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/*
This file is part of go-ethereum
go-ethereum 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.
go-ethereum 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 General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @authors
* Gustav Simonsson <gustav.simonsson@gmail.com>
* @date 2015
*
*/
/*
This abstracts part of a user's interaction with an account she controls.
It's not an abstraction of core Ethereum accounts data type / logic -
for that see the core processing code of blocks / txs.
Currently this is pretty much a passthrough to the KeyStore2 interface,
and accounts persistence is derived from stored keys' addresses
*/
package accounts
import (
"crypto/ecdsa"
crand "crypto/rand"
"errors"
"sync"
"time"
"github.com/ethereum/go-ethereum/crypto"
)
var (
ErrLocked = errors.New("account is locked")
ErrNoKeys = errors.New("no keys in store")
)
type Account struct {
Address []byte
}
type Manager struct {
keyStore crypto.KeyStore2
unlocked map[string]*unlocked
unlockTime time.Duration
mutex sync.RWMutex
}
type unlocked struct {
*crypto.Key
abort chan struct{}
}
func NewManager(keyStore crypto.KeyStore2, unlockTime time.Duration) *Manager {
return &Manager{
keyStore: keyStore,
unlocked: make(map[string]*unlocked),
unlockTime: unlockTime,
}
}
// Coinbase returns the account address that mining rewards are sent to.
func (am *Manager) Coinbase() (addr []byte, err error) {
// TODO: persist coinbase address on disk
return am.firstAddr()
}
// MainAccount returns the primary account used for transactions.
func (am *Manager) Default() (Account, error) {
// TODO: persist main account address on disk
addr, err := am.firstAddr()
return Account{Address: addr}, err
}
func (am *Manager) firstAddr() ([]byte, error) {
addrs, err := am.keyStore.GetKeyAddresses()
if err != nil {
return nil, err
}
if len(addrs) == 0 {
return nil, ErrNoKeys
}
return addrs[0], nil
}
func (am *Manager) DeleteAccount(address []byte, auth string) error {
return am.keyStore.DeleteKey(address, auth)
}
func (am *Manager) Sign(a Account, toSign []byte) (signature []byte, err error) {
am.mutex.RLock()
unlockedKey, found := am.unlocked[string(a.Address)]
am.mutex.RUnlock()
if !found {
return nil, ErrLocked
}
signature, err = crypto.Sign(toSign, unlockedKey.PrivateKey)
return signature, err
}
func (am *Manager) SignLocked(a Account, keyAuth string, toSign []byte) (signature []byte, err error) {
key, err := am.keyStore.GetKey(a.Address, keyAuth)
if err != nil {
return nil, err
}
u := am.addUnlocked(a.Address, key)
go am.dropLater(a.Address, u)
signature, err = crypto.Sign(toSign, key.PrivateKey)
return signature, err
}
func (am *Manager) NewAccount(auth string) (Account, error) {
key, err := am.keyStore.GenerateNewKey(crand.Reader, auth)
if err != nil {
return Account{}, err
}
return Account{Address: key.Address}, nil
}
func (am *Manager) Accounts() ([]Account, error) {
addresses, err := am.keyStore.GetKeyAddresses()
if err != nil {
return nil, err
}
accounts := make([]Account, len(addresses))
for i, addr := range addresses {
accounts[i] = Account{
Address: addr,
}
}
return accounts, err
}
func (am *Manager) addUnlocked(addr []byte, key *crypto.Key) *unlocked {
u := &unlocked{Key: key, abort: make(chan struct{})}
am.mutex.Lock()
prev, found := am.unlocked[string(addr)]
if found {
// terminate dropLater for this key to avoid unexpected drops.
close(prev.abort)
zeroKey(prev.PrivateKey)
}
am.unlocked[string(addr)] = u
am.mutex.Unlock()
return u
}
func (am *Manager) dropLater(addr []byte, u *unlocked) {
t := time.NewTimer(am.unlockTime)
defer t.Stop()
select {
case <-u.abort:
// just quit
case <-t.C:
am.mutex.Lock()
// only drop if it's still the same key instance that dropLater
// was launched with. we can check that using pointer equality
// because the map stores a new pointer every time the key is
// unlocked.
if am.unlocked[string(addr)] == u {
zeroKey(u.PrivateKey)
delete(am.unlocked, string(addr))
}
am.mutex.Unlock()
}
}
// zeroKey zeroes a private key in memory.
func zeroKey(k *ecdsa.PrivateKey) {
b := k.D.Bits()
for i := range b {
b[i] = 0
}
}
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