plugeth/eth/tracers/api.go
Martin Holst Swende 3531ca2246
eth/tracers: avoid unsyncronized mutations on trie database (#23632)
This PR fixes an issue in traceChain, where the statedb Commit operation was performed asynchronously with dereference-operations agains the underlying trie.Database instance. Due to how the reference counting works within the trie database (where parent count is recursively updated when new parents are added), doing dereferencing in the middle of Commit can cause the refcount to become wrong, leading to an inconsistent state. 

This was fixed by doing Commit/Deref from the same routine.
2021-09-28 13:06:19 +02:00

927 lines
32 KiB
Go

// Copyright 2021 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 tracers
import (
"bufio"
"bytes"
"context"
"errors"
"fmt"
"io/ioutil"
"os"
"runtime"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/consensus"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/rpc"
)
const (
// defaultTraceTimeout is the amount of time a single transaction can execute
// by default before being forcefully aborted.
defaultTraceTimeout = 5 * time.Second
// defaultTraceReexec is the number of blocks the tracer is willing to go back
// and reexecute to produce missing historical state necessary to run a specific
// trace.
defaultTraceReexec = uint64(128)
)
// Backend interface provides the common API services (that are provided by
// both full and light clients) with access to necessary functions.
type Backend interface {
HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error)
BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
GetTransaction(ctx context.Context, txHash common.Hash) (*types.Transaction, common.Hash, uint64, uint64, error)
RPCGasCap() uint64
ChainConfig() *params.ChainConfig
Engine() consensus.Engine
ChainDb() ethdb.Database
StateAtBlock(ctx context.Context, block *types.Block, reexec uint64, base *state.StateDB, checkLive bool) (*state.StateDB, error)
StateAtTransaction(ctx context.Context, block *types.Block, txIndex int, reexec uint64) (core.Message, vm.BlockContext, *state.StateDB, error)
}
// API is the collection of tracing APIs exposed over the private debugging endpoint.
type API struct {
backend Backend
}
// NewAPI creates a new API definition for the tracing methods of the Ethereum service.
func NewAPI(backend Backend) *API {
return &API{backend: backend}
}
type chainContext struct {
api *API
ctx context.Context
}
func (context *chainContext) Engine() consensus.Engine {
return context.api.backend.Engine()
}
func (context *chainContext) GetHeader(hash common.Hash, number uint64) *types.Header {
header, err := context.api.backend.HeaderByNumber(context.ctx, rpc.BlockNumber(number))
if err != nil {
return nil
}
if header.Hash() == hash {
return header
}
header, err = context.api.backend.HeaderByHash(context.ctx, hash)
if err != nil {
return nil
}
return header
}
// chainContext construts the context reader which is used by the evm for reading
// the necessary chain context.
func (api *API) chainContext(ctx context.Context) core.ChainContext {
return &chainContext{api: api, ctx: ctx}
}
// blockByNumber is the wrapper of the chain access function offered by the backend.
// It will return an error if the block is not found.
func (api *API) blockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error) {
block, err := api.backend.BlockByNumber(ctx, number)
if err != nil {
return nil, err
}
if block == nil {
return nil, fmt.Errorf("block #%d not found", number)
}
return block, nil
}
// blockByHash is the wrapper of the chain access function offered by the backend.
// It will return an error if the block is not found.
func (api *API) blockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
block, err := api.backend.BlockByHash(ctx, hash)
if err != nil {
return nil, err
}
if block == nil {
return nil, fmt.Errorf("block %s not found", hash.Hex())
}
return block, nil
}
// blockByNumberAndHash is the wrapper of the chain access function offered by
// the backend. It will return an error if the block is not found.
