Re: ping: [patch 1/6] PIE: Attach binary even after re-prelinked underneath

[Joel Brobecker <brobecker at adacore dot com>]

> gdb/
> 2010-07-02  Jan Kratochvil  <jan.kratochvil@redhat.com>
> 	    Joel Brobecker  <brobecker@adacore.com>
> 
> 	Fix attaching to PIEs prelinked on the disk after the process was
> 	started.
> 	* solib-svr4.c (svr4_exec_displacement): New variable arch_size.
> 	Verify it against bfd_get_arch_size.  Try to match arbitrary
> 	displacement for the phdrs comparison.
> 
> gdb/testsuite/
> 2010-07-02  Jan Kratochvil  <jan.kratochvil@redhat.com>
> 	    Joel Brobecker  <brobecker@adacore.com>
> 
> 	* gdb.base/break-interp.exp: Run $binpie with new value "ATTACH", new
> 	code for it.  New variable relink_args.
> 	(prelinkYES): Call prelinkNO.
> 	(test_attach): Accept new parameter relink_args.  Re-prelink the binary
> 	in such case.  Move the core code to ...
> 	(test_attach_gdb): ... a new function.  Send GDB command "file".
> 	Extend expected "Attaching to " string.

This is OK, with one English error in one of my suggestions (mea culpa).
I also still have a question, but this should not prevent the patch to
go in as is.

> +	      /* DISPLACEMENT could be found easier by the difference of
                                             ^^^^^^ more easily

Same thing for the 64bit case.

> +		  /* PT_GNU_STACK is an exception by being never relocated by
> +		     prelink as its addresses are always zero.  */

I understand why you mean, now, about the PT_GNU_STACK entry not being
changed during the prelink.  But I don't get the relationship between
this comment and the code surrounding it. Can you explain that?

-- 
Joel