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wanderer🌟 / js-primea-hypervisor



Tree: e0e6608f9df71b679e52c4d0916732e4e8201fc2

Files: e0e6608f9df71b679e52c4d0916732e4e8201fc2 / EVMinterface.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 fs = require('fs')
6const path = require('path')
7const ethUtil = require('ethereumjs-util')
8const Vertex = require('merkle-trie')
9const U256 = require('./deps/u256.js')
10
11const U128_SIZE_BYTES = 16
12const ADDRESS_SIZE_BYTES = 20
13const U256_SIZE_BYTES = 32
14
15// The interface exposed to the WebAessembly Core
16module.exports = class Interface {
17  constructor (kernel) {
18    this.kernel = kernel
19    const shimBin = fs.readFileSync(path.join(__dirname, '/wasm/interface.wasm'))
20    const shimMod = WebAssembly.Module(shimBin)
21    this.shims = WebAssembly.Instance(shimMod, {
22      'interface': {
23        'useGas': this._useGas.bind(this),
24        'getGasLeftHigh': this._getGasLeftHigh.bind(this),
25        'getGasLeftLow': this._getGasLeftLow.bind(this),
26        'call': this._call.bind(this)
27      }
28    })
29  }
30
31  static get name () {
32    return 'ethereum'
33  }
34
35  get exports () {
36    let exportMethods = [
37      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
38      'getAddress',
39      'getBalance',
40      'getTxOrigin',
41      'getCaller',
42      'getCallValue',
43      'getCallDataSize',
44      'callDataCopy',
45      'callDataCopy256',
46      'getCodeSize',
47      'codeCopy',
48      'getExternalCodeSize',
49      'externalCodeCopy',
50      'getTxGasPrice',
51      'getBlockHash',
52      'getBlockCoinbase',
53      'getBlockTimestamp',
54      'getBlockNumber',
55      'getBlockDifficulty',
56      'getBlockGasLimit',
57      'log',
58      'create',
59      'callCode',
60      'callDelegate',
61      'storageStore',
62      'storageLoad',
63      'return',
64      'selfDestruct'
65    ]
66    let ret = {}
67    exportMethods.forEach((method) => {
68      ret[method] = this[method].bind(this)
69    })
70
71    // add shims
72    ret.useGas = this.shims.exports.useGas
73    ret.getGasLeft = this.shims.exports.getGasLeft
74    ret.call = this.shims.exports.call
75    return ret
76  }
77
78  setModule (mod) {
79    this.module = mod
80  }
81
82  /**
83   * Subtracts an amount to the gas counter
84   * @param {integer} amount the amount to subtract to the gas counter
85   */
86  _useGas (high, low) {
87    this.takeGas(from64bit(high, low))
88  }
89
90  /**
91   * Returns the current amount of gas
92   * @return {integer}
93   */
94  _getGasLeftHigh () {
95    return Math.floor(this.kernel.environment.gasLeft / 4294967296)
96  }
97
98  /**
99   * Returns the current amount of gas
100   * @return {integer}
101   */
102  _getGasLeftLow () {
103    return this.kernel.environment.gasLeft
104  }
105
106  /**
107   * Gets address of currently executing account and loads it into memory at
108   * the given offset.
109   * @param {integer} offset
110   */
111  getAddress (offset) {
112    this.takeGas(2)
113
114    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.address.toMemory())
115  }
116
117  /**
118   * Gets balance of the given account and loads it into memory at the given
119   * offset.
120   * @param {integer} addressOffset the memory offset to laod the address
121   * @param {integer} resultOffset
122   */
123  getBalance (addressOffset, offset, cbIndex) {
124    this.takeGas(20)
125
126    const path = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'balance']
127    const opPromise = this.kernel.environment.state.root.get(path)
128      .then(vertex => new U256(vertex.value))
129      .catch(() => new U256(0))
130
131    this.kernel.pushOpsQueue(opPromise, cbIndex, balance => {
132      this.setMemory(offset, U128_SIZE_BYTES, balance.toMemory(U128_SIZE_BYTES))
133    })
134  }
135
136  /**
137   * Gets the execution's origination address and loads it into memory at the
138   * given offset. This is the sender of original transaction; it is never an
139   * account with non-empty associated code.
