""" 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 qmp.py. # import errno import logging import os import subprocess import shutil import socket import tempfile from typing import Optional, Type from types import TracebackType from qemu.console_socket import ConsoleSocket 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().__init__(desc) self.reply = reply class QEMUMachine: """ 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, sock_dir=None, drain_console=False, console_log=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() @param sock_dir: where to create socket (overrides test_dir for sock) @param console_log: (optional) path to console log file @param drain_console: (optional) True to drain console socket to buffer @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 = [] self._console_log_path = console_log if self._console_log_path: # In order to log the console, buffering needs to be enabled. self._drain_console = True else: self._drain_console = drain_console def __enter__(self): return self def __exit__(self, exc_type: Optional[Type[BaseException]], exc_val: Optional[BaseException], exc_tb: Optional[TracebackType]) -> None: self.shutdown() def add_monitor_null(self): """ This can be used to add an unused monitor instance. """ 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 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 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): """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 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): args = ['-display', 'none', '-vga', 'none'] if self._qmp_set: 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.extend(['-chardev', moncdev, '-mon', 'chardev=mon,mode=control']) if self._machine is not None: args.extend(['-machine', self._machine]) for _ 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") self._remove_files.append(self._console_address) 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) 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 else: self._vm_monitor = os.path.join(self._sock_dir, self._name + "-monitor.sock") self._remove_files.append(self._vm_monitor) self._qmp = qmp.QEMUMonitorProtocol(self._vm_monitor, server=True, nickname=self._name) def _post_launch(self): if self._qmp: self._qmp.accept() def _post_shutdown(self): if self._qmp: self._qmp.close() self._qmp = None self._load_io_log() 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._temp_dir is not None: shutil.rmtree(self._temp_dir) self._temp_dir = None while len(self._remove_files) > 0: self._remove_if_exists(self._remove_files.pop()) exitcode = self.exitcode() if exitcode is not None and exitcode < 0: msg = 'qemu received signal %i; command: "%s"' if self._qemu_full_args: command = ' '.join(self._qemu_full_args) else: command = '' LOG.warning(msg, -int(exitcode), command) self._launched = False 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 _early_cleanup(self) -> None: """ Perform any cleanup that needs to happen before the VM exits. """ # 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.close() self._console_socket = None def wait(self): """ Wait for the VM to power off """ self._early_cleanup() self._popen.wait() self._post_shutdown() def shutdown(self, has_quit=False, hard=False): """ Terminate the VM and clean up """ self._early_cleanup() if self.is_running(): if hard: self._popen.kill() elif self._qmp: try: if not has_quit: self._qmp.cmd('quit') self._popen.wait(timeout=3) except: self._popen.kill() self._popen.wait() self._post_shutdown() def kill(self): self.shutdown(hard=True) 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 else: 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 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 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) 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: if self._drain_console: self._console_socket = ConsoleSocket(self._console_address, file=self._console_log_path) else: self._console_socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) self._console_socket.connect(self._console_address) return self._console_socket