--- a/jdk/src/share/classes/java/lang/invoke/MethodHandleImpl.java Wed Sep 19 21:42:21 2012 +0400
+++ b/jdk/src/share/classes/java/lang/invoke/MethodHandleImpl.java Thu Sep 20 14:02:55 2012 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2012, 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
@@ -25,13 +25,14 @@
package java.lang.invoke;
-import sun.invoke.util.VerifyType;
-
+import java.security.AccessController;
+import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import sun.invoke.empty.Empty;
import sun.invoke.util.ValueConversions;
+import sun.invoke.util.VerifyType;
import sun.invoke.util.Wrapper;
import static java.lang.invoke.LambdaForm.*;
import static java.lang.invoke.MethodHandleStatics.*;
@@ -781,4 +782,168 @@
return mh;
}
+ /**
+ * Create an alias for the method handle which, when called,
+ * appears to be called from the same class loader and protection domain
+ * as hostClass.
+ * This is an expensive no-op unless the method which is called
+ * is sensitive to its caller. A small number of system methods
+ * are in this category, including Class.forName and Method.invoke.
+ */
+ static
+ MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
+ return BindCaller.bindCaller(mh, hostClass);
+ }
+
+ // Put the whole mess into its own nested class.
+ // That way we can lazily load the code and set up the constants.
+ private static class BindCaller {
+ static
+ MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
+ // Do not use this function to inject calls into system classes.
+ if (hostClass == null) {
+ hostClass = C_Trampoline;
+ } else if (hostClass.isArray() ||
+ hostClass.isPrimitive() ||
+ hostClass.getName().startsWith("java.") ||
+ hostClass.getName().startsWith("sun.")) {
+ throw new InternalError(); // does not happen, and should not anyway
+ }
+ // For simplicity, convert mh to a varargs-like method.
+ MethodHandle vamh = prepareForInvoker(mh);
+ // Cache the result of makeInjectedInvoker once per argument class.
+ MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
+ return restoreToType(bccInvoker.bindTo(vamh), mh.type());
+ }
+
+ // This class ("Trampoline") is known to be inside a dead-end class loader.
+ // Inject all doubtful calls into this class.
+ private static Class<?> C_Trampoline;
+ static {
+ Class<?> tramp = null;
+ try {
+ final int FRAME_COUNT_ARG = 1; // [0] Reflection [1] Trampoline
+ java.lang.reflect.Method gcc = sun.reflect.Reflection.class.getMethod("getCallerClass", int.class);
+ tramp = (Class<?>) sun.reflect.misc.MethodUtil.invoke(gcc, null, new Object[]{ FRAME_COUNT_ARG });
+ if (tramp.getClassLoader() == BindCaller.class.getClassLoader())
+ throw new RuntimeException(tramp.getName()+" class loader");
+ } catch (Throwable ex) {
+ throw new InternalError(ex);
+ }
+ C_Trampoline = tramp;
+ }
+
+ private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
+ Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
+ if (hostClass.getClassLoader() != bcc.getClassLoader())
+ throw new InternalError(hostClass.getName()+" (CL)");
+ try {
+ if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
+ throw new InternalError(hostClass.getName()+" (PD)");
+ } catch (SecurityException ex) {
+ // Self-check was blocked by security manager. This is OK.
+ // In fact the whole try body could be turned into an assertion.
+ }
+ try {
+ MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
+ init.invokeExact(); // force initialization of the class
+ } catch (Throwable ex) {
+ throw uncaughtException(ex);
+ }
+ MethodHandle bccInvoker;
+ try {
+ MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
+ bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
+ } catch (ReflectiveOperationException ex) {
+ throw uncaughtException(ex);
+ }
+ // Test the invoker, to ensure that it really injects into the right place.
+ try {
+ MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
+ Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
+ } catch (Throwable ex) {
+ throw new InternalError(ex);
+ }
+ return bccInvoker;
+ }
+ private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
+ @Override protected MethodHandle computeValue(Class<?> hostClass) {
+ return makeInjectedInvoker(hostClass);
+ }
+ };
+
+ // Adapt mh so that it can be called directly from an injected invoker:
+ private static MethodHandle prepareForInvoker(MethodHandle mh) {
+ mh = mh.asFixedArity();
+ MethodType mt = mh.type();
+ int arity = mt.parameterCount();
+ MethodHandle vamh = mh.asType(mt.generic());
+ vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
+ vamh = vamh.asSpreader(Object[].class, arity);
+ vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
+ return vamh;
+ }
+
+ // Undo the adapter effect of prepareForInvoker:
+ private static MethodHandle restoreToType(MethodHandle vamh, MethodType type) {
+ return vamh.asCollector(Object[].class, type.parameterCount()).asType(type);
+ }
+
+ private static final MethodHandle MH_checkCallerClass;
+ static {
+ final Class<?> THIS_CLASS = BindCaller.class;
+ assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
+ try {
+ MH_checkCallerClass = IMPL_LOOKUP
+ .findStatic(THIS_CLASS, "checkCallerClass",
+ MethodType.methodType(boolean.class, Class.class, Class.class));
+ assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
+ } catch (Throwable ex) {
+ throw new InternalError(ex);
+ }
+ }
+
+ private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
+ final int FRAME_COUNT_ARG = 2; // [0] Reflection [1] BindCaller [2] Expected
+ Class<?> actual = sun.reflect.Reflection.getCallerClass(FRAME_COUNT_ARG);
+ if (actual != expected && actual != expected2)
+ throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
+ +(expected == expected2 ? "" : ", or else "+expected2.getName()));
+ return true;
+ }
+
+ private static final byte[] T_BYTES;
+ static {
+ final Object[] values = {null};
+ AccessController.doPrivileged(new PrivilegedAction<Void>() {
+ public Void run() {
+ try {
+ Class<T> tClass = T.class;
+ String tName = tClass.getName();
+ String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
+ java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
+ int len = uconn.getContentLength();
+ byte[] bytes = new byte[len];
+ try (java.io.InputStream str = uconn.getInputStream()) {
+ int nr = str.read(bytes);
+ if (nr != len) throw new java.io.IOException(tResource);
+ }
+ values[0] = bytes;
+ } catch (java.io.IOException ex) {
+ throw new InternalError(ex);
+ }
+ return null;
+ }
+ });
+ T_BYTES = (byte[]) values[0];
+ }
+
+ // The following class is used as a template for Unsafe.defineAnonymousClass:
+ private static class T {
+ static void init() { } // side effect: initializes this class
+ static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
+ return vamh.invokeExact(args);
+ }
+ }
+ }
}