forked from btcsuite/btcd
/
scriptval.go
257 lines (228 loc) · 7.14 KB
/
scriptval.go
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// Copyright (c) 2013-2014 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"math"
"runtime"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
)
// txValidateItem holds a transaction along with which input to validate.
type txValidateItem struct {
txInIndex int
txIn *wire.TxIn
tx *btcutil.Tx
}
// txValidator provides a type which asynchronously validates transaction
// inputs. It provides several channels for communication and a processing
// function that is intended to be in run multiple goroutines.
type txValidator struct {
validateChan chan *txValidateItem
quitChan chan struct{}
resultChan chan error
txStore TxStore
flags txscript.ScriptFlags
}
// sendResult sends the result of a script pair validation on the internal
// result channel while respecting the quit channel. The allows orderly
// shutdown when the validation process is aborted early due to a validation
// error in one of the other goroutines.
func (v *txValidator) sendResult(result error) {
select {
case v.resultChan <- result:
case <-v.quitChan:
}
}
// validateHandler consumes items to validate from the internal validate channel
// and returns the result of the validation on the internal result channel. It
// must be run as a goroutine.
func (v *txValidator) validateHandler() {
out:
for {
select {
case txVI := <-v.validateChan:
// Ensure the referenced input transaction is available.
txIn := txVI.txIn
originTxHash := &txIn.PreviousOutPoint.Hash
originTx, exists := v.txStore[*originTxHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input "+
"transaction %v referenced from "+
"transaction %v", originTxHash,
txVI.tx.Sha())
err := ruleError(ErrMissingTx, str)
v.sendResult(err)
break out
}
originMsgTx := originTx.Tx.MsgTx()
// Ensure the output index in the referenced transaction
// is available.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originMsgTx.TxOut)) {
str := fmt.Sprintf("out of bounds "+
"input index %d in transaction %v "+
"referenced from transaction %v",
originTxIndex, originTxHash,
txVI.tx.Sha())
err := ruleError(ErrBadTxInput, str)
v.sendResult(err)
break out
}
// Create a new script engine for the script pair.
sigScript := txIn.SignatureScript
pkScript := originMsgTx.TxOut[originTxIndex].PkScript
vm, err := txscript.NewEngine(pkScript, txVI.tx.MsgTx(),
txVI.txInIndex, v.flags)
if err != nil {
str := fmt.Sprintf("failed to parse input "+
"%s:%d which references output %s:%d - "+
"%v (input script bytes %x, prev output "+
"script bytes %x)", txVI.tx.Sha(),
txVI.txInIndex, originTxHash,
originTxIndex, err, sigScript, pkScript)
err := ruleError(ErrScriptMalformed, str)
v.sendResult(err)
break out
}
// Execute the script pair.
if err := vm.Execute(); err != nil {
str := fmt.Sprintf("failed to validate input "+
"%s:%d which references output %s:%d - "+
"%v (input script bytes %x, prev output "+
"script bytes %x)", txVI.tx.Sha(),
txVI.txInIndex, originTxHash,
originTxIndex, err, sigScript, pkScript)
err := ruleError(ErrScriptValidation, str)
v.sendResult(err)
break out
}
// Validation succeeded.
v.sendResult(nil)
case <-v.quitChan:
break out
}
}
}
// Validate validates the scripts for all of the passed transaction inputs using
// multiple goroutines.
func (v *txValidator) Validate(items []*txValidateItem) error {
if len(items) == 0 {
return nil
}
// Limit the number of goroutines to do script validation based on the
// number of processor cores. This help ensure the system stays
// reasonably responsive under heavy load.
maxGoRoutines := runtime.NumCPU() * 3
if maxGoRoutines <= 0 {
maxGoRoutines = 1
}
if maxGoRoutines > len(items) {
maxGoRoutines = len(items)
}
// Start up validation handlers that are used to asynchronously
// validate each transaction input.
for i := 0; i < maxGoRoutines; i++ {
go v.validateHandler()
}
// Validate each of the inputs. The quit channel is closed when any
// errors occur so all processing goroutines exit regardless of which
// input had the validation error.
numInputs := len(items)
currentItem := 0
processedItems := 0
for processedItems < numInputs {
// Only send items while there are still items that need to
// be processed. The select statement will never select a nil
// channel.
var validateChan chan *txValidateItem
var item *txValidateItem
if currentItem < numInputs {
validateChan = v.validateChan
item = items[currentItem]
}
select {
case validateChan <- item:
currentItem++
case err := <-v.resultChan:
processedItems++
if err != nil {
close(v.quitChan)
return err
}
}
}
close(v.quitChan)
return nil
}
// newTxValidator returns a new instance of txValidator to be used for
// validating transaction scripts asynchronously.
func newTxValidator(txStore TxStore, flags txscript.ScriptFlags) *txValidator {
return &txValidator{
validateChan: make(chan *txValidateItem),
quitChan: make(chan struct{}),
resultChan: make(chan error),
txStore: txStore,
flags: flags,
}
}
// ValidateTransactionScripts validates the scripts for the passed transaction
// using multiple goroutines.
func ValidateTransactionScripts(tx *btcutil.Tx, txStore TxStore, flags txscript.ScriptFlags) error {
// Collect all of the transaction inputs and required information for
// validation.
txIns := tx.MsgTx().TxIn
txValItems := make([]*txValidateItem, 0, len(txIns))
for txInIdx, txIn := range txIns {
// Skip coinbases.
if txIn.PreviousOutPoint.Index == math.MaxUint32 {
continue
}
txVI := &txValidateItem{
txInIndex: txInIdx,
txIn: txIn,
tx: tx,
}
txValItems = append(txValItems, txVI)
}
// Validate all of the inputs.
validator := newTxValidator(txStore, flags)
if err := validator.Validate(txValItems); err != nil {
return err
}
return nil
}
// checkBlockScripts executes and validates the scripts for all transactions in
// the passed block.
func checkBlockScripts(block *btcutil.Block, txStore TxStore,
scriptFlags txscript.ScriptFlags) error {
// Collect all of the transaction inputs and required information for
// validation for all transactions in the block into a single slice.
numInputs := 0
for _, tx := range block.Transactions() {
numInputs += len(tx.MsgTx().TxIn)
}
txValItems := make([]*txValidateItem, 0, numInputs)
for _, tx := range block.Transactions() {
for txInIdx, txIn := range tx.MsgTx().TxIn {
// Skip coinbases.
if txIn.PreviousOutPoint.Index == math.MaxUint32 {
continue
}
txVI := &txValidateItem{
txInIndex: txInIdx,
txIn: txIn,
tx: tx,
}
txValItems = append(txValItems, txVI)
}
}
// Validate all of the inputs.
validator := newTxValidator(txStore, scriptFlags)
if err := validator.Validate(txValItems); err != nil {
return err
}
return nil
}