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trezor-firmware/python/trezorlib/transport/__init__.py
2019-06-17 20:28:29 +02:00

151 lines
4.8 KiB
Python

# This file is part of the Trezor project.
#
# Copyright (C) 2012-2019 SatoshiLabs and contributors
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# This library 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 Lesser General Public License for more details.
#
# You should have received a copy of the License along with this library.
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
import logging
from typing import Iterable, List, Type
from ..exceptions import TrezorException
from ..protobuf import MessageType
LOG = logging.getLogger(__name__)
# USB vendor/product IDs for Trezors
DEV_TREZOR1 = (0x534C, 0x0001)
DEV_TREZOR2 = (0x1209, 0x53C1)
DEV_TREZOR2_BL = (0x1209, 0x53C0)
TREZORS = {DEV_TREZOR1, DEV_TREZOR2, DEV_TREZOR2_BL}
UDEV_RULES_STR = """
Do you have udev rules installed?
https://github.com/trezor/trezor-common/blob/master/udev/51-trezor.rules
""".strip()
class TransportException(TrezorException):
pass
class Transport:
"""Raw connection to a Trezor device.
Transport subclass represents a kind of communication link: Trezor Bridge, WebUSB
or USB-HID connection, or UDP socket of listening emulator(s).
It can also enumerate devices available over this communication link, and return
them as instances.
Transport instance is a thing that:
- can be identified and requested by a string URI-like path
- can open and close sessions, which enclose related operations
- can read and write protobuf messages
You need to implement a new Transport subclass if you invent a new way to connect
a Trezor device to a computer.
"""
PATH_PREFIX = None # type: str
ENABLED = False
def __str__(self) -> str:
return self.get_path()
def get_path(self) -> str:
raise NotImplementedError
def begin_session(self) -> None:
raise NotImplementedError
def end_session(self) -> None:
raise NotImplementedError
def read(self) -> MessageType:
raise NotImplementedError
def write(self, message: MessageType) -> None:
raise NotImplementedError
@classmethod
def enumerate(cls) -> Iterable["Transport"]:
raise NotImplementedError
@classmethod
def find_by_path(cls, path: str, prefix_search: bool = False) -> "Transport":
for device in cls.enumerate():
if (
path is None
or device.get_path() == path
or (prefix_search and device.get_path().startswith(path))
):
return device
raise TransportException(
"{} device not found: {}".format(cls.PATH_PREFIX, path)
)
def all_transports() -> Iterable[Type[Transport]]:
from .bridge import BridgeTransport
from .hid import HidTransport
from .udp import UdpTransport
from .webusb import WebUsbTransport
return set(
cls
for cls in (BridgeTransport, HidTransport, UdpTransport, WebUsbTransport)
if cls.ENABLED
)
def enumerate_devices() -> Iterable[Transport]:
devices = [] # type: List[Transport]
for transport in all_transports():
name = transport.__name__
try:
found = list(transport.enumerate())
LOG.info("Enumerating {}: found {} devices".format(name, len(found)))
devices.extend(found)
except NotImplementedError:
LOG.error("{} does not implement device enumeration".format(name))
except Exception as e:
excname = e.__class__.__name__
LOG.error("Failed to enumerate {}. {}: {}".format(name, excname, e))
return devices
def get_transport(path: str = None, prefix_search: bool = False) -> Transport:
if path is None:
try:
return next(iter(enumerate_devices()))
except StopIteration:
raise TransportException("No Trezor device found") from None
# Find whether B is prefix of A (transport name is part of the path)
# or A is prefix of B (path is a prefix, or a name, of transport).
# This naively expects that no two transports have a common prefix.
def match_prefix(a: str, b: str) -> bool:
return a.startswith(b) or b.startswith(a)
LOG.info(
"looking for device by {}: {}".format(
"prefix" if prefix_search else "full path", path
)
)
transports = [t for t in all_transports() if match_prefix(path, t.PATH_PREFIX)]
if transports:
return transports[0].find_by_path(path, prefix_search=prefix_search)
raise TransportException("Could not find device by path: {}".format(path))