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wanderer🌟 / js-primea-hypervisor



Tree: 8ced6c46cc8f744d128a65d00c117a79e68918b8

Files: 8ced6c46cc8f744d128a65d00c117a79e68918b8 / EVMinterface.js

20324 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')
11const common = require('./common.js')
12
13const U128_SIZE_BYTES = 16
14const ADDRESS_SIZE_BYTES = 20
15const U256_SIZE_BYTES = 32
16
17// The interface exposed to the WebAessembly VM
18module.exports = class Interface {
19  constructor (api, message, results) {
20    results.gasRefund = 0
21    this.message = message
22    this.kernel = api.kernel
23    this.api = api
24    this.results = results
25    const shimBin = fs.readFileSync(path.join(__dirname, '/wasm/interface.wasm'))
26    const shimMod = WebAssembly.Module(shimBin)
27    this.shims = WebAssembly.Instance(shimMod, {
28      'interface': {
29        'useGas': this._useGas.bind(this),
30        'getGasLeftHigh': this._getGasLeftHigh.bind(this),
31        'getGasLeftLow': this._getGasLeftLow.bind(this),
32        'call': this._call.bind(this)
33      }
34    })
35  }
36
37  static get name () {
38    return 'ethereum'
39  }
40
41  get exports () {
42    let exportMethods = [
43      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
44      'getAddress',
45      'getBalance',
46      'getTxOrigin',
47      'getCaller',
48      'getCallValue',
49      'getCallDataSize',
50      'callDataCopy',
51      'callDataCopy256',
52      'getCodeSize',
53      'codeCopy',
54      'getExternalCodeSize',
55      'externalCodeCopy',
56      'getTxGasPrice',
57      'getBlockHash',
58      'getBlockCoinbase',
59      'getBlockTimestamp',
60      'getBlockNumber',
61      'getBlockDifficulty',
62      'getBlockGasLimit',
63      'log',
64      'create',
65      'callCode',
66      'callDelegate',
67      'storageStore',
68      'storageLoad',
69      'return',
70      'selfDestruct'
71    ]
72    let ret = {}
73    exportMethods.forEach((method) => {
74      ret[method] = this[method].bind(this)
75    })
76
77    // add shims
78    ret.useGas = this.shims.exports.useGas
79    ret.getGasLeft = this.shims.exports.getGasLeft
80    ret.call = this.shims.exports.call
81    return ret
82  }
83
84  setModule (mod) {
85    this.module = mod
86  }
87
88  /**
89   * Subtracts an amount to the gas counter
90   * @param {integer} amount the amount to subtract to the gas counter
91   */
92  _useGas (high, low) {
93    this.takeGas(from64bit(high, low))
94  }
95
96  /**
97   * Returns the current amount of gas
98   * @return {integer}
99   */
100  _getGasLeftHigh () {
101    return Math.floor(this.message.gas / 4294967296)
102  }
103
104  /**
105   * Returns the current amount of gas
106   * @return {integer}
107   */
108  _getGasLeftLow () {
109    return this.message.gas
110  }
111
112  /**
113   * Gets address of currently executing account and loads it into memory at
114   * the given offset.
115   * @param {integer} offset
116   */
117  getAddress (offset) {
118    this.takeGas(2)
119    const path = this.kernel.path
120    this.setMemory(offset, ADDRESS_SIZE_BYTES, new Buffer(path[1].slice(2), 'hex'))
121  }
122
123  /**
124   * Gets balance of the given account and loads it into memory at the given
125   * offset.
126   * @param {integer} addressOffset the memory offset to laod the address
127   * @param {integer} resultOffset
128   */
129  getBalance (addressOffset, offset, cbIndex) {
130    this.takeGas(20)
131
132    const path = [common.PARENT, '0x' + new Buffer(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)).toString('hex')]
133    const opPromise = this.kernel.send(common.PARENT, new Message({
134      to: path,
135      data: {
136        getValue: 'balance'
137      },
138      sync: true
139    }))
140      .catch(() => new U256(0))
141
142    this.api.pushOpsQueue(opPromise, cbIndex, balance => {
143      this.setMemory(offset, U128_SIZE_BYTES, new U256(balance).toMemory(U128_SIZE_BYTES))
144    })
145  }
146
147  /**
148   * Gets the execution's origination address and loads it into memory at the
149   * given offset. This is the sender of original transaction; it is never an
150   * account with non-empty associated code.
