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wanderer🌟 / js-primea-hypervisor



Tree: 218378ee81f2cf20c03ed1333553072db9dd4205

Files: 218378ee81f2cf20c03ed1333553072db9dd4205 / 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 */
5
6const Vertex = require('merkle-trie')
7const Address = require('./deps/address.js')
8const U256 = require('./deps/u256.js')
9const fs = require('fs')
10const path = require('path')
11
12const U128_SIZE_BYTES = 16
13const ADDRESS_SIZE_BYTES = 20
14const U256_SIZE_BYTES = 32
15
16// The interface exposed to the WebAessembly Core
17module.exports = class Interface {
18  constructor (kernel) {
19    this.kernel = kernel
20    const shimBin = fs.readFileSync(path.join(__dirname, '/wasm/interface.wasm'))
21    const shimMod = WebAssembly.Module(shimBin)
22    this.shims = WebAssembly.Instance(shimMod, {
23      'interface': {
24        'useGas': this._useGas.bind(this),
25        'getGasLeftHigh': this._getGasLeftHigh.bind(this),
26        'getGasLeftLow': this._getGasLeftLow.bind(this),
27        'call': this._call.bind(this)
28      }
29    })
30  }
31
32  static get name () {
33    return 'ethereum'
34  }
35
36  get exports () {
37    let exportMethods = [
38      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
39      'getAddress',
40      'getBalance',
41      'getTxOrigin',
42      'getCaller',
43      'getCallValue',
44      'getCallDataSize',
45      'callDataCopy',
46      'callDataCopy256',
47      'getCodeSize',
48      'codeCopy',
49      'getExternalCodeSize',
50      'externalCodeCopy',
51      'getTxGasPrice',
52      'getBlockHash',
53      'getBlockCoinbase',
54      'getBlockTimestamp',
55      'getBlockNumber',
56      'getBlockDifficulty',
57      'getBlockGasLimit',
58      'log',
59      'create',
60      'callCode',
61      'callDelegate',
62      'storageStore',
63      'storageLoad',
64      'return',
65      'selfDestruct'
66    ]
67    let ret = {}
68    exportMethods.forEach((method) => {
69      ret[method] = this[method].bind(this)
70    })
71
72    // add shims
73    ret.useGas = this.shims.exports.useGas
74    ret.getGasLeft = this.shims.exports.getGasLeft
75    ret.call = this.shims.exports.call
76    return ret
77  }
78
79  setModule (mod) {
80    this.module = mod
81  }
82
83  /**
84   * Subtracts an amount to the gas counter
85   * @param {integer} amount the amount to subtract to the gas counter
86   */
87  _useGas (high, low) {
88    this.takeGas(from64bit(high, low))
89  }
90
91  /**
92   * Returns the current amount of gas
93   * @return {integer}
94   */
95  _getGasLeftHigh () {
96    return Math.floor(this.kernel.environment.gasLeft / 4294967296)
97  }
98
99  /**
100   * Returns the current amount of gas
101   * @return {integer}
102   */
103  _getGasLeftLow () {
104    return this.kernel.environment.gasLeft
105  }
106
107  /**
108   * Gets address of currently executing account and loads it into memory at
109   * the given offset.
110   * @param {integer} offset
111   */
112  getAddress (offset) {
113    this.takeGas(2)
114
115    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.address.toMemory())
116  }
117
118  /**
119   * Gets balance of the given account and loads it into memory at the given
120   * offset.
121   * @param {integer} addressOffset the memory offset to laod the address
122   * @param {integer} resultOffset
123   */
124  getBalance (addressOffset, offset, cbIndex) {
125    this.takeGas(20)
126
127    const path = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'balance']
128    const opPromise = this.kernel.environment.state.root.get(path)
129      .then(vertex => new U256(vertex.value))
130      .catch(() => new U256(0))
131
132    this.kernel.pushOpsQueue(opPromise, cbIndex, balance => {
133      this.setMemory(offset, U128_SIZE_BYTES, balance.toMemory(U128_SIZE_BYTES))
134    })
135  }
136
137  /**
138   * Gets the execution's origination address and loads it into memory at the
139   * given offset. This is the sender of original transaction; it is never an
140   * account with non-empty associated code.
