org.apache.catalina.loader.WebappClassLoader Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.catalina.loader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FilePermission;
import java.io.IOException;
import java.io.InputStream;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.charset.StandardCharsets;
import java.security.AccessControlException;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.Policy;
import java.security.PrivilegedAction;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.ConcurrentModificationException;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.ResourceBundle;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.jar.Attributes;
import java.util.jar.Attributes.Name;
import java.util.jar.Manifest;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.catalina.Globals;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.LifecycleState;
import org.apache.catalina.WebResource;
import org.apache.catalina.WebResourceRoot;
import org.apache.catalina.webresources.TomcatURLStreamHandlerFactory;
import org.apache.tomcat.InstrumentableClassLoader;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.IntrospectionUtils;
import org.apache.tomcat.util.res.StringManager;
/**
* Specialized web application class loader.
*
* This class loader is a full reimplementation of the
* URLClassLoader from the JDK. It is designed to be fully
* compatible with a normal URLClassLoader, although its internal
* behavior may be completely different.
*
* IMPLEMENTATION NOTE - By default, this class loader follows
* the delegation model required by the specification. The system class
* loader will be queried first, then the local repositories, and only then
* delegation to the parent class loader will occur. This allows the web
* application to override any shared class except the classes from J2SE.
* Special handling is provided from the JAXP XML parser interfaces, the JNDI
* interfaces, and the classes from the servlet API, which are never loaded
* from the webapp repositories. The delegate property
* allows an application to modify this behavior to move the parent class loader
* ahead of the local repositories.
*
* IMPLEMENTATION NOTE - Due to limitations in Jasper
* compilation technology, any repository which contains classes from
* the servlet API will be ignored by the class loader.
*
* IMPLEMENTATION NOTE - The class loader generates source
* URLs which include the full JAR URL when a class is loaded from a JAR file,
* which allows setting security permission at the class level, even when a
* class is contained inside a JAR.
*
* IMPLEMENTATION NOTE - Local repositories are searched in
* the order they are added via the initial constructor and/or any subsequent
* calls to addRepository() or addJar().
*
* IMPLEMENTATION NOTE - No check for sealing violations or
* security is made unless a security manager is present.
*
* IMPLEMENTATION NOTE - As of 8.0, this class
* loader implements {@link InstrumentableClassLoader}, permitting web
* application classes to instrument other classes in the same web
* application. It does not permit instrumentation of system or container
* classes or classes in other web apps.
*
* @author Remy Maucherat
* @author Craig R. McClanahan
*/
public class WebappClassLoader extends URLClassLoader
implements Lifecycle, InstrumentableClassLoader {
private static final org.apache.juli.logging.Log log=
org.apache.juli.logging.LogFactory.getLog( WebappClassLoader.class );
/**
* List of ThreadGroup names to ignore when scanning for web application
* started threads that need to be shut down.
*/
private static final List JVM_THREAD_GROUP_NAMES = new ArrayList<>();
private static final String JVN_THREAD_GROUP_SYSTEM = "system";
private static final String CLASS_FILE_SUFFIX = ".class";
static {
JVM_THREAD_GROUP_NAMES.add(JVN_THREAD_GROUP_SYSTEM);
JVM_THREAD_GROUP_NAMES.add("RMI Runtime");
}
protected class PrivilegedFindResourceByName
implements PrivilegedAction {
protected final String name;
protected final String path;
PrivilegedFindResourceByName(String name, String path) {
this.name = name;
this.path = path;
}
@Override
public ResourceEntry run() {
return findResourceInternal(name, path);
}
}
protected static final class PrivilegedGetClassLoader
implements PrivilegedAction {
public final Class clazz;
public PrivilegedGetClassLoader(Class clazz){
this.clazz = clazz;
}
@Override
public ClassLoader run() {
return clazz.getClassLoader();
}
}
// ------------------------------------------------------- Static Variables
/**
* Regular expression of package names which are not allowed to be loaded
* from a webapp class loader without delegating first.
*/
protected final Matcher packageTriggersDeny = Pattern.compile(
"^javax\\.el\\.|" +
"^javax\\.servlet\\.|" +
"^org\\.apache\\.(catalina|coyote|el|jasper|juli|naming|tomcat)\\."
).matcher("");
/**
* Regular expression of package names which are allowed to be loaded from a
* webapp class loader without delegating first and override any set by
* {@link #packageTriggersDeny}.
*/
protected final Matcher packageTriggersPermit =
Pattern.compile("^javax\\.servlet\\.jsp\\.jstl\\.").matcher("");
/**
* The string manager for this package.
*/
protected static final StringManager sm =
StringManager.getManager(Constants.Package);
// ----------------------------------------------------------- Constructors
/**
* Construct a new ClassLoader with no defined repositories and no
* parent ClassLoader.
*/
public WebappClassLoader() {
super(new URL[0]);
ClassLoader p = getParent();
if (p == null) {
p = getSystemClassLoader();
}
this.parent = p;
ClassLoader j = String.class.getClassLoader();
if (j == null) {
j = getSystemClassLoader();
while (j.getParent() != null) {
j = j.getParent();
}
}
this.j2seClassLoader = j;
securityManager = System.getSecurityManager();
if (securityManager != null) {
refreshPolicy();
}
}
/**
* Construct a new ClassLoader with no defined repositories and the given
* parent ClassLoader.
*
* Method is used via reflection -
* see {@link WebappLoader#createClassLoader()}
*
* @param parent Our parent class loader
*/
public WebappClassLoader(ClassLoader parent) {
super(new URL[0], parent);
ClassLoader p = getParent();
if (p == null) {
p = getSystemClassLoader();
}
this.parent = p;
ClassLoader j = String.class.getClassLoader();
if (j == null) {
j = getSystemClassLoader();
while (j.getParent() != null) {
j = j.getParent();
}
}
this.j2seClassLoader = j;
securityManager = System.getSecurityManager();
if (securityManager != null) {
refreshPolicy();
}
}
// ----------------------------------------------------- Instance Variables
/**
* Associated web resources for this webapp.
* TODO Review the use of resources in this class to see if further
* simplifications can be made.
*/
protected WebResourceRoot resources = null;
/**
* The cache of ResourceEntry for classes and resources we have loaded,
* keyed by resource path, not binary name. Path is used as the key since
* resources may be requested by binary name (classes) or path (other
* resources such as property files) and the mapping from binary name to
* path is unambiguous but the reverse mapping is ambiguous.
*/
protected final Map resourceEntries =
new ConcurrentHashMap<>();
/**
* Should this class loader delegate to the parent class loader
* before searching its own repositories (i.e. the
* usual Java2 delegation model)? If set to false,
* this class loader will search its own repositories first, and
* delegate to the parent only if the class or resource is not
* found locally. Note that the default, false, is
* the behavior called for by the servlet specification.
*/
protected boolean delegate = false;
private final HashMap jarModificationTimes = new HashMap<>();
/**
* A list of read File and Jndi Permission's required if this loader
* is for a web application context.
*/
protected final ArrayList permissionList = new ArrayList<>();
/**
* The PermissionCollection for each CodeSource for a web
* application context.
*/
protected final HashMap loaderPC = new HashMap<>();
/**
* Instance of the SecurityManager installed.
*/
protected final SecurityManager securityManager;
/**
* The parent class loader.
*/
protected final ClassLoader parent;
/**
* The bootstrap class loader used to load the J2SE classes. In some
* implementations this class loader is always null and in
* those cases {@link ClassLoader#getParent()} will be called recursively on
* the system class loader and the last non-null result used.
*/
protected final ClassLoader j2seClassLoader;
/**
* Has this component been started?
*/
protected boolean started = false;
/**
* need conversion for properties files
*/
protected boolean needConvert = false;
/**
* All permission.
*/
protected final Permission allPermission = new java.security.AllPermission();
/**
* Should Tomcat attempt to null out any static or final fields from loaded
* classes when a web application is stopped as a work around for apparent
* garbage collection bugs and application coding errors? There have been
* some issues reported with log4j when this option is true. Applications
* without memory leaks using recent JVMs should operate correctly with this
* option set to false. If not specified, the default value of
* false will be used.
*/
private boolean clearReferencesStatic = false;
/**
* Should Tomcat attempt to terminate threads that have been started by the
* web application? Stopping threads is performed via the deprecated (for
* good reason) Thread.stop() method and is likely to result in
* instability. As such, enabling this should be viewed as an option of last
* resort in a development environment and is not recommended in a
* production environment. If not specified, the default value of
* false will be used.
