python/qemu: split QEMUMachine out from underneath __init__.py (abf0bf99) · Commits · SUMMER2020 / students / proj-2021291

python/qemu/init.py

+1 −501

Original line number	Diff line number	Diff line
		@@ -12,17 +12,11 @@
		# Based on qmp.py.
		#

		import errno
		import logging
		import os
		import subprocess
		import re
		import shutil
		import socket
		import tempfile

		from . import qmp

		from . import machine

		LOG = logging.getLogger(__name__)

		@@ -39,497 +33,3 @@ def kvm_available(target_arch=None):
		if target_arch != ADDITIONAL_ARCHES.get(host_arch):
		return False
		return os.access("/dev/kvm", os.R_OK \| os.W_OK)


		class QEMUMachineError(Exception):
		"""
		Exception called when an error in QEMUMachine happens.
		"""


		class QEMUMachineAddDeviceError(QEMUMachineError):
		"""
		Exception raised when a request to add a device can not be fulfilled

		The failures are caused by limitations, lack of information or conflicting
		requests on the QEMUMachine methods. This exception does not represent
		failures reported by the QEMU binary itself.
		"""

		class MonitorResponseError(qmp.QMPError):
		"""
		Represents erroneous QMP monitor reply
		"""
		def __init__(self, reply):
		try:
		desc = reply["error"]["desc"]
		except KeyError:
		desc = reply
		super(MonitorResponseError, self).__init__(desc)
		self.reply = reply


		class QEMUMachine(object):
		"""
		A QEMU VM

		Use this object as a context manager to ensure the QEMU process terminates::

		with VM(binary) as vm:
		...
		# vm is guaranteed to be shut down here
		"""

		def __init__(self, binary, args=None, wrapper=None, name=None,
		test_dir="/var/tmp", monitor_address=None,
		socket_scm_helper=None):
		'''
		Initialize a QEMUMachine

		@param binary: path to the qemu binary
		@param args: list of extra arguments
		@param wrapper: list of arguments used as prefix to qemu binary
		@param name: prefix for socket and log file names (default: qemu-PID)
		@param test_dir: where to create socket and log file
		@param monitor_address: address for QMP monitor
		@param socket_scm_helper: helper program, required for send_fd_scm()
		@note: Qemu process is not started until launch() is used.
		'''
		if args is None:
		args = []
		if wrapper is None:
		wrapper = []
		if name is None:
		name = "qemu-%d" % os.getpid()
		self._name = name
		self._monitor_address = monitor_address
		self._vm_monitor = None
		self._qemu_log_path = None
		self._qemu_log_file = None
		self._popen = None
		self._binary = binary
		self._args = list(args) # Force copy args in case we modify them
		self._wrapper = wrapper
		self._events = []
		self._iolog = None
		self._socket_scm_helper = socket_scm_helper
		self._qmp = None
		self._qemu_full_args = None
		self._test_dir = test_dir
		self._temp_dir = None
		self._launched = False
		self._machine = None
		self._console_set = False
		self._console_device_type = None
		self._console_address = None
		self._console_socket = None

		# just in case logging wasn't configured by the main script:
		logging.basicConfig()

		def __enter__(self):
		return self

		def __exit__(self, exc_type, exc_val, exc_tb):
		self.shutdown()
		return False

		# This can be used to add an unused monitor instance.
		def add_monitor_null(self):
		self._args.append('-monitor')
		self._args.append('null')

		def add_fd(self, fd, fdset, opaque, opts=''):
		"""
		Pass a file descriptor to the VM
		"""
		options = ['fd=%d' % fd,
		'set=%d' % fdset,
		'opaque=%s' % opaque]
		if opts:
		options.append(opts)

		# This did not exist before 3.4, but since then it is
		# mandatory for our purpose
		if hasattr(os, 'set_inheritable'):
		os.set_inheritable(fd, True)

		self._args.append('-add-fd')
		self._args.append(','.join(options))
		return self

		# Exactly one of fd and file_path must be given.
		# (If it is file_path, the helper will open that file and pass its
		# own fd)
		def send_fd_scm(self, fd=None, file_path=None):
		# In iotest.py, the qmp should always use unix socket.
		assert self._qmp.is_scm_available()
		if self._socket_scm_helper is None:
		raise QEMUMachineError("No path to socket_scm_helper set")
		if not os.path.exists(self._socket_scm_helper):
		raise QEMUMachineError("%s does not exist" %
		self._socket_scm_helper)

