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wanderer🌟 / js-primea-hypervisor



Tree: f51b785e3c8a0cb4cdd5b659a4410b44e414b871

Files: f51b785e3c8a0cb4cdd5b659a4410b44e414b871 / interface.js

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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 Address = require('./address.js')
6const U256 = require('./u256.js')
7
8const U128_SIZE_BYTES = 16
9const ADDRESS_SIZE_BYTES = 20
10const U256_SIZE_BYTES = 32
11
12// The interface exposed to the WebAessembly Core
13module.exports = class Interface {
14  constructor (environment) {
15    this.environment = environment
16  }
17
18  get exportTable () {
19    let exportMethods = [
20      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
21      'useGas',
22      'getGasLeft',
23      'getAddress',
24      'getBalance',
25      'getTxOrigin',
26      'getCaller',
27      'getCallValue',
28      'getCallDataSize',
29      'callDataCopy',
30      'callDataCopy256',
31      'getCodeSize',
32      'codeCopy',
33      'getExternalCodeSize',
34      'externalCodeCopy',
35      'getTxGasPrice',
36      'getBlockHash',
37      'getBlockCoinbase',
38      'getBlockTimestamp',
39      'getBlockNumber',
40      'getBlockDifficulty',
41      'getBlockGasLimit',
42      'log',
43      'create',
44      'call',
45      'callCode',
46      'callDelegate',
47      'storageStore',
48      'storageLoad',
49      'return',
50      'selfDestruct'
51    ]
52    let ret = {}
53    exportMethods.forEach((method) => {
54      ret[method] = this[method].bind(this)
55    })
56    return ret
57  }
58
59  setModule (mod) {
60    this.module = mod
61  }
62
63  /**
64   * Subtracts an amount to the gas counter
65   * @param {integer} amount the amount to subtract to the gas counter
66   */
67  useGas (amount) {
68    if (amount < 0) {
69      // convert from a 32-bit two's compliment
70      amount = 0x100000000 - amount
71    }
72
73    this.takeGas(amount)
74  }
75
76  /**
77   * Returns the current amount of gas
78   * @return {integer}
79   */
80  getGasLeft () {
81    this.takeGas(2)
82
83    return this.environment.gasLeft
84  }
85
86  /**
87   * Gets address of currently executing account and loads it into memory at
88   * the given offset.
89   * @param {integer} offset
90   */
91  getAddress (offset) {
92    this.takeGas(2)
93
94    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.address.toMemory())
95  }
96
97  /**
98   * Gets balance of the given account and loads it into memory at the given
99   * offset.
100   * @param {integer} addressOffset the memory offset to laod the address
101   * @param {integer} resultOffset
102   */
103  getBalance (addressOffset, offset) {
104    this.takeGas(20)
105
106    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
107    // call the parent contract and ask for the balance of one of its child contracts
108    const balance = this.environment.getBalance(address)
109    this.setMemory(offset, U128_SIZE_BYTES, balance.toMemory(U128_SIZE_BYTES))
110  }
111
112  /**
113   * Gets the execution's origination address and loads it into memory at the
114   * given offset. This is the sender of original transaction; it is never an
115   * account with non-empty associated code.
116   * @param {integer} offset
117   */
118  getTxOrigin (offset) {
119    this.takeGas(2)
120
121    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.origin.toMemory())
122  }
123
124  /**
125   * Gets caller address and loads it into memory at the given offset. This is
126   * the address of the account that is directly responsible for this execution.
127   * @param {integer} offset
128   */
129  getCaller (offset) {
130    this.takeGas(2)
131
132    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.caller.toMemory())
133  }
134
135  /**
136   * Gets the deposited value by the instruction/transaction responsible for
137   * this execution and loads it into memory at the given location.
138   * @param {integer} offset
139   */
140  getCallValue (offset) {
141    this.takeGas(2)
142
143    this.setMemory(offset, U128_SIZE_BYTES, this.environment.callValue.toMemory(U128_SIZE_BYTES))
144  }
145
146  /**
147   * Get size of input data in current environment. This pertains to the input
148   * data passed with the message call instruction or transaction.
