POSIX signal handling
Sérgio Santos
Sergio.santos at skysoft.pt
Tue Mar 31 17:47:59 UTC 2009
And now the handler executes just fine in the example!! So thank you for that!
I have to let until tomorrow a more complete analysis (in terms of our app instead of the example). I will then post our comments (if any!).
Best regards,
Sérgio
> -----Original Message-----
> From: Joel Sherrill [mailto:joel.sherrill at OARcorp.com]
> Sent: terça-feira, 31 de Março de 2009 17:06
> To: Sérgio Santos
> Cc: rtems-users at rtems.com
> Subject: Re: POSIX signal handling
>
> How about this version?
>
> RTEMS is multi-threaded within a single process and no thread
> had ever enabled SIGALRM.
>
> This MIGHT be a buglet in relation to the default signal mask
> but we would have to consult the Open Group specification to
> be sure.
>
> Sérgio Santos wrote:
> > Thanks again for your kind answer.
> >
> > Actually we've had that very output... since the beginning :)
> > Ever since the problem for us is we're expecting not the signal to be
> pending, but otherwise that the handler *sig_handler* runs when the signal
> is received!
> >
> > We're running the same code, and - glad to know by comparing - no
> problems coming from our makefile. So we'd expect something like the
> output in Linux (every second):
> >
> > [sbrotas at imaserver2 sigact]$ ./sigact
> > HANDLER: caught SIGALRM
> > SIGALRM not pending :)
> >
> > HANDLER: caught SIGALRM
> > SIGALRM not pending :)
> >
> > ^C
> > [sbrotas at imaserver2 sigact]$
> >
> > ---
> > Best Regards
> > Sérgio
> >
> >
> >
> >
> >> -----Original Message-----
> >> From: Joel Sherrill [mailto:joel.sherrill at OARcorp.com]
> >> Sent: terça-feira, 31 de Março de 2009 14:11
> >> To: Sérgio Santos
> >> Cc: rtems-users at rtems.com
> >> Subject: Re: POSIX signal handling
> >>
> >> Sérgio Santos wrote:
> >>
> >>> Hi, Joel
> >>> I'm using qemu (mostly) but have tried running directly on the target
> >>>
> >> too.
> >>
> >>> Our current guess is some build configuration conflict or mistake, but
> >>>
> >> we're still to find what exactly. Still, we haven't debugged much for
> some
> >> clues or looked at the rtems code.
> >>
> >> Runs for me. I attached my version of your code and the
> >> Makefile.
> >>
> >> Built on an installed BSP like this:
> >>
> >>
> >> RTEMS_MAKEFILE_PATH=/home/joel/rtems-4.10-work/bsp-install/i386-
> >> rtems4.10/pc386
> >> make clean all
> >>
> >> [joel at iceland sigaction]$ runqemu -i */*exe
> >> Running o-optimize/sigaction.exe
> >> Could not open '/dev/kqemu' - QEMU acceleration layer not activated: No
> >> such file or directory
> >> SIGALRM is pending
> >>
> >> SIGALRM is pending
> >>
> >> SIGALRM is pending
> >>
> >> SIGALRM is pending
> >>
> >> SIGALRM is pending
> >>
> >> SIGALRM is pending
> >>
> >> /home/joel/bin/runqemu: line 65: 15963 Killed ${QEMU}
> >> ${ARGS}
> >> Could not open '/dev/kqemu' - QEMU acceleration layer not activated: No
> >> such file or directory
> >> SIGALRM is pending
> >>
> >>
> >>> Our option is now getting closer to drop POSIX and go for the RTEMS
> >>>
> >> classic API on the async signals matter in particular, and for the port
> of
> >> our Linux app overall. Still we'll report any findings.
> >>
> >>>
> >>> Thank you much
> >>>
> >>> Sérgio
> >>>
> >>>
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Joel Sherrill [mailto:joel.sherrill at OARcorp.com]
> >>>> Sent: segunda-feira, 30 de Março de 2009 20:30
> >>>> To: Sérgio Santos
> >>>> Cc: rtems-users at rtems.com
> >>>> Subject: Re: POSIX signal handling
> >>>>
> >>>> Sérgio Santos wrote:
> >>>>
> >>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Joel Sherrill [mailto:joel.sherrill at OARcorp.com]
> >>>>>> Sent: segunda-feira, 30 de Março de 2009 19:11
> >>>>>> To: Sérgio Santos
> >>>>>> Cc: rtems-users at rtems.com
> >>>>>> Subject: Re: POSIX signal handling
> >>>>>>
> >>>>>> Sergios,
> >>>>>>
> >>>>>> I meant to ask.. Is it ok to include this in the RTEMS examples
> >>>>>> as a simple example of alarm and signals?
