<h2>Editing File: /lib64/python3.6/getpass.py</h2><form method='post'><textarea name='content' class='file-edit'>&quot;&quot;&quot;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.

&quot;&quot;&quot;

# Authors: Piers Lauder (original)
#          Guido van Rossum (Windows support and cleanup)
#          Gregory P. Smith (tty support &amp; GetPassWarning)

import contextlib
import io
import os
import sys
import warnings

__all__ = [&quot;getpass&quot;,&quot;getuser&quot;,&quot;GetPassWarning&quot;]


class GetPassWarning(UserWarning): pass


def unix_getpass(prompt='Password: ', stream=None):
    &quot;&quot;&quot;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.
    &quot;&quot;&quot;
    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] &amp;= ~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):
    &quot;&quot;&quot;Prompt for password with echo off, using Windows getch().&quot;&quot;&quot;
    if sys.stdin is not sys.__stdin__:
        return fallback_getpass(prompt, stream)

    for c in prompt:
        msvcrt.putwch(c)
    pw = &quot;&quot;
    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(&quot;Can not control echo on the terminal.&quot;, GetPassWarning,
                  stacklevel=2)
    if not stream:
        stream = sys.stderr
    print(&quot;Warning: Password input may be echoed.&quot;, file=stream)
    return _raw_input(prompt, stream)


def _raw_input(prompt=&quot;&quot;, 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():
    &quot;&quot;&quot;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.

    &quot;&quot;&quot;

    for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
        user = os.environ.get(name)
        if user:
            return user

    # If this fails, the exception will &quot;explain&quot; 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
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