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wanderer🌟 / js-primea-hypervisor



Tree: ccc86c04a14c0346d7695e768be928faf4c41267

Files: ccc86c04a14c0346d7695e768be928faf4c41267 / EVMinterface.js

20999 bytesRaw
1/**
2 * This is the Ethereum interface that is exposed to the WASM instance which
3 * enables to interact with the Ethereum Environment
4 */
5const fs = require('fs')
6const path = require('path')
7const ethUtil = require('ethereumjs-util')
8const Vertex = require('merkle-trie')
9const U256 = require('./deps/u256.js')
10const Message = require('./message.js')
11
12const U128_SIZE_BYTES = 16
13const ADDRESS_SIZE_BYTES = 20
14const U256_SIZE_BYTES = 32
15
16// The interface exposed to the WebAessembly VM
17module.exports = class Interface {
18  constructor (api, message, state) {
19    this.message = message
20    this.kernel = api.kernel
21    this.state = api.kernel.state
22    this.api = api
23    this._results = {}
24    const shimBin = fs.readFileSync(path.join(__dirname, '/wasm/interface.wasm'))
25    const shimMod = WebAssembly.Module(shimBin)
26    this.shims = WebAssembly.Instance(shimMod, {
27      'interface': {
28        'useGas': this._useGas.bind(this),
29        'getGasLeftHigh': this._getGasLeftHigh.bind(this),
30        'getGasLeftLow': this._getGasLeftLow.bind(this),
31        'call': this._call.bind(this)
32      }
33    })
34  }
35
36  async initialize () {
37    this.block = await this.kernel.send(this.kernel.ROOT, new Message({
38      data: {
39        getValue: 'block'
40      },
41      sync: true
42    }))
43
44    this.blockchain = await this.kernel.send(this.kernel.ROOT, new Message({
45      data: {
46        getValue: 'blockchain'
47      },
48      sync: true
49    }))
50  }
51
52  get results () {
53    return this._results
54  }
55
56  static get name () {
57    return 'ethereum'
58  }
59
60  get exports () {
61    let exportMethods = [
62      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
63      'getAddress',
64      'getBalance',
65      'getTxOrigin',
66      'getCaller',
67      'getCallValue',
68      'getCallDataSize',
69      'callDataCopy',
70      'callDataCopy256',
71      'getCodeSize',
72      'codeCopy',
73      'getExternalCodeSize',
74      'externalCodeCopy',
75      'getTxGasPrice',
76      'getBlockHash',
77      'getBlockCoinbase',
78      'getBlockTimestamp',
79      'getBlockNumber',
80      'getBlockDifficulty',
81      'getBlockGasLimit',
82      'log',
83      'create',
84      'callCode',
85      'callDelegate',
86      'storageStore',
87      'storageLoad',
88      'return',
89      'selfDestruct'
90    ]
91    let ret = {}
92    exportMethods.forEach((method) => {
93      ret[method] = this[method].bind(this)
94    })
95
96    // add shims
97    ret.useGas = this.shims.exports.useGas
98    ret.getGasLeft = this.shims.exports.getGasLeft
99    ret.call = this.shims.exports.call
100    return ret
101  }
102
103  setModule (mod) {
104    this.module = mod
105  }
106
107  /**
108   * Subtracts an amount to the gas counter
109   * @param {integer} amount the amount to subtract to the gas counter
110   */
111  _useGas (high, low) {
112    this.takeGas(from64bit(high, low))
113  }
114
115  /**
116   * Returns the current amount of gas
117   * @return {integer}
118   */
119  _getGasLeftHigh () {
120    return Math.floor(this.message.gas / 4294967296)
121  }
122
123  /**
124   * Returns the current amount of gas
125   * @return {integer}
126   */
127  _getGasLeftLow () {
128    return this.message.gas
129  }
130
131  /**
132   * Gets address of currently executing account and loads it into memory at
133   * the given offset.
134   * @param {integer} offset
135   */
136  getAddress (offset) {
137    this.takeGas(2)
138    const path = this.message.to
139    path.pop()
140    const address = path.pop()
141    this.setMemory(offset, ADDRESS_SIZE_BYTES, new Buffer(address.slice(2), 'hex'))
142  }
143
144  /**
145   * Gets balance of the given account and loads it into memory at the given
146   * offset.
