but don't know how flexible we are in
terms of adding S_IFBPF to the UAPI.
I don't think it should be a problem. You referred to POSIX Standard in
your other mail but I can't see any reason why not to establish a new
file mode. Anyway, FreeBSD (e.g. whiteouts) and Solaris (e.g. Doors,
Event Ports) are just examples of new modes being added.
mknod /bpf/map/1 m 1 1
:)
Yes, maybe I think this is a better solution architectural instead of
constructing a new filesystem.
Yeah, also 'man 2 stat' lists a couple of others used by various systems.
The pro's of this approach would be that no new file system would be needed
and the special inode could be placed on top of any 'regular' file system
that would support special files. I do like that as well.
I'm wondering whether this would prevent us in future from opening access
to shell tools etc on that special file, but probably one could provide a
default set of file ops via init_special_inode() that could be overloaded
by the underlying fs if required.