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python/aqmp: drop _bind_hack()

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_bind_hack() was a quick fix to allow async QMP to call bind(2) prior to
calling listen(2) and accept(2). This wasn't sufficient to fully address
the race condition present in synchronous clients.

With the race condition in legacy.py fixed (see the previous commit),
there are no longer any users of _bind_hack(). Drop it.

Fixes: b0b662bb2b
Signed-off-by: John Snow <jsnow@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20220225205948.3693480-11-jsnow@redhat.com
[Expanded commit message. --js]
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
John Snow 2022-02-25 15:59:48 -05:00
parent 673856f9d8
commit 4c1fe7003c
2 changed files with 4 additions and 39 deletions
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2
python/qemu/aqmp/legacy.py
View File

@ -57,7 +57,7 @@ class QEMUMonitorProtocol(qemu.qmp.QEMUMonitorProtocol):
self._timeout: Optional[float] = None
if server:
self._sync(self._aqmp.start_server(address))
self._sync(self._aqmp.start_server(self._address))
_T = TypeVar('_T')

41
python/qemu/aqmp/protocol.py
View File

@ -18,7 +18,6 @@ from asyncio import StreamReader, StreamWriter
from enum import Enum
from functools import wraps
import logging
import socket
from ssl import SSLContext
from typing import (
Any,
@ -242,9 +241,6 @@ class AsyncProtocol(Generic[T]):
self._runstate = Runstate.IDLE
self._runstate_changed: Optional[asyncio.Event] = None
# Workaround for bind()
self._sock: Optional[socket.socket] = None
# Server state for start_server() and _incoming()
self._server: Optional[asyncio.AbstractServer] = None
self._accepted: Optional[asyncio.Event] = None
@ -535,34 +531,6 @@ class AsyncProtocol(Generic[T]):
self._reader, self._writer = (reader, writer)
self._accepted.set()
def _bind_hack(self, address: Union[str, Tuple[str, int]]) -> None:
"""
Used to create a socket in advance of accept().
This is a workaround to ensure that we can guarantee timing of
precisely when a socket exists to avoid a connection attempt
bouncing off of nothing.
Python 3.7+ adds a feature to separate the server creation and
listening phases instead, and should be used instead of this
hack.
"""
if isinstance(address, tuple):
family = socket.AF_INET
else:
family = socket.AF_UNIX
sock = socket.socket(family, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
try:
sock.bind(address)
except:
sock.close()
raise
self._sock = sock
@upper_half
async def _do_start_server(self, address: SocketAddrT,
ssl: Optional[SSLContext] = None) -> None:
@ -589,21 +557,19 @@ class AsyncProtocol(Generic[T]):
if isinstance(address, tuple):
coro = asyncio.start_server(
self._incoming,
host=None if self._sock else address[0],
port=None if self._sock else address[1],
host=address[0],
port=address[1],
ssl=ssl,
backlog=1,
limit=self._limit,
sock=self._sock,
)
else:
coro = asyncio.start_unix_server(
self._incoming,
path=None if self._sock else address,
path=address,
ssl=ssl,
backlog=1,
limit=self._limit,
sock=self._sock,
)
# Allow runstate watchers to witness 'CONNECTING' state; some
@ -630,7 +596,6 @@ class AsyncProtocol(Generic[T]):
await self._accepted.wait()
assert self._server is None
self._accepted = None
self._sock = None
self.logger.debug("Connection accepted.")