ojluni/src/main/java/sun/reflect/misc/ReflectUtil.java - platform/libcore.git - Git at Google

 /*
  * Copyright (c) 2005, 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
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */


 package sun.reflect.misc;

 import java.lang.reflect.Modifier;
 import java.lang.reflect.Proxy;
 import sun.reflect.Reflection;

 public final class ReflectUtil {

     private ReflectUtil() {
     }

     public static Class forName(String name)
         throws ClassNotFoundException {
         checkPackageAccess(name);
         return Class.forName(name);
     }

     public static Object newInstance(Class cls)
         throws InstantiationException, IllegalAccessException {
         checkPackageAccess(cls);
         return cls.newInstance();
     }

     /*
      * Reflection.ensureMemberAccess is overly-restrictive
      * due to a bug. We awkwardly work around it for now.
      */
     public static void ensureMemberAccess(Class currentClass,
                                           Class memberClass,
                                           Object target,
                                           int modifiers)
         throws IllegalAccessException
     {
         if (target == null && Modifier.isProtected(modifiers)) {
             int mods = modifiers;
             mods = mods & (~Modifier.PROTECTED);
             mods = mods | Modifier.PUBLIC;

             /*
              * See if we fail because of class modifiers
              */
             Reflection.ensureMemberAccess(currentClass,
                                           memberClass,
                                           target,
                                           mods);
             try {
                 /*
                  * We're still here so class access was ok.
                  * Now try with default field access.
                  */
                 mods = mods & (~Modifier.PUBLIC);
                 Reflection.ensureMemberAccess(currentClass,
                                               memberClass,
                                               target,
                                               mods);
                 /*
                  * We're still here so access is ok without
                  * checking for protected.
                  */
                 return;
             } catch (IllegalAccessException e) {
                 /*
                  * Access failed but we're 'protected' so
                  * if the test below succeeds then we're ok.
                  */
                 if (isSubclassOf(currentClass, memberClass)) {
                     return;
                 } else {
                     throw e;
                 }
             }
         } else {
             Reflection.ensureMemberAccess(currentClass,
                                           memberClass,
                                           target,
                                           modifiers);
         }
     }

     private static boolean isSubclassOf(Class queryClass,
                                 Class ofClass)
     {
         while (queryClass != null) {
             if (queryClass == ofClass) {
                 return true;
             }
             queryClass = queryClass.getSuperclass();
         }
         return false;
     }


     /**
      * Checks package access on the given class.
      *
      * If it is a {@link Proxy#isProxyClass(java.lang.Class)} that implements
      * a non-public interface (i.e. may be in a non-restricted package),
      * also check the package access on the proxy interfaces.
      */
     public static void checkPackageAccess(Class<?> clazz) {
         checkPackageAccess(clazz.getName());
         if (isNonPublicProxyClass(clazz)) {
             checkProxyPackageAccess(clazz);
         }
     }

     /**
      * Checks package access on the given classname.
      * This method is typically called when the Class instance is not
      * available and the caller attempts to load a class on behalf
      * the true caller (application).
      */
     public static void checkPackageAccess(String name) {
         SecurityManager s = System.getSecurityManager();
         if (s != null) {
             String cname = name.replace('/', '.');
             if (cname.startsWith("[")) {
                 int b = cname.lastIndexOf('[') + 2;
                 if (b > 1 && b < cname.length()) {
                     cname = cname.substring(b);
                 }
             }
             int i = cname.lastIndexOf('.');
             if (i != -1) {
                 s.checkPackageAccess(cname.substring(0, i));
             }
         }
     }

     public static boolean isPackageAccessible(Class clazz) {
         try {
             checkPackageAccess(clazz);
         } catch (SecurityException e) {
             return false;
         }
         return true;
     }

     // Returns true if p is an ancestor of cl i.e. class loader 'p' can
     // be found in the cl's delegation chain
     private static boolean isAncestor(ClassLoader p, ClassLoader cl) {
         ClassLoader acl = cl;
         do {
             acl = acl.getParent();
             if (p == acl) {
                 return true;
             }
         } while (acl != null);
         return false;
     }

