python/qemu: Change ConsoleSocket to optionally drain socket.
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 <robert.foley@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20200717203041.9867-3-robert.foley@linaro.org> Message-Id: <20200724064509.331-16-alex.bennee@linaro.org>
This commit is contained in:
Robert Foley
Alex Bennée
parent
4b84d87449
commit
80ded8e99d
@ -13,68 +13,75 @@ which can drain a socket and optionally dump the bytes to file.
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# the COPYING file in the top-level directory.
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#
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import asyncore
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import socket
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import threading
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from collections import deque
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import time
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class ConsoleSocket(asyncore.dispatcher):
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class ConsoleSocket(socket.socket):
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"""
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ConsoleSocket represents a socket attached to a char device.
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Drains the socket and places the bytes into an in memory buffer
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for later processing.
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Optionally (if drain==True), drains the socket and places the bytes
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into an in memory buffer for later processing.
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Optionally a file path can be passed in and we will also
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dump the characters to this file for debugging purposes.
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"""
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def __init__(self, address, file=None):
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def __init__(self, address, file=None, drain=False):
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self._recv_timeout_sec = 300
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self._sleep_time = 0.5
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self._buffer = deque()
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self._asyncore_thread = None
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self._sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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self._sock.connect(address)
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socket.socket.__init__(self, socket.AF_UNIX, socket.SOCK_STREAM)
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self.connect(address)
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self._logfile = None
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if file:
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self._logfile = open(file, "w")
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asyncore.dispatcher.__init__(self, sock=self._sock)
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self._open = True
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self._thread_start()
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if drain:
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self._drain_thread = self._thread_start()
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else:
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self._drain_thread = None
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def _drain_fn(self):
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"""Drains the socket and runs while the socket is open."""
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while self._open:
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try:
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self._drain_socket()
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except socket.timeout:
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# The socket is expected to timeout since we set a
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# short timeout to allow the thread to exit when
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# self._open is set to False.
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time.sleep(self._sleep_time)
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def _thread_start(self):
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"""Kick off a thread to wait on the asyncore.loop"""
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if self._asyncore_thread is not None:
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return
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self._asyncore_thread = threading.Thread(target=asyncore.loop,
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kwargs={'timeout':1})
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self._asyncore_thread.daemon = True
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self._asyncore_thread.start()
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def handle_close(self):
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"""redirect close to base class"""
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# Call the base class close, but not self.close() since
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# handle_close() occurs in the context of the thread which
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# self.close() attempts to join.
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asyncore.dispatcher.close(self)
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"""Kick off a thread to drain the socket."""
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# Configure socket to not block and timeout.
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# This allows our drain thread to not block
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# on recieve and exit smoothly.
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socket.socket.setblocking(self, False)
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socket.socket.settimeout(self, 1)
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drain_thread = threading.Thread(target=self._drain_fn)
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drain_thread.daemon = True
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drain_thread.start()
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return drain_thread
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def close(self):
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"""Close the base object and wait for the thread to terminate"""
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if self._open:
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self._open = False
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asyncore.dispatcher.close(self)
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if self._asyncore_thread is not None:
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thread, self._asyncore_thread = self._asyncore_thread, None
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if self._drain_thread is not None:
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thread, self._drain_thread = self._drain_thread, None
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thread.join()
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socket.socket.close(self)
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if self._logfile:
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self._logfile.close()
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self._logfile = None
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def handle_read(self):
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def _drain_socket(self):
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"""process arriving characters into in memory _buffer"""
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data = asyncore.dispatcher.recv(self, 1)
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data = socket.socket.recv(self, 1)
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# latin1 is needed since there are some chars
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# we are receiving that cannot be encoded to utf-8
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# such as 0xe2, 0x80, 0xA6.
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@ -85,27 +92,38 @@ class ConsoleSocket(asyncore.dispatcher):
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for c in string:
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self._buffer.extend(c)
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def recv(self, buffer_size=1):
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def recv(self, bufsize=1):
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"""Return chars from in memory buffer.
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Maintains the same API as socket.socket.recv.
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"""
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if self._drain_thread is None:
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# Not buffering the socket, pass thru to socket.
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return socket.socket.recv(self, bufsize)
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start_time = time.time()
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while len(self._buffer) < buffer_size:
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while len(self._buffer) < bufsize:
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time.sleep(self._sleep_time)
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elapsed_sec = time.time() - start_time
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if elapsed_sec > self._recv_timeout_sec:
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raise socket.timeout
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chars = ''.join([self._buffer.popleft() for i in range(buffer_size)])
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chars = ''.join([self._buffer.popleft() for i in range(bufsize)])
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# We choose to use latin1 to remain consistent with
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# handle_read() and give back the same data as the user would
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# receive if they were reading directly from the
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# socket w/o our intervention.
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return chars.encode("latin1")
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def set_blocking(self):
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"""Maintain compatibility with socket API"""
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pass
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def setblocking(self, value):
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"""When not draining we pass thru to the socket,
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since when draining we control socket blocking.
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"""
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if self._drain_thread is None:
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socket.socket.setblocking(self, value)
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def settimeout(self, seconds):
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"""Set current timeout on recv"""
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self._recv_timeout_sec = seconds
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"""When not draining we pass thru to the socket,
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since when draining we control the timeout.
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"""
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if seconds is not None:
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self._recv_timeout_sec = seconds
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if self._drain_thread is None:
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socket.socket.settimeout(self, seconds)
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@ -23,7 +23,6 @@ import os
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import subprocess
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import shutil
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import signal
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import socket
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import tempfile
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from typing import Optional, Type
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from types import TracebackType
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@ -673,12 +672,8 @@ class QEMUMachine:
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Returns a socket connected to the console
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"""
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if self._console_socket is None:
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if self._drain_console:
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self._console_socket = console_socket.ConsoleSocket(
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self._console_address,
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file=self._console_log_path)
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else:
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self._console_socket = socket.socket(socket.AF_UNIX,
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socket.SOCK_STREAM)
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self._console_socket.connect(self._console_address)
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self._console_socket = console_socket.ConsoleSocket(
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self._console_address,
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file=self._console_log_path,
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drain=self._drain_console)
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return self._console_socket
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