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     old = termios.tcgetattr(fd)     # a copy to save
  30     new = old[:]
  31
  32     new[3] = new[3] & ~termios.ECHO # 3 == 'lflags'
  33     try:
  34         termios.tcsetattr(fd, termios.TCSADRAIN, new)
  35         passwd = _raw_input(prompt)
  36     finally:
  37         termios.tcsetattr(fd, termios.TCSADRAIN, old)
  38
  39     sys.stdout.write('\n')
  40     return passwd
  41
  42
  43 def win_getpass(prompt='Password: '):
  44     """Prompt for password with echo off, using Windows getch()."""
  45     if sys.stdin is not sys.__stdin__:
  46         return default_getpass(prompt)
  47     import msvcrt
  48     for c in prompt:
  49         msvcrt.putch(c)
  50     pw = ""
  51     while 1:
  52         c = msvcrt.getch()
  53         if c == '\r' or c == '\n':
  54             break
  55         if c == '\003':
  56             raise KeyboardInterrupt
  57         if c == '\b':
  58             pw = pw[:-1]
  59         else:
  60             pw = pw + c
  61     msvcrt.putch('\r')
  62     msvcrt.putch('\n')
  63     return pw
  64
  65
  66 def default_getpass(prompt='Password: '):
  67     print "Warning: Problem with getpass. Passwords may be echoed."
  68     return _raw_input(prompt)
  69
  70
  71 def _raw_input(prompt=""):
  72     # A raw_input() replacement that doesn't save the string in the
  73     # GNU readline history.
  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     # it's possible there is an incompatible termios from the
 108     # McMillan Installer, make sure we have a UNIX-compatible termios
 109     termios.tcgetattr, termios.tcsetattr
 110 except (ImportError, AttributeError):
 111     try:
 112         import msvcrt
 113     except ImportError:
 114         try:
 115             from EasyDialogs import AskPassword
 116         except ImportError:
 117             getpass = default_getpass
 118         else:
 119             getpass = AskPassword
 120     else:
 121         getpass = win_getpass
 122 else:
 123     getpass = unix_getpass