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diff --git a/ext/tap-mac/tuntap/src/lock.h b/ext/tap-mac/tuntap/src/lock.h
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+++ b/ext/tap-mac/tuntap/src/lock.h
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+/*
+ * ip tunnel/ethertap device for MacOSX.
+ *
+ * Locking is not as straightforward for Tiger. So declare our own locking class.
+ */
+/*
+ * Copyright (c) 2011 Mattias Nissler <mattias.nissler@gmx.de>
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are permitted
+ * provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice, this list of
+ *      conditions and the following disclaimer.
+ *   2. Redistributions in binary form must reproduce the above copyright notice, this list of
+ *      conditions and the following disclaimer in the documentation and/or other materials provided
+ *      with the distribution.
+ *   3. The name of the author may not be used to endorse or promote products derived from this
+ *      software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __LOCK_H__
+#define __LOCK_H__
+
+extern "C" {
+
+#include <kern/locks.h>
+#include <sys/param.h>
+
+}
+
+/* our own locking class. declares the common interface of the locking primitives. */
+class tt_lock {
+	
+	protected:
+		/* locking group */
+		static lck_grp_t *tt_lck_grp;
+
+	public:
+		/* be virtual */
+		virtual ~tt_lock() { };
+
+		/* static intialization (inits the locking group) */
+		static bool initialize();
+		static void shutdown();
+
+		/* locking */
+		virtual void lock() = 0;
+		virtual void unlock() = 0;
+
+		/* monitor primitives */
+		virtual void sleep(void* cond) = 0;
+		virtual void sleep(void* cond, uint64_t) = 0;
+		virtual void wakeup(void* cond) = 0;
+};
+
+/* simple mutex */
+class tt_mutex : public tt_lock {
+
+	private:
+		/* underlying darwin lock */
+		lck_rw_t *lck;
+
+	public:
+		tt_mutex();
+		virtual ~tt_mutex();
+
+		void lock();
+		void unlock();
+
+		/* monitor primitives */
+		void sleep(void* cond);
+		void sleep(void* cond, uint64_t);
+		void wakeup(void* cond);
+};
+
+/* A very special locking class that we use to track threads that enter and leave the character
+ * device service functions. They call enter() before entering the actual service routinge and
+ * exit() when done. enter() only permits them to pass when the gate isn't locked. Furthermore, the
+ * gate assigns ticket numbers to everyone that passes the gate, so you can check whether more
+ * threads came through. See tuntap_mgr::shutdown() for how we use that stuff.
+ */
+class tt_gate : public tt_lock {
+
+	private:
+		/* synchronization lock */
+		tt_mutex slock;
+		/* ticket number */
+		unsigned int ticket_number;
+		/* count of threads that are in */
+		unsigned int population;
+
+	public:
+		/* construct a new gate */
+		tt_gate();
+
+		/* enter - pass the gate */
+		void enter();
+		/* exit - pass the gate */
+		void exit();
+
+		/* check whether anyone is in */
+		bool is_anyone_in();
+		/* gets the next ticket number */
+		unsigned int get_ticket_number();
+
+		/* lock the gate */
+		void lock();
+		/* unlock the gate */
+		void unlock();
+
+		/* monitor primitives */
+		void sleep(void* cond);
+		void sleep(void* cond, uint64_t);
+		void wakeup(void* cond);
+};
+
+/* auto_lock and auto_rwlock serve as automatic lock managers: Create an object, passing the
+ * tt_[rw]lock you want to lock to have it grab the lock. When the object goes out of scope, the
+ * destructor of the class will release the lock.
+ */
+class auto_lock {
+
+	protected:
+		/* the lock we hold */
+		tt_lock *l;
+
+	public:
+		auto_lock(tt_lock *m)
+			: l(m)
+		{
+			lock();
+		}
+
+		~auto_lock()
+		{
+			unlock();
+		}
+
+		void lock()
+		{
+			l->lock();
+		}
+
+		void unlock()
+		{
+			l->unlock();
+		}
+};
+
+#endif /* __LOCK_H__ */
+