FuseApi

Purpose

The FUSE Api is a C-library (libfuse3) on Linux and similar systems, which support the FUSE kernel feature. This Filesystem in User space option allows to implement the internals of a file system in a process, which runs in user space (not in a kernel module).

This package is designed to support the low level operations in Julia.

Installation

]activate MyFileSystem

]add FuseApi

Usage

Setup functions

There is only one setup function fuse_main_loop(args, module[, user_data]), which delivers commandline arguments of the mount process, the name of the implementing module, which defines the callbacks, and an optional user data object.

Callback functions

For each of the (44) callback functions defined by the library, an implementation may be provided as an exported function of a separate module (named MyFileSystem in this description).

The names and signatures are fixed and can be derived from file fuse-bridge.jl. The callback functions shall return 0 after calling one of the fuse_reply functions, or a error number, as accessible by Base.UV_E.... These error numbers are typically directly passed to the system functions which evoked the callback.

Each callback function requires a call to a specific reply function in the success case. Which one is documented here: In the error case, the framework calls a fuse_reply_err(req, errno) from the returned error code.

The user data object can be accessed with fuser_user_data(req) from the callback functions, which have the req::FuseReq argument and from special arguments in init and destroy.

module MyFileSystem
using FuseApi

# callbacks
export lookup
function lookup(req::FuseReq, parent::FuseIno, name::String)

    return fuse_reply_err(req, errno)

    fuse_reply_stat(req, ...)
end

# setup
main_loop(Base.ARGS, MyFileSystem, user_data)

end # module

Links

The documentation of the C-library is found here: libfuse3-doc.