tyshell

   1 #!/usr/bin/python3
   2 import os
   3 import readline
   4 import shlex
   5 import sys
   6 import subprocess
   7 import socket
   8 import pwd
   9 import grp
  10
  11 tuerSock = "/run/tuer.sock"
  12
  13 # use a histfile
  14 histfile = os.path.join(os.path.expanduser("~"), ".tyshellhist")
  15 try:
  16     readline.read_history_file(histfile)
  17 except IOError:
  18     pass
  19 import atexit
  20 atexit.register(readline.write_history_file, histfile)
  21
  22 # available commands
  23 def helpcmd(c):
  24         if (len(c) > 1):
  25                 print(commands.get(c[1],(None,'Can\'t find help for command %s'%(c[1])))[1])
  26         else:
  27                 print("Available commands: %s" % ", ".join(sorted(commands.keys())))
  28                 print("Use 'help command' to get more information on the command 'command'")
  29
  30 def extcmd(cmd):
  31         def run(c):
  32                 ret = subprocess.call(cmd)
  33                 if ret != 0:
  34                         print("Command returned non-zero exit statis %d" % ret)
  35         return run
  36
  37 def sendcmd(addr, cmd):
  38         def run(c):
  39                 print("206 Sending command %s..." % (cmd))
  40                 s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
  41                 s.connect(addr)
  42                 s.settimeout(60.0)
  43                 s.send(cmd.encode())
  44                 data = s.recv(256)
  45                 s.close()
  46                 print(data.decode('utf-8'))
  47         return run
  48
  49 def exitcmd(c):
  50         print("Bye")
  51         return True
  52
  53 def whocmd(c):
  54         for n in grp.getgrnam("tuer").gr_mem:
  55                 p = pwd.getpwnam(n)
  56                 print (p.pw_name, " - ", p.pw_gecos)
  57
  58 def alias (cmds, aliases):
  59         for newname, oldname in aliases.items():
  60                 cmds[newname] = cmds[oldname]
  61         return cmds
  62
  63 commands = alias({
  64         'exit': (exitcmd, 'Quits this shell'),
  65         'help': (helpcmd, 'Helps you getting to know the available commands'),
  66         'open': (sendcmd(tuerSock, 'unlock'), 'Will try to unlock the apartment door'),
  67         'buzz': (sendcmd(tuerSock, 'buzz'), 'Will buzz the buzzer for the street door'),
  68         'who': (whocmd, 'Shows the list of people, who are allowed to control this system'),
  69 },{
  70         # aliases
  71         'unlock': 'open',
  72 })
  73
  74 def complete_command(cmd):
  75         '''returns a list of commands (as strings) starting with cmd'''
  76         return list(filter(lambda x: x.startswith(cmd), commands.keys()))
  77 readline.set_completer(lambda cmd, num: (complete_command(cmd)+[None])[num]) # wrap complete_command for readline's weird completer API
  78 readline.parse_and_bind("tab: complete") # run completion on tab
  79
  80 # input loop
  81 print("Welcome to tyshell. Use help to see what you can do.")
  82 while True:
  83         try:
  84                 command = input("$ ")
  85         except EOFError:
  86                 print()
  87                 break
  88         command = shlex.split(command)
  89         if not len(command): continue
  90         # find suiting commands
  91         if command[0] in commands: # needed in case a complete command is a prefix of another one
  92                 cmdoptions = [command[0]]
  93         else:
  94                 cmdoptions = complete_command(command[0])
  95         # check how many we found
  96         if len(cmdoptions) == 0: # no commands fit prefix
  97                 print("Command %s not found. Use help." % command[0])
  98         elif len(cmdoptions) == 1: # exactly one command fits (prefix)
  99                 try:
 100                         res = commands[cmdoptions[0]][0](command)
 101                         if res: break
 102                 except Exception as e:
 103                         print("Error while executing %s: %s" % (command[0], str(e)))
 104         else: # multiple commands fit the prefix
 105                 print("Ambiguous command prefix, please choose one of the following:")
 106                 print("\t", " ".join(cmdoptions))
 107                 # TODO: put current "command[0]" into the shell for the next command, but such that it is deletable with backspace
 108