/*
* JBoss, Home of Professional Open Source
* Copyright 2008-9, Red Hat Middleware LLC, and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
* @authors Andrew Dinn
*/
package org.jboss.byteman.agent;
import java.lang.instrument.Instrumentation;
import java.lang.instrument.ClassFileTransformer;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.jar.JarFile;
import java.util.ArrayList;
import java.util.List;
import java.io.File;
import java.io.IOException;
import java.io.FileInputStream;
import java.net.Socket;
/**
* agent class supplied at JVM startup to install byteman package bytecode transformer
*/
public class Main {
public static boolean firstTime = true;
public final static String BYTEMAN_PREFIX = "org.jboss.byteman.";
public static void premain(String args, Instrumentation inst)
throws Exception
{
// guard against the agent being loaded twice
synchronized (Main.class) {
if (firstTime) {
firstTime = false;
} else {
throw new Exception("Main : attempting to load Byteman agent more than once");
}
}
boolean allowRedefine = false;
if (args != null) {
// args are supplied eparated by ',' characters
String[] argsArray = args.split(",");
// we accept extra jar files to be added to the boot/sys classpaths
// script files to be scanned for rules
// listener flag which implies use of a retransformer
for (String arg : argsArray) {
if (arg.startsWith(BOOT_PREFIX)) {
bootJarPaths.add(arg.substring(BOOT_PREFIX.length(), arg.length()));
} else if (arg.startsWith(SYS_PREFIX)) {
sysJarPaths.add(arg.substring(SYS_PREFIX.length(), arg.length()));
} else if (arg.startsWith(ADDRESS_PREFIX)) {
hostname = arg.substring(ADDRESS_PREFIX.length(), arg.length());
} else if (arg.startsWith(PORT_PREFIX)) {
try {
port = Integer.valueOf(arg.substring(PORT_PREFIX.length(), arg.length()));
} catch (Exception e) {
System.err.println("Invalid port specified [" + arg + "]. Cause: " + e);
}
} else if (arg.startsWith(SCRIPT_PREFIX)) {
scriptPaths.add(arg.substring(SCRIPT_PREFIX.length(), arg.length()));
} else if (arg.startsWith(LISTENER_PREFIX)) {
String value = arg.substring(LISTENER_PREFIX.length(), arg.length());
allowRedefine = Boolean.parseBoolean(value);
} else if (arg.startsWith(REDEFINE_PREFIX)) {
// this is only for backwards compatibility -- it is the same as listener
String value = arg.substring(REDEFINE_PREFIX.length(), arg.length());
allowRedefine = Boolean.parseBoolean(value);
} else if (arg.startsWith(PROP_PREFIX)) {
// this can be used to set byteman properties
String prop = arg.substring(PROP_PREFIX.length(), arg.length());
String value="";
if (prop.startsWith(BYTEMAN_PREFIX)) {
int index = prop.indexOf('=');
if (index > 0) {
// need to split off the value
if (index == prop.length() - 1)
{
// value is empty so just drop the =
prop = prop.substring(0, index);
} else {
value = prop.substring(index + 1);
prop = prop.substring(0, index);
}
}
System.out.println("Setting " + prop + "=" + value);
System.setProperty(prop, value);
} else {
System.err.println("Invalid property : " + prop);
}
} else {
System.err.println("org.jboss.byteman.agent.Main:\n" +
" illegal agent argument : " + arg + "\n" +
" valid arguments are boot:<path-to-jar>, sys:<path-to-jar>, script:<path-to-script> or listener:<true-or-false>");
}
}
}
// add any boot jars to the boot class path
for (String bootJarPath : bootJarPaths) {
try {
JarFile jarfile = new JarFile(new File(bootJarPath));
inst.appendToBootstrapClassLoaderSearch(jarfile);
} catch (IOException ioe) {
System.err.println("org.jboss.byteman.agent.Main: unable to open boot jar file : " + bootJarPath);
throw ioe;
}
}
// add any sys jars to the system class path
for (String sysJarPath : sysJarPaths) {
try {
JarFile jarfile = new JarFile(new File(sysJarPath));
inst.appendToSystemClassLoaderSearch(jarfile);
} catch (IOException ioe) {
System.err.println("org.jboss.byteman.agent.Main: unable to open system jar file : " + sysJarPath);
throw ioe;
}
}
// create a socket so we can be sure it is loaded before the transformer gets cerated. otherwise
// we seem to hit a deadlock when trying to instrument socket
Socket dummy = new Socket();
// look up rules in any script files
for (String scriptPath : scriptPaths) {
try {
FileInputStream fis = new FileInputStream(scriptPath);
byte[] bytes = new byte[fis.available()];
fis.read(bytes);
String ruleScript = new String(bytes);
scripts.add(ruleScript);
} catch (IOException ioe) {
System.err.println("org.jboss.byteman.agent.Main: unable to read rule script file : " + scriptPath);
throw ioe;
}
}
// install an instance of Transformer to instrument the bytecode
// n.b. this is done with boxing gloves on using explicit class loading and method invocation
// via reflection for a GOOD reason. This class (Main) gets laoded by the System class loader.