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> Joel,
> >>>>>
> >>>>> Sure! Can't help feeling it's a privilege, despite the simplicity of
> >>>>>
> >> the
> >>
> >>>> code :) Nevertheless I must say I'd be happier if it would work at
> all
> >>>>
> >> in
> >>
> >>>> my system! (please see below)
> >>>>
> >>>>
> >>>>>
> >>>>>> Joel Sherrill wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> OK.. runs for me with the CVS head.
> >>>>>>>
> >>>>>>> You forget to include <rtems/confdefs.h> at the bottom after
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>> CONFIGURE_INIT.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> You're right in pointing this, it was actually an unfortunate
> typo...
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>> :) I expected as much. :)
> >>>>
> >>>>
> >>>>>>> And delete the timer configuration.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>> Done already! So a conclusion is still open for me, the code is ok,
> >>>>>
> >>>>>
> >>>> configuration is (now) ok, but instead of the current 4.8.1, I should
> >>>>
> >> try
> >>
> >>>> it with the CVS head (4.9.99?)
> >>>>
> >>>>
> >>>> How are you running it?
> >>>>
> >>>>
> >>>>> Thanks again for your help,
> >>>>>
> >>>>> Sérgio
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>>> Folks .. please consider support agreements. :-D
> >>>>>>> --joel
> >>>>>>>
> >>>>>>> Sérgio Santos wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>> Hello all,
> >>>>>>>>
> >>>>>>>> I'm using rtems 4.8.1, target is i386 (single core, with FC9),
> >>>>>>>>
> >> using
> >>
> >>>>>>>>
> >>>>>> bsp's between pc386 and pc686 and the RTEMS makefile templates.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>> I have been trying to port a Linux based application to RTEMS and
> >>>>>>>>
> >>>>>>>>
> >>>> found
> >>>>
> >>>>
> >>>>>> at some point I couldn't get POSIX signal handlers (set with
> >>>>>>
> >> sigaction)
> >>
> >>>> to
> >>>>
> >>>>
> >>>>>> ever execute. From what I've read in rtems-users and user docs, no
> >>>>>> problems should arise from using POSIX asynchronous signal handling
> >>>>>>
> >> in
> >>
> >>>>>> RTEMS, so my guess is I'm making some naïve mistake on code or
> >>>>>> configuration...
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>> Also, searching on the list, came across a similar problem, but
> >>>>>>>>
> >> this
> >>
> >>>>>>>>
> >>>>>> was a unique case and a long while ago:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>> http://www.rtems.com/ml/rtems-users/2002/september/msg00015.html
> >>>>>>>> Unfortunately that thread was not conclusive.
> >>>>>>>>
> >>>>>>>> After a few other tests I've got down to a simple test
> application
> >>>>>>>>
> >>>>>>>>
> >>>> (see
> >>>>
> >>>>
> >>>>>> below), similar to the code in the post I mentioned above: a thread
> >>>>>>
> >>>>>>
> >>>> sets
> >>>>
> >>>>
> >>>>>> sigaction and just does alarm(1), sleep(3) in a cycle. Alike the
> >>>>>>
> >> other
> >>
> >>>>>> tests, in RTEMS the handler never gets to run (although the signal
> >>>>>> (SIGALRM) is seen pending); in Linux all tests will work.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>> POSIX was enabled in the build configuration:
> >>>>>>>> ../../../rtems-4.8.1/c/configure --prefix=/opt/rtems-4.8 --
> >>>>>>>>
> >> host=i386-
> >>
> >>>>>>>>
> >>>>>> rtems4.8 --build=i686-pc-linux-gnu --target=i386-rtems4.8 --enable-
> >>>>>>
> >>>>>>
> >>>> posix -
> >>>>
> >>>>
> >>>>>> -disable-itron --enable-networking --enable-cxx --enable-rtems-
> debug
> >>>>>>
> >> --
> >>
> >>>>>> enable-rdbg --enable-rtemsbsp=pc386 --with-target-subdir=i386-
> >>>>>>
> >> rtems4.8
> >>
> >>>> --
> >>>>
> >>>>
> >>>>>> exec-prefix=/opt/rtems-4.8/i386-rtems4.8 --includedir=/opt/rtems-
> >>>>>>
> >>>>>>
> >>>> 4.8/i386-
> >>>>
> >>>>
> >>>>>> rtems4.8/include --cache-file=/dev/null --srcdir=../../../rtems-
> >>>>>>
> >> 4.8.1/c
> >>
> >>>>>>
> >>>>>>>> I post below the src for the simple test, having the RTEMS
> >>>>>>>>
> >>>>>>>>
> >>>> definitions
> >>>>
> >>>>
> >>>>>> in the end.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>> Thanks in advance for your help!
