421 lines
14 KiB
Python
421 lines
14 KiB
Python
|
import array
|
||
|
|
from contextlib import contextmanager
|
||
|
|
import errno
|
||
|
|
from itertools import count
|
||
|
|
import logging
|
||
|
|
from typing import Optional
|
||
|
|
|
||
|
|
try:
|
||
|
|
from contextlib import asynccontextmanager # Python 3.7
|
||
|
|
except ImportError:
|
||
|
|
from async_generator import asynccontextmanager # Backport for Python 3.6
|
||
|
|
|
||
|
|
from outcome import Value, Error
|
||
|
|
import trio
|
||
|
|
from trio.abc import Channel
|
||
|
|
|
||
|
|
from jeepney.auth import Authenticator, BEGIN
|
||
|
|
from jeepney.bus import get_bus
|
||
|
|
from jeepney.fds import FileDescriptor, fds_buf_size
|
||
|
|
from jeepney.low_level import Parser, MessageType, Message
|
||
|
|
from jeepney.wrappers import ProxyBase, unwrap_msg
|
||
|
|
from jeepney.bus_messages import message_bus
|
||
|
|
from .common import (
|
||
|
|
MessageFilters, FilterHandle, ReplyMatcher, RouterClosed, check_replyable,
|
||
|
|
)
|
||
|
|
|
||
|
|
log = logging.getLogger(__name__)
|
||
|
|
|
||
|
|
__all__ = [
|
||
|
|
'open_dbus_connection',
|
||
|
|
'open_dbus_router',
|
||
|
|
'Proxy',
|
||
|
|
]
|
||
|
|
|
||
|
|
|
||
|
|
# The function below is copied from trio, which is under the MIT license:
|
||
|
|
|
||
|
|
# Permission is hereby granted, free of charge, to any person obtaining
|
||
|
|
# a copy of this software and associated documentation files (the
|
||
|
|
# "Software"), to deal in the Software without restriction, including
|
||
|
|
# without limitation the rights to use, copy, modify, merge, publish,
|
||
|
|
# distribute, sublicense, and/or sell copies of the Software, and to
|
||
|
|
# permit persons to whom the Software is furnished to do so, subject to
|
||
|
|
# the following conditions:
|
||
|
|
#
|
||
|
|
# The above copyright notice and this permission notice shall be
|
||
|
|
# included in all copies or substantial portions of the Software.
|
||
|
|
@contextmanager
|
||
|
|
def _translate_socket_errors_to_stream_errors():
|
||
|
|
try:
|
||
|
|
yield
|
||
|
|
except OSError as exc:
|
||
|
|
if exc.errno in {errno.EBADF, errno.ENOTSOCK}:
|
||
|
|
# EBADF on Unix, ENOTSOCK on Windows
|
||
|
|
raise trio.ClosedResourceError("this socket was already closed") from None
|
||
|
|
else:
|
||
|
|
raise trio.BrokenResourceError(
|
||
|
|
"socket connection broken: {}".format(exc)
|
||
|
|
) from exc
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
class DBusConnection(Channel):
|
||
|
|
"""A plain D-Bus connection with no matching of replies.
|
||
|
|
|
||
|
|
This doesn't run any separate tasks: sending and receiving are done in
|
||
|
|
the task that calls those methods. It's suitable for implementing servers:
|
||
|
|
several worker tasks can receive requests and send replies.
|
||
|
|
For a typical client pattern, see :class:`DBusRouter`.
|
||
|
|
|
||
|
|
Implements trio's channel interface for Message objects.
