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67 lines
2.1 KiB
67 lines
2.1 KiB
# -*- coding: utf-8 -*-
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# The LLVM Compiler Infrastructure
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#
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# This file is distributed under the University of Illinois Open Source
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# License. See LICENSE.TXT for details.
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""" This module implements basic shell escaping/unescaping methods. """
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import re
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import shlex
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__all__ = ['encode', 'decode']
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def encode(command):
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""" Takes a command as list and returns a string. """
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def needs_quote(word):
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""" Returns true if arguments needs to be protected by quotes.
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Previous implementation was shlex.split method, but that's not good
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for this job. Currently is running through the string with a basic
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state checking. """
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reserved = {' ', '$', '%', '&', '(', ')', '[', ']', '{', '}', '*', '|',
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'<', '>', '@', '?', '!'}
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state = 0
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for current in word:
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if state == 0 and current in reserved:
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return True
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elif state == 0 and current == '\\':
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state = 1
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elif state == 1 and current in reserved | {'\\'}:
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state = 0
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elif state == 0 and current == '"':
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state = 2
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elif state == 2 and current == '"':
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state = 0
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elif state == 0 and current == "'":
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state = 3
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elif state == 3 and current == "'":
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state = 0
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return state != 0
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def escape(word):
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""" Do protect argument if that's needed. """
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table = {'\\': '\\\\', '"': '\\"'}
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escaped = ''.join([table.get(c, c) for c in word])
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return '"' + escaped + '"' if needs_quote(word) else escaped
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return " ".join([escape(arg) for arg in command])
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def decode(string):
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""" Takes a command string and returns as a list. """
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def unescape(arg):
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""" Gets rid of the escaping characters. """
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if len(arg) >= 2 and arg[0] == arg[-1] and arg[0] == '"':
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arg = arg[1:-1]
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return re.sub(r'\\(["\\])', r'\1', arg)
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return re.sub(r'\\([\\ $%&\(\)\[\]\{\}\*|<>@?!])', r'\1', arg)
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return [unescape(arg) for arg in shlex.split(string)]
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