text: /****************************************************************************
   * sched/module/mod_rmmod.c
   *
   *   Copyright (C) 2015, 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 <nuttx/config.h>
  
  #include <sys/types.h>
  #include <assert.h>
  #include <errno.h>
  
  #include <nuttx/kmalloc.h>
  #include <nuttx/module.h>
  #include <nuttx/lib/modlib.h>
  
  #ifdef CONFIG_MODULE
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: rmmod
   *
   * Description:
   *   Remove a previously installed module from memory.
   *
   * Input Parameters:
   *   handle - The module handler previously returned by insmod().
   *
   * Returned Value:
   *   Zero (OK) on success.  On any failure, -1 (ERROR) is returned the
   *   errno value is set appropriately.
   *
   ****************************************************************************/
  
  int rmmod(FAR void *handle)
  {
    FAR struct module_s *modp = (FAR struct module_s *)handle;
    int ret;
  
    DEBUGASSERT(modp != NULL);
  
    /* Get exclusive access to the module registry */
  
    modlib_registry_lock();
  
    /* Verify that the module is in the registry */
  
    ret = modlib_registry_verify(modp);
    if (ret < 0)
      {
        berr("ERROR: Failed to verify module: %d\n", ret);
        goto errout_with_lock;
      }
  
  #if CONFIG_MODLIB_MAXDEPEND > 0
    /* Refuse to remove any module that other modules may depend upon. */
  
    if (modp->dependents > 0)
      {
        berr("ERROR: Module has dependents: %d\n", modp->dependents);
        ret = -EBUSY;
        goto errout_with_lock;
      }
  #endif
  
    /* Is there an uninitializer? */
  
    if (modp->modinfo.uninitializer != NULL)
      {
        /* Try to uninitialize the module */
  
        ret = modp->modinfo.uninitializer(modp->modinfo.arg);
  
        /* Did the module successfully uninitialize? */
  
        if (ret < 0)
          {
            berr("ERROR: Failed to uninitialize the module: %d\n", ret);
            goto errout_with_lock;
          }
  
        /* Nullify so that the uninitializer cannot be called again */
  
        modp->modinfo.uninitializer = NULL;
  #if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MODULE)
        modp->initializer           = NULL;
        modp->modinfo.arg           = NULL;
        modp->modinfo.exports       = NULL;
        modp->modinfo.nexports      = 0;
  #endif
      }
  
    /* Release resources held by the module */
  
    if (modp->alloc != NULL)
      {
        /* Free the module memory */
  
        kmm_free((FAR void *)modp->alloc);
  
        /* Nullify so that the memory cannot be freed again */
  
        modp->alloc = NULL;
  #if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MODULE)
        modp->textsize  = 0;
        modp->datasize  = 0;
  #endif
      }
  
    /* Remove the module from the registry */
  
    ret = modlib_registry_del(modp);
    if (ret < 0)
      {
        berr("ERROR: Failed to remove the module from the registry: %d\n",
             ret);
        goto errout_with_lock;
      }
  
  #if CONFIG_MODLIB_MAXDEPEND > 0
    /* Eliminate any dependencies that this module has on other modules */
  
    modlib_undepend(modp);
  #endif
    modlib_registry_unlock();
  
    /* And free the registry entry */
  
    kmm_free(modp);
    return OK;
  
  errout_with_lock:
    modlib_registry_unlock();
    set_errno(-ret);
    return ERROR;
  }
  
  #endif /* CONFIG_MODULE */
  