Added support to access native posix flash via host file system

CODEOWNERS

@@ -309,6 +309,7 @@
 /subsys/debug/                            @nashif
 /subsys/fs/                               @nashif
 /subsys/fs/fcb/                           @nvlsianpu
+/subsys/fs/fuse_fs_access.c               @vanwinkeljan
 /subsys/fs/nvs/                           @Laczen
 /subsys/logging/                          @nordic-krch
 /subsys/net/buf.c                         @jukkar @jhedberg @tbursztyka @pfalcon

boards/posix/native_posix/doc/index.rst

@@ -554,6 +554,9 @@ The following peripherals are currently provided with this board:
   configuration. In case the file does not exists the driver will take care of
   creating the file, else the existing file is used.
 
+  The flash content can be accessed from the host system, as explained in the
+  `Host based flash access`_ section.
+
 UART
 ****
 
@@ -626,3 +629,38 @@ development by integrating more seamlessly with the host operating system:
   A backend/"bottom" for Zephyr's CTF tracing subsystem which writes the tracing
   data to a file in the host filesystem.
   More information can be found in :ref:`Common Tracing Format <ctf>`
+
+Host based flash access
+***********************
+
+If a flash device is present, the file system partitions on the flash
+device can be exposed through the host file system by enabling
+:option:`CONFIG_FUSE_FS_ACCESS`. This option enables a FUSE
+(File system in User space) layer that maps the Zephyr file system calls to
+the required UNIX file system calls, and provides access to the flash file
+system partitions with normal operating system commands such as ``cd``,
+``ls`` and ``mkdir``.
+
+By default the partitions are exposed through the directory *flash* in the
+current working directory. This directory can be changed via the command line
+option *--flash-mount*. As this directory operates as a mount point for FUSE
+you have to ensure that it exists before starting the native POSIX board.
+
+On exit, the native POSIX board application will take care of unmounting the
+directory. In the unfortunate case that the native POSIX board application
+crashes, you can cleanup the stale mount point by using the program
+``fusermount``::
+
+    $ fusermount -u flash
+
+Note that this feature requires a 32-bit version of the FUSE library, with a
+minimal version of 2.6, on the host system and ``pkg-config`` settings to
+correctly pickup the FUSE install path and compiler flags.
+
+On a Ubuntu 18.04 host system, for example, install the ``pkg-config`` and
+``libfuse-dev:i386`` packages, and configure the pkg-config search path with
+these commands::
+
+    $ sudo apt-get install pkg-config libfuse-dev:i386
+    $ export PKG_CONFIG_PATH=/usr/lib/i386-linux-gnu/pkgconfig
+

include/fs.h

@@ -414,6 +414,22 @@ int fs_mount(struct fs_mount_t *mp);
  */
 int fs_unmount(struct fs_mount_t *mp);
 
+/**
+ * @brief Mount point read entry
+ *
+ * Read mount point entry
+ *
+ * @param number Pointer to mount point number
+ * @param name Pointer to mount point name
+ *
+ * @retval 0 Success
+ * @retval -ERRNO errno code if error
+ * @return On success \p number is incremented and \p name is set to mount
+ * point name. In case no mount point exists for the given \p number
+ * -ENOENT is returned and \p name is set to NULL.
+ */
+int fs_readmount(int *number, const char **name);
+
 /**
  * @brief File or directory status
  *

samples/subsys/shell/fs/CMakeLists.txt

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.13.1)
+
+include($ENV{ZEPHYR_BASE}/cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
+project(fs_shell)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

samples/subsys/shell/fs/README.rst

@@ -0,0 +1,152 @@
+.. _shell-fs-sample:
+
+File system shell example
+#########################
+
+Overview
+********
+
+This example provides shell access to a NFFS file system partition in flash.
+
+Requirements
+************
+
+A board with NFFS file system support and UART console
+
+Building
+********
+
+Native Posix
+============
+
+Before starting a build, make sure that the i386 pkconfig directory is in your
+search path.
+
+.. code-block:: console
+
+  export PKG_CONFIG_PATH=/usr/lib/i386-linux-gnu/pkgconfig
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/subsys/shell/fs
+   :board: native_posix
+   :goals: build
+   :compact:
+
+See :ref:`native_posix` on how to connect to the UART.
+
+Reel Board
+==========
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/subsys/shell/fs
+   :board: reel_board
+   :goals: build
+   :compact:
+
+Running
+*******
+
+Once the board has booted, you will be presented with a shell prompt.
+All file system related commands are available as sub-commands of fs.
+
+Begin by mounting the NFSS file system.
+
+.. code-block:: console
+
+  fs mount nffs /nffs
+
+Files System Shell Commands
+===========================
+
+Mount
+-----
+
+Mount a file system partition to a given mount point
+
+.. code-block:: console
+
+  fs mount (nffs|fat) <path>
+
+Ls
+--
+
+List all files and directories in a given path
+
+.. code-block:: console
+
+  fs ls [path]
+
+Cd
+--
+
+Change current working directory to given path
+
+.. code-block:: console
+
+  fs cd [path]
+
+Pwd
+---
+
+List current working directory
+
+.. code-block:: console
+
+  fs pwd
+
+Write
+-----
+
+Write hexadecimal numbers to a given file.
+Optionally a offset in the file can be given.
+
+.. code-block:: console
+
+  fs write <path> [-o <offset>] <hex number> ...
+
+Read
+----
+
+Read file and dump in hex and ASCII format
+
+.. code-block:: console
+
+  fs read <path>
+
+Trunc
+-----
+
+Truncate a given file
+
+.. code-block:: console
+
+  fs trunc <path>
+
+Mkdir
+-----
+
+Create a directory
+
+.. code-block:: console
+
+  fs mkdir <path>
+
+Rm
+--
+
+Remove a file or directory
+
+.. code-block:: console
+
+  fs rm <path>
+
+Flash Host Access
+=================
+
+For the Native POSIX board the flash partitions can be accessed from the host
+Linux system.
+
+By default the flash partitions are accessible through the directory *flash*
+relative to the directory where the build is started.
+
+

