1 files changed, 54 insertions, 0 deletions
diff --git a/libddekit/lock.c b/libddekit/lock.c
new file mode 100644
index 00000000..e534bebe
--- /dev/null
+++ b/libddekit/lock.c
@@ -0,0 +1,54 @@
+#include <cthreads.h>
+
+#include "ddekit/lock.h"
+#include "ddekit/memory.h"
+
+#define DDEKIT_DEBUG_LOCKS 0
+
+struct ddekit_lock {
+	struct mutex lock;
+	cthread_t helder;
+};
+
+void _ddekit_lock_init(struct ddekit_lock **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) {
+	mutex_free (*mtx);
+	*mtx = NULL;
+}
+
+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) {
+	if (mutex_try_lock (&(*mtx)->lock)) { /* lock succeessfully */
+		(*mtx)->helder = cthread_self ();
+		return 0;
+	}
+	return -1;
+}
+
+void _ddekit_lock_unlock(struct ddekit_lock **mtx) {
+	// TODO I wonder if it can cause any trouble.
+	(*mtx)->helder = NULL;
+	mutex_unlock (&(*mtx)->lock);
+}
+
+
+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)->helder;
+}
+