there is a package on openbsd ports. it's outdated. don't use it.

    $ git clone https://github.com/unofficial-mirror/u9fs
    $ cd u9fs


apply this patch:

    diff --git a/u9fs.c b/u9fs.c
    index ea0391c..48e1e21 100644
    --- a/u9fs.c
    +++ b/u9fs.c
    ` -152,9 +152,9 ` char*       root;
     User*  none;
     Auth *authmethods[] = {        /* first is default */
    +       &authnone,
            &authrhosts,
            &authp9any,
    -       &authnone,
     };
     Auth *auth;


and build it:

    $ make
    $ doas make install


and add this to /etc/inetd.conf:

    564     stream  tcp     nowait  root    /usr/local/bin/u9fs -l /var/log/u9fs.log /path/to/share


this runs a 9p server on port 564 (default) and reads from `/path/to/share`.

now enable and run inetd:

    $ doas rcctl enable inetd
    $ doas rcctl start inetd