samples/subsys/shell/fs/boards/native_posix.conf

@@ -0,0 +1,2 @@
+CONFIG_FUSE_FS_ACCESS=y
+

samples/subsys/shell/fs/boards/reel_board.conf

@@ -0,0 +1,2 @@
+CONFIG_MPU_ALLOW_FLASH_WRITE=y
+

samples/subsys/shell/fs/prj.conf

@@ -0,0 +1,17 @@
+CONFIG_FLASH=y
+
+CONFIG_LOG=y
+
+CONFIG_HEAP_MEM_POOL_SIZE=16384
+
+CONFIG_SHELL=y
+
+CONFIG_FLASH=y
+
+CONFIG_FILE_SYSTEM=y
+CONFIG_FILE_SYSTEM_NFFS=y
+CONFIG_FILE_SYSTEM_SHELL=y
+CONFIG_FS_NFFS_FLASH_DEV_NAME="flash_ctrl"
+
+CONFIG_LOG=y
+

samples/subsys/shell/fs/sample.yaml

@@ -0,0 +1,6 @@
+sample:
+  description: FS shell sample
+  name: FS shell
+tests:
+  test_fs_shell:
+    platform_whitelist: reel_board

samples/subsys/shell/fs/src/main.c

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2019 Jan Van Winkel <jan.van_winkel@dxplore.eu>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+
+#define LOG_LEVEL CONFIG_LOG_DEFAULT_LEVEL
+#include <logging/log.h>
+LOG_MODULE_REGISTER(app);
+
+void main(void)
+{
+}

samples/subsys/shell/shell.rst

@@ -0,0 +1,10 @@
+.. _shell-samples:
+
+Shell System Samples
+####################
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

subsys/fs/CMakeLists.txt

@@ -19,3 +19,13 @@ endif()
 
 add_subdirectory_ifdef(CONFIG_FCB  ./fcb)
 add_subdirectory_ifdef(CONFIG_NVS  ./nvs)
+
+if(CONFIG_FUSE_FS_ACCESS)
+  zephyr_library_named(FS_FUSE)
+  find_package(PkgConfig REQUIRED)
+  pkg_search_module(FUSE REQUIRED fuse)
+  zephyr_include_directories(${FUSE_INCLUDE_DIR})
+  zephyr_link_libraries(${FUSE_LIBRARIES})
+  zephyr_library_compile_definitions(_FILE_OFFSET_BITS=64)
+  zephyr_library_sources(fuse_fs_access.c)
+endif()

subsys/fs/Kconfig

@@ -51,6 +51,12 @@ config FILE_SYSTEM_SHELL
 	  This shell provides basic browsing of the contents of the
 	  file system.
 
+config FUSE_FS_ACCESS
+	bool "Enable FUSE based access to file system partitions"
+	depends on ARCH_POSIX
+	help
+	  Expose file system partitions to the host system through FUSE.
+
 menu "FatFs Settings"
 	visible if FAT_FILESYSTEM_ELM
 

subsys/fs/fs.c

@@ -515,6 +515,38 @@ int fs_unmount(struct fs_mount_t *mp)
 	return rc;
 }
 
+int fs_readmount(int *number, const char **name)
+{
+	sys_dnode_t *node;
+	int rc = -ENOENT;
+	int cnt = 0;
+	struct fs_mount_t *itr = NULL;
+
+	*name = NULL;
+
+	k_mutex_lock(&mutex, K_FOREVER);
+
+	SYS_DLIST_FOR_EACH_NODE(&fs_mnt_list, node) {
+		if (*number == cnt) {
+			itr = CONTAINER_OF(node, struct fs_mount_t, node);
+			break;
+		}
+
+		++cnt;
+	}
+
+	k_mutex_unlock(&mutex);
+
+	if (itr != NULL) {
+		rc = 0;
+		*name = itr->mnt_point;
+		++(*number);
+	}
+
+	return rc;
+
+}
+
 /* Register File system */
 int fs_register(enum fs_type type, struct fs_file_system_t *fs)
 {