/****************************************************************************
 * fs/vfs/fs_dup.c
 *
 *   Copyright (C) 2007-2009, 2017 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include "vfs_config.h"

#include "errno.h"
#include "unistd.h"
#include "sched.h"

#include "vnode.h"
#if defined(LOSCFG_NET_LWIP_SACK)
#include "lwip/sockets.h"
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: dup
 *
 * Description:
 *   Clone a file or socket descriptor to an arbitray descriptor number
 *
 ****************************************************************************/

int dup(int fd)
{
  int ret = OK;

  /* Check the range of the descriptor to see if we got a file or a socket
   * descriptor.
   */

#if CONFIG_NFILE_DESCRIPTORS > 0
  if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS)
    {
      /* 0,1,2 fd is not opened in system, no need to dup them, return fd directly */

      if ((fd >= STDIN_FILENO) && (fd <= STDERR_FILENO))
        {
          return fd;
        }

      /* Its a valid file descriptor.. dup the file descriptor using any
       * other file descriptor.  fd_dupfd() sets the errno value in the
       * event of any failures.
       */

      ret = fs_dupfd(fd, 3); /* 3: file start fd */
    }
  else
#endif
    {
      /* Not a valid file descriptor.  Did we get a valid socket descriptor? */
#if defined(LOSCFG_NET_LWIP_SACK)
      if ((unsigned int)fd < (unsigned int)(CONFIG_NFILE_DESCRIPTORS+CONFIG_NSOCKET_DESCRIPTORS))
        {
          /* Yes.. dup the socket descriptor.  The errno value is not set. */

          set_errno(EBADF); /* When net_dupsd is still closed,errno should set */
          ret = VFS_ERROR;

        }
      else
#endif
        {
          /* No.. then it is a bad descriptor number */

          set_errno(EBADF);
          ret = VFS_ERROR;
        }
    }

  return ret;
}