		# This did not exist before 3.4, but since then it is
		# mandatory for our purpose
		if hasattr(os, 'set_inheritable'):
		os.set_inheritable(self._qmp.get_sock_fd(), True)
		if fd is not None:
		os.set_inheritable(fd, True)

		fd_param = ["%s" % self._socket_scm_helper,
		"%d" % self._qmp.get_sock_fd()]

		if file_path is not None:
		assert fd is None
		fd_param.append(file_path)
		else:
		assert fd is not None
		fd_param.append(str(fd))

		devnull = open(os.path.devnull, 'rb')
		proc = subprocess.Popen(fd_param, stdin=devnull, stdout=subprocess.PIPE,
		stderr=subprocess.STDOUT, close_fds=False)
		output = proc.communicate()[0]
		if output:
		LOG.debug(output)

		return proc.returncode

		@staticmethod
		def _remove_if_exists(path):
		"""
		Remove file object at path if it exists
		"""
		try:
		os.remove(path)
		except OSError as exception:
		if exception.errno == errno.ENOENT:
		return
		raise

		def is_running(self):
		return self._popen is not None and self._popen.poll() is None

		def exitcode(self):
		if self._popen is None:
		return None
		return self._popen.poll()

		def get_pid(self):
		if not self.is_running():
		return None
		return self._popen.pid

		def _load_io_log(self):
		if self._qemu_log_path is not None:
		with open(self._qemu_log_path, "r") as iolog:
		self._iolog = iolog.read()

		def _base_args(self):
		if isinstance(self._monitor_address, tuple):
		moncdev = "socket,id=mon,host=%s,port=%s" % (
		self._monitor_address[0],
		self._monitor_address[1])
		else:
		moncdev = 'socket,id=mon,path=%s' % self._vm_monitor
		args = ['-chardev', moncdev,
		'-mon', 'chardev=mon,mode=control',
		'-display', 'none', '-vga', 'none']
		if self._machine is not None:
		args.extend(['-machine', self._machine])
		if self._console_set:
		self._console_address = os.path.join(self._temp_dir,
		self._name + "-console.sock")
		chardev = ('socket,id=console,path=%s,server,nowait' %
		self._console_address)
		args.extend(['-chardev', chardev])
		if self._console_device_type is None:
		args.extend(['-serial', 'chardev:console'])
		else:
		device = '%s,chardev=console' % self._console_device_type
		args.extend(['-device', device])
		return args

		def _pre_launch(self):
		self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
		if self._monitor_address is not None:
		self._vm_monitor = self._monitor_address
		else:
		self._vm_monitor = os.path.join(self._temp_dir,
		self._name + "-monitor.sock")
		self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
		self._qemu_log_file = open(self._qemu_log_path, 'wb')

		self._qmp = qmp.QEMUMonitorProtocol(self._vm_monitor,
		server=True)

		def _post_launch(self):
		self._qmp.accept()

		def _post_shutdown(self):
		if self._qemu_log_file is not None:
		self._qemu_log_file.close()
		self._qemu_log_file = None

		self._qemu_log_path = None

		if self._console_socket is not None:
		self._console_socket.close()
		self._console_socket = None

		if self._temp_dir is not None:
		shutil.rmtree(self._temp_dir)
		self._temp_dir = None

		def launch(self):
		"""
		Launch the VM and make sure we cleanup and expose the
		command line/output in case of exception
		"""

		if self._launched:
		raise QEMUMachineError('VM already launched')

		self._iolog = None
		self._qemu_full_args = None
		try:
		self._launch()
		self._launched = True
		except:
		self.shutdown()

		LOG.debug('Error launching VM')
		if self._qemu_full_args:
		LOG.debug('Command: %r', ' '.join(self._qemu_full_args))
		if self._iolog:
		LOG.debug('Output: %r', self._iolog)
		raise

		def _launch(self):
		"""
		Launch the VM and establish a QMP connection
		"""
		devnull = open(os.path.devnull, 'rb')
		self._pre_launch()
		self._qemu_full_args = (self._wrapper + [self._binary] +
		self._base_args() + self._args)
		LOG.debug('VM launch command: %r', ' '.join(self._qemu_full_args))
		self._popen = subprocess.Popen(self._qemu_full_args,
		stdin=devnull,
		stdout=self._qemu_log_file,
		stderr=subprocess.STDOUT,
		shell=False,
		close_fds=False)
		self._post_launch()

		def wait(self):
		"""
		Wait for the VM to power off
		"""
		self._popen.wait()
		self._qmp.close()
		self._load_io_log()
		self._post_shutdown()

		def shutdown(self):
		"""
		Terminate the VM and clean up
		"""
		if self.is_running():
		try:
		self._qmp.cmd('quit')
		self._qmp.close()
		except:
		self._popen.kill()
		self._popen.wait()

		self._load_io_log()
		self._post_shutdown()

		exitcode = self.exitcode()
		if exitcode is not None and exitcode < 0:
		msg = 'qemu received signal %i: %s'
		if self._qemu_full_args:
		command = ' '.join(self._qemu_full_args)
		else:
		command = ''
		LOG.warn(msg, -exitcode, command)

		self._launched = False

		def qmp(self, cmd, conv_keys=True, **args):
		"""
		Invoke a QMP command and return the response dict
		"""
		qmp_args = dict()
		for key, value in args.items():
		if conv_keys:
		qmp_args[key.replace('_', '-')] = value
		else:
		qmp_args[key] = value

		return self._qmp.cmd(cmd, args=qmp_args)

		def command(self, cmd, conv_keys=True, **args):
		"""
		Invoke a QMP command.
		On success return the response dict.
		On failure raise an exception.
		"""
		reply = self.qmp(cmd, conv_keys, **args)
		if reply is None:
		raise qmp.QMPError("Monitor is closed")
		if "error" in reply:
		raise MonitorResponseError(reply)
		return reply["return"]

		def get_qmp_event(self, wait=False):
		"""
		Poll for one queued QMP events and return it
		"""
		if len(self._events) > 0:
		return self._events.pop(0)
		return self._qmp.pull_event(wait=wait)

		def get_qmp_events(self, wait=False):
		"""
		Poll for queued QMP events and return a list of dicts
		"""
		events = self._qmp.get_events(wait=wait)
		events.extend(self._events)
		del self._events[:]
		self._qmp.clear_events()
		return events