//
// Note this function is friendly for the light client which can only retrieve the
// historical(before the CHT) header/block by number.
func (api *API) blockByNumberAndHash(ctx context.Context, number rpc.BlockNumber, hash common.Hash) (*types.Block, error) {
block, err := api.blockByNumber(ctx, number)
if err != nil {
return nil, err
}
if block.Hash() == hash {
return block, nil
}
return api.blockByHash(ctx, hash)
}
// TraceConfig holds extra parameters to trace functions.
type TraceConfig struct {
*vm.LogConfig
Tracer *string
Timeout *string
Reexec *uint64
}
// TraceCallConfig is the config for traceCall API. It holds one more
// field to override the state for tracing.
type TraceCallConfig struct {
*vm.LogConfig
Tracer *string
Timeout *string
Reexec *uint64
StateOverrides *ethapi.StateOverride
}
// StdTraceConfig holds extra parameters to standard-json trace functions.
type StdTraceConfig struct {
vm.LogConfig
Reexec *uint64
TxHash common.Hash
}
// txTraceResult is the result of a single transaction trace.
type txTraceResult struct {
Result interface{} `json:"result,omitempty"` // Trace results produced by the tracer
Error string `json:"error,omitempty"` // Trace failure produced by the tracer
}
// blockTraceTask represents a single block trace task when an entire chain is
// being traced.
type blockTraceTask struct {
statedb *state.StateDB // Intermediate state prepped for tracing
block *types.Block // Block to trace the transactions from
rootref common.Hash // Trie root reference held for this task
results []*txTraceResult // Trace results procudes by the task
}
// blockTraceResult represets the results of tracing a single block when an entire
// chain is being traced.
type blockTraceResult struct {
Block hexutil.Uint64 `json:"block"` // Block number corresponding to this trace
Hash common.Hash `json:"hash"` // Block hash corresponding to this trace
Traces []*txTraceResult `json:"traces"` // Trace results produced by the task
}
// txTraceTask represents a single transaction trace task when an entire block
// is being traced.
type txTraceTask struct {
statedb *state.StateDB // Intermediate state prepped for tracing
index int // Transaction offset in the block
}
// TraceChain returns the structured logs created during the execution of EVM
// between two blocks (excluding start) and returns them as a JSON object.
func (api *API) TraceChain(ctx context.Context, start, end rpc.BlockNumber, config *TraceConfig) (*rpc.Subscription, error) { // Fetch the block interval that we want to trace
from, err := api.blockByNumber(ctx, start)
if err != nil {
return nil, err
}
to, err := api.blockByNumber(ctx, end)
if err != nil {
return nil, err
}
if from.Number().Cmp(to.Number()) >= 0 {
return nil, fmt.Errorf("end block (#%d) needs to come after start block (#%d)", end, start)
}
return api.traceChain(ctx, from, to, config)
}
// traceChain configures a new tracer according to the provided configuration, and
// executes all the transactions contained within. The return value will be one item
// per transaction, dependent on the requested tracer.
func (api *API) traceChain(ctx context.Context, start, end *types.Block, config *TraceConfig) (*rpc.Subscription, error) {
// Tracing a chain is a **long** operation, only do with subscriptions
notifier, supported := rpc.NotifierFromContext(ctx)
if !supported {
return &rpc.Subscription{}, rpc.ErrNotificationsUnsupported
}
sub := notifier.CreateSubscription()
// Prepare all the states for tracing. Note this procedure can take very
// long time. Timeout mechanism is necessary.
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
blocks := int(end.NumberU64() - start.NumberU64())
threads := runtime.NumCPU()
if threads > blocks {
threads = blocks
}
var (
pend = new(sync.WaitGroup)
tasks = make(chan *blockTraceTask, threads)
results = make(chan *blockTraceTask, threads)
localctx = context.Background()
)
for th := 0; th < threads; th++ {
pend.Add(1)
go func() {
defer pend.Done()
// Fetch and execute the next block trace tasks
for task := range tasks {
signer := types.MakeSigner(api.backend.ChainConfig(), task.block.Number())
blockCtx := core.NewEVMBlockContext(task.block.Header(), api.chainContext(localctx), nil)
// Trace all the transactions contained within
for i, tx := range task.block.Transactions() {
msg, _ := tx.AsMessage(signer, task.block.BaseFee())
