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wanderer🌟 / js-primea-hypervisor



Tree: de87b9b68f0638e5deda64385e6c49c506325b8e

Files: de87b9b68f0638e5deda64385e6c49c506325b8e / EVMimports.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 = ['accounts', ...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 > 0 && offset >= 0 && dataOffset >= 0) {
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
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 (cbIndex) {
215    this.takeGas(2)
216
217    const opPromise = this.kernel.environment.state
218      .get('code')
219      .then(vertex => vertex.value.length)
220
221    // wait for all the prevouse async ops to finish before running the callback
222    this.kernel.pushOpsQueue(opPromise, cbIndex, length => length)
223  }
224
225  /**
226   * Copys the code running in current environment to memory.
227   * @param {integer} offset the memory offset
228   * @param {integer} codeOffset the code offset
229   * @param {integer} length the length of code to copy
230   */
231  codeCopy (resultOffset, codeOffset, length, cbIndex) {
232    this.takeGas(3 + Math.ceil(length / 32) * 3)
233
234    let opPromise
235
236    if (length) {
237      opPromise = this.kernel.environment.state
238        .get('code')
239        .then(vertex => vertex.value)
240    } else {
241      opPromise = Promise.resolve([])
242    }
243
244    // wait for all the prevouse async ops to finish before running the callback
245    this.kernel.pushOpsQueue(opPromise, cbIndex, code => {
246      if (code.length) {
247        code = code.slice(codeOffset, codeOffset + length)
248        this.setMemory(resultOffset, length, code)
249      }
250    })
251  }
252
253  /**
254   * Get size of an account’s code.
255   * @param {integer} addressOffset the offset in memory to load the address from
256   * @return {integer}
257   */
258  getExternalCodeSize (addressOffset, cbOffset) {
259    this.takeGas(20)
260    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
261    const opPromise = this.kernel.environment.state.root
262      .get(address)
263      .then(vertex => vertex.value.length)
264      .catch(() => 0)
265
266    // wait for all the prevouse async ops to finish before running the callback
267    this.kernel.pushOpsQueue(opPromise, cbOffset, length => length)
268  }
269
270  /**
271   * Copys the code of an account to memory.
272   * @param {integer} addressOffset the memory offset of the address
273   * @param {integer} resultOffset the memory offset
274   * @param {integer} codeOffset the code offset
275   * @param {integer} length the length of code to copy
276   */
277  externalCodeCopy (addressOffset, resultOffset, codeOffset, length, cbIndex) {
278    this.takeGas(20 + Math.ceil(length / 32) * 3)
279
280    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES), 'code']
281    let opPromise
282
283    if (length) {
284      opPromise = this.kernel.environment.state.root
285        .get(address)
286        .then(vertex => vertex.value)
287        .catch(() => [])
288    } else {
289      opPromise = Promise.resolve([])
290    }
291
292    // wait for all the prevouse async ops to finish before running the callback
293    this.kernel.pushOpsQueue(opPromise, cbIndex, code => {
294      if (code.length) {
295        code = code.slice(codeOffset, codeOffset + length)
296        this.setMemory(resultOffset, length, code)
297      }
298    })
299  }
300
301  /**
302   * Gets price of gas in current environment.
303   * @return {integer}
304   */
305  getTxGasPrice () {
306    this.takeGas(2)
307
308    return this.kernel.environment.gasPrice
309  }
310
311  /**
312   * Gets the hash of one of the 256 most recent complete blocks.
313   * @param {integer} number which block to load
314   * @param {integer} offset the offset to load the hash into
315   */
316  getBlockHash (number, offset, cbOffset) {
317    this.takeGas(20)
318
319    const diff = this.kernel.environment.block.number - number
320    let opPromise
321
322    if (diff > 256 || diff <= 0) {
323      opPromise = Promise.resolve(new U256(0))
324    } else {
325      opPromise = this.kernel.environment.getBlockHash(number)
326    }
327
328    // wait for all the prevouse async ops to finish before running the callback
329    this.kernel.pushOpsQueue(opPromise, cbOffset, hash => {
330      this.setMemory(offset, U256_SIZE_BYTES, hash.toMemory())
331    })
332  }
333
334  /**
335   * Gets the block’s beneficiary address and loads into memory.