151   * @param {integer} offset
152   */
153  getTxOrigin (offset) {
154    this.takeGas(2)
155
156    const origin = new Buffer(this.message.from[1].slice(2), 'hex')
157    this.setMemory(offset, ADDRESS_SIZE_BYTES, origin)
158  }
159
160  /**
161   * Gets caller address and loads it into memory at the given offset. This is
162   * the address of the account that is directly responsible for this execution.
163   * @param {integer} offset
164   */
165  getCaller (offset) {
166    this.takeGas(2)
167    const caller = this.message.from[2]
168    this.setMemory(offset, ADDRESS_SIZE_BYTES, new Buffer(caller.slice(2), 'hex'))
169  }
170
171  /**
172   * Gets the deposited value by the instruction/transaction responsible for
173   * this execution and loads it into memory at the given location.
174   * @param {integer} offset
175   */
176  getCallValue (offset) {
177    this.takeGas(2)
178
179    this.setMemory(offset, U128_SIZE_BYTES, this.message.value.toMemory(U128_SIZE_BYTES))
180  }
181
182  /**
183   * Get size of input data in current environment. This pertains to the input
184   * data passed with the message call instruction or transaction.
185   * @return {integer}
186   */
187  getCallDataSize () {
188    this.takeGas(2)
189
190    return this.message.data.length
191  }
192
193  /**
194   * Copys the input data in current environment to memory. This pertains to
195   * the input data passed with the message call instruction or transaction.
196   * @param {integer} offset the offset in memory to load into
197   * @param {integer} dataOffset the offset in the input data
198   * @param {integer} length the length of data to copy
199   */
200  callDataCopy (offset, dataOffset, length) {
201    this.takeGas(3 + Math.ceil(length / 32) * 3)
202
203    if (length) {
204      const callData = this.message.data.slice(dataOffset, dataOffset + length)
205      this.setMemory(offset, length, callData)
206    }
207  }
208
209  /**
210   * Copys the input data in current environment to memory. This pertains to
211   * the input data passed with the message call instruction or transaction.
212   * @param {integer} offset the offset in memory to load into
213   * @param {integer} dataOffset the offset in the input data
214   */
215  callDataCopy256 (offset, dataOffset) {
216    this.takeGas(3)
217    const callData = this.message.data.slice(dataOffset, dataOffset + 32)
218    this.setMemory(offset, U256_SIZE_BYTES, callData)
219  }
220
221  /**
222   * Gets the size of code running in current environment.
223   * @return {interger}
224   */
225  getCodeSize (cbIndex) {
226    this.takeGas(2)
227
228    // wait for all the prevouse async ops to finish before running the callback
229    this.api.pushOpsQueue(this.kernel.code.length, cbIndex, length => length)
230  }
231
232  /**
233   * Copys the code running in current environment to memory.
234   * @param {integer} offset the memory offset
235   * @param {integer} codeOffset the code offset
236   * @param {integer} length the length of code to copy
237   */
238  codeCopy (resultOffset, codeOffset, length, cbIndex) {
239    this.takeGas(3 + Math.ceil(length / 32) * 3)
240
241    // wait for all the prevouse async ops to finish before running the callback
242    this.api.pushOpsQueue(this.kernel.code, cbIndex, code => {
243      if (code.length) {
244        code = code.slice(codeOffset, codeOffset + length)
245        this.setMemory(resultOffset, length, code)
246      }
247    })
248  }
249
250  /**
251   * Get size of an account’s code.
