
 		return nil, errors.New("unknown method")
 	}
diff --git a/x/evm/keeper/precompiles/utils.go b/x/evm/keeper/precompiles/utils.go
new file mode 100644
index 0000000000..6e898277ed
--- /dev/null
+++ b/x/evm/keeper/precompiles/utils.go
@@ -0,0 +1,29 @@
+package precompiles
+
+import (
+	"errors"
+	"runtime"
+	"strings"
+)
+
+func CheckCaller() (bool, error) {
+	layer := 2
+	pc, _, _, _ := runtime.Caller(layer)
+	prefix := "github.com/ethereum/go-ethereum/core/vm.(*EVM)."
+	caller := runtime.FuncForPC(pc).Name()
+	readonly := false
+	if strings.Index(caller, prefix) == 0 {
+		fn := caller[len(prefix):]
+		switch fn {
+		case "Call":
+			readonly = false
+		case "CallCode":
+		case "DelegateCall":
+		case "StaticCall":
+			readonly = true
+		default:
+			return readonly, errors.New("unknown caller")
+		}
+	}
+	return readonly, nil
+}