(WiP) Global image sync

14 files changed, 323 insertions, 520 deletions

diff --git a/dozentenmodulserver/src/main/java/fi/iki/elonen/NanoHTTPD.java b/dozentenmodulserver/src/main/java/fi/iki/elonen/NanoHTTPD.java
index e4d265ae..f6312985 100644
--- a/dozentenmodulserver/src/main/java/fi/iki/elonen/NanoHTTPD.java
+++ b/dozentenmodulserver/src/main/java/fi/iki/elonen/NanoHTTPD.java
@@ -69,7 +69,7 @@ import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.log4j.Logger;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
-import org.openslx.bwlp.sat.util.GrowingThreadPoolExecutor;
+import org.openslx.util.GrowingThreadPoolExecutor;
 
 /**
  * A simple, tiny, nicely embeddable HTTP server in Java
@@ -458,7 +458,7 @@ public abstract class NanoHTTPD implements Runnable {
 	 */
 	public static class DefaultAsyncRunner implements AsyncRunner {
 		private ExecutorService pool = new GrowingThreadPoolExecutor(2, 16, 1, TimeUnit.MINUTES,
-				new ArrayBlockingQueue<Runnable>(16));
+				new ArrayBlockingQueue<Runnable>(4));
 
 		@Override
 		public void exec(Runnable code) {
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/App.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/App.java
index 8e615ef1..ed8cbb7e 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/App.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/App.java
@@ -60,7 +60,7 @@ public class App {
 			LOGGER.fatal("Could not load configuration", e1);
 			System.exit(1);
 		}
-		
+
 		// Update database schema if applicable
 		try {
 			Updater.updateDatabase();
@@ -68,7 +68,7 @@ public class App {
 			LOGGER.fatal("Updating/checking the database layout failed.");
 			return;
 		}
-		
+
 		if (Identity.loadCertificate() == null) {
 			LOGGER.error("Could not set up TLS/SSL requirements, exiting");
 			System.exit(1);
@@ -100,8 +100,7 @@ public class App {
 
 		SSLContext ctx = null;
 		if (Configuration.getMasterServerSsl()) {
-			ctx = SSLContext.getInstance("TLSv1.2");
-			ctx.init(null, null, null);
+			ctx = Configuration.getMasterServerSslContext();
 		}
 		ThriftManager.setMasterServerAddress(ctx, Configuration.getMasterServerAddress(),
 				Configuration.getMasterServerPort(), 30000);
@@ -114,12 +113,12 @@ public class App {
 		}
 		if (OrganizationList.get() == null || OrganizationList.get().isEmpty()) {
 			LOGGER.fatal("Could not get initial organization list from master server."
-				+ " Please make sure this server can connect to the internet.");
+					+ " Please make sure this server can connect to the internet.");
 			return;
 		}
 		if (OperatingSystemList.get() == null || OperatingSystemList.get().isEmpty()) {
 			LOGGER.fatal("Could not get initial operating system list from master server."
-				+ " Please make sure this server can connect to the internet.");
+					+ " Please make sure this server can connect to the internet.");
 			return;
 		}
 
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbImage.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbImage.java
index 55fa02b2..8aafe862 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbImage.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbImage.java
@@ -891,15 +891,35 @@ public class DbImage {
 		}
 	}
 
+	public static List<ByteBuffer> getBlockHashes(String imageVersionId) throws SQLException {
+		try (MysqlConnection connection = Database.getConnection()) {
+			return getBlockHashes(connection, imageVersionId);
+		} catch (SQLException e) {
+			LOGGER.error("Query failed in DbImage.getBlockHashes()", e);
+			throw e;
+		}
+	}
+
 	private static List<ByteBuffer> getBlockHashes(MysqlConnection connection, String imageVersionId)
 			throws SQLException {
-		MysqlStatement stmt = connection.prepareStatement("SELECT blocksha1 FROM imageblock"
+		MysqlStatement stmt = connection.prepareStatement("SELECT startbyte, blocksha1 FROM imageblock"
 				+ " WHERE imageversionid = :imageversionid ORDER BY startbyte ASC");
 		stmt.setString("imageversionid", imageVersionId);
 		ResultSet rs = stmt.executeQuery();
 		List<ByteBuffer> list = new ArrayList<>();
+		long expectedOffset = 0;
 		while (rs.next()) {
-			list.add(ByteBuffer.wrap(rs.getBytes("blocksha1")));
+			long currentOffset = rs.getLong("startbyte");
+			if (currentOffset < expectedOffset)
+				continue;
+			while (currentOffset > expectedOffset) {
+				list.add(null);
+				expectedOffset += FileChunk.CHUNK_SIZE;
+			}
+			if (currentOffset == expectedOffset) {
+				list.add(ByteBuffer.wrap(rs.getBytes("blocksha1")));
+				expectedOffset += FileChunk.CHUNK_SIZE;
+			}
 		}
 		return list;
 	}
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbUser.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbUser.java
index 87a05d63..81e4721d 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbUser.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/database/mappers/DbUser.java
@@ -67,6 +67,24 @@ public class DbUser {
 		}
 	}
 
+	public static UserInfo getOrNull(String userId) throws SQLException {
+		try (MysqlConnection connection = Database.getConnection()) {
+			MysqlStatement stmt = connection.prepareStatement("SELECT userid, firstname, lastname, email, organizationid,"
+					+ " lastlogin, canlogin, issuperuser, emailnotifications"
+					+ " FROM user WHERE userid = :userid");
+			stmt.setString("userid", userId);
+			ResultSet rs = stmt.executeQuery();
+			if (rs.next()) {
+				return new UserInfo(rs.getString("userid"), rs.getString("firstname"),
+						rs.getString("lastname"), rs.getString("email"), rs.getString("organizationid"));
+			}
+			return null;
+		} catch (SQLException e) {
+			LOGGER.error("Query failed in DbUser.getAll()", e);
+			throw e;
+		}
+	}
+
 	/**
 	 * Get local-only information for given user.
 	 * 
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/FileServer.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/FileServer.java
index 844ffb74..a4e8de3c 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/FileServer.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/FileServer.java
@@ -8,9 +8,9 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
-import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.SynchronousQueue;
 import java.util.concurrent.TimeUnit;
 
