:: Re: [DNG] Reaping orphan processes.
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Author: Rainer Weikusat
To: dng
Subject: Re: [DNG] Reaping orphan processes.
Didier Kryn <kryn@???> writes:
> Le 07/03/2023 à 23:51, capercally.bleery670@??? a écrit :
>> On Tue, Mar 07, 2023 at 03:22:53PM +0000, Rainer Weikusat via Dng wrote:
>>>> Traditionally, this type of daemon would remain in foreground until it
>>>> was functional, and then doublefork itself, at which time sysvinit
>>>> would run the next daemon.
>>> That's an urban myth. There is no such convention and "daemon readiness"
>>> isn't a well-defined concept. Current implementations of SysV-RC start
>>> jobs in parallell (and have for some time).
>> The traditional symlinks and sequence numbers are still there, though.
>> What purpose do they serve, then? At what point does rc proceed from
>> handling /etc/rc2.d/S02unbound to /etc/rc2.d/S03cron ? (or is there such
>> a distinct point at all?)
>     Symlinks are intermediaries used ot handle the "system
> levels". Sysvinit manages a number of system levels from 0 to 6, each
> of which is dedicated to some mode of operation. Some services are
> started when entering a run level and some are stopped when quitting
> it. Each rcx.d directory contains S symlinks to start services and K
> symlinks to stop them. The numbers tell the order but are convoluted
> with the comments in the header of the scripts which is a
> meta-language explicitating their relationships.

Not really. If the scripts use LSB headers to declare dependencies, the
insserv program generates symlinks with appropriate sequence numbers
from the declared dependencies. Whether or not these are actually used
for start/ stop ordering depends on the boot mode of the system, see
other e-mail.