/*
* Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package jdk.internal.reflect;
import java.lang.reflect.*;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import jdk.internal.HotSpotIntrinsicCandidate;
import jdk.internal.misc.VM;
import sun.security.action.GetPropertyAction;
/** Common utility routines used by both java.lang and
java.lang.reflect */
public class Reflection {
/** Used to filter out fields and methods from certain classes from public
view, where they are sensitive or they may contain VM-internal objects.
These Maps are updated very rarely. Rather than synchronize on
each access, we use copy-on-write */
private static volatile Map<Class<?>,String[]> fieldFilterMap;
private static volatile Map<Class<?>,String[]> methodFilterMap;
static {
Map<Class<?>,String[]> map = new HashMap<Class<?>,String[]>();
map.put(Reflection.class,
new String[] {"fieldFilterMap", "methodFilterMap"});
map.put(System.class, new String[] {"security"});
map.put(Class.class, new String[] {"classLoader"});
fieldFilterMap = map;
methodFilterMap = new HashMap<>();
}
/** Returns the class of the caller of the method calling this method,
ignoring frames associated with java.lang.reflect.Method.invoke()
and its implementation. */
@CallerSensitive
@HotSpotIntrinsicCandidate
public static native Class<?> getCallerClass();
/**
* @deprecated This method will be removed.
* This method is a private JDK API and retained temporarily to
* simplify the implementation of sun.misc.Reflection.getCallerClass.
*/
@Deprecated(forRemoval=true)
public static native Class<?> getCallerClass(int depth);
/** Retrieves the access flags written to the class file. For
inner classes these flags may differ from those returned by
Class.getModifiers(), which searches the InnerClasses
attribute to find the source-level access flags. This is used
instead of Class.getModifiers() for run-time access checks due
to compatibility reasons; see 4471811. Only the values of the
low 13 bits (i.e., a mask of 0x1FFF) are guaranteed to be
valid. */
@HotSpotIntrinsicCandidate
public static native int getClassAccessFlags(Class<?> c);
/**
* Ensures that access to a member is granted and throws
* IllegalAccessException if not.
*
* @param currentClass the class performing the access
* @param memberClass the declaring class of the member being accessed
* @param targetClass the class of target object if accessing instance
* field or method;
* or the declaring class if accessing constructor;
* or null if accessing static field or method
* @param modifiers the member's access modifiers
* @throws IllegalAccessException if access to member is denied
*/
public static void ensureMemberAccess(Class<?> currentClass,
Class<?> memberClass,
Class<?> targetClass,
int modifiers)
throws IllegalAccessException
{
if (currentClass == null || memberClass == null) {
throw new InternalError();
}
if (!verifyMemberAccess(currentClass, memberClass, targetClass, modifiers)) {
throwIllegalAccessException(currentClass, memberClass, targetClass, modifiers);
}
}
/**
* Verify access to a member, returning {@code false} if no access
*/
public static boolean verifyMemberAccess(Class<?> currentClass,
Class<?> memberClass,
Class<?> targetClass,
int modifiers)
{
// Verify that currentClass can access a field, method, or
// constructor of memberClass, where that member's access bits are
// "modifiers".
boolean gotIsSameClassPackage = false;
boolean isSameClassPackage = false;
if (currentClass == memberClass) {
// Always succeeds
return true;
}
if (!verifyModuleAccess(currentClass, memberClass)) {
return false;
}
if (!Modifier.isPublic(getClassAccessFlags(memberClass))) {
isSameClassPackage = isSameClassPackage(currentClass, memberClass);
gotIsSameClassPackage = true;
if (!isSameClassPackage) {
return false;
}
}
// At this point we know that currentClass can access memberClass.
if (Modifier.isPublic(modifiers)) {
return true;
}
boolean successSoFar = false;
if (Modifier.isProtected(modifiers)) {
// See if currentClass is a subclass of memberClass
if (isSubclassOf(currentClass, memberClass)) {
successSoFar = true;
}
}
if (!successSoFar && !Modifier.isPrivate(modifiers)) {
if (!gotIsSameClassPackage) {
isSameClassPackage = isSameClassPackage(currentClass,
memberClass);
gotIsSameClassPackage = true;
}
if (isSameClassPackage) {
successSoFar = true;
}
}
if (!successSoFar) {
return false;
}
// Additional test for protected instance members
// and protected constructors: JLS 6.6.2
if (targetClass != null && Modifier.isProtected(modifiers) &&
targetClass != currentClass)
{
if (!gotIsSameClassPackage) {
isSameClassPackage = isSameClassPackage(currentClass, memberClass);
gotIsSameClassPackage = true;
}
if (!isSameClassPackage) {
if (!isSubclassOf(targetClass, currentClass)) {
return false;
}
}
}
return true;
}
/**
* Returns {@code true} if memberClass's's module exports memberClass's
* package to currentClass's module.
*/
public static boolean verifyModuleAccess(Class<?> currentClass,
Class<?> memberClass) {
return verifyModuleAccess(currentClass.getModule(), memberClass);
}
public static boolean verifyModuleAccess(Module currentModule, Class<?> memberClass) {
Module memberModule = memberClass.getModule();
// module may be null during startup (initLevel 0)
if (currentModule == memberModule)
return true; // same module (named or unnamed)
// memberClass may be primitive or array class
Class<?> c = memberClass;
while (c.isArray()) {
c = c.getComponentType();
}
if (c.isPrimitive())
return true;
// check that memberModule exports the package to currentModule
return memberModule.isExported(c.getPackageName(), currentModule);
}
/**
* Returns true if two classes in the same package.
