aboutsummaryrefslogtreecommitdiffstats
path: root/miner/worker.go
blob: 3519e150660e34cef833013773e48d7712373b38 (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
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
// 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 miner

import (
    "fmt"
    "math/big"
    "sort"
    "sync"
    "sync/atomic"
    "time"

    "github.com/ethereum/go-ethereum/accounts"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/core/vm"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/event"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/pow"
    "gopkg.in/fatih/set.v0"
)

var jsonlogger = logger.NewJsonLogger()

const (
    resultQueueSize  = 10
    miningLogAtDepth = 5
)

// Agent can register themself with the worker
type Agent interface {
    Work() chan<- *Work
    SetReturnCh(chan<- *Result)
    Stop()
    Start()
    GetHashRate() int64
}

type uint64RingBuffer struct {
    ints []uint64 //array of all integers in buffer
    next int      //where is the next insertion? assert 0 <= next < len(ints)
}

// environment is the workers current environment and holds
// all of the current state information
type Work struct {
    state              *state.StateDB // apply state changes here
    ancestors          *set.Set       // ancestor set (used for checking uncle parent validity)
    family             *set.Set       // family set (used for checking uncle invalidity)
    uncles             *set.Set       // uncle set
    remove             *set.Set       // tx which will be removed
    tcount             int            // tx count in cycle
    ignoredTransactors *set.Set
    lowGasTransactors  *set.Set
    ownedAccounts      *set.Set
    lowGasTxs          types.Transactions
    localMinedBlocks   *uint64RingBuffer // the most recent block numbers that were mined locally (used to check block inclusion)

    Block *types.Block // the new block

    header   *types.Header
    txs      []*types.Transaction
    receipts []*types.Receipt

    createdAt time.Time
}

type Result struct {
    Work  *Work
    Block *types.Block
}

// worker is the main object which takes care of applying messages to the new state
type worker struct {
    mu sync.Mutex

    agents []Agent
    recv   chan *Result
    mux    *event.TypeMux
    quit   chan struct{}
    pow    pow.PoW

    eth     core.Backend
    chain   *core.BlockChain
    proc    *core.BlockProcessor
    chainDb ethdb.Database

    coinbase common.Address
    gasPrice *big.Int
    extra    []byte

    currentMu sync.Mutex
    current   *Work

    uncleMu        sync.Mutex
    possibleUncles map[common.Hash]*types.Block

    txQueueMu sync.Mutex
    txQueue   map[common.Hash]*types.Transaction

    // atomic status counters
    mining int32
    atWork int32

    fullValidation bool
}

func newWorker(coinbase common.Address, eth core.Backend) *worker {
    worker := &worker{
        eth:            eth,
        mux:            eth.EventMux(),
        chainDb:        eth.ChainDb(),
        recv:           make(chan *Result, resultQueueSize),
        gasPrice:       new(big.Int),
        chain:          eth.BlockChain(),
        proc:           eth.BlockProcessor(),
        possibleUncles: make(map[common.Hash]*types.Block),
        coinbase:       coinbase,
        txQueue:        make(map[common.Hash]*types.Transaction),
        quit:           make(chan struct{}),
        fullValidation: false,
    }
    go worker.update()
    go worker.wait()

    worker.commitNewWork()

    return worker
}

func (self *worker) setEtherbase(addr common.Address) {
    self.mu.Lock()
    defer self.mu.Unlock()
    self.coinbase = addr
}

func (self *worker) pendingState() *state.StateDB {
    self.currentMu.Lock()
    defer self.currentMu.Unlock()
    return self.current.state
}

func (self *worker) pendingBlock() *types.Block {
    self.currentMu.Lock()
    defer self.currentMu.Unlock()

    if atomic.LoadInt32(&self.mining) == 0 {
        return types.NewBlock(
            self.current.header,
            self.current.txs,
            nil,
            self.current.receipts,
        )
    }
    return self.current.Block
}

func (self *worker) start() {
    self.mu.Lock()
    defer self.mu.Unlock()

    atomic.StoreInt32(&self.mining, 1)