txctx := &Context{
BlockHash: task.block.Hash(),
TxIndex: i,
TxHash: tx.Hash(),
}
res, err := api.traceTx(localctx, msg, txctx, blockCtx, task.statedb, config)
if err != nil {
task.results[i] = &txTraceResult{Error: err.Error()}
log.Warn("Tracing failed", "hash", tx.Hash(), "block", task.block.NumberU64(), "err", err)
break
}
// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
task.statedb.Finalise(api.backend.ChainConfig().IsEIP158(task.block.Number()))
task.results[i] = &txTraceResult{Result: res}
}
// Stream the result back to the user or abort on teardown
select {
case results <- task:
case <-notifier.Closed():
return
}
}
}()
}
// Start a goroutine to feed all the blocks into the tracers
var (
begin = time.Now()
derefTodo []common.Hash // list of hashes to dereference from the db
derefsMu sync.Mutex // mutex for the derefs
)
go func() {
var (
logged time.Time
number uint64
traced uint64
failed error
parent common.Hash
statedb *state.StateDB
)
// Ensure everything is properly cleaned up on any exit path
defer func() {
close(tasks)
pend.Wait()
switch {
case failed != nil:
log.Warn("Chain tracing failed", "start", start.NumberU64(), "end", end.NumberU64(), "transactions", traced, "elapsed", time.Since(begin), "err", failed)
case number < end.NumberU64():
log.Warn("Chain tracing aborted", "start", start.NumberU64(), "end", end.NumberU64(), "abort", number, "transactions", traced, "elapsed", time.Since(begin))
default:
log.Info("Chain tracing finished", "start", start.NumberU64(), "end", end.NumberU64(), "transactions", traced, "elapsed", time.Since(begin))
}
close(results)
}()
// Feed all the blocks both into the tracer, as well as fast process concurrently
for number = start.NumberU64(); number < end.NumberU64(); number++ {
// Stop tracing if interruption was requested
select {
case <-notifier.Closed():
return
default:
}
// clean out any derefs
derefsMu.Lock()
for _, h := range derefTodo {
statedb.Database().TrieDB().Dereference(h)
}
derefTodo = derefTodo[:0]
derefsMu.Unlock()
// Print progress logs if long enough time elapsed
if time.Since(logged) > 8*time.Second {
logged = time.Now()
log.Info("Tracing chain segment", "start", start.NumberU64(), "end", end.NumberU64(), "current", number, "transactions", traced, "elapsed", time.Since(begin))
}
// Retrieve the parent state to trace on top
block, err := api.blockByNumber(localctx, rpc.BlockNumber(number))
if err != nil {
failed = err
break
}
// Prepare the statedb for tracing. Don't use the live database for
// tracing to avoid persisting state junks into the database.
statedb, err = api.backend.StateAtBlock(localctx, block, reexec, statedb, false)
if err != nil {
failed = err
break
}
if statedb.Database().TrieDB() != nil {
// Hold the reference for tracer, will be released at the final stage
statedb.Database().TrieDB().Reference(block.Root(), common.Hash{})
// Release the parent state because it's already held by the tracer
if parent != (common.Hash{}) {
statedb.Database().TrieDB().Dereference(parent)
}
}
parent = block.Root()
next, err := api.blockByNumber(localctx, rpc.BlockNumber(number+1))
if err != nil {
failed = err
break
}
// Send the block over to the concurrent tracers (if not in the fast-forward phase)
txs := next.Transactions()
select {
case tasks <- &blockTraceTask{statedb: statedb.Copy(), block: next, rootref: block.Root(), results: make([]*txTraceResult, len(txs))}:
case <-notifier.Closed():
return
}
traced += uint64(len(txs))
}
}()
// Keep reading the trace results and stream the to the user
go func() {
var (
done = make(map[uint64]*blockTraceResult)
next = start.NumberU64() + 1
)
for res := range results {
// Queue up next received result
result := &blockTraceResult{
Block: hexutil.Uint64(res.block.NumberU64()),
Hash: res.block.Hash(),
Traces: res.results,
}
// Schedule any parent tries held in memory by this task for dereferencing
done[uint64(result.Block)] = result
derefsMu.Lock()
derefTodo = append(derefTodo, res.rootref)
derefsMu.Unlock()
// Stream completed traces to the user, aborting on the first error
for result, ok := done[next]; ok; result, ok = done[next] {
if len(result.Traces) > 0 || next == end.NumberU64() {
notifier.Notify(sub.ID, result)
}
delete(done, next)
next++
}
}
}()
return sub, nil
}
// TraceBlockByNumber returns the structured logs created during the execution of
// EVM and returns them as a JSON object.