> >>>>>>>>
> >>>>>>>> Sérgio Santos
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> --------------
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> #include <signal.h>
> >>>>>>>> #include <stdio.h>
> >>>>>>>> #include <unistd.h>
> >>>>>>>> #include <stdlib.h>
> >>>>>>>>
> >>>>>>>> #include <bsp.h>
> >>>>>>>>
> >>>>>>>> void sig_handler(int sig){
> >>>>>>>> switch(sig){
> >>>>>>>> case SIGALRM:
> >>>>>>>> printf("HANDLER: caught SIGALRM\n");
> >>>>>>>> break;
> >>>>>>>> default:
> >>>>>>>> printf("Received unexpected signal (%d)\nBye!", sig);
> >>>>>>>> exit(1);
> >>>>>>>> }
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> void sig_init(){
> >>>>>>>>
> >>>>>>>> int rc;
> >>>>>>>> sigset_t sigset;
> >>>>>>>> struct sigaction sigact;
> >>>>>>>>
> >>>>>>>> rc = sigemptyset(&sigset);
> >>>>>>>> if (rc != 0) {
> >>>>>>>> printf("Can't empty set\n");exit(1);
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> sigact.sa_mask = sigset;
> >>>>>>>> sigact.sa_flags = 0;
> >>>>>>>> sigact.sa_handler = &sig_handler;
> >>>>>>>>
> >>>>>>>> rc = sigaction(SIGALRM, &sigact, NULL);
> >>>>>>>> if (rc != 0) {
> >>>>>>>> printf("Can't install handler\n"); exit(1);
> >>>>>>>> }
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> void *POSIX_Init(void *arg){
> >>>>>>>>
> >>>>>>>> int rc = 0;
> >>>>>>>> sigset_t pendingset;
> >>>>>>>>
> >>>>>>>> sig_init();
> >>>>>>>>
> >>>>>>>> rc = sigemptyset(&pendingset);
> >>>>>>>> if (rc != 0) {
> >>>>>>>> printf("Can't empty set\n");exit(1);
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> while(1){
> >>>>>>>> alarm(1);
> >>>>>>>> sleep(3);
> >>>>>>>> sigpending(&pendingset);
> >>>>>>>> printf("%s\n\n", ( sigismember(&pendingset, SIGALRM) ?
> >>>>>>>> "SIGALRM is pending" : "SIGALRM not pending"
> >>>>>>>>
> >> ));
> >>
> >>>>>>>> }
> >>>>>>>> return 0;
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> #define CONFIGURE_MAXIMUM_POSIX_THREADS 10
> >>>>>>>> #define CONFIGURE_MAXIMUM_POSIX_MUTEXES 10
> >>>>>>>> #define CONFIGURE_MAXIMUM_POSIX_TIMERS 10
> >>>>>>>> #define CONFIGURE_MAXIMUM_POSIX_QUEUED_SIGNALS 40
> >>>>>>>>
> >>>>>>>> #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
> >>>>>>>> #define CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER
> >>>>>>>> #define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
> >>>>>>>> #define CONFIGURE_POSIX_INIT_THREAD_TABLE
> >>>>>>>> #define CONFIGURE_INIT
> >>>>>>>>
> >>>>>>>> // EOF
> >>>>>>>> ----
> >>>>>>>>
> >>>>>>>> _______________________________________________
> >>>>>>>> rtems-users mailing list
> >>>>>>>> rtems-users at rtems.com
> >>>>>>>> http://rtems.rtems.org/mailman/listinfo/rtems-users
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>> --
> >>>>>> Joel Sherrill, Ph.D. Director of Research & Development
> >>>>>> joel.sherrill at OARcorp.com On-Line Applications Research
> >>>>>> Ask me about RTEMS: a free RTOS Huntsville AL 35805
> >>>>>> Support Available (256) 722-9985
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>> --
> >>>> Joel Sherrill, Ph.D. Director of Research & Development
> >>>> joel.sherrill at OARcorp.com On-Line Applications Research
> >>>> Ask me about RTEMS: a free RTOS Huntsville AL 35805
> >>>> Support Available (256) 722-9985
> >>>>
> >>>>
> >>>>
> >>>
> >> --
> >> Joel Sherrill, Ph.D. Director of Research & Development
> >> joel.sherrill at OARcorp.com On-Line Applications Research
> >> Ask me about RTEMS: a free RTOS Huntsville AL 35805
> >> Support Available (256) 722-9985
> >>
> >>
> >
> >
>
>
> --
> Joel Sherrill, Ph.D. Director of Research & Development
> joel.sherrill at OARcorp.com On-Line Applications Research
> Ask me about RTEMS: a free RTOS Huntsville AL 35805
> Support Available (256) 722-9985
>
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