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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache license, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License. You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the license for the specific language governing permissions and
15   * limitations under the license.
16   */
17  package org.apache.logging.log4j.web;
18  
19  import java.net.URI;
20  import java.net.URL;
21  import java.util.Map;
22  import java.util.concurrent.ConcurrentHashMap;
23  import javax.servlet.ServletContext;
24  
25  import org.apache.logging.log4j.LogManager;
26  import org.apache.logging.log4j.Logger;
27  import org.apache.logging.log4j.core.AbstractLifeCycle;
28  import org.apache.logging.log4j.core.LoggerContext;
29  import org.apache.logging.log4j.core.config.Configurator;
30  import org.apache.logging.log4j.core.impl.ContextAnchor;
31  import org.apache.logging.log4j.core.impl.Log4jContextFactory;
32  import org.apache.logging.log4j.core.lookup.Interpolator;
33  import org.apache.logging.log4j.core.lookup.StrSubstitutor;
34  import org.apache.logging.log4j.core.selector.ContextSelector;
35  import org.apache.logging.log4j.core.selector.NamedContextSelector;
36  import org.apache.logging.log4j.core.util.FileUtils;
37  import org.apache.logging.log4j.core.util.Loader;
38  import org.apache.logging.log4j.core.util.NetUtils;
39  import org.apache.logging.log4j.core.util.SetUtils;
40  import org.apache.logging.log4j.spi.LoggerContextFactory;
41  import org.apache.logging.log4j.status.StatusLogger;
42  
43  /**
44   * This class initializes and deinitializes Log4j no matter how the initialization occurs.
45   */
46  final class Log4jWebInitializerImpl extends AbstractLifeCycle implements Log4jWebLifeCycle {
47  
48      private static final Logger LOGGER = StatusLogger.getLogger();
49  
50      private static final long serialVersionUID = 1L;
51  
52      static {
53          if (Loader.isClassAvailable("org.apache.logging.log4j.core.web.JNDIContextFilter")) {
54              throw new IllegalStateException("You are using Log4j 2 in a web application with the old, extinct " +
55                      "log4j-web artifact. This is not supported and could cause serious runtime problems. Please" +
56                      "remove the log4j-web JAR file from your application.");
57          }
58      }
59  
60      private final Map<String, String> map = new ConcurrentHashMap<String, String>();
61      private final StrSubstitutor substitutor = new StrSubstitutor(new Interpolator(map));
62      private final ServletContext servletContext;
63  
64      private String name;
65      private NamedContextSelector namedContextSelector;
66      private LoggerContext loggerContext;
67  
68      private Log4jWebInitializerImpl(final ServletContext servletContext) {
69          this.servletContext = servletContext;
70          this.map.put("hostName", NetUtils.getLocalHostname());
71      }
72  
73      /**
74       * Initializes the Log4jWebLifeCycle attribute of a ServletContext. Those who wish to obtain this object should
75       * use the {@link org.apache.logging.log4j.web.WebLoggerContextUtils#getWebLifeCycle(javax.servlet.ServletContext)}
76       * method instead.
77       *
78       * @param servletContext the ServletContext to initialize
79       * @return a new Log4jWebLifeCycle
80       * @since 2.0.1
81       */
82      protected static Log4jWebInitializerImpl initialize(final ServletContext servletContext) {
83          final Log4jWebInitializerImpl initializer = new Log4jWebInitializerImpl(servletContext);
84          servletContext.setAttribute(SUPPORT_ATTRIBUTE, initializer);
85          return initializer;
86      }
87  
88      @Override
89      public synchronized void start() {
90          if (this.isStopped() || this.isStopping()) {
91              throw new IllegalStateException("Cannot start this Log4jWebInitializerImpl after it was stopped.");
92          }
93  
94          // only do this once
95          if (this.isInitialized()) {
96              super.setStarting();
97  
98              this.name = this.substitutor.replace(this.servletContext.getInitParameter(LOG4J_CONTEXT_NAME));
99              final String location =
100                     this.substitutor.replace(this.servletContext.getInitParameter(LOG4J_CONFIG_LOCATION));
101             final boolean isJndi =
102                     "true".equalsIgnoreCase(this.servletContext.getInitParameter(IS_LOG4J_CONTEXT_SELECTOR_NAMED));
103 
104             if (isJndi) {
105                 this.initializeJndi(location);
106             } else {
107                 this.initializeNonJndi(location);
108             }
109 
110             this.servletContext.setAttribute(CONTEXT_ATTRIBUTE, this.loggerContext);
111             super.setStarted();
112         }
113     }
114 
115     private void initializeJndi(final String location) {
116         final URI configLocation = getConfigURI(location);
117 
118         if (this.name == null) {
119             throw new IllegalStateException("A log4jContextName context parameter is required");
120         }
121 
122         LoggerContext context;
123         final LoggerContextFactory factory = LogManager.getFactory();
124         if (factory instanceof Log4jContextFactory) {
125             final ContextSelector selector = ((Log4jContextFactory) factory).getSelector();
126             if (selector instanceof NamedContextSelector) {