|
||
|
|
"""
|
||
|
|
def __init__(self, socket, enable_fds=False):
|
||
|
|
self.socket = socket
|
||
|
|
self.enable_fds = enable_fds
|
||
|
|
self.parser = Parser()
|
||
|
|
self.outgoing_serial = count(start=1)
|
||
|
|
self.unique_name = None
|
||
|
|
self.send_lock = trio.Lock()
|
||
|
|
self.recv_lock = trio.Lock()
|
||
|
|
self._leftover_to_send = None # type: Optional[memoryview]
|
||
|
|
|
||
|
|
async def send(self, message: Message, *, serial=None):
|
||
|
|
"""Serialise and send a :class:`~.Message` object"""
|
||
|
|
async with self.send_lock:
|
||
|
|
if serial is None:
|
||
|
|
serial = next(self.outgoing_serial)
|
||
|
|
fds = array.array('i') if self.enable_fds else None
|
||
|
|
data = message.serialise(serial, fds=fds)
|
||
|
|
await self._send_data(data, fds)
|
||
|
|
|
||
|
|
# _send_data is copied & modified from trio's SocketStream.send_all() .
|
||
|
|
# See above for the MIT license.
|
||
|
|
async def _send_data(self, data: bytes, fds):
|
||
|
|
if self.socket.did_shutdown_SHUT_WR:
|
||
|
|
raise trio.ClosedResourceError("can't send data after sending EOF")
|
||
|
|
|
||
|
|
with _translate_socket_errors_to_stream_errors():
|
||
|
|
if self._leftover_to_send:
|
||
|
|
# A previous message was partly sent - finish sending it now.
|
||
|
|
await self._send_remainder(self._leftover_to_send)
|
||
|
|
|
||
|
|
with memoryview(data) as data:
|
||
|
|
if fds:
|
||
|
|
sent = await self.socket.sendmsg([data], [(
|
||
|
|
trio.socket.SOL_SOCKET, trio.socket.SCM_RIGHTS, fds
|
||
|
|
)])
|
||
|
|
else:
|
||
|
|
sent = await self.socket.send(data)
|
||
|
|
|
||
|
|
await self._send_remainder(data, sent)
|
||
|
|
|
||
|
|
async def _send_remainder(self, data: memoryview, already_sent=0):
|
||
|
|
try:
|
||
|
|
while already_sent < len(data):
|
||
|
|
with data[already_sent:] as remaining:
|
||
|
|
sent = await self.socket.send(remaining)
|
||
|
|
already_sent += sent
|
||
|
|
self._leftover_to_send = None
|
||
|
|
except trio.Cancelled:
|
||
|
|
# Sending cancelled mid-message. Keep track of the remaining data
|
||
|
|
# so it can be sent before the next message, otherwise the next
|
||
|
|
# message won't be recognised.
|
||
|
|
self._leftover_to_send = data[already_sent:]
|
||
|
|
raise
|
||
|
|
|
||
|
|
async def receive(self) -> Message:
|
||
|
|
"""Return the next available message from the connection"""
|
||
|
|
async with self.recv_lock:
|
||
|
|
while True:
|
||
|
|
msg = self.parser.get_next_message()
|
||
|
|
if msg is not None:
|
||
|
|
return msg
|
||
|
|
|
||
|
|
# Once data is read, it must be given to the parser with no
|
||
|
|
# checkpoints (where the task could be cancelled).
|
||
|
|
b, fds = await self._read_data()
|
||
|
|
if not b:
|
||
|
|
raise trio.EndOfChannel("Socket closed at the other end")
|
||
|
|
self.parser.add_data(b, fds)
|
||
|
|
|
||
|
|
async def _read_data(self):
|
||
|
|
if self.enable_fds:
|
||
|
|
nbytes = self.parser.bytes_desired()
|
||
|
|
with _translate_socket_errors_to_stream_errors():
|
||
|
|
data, ancdata, flags, _ = await self.socket.recvmsg(
|
||
|
|
nbytes, fds_buf_size()
|
||
|
|
)
|
||
|
|
if flags & getattr(trio.socket, 'MSG_CTRUNC', 0):
|
||
|
|
self._close()
|
||
|
|
raise RuntimeError("Unable to receive all file descriptors")
|
||
|
|
return data, FileDescriptor.from_ancdata(ancdata)
|
||
|
|
|
||
|
|
else: # not self.enable_fds
|
||
|
|
with _translate_socket_errors_to_stream_errors():
|
||
|
|
data = await self.socket.recv(4096)
|
||
|
|
return data, []
|
||
|
|
|
||
|
|
def _close(self):
|
||
|
|
self.socket.close()
|
||
|
|
self._leftover_to_send = None
|
||
|
|
|
||
|
|
# Our closing is currently sync, but AsyncResource objects must have aclose
|
||
|
|
async def aclose(self):
|
||
|
|
"""Close the D-Bus connection"""
|
||
|
|
self._close()
|
||
|
|
|
||
|
|
@asynccontextmanager
|
||
|
|
async def router(self):
|
||
|
|
"""Temporarily wrap this connection as a :class:`DBusRouter`
|
||
|
|
|
||
|
|
To be used like::
|
||
|
|
|
||
|
|
async with conn.router() as req:
|
||
|
|
reply = await req.send_and_get_reply(msg)
|
||
|
|
|
||
|
|
While the router is running, you shouldn't use :meth:`receive`.