    // spin up agents
    for _, agent := range self.agents {
        agent.Start()
    }
}

func (self *worker) stop() {
    self.mu.Lock()
    defer self.mu.Unlock()

    if atomic.LoadInt32(&self.mining) == 1 {
        var keep []Agent
        // stop all agents
        for _, agent := range self.agents {
            agent.Stop()
            // keep all that's not a cpu agent
            if _, ok := agent.(*CpuAgent); !ok {
                keep = append(keep, agent)
            }
        }
        self.agents = keep
    }

    atomic.StoreInt32(&self.mining, 0)
    atomic.StoreInt32(&self.atWork, 0)
}

func (self *worker) register(agent Agent) {
    self.mu.Lock()
    defer self.mu.Unlock()
    self.agents = append(self.agents, agent)
    agent.SetReturnCh(self.recv)
}

func (self *worker) update() {
    eventSub := self.mux.Subscribe(core.ChainHeadEvent{}, core.ChainSideEvent{}, core.TxPreEvent{})
    defer eventSub.Unsubscribe()

    eventCh := eventSub.Chan()
    for {
        select {
        case event, ok := <-eventCh:
            if !ok {
                // Event subscription closed, set the channel to nil to stop spinning
                eventCh = nil
                continue
            }
            // A real event arrived, process interesting content
            switch ev := event.Data.(type) {
            case core.ChainHeadEvent:
                self.commitNewWork()
            case core.ChainSideEvent:
                self.uncleMu.Lock()
                self.possibleUncles[ev.Block.Hash()] = ev.Block
                self.uncleMu.Unlock()
            case core.TxPreEvent:
                // Apply transaction to the pending state if we're not mining
                if atomic.LoadInt32(&self.mining) == 0 {
                    self.currentMu.Lock()
                    self.current.commitTransactions(types.Transactions{ev.Tx}, self.gasPrice, self.proc)
                    self.currentMu.Unlock()
                }
            }
        case <-self.quit:
            return
        }
    }
}

func newLocalMinedBlock(blockNumber uint64, prevMinedBlocks *uint64RingBuffer) (minedBlocks *uint64RingBuffer) {
    if prevMinedBlocks == nil {
        minedBlocks = &uint64RingBuffer{next: 0, ints: make([]uint64, miningLogAtDepth+1)}
    } else {
        minedBlocks = prevMinedBlocks
    }

    minedBlocks.ints[minedBlocks.next] = blockNumber
    minedBlocks.next = (minedBlocks.next + 1) % len(minedBlocks.ints)
    return minedBlocks
}

func (self *worker) wait() {
    for {
        for result := range self.recv {
            atomic.AddInt32(&self.atWork, -1)

            if result == nil {
                continue
            }
            block := result.Block
            work := result.Work

            if self.fullValidation {
                if _, err := self.chain.InsertChain(types.Blocks{block}); err != nil {
                    glog.V(logger.Error).Infoln("mining err", err)
                    continue
                }
                go self.mux.Post(core.NewMinedBlockEvent{block})
            } else {
                work.state.Commit()
                parent := self.chain.GetBlock(block.ParentHash())
                if parent == nil {
                    glog.V(logger.Error).Infoln("Invalid block found during mining")
                    continue
                }
                if err := core.ValidateHeader(self.eth.BlockProcessor().Pow, block.Header(), parent.Header(), true, false); err != nil && err != core.BlockFutureErr {
                    glog.V(logger.Error).Infoln("Invalid header on mined block:", err)
                    continue
                }

                stat, err := self.chain.WriteBlock(block)
                if err != nil {
                    glog.V(logger.Error).Infoln("error writing block to chain", err)
                    continue
                }
                // check if canon block and write transactions
                if stat == core.CanonStatTy {
                    // This puts transactions in a extra db for rpc
                    core.PutTransactions(self.chainDb, block, block.Transactions())
                    // store the receipts
                    core.PutReceipts(self.chainDb, work.receipts)
                    // Write map map bloom filters
                    core.WriteMipmapBloom(self.chainDb, block.NumberU64(), work.receipts)
                }

                // broadcast before waiting for validation
                go func(block *types.Block, logs vm.Logs, receipts []*types.Receipt) {
                    self.mux.Post(core.NewMinedBlockEvent{block})
                    self.mux.Post(core.ChainEvent{block, block.Hash(), logs})
                    if stat == core.CanonStatTy {
                        self.mux.Post(core.ChainHeadEvent{block})
                        self.mux.Post(logs)
                    }
                    if err := core.PutBlockReceipts(self.chainDb, block.Hash(), receipts); err != nil {
                        glog.V(logger.Warn).Infoln("error writing block receipts:", err)
                    }
                }(block, work.state.Logs(), work.receipts)
            }

