I also rewoke this LKML thread https://lore.kernel.org/kernel-hardening/01e72780-e328-23b5-... a few months back, because my one quibble with CloudABI is its all-singing-all-dancing fork+exec abi.

Making an embryonic process, mutating it's state as desired, and then submitting to the scheduler is a much nicer workflow, and more in the spirit of capabilities anyways where "fork = duplicate the whole keyring and then destroy some caps" as foolhardy.

FreeBSD already had process/PID FDs, but I think CloudABI avoided them because it wanted to be easier to port. But now that Linux has them too, I don't think this should be a such a portability concern.