 import javax.net.ssl.SSLContext;
@@ -21,7 +21,6 @@ import org.openslx.bwlp.sat.database.models.LocalImageVersion;
 import org.openslx.bwlp.sat.util.Constants;
 import org.openslx.bwlp.sat.util.FileSystem;
 import org.openslx.bwlp.sat.util.Formatter;
-import org.openslx.bwlp.sat.util.GrowingThreadPoolExecutor;
 import org.openslx.bwlp.sat.util.Identity;
 import org.openslx.bwlp.sat.util.PrioThreadFactory;
 import org.openslx.bwlp.thrift.iface.ImageDetailsRead;
@@ -32,6 +31,7 @@ import org.openslx.filetransfer.IncomingEvent;
 import org.openslx.filetransfer.Listener;
 import org.openslx.filetransfer.Uploader;
 import org.openslx.thrifthelper.Comparators;
+import org.openslx.util.GrowingThreadPoolExecutor;
 
 public class FileServer implements IncomingEvent {
 
@@ -45,7 +45,7 @@ public class FileServer implements IncomingEvent {
 	private final Listener sslListener;
 
 	private final ExecutorService transferPool = new GrowingThreadPoolExecutor(1, Constants.MAX_UPLOADS
-			+ Constants.MAX_DOWNLOADS, 1, TimeUnit.MINUTES, new ArrayBlockingQueue<Runnable>(1),
+			+ Constants.MAX_DOWNLOADS, 1, TimeUnit.MINUTES, new SynchronousQueue<Runnable>(),
 			new PrioThreadFactory("ClientTransferPool", Thread.NORM_PRIORITY - 2));
 
 	/**
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/IncomingDataTransfer.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/IncomingDataTransfer.java
index 92f533e8..4ce8cc0a 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/IncomingDataTransfer.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/IncomingDataTransfer.java
@@ -3,11 +3,9 @@ package org.openslx.bwlp.sat.fileserv;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.io.RandomAccessFile;
-import java.security.NoSuchAlgorithmException;
 import java.sql.SQLException;
-import java.util.ArrayList;
 import java.util.List;
+import java.util.UUID;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -15,12 +13,10 @@ import javax.net.ssl.SSLContext;
 
 import org.apache.log4j.Logger;
 import org.openslx.bwlp.sat.database.mappers.DbImage;
-import org.openslx.bwlp.sat.thrift.ThriftUtil;
 import org.openslx.bwlp.sat.util.Configuration;
 import org.openslx.bwlp.sat.util.Constants;
 import org.openslx.bwlp.sat.util.FileSystem;
 import org.openslx.bwlp.sat.util.Formatter;
-import org.openslx.bwlp.sat.util.Util;
 import org.openslx.bwlp.thrift.iface.ImageDetailsRead;
 import org.openslx.bwlp.thrift.iface.ImagePublishData;
 import org.openslx.bwlp.thrift.iface.ImageVersionWrite;
@@ -28,43 +24,20 @@ import org.openslx.bwlp.thrift.iface.TransferInformation;
 import org.openslx.bwlp.thrift.iface.TransferState;
 import org.openslx.bwlp.thrift.iface.TransferStatus;
 import org.openslx.bwlp.thrift.iface.UserInfo;
-import org.openslx.filetransfer.DataReceivedCallback;
 import org.openslx.filetransfer.Downloader;
-import org.openslx.filetransfer.FileRange;
-import org.openslx.filetransfer.WantRangeCallback;
-import org.openslx.filetransfer.util.ChunkList;
 import org.openslx.filetransfer.util.FileChunk;
-import org.openslx.filetransfer.util.HashChecker;
-import org.openslx.filetransfer.util.HashChecker.HashCheckCallback;
-import org.openslx.filetransfer.util.HashChecker.HashResult;
+import org.openslx.filetransfer.util.IncomingTransferBase;
+import org.openslx.util.ThriftUtil;
 import org.openslx.util.vm.DiskImage;
 import org.openslx.util.vm.DiskImage.UnknownImageFormatException;
 
-public class IncomingDataTransfer extends AbstractTransfer implements HashCheckCallback {
+public class IncomingDataTransfer extends IncomingTransferBase {
 
 	private static final Logger LOGGER = Logger.getLogger(IncomingDataTransfer.class);
 
 	private static final long MIN_FREE_SPACE_BYTES = FileChunk.CHUNK_SIZE * (2 + Constants.MAX_UPLOADS);
 
 	/**
-	 * Self reference for inner classes.
-	 */
-	private final IncomingDataTransfer activeUpload = this;
-
-	/**
-	 * Remote peer is uploading, so on our end, we have Downloaders
-	 */
-	private List<Downloader> downloads = new ArrayList<>();
-
-	private final File tmpFileName;
-
-	private final RandomAccessFile tmpFileHandle;
-
-	private final ChunkList chunks;
-
-	private final long fileSize;
-
-	/**
 	 * User owning this uploaded file.
 	 */
 	private final UserInfo owner;
@@ -80,11 +53,6 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 	private ImageVersionWrite versionSettings = null;
 
 	/**
-	 * TransferState of this upload
-	 */
-	private TransferState state = TransferState.IDLE;
-
-	/**
 	 * Description of this VM - binary dump of e.g. the *.vmx file (VMware)
 	 */
 	private final byte[] machineDescription;
@@ -96,44 +64,24 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 	private final AtomicBoolean versionWrittenToDb = new AtomicBoolean();
 
 	/**
-	 * Whether file is (still) writable. Used for the file transfer callbacks.
-	 */
-	private boolean fileWritable = true;
-
-	/**
 	 * Set if this is a download from the master server
 	 */
 	private final TransferInformation masterTransferInfo;
 
