// Copyright 2017 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 eth import ( "bufio" "bytes" "context" "errors" "fmt" "io/ioutil" "os" "runtime" "sync" "time" "github.com/ava-labs/coreth/core" "github.com/ava-labs/coreth/core/rawdb" "github.com/ava-labs/coreth/core/state" "github.com/ava-labs/coreth/core/types" "github.com/ava-labs/coreth/core/vm" "github.com/ava-labs/coreth/eth/tracers" "github.com/ava-labs/coreth/internal/ethapi" "github.com/ava-labs/coreth/rpc" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/common/hexutil" "github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/rlp" "github.com/ethereum/go-ethereum/trie" ) 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) ) // TraceConfig holds extra parameters to trace functions. type TraceConfig struct { *vm.LogConfig Tracer *string Timeout *string Reexec *uint64 } // 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 *PrivateDebugAPI) TraceChain(ctx context.Context, start, end rpc.BlockNumber, config *TraceConfig) (*rpc.Subscription, error) { // Fetch the block interval that we want to trace var from, to *types.Block if start.IsAccepted() { from = api.eth.AcceptedBlock() } else { from = api.eth.blockchain.GetBlockByNumber(uint64(start)) } if end.IsAccepted() { to = api.eth.AcceptedBlock() } else { to = api.eth.blockchain.GetBlockByNumber(uint64(end)) } // Trace the chain if we've found all our blocks if from == nil { return nil, fmt.Errorf("starting block #%d not found", start) } if to == nil { return nil, fmt.Errorf("end block #%d not found", end) } 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 *PrivateDebugAPI) 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() // Ensure we have a valid starting state before doing any work origin := start.NumberU64() database := state.NewDatabaseWithCache(api.eth.ChainDb(), 16, "") // Chain tracing will probably start at genesis if number := start.NumberU64(); number > 0 { start = api.eth.blockchain.GetBlock(start.ParentHash(), start.NumberU64()-1) if start == nil { return nil, fmt.Errorf("parent block #%d not found", number-1) } } statedb, err := state.New(start.Root(), database, nil) if err != nil { // If the starting state is missing, allow some number of blocks to be reexecuted reexec := defaultTraceReexec if config != nil && config.Reexec != nil { reexec = *config.Reexec } // Find the most recent block that has the state available for i := uint64(0); i < reexec; i++ { start = api.eth.blockchain.GetBlock(start.ParentHash(), start.NumberU64()-1) if start == nil { break } if statedb, err = state.New(start.Root(), database, nil); err == nil { break } } // If we still don't have the state available, bail out if err != nil { switch err.(type) { case *trie.MissingNodeError: return nil, errors.New("required historical state unavailable") default: return nil, err } } } // Execute all the transaction contained within the chain concurrently for each block blocks := int(end.NumberU64() - origin) threads := runtime.NumCPU() if threads > blocks { threads = blocks } var ( pend = new(sync.WaitGroup) tasks = make(chan *blockTraceTask, threads) results = make(chan *blockTraceTask, threads) ) 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.eth.blockchain.Config(), task.block.Number()) // Trace all the transactions contained within for i, tx := range task.block.Transactions() { msg, _ := tx.AsMessage(signer) vmctx := core.NewEVMContext(msg, task.block.Header(), api.eth.blockchain, nil) res, err := api.traceTx(ctx, msg, vmctx, 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.eth.blockchain.Config().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 begin := time.Now() go func() { var ( logged time.Time number uint64 traced uint64 failed error proot common.Hash ) // 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() + 1; number <= end.NumberU64(); number++ { // Stop tracing if interruption was requested select { case <-notifier.Closed(): return default: } // Print progress logs if long enough time elapsed if time.Since(logged) > 8*time.Second { if number > origin { nodes, imgs := database.TrieDB().Size() log.Info("Tracing chain segment", "start", origin, "end", end.NumberU64(), "current", number, "transactions", traced, "elapsed", time.Since(begin), "memory", nodes+imgs) } else { log.Info("Preparing state for chain trace", "block", number, "start", origin, "elapsed", time.Since(begin)) } logged = time.Now() } // Retrieve the next block to trace block := api.eth.blockchain.GetBlockByNumber(number) if block == nil { failed = fmt.Errorf("block #%d not found", number) break } // Send the block over to the concurrent tracers (if not in the fast-forward phase) if number > origin { txs := block.Transactions() select { case tasks <- &blockTraceTask{statedb: statedb.Copy(), block: block, rootref: proot, results: make([]*txTraceResult, len(txs))}: case <-notifier.Closed(): return } traced += uint64(len(txs)) } // Generate the next state snapshot fast without tracing _, _, _, err := api.eth.blockchain.Processor().Process(block, statedb, vm.Config{}) if err != nil { failed = err break } // Finalize the state so any modifications are written to the trie root, err := statedb.Commit(api.eth.blockchain.Config().IsEIP158(block.Number())) if err != nil { failed = err break } if err := statedb.Reset(root); err != nil { failed = err break } // Reference the trie twice, once for us, once for the tracer database.TrieDB().Reference(root, common.Hash{}) if number >= origin { database.TrieDB().Reference(root, common.Hash{}) } // Dereference all past tries we ourselves are done working with if proot != (common.Hash{}) { database.TrieDB().Dereference(proot) } proot = root // TODO(karalabe): Do we need the preimages? Won't they accumulate too much? } }() // Keep reading the trace results and stream the to the user go func() { var ( done = make(map[uint64]*blockTraceResult) next = origin + 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, } done[uint64(result.Block)] = result // Dereference any paret tries held in memory by this task database.TrieDB().Dereference(res.rootref) // 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 *PrivateDebugAPI) TraceBlockByNumber(ctx context.Context, number rpc.BlockNumber, config *TraceConfig) ([]*txTraceResult, error) { // Fetch the block that we want to trace var block *types.Block if number.IsAccepted() { block = api.eth.AcceptedBlock() } else { block = api.eth.blockchain.GetBlockByNumber(uint64(number)) } // Trace the block if it was found if block == nil { return nil, fmt.Errorf("block #%d not found", number) } 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 *PrivateDebugAPI) TraceBlockByHash(ctx context.Context, hash common.Hash, config *TraceConfig) ([]*txTraceResult, error) { block := api.eth.blockchain.GetBlockByHash(hash) if block == nil { return nil, fmt.Errorf("block %#x not found", hash) } 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 *PrivateDebugAPI) 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 *PrivateDebugAPI) 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 *PrivateDebugAPI) TraceBadBlock(ctx context.Context, hash common.Hash, config *TraceConfig) ([]*txTraceResult, error) { blocks := api.eth.blockchain.BadBlocks() for _, block := range blocks { if block.Hash() == hash { return api.traceBlock(ctx, block, config) } } return nil, fmt.Errorf("bad block %#x not found", hash) } // 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 *PrivateDebugAPI) StandardTraceBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) { block := api.eth.blockchain.GetBlockByHash(hash) if block == nil { return nil, fmt.Errorf("block %#x not found", hash) } return api.standardTraceBlockToFile(ctx, block, config) } // 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 *PrivateDebugAPI) StandardTraceBadBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) { blocks := api.eth.blockchain.BadBlocks() for _, block := range blocks { if block.Hash() == hash { return api.standardTraceBlockToFile(ctx, block, config) } } return nil, fmt.Errorf("bad block %#x not found", hash) } // 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 *PrivateDebugAPI) traceBlock(ctx context.Context, block *types.Block, config *TraceConfig) ([]*txTraceResult, error) { // Create the parent state database if err := api.eth.engine.VerifyHeader(api.eth.blockchain, block.Header(), true); err != nil { return nil, err } parent := api.eth.blockchain.GetBlock(block.ParentHash(), block.NumberU64()-1) if parent == nil { return nil, fmt.Errorf("parent %#x not found", block.ParentHash()) } reexec := defaultTraceReexec if config != nil && config.Reexec != nil { reexec = *config.Reexec } statedb, err := api.computeStateDB(parent, reexec) if err != nil { return nil, err } // Execute all the transaction contained within the block concurrently var ( signer = types.MakeSigner(api.eth.blockchain.Config(), 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) } 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) vmctx := core.NewEVMContext(msg, block.Header(), api.eth.blockchain, nil) res, err := api.traceTx(ctx, msg, vmctx, 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) vmctx := core.NewEVMContext(msg, block.Header(), api.eth.blockchain, nil) vmenv := vm.NewEVM(vmctx, statedb, api.eth.blockchain.Config(), 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 *PrivateDebugAPI) 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) } } // Create the parent state database if err := api.eth.engine.VerifyHeader(api.eth.blockchain, block.Header(), true); err != nil { return nil, err } parent := api.eth.blockchain.GetBlock(block.ParentHash(), block.NumberU64()-1) if parent == nil { return nil, fmt.Errorf("parent %#x not found", block.ParentHash()) } reexec := defaultTraceReexec if config != nil && config.Reexec != nil { reexec = *config.Reexec } statedb, err := api.computeStateDB(parent, reexec) if err != nil { return nil, err } // Retrieve the tracing configurations, or use default values var ( logConfig vm.LogConfig txHash common.Hash ) if config != nil { if config.LogConfig != nil { logConfig = *config.LogConfig } txHash = config.TxHash } logConfig.Debug = true // Execute transaction, either tracing all or just the requested one var ( signer = types.MakeSigner(api.eth.blockchain.Config(), block.Number()) dumps []string ) for i, tx := range block.Transactions() { // Prepare the trasaction for un-traced execution var ( msg, _ = tx.AsMessage(signer) vmctx = core.NewEVMContext(msg, block.Header(), api.eth.blockchain, nil) 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]) 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, statedb, api.eth.blockchain.Config(), vmConf) _, 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 } // computeStateDB retrieves the state database associated with a certain block. // If no state is locally available for the given block, a number of blocks are // attempted to be reexecuted to generate the desired state. func (api *PrivateDebugAPI) computeStateDB(block *types.Block, reexec uint64) (*state.StateDB, error) { // If we have the state fully available, use that statedb, err := api.eth.blockchain.StateAt(block.Root()) if err == nil { return statedb, nil } // Otherwise try to reexec blocks until we find a state or reach our limit origin := block.NumberU64() database := state.NewDatabaseWithCache(api.eth.ChainDb(), 16, "") for i := uint64(0); i < reexec; i++ { block = api.eth.blockchain.GetBlock(block.ParentHash(), block.NumberU64()-1) if block == nil { break } if statedb, err = state.New(block.Root(), database, nil); err == nil { break } } if err != nil { switch err.(type) { case *trie.MissingNodeError: return nil, fmt.Errorf("required historical state unavailable (reexec=%d)", reexec) default: return nil, err } } // State was available at historical point, regenerate var ( start = time.Now() logged time.Time proot common.Hash ) for block.NumberU64() < origin { // Print progress logs if long enough time elapsed if time.Since(logged) > 8*time.Second { log.Info("Regenerating historical state", "block", block.NumberU64()+1, "target", origin, "remaining", origin-block.NumberU64()-1, "elapsed", time.Since(start)) logged = time.Now() } // Retrieve the next block to regenerate and process it if block = api.eth.blockchain.GetBlockByNumber(block.NumberU64() + 1); block == nil { return nil, fmt.Errorf("block #%d not found", block.NumberU64()+1) } _, _, _, err := api.eth.blockchain.Processor().Process(block, statedb, vm.Config{}) if err != nil { return nil, fmt.Errorf("processing block %d failed: %v", block.NumberU64(), err) } // Finalize the state so any modifications are written to the trie root, err := statedb.Commit(api.eth.blockchain.Config().IsEIP158(block.Number())) if err != nil { return nil, err } if err := statedb.Reset(root); err != nil { return nil, fmt.Errorf("state reset after block %d failed: %v", block.NumberU64(), err) } database.TrieDB().Reference(root, common.Hash{}) if proot != (common.Hash{}) { database.TrieDB().Dereference(proot) } proot = root } nodes, imgs := database.TrieDB().Size() log.Info("Historical state regenerated", "block", block.NumberU64(), "elapsed", time.Since(start), "nodes", nodes, "preimages", imgs) return statedb, nil } // TraceTransaction returns the structured logs created during the execution of EVM // and returns them as a JSON object. func (api *PrivateDebugAPI) TraceTransaction(ctx context.Context, hash common.Hash, config *TraceConfig) (interface{}, error) { // Retrieve the transaction and assemble its EVM context