1 /*
2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.nashorn.internal.runtime.linker;
27
28 import java.lang.reflect.InvocationTargetException;
29 import java.lang.reflect.Method;
30 import java.security.AccessControlContext;
31 import java.security.AccessController;
32 import java.security.PrivilegedAction;
33 import java.security.ProtectionDomain;
34 import java.security.SecureClassLoader;
35 import java.util.Arrays;
36 import java.util.Collection;
37 import java.util.Collections;
38 import java.util.HashSet;
39 import java.util.Set;
40 import jdk.dynalink.beans.StaticClass;
41 import jdk.nashorn.internal.codegen.DumpBytecode;
42 import jdk.nashorn.internal.runtime.Context;
43 import jdk.nashorn.internal.runtime.JSType;
44 import jdk.nashorn.internal.runtime.ScriptFunction;
45 import jdk.nashorn.internal.runtime.ScriptObject;
46
47 /**
48 * This class encapsulates the bytecode of the adapter class and can be used to load it into the JVM as an actual Class.
49 * It can be invoked repeatedly to create multiple adapter classes from the same bytecode; adapter classes that have
50 * class-level overrides must be re-created for every set of such overrides. Note that while this class is named
51 * "class loader", it does not, in fact, extend {@code ClassLoader}, but rather uses them internally. Instances of this
52 * class are normally created by {@code JavaAdapterBytecodeGenerator}.
53 */
54 final class JavaAdapterClassLoader {
55 private static final Module NASHORN_MODULE = Context.class.getModule();
56
57 private static final AccessControlContext CREATE_LOADER_ACC_CTXT = ClassAndLoader.createPermAccCtxt("createClassLoader");
58 private static final AccessControlContext GET_CONTEXT_ACC_CTXT = ClassAndLoader.createPermAccCtxt(Context.NASHORN_GET_CONTEXT);
59
60 private static final Collection<String> VISIBLE_INTERNAL_CLASS_NAMES = Collections.unmodifiableCollection(new HashSet<>(
61 Arrays.asList(JavaAdapterServices.class.getName(), ScriptObject.class.getName(), ScriptFunction.class.getName(), JSType.class.getName())));
62
63 private final String className;
64 private final byte[] classBytes;
65
66 JavaAdapterClassLoader(final String className, final byte[] classBytes) {
67 this.className = className.replace('/', '.');
68 this.classBytes = classBytes;
69 }
70
71 /**
72 * Loads the generated adapter class into the JVM.
73 * @param parentLoader the parent class loader for the generated class loader
74 * @param protectionDomain the protection domain for the generated class
75 * @return the generated adapter class
76 */
77 StaticClass generateClass(final ClassLoader parentLoader, final ProtectionDomain protectionDomain) {
78 assert protectionDomain != null;
79 return AccessController.doPrivileged(new PrivilegedAction<StaticClass>() {
80 @Override
81 public StaticClass run() {
82 try {
83 return StaticClass.forClass(Class.forName(className, true, createClassLoader(parentLoader, protectionDomain)));
84 } catch (final ClassNotFoundException e) {
85 throw new AssertionError(e); // cannot happen
86 }
87 }
88 }, CREATE_LOADER_ACC_CTXT);
89 }
90
91 // Note that the adapter class is created in the protection domain of the class/interface being
92 // extended/implemented, and only the privileged global setter action class is generated in the protection domain
93 // of Nashorn itself. Also note that the creation and loading of the global setter is deferred until it is
94 // required by JVM linker, which will only happen on first invocation of any of the adapted method. We could defer
95 // it even more by separating its invocation into a separate static method on the adapter class, but then someone
96 // with ability to introspect on the class and use setAccessible(true) on it could invoke the method. It's a
97 // security tradeoff...
98 private ClassLoader createClassLoader(final ClassLoader parentLoader, final ProtectionDomain protectionDomain) {
99 return new SecureClassLoader(parentLoader) {
100 private final ClassLoader myLoader = getClass().getClassLoader();
101
102 // the unnamed module into which adapter is loaded!
103 private final Module adapterModule = getUnnamedModule();
104
105 {
106 // specific exports from nashorn to the new adapter module
107 NASHORN_MODULE.addExports("jdk.nashorn.internal.runtime", adapterModule);
108 NASHORN_MODULE.addExports("jdk.nashorn.internal.runtime.linker", adapterModule);
109
110 // nashorn should be be able to read methods of classes loaded in adapter module
111 NASHORN_MODULE.addReads(adapterModule);
112 }
113
114 @Override
115 public Class<?> loadClass(final String name, final boolean resolve) throws ClassNotFoundException {
116 try {
117 final int i = name.lastIndexOf('.');
118 if(i != -1){
119 final String pkgName = name.substring(0,i);
120 Context.checkPackageAccess(pkgName);
121 }
122 return super.loadClass(name, resolve);
123 } catch (final SecurityException se) {
124 // we may be implementing an interface or extending a class that was
125 // loaded by a loader that prevents package.access. If so, it'd throw
126 // SecurityException for nashorn's classes!. For adapter's to work, we
127 // should be able to refer to the few classes it needs in its implementation.
128 if(VISIBLE_INTERNAL_CLASS_NAMES.contains(name)) {
129 return myLoader != null? myLoader.loadClass(name) : Class.forName(name, false, myLoader);
130 }
131 throw se;
132 }
133 }
134
135 @Override
136 protected Class<?> findClass(final String name) throws ClassNotFoundException {
137 if(name.equals(className)) {
138 assert classBytes != null : "what? already cleared .class bytes!!";
139
140 final Context ctx = AccessController.doPrivileged(new PrivilegedAction<Context>() {
141 @Override
142 public Context run() {
143 return Context.getContext();
144 }
145 }, GET_CONTEXT_ACC_CTXT);
146 DumpBytecode.dumpBytecode(ctx.getEnv(), ctx.getLogger(jdk.nashorn.internal.codegen.Compiler.class), classBytes, name);
147 return defineClass(name, classBytes, 0, classBytes.length, protectionDomain);
148 }
149 throw new ClassNotFoundException(name);
150 }
151 };
152 }
153 }