| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.shiro; |
| |
| import org.apache.shiro.mgt.SecurityManager; |
| import org.apache.shiro.mgt.WrappedSecurityManager; |
| import org.apache.shiro.subject.Subject; |
| import org.apache.shiro.util.ThreadContext; |
| import java.util.Objects; |
| import java.util.function.Predicate; |
| |
| |
| /** |
| * Accesses the currently accessible {@code Subject} for the calling code depending on runtime environment. |
| * |
| * @since 0.2 |
| */ |
| public abstract class SecurityUtils { |
| |
| /** |
| * ONLY used as a 'backup' in VM Singleton environments (that is, standalone environments), since the |
| * ThreadContext should always be the primary source for Subject instances when possible. |
| */ |
| private static volatile SecurityManager securityManager; |
| |
| /** |
| * Returns the currently accessible {@code Subject} available to the calling code depending on |
| * runtime environment. |
| * <p/> |
| * This method is provided as a way of obtaining a {@code Subject} without having to resort to |
| * implementation-specific methods. It also allows the Shiro team to change the underlying implementation of |
| * this method in the future depending on requirements/updates without affecting your code that uses it. |
| * |
| * @return the currently accessible {@code Subject} accessible to the calling code. |
| * @throws IllegalStateException if no {@link Subject Subject} instance or |
| * {@link SecurityManager SecurityManager} instance is available with which to obtain |
| * a {@code Subject}, which which is considered an invalid application configuration |
| * - a Subject should <em>always</em> be available to the caller. |
| */ |
| public static Subject getSubject() { |
| Subject subject = ThreadContext.getSubject(); |
| if (subject == null) { |
| subject = (new Subject.Builder()).buildSubject(); |
| ThreadContext.bind(subject); |
| } |
| return subject; |
| } |
| |
| /** |
| * Sets a VM (static) singleton SecurityManager, specifically for transparent use in the |
| * {@link #getSubject() getSubject()} implementation. |
| * <p/> |
| * <b>This method call exists mainly for framework development support. Application developers should rarely, |
| * if ever, need to call this method.</b> |
| * <p/> |
| * The Shiro development team prefers that SecurityManager instances are non-static application singletons |
| * and <em>not</em> VM static singletons. Application singletons that do not use static memory require some sort |
| * of application configuration framework to maintain the application-wide SecurityManager instance for you |
| * (for example, Spring or EJB3 environments) such that the object reference does not need to be static. |
| * <p/> |
| * In these environments, Shiro acquires Subject data based on the currently executing Thread via its own |
| * framework integration code, and this is the preferred way to use Shiro. |
| * <p/> |
| * However in some environments, such as a standalone desktop application or Applets that do not use Spring or |
| * EJB or similar config frameworks, a VM-singleton might make more sense (although the former is still preferred). |
| * In these environments, setting the SecurityManager via this method will automatically enable the |
| * {@link #getSubject() getSubject()} call to function with little configuration. |
| * <p/> |
| * For example, in these environments, this will work: |
| * <pre> |
| * DefaultSecurityManager securityManager = new {@link org.apache.shiro.mgt.DefaultSecurityManager DefaultSecurityManager}(); |
| * securityManager.setRealms( ... ); //one or more Realms |
| * <b>SecurityUtils.setSecurityManager( securityManager );</b></pre> |
| * <p/> |
| * And then anywhere in the application code, the following call will return the application's Subject: |
| * <pre> |
| * Subject currentUser = SecurityUtils.getSubject();</pre> |
| * |
| * @param securityManager the securityManager instance to set as a VM static singleton. |
| */ |
| public static void setSecurityManager(SecurityManager securityManager) { |
| SecurityUtils.securityManager = securityManager; |
| } |
| |
| /** |
| * Returns the SecurityManager accessible to the calling code. |
| * <p/> |
| * This implementation favors acquiring a thread-bound {@code SecurityManager} if it can find one. If one is |
