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/* Copyright (C) 1998 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#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 = PTYNAME1;

/* Letters indicating the position within a series.  */
#ifndef PTYNAME2
#define PTYNAME2 "0123456789abcdefghijklmnopqrstuv";
#endif
const char *__libc_ptyname2 = 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 = __stpcpy (buf, _PATH_PTY);
  s[0] = '?';
  s[1] = '?';
  s[2] = 0;

  for (p = __libc_ptyname1; *p; p++)
    {
      s[0] = *p;

      for (q = __libc_ptyname2; *q; q++)
	{
	  int fd;
	  
	  s[1] = *q;
	  
	  fd = __open (buf, O_RDWR);
	  if (fd != -1)
	    {
	      if (__isatty (fd))
		return fd;
	      
	      __close (fd);
	      continue;
	    }
	  
	  if (errno != EIO)
	    return -1;
	}
    }

  __set_errno (ENFILE);
  return -1;
}
weak_alias (__getpt, getpt)