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Diffstat (limited to 'python/qemu/qmp/legacy.py')
| -rw-r--r-- | python/qemu/qmp/legacy.py | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/python/qemu/qmp/legacy.py b/python/qemu/qmp/legacy.py new file mode 100644 index 0000000000..a8629b44df --- /dev/null +++ b/python/qemu/qmp/legacy.py @@ -0,0 +1,317 @@ +""" +(Legacy) Sync QMP Wrapper + +This module provides the `QEMUMonitorProtocol` class, which is a +synchronous wrapper around `QMPClient`. + +Its design closely resembles that of the original QEMUMonitorProtocol +class, originally written by Luiz Capitulino. It is provided here for +compatibility with scripts inside the QEMU source tree that expect the +old interface. +""" + +# +# Copyright (C) 2009-2022 Red Hat Inc. +# +# Authors: +# Luiz Capitulino <lcapitulino@redhat.com> +# John Snow <jsnow@redhat.com> +# +# This work is licensed under the terms of the GNU GPL, version 2. See +# the COPYING file in the top-level directory. +# + +import asyncio +from types import TracebackType +from typing import ( + Any, + Awaitable, + Dict, + List, + Optional, + Type, + TypeVar, + Union, +) + +from .error import QMPError +from .protocol import Runstate, SocketAddrT +from .qmp_client import QMPClient + + +#: QMPMessage is an entire QMP message of any kind. +QMPMessage = Dict[str, Any] + +#: QMPReturnValue is the 'return' value of a command. +QMPReturnValue = object + +#: QMPObject is any object in a QMP message. +QMPObject = Dict[str, object] + +# QMPMessage can be outgoing commands or incoming events/returns. +# QMPReturnValue is usually a dict/json object, but due to QAPI's +# 'returns-whitelist', it can actually be anything. +# +# {'return': {}} is a QMPMessage, +# {} is the QMPReturnValue. + + +class QMPBadPortError(QMPError): + """ + Unable to parse socket address: Port was non-numerical. + """ + + +class QEMUMonitorProtocol: + """ + Provide an API to connect to QEMU via QEMU Monitor Protocol (QMP) + and then allow to handle commands and events. + + :param address: QEMU address, can be either a unix socket path (string) + or a tuple in the form ( address, port ) for a TCP + connection + :param server: Act as the socket server. (See 'accept') + :param nickname: Optional nickname used for logging. + """ + + def __init__(self, address: SocketAddrT, + server: bool = False, + nickname: Optional[str] = None): + + self._qmp = QMPClient(nickname) + self._aloop = asyncio.get_event_loop() + self._address = address + self._timeout: Optional[float] = None + + if server: + self._sync(self._qmp.start_server(self._address)) + + _T = TypeVar('_T') + + def _sync( + self, future: Awaitable[_T], timeout: Optional[float] = None + ) -> _T: + return self._aloop.run_until_complete( + asyncio.wait_for(future, timeout=timeout) + ) + + def _get_greeting(self) -> Optional[QMPMessage]: + if self._qmp.greeting is not None: + # pylint: disable=protected-access + return self._qmp.greeting._asdict() + return None + + def __enter__(self: _T) -> _T: + # Implement context manager enter function. + return self + + def __exit__(self, + # pylint: disable=duplicate-code + # see https://github.com/PyCQA/pylint/issues/3619 + exc_type: Optional[Type[BaseException]], + exc_val: Optional[BaseException], + exc_tb: Optional[TracebackType]) -> None: + # Implement context manager exit function. + self.close() + + @classmethod + def parse_address(cls, address: str) -> SocketAddrT: + """ + Parse a string into a QMP address. + + Figure out if the argument is in the port:host form. + If it's not, it's probably a file path. + """ + components = address.split(':') + if len(components) == 2: + try: + port = int(components[1]) + except ValueError: + msg = f"Bad port: '{components[1]}' in '{address}'." + raise QMPBadPortError(msg) from None + return (components[0], port) + + # Treat as filepath. + return address + + def connect(self, negotiate: bool = True) -> Optional[QMPMessage]: + """ + Connect to the QMP Monitor and perform capabilities negotiation. + + :return: QMP greeting dict, or None if negotiate is false + :raise ConnectError: on connection errors + """ + self._qmp.await_greeting = negotiate + self._qmp.negotiate = negotiate + + self._sync( + self._qmp.connect(self._address) + ) + return self._get_greeting() + + def accept(self, timeout: Optional[float] = 15.0) -> QMPMessage: + """ + Await