Re: [uml-devel] Re: [RFC] PATCH 3/4 - Time virtualization : PTRACE_SYSCALL_MASK

["Charles P. Wright" <cwright@cs.sunysb.edu>]

On Wed, 2006-04-26 at 15:40 -0400, Jeff Dike wrote:
> On Wed, Apr 26, 2006 at 04:26:42PM -0400, Charles P. Wright wrote:
> > I have a similar local patch that I've been using.  I think it would be
> > worthwhile to have an extra bit in the bitmap that says what to do with
> > calls that fall outside the range [0, __NR_syscall].  That way the
> > ptrace monitor can decide whether it is useful to get informed of these
> > "bogus" calls.
> 
> The bit needs to be somewhere, but I think sticking it in the syscall
> bitmask is a bad idea.  Mixing apples and oranges, as it were.
> Sticking it in the op is better, even though that's a bit of apples
> and oranges as well.
> 
> Another alternative would be to make it an option and set it with
> PTRACE_SETOPTIONS.
That is probably a better solution than sticking it in the request (I
assume you meant request by op).   I think spawning more PTRACE_*
requests that perform some permutation of PTRACE_SYSCALL is likely to
make things confusing.

Charles