149   * @return {integer}
150   */
151  getCallDataSize () {
152    this.takeGas(2)
153
154    return this.environment.callData.length
155  }
156
157  /**
158   * Copys the input data in current environment to memory. This pertains to
159   * the input data passed with the message call instruction or transaction.
160   * @param {integer} offset the offset in memory to load into
161   * @param {integer} dataOffset the offset in the input data
162   * @param {integer} length the length of data to copy
163   */
164  callDataCopy (offset, dataOffset, length) {
165    this.takeGas(3 + Math.ceil(length / 32) * 3)
166
167    if (length) {
168      const callData = this.environment.callData.slice(dataOffset, dataOffset + length)
169      this.setMemory(offset, length, callData)
170    }
171  }
172
173  /**
174   * Copys the input data in current environment to memory. This pertains to
175   * the input data passed with the message call instruction or transaction.
176   * @param {integer} offset the offset in memory to load into
177   * @param {integer} dataOffset the offset in the input data
178   */
179  callDataCopy256 (offset, dataOffset) {
180    this.takeGas(3)
181    const callData = this.environment.callData.slice(dataOffset, dataOffset + 32)
182    this.setMemory(offset, U256_SIZE_BYTES, callData)
183  }
184
185  /**
186   * Gets the size of code running in current environment.
187   * @return {interger}
188   */
189  getCodeSize () {
190    this.takeGas(2)
191
192    return this.environment.code.length
193  }
194
195  /**
196   * Copys the code running in current environment to memory.
197   * @param {integer} offset the memory offset
198   * @param {integer} codeOffset the code offset
199   * @param {integer} length the length of code to copy
200   */
201  codeCopy (resultOffset, codeOffset, length) {
202    this.takeGas(3 + Math.ceil(length / 32) * 3)
203
204    if (length) {
205      const code = this.environment.code.slice(codeOffset, codeOffset + length)
206      this.setMemory(resultOffset, length, code)
207    }
208  }
209
210  /**
211   * Get size of an account’s code.
212   * @param {integer} addressOffset the offset in memory to load the address from
213   * @return {integer}
214   */
215  getExternalCodeSize (addressOffset) {
216    this.takeGas(20)
217
218    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
219    const code = this.environment.getCode(address)
220    return code.length
221  }
222
223  /**
224   * Copys the code of an account to memory.
225   * @param {integer} addressOffset the memory offset of the address
226   * @param {integer} resultOffset the memory offset
227   * @param {integer} codeOffset the code offset
228   * @param {integer} length the length of code to copy
229   */
230  externalCodeCopy (addressOffset, resultOffset, codeOffset, length) {
231    this.takeGas(20 + Math.ceil(length / 32) * 3)
232
233    if (length) {
234      const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
235      let code = this.environment.getCode(address)
236      code = code.slice(codeOffset, codeOffset + length)
237      this.setMemory(resultOffset, length, code)
238    }
239  }
240
241  /**
242   * Gets price of gas in current environment.
243   * @return {integer}
244   */
245  getTxGasPrice () {
246    this.takeGas(2)
247
248    return this.environment.gasPrice
249  }
250
251  /**
252   * Gets the hash of one of the 256 most recent complete blocks.
253   * @param {integer} number which block to load
254   * @param {integer} offset the offset to load the hash into
255   */
256  getBlockHash (number, offset) {
257    this.takeGas(20)
258
259    const diff = this.environment.block.number - number
260    let hash
261
262    if (diff > 256 || diff <= 0) {
263      hash = new U256(0)
264    } else {
265      hash = new U256(this.environment.getBlockHash(number))
266    }
267    this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
268  }
269
270  /**
271   * Gets the block’s beneficiary address and loads into memory.
272   * @param offset
273   */
274  getBlockCoinbase (offset) {
275    this.takeGas(2)
276
277    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.block.coinbase.toMemory())
278  }
279
280  /**
281   * Get the block’s timestamp.
282   * @return {integer}
283   */
284  getBlockTimestamp () {
285    this.takeGas(2)
286
287    return this.environment.block.timestamp
288  }
289
290  /**
291   * Get the block’s number.
292   * @return {integer}
293   */
294  getBlockNumber () {
295    this.takeGas(2)
296
297    return this.environment.block.number
298  }
299
300  /**
301   * Get the block’s difficulty.
