core-admin/qubes/__init__.py
Wojtek Porczyk 63c09a090c qubes: Combat import cycles
This commit eliminates import statements happening in the middle of the
file (between two classes definition). The cycles are still there. The
only magic module is qubes itself.
2016-05-05 14:33:09 +02:00

645 lines
20 KiB
Python

#!/usr/bin/python2 -O
# vim: fileencoding=utf-8
#
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2010-2015 Joanna Rutkowska <joanna@invisiblethingslab.com>
# Copyright (C) 2011-2015 Marek Marczykowski-Górecki
# <marmarek@invisiblethingslab.com>
# Copyright (C) 2014-2015 Wojtek Porczyk <woju@invisiblethingslab.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
'''
Qubes OS
:copyright: © 2010-2015 Invisible Things Lab
'''
from __future__ import absolute_import
__author__ = 'Invisible Things Lab'
__license__ = 'GPLv2 or later'
__version__ = 'R3'
import collections
import errno
import grp
import logging
import os
import os.path
import sys
import tempfile
import time
import __builtin__
import jinja2
import lxml.etree
import pkg_resources
import qubes.config
import qubes.events
import qubes.exc
class Label(object):
'''Label definition for virtual machines
Label specifies colour of the padlock displayed next to VM's name.
When this is a :py:class:`qubes.vm.dispvm.DispVM`, padlock is overlayed
with recycling pictogram.
:param int index: numeric identificator of label
:param str color: colour specification as in HTML (``#abcdef``)
:param str name: label's name like "red" or "green"
'''
def __init__(self, index, color, name):
#: numeric identificator of label
self.index = index
#: colour specification as in HTML (``#abcdef``)
self.color = color
#: label's name like "red" or "green"
self.name = name
#: freedesktop icon name, suitable for use in
#: :py:meth:`PyQt4.QtGui.QIcon.fromTheme`
self.icon = 'appvm-' + name
#: freedesktop icon name, suitable for use in
#: :py:meth:`PyQt4.QtGui.QIcon.fromTheme` on DispVMs
self.icon_dispvm = 'dispvm-' + name
@classmethod
def fromxml(cls, xml):
'''Create label definition from XML node
:param lxml.etree._Element xml: XML node reference
:rtype: :py:class:`qubes.Label`
'''
index = int(xml.get('id').split('-', 1)[1])
color = xml.get('color')
name = xml.text
return cls(index, color, name)
def __xml__(self):
element = lxml.etree.Element(
'label', id='label-{}'.format(self.index), color=self.color)
element.text = self.name
return element
def __str__(self):
return self.name
def __repr__(self):
return '{}({!r}, {!r}, {!r})'.format(
self.__class__.__name__,
self.index,
self.color,
self.name)
@__builtin__.property
def icon_path(self):
'''Icon path
.. deprecated:: 2.0
use :py:meth:`PyQt4.QtGui.QIcon.fromTheme` and :py:attr:`icon`
'''
return os.path.join(qubes.config.system_path['qubes_icon_dir'],
self.icon) + ".png"
@__builtin__.property
def icon_path_dispvm(self):
'''Icon path
.. deprecated:: 2.0
use :py:meth:`PyQt4.QtGui.QIcon.fromTheme` and :py:attr:`icon_dispvm`
'''
return os.path.join(qubes.config.system_path['qubes_icon_dir'],
self.icon_dispvm) + ".png"
class property(object): # pylint: disable=redefined-builtin,invalid-name
'''Qubes property.
This class holds one property that can be saved to and loaded from
:file:`qubes.xml`. It is used for both global and per-VM properties.
Property can be unset by ordinary ``del`` statement or assigning
:py:attr:`DEFAULT` special value to it. After deletion (or before first
assignment/load) attempting to read a property will get its default value
or, when no default, py:class:`exceptions.AttributeError`.
