# Copyright 2016, Tresys Technology, LLC
#
# SPDX-License-Identifier: LGPL-2.1-only
#
from typing import NamedTuple
from ..policyrep import Context, FSUse
from .context import ContextWrapper
from .descriptors import DiffResultDescriptor
from .difference import Difference, Wrapper
class ModifiedFSUse(NamedTuple):
"""Difference details for a modified fs_use_*."""
rule: FSUse
added_context: Context
removed_context: 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) -> None:
"""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(ModifiedFSUse(left_rule,
right_rule.context,
left_rule.context))
#
# Internal functions
#
def _reset_diff(self) -> None:
"""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[FSUse]):
"""Wrap fs_use_* rules to allow set operations."""
__slots__ = ("ruletype", "fs", "context")
def __init__(self, rule: FSUse) -> None:
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
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