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 from collections import namedtuple
  11
  12 tuerSock = "/run/tuer.sock"
  13
  14 # use a histfile
  15 histfile = os.path.join(os.path.expanduser("~"), ".tyshellhist")
  16 try:
  17     readline.read_history_file(histfile)
  18 except IOError:
  19     pass
  20 import atexit
  21 atexit.register(readline.write_history_file, histfile)
  22
  23 # available commands
  24 def helpcmd(c):
  25         if (len(c) > 1):
  26                 print(commands.get(c[1],(None,'Can\'t find help for command %s'%(c[1]))).helpstring)
  27         else:
  28                 print("Available commands: %s" % ", ".join(sorted(commands.keys())))
  29                 print("Use 'help command' to get more information on the command 'command'")
  30
  31 def extcmd(cmd):
  32         def run(c):
  33                 ret = subprocess.call(cmd)
  34                 if ret != 0:
  35                         print("Command returned non-zero exit statis %d" % ret)
  36         return run
  37
  38 def sendcmd(addr, cmd):
  39         def run(c):
  40                 print("206 Sending command %s..." % (cmd))
  41                 s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
  42                 s.connect(addr)
  43                 s.settimeout(60.0)
  44                 s.send(cmd.encode())
  45                 data = s.recv(256)
  46                 s.close()
  47                 print(data.decode('utf-8'))
  48         return run
  49
  50 def exitcmd(c):
  51         print("Bye")
  52         return True
  53
  54 def whocmd(c):
  55         for n in grp.getgrnam("tuer").gr_mem:
  56                 p = pwd.getpwnam(n)
  57                 print (p.pw_name, " - ", p.pw_gecos)
  58
  59 def alias (cmds, aliases):
  60         for newname, oldname in aliases.items():
  61                 cmds[newname] = cmds[oldname]
  62         return cmds
  63
  64 CmdEntry = namedtuple('CmdEntry','function helpstring')
  65
  66 commands = alias({
  67         'exit': CmdEntry(exitcmd, 'Quits this shell'),
  68         'help': CmdEntry(helpcmd, 'Helps you getting to know the available commands'),
  69         'open': CmdEntry(sendcmd(tuerSock, 'unlock'), 'Will try to unlock the apartment door'),
  70         'buzz': CmdEntry(sendcmd(tuerSock, 'buzz'), 'Will buzz the buzzer for the street door'),
  71         'who': CmdEntry(whocmd, 'Shows the list of people, who are allowed to control this system'),
  72 },{
  73         # aliases
  74         'unlock': 'open',
  75 })
  76
  77 def complete_command(cmd):
  78         '''returns a list of commands (as strings) starting with cmd'''
  79         return list(filter(lambda x: x.startswith(cmd), commands.keys()))
  80 readline.set_completer(lambda cmd, num: (complete_command(cmd)+[None])[num]) # wrap complete_command for readline's weird completer API
  81 readline.parse_and_bind("tab: complete") # run completion on tab
  82
  83 # input loop
  84 print("Welcome to tyshell. Use help to see what you can do.")
  85 while True:
  86         try:
  87                 command = input("$ ")
  88         except EOFError:
  89                 print()
  90                 break
  91         command = shlex.split(command)
  92         if not len(command): continue
  93         # find suiting commands
  94         if command[0] in commands: # needed in case a complete command is a prefix of another one
  95                 cmdoptions = [command[0]]
  96         else:
  97                 cmdoptions = complete_command(command[0])
  98         # check how many we found
  99         if len(cmdoptions) == 0: # no commands fit prefix
 100                 print("Command %s not found. Use help." % command[0])
 101         elif len(cmdoptions) == 1: # exactly one command fits (prefix)
 102                 try:
 103                         res = commands[cmdoptions[0]].function(command)
 104                         if res: break
 105                 except Exception as e:
 106                         print("Error while executing %s: %s" % (command[0], str(e)))
 107         else: # multiple commands fit the prefix
 108                 print("Ambiguous command prefix, please choose one of the following:")
 109                 print("\t", " ".join(cmdoptions))
 110                 # TODO: put current "command[0]" into the shell for the next command, but such that it is deletable with backspace
 111