Re: [Tails-dev] Improvement of the shutdown sequence

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Autor: intrigeri
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Para: The Tails public development discussion list
Novos Tópicos: [Tails-dev] memlockd stopped too soon (was: Improvement of the shutdown sequence)
Assunto: Re: [Tails-dev] Improvement of the shutdown sequence
Hi,

Ague Mill wrote (20 May 2012 17:55:03 GMT) :
> I have noticed that there is some seconds in the shutdown sequence
> that might be wasted by properly shutting down services that we
> don't care much about.


I don't object to this work being done, but I'd like to make sure we
carefully balance what looks to me like a pretty tiny gain (a few
seconds in the non-emergency shutdown sequence) against the need to
prepare, test and maintain the hacks that would implement the removal
of a bunch of shutdown scripts. Arguably, the needed hack is trivial,
so we can probably take the risk: if this becomes a maintenance mess
in the future, nothing prevents us from removing the hacks.

> Here is the current init scripts that are currently called (same
> scripts and order for shutdown and reboot sequences) in Tails 0.11
> and an analysis of what might be removed:


This analysis looks correct to me.

>  * memlockd
>    Stop memlockd. Memwipe files will not kept in memory after that.
>    Better let sendsigs kill it, or even, add its PID to
>    /var/run/sendsigs.omit. **Remove**


Something has to be done in this area to fix what looks like a serious
bug, independently of the optimization of the shutdown sequence speed.
The sendsigs.omit way looks right: we really don't want these files
unmapped from memory until tails-kexec has had a chance to do its
work. Are you taking care of that one?

> Any advice on how to implement the removal of those extra scripts?
> A hook with a bunch of `rm` commands? It looks like `update-rc.d` really
> wants to have shutdown scripts in place...


`rm' looks good enough.

Cheers,
--
intrigeri
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