func (api *API) TraceBlockByNumber(ctx context.Context, number rpc.BlockNumber, config *TraceConfig) ([]*txTraceResult, error) {
block, err := api.blockByNumber(ctx, number)
if err != nil {
return nil, err
}
return api.traceBlock(ctx, block, config)
}
// TraceBlockByHash returns the structured logs created during the execution of
// EVM and returns them as a JSON object.
func (api *API) TraceBlockByHash(ctx context.Context, hash common.Hash, config *TraceConfig) ([]*txTraceResult, error) {
block, err := api.blockByHash(ctx, hash)
if err != nil {
return nil, err
}
return api.traceBlock(ctx, block, config)
}
// TraceBlock returns the structured logs created during the execution of EVM
// and returns them as a JSON object.
func (api *API) TraceBlock(ctx context.Context, blob []byte, config *TraceConfig) ([]*txTraceResult, error) {
block := new(types.Block)
if err := rlp.Decode(bytes.NewReader(blob), block); err != nil {
return nil, fmt.Errorf("could not decode block: %v", err)
}
return api.traceBlock(ctx, block, config)
}
// TraceBlockFromFile returns the structured logs created during the execution of
// EVM and returns them as a JSON object.
func (api *API) TraceBlockFromFile(ctx context.Context, file string, config *TraceConfig) ([]*txTraceResult, error) {
blob, err := ioutil.ReadFile(file)
if err != nil {
return nil, fmt.Errorf("could not read file: %v", err)
}
return api.TraceBlock(ctx, blob, config)
}
// TraceBadBlock returns the structured logs created during the execution of
// EVM against a block pulled from the pool of bad ones and returns them as a JSON
// object.
func (api *API) TraceBadBlock(ctx context.Context, hash common.Hash, config *TraceConfig) ([]*txTraceResult, error) {
block := rawdb.ReadBadBlock(api.backend.ChainDb(), hash)
if block == nil {
return nil, fmt.Errorf("bad block %#x not found", hash)
}
return api.traceBlock(ctx, block, config)
}
// StandardTraceBlockToFile dumps the structured logs created during the
// execution of EVM to the local file system and returns a list of files
// to the caller.
func (api *API) StandardTraceBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) {
block, err := api.blockByHash(ctx, hash)
if err != nil {
return nil, err
}
return api.standardTraceBlockToFile(ctx, block, config)
}
// IntermediateRoots executes a block (bad- or canon- or side-), and returns a list
// of intermediate roots: the stateroot after each transaction.
func (api *API) IntermediateRoots(ctx context.Context, hash common.Hash, config *TraceConfig) ([]common.Hash, error) {
block, _ := api.blockByHash(ctx, hash)
if block == nil {
// Check in the bad blocks
block = rawdb.ReadBadBlock(api.backend.ChainDb(), hash)
}
if block == nil {
return nil, fmt.Errorf("block %#x not found", hash)
}
if block.NumberU64() == 0 {
return nil, errors.New("genesis is not traceable")
}
parent, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(block.NumberU64()-1), block.ParentHash())
if err != nil {
return nil, err
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, err := api.backend.StateAtBlock(ctx, parent, reexec, nil, true)
if err != nil {
return nil, err
}
var (
roots []common.Hash
signer = types.MakeSigner(api.backend.ChainConfig(), block.Number())
chainConfig = api.backend.ChainConfig()
vmctx = core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
deleteEmptyObjects = chainConfig.IsEIP158(block.Number())
)
for i, tx := range block.Transactions() {
var (
msg, _ = tx.AsMessage(signer, block.BaseFee())
txContext = core.NewEVMTxContext(msg)
vmenv = vm.NewEVM(vmctx, txContext, statedb, chainConfig, vm.Config{})
)
statedb.Prepare(tx.Hash(), i)
if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.Gas())); err != nil {
log.Warn("Tracing intermediate roots did not complete", "txindex", i, "txhash", tx.Hash(), "err", err)
// We intentionally don't return the error here: if we do, then the RPC server will not
// return the roots. Most likely, the caller already knows that a certain transaction fails to
// be included, but still want the intermediate roots that led to that point.
// It may happen the tx_N causes an erroneous state, which in turn causes tx_N+M to not be
// executable.