*/
private boolean clearReferencesStopThreads = false;
/**
* Should Tomcat attempt to terminate any {@link java.util.TimerThread}s
* that have been started by the web application? If not specified, the
* default value of false will be used.
*/
private boolean clearReferencesStopTimerThreads = false;
/**
* Should Tomcat call {@link org.apache.juli.logging.LogFactory#release()}
* when the class loader is stopped? If not specified, the default value
* of true is used. Changing the default setting is likely to
* lead to memory leaks and other issues.
*/
private boolean clearReferencesLogFactoryRelease = true;
/**
* If an HttpClient keep-alive timer thread has been started by this web
* application and is still running, should Tomcat change the context class
* loader from the current {@link WebappClassLoader} to
* {@link WebappClassLoader#parent} to prevent a memory leak? Note that the
* keep-alive timer thread will stop on its own once the keep-alives all
* expire however, on a busy system that might not happen for some time.
*/
private boolean clearReferencesHttpClientKeepAliveThread = true;
/**
* Holds the class file transformers decorating this class loader. The
* CopyOnWriteArrayList is thread safe. It is expensive on writes, but
* those should be rare. It is very fast on reads, since synchronization
* is not actually used. Importantly, the ClassLoader will never block
* iterating over the transformers while loading a class.
*/
private final List transformers = new CopyOnWriteArrayList<>();
// ------------------------------------------------------------- Properties
/**
* Get associated resources.
*/
public WebResourceRoot getResources() {
return this.resources;
}
/**
* Set associated resources.
*/
public void setResources(WebResourceRoot resources) {
this.resources = resources;
}
/**
* Return the context name for this class loader.
*/
public String getContextName() {
if (resources == null) {
return "Unknown";
} else {
return resources.getContext().getName();
}
}
/**
* Return the "delegate first" flag for this class loader.
*/
public boolean getDelegate() {
return (this.delegate);
}
/**
* Set the "delegate first" flag for this class loader.
* If this flag is true, this class loader delegates
* to the parent class loader
* before searching its own repositories, as
* in an ordinary (non-servlet) chain of Java class loaders.
* If set to false (the default),
* this class loader will search its own repositories first, and
* delegate to the parent only if the class or resource is not
* found locally, as per the servlet specification.
*
* @param delegate The new "delegate first" flag
*/
public void setDelegate(boolean delegate) {
this.delegate = delegate;
}
/**
* If there is a Java SecurityManager create a read permission for the
* target of the given URL as appropriate.
*
* @param url URL for a file or directory on local system
*/
void addPermission(URL url) {
if (url == null) {
return;
}
if (securityManager != null) {
String protocol = url.getProtocol();
if ("file".equalsIgnoreCase(protocol)) {
URI uri;
File f;
String path;
try {
uri = url.toURI();
f = new File(uri);
path = f.getCanonicalPath();
} catch (IOException | URISyntaxException e) {
log.warn(sm.getString(
"webappClassLoader.addPermisionNoCanonicalFile",
url.toExternalForm()));
return;
}
if (f.isFile()) {
// Allow the file to be read
addPermission(new FilePermission(path, "read"));
} else if (f.isDirectory()) {
addPermission(new FilePermission(path, "read"));
addPermission(new FilePermission(
path + File.separator + "-", "read"));
} else {
// File does not exist - ignore (shouldn't happen)
}
} else {
// Unsupported URL protocol
log.warn(sm.getString(
"webappClassLoader.addPermisionNoProtocol",
protocol, url.toExternalForm()));
}
}
}
/**
* If there is a Java SecurityManager create a Permission.
*
* @param permission The permission
*/
void addPermission(Permission permission) {
if ((securityManager != null) && (permission != null)) {
permissionList.add(permission);
}
}
/**
* Return the clearReferencesStatic flag for this Context.
*/
public boolean getClearReferencesStatic() {
return (this.clearReferencesStatic);
}
/**
* Set the clearReferencesStatic feature for this Context.
*
* @param clearReferencesStatic The new flag value
*/
public void setClearReferencesStatic(boolean clearReferencesStatic) {
this.clearReferencesStatic = clearReferencesStatic;
}
/**
* Return the clearReferencesStopThreads flag for this Context.
*/
public boolean getClearReferencesStopThreads() {
return (this.clearReferencesStopThreads);
}
/**
* Set the clearReferencesStopThreads feature for this Context.
*
* @param clearReferencesStopThreads The new flag value
*/
public void setClearReferencesStopThreads(
boolean clearReferencesStopThreads) {
this.clearReferencesStopThreads = clearReferencesStopThreads;
}
/**
* Return the clearReferencesStopTimerThreads flag for this Context.
*/
public boolean getClearReferencesStopTimerThreads() {
return (this.clearReferencesStopTimerThreads);
}
/**
* Set the clearReferencesStopTimerThreads feature for this Context.
*
* @param clearReferencesStopTimerThreads The new flag value
*/
public void setClearReferencesStopTimerThreads(
boolean clearReferencesStopTimerThreads) {
this.clearReferencesStopTimerThreads = clearReferencesStopTimerThreads;
}
/**
* Return the clearReferencesLogFactoryRelease flag for this Context.
*/
public boolean getClearReferencesLogFactoryRelease() {
return (this.clearReferencesLogFactoryRelease);
}
/**
* Set the clearReferencesLogFactoryRelease feature for this Context.
*
* @param clearReferencesLogFactoryRelease The new flag value
*/
public void setClearReferencesLogFactoryRelease(
boolean clearReferencesLogFactoryRelease) {
this.clearReferencesLogFactoryRelease =
clearReferencesLogFactoryRelease;
}
/**
* Return the clearReferencesHttpClientKeepAliveThread flag for this
* Context.
*/
public boolean getClearReferencesHttpClientKeepAliveThread() {
return (this.clearReferencesHttpClientKeepAliveThread);
}
/**
* Set the clearReferencesHttpClientKeepAliveThread feature for this
* Context.
*
* @param clearReferencesHttpClientKeepAliveThread The new flag value
*/
public void setClearReferencesHttpClientKeepAliveThread(
boolean clearReferencesHttpClientKeepAliveThread) {
this.clearReferencesHttpClientKeepAliveThread =
clearReferencesHttpClientKeepAliveThread;
}
// ------------------------------------------------------- Reloader Methods
/**
* Adds the specified class file transformer to this class loader. The
* transformer will then be able to modify the bytecode of any classes
* loaded by this class loader after the invocation of this method.
*
* @param transformer The transformer to add to the class loader
*/
@Override
public void addTransformer(ClassFileTransformer transformer) {
if (transformer == null) {
throw new IllegalArgumentException(sm.getString(
"webappClassLoader.addTransformer.illegalArgument", getContextName()));
}
if (this.transformers.contains(transformer)) {
// if the same instance of this transformer was already added, bail out
log.warn(sm.getString("webappClassLoader.addTransformer.duplicate",
transformer, getContextName()));
return;
}
this.transformers.add(transformer);
log.info(sm.getString("webappClassLoader.addTransformer", transformer, getContextName()));
}
/**
* Removes the specified class file transformer from this class loader.
* It will no longer be able to modify the byte code of any classes
* loaded by the class loader after the invocation of this method.
* However, any classes already modified by this transformer will
* remain transformed.
*
* @param transformer The transformer to remove
*/
@Override
public void removeTransformer(ClassFileTransformer transformer) {
if (transformer == null) {
return;
}
if (this.transformers.remove(transformer)) {
log.info(sm.getString("webappClassLoader.removeTransformer",
transformer, getContextName()));
return;
}
}
/**
* Returns a copy of this class loader without any class file
* transformers. This is a tool often used by Java Persistence API
* providers to inspect entity classes in the absence of any
* instrumentation, something that can't be guaranteed within the
* context of a {@link ClassFileTransformer}'s
* {@link ClassFileTransformer#transform(ClassLoader, String, Class,
* ProtectionDomain, byte[]) transform} method.
*
* The returned class loader's resource cache will have been cleared
* so that classes already instrumented will not be retained or
* returned.
*
* @return the transformer-free copy of this class loader.
