Lib/getpass.py

   1 """Utilities to get a password and/or the current user name.
   2
   3 getpass(prompt) - prompt for a password, with echo turned off
   4 getuser() - get the user name from the environment or password database
   5
   6 On Windows, the msvcrt module will be used.
   7 On the Mac EasyDialogs.AskPassword is used, if available.
   8
   9 """
  10
  11 # Authors: Piers Lauder (original)
  12 #          Guido van Rossum (Windows support and cleanup)
  13
  14 import sys
  15
  16 __all__ = ["getpass","getuser"]
  17
  18 def unix_getpass(prompt='Password: ', stream=None):
  19     """Prompt for a password, with echo turned off.
  20     The prompt is written on stream, by default stdout.
  21
  22     Restore terminal settings at end.
  23     """
  24     if stream is None:
  25         stream = sys.stdout
  26
  27     try:
  28         fd = sys.stdin.fileno()
  29     except:
  30         return default_getpass(prompt)
  31
  32     old = termios.tcgetattr(fd)     # a copy to save
  33     new = old[:]
  34
  35     new[3] = new[3] & ~termios.ECHO # 3 == 'lflags'
  36     try:
  37         termios.tcsetattr(fd, termios.TCSADRAIN, new)
  38         passwd = _raw_input(prompt, stream)
  39     finally:
  40         termios.tcsetattr(fd, termios.TCSADRAIN, old)
  41
  42     stream.write('\n')
  43     return passwd
  44
  45
  46 def win_getpass(prompt='Password: ', stream=None):
  47     """Prompt for password with echo off, using Windows getch()."""
  48     if sys.stdin is not sys.__stdin__:
  49         return default_getpass(prompt, stream)
  50     import msvcrt
  51     for c in prompt:
  52         msvcrt.putch(c)
  53     pw = ""
  54     while 1:
  55         c = msvcrt.getch()
  56         if c == '\r' or c == '\n':
  57             break
  58         if c == '\003':
  59             raise KeyboardInterrupt
  60         if c == '\b':
  61             pw = pw[:-1]
  62         else:
  63             pw = pw + c
  64     msvcrt.putch('\r')
  65     msvcrt.putch('\n')
  66     return pw
  67
  68
  69 def default_getpass(prompt='Password: ', stream=None):
  70     print >>sys.stderr, "Warning: Problem with getpass. Passwords may be echoed."
  71     return _raw_input(prompt, stream)
  72
  73
  74 def _raw_input(prompt="", stream=None):
  75     # A raw_input() replacement that doesn't save the string in the
  76     # GNU readline history.
  77     if stream is None:
  78         stream = sys.stdout
  79     prompt = str(prompt)
  80     if prompt:
  81         stream.write(prompt)
  82     line = sys.stdin.readline()
  83     if not line:
  84         raise EOFError
  85     if line[-1] == '\n':
  86         line = line[:-1]
  87     return line
  88
  89
  90 def getuser():
  91     """Get the username from the environment or password database.
  92
  93     First try various environment variables, then the password
  94     database.  This works on Windows as long as USERNAME is set.
  95
  96     """
  97
  98     import os
  99
 100     for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
 101         user = os.environ.get(name)
 102         if user:
 103             return user
 104
 105     # If this fails, the exception will "explain" why
 106     import pwd
 107     return pwd.getpwuid(os.getuid())[0]
 108
 109 # Bind the name getpass to the appropriate function
 110 try:
 111     import termios
 112     # it's possible there is an incompatible termios from the
 113     # McMillan Installer, make sure we have a UNIX-compatible termios
 114     termios.tcgetattr, termios.tcsetattr
 115 except (ImportError, AttributeError):
 116     try:
 117         import msvcrt
 118     except ImportError:
 119         try:
 120             from EasyDialogs import AskPassword
 121         except ImportError:
 122             getpass = default_getpass
 123         else:
 124             getpass = AskPassword
 125     else:
 126         getpass = win_getpass
 127 else:
 128     getpass = unix_getpass