/* Copyright (C) 1998-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.

   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 <errno.h>

#include <fcntl.h>

#include <string.h>

#include <unistd.h>

/* Prefix for master pseudo terminal nodes.  */

#define _PATH_PTY "/dev/pty"

/* Letters indicating a series of pseudo terminals.  */

#ifndef PTYNAME1

#define PTYNAME1 "pqrsPQRS"

#endif

const char __libc_ptyname1[] attribute_hidden = PTYNAME1;

/* Letters indicating the position within a series.  */

#ifndef PTYNAME2

#define PTYNAME2 "0123456789abcdefghijklmnopqrstuv";

#endif

const char __libc_ptyname2[] attribute_hidden = PTYNAME2;

/* Open a master pseudo terminal and return its file descriptor.  */

int

__getpt (void)

{

  char buf[sizeof (_PATH_PTY) + 2];

  const char *p, *q;

  char *s;

  s = __mempcpy (buf, _PATH_PTY, sizeof (_PATH_PTY) - 1);

  /* s[0] and s[1] will be filled in the loop.  */

  s[2] = '\0';

  for (p = __libc_ptyname1; *p != '\0'; ++p)

    {

      s[0] = *p;

      for (q = __libc_ptyname2; *q != '\0'; ++q)

	{

	  int fd;

	  s[1] = *q;

	  fd = __open (buf, O_RDWR);

	  if (fd != -1)

	    return fd;

	  if (errno == ENOENT)

	    return -1;

	}

    }

  __set_errno (ENOENT);

  return -1;

}

#undef __getpt

weak_alias (__getpt, getpt)

#ifndef HAVE_POSIX_OPENPT

/* We cannot define posix_openpt in general for BSD systems.  */

int

__posix_openpt (int oflag)

{

  __set_errno (ENOSYS);

  return -1;

}

weak_alias (__posix_openpt, posix_openpt)

stub_warning (posix_openpt)

#endif