POSIX signal handling

[Joel Sherrill]

Sergios,

I meant to ask.. Is it ok to include this in the RTEMS examples
as a simple example of alarm and signals?

--joel

Joel Sherrill wrote:
> OK.. runs for me with the CVS head.
>
> You forget to include <rtems/confdefs.h> at the bottom after CONFIGURE_INIT.
> And delete the timer configuration.
>
> 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
>> ----
>>
>> _______________________________________________
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>> 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
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