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

[chenguanxi11234@163.com]

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            | 41 ++++++++++++++-----
 1 file changed, 30 insertions(+), 11 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..3082140e3 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 +10,24 @@
  * will unlock the semaphore from another process.
  */
 
+/* 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.
+ */
 
+#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);
+
+	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