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wanderer🌟 / js-primea-hypervisor



Tree: a3b9c88c4884b2b2f42a88e75023168e5f85a08a

Files: a3b9c88c4884b2b2f42a88e75023168e5f85a08a / 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 constants = require('./constants.js')
6const Address = require('./address.js')
7const U256 = require('./u256.js')
8
9// The interface exposed to the WebAessembly Core
10module.exports = class Interface {
11  constructor (environment) {
12    this.environment = environment
13  }
14
15  get exportTable () {
16    let exportMethods = [
17      // include all the public methods according to the Ethereum Environment Interface (EEI) r1
18      'useGas',
19      'getGasLeft',
20      'getAddress',
21      'getBalance',
22      'getTxOrigin',
23      'getCaller',
24      'getCallValue',
25      'getCallDataSize',
26      'callDataCopy',
27      'callDataCopy256',
28      'getCodeSize',
29      'codeCopy',
30      'getExternalCodeSize',
31      'externalCodeCopy',
32      'getTxGasPrice',
33      'getBlockHash',
34      'getBlockCoinbase',
35      'getBlockTimestamp',
36      'getBlockNumber',
37      'getBlockDifficulty',
38      'getBlockGasLimit',
39      'log',
40      'create',
41      'call',
42      'callCode',
43      'callDelegate',
44      'storageStore',
45      'storageLoad',
46      'return',
47      'selfDestruct'
48    ]
49    let ret = {}
50    exportMethods.forEach((method) => {
51      ret[method] = this[method].bind(this)
52    })
53    return ret
54  }
55
56  setModule (mod) {
57    this.module = mod
58  }
59
60  /**
61   * Subtracts an amount to the gas counter
62   * @param {integer} amount the amount to subtract to the gas counter
63   */
64  useGas (amount) {
65    if (amount < 0) {
66      throw new Error('Negative gas deduction requested')
67    }
68
69    this.takeGas(amount)
70  }
71
72  /**
73   * Returns the current amount of gas
74   * @return {integer}
75   */
76  getGasLeft () {
77    this.takeGas(2)
78
79    return this.environment.gasLeft
80  }
81
82  /**
83   * Gets address of currently executing account and loads it into memory at
84   * the given offset.
85   * @param {integer} offset
86   */
87  getAddress (offset) {
88    this.takeGas(2)
89
90    this.setMemory(offset, constants.ADDRESS_SIZE_BYTES, this.environment.address)
91  }
92
93  /**
94   * Gets balance of the given account and loads it into memory at the given
95   * offset.
96   * @param {integer} addressOffset the memory offset to laod the address
97   * @param {integer} resultOffset
98   */
99  getBalance (addressOffset, offset) {
100    this.takeGas(20)
101
102    const address = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
103    // call the parent contract and ask for the balance of one of its child contracts
104    const balance = this.environment.parent.environment.getBalance(address)
105    this.setMemory(offset, constants.BALANCE_SIZE_BYTES, balance.toBuffer(constants.BALANCE_SIZE_BYTES))
106  }
107
108  /**
109   * Gets the execution's origination address and loads it into memory at the
110   * given offset. This is the sender of original transaction; it is never an
111   * account with non-empty associated code.
112   * @param {integer} offset
113   */
114  getTxOrigin (offset) {
115    this.takeGas(2)
116
117    this.setMemory(offset, constants.ADDRESS_SIZE_BYTES, this.environment.origin)
118  }
119
120  /**
121   * Gets caller address and loads it into memory at the given offset. This is
122   * the address of the account that is directly responsible for this execution.
123   * @param {integer} offset
124   */
125  getCaller (offset) {
126    this.takeGas(2)
127
128    this.setMemory(offset, constants.ADDRESS_SIZE_BYTES, this.environment.caller)
129  }
130
131  /**
132   * Gets the deposited value by the instruction/transaction responsible for
133   * this execution and loads it into memory at the given location.
134   * @param {integer} offset
135   */
136  getCallValue (offset) {
137    this.takeGas(2)
138
139    this.setMemory(offset, constants.BALANCE_SIZE_BYTES, this.environment.callValue.toBuffer(constants.BALANCE_SIZE_BYTES))
140  }
141
142  /**
143   * Get size of input data in current environment. This pertains to the input
144   * data passed with the message call instruction or transaction.