140   * @param {integer} offset
141   */
142  getTxOrigin (offset) {
143    this.takeGas(2)
144
145    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.origin.toMemory())
146  }
147
148  /**
149   * Gets caller address and loads it into memory at the given offset. This is
150   * the address of the account that is directly responsible for this execution.
151   * @param {integer} offset
152   */
153  getCaller (offset) {
154    this.takeGas(2)
155
156    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.caller.toMemory())
157  }
158
159  /**
160   * Gets the deposited value by the instruction/transaction responsible for
161   * this execution and loads it into memory at the given location.
162   * @param {integer} offset
163   */
164  getCallValue (offset) {
165    this.takeGas(2)
166
167    this.setMemory(offset, U128_SIZE_BYTES, this.kernel.environment.callValue.toMemory(U128_SIZE_BYTES))
168  }
169
170  /**
171   * Get size of input data in current environment. This pertains to the input
172   * data passed with the message call instruction or transaction.
173   * @return {integer}
174   */
175  getCallDataSize () {
176    this.takeGas(2)
177
178    return this.kernel.environment.callData.length
179  }
180
181  /**
182   * Copys the input data in current environment to memory. This pertains to
183   * the input data passed with the message call instruction or transaction.
184   * @param {integer} offset the offset in memory to load into
185   * @param {integer} dataOffset the offset in the input data
186   * @param {integer} length the length of data to copy
187   */
188  callDataCopy (offset, dataOffset, length) {
189    this.takeGas(3 + Math.ceil(length / 32) * 3)
190
191    if (length) {
192      const callData = this.kernel.environment.callData.slice(dataOffset, dataOffset + length)
193      this.setMemory(offset, length, callData)
194    }
195  }
196
197  /**
198   * Copys the input data in current environment to memory. This pertains to
199   * the input data passed with the message call instruction or transaction.
200   * @param {integer} offset the offset in memory to load into
201   * @param {integer} dataOffset the offset in the input data
202   */
203  callDataCopy256 (offset, dataOffset) {
204    this.takeGas(3)
205    const callData = this.kernel.environment.callData.slice(dataOffset, dataOffset + 32)
206    this.setMemory(offset, U256_SIZE_BYTES, callData)
207  }
208
209  /**
210   * Gets the size of code running in current environment.
211   * @return {interger}
212   */
213  getCodeSize (cbIndex) {
214    this.takeGas(2)
215
216    const opPromise = this.kernel.environment.state
217      .get('code')
218      .then(vertex => vertex.value.length)
219
220    // wait for all the prevouse async ops to finish before running the callback
221    this.kernel.pushOpsQueue(opPromise, cbIndex, length => length)
222  }
223
224  /**
225   * Copys the code running in current environment to memory.
226   * @param {integer} offset the memory offset
227   * @param {integer} codeOffset the code offset
228   * @param {integer} length the length of code to copy
229   */
230  codeCopy (resultOffset, codeOffset, length, cbIndex) {
231    this.takeGas(3 + Math.ceil(length / 32) * 3)
232
233    let opPromise
234
235    if (length) {
236      opPromise = this.kernel.environment.state
237        .get('code')
238        .then(vertex => vertex.value)
239    } else {
240      opPromise = Promise.resolve([])
241    }
242
243    // wait for all the prevouse async ops to finish before running the callback
244    this.kernel.pushOpsQueue(opPromise, cbIndex, code => {
245      if (code.length) {
246        code = code.slice(codeOffset, codeOffset + length)
247        this.setMemory(resultOffset, length, code)
248      }
249    })
250  }
251
252  /**
253   * Get size of an account’s code.