-	private static final HashChecker hashChecker;
-
-	static {
-		HashChecker hc;
-		try {
-			hc = new HashChecker("SHA-1", Constants.HASHCHECK_QUEUE_LEN);
-		} catch (NoSuchAlgorithmException e) {
-			hc = null;
-		}
-		hashChecker = hc;
-	}
-
 	public IncomingDataTransfer(String uploadId, UserInfo owner, ImageDetailsRead image,
 			File destinationFile, long fileSize, List<byte[]> sha1Sums, byte[] machineDescription)
 			throws FileNotFoundException {
-		super(uploadId);
-		this.tmpFileName = destinationFile;
-		this.tmpFileHandle = new RandomAccessFile(destinationFile, "rw");
-		this.chunks = new ChunkList(fileSize, hashChecker == null ? null : sha1Sums);
+		super(uploadId, destinationFile, fileSize, sha1Sums);
 		this.owner = owner;
 		this.image = image;
-		this.fileSize = fileSize;
 		this.machineDescription = machineDescription;
 		this.masterTransferInfo = null;
 	}
 
 	public IncomingDataTransfer(ImagePublishData publishData, File tmpFile, TransferInformation transferInfo)
 			throws FileNotFoundException {
-		super(publishData.imageVersionId);
+		super(UUID.randomUUID().toString(), tmpFile, publishData.fileSize,
+				ThriftUtil.unwrapByteBufferList(transferInfo.blockHashes));
 		ImageDetailsRead idr = new ImageDetailsRead();
 		idr.setCreateTime(publishData.createTime);
 		idr.setDescription(publishData.description);
@@ -147,13 +95,8 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 		idr.setUpdaterId(publishData.user.userId);
 		idr.setUpdateTime(publishData.createTime);
 		idr.setVirtId(publishData.virtId);
-		this.tmpFileName = tmpFile;
-		this.tmpFileHandle = new RandomAccessFile(tmpFile, "rw");
-		this.chunks = new ChunkList(publishData.fileSize, hashChecker == null ? null
-				: ThriftUtil.unwrapByteBufferList(transferInfo.blockHashes));
 		this.owner = publishData.user;
 		this.image = idr;
-		this.fileSize = publishData.fileSize;
 		this.machineDescription = ThriftUtil.unwrapByteBuffer(transferInfo.machineDescription);
 		this.masterTransferInfo = transferInfo;
 		this.versionSettings = new ImageVersionWrite(false);
@@ -167,10 +110,8 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 		if (masterTransferInfo == null)
 			return;
 		synchronized (this) {
-			synchronized (downloads) {
-				if (downloads.size() >= 1) // TODO What to pick here?
-					return;
-			}
+			if (getActiveConnectionCount() >= 1)
+				return;
 			Downloader downloader = null;
 			if (masterTransferInfo.plainPort != 0) {
 				try {
@@ -221,114 +162,33 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 	}
 
 	/**
-	 * Add another connection for this file transfer.
-	 * 
-	 * @param connection
-	 * @return true if the connection is accepted, false if it should be
-	 *         discarded
-	 */
-	public synchronized boolean addConnection(final Downloader connection, ExecutorService pool) {
-		if (state == TransferState.FINISHED || state == TransferState.ERROR)
-			return false;
-		synchronized (downloads) {
-			if (downloads.size() >= Constants.MAX_CONNECTIONS_PER_TRANSFER)
-				return false;
-			downloads.add(connection);
-		}
-		try {
-			pool.execute(new Runnable() {
-				@Override
-				public void run() {
-					CbHandler cbh = new CbHandler(connection);
-					if (!connection.download(cbh, cbh)) {
-						if (cbh.currentChunk != null) {
-							// If the download failed and we have a current chunk, put it back into
-							// the queue, so it will be handled again later...
-							chunks.markFailed(cbh.currentChunk);
-						}
-						LOGGER.warn("Download of " + tmpFileName.getAbsolutePath() + " failed");
-					}
-					if (state != TransferState.FINISHED && state != TransferState.ERROR) {
-						lastActivityTime.set(System.currentTimeMillis());
-					}
-					synchronized (downloads) {
-						downloads.remove(connection);
-					}
-					if (chunks.isComplete()) {
-						finishUpload();
-					}
-				}
-			});
-		} catch (Exception e) {
-			LOGGER.warn("threadpool rejected the incoming file transfer", e);
-			synchronized (downloads) {
-				downloads.remove(connection);
-			}
-			return false;
-		}
-		if (state == TransferState.IDLE) {
-			state = TransferState.WORKING;
-		}
-		return true;
-	}
-
-	/**
-	 * Write some data to the local file. Thread safe so we can
-	 * have multiple concurrent connections.
-	 * 
-	 * @param fileOffset
-	 * @param dataLength
-	 * @param data
-	 * @return
-	 */
-	private void writeFileData(long fileOffset, int dataLength, byte[] data) {
-		synchronized (tmpFileHandle) {
-			if (state != TransferState.WORKING)
-				throw new IllegalStateException("Cannot write to file if state != WORKING");
-			try {
-				tmpFileHandle.seek(fileOffset);
-				tmpFileHandle.write(data, 0, dataLength);
-			} catch (IOException e) {
-				LOGGER.error("Cannot write to '" + tmpFileName
-						+ "'. Disk full, network storage error, bad permissions, ...?", e);
-				fileWritable = false;
-			}
-		}
-		if (!fileWritable) {
-			cancel();
-		}
-	}
-
-	/**
 	 * Called when the upload finished.
 	 */
-	private synchronized void finishUpload() {
-		synchronized (tmpFileHandle) {
-			if (state != TransferState.WORKING)
-				return;
-			Util.safeClose(tmpFileHandle);
-			state = TransferState.FINISHED;
-		}
+	@Override
+	protected synchronized boolean finishIncomingTransfer() {
+		if (getState() != TransferState.FINISHED)
+			return false;
 		potentialFinishTime.set(System.currentTimeMillis());
 		// If owner is not set, this was a repair-transfer, which downloads directly to the existing target file.
 		// Nothing more to do in that case.
 		if (isRepairUpload())
-			return;
+			return true;
 		LOGGER.info("Finalizing uploaded image " + image.imageName);
 		// Ready to go. First step: Rename temp file to something usable
 		String ext = "img";
 		try {
-			ext = new DiskImage(tmpFileName).format.extension;
+			ext = new DiskImage(getTmpFileName()).format.extension;
 		} catch (IOException | UnknownImageFormatException e1) {
 		}
-		File destination = new File(tmpFileName.getParent(), Formatter.vmName(owner, image.imageName, ext));
+		File destination = new File(getTmpFileName().getParent(), Formatter.vmName(owner, image.imageName,
+				ext));
 		// Sanity check: destination should be a sub directory of the vmStorePath
 		String relPath = FileSystem.getRelativePath(destination, Configuration.getVmStoreBasePath());
 		if (relPath == null) {
 			LOGGER.warn(destination.getAbsolutePath() + " is not a subdir of "
 					+ Configuration.getVmStoreBasePath().getAbsolutePath());
 			cancel();
-			return;
+			return false;
 		}
 		if (relPath.length() > 200) {
 			LOGGER.error("Generated file name is >200 chars. DB will not like it");
@@ -338,7 +198,7 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 		boolean ret = false;
 		Exception renameException = null;
 		try {
-			ret = tmpFileName.renameTo(destination);
+			ret = getTmpFileName().renameTo(destination);
 		} catch (Exception e) {
 			ret = false;
 			renameException = e;
@@ -346,43 +206,34 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 		if (!ret) {
 			// Rename failed :-(
 			LOGGER.warn(
-					"Could not rename '" + tmpFileName.getAbsolutePath() + "' to '"
+					"Could not rename '" + getTmpFileName().getAbsolutePath() + "' to '"
 							+ destination.getAbsolutePath() + "'", renameException);
 			cancel();
-			return;
+			return false;
 		}
 
