280 lines
10 KiB
Go
280 lines
10 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package usbwallet
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import (
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"errors"
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"runtime"
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"sync"
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"sync/atomic"
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"time"
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"github.com/ethereum/go-ethereum/accounts"
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"github.com/ethereum/go-ethereum/event"
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"github.com/ethereum/go-ethereum/log"
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"github.com/karalabe/usb"
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)
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// LedgerScheme is the protocol scheme prefixing account and wallet URLs.
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const LedgerScheme = "ledger"
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// TrezorScheme is the protocol scheme prefixing account and wallet URLs.
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const TrezorScheme = "trezor"
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// refreshCycle is the maximum time between wallet refreshes (if USB hotplug
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// notifications don't work).
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const refreshCycle = time.Second
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// refreshThrottling is the minimum time between wallet refreshes to avoid USB
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// trashing.
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const refreshThrottling = 500 * time.Millisecond
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// Hub is a accounts.Backend that can find and handle generic USB hardware wallets.
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type Hub struct {
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scheme string // Protocol scheme prefixing account and wallet URLs.
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vendorID uint16 // USB vendor identifier used for device discovery
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productIDs []uint16 // USB product identifiers used for device discovery
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usageID uint16 // USB usage page identifier used for macOS device discovery
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endpointID int // USB endpoint identifier used for non-macOS device discovery
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makeDriver func(log.Logger) driver // Factory method to construct a vendor specific driver
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refreshed time.Time // Time instance when the list of wallets was last refreshed
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wallets []accounts.Wallet // List of USB wallet devices currently tracking
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updateFeed event.Feed // Event feed to notify wallet additions/removals
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updateScope event.SubscriptionScope // Subscription scope tracking current live listeners
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updating bool // Whether the event notification loop is running
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quit chan chan error
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stateLock sync.RWMutex // Protects the internals of the hub from racey access
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// TODO(karalabe): remove if hotplug lands on Windows
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commsPend int // Number of operations blocking enumeration
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commsLock sync.Mutex // Lock protecting the pending counter and enumeration
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enumFails uint32 // Number of times enumeration has failed
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}
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// NewLedgerHub creates a new hardware wallet manager for Ledger devices.
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func NewLedgerHub() (*Hub, error) {
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return newHub(LedgerScheme, 0x2c97, []uint16{
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// Original product IDs
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0x0000, /* Ledger Blue */
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0x0001, /* Ledger Nano S */
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0x0004, /* Ledger Nano X */
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// Upcoming product IDs: https://www.ledger.com/2019/05/17/windows-10-update-sunsetting-u2f-tunnel-transport-for-ledger-devices/
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0x0015, /* HID + U2F + WebUSB Ledger Blue */
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0x1015, /* HID + U2F + WebUSB Ledger Nano S */
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0x4015, /* HID + U2F + WebUSB Ledger Nano X */
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0x0011, /* HID + WebUSB Ledger Blue */
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0x1011, /* HID + WebUSB Ledger Nano S */
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0x4011, /* HID + WebUSB Ledger Nano X */
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}, 0xffa0, 0, newLedgerDriver)
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}
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// NewTrezorHubWithHID creates a new hardware wallet manager for Trezor devices.
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func NewTrezorHubWithHID() (*Hub, error) {
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return newHub(TrezorScheme, 0x534c, []uint16{0x0001 /* Trezor HID */}, 0xff00, 0, newTrezorDriver)
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}
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// NewTrezorHubWithWebUSB creates a new hardware wallet manager for Trezor devices with
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// firmware version > 1.8.0
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func NewTrezorHubWithWebUSB() (*Hub, error) {
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return newHub(TrezorScheme, 0x1209, []uint16{0x53c1 /* Trezor WebUSB */}, 0xffff /* No usage id on webusb, don't match unset (0) */, 0, newTrezorDriver)
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}
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// newHub creates a new hardware wallet manager for generic USB devices.
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func newHub(scheme string, vendorID uint16, productIDs []uint16, usageID uint16, endpointID int, makeDriver func(log.Logger) driver) (*Hub, error) {
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if !usb.Supported() {
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return nil, errors.New("unsupported platform")
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}
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hub := &Hub{
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scheme: scheme,
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vendorID: vendorID,
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productIDs: productIDs,
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usageID: usageID,
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endpointID: endpointID,
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makeDriver: makeDriver,
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quit: make(chan chan error),
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}
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hub.refreshWallets()
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return hub, nil
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}
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// Wallets implements accounts.Backend, returning all the currently tracked USB
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// devices that appear to be hardware wallets.
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func (hub *Hub) Wallets() []accounts.Wallet {
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// Make sure the list of wallets is up to date
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hub.refreshWallets()
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hub.stateLock.RLock()
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defer hub.stateLock.RUnlock()
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cpy := make([]accounts.Wallet, len(hub.wallets))
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copy(cpy, hub.wallets)
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return cpy
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}
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// refreshWallets scans the USB devices attached to the machine and updates the
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// list of wallets based on the found devices.
