c12f4df910
Reworked the EVM gas instructions to use 64bit integers rather than arbitrary size big ints. All gas operations, be it additions, multiplications or divisions, are checked and guarded against 64 bit integer overflows. In additon, most of the protocol paramaters in the params package have been converted to uint64 and are now constants rather than variables. * common/math: added overflow check ops * core: vmenv, env renamed to evm * eth, internal/ethapi, les: unmetered eth_call and cancel methods * core/vm: implemented big.Int pool for evm instructions * core/vm: unexported intPool methods & verification methods * core/vm: added memoryGasCost overflow check and test
59 lines
1.9 KiB
Go
59 lines
1.9 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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"math/big"
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"github.com/ethereum/go-ethereum/params"
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)
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const (
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GasQuickStep uint64 = 2
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GasFastestStep uint64 = 3
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GasFastStep uint64 = 5
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GasMidStep uint64 = 8
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GasSlowStep uint64 = 10
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GasExtStep uint64 = 20
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GasReturn uint64 = 0
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GasStop uint64 = 0
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GasContractByte uint64 = 200
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)
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// calcGas returns the actual gas cost of the call.
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//
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// The cost of gas was changed during the homestead price change HF. To allow for EIP150
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// to be implemented. The returned gas is gas - base * 63 / 64.
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func callGas(gasTable params.GasTable, availableGas, base uint64, callCost *big.Int) (uint64, error) {
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if gasTable.CreateBySuicide > 0 {
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availableGas = availableGas - base
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gas := availableGas - availableGas/64
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// If the bit length exceeds 64 bit we know that the newly calculated "gas" for EIP150
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// is smaller than the requested amount. Therefor we return the new gas instead
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// of returning an error.
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if callCost.BitLen() > 64 || gas < callCost.Uint64() {
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return gas, nil
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}
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}
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if callCost.BitLen() > 64 {
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return 0, errGasUintOverflow
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}
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return callCost.Uint64(), nil
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}
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