 		// Now insert meta data into DB
 		try {
 			synchronized (versionWrittenToDb) {
-				DbImage.createImageVersion(image.imageBaseId, getId(), owner, fileSize, relPath,
-						versionSettings, chunks, machineDescription);
+				DbImage.createImageVersion(image.imageBaseId, getId(), owner, getFileSize(), relPath,
+						versionSettings, getChunks(), machineDescription);
 				versionWrittenToDb.set(true);
 			}
 		} catch (SQLException e) {
 			LOGGER.error("Error finishing upload: Inserting version to DB failed", e);
-			state = TransferState.ERROR;
 			// Also delete uploaded file, as there is no reference to it
 			FileSystem.deleteAsync(destination);
 			cancel();
-			return;
+			return false;
 		}
+		return true;
 	}
 
 	@Override
 	public synchronized void cancel() {
-		if (state != TransferState.FINISHED && state != TransferState.ERROR) {
-			state = TransferState.ERROR;
-		}
-		synchronized (downloads) {
-			for (Downloader download : downloads) {
-				download.cancel();
-			}
-		}
-		lastActivityTime.set(0);
-		Util.safeClose(tmpFileHandle);
-		if (!isRepairUpload() && tmpFileName.exists()) {
-			FileSystem.deleteAsync(tmpFileName);
+		super.cancel();
+		if (!isRepairUpload() && getTmpFileName().exists()) {
+			FileSystem.deleteAsync(getTmpFileName());
 		}
 	}
 
@@ -399,203 +250,46 @@ public class IncomingDataTransfer extends AbstractTransfer implements HashCheckC
 		return this.owner;
 	}
 
-	public File getDestinationFile() {
-		return this.tmpFileName;
-	}
-
-	public long getSize() {
-		return this.fileSize;
-	}
-
-	/**
-	 * Callback class for an instance of the Downloader, which supplies
-	 * the Downloader with wanted file ranges, and handles incoming data.
-	 */
-	private class CbHandler implements WantRangeCallback, DataReceivedCallback {
-		/**
-		 * The current chunk being transfered.
-		 */
-		private FileChunk currentChunk = null;
-		/**
-		 * Current buffer to receive to
-		 */
-		private byte[] buffer = new byte[FileChunk.CHUNK_SIZE];
-		/**
-		 * Downloader object
-		 */
-		private final Downloader downloader;
-
-		private CbHandler(Downloader downloader) {
-			this.downloader = downloader;
-		}
-
-		@Override
-		public boolean dataReceived(long fileOffset, int dataLength, byte[] data) {
-			if (currentChunk == null)
-				throw new IllegalStateException("dataReceived without current chunk");
-			if (!currentChunk.range.contains(fileOffset, fileOffset + dataLength))
-				throw new IllegalStateException("dataReceived with file data out of range");
-			System.arraycopy(data, 0, buffer, (int) (fileOffset - currentChunk.range.startOffset), dataLength);
-			return fileWritable;
-		}
-
-		@Override
-		public FileRange get() {
-			if (currentChunk != null) {
-				if (hashChecker != null && currentChunk.getSha1Sum() != null) {
-					try {
-						hashChecker.queue(currentChunk, buffer, activeUpload);
-					} catch (InterruptedException e) {
-						Thread.currentThread().interrupt();
-						return null;
-					}
-					try {
-						buffer = new byte[buffer.length];
-					} catch (OutOfMemoryError e) {
-						// Usually catching OOM errors is a bad idea, but it's quite safe here as
-						// we know exactly where it happened, no hidden sub-calls through 20 objects.
-						// The most likely cause here is that the hash checker/disk cannot keep up
-						// writing out completed chunks, so we just sleep a bit and try again. If it still
-						// fails, we exit completely.
-						try {
-							Thread.sleep(6000);
-						} catch (InterruptedException e1) {
-							Thread.currentThread().interrupt();
-							return null;
-						}
-						// Might raise OOM again, but THIS TIME I MEAN IT
-						try {
-							buffer = new byte[buffer.length];
-						} catch (OutOfMemoryError e2) {
-							downloader.sendErrorCode("Out of RAM");
-							cancel();
-						}
-					}
-				} else {
-					// We have no hash checker or the hash for the current chunk is unknown - flush to disk
-					writeFileData(currentChunk.range.startOffset, currentChunk.range.getLength(), buffer);
-					chunks.markSuccessful(currentChunk);
-				}
-			}
-			// Get next missing chunk
-			try {
-				currentChunk = chunks.getMissing();
-			} catch (InterruptedException e) {
-				Thread.currentThread().interrupt();
-				cancel();
-				return null;
-			}
-			if (currentChunk == null) {
-				return null; // No more chunks, returning null tells the Downloader we're done.
-			}
-			// Check remaining disk space and abort if it's too low
-			long space = FileSystem.getAvailableStorageBytes();
-			if (space != -1 && space < MIN_FREE_SPACE_BYTES) {
-				downloader.sendErrorCode("Out of disk space");
-				LOGGER.error("Out of space: Cancelling upload of "
-						+ (image == null ? "image" : image.imageName) + " by "
-						+ Formatter.userFullName(owner));
-				cancel();
-				return null;
-			}
-			return currentChunk.range;
-		}
-	}
-
 	public synchronized TransferStatus getStatus() {
-		return new TransferStatus(chunks.getStatusArray(), state);
+		return new TransferStatus(getChunks().getStatusArray(), getState());
 	}
 
