Re: What is ptrace flag PT_TRACESYSGOOD for?

[Jeff Dike]

On Tue, Mar 14, 2006 at 05:26:52AM -0500, Chuck Ebbert wrote:
> I am trying to document PTRACE_SETOPTIONS and I can't figure out what
> the option PTRACE_O_TRACESYSGOOD is used for.

It makes it easier to distinguish between the child receiving a
SIGTRAP and making a system call.  On x86, without TRACESYSGOOD, you
can see if orig_eax == -1 to check for a real SIGTRAP.  I'm not sure
about the other arches, but it's nice to have an arch-independent way
of doing it, even if there are equivalents in every arch.

				Jeff
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