141   * @param {integer} offset
142   */
143  getTxOrigin (offset) {
144    this.takeGas(2)
145
146    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.origin.toMemory())
147  }
148
149  /**
150   * Gets caller address and loads it into memory at the given offset. This is
151   * the address of the account that is directly responsible for this execution.
152   * @param {integer} offset
153   */
154  getCaller (offset) {
155    this.takeGas(2)
156
157    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.caller.toMemory())
158  }
159
160  /**
161   * Gets the deposited value by the instruction/transaction responsible for
162   * this execution and loads it into memory at the given location.
163   * @param {integer} offset
164   */
165  getCallValue (offset) {
166    this.takeGas(2)
167
168    this.setMemory(offset, U128_SIZE_BYTES, this.kernel.environment.callValue.toMemory(U128_SIZE_BYTES))
169  }
170
171  /**
172   * Get size of input data in current environment. This pertains to the input
173   * data passed with the message call instruction or transaction.
174   * @return {integer}
175   */
176  getCallDataSize () {
177    this.takeGas(2)
178
179    return this.kernel.environment.callData.length
180  }
181
182  /**
183   * Copys the input data in current environment to memory. This pertains to
184   * the input data passed with the message call instruction or transaction.
185   * @param {integer} offset the offset in memory to load into
186   * @param {integer} dataOffset the offset in the input data
187   * @param {integer} length the length of data to copy
188   */
189  callDataCopy (offset, dataOffset, length) {
190    this.takeGas(3 + Math.ceil(length / 32) * 3)
191
192    if (length) {
193      const callData = this.kernel.environment.callData.slice(dataOffset, dataOffset + length)
194      this.setMemory(offset, length, callData)
195    }
196  }
197
198  /**
199   * Copys the input data in current environment to memory. This pertains to
200   * the input data passed with the message call instruction or transaction.
201   * @param {integer} offset the offset in memory to load into
202   * @param {integer} dataOffset the offset in the input data
203   */
204  callDataCopy256 (offset, dataOffset) {
205    this.takeGas(3)
206    const callData = this.kernel.environment.callData.slice(dataOffset, dataOffset + 32)
207    this.setMemory(offset, U256_SIZE_BYTES, callData)
208  }
209
210  /**
211   * Gets the size of code running in current environment.
212   * @return {interger}
213   */
214  getCodeSize () {
215    this.takeGas(2)
216
217    return this.kernel.environment.code.length
218  }
219
220  /**
221   * Copys the code running in current environment to memory.
222   * @param {integer} offset the memory offset
223   * @param {integer} codeOffset the code offset
224   * @param {integer} length the length of code to copy
225   */
226  codeCopy (resultOffset, codeOffset, length) {
227    this.takeGas(3 + Math.ceil(length / 32) * 3)
228
229    if (length) {
230      const code = this.kernel.environment.code.slice(codeOffset, codeOffset + length)
231      this.setMemory(resultOffset, length, code)
232    }
233  }
234
235  /**
236   * Get size of an account’s code.
237   * @param {integer} addressOffset the offset in memory to load the address from
238   * @return {integer}
239   */
240  getExternalCodeSize (addressOffset, cbOffset) {
241    this.takeGas(20)
242    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
243    const opPromise = this.kernel.environment.state.root.get(address)
244      .then(vertex => vertex.value.length)
245      .catch(() => 0)
246
247    // wait for all the prevouse async ops to finish before running the callback
248    this.kernel.pushOpsQueue(opPromise, cbOffset, length => length)
249  }
250
251  /**
252   * Copys the code of an account to memory.
