Re: [PATCH] PIE support for OpenBSD

[Stan Shebs <stanshebs@earthlink.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