336   * @param offset
337   */
338  getBlockCoinbase (offset) {
339    this.takeGas(2)
340
341    this.setMemory(offset, ADDRESS_SIZE_BYTES, this.kernel.environment.block.header.coinbase)
342  }
343
344  /**
345   * Get the block’s timestamp.
346   * @return {integer}
347   */
348  getBlockTimestamp () {
349    this.takeGas(2)
350
351    return this.kernel.environment.block.timestamp
352  }
353
354  /**
355   * Get the block’s number.
356   * @return {integer}
357   */
358  getBlockNumber () {
359    this.takeGas(2)
360
361    return this.kernel.environment.block.number
362  }
363
364  /**
365   * Get the block’s difficulty.
366   * @return {integer}
367   */
368  getBlockDifficulty (offset) {
369    this.takeGas(2)
370
371    this.setMemory(offset, U256_SIZE_BYTES, this.kernel.environment.block.difficulty.toMemory())
372  }
373
374  /**
375   * Get the block’s gas limit.
376   * @return {integer}
377   */
378  getBlockGasLimit () {
379    this.takeGas(2)
380
381    return this.kernel.environment.block.gasLimit
382  }
383
384  /**
385   * Creates a new log in the current environment
386   * @param {integer} dataOffset the offset in memory to load the memory
387   * @param {integer} length the data length
388   * @param {integer} number of topics
389   */
390  log (dataOffset, length, numberOfTopics, topic1, topic2, topic3, topic4) {
391    if (numberOfTopics < 0 || numberOfTopics > 4) {
392      throw new Error('Invalid numberOfTopics')
393    }
394
395    this.takeGas(375 + length * 8 + numberOfTopics * 375)
396
397    const data = length ? this.getMemory(dataOffset, length).slice(0) : new Uint8Array([])
398    const topics = []
399
400    if (numberOfTopics > 0) {
401      topics.push(U256.fromMemory(this.getMemory(topic1, U256_SIZE_BYTES)))
402    }
403
404    if (numberOfTopics > 1) {
405      topics.push(U256.fromMemory(this.getMemory(topic2, U256_SIZE_BYTES)))
406    }
407
408    if (numberOfTopics > 2) {
409      topics.push(U256.fromMemory(this.getMemory(topic3, U256_SIZE_BYTES)))
410    }
411
412    if (numberOfTopics > 3) {
413      topics.push(U256.fromMemory(this.getMemory(topic4, U256_SIZE_BYTES)))
414    }
415
416    this.kernel.environment.logs.push({
417      data: data,
418      topics: topics
419    })
420  }
421
422  /**
423   * Creates a new contract with a given value.
424   * @param {integer} valueOffset the offset in memory to the value from
425   * @param {integer} dataOffset the offset to load the code for the new contract from
426   * @param {integer} length the data length
427   * @param (integer} resultOffset the offset to write the new contract address to
428   * @return {integer} Return 1 or 0 depending on if the VM trapped on the message or not
429   */
430  create (valueOffset, dataOffset, length, resultOffset, cbIndex) {
431    this.takeGas(32000)
432
433    const value = U256.fromMemory(this.getMemory(valueOffset, U128_SIZE_BYTES))
434    // if (length) {
435    //   const code = this.getMemory(dataOffset, length).slice(0)
436    // }
437
438    let opPromise
439
440    if (value.gt(this.kernel.environment.value)) {
441      opPromise = Promise.resolve(new Buffer(20).fill(0))
442    } else {
443      // todo actully run the code
444      opPromise = Promise.resolve(ethUtil.generateAddress(this.kernel.environment.address, this.kernel.environment.nonce))
445    }
446
447    // wait for all the prevouse async ops to finish before running the callback
448    this.kernel.pushOpsQueue(opPromise, cbIndex, address => {
449      this.setMemory(resultOffset, ADDRESS_SIZE_BYTES, address)
450    })
451  }
452
453  /**
454   * Sends a message with arbiatary data to a given address path
455   * @param {integer} addressOffset the offset to load the address path from
456   * @param {integer} valueOffset the offset to load the value from
457   * @param {integer} dataOffset the offset to load data from
458   * @param {integer} dataLength the length of data
459   * @param {integer} resultOffset the offset to store the result data at
460   * @param {integer} resultLength
461   * @param {integer} gas
462   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
463   */
464  _call (gasHigh, gasLow, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength, cbIndex) {
465    this.takeGas(40)
466
467    const gas = from64bit(gasHigh, gasLow)
468    // Load the params from mem
469    const address = ['accounts', ...this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)]
470    const value = new U256(this.getMemory(valueOffset, U128_SIZE_BYTES))
471
472    // Special case for non-zero value; why does this exist?
