fs/driver: Add a generic function to find a driver pointer by filesystem path

Add a function to find any driver's registered pointer by the filesystem path.

Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>

fs/driver/CMakeLists.txt

@@ -31,6 +31,7 @@ if(NOT CONFIG_DISABLE_MOUNTPOINT)
     SRCS
     fs_registerblockdriver.c
     fs_unregisterblockdriver.c
+    fs_finddriver.c
     fs_findblockdriver.c
     fs_openblockdriver.c
     fs_closeblockdriver.c

fs/driver/Make.defs

@@ -29,8 +29,7 @@ ifneq ($(CONFIG_DISABLE_MOUNTPOINT),y)
 CSRCS += fs_registerblockdriver.c fs_unregisterblockdriver.c
 CSRCS += fs_findblockdriver.c fs_openblockdriver.c fs_closeblockdriver.c
 CSRCS += fs_blockpartition.c fs_findmtddriver.c fs_closemtddriver.c
-CSRCS += fs_blockmerge.c
-
+CSRCS += fs_blockmerge.c fs_finddriver.c
 
 ifeq ($(CONFIG_MTD),y)
 CSRCS += fs_registermtddriver.c fs_unregistermtddriver.c

fs/driver/fs_finddriver.c

@@ -0,0 +1,78 @@
+/****************************************************************************
+ * fs/driver/fs_finddriver.c
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <debug.h>
+
+#include "inode/inode.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: find_driver
+ *
+ * Description:
+ *   Returns the pointer of a registered driver specified by 'pathname'
+ *
+ * Input Parameters:
+ *   pathname - the full path to the driver's device node in file system
+ *
+ * Returned Value:
+ *   Pointer to driver's registered private pointer or NULL if not found.
+ *
+ ****************************************************************************/
+
+FAR void *find_driver(FAR const char *pathname)
+{
+  struct inode_search_s desc;
+  FAR void *drvr = NULL;
+
+  DEBUGASSERT(pathname != NULL);
+
+  /* Find the inode registered with this pathname */
+
+  SETUP_SEARCH(&desc, pathname, false);
+
+  /* Get the search results */
+
+  inode_lock();
+  if (inode_find(&desc) < 0)
+    {
+      ferr("ERROR: Failed to find %s\n", pathname);
+    }
+  else
+    {
+      drvr = desc.node->i_private;
+      inode_release(desc.node);
+    }
+
+  inode_unlock();
+  RELEASE_SEARCH(&desc);
+
+  return drvr;
+}

include/nuttx/fs/fs.h

@@ -1369,6 +1369,22 @@ int fdlist_close(FAR struct fdlist *list, int fd);
 
 int nx_close(int fd);
 
+/****************************************************************************
+ * Name: find_driver
+ *
+ * Description:
+ *   Returns the pointer of a registered driver specified by 'pathname'
+ *
+ * Input Parameters:
+ *   pathname - the full path to the driver's device node in file system
+ *
+ * Returned Value:
+ *   Pointer to driver's registered private pointer or NULL if not found.
+ *
+ ****************************************************************************/
+
+FAR void *find_driver(FAR const char *pathname);
+
 /****************************************************************************
  * Name: open_blockdriver
  *