text: /****************************************************************************
   * net/socket/net_dup2.c
   *
   *   Copyright (C) 2009, 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"
  
  #if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
  
  /****************************************************************************
   * Global Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Function: net_dup2
   *
   * Description:
   *   Clone a socket descriptor to an arbitray descriptor number.  If file
   *   descriptors are implemented, then this is called by dup2() for the case
   *   of socket file descriptors.  If file descriptors are not implemented,
   *   then this function IS dup2().
   *
   ****************************************************************************/
  
  #if CONFIG_NFILE_DESCRIPTORS > 0
  int net_dup2(int sockfd1, int sockfd2)
  #else
  int dup2(int sockfd1, int sockfd2)
  #endif
  {
    FAR struct socket *psock1;
    FAR struct socket *psock2;
    int err;
    int ret;
  
    /* Lock the scheduler throughout the following */
  
    sched_lock();
  
    /* Get the socket structures underly both descriptors */
  
    psock1 = sockfd_socket(sockfd1);
    psock2 = sockfd_socket(sockfd2);
  
    /* Verify that the sockfd1 and sockfd2 both refer to valid socket
     * descriptors and that sockfd2 corresponds to allocated socket
     */
  
    if (!psock1 || !psock2 || psock1->s_crefs <= 0)
      {
        err = EBADF;
        goto errout;
      }
  
    /* If sockfd2 also valid, allocated socket, then we will have to
     * close it!
     */
  
    if (psock2->s_crefs > 0)
      {
        net_close(sockfd2);
      }
  
    /* Duplicate the socket state */
  
    ret = net_clone(psock1, psock2);
    if (ret < 0)
      {
        err = -ret;
        goto errout;
      }
  
    sched_unlock();
    return OK;
  
  errout:
    sched_unlock();
    errno = err;
    return ERROR;
  }
  
  #endif /* CONFIG_NET && CONFIG_NSOCKET_DESCRIPTORS > 0 */
  
  
  