lib: posix: mutex: implement pthread_mutexattr_setprotocol

Implement and test `pthread_mutexattr_setprotocol()`.

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

Author: ycsin

include/zephyr/posix/pthread.h

@@ -183,6 +183,8 @@ int pthread_condattr_setclock(pthread_condattr_t *att, clockid_t clock_id);
  *  FIXME: Only PRIO_NONE is supported. Implement other protocols.
  */
 #define PTHREAD_PRIO_NONE           0
+#define PTHREAD_PRIO_INHERIT        1
+#define PTHREAD_PRIO_PROTECT        2
 
 /**
  * @brief POSIX threading compatibility API

lib/posix/options/mutex.c

@@ -315,6 +315,29 @@ int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
 	return 0;
 }
 
+/**
+ * @brief Set protocol attribute for mutex.
+ *
+ * See IEEE 1003.1
+ */
+int pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr, int protocol)
+{
+	if (attr == NULL) {
+		return EINVAL;
+	}
+
+	switch (protocol) {
+	case PTHREAD_PRIO_NONE:
+		return 0;
+	case PTHREAD_PRIO_INHERIT:
+		return ENOTSUP;
+	case PTHREAD_PRIO_PROTECT:
+		return ENOTSUP;
+	default:
+		return EINVAL;
+	}
+}
+
 int pthread_mutexattr_init(pthread_mutexattr_t *attr)
 {
 	struct pthread_mutexattr *const a = (struct pthread_mutexattr *)attr;

tests/posix/common/src/mutex.c

@@ -63,6 +63,10 @@ static void test_mutex_common(int type, void *(*entry)(void *arg))
 	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_not_ok(pthread_mutexattr_setprotocol(&mut_attr, PTHREAD_PRIO_INHERIT));
+	zassert_not_ok(pthread_mutexattr_setprotocol(&mut_attr, PTHREAD_PRIO_PROTECT));
+	zassert_ok(pthread_mutexattr_setprotocol(&mut_attr, PTHREAD_PRIO_NONE));
 	zassert_ok(pthread_mutexattr_getprotocol(&mut_attr, &protocol),
 		   "reading mutex protocol is failed");
 	zassert_ok(pthread_mutexattr_destroy(&mut_attr));

tests/posix/headers/src/pthread_h.c

@@ -128,7 +128,7 @@ ZTEST(posix_headers, test_pthread_h)
 	zassert_not_null(pthread_mutexattr_gettype);
 	zassert_not_null(pthread_mutexattr_init);
 	/* zassert_not_null(pthread_mutexattr_setprioceiling); */ /* not implemented */
-	/* zassert_not_null(pthread_mutexattr_setprotocol); */    /* not implemented */
+	zassert_not_null(pthread_mutexattr_setprotocol);
 	/* zassert_not_null(pthread_mutexattr_setpshared); */     /* not implemented */
 	/* zassert_not_null(pthread_mutexattr_setrobust); */      /* not implemented */
 	zassert_not_null(pthread_mutexattr_settype);