kernel: POSIX: Fixing return value of POSIX APIs on error.

As per IEEE 1003.1 POSIX APIs should return ERROR_CODE on error.
But currently these are returning -ERROR_CODE instead of ERROR_CODE.
So fixing the return value.

Signed-off-by: Youvedeep Singh <[email protected]>

Author: youvedeep-singh

include/posix/pthread.h

@@ -193,7 +193,7 @@ static inline int pthread_mutex_timedlock(pthread_mutex_t *m,
 {
 	int ret = k_sem_take(m->sem, _ts_to_ms(to));
 
-	return ret == -EAGAIN ? -ETIMEDOUT : ret;
+	return ret == 0 ? ret : ETIMEDOUT;
 }
 
 /**

kernel/posix/pthread_cond.c

@@ -34,7 +34,7 @@ static int cond_wait(pthread_cond_t *cv, pthread_mutex_t *mut, int timeout)
 	 */
 	pthread_mutex_lock(mut);
 
-	return ret == -EAGAIN ? -ETIMEDOUT : ret;
+	return ret == -EAGAIN ? ETIMEDOUT : ret;
 }
 
 /* This implements a "fair" scheduling policy: at the end of a POSIX

kernel/posix/pthread_mutex.c

@@ -11,7 +11,7 @@
 
 int pthread_mutex_trylock(pthread_mutex_t *m)
 {
-	int key = irq_lock(), ret = -EBUSY;
+	int key = irq_lock(), ret = EBUSY;
 
 	if (m->sem->count) {
 		m->sem->count = 0;