254   * @param {integer} addressOffset the offset in memory to load the address from
255   * @return {integer}
256   */
257  getExternalCodeSize (addressOffset, cbOffset) {
258    this.takeGas(20)
259    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
260    const opPromise = this.kernel.environment.state.root
261      .get(address)
262      .then(vertex => vertex.value.length)
263      .catch(() => 0)
264
265    // wait for all the prevouse async ops to finish before running the callback
266    this.kernel.pushOpsQueue(opPromise, cbOffset, length => length)
267  }
268
269  /**
270   * Copys the code of an account to memory.
271   * @param {integer} addressOffset the memory offset of the address
272   * @param {integer} resultOffset the memory offset
273   * @param {integer} codeOffset the code offset
274   * @param {integer} length the length of code to copy
275   */
276  externalCodeCopy (addressOffset, resultOffset, codeOffset, length, cbIndex) {
277    this.takeGas(20 + Math.ceil(length / 32) * 3)
278
279    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
280    let opPromise
281
282    if (length) {
283      opPromise = this.kernel.environment.state.root
284        .get(address)
285        .then(vertex => vertex.value)
286        .catch(() => [])
287    } else {
288      opPromise = Promise.resolve([])
289    }
290
291    // wait for all the prevouse async ops to finish before running the callback
292    this.kernel.pushOpsQueue(opPromise, cbIndex, code => {
293      if (code.length) {
294        code = code.slice(codeOffset, codeOffset + length)
295        this.setMemory(resultOffset, length, code)
296      }
297    })
298  }
299
300  /**
301   * Gets price of gas in current environment.
302   * @return {integer}
303   */
304  getTxGasPrice () {
305    this.takeGas(2)
306
307    return this.kernel.environment.gasPrice
308  }
309
310  /**
311   * Gets the hash of one of the 256 most recent complete blocks.
312   * @param {integer} number which block to load
313   * @param {integer} offset the offset to load the hash into
314   */
315  getBlockHash (number, offset, cbOffset) {
316    this.takeGas(20)
317
318    const diff = this.kernel.environment.block.number - number
319    let opPromise
320
321    if (diff > 256 || diff <= 0) {
322      opPromise = Promise.resolve(new U256(0))
323    } else {
324      opPromise = this.kernel.environment.getBlockHash(number)
325    }
326
327    // wait for all the prevouse async ops to finish before running the callback
328    this.kernel.pushOpsQueue(opPromise, cbOffset, hash => {
329      this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
330    })
331  }
332
333  /**
334   * Gets the block’s beneficiary address and loads into memory.
335   * @param offset
336   */
337  getBlockCoinbase (offset) {
338    this.takeGas(2)
339
340    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.block.coinbase.toMemory())
341  }
342
343  /**
344   * Get the block’s timestamp.
345   * @return {integer}
346   */
347  getBlockTimestamp () {
348    this.takeGas(2)
349
350    return this.kernel.environment.block.timestamp
351  }
352
353  /**
354   * Get the block’s number.
355   * @return {integer}
356   */
357  getBlockNumber () {
358    this.takeGas(2)
359
360    return this.kernel.environment.block.number
361  }
362
363  /**
364   * Get the block’s difficulty.
365   * @return {integer}
366   */
367  getBlockDifficulty (offset) {
368    this.takeGas(2)
369
370    this.setMemory(offset, U256_SIZE_BYTES, this.kernel.environment.block.difficulty.toMemory())
371  }
372
373  /**
374   * Get the block’s gas limit.
375   * @return {integer}
376   */
377  getBlockGasLimit () {
378    this.takeGas(2)
379
380    return this.kernel.environment.block.gasLimit
381  }
382
383  /**
384   * Creates a new log in the current environment
385   * @param {integer} dataOffset the offset in memory to load the memory
386   * @param {integer} length the data length
387   * @param {integer} number of topics
388   */
389  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
390    if (numberOfTopics < 0 || numberOfTopics > 4) {
391      throw new Error('Invalid numberOfTopics')
392    }
393
394    this.takeGas(375 + length * 8 + numberOfTopics * 375)
395
396    const data = length ? this.getMemory(dataOffset, length).slice(0) : new Uint8Array([])
397    const topics = []
398
399    if (numberOfTopics > 0) {
400      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
401    }
402
403    if (numberOfTopics > 1) {
404      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
405    }
406
407    if (numberOfTopics > 2) {
408      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
409    }
410
411    if (numberOfTopics > 3) {
412      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
413    }
414
415    this.kernel.environment.logs.push({
416      data: data,
417      topics: topics
418    })
419  }
420
421  /**
422   * Creates a new contract with a given value.
