1 /*
2 * Copyright (c) 2003, 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.transform;
27
28 import java.io.File;
29 import java.lang.reflect.Method;
30 import java.lang.reflect.Modifier;
31 import java.security.AccessController;
32 import java.security.PrivilegedAction;
33 import java.util.Iterator;
34 import java.util.Properties;
35 import java.util.ServiceConfigurationError;
36 import java.util.ServiceLoader;
37 import java.util.function.Supplier;
38 import jdk.xml.internal.SecuritySupport;
39
40 /**
41 * <p>Implements pluggable Datatypes.</p>
42 *
43 * <p>This class is duplicated for each JAXP subpackage so keep it in
44 * sync. It is package private for secure class loading.</p>
45 *
46 * @author Santiago PericasGeertsen
47 */
48 class FactoryFinder {
49 private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xalan.internal.";
50
51 /**
52 * Internal debug flag.
53 */
54 private static boolean debug = false;
55
56 /**
57 * Cache for properties in java.home/conf/jaxp.properties
58 */
59 private final static Properties cacheProps = new Properties();
60
61 /**
62 * Flag indicating if properties from java.home/conf/jaxp.properties
63 * have been cached.
64 */
65 static volatile boolean firstTime = true;
66
67 // Define system property "jaxp.debug" to get output
68 static {
69 // Use try/catch block to support applets, which throws
70 // SecurityException out of this code.
71 try {
72 String val = SecuritySupport.getSystemProperty("jaxp.debug");
73 // Allow simply setting the prop to turn on debug
74 debug = val != null && !"false".equals(val);
75 }
76 catch (SecurityException se) {
77 debug = false;
78 }
79 }
80
81 private static void dPrint(Supplier<String> msgGen) {
82 if (debug) {
83 System.err.println("JAXP: " + msgGen.get());
84 }
85 }
86
87 /**
88 * Attempt to load a class using the class loader supplied. If that fails
89 * and fall back is enabled, the current (i.e. bootstrap) class loader is
90 * tried.
91 *
92 * If the class loader supplied is <code>null</code>, first try using the
93 * context class loader followed by the current (i.e. bootstrap) class
94 * loader.
95 *
96 * Use bootstrap classLoader if cl = null and useBSClsLoader is true
97 */
98 static private Class<?> getProviderClass(String className, ClassLoader cl,
99 boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException
100 {
101 try {
102 if (cl == null) {
103 if (useBSClsLoader) {
104 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
105 } else {
106 cl = SecuritySupport.getContextClassLoader();
107 if (cl == null) {
108 throw new ClassNotFoundException();
109 }
110 else {
111 return Class.forName(className, false, cl);
112 }
113 }
114 }
115 else {
116 return Class.forName(className, false, cl);
117 }
118 }
119 catch (ClassNotFoundException e1) {
120 if (doFallback) {
121 // Use current class loader - should always be bootstrap CL
122 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
123 }
124 else {
125 throw e1;
126 }
127 }
128 }
129
130 /**
131 * Create an instance of a class. Delegates to method
132 * <code>getProviderClass()</code> in order to load the class.
133 *
134 * @param type Base class / Service interface of the factory to
135 * instantiate.
136 *
137 * @param className Name of the concrete class corresponding to the
138 * service provider
139 *
140 * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
141 * current <code>Thread</code>'s context classLoader is used to load the factory class.
142 *
143 * @param doFallback True if the current ClassLoader should be tried as
144 * a fallback if the class is not found using cl
145 *
146 * @param useServicesMechanism True use services mechanism
147 */
148 static <T> T newInstance(Class<T> type, String className, ClassLoader cl,
149 boolean doFallback, boolean useServicesMechanism)
150 throws TransformerFactoryConfigurationError
151 {
152 assert type != null;
153
154 boolean useBSClsLoader = false;
155 // make sure we have access to restricted packages
156 if (System.getSecurityManager() != null) {
157 if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
158 cl = null;
159 useBSClsLoader = true;
160 }
161 }
162
163 try {
164 Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
165 if (!type.isAssignableFrom(providerClass)) {
166 throw new ClassCastException(className + " cannot be cast to " + type.getName());
167 }
168 Object instance = null;
169 if (!useServicesMechanism) {
170 instance = newInstanceNoServiceLoader(type, providerClass);
171 }
172 if (instance == null) {
173 instance = providerClass.getConstructor().newInstance();
174 }
175 final ClassLoader clD = cl;
176 dPrint(()->"created new instance of " + providerClass +
177 " using ClassLoader: " + clD);
178 return type.cast(instance);
179 }
180 catch (ClassNotFoundException x) {
181 throw new TransformerFactoryConfigurationError(x,
182 "Provider " + className + " not found");
183 }
184 catch (Exception x) {
185 throw new TransformerFactoryConfigurationError(x,
186 "Provider " + className + " could not be instantiated: " + x);
187 }
188 }
189
190 /**
191 * Try to construct using newTransformerFactoryNoServiceLoader
192 * method if available.
193 */
194 private static <T> T newInstanceNoServiceLoader(Class<T> type, Class<?> providerClass) {
195 // Retain maximum compatibility if no security manager.
