Re: [LTP] [PATCH v4 2/2] open_posix_testsuite/../mq_timedsend/12-1: fix race

[chrubis@suse.cz]

>  /*
>   * This handler is just used to catch the signal and stop sleep (so the
> @@ -59,12 +59,10 @@ int errno_eintr;
>   */
>  void justreturn_handler(int signo)
>  {
> -	/* Indicate that the signal handler was called */
> -	in_handler = 1;
> -	return;
> +	in_handler++;
>  }
>  
> -void *a_thread_func()
> +void *a_thread_func(void *arg)
>  {
>  	int i, ret;
>  	struct sigaction act;
> @@ -86,101 +84,111 @@ void *a_thread_func()
>  	attr.mq_maxmsg = MAXMSG;
>  	attr.mq_msgsize = BUFFER;
>  	gqueue = mq_open(gqname, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR, &attr);
> -	if (gqueue == (mqd_t) - 1) {
> -		perror("mq_open() did not return success");
> -		pthread_exit((void *)PTS_UNRESOLVED);
> -		return NULL;
> -	}
> +	if (gqueue == (mqd_t) -1)
> +		error_and_exit(errno, "mq_open");
>  
> -	/* mq_timedsend will block for 10 seconds when it waits */
> -	ts.tv_sec = time(NULL) + 10;
> +	/* mq_timedsend will block for TIMEOUT seconds when it waits */
> +	ts.tv_sec = time(NULL) + TIMEOUT;
>  	ts.tv_nsec = 0;
>  
> -	/* Tell main it can go ahead and start sending SIGUSR1 signal */
> -	sem = INMAIN;
> +	/* main can now start sending SIGUSR1 signal */
> +	ret = pthread_barrier_wait(&barrier);
> +	if (ret != 0 && ret != PTHREAD_BARRIER_SERIAL_THREAD)
> +		error_and_exit(ret, "pthread_barrier_wait start");
>  
>  	for (i = 0; i < MAXMSG + 1; i++) {
>  		ret = mq_timedsend(gqueue, msgptr, strlen(msgptr), 1, &ts);
> -		if (ret	!= -1)
> -			continue;
> -
> -		if (errno == EINTR) {
> -			if (mq_unlink(gqname) != 0) {
> -				perror("mq_unlink() did not return success");
> -				pthread_exit((void *)PTS_UNRESOLVED);
> -				return NULL;
> -			}
> -			printf("thread: mq_timedsend interrupted by signal"
> -				" and correctly set errno to EINTR\n");
> -			errno_eintr = 1;
> -			pthread_exit((void *)PTS_PASS);
> -			return NULL;
> -		} else {
> -			printf("mq_timedsend not interrupted by signal or"
> -				" set errno to incorrect code: %d\n", errno);
> -			pthread_exit((void *)PTS_FAIL);
> -			return NULL;
> +		if (ret == -1) {
> +			mq_timedsend_errno = errno;
> +			break;
>  		}
>  	}
>  
> -	/* Tell main that it the thread did not block like it should have */
> -	sem = INTHREAD;
> +	if (mq_unlink(gqname) != 0)
> +		error_and_exit(errno, "mq_unlink");
> +
> +	switch (mq_timedsend_errno) {
> +	case -1:
> +		mq_timedsend_errno = 0;
> +		printf("Error: mq_timedsend wasn't interrupted\n");
> +		break;
> +	case EINTR:
> +		printf("thread: mq_timedsend interrupted by signal"
> +			" and correctly set errno to EINTR\n");
> +		break;
> +	default:
> +		printf("mq_timedsend not interrupted by signal or"
> +			" set errno to incorrect code: %d\n",
> +			mq_timedsend_errno);
> +		break;
> +	}
> +
> +	/* wait until main stops sending signals */
> +	ret = pthread_barrier_wait(&barrier);
> +	if (ret != 0 && ret != PTHREAD_BARRIER_SERIAL_THREAD)
> +		error_and_exit(ret, "pthread_barrier_wait end");
>  
> -	perror("Error: thread never blocked\n");
> -	pthread_exit((void *)PTS_FAIL);
> -	return NULL;
> +	if (mq_timedsend_errno == EINTR)
> +		pthread_exit((void *)PTS_PASS);
> +	else
> +		pthread_exit((void *)PTS_FAIL);

Are these even used? The pthread_join() below has NULL parameter and the
mq_timedsend_errno is used directly.

The rests looks OK.

-- 
Cyril Hrubis
chrubis@suse.cz

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