     /**
      * Returns true if package access check is needed for reflective
      * access from a class loader 'from' to classes or members in
      * a class defined by class loader 'to'.  This method returns true
      * if 'from' is not the same as or an ancestor of 'to'.  All code
      * in a system domain are granted with all permission and so this
      * method returns false if 'from' class loader is a class loader
      * loading system classes.  On the other hand, if a class loader
      * attempts to access system domain classes, it requires package
      * access check and this method will return true.
      */
     public static boolean needsPackageAccessCheck(ClassLoader from, ClassLoader to) {
         if (from == null || from == to)
             return false;

         if (to == null)
             return true;

         return !isAncestor(from, to);
     }

     /**
      * Check package access on the proxy interfaces that the given proxy class
      * implements.
      *
      * @param clazz Proxy class object
      */
     public static void checkProxyPackageAccess(Class<?> clazz) {
         SecurityManager s = System.getSecurityManager();
         if (s != null) {
             // check proxy interfaces if the given class is a proxy class
             if (Proxy.isProxyClass(clazz)) {
                 for (Class<?> intf : clazz.getInterfaces()) {
                     checkPackageAccess(intf);
                 }
             }
         }
     }

     /**
      * Access check on the interfaces that a proxy class implements and throw
      * {@code SecurityException} if it accesses a restricted package from
      * the caller's class loader.
      *
      * @param ccl the caller's class loader
      * @param interfaces the list of interfaces that a proxy class implements
      */
     public static void checkProxyPackageAccess(ClassLoader ccl,
                                                Class<?>... interfaces)
     {
         SecurityManager sm = System.getSecurityManager();
         if (sm != null) {
             for (Class<?> intf : interfaces) {
                 ClassLoader cl = intf.getClassLoader();
                 if (needsPackageAccessCheck(ccl, cl)) {
                     checkPackageAccess(intf);
                 }
             }
         }
     }

     public static final String PROXY_PACKAGE = "com.sun.proxy";

     /**
      * Test if the given class is a proxy class that implements
      * non-public interface.  Such proxy class may be in a non-restricted
      * package that bypasses checkPackageAccess.
      */
     public static boolean isNonPublicProxyClass(Class<?> cls) {
         String name = cls.getName();
         int i = name.lastIndexOf('.');
         String pkg = (i != -1) ? name.substring(0, i) : "";
         return Proxy.isProxyClass(cls) && !pkg.equals(PROXY_PACKAGE);
     }
 }
	/*
	* Copyright (c) 2005, 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/


	package sun.reflect.misc;

	import java.lang.reflect.Modifier;
	import java.lang.reflect.Proxy;
	import sun.reflect.Reflection;

	public final class ReflectUtil {

	private ReflectUtil() {
	}

	public static Class forName(String name)
	throws ClassNotFoundException {
	checkPackageAccess(name);
	return Class.forName(name);
	}

	public static Object newInstance(Class cls)
	throws InstantiationException, IllegalAccessException {
	checkPackageAccess(cls);
	return cls.newInstance();
	}

	/*
	* Reflection.ensureMemberAccess is overly-restrictive
	* due to a bug. We awkwardly work around it for now.
	*/
	public static void ensureMemberAccess(Class currentClass,
	Class memberClass,
	Object target,
	int modifiers)
	throws IllegalAccessException
	{
	if (target == null && Modifier.isProtected(modifiers)) {
	int mods = modifiers;
	mods = mods & (~Modifier.PROTECTED);
	mods = mods \| Modifier.PUBLIC;

	/*
	* See if we fail because of class modifiers
	*/
	Reflection.ensureMemberAccess(currentClass,
	memberClass,
	target,
	mods);
	try {
	/*
	* We're still here so class access was ok.
	* Now try with default field access.
	*/
	mods = mods & (~Modifier.PUBLIC);
	Reflection.ensureMemberAccess(currentClass,
	memberClass,
	target,
	mods);
	/*
	* We're still here so access is ok without
	* checking for protected.
	*/
	return;
	} catch (IllegalAccessException e) {
	/*
	* Access failed but we're 'protected' so
	* if the test below succeeds then we're ok.
	*/
	if (isSubclassOf(currentClass, memberClass)) {
	return;
	} else {
	throw e;
	}
	}
	} else {
	Reflection.ensureMemberAccess(currentClass,
	memberClass,
	target,
	modifiers);
	}
	}

	private static boolean isSubclassOf(Class queryClass,
	Class ofClass)
	{
	while (queryClass != null) {
	if (queryClass == ofClass) {
	return true;
	}
	queryClass = queryClass.getSuperclass();
	}
	return false;
	}


