Allow SASL UID to be provided via the TransportBuilder

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/SASL.java

@@ -26,6 +26,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.OptionalLong;
 import java.util.Random;
 
 import org.freedesktop.dbus.connections.transports.AbstractTransport;
@@ -422,17 +423,18 @@ public String[] getTypes(int _types) {
      * @param _mode mode
      * @param _types types
      * @param _guid guid
+     * @param _saslUid SASL UID
      * @param _sock socket channel
      * @param _transport transport
      *
      * @return true if the auth was successful and false if it failed.
      * @throws IOException on failure
      */
-    public boolean auth(SaslMode _mode, int _types, String _guid, SocketChannel _sock, AbstractTransport _transport) throws IOException {
+    public boolean auth(SaslMode _mode, int _types, String _guid, OptionalLong _saslUid, SocketChannel _sock, AbstractTransport _transport) throws IOException {
         String luid = null;
         String kernelUid = null;
 
-        long uid = getUserId();
+        long uid = _saslUid.orElse(getUserId());
         luid = stupidlyEncode("" + uid);
 
         SASL.Command c;

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/config/TransportConfig.java

@@ -6,6 +6,7 @@
 import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Objects;
+import java.util.OptionalLong;
 import java.util.Set;
 import java.util.function.Consumer;
 
@@ -29,6 +30,7 @@ public final class TransportConfig {
     private int                         timeout          = 10000;
     private boolean                     autoConnect      = true;
     private SaslAuthMode                authMode         = null;
+    private OptionalLong                saslUid          = OptionalLong.empty();
 
     /** user to set on socket file if this is a server transport (null to do nothing). */
     private String                      fileOwner;
@@ -94,7 +96,15 @@ public void setTimeout(int _timeout) {
         timeout = _timeout;
     }
 
-    public SaslAuthMode getAuthMode() {
+    public OptionalLong getSaslUid() {
+		return saslUid;
+	}
+
+	public void setSaslUid(OptionalLong _saslUid) {
+		this.saslUid = _saslUid;
+	}
+
+	public SaslAuthMode getAuthMode() {
         return authMode;
     }
 

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/config/TransportConfigBuilder.java

@@ -2,6 +2,7 @@
 
 import java.nio.file.attribute.PosixFilePermission;
 import java.util.Objects;
+import java.util.OptionalLong;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -142,6 +143,20 @@ public X withTimeout(int _timeout) {
         return self();
     }
 
+    /**
+     * Set to UID to present during SASL authentication.
+     * <p>
+     * Default is the user of the running JVM process on Unix-like operating systems. On Windows, the default is zero.<br><br>
+     *
+     * @param _saslUid UID to set, if -1 is given default is used
+     *
+     * @return this
+     */
+    public X withSaslUid(long _saslUid) {
+        config.setSaslUid(_saslUid == -1 ? OptionalLong.empty() : OptionalLong.of(_saslUid));
+        return self();
+    }
+
     /**
      * The owner of the socket file if a unix socket is used and this is a server transport.
      * <p>

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/transports/AbstractTransport.java

@@ -3,6 +3,7 @@
 import java.io.Closeable;
 import java.io.IOException;
 import java.nio.channels.SocketChannel;
+import java.util.OptionalLong;
 import java.util.ServiceConfigurationError;
 import java.util.ServiceLoader;
 import java.util.function.Consumer;
@@ -34,6 +35,7 @@ public abstract class AbstractTransport implements Closeable {
     private final BusAddress                     address;
 
     private SASL.SaslMode                        saslMode;
+    private OptionalLong                         saslUid;
 
     private int                                  saslAuthMode;
     private IMessageReader                       inputReader;
@@ -155,7 +157,7 @@ public void setPreConnectCallback(Consumer<AbstractTransport> _run) {
     private void authenticate(SocketChannel _sock) throws IOException {
         SASL sasl = new SASL(hasFileDescriptorSupport());
         try {
-            if (!sasl.auth(saslMode, saslAuthMode, address.getGuid(), _sock, this)) {
+            if (!sasl.auth(saslMode, saslAuthMode, address.getGuid(), saslUid, _sock, this)) {
                 throw new AuthenticationException("Failed to authenticate");
             }
         } catch (IOException e) {
@@ -200,7 +202,15 @@ private void setInputOutput(SocketChannel _socket) {
 
     }
 
-    protected int getSaslAuthMode() {
+    protected OptionalLong getSaslUid() {
+		return saslUid;
+	}
+
+	protected void setSaslUid(OptionalLong saslUid) {
+		this.saslUid = saslUid;
+	}
+
+	protected int getSaslAuthMode() {
         return saslAuthMode;
     }
 

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/transports/TransportBuilder.java

@@ -324,6 +324,7 @@ public AbstractTransport build() throws DBusException, IOException {
             ((IFileBasedBusAddress) myBusAddress).updatePermissions(config.getFileOwner(), config.getFileGroup(), config.getFileUnixPermissions());
         }
 
+        transport.setSaslUid(config.getSaslUid());
         transport.setPreConnectCallback(config.getPreConnectCallback());
 
         if (config.isAutoConnect()) {