|
||
|
|
Once the router is closed, you can use the plain connection again.
|
||
|
|
"""
|
||
|
|
async with trio.open_nursery() as nursery:
|
||
|
|
router = DBusRouter(self)
|
||
|
|
await router.start(nursery)
|
||
|
|
try:
|
||
|
|
yield router
|
||
|
|
finally:
|
||
|
|
await router.aclose()
|
||
|
|
|
||
|
|
|
||
|
|
async def open_dbus_connection(bus='SESSION', *, enable_fds=False) -> DBusConnection:
|
||
|
|
"""Open a plain D-Bus connection
|
||
|
|
|
||
|
|
:return: :class:`DBusConnection`
|
||
|
|
"""
|
||
|
|
bus_addr = get_bus(bus)
|
||
|
|
sock : trio.SocketStream = await trio.open_unix_socket(bus_addr)
|
||
|
|
|
||
|
|
# Authentication
|
||
|
|
authr = Authenticator(enable_fds=enable_fds)
|
||
|
|
for req_data in authr:
|
||
|
|
await sock.send_all(req_data)
|
||
|
|
authr.feed(await sock.receive_some())
|
||
|
|
await sock.send_all(BEGIN)
|
||
|
|
|
||
|
|
conn = DBusConnection(sock.socket, enable_fds=enable_fds)
|
||
|
|
|
||
|
|
# Say *Hello* to the message bus - this must be the first message, and the
|
||
|
|
# reply gives us our unique name.
|
||
|
|
async with conn.router() as router:
|
||
|
|
reply = await router.send_and_get_reply(message_bus.Hello())
|
||
|
|
conn.unique_name = reply.body[0]
|
||
|
|
|
||
|
|
return conn
|
||
|
|
|
||
|
|
|
||
|
|
class TrioFilterHandle(FilterHandle):
|
||
|
|
def __init__(self, filters: MessageFilters, rule, send_chn, recv_chn):
|
||
|
|
super().__init__(filters, rule, recv_chn)
|
||
|
|
self.send_channel = send_chn
|
||
|
|
|
||
|
|
@property
|
||
|
|
def receive_channel(self):
|
||
|
|
return self.queue
|
||
|
|
|
||
|
|
async def aclose(self):
|
||
|
|
self.close()
|
||
|
|
await self.send_channel.aclose()
|
||
|
|
|
||
|
|
async def __aenter__(self):
|
||
|
|
return self.queue
|
||
|
|
|
||
|
|
async def __aexit__(self, exc_type, exc_val, exc_tb):
|
||
|
|
await self.aclose()
|
||
|
|
|
||
|
|
|
||
|
|
class Future:
|
||
|
|
"""A very simple Future for trio based on `trio.Event`."""
|
||
|
|
def __init__(self):
|
||
|
|
self._outcome = None
|
||
|
|
self._event = trio.Event()
|
||
|
|
|
||
|
|
def set_result(self, result):
|
||
|
|
self._outcome = Value(result)
|
||
|
|
self._event.set()
|
||
|
|
|
||
|
|
def set_exception(self, exc):
|
||
|
|
self._outcome = Error(exc)
|
||
|
|
self._event.set()
|
||
|
|
|
||
|
|
async def get(self):
|
||
|
|
await self._event.wait()
|
||
|
|
return self._outcome.unwrap()
|
||
|
|
|
||
|
|
|
||
|
|
class DBusRouter:
|
||
|
|
"""A client D-Bus connection which can wait for replies.
