001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.appender;
018
019import java.io.File;
020import java.io.IOException;
021import java.io.OutputStream;
022import java.io.RandomAccessFile;
023import java.io.Serializable;
024import java.lang.reflect.Method;
025import java.nio.ByteOrder;
026import java.nio.MappedByteBuffer;
027import java.nio.channels.FileChannel;
028import java.security.AccessController;
029import java.security.PrivilegedActionException;
030import java.security.PrivilegedExceptionAction;
031import java.util.HashMap;
032import java.util.Map;
033import java.util.Objects;
034
035import org.apache.logging.log4j.core.Layout;
036import org.apache.logging.log4j.core.util.Closer;
037import org.apache.logging.log4j.core.util.NullOutputStream;
038
039//Lines too long...
040//CHECKSTYLE:OFF
041/**
042 * Extends OutputStreamManager but instead of using a buffered output stream, this class maps a region of a file into
043 * memory and writes to this memory region.
044 * <p>
045 * 
046 * @see <a href="http://www.codeproject.com/Tips/683614/Things-to-Know-about-Memory-Mapped-File-in-Java">
047 *      http://www.codeproject.com/Tips/683614/Things-to-Know-about-Memory-Mapped-File-in-Java</a>
048 * @see <a href="http://bugs.java.com/view_bug.do?bug_id=6893654">http://bugs.java.com/view_bug.do?bug_id=6893654</a>
049 * @see <a href="http://bugs.java.com/view_bug.do?bug_id=4724038">http://bugs.java.com/view_bug.do?bug_id=4724038</a>
050 * @see <a
051 *      href="http://stackoverflow.com/questions/9261316/memory-mapped-mappedbytebuffer-or-direct-bytebuffer-for-db-implementation">
052 *      http://stackoverflow.com/questions/9261316/memory-mapped-mappedbytebuffer-or-direct-bytebuffer-for-db-implementation</a>
053 * 
054 * @since 2.1
055 */
056//CHECKSTYLE:ON
057public class MemoryMappedFileManager extends OutputStreamManager {
058    /**
059     * Default length of region to map.
060     */
061    static final int DEFAULT_REGION_LENGTH = 32 * 1024 * 1024;
062    private static final int MAX_REMAP_COUNT = 10;
063    private static final MemoryMappedFileManagerFactory FACTORY = new MemoryMappedFileManagerFactory();
064    private static final double NANOS_PER_MILLISEC = 1000.0 * 1000.0;
065
066    private final boolean isForce;
067    private final int regionLength;
068    private final String advertiseURI;
069    private final RandomAccessFile randomAccessFile;
070    private final ThreadLocal<Boolean> isEndOfBatch = new ThreadLocal<>();
071    private MappedByteBuffer mappedBuffer;
072    private long mappingOffset;
073
074    protected MemoryMappedFileManager(final RandomAccessFile file, final String fileName, final OutputStream os,
075            final boolean force, final long position, final int regionLength, final String advertiseURI,
076            final Layout<? extends Serializable> layout, final boolean writeHeader) throws IOException {
077        super(os, fileName, layout, writeHeader);
078        this.isForce = force;
079        this.randomAccessFile = Objects.requireNonNull(file, "RandomAccessFile");
080        this.regionLength = regionLength;
081        this.advertiseURI = advertiseURI;
082        this.isEndOfBatch.set(Boolean.FALSE);
083        this.mappedBuffer = mmap(randomAccessFile.getChannel(), getFileName(), position, regionLength);
084        this.mappingOffset = position;
085    }
086
087    /**
088     * Returns the MemoryMappedFileManager.
089     *
090     * @param fileName The name of the file to manage.
091     * @param append true if the file should be appended to, false if it should be overwritten.
092     * @param isForce true if the contents should be flushed to disk on every write
093     * @param regionLength The mapped region length.
094     * @param advertiseURI the URI to use when advertising the file
095     * @param layout The layout.
096     * @return A MemoryMappedFileManager for the File.