145   * @return {integer}
146   */
147  getCallDataSize () {
148    this.takeGas(2)
149
150    return this.environment.callData.length
151  }
152
153  /**
154   * Copys the input data in current environment to memory. This pertains to
155   * the input data passed with the message call instruction or transaction.
156   * @param {integer} offset the offset in memory to load into
157   * @param {integer} dataOffset the offset in the input data
158   * @param {integer} length the length of data to copy
159   */
160  callDataCopy (offset, dataOffset, length) {
161    this.takeGas(3 + ((length / 32) * 3))
162
163    const callData = this.environment.callData.slice(dataOffset, dataOffset + length)
164    this.setMemory(offset, length, callData)
165  }
166
167  /**
168   * Copys the input data in current environment to memory. This pertains to
169   * the input data passed with the message call instruction or transaction.
170   * @param {integer} offset the offset in memory to load into
171   * @param {integer} dataOffset the offset in the input data
172   * @param {integer} length the length of data to copy
173   */
174  callDataCopy256 (offset, dataOffset) {
175    this.takeGas(3)
176    const callData = this.environment.callData.slice(dataOffset, dataOffset + 32)
177    this.setMemory(offset, 32, callData)
178  }
179
180  /**
181   * Gets the size of code running in current environment.
182   * @return {interger}
183   */
184  getCodeSize () {
185    this.takeGas(2)
186
187    return this.environment.code.length
188  }
189
190  /**
191   * Copys the code running in current environment to memory.
192   * @param {integer} offset the memory offset
193   * @param {integer} codeOffset the code offset
194   * @param {integer} length the length of code to copy
195   */
196  codeCopy (resultOffset, codeOffset, length) {
197    this.takeGas(3 + ((length / 32) * 3))
198
199    const code = new Uint8Array(this.environment.code, codeOffset, length)
200    this.setMemory(resultOffset, length, code)
201  }
202
203  /**
204   * Get size of an account’s code.
205   * @param {integer} addressOffset the offset in memory to load the address from
206   * @return {integer}
207   */
208  getExternalCodeSize (addressOffset) {
209    this.takeGas(20)
210
211    const address = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
212    const code = this.environment.getCode(address)
213    return code.length
214  }
215
216  /**
217   * Copys the code of an account to memory.
218   * @param {integer} addressOffset the memory offset of the address
219   * @param {integer} resultOffset the memory offset
220   * @param {integer} codeOffset the code offset
221   * @param {integer} length the length of code to copy
222   */
223  externalCodeCopy (addressOffset, resultOffset, codeOffset, length) {
224    this.takeGas(20 + ((length / 32) * 3))
225
226    const address = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
227    let code = this.environment.getCode(address)
228    code = new Uint8Array(code, codeOffset, length)
229    this.setMemory(resultOffset, length, code)
230  }
231
232  /**
233   * Gets price of gas in current environment.
234   * @return {integer}
235   */
236  getTxGasPrice () {
237    this.takeGas(2)
238
239    return this.environment.gasPrice
240  }
241
242  /**
243   * Gets the hash of one of the 256 most recent complete blocks.
244   * @param {integer} number which block to load
245   * @param {integer} offset the offset to load the hash into
246   */
247  getBlockHash (number, offset) {
248    this.takeGas(20)
249
250    const diff = this.environment.block.number - number
251    let hash
252
253    if (diff > 256 || diff <= 0) {
254      hash = new U256(0)
255    } else {
256      hash = new U256(this.environment.getBlockHash(number))
257    }
258    this.setMemory(offset, 32, hash.toBuffer())
259  }
260
261  /**
262   * Gets the block’s beneficiary address and loads into memory.
263   * @param offset
264   */
265  getBlockCoinbase (offset) {
266    this.takeGas(2)
267
268    this.setMemory(offset, constants.ADDRESS_SIZE_BYTES, this.environment.block.coinbase)
269  }
270
271  /**
272   * Get the block’s timestamp.
273   * @return {integer}
274   */
275  getBlockTimestamp () {
276    this.takeGas(2)
277
278    return this.environment.block.timestamp
279  }
280
281  /**
282   * Get the block’s number.
