mirror of
git://sourceware.org/git/lvm2.git
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309 lines
9.1 KiB
Python
309 lines
9.1 KiB
Python
# Copyright (C) 2015-2016 Red Hat, Inc. All rights reserved.
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#
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# This copyrighted material is made available to anyone wishing to use,
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# modify, copy, or redistribute it subject to the terms and conditions
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# of the GNU General Public License v.2.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import sys
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import threading
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import traceback
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import dbus
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import os
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from . import cfg
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from .utils import log_debug
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from .automatedproperties import AutomatedProperties
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# noinspection PyPep8Naming
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class ObjectManager(AutomatedProperties):
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"""
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Implements the org.freedesktop.DBus.ObjectManager interface
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"""
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def __init__(self, object_path, interface):
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super(ObjectManager, self).__init__(object_path, interface)
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self.set_interface(interface)
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self._ap_o_path = object_path
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self._objects = {}
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self._id_to_object_path = {}
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self.rlock = threading.RLock()
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@dbus.service.method(
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dbus_interface="org.freedesktop.DBus.ObjectManager",
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out_signature='a{oa{sa{sv}}}')
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def GetManagedObjects(self):
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with self.rlock:
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rc = {}
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try:
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for k, v in list(self._objects.items()):
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path, props = v[0].emit_data()
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rc[path] = props
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except Exception:
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traceback.print_exc(file=sys.stdout)
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sys.exit(1)
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return rc
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def locked(self):
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"""
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If some external code need to run across a number of different
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calls into ObjectManager while blocking others they can use this method
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to lock others out.
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:return:
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"""
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return ObjectManagerLock(self.rlock)
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@dbus.service.signal(
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dbus_interface="org.freedesktop.DBus.ObjectManager",
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signature='oa{sa{sv}}')
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def InterfacesAdded(self, object_path, int_name_prop_dict):
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log_debug(
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('SIGNAL: InterfacesAdded(%s, %s)' %
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(str(object_path), str(int_name_prop_dict))))
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@dbus.service.signal(
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dbus_interface="org.freedesktop.DBus.ObjectManager",
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signature='oas')
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def InterfacesRemoved(self, object_path, interface_list):
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log_debug(('SIGNAL: InterfacesRemoved(%s, %s)' %
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(str(object_path), str(interface_list))))
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def _lookup_add(self, obj, path, lvm_id, uuid):
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"""
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Store information about what we added to the caches so that we
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can remove it cleanly
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:param obj: The dbus object we are storing
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:param lvm_id: The user name for the asset
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:param uuid: The uuid for the asset
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:return:
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"""
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# Note: Only called internally, lock implied
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# We could have a temp entry from the forward creation of a path
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self._lookup_remove(path)
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self._objects[path] = (obj, lvm_id, uuid)
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self._id_to_object_path[lvm_id] = path
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if uuid:
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self._id_to_object_path[uuid] = path
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def _lookup_remove(self, obj_path):
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# Note: Only called internally, lock implied
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if obj_path in self._objects:
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(obj, lvm_id, uuid) = self._objects[obj_path]
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del self._id_to_object_path[lvm_id]
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del self._id_to_object_path[uuid]
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del self._objects[obj_path]
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def lookup_update(self, dbus_obj, new_uuid, new_lvm_id):
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with self.rlock:
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obj_path = dbus_obj.dbus_object_path()
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self._lookup_remove(obj_path)
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self._lookup_add(
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dbus_obj, obj_path,
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new_lvm_id, new_uuid)
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def object_paths_by_type(self, o_type):
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with self.rlock:
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rc = {}
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for k, v in list(self._objects.items()):
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if isinstance(v[0], o_type):
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rc[k] = True
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return rc
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def register_object(self, dbus_object, emit_signal=False):
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"""
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Given a dbus object add it to the collection
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:param dbus_object: Dbus object to register
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:param emit_signal: If true emit a signal for interfaces added
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"""
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with self.rlock:
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path, props = dbus_object.emit_data()
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# print('Registering object path %s for %s' %
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# (path, dbus_object.lvm_id))
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# We want fast access to the object by a number of different ways
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# so we use multiple hashs with different keys
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self._lookup_add(dbus_object, path, dbus_object.lvm_id,
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dbus_object.Uuid)
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if emit_signal:
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self.InterfacesAdded(path, props)
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def remove_object(self, dbus_object, emit_signal=False):
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"""
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Given a dbus object, remove it from the collection and remove it
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from the dbus framework as well
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:param dbus_object: Dbus object to remove
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:param emit_signal: If true emit the interfaces removed signal
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"""
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with self.rlock:
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# Store off the object path and the interface first
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path = dbus_object.dbus_object_path()
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interfaces = dbus_object.interface()
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# print 'UN-Registering object path %s for %s' % \
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# (path, dbus_object.lvm_id)
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self._lookup_remove(path)
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# Remove from dbus library
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dbus_object.remove_from_connection(cfg.bus, path)
