aboutsummaryrefslogtreecommitdiffstats
path: root/core/vm/logger.go
blob: 85acb8d6d395b69a9506ea5c4f3e783cec874b8d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
// Copyright 2015 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 vm

import (
    "encoding/hex"
    "fmt"
    "io"
    "math/big"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/common/hexutil"
    "github.com/ethereum/go-ethereum/common/math"
    "github.com/ethereum/go-ethereum/core/types"
)

// Storage represents a contract's storage.
type Storage map[common.Hash]common.Hash

// Copy duplicates the current storage.
func (s Storage) Copy() Storage {
    cpy := make(Storage)
    for key, value := range s {
        cpy[key] = value
    }

    return cpy
}

// LogConfig are the configuration options for structured logger the EVM
type LogConfig struct {
    DisableMemory  bool // disable memory capture
    DisableStack   bool // disable stack capture
    DisableStorage bool // disable storage capture
    Debug          bool // print output during capture end
    Limit          int  // maximum length of output, but zero means unlimited
}

//go:generate gencodec -type StructLog -field-override structLogMarshaling -out gen_structlog.go

// StructLog is emitted to the EVM each cycle and lists information about the current internal state
// prior to the execution of the statement.
type StructLog struct {
    Pc         uint64                      `json:"pc"`
    Op         OpCode                      `json:"op"`
    Gas        uint64                      `json:"gas"`
    GasCost    uint64                      `json:"gasCost"`
    Memory     []byte                      `json:"memory"`
    MemorySize int                         `json:"memSize"`
    Stack      []*big.Int                  `json:"stack"`
    Storage    map[common.Hash]common.Hash `json:"-"`
    Depth      int                         `json:"depth"`
    Err        error                       `json:"-"`
}

// overrides for gencodec
type structLogMarshaling struct {
    Stack       []*math.HexOrDecimal256
    Gas         math.HexOrDecimal64
    GasCost     math.HexOrDecimal64
    Memory      hexutil.Bytes
    OpName      string `json:"opName"` // adds call to OpName() in MarshalJSON
    ErrorString string `json:"error"`  // adds call to ErrorString() in MarshalJSON
}

// OpName formats the operand name in a human-readable format.
func (s *StructLog) OpName() string {
    return s.Op.String()
}

// ErrorString formats the log's error as a string.
func (s *StructLog) ErrorString() string {
    if s.Err != nil {
        return s.Err.Error()
    }
    return ""
}

// Tracer is used to collect execution traces from an EVM transaction
// execution. CaptureState is called for each step of the VM with the
// current VM state.
// Note that reference types are actual VM data structures; make copies
// if you need to retain them beyond the current call.
type Tracer interface {
    CaptureStart(from common.Address, to common.Address, call bool, input []byte, gas uint64, value *big.Int) error
    CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
    CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
    CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error
}

// StructLogger is an EVM state logger and implements Tracer.
//
// StructLogger can capture state based on the given Log configuration and also keeps
// a track record of modified storage which is used in reporting snapshots of the
// contract their storage.
type StructLogger struct {
    cfg LogConfig

    logs          []StructLog
    changedValues map[common.Address]Storage
    output        []byte
    err           error
}

// NewStructLogger returns a new logger
func NewStructLogger(cfg *LogConfig) *StructLogger {
    logger := &StructLogger{
        changedValues: make(map[common.Address]Storage),
    }
    if cfg != nil {
        logger.cfg = *cfg
    }
    return logger
}

// CaptureStart implements the Tracer interface to initialize the tracing operation.
func (l *StructLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
    return nil
}

// CaptureState logs a new structured log message and pushes it out to the environment
//
// CaptureState also tracks SSTORE ops to track dirty values.
func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
    // check if already accumulated the specified number of logs
    if l.cfg.Limit != 0 && l.cfg.Limit <= len(l.logs) {
        return ErrTraceLimitReached
    }

    // initialise new changed values storage container for this contract
    // if not present.
    if l.changedValues[contract.Address()] == nil {
        l.changedValues[contract.Address()] = make(Storage)
    }

    // capture SSTORE opcodes and determine the changed value and store
    // it in the local storage container.
    if op == SSTORE && stack.len() >= 2 {
        var (
            value   = common.BigToHash(stack.data[stack.len()-2])
            address = common.BigToHash(stack.data[stack.len()-1])
        )
        l.changedValues[contract.Address()][address] = value
    }
    // Copy a snapstot of the current memory state to a new buffer
    var mem []byte
    if !l.cfg.DisableMemory {
        mem = make([]byte, len(memory.Data()))
        copy(mem, memory.Data())
    }
    // Copy a snapshot of the current stack state to a new buffer
    var stck []*big.Int
    if !l.cfg.DisableStack {
        stck = make([]*big.Int, len(stack.Data()))
        for i, item := range stack.Data() {
            stck[i] = new(big.Int).Set(item)
        }
    }
    // Copy a snapshot of the current storage to a new container
    var storage Storage
    if !l.cfg.DisableStorage {
        storage = l.changedValues[contract.Address()].Copy()
    }
    // create a new snaptshot of the EVM.
    log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, storage, depth, err}

    l.logs = append(l.logs, log)
    return nil
}

// CaptureFault implements the Tracer interface to trace an execution fault
// while running an opcode.
func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
    return nil
}

// CaptureEnd is called after the call finishes to finalize the tracing.
func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
    l.output = output
    l.err = err
    if l.cfg.Debug {
        fmt.Printf("0x%x\n", output)
        if err != nil {
            fmt.Printf(" error: %v\n", err)
        }
    }
    return nil
}

// StructLogs returns the captured log entries.
func (l *StructLogger) StructLogs() []StructLog { return l.logs }

// Error returns the VM error captured by the trace.
func (l *StructLogger) Error() error { return l.err }

// Output returns the VM return value captured by the trace.
func (l *StructLogger) Output() []byte { return l.output }

// WriteTrace writes a formatted trace to the given writer
func WriteTrace(writer io.Writer, logs []StructLog) {
    for _, log := range logs {
        fmt.Fprintf(writer, "%-16spc=%08d gas=%v cost=%v", log.Op, log.Pc, log.Gas, log.GasCost)
        if log.Err != nil {
            fmt.Fprintf(writer, " ERROR: %v", log.Err)
        }
        fmt.Fprintln(writer)

        if len(log.Stack) > 0 {
            fmt.Fprintln(writer, "Stack:")
            for i := len(log.Stack) - 1; i >= 0; i-- {
                fmt.Fprintf(writer, "%08d  %x\n", len(log.Stack)-i-1, math.PaddedBigBytes(log.Stack[i], 32))
            }
        }
        if len(log.Memory) > 0 {
            fmt.Fprintln(writer, "Memory:")
            fmt.Fprint(writer, hex.Dump(log.Memory))
        }
        if len(log.Storage) > 0 {
            fmt.Fprintln(writer, "Storage:")
            for h, item := range log.Storage {
                fmt.Fprintf(writer, "%x: %x\n", h, item)
            }
        }
        fmt.Fprintln(writer)
    }
}

// WriteLogs writes vm logs in a readable format to the given writer
func WriteLogs(writer io.Writer, logs []*types.Log) {
    for _, log := range logs {
        fmt.Fprintf(writer, "LOG%d: %x bn=%d txi=%x\n", len(log.Topics), log.Address, log.BlockNumber, log.TxIndex)

        for i, topic := range log.Topics {
            fmt.Fprintf(writer, "%08d  %x\n", i, topic)
        }

        fmt.Fprint(writer, hex.Dump(log.Data))
        fmt.Fprintln(writer)
    }
}