:param str name: name of the property
:param collections.Callable setter: if not :py:obj:`None`, this is used to \
initialise value; first parameter to the function is holder instance \
and the second is value; this is called before ``type``
:param collections.Callable saver: function to coerce value to something \
readable by setter
:param type type: if not :py:obj:`None`, value is coerced to this type
:param object default: default value; if callable, will be called with \
holder as first argument
:param int load_stage: stage when property should be loaded (see \
:py:class:`Qubes` for description of stages)
:param int order: order of evaluation (bigger order values are later)
:param bool clone: :py:meth:`PropertyHolder.clone_properties` will not \
include this property by default if :py:obj:`False`
:param str ls_head: column head for :program:`qvm-ls`
:param int ls_width: column width in :program:`qvm-ls`
:param str doc: docstring; this should be one paragraph of plain RST, no \
sphinx-specific features
Setters and savers have following signatures:
.. :py:function:: setter(self, prop, value)
:noindex:
:param self: instance of object that is holding property
:param prop: property object
:param value: value being assigned
.. :py:function:: saver(self, prop, value)
:noindex:
:param self: instance of object that is holding property
:param prop: property object
:param value: value being saved
:rtype: str
:raises property.DontSave: when property should not be saved at all
'''
#: Assigning this value to property means setting it to its default value.
#: If property has no default value, this will unset it.
DEFAULT = object()
# internal use only
_NO_DEFAULT = object()
def __init__(self, name, setter=None, saver=None, type=None,
default=_NO_DEFAULT, write_once=False, load_stage=2, order=0,
save_via_ref=False, clone=True,
ls_head=None, ls_width=None, doc=None):
# pylint: disable=redefined-builtin
self.__name__ = name
self._setter = setter
self._saver = saver if saver is not None else (
lambda self, prop, value: str(value))
self._type = type
self._default = default
self._write_once = write_once
self.order = order
self.load_stage = load_stage
self.save_via_ref = save_via_ref
self.clone = clone
self.__doc__ = doc
self._attr_name = '_qubesprop_' + name
if ls_head is not None or ls_width is not None:
self.ls_head = ls_head or self.__name__.replace('_', '-').upper()
self.ls_width = max(ls_width or 0, len(self.ls_head) + 1)
def __get__(self, instance, owner):
if instance is None:
return self
# XXX this violates duck typing, shall we keep it?
if not isinstance(instance, PropertyHolder):
raise AttributeError('qubes.property should be used on '
'qubes.PropertyHolder instances only')
try:
return getattr(instance, self._attr_name)
except AttributeError:
if self._default is self._NO_DEFAULT:
raise AttributeError(
'property {!r} not set'.format(self.__name__))
elif isinstance(self._default, collections.Callable):
return self._default(instance)
else:
return self._default
def __set__(self, instance, value):
self._enforce_write_once(instance)
if value is self.__class__.DEFAULT:
self.__delete__(instance)
return
try:
oldvalue = getattr(instance, self.__name__)
has_oldvalue = True
except AttributeError:
has_oldvalue = False
if self._setter is not None:
value = self._setter(instance, self, value)
if self._type not in (None, type(value)):
value = self._type(value)
if has_oldvalue:
instance.fire_event_pre('property-pre-set:' + self.__name__,
self.__name__, value, oldvalue)
else:
instance.fire_event_pre('property-pre-set:' + self.__name__,
self.__name__, value)
instance._property_init(self, value) # pylint: disable=protected-access
if has_oldvalue:
instance.fire_event('property-set:' + self.__name__, self.__name__,
value, oldvalue)
else:
instance.fire_event('property-set:' + self.__name__, self.__name__,
value)
def __delete__(self, instance):
self._enforce_write_once(instance)
try:
oldvalue = getattr(instance, self.__name__)
has_oldvalue = True
except AttributeError:
has_oldvalue = False
if has_oldvalue:
instance.fire_event_pre('property-pre-del:' + self.__name__,
self.__name__, oldvalue)
delattr(instance, self._attr_name)
instance.fire_event('property-del:' + self.__name__,
self.__name__, oldvalue)
else:
instance.fire_event_pre('property-pre-del:' + self.__name__,
self.__name__)
instance.fire_event('property-del:' + self.__name__,
self.__name__)
def __repr__(self):
default = ' default={!r}'.format(self._default) \
if self._default is not self._NO_DEFAULT \
else ''
return '<{} object at {:#x} name={!r}{}>'.format(
self.__class__.__name__, id(self), self.__name__, default) \
def __hash__(self):
return hash(self.__name__)
def __eq__(self, other):
return isinstance(other, property) and self.__name__ == other.__name__
def _enforce_write_once(self, instance):
if self._write_once and not instance.property_is_default(self):
raise AttributeError(
'property {!r} is write-once and already set'.format(
self.__name__))
#
# exceptions
#
class DontSave(Exception):
'''This exception may be raised from saver to sign that property should
not be saved.
