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Diffstat (limited to 'python/qemu/machine.py')
| -rw-r--r-- | python/qemu/machine.py | 520 |
1 files changed, 520 insertions, 0 deletions
diff --git a/python/qemu/machine.py b/python/qemu/machine.py new file mode 100644 index 0000000000..a8a311b035 --- /dev/null +++ b/python/qemu/machine.py @@ -0,0 +1,520 @@ +# QEMU library +# +# Copyright (C) 2015-2016 Red Hat Inc. +# Copyright (C) 2012 IBM Corp. +# +# 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 errno +import logging +import os +import subprocess +import re +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): + 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 |