Re: [PATCH] PIE support for OpenBSD

[Stan Shebs <stanshebs at earthlink dot net>]

On 12/22/11 2:20 AM, Mark Kettenis wrote:
> > Date: Wed, 21 Dec 2011 15:39:04 -0800
> > From: Stan Shebs<stanshebs@earthlink.net>
> >
> > On 12/21/11 1:26 PM, Mark Kettenis wrote:
> > > > Date: Wed, 21 Dec 2011 18:13:15 +0100
> > > > From: Jan Kratochvil<jan.kratochvil@redhat.com>
> > > >
> > > > On Sat, 17 Dec 2011 22:08:29 +0100, Mark Kettenis wrote:
> > > > > For now this is OpenBSD-specific, but FreeBSD and NetBSD might
> > > > > implement the PIOD_READ_AUXV request at some point too.
> > > > [...]
> > > > > 	* inf-ptrace.c [PT_IO&&   PIOD_READ_AUXV]
> > > > So why didn't you put it into *bsd*-nat.c files?
> > > There is already PT_IO support code in inf-ptrace.c.  It makes sense
> > > to keep it all together.  I guess I could move all that code into a
> > > seperate bsd-nat.c file, but that's quite a big undertaking.  And
> > > inf-ptrace.c *BSD really is the primary user of inf-ptrace.c anyway.
> > > The various Linux targets only need it to support ancient versions of
> > > the Linux kernels; linux-nat.c ovverrides everything except for
> > > to_fetch_registers and to_store_registers.  And those are overridden
> > > by most, if not all, *-linux-nat.c files.
> > I wonder if inf-ptrace.c could be retired altogether.  It was always
> > based on a weak assumption, that Unix variants would tend to have the
> > same syntax and semantics for the various ptrace commands, and I suspect
> > that more of its code is unreachable than is obvious from inspection,
> > what with configs overriding or on the verge of being retired themselves.
> Almost all of the code is used on OpenBSD and the other BSDs.  It is
> certainly true that systems have diverged.  This is especially true
> for Linux where we have a lot of support code for dealing with threads
> that sits on top of the code in inf-ptrace.c.  It still uses a fair
> chunk of the code through linux_ops->to_create_inferior, to_attach,
> to_detach and to_stop, to_resume and to_mourn_inferior, as pointed out
> by Jan.  But I currently do see inf-ptrace.c primarily as BSD support
> code and further decoupling the Linux code might make some sense.  But
> you'd need to duplicate a fair amount of code to fully decouple
> to_create_inferior for example.
>
> Back to my origional diff.  Any remaining objections to committing it as is?

Looks fine to me.  It would be helpful to mention somewhere in the 
vicinity of the #if's that the code is BSD-specific or BSDish, so as to 
forestall people hunting around in other OS headers wondering if those 
macros are defined or not.

Stan