            // check staleness and display confirmation
            var stale, confirm string
            canonBlock := self.chain.GetBlockByNumber(block.NumberU64())
            if canonBlock != nil && canonBlock.Hash() != block.Hash() {
                stale = "stale "
            } else {
                confirm = "Wait 5 blocks for confirmation"
                work.localMinedBlocks = newLocalMinedBlock(block.Number().Uint64(), work.localMinedBlocks)
            }
            glog.V(logger.Info).Infof("🔨  Mined %sblock (#%v / %x). %s", stale, block.Number(), block.Hash().Bytes()[:4], confirm)

            self.commitNewWork()
        }
    }
}

func (self *worker) push(work *Work) {
    if atomic.LoadInt32(&self.mining) == 1 {
        if core.Canary(work.state) {
            glog.Infoln("Toxicity levels rising to deadly levels. Your canary has died. You can go back or continue down the mineshaft --more--")
            glog.Infoln("You turn back and abort mining")
            return
        }

        // push new work to agents
        for _, agent := range self.agents {
            atomic.AddInt32(&self.atWork, 1)

            if agent.Work() != nil {
                agent.Work() <- work
            }
        }
    }
}

// makeCurrent creates a new environment for the current cycle.
func (self *worker) makeCurrent(parent *types.Block, header *types.Header) error {
    state, err := state.New(parent.Root(), self.eth.ChainDb())
    if err != nil {
        return err
    }
    work := &Work{
        state:     state,
        ancestors: set.New(),
        family:    set.New(),
        uncles:    set.New(),
        header:    header,
        createdAt: time.Now(),
    }

    // when 08 is processed ancestors contain 07 (quick block)
    for _, ancestor := range self.chain.GetBlocksFromHash(parent.Hash(), 7) {
        for _, uncle := range ancestor.Uncles() {
            work.family.Add(uncle.Hash())
        }
        work.family.Add(ancestor.Hash())
        work.ancestors.Add(ancestor.Hash())
    }
    accounts, _ := self.eth.AccountManager().Accounts()

    // Keep track of transactions which return errors so they can be removed
    work.remove = set.New()
    work.tcount = 0
    work.ignoredTransactors = set.New()
    work.lowGasTransactors = set.New()
    work.ownedAccounts = accountAddressesSet(accounts)
    if self.current != nil {
        work.localMinedBlocks = self.current.localMinedBlocks
    }
    self.current = work
    return nil
}

func (w *worker) setGasPrice(p *big.Int) {
    w.mu.Lock()
    defer w.mu.Unlock()

    // calculate the minimal gas price the miner accepts when sorting out transactions.
    const pct = int64(90)
    w.gasPrice = gasprice(p, pct)

    w.mux.Post(core.GasPriceChanged{w.gasPrice})
}

func (self *worker) isBlockLocallyMined(current *Work, deepBlockNum uint64) bool {
    //Did this instance mine a block at {deepBlockNum} ?
    var isLocal = false
    for idx, blockNum := range current.localMinedBlocks.ints {
        if deepBlockNum == blockNum {
            isLocal = true
            current.localMinedBlocks.ints[idx] = 0 //prevent showing duplicate logs
            break
        }
    }
    //Short-circuit on false, because the previous and following tests must both be true
    if !isLocal {
        return false
    }

    //Does the block at {deepBlockNum} send earnings to my coinbase?
    var block = self.chain.GetBlockByNumber(deepBlockNum)
    return block != nil && block.Coinbase() == self.coinbase
}

func (self *worker) logLocalMinedBlocks(current, previous *Work) {
    if previous != nil && current.localMinedBlocks != nil {
        nextBlockNum := current.Block.NumberU64()
        for checkBlockNum := previous.Block.NumberU64(); checkBlockNum < nextBlockNum; checkBlockNum++ {
            inspectBlockNum := checkBlockNum - miningLogAtDepth
            if self.isBlockLocallyMined(current, inspectBlockNum) {
                glog.V(logger.Info).Infof("🔨 🔗  Mined %d blocks back: block #%v", miningLogAtDepth, inspectBlockNum)
            }
        }
    }
}

