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wanderer🌟 / js-primea-hypervisor



Tree: 125f59672710cb666380d7b6804357d3da16cff4

Files: 125f59672710cb666380d7b6804357d3da16cff4 / interface.js

19233 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 Address = require('./deps/address.js')
6const U256 = require('./deps/u256.js')
7const fs = require('fs')
8const path = require('path')
9
10const U128_SIZE_BYTES = 16
11const ADDRESS_SIZE_BYTES = 20
12const U256_SIZE_BYTES = 32
13
14// The interface exposed to the WebAessembly Core
15module.exports = class Interface {
16  constructor (environment, kernel) {
17    this.kernel = kernel
18    this.environment = environment
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  get exportTable () {
32    let exportMethods = [
33      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
34      'getAddress',
35      'getBalance',
36      'getTxOrigin',
37      'getCaller',
38      'getCallValue',
39      'getCallDataSize',
40      'callDataCopy',
41      'callDataCopy256',
42      'getCodeSize',
43      'codeCopy',
44      'getExternalCodeSize',
45      'externalCodeCopy',
46      'getTxGasPrice',
47      'getBlockHash',
48      'getBlockCoinbase',
49      'getBlockTimestamp',
50      'getBlockNumber',
51      'getBlockDifficulty',
52      'getBlockGasLimit',
53      'log',
54      'create',
55      'callCode',
56      'callDelegate',
57      'storageStore',
58      'storageLoad',
59      'return',
60      'selfDestruct'
61    ]
62    let ret = {}
63    exportMethods.forEach((method) => {
64      ret[method] = this[method].bind(this)
65    })
66    return ret
67  }
68
69  setModule (mod) {
70    this.module = mod
71  }
72
73  /**
74   * Subtracts an amount to the gas counter
75   * @param {integer} amount the amount to subtract to the gas counter
76   */
77  _useGas (high, low) {
78    this.takeGas(from64bit(high, low))
79  }
80
81  /**
82   * Returns the current amount of gas
83   * @return {integer}
84   */
85  _getGasLeftHigh () {
86    return Math.floor(this.environment.gasLeft / 4294967296)
87  }
88
89  /**
90   * Returns the current amount of gas
91   * @return {integer}
92   */
93  _getGasLeftLow () {
94    return this.environment.gasLeft
95  }
96
97  /**
98   * Gets address of currently executing account and loads it into memory at
99   * the given offset.
100   * @param {integer} offset
101   */
102  getAddress (offset) {
103    this.takeGas(2)
104
105    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.address.toMemory())
106  }
107
108  /**
109   * Gets balance of the given account and loads it into memory at the given
110   * offset.
111   * @param {integer} addressOffset the memory offset to laod the address
112   * @param {integer} resultOffset
113   */
114  getBalance (addressOffset, offset) {
115    this.takeGas(20)
116
117    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
118    // call the parent contract and ask for the balance of one of its child contracts
119    const balance = this.environment.getBalance(address)
120    this.setMemory(offset, U128_SIZE_BYTES, balance.toMemory(U128_SIZE_BYTES))
121  }
122
123  /**
124   * Gets the execution's origination address and loads it into memory at the
125   * given offset. This is the sender of original transaction; it is never an
126   * account with non-empty associated code.
127   * @param {integer} offset
128   */
129  getTxOrigin (offset) {
130    this.takeGas(2)
131
132    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.origin.toMemory())
133  }
134
135  /**
136   * Gets caller address and loads it into memory at the given offset. This is
137   * the address of the account that is directly responsible for this execution.
138   * @param {integer} offset
139   */
140  getCaller (offset) {
141    this.takeGas(2)
142
143    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.caller.toMemory())
144  }
145
146  /**
147   * Gets the deposited value by the instruction/transaction responsible for
148   * this execution and loads it into memory at the given location.
149   * @param {integer} offset
150   */
151  getCallValue (offset) {
152    this.takeGas(2)
153
154    this.setMemory(offset, U128_SIZE_BYTES, this.environment.callValue.toMemory(U128_SIZE_BYTES))
155  }
156
157  /**
158   * Get size of input data in current environment. This pertains to the input
159   * data passed with the message call instruction or transaction.
160   * @return {integer}
161   */
162  getCallDataSize () {
163    this.takeGas(2)
164
165    return this.environment.callData.length
166  }
167
168  /**
169   * Copys the input data in current environment to memory. This pertains to
170   * the input data passed with the message call instruction or transaction.
