qemu-e2k/python/qemu/machine/console_socket.py
John Snow beb6b57b3b python: create qemu packages
move python/qemu/*.py to python/qemu/[machine, qmp, utils]/*.py and
update import directives across the tree.

This is done to create a PEP420 namespace package, in which we may
create subpackages. To do this, the namespace directory ("qemu") should
not have any modules in it. Those files will go into new 'machine',
'qmp' and 'utils' subpackages instead.

Implement machine/__init__.py making the top-level classes and functions
from its various modules available directly inside the package. Change
qmp.py to qmp/__init__.py similarly, such that all of the useful QMP
library classes are available directly from "qemu.qmp" instead of
"qemu.qmp.qmp".

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-10-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-01 16:21:21 -04:00

130 lines
4.6 KiB
Python

"""
QEMU Console Socket Module:
This python module implements a ConsoleSocket object,
which can drain a socket and optionally dump the bytes to file.
"""
# Copyright 2020 Linaro
#
# Authors:
# Robert Foley <robert.foley@linaro.org>
#
# This code is licensed under the GPL version 2 or later. See
# the COPYING file in the top-level directory.
#
from collections import deque
import socket
import threading
import time
from typing import Deque, Optional
class ConsoleSocket(socket.socket):
"""
ConsoleSocket represents a socket attached to a char device.
Optionally (if drain==True), drains the socket and places the bytes
into an in memory buffer for later processing.
Optionally a file path can be passed in and we will also
dump the characters to this file for debugging purposes.
"""
def __init__(self, address: str, file: Optional[str] = None,
drain: bool = False):
self._recv_timeout_sec = 300.0
self._sleep_time = 0.5
self._buffer: Deque[int] = deque()
socket.socket.__init__(self, socket.AF_UNIX, socket.SOCK_STREAM)
self.connect(address)
self._logfile = None
if file:
# pylint: disable=consider-using-with
self._logfile = open(file, "bw")
self._open = True
self._drain_thread = None
if drain:
self._drain_thread = self._thread_start()
def __repr__(self) -> str:
tmp = super().__repr__()
tmp = tmp.rstrip(">")
tmp = "%s, logfile=%s, drain_thread=%s>" % (tmp, self._logfile,
self._drain_thread)
return tmp
def _drain_fn(self) -> None:
"""Drains the socket and runs while the socket is open."""
while self._open:
try:
self._drain_socket()
except socket.timeout:
# The socket is expected to timeout since we set a
# short timeout to allow the thread to exit when
# self._open is set to False.
time.sleep(self._sleep_time)
def _thread_start(self) -> threading.Thread:
"""Kick off a thread to drain the socket."""
# Configure socket to not block and timeout.
# This allows our drain thread to not block
# on recieve and exit smoothly.
socket.socket.setblocking(self, False)
socket.socket.settimeout(self, 1)
drain_thread = threading.Thread(target=self._drain_fn)
drain_thread.daemon = True
drain_thread.start()
return drain_thread
def close(self) -> None:
"""Close the base object and wait for the thread to terminate"""
if self._open:
self._open = False
if self._drain_thread is not None:
thread, self._drain_thread = self._drain_thread, None
thread.join()
socket.socket.close(self)
if self._logfile:
self._logfile.close()
self._logfile = None
def _drain_socket(self) -> None:
"""process arriving characters into in memory _buffer"""
data = socket.socket.recv(self, 1)
if self._logfile:
self._logfile.write(data)
self._logfile.flush()
self._buffer.extend(data)
def recv(self, bufsize: int = 1, flags: int = 0) -> bytes:
"""Return chars from in memory buffer.
Maintains the same API as socket.socket.recv.
"""
if self._drain_thread is None:
# Not buffering the socket, pass thru to socket.
return socket.socket.recv(self, bufsize, flags)
assert not flags, "Cannot pass flags to recv() in drained mode"
start_time = time.time()
while len(self._buffer) < bufsize:
time.sleep(self._sleep_time)
elapsed_sec = time.time() - start_time
if elapsed_sec > self._recv_timeout_sec:
raise socket.timeout
return bytes((self._buffer.popleft() for i in range(bufsize)))
def setblocking(self, value: bool) -> None:
"""When not draining we pass thru to the socket,
since when draining we control socket blocking.
"""
if self._drain_thread is None:
socket.socket.setblocking(self, value)
def settimeout(self, value: Optional[float]) -> None:
"""When not draining we pass thru to the socket,
since when draining we control the timeout.
"""
if value is not None:
self._recv_timeout_sec = value
if self._drain_thread is None:
socket.socket.settimeout(self, value)