JVM crashes at libzip.so

Question

My JVM keeps on crashing continuously and unexpectedly at libzip.so all the time. I\'ve filed the bug with Oracle, but decided to see if anyone here has experienced the prob

Answer 1

This is the patched class, sort of nightly built and need to test it. The JGZipOutputStream class can be found here: Creating gzip file using jzlib

JZlib can be found at http://www.jcraft.com/jzlib/

You can patch it either by adding a small jar in the bootstrap path ( -Xbootclasspath/a: ) or unzip/jar the tomcat itself.

Extra bonus is that java impl. is actually faster than the native code.

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package org.apache.coyote.http11.filters;

import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;

import org.apache.coyote.OutputBuffer;
import org.apache.coyote.Response;
import org.apache.coyote.http11.OutputFilter;
import org.apache.tomcat.util.buf.ByteChunk;

import bestsss.util.JGZipOutputStream;

import com.jcraft.jzlib.JZlib;

/**
 * Gzip output filter.
 * 
 * @author Remy Maucherat
 */
public class GzipOutputFilter implements OutputFilter {


    /**
     * Logger.
     */
    protected static org.apache.juli.logging.Log log =
        org.apache.juli.logging.LogFactory.getLog(GzipOutputFilter.class);


    // ----------------------------------------------------- Instance Variables


    /**
     * Next buffer in the pipeline.
     */
    protected OutputBuffer buffer;


    /**
     * Compression output stream.
     */
    protected OutputStream compressionStream = null;


    /**
     * Fake internal output stream.
     */
    protected OutputStream fakeOutputStream = new FakeOutputStream();


    // --------------------------------------------------- OutputBuffer Methods


    /**
     * Write some bytes.
     * 
     * @return number of bytes written by the filter
     */
    @Override
    public int doWrite(ByteChunk chunk, Response res)
        throws IOException {
        if (compressionStream == null) {
            compressionStream = new JGZipOutputStream(fakeOutputStream, new byte[Math.min(32768, Math.max(2048, Integer.highestOneBit(chunk.getLength()-1)<<1))]);
        }
        compressionStream.write(chunk.getBytes(), chunk.getStart(), 
                                chunk.getLength());
        return chunk.getLength();
    }


    @Override
    public long getBytesWritten() {
        return buffer.getBytesWritten();
    }


    // --------------------------------------------------- OutputFilter Methods

    /**
     * Added to allow flushing to happen for the gzip'ed outputstream
     */
    public void flush() {
        if (compressionStream != null) {
            try {
                if (log.isDebugEnabled()) {
                    log.debug("Flushing the compression stream!");
                }
                compressionStream.flush();
            } catch (IOException e) {
                if (log.isDebugEnabled()) {
                    log.debug("Ignored exception while flushing gzip filter", e);
                }
            }
        }
    }

    /**
     * Some filters need additional parameters from the response. All the 
     * necessary reading can occur in that method, as this method is called
     * after the response header processing is complete.
     */
    @Override
    public void setResponse(Response response) {
        // NOOP: No need for parameters from response in this filter
    }


    /**
     * Set the next buffer in the filter pipeline.
     */
    @Override
    public void setBuffer(OutputBuffer buffer) {
        this.buffer = buffer;
    }


    /**
     * End the current request. It is acceptable to write extra bytes using
     * buffer.doWrite during the execution of this method.
     */
    @Override
    public long end()
        throws IOException {
        if (compressionStream == null) {
            compressionStream = new JGZipOutputStream(fakeOutputStream, new byte[128]);
        }        
        compressionStream.close();
        return ((OutputFilter) buffer).end();
    }


    /**
     * Make the filter ready to process the next request.
     */
    @Override
    public void recycle() {
        // Set compression stream to null
        compressionStream = null;
    }


    // ------------------------------------------- FakeOutputStream Inner Class


    protected class FakeOutputStream
        extends OutputStream {
        protected ByteChunk outputChunk = new ByteChunk();
        protected byte[] singleByteBuffer = new byte[1];
        @Override
        public void write(int b)
            throws IOException {
            // Shouldn't get used for good performance, but is needed for 
            // compatibility with Sun JDK 1.4.0
            singleByteBuffer[0] = (byte) (b & 0xff);
            outputChunk.setBytes(singleByteBuffer, 0, 1);
            buffer.doWrite(outputChunk, null);
        }
        @Override
        public void write(byte[] b, int off, int len)
            throws IOException {
            outputChunk.setBytes(b, off, len);
            buffer.doWrite(outputChunk, null);
        }
        @Override
        public void flush() throws IOException {/*NOOP*/}
        @Override
        public void close() throws IOException {/*NOOP*/}
    }


}