# Copyright 2018 The Chromium OS Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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import os
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import glob
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import re
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# Matching a string of length m in an NFA of size n is O(mn^2), but the
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# performance also depends largely on the implementation. It appears to be fast
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# enough according to the tests.
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#
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# The performance bottleneck of this script is readelf. Unless this becomes
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# slower than readelf, don't waste time here.
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def is_whitelisted(list_name, pattern):
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"""chech whether the given pattern is specified in the whitelist.
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Args:
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list_name: name of the whitelist
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pattern: the target string
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Returns:
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True if matched otherwise False
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"""
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return pattern and whitelists[list_name].match(pattern)
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def prepare_whitelist(patterns):
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"""Join and compile the re patterns.
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Args:
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patterns: regex patterns.
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Return:
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A compiled re object
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"""
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return re.compile('|'.join(patterns))
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def load_whitelists(dirname):
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"""Load whitelists under dirname.
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A whitelist ends with .whitelist.
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Args:
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dirname: path to the dir.
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Returns:
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A dictionary of 'filename' -> whitelist matcher.
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"""
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wlist = {}
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for fn in glob.glob(os.path.join(dirname, '*.whitelist')):
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key = os.path.splitext(os.path.basename(fn))[0]
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with open(fn, 'r') as f:
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patterns = f.read().splitlines()
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patterns = [l for l in patterns if l != '']
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patterns = [l for l in patterns if l[0] != '#']
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wlist[key] = prepare_whitelist(patterns)
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return wlist
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whitelists = load_whitelists(os.path.dirname(__file__))
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