org.embulk.deps.SelfContainedJarAwareURLClassLoader Maven / Gradle / Ivy
package org.embulk.deps;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Optional;
import java.util.Vector;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
/**
* Loads classes and resources from self-contained JAR file resources, and a search path with {@link java.net.URLClassLoader}.
*
* JARs files inside the Embulk JAR file are accessed only when the {@link java.net.URLClassLoader} implementation does
* not find the requested resource. In other words, the delegation parent {@code ClassLoader} and a search path processed by
* {@link java.net.URLClassLoader} are always prioritized over self-contained JAR files.
*
* @see Simplify your application delivery with One-JAR
*/
@SuppressWarnings("checkstyle:AbbreviationAsWordInName")
public class SelfContainedJarAwareURLClassLoader extends URLClassLoader {
public SelfContainedJarAwareURLClassLoader(final URL[] urls, final ClassLoader parent, final String selfContainedJarCategory) {
// The delegation parent ClassLoader is processed by the super class URLClassLoader.
super(urls, parent);
this.accessControlContext = AccessController.getContext();
this.selfContainedJarCategory = selfContainedJarCategory;
}
/**
* Finds the class with the specified binary name.
*
*
It should not be called when the class has already been loaded. The default {@code loadClass} checks
* if the class has already been loaded before calling {@code findClass}.
*/
@Override
protected Class findClass(final String className) throws ClassNotFoundException {
try {
// super.findClass(className) finds both from the delegation parent ClassLoader and non-self-contained JARs.
return super.findClass(className);
} catch (final ClassNotFoundException ignored) {
// Pass through intentionally. Try finding from self-contained JARs.
}
// Try finding from self-contained JARs only when not found from the parent ClassLoader nor filesystem JARs.
try {
return AccessController.doPrivileged(
new PrivilegedExceptionAction>() {
@Override
public Class run() throws ClassNotFoundException {
try {
return defineClassFromEmbulkSelfContainedJarFiles(className);
} catch (final ClassNotFoundException | LinkageError | ClassCastException ex) {
throw ex;
} catch (final Throwable ex) {
// Found a resource in the container JAR, but failed to load it as a class.
throw new ClassNotFoundException(className, ex);
}
}
},
this.accessControlContext);
} catch (final PrivilegedActionException ex) {
final Throwable internalException = ex.getException();
if (internalException instanceof ClassNotFoundException) {
throw (ClassNotFoundException) internalException;
}
if (internalException instanceof LinkageError) {
throw (LinkageError) internalException;
}
if (internalException instanceof ClassCastException) {
throw (ClassCastException) internalException;
}
throw new ClassNotFoundException(className, ex);
}
}
// "protected String findLibrary(String name)" is not overridden because Embulk does not assume native libraries.
// TODO: (maybe) Override "loadClass" so that it can deal with the context class loader.
// Refer to {@link com.simontuffs.onejar.JarClassLoader#loadClass}.
// TODO: (maybe) Override "getResource" so that it can delegate to external class loader explicitly.
// Refer to {@link com.simontuffs.onejar.JarClassLoader#getResource}.
/**
* Finds a resource recognized as the given name.
*
* Resources found by the delegation parent {@link java.net.URLClassLoader} are always prioritized. Resources in
* self-contained JAR file resources are looked into only when not found by the delegation parent {@code URLClassLoader}.
*
*
Note that {@link java.net.URLClassLoader#findResource} is public while {@link java.lang.ClassLoader#findResource}
* is protected.
*
* @param resourceName name of target resource
* @return URL of the resource
*/
@Override
public URL findResource(final String resourceName) {
// super.findResource(resourceName) finds both from the delegation parent ClassLoader and non-self-contained JARs.
final URL resourceUrlFromSuper = super.findResource(resourceName);
if (resourceUrlFromSuper != null) {
return resourceUrlFromSuper;
}
if (this.selfContainedJarCategory != null) {
// TODO: Consider duplicated resources.
final Resource resource = EmbulkSelfContainedJarFiles.getSingleResource(resourceName, this.selfContainedJarCategory);
if (resource == null) {
return null;
}
try {
return AccessController.doPrivileged(new PrivilegedExceptionAction() {
@Override
public URL run() throws MalformedURLException {
return resource.buildJarEmbeddedUrl();
}
}, this.accessControlContext);
} catch (final PrivilegedActionException ignored) {
// Pass through intentionally.
}
}
return null;
}
/**
* Finds resources recognized as the given name.
*
* Note that {@link java.net.URLClassLoader#findResources} is public while {@link java.lang.ClassLoader#findResources}
* is protected.