func (self *worker) commitNewWork() {
    self.mu.Lock()
    defer self.mu.Unlock()
    self.uncleMu.Lock()
    defer self.uncleMu.Unlock()
    self.currentMu.Lock()
    defer self.currentMu.Unlock()

    tstart := time.Now()
    parent := self.chain.CurrentBlock()
    tstamp := tstart.Unix()
    if parent.Time().Cmp(new(big.Int).SetInt64(tstamp)) >= 0 {
        tstamp = parent.Time().Int64() + 1
    }
    // this will ensure we're not going off too far in the future
    if now := time.Now().Unix(); tstamp > now+4 {
        wait := time.Duration(tstamp-now) * time.Second
        glog.V(logger.Info).Infoln("We are too far in the future. Waiting for", wait)
        time.Sleep(wait)
    }

    num := parent.Number()
    header := &types.Header{
        ParentHash: parent.Hash(),
        Number:     num.Add(num, common.Big1),
        Difficulty: core.CalcDifficulty(uint64(tstamp), parent.Time().Uint64(), parent.Number(), parent.Difficulty()),
        GasLimit:   core.CalcGasLimit(parent),
        GasUsed:    new(big.Int),
        Coinbase:   self.coinbase,
        Extra:      self.extra,
        Time:       big.NewInt(tstamp),
    }

    previous := self.current
    // Could potentially happen if starting to mine in an odd state.
    err := self.makeCurrent(parent, header)
    if err != nil {
        glog.V(logger.Info).Infoln("Could not create new env for mining, retrying on next block.")
        return
    }
    work := self.current

    /* //approach 1
    transactions := self.eth.TxPool().GetTransactions()
    sort.Sort(types.TxByNonce{transactions})
    */

    //approach 2
    transactions := self.eth.TxPool().GetTransactions()
    sort.Sort(types.TxByPriceAndNonce{transactions})

    /* // approach 3
    // commit transactions for this run.
    txPerOwner := make(map[common.Address]types.Transactions)
    // Sort transactions by owner
    for _, tx := range self.eth.TxPool().GetTransactions() {
        from, _ := tx.From() // we can ignore the sender error
        txPerOwner[from] = append(txPerOwner[from], tx)
    }
    var (
        singleTxOwner types.Transactions
        multiTxOwner  types.Transactions
    )
    // Categorise transactions by
    // 1. 1 owner tx per block
    // 2. multi txs owner per block
    for _, txs := range txPerOwner {
        if len(txs) == 1 {
            singleTxOwner = append(singleTxOwner, txs[0])
        } else {
            multiTxOwner = append(multiTxOwner, txs...)
        }
    }
    sort.Sort(types.TxByPrice{singleTxOwner})
    sort.Sort(types.TxByNonce{multiTxOwner})
    transactions := append(singleTxOwner, multiTxOwner...)
    */

    work.commitTransactions(transactions, self.gasPrice, self.proc)
    self.eth.TxPool().RemoveTransactions(work.lowGasTxs)

    // compute uncles for the new block.
    var (
        uncles    []*types.Header
        badUncles []common.Hash
    )
    for hash, uncle := range self.possibleUncles {
        if len(uncles) == 2 {
            break
        }
        if err := self.commitUncle(work, uncle.Header()); err != nil {
            if glog.V(logger.Ridiculousness) {
                glog.V(logger.Detail).Infof("Bad uncle found and will be removed (%x)\n", hash[:4])
                glog.V(logger.Detail).Infoln(uncle)
            }
            badUncles = append(badUncles, hash)
        } else {
            glog.V(logger.Debug).Infof("commiting %x as uncle\n", hash[:4])
            uncles = append(uncles, uncle.Header())
        }
    }
    for _, hash := range badUncles {
        delete(self.possibleUncles, hash)
    }

    if atomic.LoadInt32(&self.mining) == 1 {
        // commit state root after all state transitions.
        core.AccumulateRewards(work.state, header, uncles)
        header.Root = work.state.IntermediateRoot()
    }

    // create the new block whose nonce will be mined.
    work.Block = types.NewBlock(header, work.txs, uncles, work.receipts)

