go-ethereum/eth/tracers/native/prestate.go
Martin HS a5a4fa7032
all: use uint256 in state (#28598)
This change makes use of uin256 to represent balance in state. It touches primarily upon statedb, stateobject and state processing, trying to avoid changes in transaction pools, core types, rpc and tracers.
2024-01-23 14:51:58 +01:00

298 lines
8.9 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 (
"bytes"
"encoding/json"
"math/big"
"sync/atomic"
"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"
"github.com/ethereum/go-ethereum/log"
)
//go:generate go run github.com/fjl/gencodec -type account -field-override accountMarshaling -out gen_account_json.go
func init() {
tracers.DefaultDirectory.Register("prestateTracer", newPrestateTracer, false)
}
type state = map[common.Address]*account
type account struct {
Balance *big.Int `json:"balance,omitempty"`
Code []byte `json:"code,omitempty"`
Nonce uint64 `json:"nonce,omitempty"`
Storage map[common.Hash]common.Hash `json:"storage,omitempty"`
}
func (a *account) exists() bool {
return a.Nonce > 0 || len(a.Code) > 0 || len(a.Storage) > 0 || (a.Balance != nil && a.Balance.Sign() != 0)
}
type accountMarshaling struct {
Balance *hexutil.Big
Code hexutil.Bytes
}
type prestateTracer struct {
noopTracer
env *vm.EVM
pre state
post state
create bool
to common.Address
gasLimit uint64 // Amount of gas bought for the whole tx
config prestateTracerConfig
interrupt atomic.Bool // Atomic flag to signal execution interruption
reason error // Textual reason for the interruption
created map[common.Address]bool
deleted map[common.Address]bool
}
type prestateTracerConfig struct {
DiffMode bool `json:"diffMode"` // If true, this tracer will return state modifications
}
func newPrestateTracer(ctx *tracers.Context, cfg json.RawMessage) (tracers.Tracer, error) {
var config prestateTracerConfig
if cfg != nil {
if err := json.Unmarshal(cfg, &config); err != nil {
return nil, err
}
}
return &prestateTracer{
pre: state{},
post: state{},
config: config,
created: make(map[common.Address]bool),
deleted: make(map[common.Address]bool),
}, nil
}
// 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)
t.lookupAccount(env.Context.Coinbase)
// The recipient balance includes the value transferred.
toBal := new(big.Int).Sub(t.pre[to].Balance, value)
t.pre[to].Balance = toBal
// The sender balance is after reducing: value and gasLimit.
// We need to re-add them to get the pre-tx balance.
fromBal := new(big.Int).Set(t.pre[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.pre[from].Balance = fromBal
t.pre[from].Nonce--
if create && t.config.DiffMode {
t.created[to] = true
}
}
// CaptureEnd is called after the call finishes to finalize the tracing.
func (t *prestateTracer) CaptureEnd(output []byte, gasUsed uint64, err error) {
if t.config.DiffMode {
return
}
if t.create {
// Keep existing account prior to contract creation at that address
if s := t.pre[t.to]; s != nil && !s.exists() {
// Exclude newly created contract.
delete(t.pre, 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) {
if err != nil {
return
}
// Skip if tracing was interrupted
if t.interrupt.Load() {
return
}
stack := scope.Stack
stackData := stack.Data()
stackLen := len(stackData)
caller := scope.Contract.Address()
switch {
case stackLen >= 1 && (op == vm.SLOAD || op == vm.SSTORE):
slot := common.Hash(stackData[stackLen-1].Bytes32())
t.lookupStorage(caller, 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)
if op == vm.SELFDESTRUCT {
t.deleted[caller] = true
}
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:
nonce := t.env.StateDB.GetNonce(caller)
addr := crypto.CreateAddress(caller, nonce)
t.lookupAccount(addr)
t.created[addr] = true
case stackLen >= 4 && op == vm.CREATE2:
offset := stackData[stackLen-2]
size := stackData[stackLen-3]
init, err := tracers.GetMemoryCopyPadded(scope.Memory, int64(offset.Uint64()), int64(size.Uint64()))
if err != nil {
log.Warn("failed to copy CREATE2 input", "err", err, "tracer", "prestateTracer", "offset", offset, "size", size)
return
}
inithash := crypto.Keccak256(init)
salt := stackData[stackLen-4]
addr := crypto.CreateAddress2(caller, salt.Bytes32(), inithash)
t.lookupAccount(addr)
t.created[addr] = true
}
}
func (t *prestateTracer) CaptureTxStart(gasLimit uint64) {
t.gasLimit = gasLimit
}
func (t *prestateTracer) CaptureTxEnd(restGas uint64) {
if !t.config.DiffMode {
return
}
for addr, state := range t.pre {
// The deleted account's state is pruned from `post` but kept in `pre`
if _, ok := t.deleted[addr]; ok {
continue
}
modified := false
postAccount := &account{Storage: make(map[common.Hash]common.Hash)}
newBalance := t.env.StateDB.GetBalance(addr).ToBig()
newNonce := t.env.StateDB.GetNonce(addr)
newCode := t.env.StateDB.GetCode(addr)
if newBalance.Cmp(t.pre[addr].Balance) != 0 {
modified = true
postAccount.Balance = newBalance
}
if newNonce != t.pre[addr].Nonce {
modified = true
postAccount.Nonce = newNonce
}
if !bytes.Equal(newCode, t.pre[addr].Code) {
modified = true
postAccount.Code = newCode
}
for key, val := range state.Storage {
// don't include the empty slot
if val == (common.Hash{}) {
delete(t.pre[addr].Storage, key)
}
newVal := t.env.StateDB.GetState(addr, key)
if val == newVal {
// Omit unchanged slots
delete(t.pre[addr].Storage, key)
} else {
modified = true
if newVal != (common.Hash{}) {
postAccount.Storage[key] = newVal
}
}
}
if modified {
t.post[addr] = postAccount
} else {
// if state is not modified, then no need to include into the pre state
delete(t.pre, addr)
}
}
// the new created contracts' prestate were empty, so delete them
for a := range t.created {
// the created contract maybe exists in statedb before the creating tx
if s := t.pre[a]; s != nil && !s.exists() {
delete(t.pre, a)
}
}
}
// 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) {
var res []byte
var err error
if t.config.DiffMode {
res, err = json.Marshal(struct {
Post state `json:"post"`
Pre state `json:"pre"`
}{t.post, t.pre})
} else {
res, err = json.Marshal(t.pre)
}
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
t.interrupt.Store(true)
}
// 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.pre[addr]; ok {
return
}
t.pre[addr] = &account{
Balance: t.env.StateDB.GetBalance(addr).ToBig(),
Nonce: t.env.StateDB.GetNonce(addr),
Code: 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.pre[addr].Storage[key]; ok {
return
}
t.pre[addr].Storage[key] = t.env.StateDB.GetState(addr, key)
}