path: root/accounts/account_manager.go

/*
    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 (
    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")
)

// TODO: better name for this struct?
type Account struct {
    Address []byte
}

type AccountManager struct {
    keyStore           crypto.KeyStore2
    unlockedKeys       map[string]crypto.Key
    unlockMilliseconds time.Duration
    mutex              sync.RWMutex
}

func NewAccountManager(keyStore crypto.KeyStore2, unlockMilliseconds time.Duration) *AccountManager {
    return &AccountManager{
        keyStore:           keyStore,
        unlockedKeys:       make(map[string]crypto.Key),
        unlockMilliseconds: unlockMilliseconds,
    }
}

// Coinbase returns the account address that mining rewards are sent to.
func (am *AccountManager) Coinbase() (addr []byte, err error) {
    // TODO: persist coinbase address on disk
    return am.firstAddr()
}

// MainAccount returns the primary account used for transactions.
func (am *AccountManager) Default() (*Account, error) {
    // TODO: persist main account address on disk
    addr, err := am.firstAddr()
    return &Account{Address: addr}, err
}

func (am *AccountManager) 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 *AccountManager) DeleteAccount(address []byte, auth string) error {
    return am.keyStore.DeleteKey(address, auth)
}

func (am *AccountManager) Sign(fromAccount *Account, toSign []byte) (signature []byte, err error) {
    am.mutex.RLock()
    unlockedKey := am.unlockedKeys[string(fromAccount.Address)]
    am.mutex.RUnlock()
    if unlockedKey.Address == nil {
        return nil, ErrLocked
    }
    signature, err = crypto.Sign(toSign, unlockedKey.PrivateKey)
    return signature, err
}

func (am *AccountManager) SignLocked(fromAccount *Account, keyAuth string, toSign []byte) (signature []byte, err error) {
    key, err := am.keyStore.GetKey(fromAccount.Address, keyAuth)
    if err != nil {
        return nil, err
    }
    am.mutex.RLock()
    am.unlockedKeys[string(fromAccount.Address)] = *key
    am.mutex.RUnlock()
    go unlockLater(am, fromAccount.Address)
    signature, err = crypto.Sign(toSign, key.PrivateKey)
    return signature, err
}

func (am AccountManager) NewAccount(auth string) (*Account, error) {
    key, err := am.keyStore.GenerateNewKey(crand.Reader, auth)
    if err != nil {
        return nil, err
    }
    ua := &Account{
        Address: key.Address,
    }
    return ua, err
}

func (am *AccountManager) 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 unlockLater(am *AccountManager, addr []byte) {
    select {
    case <-time.After(time.Millisecond * am.unlockMilliseconds):
    }
    am.mutex.RLock()
    // TODO: how do we know the key is actually gone from memory?
    delete(am.unlockedKeys, string(addr))
    am.mutex.RUnlock()
}