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