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From: Markus Armbruster <armbru@redhat.com>
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Date: Mon, 17 Feb 2014 18:00:03 +0100
In-Reply-To: <530235F0.2040406@redhat.com> (Paolo Bonzini's message of "Mon,
	17 Feb 2014 17:16:48 +0100")
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Subject: Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert()
	failure
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Anthony Liguori <aliguori@amazon.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, Andreas Faerber <afaerber@suse.de>

Paolo Bonzini <pbonzini@redhat.com> writes:

> Il 17/02/2014 16:44, Stefan Hajnoczi ha scritto:
>>  }
>>
>> +static void sigabrt_handler(int signo)
>> +{
>> +    qtest_end();
>> +}
>> +
>
> void qtest_quit(QTestState *s)
> {
>     int status;
>
>     if (s->qemu_pid != -1) {
>         kill(s->qemu_pid, SIGTERM);
>         waitpid(s->qemu_pid, &status, 0);
>     }
>
>     close(s->fd);
>     close(s->qmp_fd);
>     g_string_free(s->rx, true);
>     g_free(s);
> }
>
> Not async-signal safe.  You need to ignore the g_string_free and
> g_free (perhaps even the closes) if calling from the sigabrt_handler.

kill(), waitpid() and close() are all async-signal-safe.

SIGABRT is normally synchronous enough: it's sent by abort().  But of
course, nothing stops the user from kill -ABRT.  Or GLib from calling
abort() in some place where an attempt to reenter it crashes & burns.
Not sure I'd care, but I'm pretty sure I don't care for freeing stuff on
exit :)