 	@Override
-	public void hashCheckDone(HashResult result, byte[] data, FileChunk chunk) {
-		if (state != TransferState.IDLE && state != TransferState.WORKING)
-			return;
-		switch (result) {
-		case FAILURE:
-			LOGGER.warn("Hash check of chunk " + chunk.toString()
-					+ " could not be executed. Assuming valid :-(");
-			// Fall through
-		case VALID:
-			if (!chunk.isWrittenToDisk()) {
-				writeFileData(chunk.range.startOffset, chunk.range.getLength(), data);
-			}
-			chunks.markSuccessful(chunk);
-			if (chunks.isComplete()) {
-				finishUpload();
-			}
-			break;
-		case INVALID:
-			LOGGER.warn("Hash check of chunk " + chunk.getChunkIndex() + " resulted in mismatch "
-					+ chunk.getFailCount() + "x :-(");
-			chunks.markFailed(chunk);
-			break;
-		}
+	public boolean isActive() {
+		return getState() == TransferState.IDLE || getState() == TransferState.WORKING;
 	}
 
-	private byte[] loadChunkFromFile(FileChunk chunk) {
-		synchronized (tmpFileHandle) {
-			if (state != TransferState.IDLE && state != TransferState.WORKING)
-				return null;
-			try {
-				tmpFileHandle.seek(chunk.range.startOffset);
-				byte[] buffer = new byte[chunk.range.getLength()];
-				tmpFileHandle.readFully(buffer);
-				return buffer;
-			} catch (IOException e) {
-				LOGGER.error(
-						"Could not read chunk " + chunk.getChunkIndex() + " of File "
-								+ tmpFileName.toString(), e);
-				return null;
-			}
+	@Override
+	protected void finalize() {
+		try {
+			super.finalize();
+		} catch (Throwable t) {
+		}
+		try {
+			cancel();
+		} catch (Throwable t) {
 		}
 	}
 
-	public void updateBlockHashList(List<byte[]> hashList) {
-		if (state != TransferState.IDLE && state != TransferState.WORKING) {
-			LOGGER.debug(this.getId() + ": Rejecting block hash list in state " + state);
-			return;
-		}
-		if (hashChecker == null || hashList == null) {
-			LOGGER.debug(this.getId() + ": Rejecting block hash list: No hasher");
-			return;
-		}
-		chunks.updateSha1Sums(hashList);
-		FileChunk chunk;
-		while (null != (chunk = chunks.getUnhashedComplete())) {
-			byte[] data = loadChunkFromFile(chunk);
-			if (data == null) {
-				LOGGER.warn("Will mark unloadable chunk as valid :-(");
-				chunks.markSuccessful(chunk);
-				continue;
-			}
-			try {
-				hashChecker.queue(chunk, data, this);
-			} catch (InterruptedException e) {
-				Thread.currentThread().interrupt();
-				return;
-			}
-		}
+	@Override
+	protected boolean hasEnoughFreeSpace() {
+		return FileSystem.getAvailableStorageBytes() > MIN_FREE_SPACE_BYTES;
 	}
 
 	@Override
-	public boolean isActive() {
-		return state == TransferState.IDLE || state == TransferState.WORKING;
+	public TransferInformation getTransferInfo() {
+		return new TransferInformation(getId(), FileServer.instance().getPlainPort(), FileServer.instance()
+				.getSslPort());
 	}
 
 	@Override
-	public int getActiveConnectionCount() {
-		return downloads.size();
+	public String getRelativePath() {
+		return FileSystem.getRelativePath(getTmpFileName(), Configuration.getVmStoreBasePath());
 	}
 
 	@Override
-	protected void finalize() {
-		try {
-			Util.safeClose(tmpFileHandle);
-			if (tmpFileName.exists()) {
-				FileSystem.deleteAsync(tmpFileName);
-			}
-		} catch (Throwable t) {
-		}
+	protected void chunkStatusChanged(FileChunk chunk) {
+		// TODO Update in DB in case this is a repair upload
 	}
 
 }
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/OutgoingDataTransfer.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/OutgoingDataTransfer.java
index 31c219aa..581d7ba5 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/OutgoingDataTransfer.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/OutgoingDataTransfer.java
@@ -1,12 +1,18 @@
 package org.openslx.bwlp.sat.fileserv;
 
 import java.io.File;
+import java.io.IOException;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.UUID;
 import java.util.concurrent.ExecutorService;
 
 import org.apache.log4j.Logger;
+import org.openslx.bwlp.sat.util.Configuration;
 import org.openslx.bwlp.sat.util.Constants;
+import org.openslx.bwlp.thrift.iface.TransferInformation;
 import org.openslx.filetransfer.Uploader;
 
 public class OutgoingDataTransfer extends AbstractTransfer {
@@ -20,19 +26,75 @@ public class OutgoingDataTransfer extends AbstractTransfer {
 
 	private final File sourceFile;
 
+	private final TransferInformation masterTransferInfo;
+
 	private boolean isCanceled = false;
 
+	/**
+	 * For downloads by clients.
+	 * 
+	 * @param uuid UUID of this transfer
+	 * @param file file to send to client
+	 */
 	public OutgoingDataTransfer(String uuid, File file) {
 		super(uuid);
 		this.sourceFile = file;
+		this.masterTransferInfo = null;
+	}
+
+	/**
+	 * For uploads to the master server.
+	 * 
+	 * @param transferInfo TI received by master server when it granted the
+	 *            upload
+	 * @param absFile file to send to master server
+	 */
+	public OutgoingDataTransfer(TransferInformation transferInfo, File absFile) {
+		super(UUID.randomUUID().toString());
+		this.masterTransferInfo = transferInfo;
+		this.sourceFile = absFile;
 	}
 
 	/**
 	 * Called periodically if this is a transfer from the master server, so we
 	 * can make sure the transfer is running.
 	 */
-	public void heartBeat(ExecutorService pool) {
-		// TODO
+	public synchronized void heartBeat(ExecutorService pool) {
+		if (isCanceled || masterTransferInfo == null)
+			return;
+		synchronized (uploads) {
+			if (uploads.size() >= 1)
+				return;
+		}
+		Uploader uploader = null;
+		Exception connectException = null;
+		if (masterTransferInfo.plainPort != 0) {
+			// Try plain
+			try {
+				uploader = new Uploader(Configuration.getMasterServerAddress(), masterTransferInfo.plainPort,
+						10000, null, masterTransferInfo.token);
+			} catch (IOException e) {
+				uploader = null;
+				connectException = e;
+			}
+		}
+		if (uploader == null && masterTransferInfo.sslPort != 0 && Configuration.getMasterServerSsl()) {
+			// Try SSL
+			try {
+				uploader = new Uploader(Configuration.getMasterServerAddress(), masterTransferInfo.sslPort,
+						10000, Configuration.getMasterServerSslContext(), masterTransferInfo.token);
+			} catch (KeyManagementException | NoSuchAlgorithmException | IOException e) {
+				connectException = e;
+			}
+		}
+		if (uploader == null) {
+			LOGGER.debug("Cannot connect to master server for uploading", connectException);
+		} else {
+			synchronized (uploads) {
+				uploads.add(uploader);
+			}
+			runConnectionInternal(uploader, pool);
+		}
 	}
 