connection from QMP Monitor and perform capabilities negotiation. + + :param timeout: + timeout in seconds (nonnegative float number, or None). + If None, there is no timeout, and this may block forever. + + :return: QMP greeting dict + :raise ConnectError: on connection errors + """ + self._qmp.await_greeting = True + self._qmp.negotiate = True + + self._sync(self._qmp.accept(), timeout) + + ret = self._get_greeting() + assert ret is not None + return ret + + def cmd_obj(self, qmp_cmd: QMPMessage) -> QMPMessage: + """ + Send a QMP command to the QMP Monitor. + + :param qmp_cmd: QMP command to be sent as a Python dict + :return: QMP response as a Python dict + """ + return dict( + self._sync( + # pylint: disable=protected-access + + # _raw() isn't a public API, because turning off + # automatic ID assignment is discouraged. For + # compatibility with iotests *only*, do it anyway. + self._qmp._raw(qmp_cmd, assign_id=False), + self._timeout + ) + ) + + def cmd(self, name: str, + args: Optional[Dict[str, object]] = None, + cmd_id: Optional[object] = None) -> QMPMessage: + """ + Build a QMP command and send it to the QMP Monitor. + + :param name: command name (string) + :param args: command arguments (dict) + :param cmd_id: command id (dict, list, string or int) + """ + qmp_cmd: QMPMessage = {'execute': name} + if args: + qmp_cmd['arguments'] = args + if cmd_id: + qmp_cmd['id'] = cmd_id + return self.cmd_obj(qmp_cmd) + + def command(self, cmd: str, **kwds: object) -> QMPReturnValue: + """ + Build and send a QMP command to the monitor, report errors if any + """ + return self._sync( + self._qmp.execute(cmd, kwds), + self._timeout + ) + + def pull_event(self, + wait: Union[bool, float] = False) -> Optional[QMPMessage]: + """ + Pulls a single event. + + :param wait: + If False or 0, do not wait. Return None if no events ready. + If True, wait forever until the next event. + Otherwise, wait for the specified number of seconds. + + :raise asyncio.TimeoutError: + When a timeout is requested and the timeout period elapses. + + :return: The first available QMP event, or None. + """ + if not wait: + # wait is False/0: "do not wait, do not except." + if self._qmp.events.empty(): + return None + + # If wait is 'True', wait forever. If wait is False/0, the events + # queue must not be empty; but it still needs some real amount + # of time to complete. + timeout = None + if wait and isinstance(wait, float): + timeout = wait + + return dict( + self._sync( + self._qmp.events.get(), + timeout + ) + ) + + def get_events(self, wait: Union[bool, float] = False) -> List[QMPMessage]: + """ + Get a list of QMP events and clear all pending events. + + :param wait: + If False or 0, do not wait. Return None if no events ready. + If True, wait until we have at least one event. + Otherwise, wait for up to the specified number of seconds for at + least one event. + + :raise asyncio.TimeoutError: + When a timeout is requested and the timeout period elapses. + + :return: A list of QMP events. + """ + events = [dict(x) for x in self._qmp.events.clear()] + if events: + return events + + event = self.pull_event(wait) + return [event] if event is not None else [] + + def clear_events(self) -> None: + """Clear current list of pending events.""" + self._qmp.events.clear() + + def close(self) -> None: + """Close the connection.""" + self._sync( + self._qmp.disconnect() + ) + + def settimeout(self, timeout: Optional[float]) -> None: + """ + Set the timeout for QMP RPC execution. + + This timeout affects the `cmd`, `cmd_obj`, and `command` methods. + The `accept`, `pull_event` and `get_event` methods have their + own configurable timeouts. + + :param timeout: + timeout in seconds, or None. + None will wait indefinitely. + """ + self._timeout = timeout + + def send_fd_scm(self, fd: int) -> None: + """ + Send a file descriptor to the remote via SCM_RIGHTS. + """ + self._qmp.send_fd_scm(fd) + + def __del__(self) -> None: + if self._qmp.runstate == Runstate.IDLE: + return + + if not self._aloop.is_running(): + self.close() + else: + # Garbage collection ran while the event loop was running. + # Nothing we can do about it now, but if we don't raise our + # own error, the user will be treated to a lot of traceback + # they might not understand. + raise QMPError( + "QEMUMonitorProtocol.close()" + " was not called before object was garbage collected" + ) |