/*
* JBoss, Home of Professional Open Source
* Copyright 2009-10, Red Hat 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.
*
* (C) 2009-10,
* @authors Andrew Dinn
*/
package org.jboss.byteman.agent;
import org.jboss.byteman.agent.adapter.BMJSRInliner;
import org.jboss.byteman.agent.adapter.BMLocalScopeAdapter;
import org.jboss.byteman.agent.adapter.RuleCheckAdapter;
import org.jboss.byteman.agent.adapter.RuleTriggerAdapter;
import org.jboss.byteman.rule.exception.CompileException;
import org.jboss.byteman.rule.exception.ParseException;
import org.jboss.byteman.rule.exception.TypeException;
import org.jboss.byteman.rule.exception.TypeWarningException;
import org.jboss.byteman.rule.type.Type;
import org.jboss.byteman.rule.type.TypeHelper;
import org.jboss.byteman.rule.Rule;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Opcodes;
import java.util.HashMap;
import java.util.Iterator;
/**
* Class used to localise the context information employed when creating a rule from a rule script and
* using it to transform a method
*/
public class TransformContext
{
public TransformContext(RuleScript ruleScript, String triggerClassName, ClassLoader loader, HelperManager helperManager)
{
// the target method spec may just be a bare method name or it may optionally include a
// parameter type list and a return type. With Java syntax the return type appears before
// the method name. if so we modify the target method spec so that the return type appears
// after the argument list which means we also accept a spec supplied in this format. The
// parseMethodDescriptor call below will eat specs in this latter format.
final String targetMethodSpec = ruleScript.getTargetMethod();
String mungedMethodSpec = mungeMethodSpecReturnType(targetMethodSpec);
this.ruleScript = ruleScript;
this.triggerClassName = triggerClassName;
this.targetMethodName = TypeHelper.parseMethodName(mungedMethodSpec);
this.targetDescriptor = TypeHelper.parseMethodDescriptor(mungedMethodSpec);
this.loader = loader;
this.helperManager = helperManager;
this.ruleMap = new HashMap<String, Rule>();
this.firstRule = null;
}
public byte[] transform(byte[] targetClassBytes)
{
final Location handlerLocation = ruleScript.getTargetLocation();
String ruleName = ruleScript.getName();
try {
parseRule();
} catch (ParseException pe) {
if (Transformer.isVerbose()) {
System.out.println("org.jboss.byteman.agent.Transformer : error parsing rule " + ruleName + "\n" + pe);
}
recordFailedTransform(pe);
return targetClassBytes;
} catch (Throwable th) {
if (Transformer.isVerbose()) {
System.out.println("org.jboss.byteman.agent.Transformer : unexpected error parsing rule " + ruleName + "\n" + th);
}
recordFailedTransform(th);
return targetClassBytes;
}
// ok, we have a rule with a matching trigger class and a target method and location
// we need to see if the class has a matching trigger method/location and, if so, add a
// call to execute the rule when we hit the relevant line
// there may be more than one matching method. if so we need to associate a separate Rule
// instance with each transformed method because we bind the argument/local vars using types
// specific to that method
// we may have to ignore certain matches because they don't fit the type spec for
// the rule. if we can queue a type warning exception and carry on injecting other
// trigger locations then we do so. if not we throw a type exception and invalidate
// all injection for the trigger class. it would be better if we could just byapss
// a single injection point or just the injection points in the offending method
// but sometimes we can only back out by throwing an exception from within a bytecode
// visitor and th eonly safe ting to do is back out the whole transform.
