1 /*
2 * Copyright (c) 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 import java.io.BufferedInputStream;
26 import java.io.IOException;
27 import java.io.InputStream;
28 import java.util.Map;
29 import java.util.Set;
30 import java.util.Vector;
31 import jdk.internal.org.objectweb.asm.*;
32
33 public class BogoLoader extends ClassLoader {
34
35 static interface VisitorMaker {
36 ClassVisitor make(ClassVisitor visitor);
37 }
38
39
40 /**
41 * Use this property to verify that the desired classloading is happening.
42 */
43 private final boolean verbose = Boolean.getBoolean("bogoloader.verbose");
44 /**
45 * Use this property to disable replacement for testing purposes.
46 */
47 private final boolean noReplace = Boolean.getBoolean("bogoloader.noreplace");
48
49 /**
50 * Set of class names that should be loaded with this loader.
51 * Others are loaded with the system class loader, except for those
52 * that are transformed.
53 */
54 private Set<String> nonSystem;
55
56 /**
57 * Map from class names to a bytecode transformer factory.
58 */
59 private Map<String, VisitorMaker> replaced;
60
61 /**
62 * Keep track (not terribly efficiently) of which classes have already
63 * been loaded by this class loader.
64 */
65 private final Vector<String> history = new Vector<String>();
66
67 private boolean useSystemLoader(String name) {
68 return ! nonSystem.contains(name) && ! replaced.containsKey(name);
69 }
70
71 public BogoLoader(Set<String> non_system, Map<String, VisitorMaker> replaced) {
72 super(Thread.currentThread().getContextClassLoader());
73 this.nonSystem = non_system;
74 this.replaced = replaced;
75 }
76
77 private byte[] readResource(String className) throws IOException {
78 return readResource(className, "class");
79 }
80
81 private byte[] readResource(String className, String suffix) throws IOException {
82 // Note to the unwary -- "/" works on Windows, leave it alone.
83 String fileName = className.replace('.', '/') + "." + suffix;
84 InputStream origStream = getResourceAsStream(fileName);
85 if (origStream == null) {
86 throw new IOException("Resource not found : " + fileName);
87 }
88 BufferedInputStream stream = new java.io.BufferedInputStream(origStream);
89 byte[] data = new byte[stream.available()];
90 int how_many = stream.read(data);
91 // Really ought to deal with the corner cases of stream.available()
92 return data;
93 }
94
95 protected byte[] getClass(String name) throws ClassNotFoundException,
96 IOException {
97 return readResource(name, "class");
98 }
99
100 /**
101 * Loads the named class from the system class loader unless
102 * the name appears in either replaced or nonSystem.
103 * nonSystem classes are loaded into this classloader,
104 * and replaced classes get their content from the specified array
105 * of bytes (and are also loaded into this classloader).
106 */
107 protected Class<?> loadClass(String name, boolean resolve)
108 throws ClassNotFoundException {
109 Class<?> clazz;
110
111 if (history.contains(name)) {
112 Class<?> c = this.findLoadedClass(name);
113 return c;
114 }
115 if (useSystemLoader(name)) {
116 clazz = findSystemClass(name);
117 if (verbose) System.err.println("Loading system class " + name);
118 } else {
119 history.add(name);
120 try {
121 if (verbose) {
122 System.err.println("Loading classloader class " + name);
123 }
124 byte[] classData = getClass(name);;
125 boolean expanded = false;
126 if (!noReplace && replaced.containsKey(name)) {
127 if (verbose) {
128 System.err.println("Replacing class " + name);
129 }
130 ClassReader cr = new ClassReader(classData);
131 ClassWriter cw = new ClassWriter(0);
132 VisitorMaker vm = replaced.get(name);
133 cr.accept(vm.make(cw), 0);
134 classData = cw.toByteArray();
135 }
136 clazz = defineClass(name, classData, 0, classData.length);
137 } catch (java.io.EOFException ioe) {
138 throw new ClassNotFoundException(
139 "IO Exception in reading class : " + name + " ", ioe);
140 } catch (ClassFormatError ioe) {
141 throw new ClassNotFoundException(
142 "ClassFormatError in reading class file: ", ioe);
143 } catch (IOException ioe) {
144 throw new ClassNotFoundException(
145 "IO Exception in reading class file: ", ioe);
146 }
147 }
148 if (clazz == null) {
149 throw new ClassNotFoundException(name);
150 }
151 if (resolve) {
152 resolveClass(clazz);
153 }
154 return clazz;
155 }
156 }