097     */
098    public static MemoryMappedFileManager getFileManager(final String fileName, final boolean append,
099            final boolean isForce, final int regionLength, final String advertiseURI,
100            final Layout<? extends Serializable> layout) {
101        return (MemoryMappedFileManager) getManager(fileName, new FactoryData(append, isForce, regionLength,
102                advertiseURI, layout), FACTORY);
103    }
104
105    public Boolean isEndOfBatch() {
106        return isEndOfBatch.get();
107    }
108
109    public void setEndOfBatch(final boolean endOfBatch) {
110        this.isEndOfBatch.set(Boolean.valueOf(endOfBatch));
111    }
112
113    @Override
114    protected synchronized void write(final byte[] bytes, int offset, int length) {
115        super.write(bytes, offset, length); // writes to dummy output stream
116
117        while (length > mappedBuffer.remaining()) {
118            final int chunk = mappedBuffer.remaining();
119            mappedBuffer.put(bytes, offset, chunk);
120            offset += chunk;
121            length -= chunk;
122            remap();
123        }
124        mappedBuffer.put(bytes, offset, length);
125
126        // no need to call flush() if force is true,
127        // already done in AbstractOutputStreamAppender.append
128    }
129
130    private synchronized void remap() {
131        final long offset = this.mappingOffset + mappedBuffer.position();
132        final int length = mappedBuffer.remaining() + regionLength;
133        try {
134            unsafeUnmap(mappedBuffer);
135            final long fileLength = randomAccessFile.length() + regionLength;
136            LOGGER.debug("{} {} extending {} by {} bytes to {}", getClass().getSimpleName(), getName(), getFileName(),
137                    regionLength, fileLength);
138
139            final long startNanos = System.nanoTime();
140            randomAccessFile.setLength(fileLength);
141            final float millis = (float) ((System.nanoTime() - startNanos) / NANOS_PER_MILLISEC);
142            LOGGER.debug("{} {} extended {} OK in {} millis", getClass().getSimpleName(), getName(), getFileName(),
143                    millis);
144            
145            mappedBuffer = mmap(randomAccessFile.getChannel(), getFileName(), offset, length);
146            mappingOffset = offset;
147        } catch (final Exception ex) {
148            logError("unable to remap", ex);
149        }
150    }
151
152    @Override
153    public synchronized void flush() {
154        mappedBuffer.force();
155    }
156
157    @Override
158    public synchronized void close() {
159        final long position = mappedBuffer.position();
160        final long length = mappingOffset + position;
161        try {
162            unsafeUnmap(mappedBuffer);
163        } catch (final Exception ex) {
164            logError("unable to unmap MappedBuffer", ex);
165        }
166        try {
167            LOGGER.debug("MMapAppender closing. Setting {} length to {} (offset {} + position {})", getFileName(),
168                    length, mappingOffset, position);
169            randomAccessFile.setLength(length);
170            randomAccessFile.close();
171        } catch (final IOException ex) {
172            logError("unable to close MemoryMappedFile", ex);
173        }
174    }
175
176    public static MappedByteBuffer mmap(final FileChannel fileChannel, final String fileName, final long start,
177            final int size) throws IOException {
178        for (int i = 1;; i++) {
179            try {
180                LOGGER.debug("MMapAppender remapping {} start={}, size={}", fileName, start, size);
181
182                final long startNanos = System.nanoTime();
183                final MappedByteBuffer map = fileChannel.map(FileChannel.MapMode.READ_WRITE, start, size);
184                map.order(ByteOrder.nativeOrder());
185
186                final float millis = (float) ((System.nanoTime() - startNanos) / NANOS_PER_MILLISEC);
187                LOGGER.debug("MMapAppender remapped {} OK in {} millis", fileName, millis);
188
189                return map;
190            } catch (final IOException e) {
191                if (e.getMessage() == null || !e.getMessage().endsWith("user-mapped section open")) {
192                    throw e;
193                }
194                LOGGER.debug("Remap attempt {}/{} failed. Retrying...", i, MAX_REMAP_COUNT, e);
195                if (i < MAX_REMAP_COUNT) {
196                    Thread.yield();
197                } else {
198                    try {
199                        Thread.sleep(1);
200                    } catch (final InterruptedException ignored) {
201                        Thread.currentThread().interrupt();
202                        throw e;
203                    }
204                }
205            }
206        }
207    }
208
209    private static void unsafeUnmap(final MappedByteBuffer mbb) throws PrivilegedActionException {
210        LOGGER.debug("MMapAppender unmapping old buffer...");
211        final long startNanos = System.nanoTime();
212        AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() {
213            @Override
214            public Object run() throws Exception {
215                final Method getCleanerMethod = mbb.getClass().getMethod("cleaner");
216                getCleanerMethod.setAccessible(true);
217                final Object cleaner = getCleanerMethod.invoke(mbb); // sun.misc.Cleaner instance
218                final Method cleanMethod = cleaner.getClass().getMethod("clean");
219                cleanMethod.invoke(cleaner);
220                return null;
221            }
222        });
223        final float millis = (float) ((System.nanoTime() - startNanos) / NANOS_PER_MILLISEC);
224        LOGGER.debug("MMapAppender unmapped buffer OK in {} millis", millis);
225    }
226
227    /**
228     * Returns the name of the File being managed.