// If we refer to Transformer by name then it also gets loaded va the System class loader.
// But if we want to transform a bootstrap class we need Transformer (et al) to be visible
// from the bootstrap class loader. That will not happen until after this method has called
// inst.appendToBootstrapClassLoaderSearch (see above) to add the byteman jar to the path.
// Directly referring to Transformer will giveus two versions of Transformer et al. Not only
// does that cause us class mismathc problem it also means that a new done here will not install
// the new instance in the static field fo the oneloaded in the bootstrap loader. If instead we
// use boxing gloves then the byteman code wil get loaded in the bootstrap loader and its constructor
// will be called.
//
// Of course, if the user does not supply boot:byteman.jar as a -javaagent option then class references
// resolve against the system loader and injection into bootstrap classes fails. But that's still ok
// because the byteman classes are still only foudn in one place.
boolean isRedefine = inst.isRedefineClassesSupported();
ClassFileTransformer transformer;
ClassLoader loader = ClassLoader.getSystemClassLoader();
Class transformerClazz;
if (allowRedefine && isRedefine) {
transformerClazz = loader.loadClass("org.jboss.byteman.agent.Retransformer");
//transformer = new Retransformer(inst, scriptPaths, scripts, true);
Constructor constructor = transformerClazz.getConstructor(Instrumentation.class, List.class, List.class, boolean.class);
transformer = (ClassFileTransformer)constructor.newInstance(new Object[] { inst, scriptPaths, scripts, isRedefine});
} else {
transformerClazz = loader.loadClass("org.jboss.byteman.agent.Transformer");
//transformer = new Transformer(inst, scriptPaths, scripts, isRedefine);
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", String.class, Integer.class);
method.invoke(transformer, hostname, port);
}
if (isRedefine) {
Method method;
method = transformerClazz.getMethod("installBootScripts");
method.invoke(transformer);
//transformer.installBootScripts();
}
}
public static void agentmain(String args, Instrumentation inst) throws Exception
{
premain(args, inst);
}
/**
* prefix used to specify port argument for agent
*/
private static final String PORT_PREFIX = "port:";
/**
* prefix used to specify bind address argument for agent
*/
private static final String ADDRESS_PREFIX = "address:";
/**
* prefix used to specify boot jar argument for agent
*/
private static final String BOOT_PREFIX = "boot:";
/**
* prefix used to specify system jar argument for agent
*/
private static final String SYS_PREFIX = "sys:";
/**
* prefix used to specify script argument for agent
*/
private static final String SCRIPT_PREFIX = "script:";
/**
* prefix used to specify transformer type argument for agent
*/
private static final String LISTENER_PREFIX = "listener:";
/**
* for backwards compatibiltiy
*/
private static final String REDEFINE_PREFIX = "redefine:";
/**
* prefix used to specify system properties to be set before starting the agent
*/
private static final String PROP_PREFIX = "prop:";
/**
* list of paths to extra bootstrap jars supplied on command line
*/
private static List<String> bootJarPaths = new ArrayList<String>();
/**
* list of paths to extra system jars supplied on command line
*/
private static List<String> sysJarPaths = new ArrayList<String>();
/**
* list of paths to script files supplied on command line
*/
private static List<String> scriptPaths = new ArrayList<String>();
/**
* list of scripts read from script files
*/
private static List<String> scripts = new ArrayList<String>();
/**
* The hostname to bind the listener to, supplied on the command line (optional argument)
*/
private static String hostname = null;
/**
* The port that the listener will listen to, supplied on the command line (optional argument)
*/
private static Integer port = null;
}