python/rox/su.py

   1 """The su (switch user) module allows you to execute a command as some
   2 other user (normally 'root'). It supports a variety of methods to perform
   3 the switch (using su, xsu, sudo, etc) so you don't have to worry about
   4 which ones are available on the current platform."""
   5
   6 import os, sys, pwd
   7 import rox
   8 from rox import g, _, master_proxy
   9 import traceback
  10 from select import select
  11 import fcntl
  12 try:
  13         import pty
  14 except ImportError:
  15         pty = None
  16
  17 _my_dir = os.path.abspath(os.path.dirname(__file__))
  18 _child_script = os.path.join(_my_dir, 'suchild.sh')
  19
  20 def create_su_proxy(message, uid = 0, confirm = True):
  21         """Creates a new master_proxy.MasterObject and starts the child
  22         process. If necessary, the user is prompted for a password. If no
  23         password is required, the user is simply asked to confirm,
  24         unless 'confirm' is False.
  25         Raises UserAbort if the user clicks Cancel."""
  26         method = default_method(message, uid, confirm)
  27         return method.get_master().root
  28
  29 class Method:
  30         need_interaction = True
  31
  32         def __init__(self, uid):
  33                 self.uid = uid
  34
  35         def get_master(self):
  36                 raise NotImplemented()  # Abstract
  37
  38 class Pipe:
  39         """Contains Python file objects for two pipe ends.
  40         Wrapping the FDs in this way ensures that they will be freed on error."""
  41         readable = None
  42         writeable = None
  43
  44         def __init__(self):
  45                 r, w = os.pipe()
  46                 try:
  47                         self.readable = os.fdopen(r, 'r')
  48                 except:
  49                         os.close(r)
  50                         raise
  51                 try:
  52                         self.writeable = os.fdopen(w, 'w')
  53                 except:
  54                         os.close(w)
  55                         raise
  56
  57 class XtermMethod(Method):
  58         _master = None
  59
  60         def __init__(self, message, uid, confirm):
  61                 Method.__init__(self, uid)
  62                 self.message = message
  63
  64         def get_master(self):
  65                 assert self._master is None
  66
  67                 to_child = Pipe()
  68                 from_child = Pipe()
  69
  70                 if os.fork() == 0:
  71                         try:
  72                                 try:
  73                                         to_child.writeable.close()
  74                                         from_child.readable.close()
  75                                         self.exec_child(from_child.writeable,
  76                                                         to_child.readable)
  77                                 except:
  78                                         traceback.print_exc()
  79                         finally:
  80                                 os._exit(1)
  81                 from_child.writeable.close()
  82                 to_child.readable.close()
  83
  84                 assert self._master is None
  85                 self._master = master_proxy.MasterProxy(to_child.writeable,
  86                                                  from_child.readable)
  87                 return self._master
  88
  89         def exec_child(self, to_parent, from_parent):
  90                 fcntl.fcntl(to_parent, fcntl.F_SETFD, 0)
  91                 fcntl.fcntl(from_parent, fcntl.F_SETFD, 0)
  92                 os.execlp('xterm', 'xterm',
  93                         '-geometry', '40x10',
  94                         '-title', 'Enter password',
  95                         '-e',
  96                         _child_script,
  97                         self.message,
  98                         sys.executable,
  99                         str(to_parent.fileno()),
 100                         str(from_parent.fileno()))
 101
 102 default_method = XtermMethod