/* Copyright (C) 1992-2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License along

   with this program; if not, see <https://www.gnu.org/licenses/>.  */

#ifndef _LIBC

# include <config.h>

#endif

#include "getpass.h"

#include <stdio.h>

#if !(defined _WIN32 && !defined __CYGWIN__)

# include <stdbool.h>

# if HAVE_DECL___FSETLOCKING && HAVE___FSETLOCKING

#  if HAVE_STDIO_EXT_H

#   include <stdio_ext.h>

#  endif

# else

#  define __fsetlocking(stream, type)    /* empty */

# endif

# if HAVE_TERMIOS_H

#  include <termios.h>

# endif

# if USE_UNLOCKED_IO

#  include "unlocked-io.h"

# else

#  if !HAVE_DECL_FFLUSH_UNLOCKED

#   undef fflush_unlocked

#   define fflush_unlocked(x) fflush (x)

#  endif

#  if !HAVE_DECL_FLOCKFILE

#   undef flockfile

#   define flockfile(x) ((void) 0)

#  endif

#  if !HAVE_DECL_FUNLOCKFILE

#   undef funlockfile

#   define funlockfile(x) ((void) 0)

#  endif

#  if !HAVE_DECL_FPUTS_UNLOCKED

#   undef fputs_unlocked

#   define fputs_unlocked(str,stream) fputs (str, stream)

#  endif

#  if !HAVE_DECL_PUTC_UNLOCKED

#   undef putc_unlocked

#   define putc_unlocked(c,stream) putc (c, stream)

#  endif

# endif

/* 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 *tty;

  FILE *in, *out;

# if HAVE_TCGETATTR

  struct termios s, t;

# endif

  bool tty_changed = false;

  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.  */

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

  if (tty == NULL)

    {

      in = stdin;

      out = stderr;

    }

  else

    {

      /* We do the locking ourselves.  */

      __fsetlocking (tty, FSETLOCKING_BYCALLER);

      out = in = tty;

    }

  flockfile (out);

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

# if HAVE_TCGETATTR

  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);

    }

# endif

  /* Write the prompt.  */

  fputs_unlocked (prompt, out);

  fflush_unlocked (out);

  /* Read the password.  */

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

  /* According to the C standard, input may not be followed by output

     on the same stream without an intervening call to a file

     positioning function.  Suppose in == out; then without this fseek

     call, on Solaris, HP-UX, AIX, OSF/1, the previous input gets

     echoed, whereas on IRIX, the following newline is not output as

     it should be.  POSIX imposes similar restrictions if fileno (in)

     == fileno (out).  The POSIX restrictions are tricky and change

     from POSIX version to POSIX version, so play it safe and invoke

     fseek even if in != out.  */

  fseeko (out, 0, SEEK_CUR);

  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.  */

              putc_unlocked ('\n', out);

            }

        }

    }

  /* Restore the original setting.  */

# if HAVE_TCSETATTR

  if (tty_changed)

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

# endif

  funlockfile (out);

  call_fclose (tty);

  return buf;

}

#else /* W32 native */

/* Windows implementation by Martin Lambers <marlam@marlam.de>,

   improved by Simon Josefsson. */

/* For PASS_MAX. */

# include <limits.h>

/* For _getch(). */

# include <conio.h>

/* For strdup(). */

# include <string.h>

# ifndef PASS_MAX

#  define PASS_MAX 512

# endif

char *

getpass (const char *prompt)

{

  char getpassbuf[PASS_MAX + 1];

  size_t i = 0;

  int c;

  if (prompt)

    {

      fputs (prompt, stderr);

      fflush (stderr);

    }

  for (;;)

    {

      c = _getch ();

      if (c == '\r')

        {

          getpassbuf[i] = '\0';

          break;

        }

      else if (i < PASS_MAX)

        {

          getpassbuf[i++] = c;

        }

      if (i >= PASS_MAX)

        {

          getpassbuf[i] = '\0';

          break;

        }

    }

  if (prompt)

    {

      fputs ("\r\n", stderr);

      fflush (stderr);

    }

  return strdup (getpassbuf);

}

#endif