Re: [LTP] [PATCH] posix/conformance/interfaces/sem_timedwait/2-1: Fix test

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> +/* Modifications by: Chen Haonan <chen.haonan2@zte.com.cn>
> + * Date: 2024-01-08
> + *
> + * Since the parent and child processes are not operating on
> + * the same semaphore, this code wasn't doing its job correctly
> + * before, so we mapped the semaphore to a piece of shared
> + * memory and changed some implementation details in the
> + * original code to make it work.
> + */

Please do not duplicate the commit message in the actual code.

> +#include <stdlib.h>
>  #include <stdio.h>
>  #include <errno.h>
>  #include <unistd.h>
>  #include <semaphore.h>
>  #include <sys/stat.h>
>  #include <sys/wait.h>
> +#include <sys/mman.h>
>  #include <fcntl.h>
>  #include <signal.h>
>  #include <time.h>
> @@ -28,12 +39,16 @@
>  
>  int main(void)
>  {
> -	sem_t mysemp;
> +	sem_t *mysemp;
>  	struct timespec ts;
>  	int pid;
>  
> -	/* Semaphore started out locked */
> -	if (sem_init(&mysemp, 0, 0) == -1) {
> +	/* Map semaphore to shared memory */
> +	int shm_fd = shm_open("/myshm", O_CREAT | O_RDWR, 0666);
> _
> +	ftruncate(shm_fd, sizeof(sem_t));
> +	mysemp = (sem_t *)mmap(NULL, sizeof(sem_t), PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);

We do not have to have a shm object for a shared memory between a parent
and a child process, for that we can just map anonymous shared memory.

> +	if (sem_init(mysemp, 1, 0) == -1) {
>  		perror(ERROR_PREFIX "sem_init");
>  		return PTS_UNRESOLVED;
>  	}
> @@ -43,20 +58,22 @@ int main(void)
>  	{
>  		ts.tv_sec = time(NULL) + 2;
>  		ts.tv_nsec = 0;
> -
> -		if (sem_timedwait(&mysemp, &ts) == -1) {
> +		if (sem_timedwait(mysemp, &ts) == -1) {
>  			puts("TEST FAILED");
> +			sem_destroy(mysemp);
> +			munmap(mysemp, sizeof(sem_t));
> +			close(shm_fd);
> +			shm_unlink("/myshm");
>  			return PTS_FAIL;
>  		} else {
> -			puts("TEST PASSED");
> -			sem_destroy(&mysemp);
> +			puts("TEST PASSED");
>  			return PTS_PASS;
>  		}
>  	} else if (pid > 0)	// parent to unlock semaphore
>  	{
>  		int i;
>  		sleep(1);
> -		if (sem_post(&mysemp) == -1) {
> +		if (sem_post(mysemp) == -1) {
>  			perror(ERROR_PREFIX "sem_post");
>  			return PTS_FAIL;
>  		}
> @@ -64,12 +81,14 @@ int main(void)
>  			perror("Error waiting for child to exit");
>  			return PTS_UNRESOLVED;
>  		}
> -
> -		if (!WEXITSTATUS(i)) {
> +		if (WEXITSTATUS(i)) {
>  			return PTS_FAIL;
>  		}
>  		puts("TEST PASSED");
> -		sem_destroy(&mysemp);
> +		sem_destroy(mysemp);
> +		munmap(mysemp, sizeof(sem_t));
> +		close(shm_fd);
> +		shm_unlink("/myshm");
>  		return PTS_PASS;
>  	}
>  	return PTS_UNRESOLVED;
> -- 
> 2.25.1
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp