objcopy --extract-symbol option keeping bogus sections/segments : wrong?

[Vincent Rubiolo <vincent dot rubiolo at windriver dot com>]

Hello again,

I am pinging again since my message might have been overlooked.

Thanks for your suggestions,

Vincent

Vincent Rubiolo wrote:
> Hi gentle binutils maintainers,
>
> I am writing to you about the newly added --extract-symbol of objcopy 
> (cf [1]) which, as Richard explained, we use to extract symbol files 
> from VxWorks kernels.
>
> My concern is about the fact that the option zeroes out the 
> addresses/sizes, etc of the sections and segments in the file _instead_ 
> of only keeping the relevant bits in. In some circumstances, this 
> confuses our kernel loader (which is used to load that stripped file) 
> since the segments within the file are marked as loadable but are of 
> empty size/address.
>
> I have looked at the ELF spec [2] and while the standard says the image 
> can have supplementary segments/sections, it does not specify whether 
> they can be empty/marked PT_LOAD.
>
> To me, there is no reason to have these bogus sections/segments in the 
> image and they should be removed. I think we should fix the file and not 
> the loader itself.
>
> Is this a correct reasoning?
>
> Thanks for your insight.
>
> Vincent
>
> PS: attaching readelf output on VxWorks symbol files
>
> [1] http://sourceware.org/ml/binutils/2007-03/msg00004.html
> [2] http://www.sco.com/developers/gabi/latest/contents.html

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