147   * @param {integer} addressOffset the memory offset to laod the address
148   * @param {integer} resultOffset
149   */
150  getBalance (addressOffset, offset, cbIndex) {
151    this.takeGas(20)
152
153    const path = [this.kernel.PARENT, '0x' + new Buffer(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)).toString('hex')]
154    const opPromise = this.kernel.send(this.kernel.PARENT, new Message({
155      to: path,
156      data: {
157        getValue: 'balance'
158      },
159      sync: true
160    }))
161      .catch(() => new U256(0))
162
163    this.api.pushOpsQueue(opPromise, cbIndex, balance => {
164      this.setMemory(offset, U128_SIZE_BYTES, new U256(balance).toMemory(U128_SIZE_BYTES))
165    })
166  }
167
168  /**
169   * Gets the execution's origination address and loads it into memory at the
170   * given offset. This is the sender of original transaction; it is never an
171   * account with non-empty associated code.
172   * @param {integer} offset
173   */
174  getTxOrigin (offset) {
175    this.takeGas(2)
176
177    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.message.origin.toMemory())
178  }
179
180  /**
181   * Gets caller address and loads it into memory at the given offset. This is
182   * the address of the account that is directly responsible for this execution.
183   * @param {integer} offset
184   */
185  getCaller (offset) {
186    this.takeGas(2)
187
188    const caller = this.message.from[1]
189    this.setMemory(offset, ADDRESS_SIZE_BYTES, new Buffer(caller.slice(2), 'hex'))
190  }
191
192  /**
193   * Gets the deposited value by the instruction/transaction responsible for
194   * this execution and loads it into memory at the given location.
195   * @param {integer} offset
196   */
197  getCallValue (offset) {
198    this.takeGas(2)
199
200    this.setMemory(offset, U128_SIZE_BYTES, this.message.value.toMemory(U128_SIZE_BYTES))
201  }
202
203  /**
204   * Get size of input data in current environment. This pertains to the input
205   * data passed with the message call instruction or transaction.
206   * @return {integer}
207   */
208  getCallDataSize () {
209    this.takeGas(2)
210
211    return this.message.data.length
212  }
213
214  /**
215   * Copys the input data in current environment to memory. This pertains to
216   * the input data passed with the message call instruction or transaction.
217   * @param {integer} offset the offset in memory to load into
218   * @param {integer} dataOffset the offset in the input data
219   * @param {integer} length the length of data to copy
220   */
221  callDataCopy (offset, dataOffset, length) {
222    this.takeGas(3 + Math.ceil(length / 32) * 3)
223
224    if (length) {
225      const callData = this.message.data.slice(dataOffset, dataOffset + length)
226      this.setMemory(offset, length, callData)
227    }
228  }
229
230  /**
231   * Copys the input data in current environment to memory. This pertains to
232   * the input data passed with the message call instruction or transaction.
233   * @param {integer} offset the offset in memory to load into
234   * @param {integer} dataOffset the offset in the input data
235   */
236  callDataCopy256 (offset, dataOffset) {
237    this.takeGas(3)
238    const callData = this.message.data.slice(dataOffset, dataOffset + 32)
239    this.setMemory(offset, U256_SIZE_BYTES, callData)
240  }
241
242  /**
243   * Gets the size of code running in current environment.
244   * @return {interger}
245   */
246  getCodeSize (cbIndex) {
247    this.takeGas(2)
248
249    const opPromise = this.state
250      .get('code')
251      .then(vertex => vertex.value.length)
252
253    // wait for all the prevouse async ops to finish before running the callback
254    this.kernel.pushOpsQueue(opPromise, cbIndex, length => length)
255  }
256
257  /**
258   * Copys the code running in current environment to memory.
259   * @param {integer} offset the memory offset
260   * @param {integer} codeOffset the code offset
261   * @param {integer} length the length of code to copy
262   */
263  codeCopy (resultOffset, codeOffset, length, cbIndex) {
264    this.takeGas(3 + Math.ceil(length / 32) * 3)
265
266    let opPromise
267
268    if (length) {
269      opPromise = this.state
270        .get('code')
271        .then(vertex => vertex.value)
272    } else {
273      opPromise = Promise.resolve([])
274    }
275
276    // wait for all the prevouse async ops to finish before running the callback
277    this.kernel.pushOpsQueue(opPromise, cbIndex, code => {
278      if (code.length) {
279        code = code.slice(codeOffset, codeOffset + length)
280        this.setMemory(resultOffset, length, code)
281      }
282    })
283  }
284
285  /**
286   * Get size of an account’s code.