229     *
230     * @return The name of the File being managed.
231     */
232    public String getFileName() {
233        return getName();
234    }
235
236    /**
237     * Returns the length of the memory mapped region.
238     * 
239     * @return the length of the mapped region
240     */
241    public int getRegionLength() {
242        return regionLength;
243    }
244
245    /**
246     * Returns {@code true} if the content of the buffer should be forced to the storage device on every write,
247     * {@code false} otherwise.
248     * 
249     * @return whether each write should be force-sync'ed
250     */
251    public boolean isImmediateFlush() {
252        return isForce;
253    }
254
255    /**
256     * Gets this FileManager's content format specified by:
257     * <p>
258     * Key: "fileURI" Value: provided "advertiseURI" param.
259     * </p>
260     * 
261     * @return Map of content format keys supporting FileManager
262     */
263    @Override
264    public Map<String, String> getContentFormat() {
265        final Map<String, String> result = new HashMap<>(super.getContentFormat());
266        result.put("fileURI", advertiseURI);
267        return result;
268    }
269
270    /**
271     * Factory Data.
272     */
273    private static class FactoryData {
274        private final boolean append;
275        private final boolean force;
276        private final int regionLength;
277        private final String advertiseURI;
278        private final Layout<? extends Serializable> layout;
279
280        /**
281         * Constructor.
282         *
283         * @param append Append to existing file or truncate.
284         * @param force forces the memory content to be written to the storage device on every event
285         * @param regionLength length of the mapped region
286         */
287        public FactoryData(final boolean append, final boolean force, final int regionLength,
288                final String advertiseURI, final Layout<? extends Serializable> layout) {
289            this.append = append;
290            this.force = force;
291            this.regionLength = regionLength;
292            this.advertiseURI = advertiseURI;
293            this.layout = layout;
294        }
295    }
296
297    /**
298     * Factory to create a MemoryMappedFileManager.
299     */
300    private static class MemoryMappedFileManagerFactory
301            implements ManagerFactory<MemoryMappedFileManager, FactoryData> {
302
303        /**
304         * Create a MemoryMappedFileManager.
305         *
306         * @param name The name of the File.
307         * @param data The FactoryData
308         * @return The MemoryMappedFileManager for the File.
309         */
310        @SuppressWarnings("resource")
311        @Override
312        public MemoryMappedFileManager createManager(final String name, final FactoryData data) {
313            final File file = new File(name);
314            final File parent = file.getParentFile();
315            if (null != parent && !parent.exists()) {
316                parent.mkdirs();
317            }
318            if (!data.append) {
319                file.delete();
320            }
321
322            final boolean writeHeader = !data.append || !file.exists();
323            final OutputStream os = NullOutputStream.NULL_OUTPUT_STREAM;
324            RandomAccessFile raf = null;
325            try {
326                raf = new RandomAccessFile(name, "rw");
327                final long position = (data.append) ? raf.length() : 0;
328                raf.setLength(position + data.regionLength);
329                return new MemoryMappedFileManager(raf, name, os, data.force, position, data.regionLength,
330                        data.advertiseURI, data.layout, writeHeader);
331            } catch (final Exception ex) {
332                LOGGER.error("MemoryMappedFileManager (" + name + ") " + ex, ex);
333                Closer.closeSilently(raf);
334            }
335            return null;
336        }
337    }
338}