blob: b9a98e2c862767a3e639fbb359cf9fa9b7b2d221 [file] [log] [blame]
QEMU machine module:
The machine module primarily provides the QEMUMachine class,
which provides facilities for managing the lifetime of a QEMU VM.
# Copyright (C) 2015-2016 Red Hat Inc.
# Copyright (C) 2012 IBM Corp.
# Authors:
# Fam Zheng <>
# This work is licensed under the terms of the GNU GPL, version 2. See
# the COPYING file in the top-level directory.
# Based on
import errno
import logging
import os
import subprocess
import shutil
import socket
import tempfile
from . import qmp
LOG = logging.getLogger(__name__)
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):
desc = reply["error"]["desc"]
except KeyError:
desc = reply
super(MonitorResponseError, self).__init__(desc)
self.reply = reply
class QEMUMachine(object):
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, sock_dir=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()
if sock_dir is None:
sock_dir = test_dir
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_set = True # Enable QMP monitor by default.
self._qmp = None
self._qemu_full_args = None
self._test_dir = test_dir
self._temp_dir = None
self._sock_dir = sock_dir
self._launched = False
self._machine = None
self._console_index = 0
self._console_set = False
self._console_device_type = None
self._console_address = None
self._console_socket = None
self._remove_files = []
# just in case logging wasn't configured by the main script:
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
return False
def add_monitor_null(self):
This can be used to add an unused monitor instance.
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:
# 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)
return self
def send_fd_scm(self, fd=None, file_path=None):
Send an fd or file_path to socket_scm_helper.
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.
# In, 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" %
# 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
assert fd is not None
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:
return proc.returncode
def _remove_if_exists(path):
Remove file object at path if it exists
except OSError as exception:
if exception.errno == errno.ENOENT:
def is_running(self):
"""Returns true if the VM is running."""
return self._popen is not None and self._popen.poll() is None
def exitcode(self):
"""Returns the exit code if possible, or None."""
if self._popen is None:
return None
return self._popen.poll()
def get_pid(self):
"""Returns the PID of the running process, or None."""
if not self.is_running():
return None
def _load_io_log(self):
if self._qemu_log_path is not None:
with open(self._qemu_log_path, "r") as iolog:
self._iolog =
def _base_args(self):
args = ['-display', 'none', '-vga', 'none']
if self._qmp_set:
if isinstance(self._monitor_address, tuple):
moncdev = "socket,id=mon,host=%s,port=%s" % (
moncdev = 'socket,id=mon,path=%s' % self._vm_monitor
args.extend(['-chardev', moncdev, '-mon',
if self._machine is not None:
args.extend(['-machine', self._machine])
for i in range(self._console_index):
args.extend(['-serial', 'null'])
if self._console_set:
self._console_address = os.path.join(self._sock_dir,
self._name + "-console.sock")
chardev = ('socket,id=console,path=%s,server,nowait' %
args.extend(['-chardev', chardev])
if self._console_device_type is None:
args.extend(['-serial', 'chardev:console'])
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)
self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
self._qemu_log_file = open(self._qemu_log_path, 'wb')
if self._qmp_set:
if self._monitor_address is not None:
self._vm_monitor = self._monitor_address
self._vm_monitor = os.path.join(self._sock_dir,
self._name + "-monitor.sock")
self._qmp = qmp.QEMUMonitorProtocol(self._vm_monitor, server=True,
def _post_launch(self):
if self._qmp:
def _post_shutdown(self):
if self._qemu_log_file is not None:
self._qemu_log_file = None
self._qemu_log_path = None
if self._temp_dir is not None:
self._temp_dir = None
while len(self._remove_files) > 0:
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
self._launched = True
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)
def _launch(self):
Launch the VM and establish a QMP connection
devnull = open(os.path.devnull, 'rb')
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,
def wait(self):
Wait for the VM to power off
if self._qmp:
def shutdown(self, has_quit=False):
Terminate the VM and clean up
# If we keep the console socket open, we may deadlock waiting
# for QEMU to exit, while QEMU is waiting for the socket to
# become writeable.
if self._console_socket is not None:
self._console_socket = None
if self.is_running():
if self._qmp:
if not has_quit:
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)
command = ''
LOG.warning(msg, -exitcode, command)
self._launched = False
def set_qmp_monitor(self, enabled=True):
Set the QMP monitor.
@param enabled: if False, qmp monitor options will be removed from
the base arguments of the resulting QEMU command
line. Default is True.
@note: call this function before launch().
if enabled:
self._qmp_set = True
self._qmp_set = False
self._qmp = None
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
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 self._events:
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)
del self._events[:]
return events
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
for key in match:
if key in event:
if not QEMUMachine.event_match(event[key], match[key]):
return False
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):
return event
# Poll for new events
while True:
event = self._qmp.pull_event(wait=timeout)
if _match(event):
return 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
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
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
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,
return self._console_socket