 	/**
@@ -43,7 +105,7 @@ public class OutgoingDataTransfer extends AbstractTransfer {
 	 *         discarded
 	 */
 	public synchronized boolean addConnection(final Uploader connection, ExecutorService pool) {
-		if (isCanceled)
+		if (isCanceled || masterTransferInfo != null)
 			return false;
 		potentialFinishTime.set(0);
 		synchronized (uploads) {
@@ -51,16 +113,19 @@ public class OutgoingDataTransfer extends AbstractTransfer {
 				return false;
 			uploads.add(connection);
 		}
+		return runConnectionInternal(connection, pool);
+	}
+
+	private boolean runConnectionInternal(final Uploader connection, ExecutorService pool) {
 		try {
 			pool.execute(new Runnable() {
 				@Override
 				public void run() {
-					potentialFinishTime.set(0);
 					boolean ret = connection.upload(sourceFile.getAbsolutePath());
 					synchronized (uploads) {
 						uploads.remove(connection);
 					}
-					if (ret && uploads.isEmpty()) {
+					if (ret && uploads.isEmpty() && potentialFinishTime.get() == 0) {
 						potentialFinishTime.set(System.currentTimeMillis());
 					}
 					lastActivityTime.set(System.currentTimeMillis());
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/SyncTransferHandler.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/SyncTransferHandler.java
index f7a9de85..27e11185 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/SyncTransferHandler.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/SyncTransferHandler.java
@@ -2,7 +2,10 @@ package org.openslx.bwlp.sat.fileserv;
 
 import java.io.File;
 import java.io.FileNotFoundException;
+import java.nio.ByteBuffer;
+import java.sql.SQLException;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ConcurrentHashMap;
@@ -10,17 +13,23 @@ import java.util.concurrent.TimeUnit;
 
 import org.apache.log4j.Logger;
 import org.apache.thrift.TException;
+import org.openslx.bwlp.sat.database.mappers.DbImage;
+import org.openslx.bwlp.sat.database.mappers.DbUser;
+import org.openslx.bwlp.sat.database.models.LocalImageVersion;
 import org.openslx.bwlp.sat.util.Constants;
+import org.openslx.bwlp.sat.util.FileSystem;
 import org.openslx.bwlp.sat.util.Formatter;
-import org.openslx.bwlp.sat.util.GrowingThreadPoolExecutor;
 import org.openslx.bwlp.sat.util.PrioThreadFactory;
+import org.openslx.bwlp.thrift.iface.ImageDetailsRead;
 import org.openslx.bwlp.thrift.iface.ImagePublishData;
 import org.openslx.bwlp.thrift.iface.InvocationError;
 import org.openslx.bwlp.thrift.iface.TAuthorizationException;
 import org.openslx.bwlp.thrift.iface.TInvocationException;
 import org.openslx.bwlp.thrift.iface.TNotFoundException;
+import org.openslx.bwlp.thrift.iface.TTransferRejectedException;
 import org.openslx.bwlp.thrift.iface.TransferInformation;
 import org.openslx.thrifthelper.ThriftManager;
+import org.openslx.util.GrowingThreadPoolExecutor;
 import org.openslx.util.QuickTimer;
 import org.openslx.util.QuickTimer.Task;
 
@@ -50,20 +59,31 @@ public class SyncTransferHandler {
 		private final Runnable worker = new Runnable() {
 			@Override
 			public void run() {
-				for (IncomingDataTransfer download : downloads.values()) {
+				final long now = System.currentTimeMillis();
+				for (Iterator<IncomingDataTransfer> it = downloads.values().iterator(); it.hasNext();) {
+					IncomingDataTransfer download = it.next();
 					if (download.isActive())
 						download.heartBeat(transferPool);
+					if (download.isComplete(now)) {
+						LOGGER.info("Download from master server complete");
+						it.remove();
+					}
 				}
-				for (OutgoingDataTransfer upload : uploads.values()) {
+				for (Iterator<OutgoingDataTransfer> it = uploads.values().iterator(); it.hasNext();) {
+					OutgoingDataTransfer upload = it.next();
 					if (upload.isActive())
 						upload.heartBeat(transferPool);
+					if (upload.isComplete(now)) {
+						LOGGER.info("Upload to master server complete");
+						it.remove();
+					}
 				}
 			}
 		};
 
 		@Override
 		public void fire() {
-			if (transferPool.getMaximumPoolSize() - transferPool.getActiveCount() < 1)
+			if (transferPool.getMaximumPoolSize() - transferPool.getActiveCount() < 2)
 				return;
 			transferPool.execute(worker);
 		}
@@ -75,18 +95,77 @@ public class SyncTransferHandler {
 		QuickTimer.scheduleAtFixedDelay(heartBeatTask, 123, TimeUnit.SECONDS.toMillis(56));
 	}
 
