posix: pthread: implement non-standard try-join and timed-join

These functions can be used to join pthreads in a non-standard way.
The function pthread_tryjoin will not block and simply test whether the
thread has exited already. The function pthread_timed_join will only block
until the specified time. The functions are wrappers for calling the
k_thread_join with timeout K_NO_WAIT and with a specific timeout as opposed
to calling it with K_FOREVER.

Signed-off-by: Cla Galliard <[email protected]>

Author: ClaCodes

include/zephyr/posix/pthread.h

@@ -429,6 +429,8 @@ int pthread_attr_setinheritsched(pthread_attr_t *attr, int inheritsched);
 int pthread_once(pthread_once_t *once, void (*initFunc)(void));
 #endif
 FUNC_NORETURN void pthread_exit(void *retval);
+int pthread_timedjoin_np(pthread_t thread, void **status, const struct timespec *abstime);
+int pthread_tryjoin_np(pthread_t thread, void **status);
 int pthread_join(pthread_t thread, void **status);
 int pthread_cancel(pthread_t pthread);
 int pthread_detach(pthread_t thread);

lib/posix/options/pthread.c

@@ -81,6 +81,7 @@ BUILD_ASSERT((PTHREAD_CANCEL_ENABLE == 0 || PTHREAD_CANCEL_DISABLE == 0) &&
 BUILD_ASSERT(CONFIG_POSIX_PTHREAD_ATTR_STACKSIZE_BITS + CONFIG_POSIX_PTHREAD_ATTR_GUARDSIZE_BITS <=
 	     32);
 
+int64_t timespec_to_timeoutms(const struct timespec *abstime);
 static void posix_thread_recycle(void);
 static sys_dlist_t posix_thread_q[] = {
 	SYS_DLIST_STATIC_INIT(&posix_thread_q[POSIX_THREAD_READY_Q]),
@@ -1061,12 +1062,7 @@ void pthread_exit(void *retval)
 	CODE_UNREACHABLE;
 }
 
-/**
- * @brief Wait for a thread termination.
- *
- * See IEEE 1003.1
- */
-int pthread_join(pthread_t pthread, void **status)
+static int pthread_timedjoin_internal(pthread_t pthread, void **status, k_timeout_t timeout)
 {
 	int ret = ESRCH;
 	struct posix_thread *t = NULL;
@@ -1115,8 +1111,19 @@ int pthread_join(pthread_t pthread, void **status)
 		break;
 	}
 
-	ret = k_thread_join(&t->thread, K_FOREVER);
-	/* other possibilities? */
+	ret = k_thread_join(&t->thread, timeout);
+	if (ret != 0) {
+		/* when joining failed, ensure that the thread can be joined later */
+		SYS_SEM_LOCK(&pthread_pool_lock) {
+			t->attr.detachstate = PTHREAD_CREATE_JOINABLE;
+		}
+	}
+	if (ret == -EBUSY) {
+		return EBUSY;
+	} else if (ret == -EAGAIN) {
+		return ETIMEDOUT;
+	}
+	/* Can only be ok or -EDEADLK, which should never occur for pthreads */
 	__ASSERT_NO_MSG(ret == 0);
 
 	LOG_DBG("Joined pthread %p", &t->thread);
@@ -1131,6 +1138,44 @@ int pthread_join(pthread_t pthread, void **status)
 	return 0;
 }
 
+/**
+ * @brief Await a thread termination with timeout.
+ *
+ * Non-portable GNU extension of IEEE 1003.1
+ */
+int pthread_timedjoin_np(pthread_t pthread, void **status, const struct timespec *abstime)
+{
+	if (abstime == NULL) {
+		return EINVAL;
+	}
+
+	if (abstime->tv_sec < 0 || abstime->tv_nsec < 0 || abstime->tv_nsec >= NSEC_PER_SEC) {
+		return EINVAL;
+	}
+
+	return pthread_timedjoin_internal(pthread, status, K_MSEC(timespec_to_timeoutms(abstime)));
+}
+
+/**
+ * @brief Check a thread for termination.
+ *
+ * Non-portable GNU extension of IEEE 1003.1
+ */
+int pthread_tryjoin_np(pthread_t pthread, void **status)
+{
+	return pthread_timedjoin_internal(pthread, status, K_NO_WAIT);
+}
+
+/**
+ * @brief Await a thread termination.
+ *
+ * See IEEE 1003.1
+ */
+int pthread_join(pthread_t pthread, void **status)
+{
+	return pthread_timedjoin_internal(pthread, status, K_FOREVER);
+}
+
 /**
  * @brief Detach a thread.
  *