From ab568fd909943c43fb469b2c81f4447ea2141430 Mon Sep 17 00:00:00 2001
From: Giovanni Di Sirio <gdisirio@gmail.com>
Date: Mon, 29 Nov 2021 13:54:15 +0000
Subject: [PATCH] git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@15153
 27425a3e-05d8-49a3-a47f-9c15f0e5edd8

---
 demos/STM32/RT-VFS-FATFS/main.c     |  5 ++--
 os/vfs/drivers/overlay/drvoverlay.c | 42 ++++++++++++++++++++---------
 os/vfs/drivers/overlay/drvoverlay.h |  3 +++
 3 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/demos/STM32/RT-VFS-FATFS/main.c b/demos/STM32/RT-VFS-FATFS/main.c
index c7cfe28c5..4fd94b28e 100644
--- a/demos/STM32/RT-VFS-FATFS/main.c
+++ b/demos/STM32/RT-VFS-FATFS/main.c
@@ -229,8 +229,9 @@ int main(void) {
   sdStart(&PORTAB_SD1, NULL);
   nullObjectInit(&nullstream);
 
-  /* Initializing an overlay VFS object as a root, no need for a name.*/
-  drvOverlayObjectInit(&vfs_root, "");
+  /* Initializing an overlay VFS object as a root, bo overlaid driver,
+     no need for a name.*/
+  drvOverlayObjectInit(&vfs_root, NULL, "");
 
   /* Registering a streams VFS driver on the VFS overlay root as "/dev".*/
   msg = drvOverlayRegisterDriver(&vfs_root,
diff --git a/os/vfs/drivers/overlay/drvoverlay.c b/os/vfs/drivers/overlay/drvoverlay.c
index 0ffc95977..56da21a14 100644
--- a/os/vfs/drivers/overlay/drvoverlay.c
+++ b/os/vfs/drivers/overlay/drvoverlay.c
@@ -104,13 +104,14 @@ static msg_t drv_open_dir(void *instance,
                           const char *path,
                           vfs_directory_node_t **vdnpp) {
   vfs_overlay_driver_t *drvp = (vfs_overlay_driver_t *)instance;
+  const char *scanpath = path;
   msg_t err;
 
   do {
-    err = vfs_parse_match_separator(&path);
+    err = vfs_parse_match_separator(&scanpath);
     VFS_BREAK_ON_ERROR(err);
 
-    if (*path == '\0') {
+    if (*scanpath == '\0') {
 
       /* Creating a root directory node.*/
       vfs_overlay_dir_node_t *onp = chPoolAlloc(&drvp->dir_nodes_pool);
@@ -129,11 +130,23 @@ static msg_t drv_open_dir(void *instance,
     else {
       vfs_driver_t *dp;
 
-      /* Delegating node creation to a registered driver.*/
-      err = match_driver(drvp, &path, &dp);
-      VFS_BREAK_ON_ERROR(err);
-
-      err = dp->vmt->open_dir((void *)dp, path, vdnpp);
+      /* Searching for a match among registered overlays.*/
+      err = match_driver(drvp, &scanpath, &dp);
+      if (err == VFS_RET_SUCCESS) {
+        /* Delegating node creation to a registered driver.*/
+        err = dp->vmt->open_dir((void *)dp,
+                                scanpath,
+                                vdnpp);
+      }
+      else {
+        /* No matching overlay, the whole path is passed to the overlaid
+           driver, if defined, else returning the previous error.*/
+        if (drvp->overlaid_drv != NULL) {
+          err = drvp->overlaid_drv->vmt->open_dir((void *)drvp->overlaid_drv,
+                                                  path,
+                                                  vdnpp);
+        }
+      }
     }
   }
   while (false);
@@ -215,18 +228,21 @@ static msg_t node_dir_next(void *instance, vfs_node_info_t *nip) {
 /**
  * @brief   VFS overlay object initialization.
  *
- * @param[out] vodp     pointer to a @p vfs_overlay_driver_t structure
- * @param[in] rootname  name to be attributed to this object
- * @return              A pointer to this initialized object.
+ * @param[out] vodp             pointer to a @p vfs_overlay_driver_t structure
+ * @param[out] overlaid_drv     pointer to a driver to be overlaid
+ * @param[in] rootname          name to be attributed to this object
+ * @return                      A pointer to this initialized object.
  *
  * @api
  */
 vfs_driver_t *drvOverlayObjectInit(vfs_overlay_driver_t *vodp,
+                                   vfs_driver_t *overlaid_drv,
                                    const char *rootname) {
 
-  vodp->vmt         = &driver_vmt;
-  vodp->rootname    = rootname;
-  vodp->next_driver = &vodp->drivers[0];
+  vodp->vmt          = &driver_vmt;
+  vodp->rootname     = rootname;
+  vodp->overlaid_drv = overlaid_drv;
+  vodp->next_driver  = &vodp->drivers[0];
 
   /* Initializing pools.*/
   chPoolObjectInit(&vodp->dir_nodes_pool,
diff --git a/os/vfs/drivers/overlay/drvoverlay.h b/os/vfs/drivers/overlay/drvoverlay.h
index 9d4caa65c..a129df8b5 100644
--- a/os/vfs/drivers/overlay/drvoverlay.h
+++ b/os/vfs/drivers/overlay/drvoverlay.h
@@ -105,6 +105,8 @@ typedef struct vfs_overlay_dir_node {
   __vfs_driver_data                                                         \
   /* Pool of directory nodes.*/                                             \
   memory_pool_t                     dir_nodes_pool;                         \
+  /* Driver to be overlaid or NULL.*/                                       \
+  vfs_driver_t                      *overlaid_drv;                          \
   /* Static storage of directory nodes.*/                                   \
   vfs_overlay_dir_node_t            dir_nodes[DRV_CFG_OVERLAY_DIR_NODES_NUM]; \
   /* Next registration slot.*/                                              \
@@ -142,6 +144,7 @@ typedef struct vfs_drv_overlay {
 extern "C" {
 #endif
   vfs_driver_t *drvOverlayObjectInit(vfs_overlay_driver_t *vodp,
+                                     vfs_driver_t *overlaid_drv,
                                      const char *rootname);
   msg_t drvOverlayRegisterDriver(vfs_overlay_driver_t *vodp,
                                  vfs_driver_t *vdp);