*/
@Override
public WebappClassLoader copyWithoutTransformers() {
WebappClassLoader result = new WebappClassLoader(getParent());
result.resources = this.resources;
result.delegate = this.delegate;
result.started = this.started;
result.needConvert = this.needConvert;
result.clearReferencesStatic = this.clearReferencesStatic;
result.clearReferencesStopThreads = this.clearReferencesStopThreads;
result.clearReferencesStopTimerThreads = this.clearReferencesStopTimerThreads;
result.clearReferencesLogFactoryRelease = this.clearReferencesLogFactoryRelease;
result.clearReferencesHttpClientKeepAliveThread = this.clearReferencesHttpClientKeepAliveThread;
result.jarModificationTimes.putAll(this.jarModificationTimes);
result.permissionList.addAll(this.permissionList);
result.loaderPC.putAll(this.loaderPC);
try {
result.start();
} catch (LifecycleException e) {
throw new IllegalStateException(e);
}
return result;
}
/**
* Have one or more classes or resources been modified so that a reload
* is appropriate?
*/
public boolean modified() {
if (log.isDebugEnabled())
log.debug("modified()");
for (Entry entry : resourceEntries.entrySet()) {
long cachedLastModified = entry.getValue().lastModified;
long lastModified = resources.getClassLoaderResource(
entry.getKey()).getLastModified();
if (lastModified != cachedLastModified) {
if( log.isDebugEnabled() )
log.debug(sm.getString("webappClassLoader.resourceModified",
entry.getKey(),
new Date(cachedLastModified),
new Date(lastModified)));
return true;
}
}
// Check if JARs have been added or removed
WebResource[] jars = resources.listResources("/WEB-INF/lib");
// Filter out non-JAR resources
int jarCount = 0;
for (WebResource jar : jars) {
if (jar.getName().endsWith(".jar") && jar.isFile() && jar.canRead()) {
jarCount++;
Long recordedLastModified = jarModificationTimes.get(jar.getName());
if (recordedLastModified == null) {
// Jar has been added
log.info(sm.getString("webappClassLoader.jarsAdded",
resources.getContext().getName()));
return true;
}
if (recordedLastModified.longValue() != jar.getLastModified()) {
// Jar has been changed
log.info(sm.getString("webappClassLoader.jarsModified",
resources.getContext().getName()));
return true;
}
}
}
if (jarCount < jarModificationTimes.size()){
log.info(sm.getString("webappClassLoader.jarsRemoved",
resources.getContext().getName()));
return true;
}
// No classes have been modified
return false;
}
/**
* Render a String representation of this object.
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder("WebappClassLoader\r\n");
sb.append(" context: ");
sb.append(getContextName());
sb.append("\r\n");
sb.append(" delegate: ");
sb.append(delegate);
sb.append("\r\n");
if (this.parent != null) {
sb.append("----------> Parent Classloader:\r\n");
sb.append(this.parent.toString());
sb.append("\r\n");
}
if (this.transformers.size() > 0) {
sb.append("----------> Class file transformers:\r\n");
for (ClassFileTransformer transformer : this.transformers) {
sb.append(transformer).append("\r\n");
}
}
return (sb.toString());
}
// ---------------------------------------------------- ClassLoader Methods
/**
* Expose this method for use by the unit tests.
*/
protected final Class doDefineClass(String name, byte[] b, int off, int len,
ProtectionDomain protectionDomain) {
return super.defineClass(name, b, off, len, protectionDomain);
}
/**
* Find the specified class in our local repositories, if possible. If
* not found, throw ClassNotFoundException.
*
* @param name The binary name of the class to be loaded
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public Class findClass(String name) throws ClassNotFoundException {
if (log.isDebugEnabled())
log.debug(" findClass(" + name + ")");
// Cannot load anything from local repositories if class loader is stopped
if (!started) {
throw new ClassNotFoundException(name);
}
// (1) Permission to define this class when using a SecurityManager
if (securityManager != null) {
int i = name.lastIndexOf('.');
if (i >= 0) {
try {
if (log.isTraceEnabled())
log.trace(" securityManager.checkPackageDefinition");
securityManager.checkPackageDefinition(name.substring(0,i));
} catch (Exception se) {
if (log.isTraceEnabled())
log.trace(" -->Exception-->ClassNotFoundException", se);
throw new ClassNotFoundException(name, se);
}
}
}
// Ask our superclass to locate this class, if possible
// (throws ClassNotFoundException if it is not found)
Class clazz = null;
try {
if (log.isTraceEnabled())
log.trace(" findClassInternal(" + name + ")");
try {
clazz = findClassInternal(name);
} catch(ClassNotFoundException cnfe) {
if (log.isDebugEnabled())
log.debug(" --> Returning ClassNotFoundException");
throw cnfe;
} catch(AccessControlException ace) {
log.warn("WebappClassLoader.findClassInternal(" + name
+ ") security exception: " + ace.getMessage(), ace);
throw new ClassNotFoundException(name, ace);
} catch (RuntimeException e) {
if (log.isTraceEnabled())
log.trace(" -->RuntimeException Rethrown", e);
throw e;
}
} catch (ClassNotFoundException e) {
if (log.isTraceEnabled())
log.trace(" --> Passing on ClassNotFoundException");
throw e;
}
// Return the class we have located
if (log.isTraceEnabled())
log.debug(" Returning class " + clazz);
if (log.isTraceEnabled()) {
ClassLoader cl;
if (Globals.IS_SECURITY_ENABLED){
cl = AccessController.doPrivileged(
new PrivilegedGetClassLoader(clazz));
} else {
cl = clazz.getClassLoader();
}
log.debug(" Loaded by " + cl.toString());
}
return (clazz);
}
/**
* Find the specified resource in our local repository, and return a
* URL referring to it, or null if this resource
* cannot be found.
*
* @param name Name of the resource to be found
*/
@Override
public URL findResource(final String name) {
if (log.isDebugEnabled())
log.debug(" findResource(" + name + ")");
URL url = null;
String path = nameToPath(name);
ResourceEntry entry = resourceEntries.get(path);
if (entry == null) {
if (securityManager != null) {
PrivilegedAction dp =
new PrivilegedFindResourceByName(name, path);
entry = AccessController.doPrivileged(dp);
} else {
entry = findResourceInternal(name, path);
}
}
if (entry != null) {
url = entry.source;
}
if (log.isDebugEnabled()) {
if (url != null)
log.debug(" --> Returning '" + url.toString() + "'");
else
log.debug(" --> Resource not found, returning null");
}
return (url);
}
/**
* Return an enumeration of URLs representing all of the
* resources with the given name. If no resources with this name are
* found, return an empty enumeration.
*
* @param name Name of the resources to be found
*
* @exception IOException if an input/output error occurs
*/
@Override
public Enumeration findResources(String name) throws IOException {
if (log.isDebugEnabled())
log.debug(" findResources(" + name + ")");
LinkedHashSet result = new LinkedHashSet<>();
String path = nameToPath(name);
WebResource[] webResources = resources.getClassLoaderResources(path);
for (WebResource webResource : webResources) {
if (webResource.exists()) {
result.add(webResource.getURL());
}
}
return Collections.enumeration(result);
}
/**
* Find the resource with the given name. A resource is some data
* (images, audio, text, etc.) that can be accessed by class code in a
* way that is independent of the location of the code. The name of a
* resource is a "/"-separated path name that identifies the resource.
* If the resource cannot be found, return null.
*
* This method searches according to the following algorithm, returning
* as soon as it finds the appropriate URL. If the resource cannot be
* found, returns null.
*
* - If the
delegate property is set to true,
* call the getResource() method of the parent class
* loader, if any.
* - Call
findResource() to find this resource in our
* locally defined repositories.
* - Call the
getResource() method of the parent class
* loader, if any.
*
*
* @param name Name of the resource to return a URL for
*/
@Override
public URL getResource(String name) {
if (log.isDebugEnabled())
log.debug("getResource(" + name + ")");
URL url = null;
// (1) Delegate to parent if requested
if (delegate) {
if (log.isDebugEnabled())
log.debug(" Delegating to parent classloader " + parent);
url = parent.getResource(name);
if (url != null) {
if (log.isDebugEnabled())
log.debug(" --> Returning '" + url.toString() + "'");
return (url);
}
}
// (2) Search local repositories
url = findResource(name);
if (url != null) {
if (log.isDebugEnabled())
log.debug(" --> Returning '" + url.toString() + "'");
return (url);
}
// (3) Delegate to parent unconditionally if not already attempted
if( !delegate ) {
url = parent.getResource(name);
if (url != null) {
if (log.isDebugEnabled())
log.debug(" --> Returning '" + url.toString() + "'");
return (url);
}
}
// (4) Resource was not found
if (log.isDebugEnabled())
log.debug(" --> Resource not found, returning null");
return (null);
}
/**
* Find the resource with the given name, and return an input stream
* that can be used for reading it. The search order is as described
* for getResource(), after checking to see if the resource
* data has been previously cached. If the resource cannot be found,
* return null.