171   * @param {integer} offset the offset in memory to load into
172   * @param {integer} dataOffset the offset in the input data
173   * @param {integer} length the length of data to copy
174   */
175  callDataCopy (offset, dataOffset, length) {
176    this.takeGas(3 + Math.ceil(length / 32) * 3)
177
178    if (length) {
179      const callData = this.environment.callData.slice(dataOffset, dataOffset + length)
180      this.setMemory(offset, length, callData)
181    }
182  }
183
184  /**
185   * Copys the input data in current environment to memory. This pertains to
186   * the input data passed with the message call instruction or transaction.
187   * @param {integer} offset the offset in memory to load into
188   * @param {integer} dataOffset the offset in the input data
189   */
190  callDataCopy256 (offset, dataOffset) {
191    this.takeGas(3)
192    const callData = this.environment.callData.slice(dataOffset, dataOffset + 32)
193    this.setMemory(offset, U256_SIZE_BYTES, callData)
194  }
195
196  /**
197   * Gets the size of code running in current environment.
198   * @return {interger}
199   */
200  getCodeSize () {
201    this.takeGas(2)
202
203    return this.environment.code.length
204  }
205
206  /**
207   * Copys the code running in current environment to memory.
208   * @param {integer} offset the memory offset
209   * @param {integer} codeOffset the code offset
210   * @param {integer} length the length of code to copy
211   */
212  codeCopy (resultOffset, codeOffset, length) {
213    this.takeGas(3 + Math.ceil(length / 32) * 3)
214
215    if (length) {
216      const code = this.environment.code.slice(codeOffset, codeOffset + length)
217      this.setMemory(resultOffset, length, code)
218    }
219  }
220
221  /**
222   * Get size of an account’s code.
223   * @param {integer} addressOffset the offset in memory to load the address from
224   * @return {integer}
225   */
226  getExternalCodeSize (addressOffset) {
227    this.takeGas(20)
228
229    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
230    const code = this.environment.getCode(address)
231    return code.length
232  }
233
234  /**
235   * Copys the code of an account to memory.
236   * @param {integer} addressOffset the memory offset of the address
237   * @param {integer} resultOffset the memory offset
238   * @param {integer} codeOffset the code offset
239   * @param {integer} length the length of code to copy
240   */
241  externalCodeCopy (addressOffset, resultOffset, codeOffset, length) {
242    this.takeGas(20 + Math.ceil(length / 32) * 3)
243
244    if (length) {
245      const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
246      let code = this.environment.getCode(address)
247      code = code.slice(codeOffset, codeOffset + length)
248      this.setMemory(resultOffset, length, code)
249    }
250  }
251
252  /**
253   * Gets price of gas in current environment.
254   * @return {integer}
255   */
256  getTxGasPrice () {
257    this.takeGas(2)
258
259    return this.environment.gasPrice
260  }
261
262  /**
263   * Gets the hash of one of the 256 most recent complete blocks.
264   * @param {integer} number which block to load
265   * @param {integer} offset the offset to load the hash into
266   */
267  getBlockHash (number, offset) {
268    this.takeGas(20)
269
270    const diff = this.environment.block.number - number
271    let hash
272
273    if (diff > 256 || diff <= 0) {
274      hash = new U256(0)
275    } else {
276      hash = new U256(this.environment.getBlockHash(number))
277    }
278    this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
279  }
280
281  /**
282   * Gets the block’s beneficiary address and loads into memory.
283   * @param offset
284   */
285  getBlockCoinbase (offset) {
286    this.takeGas(2)
287
288    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.environment.block.coinbase.toMemory())
289  }
290
291  /**
292   * Get the block’s timestamp.
293   * @return {integer}
294   */
295  getBlockTimestamp () {
296    this.takeGas(2)
297
298    return this.environment.block.timestamp
299  }
300
301  /**
302   * Get the block’s number.
303   * @return {integer}
304   */
305  getBlockNumber () {
306    this.takeGas(2)
307
308    return this.environment.block.number
309  }
310
311  /**
312   * Get the block’s difficulty.
313   * @return {integer}
314   */
315  getBlockDifficulty (offset) {
316    this.takeGas(2)
317
318    this.setMemory(offset, U256_SIZE_BYTES, this.environment.block.difficulty.toMemory())
319  }
320
321  /**
322   * Get the block’s gas limit.
