679 lines
23 KiB
Python
679 lines
23 KiB
Python
"""
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QEMU machine module:
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The machine module primarily provides the QEMUMachine class,
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which provides facilities for managing the lifetime of a QEMU VM.
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"""
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# Copyright (C) 2015-2016 Red Hat Inc.
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# Copyright (C) 2012 IBM Corp.
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#
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# Authors:
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# Fam Zheng <famz@redhat.com>
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#
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# This work is licensed under the terms of the GNU GPL, version 2. See
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# the COPYING file in the top-level directory.
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#
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# Based on qmp.py.
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#
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import errno
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import logging
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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 tempfile
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from typing import Optional, Type
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from types import TracebackType
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from . import console_socket
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from . import qmp
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LOG = logging.getLogger(__name__)
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class QEMUMachineError(Exception):
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"""
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Exception called when an error in QEMUMachine happens.
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"""
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class QEMUMachineAddDeviceError(QEMUMachineError):
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"""
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Exception raised when a request to add a device can not be fulfilled
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The failures are caused by limitations, lack of information or conflicting
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requests on the QEMUMachine methods. This exception does not represent
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failures reported by the QEMU binary itself.
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"""
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class AbnormalShutdown(QEMUMachineError):
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"""
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Exception raised when a graceful shutdown was requested, but not performed.
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"""
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class QEMUMachine:
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"""
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A QEMU VM
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Use this object as a context manager to ensure
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the QEMU process terminates::
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with VM(binary) as vm:
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...
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# vm is guaranteed to be shut down here
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"""
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def __init__(self, binary, args=None, wrapper=None, name=None,
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test_dir="/var/tmp", monitor_address=None,
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socket_scm_helper=None, sock_dir=None,
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drain_console=False, console_log=None):
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'''
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Initialize a QEMUMachine
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@param binary: path to the qemu binary
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@param args: list of extra arguments
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@param wrapper: list of arguments used as prefix to qemu binary
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@param name: prefix for socket and log file names (default: qemu-PID)
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@param test_dir: where to create socket and log file
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@param monitor_address: address for QMP monitor
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@param socket_scm_helper: helper program, required for send_fd_scm()
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@param sock_dir: where to create socket (overrides test_dir for sock)
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@param console_log: (optional) path to console log file
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@param drain_console: (optional) True to drain console socket to buffer
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@note: Qemu process is not started until launch() is used.
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'''
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if args is None:
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args = []
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if wrapper is None:
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wrapper = []
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if name is None:
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name = "qemu-%d" % os.getpid()
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if sock_dir is None:
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sock_dir = test_dir
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self._name = name
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self._monitor_address = monitor_address
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self._vm_monitor = None
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self._qemu_log_path = None
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self._qemu_log_file = None
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self._popen = None
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self._binary = binary
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self._args = list(args) # Force copy args in case we modify them
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self._wrapper = wrapper
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self._events = []
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self._iolog = None
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self._socket_scm_helper = socket_scm_helper
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self._qmp_set = True # Enable QMP monitor by default.
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self._qmp = None
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self._qemu_full_args = None
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self._test_dir = test_dir
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self._temp_dir = None
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self._sock_dir = sock_dir
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self._launched = False
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self._machine = None
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self._console_index = 0
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self._console_set = False
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self._console_device_type = None
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self._console_address = None
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self._console_socket = None
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self._remove_files = []
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self._user_killed = False
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self._console_log_path = console_log
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if self._console_log_path:
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# In order to log the console, buffering needs to be enabled.
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self._drain_console = True
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else:
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self._drain_console = drain_console
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def __enter__(self):
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return self
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def __exit__(self,
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exc_type: Optional[Type[BaseException]],
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exc_val: Optional[BaseException],
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exc_tb: Optional[TracebackType]) -> None:
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self.shutdown()
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def add_monitor_null(self):
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"""
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This can be used to add an unused monitor instance.
