Re: Why I want PTRACE_O_TRACESTOP option

[Denys Vlasenko]

On Friday 09 September 2011 02:18, Tejun Heo wrote:
> Hello, Denys.
> 
> On Thu, Sep 08, 2011 at 06:50:01PM +0200, Denys Vlasenko wrote:
> > Consider what will happen when a next ptrace fix will require
> > a way to change ptrace API at runtime. A new option will likely
> > be introduced, say, PTRACE_O_TRACEPONY, with next available
> > bit position 7, and perhaps some new event will be generated,
> > PTRACE_EVENT_PONY, with value.... yes, it can't be 7,
> > PTRACE_EVENT_STOP took it. So it will probably be 8.
> 
> Then, just give it the next matching number.
> 
> If options naturally happen to match the events, that's a nice
> coincidence.  If the real life requirement deviates from the beautiful
> one-to-one mapping, then, so be it.  No, the magical contiguous one to
> one mapping isn't the most important design concern.
> 
> To me, the rationale presented here almost argues against
> PTRACE_O_TRACESTOP.  :(

How about changing PTRACE_EVENT_STOP value to, say, 255 then,
in order to move it away from (option,event) area?

-- 
vda
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/