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Re: [PATCH/RFA] Don't relocate SunOS-style a.out dynamicexecutables
- From: Kevin Buettner <kevinb at redhat dot com>
- To: Mark Kettenis <kettenis at chello dot nl>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Tue, 24 Aug 2004 16:39:45 -0700
- Subject: Re: [PATCH/RFA] Don't relocate SunOS-style a.out dynamicexecutables
- Organization: Red Hat
- References: <200408221856.i7MIuYAT034596@elgar.kettenis.dyndns.org>
On Sun, 22 Aug 2004 20:56:34 +0200 (CEST)
Mark Kettenis <kettenis@chello.nl> wrote:
> Since I was curious whether our SunOS-style a.out shared library
> support still worked, I fired up my virtual VAX[1] and installed
> NetBSD 1.5.2 on it. Alas, GDB didn't quite work, and indeed the
> solib-sunos.c code is to blame. Some debugging revealed that the code
> was relocating the main executable over two bytes. If you know a bit
> about the VAX and look at the code it is pretty easy to see why. VAX
> functions start at an offset of two bytes from the function's address.
Those two bytes are a register save mask? (Not that it matters; just
trying to remember something that I knew a very long time ago.)
> The code in sunos-solib.c:sunos_relocate_main_executable() compares
> the PC with the entry point as recorded in the executable. Since
> these differ by two bytes, the code relocates the main executable over
> those two bytes.
>
> The easiest way to solve the problem would be to rip out the code that
> tries to relocate the executable. AFAIK SunOS-style a.out executable
> aren't relocatable. This code is probably just a leftover from when
> the SunOS code was split out of the SVR4 code. Is that right?
That sounds like a reasonable guess to me. FWIW, I did test the code
after the split, but I tested it on an old SunOS (sparc architecture)
system.
> If so, I'd like to apply the attached patch.
Sure. It's okay with me.
Kevin