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func (hub *Hub) refreshWallets() {
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// Don't scan the USB like crazy it the user fetches wallets in a loop
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hub.stateLock.RLock()
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elapsed := time.Since(hub.refreshed)
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hub.stateLock.RUnlock()
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if elapsed < refreshThrottling {
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return
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}
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// If USB enumeration is continually failing, don't keep trying indefinitely
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if atomic.LoadUint32(&hub.enumFails) > 2 {
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return
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}
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// Retrieve the current list of USB wallet devices
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var devices []usb.DeviceInfo
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if runtime.GOOS == "linux" {
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// hidapi on Linux opens the device during enumeration to retrieve some infos,
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// breaking the Ledger protocol if that is waiting for user confirmation. This
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// is a bug acknowledged at Ledger, but it won't be fixed on old devices so we
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// need to prevent concurrent comms ourselves. The more elegant solution would
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// be to ditch enumeration in favor of hotplug events, but that don't work yet
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// on Windows so if we need to hack it anyway, this is more elegant for now.
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hub.commsLock.Lock()
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if hub.commsPend > 0 { // A confirmation is pending, don't refresh
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hub.commsLock.Unlock()
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return
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}
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}
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infos, err := usb.Enumerate(hub.vendorID, 0)
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if err != nil {
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failcount := atomic.AddUint32(&hub.enumFails, 1)
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if runtime.GOOS == "linux" {
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// See rationale before the enumeration why this is needed and only on Linux.
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hub.commsLock.Unlock()
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}
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log.Error("Failed to enumerate USB devices", "hub", hub.scheme,
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"vendor", hub.vendorID, "failcount", failcount, "err", err)
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return
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}
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atomic.StoreUint32(&hub.enumFails, 0)
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for _, info := range infos {
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for _, id := range hub.productIDs {
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// Windows and Macos use UsageID matching, Linux uses Interface matching
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if info.ProductID == id && (info.UsagePage == hub.usageID || info.Interface == hub.endpointID) {
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devices = append(devices, info)
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break
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}
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}
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}
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if runtime.GOOS == "linux" {
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// See rationale before the enumeration why this is needed and only on Linux.
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hub.commsLock.Unlock()
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}
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// Transform the current list of wallets into the new one
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hub.stateLock.Lock()
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var (
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wallets = make([]accounts.Wallet, 0, len(devices))
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events []accounts.WalletEvent
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)
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for _, device := range devices {
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url := accounts.URL{Scheme: hub.scheme, Path: device.Path}
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// Drop wallets in front of the next device or those that failed for some reason
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for len(hub.wallets) > 0 {
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// Abort if we're past the current device and found an operational one
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_, failure := hub.wallets[0].Status()
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if hub.wallets[0].URL().Cmp(url) >= 0 || failure == nil {
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break
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}
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// Drop the stale and failed devices
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events = append(events, accounts.WalletEvent{Wallet: hub.wallets[0], Kind: accounts.WalletDropped})
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hub.wallets = hub.wallets[1:]
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}
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// If there are no more wallets or the device is before the next, wrap new wallet
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if len(hub.wallets) == 0 || hub.wallets[0].URL().Cmp(url) > 0 {
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logger := log.New("url", url)
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wallet := &wallet{hub: hub, driver: hub.makeDriver(logger), url: &url, info: device, log: logger}
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events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletArrived})
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wallets = append(wallets, wallet)
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continue
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}
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// If the device is the same as the first wallet, keep it
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if hub.wallets[0].URL().Cmp(url) == 0 {
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wallets = append(wallets, hub.wallets[0])
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hub.wallets = hub.wallets[1:]
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continue
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}
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}
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// Drop any leftover wallets and set the new batch
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for _, wallet := range hub.wallets {
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events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletDropped})
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}
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hub.refreshed = time.Now()
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hub.wallets = wallets
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hub.stateLock.Unlock()
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// Fire all wallet events and return
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for _, event := range events {
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hub.updateFeed.Send(event)
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}
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}
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// Subscribe implements accounts.Backend, creating an async subscription to
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// receive notifications on the addition or removal of USB wallets.
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func (hub *Hub) Subscribe(sink chan<- accounts.WalletEvent) event.Subscription {
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// We need the mutex to reliably start/stop the update loop
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hub.stateLock.Lock()
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defer hub.stateLock.Unlock()
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// Subscribe the caller and track the subscriber count
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sub := hub.updateScope.Track(hub.updateFeed.Subscribe(sink))
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// Subscribers require an active notification loop, start it
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if !hub.updating {
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hub.updating = true
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go hub.updater()
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}
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return sub
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}
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// updater is responsible for maintaining an up-to-date list of wallets managed
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// by the USB hub, and for firing wallet addition/removal events.
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func (hub *Hub) updater() {
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for {
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// TODO: Wait for a USB hotplug event (not supported yet) or a refresh timeout
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// <-hub.changes
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time.Sleep(refreshCycle)
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// Run the wallet refresher
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hub.refreshWallets()
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// If all our subscribers left, stop the updater
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hub.stateLock.Lock()
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if hub.updateScope.Count() == 0 {
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hub.updating = false
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hub.stateLock.Unlock()
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return
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}
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hub.stateLock.Unlock()
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}
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}
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