'''
pass
@staticmethod
def dontsave(self, prop, value):
'''Dummy saver that never saves anything.'''
# pylint: disable=bad-staticmethod-argument,unused-argument
raise property.DontSave()
#
# some setters provided
#
@staticmethod
def forbidden(self, prop, value):
'''Property setter that forbids loading a property.
This is used to effectively disable property in classes which inherit
unwanted property. When someone attempts to load such a property, it
:throws AttributeError: always
''' # pylint: disable=bad-staticmethod-argument,unused-argument
raise AttributeError(
'setting {} property on {} instance is forbidden'.format(
prop.__name__, self.__class__.__name__))
@staticmethod
def bool(self, prop, value):
'''Property setter for boolean properties.
It accepts (case-insensitive) ``'0'``, ``'no'`` and ``false`` as
:py:obj:`False` and ``'1'``, ``'yes'`` and ``'true'`` as
:py:obj:`True`.
''' # pylint: disable=bad-staticmethod-argument,unused-argument
if isinstance(value, basestring):
lcvalue = value.lower()
if lcvalue in ('0', 'no', 'false', 'off'):
return False
if lcvalue in ('1', 'yes', 'true', 'on'):
return True
raise ValueError(
'Invalid literal for boolean property: {!r}'.format(value))
return bool(value)
class PropertyHolder(qubes.events.Emitter):
'''Abstract class for holding :py:class:`qubes.property`
Events fired by instances of this class:
.. event:: property-load (subject, event)
Fired once after all properties are loaded from XML. Individual
``property-set`` events are not fired.
.. event:: property-set:<propname> \
(subject, event, name, newvalue[, oldvalue])
Fired when property changes state. Signature is variable,
*oldvalue* is present only if there was an old value.
:param name: Property name
:param newvalue: New value of the property
:param oldvalue: Old value of the property
.. event:: property-pre-set:<propname> \
(subject, event, name, newvalue[, oldvalue])
Fired before property changes state. Signature is variable,
*oldvalue* is present only if there was an old value.
:param name: Property name
:param newvalue: New value of the property
:param oldvalue: Old value of the property
.. event:: property-del:<propname> \
(subject, event, name[, oldvalue])
Fired when property gets deleted (is set to default). Signature is
variable, *oldvalue* is present only if there was an old value.
:param name: Property name
:param oldvalue: Old value of the property
.. event:: property-pre-del:<propname> \
(subject, event, name[, oldvalue])
Fired before property gets deleted (is set to default). Signature
is variable, *oldvalue* is present only if there was an old value.
:param name: Property name
:param oldvalue: Old value of the property
Members:
'''
def __init__(self, xml, **kwargs):
self.xml = xml
propvalues = {}
all_names = set(prop.__name__ for prop in self.property_list())
for key in list(kwargs.keys()):
if not key in all_names:
continue
propvalues[key] = kwargs.pop(key)
super(PropertyHolder, self).__init__(**kwargs)
for key, value in propvalues.items():
setattr(self, key, value)
@classmethod
def property_list(cls, load_stage=None):
'''List all properties attached to this VM's class
:param load_stage: Filter by load stage
:type load_stage: :py:func:`int` or :py:obj:`None`
'''
props = set()
for class_ in cls.__mro__:
props.update(prop for prop in class_.__dict__.values()
if isinstance(prop, property))
if load_stage is not None:
props = set(prop for prop in props
if prop.load_stage == load_stage)
return sorted(props,
key=lambda prop: (prop.load_stage, prop.order, prop.__name__))
def _property_init(self, prop, value):
'''Initialise property to a given value, without side effects.