// N.B: This should never happen while tracing canon blocks, only when tracing bad blocks.
return roots, nil
}
// calling IntermediateRoot will internally call Finalize on the state
// so any modifications are written to the trie
roots = append(roots, statedb.IntermediateRoot(deleteEmptyObjects))
}
return roots, nil
}
// StandardTraceBadBlockToFile dumps the structured logs created during the
// execution of EVM against a block pulled from the pool of bad ones to the
// local file system and returns a list of files to the caller.
func (api *API) StandardTraceBadBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) {
block := rawdb.ReadBadBlock(api.backend.ChainDb(), hash)
if block == nil {
return nil, fmt.Errorf("bad block %#x not found", hash)
}
return api.standardTraceBlockToFile(ctx, block, config)
}
// traceBlock configures a new tracer according to the provided configuration, and
// executes all the transactions contained within. The return value will be one item
// per transaction, dependent on the requestd tracer.
func (api *API) traceBlock(ctx context.Context, block *types.Block, config *TraceConfig) ([]*txTraceResult, error) {
if block.NumberU64() == 0 {
return nil, errors.New("genesis is not traceable")
}
parent, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(block.NumberU64()-1), block.ParentHash())
if err != nil {
return nil, err
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, err := api.backend.StateAtBlock(ctx, parent, reexec, nil, true)
if err != nil {
return nil, err
}
// Execute all the transaction contained within the block concurrently
var (
signer = types.MakeSigner(api.backend.ChainConfig(), block.Number())
txs = block.Transactions()
results = make([]*txTraceResult, len(txs))
pend = new(sync.WaitGroup)
jobs = make(chan *txTraceTask, len(txs))
)
threads := runtime.NumCPU()
if threads > len(txs) {
threads = len(txs)
}
blockCtx := core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
blockHash := block.Hash()
for th := 0; th < threads; th++ {
pend.Add(1)
go func() {
defer pend.Done()
// Fetch and execute the next transaction trace tasks
for task := range jobs {
msg, _ := txs[task.index].AsMessage(signer, block.BaseFee())
txctx := &Context{
BlockHash: blockHash,
TxIndex: task.index,
TxHash: txs[task.index].Hash(),
}
res, err := api.traceTx(ctx, msg, txctx, blockCtx, task.statedb, config)
if err != nil {
results[task.index] = &txTraceResult{Error: err.Error()}
continue
}
results[task.index] = &txTraceResult{Result: res}
}
}()
}
// Feed the transactions into the tracers and return
var failed error
for i, tx := range txs {
// Send the trace task over for execution
jobs <- &txTraceTask{statedb: statedb.Copy(), index: i}
// Generate the next state snapshot fast without tracing
msg, _ := tx.AsMessage(signer, block.BaseFee())
statedb.Prepare(tx.Hash(), i)
vmenv := vm.NewEVM(blockCtx, core.NewEVMTxContext(msg), statedb, api.backend.ChainConfig(), vm.Config{})
if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.Gas())); err != nil {
failed = err
break
}
// Finalize the state so any modifications are written to the trie
// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
statedb.Finalise(vmenv.ChainConfig().IsEIP158(block.Number()))
}
close(jobs)
pend.Wait()
// If execution failed in between, abort
if failed != nil {
return nil, failed
}
return results, nil
}
// standardTraceBlockToFile configures a new tracer which uses standard JSON output,
// and traces either a full block or an individual transaction. The return value will
// be one filename per transaction traced.
func (api *API) standardTraceBlockToFile(ctx context.Context, block *types.Block, config *StdTraceConfig) ([]string, error) {
// If we're tracing a single transaction, make sure it's present
if config != nil && config.TxHash != (common.Hash{}) {
if !containsTx(block, config.TxHash) {
return nil, fmt.Errorf("transaction %#x not found in block", config.TxHash)
}
}
if block.NumberU64() == 0 {
return nil, errors.New("genesis is not traceable")
}
parent, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(block.NumberU64()-1), block.ParentHash())
if err != nil {
return nil, err
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, err := api.backend.StateAtBlock(ctx, parent, reexec, nil, true)
if err != nil {
return nil, err
}
// Retrieve the tracing configurations, or use default values
var (
logConfig vm.LogConfig
txHash common.Hash
)
if config != nil {
logConfig = config.LogConfig
txHash = config.TxHash
}
logConfig.Debug = true
// Execute transaction, either tracing all or just the requested one
var (
dumps []string
signer = types.MakeSigner(api.backend.ChainConfig(), block.Number())
chainConfig = api.backend.ChainConfig()
vmctx = core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
canon = true
)
// Check if there are any overrides: the caller may wish to enable a future
// fork when executing this block. Note, such overrides are only applicable to the
// actual specified block, not any preceding blocks that we have to go through
// in order to obtain the state.