| * not available to the executing thread, it will attempt to use the static singleton if available (see the |
| * {@link #setSecurityManager setSecurityManager} method for more on the static singleton). |
| * <p/> |
| * If neither the thread-local or static singleton instances are available, this method throws an |
| * {@code UnavailableSecurityManagerException} to indicate an error - a SecurityManager should always be accessible |
| * to calling code in an application. If it is not, it is likely due to a Shiro configuration problem. |
| * |
| * @return the SecurityManager accessible to the calling code. |
| * @throws UnavailableSecurityManagerException if there is no {@code SecurityManager} instance available to the |
| * calling code, which typically indicates an invalid application configuration. |
| */ |
| public static SecurityManager getSecurityManager() throws UnavailableSecurityManagerException { |
| SecurityManager securityManager = ThreadContext.getSecurityManager(); |
| if (securityManager == null) { |
| securityManager = SecurityUtils.securityManager; |
| } |
| if (securityManager == null) { |
| String msg = "No SecurityManager accessible to the calling code, either bound to the " |
| + ThreadContext.class.getName() + " or as a vm static singleton. This is an invalid application " |
| + "configuration."; |
| throw new UnavailableSecurityManagerException(msg); |
| } |
| return securityManager; |
| } |
| |
| /** |
| * Returns the SecurityManager, ensuring it is of the specified type. |
| * Unwraps wrapped SecurityManagers if necessary. |
| * Caution, since this method unwraps SecurityManagers, it is possible that |
| * functionality of the wrapper is lost by the returned instance. |
| * |
| * @param type the expected type of the SecurityManager |
| * @return the SecurityManager. |
| * @param <SM> the expected type of the SecurityManager |
| */ |
| public static <SM extends SecurityManager> SM getSecurityManager(Class<SM> type) { |
| Objects.requireNonNull(type, "Class argument cannot be null."); |
| return unwrapSecurityManager(getSecurityManager(), type); |
| } |
| |
| /** |
| * Determines if the specified security manager is of the specified type or a subclass of the specified type. |
| * |
| * @param securityManager |
| * @param type |
| * @return true if the security manager is of the specified type or a subclass of the specified type, false otherwise. |
| */ |
| public static boolean isSecurityManagerTypeOf(SecurityManager securityManager, |
| Class<? extends SecurityManager> type) { |
| return type.isAssignableFrom(unwrapSecurityManager(securityManager, type).getClass()); |
| } |
| |
| /** |
| * Unwraps wrapped SecurityManagers if necessary. |
| * @param securityManager the SecurityManager to unwrap |
| * @param type the expected type of the SecurityManager |
| * @return the unwrapped SecurityManager |
| * @param <SM> Type of the SecurityManager |
| */ |
| public static <SM extends SecurityManager> SM |
| unwrapSecurityManager(SecurityManager securityManager, Class<SM> type) { |
| return unwrapSecurityManager(securityManager, type, type::isAssignableFrom); |
| } |
| |
| /** |
| * Unwraps wrapped SecurityManagers if necessary. |
| * @param securityManager the SecurityManager to unwrap |
| * @param type the expected type of the SecurityManager |
| * @param predicate to determine if the SecurityManager is of the expected type |
| * @return the unwrapped SecurityManager |
| * @param <SM> Type of the SecurityManager |
| */ |
| @SuppressWarnings("unchecked") |
| public static <SM extends SecurityManager> SM |
| unwrapSecurityManager(SecurityManager securityManager, Class<SM> type, |
| Predicate<Class<? extends SecurityManager>> predicate) { |
| while (securityManager instanceof WrappedSecurityManager && !predicate.test(securityManager.getClass())) { |
| WrappedSecurityManager wrappedSecurityManager = (WrappedSecurityManager) securityManager; |
| securityManager = wrappedSecurityManager.unwrap(); |
| if (securityManager == wrappedSecurityManager) { |
| throw new IllegalStateException("SecurityManager implementation of type [" + type.getName() |
| + "] is wrapped by itself, which is an invalid configuration."); |
| } |
| } |
| return (SM) securityManager; |
| } |
| } |