423   * @param {integer} valueOffset the offset in memory to the value from
424   * @param {integer} dataOffset the offset to load the code for the new contract from
425   * @param {integer} length the data length
426   * @param (integer} resultOffset the offset to write the new contract address to
427   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
428   */
429  create (valueOffset, dataOffset, length, resultOffset, cbIndex) {
430    this.takeGas(32000)
431
432    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
433    if (length) {
434      const code = this.getMemory(dataOffset, length).slice(0)
435    }
436
437    let opPromise
438
439    if (value.gt(this.kernel.environment.value)) {
440      opPromise = Promise.resolve(new Buffer(20).fill(0))
441    } else {
442      // todo actully run the code
443      opPromise = Promise.resolve(ethUtil.generateAddress(this.kernel.environment.address, this.kernel.environment.nonce))
444    }
445
446    // wait for all the prevouse async ops to finish before running the callback
447    this.kernel.pushOpsQueue(opPromise, cbIndex, address => {
448      this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address)
449    })
450  }
451
452  /**
453   * Sends a message with arbiatary data to a given address path
454   * @param {integer} addressOffset the offset to load the address path from
455   * @param {integer} valueOffset the offset to load the value from
456   * @param {integer} dataOffset the offset to load data from
457   * @param {integer} dataLength the length of data
458   * @param {integer} resultOffset the offset to store the result data at
459   * @param {integer} resultLength
460   * @param {integer} gas
461   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
462   */
463  _call (gasHigh, gasLow, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
464    const gas = from64bit(gasHigh, gasLow)
465    // Load the params from mem
466    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
467    const value = new U256(this.getMemory(valueOffset, U128_SIZE_BYTES))
468
469    this.takeGas(40)
470
471    // Special case for non-zero value; why does this exist?
472    if (!value.isZero()) {
473      this.takeGas(9000 - 2300 + gas)
474      this.takeGas(-gas)
475    }
476
477    let opPromise = this.kernel.environment.state.root.get(address)
478    .catch(() => {
479      // why does this exist?
480      this.takeGas(25000)
481    })
482
483    // wait for all the prevouse async ops to finish before running the callback
484    this.kernel.pushOpsQueue(opPromise, cbIndex, () => {
485      return 1
486    })
487  }
488
489  /**
490   * Message-call into this account with an alternative account’s code.
491   * @param {integer} addressOffset the offset to load the address path from
492   * @param {integer} valueOffset the offset to load the value from
493   * @param {integer} dataOffset the offset to load data from
494   * @param {integer} dataLength the length of data
495   * @param {integer} resultOffset the offset to store the result data at
496   * @param {integer} resultLength
497   * @param {integer} gas
498   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
499   */
500  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
501    this.takeGas(40)
502    // Load the params from mem
503    const path = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
504    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
505
506    // Special case for non-zero value; why does this exist?
507    if (!value.isZero()) {
508      this.takeGas(6700)
509    }
510
511    // TODO: should be message?
512    const opPromise = this.kernel.environment.state.root.get(path)
513    .catch(() => {
514      // TODO: handle errors
515      // the value was not found
516      return null
517    })
518
519    this.kernel.pushOpsQueue(opPromise, cbIndex, oldValue => {
520      return 1
521    })
522  }
523
524  /**
525   * Message-call into this account with an alternative account’s code, but
526   * persisting the current values for sender and value.