*/
private static boolean isSameClassPackage(Class<?> c1, Class<?> c2) {
if (c1.getClassLoader() != c2.getClassLoader())
return false;
while (c1.isArray())
c1 = c1.getComponentType();
while (c2.isArray())
c2 = c2.getComponentType();
return Objects.equals(c1.getPackageName(), c2.getPackageName());
}
static boolean isSubclassOf(Class<?> queryClass,
Class<?> ofClass)
{
while (queryClass != null) {
if (queryClass == ofClass) {
return true;
}
queryClass = queryClass.getSuperclass();
}
return false;
}
// fieldNames must contain only interned Strings
public static synchronized void registerFieldsToFilter(Class<?> containingClass,
String ... fieldNames) {
fieldFilterMap =
registerFilter(fieldFilterMap, containingClass, fieldNames);
}
// methodNames must contain only interned Strings
public static synchronized void registerMethodsToFilter(Class<?> containingClass,
String ... methodNames) {
methodFilterMap =
registerFilter(methodFilterMap, containingClass, methodNames);
}
private static Map<Class<?>,String[]> registerFilter(Map<Class<?>,String[]> map,
Class<?> containingClass, String ... names) {
if (map.get(containingClass) != null) {
throw new IllegalArgumentException
("Filter already registered: " + containingClass);
}
map = new HashMap<Class<?>,String[]>(map);
map.put(containingClass, names);
return map;
}
public static Field[] filterFields(Class<?> containingClass,
Field[] fields) {
if (fieldFilterMap == null) {
// Bootstrapping
return fields;
}
return (Field[])filter(fields, fieldFilterMap.get(containingClass));
}
public static Method[] filterMethods(Class<?> containingClass, Method[] methods) {
if (methodFilterMap == null) {
// Bootstrapping
return methods;
}
return (Method[])filter(methods, methodFilterMap.get(containingClass));
}
private static Member[] filter(Member[] members, String[] filteredNames) {
if ((filteredNames == null) || (members.length == 0)) {
return members;
}
int numNewMembers = 0;
for (Member member : members) {
boolean shouldSkip = false;
for (String filteredName : filteredNames) {
if (member.getName() == filteredName) {
shouldSkip = true;
break;
}
}
if (!shouldSkip) {
++numNewMembers;
}
}
Member[] newMembers =
(Member[])Array.newInstance(members[0].getClass(), numNewMembers);
int destIdx = 0;
for (Member member : members) {
boolean shouldSkip = false;
for (String filteredName : filteredNames) {
if (member.getName() == filteredName) {
shouldSkip = true;
break;
}
}
if (!shouldSkip) {
newMembers[destIdx++] = member;
}
}
return newMembers;
}
/**
* Tests if the given method is caller-sensitive and the declaring class
* is defined by either the bootstrap class loader or platform class loader.
*/
public static boolean isCallerSensitive(Method m) {
final ClassLoader loader = m.getDeclaringClass().getClassLoader();
if (VM.isSystemDomainLoader(loader) || isExtClassLoader(loader)) {
return m.isAnnotationPresent(CallerSensitive.class);
}
return false;
}
private static boolean isExtClassLoader(ClassLoader loader) {
ClassLoader cl = ClassLoader.getSystemClassLoader();
while (cl != null) {
if (cl.getParent() == null && cl == loader) {
return true;
}
cl = cl.getParent();
}
return false;
}
// true to print a stack trace when IAE is thrown
private static volatile boolean printStackWhenAccessFails;
// true if printStackWhenAccessFails has been initialized
private static volatile boolean printStackWhenAccessFailsSet;
private static void printStackTraceIfNeeded(Throwable e) {
if (!printStackWhenAccessFailsSet && VM.initLevel() >= 1) {
String s = GetPropertyAction.privilegedGetProperty(
"sun.reflect.debugModuleAccessChecks");
printStackWhenAccessFails =
(s != null && !s.equalsIgnoreCase("false"));
printStackWhenAccessFailsSet = true;
}
if (printStackWhenAccessFails) {
e.printStackTrace();
}
}
/**
* Throws IllegalAccessException with the an exception message based on
* the access that is denied.
*/
private static void throwIllegalAccessException(Class<?> currentClass,
Class<?> memberClass,
Object target,
int modifiers)
throws IllegalAccessException
{
String currentSuffix = "";
String memberSuffix = "";
Module m1 = currentClass.getModule();
if (m1.isNamed())
currentSuffix = " (in " + m1 + ")";
Module m2 = memberClass.getModule();
if (m2.isNamed())
memberSuffix = " (in " + m2 + ")";
Class<?> c = memberClass;
while (c.isArray()) {
c = c.getComponentType();
}
String memberPackageName = c.getPackageName();
String msg = currentClass + currentSuffix + " cannot access ";
if (m2.isExported(memberPackageName, m1)) {
// module access okay so include the modifiers in the message
msg += "a member of " + memberClass + memberSuffix +
" with modifiers \"" + Modifier.toString(modifiers) + "\"";
} else {
// module access failed
msg += memberClass + memberSuffix+ " because "
+ m2 + " does not export " + memberPackageName;
if (m2.isNamed()) msg += " to " + m1;
}
throwIllegalAccessException(msg);
}
/**
* Throws IllegalAccessException with the given exception message.
*/
public static void throwIllegalAccessException(String msg)
throws IllegalAccessException
{
IllegalAccessException e = new IllegalAccessException(msg);
printStackTraceIfNeeded(e);
throw e;
}
/**
* Throws InaccessibleObjectException with the given exception message.
*/
public static void throwInaccessibleObjectException(String msg) {
InaccessibleObjectException e = new InaccessibleObjectException(msg);
printStackTraceIfNeeded(e);
throw e;
}
}