# Source code for sbws.util.stem

    import copy
    import logging
    import os
    from threading import RLock

    import socks
    import stem.process
    from stem import (
        ControllerError,
        InvalidArguments,
        InvalidRequest,
        OperationFailed,
        ProtocolError,
        SocketClosed,
        SocketError,
        UnsatisfiableRequest,
    )
    from stem.connection import IncorrectSocketType
    from stem.control import Controller, Listener

    from sbws import settings
    from sbws.globals import (
        TORRC_OPTIONS_CAN_FAIL,
        TORRC_RUNTIME_OPTIONS,
        TORRC_STARTING_POINT,
        fail_hard,
    )

    log = logging.getLogger(__name__)
    stream_building_lock = RLock()

    def attach_stream_to_circuit_listener(controller, circ_id):
        """Returns a function that should be given to add_event_listener(). It
        looks for newly created streams and attaches them to the given circ_id"""

        def closure_stream_event_listener(st):
            if st.status == "NEW" and st.purpose == "USER":
                log.debug(
                    "Attaching stream %s to circ %s %s",
                    st.id,
                    circ_id,
                    circuit_str(controller, circ_id),
                )
                try:
                    controller.attach_stream(st.id, circ_id)
                # So far we never saw this error.
                except (
                    UnsatisfiableRequest,
                    InvalidRequest,
                    OperationFailed,
                ) as e:
                    log.debug(
                        "Error attaching stream %s to circ %s: %s",
                        st.id,
                        circ_id,
                        e,
                    )
            else:
                pass

        return closure_stream_event_listener

    def add_event_listener(controller, func, event):
        try:
            controller.add_event_listener(func, event)
        except ProtocolError as e:
            log.exception("Exception trying to add event listener %s", e)

    def remove_event_listener(controller, func):
        try:
            controller.remove_event_listener(func)
        except SocketClosed as e:
            if not settings.end_event.is_set():
                log.debug(e)
            else:
                log.exception(e)
        except ProtocolError as e:
            log.exception("Exception trying to remove event %s", e)

    def init_controller(conf):
        c = None
        # If the external control port is set, use it to initialize the controller.
        control_port = conf["tor"]["external_control_port"]
        if control_port:
            control_port = int(control_port)
            # If it can not connect, the program will exit here
            c = _init_controller_port(control_port)
        # There is no configuration for external control socket, therefore do not
        # attempt to connect to the control socket.
        return c

    def is_bootstrapped(c):
        try:
            line = c.get_info("status/bootstrap-phase")
        except (ControllerError, InvalidArguments, ProtocolError) as e:
            log.exception("Error trying to check bootstrap phase %s", e)
            return False
        state, _, progress, *_ = line.split()
        progress = int(progress.split("=")[1])
        if state == "NOTICE" and progress == 100:
            return True
        log.debug("Not bootstrapped. state={} progress={}".format(state, progress))
        return False

    def _init_controller_port(port):
        assert isinstance(port, int)
        try:
            c = Controller.from_port(port=port)
            c.authenticate()
        except (IncorrectSocketType, SocketError):
            fail_hard("Unable to connect to control port %s.", port)
        # TODO: Allow for auth via more than just CookieAuthentication
        log.info("Connected to tor via port %s", port)
        return c

    def _init_controller_socket(socket):
        assert isinstance(socket, str)
        try:
            c = Controller.from_socket_file(path=socket)
            c.authenticate()
        except (IncorrectSocketType, SocketError):
            log.debug("Error initting controller socket: socket error.")
            return None
        except Exception as e:
            log.exception("Error initting controller socket: %s", e)
            return None
        # TODO: Allow for auth via more than just CookieAuthentication
        log.info("Connected to tor via socket %s", socket)
        return c

    def parse_user_torrc_config(torrc, torrc_text):
        """Parse the user configuration torrc text call `extra_lines`
        to a dictionary suitable to use with stem and return a new torrc
        dictionary that merges that dictionary with the existing torrc.
        Example::

            [tor]
            extra_lines =
                Log debug file /tmp/tor-debug.log
                NumCPUs 1
        """
        torrc_dict = torrc.copy()
        for line in torrc_text.split("\n"):
            # Remove leading and trailing whitespace, if any
            line = line.strip()
            # Ignore blank lines
            if len(line) < 1:
                continue
            # Some torrc options are only a key, some are a key value pair.
            kv = line.split(None, 1)
            if len(kv) > 1:
                key, value = kv
            else:
                key = kv[0]
                value = None
            # It's really easy to add to the torrc if the key doesn't exist
            if key not in torrc:
                torrc_dict.update({key: value})
            # But if it does, we have to make a list of values. For example, say
            # the user wants to add a SocksPort and we already have
            # 'SocksPort auto' in the torrc. We'll go from
            #     torrc['SocksPort'] == 'auto'
            # to
            #     torrc['SocksPort'] == ['auto', '9050']
            else:
                existing_val = torrc[key]
                if isinstance(existing_val, str):
                    torrc_dict.update({key: [existing_val, value]})
                else:
                    assert isinstance(existing_val, list)
                    existing_val.append(value)
                    torrc_dict.update({key: existing_val})
            log.debug(
                'Adding "%s %s" to torrc with which we are launching Tor',
                key,
                value,
            )
        return torrc_dict

    def set_torrc_starting_point(controller):
        """Set the torrc starting point options."""
        for k, v in TORRC_STARTING_POINT.items():
            try:
                controller.set_conf(k, v)
            except (ControllerError, InvalidRequest, InvalidArguments) as e:
                log.exception("Error setting option %s, %s: %s", k, v, e)
                exit(1)

    def set_torrc_runtime_options(controller):
        """Set torrc options at runtime."""
        try:
            controller.set_options(TORRC_RUNTIME_OPTIONS)
        # Only the first option that fails will be logged here.
        # Just log stem's exceptions.
        except (ControllerError, InvalidRequest, InvalidArguments) as e:
            log.exception(e)
            exit(1)

    def set_torrc_options_can_fail(controller):
        """Set options that can fail, at runtime.