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"""
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self._args.append('-monitor')
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self._args.append('null')
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def add_fd(self, fd, fdset, opaque, opts=''):
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"""
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Pass a file descriptor to the VM
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"""
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options = ['fd=%d' % fd,
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'set=%d' % fdset,
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'opaque=%s' % opaque]
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if opts:
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options.append(opts)
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# This did not exist before 3.4, but since then it is
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# mandatory for our purpose
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if hasattr(os, 'set_inheritable'):
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os.set_inheritable(fd, True)
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self._args.append('-add-fd')
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self._args.append(','.join(options))
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return self
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def send_fd_scm(self, fd=None, file_path=None):
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"""
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Send an fd or file_path to socket_scm_helper.
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Exactly one of fd and file_path must be given.
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If it is file_path, the helper will open that file and pass its own fd.
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"""
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# In iotest.py, the qmp should always use unix socket.
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assert self._qmp.is_scm_available()
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if self._socket_scm_helper is None:
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raise QEMUMachineError("No path to socket_scm_helper set")
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if not os.path.exists(self._socket_scm_helper):
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raise QEMUMachineError("%s does not exist" %
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self._socket_scm_helper)
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# This did not exist before 3.4, but since then it is
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# mandatory for our purpose
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if hasattr(os, 'set_inheritable'):
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os.set_inheritable(self._qmp.get_sock_fd(), True)
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if fd is not None:
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os.set_inheritable(fd, True)
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fd_param = ["%s" % self._socket_scm_helper,
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"%d" % self._qmp.get_sock_fd()]
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if file_path is not None:
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assert fd is None
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fd_param.append(file_path)
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else:
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assert fd is not None
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fd_param.append(str(fd))
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devnull = open(os.path.devnull, 'rb')
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proc = subprocess.Popen(
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fd_param, stdin=devnull, stdout=subprocess.PIPE,
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stderr=subprocess.STDOUT, close_fds=False
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)
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output = proc.communicate()[0]
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if output:
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LOG.debug(output)
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return proc.returncode
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@staticmethod
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def _remove_if_exists(path):
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"""
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Remove file object at path if it exists
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"""
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try:
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os.remove(path)
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except OSError as exception:
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if exception.errno == errno.ENOENT:
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return
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raise
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def is_running(self):
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"""Returns true if the VM is running."""
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return self._popen is not None and self._popen.poll() is None
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def exitcode(self):
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"""Returns the exit code if possible, or None."""
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if self._popen is None:
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return None
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return self._popen.poll()
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def get_pid(self):
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"""Returns the PID of the running process, or None."""
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if not self.is_running():
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return None
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return self._popen.pid
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def _load_io_log(self):
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if self._qemu_log_path is not None:
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with open(self._qemu_log_path, "r") as iolog:
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self._iolog = iolog.read()
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def _base_args(self):
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args = ['-display', 'none', '-vga', 'none']
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if self._qmp_set:
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if isinstance(self._monitor_address, tuple):
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moncdev = "socket,id=mon,host=%s,port=%s" % (
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self._monitor_address[0],
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self._monitor_address[1])
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else:
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moncdev = 'socket,id=mon,path=%s' % self._vm_monitor
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args.extend(['-chardev', moncdev, '-mon',
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'chardev=mon,mode=control'])
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if self._machine is not None:
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args.extend(['-machine', self._machine])
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for _ in range(self._console_index):
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args.extend(['-serial', 'null'])
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if self._console_set:
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self._console_address = os.path.join(self._sock_dir,
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self._name + "-console.sock")
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self._remove_files.append(self._console_address)
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chardev = ('socket,id=console,path=%s,server,nowait' %
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self._console_address)
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args.extend(['-chardev', chardev])
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if self._console_device_type is None:
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args.extend(['-serial', 'chardev:console'])
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else:
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device = '%s,chardev=console' % self._console_device_type
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args.extend(['-device', device])
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return args
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def _pre_launch(self):
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self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
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self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
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self._qemu_log_file = open(self._qemu_log_path, 'wb')
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if self._qmp_set:
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if self._monitor_address is not None:
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self._vm_monitor = self._monitor_address
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else:
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self._vm_monitor = os.path.join(self._sock_dir,
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self._name + "-monitor.sock")
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self._remove_files.append(self._vm_monitor)
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self._qmp = qmp.QEMUMonitorProtocol(self._vm_monitor, server=True,
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nickname=self._name)
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def _post_launch(self):
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if self._qmp:
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self._qmp.accept()
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def _post_shutdown(self):
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"""
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Called to cleanup the VM instance after the process has exited.
