Re: [PATCH 2/3] core_pattern: allow passing of arguments to user mode helper when core_pattern is a pipe

From: Neil Horman
Date: Sun Jul 29 2007 - 08:19:45 EST


On Sun, Jul 29, 2007 at 11:34:18AM +0200, Martin Pitt wrote:
> Hi Neil,
>
> Neil Horman [2007-07-28 13:21 -0400]:
> > Jeremy asked that I make a patch next week to address split_argv's requirement
> > that the argc parameter be non-NULL. I'll be fixing that next week, and what I
> > can do is further enhance it such that it ignores spaces in quoted strings,
> > which should address the case that concerns you. I.E I can make split_argv
> > behave such that:
> > echo "|\"foo bar\" --pid %p" > /proc/sys/kernel/core_pattern
> > results in the following argv:
> > {{"foo bar"}, {"--pid"}, {"1234"}}
> >
> > Which I think handles what you are looking for.
>
> Oh, handling escaping and quoting is going to make it fairly
> complicated, but sure, if you need that for other things, too, that
> would solve the remaining case. I just wonder if, instead of
> implementing escaping, it wouldn't be easier to first split on spaces
> and then escape macros?
>
If it were just this case, then yes. But we also need to make this work
properly for when core_pattern is not a pipe. So the macro expansion routine
needs to be generalized somewhat. Certainly doable, it just takes a bit more
testing and care in coding. I'll start looking into it in the upcomming week.

> > Thank you for clearing me up on this. So it would seem we're ok with what we
> > have now, correct?
>
> Absolutely, yes.
>
> > We just have a potential corner case to address, which I can
> > reasonably handle with a modification to split_argv, that I have a
> > todo on next week.
>
> Right, it's really just for perfectionism. Spaces in executable names
> are EBW anyway, and readlink()ing /proc/<pid>/exe is much more robust
> anyway in terms of a small and orthogonal interface.
>
Understood.

> If the upstream kernel guys don't worry about it and consider it a
> blocker for merging, I don't either. :-)
>
Copy that

Thanks & Regards
Neil

> Thanks a lot,
>
> Martin
>
> --
> Martin Pitt http://www.piware.de
> Ubuntu Developer http://www.ubuntu.com
> Debian Developer http://www.debian.org



--
/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
*nhorman@xxxxxxxxxxxxx
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*http://pgp.mit.edu
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