Created
May 23, 2013 18:26
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"""Utilities to get a password and/or the current user name. | |
getpass(prompt[, stream]) - Prompt for a password, with echo turned off. | |
getuser() - Get the user name from the environment or password database. | |
GetPassWarning - This UserWarning is issued when getpass() cannot prevent | |
echoing of the password contents while reading. | |
On Windows, the msvcrt module will be used. | |
On the Mac EasyDialogs.AskPassword is used, if available. | |
""" | |
# Authors: Piers Lauder (original) | |
# Guido van Rossum (Windows support and cleanup) | |
# Gregory P. Smith (tty support & GetPassWarning) | |
import os, sys, warnings | |
__all__ = ["getpass","getuser","GetPassWarning"] | |
class GetPassWarning(UserWarning): pass | |
def unix_getpass(prompt='Password: ', stream=None): | |
"""Prompt for a password, with echo turned off. | |
Args: | |
prompt: Written on stream to ask for the input. Default: 'Password: ' | |
stream: A writable file object to display the prompt. Defaults to | |
the tty. If no tty is available defaults to sys.stderr. | |
Returns: | |
The seKr3t input. | |
Raises: | |
EOFError: If our input tty or stdin was closed. | |
GetPassWarning: When we were unable to turn echo off on the input. | |
Always restores terminal settings before returning. | |
""" | |
fd = None | |
tty = None | |
try: | |
# Always try reading and writing directly on the tty first. | |
fd = os.open('/dev/tty', os.O_RDWR|os.O_NOCTTY) | |
tty = os.fdopen(fd, 'w+', 1) | |
input = tty | |
if not stream: | |
stream = tty | |
except EnvironmentError, e: | |
# If that fails, see if stdin can be controlled. | |
try: | |
fd = sys.stdin.fileno() | |
except (AttributeError, ValueError): | |
passwd = fallback_getpass(prompt, stream) | |
input = sys.stdin | |
if not stream: | |
stream = sys.stderr | |
if fd is not None: | |
passwd = None | |
try: | |
old = termios.tcgetattr(fd) # a copy to save | |
new = old[:] | |
new[3] &= ~termios.ECHO # 3 == 'lflags' | |
tcsetattr_flags = termios.TCSAFLUSH | |
if hasattr(termios, 'TCSASOFT'): | |
tcsetattr_flags |= termios.TCSASOFT | |
try: | |
termios.tcsetattr(fd, tcsetattr_flags, new) | |
passwd = _raw_input(prompt, stream, input=input) | |
finally: | |
termios.tcsetattr(fd, tcsetattr_flags, old) | |
stream.flush() # issue7208 | |
except termios.error, e: | |
if passwd is not None: | |
# _raw_input succeeded. The final tcsetattr failed. Reraise | |
# instead of leaving the terminal in an unknown state. | |
raise | |
# We can't control the tty or stdin. Give up and use normal IO. | |
# fallback_getpass() raises an appropriate warning. | |
del input, tty # clean up unused file objects before blocking | |
passwd = fallback_getpass(prompt, stream) | |
stream.write('\n') | |
return passwd | |
def win_getpass(prompt='Password: ', stream=None): | |
"""Prompt for password with echo off, using Windows getch().""" | |
if sys.stdin is not sys.__stdin__: | |
return fallback_getpass(prompt, stream) | |
import msvcrt | |
for c in prompt: | |
msvcrt.putch(c) | |
pw = "" | |
while 1: | |
c = msvcrt.getch() | |
if c == '\r' or c == '\n': | |
break | |
if c == '\003': | |
raise KeyboardInterrupt | |
if c == '\b': | |
pw = pw[:-1] | |
else: | |
pw = pw + c | |
msvcrt.putch('\r') | |
msvcrt.putch('\n') | |
return pw | |
def fallback_getpass(prompt='Password: ', stream=None): | |
warnings.warn("Can not control echo on the terminal.", GetPassWarning, | |
stacklevel=2) | |
if not stream: | |
stream = sys.stderr | |
print >>stream, "Warning: Password input may be echoed." | |
return _raw_input(prompt, stream) | |
def _raw_input(prompt="", stream=None, input=None): | |
# A raw_input() replacement that doesn't save the string in the | |
# GNU readline history. | |
if not stream: | |
stream = sys.stderr | |
if not input: | |
input = sys.stdin | |
prompt = str(prompt) | |
if prompt: | |
stream.write(prompt) | |
stream.flush() | |
# NOTE: The Python C API calls flockfile() (and unlock) during readline. | |
line = input.readline() | |
if not line: | |
raise EOFError | |
if line[-1] == '\n': | |
line = line[:-1] | |
return line | |
def getuser(): | |
"""Get the username from the environment or password database. | |
First try various environment variables, then the password | |
database. This works on Windows as long as USERNAME is set. | |
""" | |
import os | |
for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'): | |
user = os.environ.get(name) | |
if user: | |
return user | |
# If this fails, the exception will "explain" why | |
import pwd | |
return pwd.getpwuid(os.getuid())[0] | |
# Bind the name getpass to the appropriate function | |
try: | |
import termios | |
# it's possible there is an incompatible termios from the | |
# McMillan Installer, make sure we have a UNIX-compatible termios | |
termios.tcgetattr, termios.tcsetattr | |
except (ImportError, AttributeError): | |
try: | |
import msvcrt | |
except ImportError: | |
try: | |
from EasyDialogs import AskPassword | |
except ImportError: | |
getpass = fallback_getpass | |
else: | |
getpass = AskPassword | |
else: | |
getpass = win_getpass | |
else: | |
getpass = unix_getpass |
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