	/**
	* Checks package access on the given class.
	*
	* If it is a {@link Proxy#isProxyClass(java.lang.Class)} that implements
	* a non-public interface (i.e. may be in a non-restricted package),
	* also check the package access on the proxy interfaces.
	*/
	public static void checkPackageAccess(Class<?> clazz) {
	checkPackageAccess(clazz.getName());
	if (isNonPublicProxyClass(clazz)) {
	checkProxyPackageAccess(clazz);
	}
	}

	/**
	* Checks package access on the given classname.
	* This method is typically called when the Class instance is not
	* available and the caller attempts to load a class on behalf
	* the true caller (application).
	*/
	public static void checkPackageAccess(String name) {
	SecurityManager s = System.getSecurityManager();
	if (s != null) {
	String cname = name.replace('/', '.');
	if (cname.startsWith("[")) {
	int b = cname.lastIndexOf('[') + 2;
	if (b > 1 && b < cname.length()) {
	cname = cname.substring(b);
	}
	}
	int i = cname.lastIndexOf('.');
	if (i != -1) {
	s.checkPackageAccess(cname.substring(0, i));
	}
	}
	}

	public static boolean isPackageAccessible(Class clazz) {
	try {
	checkPackageAccess(clazz);
	} catch (SecurityException e) {
	return false;
	}
	return true;
	}

	// Returns true if p is an ancestor of cl i.e. class loader 'p' can
	// be found in the cl's delegation chain
	private static boolean isAncestor(ClassLoader p, ClassLoader cl) {
	ClassLoader acl = cl;
	do {
	acl = acl.getParent();
	if (p == acl) {
	return true;
	}
	} while (acl != null);
	return false;
	}

	/**
	* Returns true if package access check is needed for reflective
	* access from a class loader 'from' to classes or members in
	* a class defined by class loader 'to'. This method returns true
	* if 'from' is not the same as or an ancestor of 'to'. All code
	* in a system domain are granted with all permission and so this
	* method returns false if 'from' class loader is a class loader
	* loading system classes. On the other hand, if a class loader
	* attempts to access system domain classes, it requires package
	* access check and this method will return true.
	*/
	public static boolean needsPackageAccessCheck(ClassLoader from, ClassLoader to) {
	if (from == null \|\| from == to)
	return false;

	if (to == null)
	return true;

	return !isAncestor(from, to);
	}

	/**
	* Check package access on the proxy interfaces that the given proxy class
	* implements.
	*
	* @param clazz Proxy class object
	*/
	public static void checkProxyPackageAccess(Class<?> clazz) {
	SecurityManager s = System.getSecurityManager();
	if (s != null) {
	// check proxy interfaces if the given class is a proxy class
	if (Proxy.isProxyClass(clazz)) {
	for (Class<?> intf : clazz.getInterfaces()) {
	checkPackageAccess(intf);
	}
	}
	}
	}

	/**
	* Access check on the interfaces that a proxy class implements and throw
	* {@code SecurityException} if it accesses a restricted package from
	* the caller's class loader.
	*
	* @param ccl the caller's class loader
	* @param interfaces the list of interfaces that a proxy class implements
	*/
	public static void checkProxyPackageAccess(ClassLoader ccl,
	Class<?>... interfaces)
	{
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	for (Class<?> intf : interfaces) {
	ClassLoader cl = intf.getClassLoader();
	if (needsPackageAccessCheck(ccl, cl)) {
	checkPackageAccess(intf);
	}
	}
	}
	}

	public static final String PROXY_PACKAGE = "com.sun.proxy";

	/**
	* Test if the given class is a proxy class that implements
	* non-public interface. Such proxy class may be in a non-restricted
	* package that bypasses checkPackageAccess.
	*/
	public static boolean isNonPublicProxyClass(Class<?> cls) {
	String name = cls.getName();
	int i = name.lastIndexOf('.');
	String pkg = (i != -1) ? name.substring(0, i) : "";
	return Proxy.isProxyClass(cls) && !pkg.equals(PROXY_PACKAGE);
	}
	}