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Date: Fri, 06 Jun 2014 11:48:33 +0200
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Subject: Re: [Qemu-devel] [PATCH v2] linux-user/signal.c: define
 __SIGRTMIN/MAX for non-GNU platforms
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To: Riku Voipio <riku.voipio@iki.fi>, Natanael Copa <ncopa@alpinelinux.org>
Cc: qemu-devel@nongnu.org

Il 06/06/2014 10:27, Riku Voipio ha scritto:
> Hi,
>
> On Wed, Jun 04, 2014 at 09:49:00AM +0200, Natanael Copa wrote:
>> The __SIGRTMIN and __SIGRTMAX are glibc internals and are not available
>> on all platforms, so we define those if they are missing. We also check
>> that those corresponds with the posix variables SIGRTMIN/SIGRTMAX which
>> may only be available during runtime.
>>
>> This is needed for musl libc.
>
> After all, the idea of asserts doesn't work on glibc it seems:
>
> qemu-arm qemu-smoke/armel/busybox ls -ld .
> qemu-arm: linux-user/signal.c:393: signal_init: Assertion `32 == (__libc_current_sigrtmin ())' failed.
> Aborted
>
> Quick test on my amd64/glibc 2.18 system:
>
> printf("RTMIN: %d RTMAX: %d\n", SIGRTMIN, SIGRTMAX);
> RTMIN: 34 RTMAX: 64
>
> While: /usr/include/bits/signum.h
> #define __SIGRTMIN  32

That's because glibc reserves two signals (one for cancellation, the 
other to implement set*id system calls).  Basically you'd need to extend 
the hack of host_to_target_signal_table to all signals in the 
[__SIGRTMIN, SIGRTMIN) range, computing the table at run-time.

Paolo