        They can be set at launch, but since the may fail because they are not
        supported in some Tor versions, it's easier to try one by one at runtime
        and ignore the ones that fail.
        """
        for k, v in TORRC_OPTIONS_CAN_FAIL.items():
            try:
                controller.set_conf(k, v)
            except (InvalidArguments, InvalidRequest) as error:
                log.debug(
                    "Ignoring option not supported by this Tor version. %s", error
                )
            except ControllerError as e:
                log.exception(e)
                exit(1)

    def launch_tor(conf):
        os.makedirs(conf.getpath("tor", "datadir"), mode=0o700, exist_ok=True)
        os.makedirs(conf.getpath("tor", "log"), exist_ok=True)
        os.makedirs(conf.getpath("tor", "run_dpath"), mode=0o700, exist_ok=True)
        # Bare minimum things, more or less
        torrc = copy.deepcopy(TORRC_STARTING_POINT)
        # Very important and/or common settings that we don't know until runtime
        # The rest of the settings are in globals.py
        torrc.update(
            {
                "DataDirectory": conf.getpath("tor", "datadir"),
                "PidFile": conf.getpath("tor", "pid"),
                "ControlSocket": conf.getpath("tor", "control_socket"),
                "Log": [
                    "NOTICE file {}".format(
                        os.path.join(conf.getpath("tor", "log"), "notice.log")
                    ),
                ],
                "CircuitBuildTimeout": conf["general"]["circuit_timeout"],
            }
        )

        torrc = parse_user_torrc_config(torrc, conf["tor"]["extra_lines"])
        # Finally launch Tor
        try:
            # If there is already a tor process running with the same control
            # socket, this will exit here.
            stem.process.launch_tor_with_config(
                torrc, init_msg_handler=log.debug, take_ownership=True
            )
        except Exception as e:
            fail_hard("Error trying to launch tor: %s", e)
        log.info("Started own tor.")
        # And return a controller to it
        cont = _init_controller_socket(conf.getpath("tor", "control_socket"))
        # In the case it was not possible to connect to own tor socket.
        if not cont:
            fail_hard("Could not connect to own tor control socket.")
        return cont

    def launch_or_connect_to_tor(conf):
        cont = init_controller(conf)
        if not cont:
            cont = launch_tor(conf)
        else:
            if not is_torrc_starting_point_set(cont):
                set_torrc_starting_point(cont)
        # Set options that can fail at runtime
        set_torrc_options_can_fail(cont)
        # Set runtime options
        set_torrc_runtime_options(cont)
        log.info("Started or connected to Tor %s.", cont.get_version())
        return cont

    def get_socks_info(controller):
        """Returns the first SocksPort Tor is configured to listen on, in the form
        of an (address, port) tuple"""
        try:
            socks_ports = controller.get_listeners(Listener.SOCKS)
            return socks_ports[0]
        except SocketClosed as e:
            if not settings.end_event.is_set():
                log.debug(e)
        # This might need to return the exception if this happen in other cases
        # than when stopping the scanner.
        except ControllerError as e:
            log.debug(e)

    def only_relays_with_bandwidth(controller, relays, min_bw=None, max_bw=None):
        """
        Given a list of relays, only return those that optionally have above
        **min_bw** and optionally have below **max_bw**, inclusively. If neither
        min_bw nor max_bw are given, essentially just returns the input list of
        relays.
        """
        assert min_bw is None or min_bw >= 0
        assert max_bw is None or max_bw >= 0
        ret = []
        for relay in relays:
            assert hasattr(relay, "consensus_bandwidth")
            if min_bw is not None and relay.consensus_bandwidth < min_bw:
                continue
            if max_bw is not None and relay.consensus_bandwidth > max_bw:
                continue
            ret.append(relay)
        return ret

    def circuit_str(controller, circ_id):
        assert isinstance(circ_id, str)
        int(circ_id)
        try:
            circ = controller.get_circuit(circ_id)
        except ValueError as e:
            log.warning(
                "Circuit %s no longer seems to exist so can't return "
                "a valid circuit string for it: %s",
                circ_id,
                e,
            )
            return None
        # exceptions raised when stopping the scanner
        except (ControllerError, SocketClosed, socks.GeneralProxyError) as e:
            log.debug(e)
            return None
        return (
            "["
            + " -> ".join(["{} ({})".format(n, fp[0:8]) for fp, n in circ.path])
            + "]"
        )

    def is_torrc_starting_point_set(tor_controller):
        """Verify that the tor controller has the correct configuration.

        When connecting to a tor controller that has not been launched by sbws,
        it should have been configured to work with sbws.

        """
        bad_options = False
        torrc = TORRC_STARTING_POINT
        for k, v in torrc.items():
            value_set = tor_controller.get_conf(k)
            if v != value_set:
                log.exception(
                    "Incorrectly configured %s, should be %s, is %s",
                    k,
                    v,
                    value_set,
                )
                bad_options = True
        if not bad_options:
            log.info("Tor is correctly configured to work with sbws.")
        return bad_options