287   * @param {integer} addressOffset the offset in memory to load the address from
288   * @return {integer}
289   */
290  getExternalCodeSize (addressOffset, cbOffset) {
291    this.takeGas(20)
292    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
293    const opPromise = this.state.root
294      .get(address)
295      .then(vertex => vertex.value.length)
296      .catch(() => 0)
297
298    // wait for all the prevouse async ops to finish before running the callback
299    this.kernel.pushOpsQueue(opPromise, cbOffset, length => length)
300  }
301
302  /**
303   * Copys the code of an account to memory.
304   * @param {integer} addressOffset the memory offset of the address
305   * @param {integer} resultOffset the memory offset
306   * @param {integer} codeOffset the code offset
307   * @param {integer} length the length of code to copy
308   */
309  externalCodeCopy (addressOffset, resultOffset, codeOffset, length, cbIndex) {
310    this.takeGas(20 + Math.ceil(length / 32) * 3)
311
312    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
313    let opPromise
314
315    if (length) {
316      opPromise = this.state.root
317        .get(address)
318        .then(vertex => vertex.value)
319        .catch(() => [])
320    } else {
321      opPromise = Promise.resolve([])
322    }
323
324    // wait for all the prevouse async ops to finish before running the callback
325    this.kernel.pushOpsQueue(opPromise, cbIndex, code => {
326      if (code.length) {
327        code = code.slice(codeOffset, codeOffset + length)
328        this.setMemory(resultOffset, length, code)
329      }
330    })
331  }
332
333  /**
334   * Gets price of gas in current environment.
335   * @return {integer}
336   */
337  getTxGasPrice () {
338    this.takeGas(2)
339
340    return this.message.gasPrice
341  }
342
343  /**
344   * Gets the hash of one of the 256 most recent complete blocks.
345   * @param {integer} number which block to load
346   * @param {integer} offset the offset to load the hash into
347   */
348  getBlockHash (number, offset, cbOffset) {
349    this.takeGas(20)
350
351    const diff = this.kernel.environment.block.number - number
352    let opPromise
353
354    if (diff > 256 || diff <= 0) {
355      opPromise = Promise.resolve(new U256(0))
356    } else {
357      opPromise = this.state.get(['blockchain', number]).then(vertex => vertex.hash())
358    }
359
360    // wait for all the prevouse async ops to finish before running the callback
361    this.kernel.pushOpsQueue(opPromise, cbOffset, hash => {
362      this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
363    })
364  }
365
366  /**
367   * Gets the block’s beneficiary address and loads into memory.
368   * @param offset
369   */
370  getBlockCoinbase (offset) {
371    this.takeGas(2)
372
373    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.block.header.coinbase)
374  }
375
376  /**
377   * Get the block’s timestamp.
378   * @return {integer}
379   */
380  getBlockTimestamp () {
381    this.takeGas(2)
382
383    return this.kernel.environment.block.timestamp
384  }
385
386  /**
387   * Get the block’s number.
388   * @return {integer}
389   */
390  getBlockNumber () {
391    this.takeGas(2)
392
393    return this.kernel.environment.block.number
394  }
395
396  /**
397   * Get the block’s difficulty.
398   * @return {integer}
399   */
400  getBlockDifficulty (offset) {
401    this.takeGas(2)
402
403    this.setMemory(offset, U256_SIZE_BYTES, this.kernel.environment.block.difficulty.toMemory())
404  }
405
406  /**
407   * Get the block’s gas limit.