-	public synchronized static String requestImageDownload(ImagePublishData image)
+	public synchronized static String requestImageUpload(String userToken, LocalImageVersion img)
+			throws SQLException, TNotFoundException, TInvocationException, TAuthorizationException,
+			TTransferRejectedException {
+		TransferInformation transferInfo;
+		OutgoingDataTransfer existing = uploads.get(img.imageVersionId);
+		if (existing != null)
+			return existing.getId();
+		File absFile = FileSystem.composeAbsoluteImagePath(img);
+		if (!absFile.isFile() || !absFile.canRead()) {
+			LOGGER.error("Cannot upload " + img.imageVersionId + ": file missing: "
+					+ absFile.getAbsolutePath());
+			throw new TInvocationException(InvocationError.INTERNAL_SERVER_ERROR, "Source file not readable");
+		}
+		if (absFile.length() != img.fileSize) {
+			LOGGER.error("Cannot upload" + img.imageVersionId + ": wrong file size - expected "
+					+ img.fileSize + ", got " + absFile.length());
+			throw new TInvocationException(InvocationError.INTERNAL_SERVER_ERROR,
+					"File corrupted on satellite server");
+		}
+		checkUploadCount();
+		ImageDetailsRead details = DbImage.getImageDetails(null, img.imageBaseId);
+		List<ByteBuffer> blockHashes = DbImage.getBlockHashes(img.imageVersionId);
+		ImagePublishData publishData = new ImagePublishData();
+		publishData.createTime = img.createTime;
+		publishData.description = details.description;
+		publishData.fileSize = img.fileSize;
+		publishData.imageBaseId = img.imageBaseId;
+		publishData.imageName = details.imageName;
+		publishData.imageVersionId = img.imageVersionId;
+		publishData.isTemplate = details.isTemplate;
+		publishData.osId = details.osId;
+		publishData.user = DbUser.getOrNull(img.uploaderId);
+		publishData.virtId = details.virtId;
+		try {
+			transferInfo = ThriftManager.getMasterClient().submitImage(userToken, publishData, blockHashes);
+		} catch (TAuthorizationException e) {
+			LOGGER.warn("Master server rejected our session on uploadImage", e);
+			throw e;
+		} catch (TInvocationException e) {
+			LOGGER.warn("Master server made a boo-boo on uploadImage", e);
+			throw e;
+		} catch (TTransferRejectedException e) {
+			LOGGER.warn("Master server rejected our upload request", e);
+			throw e;
+		} catch (TException e) {
+			LOGGER.warn("Unknown exception on uploadImage to master server", e);
+			throw new TInvocationException(InvocationError.INTERNAL_SERVER_ERROR,
+					"Communication with master server failed");
+		}
+		OutgoingDataTransfer transfer = new OutgoingDataTransfer(transferInfo, absFile);
+		uploads.put(transfer.getId(), transfer);
+		transfer.heartBeat(transferPool);
+		return transfer.getId();
+	}
+
+	public synchronized static String requestImageDownload(String userToken, ImagePublishData image)
 			throws TInvocationException, TAuthorizationException, TNotFoundException {
 		TransferInformation transferInfo;
 		// Already replicating this one?
-		if (downloads.containsKey(image.imageVersionId))
-			return image.imageVersionId;
+		IncomingDataTransfer existing = downloads.get(image.imageVersionId);
+		if (existing != null)
+			return existing.getId();
 		checkDownloadCount();
 		try {
-			transferInfo = ThriftManager.getMasterClient().downloadImage(null, image.imageVersionId);
+			transferInfo = ThriftManager.getMasterClient().downloadImage(userToken, image.imageVersionId);
 		} catch (TAuthorizationException e) {
 			LOGGER.warn("Master server rejected our session on downloadImage", e);
 			throw e;
+		} catch (TInvocationException e) {
+			LOGGER.warn("Master server made a boo-boo on downloadImage", e);
+			throw e;
 		} catch (TNotFoundException e) {
 			LOGGER.warn("Master server couldn't find image on downloadImage", e);
 			throw e;
@@ -131,6 +210,26 @@ public class SyncTransferHandler {
 		}
 	}
 
+	private static void checkUploadCount() throws TInvocationException {
+		Iterator<OutgoingDataTransfer> it = uploads.values().iterator();
+		final long now = System.currentTimeMillis();
+		int activeUploads = 0;
+		while (it.hasNext()) {
+			OutgoingDataTransfer download = it.next();
+			if (download.isComplete(now) || download.hasReachedIdleTimeout(now)) {
+				download.cancel();
+				it.remove();
+				continue;
+			}
+			activeUploads++;
+		}
+		if (activeUploads > Constants.MAX_MASTER_UPLOADS) {
+			throw new TInvocationException(InvocationError.INTERNAL_SERVER_ERROR,
+					"Server busy. Too many running uploads (" + activeUploads + "/"
+							+ Constants.MAX_MASTER_UPLOADS + ").");
+		}
+	}
+
 	/**
 	 * Get an upload instance by given token.
 	 * 
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/mail/Mail.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/mail/Mail.java
index 72271b57..1d232a57 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/mail/Mail.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/mail/Mail.java
@@ -4,6 +4,7 @@ import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 
+import org.apache.commons.codec.binary.Hex;
 import org.openslx.bwlp.thrift.iface.UserInfo;
 
 public class Mail {
@@ -38,7 +39,7 @@ public class Mail {
 		synchronized (md) {
 			md.update(recipient.userId.getBytes(StandardCharsets.UTF_8));
 			md.update(message.getBytes(StandardCharsets.UTF_8));
-			return new String(md.digest(), StandardCharsets.US_ASCII);
+			return Hex.encodeHexString(md.digest());
 		}
 	}
 
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ServerHandler.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ServerHandler.java
index 0ea9921d..2d3d2b91 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ServerHandler.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ServerHandler.java
@@ -67,6 +67,7 @@ import org.openslx.bwlp.thrift.iface.Virtualizer;
 import org.openslx.bwlp.thrift.iface.WhoamiInfo;
 import org.openslx.sat.thrift.version.Version;
 import org.openslx.thrifthelper.ThriftManager;
+import org.openslx.util.ThriftUtil;
 
 public class ServerHandler implements SatelliteServer.Iface {
 
@@ -515,7 +516,7 @@ public class ServerHandler implements SatelliteServer.Iface {
 			throw new TInvocationException(InvocationError.INTERNAL_SERVER_ERROR,
 					"Could not write to local DB");
 		}
-		return SyncTransferHandler.requestImageDownload(imagePublishData);
+		return SyncTransferHandler.requestImageDownload(userToken, imagePublishData);
 	}
 