:param qubes.property prop: property object of particular interest
:param value: value
'''
# pylint: disable=protected-access
setattr(self, self.property_get_def(prop)._attr_name, value)
def property_is_default(self, prop):
'''Check whether property is in it's default value.
Properties when unset may return some default value, so
``hasattr(vm, prop.__name__)`` is wrong in some circumstances. This
method allows for checking if the value returned is in fact it's
default value.
:param qubes.property prop: property object of particular interest
:rtype: bool
''' # pylint: disable=protected-access
# both property_get_def() and ._attr_name may throw AttributeError,
# which we don't want to catch
attrname = self.property_get_def(prop)._attr_name
return not hasattr(self, attrname)
@classmethod
def property_get_def(cls, prop):
'''Return property definition object.
If prop is already :py:class:`qubes.property` instance, return the same
object.
:param prop: property object or name
:type prop: qubes.property or str
:rtype: qubes.property
'''
if isinstance(prop, qubes.property):
return prop
for p in cls.property_list():
if p.__name__ == prop:
return p
raise AttributeError('No property {!r} found in {!r}'.format(
prop, cls))
def load_properties(self, load_stage=None):
'''Load properties from immediate children of XML node.
``property-set`` events are not fired for each individual property.
:param int load_stage: Stage of loading.
'''
if self.xml is None:
return
all_names = set(
prop.__name__ for prop in self.property_list(load_stage))
for node in self.xml.xpath('./properties/property'):
name = node.get('name')
value = node.get('ref') or node.text
if not name in all_names:
continue
setattr(self, name, value)
def xml_properties(self, with_defaults=False):
'''Iterator that yields XML nodes representing set properties.
:param bool with_defaults: If :py:obj:`True`, then it also includes \
properties which were not set explicite, but have default values \
filled.
'''
properties = lxml.etree.Element('properties')
for prop in self.property_list():
# pylint: disable=protected-access
try:
value = getattr(
self, (prop.__name__ if with_defaults else prop._attr_name))
except AttributeError:
continue
try:
value = prop._saver(self, prop, value)
except property.DontSave:
continue
element = lxml.etree.Element('property', name=prop.__name__)
if prop.save_via_ref:
element.set('ref', value)
else:
element.text = value
properties.append(element)
return properties
# this was clone_attrs
def clone_properties(self, src, proplist=None):
'''Clone properties from other object.
:param PropertyHolder src: source object
:param list proplist: list of properties \
(:py:obj:`None` or omit for all properties except those with \
:py:attr:`property.clone` set to :py:obj:`False`)
'''
if proplist is None:
proplist = [prop for prop in self.property_list()
if prop.clone]
else:
proplist = [prop for prop in self.property_list()
if prop.__name__ in proplist or prop in proplist]
for prop in proplist:
try:
# pylint: disable=protected-access
self._property_init(prop, getattr(src, prop._attr_name))
except AttributeError:
continue
self.fire_event('clone-properties', src, proplist)
def property_require(self, prop, allow_none=False, hard=False):
'''Complain badly when property is not set.
:param prop: property name or object
:type prop: qubes.property or str
:param bool allow_none: if :py:obj:`True`, don't complain if \
:py:obj:`None` is found
:param bool hard: if :py:obj:`True`, raise :py:class:`AssertionError`; \
if :py:obj:`False`, log warning instead
'''
if isinstance(prop, qubes.property):
prop = prop.__name__
try:
value = getattr(self, prop)
if value is None and not allow_none:
raise AttributeError()
except AttributeError:
# pylint: disable=no-member
msg = 'Required property {!r} not set on {!r}'.format(prop, self)
if hard:
raise AssertionError(msg)
else:
# pylint: disable=no-member
self.log.fatal(msg)
from qubes.vm import VMProperty
from qubes.app import Qubes
__all__ = [
'Label',
'PropertyHolder',
'Qubes',
'VMProperty',
'property',
]