133 lines
4.3 KiB
Go
133 lines
4.3 KiB
Go
// Copyright 2021 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package native
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import (
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"encoding/json"
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"math/big"
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"strconv"
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"sync/atomic"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/vm"
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"github.com/ethereum/go-ethereum/eth/tracers"
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)
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func init() {
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register("4byteTracer", newFourByteTracer)
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}
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// fourByteTracer searches for 4byte-identifiers, and collects them for post-processing.
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// It collects the methods identifiers along with the size of the supplied data, so
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// a reversed signature can be matched against the size of the data.
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//
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// Example:
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//
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// > debug.traceTransaction( "0x214e597e35da083692f5386141e69f47e973b2c56e7a8073b1ea08fd7571e9de", {tracer: "4byteTracer"})
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// {
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// 0x27dc297e-128: 1,
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// 0x38cc4831-0: 2,
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// 0x524f3889-96: 1,
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// 0xadf59f99-288: 1,
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// 0xc281d19e-0: 1
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// }
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type fourByteTracer struct {
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noopTracer
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ids map[string]int // ids aggregates the 4byte ids found
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interrupt uint32 // Atomic flag to signal execution interruption
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reason error // Textual reason for the interruption
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activePrecompiles []common.Address // Updated on CaptureStart based on given rules
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}
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// newFourByteTracer returns a native go tracer which collects
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// 4 byte-identifiers of a tx, and implements vm.EVMLogger.
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func newFourByteTracer(ctx *tracers.Context, _ json.RawMessage) (tracers.Tracer, error) {
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t := &fourByteTracer{
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ids: make(map[string]int),
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}
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return t, nil
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}
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// isPrecompiled returns whether the addr is a precompile. Logic borrowed from newJsTracer in eth/tracers/js/tracer.go
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func (t *fourByteTracer) isPrecompiled(addr common.Address) bool {
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for _, p := range t.activePrecompiles {
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if p == addr {
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return true
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}
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}
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return false
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}
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// store saves the given identifier and datasize.
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func (t *fourByteTracer) store(id []byte, size int) {
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key := bytesToHex(id) + "-" + strconv.Itoa(size)
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t.ids[key] += 1
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}
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// CaptureStart implements the EVMLogger interface to initialize the tracing operation.
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func (t *fourByteTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
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// Update list of precompiles based on current block
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rules := env.ChainConfig().Rules(env.Context.BlockNumber, env.Context.Random != nil)
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t.activePrecompiles = vm.ActivePrecompiles(rules)
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// Save the outer calldata also
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if len(input) >= 4 {
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t.store(input[0:4], len(input)-4)
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}
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}
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// CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
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func (t *fourByteTracer) CaptureEnter(op vm.OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
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// Skip if tracing was interrupted
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if atomic.LoadUint32(&t.interrupt) > 0 {
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return
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}
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if len(input) < 4 {
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return
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}
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// primarily we want to avoid CREATE/CREATE2/SELFDESTRUCT
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if op != vm.DELEGATECALL && op != vm.STATICCALL &&
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op != vm.CALL && op != vm.CALLCODE {
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return
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}
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// Skip any pre-compile invocations, those are just fancy opcodes
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if t.isPrecompiled(to) {
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return
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}
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t.store(input[0:4], len(input)-4)
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}
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// GetResult returns the json-encoded nested list of call traces, and any
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// error arising from the encoding or forceful termination (via `Stop`).
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func (t *fourByteTracer) GetResult() (json.RawMessage, error) {
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res, err := json.Marshal(t.ids)
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if err != nil {
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return nil, err
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}
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return res, t.reason
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}
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// Stop terminates execution of the tracer at the first opportune moment.
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func (t *fourByteTracer) Stop(err error) {
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t.reason = err
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atomic.StoreUint32(&t.interrupt, 1)
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}
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func bytesToHex(s []byte) string {
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return "0x" + common.Bytes2Hex(s)
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}
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