283   * @return {integer}
284   */
285  getBlockNumber () {
286    this.takeGas(2)
287
288    return this.environment.block.number
289  }
290
291  /**
292   * Get the block’s difficulty.
293   * @return {integer}
294   */
295  getBlockDifficulty (offset) {
296    this.takeGas(2)
297
298    this.setMemory(offset, 32, this.environment.block.difficulty.toBuffer())
299  }
300
301  /**
302   * Get the block’s gas limit.
303   * @return {integer}
304   */
305  getBlockGasLimit () {
306    this.takeGas(2)
307
308    return this.environment.block.gasLimit
309  }
310
311  /**
312   * Creates a new log in the current environment
313   * @param {integer} dataOffset the offset in memory to load the memory
314   * @param {integer} length the data length
315   * TODO: replace with variadic
316   */
317  log (dataOffset, length, topic1, topic2, topic3, topic4, topic5) {
318    // FIXME: calculate gas for topics set
319    this.takeGas(375 + length * 8)
320
321    const data = this.getMemory(dataOffset, length)
322    this.environment.logs.push({
323      data: data,
324      topics: [topic1, topic2, topic3, topic4, topic5]
325    })
326  }
327
328  /**
329   * Creates a new contract with a given value.
330   * @param {integer} valueOffset the offset in memory to the value from
331   * @param {integer} dataOffset the offset to load the code for the new contract from
332   * @param {integer} length the data length
333   */
334  create (valueOffset, dataOffset, length) {
335    this.takeGas(32000)
336
337    const value = new U256(this.getMemory(valueOffset, constants.BALANCE_SIZE_BYTES))
338    const data = this.getMemory(dataOffset, length)
339    const result = this.environment.create(value, data)
340    return result
341  }
342
343  /**
344   * Sends a message with arbiatary data to a given address path
345   * @param {integer} addressOffset the offset to load the address path from
346   * @param {integer} valueOffset the offset to load the value from
347   * @param {integer} dataOffset the offset to load data from
348   * @param {integer} dataLength the length of data
349   * @param {integer} resultOffset the offset to store the result data at
350   * @param {integer} resultLength
351   * @param {integer} gas
352   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
353   */
354  call (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
355    // FIXME: count properly
356    this.takeGas(40)
357
358    if (gas === undefined) {
359      gas = this.gasLeft()
360    }
361    // Load the params from mem
362    const address = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
363    const value = new U256(this.getMemory(valueOffset, constants.BALANCE_SIZE_BYTES))
364    const data = this.getMemory(dataOffset, dataLength)
365    // Run the call
366    const [result, errorCode] = this.environment.call(gas, address, value, data)
367    this.setMemory(resultOffset, resultLength, result)
368    return errorCode
369  }
370
371  /**
372   * Message-call into this account with an alternative account’s code.
373   * @param {integer} addressOffset the offset to load the address path from
374   * @param {integer} valueOffset the offset to load the value from
375   * @param {integer} dataOffset the offset to load data from
376   * @param {integer} dataLength the length of data
377   * @param {integer} resultOffset the offset to store the result data at
378   * @param {integer} resultLength
379   * @param {integer} gas
380   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
381   */
382  callCode (gas, addressOffset, valueOffset, dataOffset, dataLength, resultOffset, resultLength) {
383    // FIXME: count properly
384    this.takeGas(40)
385
386    // Load the params from mem
387    const address = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
388    const value = new U256(this.getMemory(valueOffset, constants.BALANCE_SIZE_BYTES))
389    const data = this.getMemory(dataOffset, dataLength)
390    // Run the call
391    const [result, errorCode] = this.environment.callCode(gas, address, value, data)
392    this.setMemory(resultOffset, resultLength, result)
393    return errorCode
394  }
395
396  /**
397   * Message-call into this account with an alternative account’s code, but
398   * persisting the current values for sender and value.