*/
@Override
public Enumeration findResources(final String resourceName) throws IOException {
// super.findResources(resourceName) finds both from the delegation parent ClassLoader and non-self-contained JARs.
final Enumeration resourceUrlsFromSuper = super.findResources(resourceName);
final Vector resourceUrls = new Vector();
while (resourceUrlsFromSuper.hasMoreElements()) {
resourceUrls.add(resourceUrlsFromSuper.nextElement());
}
if (this.selfContainedJarCategory != null) {
// Even if some resources are found from the delegation parent class loader, it looks into self-contained JAR files.
final Collection resources =
EmbulkSelfContainedJarFiles.getMultipleResources(resourceName, this.selfContainedJarCategory);
final Collection resourceUrlsFromSelfContainedJarFiles;
try {
resourceUrlsFromSelfContainedJarFiles =
AccessController.doPrivileged(new PrivilegedExceptionAction>() {
@Override
public Collection run() throws IOException {
final ArrayList urls = new ArrayList<>();
for (final Resource resource : resources) {
urls.add(resource.buildJarEmbeddedUrl());
}
return urls;
}
},
accessControlContext);
} catch (final PrivilegedActionException ignored) {
// Passing through intentionally.
return resourceUrls.elements();
}
resourceUrls.addAll(resourceUrlsFromSelfContainedJarFiles);
}
return resourceUrls.elements();
}
private Class defineClassFromEmbulkSelfContainedJarFiles(final String className) throws ClassNotFoundException {
if (this.selfContainedJarCategory == null) {
throw new ClassNotFoundException(className);
}
final String resourceName = className.replace('.', '/').concat(".class");
// Class must be singular.
final Resource resource = EmbulkSelfContainedJarFiles.getSingleResource(resourceName, this.selfContainedJarCategory);
if (resource == null) {
throw new ClassNotFoundException(className);
}
final URL codeSourceUrl = resource.getCodeSourceUrl();
final int indexLastPeriod = className.lastIndexOf('.');
if (indexLastPeriod != -1) { // If |className| has a package part.
final String packageName = className.substring(0, indexLastPeriod);
final Manifest manifest = resource.getManifest(); // Class must be singular.
if (!this.checkPackageSealing(packageName, manifest, codeSourceUrl)) {
try {
if (manifest != null) {
this.definePackageFromManifest(packageName, manifest, codeSourceUrl);
} else {
this.definePackage(packageName, null, null, null, null, null, null, null);
}
} catch (final IllegalArgumentException ex) {
if (!this.checkPackageSealing(packageName, manifest, codeSourceUrl)) {
throw new ClassNotFoundException(
"FATAL: Unexpected double failures to define package: " + packageName, ex);
}
}
}
}
final CodeSource codeSource = new CodeSource(codeSourceUrl, resource.getCodeSigners());
return this.defineClass(className, resource.getAdjustedByteBuffer(), codeSource);
}
private boolean checkPackageSealing(final String packageName, final Manifest manifest, final URL url) {
final Package packageInstance = this.getPackage(packageName);
if (packageInstance == null) {
return false;
}
if (packageInstance.isSealed()) {
if (!packageInstance.isSealed(url)) {
throw new SecurityException(String.format(
"Package \"%s\" is already loaded, and sealed with a different code source URL.", packageName));
}
} else {
if ((manifest != null) && isManifestToSeal(packageName, manifest)) {
throw new SecurityException(String.format(
"Package \"%s\" is already loaded, and unsealed.", packageName));
}
}
return true;
}
private static boolean isManifestToSeal(final String packageName, final Manifest manifest) {
final Optional perEntryAttributes =
Optional.ofNullable(manifest.getAttributes(packageName.replace('.', '/').concat("/")));
final Attributes mainAttributes = manifest.getMainAttributes();
return "true".equalsIgnoreCase(
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.SEALED));
}
private Package definePackageFromManifest(final String packageName, final Manifest manifest, final URL codeSourceUrl)
throws IllegalArgumentException {
// https://docs.oracle.com/javase/8/docs/technotes/guides/jar/jar.html#Per-Entry_Attributes
final Optional perEntryAttributes =
Optional.ofNullable(manifest.getAttributes(packageName.replace('.', '/').concat("/")));
final Attributes mainAttributes = manifest.getMainAttributes();
return this.definePackage(
packageName,
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.SPECIFICATION_TITLE),
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.SPECIFICATION_VERSION),
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.SPECIFICATION_VENDOR),
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.IMPLEMENTATION_TITLE),
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.IMPLEMENTATION_VERSION),
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.IMPLEMENTATION_VENDOR),
"true".equalsIgnoreCase(
getEffectiveAttribute(mainAttributes, perEntryAttributes, Attributes.Name.SEALED))
? codeSourceUrl
: null);
}
private static String getEffectiveAttribute(
final Attributes mainAttributes,
final Optional perEntryAttributes,
final Attributes.Name attributeName) {
final String mainAttribute = mainAttributes.getValue(attributeName);
return (String) perEntryAttributes.orElse(mainAttributes).getOrDefault(attributeName, mainAttribute);
}
private final AccessControlContext accessControlContext;
private final String selfContainedJarCategory;
}