*
* @param name Name of the resource to return an input stream for
*/
@Override
public InputStream getResourceAsStream(String name) {
if (log.isDebugEnabled())
log.debug("getResourceAsStream(" + name + ")");
InputStream stream = null;
// (0) Check for a cached copy of this resource
stream = findLoadedResource(name);
if (stream != null) {
if (log.isDebugEnabled())
log.debug(" --> Returning stream from cache");
return (stream);
}
// (1) Delegate to parent if requested
if (delegate) {
if (log.isDebugEnabled())
log.debug(" Delegating to parent classloader " + parent);
stream = parent.getResourceAsStream(name);
if (stream != null) {
// FIXME - cache???
if (log.isDebugEnabled())
log.debug(" --> Returning stream from parent");
return (stream);
}
}
// (2) Search local repositories
if (log.isDebugEnabled())
log.debug(" Searching local repositories");
URL url = findResource(name);
if (url != null) {
// FIXME - cache???
if (log.isDebugEnabled())
log.debug(" --> Returning stream from local");
stream = findLoadedResource(name);
if (stream != null)
return (stream);
}
// (3) Delegate to parent unconditionally
if (!delegate) {
if (log.isDebugEnabled())
log.debug(" Delegating to parent classloader unconditionally " + parent);
stream = parent.getResourceAsStream(name);
if (stream != null) {
// FIXME - cache???
if (log.isDebugEnabled())
log.debug(" --> Returning stream from parent");
return (stream);
}
}
// (4) Resource was not found
if (log.isDebugEnabled())
log.debug(" --> Resource not found, returning null");
return (null);
}
/**
* Load the class with the specified name. This method searches for
* classes in the same manner as loadClass(String, boolean)
* with false as the second argument.
*
* @param name The binary name of the class to be loaded
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public Class loadClass(String name) throws ClassNotFoundException {
return (loadClass(name, false));
}
/**
* Load the class with the specified name, searching using the following
* algorithm until it finds and returns the class. If the class cannot
* be found, returns ClassNotFoundException.
*
* - Call
findLoadedClass(String) to check if the
* class has already been loaded. If it has, the same
* Class object is returned.
* - If the
delegate property is set to true,
* call the loadClass() method of the parent class
* loader, if any.
* - Call
findClass() to find this class in our locally
* defined repositories.
* - Call the
loadClass() method of our parent
* class loader, if any.
*
* If the class was found using the above steps, and the
* resolve flag is true, this method will then
* call resolveClass(Class) on the resulting Class object.
*
* @param name The binary name of the class to be loaded
* @param resolve If true then resolve the class
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public synchronized Class loadClass(String name, boolean resolve)
throws ClassNotFoundException {
if (log.isDebugEnabled())
log.debug("loadClass(" + name + ", " + resolve + ")");
Class clazz = null;
// Log access to stopped classloader
if (!started) {
try {
throw new IllegalStateException();
} catch (IllegalStateException e) {
log.info(sm.getString("webappClassLoader.stopped", name), e);
}
}
// (0) Check our previously loaded local class cache
clazz = findLoadedClass0(name);
if (clazz != null) {
if (log.isDebugEnabled())
log.debug(" Returning class from cache");
if (resolve)
resolveClass(clazz);
return (clazz);
}
// (0.1) Check our previously loaded class cache
clazz = findLoadedClass(name);
if (clazz != null) {
if (log.isDebugEnabled())
log.debug(" Returning class from cache");
if (resolve)
resolveClass(clazz);
return (clazz);
}
// (0.2) Try loading the class with the system class loader, to prevent
// the webapp from overriding J2SE classes
String resourceName = binaryNameToPath(name, false);
if (j2seClassLoader.getResource(resourceName) != null) {
try {
clazz = j2seClassLoader.loadClass(name);
if (clazz != null) {
if (resolve)
resolveClass(clazz);
return (clazz);
}
} catch (ClassNotFoundException e) {
// Ignore
}
}
// (0.5) Permission to access this class when using a SecurityManager
if (securityManager != null) {
int i = name.lastIndexOf('.');
if (i >= 0) {
try {
securityManager.checkPackageAccess(name.substring(0,i));
} catch (SecurityException se) {
String error = "Security Violation, attempt to use " +
"Restricted Class: " + name;
log.info(error, se);
throw new ClassNotFoundException(error, se);
}
}
}
boolean delegateLoad = delegate || filter(name);
// (1) Delegate to our parent if requested
if (delegateLoad) {
if (log.isDebugEnabled())
log.debug(" Delegating to parent classloader1 " + parent);
try {
clazz = Class.forName(name, false, parent);
if (clazz != null) {
if (log.isDebugEnabled())
log.debug(" Loading class from parent");
if (resolve)
resolveClass(clazz);
return (clazz);
}
} catch (ClassNotFoundException e) {
// Ignore
}
}
// (2) Search local repositories
if (log.isDebugEnabled())
log.debug(" Searching local repositories");
try {
clazz = findClass(name);
if (clazz != null) {
if (log.isDebugEnabled())
log.debug(" Loading class from local repository");
if (resolve)
resolveClass(clazz);
return (clazz);
}
} catch (ClassNotFoundException e) {
// Ignore
}
// (3) Delegate to parent unconditionally
if (!delegateLoad) {
if (log.isDebugEnabled())
log.debug(" Delegating to parent classloader at end: " + parent);
try {
clazz = Class.forName(name, false, parent);
if (clazz != null) {
if (log.isDebugEnabled())
log.debug(" Loading class from parent");
if (resolve)
resolveClass(clazz);
return (clazz);
}
} catch (ClassNotFoundException e) {
// Ignore
}
}
throw new ClassNotFoundException(name);
}
/**
* Get the Permissions for a CodeSource. If this instance
* of WebappClassLoader is for a web application context,
* add read FilePermission or JndiPermissions for the base
* directory (if unpacked),
* the context URL, and jar file resources.
*
* @param codeSource where the code was loaded from
* @return PermissionCollection for CodeSource
*/
@Override
protected PermissionCollection getPermissions(CodeSource codeSource) {
String codeUrl = codeSource.getLocation().toString();
PermissionCollection pc;
if ((pc = loaderPC.get(codeUrl)) == null) {
pc = super.getPermissions(codeSource);
if (pc != null) {
Iterator perms = permissionList.iterator();
while (perms.hasNext()) {
Permission p = perms.next();
pc.add(p);
}
loaderPC.put(codeUrl,pc);
}
}
return (pc);
}
/**
* {@inheritDoc}
*
* Note that list of URLs returned by this method may not be complete. The
* web application class loader accesses class loader resources via the
* {@link WebResourceRoot} which supports the arbitrary mapping of
* additional files, directories and contents of JAR files under
* WEB-INF/classes. Any such resources will not be included in the URLs
* returned here.
*/
@Override
public URL[] getURLs() {
return super.getURLs();
}
// ------------------------------------------------------ Lifecycle Methods
/**
* Add a lifecycle event listener to this component.
*
* @param listener The listener to add
*/
@Override
public void addLifecycleListener(LifecycleListener listener) {
// NOOP
}
/**
* Get the lifecycle listeners associated with this lifecycle. If this
* Lifecycle has no listeners registered, a zero-length array is returned.
*/
@Override
public LifecycleListener[] findLifecycleListeners() {
return new LifecycleListener[0];
}
/**
* Remove a lifecycle event listener from this component.
*
* @param listener The listener to remove
*/
@Override
public void removeLifecycleListener(LifecycleListener listener) {
// NOOP
}
/**
* Obtain the current state of the source component.
*
* @return The current state of the source component.
*/
@Override
public LifecycleState getState() {
return LifecycleState.NEW;
}
/**
* {@inheritDoc}
*/
@Override
public String getStateName() {
return getState().toString();
}
@Override
public void init() {
// NOOP
}
/**
* Start the class loader.
*
* @exception LifecycleException if a lifecycle error occurs
*/
@Override
public void start() throws LifecycleException {
WebResource classes = resources.getResource("/WEB-INF/classes");
if (classes.isDirectory() && classes.canRead()) {
addURL(classes.getURL());
}
WebResource[] jars = resources.listResources("/WEB-INF/lib");
for (WebResource jar : jars) {
if (jar.getName().endsWith(".jar") && jar.isFile() && jar.canRead()) {
addURL(jar.getURL());
jarModificationTimes.put(
jar.getName(), Long.valueOf(jar.getLastModified()));
}
}
started = true;
String encoding = null;
try {
encoding = System.getProperty("file.encoding");
} catch (SecurityException e) {
return;
}
if (encoding.indexOf("EBCDIC")!=-1) {
needConvert = true;
}
}
public boolean isStarted() {
return started;
}
/**
* Stop the class loader.