tx, blockHash, _, index := rawdb.ReadTransaction(api.eth.ChainDb(), hash) if tx == nil { return nil, fmt.Errorf("transaction %#x not found", hash) } reexec := defaultTraceReexec if config != nil && config.Reexec != nil { reexec = *config.Reexec } // Retrieve the block block := api.eth.blockchain.GetBlockByHash(blockHash) if block == nil { return nil, fmt.Errorf("block %#x not found", blockHash) } msg, vmctx, statedb, err := api.computeTxEnv(block, int(index), reexec) if err != nil { return nil, err } // Trace the transaction and return return api.traceTx(ctx, msg, 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 *PrivateDebugAPI) TraceCall(ctx context.Context, args ethapi.CallArgs, blockNrOrHash rpc.BlockNumberOrHash, config *TraceConfig) (interface{}, error) { // First try to retrieve the state statedb, header, err := api.eth.APIBackend.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash) if err != nil { // Try to retrieve the specified block var block *types.Block if hash, ok := blockNrOrHash.Hash(); ok { block = api.eth.blockchain.GetBlockByHash(hash) } else if number, ok := blockNrOrHash.Number(); ok { block = api.eth.blockchain.GetBlockByNumber(uint64(number)) } if block == nil { return nil, fmt.Errorf("block %v not found: %v", blockNrOrHash, err) } // try to recompute the state reexec := defaultTraceReexec if config != nil && config.Reexec != nil { reexec = *config.Reexec } _, _, statedb, err = api.computeTxEnv(block, 0, reexec) if err != nil { return nil, err } } // Execute the trace msg := args.ToMessage(api.eth.APIBackend.RPCGasCap()) vmctx := core.NewEVMContext(msg, header, api.eth.blockchain, nil) return api.traceTx(ctx, msg, vmctx, statedb, config) } // 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 *PrivateDebugAPI) traceTx(ctx context.Context, message core.Message, vmctx vm.Context, statedb *state.StateDB, config *TraceConfig) (interface{}, error) { // Assemble the structured logger or the JavaScript tracer var ( tracer vm.Tracer err error ) 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 = tracers.New(*config.Tracer); err != nil { return nil, err } // Handle timeouts and RPC cancellations deadlineCtx, cancel := context.WithTimeout(ctx, timeout) go func() { <-deadlineCtx.Done() tracer.(*tracers.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, statedb, api.eth.blockchain.Config(), vm.Config{Debug: true, Tracer: tracer}) result, err := core.ApplyMessage(vmenv, message, new(core.GasPool).AddGas(message.Gas())) if err != nil { return nil, fmt.Errorf("tracing failed: %v", 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 ðapi.ExecutionResult{ Gas: result.UsedGas, Failed: result.Failed(), ReturnValue: returnVal, StructLogs: ethapi.FormatLogs(tracer.StructLogs()), }, nil case *tracers.Tracer: return tracer.GetResult() default: panic(fmt.Sprintf("bad tracer type %T", tracer)) } } // computeTxEnv returns the execution environment of a certain transaction. func (api *PrivateDebugAPI) computeTxEnv(block *types.Block, txIndex int, reexec uint64) (core.Message, vm.Context, *state.StateDB, error) { // Create the parent state database parent := api.eth.blockchain.GetBlock(block.ParentHash(), block.NumberU64()-1) if parent == nil { return nil, vm.Context{}, nil, fmt.Errorf("parent %#x not found", block.ParentHash()) } statedb, err := api.computeStateDB(parent, reexec) if err != nil { return nil, vm.Context{}, nil, err } if txIndex == 0 && len(block.Transactions()) == 0 { return nil, vm.Context{}, statedb, nil } // Recompute transactions up to the target index. signer := types.MakeSigner(api.eth.blockchain.Config(), block.Number()) for idx, tx := range block.Transactions() { // Assemble the transaction call message and return if the requested offset msg, _ := tx.AsMessage(signer) context := core.NewEVMContext(msg, block.Header(), api.eth.blockchain, nil) if idx == txIndex { return msg, context, statedb, nil } // Not yet the searched for transaction, execute on top of the current state vmenv := vm.NewEVM(context, statedb, api.eth.blockchain.Config(), vm.Config{}) if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(tx.Gas())); err != nil { return nil, vm.Context{}, nil, fmt.Errorf("transaction %#x failed: %v", tx.Hash(), err) } // Ensure any modifications are committed to the state // Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect statedb.Finalise(vmenv.ChainConfig().IsEIP158(block.Number())) } return nil, vm.Context{}, nil, fmt.Errorf("transaction index %d out of range for block %#x", txIndex, block.Hash()) }