undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/util/concurrent/locks/Lock/Mutex.java

@@ -0,0 +1,83 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.AbstractQueuedSynchronizer;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+
+/**
+ * A sample user extension of AbstractQueuedSynchronizer.
+ */
+public class Mutex implements Lock, java.io.Serializable {
+    private static class Sync extends AbstractQueuedSynchronizer {
+        public boolean isHeldExclusively() { return getState() == 1; }
+
+        public boolean tryAcquire(int acquires) {
+            assert acquires == 1; // Does not use multiple acquires
+            return compareAndSetState(0, 1);
+        }
+
+        public boolean tryRelease(int releases) {
+            setState(0);
+            return true;
+        }
+
+        Condition newCondition() { return new ConditionObject(); }
+
+        private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
+            s.defaultReadObject();
+            setState(0); // reset to unlocked state
+        }
+    }
+
+    private final Sync sync = new Sync();
+    public void lock() {
+        sync.acquire(1);
+    }
+    public boolean tryLock() {
+        return sync.tryAcquire(1);
+    }
+    public void lockInterruptibly() throws InterruptedException {
+        sync.acquireInterruptibly(1);
+    }
+    public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException {
+        return sync.tryAcquireNanos(1, unit.toNanos(timeout));
+    }
+    public void unlock() { sync.release(1); }
+    public Condition newCondition() { return sync.newCondition(); }
+    public boolean isLocked() { return sync.isHeldExclusively(); }
+    public boolean hasQueuedThreads() { return sync.hasQueuedThreads(); }
+}