154 lines
4.9 KiB
Python
154 lines
4.9 KiB
Python
#!/usr/bin/env python3
|
|
|
|
"""Sort file context definitions
|
|
|
|
The original setfiles sorting algorithm did not take into
|
|
account regular expression specificity. With the current
|
|
strict and targeted policies this is not an issue because
|
|
the file contexts are partially hand sorted and concatenated
|
|
in the right order so that the matches are generally correct.
|
|
The way reference policy and loadable policy modules handle
|
|
file contexts makes them come out in an unpredictable order
|
|
and therefore setfiles (or this standalone tool) need to sort
|
|
the regular expressions in a deterministic and stable way.
|
|
"""
|
|
|
|
import sys
|
|
import argparse
|
|
from pathlib import Path
|
|
import re
|
|
|
|
|
|
class FileContext():
|
|
""" Container class for file context defintions
|
|
"""
|
|
|
|
def __init__(self, context_line):
|
|
""" Constructor
|
|
"""
|
|
|
|
matches = re.match(r'^(?P<path>\S+)\s+(?P<type>-.)?\s*(?P<context>.+)$', context_line)
|
|
if matches is None:
|
|
raise ValueError
|
|
|
|
self.path, self.file_type, self.context = matches.group('path', 'type', 'context')
|
|
|
|
self.compute_diffdata()
|
|
|
|
def compute_diffdata(self):
|
|
""" Compute the interal values needed for comparing two file context definitions
|
|
"""
|
|
|
|
self.meta = False
|
|
self.stem_len = 0
|
|
self.str_len = 0
|
|
|
|
skip_escaped = False
|
|
|
|
for char in self.path:
|
|
if skip_escaped:
|
|
skip_escaped = False
|
|
continue
|
|
|
|
if char in ('.', '^', '$', '?', '*', '+', '|', '[', '(', '{',):
|
|
self.meta = True
|
|
if char == '\\':
|
|
skip_escaped = True
|
|
|
|
if not self.meta:
|
|
self.stem_len += 1
|
|
|
|
self.str_len += 1
|
|
|
|
@staticmethod
|
|
def _compare(a, b):
|
|
""" Compare two file context definitions
|
|
|
|
Returns:
|
|
-1 if a is less specific than b
|
|
0 if a and be are equally specific
|
|
1 if a is more specific than b
|
|
The comparison is based on the following statements,
|
|
in order from most important to least important, given a and b:
|
|
If a is a regular expression and b is not,
|
|
-> a is less specific than b.
|
|
If a's stem length is shorter than b's stem length,
|
|
-> a is less specific than b.
|
|
If a's string length is shorter than b's string length,
|
|
-> a is less specific than b.
|
|
If a does not have a specified type and b does,
|
|
-> a is less specific than b.
|
|
"""
|
|
|
|
# Check to see if either a or b have meta characters and the other doesn't
|
|
if a.meta and not b.meta:
|
|
return -1
|
|
if b.meta and not a.meta:
|
|
return 1
|
|
|
|
# Check to see if either a or b have a shorter stem length than the other
|
|
if a.stem_len < b.stem_len:
|
|
return -1
|
|
if b.stem_len < a.stem_len:
|
|
return 1
|
|
|
|
# Check to see if either a or b have a shorter string length than the other
|
|
if a.str_len < b.str_len:
|
|
return -1
|
|
if b.str_len < a.str_len:
|
|
return 1
|
|
|
|
# Check to see if either a or b has a specified type and the other doesn't
|
|
if not a.file_type and b.file_type:
|
|
return -1
|
|
if not b.file_type and a.file_type:
|
|
return 1
|
|
|
|
# If none of the above conditions were satisfied, then a and b are equally specific
|
|
return 0
|
|
|
|
def __lt__(self, other):
|
|
return self._compare(self, other) == -1
|
|
|
|
def __str__(self):
|
|
if self.file_type:
|
|
return '{}\t\t{}\t{}'.format(self.path, self.file_type, self.context)
|
|
else:
|
|
return '{}\t\t{}'.format(self.path, self.context)
|
|
|
|
|
|
if __name__ == '__main__':
|
|
|
|
parser = argparse.ArgumentParser(description='Sort file context definitions')
|
|
parser.add_argument('infile', metavar='INFILE', type=Path,
|
|
help='input file of the original file context definitions')
|
|
parser.add_argument('outfile', metavar='OUTFILE', nargs='?', type=Path, default=None,
|
|
help='output file for the sorted file context definitions')
|
|
args = parser.parse_args()
|
|
|
|
file_context_definitions = []
|
|
|
|
# Parse the input file
|
|
with args.infile.open('r') as fd:
|
|
for lineno, line in enumerate(fd, start=1):
|
|
line = line.strip()
|
|
|
|
# Ignore comments and empty lines
|
|
if not line or line.startswith('#'):
|
|
continue
|
|
|
|
try:
|
|
file_context_definitions.append(FileContext(line))
|
|
except ValueError:
|
|
print('{}:{}: unable to parse a file context line: {}'.format(args.infile, lineno, line))
|
|
exit(1)
|
|
|
|
# Sort
|
|
file_context_definitions.sort()
|
|
|
|
# Print output, either to file or if no output file given to stdout
|
|
|
|
with args.outfile.open('w') if args.outfile else sys.stdout as fd:
|
|
for fcd in file_context_definitions:
|
|
print(fcd, file=fd)
|