--- Libc/Libc-1353.100.2/sys/OSMemoryNotification.c
+++ Libc/Libc-583/sys/OSMemoryNotification.c
@@ -21,11 +21,123 @@
  * @APPLE_LICENSE_HEADER_END@
  */
 
-// Legacy symbols preserved for binary compatibility.
+#include <errno.h>
+#include <libkern/OSMemoryNotification.h>
+#include <mach/mach.h>
+#include <notify.h>
+#include <stdlib.h>
+#include <sys/time.h>
 
 const char *kOSMemoryNotificationName = "com.apple.system.memorystatus";
 
-int OSMemoryNotificationCurrentLevel(void)
+struct _OSMemoryNotification {
+	int token;
+	mach_port_t port;
+};
+
+int
+OSMemoryNotificationCreate(OSMemoryNotificationRef *note)
 {
-	return 0; // OSMemoryNotificationLevelNormal
+	OSMemoryNotificationRef ref = malloc(sizeof(struct _OSMemoryNotification));
+
+	if (NULL == ref) {
+		return ENOMEM;
+	}
+	
+	if (NOTIFY_STATUS_OK != notify_register_mach_port(kOSMemoryNotificationName, &ref->port, 0, &ref->token))
+		return ENOMEM;
+
+	*note = ref;
+
+	return 0;
 }
+
+int
+OSMemoryNotificationDestroy(OSMemoryNotificationRef note)
+{
+	if (NOTIFY_STATUS_OK != notify_cancel(note->token))
+		return EINVAL;
+
+	if (KERN_SUCCESS != mach_port_deallocate(mach_task_self(), note->port))
+		return EINVAL;
+
+	free(note);
+
+	return 0;
+}
+		
+int
+OSMemoryNotificationWait(OSMemoryNotificationRef note, OSMemoryNotificationLevel *level)
+{
+
+	return OSMemoryNotificationTimedWait(note, level, NULL);
+}
+
+static mach_msg_timeout_t
+abs_to_timeout(const struct timeval *abstime)
+{
+	struct timeval rel, now;
+
+	gettimeofday(&now, NULL);
+
+	rel.tv_usec = abstime->tv_usec - now.tv_usec;
+	rel.tv_sec = abstime->tv_sec - now.tv_sec;
+	if (rel.tv_usec < 0) {
+		rel.tv_usec += 1000000;
+		rel.tv_sec--;
+	}
+	if (((int)rel.tv_sec < 0) || ((rel.tv_sec == 0) && (rel.tv_usec == 0))) {
+		return 0;
+	}
+	return rel.tv_sec * 1000 + rel.tv_usec / 1000;
+}
+
+int
+OSMemoryNotificationTimedWait(OSMemoryNotificationRef note, OSMemoryNotificationLevel *level, const struct timeval *abstime)
+{
+	mach_msg_empty_rcv_t msg = {{0}};
+	mach_msg_return_t ret;
+	uint64_t val;
+
+	if (abstime) {
+		mach_msg_timeout_t timeout = abs_to_timeout(abstime);
+
+		if (0 == timeout)
+			return ETIMEDOUT;
+
+		ret = mach_msg(&msg.header, MACH_RCV_MSG | MACH_RCV_TIMEOUT, 0, sizeof msg, note->port, timeout, MACH_PORT_NULL);
+
+		if (MACH_RCV_TIMED_OUT == ret) {
+			return ETIMEDOUT;
+		} 
+	} else {
+		ret = mach_msg(&msg.header, MACH_RCV_MSG, 0, sizeof msg, note->port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
+	}
+
+	if (MACH_MSG_SUCCESS != ret)
+		return EINVAL;
+
+	if (NOTIFY_STATUS_OK != notify_get_state(note->token, &val))
+		return EINVAL;
+
+	*level = (OSMemoryNotificationLevel)val;
+
+	return 0;
+}
+
+OSMemoryNotificationLevel OSMemoryNotificationCurrentLevel(void)
+{
+	uint64_t val;
+	int token;
+
+	if (NOTIFY_STATUS_OK != notify_register_check(kOSMemoryNotificationName, &token))
+		return OSMemoryNotificationLevelAny;
+
+	if (NOTIFY_STATUS_OK != notify_get_state(token, &val))
+		return OSMemoryNotificationLevelAny;
+
+	if (NOTIFY_STATUS_OK != notify_cancel(token))
+		return OSMemoryNotificationLevelAny;
+
+	return (OSMemoryNotificationLevel)val;
+}