| Current File : //usr/lib/python3/dist-packages/dbus/bus.py |
# Copyright (C) 2007 Collabora Ltd. <http://www.collabora.co.uk/>
#
# SPDX-License-Identifier: MIT
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use, copy,
# modify, merge, publish, distribute, sublicense, and/or sell copies
# of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
__all__ = ('BusConnection',)
__docformat__ = 'reStructuredText'
import logging
import weakref
from _dbus_bindings import (
BUS_DAEMON_IFACE, BUS_DAEMON_NAME, BUS_DAEMON_PATH, BUS_SESSION,
BUS_STARTER, BUS_SYSTEM, DBUS_START_REPLY_ALREADY_RUNNING,
DBUS_START_REPLY_SUCCESS, NAME_FLAG_ALLOW_REPLACEMENT,
NAME_FLAG_DO_NOT_QUEUE, NAME_FLAG_REPLACE_EXISTING,
RELEASE_NAME_REPLY_NON_EXISTENT, RELEASE_NAME_REPLY_NOT_OWNER,
RELEASE_NAME_REPLY_RELEASED, REQUEST_NAME_REPLY_ALREADY_OWNER,
REQUEST_NAME_REPLY_EXISTS, REQUEST_NAME_REPLY_IN_QUEUE,
REQUEST_NAME_REPLY_PRIMARY_OWNER, validate_bus_name, validate_error_name,
validate_interface_name, validate_member_name, validate_object_path)
from dbus.connection import Connection
from dbus.exceptions import DBusException
from dbus.lowlevel import HANDLER_RESULT_NOT_YET_HANDLED
from dbus._compat import is_py2
_NAME_OWNER_CHANGE_MATCH = ("type='signal',sender='%s',"
"interface='%s',member='NameOwnerChanged',"
"path='%s',arg0='%%s'"
% (BUS_DAEMON_NAME, BUS_DAEMON_IFACE,
BUS_DAEMON_PATH))
"""(_NAME_OWNER_CHANGE_MATCH % sender) matches relevant NameOwnerChange
messages"""
_NAME_HAS_NO_OWNER = 'org.freedesktop.DBus.Error.NameHasNoOwner'
_logger = logging.getLogger('dbus.bus')
class NameOwnerWatch(object):
__slots__ = ('_match', '_pending_call')
def __init__(self, bus_conn, bus_name, callback):
validate_bus_name(bus_name)
def signal_cb(owned, old_owner, new_owner):
callback(new_owner)
def error_cb(e):
if e.get_dbus_name() == _NAME_HAS_NO_OWNER:
callback('')
else:
logging.basicConfig()
_logger.debug('GetNameOwner(%s) failed:', bus_name,
exc_info=(e.__class__, e, None))
self._match = bus_conn.add_signal_receiver(signal_cb,
'NameOwnerChanged',
BUS_DAEMON_IFACE,
BUS_DAEMON_NAME,
BUS_DAEMON_PATH,
arg0=bus_name)
self._pending_call = bus_conn.call_async(BUS_DAEMON_NAME,
BUS_DAEMON_PATH,
BUS_DAEMON_IFACE,
'GetNameOwner',
's', (bus_name,),
callback, error_cb)
def cancel(self):
if self._match is not None:
self._match.remove()
if self._pending_call is not None:
self._pending_call.cancel()
self._match = None
self._pending_call = None
class BusConnection(Connection):
"""A connection to a D-Bus daemon that implements the
``org.freedesktop.DBus`` pseudo-service.
:Since: 0.81.0
"""
TYPE_SESSION = BUS_SESSION
"""Represents a session bus (same as the global dbus.BUS_SESSION)"""
TYPE_SYSTEM = BUS_SYSTEM
"""Represents the system bus (same as the global dbus.BUS_SYSTEM)"""
TYPE_STARTER = BUS_STARTER
"""Represents the bus that started this service by activation (same as
the global dbus.BUS_STARTER)"""
START_REPLY_SUCCESS = DBUS_START_REPLY_SUCCESS
START_REPLY_ALREADY_RUNNING = DBUS_START_REPLY_ALREADY_RUNNING
def __new__(cls, address_or_type=TYPE_SESSION, mainloop=None):
bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
# _bus_names is used by dbus.service.BusName!
bus._bus_names = weakref.WeakValueDictionary()
bus._signal_sender_matches = {}
"""Map from SignalMatch to NameOwnerWatch."""