|
||
|
|
|
||
|
|
This runs a separate receiver task and dispatches received messages.
|
||
|
|
"""
|
||
|
|
_nursery_mgr = None
|
||
|
|
_rcv_cancel_scope = None
|
||
|
|
|
||
|
|
def __init__(self, conn: DBusConnection):
|
||
|
|
self._conn = conn
|
||
|
|
self._replies = ReplyMatcher()
|
||
|
|
self._filters = MessageFilters()
|
||
|
|
|
||
|
|
@property
|
||
|
|
def unique_name(self):
|
||
|
|
return self._conn.unique_name
|
||
|
|
|
||
|
|
async def send(self, message, *, serial=None):
|
||
|
|
"""Send a message, don't wait for a reply
|
||
|
|
"""
|
||
|
|
await self._conn.send(message, serial=serial)
|
||
|
|
|
||
|
|
async def send_and_get_reply(self, message) -> Message:
|
||
|
|
"""Send a method call message and wait for the reply
|
||
|
|
|
||
|
|
Returns the reply message (method return or error message type).
|
||
|
|
"""
|
||
|
|
check_replyable(message)
|
||
|
|
if self._rcv_cancel_scope is None:
|
||
|
|
raise RouterClosed("This DBusRouter has stopped")
|
||
|
|
|
||
|
|
serial = next(self._conn.outgoing_serial)
|
||
|
|
|
||
|
|
with self._replies.catch(serial, Future()) as reply_fut:
|
||
|
|
await self.send(message, serial=serial)
|
||
|
|
return (await reply_fut.get())
|
||
|
|
|
||
|
|
def filter(self, rule, *, channel: Optional[trio.MemorySendChannel]=None, bufsize=1):
|
||
|
|
"""Create a filter for incoming messages
|
||
|
|
|
||
|
|
Usage::
|
||
|
|
|
||
|
|
async with router.filter(rule) as receive_channel:
|
||
|
|
matching_msg = await receive_channel.receive()
|
||
|
|
|
||
|
|
# OR:
|
||
|
|
send_chan, recv_chan = trio.open_memory_channel(1)
|
||
|
|
async with router.filter(rule, channel=send_chan):
|
||
|
|
matching_msg = await recv_chan.receive()
|
||
|
|
|
||
|
|
If the channel fills up,
|
||
|
|
The sending end of the channel is closed when leaving the ``async with``
|
||
|
|
block, whether or not it was passed in.
|
||
|
|
|
||
|
|
:param jeepney.MatchRule rule: Catch messages matching this rule
|
||
|
|
:param trio.MemorySendChannel channel: Send matching messages here
|
||
|
|
:param int bufsize: If no channel is passed in, create one with this size
|
||
|
|
"""
|
||
|
|
if channel is None:
|
||
|
|
channel, recv_channel = trio.open_memory_channel(bufsize)
|
||
|
|
else:
|
||
|
|
recv_channel = None
|
||
|
|
return TrioFilterHandle(self._filters, rule, channel, recv_channel)
|
||
|
|
|
||
|
|
# Task management -------------------------------------------
|
||
|
|
|
||
|
|
async def start(self, nursery: trio.Nursery):
|
||
|
|
if self._rcv_cancel_scope is not None:
|
||
|
|
raise RuntimeError("DBusRouter receiver task is already running")
|
||
|
|
self._rcv_cancel_scope = await nursery.start(self._receiver)
|
||
|
|
|
||
|
|
async def aclose(self):
|
||
|
|
"""Stop the sender & receiver tasks"""
