Files: dbb9b6eacbc6786a69bbe76a01aa4fb1d930ff18 / index.js
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1 | /** |
2 | * This implements the Ethereum Kernel |
3 | * Kernels must implement two methods `codeHandler` and `callHandler` (and `linkHandler` for sharding) |
4 | * The Kernel Contract handles the following |
5 | * - Interprocess communications |
6 | * - Intializing the VM and exposes ROM to it (codeHandler) |
7 | * - Expose namespace which VM instance exists and Intializes the Environment (callHandler) |
8 | * - Provides some built in contract (runTx, runBlock) |
9 | * - Provides resource sharing and limiting via gas |
10 | * |
11 | * All State should be stored in the Environment. |
12 | * |
13 | */ |
14 | |
15 | // The Kernel Exposes this Interface to VM instances it makes |
16 | const Interface = require('./interface.js') |
17 | |
18 | // The Kernel Stores all of its state in the Environment. The Interface is used |
19 | // to by the VM to retrive infromation from the Environment. |
20 | const Environment = require('./environment.js') |
21 | |
22 | const DebugInterface = require('./debugInterface.js') |
23 | |
24 | const Address = require('./address.js') |
25 | const U256 = require('./u256.js') |
26 | const Utils = require('./utils.js') |
27 | |
28 | module.exports = class Kernel { |
29 | // runs some code in the VM |
30 | constructor (environment = new Environment()) { |
31 | this.environment = environment |
32 | } |
33 | |
34 | // handles running code. |
35 | // NOTE: it assumes that wasm will raise an exception if something went wrong, |
36 | // otherwise execution succeeded |
37 | codeHandler (code, ethInterface = new Interface(new Environment())) { |
38 | const debugInterface = new DebugInterface(ethInterface.environment) |
39 | |
40 | const instance = Wasm.instantiateModule(code, { |
41 | 'ethereum': ethInterface.exportTable, |
42 | 'debug': debugInterface.exportTable, |
43 | |
44 | // export this for Rust |
45 | // FIXME: remove once Rust has proper imports, see https://github.com/ethereum/evm2.0-design/issues/15 |
46 | 'spectest': ethInterface.exportTable, |
47 | |
48 | // export this for Binaryen |
49 | // FIXME: remove once C has proper imports, see https://github.com/ethereum/evm2.0-design/issues/16 |
50 | 'env': ethInterface.exportTable |
51 | }) |
52 | |
53 | ethInterface.setModule(instance) |
54 | debugInterface.setModule(instance) |
55 | |
56 | if (instance.exports.main) { |
57 | instance.exports.main() |
58 | } |
59 | return instance |
60 | } |
61 | |
62 | // loads code from the merkle trie and delegates the message |
63 | // Detects if code is EVM or WASM |
64 | // Detects if the code injection is needed |
65 | // Detects if transcompilation is needed |
66 | callHandler (address, gaslimit, gasprice, value, data) { |
67 | // Special case: contract deployment |
68 | // FIXME: place this in the best location with the best condition checking |
69 | if (address.isZero()) { |
70 | if (data.length !== 0) { |
71 | let codeHash = sha3(data) |
72 | this.environment.state.set(codeHash, data); |
73 | this.environment.state.set(address.toString(), { balance: value, codeHash: codeHash }) |
74 | } |
75 | } |
76 | |
77 | let account = this.environment.state.get(address.toString()) |
78 | if (!account) { |
79 | throw new Error('Account not found') |
80 | } |
81 | |
82 | const code = this.environment.state.get(account.codeHash) |
83 | |
84 | if (!code) { |
85 | throw new Error('Contract not found') |
86 | } |
87 | |
88 | if (!Utils.isWASMCode(code)) { |
89 | throw new Error('Not an eWASM contract') |
90 | } |
91 | |
92 | // creats a new Kernel |
93 | const environment = new Environment(data) |
94 | environment.parent = this |
95 | |
96 | //environment.setCallHandler(callHandler) |
97 | |
98 | const kernel = new Kernel(this, environment) |
99 | kernel.codeHandler(code, new Interface(environment)) |
100 | |
101 | // generate new stateroot |
102 | //this.environment.state.set(address, { stateRoot: stateRoot }) |
103 | |
104 | return { |
105 | executionOutcome: 1, // success |
106 | gasLeft: new U256(environment.gasLimit), // this starts as the limit and results as the gas left |
107 | gasRefund: new U256(environment.gasRefund), |
108 | returnValue: environment.returnValue, |
109 | selfDestructAddress: environment.selfDestructAddress, |
110 | logs: environment.logs |
111 | } |
112 | } |
113 | |
114 | // run tx; the tx message handler |
115 | runTx (tx, environment = new Environment()) { |
116 | // verify tx then send to call Handler |
117 | // - from account has enough balance |
118 | // - check nonce |
119 | // - ecrecover |
120 | // new ethTx(tx).validate(tx) |
121 | // - reduce balance |
122 | |
123 | this.environment = environment |
124 | |
125 | // |
126 | // environment.state - the merkle tree |
127 | // key: address (20 byte, hex string, without 0x prefix) |
128 | // every path has an account |
129 | // |
130 | // { balance, codeHash, stateRoot } |
131 | // |
132 | |
133 | // look up sender |
134 | let fromAccount = this.environment.state.get(tx.from.toString()) |
135 | if (!fromAccount) { |
136 | throw new Error('Sender account not found') |
137 | } |
138 | |
139 | // deduct gasLimit * gasPrice from sender |
140 | if (fromAccount.balance.lt(tx.gasLimit.mul(tx.gasPrice))) { |
141 | throw new Error('Insufficient account balance') |
142 | } |
143 | |
144 | fromAccount.balance = fromAccount.balance.sub(ts.gasLimit.mul(tx.gasPrice)) |
145 | |
146 | let ret = this.callHandler(tx.to, tx.gasLimit, tx.gasPrice, tx.value, tx.data) |
147 | |
148 | // refund gas |
149 | if (ret.executionOutcome === 1) { |
150 | fromAccount.balance = fromAccount.balance.add(tx.gasPrice.mul(ret.gasLeft.add(ret.gasRefund))) |
151 | } |
152 | |
153 | // save new state? |
154 | |
155 | return { |
156 | returnValue: ret.returnValue, |
157 | gasLeft: ret.gasLeft, |
158 | logs: ret.logs |
159 | } |
160 | } |
161 | |
162 | // run block; the block message handler |
163 | runBlock (block, environment = new Environment()) { |
164 | // verify block then run each tx |
165 | block.tx.forEach((tx) => { |
166 | this.runTx(tx, environment) |
167 | }) |
168 | } |
169 | |
170 | // run blockchain |
171 | // runBlockchain () {} |
172 | } |
173 |
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