🚀 go-pugleaf

Dear All,

This is not an enquiry from a lazy bastard who isn't prepared to read a
book. It's regarding the relocation of ELF object (relocatable) files as
supported by Gnu C under later versions of Linux.

I am part way through implementing a dynamic linker for ELF object
files, but have hit upon a problem which won't go away. Unfortunately, I
do have ELF documentation, but either it is wrong, or my interpretation
leaves a lot to be desired.

At this stage, I'll give an outline of the problem to see if anyone's
interested in helping out, and a more detailed description when I'm sure
someone's listening.

So, here goes... The 'Relocation Section' gives me offsets into the text
section for function calls. When I add the text section offset onto the
offsets supplied for all the calls to a particular function, I theoretically
have the virtual locations in the object of all the calls to a particular
function. It is through writing an address to all the places where calls
exist for a particular function that the function can be relocated.

So far, so good. However, when I add the call offset in the Relocation
Section onto the text section offset, and put the correct address at the
resultant location, 'Segmentation Fault' is the helpful response that
Linux gives me.

To the best of my knowledge, I am following the documentation that I
have to the letter. (By the way, it is entitled simply "ELF", and is
released by Tool Interface Standards.)

Can anyone help? Does anyone have any other documentation? Does my
description of the problem highlight a flaw in my understanding of the
ELF format?

Any assistance would be greatly appreciated. (Oh, and by the way, thanks
for getting this far in what needed to be an overly long message.)

Clive Duffy.