--- a/jdk/src/share/classes/sun/dyn/anon/AnonymousClassLoader.java Wed Jul 05 17:38:31 2017 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,290 +0,0 @@
-/*
- * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation. Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code 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 General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-package sun.dyn.anon;
-
-import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import sun.misc.IOUtils;
-
-/**
- * Anonymous class loader. Will load any valid classfile, producing
- * a {@link Class} metaobject, without installing that class in the
- * system dictionary. Therefore, {@link Class#forName(String)} will never
- * produce a reference to an anonymous class.
- * <p>
- * The access permissions of the anonymous class are borrowed from
- * a <em>host class</em>. The new class behaves as if it were an
- * inner class of the host class. It can access the host's private
- * members, if the creator of the class loader has permission to
- * do so (or to create accessible reflective objects).
- * <p>
- * When the anonymous class is loaded, elements of its constant pool
- * can be patched to new values. This provides a hook to pre-resolve
- * named classes in the constant pool to other classes, including
- * anonymous ones. Also, string constants can be pre-resolved to
- * any reference. (The verifier treats non-string, non-class reference
- * constants as plain objects.)
- * <p>
- * Why include the patching function? It makes some use cases much easier.
- * Second, the constant pool needed some internal patching anyway,
- * to anonymize the loaded class itself. Finally, if you are going
- * to use this seriously, you'll want to build anonymous classes
- * on top of pre-existing anonymous classes, and that requires patching.
- *
- * <p>%%% TO-DO:
- * <ul>
- * <li>needs better documentation</li>
- * <li>needs more security work (for safe delegation)</li>
- * <li>needs a clearer story about error processing</li>
- * <li>patch member references also (use ';' as delimiter char)</li>
- * <li>patch method references to (conforming) method handles</li>
- * </ul>
- *
- * @author jrose
- * @author Remi Forax
- * @see <a href="http://blogs.sun.com/jrose/entry/anonymous_classes_in_the_vm">
- * http://blogs.sun.com/jrose/entry/anonymous_classes_in_the_vm</a>
- */
-
-public class AnonymousClassLoader {
- final Class<?> hostClass;
-
- // Note: Do not refactor the calls to checkHostClass unless you
- // also adjust this constant:
- private static int CHC_CALLERS = 3;
-
- public AnonymousClassLoader() {
- this.hostClass = checkHostClass(null);
- }
- public AnonymousClassLoader(Class<?> hostClass) {
- this.hostClass = checkHostClass(hostClass);
- }
-
- private static Class<?> getTopLevelClass(Class<?> clazz) {
- for(Class<?> outer = clazz.getDeclaringClass(); outer != null;
- outer = outer.getDeclaringClass()) {
- clazz = outer;
- }
- return clazz;
- }
-
- private static Class<?> checkHostClass(Class<?> hostClass) {
- // called only from the constructor
- // does a context-sensitive check on caller class
- // CC[0..3] = {Reflection, this.checkHostClass, this.<init>, caller}
- Class<?> caller = sun.reflect.Reflection.getCallerClass(CHC_CALLERS);
-
- if (caller == null) {
- // called from the JVM directly
- if (hostClass == null)
- return AnonymousClassLoader.class; // anything central will do
- return hostClass;
- }
-
- if (hostClass == null)
- hostClass = caller; // default value is caller itself
-
- // anonymous class will access hostClass on behalf of caller
- Class<?> callee = hostClass;
-
- if (caller == callee)
- // caller can always nominate itself to grant caller's own access rights
- return hostClass;
-
- // normalize caller and callee to their top-level classes:
- caller = getTopLevelClass(caller);
- callee = getTopLevelClass(callee);
- if (caller == callee)
- return caller;
-
- ClassLoader callerCL = caller.getClassLoader();
- if (callerCL == null) {
- // caller is trusted code, so accept the proposed hostClass
- return hostClass;
- }
-
- // %%% should do something with doPrivileged, because trusted
- // code should have a way to execute on behalf of
- // partially-trusted clients
-
- // Does the caller have the right to access the private
- // members of the callee? If not, raise an error.
- final int ACC_PRIVATE = 2;
- try {
- sun.reflect.Reflection.ensureMemberAccess(caller, callee, null, ACC_PRIVATE);
- } catch (IllegalAccessException ee) {
- throw new IllegalArgumentException(ee);
- }
-
- return hostClass;
- }
-
- public Class<?> loadClass(byte[] classFile) {
- if (defineAnonymousClass == null) {
- // no JVM support; try to fake an approximation
- try {
- return fakeLoadClass(new ConstantPoolParser(classFile).createPatch());
- } catch (InvalidConstantPoolFormatException ee) {
- throw new IllegalArgumentException(ee);
- }
- }
- return loadClass(classFile, null);
- }
-
- public Class<?> loadClass(ConstantPoolPatch classPatch) {
- if (defineAnonymousClass == null) {
- // no JVM support; try to fake an approximation
- return fakeLoadClass(classPatch);
- }
- Object[] patches = classPatch.patchArray;
- // Convert class names (this late in the game)
- // to use slash '/' instead of dot '.'.
