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From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: elfutils-devel@lists.fedorahosted.org
Subject: Re: [PATCH] Add --core-pattern option to eu-stack
Date: Thu, 27 Nov 2014 22:41:30 +0100
Message-ID: <20141127214130.GA29584@host2.jankratochvil.net>
In-Reply-To: 1417086351.4954.40.camel@bordewijk.wildebeest.org

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On Thu, 27 Nov 2014 12:05:51 +0100, Mark Wielaard wrote:
> We have -o,--output support in other utilities.

Those are ld, strip and unstrip.  That is not for text output but for the
resulting ELF files which is IMO a different case.

BTW I am not against it, I just find it redundant.  If thiAny program could
have -o|--output but in UNIX it is solved by the more general shell '>'.


> But maybe it isn't
> useful in general and people will always use shell redirection?

Currently it uses fopen "wx" which requires unique filename for each crash
dump unwind.  One could use %p in the filename but that is also not complet=
ely
unique.  Besides that one should IMO provide more information from /proc/PI=
D/
(like fd/ ) than just the backtrace eu-stack can provide.  One is also
interested in /proc/PID/exe which is not obvious from -l or -m (at least for
PIEs); although one could possibly use %E for core_pattern.

I just find it improbable one would not need a single other kind of
information than what eu-stack can provide.


> But if --core-pattern isn't useful without other code, then we should
> include that code too.

Yes, there could be provided some "contrib"-like core dumping shell script.


> Could you post what you have?

Nothing interesting, only for debugging eu-stack --core-pattern, when you a=
sk:
	#! /bin/bash
	exec >>/tmp/out 2>>/tmp/out
	date --iso=3Dseconds
	echo "$*"
	cd /home/jkratoch/redhat/elfutils
	. /home/jkratoch/t/elfutils-boot
	ldd ./src/stack
	# It locks up as strace holds fd 0:
	#strace -s200 -o /tmp/out.strace -q ./src/stack --core-pattern -1 --pid=3D=
$1
	exec ./src/stack --core-pattern -1 -l -m --pid=3D$1


Jan

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