8b57c49490
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
147 lines
4.2 KiB
Go
147 lines
4.2 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/common"
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)
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// ContractRef is a reference to the contract's backing object
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type ContractRef interface {
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Address() common.Address
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Value() *big.Int
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SetCode(common.Hash, []byte)
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ForEachStorage(callback func(key, value common.Hash) bool)
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}
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// Contract represents an ethereum contract in the state database. It contains
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// the the contract code, calling arguments. Contract implements ContractRef
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type Contract struct {
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// CallerAddress is the result of the caller which initialised this
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// contract. However when the "call method" is delegated this value
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// needs to be initialised to that of the caller's caller.
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CallerAddress common.Address
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caller ContractRef
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self ContractRef
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jumpdests destinations // result of JUMPDEST analysis.
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Code []byte
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CodeHash common.Hash
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CodeAddr *common.Address
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Input []byte
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Gas uint64
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value *big.Int
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Args []byte
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DelegateCall bool
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}
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// NewContract returns a new contract environment for the execution of EVM.
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func NewContract(caller ContractRef, object ContractRef, value *big.Int, gas uint64) *Contract {
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c := &Contract{CallerAddress: caller.Address(), caller: caller, self: object, Args: nil}
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if parent, ok := caller.(*Contract); ok {
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// Reuse JUMPDEST analysis from parent context if available.
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c.jumpdests = parent.jumpdests
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} else {
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c.jumpdests = make(destinations)
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}
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// Gas should be a pointer so it can safely be reduced through the run
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// This pointer will be off the state transition
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c.Gas = gas
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c.value = new(big.Int).Set(value)
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return c
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}
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// AsDelegate sets the contract to be a delegate call and returns the current
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// contract (for chaining calls)
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func (c *Contract) AsDelegate() *Contract {
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c.DelegateCall = true
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// NOTE: caller must, at all times be a contract. It should never happen
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// that caller is something other than a Contract.
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c.CallerAddress = c.caller.(*Contract).CallerAddress
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return c
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}
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// GetOp returns the n'th element in the contract's byte array
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func (c *Contract) GetOp(n uint64) OpCode {
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return OpCode(c.GetByte(n))
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}
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// GetByte returns the n'th byte in the contract's byte array
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func (c *Contract) GetByte(n uint64) byte {
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if n < uint64(len(c.Code)) {
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return c.Code[n]
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}
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return 0
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}
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// Caller returns the caller of the contract.
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//
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// Caller will recursively call caller when the contract is a delegate
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// call, including that of caller's caller.
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func (c *Contract) Caller() common.Address {
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return c.CallerAddress
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}
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// UseGas attempts the use gas and subtracts it and returns true on success
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func (c *Contract) UseGas(gas uint64) (ok bool) {
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if c.Gas < gas {
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return false
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}
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c.Gas -= gas
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return true
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}
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// Address returns the contracts address
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func (c *Contract) Address() common.Address {
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return c.self.Address()
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}
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// Value returns the contracts value (sent to it from it's caller)
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func (c *Contract) Value() *big.Int {
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return c.value
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}
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// SetCode sets the code to the contract
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func (self *Contract) SetCode(hash common.Hash, code []byte) {
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self.Code = code
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self.CodeHash = hash
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}
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// SetCallCode sets the code of the contract and address of the backing data
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// object
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func (self *Contract) SetCallCode(addr *common.Address, hash common.Hash, code []byte) {
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self.Code = code
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self.CodeHash = hash
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self.CodeAddr = addr
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}
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// EachStorage iterates the contract's storage and calls a method for every key
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// value pair.
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func (self *Contract) ForEachStorage(cb func(key, value common.Hash) bool) {
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self.caller.ForEachStorage(cb)
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}
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