    // We only care about logging if we're actually mining.
    if atomic.LoadInt32(&self.mining) == 1 {
        glog.V(logger.Info).Infof("commit new work on block %v with %d txs & %d uncles. Took %v\n", work.Block.Number(), work.tcount, len(uncles), time.Since(tstart))
        self.logLocalMinedBlocks(work, previous)
    }
    self.push(work)
}

func (self *worker) commitUncle(work *Work, uncle *types.Header) error {
    hash := uncle.Hash()
    if work.uncles.Has(hash) {
        return core.UncleError("Uncle not unique")
    }
    if !work.ancestors.Has(uncle.ParentHash) {
        return core.UncleError(fmt.Sprintf("Uncle's parent unknown (%x)", uncle.ParentHash[0:4]))
    }
    if work.family.Has(hash) {
        return core.UncleError(fmt.Sprintf("Uncle already in family (%x)", hash))
    }
    work.uncles.Add(uncle.Hash())
    return nil
}

func (env *Work) commitTransactions(transactions types.Transactions, gasPrice *big.Int, proc *core.BlockProcessor) {
    gp := new(core.GasPool).AddGas(env.header.GasLimit)

    for _, tx := range transactions {
        // We can skip err. It has already been validated in the tx pool
        from, _ := tx.From()

        // Check if it falls within margin. Txs from owned accounts are always processed.
        if tx.GasPrice().Cmp(gasPrice) < 0 && !env.ownedAccounts.Has(from) {
            // ignore the transaction and transactor. We ignore the transactor
            // because nonce will fail after ignoring this transaction so there's
            // no point
            env.lowGasTransactors.Add(from)

            glog.V(logger.Info).Infof("transaction(%x) below gas price (tx=%v ask=%v). All sequential txs from this address(%x) will be ignored\n", tx.Hash().Bytes()[:4], common.CurrencyToString(tx.GasPrice()), common.CurrencyToString(gasPrice), from[:4])
        }

        // Continue with the next transaction if the transaction sender is included in
        // the low gas tx set. This will also remove the tx and all sequential transaction
        // from this transactor
        if env.lowGasTransactors.Has(from) {
            // add tx to the low gas set. This will be removed at the end of the run
            // owned accounts are ignored
            if !env.ownedAccounts.Has(from) {
                env.lowGasTxs = append(env.lowGasTxs, tx)
            }
            continue
        }

        // Move on to the next transaction when the transactor is in ignored transactions set
        // This may occur when a transaction hits the gas limit. When a gas limit is hit and
        // the transaction is processed (that could potentially be included in the block) it
        // will throw a nonce error because the previous transaction hasn't been processed.
        // Therefor we need to ignore any transaction after the ignored one.
        if env.ignoredTransactors.Has(from) {
            continue
        }

        env.state.StartRecord(tx.Hash(), common.Hash{}, 0)

        err := env.commitTransaction(tx, proc, gp)
        switch {
        case core.IsGasLimitErr(err):
            // ignore the transactor so no nonce errors will be thrown for this account
            // next time the worker is run, they'll be picked up again.
            env.ignoredTransactors.Add(from)

            glog.V(logger.Detail).Infof("Gas limit reached for (%x) in this block. Continue to try smaller txs\n", from[:4])
        case err != nil:
            env.remove.Add(tx.Hash())

            if glog.V(logger.Detail) {
                glog.Infof("TX (%x) failed, will be removed: %v\n", tx.Hash().Bytes()[:4], err)
            }
        default:
            env.tcount++
        }
    }
}

func (env *Work) commitTransaction(tx *types.Transaction, proc *core.BlockProcessor, gp *core.GasPool) error {
    snap := env.state.Copy()
    receipt, _, err := proc.ApplyTransaction(gp, env.state, env.header, tx, env.header.GasUsed, true)
    if err != nil {
        env.state.Set(snap)
        return err
    }
    env.txs = append(env.txs, tx)
    env.receipts = append(env.receipts, receipt)
    return nil
}

// TODO: remove or use
func (self *worker) HashRate() int64 {
    return 0
}

// gasprice calculates a reduced gas price based on the pct
// XXX Use big.Rat?
func gasprice(price *big.Int, pct int64) *big.Int {
    p := new(big.Int).Set(price)
    p.Div(p, big.NewInt(100))
    p.Mul(p, big.NewInt(pct))
    return p
}

func accountAddressesSet(accounts []accounts.Account) *set.Set {
    accountSet := set.New()
    for _, account := range accounts {
        accountSet.Add(account.Address)
    }
    return accountSet
}