write filesystems in Perl using FUSE
XS Perl6 Perl


Fuse Perl bindings

This module lets you implement filesystems in Perl, through the FUSE (Filesystem in USErspace) kernel/lib interface.

  use Fuse;

      mountpoint => '/mnt/my_fs',
      threaded   => 0,
      debug      => 1,

      getattr    => sub { ... }, # fetches attributes, like 'stat'
      getdir     => sub { ... }, # obtains directory listings
      open       => sub { ... }, # opens files
      statfs     => sub { ... }, # returns filesystem data
      read       => sub { ... }, # reads file contents

      # there are many more you can implement!

See Fuse's main documentation for more details.


This module requires the FUSE C library and the FUSE kernel module, both available at http://fuse.sourceforge.net. It should work with versions 2.6 and up.

There are pre-built packages for FUSE in major operating systems:

Debian: sudo apt-get install libfuse-dev

RedHat: sudo yum install fuse-devel

OSX: install OSXFUSE manually or via homebrew brew install osxfuse

Solaris: enable the 'sfe' repository, then install libfuse

FUSE is also available on the main BSD flavours, but please see the notes below for extra information:

FreeBSD: install fusefs-libs from ports

NetBSD: install librefuse or perfuse from pkgsrc

OpenBSD: (see below)

If you intend to use FUSE in threaded mode, you need a version of perl compiled with USE_ITHREADS. Then, you need to use threads and threads::shared.

After installing the external libraries, you can install the Fuse module using you favorite CPAN tool. For example:

cpanm Fuse

Or manually, by downloading, unpacking and typing:

perl Makefile.PL
make test
make install


We have bundled a few example scripts in the examples/ subdirectory. These are:

  • example.pl, a simple "Hello world" type of script

  • loopback.pl, a filesystem loopback-device. Like fusexmp from the main FUSE dist, it simply recurses file operations into the real filesystem. However, unlike fusexmp, it only re-shares files under the /tmp/test directory.

  • rmount.pl, an NFS-workalike which tunnels through SSH. It requires an account on some ssh server (obviously) with public-key authentication enabled (if you have to type in a password, you don't have this. See man ssh_keygen for more information). Copy rmount_remote.pl to your home directory on the remote machine, and create a subdir somewhere, and then run it like: ./rmount.pl host /remote/dir /local/dir

  • rmount_remote.pl, a ripoff of loopback.pl meant to be used as a backend for rmount.pl.

Happy FUSEing!

Notes for BSD users

On NetBSD, there is a potential issue with readdir() only being called once when using librefuse. However, currently using Perfuse causes other issues (readlink() drops the last character from the read link path, and the block count in stat() is incorrect). We will be addressing these concerns with the appropriate developers in the near future.

If you are using Perfuse on NetBSD, you should do the following (as root):

cat >> /etc/sysctl.conf <<_EOT_
sysctl -f /etc/sysctl.conf

Perfuse uses TCP sockets, and needs large send buffers.

On NetBSD and FreeBSD, extended attributes do not work. These are specifically related to the FUSE implementations on those platforms.

Normally you can not mount FUSE filesystems as non-root users on FreeBSD and NetBSD. They can allow non-root users to mount FUSE filesystems, but instead of changing the mode of /dev/fuse or /bin/fusermount, you need to use sysctl to allow user mounts. For FreeBSD, this involves (as root):

sysctl -w vfs.usermount=1
pw usermod <your username here> -G operator

And on NetBSD (also as root):

sysctl -w vfs.generic.usermount=1
chmod 0660 /dev/putter
usermod -G wheel <your username here>

Notes for OpenBSD in particular

While it still has some known issues, FUSE has actually made its way onto OpenBSD.

As of this writing, OpenBSD includes a BSD-licensed reimplementation of libfuse, and their own fuse kernel driver. It is available at better OpenBSD mirrors everywhere.

Keep in mind that if you want thread support (some Fuse filesystems do require it), the Perl build in OpenBSD 5.6 base does not support threads. Assuming you're not an OpenBSD ninja (or completely insane), I don't recommend trying to build your own and install it over the system Perl, because that can have bad repercussions. Use something like perlbrew if you want a threaded Perl:

perlbrew install perl-<version> -Dusethreads \
   --as perl-<version>_WITH_THREADS

For the tests, I recommend installing devel/p5-Lchown, devel/p5-Filesys-Statvfs, devel/p5-Unix-Mknod and devel/p5-Test-Pod from OpenBSD ports. (Or use the 'cpan' command from your Perlbrew-installed version to install those modules, if you want thread support like I was talking about above.)

Now, in your perl-fuse distribution, run:

perl Makefile.PL

You'll probably need to 'make test' as root. If you want to run your FUSE filesystem as non-root, run the following (as root):

sysctl kern.usermount=1
chmod 0660 /dev/fuse0

Now, you should be able to run 'make test'. Yes, there are a few test failures. No, those actually aren't our fault. Here are some things you should know about the state of FUSE on OpenBSD (the developer, Sylvestre Gallon, has been made aware of these):

  • There is a bug if a file is created in the fuse filesystem and goes away, then you create another file of the same name via FUSE and try to do utime(). Not sure if it's just utime() or if other things trip it too, but I discovered that via playing around. I THINK it's a vnode caching problem.
  • There is also a known issue with access() if all parent directories of a path haven't been explicitly accessed first.
  • There is a known issue with readdir() when supplying numbered dirents to support progressive readdir().
  • You should probably implement all of chown(), chmod(), truncate(), and utime() and/or utimens(). The kernel driver will mask out future setattr() requests if it gets ENOSYS from ANY of these. Oops.


This is contributed to the FUSE project by Mark Glines mark@glines.org, and is therefore subject to the same license and copyright as FUSE itself. It is released under LGPL 2.1. Please see the AUTHORS and COPYING files from the FUSE distribution for more information.