253   * @param {integer} addressOffset the memory offset of the address
254   * @param {integer} resultOffset the memory offset
255   * @param {integer} codeOffset the code offset
256   * @param {integer} length the length of code to copy
257   */
258  externalCodeCopy (addressOffset, resultOffset, codeOffset, length) {
259    this.takeGas(20 + Math.ceil(length / 32) * 3)
260
261    if (length) {
262      const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
263      let code = this.kernel.environment.getCode(address)
264      code = code.slice(codeOffset, codeOffset + length)
265      this.setMemory(resultOffset, length, code)
266    }
267  }
268
269  /**
270   * Gets price of gas in current environment.
271   * @return {integer}
272   */
273  getTxGasPrice () {
274    this.takeGas(2)
275
276    return this.kernel.environment.gasPrice
277  }
278
279  /**
280   * Gets the hash of one of the 256 most recent complete blocks.
281   * @param {integer} number which block to load
282   * @param {integer} offset the offset to load the hash into
283   */
284  getBlockHash (number, offset, cbOffset) {
285    this.takeGas(20)
286
287    const diff = this.kernel.environment.block.number - number
288    let opPromise
289
290    if (diff > 256 || diff <= 0) {
291      opPromise = Promise.resolve(new U256(0))
292    } else {
293      opPromise = this.kernel.environment.getBlockHash(number)
294    }
295
296    // wait for all the prevouse async ops to finish before running the callback
297    this.kernel.pushOpsQueue(opPromise, cbOffset, hash => {
298      this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
299    })
300  }
301
302  /**
303   * Gets the block’s beneficiary address and loads into memory.
304   * @param offset
305   */
306  getBlockCoinbase (offset) {
307    this.takeGas(2)
308
309    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.block.coinbase.toMemory())
310  }
311
312  /**
313   * Get the block’s timestamp.
314   * @return {integer}
315   */
316  getBlockTimestamp () {
317    this.takeGas(2)
318
319    return this.kernel.environment.block.timestamp
320  }
321
322  /**
323   * Get the block’s number.
324   * @return {integer}
325   */
326  getBlockNumber () {
327    this.takeGas(2)
328
329    return this.kernel.environment.block.number
330  }
331
332  /**
333   * Get the block’s difficulty.
334   * @return {integer}
335   */
336  getBlockDifficulty (offset) {
337    this.takeGas(2)
338
339    this.setMemory(offset, U256_SIZE_BYTES, this.kernel.environment.block.difficulty.toMemory())
340  }
341
342  /**
343   * Get the block’s gas limit.
344   * @return {integer}
345   */
346  getBlockGasLimit () {
347    this.takeGas(2)
348
349    return this.kernel.environment.block.gasLimit
350  }
351
352  /**
353   * Creates a new log in the current environment
354   * @param {integer} dataOffset the offset in memory to load the memory
355   * @param {integer} length the data length
356   * @param {integer} number of topics
357   */
358  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
359    if (numberOfTopics < 0 || numberOfTopics > 4) {
360      throw new Error('Invalid numberOfTopics')
361    }
362
363    this.takeGas(375 + length * 8 + numberOfTopics * 375)
364
365    const data = length ? this.getMemory(dataOffset, length).slice(0) : new Uint8Array([])
366    const topics = []
367
368    if (numberOfTopics > 0) {
369      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
370    }
371
372    if (numberOfTopics > 1) {
373      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
374    }
375
376    if (numberOfTopics > 2) {
377      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
378    }
379
380    if (numberOfTopics > 3) {
381      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
382    }
383
384    this.kernel.environment.logs.push({
385      data: data,
386      topics: topics
387    })
388  }
389
390  /**
391   * Creates a new contract with a given value.