*
* @exception LifecycleException if a lifecycle error occurs
*/
@Override
public void stop() throws LifecycleException {
// Clearing references should be done before setting started to
// false, due to possible side effects
clearReferences();
started = false;
resourceEntries.clear();
jarModificationTimes.clear();
resources = null;
permissionList.clear();
loaderPC.clear();
}
@Override
public void destroy() {
// NOOP
}
// ------------------------------------------------------ Protected Methods
/**
* Clear references.
*/
protected void clearReferences() {
// De-register any remaining JDBC drivers
clearReferencesJdbc();
// Stop any threads the web application started
clearReferencesThreads();
// Check for leaks triggered by ThreadLocals loaded by this class loader
checkThreadLocalsForLeaks();
// Clear RMI Targets loaded by this class loader
clearReferencesRmiTargets();
// Null out any static or final fields from loaded classes,
// as a workaround for apparent garbage collection bugs
if (clearReferencesStatic) {
clearReferencesStaticFinal();
}
// Clear the IntrospectionUtils cache.
IntrospectionUtils.clear();
// Clear the classloader reference in common-logging
if (clearReferencesLogFactoryRelease) {
org.apache.juli.logging.LogFactory.release(this);
}
// Clear the resource bundle cache
// This shouldn't be necessary, the cache uses weak references but
// it has caused leaks. Oddly, using the leak detection code in
// standard host allows the class loader to be GC'd. This has been seen
// on Sun but not IBM JREs. Maybe a bug in Sun's GC impl?
clearReferencesResourceBundles();
// Clear the classloader reference in the VM's bean introspector
java.beans.Introspector.flushCaches();
// Clear any custom URLStreamHandlers
TomcatURLStreamHandlerFactory.release(this);
}
/**
* Deregister any JDBC drivers registered by the webapp that the webapp
* forgot. This is made unnecessary complex because a) DriverManager
* checks the class loader of the calling class (it would be much easier
* if it checked the context class loader) b) using reflection would
* create a dependency on the DriverManager implementation which can,
* and has, changed.
*
* We can't just create an instance of JdbcLeakPrevention as it will be
* loaded by the common class loader (since it's .class file is in the
* $CATALINA_HOME/lib directory). This would fail DriverManager's check
* on the class loader of the calling class. So, we load the bytes via
* our parent class loader but define the class with this class loader
* so the JdbcLeakPrevention looks like a webapp class to the
* DriverManager.
*
* If only apps cleaned up after themselves...
*/
private final void clearReferencesJdbc() {
InputStream is = getResourceAsStream(
"org/apache/catalina/loader/JdbcLeakPrevention.class");
// We know roughly how big the class will be (~ 1K) so allow 2k as a
// starting point
byte[] classBytes = new byte[2048];
int offset = 0;
try {
int read = is.read(classBytes, offset, classBytes.length-offset);
while (read > -1) {
offset += read;
if (offset == classBytes.length) {
// Buffer full - double size
byte[] tmp = new byte[classBytes.length * 2];
System.arraycopy(classBytes, 0, tmp, 0, classBytes.length);
classBytes = tmp;
}
read = is.read(classBytes, offset, classBytes.length-offset);
}
Class lpClass =
defineClass("org.apache.catalina.loader.JdbcLeakPrevention",
classBytes, 0, offset, this.getClass().getProtectionDomain());
Object obj = lpClass.newInstance();
@SuppressWarnings("unchecked")
List driverNames = (List) obj.getClass().getMethod(
"clearJdbcDriverRegistrations").invoke(obj);
for (String name : driverNames) {
log.error(sm.getString("webappClassLoader.clearJdbc",
getContextName(), name));
}
} catch (Exception e) {
// So many things to go wrong above...
Throwable t = ExceptionUtils.unwrapInvocationTargetException(e);
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString(
"webappClassLoader.jdbcRemoveFailed", getContextName()), t);
} finally {
if (is != null) {
try {
is.close();
} catch (IOException ioe) {
log.warn(sm.getString(
"webappClassLoader.jdbcRemoveStreamError",
getContextName()), ioe);
}
}
}
}
private final void clearReferencesStaticFinal() {
Collection values = resourceEntries.values();
Iterator loadedClasses = values.iterator();
//
// walk through all loaded class to trigger initialization for
// any uninitialized classes, otherwise initialization of
// one class may call a previously cleared class.
while(loadedClasses.hasNext()) {
ResourceEntry entry = loadedClasses.next();
if (entry.loadedClass != null) {
Class clazz = entry.loadedClass;
try {
Field[] fields = clazz.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
if(Modifier.isStatic(fields[i].getModifiers())) {
fields[i].get(null);
break;
}
}
} catch(Throwable t) {
// Ignore
}
}
}
loadedClasses = values.iterator();
while (loadedClasses.hasNext()) {
ResourceEntry entry = loadedClasses.next();
if (entry.loadedClass != null) {
Class clazz = entry.loadedClass;
try {
Field[] fields = clazz.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
Field field = fields[i];
int mods = field.getModifiers();
if (field.getType().isPrimitive()
|| (field.getName().indexOf("$") != -1)) {
continue;
}
if (Modifier.isStatic(mods)) {
try {
field.setAccessible(true);
if (Modifier.isFinal(mods)) {
if (!((field.getType().getName().startsWith("java."))
|| (field.getType().getName().startsWith("javax.")))) {
nullInstance(field.get(null));
}
} else {
field.set(null, null);
if (log.isDebugEnabled()) {
log.debug("Set field " + field.getName()
+ " to null in class " + clazz.getName());
}
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
if (log.isDebugEnabled()) {
log.debug("Could not set field " + field.getName()
+ " to null in class " + clazz.getName(), t);
}
}
}
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
if (log.isDebugEnabled()) {
log.debug("Could not clean fields for class " + clazz.getName(), t);
}
}
}
}
}
private void nullInstance(Object instance) {
if (instance == null) {
return;
}
Field[] fields = instance.getClass().getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
Field field = fields[i];
int mods = field.getModifiers();
if (field.getType().isPrimitive()
|| (field.getName().indexOf("$") != -1)) {
continue;
}
try {
field.setAccessible(true);
if (Modifier.isStatic(mods) && Modifier.isFinal(mods)) {
// Doing something recursively is too risky
continue;
}
Object value = field.get(instance);
if (null != value) {
Class valueClass = value.getClass();
if (!loadedByThisOrChild(valueClass)) {
if (log.isDebugEnabled()) {
log.debug("Not setting field " + field.getName() +
" to null in object of class " +
instance.getClass().getName() +
" because the referenced object was of type " +
valueClass.getName() +
" which was not loaded by this WebappClassLoader.");
}
} else {
field.set(instance, null);
if (log.isDebugEnabled()) {
log.debug("Set field " + field.getName()
+ " to null in class " + instance.getClass().getName());
}
}
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
if (log.isDebugEnabled()) {
log.debug("Could not set field " + field.getName()
+ " to null in object instance of class "
+ instance.getClass().getName(), t);
}
}
}
}
@SuppressWarnings("deprecation") // thread.stop()
private void clearReferencesThreads() {
Thread[] threads = getThreads();
List executorThreadsToStop = new ArrayList<>();
// Iterate over the set of threads
for (Thread thread : threads) {
if (thread != null) {
ClassLoader ccl = thread.getContextClassLoader();
if (ccl == this) {
// Don't warn about this thread
if (thread == Thread.currentThread()) {
continue;
}
// JVM controlled threads
ThreadGroup tg = thread.getThreadGroup();
if (tg != null &&
JVM_THREAD_GROUP_NAMES.contains(tg.getName())) {
// HttpClient keep-alive threads
if (clearReferencesHttpClientKeepAliveThread &&
thread.getName().equals("Keep-Alive-Timer")) {
thread.setContextClassLoader(parent);
log.debug(sm.getString(
"webappClassLoader.checkThreadsHttpClient"));
}
// Don't warn about remaining JVM controlled threads
continue;
}
// Skip threads that have already died
if (!thread.isAlive()) {
continue;
}
// TimerThread can be stopped safely so treat separately
// "java.util.TimerThread" in Sun/Oracle JDK
// "java.util.Timer$TimerImpl" in Apache Harmony and in IBM JDK
if (thread.getClass().getName().startsWith("java.util.Timer") &&
clearReferencesStopTimerThreads) {
clearReferencesStopTimerThread(thread);
continue;
}
if (isRequestThread(thread)) {
log.error(sm.getString("webappClassLoader.warnRequestThread",
getContextName(), thread.getName()));
} else {
log.error(sm.getString("webappClassLoader.warnThread",
getContextName(), thread.getName()));
}
// Don't try an stop the threads unless explicitly
// configured to do so
if (!clearReferencesStopThreads) {
continue;
}
// If the thread has been started via an executor, try
// shutting down the executor
boolean usingExecutor = false;
try {
// Runnable wrapped by Thread
// "target" in Sun/Oracle JDK
// "runnable" in IBM JDK
// "action" in Apache Harmony
Object target = null;
for (String fieldName : new String[] { "target",
"runnable", "action" }) {
try {
Field targetField = thread.getClass()
.getDeclaredField(fieldName);
targetField.setAccessible(true);
target = targetField.get(thread);
break;
} catch (NoSuchFieldException nfe) {
continue;
}
}
// "java.util.concurrent" code is in public domain,
// so all implementations are similar
if (target != null &&
target.getClass().getCanonicalName() != null
&& target.getClass().getCanonicalName().equals(
"java.util.concurrent.ThreadPoolExecutor.Worker")) {
Field executorField =
target.getClass().getDeclaredField("this$0");
executorField.setAccessible(true);
Object executor = executorField.get(target);
if (executor instanceof ThreadPoolExecutor) {
((ThreadPoolExecutor) executor).shutdownNow();
usingExecutor = true;
}
}
} catch (SecurityException e) {
log.warn(sm.getString(
"webappClassLoader.stopThreadFail",
thread.getName(), getContextName()), e);
} catch (NoSuchFieldException e) {
log.warn(sm.getString(
"webappClassLoader.stopThreadFail",
thread.getName(), getContextName()), e);
} catch (IllegalArgumentException e) {
log.warn(sm.getString(
"webappClassLoader.stopThreadFail",
thread.getName(), getContextName()), e);
} catch (IllegalAccessException e) {
log.warn(sm.getString(
"webappClassLoader.stopThreadFail",
thread.getName(), getContextName()), e);
}
if (usingExecutor) {
// Executor may take a short time to stop all the
// threads. Make a note of threads that should be
// stopped and check them at the end of the method.
