1 /*
2 * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.xml.stream;
27
28 import java.io.File;
29 import java.security.AccessController;
30 import java.security.PrivilegedAction;
31 import java.util.Iterator;
32 import java.util.Properties;
33 import java.util.ServiceConfigurationError;
34 import java.util.ServiceLoader;
35 import java.util.function.Supplier;
36 import jdk.xml.internal.SecuritySupport;
37
38 /**
39 * <p>Implements pluggable streams.</p>
40 *
41 * <p>This class is duplicated for each JAXP subpackage so keep it in
42 * sync. It is package private for secure class loading.</p>
43 *
44 * @author Santiago PericasGeertsen
45 */
46 class FactoryFinder {
47 // Check we have access to package.
48 private static final String DEFAULT_PACKAGE = "com.sun.xml.internal.";
49
50 /**
51 * Internal debug flag.
52 */
53 private static boolean debug = false;
54
55 /**
56 * Cache for properties in java.home/conf/jaxp.properties
57 */
58 final private static Properties cacheProps = new Properties();
59
60 /**
61 * Flag indicating if properties from java.home/conf/jaxp.properties
62 * have been cached.
63 */
64 private static volatile boolean firstTime = true;
65
66 // Define system property "jaxp.debug" to get output
67 static {
68 // Use try/catch block to support applets, which throws
69 // SecurityException out of this code.
70 try {
71 String val = SecuritySupport.getSystemProperty("jaxp.debug");
72 // Allow simply setting the prop to turn on debug
73 debug = val != null && !"false".equals(val);
74 }
75 catch (SecurityException se) {
76 debug = false;
77 }
78 }
79
80 private static void dPrint(Supplier<String> msgGen) {
81 if (debug) {
82 System.err.println("JAXP: " + msgGen.get());
83 }
84 }
85
86 /**
87 * Attempt to load a class using the class loader supplied. If that fails
88 * and fall back is enabled, the current (i.e. bootstrap) class loader is
89 * tried.
90 *
91 * If the class loader supplied is <code>null</code>, first try using the
92 * context class loader followed by the current (i.e. bootstrap) class
93 * loader.
94 *
95 * Use bootstrap classLoader if cl = null and useBSClsLoader is true
96 */
97 static private Class<?> getProviderClass(String className, ClassLoader cl,
98 boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException
99 {
100 try {
101 if (cl == null) {
102 if (useBSClsLoader) {
103 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
104 } else {
105 cl = SecuritySupport.getContextClassLoader();
106 if (cl == null) {
107 throw new ClassNotFoundException();
108 }
109 else {
110 return Class.forName(className, false, cl);
111 }
112 }
113 }
114 else {
115 return Class.forName(className, false, cl);
116 }
117 }
118 catch (ClassNotFoundException e1) {
119 if (doFallback) {
120 // Use current class loader - should always be bootstrap CL
121 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
122 }
123 else {
124 throw e1;
125 }
126 }
127 }
128
129 /**
130 * Create an instance of a class. Delegates to method
131 * <code>getProviderClass()</code> in order to load the class.
132 *
133 * @param type Base class / Service interface of the factory to
134 * instantiate.
135 *
136 * @param className Name of the concrete class corresponding to the
137 * service provider
138 *
139 * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
140 * current <code>Thread</code>'s context classLoader is used to load the factory class.
141 *
142 * @param doFallback True if the current ClassLoader should be tried as
143 * a fallback if the class is not found using cl
144 */
145 static <T> T newInstance(Class<T> type, String className, ClassLoader cl, boolean doFallback)
146 throws FactoryConfigurationError
147 {
148 return newInstance(type, className, cl, doFallback, false);
149 }
150
151 /**
152 * Create an instance of a class. Delegates to method
153 * <code>getProviderClass()</code> in order to load the class.
154 *
155 * @param type Base class / Service interface of the factory to
156 * instantiate.
157 *
158 * @param className Name of the concrete class corresponding to the
159 * service provider
160 *
161 * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
162 * current <code>Thread</code>'s context classLoader is used to load the factory class.
163 *
164 * @param doFallback True if the current ClassLoader should be tried as
165 * a fallback if the class is not found using cl
166 *
167 * @param useBSClsLoader True if cl=null actually meant bootstrap classLoader. This parameter
168 * is needed since DocumentBuilderFactory/SAXParserFactory defined null as context classLoader.
169 */
170 static <T> T newInstance(Class<T> type, String className, ClassLoader cl,
171 boolean doFallback, boolean useBSClsLoader)
172 throws FactoryConfigurationError
173 {
174 assert type != null;
175
176 // make sure we have access to restricted packages
177 if (System.getSecurityManager() != null) {
178 if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
179 cl = null;
180 useBSClsLoader = true;
181 }
182 }
183
184 try {
185 Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
186 if (!type.isAssignableFrom(providerClass)) {
187 throw new ClassCastException(className + " cannot be cast to " + type.getName());
188 }
189 Object instance = providerClass.getConstructor().newInstance();
190 final ClassLoader clD = cl;
191 dPrint(()->"created new instance of " + providerClass +
192 " using ClassLoader: " + clD);
193 return type.cast(instance);
194 }
195 catch (ClassNotFoundException x) {
196 throw new FactoryConfigurationError(
197 "Provider " + className + " not found", x);
198 }
199 catch (Exception x) {
200 throw new FactoryConfigurationError(
201 "Provider " + className + " could not be instantiated: " + x,
202 x);
203 }
204 }
205
206 /**
207 * Finds the implementation Class object in the specified order.
