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# Copyright 2016, Tresys Technology, LLC
# Copyright 2018, Chris PeBenito <pebenito@ieee.org>
#
# This file is part of SETools.
#
# SETools is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 2.1 of
# the License, or (at your option) any later version.
#
# SETools 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with SETools. If not, see
# <http://www.gnu.org/licenses/>.
#
from collections import namedtuple
from ..policyrep import BoundsRuletype
from .descriptors import DiffResultDescriptor
from .difference import Difference, Wrapper
from .types import type_wrapper_factory
modified_bounds_record = namedtuple("modified_bound", ["rule", "added_bound", "removed_bound"])
class BoundsDifference(Difference):
"""Determine the difference in *bounds between two policies."""
added_typebounds = DiffResultDescriptor("diff_typebounds")
removed_typebounds = DiffResultDescriptor("diff_typebounds")
modified_typebounds = DiffResultDescriptor("diff_typebounds")
# Lists of rules for each policy
_left_typebounds = None
_right_typebounds = None
def diff_typebounds(self):
"""Generate the difference in typebound rules between the policies."""
self.log.info("Generating typebounds differences from {0.left_policy} to {0.right_policy}".
format(self))
if self._left_typebounds is None or self._right_typebounds is None:
self._create_typebound_lists()
self.added_typebounds, self.removed_typebounds, matched_typebounds = self._set_diff(
(BoundsWrapper(c) for c in self._left_typebounds),
(BoundsWrapper(c) for c in self._right_typebounds),
key=lambda b: str(b.child))
self.modified_typebounds = []
for left_bound, right_bound in matched_typebounds:
if type_wrapper_factory(left_bound.parent) != type_wrapper_factory(right_bound.parent):
self.modified_typebounds.append(modified_bounds_record(
left_bound, right_bound.parent, left_bound.parent))
#
# Internal functions
#
def _create_typebound_lists(self):
"""Create rule lists for both policies."""
self._left_typebounds = []
for rule in self.left_policy.bounds():
if rule.ruletype == BoundsRuletype.typebounds:
self._left_typebounds.append(rule)
else:
self.log.error("Unknown rule type: {0} (This is an SETools bug)".
format(rule.ruletype))
self._right_typebounds = []
for rule in self.right_policy.bounds():
if rule.ruletype == BoundsRuletype.typebounds:
self._right_typebounds.append(rule)
else:
self.log.error("Unknown rule type: {0} (This is an SETools bug)".
format(rule.ruletype))
def _reset_diff(self):
"""Reset diff results on policy changes."""
self.log.debug("Resetting all *bounds differences")
self.added_typebounds = None
self.removed_typebounds = None
# Sets of rules for each policy
self._left_typebounds = None
self._right_typebounds = None
class BoundsWrapper(Wrapper):
"""Wrap *bounds for diff purposes."""
__slots__ = ("ruletype", "parent", "child")
def __init__(self, rule):
self.origin = rule
self.ruletype = rule.ruletype
self.parent = type_wrapper_factory(rule.parent)
self.child = type_wrapper_factory(rule.child)
self.key = hash(rule)
def __hash__(self):
return self.key
def __lt__(self, other):
return self.key < other.key
def __eq__(self, other):
return self.ruletype == other.ruletype and \
self.child == other.child