83 lines
2.3 KiB
Python
83 lines
2.3 KiB
Python
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# -*- coding: utf-8 -*-
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# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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# See https://llvm.org/LICENSE.txt for license information.
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# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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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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"$",
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"%",
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"&",
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"(",
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")",
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"[",
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"]",
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"{",
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"}",
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"*",
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"|",
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"<",
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">",
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"@",
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"?",
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"!",
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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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