executorThreadsToStop.add(thread);
} else {
// This method is deprecated and for good reason. This
// is very risky code but is the only option at this
// point. A *very* good reason for apps to do this
// clean-up themselves.
thread.stop();
}
}
}
}
// If thread stopping is enabled, executor threads should have been
// stopped above when the executor was shut down but that depends on the
// thread correctly handling the interrupt. Give all the executor
// threads a few seconds shutdown and if they are still running
// Give threads up to 2 seconds to shutdown
int count = 0;
for (Thread t : executorThreadsToStop) {
while (t.isAlive() && count < 100) {
try {
Thread.sleep(20);
} catch (InterruptedException e) {
// Quit the while loop
break;
}
count++;
}
if (t.isAlive()) {
// This method is deprecated and for good reason. This is
// very risky code but is the only option at this point.
// A *very* good reason for apps to do this clean-up
// themselves.
t.stop();
}
}
}
/*
* Look at a threads stack trace to see if it is a request thread or not. It
* isn't perfect, but it should be good-enough for most cases.
*/
private boolean isRequestThread(Thread thread) {
StackTraceElement[] elements = thread.getStackTrace();
if (elements == null || elements.length == 0) {
// Must have stopped already. Too late to ignore it. Assume not a
// request processing thread.
return false;
}
// Step through the methods in reverse order looking for calls to any
// CoyoteAdapter method. All request threads will have this unless
// Tomcat has been heavily modified - in which case there isn't much we
// can do.
for (int i = 0; i < elements.length; i++) {
StackTraceElement element = elements[elements.length - (i+1)];
if ("org.apache.catalina.connector.CoyoteAdapter".equals(
element.getClassName())) {
return true;
}
}
return false;
}
private void clearReferencesStopTimerThread(Thread thread) {
// Need to get references to:
// in Sun/Oracle JDK:
// - newTasksMayBeScheduled field (in java.util.TimerThread)
// - queue field
// - queue.clear()
// in IBM JDK, Apache Harmony:
// - cancel() method (in java.util.Timer$TimerImpl)
try {
try {
Field newTasksMayBeScheduledField =
thread.getClass().getDeclaredField("newTasksMayBeScheduled");
newTasksMayBeScheduledField.setAccessible(true);
Field queueField = thread.getClass().getDeclaredField("queue");
queueField.setAccessible(true);
Object queue = queueField.get(thread);
Method clearMethod = queue.getClass().getDeclaredMethod("clear");
clearMethod.setAccessible(true);
synchronized(queue) {
newTasksMayBeScheduledField.setBoolean(thread, false);
clearMethod.invoke(queue);
queue.notify(); // In case queue was already empty.
}
}catch (NoSuchFieldException nfe){
Method cancelMethod = thread.getClass().getDeclaredMethod("cancel");
synchronized(thread) {
cancelMethod.setAccessible(true);
cancelMethod.invoke(thread);
}
}
log.error(sm.getString("webappClassLoader.warnTimerThread",
getContextName(), thread.getName()));
} catch (Exception e) {
// So many things to go wrong above...
Throwable t = ExceptionUtils.unwrapInvocationTargetException(e);
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString(
"webappClassLoader.stopTimerThreadFail",
thread.getName(), getContextName()), t);
}
}
private void checkThreadLocalsForLeaks() {
Thread[] threads = getThreads();
try {
// Make the fields in the Thread class that store ThreadLocals
// accessible
Field threadLocalsField =
Thread.class.getDeclaredField("threadLocals");
threadLocalsField.setAccessible(true);
Field inheritableThreadLocalsField =
Thread.class.getDeclaredField("inheritableThreadLocals");
inheritableThreadLocalsField.setAccessible(true);
// Make the underlying array of ThreadLoad.ThreadLocalMap.Entry objects
// accessible
Class tlmClass = Class.forName("java.lang.ThreadLocal$ThreadLocalMap");
Field tableField = tlmClass.getDeclaredField("table");
tableField.setAccessible(true);
Method expungeStaleEntriesMethod = tlmClass.getDeclaredMethod("expungeStaleEntries");
expungeStaleEntriesMethod.setAccessible(true);
for (int i = 0; i < threads.length; i++) {
Object threadLocalMap;
if (threads[i] != null) {
// Clear the first map
threadLocalMap = threadLocalsField.get(threads[i]);
if (null != threadLocalMap){
expungeStaleEntriesMethod.invoke(threadLocalMap);
checkThreadLocalMapForLeaks(threadLocalMap, tableField);
}
// Clear the second map
threadLocalMap =inheritableThreadLocalsField.get(threads[i]);
if (null != threadLocalMap){
expungeStaleEntriesMethod.invoke(threadLocalMap);
checkThreadLocalMapForLeaks(threadLocalMap, tableField);
}
}
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString(
"webappClassLoader.checkThreadLocalsForLeaksFail",
getContextName()), t);
}
}
/**
* Analyzes the given thread local map object. Also pass in the field that
* points to the internal table to save re-calculating it on every
* call to this method.
*/
private void checkThreadLocalMapForLeaks(Object map,
Field internalTableField) throws IllegalAccessException,
NoSuchFieldException {
if (map != null) {
Object[] table = (Object[]) internalTableField.get(map);
if (table != null) {
for (int j =0; j < table.length; j++) {
Object obj = table[j];
if (obj != null) {
boolean potentialLeak = false;
// Check the key
Object key = ((Reference) obj).get();
if (this.equals(key) || loadedByThisOrChild(key)) {
potentialLeak = true;
}
// Check the value
Field valueField =
obj.getClass().getDeclaredField("value");
valueField.setAccessible(true);
Object value = valueField.get(obj);
if (this.equals(value) || loadedByThisOrChild(value)) {
potentialLeak = true;
}
if (potentialLeak) {
Object[] args = new Object[5];
args[0] = getContextName();
if (key != null) {
args[1] = getPrettyClassName(key.getClass());
try {
args[2] = key.toString();
} catch (Exception e) {
log.error(sm.getString(
"webappClassLoader.checkThreadLocalsForLeaks.badKey",
args[1]), e);
args[2] = sm.getString(
"webappClassLoader.checkThreadLocalsForLeaks.unknown");
}
}
if (value != null) {
args[3] = getPrettyClassName(value.getClass());
try {
args[4] = value.toString();
} catch (Exception e) {
log.error(sm.getString(
"webappClassLoader.checkThreadLocalsForLeaks.badValue",
args[3]), e);
args[4] = sm.getString(
"webappClassLoader.checkThreadLocalsForLeaks.unknown");
}
}
if (value == null) {
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"webappClassLoader.checkThreadLocalsForLeaksDebug",
args));
}
} else {
log.error(sm.getString(
"webappClassLoader.checkThreadLocalsForLeaks",
args));
}
}
}
}
}
}
}
private String getPrettyClassName(Class clazz) {
String name = clazz.getCanonicalName();
if (name==null){
name = clazz.getName();
}
return name;
}
/**
* @param o object to test, may be null
* @return true if o has been loaded by the current classloader
* or one of its descendants.
