Re: Problem with getExe and testInsertedBreakpoint

[Phil Muldoon <pmuldoon@redhat.com>]

Mark Wielaard wrote:
> Hi Phil,
>
> On Thu, 2007-07-26 at 14:32 -0500, Phil Muldoon wrote:
>   
>
> Aha, that also explains the meaning of the new kernel /proc/sys sysctrl
> parameters fs.binfmt_elf.dumpwhole_segments to get all text sections
> included and fs.binfmt_elf.dump_elf_headers to get partial text sections
> that I saw Roland added. Does fcore have some similar parameters?
>
>   

Yup, fcore -a dump all possible segments. However that is not the 
default. That has been there since fcore was written because I perhaps 
made the brave assumption that in userland core dumps we can hang around 
and dump more segments as the process is "fine". In kernel core dumps I 
think the aim it so do this all as quickly as possible and clobber the 
process.


> Right, and elf_prpsinfo only allows for truncated executable names (16
> chars). Bleah. So something like BuildID is really badly needed to
> present the user with something that is more often usable I guess. I saw
> that the BuildID support proposal was approved as one of the Fedora 8
> Features: http://fedoraproject.org/wiki/Releases/FeatureBuildId
> http://fedoraproject.org/wiki/Releases/8/FeatureList
> Will it be possible for frysk to also support that in the Fedora 8
> timeframe?
>
>   


Given that there is a lot to do, and not enough of us to do it, I've 
taken the rather (perhaps cheeky) approach of letting Jan and Roland 
thrash out the details, then pick it up and incorporate it when done. I 
already owe a Roland an answer to the partially elided segment question 
and Frysk.


> OK, and I assume the same would be true for any code segments that were
> altered through ptrace poke?
>
>   

I'm not sure of kernel mechanics. The core dump class just looks at the 
the bits in /proc/$$/maps to see if it has been written to.

> Thanks. I filed bug #4852 to clean up the code where I abused it and
> will go through the other stuff in the core listed there that uses the
> wrong approach (I know I just copied what I did from some other existing
> example, so it is good to get this fully cleaned up).
>
>   
>> Hope that helps!
>>     
>
> It helped greatly. Thanks for sharing. Some of the things you said
> suddenly made me see the bigger picture and connect the dots.
>
>   

Awesome, glad to be of help

Regards

Phil