127                 this.namedContextSelector = (NamedContextSelector) selector;
128                 context = this.namedContextSelector.locateContext(this.name, this.servletContext, configLocation);
129                 ContextAnchor.THREAD_CONTEXT.set(context);
130                 if (context.isInitialized()) {
131                     context.start();
132                 }
133                 ContextAnchor.THREAD_CONTEXT.remove();
134             } else {
135                 LOGGER.warn("Potential problem: Selector is not an instance of NamedContextSelector.");
136                 return;
137             }
138         } else {
139             LOGGER.warn("Potential problem: LoggerContextFactory is not an instance of Log4jContextFactory.");
140             return;
141         }
142         this.loggerContext = context;
143         LOGGER.debug("Created logger context for [{}] using [{}].", this.name, context.getClass().getClassLoader());
144     }
145 
146     private void initializeNonJndi(final String location) {
147         if (this.name == null) {
148             this.name = this.servletContext.getServletContextName();
149         }
150 
151         if (this.name == null && location == null) {
152             LOGGER.error("No Log4j context configuration provided. This is very unusual.");
153             return;
154         }
155 
156         final URI uri = getConfigURI(location);
157         this.loggerContext = Configurator.initialize(this.name, this.getClassLoader(), uri, this.servletContext);
158     }
159 
160     private URI getConfigURI(final String location) {
161         try {
162             String configLocation = location;
163             if (configLocation == null) {
164                 final String[] paths = SetUtils.prefixSet(servletContext.getResourcePaths("/WEB-INF/"), "/WEB-INF/log4j2");
165                 if (paths.length == 1) {
166                     configLocation = paths[0];
167                 } else if (paths.length > 1) {
168                     final String prefix = "/WEB-INF/log4j2-" + this.name + ".";
169                     boolean found = false;
170                     for (final String str : paths) {
171                         if (str.startsWith(prefix)) {
172                             configLocation = str;
173                             found = true;
174                             break;
175                         }
176                     }
177                     if (!found) {
178                         configLocation = paths[0];
179                     }
180                 }
181             }
182             if (configLocation != null) {
183                 final URL url = servletContext.getResource(configLocation);
184                 if (url != null) {
185                     return url.toURI();
186                 }
187             }
188         } catch (final Exception ex) {
189             // Just try passing the location.
190         }
191         if (location != null) {
192             try {
193                 return FileUtils.getCorrectedFilePathUri(location);
194             } catch (final Exception e) {
195                 LOGGER.error("Unable to convert configuration location [{}] to a URI", location, e);
196             }
197         }
198         return null;
199     }
200 
201     @Override
202     public synchronized void stop() {
203         if (!this.isStarted() && !this.isStopped()) {
204             throw new IllegalStateException("Cannot stop this Log4jWebInitializer because it has not started.");
205         }
206 
207         // only do this once
208         if (this.isStarted()) {
209             this.setStopping();
210             if (this.loggerContext != null) {
211                 LOGGER.debug("Removing LoggerContext for [{}].", this.name);
212                 this.servletContext.removeAttribute(CONTEXT_ATTRIBUTE);
213                 if (this.namedContextSelector != null) {
214                     this.namedContextSelector.removeContext(this.name);
215                 }
216                 this.loggerContext.stop();
217                 this.loggerContext.setExternalContext(null);
218                 this.loggerContext = null;
219             }
220             this.setStopped();
221         }
222     }
223 
224     @Override
225     public void setLoggerContext() {
226         if (this.loggerContext != null) {
227             ContextAnchor.THREAD_CONTEXT.set(this.loggerContext);
228         }
229     }
230 
231     @Override
232     public void clearLoggerContext() {
233         ContextAnchor.THREAD_CONTEXT.remove();
234     }
235 
236     @Override
237     public void wrapExecution(final Runnable runnable) {
238         this.setLoggerContext();
239 
240         try {
241             runnable.run();
242         } finally {
243             this.clearLoggerContext();
244         }
245     }
246 
247     private ClassLoader getClassLoader() {
248         try {
249             // if container is Servlet 3.0, use its getClassLoader method
250             // this may look odd, but the call below will throw NoSuchMethodError if user is on Servlet 2.5
251             // we compile against 3.0 to support Log4jServletContainerInitializer, but we don't require 3.0
252             return this.servletContext.getClassLoader();
253         } catch (final Throwable ignore) {
254             // otherwise, use this class's class loader
255             return Log4jWebInitializerImpl.class.getClassLoader();
256         }
257     }
258 
259 }