392   * @param {integer} valueOffset the offset in memory to the value from
393   * @param {integer} dataOffset the offset to load the code for the new contract from
394   * @param {integer} length the data length
395   * @param (integer} resultOffset the offset to write the new contract address to
396   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
397   */
398  create (valueOffset, dataOffset, length, resultOffset) {
399    this.takeGas(32000)
400
401    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
402    if (length) {
403      const data = this.getMemory(dataOffset, length).slice(0)
404      // const [errorCode, address] = this.environment.create(value, data)
405    }
406    let address
407    if (value.gt(this.kernel.environment.value)) {
408      address = new Address()
409    } else {
410      address = new Address('0x945304eb96065b2a98b57a48a06ae28d285a71b5')
411    }
412    this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address.toMemory())
413    // return errorCode
414  }
415
416  /**
417   * Sends a message with arbiatary data to a given address path
418   * @param {integer} addressOffset the offset to load the address path from
419   * @param {integer} valueOffset the offset to load the value from
420   * @param {integer} dataOffset the offset to load data from
421   * @param {integer} dataLength the length of data
422   * @param {integer} resultOffset the offset to store the result data at
423   * @param {integer} resultLength
424   * @param {integer} gas
425   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
426   */
427  _call (gasHigh, gasLow, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
428    const gas = from64bit(gasHigh, gasLow)
429    // Load the params from mem
430    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
431    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
432
433    this.takeGas(40)
434
435    // const data = this.getMemory(dataOffset, dataLength).slice(0)
436
437    // // Special case for calling into empty account
438    // if (!this.environment.isAccountPresent(address)) {
439    //   this.takeGas(25000)
440    // }
441    if (address.lt(new U256(4))) {
442      this.takeGas(25000)
443    }
444    // // Special case for non-zero value
445    if (!value.isZero()) {
446      this.takeGas(9000 - 2300 + gas)
447      this.takeGas(-gas)
448    }
449
450    // const [errorCode, result] = this.environment.call(gas, address, value, data)
451    // this.setMemory(resultOffset, resultLength, result)
452    // return errorCode
453    //
454    return 1
455  }
456
457  /**
458   * Message-call into this account with an alternative account’s code.
459   * @param {integer} addressOffset the offset to load the address path from
460   * @param {integer} valueOffset the offset to load the value from
461   * @param {integer} dataOffset the offset to load data from
462   * @param {integer} dataLength the length of data
463   * @param {integer} resultOffset the offset to store the result data at
464   * @param {integer} resultLength
465   * @param {integer} gas
466   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
467   */
468  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
469    this.takeGas(40)
470    // Load the params from mem
471    const path = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
472    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
473
474    // Special case for non-zero value
475    if (!value.isZero()) {
476      this.takeGas(6700)
477    }
478
479    // TODO: should be message?
480    const opPromise = this.kernel.environment.state.root.get(path)
481    .catch(() => {
482      // TODO: handle errors
483      // the value was not found
484      return null
485    })
486
487    this.kernel.pushOpsQueue(opPromise, cbIndex, oldValue => {
488      //TODO
489      // const data = this.getMemory(dataOffset, dataLength).slice(0)
490
491      // // Special case for calling into empty account
492      // if (!this.environment.isAccountPresent(address)) {
493      //   this.takeGas(25000)
494      // }
495
496      // const [errorCode, result] = this.environment.call(gas, address, value, data)
497      // this.setMemory(resultOffset, resultLength, result)
498      // return errorCode
499      //
500    })
501  }
502
503  /**
504   * Message-call into this account with an alternative account’s code, but
505   * persisting the current values for sender and value.