252   * @param {integer} addressOffset the offset in memory to load the address from
253   * @return {integer}
254   */
255  getExternalCodeSize (addressOffset, cbOffset) {
256    this.takeGas(20)
257    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
258    const opPromise = this.kernel.sendMessage(common.ROOT, common.getterMessage('code', address))
259      .then(vertex => vertex.value.length)
260      .catch(() => 0)
261
262    // wait for all the prevouse async ops to finish before running the callback
263    this.api.pushOpsQueue(opPromise, cbOffset, length => length)
264  }
265
266  /**
267   * Copys the code of an account to memory.
268   * @param {integer} addressOffset the memory offset of the address
269   * @param {integer} resultOffset the memory offset
270   * @param {integer} codeOffset the code offset
271   * @param {integer} length the length of code to copy
272   */
273  externalCodeCopy (addressOffset, resultOffset, codeOffset, length, cbIndex) {
274    this.takeGas(20 + Math.ceil(length / 32) * 3)
275
276    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
277    let opPromise
278
279    if (length) {
280      opPromise = this.kernel.sendMessage(common.ROOT, common.getterMessage('code', address))
281        .get(address)
282        .then(vertex => vertex.value)
283        .catch(() => [])
284    } else {
285      opPromise = Promise.resolve([])
286    }
287
288    // wait for all the prevouse async ops to finish before running the callback
289    this.api.pushOpsQueue(opPromise, cbIndex, code => {
290      if (code.length) {
291        code = code.slice(codeOffset, codeOffset + length)
292        this.setMemory(resultOffset, length, code)
293      }
294    })
295  }
296
297  /**
298   * Gets price of gas in current environment.
299   * @return {integer}
300   */
301  getTxGasPrice () {
302    this.takeGas(2)
303
304    return this.message.gasPrice
305  }
306
307  /**
308   * Gets the hash of one of the 256 most recent complete blocks.
309   * @param {integer} number which block to load
310   * @param {integer} offset the offset to load the hash into
311   */
312  getBlockHash (number, offset, cbOffset) {
313    this.takeGas(20)
314
315    const diff = this.block.number - number
316    let opPromise
317
318    if (diff > 256 || diff <= 0) {
319      opPromise = Promise.resolve(new U256(0))
320    } else {
321      opPromise = this.state.get(['blockchain', number]).then(vertex => vertex.hash())
322    }
323
324    // wait for all the prevouse async ops to finish before running the callback
325    this.api.pushOpsQueue(opPromise, cbOffset, hash => {
326      this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
327    })
328  }
329
330  /**
331   * Gets the block’s beneficiary address and loads into memory.
332   * @param offset
333   */
334  getBlockCoinbase (offset) {
335    this.takeGas(2)
336
337    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.block.header.coinbase)
338  }
339
340  /**
341   * Get the block’s timestamp.
342   * @return {integer}
343   */
344  getBlockTimestamp () {
345    this.takeGas(2)
346
347    return this.block.timestamp
348  }
349
350  /**
351   * Get the block’s number.
352   * @return {integer}
353   */
354  getBlockNumber () {
355    this.takeGas(2)
356
357    return this.block.number
358  }
359
360  /**
361   * Get the block’s difficulty.
362   * @return {integer}
363   */
364  getBlockDifficulty (offset) {
365    this.takeGas(2)
366
367    this.setMemory(offset, U256_SIZE_BYTES, this.block.difficulty.toMemory())
368  }
369
370  /**
371   * Get the block’s gas limit.
372   * @return {integer}
373   */
374  getBlockGasLimit () {
375    this.takeGas(2)
376
377    return this.message.gasLimit
378  }
379
380  /**
381   * Creates a new log in the current environment
382   * @param {integer} dataOffset the offset in memory to load the memory
383   * @param {integer} length the data length
384   * @param {integer} number of topics
385   */
386  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
387    if (numberOfTopics < 0 || numberOfTopics > 4) {
388      throw new Error('Invalid numberOfTopics')
389    }
390
391    this.takeGas(375 + length * 8 + numberOfTopics * 375)
392
393    const data = length ? this.getMemory(dataOffset, length).slice(0) : new Uint8Array([])
394    const topics = []
395
396    if (numberOfTopics > 0) {
397      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
398    }
399
400    if (numberOfTopics > 1) {
401      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
402    }
403
404    if (numberOfTopics > 2) {
405      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
406    }
407
408    if (numberOfTopics > 3) {
409      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
410    }
411
412    this.kernel.sendMessage([this.kernel.root, 'logs'], new Message({
413      data: data,
414      topics: topics
415    }))
416  }
417
418  /**
419   * Creates a new contract with a given value.