527   * @param {integer} gas
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   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
535   */
536  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
537    // FIXME: count properly
538    this.takeGas(40)
539
540    const data = this.getMemory(dataOffset, dataLength).slice(0)
541    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
542    const [errorCode, result] = this.environment.callDelegate(gas, address, data)
543    this.setMemory(resultOffset, resultLength, result)
544    return errorCode
545  }
546
547  /**
548   * store a value at a given path in long term storage which are both loaded
549   * from Memory
550   * @param {interger} pathOffest the memory offset to load the the path from
551   * @param {interger} valueOffset the memory offset to load the value from
552   */
553  storageStore (pathOffset, valueOffset, cbIndex) {
554    this.takeGas(5000)
555    const path = ['storage', ...this.getMemory(pathOffset, U256_SIZE_BYTES)]
556    // copy the value
557    const value = this.getMemory(valueOffset, U256_SIZE_BYTES).slice(0)
558    const valIsZero = value.every((i) => i === 0)
559    const opPromise = this.kernel.environment.state.get(path)
560      .then(vertex => vertex.value)
561      .catch(() => null)
562
563    this.kernel.pushOpsQueue(opPromise, cbIndex, oldValue => {
564      if (valIsZero && oldValue) {
565        // delete a value
566        this.kernel.environment.gasRefund += 15000
567        this.kernel.environment.state.del(path)
568      } else {
569        if (!valIsZero && !oldValue) {
570          // creating a new value
571          this.takeGas(15000)
572        }
573        // update
574        this.kernel.environment.state.set(path, new Vertex({
575          value: value
576        }))
577      }
578    })
579  }
580
581  /**
582   * reterives a value at a given path in long term storage
583   * @param {interger} pathOffest the memory offset to load the the path from
584   * @param {interger} resultOffset the memory offset to load the value from
585   */
586  storageLoad (pathOffset, resultOffset, cbIndex) {
587    this.takeGas(50)
588
589    // convert the path to an array
590    const path = ['storage', ...this.getMemory(pathOffset, U256_SIZE_BYTES)]
591    // get the value from the state
592    const opPromise = this.kernel.environment.state.get(path)
593      .then(vertex => vertex.value)
594      .catch(() => new Uint8Array(32))
595
596    this.kernel.pushOpsQueue(opPromise, cbIndex, value => {
597      this.setMemory(resultOffset, U256_SIZE_BYTES, value)
598    })
599  }
600
601  /**
602   * Halt execution returning output data.
603   * @param {integer} offset the offset of the output data.
604   * @param {integer} length the length of the output data.
605   */
606  return (offset, length) {
607    if (length) {
608      this.kernel.environment.returnValue = this.getMemory(offset, length).slice(0)
609    }
610  }
611
612  /**
613   * Halt execution and register account for later deletion giving the remaining
614   * balance to an address path
615   * @param {integer} offset the offset to load the address from
616   */
617  selfDestruct (addressOffset) {
618    this.kernel.environment.selfDestruct = true
619    this.kernel.environment.selfDestructAddress = this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)
620    this.kernel.environment.gasRefund += 24000
621  }
622
623  getMemory (offset, length) {
624    return new Uint8Array(this.kernel.memory, offset, length)
625  }
626
627  setMemory (offset, length, value) {
628    const memory = new Uint8Array(this.kernel.memory, offset, length)
629    memory.set(value)
630  }
631
632  /*
633   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
634   * because every caller of this method is trusted.
635   */
636  takeGas (amount) {
637    if (this.kernel.environment.gasLeft < amount) {
638      throw new Error('Ran out of gas')
639    }
640    this.kernel.environment.gasLeft -= amount
641  }
642}
643
644// converts a 64 bit number to a JS number
645function from64bit (high, low) {
646  if (high < 0) {
647    // convert from a 32-bit two's compliment
648    high = 0x100000000 - high
649  }
650  if (low < 0) {
651    // convert from a 32-bit two's compliment
652    low = 0x100000000 - low
653  }
654  // JS only bitshift 32bits, so instead of high << 32 we have high * 2 ^ 32
655  return (high * 4294967296) + low
656}
657

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