# Copyright 2016, Tresys Technology, LLC
#
# SPDX-License-Identifier: LGPL-2.1-only
#
from typing import NamedTuple
from ..policyrep import Context, Genfscon
from .context import ContextWrapper
from .descriptors import DiffResultDescriptor
from .difference import Difference, Wrapper
class ModifiedGenfscon(NamedTuple):
"""Difference details for a modified genfscons."""
rule: Genfscon
added_context: Context
removed_context: Context
class GenfsconsDifference(Difference):
"""Determine the difference in genfscon rules between two policies."""
added_genfscons = DiffResultDescriptor("diff_genfscons")
removed_genfscons = DiffResultDescriptor("diff_genfscons")
modified_genfscons = DiffResultDescriptor("diff_genfscons")
def diff_genfscons(self) -> None:
"""Generate the difference in genfscon rules between the policies."""
self.log.info(
"Generating genfscon differences from {0.left_policy} to {0.right_policy}".
format(self))
self.added_genfscons, self.removed_genfscons, matched = self._set_diff(
(GenfsconWrapper(fs) for fs in self.left_policy.genfscons()),
(GenfsconWrapper(fs) for fs in self.right_policy.genfscons()))
self.modified_genfscons = []
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_genfscons.append(ModifiedGenfscon(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 genfscon rule differences")
self.added_genfscons = None
self.removed_genfscons = None
self.modified_genfscons = None
class GenfsconWrapper(Wrapper[Genfscon]):
"""Wrap genfscon rules to allow set operations."""
__slots__ = ("fs", "path", "filetype", "context")
def __init__(self, rule: Genfscon) -> None:
self.origin = rule
self.fs = rule.fs
self.path = rule.path
self.filetype = rule.filetype
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.fs == other.fs and \
self.path == other.path and \
self.filetype == other.filetype
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