420   * @param {integer} valueOffset the offset in memory to the value from
421   * @param {integer} dataOffset the offset to load the code for the new contract from
422   * @param {integer} length the data length
423   * @param (integer} resultOffset the offset to write the new contract address to
424   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
425   */
426  create (valueOffset, dataOffset, length, resultOffset, cbIndex) {
427    this.takeGas(32000)
428
429    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
430    // if (length) {
431    //   const code = this.getMemory(dataOffset, length).slice(0)
432    // }
433
434    let opPromise
435
436    if (value.gt(this.kernel.environment.value)) {
437      opPromise = Promise.resolve(new Buffer(20).fill(0))
438    } else {
439      // todo actully run the code
440      opPromise = Promise.resolve(ethUtil.generateAddress(this.kernel.environment.address, this.kernel.environment.nonce))
441    }
442
443    // wait for all the prevouse async ops to finish before running the callback
444    this.api.pushOpsQueue(opPromise, cbIndex, address => {
445      this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address)
446    })
447  }
448
449  /**
450   * Sends a message with arbiatary data to a given address path
451   * @param {integer} addressOffset the offset to load the address path from
452   * @param {integer} valueOffset the offset to load the value from
453   * @param {integer} dataOffset the offset to load data from
454   * @param {integer} dataLength the length of data
455   * @param {integer} resultOffset the offset to store the result data at
456   * @param {integer} resultLength
457   * @param {integer} gas
458   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
459   */
460  _call (gasHigh, gasLow, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
461    this.takeGas(40)
462
463    const gas = from64bit(gasHigh, gasLow)
464    // Load the params from mem
465    const address = [common.PARENT, ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
466    const value = new U256(this.getMemory(valueOffset, U128_SIZE_BYTES))
467
468    // Special case for non-zero value; why does this exist?
469    if (!value.isZero()) {
470      this.takeGas(9000 - 2300 + gas)
471      this.takeGas(-gas)
472    }
473
474    // should be
475    let opPromise = this.kernel.send(new Message({
476      to: address,
477      value: value
478    }))
479    .catch(() => {
480      // why does this exist?
481      this.takeGas(25000)
482    })
483
484    // wait for all the prevouse async ops to finish before running the callback
485    this.api.pushOpsQueue(opPromise, cbIndex, () => {
486      return 1
487    })
488  }
489
490  /**
491   * Message-call into this account with an alternative account’s code.
492   * @param {integer} addressOffset the offset to load the address path from
493   * @param {integer} valueOffset the offset to load the value from
494   * @param {integer} dataOffset the offset to load data from
495   * @param {integer} dataLength the length of data
496   * @param {integer} resultOffset the offset to store the result data at
497   * @param {integer} resultLength
498   * @param {integer} gas
499   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
500   */
501  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
502    this.takeGas(40)
503    // Load the params from mem
504    const path = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
505    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
506
507    // Special case for non-zero value; why does this exist?
508    if (!value.isZero()) {
509      this.takeGas(6700)
510    }
511
512    // TODO: should be message?
513    const opPromise = this.state.root.get(path)
514    .catch(() => {
515      // TODO: handle errors
516      // the value was not found
517      return null
518    })
519
520    this.api.pushOpsQueue(opPromise, cbIndex, oldValue => {
521      return 1
522    })
523  }
524
525  /**
526   * Message-call into this account with an alternative account’s code, but
527   * persisting the current values for sender and value.
