text: /****************************************************************************
   * fs/vfs/fs_close.c
   *
   *   Copyright (C) 2007-2009, 2012 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 <nuttx/config.h>
  
  #include <unistd.h>
  #include <sched.h>
  #include <errno.h>
  #include <nuttx/fs/fs.h>
  
  #if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
  # include <nuttx/net/net.h>
  #endif
  
  #include "inode/inode.h"
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: close
   *
   * Description:
   *   close() closes a file descriptor, so that it no longer refers to any
   *   file and may be reused. Any record locks (see fcntl(2)) held on the file
   *   it was associated with, and owned by the process, are removed (regardless
   *   of the file descriptor that was used to obtain the lock).
   *
   *   If fd is the last copy of a particular file descriptor the resources
   *   associated with it are freed; if the descriptor was the last reference
   *   to a file which has been removed using unlink(2) the file is deleted.
   *
   * Parameters:
   *   fd   file descriptor to close
   *
   * Returned Value:
   *   0 on success; -1 on error with errno set appropriately.
   *
   * Assumptions:
   *
   ****************************************************************************/
  
  int close(int fd)
  {
    int err;
  #if CONFIG_NFILE_DESCRIPTORS > 0
    int ret;
  
    /* Did we get a valid file descriptor? */
  
    if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
  #endif
      {
        /* Close a socket descriptor */
  
  #if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
        if ((unsigned int)fd < (CONFIG_NFILE_DESCRIPTORS+CONFIG_NSOCKET_DESCRIPTORS))
          {
            return net_close(fd);
          }
        else
  #endif
          {
            err = EBADF;
            goto errout;
          }
      }
  
  #if CONFIG_NFILE_DESCRIPTORS > 0
    /* Close the driver or mountpoint.  NOTES: (1) there is no
     * exclusion mechanism here , the driver or mountpoint must be
     * able to handle concurrent operations internally, (2) The driver
     * may have been opened numerous times (for different file
     * descriptors) and must also handle being closed numerous times.
     * (3) for the case of the mountpoint, we depend on the close
     * methods bing identical in signature and position in the operations
     * vtable.
     */
  
    ret = files_close(fd);
    if (ret < 0)
      {
        /* An error occurred while closing the driver */
  
        err = -ret;
        goto errout;
      }
    return OK;
  
  #endif
  
  errout:
    set_errno(err);
    return ERROR;
  }
  
  