ClassReader cr = new ClassReader(targetClassBytes);
// need to provide a real writer here so that labels get resolved
ClassWriter dummy = getNonLoadingClassWriter(0);
RuleCheckAdapter checkAdapter = handlerLocation.getRuleCheckAdapter(dummy, this);
try {
// insert a local scope adapter between the reader and the adapter so
// we see info about vars going in and out of scope
BMLocalScopeAdapter localScopeAdapter = new BMLocalScopeAdapter(checkAdapter);
cr.accept(localScopeAdapter, ClassReader.EXPAND_FRAMES);
} catch (TransformFailure te) {
// will already be notified
return targetClassBytes;
} catch (Throwable th) {
// hmm, unexpected error
if (Transformer.isVerbose()) {
System.out.println("org.jboss.byteman.agent.Transformer : unexpected error applying rule " + ruleScript.getName() + " to class " + triggerClassName + "\n" + th);
th.printStackTrace(System.out);
}
recordFailedTransform(th);
return targetClassBytes;
}
// only insert the rule trigger call if there is a suitable location in the target method
if (!checkAdapter.isVisited()) {
// there was no matching method so ignore
return targetClassBytes;
}
if (Transformer.isVerbose()) {
System.out.println("org.jboss.byteman.agent.Transformer : possible trigger for rule " + ruleScript.getName() + " in class " + triggerClassName);
}
cr = new ClassReader(targetClassBytes);
ClassWriter cw = getNonLoadingClassWriter(ClassWriter.COMPUTE_MAXS|ClassWriter.COMPUTE_FRAMES);
RuleTriggerAdapter adapter = handlerLocation.getRuleAdapter(cw, this);
// insert a JSR inliner between the reader and the adapter so we don't see JSR/RET sequences
// we use a specialised version which provides us with info about vars going in and out of scope
BMJSRInliner jsrInliner = new BMJSRInliner(adapter);
try {
cr.accept(jsrInliner, ClassReader.EXPAND_FRAMES);
} catch (TransformFailure te) {
// will already be notified
return targetClassBytes;
} catch (Throwable th) {
if (Transformer.isVerbose()) {
System.out.println("org.jboss.byteman.agent.Transformer : unexpected error injecting trigger for rule " + ruleScript.getName() + " into class " + triggerClassName + "\n" + th);
th.printStackTrace(System.out);
}
recordFailedTransform(th);
return targetClassBytes;
}
// hand back the transformed byte code
if (Transformer.isVerbose()) {
System.out.println("org.jboss.byteman.agent.Transformer : inserted trigger for " + ruleScript.getName() + " in class " + triggerClassName);
}
// record all successfully transformed rules
if (!notifyRules()) {
// rule must have been deleted so forget the transform
return targetClassBytes;
} else {
return cw.toByteArray();
}
}
public void parseRule() throws Exception {
Rule rule = Rule.create(ruleScript, loader, helperManager);
// stash this rule away under the class name so we can reuse it for the first matching method
ruleMap.put(triggerClassName, rule);
// keep a handle on the first rule
firstRule = rule;
}
/**
* called by a trigger adapter to find a rule specific to a given trigger method,
* expects to find a rule created by the corresponding check adapter. if no rule is
* found then injection must be bypassed for this method
* @param triggerMethodName
* @param triggerMethodDescriptor
* @return
*/
public Rule lookupRule(String triggerMethodName, String triggerMethodDescriptor)
{
String key = getRuleKey(triggerMethodName, triggerMethodDescriptor);
return ruleMap.get(key);
}
/**
* called by a check adapter to create a rule specific to a given trigger method.
* the first such call reuses the rule created by the intiial parse. subsequent calls
* create a new rule.
* @param triggerMethodName
* @param triggerMethodDescriptor
* @return
*/
public Rule createRule(String triggerMethodName, String triggerMethodDescriptor)
{
String key = getRuleKey(triggerMethodName, triggerMethodDescriptor);
// use the initially parsed rule if we can otherwise create one
Rule rule = ruleMap.remove(triggerClassName);
if (rule == null) {
try {
rule = Rule.create(ruleScript, loader, helperManager);
} catch(Throwable th) {
// will not happen
}
}
ruleMap.put(key, rule);
return rule;
}
/**
* called by a check adapter to warn that a transform was not possible for a potential match
* target. this inhibits injection into the method being warned about allowing other injection
* operations to continue.
* @param warningMessage
*/
public void warn(String triggerMethodName, String triggerMethodDescriptor, String warningMessage)
{
// remove the rule so that we don't try to inject into this method
String key = getRuleKey(triggerMethodName, triggerMethodDescriptor);
Rule rule = ruleMap.remove(key);
// now attach an exception to the rule script
String message = warningMessage + " for method " + triggerMethodName + TypeHelper.internalizeDescriptor(triggerMethodDescriptor);
TypeWarningException tw = new TypeWarningException(message);
ruleScript.recordTransform(loader, triggerClassName, triggerMethodName, triggerMethodDescriptor, rule, tw);
}
/**
* called by a check or trigger adapter to fail a transform because of a type issue. this aborts all
* injection into the current class not just injection into the current method.
* @param failMessage
* @param triggerMethodName
* @param triggerMethodDescriptor
*/
public void fail(String failMessage, String triggerMethodName, String triggerMethodDescriptor)
{
String key = getRuleKey(triggerMethodName, triggerMethodDescriptor);
Rule rule = ruleMap.get(key);
String message = failMessage + " for method " + triggerMethodName + TypeHelper.internalizeDescriptor(triggerMethodDescriptor);
TypeException te = new TypeException(message);
ruleScript.recordTransform(loader, triggerClassName, triggerMethodName, triggerMethodDescriptor, rule, te);
purgeRules();
throw new TransformFailure();
}
public void recordFailedTransform(Throwable th)
{
ruleScript.recordTransform(loader, triggerClassName, null, null, null, th);
purgeRules();
}
public boolean matchTargetMethod(int access, String name, String desc)
{
return ((access & (Opcodes.ACC_NATIVE|Opcodes.ACC_ABSTRACT|Opcodes.ACC_SYNTHETIC)) == 0 &&
targetMethodName.equals(name) &&
(targetDescriptor.equals("") || TypeHelper.equalDescriptors(targetDescriptor, desc)));
}
public boolean injectIntoMethod(String name, String desc)
{
return lookupRule(name, desc) != null;
}
public String getTriggerClassName()
{
return triggerClassName;
}
/**
* private exception class used to throw our way out of the ASM adapter code back into the transform
* method at the top level. we have to use a RuntimeException for this as we cannot change the ASm
* API to allow opther exception types to be plumbed through the code
*/
private class TransformFailure extends RuntimeException
{
public TransformFailure()
{
}
}
/**
* this gets called when a transform attempt completes without any exceptions. if there are rules left
* in the rule map then they will belong successful injections.
