From 4b3c07027521711722b825dc293f44a57f7a8648 Mon Sep 17 00:00:00 2001
From: stefan <stefan@315a16e6-25f9-4109-90ae-ca3045a26c18>
Date: Tue, 3 Aug 2010 07:12:27 +0000
Subject: [PATCH] - add some additional error checks

git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@19 315a16e6-25f9-4109-90ae-ca3045a26c18
---
 include/metalsvm/semaphore.h | 38 +++++++++++++++++++++++++++++++++---
 1 file changed, 35 insertions(+), 3 deletions(-)

diff --git a/include/metalsvm/semaphore.h b/include/metalsvm/semaphore.h
index 9d7750a1..6d2fb7c8 100644
--- a/include/metalsvm/semaphore.h
+++ b/include/metalsvm/semaphore.h
@@ -35,21 +35,34 @@ typedef struct {
 	spinlock_t lock;
 } sem_t;
 
-inline static void sem_init(sem_t* s, unsigned int v) {
+inline static int sem_init(sem_t* s, unsigned int v) {
 	unsigned int i;
 
+	if (BUILTIN_EXPECT(!s, 0))
+		return -1;
+
 	s->value = v;
 	s->pos = 0;
 	for(i=0; i<MAX_TASKS; i++)
 		s->queue[i] = MAX_TASKS;
 	spinlock_init(&s->lock);
+
+	return 0;
 }
 
-inline static void sem_destroy(sem_t* s) {
+inline static int sem_destroy(sem_t* s) {
+	if (BUILTIN_EXPECT(!s, 0))
+		return -1;
+
 	spinlock_destroy(&s->lock);
+
+	return 0;
 }
 
 inline static int sem_wait(sem_t* s) {
+	if (BUILTIN_EXPECT(!s, 0))
+		return -1;
+
 next_try:
         spinlock_lock(&s->lock);
 	if (s->value > 0) {
@@ -67,7 +80,26 @@ next_try:
 	return 0;
 }
 
+inline static int sem_trywait(sem_t* s) {
+	int ret = -1;
+
+	if (BUILTIN_EXPECT(!s, 0))
+		return -1;
+
+	spinlock_lock(&s->lock);
+	if (s->value > 0) {
+		s->value--;
+		ret = 0;
+	}
+	spinlock_unlock(&s->lock);
+
+	return ret;
+}
+
 inline static int sem_post(sem_t* s) {
+	if (BUILTIN_EXPECT(!s, 0))
+		return -1;
+
 	spinlock_lock(&s->lock);
 	if (s->value > 0) {
 		s->value++;
@@ -75,8 +107,8 @@ inline static int sem_post(sem_t* s) {
 	} else {
 		unsigned int k, i;
 
-		i = s->pos;
 		s->value++;
+		i = s->pos;
 		for(k=0; k<MAX_TASKS; k++) {
 			if (s->queue[i] < MAX_TASKS) {
 				wakeup_task(s->queue[i]);