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