bsc/eth/tracers/native/prestate.go
Sina Mahmoodi 3fd16af5a9
core,eth: implement tx-level hooks for tracers (#24510)
* core,eth: add empty tx logger hooks

* core,eth: add initial and remaining gas to tx hooks

* store tx gasLimit in js tracer

* use gasLimit to compute intrinsic cost for js tracer

* re-use rules in transitiondb

* rm logs

* rm logs

* Mv some fields from Start to TxStart

* simplify sender lookup in prestate tracer

* mv env to TxStart

* Revert "mv env to TxStart"

This reverts commit 656939634b9aff19f55a1cd167345faf8b1ec310.

* Revert "simplify sender lookup in prestate tracer"

This reverts commit ab65bce48007cab99e68232e7aac2fe008338d50.

* Revert "Mv some fields from Start to TxStart"

This reverts commit aa50d3d9b2559addc80df966111ef5fb5d0c1b6b.

* fix intrinsic gas for prestate tracer

* add comments

* refactor

* fix test case

* simplify consumedGas calc in prestate tracer
2022-03-31 11:51:44 +02:00

179 lines
6.5 KiB
Go

// Copyright 2022 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package native
import (
"encoding/json"
"math/big"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/eth/tracers"
)
func init() {
register("prestateTracer", newPrestateTracer)
}
type prestate = map[common.Address]*account
type account struct {
Balance string `json:"balance"`
Nonce uint64 `json:"nonce"`
Code string `json:"code"`
Storage map[common.Hash]common.Hash `json:"storage"`
}
type prestateTracer struct {
env *vm.EVM
prestate prestate
create bool
to common.Address
gasLimit uint64 // Amount of gas bought for the whole tx
interrupt uint32 // Atomic flag to signal execution interruption
reason error // Textual reason for the interruption
}
func newPrestateTracer() tracers.Tracer {
// First callframe contains tx context info
// and is populated on start and end.
return &prestateTracer{prestate: prestate{}}
}
// CaptureStart implements the EVMLogger interface to initialize the tracing operation.
func (t *prestateTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
t.env = env
t.create = create
t.to = to
t.lookupAccount(from)
t.lookupAccount(to)
// The recipient balance includes the value transferred.
toBal := hexutil.MustDecodeBig(t.prestate[to].Balance)
toBal = new(big.Int).Sub(toBal, value)
t.prestate[to].Balance = hexutil.EncodeBig(toBal)
// The sender balance is after reducing: value and gasLimit.
// We need to re-add them to get the pre-tx balance.
fromBal := hexutil.MustDecodeBig(t.prestate[from].Balance)
gasPrice := env.TxContext.GasPrice
consumedGas := new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(t.gasLimit))
fromBal.Add(fromBal, new(big.Int).Add(value, consumedGas))
t.prestate[from].Balance = hexutil.EncodeBig(fromBal)
t.prestate[from].Nonce--
}
// CaptureEnd is called after the call finishes to finalize the tracing.
func (t *prestateTracer) CaptureEnd(output []byte, gasUsed uint64, _ time.Duration, err error) {
if t.create {
// Exclude created contract.
delete(t.prestate, t.to)
}
}
// CaptureState implements the EVMLogger interface to trace a single step of VM execution.
func (t *prestateTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
stack := scope.Stack
stackData := stack.Data()
stackLen := len(stackData)
switch {
case stackLen >= 1 && (op == vm.SLOAD || op == vm.SSTORE):
slot := common.Hash(stackData[stackLen-1].Bytes32())
t.lookupStorage(scope.Contract.Address(), slot)
case stackLen >= 1 && (op == vm.EXTCODECOPY || op == vm.EXTCODEHASH || op == vm.EXTCODESIZE || op == vm.BALANCE || op == vm.SELFDESTRUCT):
addr := common.Address(stackData[stackLen-1].Bytes20())
t.lookupAccount(addr)
case stackLen >= 5 && (op == vm.DELEGATECALL || op == vm.CALL || op == vm.STATICCALL || op == vm.CALLCODE):
addr := common.Address(stackData[stackLen-2].Bytes20())
t.lookupAccount(addr)
case op == vm.CREATE:
addr := scope.Contract.Address()
nonce := t.env.StateDB.GetNonce(addr)
t.lookupAccount(crypto.CreateAddress(addr, nonce))
case stackLen >= 4 && op == vm.CREATE2:
offset := stackData[stackLen-2]
size := stackData[stackLen-3]
init := scope.Memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
inithash := crypto.Keccak256(init)
salt := stackData[stackLen-4]
t.lookupAccount(crypto.CreateAddress2(scope.Contract.Address(), salt.Bytes32(), inithash))
}
}
// CaptureFault implements the EVMLogger interface to trace an execution fault.
func (t *prestateTracer) CaptureFault(pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
}
// CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
func (t *prestateTracer) CaptureEnter(typ vm.OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
}
// CaptureExit is called when EVM exits a scope, even if the scope didn't
// execute any code.
func (t *prestateTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
}
func (t *prestateTracer) CaptureTxStart(gasLimit uint64) {
t.gasLimit = gasLimit
}
func (t *prestateTracer) CaptureTxEnd(restGas uint64) {}
// GetResult returns the json-encoded nested list of call traces, and any
// error arising from the encoding or forceful termination (via `Stop`).
func (t *prestateTracer) GetResult() (json.RawMessage, error) {
res, err := json.Marshal(t.prestate)
if err != nil {
return nil, err
}
return json.RawMessage(res), t.reason
}
// Stop terminates execution of the tracer at the first opportune moment.
func (t *prestateTracer) Stop(err error) {
t.reason = err
atomic.StoreUint32(&t.interrupt, 1)
}
// lookupAccount fetches details of an account and adds it to the prestate
// if it doesn't exist there.
func (t *prestateTracer) lookupAccount(addr common.Address) {
if _, ok := t.prestate[addr]; ok {
return
}
t.prestate[addr] = &account{
Balance: bigToHex(t.env.StateDB.GetBalance(addr)),
Nonce: t.env.StateDB.GetNonce(addr),
Code: bytesToHex(t.env.StateDB.GetCode(addr)),
Storage: make(map[common.Hash]common.Hash),
}
}
// lookupStorage fetches the requested storage slot and adds
// it to the prestate of the given contract. It assumes `lookupAccount`
// has been performed on the contract before.
func (t *prestateTracer) lookupStorage(addr common.Address, key common.Hash) {
if _, ok := t.prestate[addr].Storage[key]; ok {
return
}
t.prestate[addr].Storage[key] = t.env.StateDB.GetState(addr, key)
}