libfuse ======= About ----- FUSE (Filesystem in Userspace) is an interface for userspace programs to export a filesystem to the Linux kernel. The FUSE project consists of two components: the *fuse* kernel module (maintained in the regular kernel repositories) and the *libfuse* userspace library (maintained in this repository). libfuse provides the reference implementation for communicating with the FUSE kernel module. A FUSE file system is typically implemented as a standalone application that links with libfuse. libfuse provides functions to mount the file system, unmount it, read requests from the kernel, and send responses back. libfuse offers two APIs: a "high-level", synchronous API, and a "low-level" asynchronous API. In both cases, incoming requests from the kernel are passed to the main program using callbacks. When using the high-level API, the callbacks may work with file names and paths instead of inodes, and processing of a request finishes when the callback function returns. When using the low-level API, the callbacks must work with inodes and responses must be sent explicitly using a separate set of API functions. Installation ------------ You can download libfuse from https://github.com/libfuse/libfuse/releases. After extracting the tarball, build and install with ./configure make -j8 make install You may also need to add `/usr/local/lib` to `/etc/ld.so.conf` and/or run *ldconfig*. If you're building from the git repository (instead of using a release tarball), you also need to run `./makeconf.sh` to create the `configure` script. You'll also need a fuse kernel module (Linux kernels 2.6.14 or later contain FUSE support). For more details see the file `INSTALL` Security implications --------------------- If you run `make install`, the *fusermount* program is installed set-user-id to root. This is done to allow normal users to mount their own filesystem implementations. There must however be some limitations, in order to prevent Bad User from doing nasty things. Currently those limitations are: - The user can only mount on a mountpoint, for which it has write permission - The mountpoint is not a sticky directory which isn't owned by the user (like /tmp usually is) - No other user (including root) can access the contents of the mounted filesystem (though this can be relaxed) Building your own filesystem ------------------------------ FUSE comes with several example file systems in the `examples` directory. For example, the *fusexmp* example mirrors the contents of the root directory under the mountpoint. Start from there and adapt the code! The documentation of the API functions and necessary callbacks is mostly contained in the files `include/fuse.h` (for the high-level API) and `include/fuse_lowlevel.h` (for the low-level API). Getting Help ------------ If you need help, please ask on the mailing list (subscribe at https://lists.sourceforge.net/lists/listinfo/fuse-devel). Please report any bugs on the GitHub issue tracker at https://github.com/libfuse/libfuse/issues.