Re: [ECOS] select() and signal's

["Boris V. Guzhov" <borg at int dot spb dot ru>]

I tried and it works. But there are some questions.
Now pthread_kill() interrupts not only select(), but
also sem_wait().
As far as I know, the POSIX semaphores are a general and
exclusive synchronization mechanism with a signal-cathing
function. And their functions should not be interrupted by
signals.
In Linux inplementation pthread_kill() not interrupts
the sem_wait().

That's right?

--
Boris Guzhov,
St.Petersburg, Russia



> "Boris V. Guzhov" wrote:
> >
> > But it still not works.
> > Both threads have an equal priority.
> > I carefully has looked on cyg_sigqueue() code.
> > And I don't understand as cyg_sigqueue() function will wake
> > the blocked  in select() thread.
> > The cyg_sigqueue() function  calls only  signal_sigwait.broadcast().
> > But the blocked thread sleeps on other condition variable - selwait,
> > but not on signal_sigwait.
>
> Try the attached patch and let me know how you get on. I've only done some
> simple tests. But I want you to try it with your existing code rather than
> me spending more time on it[1]. *Do* let me know the outcome.
>
> Jifl
>
> [1] Since you're not a customer :)
> --
> Red Hat, Rustat House, Clifton Road, Cambridge, UK. Tel: +44 (1223) 271062
> Maybe this world is another planet's Hell -Aldous Huxley || Opinions==mine


----------------------------------------------------------------------------
----


> ? foo
> Index: signal.cxx
> ===================================================================
> RCS file: /home/cvs/ecc/ecc/compat/posix/current/src/signal.cxx,v
> retrieving revision 1.11
> diff -u -5 -p -r1.11 signal.cxx
> --- signal.cxx 2001/02/14 01:25:44 1.11
> +++ signal.cxx 2001/04/20 20:08:54
> @@ -61,12 +61,13 @@
>  #include <signal.h>                     // our header
>  #include <setjmp.h>
>  #include <unistd.h>                     // _exit
>
>  #include <cyg/kernel/clock.hxx>
> -
> +#include <cyg/kernel/thread.hxx>
>  #include <cyg/kernel/clock.inl>
> +#include <cyg/kernel/thread.inl>
>
>

// -------------------------------------------------------------------------
>  // Internal definitions
>
>  // Handle entry to a signal package function.
> @@ -239,16 +240,33 @@ cyg_bool cyg_sigqueue( const struct sige
>          ss->pending = si;
>      }
>      // else A non-queuable signal, just set it pending
>
>      if( thread != NULL )
> +    {
>          sigaddset( &thread->sigpending, signo );
> -    else sigaddset( &sig_pending, signo );
> +        // just wake the thread up now if it's blocked somewhere
> +        if ((thread->sigpending & ~thread->sigmask) != 0)
> +        {
> +            thread->thread->set_asr_pending();
> +            thread->thread->release();
> +        }
> +    }
> +    else
> +    {
> +        sigaddset( &sig_pending, signo );
> +        // Wake up any threads in sigsuspend() and sigwait().
> +        if (!signal_sigwait.get_queue()->empty())
> +        {
> +            signal_sigwait.broadcast();
> +        }
> +        else
> +        {
> +            cyg_posix_pthread_release_thread( &sig_pending );
> +        }
> +    }
>
> -    // Wake up any threads in sigsuspend() and sigwait().
> -    signal_sigwait.broadcast();
> -
>      if( !locked ) signal_mutex.unlock();
>
>      return true;
>  }
>
>