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# Copyright 2016, Tresys Technology, LLC
#
# 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 .context import ContextWrapper
from .descriptors import DiffResultDescriptor
from .difference import Difference, Wrapper
modified_fsuse_record = namedtuple("modified_fsuse", ["rule",
"added_context",
"removed_context"])
class FSUsesDifference(Difference):
"""Determine the difference in fs_use_* rules between two policies."""
added_fs_uses = DiffResultDescriptor("diff_fs_uses")
removed_fs_uses = DiffResultDescriptor("diff_fs_uses")
modified_fs_uses = DiffResultDescriptor("diff_fs_uses")
def diff_fs_uses(self):
"""Generate the difference in fs_use rules between the policies."""
self.log.info(
"Generating fs_use_* differences from {0.left_policy} to {0.right_policy}".
format(self))
self.added_fs_uses, self.removed_fs_uses, matched = self._set_diff(
(FSUseWrapper(fs) for fs in self.left_policy.fs_uses()),
(FSUseWrapper(fs) for fs in self.right_policy.fs_uses()))
self.modified_fs_uses = []
for left_rule, right_rule in matched:
# Criteria for modified rules
# 1. change to context
if ContextWrapper(left_rule.context) != ContextWrapper(right_rule.context):
self.modified_fs_uses.append(modified_fsuse_record(left_rule,
right_rule.context,
left_rule.context))
#
# Internal functions
#
def _reset_diff(self):
"""Reset diff results on policy changes."""
self.log.debug("Resetting fs_use_* rule differences")
self.added_fs_uses = None
self.removed_fs_uses = None
self.modified_fs_uses = None
class FSUseWrapper(Wrapper):
"""Wrap fs_use_* rules to allow set operations."""
__slots__ = ("ruletype", "fs", "context")
def __init__(self, rule):
self.origin = rule
self.ruletype = rule.ruletype
self.fs = rule.fs
self.context = ContextWrapper(rule.context)
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.fs == other.fs