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.security.AccessControlContext;
29 import java.security.AccessController;
30 import java.security.PrivilegedAction;
31 import java.security.ProtectionDomain;
32 import java.security.SecureClassLoader;
33 import java.util.Arrays;
34 import java.util.Collection;
35 import java.util.Collections;
36 import java.util.HashSet;
37 import jdk.internal.dynalink.beans.StaticClass;
38 import jdk.nashorn.internal.codegen.DumpBytecode;
39 import jdk.nashorn.internal.runtime.Context;
40 import jdk.nashorn.internal.runtime.JSType;
41 import jdk.nashorn.internal.runtime.ScriptFunction;
42 import jdk.nashorn.internal.runtime.ScriptObject;
43
44 /**
45 * This class encapsulates the bytecode of the adapter class and can be used to load it into the JVM as an actual Class.
46 * It can be invoked repeatedly to create multiple adapter classes from the same bytecode; adapter classes that have
47 * class-level overrides must be re-created for every set of such overrides. Note that while this class is named
48 * "class loader", it does not, in fact, extend {@code ClassLoader}, but rather uses them internally. Instances of this
49 * class are normally created by {@code JavaAdapterBytecodeGenerator}.
50 */
51 final class JavaAdapterClassLoader {
52 private static final AccessControlContext CREATE_LOADER_ACC_CTXT = ClassAndLoader.createPermAccCtxt("createClassLoader");
53 private static final AccessControlContext GET_CONTEXT_ACC_CTXT = ClassAndLoader.createPermAccCtxt(Context.NASHORN_GET_CONTEXT);
54 private static final Collection<String> VISIBLE_INTERNAL_CLASS_NAMES = Collections.unmodifiableCollection(new HashSet<>(
55 Arrays.asList(JavaAdapterServices.class.getName(), ScriptObject.class.getName(), ScriptFunction.class.getName(), JSType.class.getName())));
56
57 private final String className;
58 private final byte[] classBytes;
59
60 JavaAdapterClassLoader(final String className, final byte[] classBytes) {
61 this.className = className.replace('/', '.');
62 this.classBytes = classBytes;
63 }
64
65 /**
66 * Loads the generated adapter class into the JVM.
67 * @param parentLoader the parent class loader for the generated class loader
68 * @param protectionDomain the protection domain for the generated class
69 * @return the generated adapter class
70 */
71 StaticClass generateClass(final ClassLoader parentLoader, final ProtectionDomain protectionDomain) {
72 assert protectionDomain != null;
73 return AccessController.doPrivileged(new PrivilegedAction<StaticClass>() {
74 @Override
75 public StaticClass run() {
76 try {
77 return StaticClass.forClass(Class.forName(className, true, createClassLoader(parentLoader, protectionDomain)));
78 } catch (final ClassNotFoundException e) {
79 throw new AssertionError(e); // cannot happen
80 }
81 }
82 }, CREATE_LOADER_ACC_CTXT);
83 }
84
85 // Note that the adapter class is created in the protection domain of the class/interface being
86 // extended/implemented, and only the privileged global setter action class is generated in the protection domain
87 // of Nashorn itself. Also note that the creation and loading of the global setter is deferred until it is
88 // required by JVM linker, which will only happen on first invocation of any of the adapted method. We could defer
89 // it even more by separating its invocation into a separate static method on the adapter class, but then someone
90 // with ability to introspect on the class and use setAccessible(true) on it could invoke the method. It's a
91 // security tradeoff...
92 private ClassLoader createClassLoader(final ClassLoader parentLoader, final ProtectionDomain protectionDomain) {
93 return new SecureClassLoader(parentLoader) {
94 private final ClassLoader myLoader = getClass().getClassLoader();
95
96 @Override
97 public Class<?> loadClass(final String name, final boolean resolve) throws ClassNotFoundException {
98 try {
99 Context.checkPackageAccess(name);
100 return super.loadClass(name, resolve);
101 } catch (final SecurityException se) {
102 // we may be implementing an interface or extending a class that was
103 // loaded by a loader that prevents package.access. If so, it'd throw
104 // SecurityException for nashorn's classes!. For adapter's to work, we
105 // should be able to refer to the few classes it needs in its implementation.
106 if(VISIBLE_INTERNAL_CLASS_NAMES.contains(name)) {
107 return myLoader != null? myLoader.loadClass(name) : Class.forName(name, false, myLoader);
108 }
109 throw se;
110 }
111 }
112
113 @Override
114 protected Class<?> findClass(final String name) throws ClassNotFoundException {
115 if(name.equals(className)) {
116 assert classBytes != null : "what? already cleared .class bytes!!";
117
118 final Context ctx = AccessController.doPrivileged(new PrivilegedAction<Context>() {
119 @Override
120 public Context run() {
121 return Context.getContext();
122 }
123 }, GET_CONTEXT_ACC_CTXT);
124 DumpBytecode.dumpBytecode(ctx.getEnv(), ctx.getLogger(jdk.nashorn.internal.codegen.Compiler.class), classBytes, name);
125 return defineClass(name, classBytes, 0, classBytes.length, protectionDomain);
126 }
127 throw new ClassNotFoundException(name);
128 }
129 };
130 }
131 }