nuttx/net/socket/net_checksd.c

/****************************************************************************
 * net/socket/net_checksd.c
 *
 *   Copyright (C) 2011 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 <sys/socket.h>

#include <sched.h>
#include <errno.h>
#include <debug.h>

#include "socket/socket.h"

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

/****************************************************************************
 * Name: net_checksd
 *
 * Description:
 *   Check if the socket descriptor is valid for the provided TCB and if it
 *   supports the requested access.  This trivial operation is part of the
 *   fdopen() operation when the fdopen() is performed on a socket descriptor.
 *   It simply performs some sanity checking before permitting the socket
 *   descriptor to be wrapped as a C FILE stream.
 *
 ****************************************************************************/

#if defined(CONFIG_NET) && CONFIG_NFILE_DESCRIPTORS > 0
int net_checksd(int sd, int oflags)
{
  FAR struct socket *psock = sockfd_socket(sd);

  /* Verify that the sockfd corresponds to valid, allocated socket */

  if (!psock || psock->s_crefs <= 0)
    {
      nvdbg("No valid socket for sd: %d\n", sd);
      return -EBADF;
    }

  /* NOTE:  We permit the socket FD to be "wrapped" in a stream as
   * soon as the socket descriptor is created by socket().  Therefore
   * (1) we don't care if the socket is connected yet, and (2) there
   * are no access restrictions that can be enforced yet.
   */

  return OK;
}
#endif /* CONIG_NET && CONFIG_NFILE_DESCRIPTORS > 0 */