lib: posix: mutex: check args of pthread_mutexattr_getprotocol

Perform arguments checking in the
`pthread_mutexattr_getprotocol()` function.

Signed-off-by: Yong Cong Sin <[email protected]>

Author: ycsin

lib/posix/options/mutex.c

@@ -307,6 +307,10 @@ int pthread_mutex_destroy(pthread_mutex_t *mu)
 int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
 				  int *protocol)
 {
+	if ((attr == NULL) || (protocol == NULL)) {
+		return EINVAL;
+	}
+
 	*protocol = PTHREAD_PRIO_NONE;
 	return 0;
 }

tests/posix/common/src/mutex.c

@@ -60,6 +60,9 @@ static void test_mutex_common(int type, void *(*entry)(void *arg))
 
 	zassert_ok(pthread_mutexattr_gettype(&mut_attr, &actual_type),
 		   "reading mutex type is failed");
+	zassert_not_ok(pthread_mutexattr_getprotocol(NULL, &protocol));
+	zassert_not_ok(pthread_mutexattr_getprotocol(&mut_attr, NULL));
+	zassert_not_ok(pthread_mutexattr_getprotocol(NULL, NULL));
 	zassert_ok(pthread_mutexattr_getprotocol(&mut_attr, &protocol),
 		   "reading mutex protocol is failed");
 	zassert_ok(pthread_mutexattr_destroy(&mut_attr));