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Use a shared device manager

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Use a shared device manager across USB devices (not yet taken
advantage of by ledger).  This reduces USB scans and abstracts
device management cleanly.

We no longer scan at regular intervals in a background thread.
This commit is contained in:
Neil Booth
2016-01-05 06:47:14 +09:00
parent 5b8e096d57
commit 3d9f321cae
6 changed files with 331 additions and 186 deletions
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198
lib/plugins.py
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@@ -44,6 +44,8 @@ class Plugins(DaemonThread):
self.plugins = {}
self.gui_name = gui_name
self.descriptions = []
self.device_manager = DeviceMgr()
for loader, name, ispkg in pkgutil.iter_modules([self.pkgpath]):
m = loader.find_module(name).load_module(name)
d = m.__dict__
@@ -212,3 +214,199 @@ class BasePlugin(PrintError):
def settings_dialog(self):
pass
class DeviceMgr(PrintError):
'''Manages hardware clients. A client communicates over a hardware
channel with the device. A client is a pair: a device ID (serial
number) and hardware port. If either change then a different
client is instantiated.
In addition to tracking device IDs, the device manager tracks
hardware wallets and manages wallet pairing. A device ID may be
paired with a wallet when it is confirmed that the hardware device
matches the wallet, i.e. they have the same master public key. A
device ID can be unpaired if e.g. it is wiped.
Because of hotplugging, a wallet must request its client
dynamically each time it is required, rather than caching it
itself.
The device manager is shared across plugins, so just one place
does hardware scans when needed. By tracking device serial
numbers the number of necessary hardware scans is reduced, e.g. if
a device is plugged into a different port the wallet is
automatically re-paired.
Wallets are informed on connect / disconnect / unpairing events.
It must implement connected(), disconnected() and unpaired()
callbacks. Being connected implies a pairing. Being disconnected
doesn't. Callbacks can happen in any thread context, and we do
them without holding the lock.
This plugin is thread-safe. Currently only USB is implemented.
'''
# Client lookup types. CACHED will look up in our client cache
# only. PRESENT will do a scan if there is no client in the cache.
# PAIRED will try and pair the wallet, which will involve requesting
# a PIN and passphrase if they are enabled
(CACHED, PRESENT, PAIRED) = range(3)
def __init__(self):
super(DeviceMgr, self).__init__()
# Keyed by wallet. The value is the device_id if the wallet
# has been paired, and None otherwise.
self.wallets = {}
# A list of clients. We create a client for every device present
# that is of a registered hardware type
self.clients = []
# What we recognise. Keyed by (vendor_id, product_id) pairs,
# the value is a handler for those devices. The handler must
# implement
self.recognised_hardware = {}
# For synchronization
self.lock = threading.RLock()
def register_devices(self, handler, device_pairs):
for pair in device_pairs:
self.recognised_hardware[pair] = handler
def close_client(self, client):
with self.lock:
if client in self.clients:
self.clients.remove(client)
client.close()
def close_wallet(self, wallet):
# Remove the wallet from our list; close any client
with self.lock:
device_id = self.wallets.pop(wallet, None)
self.close_client(self.client_by_device_id(device_id))
def clients_of_type(self, classinfo):
with self.lock:
return [client for client in self.clients
if isinstance(client, classinfo)]
def client_by_device_id(self, device_id):
with self.lock:
for client in self.clients:
if client.device_id() == device_id:
return client
return None
def wallet_by_device_id(self, device_id):
with self.lock:
for wallet, wallet_device_id in self.wallets.items():
if wallet_device_id == device_id:
return wallet
return None
def paired_wallets(self):
with self.lock:
return [wallet for (wallet, device_id) in self.wallets.items()
if device_id is not None]
def pair_wallet(self, wallet, client):
assert client in self.clients
self.print_error("paired:", wallet, client)
self.wallets[wallet] = client.device_id()
client.pair_wallet(wallet)
wallet.connected()
def scan_devices(self):
# All currently supported hardware libraries use hid, so we
# assume it here. This can be easily abstracted if necessary.
# Note this import must be local so those without hardware
# wallet libraries are not affected.
import hid
self.print_error("scanning devices...")
# First see what's connected that we know about
devices = {}
for d in hid.enumerate(0, 0):
product_key = (d['vendor_id'], d['product_id'])
device_id = d['serial_number']
path = d['path']
handler = self.recognised_hardware.get(product_key)
if handler:
devices[device_id] = (handler, path, product_key)
# Now find out what was disconnected
with self.lock:
disconnected = [client for client in self.clients
if not client.device_id() in devices]
# Close disconnected clients after informing their wallets
for client in disconnected:
wallet = self.wallet_by_device_id(client.device_id())
if wallet:
wallet.disconnected()
self.close_client(client)
# Now see if any new devices are present.
for device_id, (handler, path, product_key) in devices.items():
try:
client = handler.create_client(path, product_key)
except BaseException as e:
self.print_error("could not create client", str(e))
client = None
if client:
self.print_error("client created for", path)
with self.lock:
self.clients.append(client)
# Inform re-paired wallet
wallet = self.wallet_by_device_id(device_id)
if wallet:
self.pair_wallet(wallet, client)
def get_client(self, wallet, lookup=PAIRED):
'''Returns a client for the wallet, or None if one could not be
found.'''
with self.lock:
device_id = self.wallets.get(wallet)
client = self.client_by_device_id(device_id)
if client:
return client
if lookup == DeviceMgr.CACHED:
return None
first_address, derivation = wallet.first_address()
# Wallets don't have a first address in the install wizard
# until account creation
if not first_address:
self.print_error("no first address for ", wallet)
return None
# We didn't find it, so scan for new devices. We scan as
# little as possible: some people report a USB scan is slow on
# Linux when a Trezor is plugged in
self.scan_devices()
with self.lock:
# Maybe the scan found it? If the wallet has a device_id
# from a prior pairing, we can determine success now.
if device_id:
return self.client_by_device_id(device_id)
# Stop here if no wake and we couldn't find it.
if lookup == DeviceMgr.PRESENT:
return None
# The wallet has not been previously paired, so get the
# first address of all unpaired clients and compare.
for client in self.clients:
# If already paired skip it
if self.wallet_by_device_id(client.device_id()):
continue
# This will trigger a PIN/passphrase entry request
if client.first_address(wallet, derivation) == first_address:
self.pair_wallet(wallet, client)
return client
# Not found
return None