/* Copyright (C) 1991-2018 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 <errno.h>

#include <fcntl.h>

#include <limits.h>

#include <unistd.h>

/* Duplicate FD to FD2, closing the old FD2 and making FD2 be

   open the same file as FD is.  Return FD2 or -1.  */

int

__dup2 (int fd, int fd2)

{

  int save;

  if (fd2 < 0

#ifdef OPEN_MAX

      || fd2 >= OPEN_MAX

#endif

)

    {

      __set_errno (EBADF);

      return -1;

    }

  /* Check if FD is kosher.  */

  if (fcntl (fd, F_GETFL) < 0)

    return -1;

  if (fd == fd2)

    return fd2;

  /* This is not atomic.  */

  save = errno;

  (void) close (fd2);

  __set_errno (save);

  return fcntl (fd, F_DUPFD, fd2);

}

libc_hidden_def (__dup2)

weak_alias (__dup2, dup2)