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 import traceback
  11 from collections import namedtuple
  12
  13 tuerSock = "/run/tuer.sock"
  14
  15 # use a histfile
  16 histfile = os.path.join(os.path.expanduser("~"), ".tyshellhist")
  17 try:
  18     readline.read_history_file(histfile)
  19 except IOError:
  20     pass
  21 import atexit
  22 atexit.register(readline.write_history_file, histfile)
  23
  24 # available commands
  25 def helpcmd(c):
  26         if (len(c) > 1):
  27                 print(commands.get(c[1],(None,'Can\'t find help for command %s'%(c[1]))).helpstring)
  28         else:
  29                 print("Available commands: %s" % ", ".join(sorted(commands.keys())))
  30                 print("Use 'help command' to get more information on the command 'command'")
  31
  32 def extcmd(cmd):
  33         def run(c):
  34                 ret = subprocess.call(cmd)
  35                 if ret != 0:
  36                         print("Command returned non-zero exit statis %d" % ret)
  37         return run
  38
  39 def sendcmd(addr, cmd):
  40         def run(c):
  41                 print("206 Sending command %s..." % (cmd))
  42                 s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
  43                 s.connect(addr)
  44                 s.settimeout(60.0)
  45                 s.send(cmd.encode())
  46                 while True:
  47                         data = s.recv(256)
  48                         if not len(data): break
  49                         print(data.decode('utf-8'))
  50                 s.close()
  51         return run
  52
  53 def exitcmd(c):
  54         print("Bye")
  55         return True
  56
  57 def whocmd(c):
  58         for n in grp.getgrnam("tuer").gr_mem:
  59                 p = pwd.getpwnam(n)
  60                 print (p.pw_name, " - ", p.pw_gecos)
  61
  62 def alias (cmds, aliases):
  63         for newname, oldname in aliases.items():
  64                 cmds[newname] = cmds[oldname]
  65         return cmds
  66
  67 CmdEntry = namedtuple('CmdEntry','function helpstring')
  68
  69 commands = alias({
  70         'exit': CmdEntry(exitcmd, 'Quits this shell'),
  71         'help': CmdEntry(helpcmd, 'Helps you getting to know the available commands'),
  72         'unlock': CmdEntry(sendcmd(tuerSock, 'unlock'), 'Will try to unlock the apartment door'),
  73         'buzz': CmdEntry(sendcmd(tuerSock, 'buzz'), 'Will buzz the buzzer for the street door'),
  74         'who': CmdEntry(whocmd, 'Shows the list of people, who are allowed to control this system'),
  75 },{
  76         # aliases
  77         'open': 'unlock',
  78 })
  79
  80 def complete_command(cmd):
  81         '''returns a list of commands (as strings) starting with cmd'''
  82         return list(filter(lambda x: x.startswith(cmd), commands.keys()))
  83 readline.set_completer(lambda cmd, num: (complete_command(cmd)+[None])[num]) # wrap complete_command for readline's weird completer API
  84 readline.parse_and_bind("tab: complete") # run completion on tab
  85
  86 # input loop
  87 print("Welcome to tyshell. Use help to see what you can do.")
  88 while True:
  89         try:
  90                 command = input("$ ")
  91         except EOFError:
  92                 print()
  93                 break
  94         command = shlex.split(command)
  95         if not len(command): continue
  96         # find suiting commands
  97         if command[0] in commands: # needed in case a complete command is a prefix of another one
  98                 cmdoptions = [command[0]]
  99         else:
 100                 cmdoptions = complete_command(command[0])
 101         # check how many we found
 102         if len(cmdoptions) == 0: # no commands fit prefix
 103                 print("Command %s not found. Use help." % command[0])
 104         elif len(cmdoptions) == 1: # exactly one command fits (prefix)
 105                 try:
 106                         res = commands[cmdoptions[0]].function(command)
 107                         if res: break
 108                 except Exception as e:
 109                         print("Error while executing %s: %s" % (command[0], str(e)))
 110                         #print(traceback.format_exc())
 111         else: # multiple commands fit the prefix
 112                 print("Ambiguous command prefix, please choose one of the following:")
 113                 print("\t", " ".join(cmdoptions))
 114                 # TODO: put current "command[0]" into the shell for the next command, but such that it is deletable with backspace
 115