302   * @return {integer}
303   */
304  getBlockDifficulty (offset) {
305    this.takeGas(2)
306
307    this.setMemory(offset, U256_SIZE_BYTES, this.environment.block.difficulty.toMemory())
308  }
309
310  /**
311   * Get the block’s gas limit.
312   * @return {integer}
313   */
314  getBlockGasLimit () {
315    this.takeGas(2)
316
317    return this.environment.block.gasLimit
318  }
319
320  /**
321   * Creates a new log in the current environment
322   * @param {integer} dataOffset the offset in memory to load the memory
323   * @param {integer} length the data length
324   * @param {integer} number of topics
325   */
326  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
327    if (numberOfTopics < 0 || numberOfTopics > 4) {
328      throw new Error('Invalid numberOfTopics')
329    }
330
331    this.takeGas(375 + length * 8 + numberOfTopics * 375)
332
333    const data = this.getMemory(dataOffset, length).slice(0)
334    let topics = []
335
336    if (numberOfTopics > 0) {
337      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
338    }
339
340    if (numberOfTopics > 1) {
341      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
342    }
343
344    if (numberOfTopics > 2) {
345      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
346    }
347
348    if (numberOfTopics > 3) {
349      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
350    }
351
352    this.environment.logs.push({
353      data: data,
354      topics: topics
355    })
356  }
357
358  /**
359   * Creates a new contract with a given value.
360   * @param {integer} valueOffset the offset in memory to the value from
361   * @param {integer} dataOffset the offset to load the code for the new contract from
362   * @param {integer} length the data length
363   * @param (integer} resultOffset the offset to write the new contract address to
364   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
365   */
366  create (valueOffset, dataOffset, length, resultOffset) {
367    this.takeGas(32000 + length * 200)
368
369    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
370    const data = this.getMemory(dataOffset, length).slice(0)
371    const [errorCode, address] = this.environment.create(value, data)
372    this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address.toMemory())
373    return errorCode
374  }
375
376  /**
377   * Sends a message with arbiatary data to a given address path
378   * @param {integer} addressOffset the offset to load the address path from
379   * @param {integer} valueOffset the offset to load the value from
380   * @param {integer} dataOffset the offset to load data from
381   * @param {integer} dataLength the length of data
382   * @param {integer} resultOffset the offset to store the result data at
383   * @param {integer} resultLength
384   * @param {integer} gas
385   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
386   */
387  call (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
388    this.takeGas(40 + gas)
389
390    // Load the params from mem
391    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
392    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
393    const data = this.getMemory(dataOffset, dataLength).slice(0)
394
395    // Special case for calling into empty account
396    if (!this.environment.isAccountPresent(address)) {
397      this.takeGas(25000)
398    }
399
400    // Special case for non-zero value
401    if (!value.isZero()) {
402      this.takeGas(9000)
403      gas += 2300
404    }
405
406    const [errorCode, result] = this.environment.call(gas, address, value, data)
407    this.setMemory(resultOffset, resultLength, result)
408    return errorCode
409  }
410
411  /**
412   * Message-call into this account with an alternative account’s code.
413   * @param {integer} addressOffset the offset to load the address path from
414   * @param {integer} valueOffset the offset to load the value from
415   * @param {integer} dataOffset the offset to load data from
416   * @param {integer} dataLength the length of data
417   * @param {integer} resultOffset the offset to store the result data at
418   * @param {integer} resultLength
419   * @param {integer} gas
420   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
421   */
422  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
423    // FIXME: count properly
424    this.takeGas(40)
425
426    // Load the params from mem
427    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
428    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
429    const data = this.getMemory(dataOffset, dataLength).slice(0)
430    const [errorCode, result] = this.environment.callCode(gas, address, value, data)
431    this.setMemory(resultOffset, resultLength, result)
432    return errorCode
433  }
434
435  /**
436   * Message-call into this account with an alternative account’s code, but
437   * persisting the current values for sender and value.
