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Date: Thu, 09 Jun 2011 07:59:09 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] sigfd: use pthread_sigmask
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To: Alexander Graf <agraf@suse.de>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, =?UTF-8?B?QW5kcmVhcyBG?= =?UTF-8?B?w6RyYmVy?= <andreas.faerber@web.de>, qemu-devel Developers <qemu-devel@nongnu.org>

On 06/09/2011 12:55 AM, Alexander Graf wrote:
> Qemu uses signalfd to figure out, if a signal occured without the need
> to actually receive the signal. Instead, it can read from the fd to rec=
eive
> its news.
>
> Now, we obviously don't always have signalfd around. Especially not on
> non-Linux systems. So what we do there is that we create a new thread,
> block that thread on all signals and simply call sigwait to wait for a
> signal we're interested in to occur.
>
> This all sounds great, but what we're really doing is:
>
>      sigset_t all;
>
>      sigfillset(&all);
>      sigprocmask(SIG_BLOCK,&all, NULL);
>
> which - on Darwin - blocks all signals on the current_process_, not onl=
y
> on the current thread. To block signals on the thread, we can use
> pthread_sigmask().
>
> This patch does that, assuming that my above analysis is correct, and t=
hus
> renders Qemu useable on Darwin again.
>
> Reported-by: Andreas F=C3=A4rber<andreas.faerber@web.de>
> CC: Paolo Bonzini<pbonzini@redhat.com>
> CC: Jan Kiszka<jan.kiszka@siemens.com>
> CC: Anthony Liguori<anthony@codemonkey.ws>
> Signed-off-by: Alexander Graf<agraf@suse.de>

Acked-by: Paolo Bonizni <pbonzini@redhat.com>

Paolo