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// Copyright 2015 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 versions
import (
"fmt"
"math/big"
"strconv"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/eth"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
)
var (
jsonlogger = logger.NewJsonLogger()
// TODO: add Frontier address
GlobalVersionsAddr = common.HexToAddress("0x40bebcadbb4456db23fda39f261f3b2509096e9e") // test
dummySender = common.HexToAddress("0x16db48070243bc37a1c59cd5bb977ad7047618be") // test
getVersionsSignature = "GetVersions()"
firstCheckTime = time.Second * 4
continousCheckTime = time.Second * 600
)
type VersionCheck struct {
serverName string
timer *time.Timer
e *eth.Ethereum
stop chan bool
}
// Boilerplate to satisfy node.Service interface
func (v *VersionCheck) Protocols() []p2p.Protocol {
return []p2p.Protocol{}
}
func (v *VersionCheck) APIs() []rpc.API {
return []rpc.API{}
}
func (v *VersionCheck) Start(server *p2p.Server) error {
v.serverName = server.Name
// Check version first time after a few seconds so it shows after
// other startup messages
t := time.NewTimer(firstCheckTime)
v.timer = t
v.stop = make(chan bool)
versionCheck := func() {
for {
select {
case <-v.stop:
close(v.stop)
return
case <-v.timer.C:
_, err := get(v.e, v.serverName)
if err != nil {
glog.V(logger.Error).Infof("Could not query geth version contract: %s", err)
}
v.timer.Reset(continousCheckTime)
}
}
}
go versionCheck()
return nil
}
func (v *VersionCheck) Stop() error {
v.stop <- true
select {
case <-v.stop:
}
return nil
}
func NewVersionCheck(ctx *node.ServiceContext) (node.Service, error) {
var v VersionCheck
var e *eth.Ethereum
// sets e to the Ethereum instance previously started
// expects double pointer
ctx.Service(&e)
v.e = e
return &v, nil
}
// query versions list from the (custom) accessor in the versions contract
func get(e *eth.Ethereum, clientVersion string) (string, error) {
// TODO: move common/registrar abiSignature to some util package
abi := crypto.Sha3([]byte(getVersionsSignature))[:4]
res, _, err := simulateCall(
e,
&dummySender,
&GlobalVersionsAddr,
big.NewInt(3000000), // gasLimit
big.NewInt(1), // gasPrice
big.NewInt(0), // value
abi)
if err != nil {
return "", err
}
// TODO: we use static arrays of size versionCount as workaround
// until solidity has proper support for returning dynamic arrays
versionCount := 10
if len(res) != 2+(64*versionCount*3) { // 0x + three 32-byte fields per version
return "", fmt.Errorf("unexpected result length from GetVersions")
}
// TODO: use ABI (after solidity supports returning arrays of arrays and/or structs)
var versions []string
var timestamps []uint64
var signerCounts []uint64
// trim 0x
res = res[2:]
// parse res
for i := 0; i < versionCount; i++ {
bytes := common.FromHex(res[:64])
versions = append(versions, string(bytes))
res = res[64:]
}
for i := 0; i < versionCount; i++ {
ts, err := strconv.ParseUint(res[:64], 16, 64)
if err != nil {
return "", err
}
timestamps = append(timestamps, ts)
res = res[64:]
}
for i := 0; i < versionCount; i++ {
sc, err := strconv.ParseUint(res[:64], 16, 64)
if err != nil {
return "", err
}
signerCounts = append(signerCounts, sc)
res = res[64:]
}
// TODO: version matching logic (e.g. most votes / most recent)
if versions[0] != clientVersion {
glog.V(logger.Info).Infof("geth version %s does not match recommended version %s", clientVersion, versions[0])
}
return res, nil
}
func simulateCall(e *eth.Ethereum, from0, to *common.Address, gas, gasPrice, value *big.Int, data []byte) (string, *big.Int, error) {
stateCopy, err := e.BlockChain().State()
if err != nil {
return "", nil, err
}
from := stateCopy.GetOrNewStateObject(*from0)
from.SetBalance(common.MaxBig)
msg := callmsg{
from: from,
to: to,
gas: gas,
gasPrice: gasPrice,
value: value,
data: data,
}
// Execute the call and return
vmenv := core.NewEnv(stateCopy, e.BlockChain(), msg, e.BlockChain().CurrentHeader())
gp := new(core.GasPool).AddGas(common.MaxBig)
res, gas, err := core.ApplyMessage(vmenv, msg, gp)
return common.ToHex(res), gas, err
}
// TODO: consider moving to package common or accounts/abi as it's useful for anyone
// simulating EVM CALL
type callmsg struct {
from *state.StateObject
to *common.Address
gas, gasPrice *big.Int
value *big.Int
data []byte
}
// accessor boilerplate to implement core.Message
func (m callmsg) From() (common.Address, error) { return m.from.Address(), nil }
func (m callmsg) Nonce() uint64 { return m.from.Nonce() }
func (m callmsg) To() *common.Address { return m.to }
func (m callmsg) GasPrice() *big.Int { return m.gasPrice }
func (m callmsg) Gas() *big.Int { return m.gas }
func (m callmsg) Value() *big.Int { return m.value }
func (m callmsg) Data() []byte { return m.data }
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