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May also be called after a failed launch.
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"""
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# Comprehensive reset for the failed launch case:
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self._early_cleanup()
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if self._qmp:
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self._qmp.close()
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self._qmp = None
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self._load_io_log()
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if self._qemu_log_file is not None:
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self._qemu_log_file.close()
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self._qemu_log_file = None
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self._qemu_log_path = None
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if self._temp_dir is not None:
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shutil.rmtree(self._temp_dir)
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self._temp_dir = None
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while len(self._remove_files) > 0:
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self._remove_if_exists(self._remove_files.pop())
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exitcode = self.exitcode()
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if (exitcode is not None and exitcode < 0
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and not (self._user_killed and exitcode == -signal.SIGKILL)):
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msg = 'qemu received signal %i; command: "%s"'
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if self._qemu_full_args:
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command = ' '.join(self._qemu_full_args)
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else:
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command = ''
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LOG.warning(msg, -int(exitcode), command)
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self._user_killed = False
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self._launched = False
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def launch(self):
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"""
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Launch the VM and make sure we cleanup and expose the
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command line/output in case of exception
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"""
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if self._launched:
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raise QEMUMachineError('VM already launched')
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self._iolog = None
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self._qemu_full_args = None
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try:
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self._launch()
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self._launched = True
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except:
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self._post_shutdown()
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LOG.debug('Error launching VM')
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if self._qemu_full_args:
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LOG.debug('Command: %r', ' '.join(self._qemu_full_args))
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if self._iolog:
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LOG.debug('Output: %r', self._iolog)
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raise
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def _launch(self):
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"""
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Launch the VM and establish a QMP connection
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"""
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devnull = open(os.path.devnull, 'rb')
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self._pre_launch()
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self._qemu_full_args = (self._wrapper + [self._binary] +
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self._base_args() + self._args)
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LOG.debug('VM launch command: %r', ' '.join(self._qemu_full_args))
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self._popen = subprocess.Popen(self._qemu_full_args,
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stdin=devnull,
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stdout=self._qemu_log_file,
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stderr=subprocess.STDOUT,
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shell=False,
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close_fds=False)
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self._post_launch()
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def _early_cleanup(self) -> None:
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"""
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Perform any cleanup that needs to happen before the VM exits.
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May be invoked by both soft and hard shutdown in failover scenarios.
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Called additionally by _post_shutdown for comprehensive cleanup.
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"""
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# If we keep the console socket open, we may deadlock waiting
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# for QEMU to exit, while QEMU is waiting for the socket to
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# become writeable.
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if self._console_socket is not None:
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self._console_socket.close()
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self._console_socket = None
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def _hard_shutdown(self) -> None:
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"""
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Perform early cleanup, kill the VM, and wait for it to terminate.
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:raise subprocess.Timeout: When timeout is exceeds 60 seconds
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waiting for the QEMU process to terminate.
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"""
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self._early_cleanup()
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self._popen.kill()
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self._popen.wait(timeout=60)
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def _soft_shutdown(self, timeout: Optional[int],
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has_quit: bool = False) -> None:
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"""
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Perform early cleanup, attempt to gracefully shut down the VM, and wait
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for it to terminate.
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:param timeout: Timeout in seconds for graceful shutdown.
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A value of None is an infinite wait.
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:param has_quit: When True, don't attempt to issue 'quit' QMP command
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:raise ConnectionReset: On QMP communication errors
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:raise subprocess.TimeoutExpired: When timeout is exceeded waiting for
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the QEMU process to terminate.
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"""
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self._early_cleanup()
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if self._qmp is not None:
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if not has_quit:
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# Might raise ConnectionReset
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self._qmp.cmd('quit')
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# May raise subprocess.TimeoutExpired
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self._popen.wait(timeout=timeout)
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def _do_shutdown(self, timeout: Optional[int],
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has_quit: bool = False) -> None:
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"""
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Attempt to shutdown the VM gracefully; fallback to a hard shutdown.
