px4-firmware/nuttx/binfmt/binfmt_unregister.c

/****************************************************************************
 * binfmt/binfmt_unregister.c
 *
 *   Copyright (C) 2009 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 <string.h>
#include <sched.h>
#include <debug.h>
#include <errno.h>

#include <nuttx/binfmt/binfmt.h>

#include "binfmt_internal.h"

#ifndef CONFIG_BINFMT_DISABLE

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

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

/****************************************************************************
 * Name: unregister_binfmt
 *
 * Description:
 *   Register a loader for a binary format
 *
 * Returned Value:
 *   This is a NuttX internal function so it follows the convention that
 *   0 (OK) is returned on success and a negated errno is returned on
 *   failure.
 *
 ****************************************************************************/

int unregister_binfmt(FAR struct binfmt_s *binfmt)
{
  FAR struct binfmt_s *curr;
  FAR struct binfmt_s *prev;
  int ret = -EINVAL;

  if (binfmt)
    {
      /* Disabling pre-emption should be sufficient protection while
       * accessing the list of registered binary format handlers.
       */

      sched_lock();

      /* Search the list of registered binary format handlers for the
       * one to be unregistered.
       */

      for (prev = NULL, curr = g_binfmts;
           curr && curr != binfmt;
           prev = curr, curr = curr->next);

      /* Was it in the list? */

      if (curr)
        {
          /* Yes.. was it at the head of the list? */

          if (!prev)
            {
              /* Yes.. remove it from the head of the list */

              g_binfmts = binfmt->next;
            }
          else
            {
              /* No.. remove it from the middle/end of the list */

              prev->next = binfmt->next;
            }

          binfmt->next = NULL;
          ret = OK;
        }

      sched_unlock();
    }

  return ret;
}

#endif /* CONFIG_BINFMT_DISABLE */