// Therefore, it's perfectly valid to specify `"futureForkBlock": 0`, to enable `futureFork`
if config != nil && config.Overrides != nil {
// Copy the config, to not screw up the main config
// Note: the Clique-part is _not_ deep copied
chainConfigCopy := new(params.ChainConfig)
*chainConfigCopy = *chainConfig
chainConfig = chainConfigCopy
if berlin := config.LogConfig.Overrides.BerlinBlock; berlin != nil {
chainConfig.BerlinBlock = berlin
canon = false
}
}
for i, tx := range block.Transactions() {
// Prepare the trasaction for un-traced execution
var (
msg, _ = tx.AsMessage(signer, block.BaseFee())
txContext = core.NewEVMTxContext(msg)
vmConf vm.Config
dump *os.File
writer *bufio.Writer
err error
)
// If the transaction needs tracing, swap out the configs
if tx.Hash() == txHash || txHash == (common.Hash{}) {
// Generate a unique temporary file to dump it into
prefix := fmt.Sprintf("block_%#x-%d-%#x-", block.Hash().Bytes()[:4], i, tx.Hash().Bytes()[:4])
if !canon {
prefix = fmt.Sprintf("%valt-", prefix)
}
dump, err = ioutil.TempFile(os.TempDir(), prefix)
if err != nil {
return nil, err
}
dumps = append(dumps, dump.Name())
// Swap out the noop logger to the standard tracer
writer = bufio.NewWriter(dump)
vmConf = vm.Config{
Debug: true,
Tracer: vm.NewJSONLogger(&logConfig, writer),
EnablePreimageRecording: true,
}
}
// Execute the transaction and flush any traces to disk
vmenv := vm.NewEVM(vmctx, txContext, statedb, chainConfig, vmConf)
statedb.Prepare(tx.Hash(), i)
_, err = core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.Gas()))
if writer != nil {
writer.Flush()
}
if dump != nil {
dump.Close()
log.Info("Wrote standard trace", "file", dump.Name())
}
if err != nil {
return dumps, err
}
// Finalize the state so any modifications are written to the trie
// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
statedb.Finalise(vmenv.ChainConfig().IsEIP158(block.Number()))
// If we've traced the transaction we were looking for, abort
if tx.Hash() == txHash {
break
}
}
return dumps, nil
}
// containsTx reports whether the transaction with a certain hash
// is contained within the specified block.
func containsTx(block *types.Block, hash common.Hash) bool {
for _, tx := range block.Transactions() {
if tx.Hash() == hash {
return true
}
}
return false
}
// TraceTransaction returns the structured logs created during the execution of EVM
// and returns them as a JSON object.
func (api *API) TraceTransaction(ctx context.Context, hash common.Hash, config *TraceConfig) (interface{}, error) {
_, blockHash, blockNumber, index, err := api.backend.GetTransaction(ctx, hash)
if err != nil {
return nil, err
}
// It shouldn't happen in practice.
if blockNumber == 0 {
return nil, errors.New("genesis is not traceable")
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
block, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(blockNumber), blockHash)
if err != nil {
return nil, err
}
msg, vmctx, statedb, err := api.backend.StateAtTransaction(ctx, block, int(index), reexec)
if err != nil {
return nil, err
}
txctx := &Context{
BlockHash: blockHash,
TxIndex: int(index),
TxHash: hash,
}
return api.traceTx(ctx, msg, txctx, vmctx, statedb, config)
}
// TraceCall lets you trace a given eth_call. It collects the structured logs
// created during the execution of EVM if the given transaction was added on
// top of the provided block and returns them as a JSON object.