208 *
209 * @return Class object of factory, never null
210 *
211 * @param type Base class / Service interface of the
212 * factory to find.
213 *
214 * @param fallbackClassName Implementation class name, if nothing else
215 * is found. Use null to mean no fallback.
216 *
217 * Package private so this code can be shared.
218 */
219 static <T> T find(Class<T> type, String fallbackClassName)
220 throws FactoryConfigurationError
221 {
222 return find(type, type.getName(), null, fallbackClassName);
223 }
224
225 /**
226 * Finds the implementation Class object in the specified order. Main
227 * entry point.
228 * @return Class object of factory, never null
229 *
230 * @param type Base class / Service interface of the
231 * factory to find.
232 *
233 * @param factoryId Name of the factory to find, same as
234 * a property name
235 *
236 * @param cl ClassLoader to be used to load the class, null means to use
237 * the bootstrap ClassLoader
238 *
239 * @param fallbackClassName Implementation class name, if nothing else
240 * is found. Use null to mean no fallback.
241 *
242 * Package private so this code can be shared.
243 */
244 static <T> T find(Class<T> type, String factoryId, ClassLoader cl, String fallbackClassName)
245 throws FactoryConfigurationError
246 {
247 dPrint(()->"find factoryId =" + factoryId);
248
249 // Use the system property first
250 try {
251
252 final String systemProp;
253 if (type.getName().equals(factoryId)) {
254 systemProp = SecuritySupport.getSystemProperty(factoryId);
255 } else {
256 systemProp = System.getProperty(factoryId);
257 }
258 if (systemProp != null) {
259 dPrint(()->"found system property, value=" + systemProp);
260 return newInstance(type, systemProp, cl, true);
261 }
262 }
263 catch (SecurityException se) {
264 throw new FactoryConfigurationError(
265 "Failed to read factoryId '" + factoryId + "'", se);
266 }
267
268 // Try read $java.home/conf/stax.properties followed by
269 // $java.home/conf/jaxp.properties if former not present
270 String configFile = null;
271 try {
272 if (firstTime) {
273 synchronized (cacheProps) {
274 if (firstTime) {
275 configFile = SecuritySupport.getSystemProperty("java.home") + File.separator +
276 "conf" + File.separator + "stax.properties";
277 final File fStax = new File(configFile);
278 firstTime = false;
279 if (SecuritySupport.doesFileExist(fStax)) {
280 dPrint(()->"Read properties file "+fStax);
281 cacheProps.load(SecuritySupport.getFileInputStream(fStax));
282 }
283 else {
284 configFile = SecuritySupport.getSystemProperty("java.home") + File.separator +
285 "conf" + File.separator + "jaxp.properties";
286 final File fJaxp = new File(configFile);
287 if (SecuritySupport.doesFileExist(fJaxp)) {
288 dPrint(()->"Read properties file "+fJaxp);
289 cacheProps.load(SecuritySupport.getFileInputStream(fJaxp));
290 }
291 }
292 }
293 }
294 }
295 final String factoryClassName = cacheProps.getProperty(factoryId);
296
297 if (factoryClassName != null) {
298 final String foundIn = configFile;
299 dPrint(()->"found in " + foundIn + " value=" + factoryClassName);
300 return newInstance(type, factoryClassName, cl, true);
301 }
302 }
303 catch (Exception ex) {
304 if (debug) ex.printStackTrace();
305 }
306
307 if (type.getName().equals(factoryId)) {
308 // Try Jar Service Provider Mechanism
309 final T provider = findServiceProvider(type, cl);
310 if (provider != null) {
311 return provider;
312 }
313 } else {
314 // We're in the case where a 'custom' factoryId was provided,
315 // and in every case where that happens, we expect that
316 // fallbackClassName will be null.
317 assert fallbackClassName == null;
318 }
319 if (fallbackClassName == null) {
320 throw new FactoryConfigurationError(
321 "Provider for " + factoryId + " cannot be found", null);
322 }
323
324 dPrint(()->"loaded from fallback value: " + fallbackClassName);
325 return newInstance(type, fallbackClassName, cl, true);
326 }
327
328 /*
329 * Try to find provider using the ServiceLoader API
330 *
331 * @param type Base class / Service interface of the factory to find.
332 *
333 * @return instance of provider class if found or null
334 */
335 private static <T> T findServiceProvider(final Class<T> type, final ClassLoader cl) {
336 try {
337 return AccessController.doPrivileged(new PrivilegedAction<T>() {
338 @Override
339 public T run() {
340 final ServiceLoader<T> serviceLoader;
341 if (cl == null) {
342 //the current thread's context class loader
343 serviceLoader = ServiceLoader.load(type);
344 } else {
345 serviceLoader = ServiceLoader.load(type, cl);
346 }
347 final Iterator<T> iterator = serviceLoader.iterator();
348 if (iterator.hasNext()) {
349 return iterator.next();
350 } else {
351 return null;
352 }
353 }
354 });
355 } catch(ServiceConfigurationError e) {
356 // It is not possible to wrap an error directly in
357 // FactoryConfigurationError - so we need to wrap the
358 // ServiceConfigurationError in a RuntimeException.
359 // The alternative would be to modify the logic in
360 // FactoryConfigurationError to allow setting a
361 // Throwable as the cause, but that could cause
362 // compatibility issues down the road.
363 final RuntimeException x = new RuntimeException(
364 "Provider for " + type + " cannot be created", e);
365 final FactoryConfigurationError error =
366 new FactoryConfigurationError(x, x.getMessage());
367 throw error;
368 }
369 }
370
371 }