506   * @param {integer} gas
507   * @param {integer} addressOffset the offset to load the address path from
508   * @param {integer} valueOffset the offset to load the value from
509   * @param {integer} dataOffset the offset to load data from
510   * @param {integer} dataLength the length of data
511   * @param {integer} resultOffset the offset to store the result data at
512   * @param {integer} resultLength
513   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
514   */
515  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
516    // FIXME: count properly
517    this.takeGas(40)
518
519    const data = this.getMemory(dataOffset, dataLength).slice(0)
520    const address = [...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
521    const [errorCode, result] = this.environment.callDelegate(gas, address, data)
522    this.setMemory(resultOffset, resultLength, result)
523    return errorCode
524  }
525
526  /**
527   * store a value at a given path in long term storage which are both loaded
528   * from Memory
529   * @param {interger} pathOffest the memory offset to load the the path from
530   * @param {interger} valueOffset the memory offset to load the value from
531   */
532  storageStore (pathOffset, valueOffset, cbIndex) {
533    this.takeGas(5000)
534    const path = ['storage', ...this.getMemory(pathOffset, U256_SIZE_BYTES)]
535    // copy the value
536    const value = this.getMemory(valueOffset, U256_SIZE_BYTES).slice(0)
537    const valIsZero = value.every((i) => i === 0)
538    const opPromise = this.kernel.environment.state.get(path)
539      .then(vertex => vertex.value)
540      .catch(() => null)
541
542    this.kernel.pushOpsQueue(opPromise, cbIndex, oldValue => {
543      if (valIsZero && oldValue) {
544        // delete a value
545        this.kernel.environment.gasRefund += 15000
546        this.kernel.environment.state.del(path)
547      } else {
548        if (!valIsZero && !oldValue) {
549          // creating a new value
550          this.takeGas(15000)
551        }
552        // update
553        this.kernel.environment.state.set(path, new Vertex({
554          value: value
555        }))
556      }
557    })
558  }
559
560  /**
561   * reterives a value at a given path in long term storage
562   * @param {interger} pathOffest the memory offset to load the the path from
563   * @param {interger} resultOffset the memory offset to load the value from
564   */
565  storageLoad (pathOffset, resultOffset, cbIndex) {
566    this.takeGas(50)
567
568    // convert the path to an array
569    const path = ['storage', ...this.getMemory(pathOffset, U256_SIZE_BYTES)]
570    // get the value from the state
571    const opPromise = this.kernel.environment.state.get(path)
572      .then(vertex => vertex.value)
573      .catch(() => new Uint8Array(32))
574
575    this.kernel.pushOpsQueue(opPromise, cbIndex, value => {
576      this.setMemory(resultOffset, U256_SIZE_BYTES, value)
577    })
578  }
579
580  /**
581   * Halt execution returning output data.
582   * @param {integer} offset the offset of the output data.
583   * @param {integer} length the length of the output data.
584   */
585  return (offset, length) {
586    if (length) {
587      this.kernel.environment.returnValue = this.getMemory(offset, length).slice(0)
588    }
589  }
590
591  /**
592   * Halt execution and register account for later deletion giving the remaining
593   * balance to an address path
594   * @param {integer} offset the offset to load the address from
595   */
596  selfDestruct (addressOffset) {
597    this.kernel.environment.selfDestruct = true
598    this.kernel.environment.selfDestructAddress = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
599    this.kernel.environment.gasRefund += 24000
600  }
601
602  getMemory (offset, length) {
603    return new Uint8Array(this.kernel.memory, offset, length)
604  }
605
606  setMemory (offset, length, value) {
607    const memory = new Uint8Array(this.kernel.memory, offset, length)
608    memory.set(value)
609  }
610
611  /*
612   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
613   * because every caller of this method is trusted.
614   */
615  takeGas (amount) {
616    if (this.kernel.environment.gasLeft < amount) {
617      throw new Error('Ran out of gas')
618    }
619    this.kernel.environment.gasLeft -= amount
620  }
621}
622
623// converts a 64 bit number to a JS number
624function from64bit (high, low) {
625  if (high < 0) {
626    // convert from a 32-bit two's compliment
627    high = 0x100000000 - high
628  }
629  if (low < 0) {
630    // convert from a 32-bit two's compliment
631    low = 0x100000000 - low
632  }
633  // JS only bitshift 32bits, so instead of high << 32 we have high * 2 ^ 32
634  return (high * 4294967296) + low
635}
636

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