"Fossies" - the Fresh Open Source Software Archive

Member "polysh-polysh-0.13/polysh/callbacks.py" (11 May 2020, 2888 Bytes) of package /linux/privat/polysh-polysh-0.13.tar.gz:

    1 """Polysh - Callbacks
    2 
    3 Polysh uses specially crafted strings to communicate out of band data with
    4 remote shells. This includes detecting the shell prompt, and other events to
    5 detect.
    6 
    7 These strings are built and sent in two parts, the remote shell should send
    8 back the concatenation of these two strings to trigger the callback. This is
    9 to insure that the sending of the trigger to the remote shell does not
   10 trigger the callback.
   11 
   12 Example: The trigger FOOBAR could be split into FOO and BAR and sent as
   13          echo "FOO""BAR" so that the sent string does not contain FOOBAR.
   14 
   15 Copyright (c) 2006 Guillaume Chazarain <guichaz@gmail.com>
   16 Copyright (c) 2018 InnoGames GmbH
   17 """
   18 # This program is free software: you can redistribute it and/or modify
   19 # it under the terms of the GNU General Public License as published by
   20 # the Free Software Foundation, either version 2 of the License, or
   21 # (at your option) any later version.
   22 #
   23 # This program is distributed in the hope that it will be useful,
   24 # but WITHOUT ANY WARRANTY; without even the implied warranty of
   25 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   26 # GNU General Public License for more details.
   27 #
   28 # You should have received a copy of the GNU General Public License
   29 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
   30 
   31 import random
   32 from typing import Callable
   33 from typing import Tuple
   34 
   35 DIGITS_LETTERS = list(map(str, list(range(10)))) + \
   36     list(map(chr, list(range(ord('a'), ord('z') + 1)))) + \
   37     list(map(chr, list(range(ord('A'), ord('Z') + 1))))
   38 
   39 
   40 def random_string(length: int) -> str:
   41     def random_char() -> str:
   42         return DIGITS_LETTERS[random.randint(0, len(DIGITS_LETTERS) - 1)]
   43     return ''.join([random_char() for i in range(length)])
   44 
   45 
   46 COMMON_PREFIX = 'polysh-{}:'.format(random_string(5)).encode()
   47 NR_GENERATED_TRIGGERS = 0
   48 
   49 # {'random_string()': (function, repeat)}
   50 CALLBACKS = {}
   51 
   52 
   53 def add(name: bytes, function: Callable, repeat: bool) -> Tuple[bytes, bytes]:
   54     name = name.replace(b'/', b'_')
   55     global NR_GENERATED_TRIGGERS
   56     nr = NR_GENERATED_TRIGGERS
   57     NR_GENERATED_TRIGGERS += 1
   58     trigger = (COMMON_PREFIX + name + b':' + random_string(5).encode() + b':' +
   59                str(nr).encode() + b'/')
   60     CALLBACKS[trigger] = (function, repeat)
   61     trigger1 = trigger[:int(len(COMMON_PREFIX) / 2)]
   62     trigger2 = trigger[len(trigger1):]
   63     return trigger1, trigger2
   64 
   65 
   66 def any_in(data: bytes) -> bool:
   67     return COMMON_PREFIX in data
   68 
   69 
   70 def process(line: bytes) -> bool:
   71     start = line.find(COMMON_PREFIX)
   72     if start < 0:
   73         return False
   74 
   75     end = line.find(b'/', start) + 1
   76     if end <= 0:
   77         return False
   78 
   79     trigger = line[start:end]
   80     callback, repeat = CALLBACKS.get(trigger, (None, True))
   81     if not callback:
   82         return False
   83 
   84     if not repeat:
   85         del CALLBACKS[trigger]
   86 
   87     callback(line[end:].strip())
   88     return True