github.com/MetalBlockchain/subnet-evm@v0.4.9/eth/tracers/native/revertreason.go (about)

     1  // (c) 2022, Ava Labs, Inc.
     2  //
     3  // This file is a derived work, based on the go-ethereum library whose original
     4  // notices appear below.
     5  //
     6  // It is distributed under a license compatible with the licensing terms of the
     7  // original code from which it is derived.
     8  //
     9  // Much love to the original authors for their work.
    10  // **********
    11  // Copyright 2022 The go-ethereum Authors
    12  // This file is part of the go-ethereum library.
    13  //
    14  // The go-ethereum library is free software: you can redistribute it and/or modify
    15  // it under the terms of the GNU Lesser General Public License as published by
    16  // the Free Software Foundation, either version 3 of the License, or
    17  // (at your option) any later version.
    18  //
    19  // The go-ethereum library is distributed in the hope that it will be useful,
    20  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    21  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    22  // GNU Lesser General Public License for more details.
    23  //
    24  // You should have received a copy of the GNU Lesser General Public License
    25  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    26  
    27  package native
    28  
    29  import (
    30  	"bytes"
    31  	"encoding/json"
    32  	"math/big"
    33  	"sync/atomic"
    34  	"time"
    35  
    36  	"github.com/MetalBlockchain/subnet-evm/accounts/abi"
    37  	"github.com/MetalBlockchain/subnet-evm/core/vm"
    38  	"github.com/MetalBlockchain/subnet-evm/eth/tracers"
    39  	"github.com/MetalBlockchain/subnet-evm/vmerrs"
    40  	"github.com/ethereum/go-ethereum/common"
    41  	"github.com/ethereum/go-ethereum/crypto"
    42  )
    43  
    44  func init() {
    45  	register("revertReasonTracer", newRevertReasonTracer)
    46  }
    47  
    48  var revertSelector = crypto.Keccak256([]byte("Error(string)"))[:4]
    49  
    50  // revertReasonTracer is a go implementation of the Tracer interface which
    51  // track the error message or revert reason return by the contract.
    52  type revertReasonTracer struct {
    53  	env          *vm.EVM
    54  	revertReason string // The revert reason return from the tx, if tx success, empty string return
    55  	interrupt    uint32 // Atomic flag to signal execution interruption
    56  	reason       error  // Textual reason for the interruption
    57  }
    58  
    59  // newRevertReasonTracer returns a new revert reason tracer.
    60  func newRevertReasonTracer(_ *tracers.Context, _ json.RawMessage) (tracers.Tracer, error) {
    61  	return &revertReasonTracer{}, nil
    62  }
    63  
    64  // CaptureStart implements the EVMLogger interface to initialize the tracing operation.
    65  func (t *revertReasonTracer) CaptureStart(env *vm.EVM, _ common.Address, _ common.Address, _ bool, _ []byte, _ uint64, _ *big.Int) {
    66  	t.env = env
    67  }
    68  
    69  // CaptureEnd is called after the call finishes to finalize the tracing.
    70  func (t *revertReasonTracer) CaptureEnd(output []byte, _ uint64, _ time.Duration, err error) {
    71  	if err != nil {
    72  		if err == vmerrs.ErrExecutionReverted && len(output) > 4 && bytes.Equal(output[:4], revertSelector) {
    73  			errMsg, _ := abi.UnpackRevert(output)
    74  			t.revertReason = err.Error() + ": " + errMsg
    75  		} else {
    76  			t.revertReason = err.Error()
    77  		}
    78  	}
    79  }
    80  
    81  // CaptureState implements the EVMLogger interface to trace a single step of VM execution.
    82  func (t *revertReasonTracer) CaptureState(_ uint64, _ vm.OpCode, _, _ uint64, _ *vm.ScopeContext, _ []byte, _ int, _ error) {
    83  }
    84  
    85  // CaptureFault implements the EVMLogger interface to trace an execution fault.
    86  func (t *revertReasonTracer) CaptureFault(_ uint64, _ vm.OpCode, _, _ uint64, _ *vm.ScopeContext, _ int, _ error) {
    87  }
    88  
    89  // CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
    90  func (t *revertReasonTracer) CaptureEnter(_ vm.OpCode, _ common.Address, _ common.Address, _ []byte, _ uint64, _ *big.Int) {
    91  	// Skip if tracing was interrupted
    92  	if atomic.LoadUint32(&t.interrupt) > 0 {
    93  		t.env.Cancel()
    94  		return
    95  	}
    96  }
    97  
    98  // CaptureExit is called when EVM exits a scope, even if the scope didn't
    99  // execute any code.
   100  func (t *revertReasonTracer) CaptureExit(_ []byte, _ uint64, _ error) {}
   101  
   102  func (t *revertReasonTracer) CaptureTxStart(_ uint64) {}
   103  
   104  func (t *revertReasonTracer) CaptureTxEnd(_ uint64) {}
   105  
   106  // GetResult returns an error message json object.
   107  func (t *revertReasonTracer) GetResult() (json.RawMessage, error) {
   108  	res, err := json.Marshal(t.revertReason)
   109  	if err != nil {
   110  		return nil, err
   111  	}
   112  	return res, t.reason
   113  }
   114  
   115  // Stop terminates execution of the tracer at the first opportune moment.
   116  func (t *revertReasonTracer) Stop(err error) {
   117  	t.reason = err
   118  	atomic.StoreUint32(&t.interrupt, 1)
   119  }