Implement ISOBUS File Server (FS) Interface as a Personal Project

Introduce the ISOBUS File Server (FS) interface, compatible with ISO
11783-13. The implementation utilizes the kernel's existing CAN J1939
socket support.

For testing following setup can be used:
ip link add type vcan
ip l s dev vcan0 up

j1939acd -r 64-95 -c /tmp/1122334455667788.jacd 1122334455667788 vcan0 &
j1939acd -r 96-127 -c /tmp/1122334455667789.jacd 1122334455667789 vcan0 &

sleep 1

isobusfs-srv -i vcan0 -n 1122334455667788 -v vol1:/path/to/export/
isobusfs-cli -i vcan0 -n 0x1122334455667789 -m 0x1122334455667788 -I

Interactive mode currently support following commands:
exit - exit interactive mode
quit - exit interactive mode
help - show this help
dmesg - show log buffer
selftest - run selftest
ls - list directory
ll - list directory with long listing format
cd - change directory
pwd - print name of current/working directory
get - get file

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>

CMakeLists.txt

@@ -53,6 +53,11 @@ set(PROGRAMS_J1939
     testj1939
 )
 
+set(PROGRAMS_ISOBUSFS
+    isobusfs-srv
+    isobusfs-cli
+)
+
 set(PROGRAMS
     ${PROGRAMS_CANLIB}
     canfdtest
@@ -86,6 +91,7 @@ add_executable(mcp251xfd-dump
 
 if(NOT ANDROID)
   list(APPEND PROGRAMS ${PROGRAMS_J1939})
+  list(APPEND PROGRAMS ${PROGRAMS_ISOBUSFS})
 
   add_library(j1939 STATIC
       libj1939.c