 	@Override
@@ -579,6 +580,27 @@ public class ServerHandler implements SatelliteServer.Iface {
 	@Override
 	public LectureRead getLectureDetails(String userToken, String lectureId) throws TAuthorizationException,
 			TNotFoundException, TInvocationException {
+		//
+		// TEST
+		//
+		/*
+		String imageVersionId = "e9de1941-b673-4711-b033-d8c37d1e2d3e";
+		LocalImageVersion img;
+		try {
+			img = DbImage.getLocalImageData(imageVersionId);
+			SyncTransferHandler.requestImageUpload(userToken, img);
+		} catch (SQLException e1) {
+			// TODO Auto-generated catch block
+			e1.printStackTrace();
+		} catch (TTransferRejectedException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+		*/
+		//
+		//
+		//
+		//
 		UserInfo user = SessionManager.getOrFail(userToken);
 		User.canSeeLectureDetailsOrFail(user);
 		try {
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ThriftUtil.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ThriftUtil.java
deleted file mode 100644
index ee02f440..00000000
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/thrift/ThriftUtil.java
+++ /dev/null
@@ -1,30 +0,0 @@
-package org.openslx.bwlp.sat.thrift;
-
-import java.nio.ByteBuffer;
-import java.util.ArrayList;
-import java.util.List;
-
-public class ThriftUtil {
-
-	public static List<byte[]> unwrapByteBufferList(List<ByteBuffer> blockHashes) {
-		if (blockHashes == null || blockHashes.isEmpty())
-			return null;
-		List<byte[]> hashList = new ArrayList<>(blockHashes.size());
-		for (ByteBuffer hash : blockHashes) {
-			byte[] buffer = new byte[hash.remaining()];
-			hash.get(buffer);
-			hashList.add(buffer);
-		}
-		return hashList;
-	}
-
-	public static byte[] unwrapByteBuffer(ByteBuffer buffer) {
-		byte[] byteArray = null;
-		if (buffer != null) {
-			byteArray = new byte[buffer.remaining()];
-			buffer.get(byteArray);
-		}
-		return byteArray;
-	}
-
-}
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Configuration.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Configuration.java
index 5dd9b8ec..f2926d64 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Configuration.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Configuration.java
@@ -4,8 +4,12 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
 import java.util.Properties;
 
+import javax.net.ssl.SSLContext;
+
 import org.apache.log4j.Logger;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
@@ -24,6 +28,7 @@ public class Configuration {
 	private static boolean masterSsl = true;
 	private static int masterPort = 9091;
 	private static String dbLocationTable;
+	private static SSLContext ctx = null;
 
 	public static boolean load() throws IOException {
 		// Load configuration from java properties file
@@ -77,7 +82,7 @@ public class Configuration {
 	public static String getDbPassword() {
 		return dbPassword;
 	}
-	
+
 	public static String getDbLocationTable() {
 		return dbLocationTable;
 	}
@@ -104,4 +109,19 @@ public class Configuration {
 		return new File(vmStoreProdPath, subdirDate.print(System.currentTimeMillis()));
 	}
 
+	public static SSLContext getMasterServerSslContext() throws NoSuchAlgorithmException,
+			KeyManagementException {
+		if (!getMasterServerSsl())
+			throw new RuntimeException("SSL not activated");
+		if (ctx == null) {
+			synchronized (LOGGER) {
+				if (ctx == null) {
+					ctx = SSLContext.getInstance("TLSv1.2");
+					ctx.init(null, null, null);
+				}
+			}
+		}
+		return ctx;
+	}
+
 }
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/GrowingThreadPoolExecutor.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/GrowingThreadPoolExecutor.java
deleted file mode 100644
index a7265199..00000000
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/GrowingThreadPoolExecutor.java
+++ /dev/null
@@ -1,85 +0,0 @@
-package org.openslx.bwlp.sat.util;
-
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.Executors;
-import java.util.concurrent.RejectedExecutionHandler;
-import java.util.concurrent.ThreadFactory;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
-
-/**
- * Grows to maximum pool size before queueing. See
- * http://stackoverflow.com/a/20153234/2043481
- */
-public class GrowingThreadPoolExecutor extends ThreadPoolExecutor {
-	private int userSpecifiedCorePoolSize;
-	private int taskCount;
-	
-    /**
-     * The default rejected execution handler
-     */
-    private static final RejectedExecutionHandler defaultHandler =
-        new AbortPolicy();
-
-	public GrowingThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
-			TimeUnit unit, BlockingQueue<Runnable> workQueue) {
-		this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, defaultHandler);
-	}
-	
-	public GrowingThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
-			BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory) {
-		this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, defaultHandler);
-	}
-
-	public GrowingThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
-			BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler) {
-		this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, Executors.defaultThreadFactory(),
-				handler);
-	}
-	
-	public GrowingThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
-			BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) {
-		super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler);
-		userSpecifiedCorePoolSize = corePoolSize;
-	}
-
-	@Override
-	public void execute(Runnable runnable) {
-		synchronized (this) {
-			taskCount++;
-			setCorePoolSizeToTaskCountWithinBounds();
-		}
-		super.execute(runnable);
-	}
-
-	@Override
-	protected void afterExecute(Runnable runnable, Throwable throwable) {
-		super.afterExecute(runnable, throwable);
-		synchronized (this) {
-			taskCount--;
-			setCorePoolSizeToTaskCountWithinBounds();
-		}
-	}
-
-	private void setCorePoolSizeToTaskCountWithinBounds() {
-		int threads = taskCount;
-		if (threads < userSpecifiedCorePoolSize)
-			threads = userSpecifiedCorePoolSize;
-		if (threads > getMaximumPoolSize())
-			threads = getMaximumPoolSize();
-		super.setCorePoolSize(threads);
-	}
-	
-	public void setCorePoolSize(int corePoolSize) {
-		synchronized (this) {
-			userSpecifiedCorePoolSize = corePoolSize;
-		}
-	}
-	
-	@Override
-	public int getCorePoolSize() {
-		synchronized (this) {
-			return userSpecifiedCorePoolSize;
-		}
-	}
-}
\ No newline at end of file
diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Util.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Util.java
index 53bfa403..8e6950e8 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Util.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/util/Util.java
@@ -1,6 +1,5 @@
 package org.openslx.bwlp.sat.util;
 
-import java.io.Closeable;
 import java.util.regex.Pattern;
 
 public class Util {
@@ -9,25 +8,6 @@ public class Util {
 	 * Try to close everything passed to this method. Never throw an exception
 	 * if it fails, just silently continue.
 	 * 
-	 * @param item One or more objects that are Closeable
-	 */
-	public static void safeClose(Closeable... item) {
-		if (item == null)
-			return;
-		for (Closeable c : item) {
-			if (c == null)
-				continue;
-			try {
-				c.close();
-			} catch (Exception e) {
-			}
-		}
-	}
-
-	/**
-	 * Try to close everything passed to this method. Never throw an exception
-	 * if it fails, just silently continue.
-	 * 
 	 * @param item One or more objects that are AutoCloseable
 	 */
 	public static void safeClose(AutoCloseable... item) {