[LTP] [PATCH v2] posix/conformance/interfaces/sem_timedwait/2-1: Fix test

[LTP] [PATCH v2] posix/conformance/interfaces/sem_timedwait/2-1: Fix test

[chenguanxi11234]

From: Chen Haonan <chen.haonan2@zte.com.cn>

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.

Signed-off-by: Chen Haonan <chen.haonan2@zte.com.cn>
---
 .../interfaces/sem_timedwait/2-1.c            | 34 ++++++++++++-------
 1 file changed, 22 insertions(+), 12 deletions(-)
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/sem_timedwait/2-1.c b/testcases/open_posix_testsuite/conformance/interfaces/sem_timedwait/2-1.c
index 655e35108..f5b9cf921 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/sem_timedwait/2-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/sem_timedwait/2-1.c
@@ -10,13 +10,14 @@
  * will unlock the semaphore from another process.
  */
 
-
+#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 +29,17 @@
 
 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);
+
+	if (sem_init(mysemp, 1, 0) == -1) {
 		perror(ERROR_PREFIX "sem_init");
 		return PTS_UNRESOLVED;
 	}
@@ -43,20 +49,22 @@ 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 +72,14 @@ 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


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Re: [LTP] [PATCH v2] posix/conformance/interfaces/sem_timedwait/2-1: Fix test

[Cyril Hrubis]

Hi!
> -	/* 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);

Again, this can be just anonymous memory, need need to back it up by the
file descriptor. Should be as easy as:

	mysemp = mmap(NULL, sizeof(*mysemp), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);

As well as the error conditions are still not checked.

-- 
Cyril Hrubis
chrubis@suse.cz

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