preventing FIFO from EOF

[rihad]

$ mkfifo /var/tmp/foo
$ buffer -i /var/tmp/foo                    # misc/buffer
# in another console:
$ echo hi > /var/tmp/foo

buffer prints hi and exits. I want it to keep reading and printing 
indefinitely.

Further experimentation revealed that I need two writers: one dummy 
writer that just keeps /var/tmp/foo open for writing, and the other 
doing the "real work". This way buffer wouldn't exit. But how to emulate 
the dummy writer? It itself needs to block on something to keep 
/var/tmp/foo open. Any clean way to do this in shell? Maybe the solution 
is quite simple but isn't at the tip of my tongue.

Thanks.