399   * @param {integer} gas
400   * @param {integer} addressOffset the offset to load the address path from
401   * @param {integer} valueOffset the offset to load the value from
402   * @param {integer} dataOffset the offset to load data from
403   * @param {integer} dataLength the length of data
404   * @param {integer} resultOffset the offset to store the result data at
405   * @param {integer} resultLength
406   * @return {integer} Returns 1 or 0 depending on if the VM trapped on the message or not
407   */
408  callDelegate (gas, addressOffset, dataOffset, dataLength, resultOffset, resultLength) {
409    // FIXME: count properly
410    this.takeGas(40)
411
412    const data = this.getMemory(dataOffset, dataLength)
413    const address = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
414    const [result, errorCode] = this.environment.callDelegate(gas, address, data)
415    this.setMemory(resultOffset, resultLength, result)
416    return errorCode
417  }
418
419  /**
420   * store a value at a given path in long term storage which are both loaded
421   * from Memory
422   * @param {interger} pathOffest the memory offset to load the the path from
423   * @param {interger} valueOffset the memory offset to load the value from
424   */
425  storageStore (pathOffset, valueOffset) {
426    const path = new Buffer(this.getMemory(pathOffset, 32)).toString('hex')
427    // copy the value
428    const value = this.getMemory(valueOffset, 32).slice(0)
429    const oldValue = this.environment.state.get(path)
430    const valIsZero = value.every((i) => i === 0)
431
432    this.takeGas(5000)
433
434    // write
435    if (!valIsZero && !oldValue) {
436      this.takeGas(15000)
437    }
438
439    // delete
440    if (valIsZero && oldValue) {
441      this.environment.gasRefund += 15000
442      this.environment.state.delete(path)
443    } else {
444      this.environment.state.set(path, value)
445    }
446  }
447
448  /**
449   * reterives a value at a given path in long term storage
450   * @param {interger} pathOffest the memory offset to load the the path from
451   * @param {interger} resultOffset the memory offset to load the value from
452   */
453  storageLoad (pathOffset, resultOffset) {
454    this.takeGas(50)
455
456    const path = new Buffer(this.getMemory(pathOffset, 32)).toString('hex')
457    const result = this.environment.state.get(path)
458    this.setMemory(resultOffset, 32, result)
459  }
460
461  /**
462   * Halt execution returning output data.
463   * @param {integer} offset the offset of the output data.
464   * @param {integer} length the length of the output data.
465   */
466  return (offset, length) {
467    this.environment.returnValue = this.getMemory(offset, length)
468  }
469
470  /**
471   * Halt execution and register account for later deletion giving the remaining
472   * balance to an address path
473   * @param {integer} offset the offset to load the address from
474   */
475  selfDestruct (addressOffset) {
476    this.environment.suicideAddress = new Address(this.getMemory(addressOffset, constants.ADDRESS_SIZE_BYTES))
477    this.environment.gasRefund += 24000
478  }
479
480  getMemory (offset, length) {
481    return new Uint8Array(this.module.exports.memory, offset, length)
482  }
483
484  setMemory (offset, length, value) {
485    const memory = new Uint8Array(this.module.exports.memory, offset, length)
486    memory.set(value)
487  }
488
489  /*
490   * Takes gas from the tank. Only needs to check if there's gas left to be taken,
491   * because every caller of this method is trusted.
492   */
493  takeGas (amount) {
494    if (this.environment.gasLeft < amount) {
495      throw new Error('Ran out of gas')
496    }
497    this.environment.gasLeft -= amount
498  }
499}
500
501//
502// Polyfill required unless this is sorted: https://bugs.chromium.org/p/chromium/issues/detail?id=633895
503//
504// Polyfill from: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_objects/Function/bind
505//
506Function.prototype.bind = function (oThis) { // eslint-disable-line
507  if (typeof this !== 'function') {
508    // closest thing possible to the ECMAScript 5
509    // internal IsCallable function
510    throw new TypeError('Function.prototype.bind - what is trying to be bound is not callable')
511  }
512
513  var aArgs = Array.prototype.slice.call(arguments, 1)
514  var fToBind = this
515  var fNOP = function () {}
516  var fBound = function () {
517    return fToBind.apply(this instanceof fNOP ? this : oThis,
518     aArgs.concat(Array.prototype.slice.call(arguments)))
519  }
520
521  if (this.prototype) {
522    // Function.prototype doesn't have a prototype property
523    fNOP.prototype = this.prototype
524  }
525
526  fBound.prototype = new fNOP() // eslint-disable-line new-cap
527
528  return fBound
529}
530

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