org.redline_rpm.Scanner Maven / Gradle / Ivy

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package org.redline_rpm;

import org.redline_rpm.header.AbstractHeader.Entry;
import org.redline_rpm.header.Format;
import org.redline_rpm.header.Header;
import org.redline_rpm.header.Header.HeaderTag;
import org.redline_rpm.payload.CpioHeader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;

import static org.redline_rpm.ChannelWrapper.Key;
import static org.redline_rpm.header.Header.HeaderTag.HEADERIMMUTABLE;
import static org.redline_rpm.header.Signature.SignatureTag.SIGNATURES;

/**
 * The scanner reads an RPM file and outputs useful
 * information about it's contents. The scanner will
 * output the headers of the RPM format itself, as
 * well as the individual headers for the particular
 * packaged content.
 *
 * In addition, the scanner will scan through the
 * payload and output information about each file
 * contained in the embedded CPIO payload.
 */
public class Scanner {
    private static final Logger LOGGER = LoggerFactory.getLogger(Scanner.class);  
    private final PrintStream output;

    public Scanner() {
        this(null);
    }

    public Scanner(final PrintStream out) {
        this.output = out;
    }

    /**
	 * Scans a file and prints out useful information.
	 * This utility reads from standard input, and parses
	 * the binary contents of the RPM file.
	 *
	 * @param args command line arguements
	 * @throws Exception if an error occurs while
	 * reading the RPM file or it's contents
	 */
	public static void main( String[] args) throws Exception {
	    InputStream fios = new FileInputStream ( args[0] );
		ReadableChannelWrapper in = new ReadableChannelWrapper( Channels.newChannel( fios));
        Scanner scanner = new Scanner(System.out);
        Format format = scanner.run(in);
		scanner.log( format.toString());
      Header rpmHeader = format.getHeader();
      scanner.log("Payload compression: "+rpmHeader.getEntry(HeaderTag.PAYLOADCOMPRESSOR));
		InputStream uncompressed = Util.openPayloadStream(rpmHeader, fios);
		in = new ReadableChannelWrapper( Channels.newChannel( uncompressed));
		CpioHeader header;
		int total = 0;
		do {
			header = new CpioHeader();
			total = header.read( in, total);
            scanner.log(header.toString());
			final int skip = header.getFileSize();
			if ( uncompressed.skip( skip) != skip) throw new RuntimeException( "Skip failed.");
			total += header.getFileSize();
		} while ( !header.isLast());
	}

	/**
	 * Reads the headers of an RPM and returns a description of it
	 * and it's format.
	 *
	 * @param in the channel wrapper to read input from
	 * @return information describing the RPM file
	 * @throws IOException if an error occurs reading the file
	 */
	public Format run( ReadableChannelWrapper in) throws IOException {
		Format format = new Format();
        	Key< Integer> headerStartKey = in.start();
		
		Key< Integer> lead = in.start();
		format.getLead().read( in);
		log( "Lead ended at '" + in.finish( lead) + "'.");

		Key< Integer> signature = in.start();
		int count = format.getSignature().read( in);
		Entry sigEntry = format.getSignature().getEntry(SIGNATURES);
		int expected = sigEntry == null ? 0:  ByteBuffer.wrap(( byte[]) sigEntry.getValues(), 8, 4).getInt() / -16;
		log( "Signature ended at '" + in.finish( signature) + "' and contained '" + count + "' headers (expected '" + expected + "').");

        	Integer headerStartPos = in.finish(headerStartKey);
        	format.getHeader().setStartPos(headerStartPos);
		Key< Integer> headerKey = in.start();
		count = format.getHeader().read( in);
		Entry immutableEntry = format.getHeader().getEntry( HEADERIMMUTABLE);
		expected = immutableEntry == null ? 0 : ByteBuffer.wrap(( byte[]) immutableEntry.getValues(), 8, 4).getInt() / -16;
        	Integer headerLength = in.finish(headerKey);
        	format.getHeader().setEndPos(headerStartPos + headerLength);
        	log( "Header ended at '" + headerLength + " and contained '" + count + "' headers (expected '" + expected + "').");

		return format;
	}

    private void log(final String text) {
        if ( output == null){
            LOGGER.info(text);
        }else{
            output.println(text);
        }
    }
}