From 80ded8e99d9fc44c206f6b2fae6638df7dcf9305 Mon Sep 17 00:00:00 2001 From: Robert Foley Date: Fri, 24 Jul 2020 07:45:08 +0100 Subject: [PATCH] python/qemu: Change ConsoleSocket to optionally drain socket. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The primary purpose of this change is to clean up machine.py's console_socket property to return a single type, a ConsoleSocket. ConsoleSocket now derives from a socket, which means that in the default case (of not draining), machine.py will see the same behavior as it did prior to ConsoleSocket. Signed-off-by: Robert Foley Signed-off-by: Alex Bennée Message-Id: <20200717203041.9867-3-robert.foley@linaro.org> Message-Id: <20200724064509.331-16-alex.bennee@linaro.org> --- python/qemu/console_socket.py | 92 +++++++++++++++++++++-------------- python/qemu/machine.py | 13 ++--- 2 files changed, 59 insertions(+), 46 deletions(-) diff --git a/python/qemu/console_socket.py b/python/qemu/console_socket.py index 09986bc215..70869fbbdc 100644 --- a/python/qemu/console_socket.py +++ b/python/qemu/console_socket.py @@ -13,68 +13,75 @@ which can drain a socket and optionally dump the bytes to file. # the COPYING file in the top-level directory. # -import asyncore import socket import threading from collections import deque import time -class ConsoleSocket(asyncore.dispatcher): +class ConsoleSocket(socket.socket): """ ConsoleSocket represents a socket attached to a char device. - Drains the socket and places the bytes into an in memory buffer - for later processing. + 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, file=None): + def __init__(self, address, file=None, drain=False): self._recv_timeout_sec = 300 self._sleep_time = 0.5 self._buffer = deque() - self._asyncore_thread = None - self._sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) - self._sock.connect(address) + socket.socket.__init__(self, socket.AF_UNIX, socket.SOCK_STREAM) + self.connect(address) self._logfile = None if file: self._logfile = open(file, "w") - asyncore.dispatcher.__init__(self, sock=self._sock) self._open = True - self._thread_start() + if drain: + self._drain_thread = self._thread_start() + else: + self._drain_thread = None + + def _drain_fn(self): + """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): - """Kick off a thread to wait on the asyncore.loop""" - if self._asyncore_thread is not None: - return - self._asyncore_thread = threading.Thread(target=asyncore.loop, - kwargs={'timeout':1}) - self._asyncore_thread.daemon = True - self._asyncore_thread.start() - - def handle_close(self): - """redirect close to base class""" - # Call the base class close, but not self.close() since - # handle_close() occurs in the context of the thread which - # self.close() attempts to join. - asyncore.dispatcher.close(self) + """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): """Close the base object and wait for the thread to terminate""" if self._open: self._open = False - asyncore.dispatcher.close(self) - if self._asyncore_thread is not None: - thread, self._asyncore_thread = self._asyncore_thread, None + 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 handle_read(self): + def _drain_socket(self): """process arriving characters into in memory _buffer""" - data = asyncore.dispatcher.recv(self, 1) + data = socket.socket.recv(self, 1) # latin1 is needed since there are some chars # we are receiving that cannot be encoded to utf-8 # such as 0xe2, 0x80, 0xA6. @@ -85,27 +92,38 @@ class ConsoleSocket(asyncore.dispatcher): for c in string: self._buffer.extend(c) - def recv(self, buffer_size=1): + def recv(self, bufsize=1): """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) start_time = time.time() - while len(self._buffer) < buffer_size: + 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 - chars = ''.join([self._buffer.popleft() for i in range(buffer_size)]) + chars = ''.join([self._buffer.popleft() for i in range(bufsize)]) # We choose to use latin1 to remain consistent with # handle_read() and give back the same data as the user would # receive if they were reading directly from the # socket w/o our intervention. return chars.encode("latin1") - def set_blocking(self): - """Maintain compatibility with socket API""" - pass + def setblocking(self, value): + """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, seconds): - """Set current timeout on recv""" - self._recv_timeout_sec = seconds + """When not draining we pass thru to the socket, + since when draining we control the timeout. + """ + if seconds is not None: + self._recv_timeout_sec = seconds + if self._drain_thread is None: + socket.socket.settimeout(self, seconds) diff --git a/python/qemu/machine.py b/python/qemu/machine.py index a09768e9f9..82f3731fc3 100644 --- a/python/qemu/machine.py +++ b/python/qemu/machine.py @@ -23,7 +23,6 @@ import os import subprocess import shutil import signal -import socket import tempfile from typing import Optional, Type from types import TracebackType @@ -673,12 +672,8 @@ class QEMUMachine: Returns a socket connected to the console """ if self._console_socket is None: - if self._drain_console: - self._console_socket = console_socket.ConsoleSocket( - self._console_address, - file=self._console_log_path) - else: - self._console_socket = socket.socket(socket.AF_UNIX, - socket.SOCK_STREAM) - self._console_socket.connect(self._console_address) + self._console_socket = console_socket.ConsoleSocket( + self._console_address, + file=self._console_log_path, + drain=self._drain_console) return self._console_socket