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 Authors: Piers Lauder (original)
   7          Guido van Rossum (Windows support and cleanup)
   8 """
   9
  10
  11 def getpass(prompt='Password: '):
  12         """Prompt for a password, with echo turned off.
  13
  14         Restore terminal settings at end.
  15
  16         On Windows, this calls win_getpass(prompt) which uses the
  17         msvcrt module to get the same effect.
  18
  19         On the Mac EasyDialogs.AskPassword is used, if available.
  20
  21         """
  22
  23         import sys
  24         try:
  25                 fd = sys.stdin.fileno()
  26         except:
  27                 return default_getpass(prompt)
  28         try:
  29                 import termios, TERMIOS
  30         except ImportError:
  31                 try:
  32                         import msvcrt
  33                 except ImportError:
  34                         try:
  35                                 from EasyDialogs import AskPassword
  36                         except ImportError:
  37                                 return default_getpass(prompt)
  38                         else:
  39                                 return AskPassword(prompt)
  40                 else:
  41                         return win_getpass(prompt)
  42
  43         old = termios.tcgetattr(fd)     # a copy to save
  44         new = old[:]
  45
  46         new[3] = new[3] & ~TERMIOS.ECHO # 3 == 'lflags'
  47         try:
  48                 termios.tcsetattr(fd, TERMIOS.TCSADRAIN, new)
  49                 passwd = _raw_input(prompt)
  50         finally:
  51                 termios.tcsetattr(fd, TERMIOS.TCSADRAIN, old)
  52
  53         sys.stdout.write('\n')
  54         return passwd
  55
  56
  57 def win_getpass(prompt='Password: '):
  58         """Prompt for password with echo off, using Windows getch()."""
  59         import msvcrt
  60         for c in prompt:
  61                 msvcrt.putch(c)
  62         pw = ""
  63         while 1:
  64                 c = msvcrt.getch()
  65                 if c == '\r' or c == '\n':
  66                         break
  67                 if c == '\003':
  68                         raise KeyboardInterrupt
  69                 if c == '\b':
  70                         pw = pw[:-1]
  71                 else:
  72                         pw = pw + c
  73         msvcrt.putch('\r')
  74         msvcrt.putch('\n')
  75         return pw
  76
  77
  78 def default_getpass(prompt='Password: '):
  79         return _raw_input(prompt)
  80
  81
  82 def _raw_input(prompt=""):
  83         # A raw_input() replacement that doesn't save the string in the
  84         # GNU readline history.
  85         import sys
  86         prompt = str(prompt)
  87         if prompt:
  88                 sys.stdout.write(prompt)
  89         line = sys.stdin.readline()
  90         if not line:
  91                 raise EOFError
  92         if line[-1] == '\n':
  93                 line = line[:-1]
  94         return line
  95
  96
  97 def getuser():
  98         """Get the username from the environment or password database.
  99
 100         First try various environment variables, then the password
 101         database.  This works on Windows as long as USERNAME is set.
 102
 103         """
 104
 105         import os
 106
 107         for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
 108                 user = os.environ.get(name)
 109                 if user:
 110                         return user
 111
 112         # If this fails, the exception will "explain" why
 113         import pwd
 114         return pwd.getpwuid(os.getuid())[0]