- // Java likes dots, but the JVM likes slashes.
- for (int i = 0; i < patches.length; i++) {
- Object value = patches[i];
- if (value != null) {
- byte tag = classPatch.getTag(i);
- switch (tag) {
- case ConstantPoolVisitor.CONSTANT_Class:
- if (value instanceof String) {
- if (patches == classPatch.patchArray)
- patches = patches.clone();
- patches[i] = ((String)value).replace('.', '/');
- }
- break;
- case ConstantPoolVisitor.CONSTANT_Fieldref:
- case ConstantPoolVisitor.CONSTANT_Methodref:
- case ConstantPoolVisitor.CONSTANT_InterfaceMethodref:
- case ConstantPoolVisitor.CONSTANT_NameAndType:
- // When/if the JVM supports these patches,
- // we'll probably need to reformat them also.
- // Meanwhile, let the class loader create the error.
- break;
- }
- }
- }
- return loadClass(classPatch.outer.classFile, classPatch.patchArray);
- }
-
- private Class<?> loadClass(byte[] classFile, Object[] patchArray) {
- try {
- return (Class<?>)
- defineAnonymousClass.invoke(unsafe,
- hostClass, classFile, patchArray);
- } catch (Exception ex) {
- throwReflectedException(ex);
- throw new RuntimeException("error loading into "+hostClass, ex);
- }
- }
-
- private static void throwReflectedException(Exception ex) {
- if (ex instanceof InvocationTargetException) {
- Throwable tex = ((InvocationTargetException)ex).getTargetException();
- if (tex instanceof Error)
- throw (Error) tex;
- ex = (Exception) tex;
- }
- if (ex instanceof RuntimeException) {
- throw (RuntimeException) ex;
- }
- }
-
- private Class<?> fakeLoadClass(ConstantPoolPatch classPatch) {
- // Implementation:
- // 1. Make up a new name nobody has used yet.
- // 2. Inspect the tail-header of the class to find the this_class index.
- // 3. Patch the CONSTANT_Class for this_class to the new name.
- // 4. Add other CP entries required by (e.g.) string patches.
- // 5. Flatten Class constants down to their names, making sure that
- // the host class loader can pick them up again accurately.
- // 6. Generate the edited class file bytes.
- //
- // Potential limitations:
- // * The class won't be truly anonymous, and may interfere with others.
- // * Flattened class constants might not work, because of loader issues.
- // * Pseudo-string constants will not flatten down to real strings.
- // * Method handles will (of course) fail to flatten to linkage strings.
- if (true) throw new UnsupportedOperationException("NYI");
- Object[] cpArray;
- try {
- cpArray = classPatch.getOriginalCP();
- } catch (InvalidConstantPoolFormatException ex) {
- throw new RuntimeException(ex);
- }
- int thisClassIndex = classPatch.getParser().getThisClassIndex();
- String thisClassName = (String) cpArray[thisClassIndex];
- synchronized (AnonymousClassLoader.class) {
- thisClassName = thisClassName+"\\|"+(++fakeNameCounter);
- }
- classPatch.putUTF8(thisClassIndex, thisClassName);
- byte[] classFile = null;
- return unsafe.defineClass(null, classFile, 0, classFile.length,
- hostClass.getClassLoader(),
- hostClass.getProtectionDomain());
- }
- private static int fakeNameCounter = 99999;
-
- // ignore two warnings on this line:
- static sun.misc.Unsafe unsafe = sun.misc.Unsafe.getUnsafe();
- // preceding line requires that this class be on the boot class path
-
- static private final Method defineAnonymousClass;
- static {
- Method dac = null;
- Class<? extends sun.misc.Unsafe> unsafeClass = unsafe.getClass();
- try {
- dac = unsafeClass.getMethod("defineAnonymousClass",
- Class.class,
- byte[].class,
- Object[].class);
- } catch (Exception ee) {
- dac = null;
- }
- defineAnonymousClass = dac;
- }
-
- private static void noJVMSupport() {
- throw new UnsupportedOperationException("no JVM support for anonymous classes");
- }
-
-
- private static native Class<?> loadClassInternal(Class<?> hostClass,
- byte[] classFile,
- Object[] patchArray);
-
- public static byte[] readClassFile(Class<?> templateClass) throws IOException {
- String templateName = templateClass.getName();
- int lastDot = templateName.lastIndexOf('.');
- java.net.URL url = templateClass.getResource(templateName.substring(lastDot+1)+".class");
- java.net.URLConnection connection = url.openConnection();
- int contentLength = connection.getContentLength();
- if (contentLength < 0)
- throw new IOException("invalid content length "+contentLength);
-
- return IOUtils.readFully(connection.getInputStream(), contentLength, true);
- }
-}