xemu/python/qemu/qtest.py
John Snow c95dddce49 python/qemu/qtest: Check before accessing _qtest
It can be None; so add assertions or exceptions where appropriate to
guard the access accordingly.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200514055403.18902-30-jsnow@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2020-05-31 18:25:31 +02:00

143 lines
4.0 KiB
Python

"""
QEMU qtest library
qtest offers the QEMUQtestProtocol and QEMUQTestMachine classes, which
offer a connection to QEMU's qtest protocol socket, and a qtest-enabled
subclass of QEMUMachine, respectively.
"""
# Copyright (C) 2015 Red Hat Inc.
#
# Authors:
# Fam Zheng <famz@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2. See
# the COPYING file in the top-level directory.
#
# Based on qmp.py.
#
import socket
import os
from typing import Optional, TextIO
from .machine import QEMUMachine
class QEMUQtestProtocol:
"""
QEMUQtestProtocol implements a connection to a qtest socket.
:param address: QEMU address, can be either a unix socket path (string)
or a tuple in the form ( address, port ) for a TCP
connection
:param server: server mode, listens on the socket (bool)
:raise socket.error: on socket connection errors
.. note::
No conection is estabalished by __init__(), this is done
by the connect() or accept() methods.
"""
def __init__(self, address, server=False):
self._address = address
self._sock = self._get_sock()
self._sockfile: Optional[TextIO] = None
if server:
self._sock.bind(self._address)
self._sock.listen(1)
def _get_sock(self):
if isinstance(self._address, tuple):
family = socket.AF_INET
else:
family = socket.AF_UNIX
return socket.socket(family, socket.SOCK_STREAM)
def connect(self):
"""
Connect to the qtest socket.
@raise socket.error on socket connection errors
"""
self._sock.connect(self._address)
self._sockfile = self._sock.makefile(mode='r')
def accept(self):
"""
Await connection from QEMU.
@raise socket.error on socket connection errors
"""
self._sock, _ = self._sock.accept()
self._sockfile = self._sock.makefile(mode='r')
def cmd(self, qtest_cmd):
"""
Send a qtest command on the wire.
@param qtest_cmd: qtest command text to be sent
"""
assert self._sockfile is not None
self._sock.sendall((qtest_cmd + "\n").encode('utf-8'))
resp = self._sockfile.readline()
return resp
def close(self):
"""Close this socket."""
self._sock.close()
if self._sockfile:
self._sockfile.close()
self._sockfile = None
def settimeout(self, timeout):
"""Set a timeout, in seconds."""
self._sock.settimeout(timeout)
class QEMUQtestMachine(QEMUMachine):
"""
A QEMU VM, with a qtest socket available.
"""
def __init__(self, binary, args=None, name=None, test_dir="/var/tmp",
socket_scm_helper=None, sock_dir=None):
if name is None:
name = "qemu-%d" % os.getpid()
if sock_dir is None:
sock_dir = test_dir
super().__init__(binary, args, name=name, test_dir=test_dir,
socket_scm_helper=socket_scm_helper,
sock_dir=sock_dir)
self._qtest = None
self._qtest_path = os.path.join(sock_dir, name + "-qtest.sock")
def _base_args(self):
args = super()._base_args()
args.extend(['-qtest', 'unix:path=' + self._qtest_path,
'-accel', 'qtest'])
return args
def _pre_launch(self):
super()._pre_launch()
self._qtest = QEMUQtestProtocol(self._qtest_path, server=True)
def _post_launch(self) -> None:
assert self._qtest is not None
super()._post_launch()
self._qtest.accept()
def _post_shutdown(self):
super()._post_shutdown()
self._remove_if_exists(self._qtest_path)
def qtest(self, cmd: str) -> str:
"""
Send a qtest command to the guest.
:param cmd: qtest command to send
:return: qtest server response
"""
if self._qtest is None:
raise RuntimeError("qtest socket not available")
return self._qtest.cmd(cmd)