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:param timeout: Timeout in seconds for graceful shutdown.
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A value of None is an infinite wait.
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:param has_quit: When True, don't attempt to issue 'quit' QMP command
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:raise AbnormalShutdown: When the VM could not be shut down gracefully.
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The inner exception will likely be ConnectionReset or
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subprocess.TimeoutExpired. In rare cases, non-graceful termination
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may result in its own exceptions, likely subprocess.TimeoutExpired.
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"""
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try:
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self._soft_shutdown(timeout, has_quit)
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except Exception as exc:
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self._hard_shutdown()
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raise AbnormalShutdown("Could not perform graceful shutdown") \
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from exc
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def shutdown(self, has_quit: bool = False,
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hard: bool = False,
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timeout: Optional[int] = 30) -> None:
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"""
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Terminate the VM (gracefully if possible) and perform cleanup.
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Cleanup will always be performed.
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If the VM has not yet been launched, or shutdown(), wait(), or kill()
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have already been called, this method does nothing.
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:param has_quit: When true, do not attempt to issue 'quit' QMP command.
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:param hard: When true, do not attempt graceful shutdown, and
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suppress the SIGKILL warning log message.
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:param timeout: Optional timeout in seconds for graceful shutdown.
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Default 30 seconds, A `None` value is an infinite wait.
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"""
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if not self._launched:
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return
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try:
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if hard:
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self._user_killed = True
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self._hard_shutdown()
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else:
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self._do_shutdown(timeout, has_quit)
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finally:
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self._post_shutdown()
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def kill(self):
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"""
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Terminate the VM forcefully, wait for it to exit, and perform cleanup.
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"""
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self.shutdown(hard=True)
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def wait(self, timeout: Optional[int] = 30) -> None:
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"""
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Wait for the VM to power off and perform post-shutdown cleanup.
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:param timeout: Optional timeout in seconds. Default 30 seconds.
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A value of `None` is an infinite wait.
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"""
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self.shutdown(has_quit=True, timeout=timeout)
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def set_qmp_monitor(self, enabled=True):
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"""
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Set the QMP monitor.
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@param enabled: if False, qmp monitor options will be removed from
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the base arguments of the resulting QEMU command
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line. Default is True.
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@note: call this function before launch().
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"""
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if enabled:
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self._qmp_set = True
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else:
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self._qmp_set = False
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self._qmp = None
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def qmp(self, cmd, conv_keys=True, **args):
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"""
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Invoke a QMP command and return the response dict
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"""
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qmp_args = dict()
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for key, value in args.items():
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if conv_keys:
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qmp_args[key.replace('_', '-')] = value
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else:
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qmp_args[key] = value
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return self._qmp.cmd(cmd, args=qmp_args)
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def command(self, cmd, conv_keys=True, **args):
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"""
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Invoke a QMP command.
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On success return the response dict.
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On failure raise an exception.
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"""
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reply = self.qmp(cmd, conv_keys, **args)
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if reply is None:
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raise qmp.QMPError("Monitor is closed")
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if "error" in reply:
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raise qmp.QMPResponseError(reply)
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return reply["return"]
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def get_qmp_event(self, wait=False):
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"""
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Poll for one queued QMP events and return it
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"""
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if self._events:
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return self._events.pop(0)
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return self._qmp.pull_event(wait=wait)
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def get_qmp_events(self, wait=False):
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"""
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Poll for queued QMP events and return a list of dicts
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"""
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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, console_index=0):
|
|
"""
|
|
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.
|
|
@param console_index: the index of the console device to use.
|
|
If not zero, the command line will create
|
|
'index - 1' consoles and connect them to
|
|
the 'null' backing character device.
|
|
"""
|
|
self._console_set = True
|
|
self._console_device_type = device_type
|
|
self._console_index = console_index
|
|
|
|
@property
|
|
def console_socket(self):
|
|
"""
|
|
Returns a socket connected to the console
|
|
"""
|
|
if self._console_socket is None:
|
|
self._console_socket = console_socket.ConsoleSocket(
|
|
self._console_address,
|
|
file=self._console_log_path,
|
|
drain=self._drain_console)
|
|
return self._console_socket
|