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/nio/file/WatchService/DeleteInterference.java

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+/*
+ * Copyright (c) 2016, Red Hat, Inc. and/or its affiliates.
+ * 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.
+ */
+
+/**
+ * @test
+ * @bug 8153925
+ * @summary Tests potential interference between a thread creating and closing
+ *     a WatchService with another thread that is deleting and re-creating the
+ *     directory at around the same time. This scenario tickled a timing bug
+ *     in the Windows implementation.
+ */
+
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.FileSystem;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.WatchService;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import static java.lang.System.out;
+import static java.nio.file.StandardWatchEventKinds.*;
+
+public class DeleteInterference {
+
+    private static final int ITERATIONS_COUNT = 1024;
+
+    /**
+     * Execute two tasks in a thread pool. One task loops on creating and
+     * closing a WatchService, the other task deletes and re-creates the
+     * directory.
+     */
+    public static void main(String[] args) throws Exception {
+        Path testDir = Paths.get(System.getProperty("test.dir", "."));
+        Path dir = Files.createTempDirectory(testDir, "DeleteInterference");
+        ExecutorService pool = Executors.newCachedThreadPool();
+        try {
+            Future<?> task1 = pool.submit(() -> openAndCloseWatcher(dir));
+            Future<?> task2 = pool.submit(() -> deleteAndRecreateDirectory(dir));
+            task1.get();
+            task2.get();
+        } finally {
+            pool.shutdown();
+        }
+    }
+
+    private static void openAndCloseWatcher(Path dir) {
+        FileSystem fs = FileSystems.getDefault();
+        for (int i = 0; i < ITERATIONS_COUNT; i++) {
+            out.printf("open %d begin%n", i);
+            try (WatchService watcher = fs.newWatchService()) {
+                dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
+            } catch (IOException ioe) {
+                // ignore
+            } finally {
+                out.printf("open %d end%n", i);
+            }
+        }
+    }
+
+    private static void deleteAndRecreateDirectory(Path dir) {
+        for (int i = 0; i < ITERATIONS_COUNT; i++) {
+            out.printf("del %d begin%n", i);
+            try {
+                deleteFileTree(dir);
+                Path subdir = Files.createDirectories(dir.resolve("subdir"));
+                Files.createFile(subdir.resolve("test"));
+            } catch (IOException ioe) {
+                // ignore
+            } finally {
+                out.printf("del %d end%n", i);
+            }
+        }
+    }
+
+    private static void deleteFileTree(Path file) {
+        try {
+            if (Files.isDirectory(file)) {
+                try (DirectoryStream<Path> stream = Files.newDirectoryStream(file)) {
+                    for (Path pa : stream) {
+                        deleteFileTree(pa);
+                    }
+                }
+            }
+            Files.delete(file);
+        } catch (IOException ioe) {
+            // ignore
+        }
+    }
+}