408   * @return {integer}
409   */
410  getBlockGasLimit () {
411    this.takeGas(2)
412
413    return this.kernel.environment.block.gasLimit
414  }
415
416  /**
417   * Creates a new log in the current environment
418   * @param {integer} dataOffset the offset in memory to load the memory
419   * @param {integer} length the data length
420   * @param {integer} number of topics
421   */
422  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
423    if (numberOfTopics < 0 || numberOfTopics > 4) {
424      throw new Error('Invalid numberOfTopics')
425    }
426
427    this.takeGas(375 + length * 8 + numberOfTopics * 375)
428
429    const data = length ? this.getMemory(dataOffset, length).slice(0) : new Uint8Array([])
430    const topics = []
431
432    if (numberOfTopics > 0) {
433      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
434    }
435
436    if (numberOfTopics > 1) {
437      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
438    }
439
440    if (numberOfTopics > 2) {
441      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
442    }
443
444    if (numberOfTopics > 3) {
445      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
446    }
447
448    this.kernel.sendMessage([this.kernel.root, 'logs'], new Message({
449      data: data,
450      topics: topics
451    }))
452  }
453
454  /**
455   * Creates a new contract with a given value.
456   * @param {integer} valueOffset the offset in memory to the value from
457   * @param {integer} dataOffset the offset to load the code for the new contract from
458   * @param {integer} length the data length
459   * @param (integer} resultOffset the offset to write the new contract address to
460   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
461   */
462  create (valueOffset, dataOffset, length, resultOffset, cbIndex) {
463    this.takeGas(32000)
464
465    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
466    // if (length) {
467    //   const code = this.getMemory(dataOffset, length).slice(0)
468    // }
469
470    let opPromise
471
472    if (value.gt(this.kernel.environment.value)) {
473      opPromise = Promise.resolve(new Buffer(20).fill(0))
474    } else {
475      // todo actully run the code
476      opPromise = Promise.resolve(ethUtil.generateAddress(this.kernel.environment.address, this.kernel.environment.nonce))
477    }
478
479    // wait for all the prevouse async ops to finish before running the callback
480    this.kernel.pushOpsQueue(opPromise, cbIndex, address => {
481      this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address)
482    })
483  }
484
485  /**
486   * Sends a message with arbiatary data to a given address path
487   * @param {integer} addressOffset the offset to load the address path from
488   * @param {integer} valueOffset the offset to load the value from
489   * @param {integer} dataOffset the offset to load data from
490   * @param {integer} dataLength the length of data
491   * @param {integer} resultOffset the offset to store the result data at
492   * @param {integer} resultLength
493   * @param {integer} gas
494   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
495   */
496  _call (gasHigh, gasLow, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
497    this.takeGas(40)
498
499    const gas = from64bit(gasHigh, gasLow)
500    // Load the params from mem
501    const address = [this.kernel.PARENT, ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
502    const value = new U256(this.getMemory(valueOffset, U128_SIZE_BYTES))
503
504    // Special case for non-zero value; why does this exist?
505    if (!value.isZero()) {
506      this.takeGas(9000 - 2300 + gas)
507      this.takeGas(-gas)
508    }
509
510    // should be
511    let opPromise = this.kernel.send(new Message({
512      to: address,
513      value: value
514    }))
515    .catch(() => {
516      // why does this exist?
517      this.takeGas(25000)
518    })
519
520    // wait for all the prevouse async ops to finish before running the callback
521    this.api.pushOpsQueue(opPromise, cbIndex, () => {
522      return 1
523    })
524  }
525
526  /**
527   * Message-call into this account with an alternative account’s code.
528   * @param {integer} addressOffset the offset to load the address path from
529   * @param {integer} valueOffset the offset to load the value from
530   * @param {integer} dataOffset the offset to load data from
531   * @param {integer} dataLength the length of data
532   * @param {integer} resultOffset the offset to store the result data at
533   * @param {integer} resultLength
534   * @param {integer} gas
535   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
536   */
537  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
538    this.takeGas(40)
539    // Load the params from mem
540    const path = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
541    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
542
543    // Special case for non-zero value; why does this exist?
544    if (!value.isZero()) {
545      this.takeGas(6700)
546    }
547
548    // TODO: should be message?
549    const opPromise = this.state.root.get(path)
550    .catch(() => {
551      // TODO: handle errors
552      // the value was not found
553      return null
554    })
555
556    this.api.pushOpsQueue(opPromise, cbIndex, oldValue => {
557      return 1
558    })
559  }
560
561  /**
562   * Message-call into this account with an alternative account’s code, but
563   * persisting the current values for sender and value.
