/* Copyright (C) 1992-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>

#include <stdio_ext.h>

#include <string.h>		/* For string function builtin redirect.  */

#include <termios.h>

#include <unistd.h>

#include <wchar.h>

#define flockfile(s) _IO_flockfile (s)

#define funlockfile(s) _IO_funlockfile (s)

#include <libc-lock.h>

/* It is desirable to use this bit on systems that have it.

   The only bit of terminal state we want to twiddle is echoing, which is

   done in software; there is no need to change the state of the terminal

   hardware.  */

#ifndef TCSASOFT

#define TCSASOFT 0

#endif

static void

call_fclose (void *arg)

{

  if (arg != NULL)

    fclose (arg);

}

char *

getpass (const char *prompt)

{

  FILE *in, *out;

  struct termios s, t;

  int tty_changed;

  static char *buf;

  static size_t bufsize;

  ssize_t nread;

  /* Try to write to and read from the terminal if we can.

     If we can't open the terminal, use stderr and stdin.  */

  in = fopen ("/dev/tty", "w+ce");

  if (in == NULL)

    {

      in = stdin;

      out = stderr;

    }

  else

    {

      /* We do the locking ourselves.  */

      __fsetlocking (in, FSETLOCKING_BYCALLER);

      out = in;

    }

  /* Make sure the stream we opened is closed even if the thread is

     canceled.  */

  __libc_cleanup_push (call_fclose, in == out ? in : NULL);

  flockfile (out);

  /* Turn echoing off if it is on now.  */

  if (__tcgetattr (fileno (in), &t) == 0)

    {

      /* Save the old one. */

      s = t;

      /* Tricky, tricky. */

      t.c_lflag &= ~(ECHO|ISIG);

      tty_changed = (tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &t) == 0);

    }

  else

    tty_changed = 0;

  /* Write the prompt.  */

  __fxprintf (out, "%s", prompt);

  __fflush_unlocked (out);

  /* Read the password.  */

  nread = __getline (&buf, &bufsize, in);

  if (buf != NULL)

    {

      if (nread < 0)

	buf[0] = '\0';

      else if (buf[nread - 1] == '\n')

	{

	  /* Remove the newline.  */

	  buf[nread - 1] = '\0';

	  if (tty_changed)

	    /* Write the newline that was not echoed.  */

	    __fxprintf (out, "\n");

	}

    }

  /* Restore the original setting.  */

  if (tty_changed)

    (void) tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &s);

  funlockfile (out);

  __libc_cleanup_pop (0);

  if (in != stdin)

    /* We opened the terminal; now close it.  */

    fclose (in);

  return buf;

}