*/
private boolean loadedByThisOrChild(Object o) {
if (o == null) {
return false;
}
Class clazz;
if (o instanceof Class) {
clazz = (Class) o;
} else {
clazz = o.getClass();
}
ClassLoader cl = clazz.getClassLoader();
while (cl != null) {
if (cl == this) {
return true;
}
cl = cl.getParent();
}
if (o instanceof Collection) {
Iterator iter = ((Collection) o).iterator();
try {
while (iter.hasNext()) {
Object entry = iter.next();
if (loadedByThisOrChild(entry)) {
return true;
}
}
} catch (ConcurrentModificationException e) {
log.warn(sm.getString(
"webappClassLoader", clazz.getName(), getContextName()),
e);
}
}
return false;
}
/*
* Get the set of current threads as an array.
*/
private Thread[] getThreads() {
// Get the current thread group
ThreadGroup tg = Thread.currentThread().getThreadGroup();
// Find the root thread group
try {
while (tg.getParent() != null) {
tg = tg.getParent();
}
} catch (SecurityException se) {
String msg = sm.getString(
"webappClassLoader.getThreadGroupError", tg.getName());
if (log.isDebugEnabled()) {
log.debug(msg, se);
} else {
log.warn(msg);
}
}
int threadCountGuess = tg.activeCount() + 50;
Thread[] threads = new Thread[threadCountGuess];
int threadCountActual = tg.enumerate(threads);
// Make sure we don't miss any threads
while (threadCountActual == threadCountGuess) {
threadCountGuess *=2;
threads = new Thread[threadCountGuess];
// Note tg.enumerate(Thread[]) silently ignores any threads that
// can't fit into the array
threadCountActual = tg.enumerate(threads);
}
return threads;
}
/**
* This depends on the internals of the Sun JVM so it does everything by
* reflection.
*/
private void clearReferencesRmiTargets() {
try {
// Need access to the ccl field of sun.rmi.transport.Target
Class objectTargetClass =
Class.forName("sun.rmi.transport.Target");
Field cclField = objectTargetClass.getDeclaredField("ccl");
cclField.setAccessible(true);
// Clear the objTable map
Class objectTableClass =
Class.forName("sun.rmi.transport.ObjectTable");
Field objTableField = objectTableClass.getDeclaredField("objTable");
objTableField.setAccessible(true);
Object objTable = objTableField.get(null);
if (objTable == null) {
return;
}
// Iterate over the values in the table
if (objTable instanceof Map) {
Iterator iter = ((Map) objTable).values().iterator();
while (iter.hasNext()) {
Object obj = iter.next();
Object cclObject = cclField.get(obj);
if (this == cclObject) {
iter.remove();
}
}
}
// Clear the implTable map
Field implTableField = objectTableClass.getDeclaredField("implTable");
implTableField.setAccessible(true);
Object implTable = implTableField.get(null);
if (implTable == null) {
return;
}
// Iterate over the values in the table
if (implTable instanceof Map) {
Iterator iter = ((Map) implTable).values().iterator();
while (iter.hasNext()) {
Object obj = iter.next();
Object cclObject = cclField.get(obj);
if (this == cclObject) {
iter.remove();
}
}
}
} catch (ClassNotFoundException e) {
log.info(sm.getString("webappClassLoader.clearRmiInfo",
getContextName()), e);
} catch (SecurityException e) {
log.warn(sm.getString("webappClassLoader.clearRmiFail",
getContextName()), e);
} catch (NoSuchFieldException e) {
log.warn(sm.getString("webappClassLoader.clearRmiFail",
getContextName()), e);
} catch (IllegalArgumentException e) {
log.warn(sm.getString("webappClassLoader.clearRmiFail",
getContextName()), e);
} catch (IllegalAccessException e) {
log.warn(sm.getString("webappClassLoader.clearRmiFail",
getContextName()), e);
}
}
/**
* Clear the {@link ResourceBundle} cache of any bundles loaded by this
* class loader or any class loader where this loader is a parent class
* loader. Whilst {@link ResourceBundle#clearCache()} could be used there
* are complications around the
* {@link org.apache.jasper.servlet.JasperLoader} that mean a reflection
* based approach is more likely to be complete.
*
* The ResourceBundle is using WeakReferences so it shouldn't be pinning the
* class loader in memory. However, it is. Therefore clear ou the
* references.
*/
private void clearReferencesResourceBundles() {
// Get a reference to the cache
try {
Field cacheListField =
ResourceBundle.class.getDeclaredField("cacheList");
cacheListField.setAccessible(true);
// Java 6 uses ConcurrentMap
// Java 5 uses SoftCache extends Abstract Map
// So use Map and it *should* work with both
Map cacheList = (Map) cacheListField.get(null);
// Get the keys (loader references are in the key)
Set keys = cacheList.keySet();
Field loaderRefField = null;
// Iterate over the keys looking at the loader instances
Iterator keysIter = keys.iterator();
int countRemoved = 0;
while (keysIter.hasNext()) {
Object key = keysIter.next();
if (loaderRefField == null) {
loaderRefField =
key.getClass().getDeclaredField("loaderRef");
loaderRefField.setAccessible(true);
}
WeakReference loaderRef =
(WeakReference) loaderRefField.get(key);
ClassLoader loader = (ClassLoader) loaderRef.get();
while (loader != null && loader != this) {
loader = loader.getParent();
}
if (loader != null) {
keysIter.remove();
countRemoved++;
}
}
if (countRemoved > 0 && log.isDebugEnabled()) {
log.debug(sm.getString(
"webappClassLoader.clearReferencesResourceBundlesCount",
Integer.valueOf(countRemoved), getContextName()));
}
} catch (SecurityException e) {
log.error(sm.getString(
"webappClassLoader.clearReferencesResourceBundlesFail",
getContextName()), e);
} catch (NoSuchFieldException e) {
if (Globals.IS_ORACLE_JVM) {
log.error(sm.getString(
"webappClassLoader.clearReferencesResourceBundlesFail",
getContextName()), e);
} else {
log.debug(sm.getString(
"webappClassLoader.clearReferencesResourceBundlesFail",
getContextName()), e);
}
} catch (IllegalArgumentException e) {
log.error(sm.getString(
"webappClassLoader.clearReferencesResourceBundlesFail",
getContextName()), e);
} catch (IllegalAccessException e) {
log.error(sm.getString(
"webappClassLoader.clearReferencesResourceBundlesFail",
getContextName()), e);
}
}
/**
* Find specified class in local repositories.
