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/io/RandomAccessFile/FileLengthTest.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * 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 4823133
+ * @summary optimize RandomAccessFile.length() and length() is thread safe now.
+ */
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+/**
+ *
+ * @author vyom.tewari@oracle.com
+ */
+public class FileLengthTest {
+
+    private static final int BUF_SIZE = 4096;
+    private static RandomAccessFile randomAccessFile;
+    private static Thread fileLengthCaller;
+    private static Thread fileContentReader;
+    private static StringBuilder fileContents;
+    private static volatile boolean isFailed = false;
+
+    /**
+     * this thread will call length() in loop
+     */
+    private static void startLengthThread() {
+        if (randomAccessFile == null) {
+            return;
+        }
+        fileLengthCaller = new Thread(() -> {
+            while (true) {
+                try {
+                    long length = randomAccessFile.length();
+                    if (length < 0) {
+                        return;
+                    }
+                } catch (IOException ex) {
+                    return;
+                }
+            }
+        });
+        fileLengthCaller.setName("RandomAccessFile-length-caller");
+        fileLengthCaller.setDaemon(true);
+        fileLengthCaller.start();
+    }
+
+    /**
+     * this thread will call read() and store the content in internal buffer.
+     */
+    private static void startReaderThread() {
+        if (randomAccessFile == null) {
+            return;
+        }
+        fileContentReader = new Thread(() -> {
+            StringBuilder sb = new StringBuilder(BUF_SIZE);
+            int i;
+            byte arr[] = new byte[8];
+            try {
+                while ((i = randomAccessFile.read(arr)) != -1) {
+                    sb.append(new String(arr, 0, i));
+                }
+                if (!sb.toString().equals(fileContents.toString())) {
+                    isFailed = true;
+                }
+            } catch (IOException ex) {
+            }
+        });
+        fileContentReader.setName("RandomAccessFile-content-reader");
+        fileContentReader.setDaemon(true);
+        fileContentReader.start();
+    }
+
+    public static void main(String args[]) {
+        byte arr[] = new byte[BUF_SIZE];
+        String testFile = "testfile.txt";
+        try {
+            createDummyFile(testFile);
+            File file = new File(testFile);
+            file.deleteOnExit();
+            randomAccessFile = new RandomAccessFile(file, "r");
+            int count = randomAccessFile.read(arr);
+            randomAccessFile.seek(0);
+            fileContents = new StringBuilder(BUF_SIZE);
+            fileContents.append(new String(arr, 0, count));
+            startLengthThread();
+            startReaderThread();
+            fileContentReader.join();
+        } catch (FileNotFoundException | InterruptedException ex) {
+        } catch (IOException ex) {
+        } finally {
+            try {
+                randomAccessFile.close();
+            } catch (IOException ex) {
+            }
+        }
+        if (isFailed) {
+            throw new RuntimeException("RandomAccessFile.length() changed the underlying file pointer.");
+        }
+    }
+
+    private static void createDummyFile(String fileName) throws FileNotFoundException, IOException {
+        try (FileOutputStream outputStream = new FileOutputStream(new File(fileName))) {
+            String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
+            int count = 0;
+            while ((count + str.length()) < BUF_SIZE) {
+                outputStream.write(str.getBytes());
+                count += str.length();
+            }
+            outputStream.flush();
+        }
+    }
+}