528   * @param {integer} gas
529   * @param {integer} addressOffset the offset to load the address path from
530   * @param {integer} valueOffset the offset to load the value from
531   * @param {integer} dataOffset the offset to load data from
532   * @param {integer} dataLength the length of data
533   * @param {integer} resultOffset the offset to store the result data at
534   * @param {integer} resultLength
535   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
536   */
537  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
538    // FIXME: count properly
539    this.takeGas(40)
540
541    const data = this.getMemory(dataOffset, dataLength).slice(0)
542    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
543    const [errorCode, result] = this.environment.callDelegate(gas, address, data)
544    this.setMemory(resultOffset, resultLength, result)
545    return errorCode
546  }
547
548  /**
549   * store a value at a given path in long term storage which are both loaded
550   * from Memory
551   * @param {interger} pathOffest the memory offset to load the the path from
552   * @param {interger} valueOffset the memory offset to load the value from
553   */
554  storageStore (pathOffset, valueOffset, cbIndex) {
555    this.takeGas(5000)
556    const path = [new Buffer(this.getMemory(pathOffset, U256_SIZE_BYTES)).toString('hex')]
557    // copy the value
558    const value = this.getMemory(valueOffset, U256_SIZE_BYTES).slice(0)
559    const valIsZero = value.every((i) => i === 0)
560    const opPromise = this.kernel.getValue(path)
561      .then(vertex => vertex.value)
562      .catch(() => null)
563
564    this.api.pushOpsQueue(opPromise, cbIndex, oldValue => {
565      if (valIsZero && oldValue) {
566        // delete a value
567        this.results.gasRefund += 15000
568        this.kernel.deleteValue(path)
569      } else {
570        if (!valIsZero && !oldValue) {
571          // creating a new value
572          this.takeGas(15000)
573        }
574        // update
575        this.kernel.setValue(path, new Vertex({
576          value: value
577        }))
578      }
579    })
580  }
581
582  /**
583   * reterives a value at a given path in long term storage
584   * @param {interger} pathOffest the memory offset to load the the path from
585   * @param {interger} resultOffset the memory offset to load the value from
586   */
587  storageLoad (pathOffset, resultOffset, cbIndex) {
588    this.takeGas(50)
589
590    // convert the path to an array
591    const path = [new Buffer(this.getMemory(pathOffset, U256_SIZE_BYTES)).toString('hex')]
592    // get the value from the state
593    const opPromise = this.kernel.getValue(path)
594      .then(vertex => vertex.value)
595      .catch(() => new Uint8Array(32))
596
597    this.api.pushOpsQueue(opPromise, cbIndex, value => {
598      this.setMemory(resultOffset, U256_SIZE_BYTES, value)
599    })
600  }
601
602  /**
603   * Halt execution returning output data.
604   * @param {integer} offset the offset of the output data.
605   * @param {integer} length the length of the output data.
606   */
607  return (offset, length) {
608    if (length) {
609      this.results.returnValue = this.getMemory(offset, length).slice(0)
610    }
611  }
612
613  /**
614   * Halt execution and register account for later deletion giving the remaining
615   * balance to an address path
616   * @param {integer} offset the offset to load the address from
617   */
618  selfDestruct (addressOffset) {
619    this.results.selfDestruct = true
620    this.results.selfDestructAddress = this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)
621    this.results.gasRefund += 24000
622  }
623
624  getMemory (offset, length) {
625    return new Uint8Array(this.api.memory(), offset, length)
626  }
627
628  setMemory (offset, length, value) {
629    const memory = new Uint8Array(this.api.memory(), offset, length)
630    memory.set(value)
631  }
632
633  /*
634   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
635   * because every caller of this method is trusted.
636   */
637  takeGas (amount) {
638    if (this.message.gas < amount) {
639      throw new Error('Ran out of gas')
640    }
641    this.message.gas -= amount
642  }
643}
644
645// converts a 64 bit number to a JS number
646function from64bit (high, low) {
647  if (high < 0) {
648    // convert from a 32-bit two's compliment
649    high = 0x100000000 - high
650  }
651  if (low < 0) {
652    // convert from a 32-bit two's compliment
653    low = 0x100000000 - low
654  }
655  // JS only bitshift 32bits, so instead of high << 32 we have high * 2 ^ 32
656  return (high * 4294967296) + low
657}
658

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