"""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. """ # Authors: Piers Lauder (original) # Guido van Rossum (Windows support and cleanup) # Gregory P. Smith (tty support & GetPassWarning) import contextlib import io import os import sys import 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. """ passwd = None with contextlib.ExitStack() as stack: try: # Always try reading and writing directly on the tty first. fd = os.open('/dev/tty', os.O_RDWR|os.O_NOCTTY) tty = io.FileIO(fd, 'w+') stack.enter_context(tty) input = io.TextIOWrapper(tty) stack.enter_context(input) if not stream: stream = input except OSError as e: # If that fails, see if stdin can be controlled. stack.close() try: fd = sys.stdin.fileno() except (AttributeError, ValueError): fd = None passwd = fallback_getpass(prompt, stream) input = sys.stdin if not stream: stream = sys.stderr if fd is not 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: 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. if stream is not input: # clean up unused file objects before blocking stack.close() 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) for c in prompt: msvcrt.putwch(c) pw = "" while 1: c = msvcrt.getwch() if c == '\r' or c == '\n': break if c == '\003': raise KeyboardInterrupt if c == '\b': pw = pw[:-1] else: pw = pw + c msvcrt.putwch('\r') msvcrt.putwch('\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("Warning: Password input may be echoed.", file=stream) return _raw_input(prompt, stream) def _raw_input(prompt="", stream=None, input=None): # This 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: try: stream.write(prompt) except UnicodeEncodeError: # Use replace error handler to get as much as possible printed. prompt = prompt.encode(stream.encoding, 'replace') prompt = prompt.decode(stream.encoding) 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. """ 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: getpass = fallback_getpass else: getpass = win_getpass else: getpass = unix_getpass