I worked around this problem by copying the source from Main.java, importing some stock Byteman classes, and having it run my custom class based off of TransformListener.java that I can use to load new rules in anyway that I want to.

AgentMain.java

...... Imports omitted

import org.jboss.byteman.agent.Retransformer;

public class AgentMain {

   private static ScriptReload scriptReload;

...... lines omitted

    public static void premain(String args, Instrumentation inst) {

      ...... lines omitted

       if (allowRedefine && isRedefine) {
          scriptReload.initialize((Retransformer)transformer); 
          /*
          *     transformerClazz = loader.loadClass("org.jboss.byteman.agent.Retransformer");     
          *     Method method = transformerClazz.getMethod("initialize", Retransformer.class);     
          *     method.invoke((Retransformer)transformer);     
          */ 
        }

...... lines omitted

}

ScriptReload.java

import org.jboss.byteman.agent.Retransformer;
import org.jboss.byteman.agent.Transformer;

public class ScriptReload extends Thread {
  private static ScriptReload scriptReload = null;
  private Retransformer retransformer;
  private static List<String> scriptTexts;
  private static List<String> scriptNames;

  ScriptReload(Retransformer retransformer) {
      this.retransformer = retransformer;
      setDaemon(true);
  }

  public void run() {
      scriptTexts = Arrays.asList("RULE jabber\nCLASS java.lang.Thread\nMETHOD start()\nIF true\nDO traceln(\"*** start for thread: \"+ $0.getName())\nENDRULE\n");
      scriptNames = Arrays.asList("newRules.btm");

      PrintStream stdout = System.out;
      System.setOut(stdout);
      PrintWriter printWriter = new PrintWriter(stdout);

      while (true) {
          try {
              Thread.sleep(5000);
              /*
               * Get new script however you want
               */
              System.out.printf("Installing Scripts %s\n", scriptNames.toString());
              retransformer.installScript(scriptTexts, scriptNames, printWriter);
          } catch(InterruptedException e) {
              e.printStackTrace();
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  }
  public static synchronized boolean initialize(Retransformer retransformer) {
      if(scriptReload == null) {
          scriptReload = new ScriptReload(retransformer);
          scriptReload.start();
      }
  return true;
  }

This is a rudementry example where the new rule to add is hardcoded, but I plan to add logic to add rules, purge rules, add jars, and other logic such as in the TransformListener. 

This example is just to show that you can write your own way to reload rules without having to fork Byteman.

Andrew, Thanks for the reply!

I will try and changed it to only use reflection in the Main class and post my changes,

hopefully you can take a look and let me know if you see any other problem areas.

Alright, I managed to remove all of the imports of Byteman Classes from the Main class.

The way I decided to do it was to reuse most of the code from Retranformer class, changing only the addTransformListener method to use my ScriptReload class.

I also created a Gist with the omitted lines: https://gist.github.com/4be0097ed91ca23b315a.git.

Feedback is always appreciated!

AgentMain.java

package com.example.proj.agent;
... imports omitted
public class AgentMain {
    ... lines omitted
    public static void premain(String args, Instrumentation inst) {
        ... lines omitted

        if (allowRedefine && isRedefine) {
           transformerClazz = loader.loadClass("com.example.proj.agent.AgentRetransformer");
           Constructor constructor.newInstance(new Object[] { inst, scriptPaths, scripts, isRedefine});
        } else {
            transformerClazz = loader.loadClass("org.jboss.byteman.agent.Transformer");
            Constructor constructor = transformerClazz.getConstructor(Instrumentation.class, List.class, List.class, boolean.class);
            transformer = (ClassFileTransformer)constructor.newInstance(new Object[] { inst, scriptPaths, scripts, isRedefine});
        }
        inst.addTransformer(transformer, true);
     
        if (allowRedefine && isRedefine) {
            Method method = transformerClazz.getMethod("addTransformListener");
            method.invoke(transformer);
        }
        ... lines omitted

   }
    ... lines omitted

}
}

AgentRetransformer.java

package com.example.proj.agent;

... imports omitted

import org.jboss.byteman.agent.RuleScript;
import org.jboss.byteman.agent.ScriptRepository;
import org.jboss.byteman.agent.Transform;
import org.jboss.byteman.agent.Transformer;

public class AgentRetransformer extends Transformer {
    ... lines omitted

    public AgentRetransformer(Instrumentation inst, List<String> scriptPaths, List<String> scriptTexts, boolean isRedefine)
            throws Exception
    {
        super(inst, scriptPaths, scriptTexts, isRedefine);
    }

    ... lines omitted

    public void addTransformListener()
    {
        ScriptReload.initialize(this);
    }

    ... lines omitted

}

ScriptReload.java

package com.example.proj.agent;

import org.jboss.byteman.agent.Retransformer;
import org.jboss.byteman.agent.Transformer;

public class ScriptReload extends Thread {
  private static ScriptReload scriptReload = null;
  private Retransformer retransformer;
  private static List<String> scriptTexts;
  private static List<String> scriptNames;

  ScriptReload(Retransformer retransformer) {
      this.retransformer = retransformer;
      setDaemon(true);
  }

  public void run() {
      scriptTexts = Arrays.asList("RULE jabber\nCLASS java.lang.Thread\nMETHOD start()\nIF true\nDO traceln(\"*** start for thread: \"+ $0.getName())\nENDRULE\n");
      scriptNames = Arrays.asList("newRules.btm");

      PrintStream stdout = System.out;
      System.setOut(stdout);
      PrintWriter printWriter = new PrintWriter(stdout);

      while (true) {
          try {
              Thread.sleep(5000);
              /*
               * Get new script however you want
               */
              System.out.printf("Installing Scripts %s\n", scriptNames.toString());
              retransformer.installScript(scriptTexts, scriptNames, printWriter);
          } catch(InterruptedException e) {
              e.printStackTrace();
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  }
  public static synchronized boolean initialize(Retransformer retransformer) {
      if(scriptReload == null) {
          scriptReload = new ScriptReload(retransformer);
          scriptReload.start();
      }
  return true;
  }

Hey Andrew,

I made the changes you suggested, inheriting the behavior from Retransformer is an obvious improvement.

Do you have any suggestions on the best way for me to add the new code snippets to maximize the usefulness of this discussion for other community members?

I am glad you brought up the decoupling of the retransformer and socket-listener specific functions because that was my next question.

I would volunteer to work on it now, but I need to talk to my companies law department before I can take on any work in an official capacity.

Ideally, I would much rather contribute then spend my time on a work-around!

My suggestion would be to keep your socket-listener as a default from the Java agent listener param (e.g. listener=true ), but possibly allowing the path to a jar in the Java agent listener param as a replacement for your socket-listener (e.g. listener=%CUSTOM_LISTENER_HOME%/File-Listener.jar ) that can be parsed out.

Some use cases off the top of my head.

• Rules can be loaded from any source
• Custom security implementations can be used to fit individual needs
• No longer relies on ports
• Makes it possible to negate the threat of a malicious insider

Hopefully by letting developers code their own listeners you can spend more time on the Byteman core functionality we all love so much!

Let me know your thoughts on the matter and I will update you when I hear back from the law department about contributing to the project.

Thanks for all your great feedback!

David McElligott