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/*
* 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.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.reflect.Method;
import java.security.ProtectionDomain;
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 enum SecuredPrivileged
{
JAVA_9 {
final class ReferencedUnsafe
{
private final SecurityActions.TheUnsafe sunMiscUnsafeTheUnsafe;
private final MethodHandle defineClass;
ReferencedUnsafe(SecurityActions.TheUnsafe usf, MethodHandle meth)
{
this.sunMiscUnsafeTheUnsafe = usf;
this.defineClass = meth;
}
Class<?> defineClass(String name, byte[] b, int off, int len,
ClassLoader loader, ProtectionDomain protectionDomain)
throws ClassFormatError {
if (stack.getCallerClass() != SecuredPrivileged.JAVA_9.getClass())
throw new IllegalAccessError("Access denied for caller.");
try {
return (Class<?>) defineClass.invokeWithArguments(
sunMiscUnsafeTheUnsafe.theUnsafe,
name, b, off, len, loader, protectionDomain);
} catch (Throwable e) {
if (e instanceof RuntimeException) throw (RuntimeException) e;
if (e instanceof ClassFormatError) throw (ClassFormatError) e;
throw new ClassFormatError(e.getMessage());
}
}
}
private final StackWalker stack = StackWalker
.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
private final ReferencedUnsafe sunMiscUnsafe = getReferencedUnsafe();
private final ReferencedUnsafe getReferencedUnsafe()
{
if (null != SecuredPrivileged.JAVA_9
&& stack.getCallerClass() != this.getClass())
throw new IllegalAccessError("Access denied for caller.");
try {
SecurityActions.TheUnsafe usf = SecurityActions.getSunMiscUnsafeAnonymously();
MethodHandle meth = MethodHandles.lookup()
.unreflect(usf.methods.get("defineClass").get(0));
return new ReferencedUnsafe(usf, meth);
} catch (Throwable e) {
throw new RuntimeException("cannot initialize", e);
}
}
@Override
public Class<?> defineClass(String name, byte[] b, int off, int len,
ClassLoader loader, ProtectionDomain protectionDomain)
throws ClassFormatError
{
if (stack.getCallerClass() != DefineClassHelper.class)
throw new IllegalAccessError("Access denied for caller.");
return sunMiscUnsafe.defineClass(name, b, off, len, loader,
protectionDomain);
}
},
JAVA_7 {
private final SecurityActions stack = SecurityActions.stack;
private final MethodHandle defineClass = getDefineClassMethodHandle();
private final MethodHandle getDefineClassMethodHandle()
{
if (null != SecuredPrivileged.JAVA_7
&& stack.getCallerClass() != this.getClass())
throw new IllegalAccessError("Access denied for caller.");
try {
return SecurityActions.getMethodHandle(ClassLoader.class,
"defineClass", new Class[] {
String.class, byte[].class, int.class, int.class,
ProtectionDomain.class
});
} catch (NoSuchMethodException e) {
throw new RuntimeException("cannot initialize", e);
}
}
@Override
protected Class<?> defineClass(String name, byte[] b, int off, int len,
ClassLoader loader, ProtectionDomain protectionDomain) throws ClassFormatError
{
if (stack.getCallerClass() != DefineClassHelper.class)
throw new IllegalAccessError("Access denied for caller.");
try {
return (Class<?>) defineClass.invokeWithArguments(
loader, name, b, off, len, protectionDomain);
} catch (Throwable e) {
if (e instanceof RuntimeException) throw (RuntimeException) e;
if (e instanceof ClassFormatError) throw (ClassFormatError) e;
throw new ClassFormatError(e.getMessage());
}
}
},
JAVA_OTHER {
private final Method defineClass = getDefineClassMethod();
private final SecurityActions stack = SecurityActions.stack;
private final Method getDefineClassMethod() {
if (null != SecuredPrivileged.JAVA_OTHER
&& stack.getCallerClass() != this.getClass())
throw new IllegalAccessError("Access denied for caller.");
try {
return SecurityActions.getDeclaredMethod(ClassLoader.class,
"defineClass", new Class[] {
String.class, byte[].class, int.class, int.class, ProtectionDomain.class
});
} catch (NoSuchMethodException e) {
throw new RuntimeException("cannot initialize", e);
}
}
@Override
protected Class<?> defineClass(String name, byte[] b, int off, int len,
ClassLoader loader, ProtectionDomain protectionDomain) throws ClassFormatError
{
if (stack.getCallerClass() != DefineClassHelper.class)
throw new IllegalAccessError("Access denied for caller.");
try {
SecurityActions.setAccessible(defineClass, true);
return (Class<?>) defineClass.invoke(loader, new Object[] {
name, b, off, len, protectionDomain
});
} catch (Throwable e) {
if (e instanceof ClassFormatError) throw (ClassFormatError) e;
if (e instanceof RuntimeException) throw (RuntimeException) e;
throw new ClassFormatError(e.getMessage());
}
finally {
SecurityActions.setAccessible(defineClass, false);
}
}
};
protected abstract Class<?> defineClass(String name, byte[] b, int off, int len,
ClassLoader loader, ProtectionDomain protectionDomain) throws ClassFormatError;
}
private static final SecuredPrivileged privileged = ClassFile.MAJOR_VERSION >= ClassFile.JAVA_9
? SecuredPrivileged.JAVA_9
: ClassFile.MAJOR_VERSION >= ClassFile.JAVA_7
? SecuredPrivileged.JAVA_7
: SecuredPrivileged.JAVA_OTHER;
/**
* 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
{
try {
return privileged.defineClass(className, bcode, 0, bcode.length, loader, domain);
}
catch (RuntimeException e) {
throw e;
}
catch (ClassFormatError e) {
throw new CannotCompileException(e.getCause());
}
catch (Exception e) {
throw new CannotCompileException(e);
}
}
/**
* 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 DefineClassHelper() {}
}
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