return bus
def add_signal_receiver(self, handler_function, signal_name=None,
dbus_interface=None, bus_name=None,
path=None, **keywords):
named_service = keywords.pop('named_service', None)
if named_service is not None:
if bus_name is not None:
raise TypeError('bus_name and named_service cannot both be '
'specified')
bus_name = named_service
from warnings import warn
warn('Passing the named_service parameter to add_signal_receiver '
'by name is deprecated: please use positional parameters',
DeprecationWarning, stacklevel=2)
match = super(BusConnection, self).add_signal_receiver(
handler_function, signal_name, dbus_interface, bus_name,
path, **keywords)
if (bus_name is not None and bus_name != BUS_DAEMON_NAME):
if bus_name[:1] == ':':
def callback(new_owner):
if new_owner == '':
match.remove()
else:
callback = match.set_sender_name_owner
watch = self.watch_name_owner(bus_name, callback)
self._signal_sender_matches[match] = watch
self.add_match_string(str(match))
return match
def _clean_up_signal_match(self, match):
# The signals lock is no longer held here (it was in <= 0.81.0)
self.remove_match_string_non_blocking(str(match))
watch = self._signal_sender_matches.pop(match, None)
if watch is not None:
watch.cancel()
def activate_name_owner(self, bus_name):
if (bus_name is not None and bus_name[:1] != ':'
and bus_name != BUS_DAEMON_NAME):
try:
return self.get_name_owner(bus_name)
except DBusException as e:
if e.get_dbus_name() != _NAME_HAS_NO_OWNER:
raise
# else it doesn't exist: try to start it
self.start_service_by_name(bus_name)
return self.get_name_owner(bus_name)
else:
# already unique
return bus_name
def get_object(self, bus_name, object_path, introspect=True,
follow_name_owner_changes=False, **kwargs):
"""Return a local proxy for the given remote object.
Method calls on the proxy are translated into method calls on the
remote object.
:Parameters:
`bus_name` : str
A bus name (either the unique name or a well-known name)
of the application owning the object. The keyword argument
named_service is a deprecated alias for this.
`object_path` : str
The object path of the desired object
`introspect` : bool
If true (default), attempt to introspect the remote
object to find out supported methods and their signatures
`follow_name_owner_changes` : bool
If the object path is a well-known name and this parameter
is false (default), resolve the well-known name to the unique
name of its current owner and bind to that instead; if the
ownership of the well-known name changes in future,
keep communicating with the original owner.
This is necessary if the D-Bus API used is stateful.
If the object path is a well-known name and this parameter
is true, whenever the well-known name changes ownership in
future, bind to the new owner, if any.
If the given object path is a unique name, this parameter
has no effect.
:Returns: a `dbus.proxies.ProxyObject`
:Raises `DBusException`: if resolving the well-known name to a
unique name fails
"""
if follow_name_owner_changes:
self._require_main_loop() # we don't get the signals otherwise
named_service = kwargs.pop('named_service', None)
if named_service is not None:
if bus_name is not None:
raise TypeError('bus_name and named_service cannot both '
'be specified')
from warnings import warn
warn('Passing the named_service parameter to get_object by name '
'is deprecated: please use positional parameters',
DeprecationWarning, stacklevel=2)
bus_name = named_service
if kwargs:
raise TypeError('get_object does not take these keyword '
'arguments: %s' % ', '.join(kwargs.keys()))
return self.ProxyObjectClass(self, bus_name, object_path,
introspect=introspect,
follow_name_owner_changes=follow_name_owner_changes)
def get_unix_user(self, bus_name):
"""Get the numeric uid of the process owning the given bus name.
:Parameters:
`bus_name` : str
A bus name, either unique or well-known
:Returns: a `dbus.UInt32`
:Since: 0.80.0
"""
validate_bus_name(bus_name)
return self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'GetConnectionUnixUser',
's', (bus_name,))
def start_service_by_name(self, bus_name, flags=0):
"""Start a service which will implement the given bus name on this Bus.
:Parameters:
`bus_name` : str
The well-known bus name to be activated.
`flags` : dbus.UInt32
Flags to pass to StartServiceByName (currently none are
defined)
:Returns: A tuple of 2 elements. The first is always True, the
second is either START_REPLY_SUCCESS or
START_REPLY_ALREADY_RUNNING.
:Raises `DBusException`: if the service could not be started.