323   * @return {integer}
324   */
325  getBlockGasLimit () {
326    this.takeGas(2)
327
328    return this.environment.block.gasLimit
329  }
330
331  /**
332   * Creates a new log in the current environment
333   * @param {integer} dataOffset the offset in memory to load the memory
334   * @param {integer} length the data length
335   * @param {integer} number of topics
336   */
337  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
338    if (numberOfTopics < 0 || numberOfTopics > 4) {
339      throw new Error('Invalid numberOfTopics')
340    }
341
342    this.takeGas(375 + length * 8 + numberOfTopics * 375)
343
344    const data = length ? this.getMemory(dataOffset, length).slice(0) : new Uint8Array([])
345    const topics = []
346
347    if (numberOfTopics > 0) {
348      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
349    }
350
351    if (numberOfTopics > 1) {
352      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
353    }
354
355    if (numberOfTopics > 2) {
356      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
357    }
358
359    if (numberOfTopics > 3) {
360      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
361    }
362
363    this.environment.logs.push({
364      data: data,
365      topics: topics
366    })
367  }
368
369  /**
370   * Creates a new contract with a given value.
371   * @param {integer} valueOffset the offset in memory to the value from
372   * @param {integer} dataOffset the offset to load the code for the new contract from
373   * @param {integer} length the data length
374   * @param (integer} resultOffset the offset to write the new contract address to
375   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
376   */
377  create (valueOffset, dataOffset, length, resultOffset) {
378    this.takeGas(32000)
379
380    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
381    if (length) {
382      const data = this.getMemory(dataOffset, length).slice(0)
383      // const [errorCode, address] = this.environment.create(value, data)
384    }
385    let address
386    if (value.gt(this.environment.value)) {
387      address = new Address()
388    } else {
389      address = new Address('0x945304eb96065b2a98b57a48a06ae28d285a71b5')
390    }
391    this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address.toMemory())
392    // return errorCode
393  }
394
395  /**
396   * Sends a message with arbiatary data to a given address path
397   * @param {integer} addressOffset the offset to load the address path from
398   * @param {integer} valueOffset the offset to load the value from
399   * @param {integer} dataOffset the offset to load data from
400   * @param {integer} dataLength the length of data
401   * @param {integer} resultOffset the offset to store the result data at
402   * @param {integer} resultLength
403   * @param {integer} gas
404   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
405   */
406  _call (gasHigh, gasLow, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
407    const gas = from64bit(gasHigh, gasLow)
408    // Load the params from mem
409    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
410    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
411
412    this.takeGas(40)
413
414    // const data = this.getMemory(dataOffset, dataLength).slice(0)
415
416    // // Special case for calling into empty account
417    // if (!this.environment.isAccountPresent(address)) {
418    //   this.takeGas(25000)
419    // }
420    if (address.lt(new U256(4))) {
421      this.takeGas(25000)
422    }
423    // // Special case for non-zero value
424    if (!value.isZero()) {
425      this.takeGas(9000 - 2300 + gas)
426      this.takeGas(-gas)
427    }
428
429    // const [errorCode, result] = this.environment.call(gas, address, value, data)
430    // this.setMemory(resultOffset, resultLength, result)
431    // return errorCode
432    //
433    return 1
434  }
435
436  /**
437   * Message-call into this account with an alternative account’s code.
438   * @param {integer} addressOffset the offset to load the address path from
439   * @param {integer} valueOffset the offset to load the value from
440   * @param {integer} dataOffset the offset to load data from
441   * @param {integer} dataLength the length of data
442   * @param {integer} resultOffset the offset to store the result data at
443   * @param {integer} resultLength
444   * @param {integer} gas
445   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
446   */
447  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
448    // Load the params from mem
449    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
450    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
451
452    this.takeGas(40)
453
454    // const data = this.getMemory(dataOffset, dataLength).slice(0)
455
456    // // Special case for calling into empty account
457    // if (!this.environment.isAccountPresent(address)) {
458    //   this.takeGas(25000)
459    // }
460    // // Special case for non-zero value
461    if (!value.isZero()) {
462      this.takeGas(9000 - 2300 + gas)
463      this.takeGas(-gas)
464    }
465
466    // const [errorCode, result] = this.environment.call(gas, address, value, data)
467    // this.setMemory(resultOffset, resultLength, result)
468    // return errorCode
469    //
470    return 1
471  }
472
473  /**
474   * Message-call into this account with an alternative account’s code, but
475   * persisting the current values for sender and value.
