Fifo files on 4.2?

[Doug Gwyn <gwyn>]

> Does anyone have a (preferably user level) way to implement sys5 type
> fifo files on 4.2 bsd?  If I understand the concept correctly, this would
> be exactly what I have wanted at many different times (as well as now).
> 
> It seems that it could be done somehow with sockets, but I freely admit that
> I haven't had to understand them yet and don't.

I once looked at this and decided that sockets would not suffice.
For one thing, FIFO inodes are stored in the file system so they
persist across reboots.  For another, the 4.2BSD UNIX domain socket
code was so buggy that one endangers his system by trying to use it.

Fortunately, the S_IFIFO bit pattern has not been usurped by Berkeley
yet, so FIFOs could be added to the 4.nBSD kernel without disrupting
things.  (It would be nice if pipes were put back at the same time.)