473    if (!value.isZero()) {
474      this.takeGas(9000 - 2300 + gas)
475      this.takeGas(-gas)
476    }
477
478    let opPromise = this.kernel.environment.state.root.get(address)
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.kernel.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.kernel.environment.state.root.get(path)
514    .catch(() => {
515      // TODO: handle errors
516      // the value was not found
517      return null
518    })
519
520    this.kernel.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 = ['storage', ...this.getMemory(pathOffset, U256_SIZE_BYTES)]
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.environment.state.get(path)
561      .then(vertex => vertex.value)
562      .catch(() => null)
563
564    this.kernel.pushOpsQueue(opPromise, cbIndex, oldValue => {
565      if (valIsZero && oldValue) {
566        // delete a value
567        this.kernel.environment.gasRefund += 15000
568        this.kernel.environment.state.del(path)
569      } else {
570        if (!valIsZero && !oldValue) {
571          // creating a new value
572          this.takeGas(15000)
573        }
574        // update
575        this.kernel.environment.state.set(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 = ['storage', ...this.getMemory(pathOffset, U256_SIZE_BYTES)]
592    // get the value from the state
593    const opPromise = this.kernel.environment.state.get(path)
594      .then(vertex => vertex.value)
595      .catch(() => new Uint8Array(32))
596
597    this.kernel.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    this.kernel.environment.returnValue = this.getMemory(offset, length).slice(0)
609  }
610
611  /**
612   * Halt execution and register account for later deletion giving the remaining
613   * balance to an address path
614   * @param {integer} offset the offset to load the address from
615   */
616  selfDestruct (addressOffset) {
617    this.kernel.environment.selfDestruct = true
618    this.kernel.environment.selfDestructAddress = this.getMemory(addressOffset, ADDRESS_SIZE_BYTES)
619    this.kernel.environment.gasRefund += 24000
620  }
621
622  getMemory (offset, length) {
623    if (offset >= 0 && length > 0) {
624      return new Uint8Array(this.kernel.memory, offset, length)
625    } else {
626      return new Uint8Array([])
627    }
628  }
629
630  setMemory (offset, length, value) {
631    if (offset >= 0 && length > 0) {
632      const memory = new Uint8Array(this.kernel.memory, offset, length)
633      memory.set(value)
634    }
635  }
636
637  /*
638   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
639   * because every caller of this method is trusted.
640   */
641  takeGas (amount) {
642    if (this.kernel.environment.gasLeft < amount) {
643      throw new Error('Ran out of gas')
644    }
645    this.kernel.environment.gasLeft -= amount
646  }
647}
648
649// converts a 64 bit number to a JS number
650function from64bit (high, low) {
651  if (high < 0) {
652    // convert from a 32-bit two's compliment
653    high = 0x100000000 - high
654  }
655  if (low < 0) {
656    // convert from a 32-bit two's compliment
657    low = 0x100000000 - low
658  }
659  // JS only bitshift 32bits, so instead of high << 32 we have high * 2 ^ 32
660  return (high * 4294967296) + low
661}
662

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