Subject: Re: power management and related concerns
To: Garrett D'Amore <>
From: Thomas E. Spanjaard <>
List: tech-kern
Date: 07/01/2006 19:57:18
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Garrett D'Amore wrote:
> Thomas E. Spanjaard wrote:
>>Steven M. Bellovin wrote:
>>>On Sat, 01 Jul 2006 13:18:27 +0000, "Thomas E. Spanjaard"
>>><> wrote:
>>>>Steven M. Bellovin wrote:
>>>>>    temp=acpitemp     >70*2       /bin/shutdown -p now
>>>>>where the *2 indicates that it has to happen twice in a row.  A few
>>>>>frills, like shell variables for each config line -- the 'temp'
>>>>>means that
>>>>>a script would be run with envstatd_temp set to the value.  A | at the
>>>>>start of the command would create a pipeline that would be fed the
>>>>>on stdin, to permit easy real-time graphing programs.
>>>>Confusing, using mathematical symbols for other meanings. Isn't the
>>>>how-many-times-or-how-long (as Jachym Holecek suggested) better off
>>>>in a separate column (think inetd.conf syntax)? Come to think of it,
>>>>inetd.conf is a viable example format for this.
>>>I thought about that; it's certainly one perspective.  Here, though, I
>>>assumed that it would rarely be used, in which case I'm imposing a
>>>on everything else.  The other option is something like '-n 2', but that
>>>might be even more confusing.
>>Hmm, but a crontab is similar to this as well, but allows you to use *
>>in separate columns (so no binary operator use is associated with the
>>symbol due to obvious distance between columns) in the case where you
>>don't want to specify anything specific.
> Rather than go down the path of inventing a new format, why not just put
> this in XML.  The code lives in userland, so an XML parser isn't too big
> a deal.   Plus you get all the extensibility, etc.

I find XML to be an awkward format for configuration files, like Chapman 
Flack and Jachym Holecek already said. It might be good if a human never 
directly edits it, but in this case I think it's safe to assume vi will 
be the firstmost tool to edit it (as it's in base).

> As far as extensible interface from sysmon to powerd, I rather like the
> idea of sending property lists, but I would prefer to use some kind of
> packed format.  I don't want to force the kernel to pack up XML just to
> send messages to userland.

Though I'm not clued on the property list jizz, what's the problem of 
using an ioctl like virtually every other application on BSD uses for 
these kind of interactions with the kernel?

         Thomas E. Spanjaard

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