Add an implementation of rmmod

ChangeLog

@@ -11237,4 +11237,5 @@
 	  just the ELF module support with name changes (2015-12-10).
 	* configs/samv71-xult/module:  Add configuration for testing OS
 	  modules (2015-12-12).
+	* sched/module:  Add an implementation of rmmod() (2015-11-12).
 

include/nuttx/module.h

@@ -76,25 +76,43 @@
  * Public Types
  ****************************************************************************/
 
+/* This is the type of the function that is called to uninitialize the
+ * the loaded module.  This may mean, for example, un-registering a device
+ * driver. If the module is successfully initialized, its memory will be
+ * deallocated.
+ *
+ * Input Parameters:
+ *   arg - An opaque argument that was previously returned by the initializer
+ *         function.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on any failure to
+ *   initialize the module.  If zero is returned, then the module memory
+ *   will be deallocated.  If the module is still in use (for example with
+ *   open driver instances), the uninitialization function should fail with
+ *   -EBUSY
+ */
+
+typedef CODE int (*mod_uninitializer_t)(FAR void *arg);
+
 /* A NuttX module is expected to export a function called module_initialize()
  * that has the following function prototype.  This function should appear as
  * the entry point in the ELF module file and will be called bythe binfmt
  * logic after the module has been loaded into kernel memory.
  *
- * As an alternative using GCC, the module may mark a function with the
- * "constructor" attribute and the module initializer will be called along
- * with any other C++ constructors.  The "destructor" attribute may also
- * be used to mark an module uninitialization function.
- *
  * Input Parameters:
- *   None
+ *   uninitializer - The pointer to the uninitialization function.  NULL may
+ *     be returned if no uninitialization is needed (i.e, the the module
+ *     memory can be deallocated at any time).
+ *   arg - An argument that will be passed to the uninitialization function.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on any failure to
  *   initialize the module.
  */
 
-typedef CODE int (*mod_initializer_t)(void);
+typedef CODE int (*mod_initializer_t)(mod_uninitializer_t *uninitializer,
+                                      FAR void **arg);
 
 /* This describes the file to be loaded. */
 
@@ -111,7 +129,8 @@ struct module_s
    * resources used by the loaded module.
    */
 
-  mod_initializer_t initializer;       /* Module initializer function */
+  mod_uninitializer_t uninitializer;   /* Module initializer function */
+  FAR void *arg;                       /* Uninitializer argument */
   FAR void *alloc;                     /* Allocated kernel memory */
 };
 
@@ -139,6 +158,16 @@ extern "C"
 
 int insmod(FAR struct module_s *modp);
 
+/****************************************************************************
+ * Name: rmmod
+ *
+ * Description:
+ *   Remove a previously installed module from memory.
+ *
+ ****************************************************************************/
+
+int rmmod(FAR struct module_s *modp);
+
 #undef EXTERN
 #if defined(__cplusplus)
 }

sched/module/Make.defs

@@ -37,7 +37,7 @@ ifeq ($(CONFIG_MODULE),y)
 
 # OS module interfaces
 
-CSRCS += mod_insmod.c
+CSRCS += mod_insmod.c mod_rmmod.c
 
 # loadable module library
 

sched/module/mod_insmod.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * sched/module/module.c
+ * sched/module/mod_insmod.c
  *
  *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
@@ -46,8 +46,6 @@
 #include <debug.h>
 #include <errno.h>
 
-#include <arpa/inet.h>
-
 #include <nuttx/arch.h>
 #include <nuttx/module.h>
 
@@ -172,8 +170,10 @@ static void mod_dumpinitializer(mod_initializer_t initializer,
 int insmod(FAR struct module_s *modp)
 {
   struct mod_loadinfo_s loadinfo;
+  mod_initializer_t initializer;
   int ret;
 
+  DEBUGASSERT(modp != NULL && modp->filename != NULL);
   bvdbg("Loading file: %s\n", modp->filename);
 
   /* Initialize the ELF library to load the program binary. */
@@ -207,23 +207,20 @@ int insmod(FAR struct module_s *modp)
 
   /* Return the load information */
 
-  modp->initializer = (mod_initializer_t)(loadinfo.textalloc + loadinfo.ehdr.e_entry);
   modp->alloc       = (FAR void *)loadinfo.textalloc;
 
   /* Get the module initializer entry point */
 
-  if (modp->initializer)
+  initializer = (mod_initializer_t)(loadinfo.textalloc + loadinfo.ehdr.e_entry);
+  mod_dumpinitializer(initializer, &loadinfo);
+
+  /* Call the module initializer */
+
+  ret = initializer(&modp->uninitializer, &modp->arg);
+  if (ret < 0)
     {
-      mod_dumpinitializer(modp->initializer, &loadinfo);
+      bdbg("Failed to initialize the module: %d\n", ret);
-
+      goto errout_with_load;
-      /* Call the module initializer */
-
-      ret = modp->initializer();
-      if (ret < 0)
-        {
-          bdbg("Failed to initialize the module: %d\n", ret);
-          goto errout_with_load;
-        }
     }
 
   mod_uninitialize(&loadinfo);

sched/module/mod_rmmod.c

@@ -0,0 +1,100 @@
+/****************************************************************************
+ * sched/module/module.c
+ *
+ *   Copyright (C) 2015 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 <stdint.h>
+#include <string.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/module.h>
+
+#include "module/module.h"
+
+#ifdef CONFIG_MODULE
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rmmod
+ *
+ * Description:
+ *   Remove a previously installed module from memory.
+ *
+ ****************************************************************************/
+
+int rmmod(FAR struct module_s *modp)
+{
+  int ret = OK;
+
+  DEBUGASSERT(modp != NULL);
+
+  /* Is there an uninitializer? */
+
+  if (modp->uninitializer != NULL)
+    {
+      /* Try to uninitializer the module */
+
+      ret = modp->uninitializer(modp->arg);
+
+      /* Did the module sucessfully uninitialize? */
+
+      if (ret < 0)
+        {
+          sdbg("ERROR: Failed to uninitialize the module: %d\n", ret);
+          return ret;
+        }
+    }
+
+  /* Free the module memory */
+
+  /* Release memory holding the relocated ELF image */
+
+  if (modp->alloc != 0)
+    {
+      kmm_free((FAR void *)modp->alloc);
+    }
+
+  return ret;
+}
+
+#endif /* CONFIG_MODULE */