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: '):
  19     """Prompt for a password, with echo turned off.
  20
  21     Restore terminal settings at end.
  22     """
  23
  24     try:
  25         fd = sys.stdin.fileno()
  26     except:
  27         return default_getpass(prompt)
  28
  29     getpass = default_getpass
  30     old = termios.tcgetattr(fd)     # a copy to save
  31     new = old[:]
  32
  33     new[3] = new[3] & ~termios.ECHO # 3 == 'lflags'
  34     try:
  35         termios.tcsetattr(fd, termios.TCSADRAIN, new)
  36         passwd = _raw_input(prompt)
  37     finally:
  38         termios.tcsetattr(fd, termios.TCSADRAIN, old)
  39
  40     sys.stdout.write('\n')
  41     return passwd
  42
  43
  44 def win_getpass(prompt='Password: '):
  45     """Prompt for password with echo off, using Windows getch()."""
  46     import msvcrt
  47     for c in prompt:
  48         msvcrt.putch(c)
  49     pw = ""
  50     while 1:
  51         c = msvcrt.getch()
  52         if c == '\r' or c == '\n':
  53             break
  54         if c == '\003':
  55             raise KeyboardInterrupt
  56         if c == '\b':
  57             pw = pw[:-1]
  58         else:
  59             pw = pw + c
  60     msvcrt.putch('\r')
  61     msvcrt.putch('\n')
  62     return pw
  63
  64
  65 def default_getpass(prompt='Password: '):
  66     print "Warning: Problem with getpass. Passwords may be echoed."
  67     return _raw_input(prompt)
  68
  69
  70 def _raw_input(prompt=""):
  71     # A raw_input() replacement that doesn't save the string in the
  72     # GNU readline history.
  73     import sys
  74     prompt = str(prompt)
  75     if prompt:
  76         sys.stdout.write(prompt)
  77     line = sys.stdin.readline()
  78     if not line:
  79         raise EOFError
  80     if line[-1] == '\n':
  81         line = line[:-1]
  82     return line
  83
  84
  85 def getuser():
  86     """Get the username from the environment or password database.
  87
  88     First try various environment variables, then the password
  89     database.  This works on Windows as long as USERNAME is set.
  90
  91     """
  92
  93     import os
  94
  95     for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
  96         user = os.environ.get(name)
  97         if user:
  98             return user
  99
 100     # If this fails, the exception will "explain" why
 101     import pwd
 102     return pwd.getpwuid(os.getuid())[0]
 103
 104 # Bind the name getpass to the appropriate function
 105 try:
 106     import termios
 107 except ImportError:
 108     try:
 109         import msvcrt
 110     except ImportError:
 111         try:
 112             from EasyDialogs import AskPassword
 113         except ImportError:
 114             getpass = default_getpass
 115         else:
 116             getpass = AskPassword
 117     else:
 118         getpass = win_getpass
 119 else:
 120     getpass = unix_getpass