*
* @param name The binary name of the class to be loaded
*
* @return the loaded class, or null if the class isn't found
*/
protected Class findClassInternal(String name)
throws ClassNotFoundException {
if (!validate(name))
throw new ClassNotFoundException(name);
String path = binaryNameToPath(name, true);
ResourceEntry entry = null;
if (securityManager != null) {
PrivilegedAction dp =
new PrivilegedFindResourceByName(name, path);
entry = AccessController.doPrivileged(dp);
} else {
entry = findResourceInternal(name, path);
}
if (entry == null)
throw new ClassNotFoundException(name);
Class clazz = entry.loadedClass;
if (clazz != null)
return clazz;
synchronized (this) {
clazz = entry.loadedClass;
if (clazz != null)
return clazz;
if (entry.binaryContent == null)
throw new ClassNotFoundException(name);
// Looking up the package
String packageName = null;
int pos = name.lastIndexOf('.');
if (pos != -1)
packageName = name.substring(0, pos);
Package pkg = null;
if (packageName != null) {
pkg = getPackage(packageName);
// Define the package (if null)
if (pkg == null) {
try {
if (entry.manifest == null) {
definePackage(packageName, null, null, null, null,
null, null, null);
} else {
definePackage(packageName, entry.manifest,
entry.codeBase);
}
} catch (IllegalArgumentException e) {
// Ignore: normal error due to dual definition of package
}
pkg = getPackage(packageName);
}
}
if (securityManager != null) {
// Checking sealing
if (pkg != null) {
boolean sealCheck = true;
if (pkg.isSealed()) {
sealCheck = pkg.isSealed(entry.codeBase);
} else {
sealCheck = (entry.manifest == null)
|| !isPackageSealed(packageName, entry.manifest);
}
if (!sealCheck)
throw new SecurityException
("Sealing violation loading " + name + " : Package "
+ packageName + " is sealed.");
}
}
try {
clazz = defineClass(name, entry.binaryContent, 0,
entry.binaryContent.length,
new CodeSource(entry.codeBase, entry.certificates));
} catch (UnsupportedClassVersionError ucve) {
throw new UnsupportedClassVersionError(
ucve.getLocalizedMessage() + " " +
sm.getString("webappClassLoader.wrongVersion",
name));
}
// Now the class has been defined, clear the elements of the local
// resource cache that are no longer required.
entry.loadedClass = clazz;
entry.binaryContent = null;
entry.codeBase = null;
entry.manifest = null;
entry.certificates = null;
// Retain entry.source in case of a getResourceAsStream() call on
// the class file after the class has been defined.
}
return clazz;
}
private String binaryNameToPath(String binaryName, boolean withLeadingSlash) {
StringBuilder path = new StringBuilder(
1 + binaryName.length() + CLASS_FILE_SUFFIX.length());
if (withLeadingSlash) {
path.append('/');
}
path.append(binaryName.replace('.', '/'));
path.append(CLASS_FILE_SUFFIX);
return path.toString();
}
private String nameToPath(String name) {
if (name.startsWith("/")) {
return name;
}
StringBuilder path = new StringBuilder(
1 + name.length());
path.append('/');
path.append(name);
return path.toString();
}
/**
* Find specified resource in local repositories.
*
* @return the loaded resource, or null if the resource isn't found
*/
protected ResourceEntry findResourceInternal(final String name, final String path) {
if (!started) {
log.info(sm.getString("webappClassLoader.stopped", name));
return null;
}
if ((name == null) || (path == null))
return null;
ResourceEntry entry = resourceEntries.get(path);
if (entry != null)
return entry;
boolean isClassResource = path.endsWith(CLASS_FILE_SUFFIX);
WebResource resource = null;
boolean fileNeedConvert = false;
resource = resources.getClassLoaderResource(path);
if (!resource.exists()) {
return null;
}
entry = new ResourceEntry();
entry.source = resource.getURL();
entry.codeBase = entry.source;
entry.lastModified = resource.getLastModified();
if (needConvert) {
if (path.endsWith(".properties")) {
fileNeedConvert = true;
}
}
/* Only cache the binary content if there is some content
* available and either:
* a) It is a class file since the binary content is only cached
* until the class has been loaded
* or
* b) The file needs conversion to address encoding issues (see
* below)
*
* In all other cases do not cache the content to prevent
* excessive memory usage if large resources are present (see
* https://issues.apache.org/bugzilla/show_bug.cgi?id=53081).
*/
if (isClassResource || fileNeedConvert) {
byte[] binaryContent = resource.getContent();
if (binaryContent != null) {
if (fileNeedConvert) {
// Workaround for certain files on platforms that use
// EBCDIC encoding, when they are read through FileInputStream.
// See commit message of rev.303915 for details
// http://svn.apache.org/viewvc?view=revision&revision=303915
String str = new String(binaryContent);
try {
binaryContent = str.getBytes(StandardCharsets.UTF_8);
} catch (Exception e) {
return null;
}
}
entry.binaryContent = binaryContent;
// The certificates and manifest are made available as a side
// effect of reading the binary content
entry.certificates = resource.getCertificates();
}
}
entry.manifest = resource.getManifest();
if (isClassResource && entry.binaryContent != null &&
this.transformers.size() > 0) {
// If the resource is a class just being loaded, decorate it
// with any attached transformers
String className = name.endsWith(CLASS_FILE_SUFFIX) ?
name.substring(0, name.length() - CLASS_FILE_SUFFIX.length()) : name;
String internalName = className.replace(".", "/");
for (ClassFileTransformer transformer : this.transformers) {
try {
byte[] transformed = transformer.transform(
this, internalName, null, null, entry.binaryContent
);
if (transformed != null) {
entry.binaryContent = transformed;
}
} catch (IllegalClassFormatException e) {
log.error(sm.getString("webappClassLoader.transformError", name), e);
return null;
}
}
}
// Add the entry in the local resource repository
synchronized (resourceEntries) {
// Ensures that all the threads which may be in a race to load
// a particular class all end up with the same ResourceEntry
// instance
ResourceEntry entry2 = resourceEntries.get(path);
if (entry2 == null) {
resourceEntries.put(path, entry);
} else {
entry = entry2;
}
}
return entry;
}
/**
* Returns true if the specified package name is sealed according to the
* given manifest.
*/
protected boolean isPackageSealed(String name, Manifest man) {
String path = name.replace('.', '/') + '/';
Attributes attr = man.getAttributes(path);
String sealed = null;
if (attr != null) {
sealed = attr.getValue(Name.SEALED);
}
if (sealed == null) {
if ((attr = man.getMainAttributes()) != null) {
sealed = attr.getValue(Name.SEALED);
}
}
return "true".equalsIgnoreCase(sealed);
}
/**
* Finds the resource with the given name if it has previously been
* loaded and cached by this class loader, and return an input stream
* to the resource data. If this resource has not been cached, return
* null.
*
* @param name Name of the resource to return
*/
protected InputStream findLoadedResource(String name) {
String path = nameToPath(name);
ResourceEntry entry = resourceEntries.get(path);
if (entry != null) {
if (entry.binaryContent != null)
return new ByteArrayInputStream(entry.binaryContent);
else {
try {
return entry.source.openStream();
} catch (IOException ioe) {
// Ignore
}
}
}
return null;
}
/**
* Finds the class with the given name if it has previously been
* loaded and cached by this class loader, and return the Class object.
* If this class has not been cached, return null.
*
* @param name The binary name of the resource to return
*/
protected Class findLoadedClass0(String name) {
String path = binaryNameToPath(name, true);
ResourceEntry entry = resourceEntries.get(path);
if (entry != null) {
return entry.loadedClass;
}
return null;
}
/**
* Refresh the system policy file, to pick up eventual changes.
*/
protected void refreshPolicy() {
try {
// The policy file may have been modified to adjust
// permissions, so we're reloading it when loading or
// reloading a Context
Policy policy = Policy.getPolicy();
policy.refresh();
} catch (AccessControlException e) {
// Some policy files may restrict this, even for the core,
// so this exception is ignored
}
}
/**
* Filter classes.
*
* @param name class name
* @return true if the class should be filtered
*/
protected synchronized boolean filter(String name) {
if (name == null)
return false;
// Looking up the package
String packageName = null;
int pos = name.lastIndexOf('.');
if (pos != -1)
packageName = name.substring(0, pos);
else
return false;
packageTriggersPermit.reset(packageName);
if (packageTriggersPermit.lookingAt()) {
return false;
}
packageTriggersDeny.reset(packageName);
if (packageTriggersDeny.lookingAt()) {
return true;
}
return false;
}
/**
* Validate a classname. As per SRV.9.7.2, we must restrict loading of
* classes from J2SE (java.*) and most classes of the servlet API
* (javax.servlet.*). That should enhance robustness and prevent a number
* of user error (where an older version of servlet.jar would be present
* in /WEB-INF/lib).
*
* @param name class name
* @return true if the name is valid
*/
protected boolean validate(String name) {
// Need to be careful with order here
if (name == null) {
// Can't load a class without a name
return false;
}
if (name.startsWith("java.")) {
// Must never load java.* classes
return false;
}
if (name.startsWith("javax.servlet.jsp.jstl")) {
// OK for web apps to package JSTL
return true;
}
if (name.startsWith("javax.servlet.")) {
// Web apps should never package any other Servlet or JSP classes
return false;
}
if (name.startsWith("javax.el")) {
// Must never load javax.el.* classes
return false;
}
// Assume everything else is OK
return true;
}
}