Record the thread who holds the lock by ourselves.

cthreads mutex might contain the holder only when WAITDEBUG is defined.
I think it's better to implement it by ourselves.

1 files changed, 16 insertions, 4 deletions

diff --git a/libddekit/lock.c b/libddekit/lock.c
index f64d571b..bf643e65 100644
--- a/libddekit/lock.c
+++ b/libddekit/lock.c
@@ -6,11 +6,16 @@
 
 struct ddekit_lock {
 	struct mutex lock;
+	cthread_t helder;
 };
 
 void _ddekit_lock_init(struct ddekit_lock **mtx) {
-	*mtx = (struct ddekit_lock *) mutex_alloc ();
-	mutex_init (*mtx);
+	struct ddekit_lock *lock;
+
+	lock = (struct ddekit_lock *) ddekit_simple_malloc (sizeof *lock);
+	mutex_init (&lock->lock);
+	lock->helder = NULL;
+	*mtx = lock;
 }
 
 void _ddekit_lock_deinit(struct ddekit_lock **mtx) {
@@ -20,15 +25,22 @@ void _ddekit_lock_deinit(struct ddekit_lock **mtx) {
 
 void _ddekit_lock_lock(struct ddekit_lock **mtx) {
 	mutex_lock (&(*mtx)->lock);
+	(*mtx)->helder = cthread_self ();
 }
 
 /* returns 0 on success, != 0 if it would block */
 int _ddekit_lock_try_lock(struct ddekit_lock **mtx) {
-	return !mutex_try_lock (&(*mtx)->lock);
+	if (mutex_try_lock (&(*mtx)->lock)) { /* lock succeessfully */
+		(*mtx)->helder = cthread_self ();
+		return 0;
+	}
+	return -1;
 }
 
 void _ddekit_lock_unlock(struct ddekit_lock **mtx) {
 	mutex_unlock (&(*mtx)->lock);
+	// TODO I wonder if it can cause any trouble.
+	(*mtx)->helder = NULL;
 }
 
 
@@ -36,6 +48,6 @@ int _ddekit_lock_owner(struct ddekit_lock **mtx) {
 	/* The return value is the address of the holder.
 	 * I hope it will be OK. At least, it is OK
 	 * for the current implementation of DDE Linux/BSD */
-	return (int) (*mtx)->lock.holder;
+	return (int) (*mtx)->holder;
 }