1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.util.proxy;
import java.io.IOException;
import java.lang.reflect.Method;
import java.lang.reflect.Field;
import java.security.ProtectionDomain;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import sun.misc.Unsafe;
import javassist.CannotCompileException;
import javassist.bytecode.ClassFile;
/**
* Helper class for invoking {@link ClassLoader#defineClass(String,byte[],int,int)}.
*
* @since 3.22
*/
public class DefineClassHelper {
private static java.lang.reflect.Method defineClass1 = null;
private static java.lang.reflect.Method defineClass2 = null;
private static Unsafe sunMiscUnsafe = null;
static {
if (ClassFile.MAJOR_VERSION < ClassFile.JAVA_9)
try {
Class<?> cl = Class.forName("java.lang.ClassLoader");
defineClass1 = SecurityActions.getDeclaredMethod(
cl,
"defineClass",
new Class[] { String.class, byte[].class,
int.class, int.class });
defineClass2 = SecurityActions.getDeclaredMethod(
cl,
"defineClass",
new Class[] { String.class, byte[].class,
int.class, int.class, ProtectionDomain.class });
}
catch (Exception e) {
throw new RuntimeException("cannot initialize");
}
else
try {
Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
theUnsafe.setAccessible(true);
sunMiscUnsafe = (sun.misc.Unsafe)theUnsafe.get(null);
}
catch (Throwable t) {}
}
/**
* Loads a class file by a given class loader.
*
* <p>This first tries to use {@code sun.misc.Unsafe} to load a class.
* Then it tries to use a {@code protected} method in {@code java.lang.ClassLoader}
* via {@code PrivilegedAction}. Since the latter approach is not available
* any longer by default in Java 9 or later, the JVM argument
* {@code --add-opens java.base/java.lang=ALL-UNNAMED} must be given to the JVM.
* If this JVM argument cannot be given, {@link #toPublicClass(String,byte[])}
* should be used instead.
* </p>
*
* @param domain if it is null, a default domain is used.
* @since 3.22
*/
public static Class<?> toClass(String className, ClassLoader loader,
ProtectionDomain domain, byte[] bcode)
throws CannotCompileException
{
if (ClassFile.MAJOR_VERSION >= ClassFile.JAVA_9)
if (sunMiscUnsafe != null)
try {
return sunMiscUnsafe.defineClass(className, bcode, 0, bcode.length,
loader, domain);
}
catch (Throwable t2) {}
return toClass2(className, loader, domain, bcode);
}
/**
* Loads a class file by {@code java.lang.invoke.MethodHandles.Lookup}.
*
* @since 3.22
*/
static Class<?> toPublicClass(String className, byte[] bcode)
throws CannotCompileException
{
try {
Lookup lookup = MethodHandles.lookup();
lookup = lookup.dropLookupMode(java.lang.invoke.MethodHandles.Lookup.PRIVATE);
return lookup.defineClass(bcode);
}
catch (Throwable t) {
throw new CannotCompileException(t);
}
}
private static Class<?> toClass2(String cname, ClassLoader loader,
ProtectionDomain domain, byte[] bcode)
throws CannotCompileException
{
try {
Method method;
Object[] args;
if (domain == null) {
method = defineClass1;
args = new Object[] { cname, bcode, Integer.valueOf(0),
Integer.valueOf(bcode.length) };
}
else {
method = defineClass2;
args = new Object[] { cname, bcode, Integer.valueOf(0),
Integer.valueOf(bcode.length), domain };
}
return toClass3(method, loader, args);
}
catch (RuntimeException e) {
throw e;
}
catch (java.lang.reflect.InvocationTargetException e) {
throw new CannotCompileException(e.getTargetException());
}
catch (Exception e) {
throw new CannotCompileException(e);
}
}
private static synchronized
Class<?> toClass3(Method method, ClassLoader loader, Object[] args)
throws Exception
{
SecurityActions.setAccessible(method, true);
Class<?> clazz = (Class<?>)method.invoke(loader, args);
SecurityActions.setAccessible(method, false);
return clazz;
}
}
|
