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 def unix_getpass(prompt='Password: '):
  17         """Prompt for a password, with echo turned off.
  18
  19         Restore terminal settings at end.
  20         """
  21
  22         try:
  23                 fd = sys.stdin.fileno()
  24         except:
  25                 return default_getpass(prompt)
  26
  27         getpass = default_getpass
  28         old = termios.tcgetattr(fd)     # a copy to save
  29         new = old[:]
  30
  31         new[3] = new[3] & ~TERMIOS.ECHO # 3 == 'lflags'
  32         try:
  33                 termios.tcsetattr(fd, TERMIOS.TCSADRAIN, new)
  34                 passwd = _raw_input(prompt)
  35         finally:
  36                 termios.tcsetattr(fd, TERMIOS.TCSADRAIN, old)
  37
  38         sys.stdout.write('\n')
  39         return passwd
  40
  41
  42 def win_getpass(prompt='Password: '):
  43         """Prompt for password with echo off, using Windows getch()."""
  44         import msvcrt
  45         for c in prompt:
  46                 msvcrt.putch(c)
  47         pw = ""
  48         while 1:
  49                 c = msvcrt.getch()
  50                 if c == '\r' or c == '\n':
  51                         break
  52                 if c == '\003':
  53                         raise KeyboardInterrupt
  54                 if c == '\b':
  55                         pw = pw[:-1]
  56                 else:
  57                         pw = pw + c
  58         msvcrt.putch('\r')
  59         msvcrt.putch('\n')
  60         return pw
  61
  62
  63 def default_getpass(prompt='Password: '):
  64         print "Warning: Problem with getpass. Passwords may be echoed."
  65         return _raw_input(prompt)
  66
  67
  68 def _raw_input(prompt=""):
  69         # A raw_input() replacement that doesn't save the string in the
  70         # GNU readline history.
  71         import sys
  72         prompt = str(prompt)
  73         if prompt:
  74                 sys.stdout.write(prompt)
  75         line = sys.stdin.readline()
  76         if not line:
  77                 raise EOFError
  78         if line[-1] == '\n':
  79                 line = line[:-1]
  80         return line
  81
  82
  83 def getuser():
  84         """Get the username from the environment or password database.
  85
  86         First try various environment variables, then the password
  87         database.  This works on Windows as long as USERNAME is set.
  88
  89         """
  90
  91         import os
  92
  93         for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
  94                 user = os.environ.get(name)
  95                 if user:
  96                         return user
  97
  98         # If this fails, the exception will "explain" why
  99         import pwd
 100         return pwd.getpwuid(os.getuid())[0]
 101
 102 # Bind the name getpass to the appropriate function
 103 try:
 104         import termios, TERMIOS
 105 except ImportError:
 106         try:
 107                 import msvcrt
 108         except ImportError:
 109                 try:
 110                         from EasyDialogs import AskPassword
 111                 except ImportError:
 112                         getpass = default_getpass
 113                 else:
 114                         getpass = AskPassword
 115         else:
 116                 getpass = win_getpass
 117 else:
 118         getpass = unix_getpass
 119