| /* |
| * Copyright (c) 2016, 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 jdk.dynalink; |
| |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodHandles.Lookup; |
| import java.util.Objects; |
| |
| /** |
| * Provides security-checked access to a {@code MethodHandles.Lookup} object. |
| * See {@link #getLookup()} for details. |
| */ |
| public class SecureLookupSupplier { |
| /** |
| * The name of a runtime permission required to successfully invoke the |
| * {@link #getLookup()} method. |
| */ |
| public static final String GET_LOOKUP_PERMISSION_NAME = "dynalink.getLookup"; |
| |
| private static final RuntimePermission GET_LOOKUP_PERMISSION = new RuntimePermission(SecureLookupSupplier.GET_LOOKUP_PERMISSION_NAME); |
| |
| private final MethodHandles.Lookup lookup; |
| |
| /** |
| * Creates a new secure lookup supplier, securing the passed lookup. |
| * @param lookup the lookup to secure. Can not be null. |
| * @throws NullPointerException if null is passed. |
| */ |
| public SecureLookupSupplier(final MethodHandles.Lookup lookup) { |
| this.lookup = Objects.requireNonNull(lookup, "lookup"); |
| } |
| |
| /** |
| * Returns the lookup secured by this {@code SecureLookupSupplier}. |
| * @return the lookup secured by this {@code SecureLookupSupplier}. |
| * @throws SecurityException if the secured lookup isn't the |
| * {@link MethodHandles#publicLookup()}, and a security manager is present, |
| * and a check for {@code RuntimePermission("dynalink.getLookup")} fails. |
| */ |
| public final Lookup getLookup() { |
| final SecurityManager sm = System.getSecurityManager(); |
| if (sm != null && lookup != MethodHandles.publicLookup()) { |
| sm.checkPermission(GET_LOOKUP_PERMISSION); |
| } |
| return lookup; |
| } |
| |
| /** |
| * Returns the value of {@link #getLookup()} without a security check. Can |
| * be used by subclasses to access the lookup quickly. |
| * @return same as returned value of {@link #getLookup()}. |
| */ |
| protected final Lookup getLookupPrivileged() { |
| return lookup; |
| } |
| } |