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accounts/scwallet: ordered wallets, tighter events, derivation logs

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This commit is contained in:
Péter Szilágyi
2018-04-19 13:39:33 +03:00
committed by Guillaume Ballet
parent 114de0fe2a
commit 386943943f
2 changed files with 82 additions and 64 deletions
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103
accounts/scwallet/hub.go
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@ -36,14 +36,12 @@ import (
"encoding/json"
"io/ioutil"
"os"
"reflect"
"sync"
"time"
"github.com/ebfe/scard"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
)
@ -71,9 +69,10 @@ type smartcardPairing struct {
type Hub struct {
scheme string // Protocol scheme prefixing account and wallet URLs.
context *scard.Context
datadir string
pairings map[string]smartcardPairing
context *scard.Context
datadir string
pairings map[string]smartcardPairing
refreshed time.Time // Time instance when the list of wallets was last refreshed
wallets map[string]*Wallet // Mapping from reader names to wallet instances
updateFeed event.Feed // Event feed to notify wallet additions/removals
@ -82,11 +81,9 @@ type Hub struct {
quit chan chan error
stateLock sync.Mutex // Protects the internals of the hub from racey access
stateLock sync.RWMutex // Protects the internals of the hub from racey access
}
var HubType = reflect.TypeOf(&Hub{})
func (hub *Hub) readPairings() error {
hub.pairings = make(map[string]smartcardPairing)
pairingFile, err := os.Open(hub.datadir + "/smartcards.json")
@ -158,7 +155,6 @@ func NewHub(scheme string, datadir string) (*Hub, error) {
if err != nil {
return nil, err
}
hub := &Hub{
scheme: scheme,
context: context,
@ -166,28 +162,31 @@ func NewHub(scheme string, datadir string) (*Hub, error) {
wallets: make(map[string]*Wallet),
quit: make(chan chan error),
}
if err := hub.readPairings(); err != nil {
return nil, err
}
hub.refreshWallets()
return hub, nil
}
// Wallets implements accounts.Backend, returning all the currently tracked
// devices that appear to be hardware wallets.
// Wallets implements accounts.Backend, returning all the currently tracked smart
// cards that appear to be hardware wallets.
func (hub *Hub) Wallets() []accounts.Wallet {
// Make sure the list of wallets is up to date
hub.stateLock.Lock()
defer hub.stateLock.Unlock()
hub.refreshWallets()
hub.stateLock.RLock()
defer hub.stateLock.RUnlock()
cpy := make([]accounts.Wallet, 0, len(hub.wallets))
for _, wallet := range hub.wallets {
if wallet != nil {
cpy = append(cpy, wallet)
cpy = append(cpy, wallet)
}
for i := 0; i < len(cpy); i++ {
for j := i + 1; j < len(cpy); j++ {
if cpy[i].URL().Cmp(cpy[j].URL()) > 0 {
cpy[i], cpy[j] = cpy[j], cpy[i]
}
}
}
return cpy
@ -196,67 +195,77 @@ func (hub *Hub) Wallets() []accounts.Wallet {
// refreshWallets scans the devices attached to the machine and updates the
// list of wallets based on the found devices.
func (hub *Hub) refreshWallets() {
// Don't scan the USB like crazy it the user fetches wallets in a loop
hub.stateLock.RLock()
elapsed := time.Since(hub.refreshed)
hub.stateLock.RUnlock()
if elapsed < refreshThrottling {
return
}
// Retrieve all the smart card reader to check for cards
readers, err := hub.context.ListReaders()
if err != nil {
log.Error("Error listing readers", "err", err)
// This is a perverted hack, the scard library returns an error if no card
// readers are present instead of simply returning an empty list. We don't
// want to fill the user's log with errors, so filter those out.
if err.Error() != "scard: Cannot find a smart card reader." {
log.Error("Failed to enumerate smart card readers", "err", err)
}
}
// Transform the current list of wallets into the new one
hub.stateLock.Lock()
events := []accounts.WalletEvent{}
seen := make(map[string]struct{})
for _, reader := range readers {
if wallet, ok := hub.wallets[reader]; ok {
// We already know about this card; check it's still present
if err := wallet.ping(); err != nil {
log.Debug("Got error pinging wallet", "reader", reader, "err", err)
} else {
seen[reader] = struct{}{}
}
continue
}
// Mark the reader as present
seen[reader] = struct{}{}
// If we alreay know about this card, skip to the next reader, otherwise clean up
if wallet, ok := hub.wallets[reader]; ok {
if err := wallet.ping(); err == nil {
continue
}
wallet.Close()
events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletDropped})
delete(hub.wallets, reader)
}
// New card detected, try to connect to it
card, err := hub.context.Connect(reader, scard.ShareShared, scard.ProtocolAny)
if err != nil {
log.Debug("Error opening card", "reader", reader, "err", err)
log.Debug("Failed to open smart card", "reader", reader, "err", err)
continue
}
wallet := NewWallet(hub, card)
err = wallet.connect()
if err != nil {
log.Debug("Error connecting to wallet", "reader", reader, "err", err)
if err = wallet.connect(); err != nil {
log.Debug("Failed to connect to smart card", "reader", reader, "err", err)
card.Disconnect(scard.LeaveCard)
continue
}
// Card connected, start tracking in amongs the wallets
hub.wallets[reader] = wallet
events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletArrived})
log.Info("Found new smartcard wallet", "reader", reader, "publicKey", hexutil.Encode(wallet.PublicKey[:4]))
}
// Remove any wallets we no longer see
for k, wallet := range hub.wallets {
if _, ok := seen[k]; !ok {
log.Info("Wallet disconnected", "pubkey", hexutil.Encode(wallet.PublicKey[:4]), "reader", k)
// Remove any wallets no longer present
for reader, wallet := range hub.wallets {
if _, ok := seen[reader]; !ok {
wallet.Close()
events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletDropped})
delete(hub.wallets, k)
delete(hub.wallets, reader)
}
}
hub.refreshed = time.Now()
hub.stateLock.Unlock()
for _, event := range events {
hub.updateFeed.Send(event)
}
hub.refreshed = time.Now()
}
// Subscribe implements accounts.Backend, creating an async subscription to
// receive notifications on the addition or removal of wallets.
// receive notifications on the addition or removal of smart card wallets.
func (hub *Hub) Subscribe(sink chan<- accounts.WalletEvent) event.Subscription {
// We need the mutex to reliably start/stop the update loop
hub.stateLock.Lock()
@ -274,16 +283,18 @@ func (hub *Hub) Subscribe(sink chan<- accounts.WalletEvent) event.Subscription {
}
// updater is responsible for maintaining an up-to-date list of wallets managed
// by the hub, and for firing wallet addition/removal events.
// by the smart card hub, and for firing wallet addition/removal events.
func (hub *Hub) updater() {
for {
// TODO: Wait for a USB hotplug event (not supported yet) or a refresh timeout
// <-hub.changes
time.Sleep(refreshCycle)
// Run the wallet refresher
hub.stateLock.Lock()
hub.refreshWallets()
// If all our subscribers left, stop the updater
hub.stateLock.Lock()
if hub.updateScope.Count() == 0 {
hub.updating = false
hub.stateLock.Unlock()