POSIX signal handling

[Sérgio Santos]

> -----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...

> > 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?)

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
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>