438   * @param {integer} gas
439   * @param {integer} addressOffset the offset to load the address path from
440   * @param {integer} valueOffset the offset to load the value from
441   * @param {integer} dataOffset the offset to load data from
442   * @param {integer} dataLength the length of data
443   * @param {integer} resultOffset the offset to store the result data at
444   * @param {integer} resultLength
445   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
446   */
447  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
448    // FIXME: count properly
449    this.takeGas(40)
450
451    const data = this.getMemory(dataOffset, dataLength).slice(0)
452    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
453    const [errorCode, result] = this.environment.callDelegate(gas, address, data)
454    this.setMemory(resultOffset, resultLength, result)
455    return errorCode
456  }
457
458  /**
459   * store a value at a given path in long term storage which are both loaded
460   * from Memory
461   * @param {interger} pathOffest the memory offset to load the the path from
462   * @param {interger} valueOffset the memory offset to load the value from
463   */
464  storageStore (pathOffset, valueOffset) {
465    const path = new Buffer(this.getMemory(pathOffset, U256_SIZE_BYTES)).toString('hex')
466    // copy the value
467    const value = this.getMemory(valueOffset, U256_SIZE_BYTES).slice(0)
468    const oldValue = this.environment.state.get(path)
469    const valIsZero = value.every((i) => i === 0)
470
471    this.takeGas(5000)
472
473    // write
474    if (!valIsZero && !oldValue) {
475      this.takeGas(15000)
476    }
477
478    // delete
479    if (valIsZero && oldValue) {
480      this.environment.gasRefund += 15000
481      this.environment.state.delete(path)
482    } else {
483      this.environment.state.set(path, value)
484    }
485  }
486
487  /**
488   * reterives a value at a given path in long term storage
489   * @param {interger} pathOffest the memory offset to load the the path from
490   * @param {interger} resultOffset the memory offset to load the value from
491   */
492  storageLoad (pathOffset, resultOffset) {
493    this.takeGas(50)
494
495    const path = new Buffer(this.getMemory(pathOffset, U256_SIZE_BYTES)).toString('hex')
496    const result = this.environment.state.get(path) || new Uint8Array(32)
497    this.setMemory(resultOffset, U256_SIZE_BYTES, result)
498  }
499
500  /**
501   * Halt execution returning output data.
502   * @param {integer} offset the offset of the output data.
503   * @param {integer} length the length of the output data.
504   */
505  return (offset, length) {
506    this.environment.returnValue = this.getMemory(offset, length).slice(0)
507  }
508
509  /**
510   * Halt execution and register account for later deletion giving the remaining
511   * balance to an address path
512   * @param {integer} offset the offset to load the address from
513   */
514  selfDestruct (addressOffset) {
515    this.environment.selfDestruct = true
516    this.environment.selfDestructAddress = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
517    this.environment.gasRefund += 24000
518  }
519
520  getMemory (offset, length) {
521    return new Uint8Array(this.module.exports.memory, offset, length)
522  }
523
524  setMemory (offset, length, value) {
525    const memory = new Uint8Array(this.module.exports.memory, offset, length)
526    memory.set(value)
527  }
528
529  /*
530   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
531   * because every caller of this method is trusted.
532   */
533  takeGas (amount) {
534    if (this.environment.gasLeft < amount) {
535      throw new Error('Ran out of gas')
536    }
537    this.environment.gasLeft -= amount
538  }
539}
540
541//
542// Polyfill required unless this is sorted: https://bugs.chromium.org/p/chromium/issues/detail?id=633895
543//
544// Polyfill from: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_objects/Function/bind
545//
546Function.prototype.bind = function (oThis) { // eslint-disable-line
547  if (typeof this !== 'function') {
548    // closest thing possible to the ECMAScript 5
549    // internal IsCallable function
550    throw new TypeError('Function.prototype.bind - what is trying to be bound is not callable')
551  }
552
553  var aArgs = Array.prototype.slice.call(arguments, 1)
554  var fToBind = this
555  var fNOP = function () {}
556  var fBound = function () {
557    return fToBind.apply(this instanceof fNOP ? this : oThis,
558     aArgs.concat(Array.prototype.slice.call(arguments)))
559  }
560
561  if (this.prototype) {
562    // Function.prototype doesn't have a prototype property
563    fNOP.prototype = this.prototype
564  }
565
566  fBound.prototype = new fNOP() // eslint-disable-line new-cap
567
568  return fBound
569}
570

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