| /* |
| * Copyright (c) 2018, 2019, 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 com.sun.jndi.ldap; |
| |
| import java.security.PrivilegedAction; |
| import java.util.*; |
| import javax.naming.NamingException; |
| import com.sun.jndi.ldap.spi.LdapDnsProvider; |
| import com.sun.jndi.ldap.spi.LdapDnsProviderResult; |
| import sun.misc.JavaSecurityAccess; |
| import sun.misc.SharedSecrets; |
| import sun.security.util.SecurityConstants; |
| |
| /** |
| * The {@code LdapDnsProviderService} is responsible for creating and providing |
| * access to the registered {@code LdapDnsProvider}s. The {@link ServiceLoader} |
| * is used to find and register any implementations of {@link LdapDnsProvider}. |
| * |
| * <p> Instances of this class are safe for use by multiple threads. |
| */ |
| final class LdapDnsProviderService { |
| |
| private static volatile LdapDnsProviderService service; |
| private static final Object LOCK = new int[0]; |
| private final ServiceLoader<LdapDnsProvider> providers; |
| |
| /** |
| * Creates a new instance of LdapDnsProviderService |
| */ |
| private LdapDnsProviderService() { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm == null) { |
| providers = ServiceLoader.load( |
| LdapDnsProvider.class, |
| ClassLoader.getSystemClassLoader()); |
| } else { |
| final PrivilegedAction<ServiceLoader<LdapDnsProvider>> pa = |
| new PrivilegedAction<ServiceLoader<LdapDnsProvider>>() { |
| @Override |
| public ServiceLoader<LdapDnsProvider> run() { |
| return ServiceLoader.load( |
| LdapDnsProvider.class, |
| ClassLoader.getSystemClassLoader()); |
| } |
| }; |
| |
| JavaSecurityAccess jsa = SharedSecrets.getJavaSecurityAccess(); |
| providers = jsa.doPrivileged( |
| pa, |
| null, |
| new RuntimePermission("ldapDnsProvider"), |
| SecurityConstants.GET_CLASSLOADER_PERMISSION); |
| } |
| } |
| |
| /** |
| * Retrieves the singleton instance of LdapDnsProviderService. |
| */ |
| static LdapDnsProviderService getInstance() { |
| if (service != null) return service; |
| synchronized (LOCK) { |
| if (service != null) return service; |
| service = new LdapDnsProviderService(); |
| } |
| return service; |
| } |
| |
| /** |
| * Retrieves result from the first provider that successfully resolves |
| * the endpoints. If no results are found when calling installed |
| * subclasses of {@code LdapDnsProvider} then this method will fall back |
| * to the {@code DefaultLdapDnsProvider}. |
| * |
| * @throws NamingException if the {@code url} in not valid or an error |
| * occurred while performing the lookup. |
| */ |
| LdapDnsProviderResult lookupEndpoints(String url, Hashtable<?,?> env) |
| throws NamingException |
| { |
| LdapDnsProviderResult result = null; |
| Hashtable<?, ?> envCopy = new Hashtable<>(env); |
| |
| synchronized (LOCK) { |
| Iterator<LdapDnsProvider> iterator = providers.iterator(); |
| while (result == null && iterator.hasNext()) { |
| result = iterator.next().lookupEndpoints(url, envCopy); |
| if (result != null && result.getEndpoints().isEmpty()) { |
| result = null; |
| } |
| } |
| } |
| |
| if (result == null) { |
| result = new DefaultLdapDnsProvider().lookupEndpoints(url, env); |
| if (result == null) { |
| return new LdapDnsProviderResult("", Collections.<String>emptyList()); |
| } |
| } |
| |
| return result; |
| } |
| |
| } |