Bug#733452: init system daemon readiness protocol

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

(Sorry, 2nd copy here because I missed up the change of To field in
the previous one.)

cameron writes ("Re: Bug#733452: init system daemon readiness protocol"):
> I was curious: why should SOCK_STREAM be used instead of SOCK_DGRAM in 
> your proposed protocol?

SOCK_DGRAM sockets do not offer reliable delivery (at least, not on
all unices).

> Have you seen Lennart Poettering's pastebin of a short daemon side 
> implementation of that protocol: http://fpaste.org/64821/32737713/? It 
> meets all your desired criteria, it is used in one init system already, 
> and it is very extensible. Now that you know that systemd does not 
> actually use SOCK_SEQPACKET, but SOCK_DGRAM, do you have any changes in 
> opinion of the systemd approach?

I still think it would be simpler to pass the ready-connected socket
(or whatever) to the daemon by inheritance, rather than having the
daemon call socket() etc.

Do you know why in systemd it was done the way it was ?

Thanks,
Ian.