476   * @param {integer} gas
477   * @param {integer} addressOffset the offset to load the address path from
478   * @param {integer} valueOffset the offset to load the value from
479   * @param {integer} dataOffset the offset to load data from
480   * @param {integer} dataLength the length of data
481   * @param {integer} resultOffset the offset to store the result data at
482   * @param {integer} resultLength
483   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
484   */
485  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
486    // FIXME: count properly
487    this.takeGas(40)
488
489    const data = this.getMemory(dataOffset, dataLength).slice(0)
490    const address = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
491    const [errorCode, result] = this.environment.callDelegate(gas, address, data)
492    this.setMemory(resultOffset, resultLength, result)
493    return errorCode
494  }
495
496  /**
497   * store a value at a given path in long term storage which are both loaded
498   * from Memory
499   * @param {interger} pathOffest the memory offset to load the the path from
500   * @param {interger} valueOffset the memory offset to load the value from
501   */
502  storageStore (pathOffset, valueOffset, cbDest) {
503    this.takeGas(5000)
504    const path = [...this.getMemory(pathOffset, U256_SIZE_BYTES)]
505    // copy the value
506    const value = this.getMemory(valueOffset, U256_SIZE_BYTES).slice(0)
507    const valIsZero = value.every((i) => i === 0)
508    const opPromise = this.environment.state.get(path)
509    .catch(() => {
510      // TODO: handle errors
511      // the value was not found
512      return null
513    })
514
515    // wait for all the prevouse async ops to finish before running the callback
516    this.kernel._runningOps = Promise.all([this.kernel._runningOps, opPromise])
517    .then(values => {
518      const oldValue = values.pop()
519      if (valIsZero && oldValue) {
520        // delete a value
521        this.environment.gasRefund += 15000
522        this.environment.state.del(path)
523      } else {
524        if (!valIsZero && !oldValue) {
525          // creating a new value
526          this.takeGas(15000)
527        }
528        // update
529        this.environment.state.set(path, value)
530      }
531
532      this.module.exports[cbDest.toString()]()
533    })
534  }
535
536  /**
537   * reterives a value at a given path in long term storage
538   * @param {interger} pathOffest the memory offset to load the the path from
539   * @param {interger} resultOffset the memory offset to load the value from
540   */
541  storageLoad (pathOffset, resultOffset, cbDest) {
542    this.takeGas(50)
543
544    // convert the path to an array
545    const path = [...this.getMemory(pathOffset, U256_SIZE_BYTES)]
546    const opPromise = this.environment.state.get(path)
547    .catch(() => {
548      // TODO: handle other possible errors
549      // if the value was not found return a empty array
550      return new Uint8Array(32)
551    })
552
553    // wait for all the prevouse async ops to finish before running the callback
554    this.kernel._runningOps = Promise
555    .all([this.kernel._runningOps, opPromise])
556    .then(values => {
557      const result = values.pop()
558      this.setMemory(resultOffset, U256_SIZE_BYTES, result)
559      this.module.exports[cbDest.toString()]()
560    })
561  }
562
563  /**
564   * Halt execution returning output data.
565   * @param {integer} offset the offset of the output data.
566   * @param {integer} length the length of the output data.
567   */
568  return (offset, length) {
569    if (length) {
570      this.environment.returnValue = this.getMemory(offset, length).slice(0)
571    }
572  }
573
574  /**
575   * Halt execution and register account for later deletion giving the remaining
576   * balance to an address path
577   * @param {integer} offset the offset to load the address from
578   */
579  selfDestruct (addressOffset) {
580    this.environment.selfDestruct = true
581    this.environment.selfDestructAddress = Address.fromMemory(this.getMemory(addressOffset, ADDRESS_SIZE_BYTES))
582    this.environment.gasRefund += 24000
583  }
584
585  getMemory (offset, length) {
586    return new Uint8Array(this.module.exports.memory, offset, length)
587  }
588
589  setMemory (offset, length, value) {
590    const memory = new Uint8Array(this.module.exports.memory, offset, length)
591    memory.set(value)
592  }
593
594  /*
595   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
596   * because every caller of this method is trusted.
597   */
598  takeGas (amount) {
599    if (this.environment.gasLeft < amount) {
600      throw new Error('Ran out of gas')
601    }
602    this.environment.gasLeft -= amount
603  }
604}
605
606// converts a 64 bit number to a JS number
607function from64bit (high, low) {
608  if (high < 0) {
609    // convert from a 32-bit two's compliment
610    high = 0x100000000 - high
611  }
612  if (low < 0) {
613    // convert from a 32-bit two's compliment
614    low = 0x100000000 - low
615  }
616  // JS only bitshift 32bits, so instead of high << 32 we have high * 2 ^ 32
617  return (high * 4294967296) + low
618}
619

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