564   * @param {integer} gas
565   * @param {integer} addressOffset the offset to load the address path from
566   * @param {integer} valueOffset the offset to load the value from
567   * @param {integer} dataOffset the offset to load data from
568   * @param {integer} dataLength the length of data
569   * @param {integer} resultOffset the offset to store the result data at
570   * @param {integer} resultLength
571   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
572   */
573  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
574    // FIXME: count properly
575    this.takeGas(40)
576
577    const data = this.getMemory(dataOffset, dataLength).slice(0)
578    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
579    const [errorCode, result] = this.environment.callDelegate(gas, address, data)
580    this.setMemory(resultOffset, resultLength, result)
581    return errorCode
582  }
583
584  /**
585   * store a value at a given path in long term storage which are both loaded
586   * from Memory
587   * @param {interger} pathOffest the memory offset to load the the path from
588   * @param {interger} valueOffset the memory offset to load the value from
589   */
590  storageStore (pathOffset, valueOffset, cbIndex) {
591    this.takeGas(5000)
592    const path = [new Buffer(this.getMemory(pathOffset, U256_SIZE_BYTES)).toString('hex')]
593    // copy the value
594    const value = this.getMemory(valueOffset, U256_SIZE_BYTES).slice(0)
595    const valIsZero = value.every((i) => i === 0)
596    const opPromise = this.state.get(path)
597      .then(vertex => vertex.value)
598      .catch(() => null)
599
600    this.api.pushOpsQueue(opPromise, cbIndex, oldValue => {
601      if (valIsZero && oldValue) {
602        // delete a value
603        this.kernel.environment.gasRefund += 15000
604        this.state.del(path)
605      } else {
606        if (!valIsZero && !oldValue) {
607          // creating a new value
608          this.takeGas(15000)
609        }
610        // update
611        this.state.set(path, new Vertex({
612          value: value
613        }))
614      }
615    })
616  }
617
618  /**
619   * reterives a value at a given path in long term storage
620   * @param {interger} pathOffest the memory offset to load the the path from
621   * @param {interger} resultOffset the memory offset to load the value from
622   */
623  storageLoad (pathOffset, resultOffset, cbIndex) {
624    this.takeGas(50)
625
626    // convert the path to an array
627    const path = [new Buffer(this.getMemory(pathOffset, U256_SIZE_BYTES)).toString('hex')]
628    // get the value from the state
629    const opPromise = this.state.get(path)
630      .then(vertex => vertex.value)
631      .catch(() => new Uint8Array(32))
632
633    this.api.pushOpsQueue(opPromise, cbIndex, value => {
634      this.setMemory(resultOffset, U256_SIZE_BYTES, value)
635    })
636  }
637
638  /**
639   * Halt execution returning output data.
640   * @param {integer} offset the offset of the output data.
641   * @param {integer} length the length of the output data.
642   */
643  return (offset, length) {
644    if (length) {
645      this.kernel.environment.returnValue = this.getMemory(offset, length).slice(0)
646    }
647  }
648
649  /**
650   * Halt execution and register account for later deletion giving the remaining
651   * balance to an address path
652   * @param {integer} offset the offset to load the address from
653   */
654  selfDestruct (addressOffset) {
655    this.kernel.environment.selfDestruct = true
656    this.kernel.environment.selfDestructAddress = this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)
657    this.kernel.environment.gasRefund += 24000
658  }
659
660  getMemory (offset, length) {
661    return new Uint8Array(this.api.memory(), offset, length)
662  }
663
664  setMemory (offset, length, value) {
665    const memory = new Uint8Array(this.api.memory(), offset, length)
666    memory.set(value)
667  }
668
669  /*
670   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
671   * because every caller of this method is trusted.
672   */
673  takeGas (amount) {
674    if (this.message.gas < amount) {
675      throw new Error('Ran out of gas')
676    }
677    this.message.gas -= amount
678  }
679}
680
681// converts a 64 bit number to a JS number
682function from64bit (high, low) {
683  if (high < 0) {
684    // convert from a 32-bit two's compliment
685    high = 0x100000000 - high
686  }
687  if (low < 0) {
688    // convert from a 32-bit two's compliment
689    low = 0x100000000 - low
690  }
691  // JS only bitshift 32bits, so instead of high << 32 we have high * 2 ^ 32
692  return (high * 4294967296) + low
693}
694

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