// You can provide -2 as a block number to trace on top of the pending block.
func (api *API) TraceCall(ctx context.Context, args ethapi.TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, config *TraceCallConfig) (interface{}, error) {
// Try to retrieve the specified block
var (
err error
block *types.Block
)
if hash, ok := blockNrOrHash.Hash(); ok {
block, err = api.blockByHash(ctx, hash)
} else if number, ok := blockNrOrHash.Number(); ok {
block, err = api.blockByNumber(ctx, number)
} else {
return nil, errors.New("invalid arguments; neither block nor hash specified")
}
if err != nil {
return nil, err
}
// try to recompute the state
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, err := api.backend.StateAtBlock(ctx, block, reexec, nil, true)
if err != nil {
return nil, err
}
// Apply the customized state rules if required.
if config != nil {
if err := config.StateOverrides.Apply(statedb); err != nil {
return nil, err
}
}
// Execute the trace
msg, err := args.ToMessage(api.backend.RPCGasCap(), block.BaseFee())
if err != nil {
return nil, err
}
vmctx := core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
var traceConfig *TraceConfig
if config != nil {
traceConfig = &TraceConfig{
LogConfig: config.LogConfig,
Tracer: config.Tracer,
Timeout: config.Timeout,
Reexec: config.Reexec,
}
}
return api.traceTx(ctx, msg, new(Context), vmctx, statedb, traceConfig)
}
// traceTx configures a new tracer according to the provided configuration, and
// executes the given message in the provided environment. The return value will
// be tracer dependent.
func (api *API) traceTx(ctx context.Context, message core.Message, txctx *Context, vmctx vm.BlockContext, statedb *state.StateDB, config *TraceConfig) (interface{}, error) {
// Assemble the structured logger or the JavaScript tracer
var (
tracer vm.Tracer
err error
txContext = core.NewEVMTxContext(message)
)
switch {
case config != nil && config.Tracer != nil:
// Define a meaningful timeout of a single transaction trace
timeout := defaultTraceTimeout
if config.Timeout != nil {
if timeout, err = time.ParseDuration(*config.Timeout); err != nil {
return nil, err
}
}
// Constuct the JavaScript tracer to execute with
if tracer, err = New(*config.Tracer, txctx); err != nil {
return nil, err
}
// Handle timeouts and RPC cancellations
deadlineCtx, cancel := context.WithTimeout(ctx, timeout)
go func() {
<-deadlineCtx.Done()
if deadlineCtx.Err() == context.DeadlineExceeded {
tracer.(*Tracer).Stop(errors.New("execution timeout"))
}
}()
defer cancel()
case config == nil:
tracer = vm.NewStructLogger(nil)
default:
tracer = vm.NewStructLogger(config.LogConfig)
}
// Run the transaction with tracing enabled.
vmenv := vm.NewEVM(vmctx, txContext, statedb, api.backend.ChainConfig(), vm.Config{Debug: true, Tracer: tracer, NoBaseFee: true})
// Call Prepare to clear out the statedb access list
statedb.Prepare(txctx.TxHash, txctx.TxIndex)
result, err := core.ApplyMessage(vmenv, message, new(core.GasPool).AddGas(message.Gas()))
if err != nil {
return nil, fmt.Errorf("tracing failed: %w", err)
}
// Depending on the tracer type, format and return the output.
switch tracer := tracer.(type) {
case *vm.StructLogger:
// If the result contains a revert reason, return it.
returnVal := fmt.Sprintf("%x", result.Return())
if len(result.Revert()) > 0 {
returnVal = fmt.Sprintf("%x", result.Revert())
}
return &ethapi.ExecutionResult{
Gas: result.UsedGas,
Failed: result.Failed(),
ReturnValue: returnVal,
StructLogs: ethapi.FormatLogs(tracer.StructLogs()),
}, nil
case *Tracer:
return tracer.GetResult()
default:
panic(fmt.Sprintf("bad tracer type %T", tracer))
}
}
// APIs return the collection of RPC services the tracer package offers.
func APIs(backend Backend) []rpc.API {
// Append all the local APIs and return
return []rpc.API{
{
Namespace: "debug",
Version: "1.0",
Service: NewAPI(backend),
Public: false,
},
}
}