plugeth/core/execution.go
Felix Lange 1f1ea18b54 core/state: implement reverts by journaling all changes
This commit replaces the deep-copy based state revert mechanism with a
linear complexity journal. This commit also hides several internal
StateDB methods to limit the number of ways in which calling code can
use the journal incorrectly.

As usual consultation and bug fixes to the initial implementation were
provided by @karalabe, @obscuren and @Arachnid. Thank you!
2016-10-06 15:32:16 +02:00

176 lines
6.4 KiB
Go

// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package core
import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/params"
)
// Call executes within the given contract
func Call(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice, value *big.Int) (ret []byte, err error) {
ret, _, err = exec(env, caller, &addr, &addr, env.Db().GetCodeHash(addr), input, env.Db().GetCode(addr), gas, gasPrice, value)
return ret, err
}
// CallCode executes the given address' code as the given contract address
func CallCode(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice, value *big.Int) (ret []byte, err error) {
callerAddr := caller.Address()
ret, _, err = exec(env, caller, &callerAddr, &addr, env.Db().GetCodeHash(addr), input, env.Db().GetCode(addr), gas, gasPrice, value)
return ret, err
}
// DelegateCall is equivalent to CallCode except that sender and value propagates from parent scope to child scope
func DelegateCall(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice *big.Int) (ret []byte, err error) {
callerAddr := caller.Address()
originAddr := env.Origin()
callerValue := caller.Value()
ret, _, err = execDelegateCall(env, caller, &originAddr, &callerAddr, &addr, env.Db().GetCodeHash(addr), input, env.Db().GetCode(addr), gas, gasPrice, callerValue)
return ret, err
}
// Create creates a new contract with the given code
func Create(env vm.Environment, caller vm.ContractRef, code []byte, gas, gasPrice, value *big.Int) (ret []byte, address common.Address, err error) {
ret, address, err = exec(env, caller, nil, nil, crypto.Keccak256Hash(code), nil, code, gas, gasPrice, value)
// Here we get an error if we run into maximum stack depth,
// See: https://github.com/ethereum/yellowpaper/pull/131
// and YP definitions for CREATE instruction
if err != nil {
return nil, address, err
}
return ret, address, err
}
func exec(env vm.Environment, caller vm.ContractRef, address, codeAddr *common.Address, codeHash common.Hash, input, code []byte, gas, gasPrice, value *big.Int) (ret []byte, addr common.Address, err error) {
evm := env.Vm()
// Depth check execution. Fail if we're trying to execute above the
// limit.
if env.Depth() > int(params.CallCreateDepth.Int64()) {
caller.ReturnGas(gas, gasPrice)
return nil, common.Address{}, vm.DepthError
}
if !env.CanTransfer(caller.Address(), value) {
caller.ReturnGas(gas, gasPrice)
return nil, common.Address{}, ValueTransferErr("insufficient funds to transfer value. Req %v, has %v", value, env.Db().GetBalance(caller.Address()))
}
var createAccount bool
if address == nil {
// Create a new account on the state
nonce := env.Db().GetNonce(caller.Address())
env.Db().SetNonce(caller.Address(), nonce+1)
addr = crypto.CreateAddress(caller.Address(), nonce)
address = &addr
createAccount = true
}
snapshotPreTransfer := env.SnapshotDatabase()
var (
from = env.Db().GetAccount(caller.Address())
to vm.Account
)
if createAccount {
to = env.Db().CreateAccount(*address)
} else {
if !env.Db().Exist(*address) {
to = env.Db().CreateAccount(*address)
} else {
to = env.Db().GetAccount(*address)
}
}
env.Transfer(from, to, value)
// initialise a new contract and set the code that is to be used by the
// EVM. The contract is a scoped environment for this execution context
// only.
contract := vm.NewContract(caller, to, value, gas, gasPrice)
contract.SetCallCode(codeAddr, codeHash, code)
defer contract.Finalise()
ret, err = evm.Run(contract, input)
// if the contract creation ran successfully and no errors were returned
// calculate the gas required to store the code. If the code could not
// be stored due to not enough gas set an error and let it be handled
// by the error checking condition below.
if err == nil && createAccount {
dataGas := big.NewInt(int64(len(ret)))
dataGas.Mul(dataGas, params.CreateDataGas)
if contract.UseGas(dataGas) {
env.Db().SetCode(*address, ret)
} else {
err = vm.CodeStoreOutOfGasError
}
}
// When an error was returned by the EVM or when setting the creation code
// above we revert to the snapshot and consume any gas remaining. Additionally
// when we're in homestead this also counts for code storage gas errors.
if err != nil && (env.RuleSet().IsHomestead(env.BlockNumber()) || err != vm.CodeStoreOutOfGasError) {
contract.UseGas(contract.Gas)
env.RevertToSnapshot(snapshotPreTransfer)
}
return ret, addr, err
}
func execDelegateCall(env vm.Environment, caller vm.ContractRef, originAddr, toAddr, codeAddr *common.Address, codeHash common.Hash, input, code []byte, gas, gasPrice, value *big.Int) (ret []byte, addr common.Address, err error) {
evm := env.Vm()
// Depth check execution. Fail if we're trying to execute above the
// limit.
if env.Depth() > int(params.CallCreateDepth.Int64()) {
caller.ReturnGas(gas, gasPrice)
return nil, common.Address{}, vm.DepthError
}
snapshot := env.SnapshotDatabase()
var to vm.Account
if !env.Db().Exist(*toAddr) {
to = env.Db().CreateAccount(*toAddr)
} else {
to = env.Db().GetAccount(*toAddr)
}
// Iinitialise a new contract and make initialise the delegate values
contract := vm.NewContract(caller, to, value, gas, gasPrice).AsDelegate()
contract.SetCallCode(codeAddr, codeHash, code)
defer contract.Finalise()
ret, err = evm.Run(contract, input)
if err != nil {
contract.UseGas(contract.Gas)
env.RevertToSnapshot(snapshot)
}
return ret, addr, err
}
// generic transfer method
func Transfer(from, to vm.Account, amount *big.Int) {
from.SubBalance(amount)
to.AddBalance(amount)
}