*/
private boolean notifyRules()
{
// if we got here then we have performed a successful injection for each rule in the rule map
// if the map is empty then we ned to generate a warning that the rule was not injectable
if (ruleMap.isEmpty() && firstRule != null) {
// we parsed the rule but failed ever to inject it
TypeWarningException twe = new TypeWarningException("failed to find any matching trigger method in class " + TypeHelper.internalizeClass(triggerClassName));
ruleScript.recordTransform(loader, triggerClassName, null, null, firstRule, twe);
}
for (String key : ruleMap.keySet()) {
String triggerMethodName = getKeyTriggerMethodName(key);
String triggerMethodDescriptor = getKeyTriggerMethodDescriptor(key);
Rule rule = ruleMap.get(key);
if (!ruleScript.recordTransform(loader, triggerClassName, triggerMethodName, triggerMethodDescriptor, rule, null))
{
// rule script must have been deleted so purge rules and avoid installing the transformed code
purgeRules();
return false;
}
}
// ok install the transformed code
return true;
}
/**
* this gets called when a transform attempt fails. if there are rules left in the rule map
* then they will belong either to earlier successful injections or to the failed transform.
* in any case they need to be purged.
*/
private void purgeRules()
{
for (Rule rule : ruleMap.values()) {
rule.purge();
}
}
/**
* return a unique string key identifying a specific rule compiled against some class and method/signature in the
* context of a specific class loader
* @return
*/
private String getRuleKey(String triggerMethodName, String triggerMethodDescriptor)
{
return triggerClassName + "#" + triggerMethodName + "#" + triggerMethodDescriptor;
}
/**
* return the triggger method name used to construct the supplied rule key
* @param key
* @return
*/
private String getKeyTriggerMethodName(String key)
{
int firstHash = key.indexOf('#');
int secondHash = key.lastIndexOf('#');
return key.substring(firstHash + 1, secondHash - 1);
}
/**
* return the triggger method descriptor used to construct the supplied rule key
* @param key
* @return
*/
private String getKeyTriggerMethodDescriptor(String key)
{
int secondHash = key.lastIndexOf('#');
return key.substring(secondHash + 1);
}
/**
* pattern used to identify target method specs which include a return type preceding the
* method name and parameter type list. note that we can only handle a return type in
* cases where the parameter type list is also specified.
*/
private static final String JAVA_METHOD_SPEC_PATTERN = "[A-Za-z0-9$.]+ +[A-Za-z0-9$]+\\(.*\\)";
/**
* detect a method specification which includes a return type preceding the method name and transform
* it so that the return type is at the end.
* @param targetMethodSpec
* @return
*/
private String mungeMethodSpecReturnType(String targetMethodSpec)
{
// remove any leading or trailing spaces
targetMethodSpec = targetMethodSpec.trim();
if (targetMethodSpec.matches(JAVA_METHOD_SPEC_PATTERN)) {
// put the return type at the end
int spaceIdx = targetMethodSpec.indexOf(' ');
String returnType = targetMethodSpec.substring(0, spaceIdx);
targetMethodSpec = targetMethodSpec.substring(spaceIdx).trim() + returnType;
}
return targetMethodSpec;
}
/**
* get a class writer which will not attempt to load classes.The default classwriter tries this when a
* reference type local var frame slot aligns with a slot of reference type in a successor block's
* frame. This is merely so it can optimize a slot out of the frame change set in the special case where
* f1[slot].type < f2[slot].type or vice versa by using whichever is the maximal class. We avoid classloading
* by returning class Object.
* @param flags
* @return
*/
private ClassWriter getNonLoadingClassWriter(int flags)
{
return new ClassWriter(flags) {
protected String getCommonSuperClass(final String type1, final String type2) {
// if we always return Object we cannot go wrong
return "java/lang/Object";
}
};
}
private RuleScript ruleScript;
private String triggerClassName;
private String targetMethodName;
private String targetDescriptor;
private ClassLoader loader;
private HelperManager helperManager;
/**
* a hashmap indexing Rule instances using key classname.methodnameandsig@loaderhashcode. rules are
* added to this map when they are created and removed when the transform is recorded as having
* succeeded or failed. a method check adapter will create a rule when it begins a method scan and
* a method trigger adpater will look it up in order to reuse it
*/
private HashMap<String, Rule> ruleMap;
private Rule firstRule;
}