		@staticmethod
		def event_match(event, match=None):
		"""
		Check if an event matches optional match criteria.

		The match criteria takes the form of a matching subdict. The event is
		checked to be a superset of the subdict, recursively, with matching
		values whenever the subdict values are not None.

		This has a limitation that you cannot explicitly check for None values.

		Examples, with the subdict queries on the left:
		- None matches any object.
		- {"foo": None} matches {"foo": {"bar": 1}}
		- {"foo": None} matches {"foo": 5}
		- {"foo": {"abc": None}} does not match {"foo": {"bar": 1}}
		- {"foo": {"rab": 2}} matches {"foo": {"bar": 1, "rab": 2}}
		"""
		if match is None:
		return True

		try:
		for key in match:
		if key in event:
		if not QEMUMachine.event_match(event[key], match[key]):
		return False
		else:
		return False
		return True
		except TypeError:
		# either match or event wasn't iterable (not a dict)
		return match == event

		def event_wait(self, name, timeout=60.0, match=None):
		"""
		event_wait waits for and returns a named event from QMP with a timeout.

		name: The event to wait for.
		timeout: QEMUMonitorProtocol.pull_event timeout parameter.
		match: Optional match criteria. See event_match for details.
		"""
		return self.events_wait([(name, match)], timeout)

		def events_wait(self, events, timeout=60.0):
		"""
		events_wait waits for and returns a named event from QMP with a timeout.

		events: a sequence of (name, match_criteria) tuples.
		The match criteria are optional and may be None.
		See event_match for details.
		timeout: QEMUMonitorProtocol.pull_event timeout parameter.
		"""
		def _match(event):
		for name, match in events:
		if (event['event'] == name and
		self.event_match(event, match)):
		return True
		return False

		# Search cached events
		for event in self._events:
		if _match(event):
		self._events.remove(event)
		return event

		# Poll for new events
		while True:
		event = self._qmp.pull_event(wait=timeout)
		if _match(event):
		return event
		self._events.append(event)

		return None

		def get_log(self):
		"""
		After self.shutdown or failed qemu execution, this returns the output
		of the qemu process.
		"""
		return self._iolog

		def add_args(self, *args):
		"""
		Adds to the list of extra arguments to be given to the QEMU binary
		"""
		self._args.extend(args)

		def set_machine(self, machine_type):
		"""
		Sets the machine type

		If set, the machine type will be added to the base arguments
		of the resulting QEMU command line.
		"""
		self._machine = machine_type

		def set_console(self, device_type=None):
		"""
		Sets the device type for a console device

		If set, the console device and a backing character device will
		be added to the base arguments of the resulting QEMU command
		line.

		This is a convenience method that will either use the provided
		device type, or default to a "-serial chardev:console" command
		line argument.

		The actual setting of command line arguments will be be done at
		machine launch time, as it depends on the temporary directory
		to be created.

		@param device_type: the device type, such as "isa-serial". If
		None is given (the default value) a "-serial
		chardev:console" command line argument will
		be used instead, resorting to the machine's
		default device type.
		"""
		self._console_set = True
		self._console_device_type = device_type

		@property
		def console_socket(self):
		"""
		Returns a socket connected to the console
		"""
		if self._console_socket is None:
		self._console_socket = socket.socket(socket.AF_UNIX,
		socket.SOCK_STREAM)
		self._console_socket.connect(self._console_address)
		return self._console_socket

python/qemu/machine.py

0 → 100644

+520 −0

File added.

Preview size limit exceeded, changes collapsed.

python/qemu/qtest.py

+1 −1

Original line number	Diff line number	Diff line
		@@ -14,7 +14,7 @@
		import socket
		import os

		from . import QEMUMachine
		from .machine import QEMUMachine


		class QEMUQtestProtocol(object):

scripts/device-crash-test

+1 −1

Original line number	Diff line number	Diff line
		@@ -36,7 +36,7 @@ import argparse
		from itertools import chain

		sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'python'))
		from qemu import QEMUMachine
		from qemu.machine import QEMUMachine

		logger = logging.getLogger('device-crash-test')
		dbg = logger.debug

scripts/render_block_graph.py

+1 −1

Original line number	Diff line number	Diff line
		@@ -25,7 +25,7 @@ import json
		from graphviz import Digraph

		sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'python'))
		from qemu import MonitorResponseError
		from qemu.machine import MonitorResponseError


		def perm(arr):