196 if (System.getSecurityManager() == null) {
197 return null;
198 }
199 try {
200 final Method creationMethod =
201 providerClass.getDeclaredMethod(
202 "newTransformerFactoryNoServiceLoader"
203 );
204 final int modifiers = creationMethod.getModifiers();
205
206 // Do not call the method if it's not public static.
207 if (!Modifier.isPublic(modifiers) || !Modifier.isStatic(modifiers)) {
208 return null;
209 }
210
211 // Only call the method if it's declared to return an instance of
212 // TransformerFactory
213 final Class<?> returnType = creationMethod.getReturnType();
214 if (type.isAssignableFrom(returnType)) {
215 final Object result = creationMethod.invoke(null, (Object[])null);
216 return type.cast(result);
217 } else {
218 // This should not happen, as
219 // TransformerFactoryImpl.newTransformerFactoryNoServiceLoader is
220 // declared to return TransformerFactory.
221 throw new ClassCastException(returnType + " cannot be cast to " + type);
222 }
223 } catch (ClassCastException e) {
224 throw new TransformerFactoryConfigurationError(e, e.getMessage());
225 } catch (NoSuchMethodException exc) {
226 return null;
227 } catch (Exception exc) {
228 return null;
229 }
230 }
231
232 /**
233 * Finds the implementation Class object in the specified order. Main
234 * entry point.
235 * @return Class object of factory, never null
236 *
237 * @param type Base class / Service interface of the
238 * factory to find.
239 *
240 * @param fallbackClassName Implementation class name, if nothing else
241 * is found. Use null to mean no fallback.
242 *
243 * Package private so this code can be shared.
244 */
245 static <T> T find(Class<T> type, String fallbackClassName)
246 throws TransformerFactoryConfigurationError
247 {
248 assert type != null;
249
250 final String factoryId = type.getName();
251
252 dPrint(()->"find factoryId =" + factoryId);
253 // Use the system property first
254 try {
255 String systemProp = SecuritySupport.getSystemProperty(factoryId);
256 if (systemProp != null) {
257 dPrint(()->"found system property, value=" + systemProp);
258 return newInstance(type, systemProp, null, true, true);
259 }
260 }
261 catch (SecurityException se) {
262 if (debug) se.printStackTrace();
263 }
264
265 // try to read from $java.home/conf/jaxp.properties
266 try {
267 if (firstTime) {
268 synchronized (cacheProps) {
269 if (firstTime) {
270 String configFile = SecuritySupport.getSystemProperty("java.home") + File.separator +
271 "conf" + File.separator + "jaxp.properties";
272 File f = new File(configFile);
273 firstTime = false;
274 if (SecuritySupport.doesFileExist(f)) {
275 dPrint(()->"Read properties file "+f);
276 cacheProps.load(SecuritySupport.getFileInputStream(f));
277 }
278 }
279 }
280 }
281 final String factoryClassName = cacheProps.getProperty(factoryId);
282
283 if (factoryClassName != null) {
284 dPrint(()->"found in ${java.home}/conf/jaxp.properties, value=" + factoryClassName);
285 return newInstance(type, factoryClassName, null, true, true);
286 }
287 }
288 catch (Exception ex) {
289 if (debug) ex.printStackTrace();
290 }
291
292 // Try Jar Service Provider Mechanism
293 T provider = findServiceProvider(type);
294 if (provider != null) {
295 return provider;
296 }
297 if (fallbackClassName == null) {
298 throw new TransformerFactoryConfigurationError(null,
299 "Provider for " + factoryId + " cannot be found");
300 }
301
302 dPrint(()->"loaded from fallback value: " + fallbackClassName);
303 return newInstance(type, fallbackClassName, null, true, true);
304 }
305
306 /*
307 * Try to find provider using the ServiceLoader.
308 *
309 * @param type Base class / Service interface of the factory to find.
310 *
311 * @return instance of provider class if found or null
312 */
313 private static <T> T findServiceProvider(final Class<T> type)
314 throws TransformerFactoryConfigurationError
315 {
316 try {
317 return AccessController.doPrivileged(new PrivilegedAction<T>() {
318 public T run() {
319 final ServiceLoader<T> serviceLoader = ServiceLoader.load(type);
320 final Iterator<T> iterator = serviceLoader.iterator();
321 if (iterator.hasNext()) {
322 return iterator.next();
323 } else {
324 return null;
325 }
326 }
327 });
328 } catch(ServiceConfigurationError e) {
329 // It is not possible to wrap an error directly in
330 // FactoryConfigurationError - so we need to wrap the
331 // ServiceConfigurationError in a RuntimeException.
332 // The alternative would be to modify the logic in
333 // FactoryConfigurationError to allow setting a
334 // Throwable as the cause, but that could cause
335 // compatibility issues down the road.
336 final RuntimeException x = new RuntimeException(
337 "Provider for " + type + " cannot be created", e);
338 final TransformerFactoryConfigurationError error =
339 new TransformerFactoryConfigurationError(x, x.getMessage());
340 throw error;
341 }
342 }
343 }