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                 data = s.recv(256)
  47                 s.close()
  48                 print(data.decode('utf-8'))
  49         return run
  50
  51 def exitcmd(c):
  52         print("Bye")
  53         return True
  54
  55 def whocmd(c):
  56         for n in grp.getgrnam("tuer").gr_mem:
  57                 p = pwd.getpwnam(n)
  58                 print (p.pw_name, " - ", p.pw_gecos)
  59
  60 def alias (cmds, aliases):
  61         for newname, oldname in aliases.items():
  62                 cmds[newname] = cmds[oldname]
  63         return cmds
  64
  65 CmdEntry = namedtuple('CmdEntry','function helpstring')
  66
  67 commands = alias({
  68         'exit': CmdEntry(exitcmd, 'Quits this shell'),
  69         'help': CmdEntry(helpcmd, 'Helps you getting to know the available commands'),
  70         'unlock': CmdEntry(sendcmd(tuerSock, 'unlock'), 'Will try to unlock the apartment door'),
  71         'buzz': CmdEntry(sendcmd(tuerSock, 'buzz'), 'Will buzz the buzzer for the street door'),
  72         'who': CmdEntry(whocmd, 'Shows the list of people, who are allowed to control this system'),
  73 },{
  74         # aliases
  75         'open': 'unlock',
  76 })
  77
  78 def complete_command(cmd):
  79         '''returns a list of commands (as strings) starting with cmd'''
  80         return list(filter(lambda x: x.startswith(cmd), commands.keys()))
  81 readline.set_completer(lambda cmd, num: (complete_command(cmd)+[None])[num]) # wrap complete_command for readline's weird completer API
  82 readline.parse_and_bind("tab: complete") # run completion on tab
  83
  84 # input loop
  85 print("Welcome to tyshell. Use help to see what you can do.")
  86 while True:
  87         try:
  88                 command = input("$ ")
  89         except EOFError:
  90                 print()
  91                 break
  92         command = shlex.split(command)
  93         if not len(command): continue
  94         # find suiting commands
  95         if command[0] in commands: # needed in case a complete command is a prefix of another one
  96                 cmdoptions = [command[0]]
  97         else:
  98                 cmdoptions = complete_command(command[0])
  99         # check how many we found
 100         if len(cmdoptions) == 0: # no commands fit prefix
 101                 print("Command %s not found. Use help." % command[0])
 102         elif len(cmdoptions) == 1: # exactly one command fits (prefix)
 103                 try:
 104                         res = commands[cmdoptions[0]].function(command)
 105                         if res: break
 106                 except Exception as e:
 107                         print("Error while executing %s: %s" % (command[0], str(e)))
 108                         #print(traceback.format_exc())
 109         else: # multiple commands fit the prefix
 110                 print("Ambiguous command prefix, please choose one of the following:")
 111                 print("\t", " ".join(cmdoptions))
 112                 # TODO: put current "command[0]" into the shell for the next command, but such that it is deletable with backspace
 113