:Since: 0.80.0
"""
validate_bus_name(bus_name)
return (True, self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE,
'StartServiceByName',
'su', (bus_name, flags)))
# XXX: it might be nice to signal IN_QUEUE, EXISTS by exception,
# but this would not be backwards-compatible
def request_name(self, name, flags=0):
"""Request a bus name.
:Parameters:
`name` : str
The well-known name to be requested
`flags` : dbus.UInt32
A bitwise-OR of 0 or more of the flags
`NAME_FLAG_ALLOW_REPLACEMENT`,
`NAME_FLAG_REPLACE_EXISTING`
and `NAME_FLAG_DO_NOT_QUEUE`
:Returns: `REQUEST_NAME_REPLY_PRIMARY_OWNER`,
`REQUEST_NAME_REPLY_IN_QUEUE`,
`REQUEST_NAME_REPLY_EXISTS` or
`REQUEST_NAME_REPLY_ALREADY_OWNER`
:Raises `DBusException`: if the bus daemon cannot be contacted or
returns an error.
"""
validate_bus_name(name, allow_unique=False)
return self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'RequestName',
'su', (name, flags))
def release_name(self, name):
"""Release a bus name.
:Parameters:
`name` : str
The well-known name to be released
:Returns: `RELEASE_NAME_REPLY_RELEASED`,
`RELEASE_NAME_REPLY_NON_EXISTENT`
or `RELEASE_NAME_REPLY_NOT_OWNER`
:Raises `DBusException`: if the bus daemon cannot be contacted or
returns an error.
"""
validate_bus_name(name, allow_unique=False)
return self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'ReleaseName',
's', (name,))
def list_names(self):
"""Return a list of all currently-owned names on the bus.
:Returns: a dbus.Array of dbus.UTF8String
:Since: 0.81.0
"""
return self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'ListNames',
'', ())
def list_activatable_names(self):
"""Return a list of all names that can be activated on the bus.
:Returns: a dbus.Array of dbus.UTF8String
:Since: 0.81.0
"""
return self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'ListActivatableNames',
'', ())
def get_name_owner(self, bus_name):
"""Return the unique connection name of the primary owner of the
given name.
:Raises `DBusException`: if the `bus_name` has no owner
:Since: 0.81.0
"""
validate_bus_name(bus_name, allow_unique=False)
return self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'GetNameOwner',
's', (bus_name,))
def watch_name_owner(self, bus_name, callback):
"""Watch the unique connection name of the primary owner of the
given name.
`callback` will be called with one argument, which is either the
unique connection name, or the empty string (meaning the name is
not owned).
:Since: 0.81.0
"""
return NameOwnerWatch(self, bus_name, callback)
def name_has_owner(self, bus_name):
"""Return True iff the given bus name has an owner on this bus.
:Parameters:
`bus_name` : str
The bus name to look up
:Returns: a `bool`
"""
return bool(self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'NameHasOwner',
's', (bus_name,)))
def add_match_string(self, rule):
"""Arrange for this application to receive messages on the bus that
match the given rule. This version will block.
:Parameters:
`rule` : str
The match rule
:Raises `DBusException`: on error.
:Since: 0.80.0
"""
self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'AddMatch', 's', (rule,))
# FIXME: add an async success/error handler capability?
# (and the same for remove_...)
def add_match_string_non_blocking(self, rule):
"""Arrange for this application to receive messages on the bus that
match the given rule. This version will not block, but any errors
will be ignored.
:Parameters:
`rule` : str
The match rule
:Raises `DBusException`: on error.
:Since: 0.80.0
"""
self.call_async(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'AddMatch', 's', (rule,),
None, None)
def remove_match_string(self, rule):
"""Arrange for this application to receive messages on the bus that
match the given rule. This version will block.
:Parameters:
`rule` : str
The match rule
:Raises `DBusException`: on error.
:Since: 0.80.0
"""
self.call_blocking(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'RemoveMatch', 's', (rule,))
def remove_match_string_non_blocking(self, rule):
"""Arrange for this application to receive messages on the bus that
match the given rule. This version will not block, but any errors
will be ignored.
:Parameters:
`rule` : str
The match rule
:Raises `DBusException`: on error.
:Since: 0.80.0
"""
self.call_async(BUS_DAEMON_NAME, BUS_DAEMON_PATH,
BUS_DAEMON_IFACE, 'RemoveMatch', 's', (rule,),
None, None)