setting adult pipelines reading named pipes but patience bash

i'm looking subprocess record descriptor uninterrupted given summons such open() does hang sharp side summons accept connection.

to demonstrate:

$ mkfifo /tmp/foobar.pipe
$ some_program --command-fd=5 5</tmp/foobar.pipe

in case, some_program run until slight /tmp/foobar.pipe open write; however, some_program useful effects even isn't receiving commands, preferred function some_program immediately executed.

mechanisms exec'ing by an swap scripting libel (python, perl, etc) c coupling open /tmp/foobar.pipe o_nonblock fall obvious; i'm looking pure-bash solution, should possible.