|
||
|
|
# It doesn't matter if we receive a partial message - the connection
|
||
|
|
# should ensure that whatever is received is fed to the parser.
|
||
|
|
if self._rcv_cancel_scope is not None:
|
||
|
|
self._rcv_cancel_scope.cancel()
|
||
|
|
self._rcv_cancel_scope = None
|
||
|
|
|
||
|
|
# Ensure trio checkpoint
|
||
|
|
await trio.sleep(0)
|
||
|
|
|
||
|
|
# Code to run in receiver task ------------------------------------
|
||
|
|
|
||
|
|
def _dispatch(self, msg: Message):
|
||
|
|
"""Handle one received message"""
|
||
|
|
if self._replies.dispatch(msg):
|
||
|
|
return
|
||
|
|
|
||
|
|
for filter in self._filters.matches(msg):
|
||
|
|
try:
|
||
|
|
filter.send_channel.send_nowait(msg)
|
||
|
|
except trio.WouldBlock:
|
||
|
|
pass
|
||
|
|
|
||
|
|
async def _receiver(self, task_status=trio.TASK_STATUS_IGNORED):
|
||
|
|
"""Receiver loop - runs in a separate task"""
|
||
|
|
with trio.CancelScope() as cscope:
|
||
|
|
self.is_running = True
|
||
|
|
task_status.started(cscope)
|
||
|
|
try:
|
||
|
|
while True:
|
||
|
|
msg = await self._conn.receive()
|
||
|
|
self._dispatch(msg)
|
||
|
|
finally:
|
||
|
|
self.is_running = False
|
||
|
|
# Send errors to any tasks still waiting for a message.
|
||
|
|
self._replies.drop_all()
|
||
|
|
|
||
|
|
# Closing a memory channel can't block, but it only has an
|
||
|
|
# async close method, so we need to shield it from cancellation.
|
||
|
|
with trio.move_on_after(3) as cleanup_scope:
|
||
|
|
for filter in self._filters.filters.values():
|
||
|
|
cleanup_scope.shield = True
|
||
|
|
await filter.send_channel.aclose()
|
||
|
|
|
||
|
|
|
||
|
|
class Proxy(ProxyBase):
|
||
|
|
"""A trio proxy for calling D-Bus methods
|
||
|
|
|
||
|
|
You can call methods on the proxy object, such as ``await bus_proxy.Hello()``
|
||
|
|
to make a method call over D-Bus and wait for a reply. It will either
|
||
|
|
return a tuple of returned data, or raise :exc:`.DBusErrorResponse`.
|
||
|
|
The methods available are defined by the message generator you wrap.
|
||
|
|
|
||
|
|
:param msggen: A message generator object.
|
||
|
|
:param ~trio.DBusRouter router: Router to send and receive messages.
|
||
|
|
"""
|
||
|
|
def __init__(self, msggen, router):
|
||
|
|
super().__init__(msggen)
|
||
|
|
if not isinstance(router, DBusRouter):
|
||
|
|
raise TypeError("Proxy can only be used with DBusRequester")
|
||
|
|
self._router = router
|
||
|
|
|
||
|
|
def _method_call(self, make_msg):
|
||
|
|
async def inner(*args, **kwargs):
|
||
|
|
msg = make_msg(*args, **kwargs)
|
||
|
|
assert msg.header.message_type is MessageType.method_call
|
||
|
|
reply = await self._router.send_and_get_reply(msg)
|
||
|
|
return unwrap_msg(reply)
|
||
|
|
|
||
|
|
return inner
|
||
|
|
|
||
|
|
|
||
|
|
@asynccontextmanager
|
||
|
|
async def open_dbus_router(bus='SESSION', *, enable_fds=False):
|
||
|
|
"""Open a D-Bus 'router' to send and receive messages.
|
||
|
|
|
||
|
|
Use as an async context manager::
|
||
|
|
|
||
|
|
async with open_dbus_router() as req:
|
||
|
|
...
|
||
|
|
|
||
|
|
:param str bus: 'SESSION' or 'SYSTEM' or a supported address.
|
||
|
|
:return: :class:`DBusRouter`
|
||
|
|
|
||
|
|
This is a shortcut for::
|
||
|
|
|
||
|
|
conn = await open_dbus_connection()
|
||
|
|
async with conn:
|
||
|
|
async with conn.router() as req:
|
||
|
|
...
|
||
|
|
"""
|
||
|
|
conn = await open_dbus_connection(bus, enable_fds=enable_fds)
|
||
|
|
async with conn:
|
||
|
|
async with conn.router() as rtr:
|
||
|
|
yield rtr
|