Re: [Qemu-devel] [PATCH v2 17/19] linux-user: Use both si_code and si_signo when converting siginfo_t

[Peter Maydell]

On 7 June 2016 at 20:22, Laurent Vivier <address@hidden> wrote:
> Where is coming from QEMU_SI_TIMER?
> It is not used elsewhere.

It's the enum constant that goes with "we use the
.sifields.timer fields of the union". At the moment we
don't have any cases which cause us to think we should
use those (and we didn't before this patch either), so
the case in this case statement is purely for completeness.
(I suspect the _timer fields are wrong anyway, since they're
pretty much dead code.)

The awkward thing about SI_TIMER is that because glibc
can call rt_sigqueueinfo() with a si_code of SI_TIMER[*] we
have no way to tell "this is a SI_TIMER signal from
the kernel with valid .timer fields" from "this is a
SI_TIMER from rt_sigqueueinfo with valid .rt fields".
So we assume it's always the latter.

[*] for instance, see thread_expire_timer() in
http://osxr.org:8080/glibc/source/nptl/sysdeps/pthread/timer_routines.c

thanks
-- PMM