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# Optionally emit a signal
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if emit_signal:
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self.InterfacesRemoved(path, interfaces)
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def get_object_by_path(self, path):
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"""
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Given a dbus path return the object registered for it
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:param path: The dbus path
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:return: The object
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"""
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with self.rlock:
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if path in self._objects:
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return self._objects[path][0]
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return None
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def get_object_by_uuid_lvm_id(self, uuid, lvm_id):
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with self.rlock:
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return self.get_object_by_path(
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self.get_object_path_by_uuid_lvm_id(uuid, lvm_id, None, False))
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def get_object_by_lvm_id(self, lvm_id):
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"""
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Given an lvm identifier, return the object registered for it
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:param lvm_id: The lvm identifier
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"""
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with self.rlock:
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if lvm_id in self._id_to_object_path:
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return self.get_object_by_path(self._id_to_object_path[lvm_id])
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return None
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def get_object_path_by_lvm_id(self, lvm_id):
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"""
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Given an lvm identifier, return the object path for it
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:param lvm_id: The lvm identifier
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:return: Object path or '/' if not found
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"""
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with self.rlock:
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if lvm_id in self._id_to_object_path:
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return self._id_to_object_path[lvm_id]
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return '/'
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def _uuid_verify(self, path, uuid, lvm_id):
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"""
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Ensure uuid is present for a successful lvm_id lookup
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NOTE: Internal call, assumes under object manager lock
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:param path: Path to object we looked up
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:param uuid: lvm uuid to verify
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:param lvm_id: lvm_id used to find object
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:return: None
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"""
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# This gets called when we found an object based on lvm_id, ensure
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# uuid is correct too, as they can change
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if lvm_id != uuid:
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if uuid not in self._id_to_object_path:
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obj = self.get_object_by_path(path)
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self._lookup_add(obj, path, lvm_id, uuid)
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def _return_lookup(self, uuid, lvm_identifier):
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"""
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We found an identifier, so lets return the path to the found object
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:param uuid: The lvm uuid
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:param lvm_identifier: The lvm_id used to find object
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:return:
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"""
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path = self._id_to_object_path[lvm_identifier]
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self._uuid_verify(path, uuid, lvm_identifier)
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return path
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def get_object_path_by_uuid_lvm_id(self, uuid, lvm_id, path_create=None,
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gen_new=True):
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"""
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For a given lvm asset return the dbus object registered to it. If the
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object is not found and gen_new == True and path_create is a valid
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function we will create a new path, register it and return it.
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:param uuid: The uuid for the lvm object
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:param lvm_id: The lvm name
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:param path_create: If true create an object path if not found
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:param gen_new: The function used to create the new path
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"""
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with self.rlock:
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assert lvm_id
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assert uuid
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if gen_new:
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assert path_create
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path = None
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if lvm_id in self._id_to_object_path:
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self._return_lookup(uuid, lvm_id)
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if "/" in lvm_id:
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vg, lv = lvm_id.split("/", 1)
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int_lvm_id = vg + "/" + ("[%s]" % lv)
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if int_lvm_id in self._id_to_object_path:
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self._return_lookup(uuid, int_lvm_id)
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elif lvm_id.startswith('/'):
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# We could have a pv device path lookup that failed,
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# lets try canonical form and try again.
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canonical = os.path.realpath(lvm_id)
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if canonical in self._id_to_object_path:
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self._return_lookup(uuid, canonical)
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if uuid and uuid in self._id_to_object_path:
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# If we get here it indicates that we found the object, but
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# the lvm_id lookup failed. In the case of a rename, the uuid
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# will be correct, but the lvm_id will be wrong and vise versa.
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# If the lvm_id does not equal the uuid, lets fix up the table
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# so that lookups will be handled correctly.
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path = self._id_to_object_path[uuid]
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# In some cases we are looking up by one or the other, don't
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# update when they are the same.
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if uuid != lvm_id:
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obj = self.get_object_by_path(path)
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self._lookup_add(obj, path, lvm_id, uuid)
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else:
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if gen_new:
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path = path_create()
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self._lookup_add(None, path, lvm_id, uuid)
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# pprint('get_object_path_by_lvm_id(%s, %s, %s, %s: return %s' %
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# (uuid, lvm_id, str(path_create), str(gen_new), path))
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return path
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class ObjectManagerLock(object):
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"""
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The sole purpose of this class is to allow other code the ability to
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lock the object manager using a `with` statement, eg.
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with cfg.om.locked():
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# Do stuff with object manager
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This will ensure that the lock is always released (assuming this is done
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correctly)
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"""
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def __init__(self, recursive_lock):
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self._lock = recursive_lock
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def __enter__(self):
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# Acquire lock
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self._lock.acquire()
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# noinspection PyUnusedLocal
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def __exit__(self, e_type, e_value, e_traceback):
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# Release lock
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self._lock.release()
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self._lock = None
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