/*
* Copyright (c) 1999, 2014, 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.naming.internal;
import javax.naming.NamingEnumeration;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.*;
/**
* VersionHelper was used by JNDI to accommodate differences between
* JDK 1.1.x and the Java 2 platform. As this is no longer necessary
* since JNDI's inclusion in the platform, this class currently
* serves as a set of utilities for performing system-level things,
* such as class-loading and reading system properties.
*
* @author Rosanna Lee
* @author Scott Seligman
*/
public final class VersionHelper {
private static final VersionHelper helper = new VersionHelper();
final static String[] PROPS = new String[]{
javax.naming.Context.INITIAL_CONTEXT_FACTORY,
javax.naming.Context.OBJECT_FACTORIES,
javax.naming.Context.URL_PKG_PREFIXES,
javax.naming.Context.STATE_FACTORIES,
javax.naming.Context.PROVIDER_URL,
javax.naming.Context.DNS_URL,
// The following shouldn't create a runtime dependence on ldap package.
javax.naming.ldap.LdapContext.CONTROL_FACTORIES
};
public final static int INITIAL_CONTEXT_FACTORY = 0;
public final static int OBJECT_FACTORIES = 1;
public final static int URL_PKG_PREFIXES = 2;
public final static int STATE_FACTORIES = 3;
public final static int PROVIDER_URL = 4;
public final static int DNS_URL = 5;
public final static int CONTROL_FACTORIES = 6;
private VersionHelper() {} // Disallow anyone from creating one of these.
public static VersionHelper getVersionHelper() {
return helper;
}
public Class<?> loadClass(String className) throws ClassNotFoundException {
return loadClass(className, getContextClassLoader());
}
/**
* @param className A non-null fully qualified class name.
* @param codebase A non-null, space-separated list of URL strings.
*/
public Class<?> loadClass(String className, String codebase)
throws ClassNotFoundException, MalformedURLException {
ClassLoader parent = getContextClassLoader();
ClassLoader cl =
URLClassLoader.newInstance(getUrlArray(codebase), parent);
return loadClass(className, cl);
}
/**
* Package private.
* <p>
* This internal method is used with Thread Context Class Loader (TCCL),
* please don't expose this method as public.
*/
Class<?> loadClass(String className, ClassLoader cl)
throws ClassNotFoundException {
Class<?> cls = Class.forName(className, true, cl);
return cls;
}
/*
* Returns a JNDI property from the system properties. Returns
* null if the property is not set, or if there is no permission
* to read it.
*/
String getJndiProperty(int i) {
PrivilegedAction<String> act = () -> {
try {
return System.getProperty(PROPS[i]);
} catch (SecurityException e) {
return null;
}
};
return AccessController.doPrivileged(act);
}
/*
* Reads each property in PROPS from the system properties, and
* returns their values -- in order -- in an array. For each
* unset property, the corresponding array element is set to null.
* Returns null if there is no permission to call System.getProperties().
*/
String[] getJndiProperties() {
PrivilegedAction<Properties> act = () -> {
try {
return System.getProperties();
} catch (SecurityException e) {
return null;
}
};
Properties sysProps = AccessController.doPrivileged(act);
if (sysProps == null) {
return null;
}
String[] jProps = new String[PROPS.length];
for (int i = 0; i < PROPS.length; i++) {
jProps[i] = sysProps.getProperty(PROPS[i]);
}
return jProps;
}
private static String resolveName(Class<?> c, String name) {
if (name == null) {
return name;
}
if (!name.startsWith("/")) {
while (c.isArray()) {
c = c.getComponentType();
}
String baseName = c.getName();
int index = baseName.lastIndexOf('.');
if (index != -1) {
name = baseName.substring(0, index).replace('.', '/')
+"/"+name;
}
} else {
name = name.substring(1);
}
return name;
}
/*
* Returns the resource of a given name associated with a particular
* class (never null), or null if none can be found.
*/
InputStream getResourceAsStream(Class<?> c, String name) {
PrivilegedAction<InputStream> act = () -> {
try {
java.lang.reflect.Module m = c.getModule();
return c.getModule().getResourceAsStream(resolveName(c,name));
} catch (IOException x) {
return null;
}
};
return AccessController.doPrivileged(act);
}
/*
* Returns an input stream for a file in <java.home>/conf,
* or null if it cannot be located or opened.
*
* @param filename The file name, sans directory.
*/
InputStream getJavaHomeConfStream(String filename) {
PrivilegedAction<InputStream> act = () -> {
try {
String javahome = System.getProperty("java.home");
if (javahome == null) {
return null;
}
String pathname = javahome + File.separator +
"conf" + File.separator + filename;
return new FileInputStream(pathname);
} catch (Exception e) {
return null;
}
};
return AccessController.doPrivileged(act);
}
/*
* Returns an enumeration (never null) of InputStreams of the
* resources of a given name associated with a particular class
* loader. Null represents the bootstrap class loader in some
* Java implementations.
*/
NamingEnumeration<InputStream> getResources(ClassLoader cl,
String name) throws IOException {
Enumeration<URL> urls;
PrivilegedExceptionAction<Enumeration<URL>> act = () ->
(cl == null)
? ClassLoader.getSystemResources(name)
: cl.getResources(name);
try {
urls = AccessController.doPrivileged(act);
} catch (PrivilegedActionException e) {
throw (IOException) e.getException();
}
return new InputStreamEnumeration(urls);
}
/**
* Package private.
* <p>
* This internal method returns Thread Context Class Loader (TCCL),
* if null, returns the system Class Loader.
* <p>
* Please don't expose this method as public.
* @throws SecurityException if the class loader is not accessible
*/
ClassLoader getContextClassLoader() {
PrivilegedAction<ClassLoader> act = () -> {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
if (loader == null) {
// Don't use bootstrap class loader directly!
loader = ClassLoader.getSystemClassLoader();
}
return loader;
};
return AccessController.doPrivileged(act);
}
private static URL[] getUrlArray(String codebase)
throws MalformedURLException {
// Parse codebase into separate URLs
StringTokenizer parser = new StringTokenizer(codebase);
List<String> list = new ArrayList<>();
while (parser.hasMoreTokens()) {
list.add(parser.nextToken());
}
String[] url = new String[list.size()];
for (int i = 0; i < url.length; i++) {
url[i] = list.get(i);
}
URL[] urlArray = new URL[url.length];
for (int i = 0; i < urlArray.length; i++) {
urlArray[i] = new URL(url[i]);
}
return urlArray;
}
/**
* Given an enumeration of URLs, an instance of this class represents
* an enumeration of their InputStreams. Each operation on the URL
* enumeration is performed within a doPrivileged block.
* This is used to enumerate the resources under a foreign codebase.
* This class is not MT-safe.
*/
private class InputStreamEnumeration implements
NamingEnumeration<InputStream> {
private final Enumeration<URL> urls;
private InputStream nextElement;
InputStreamEnumeration(Enumeration<URL> urls) {
this.urls = urls;
}
/*
* Returns the next InputStream, or null if there are no more.
* An InputStream that cannot be opened is skipped.
*/
private InputStream getNextElement() {
PrivilegedAction<InputStream> act = () -> {
while (urls.hasMoreElements()) {
try {
return urls.nextElement().openStream();
} catch (IOException e) {
// skip this URL
}
}
return null;
};
return AccessController.doPrivileged(act);
}
public boolean hasMore() {
if (nextElement != null) {
return true;
}
nextElement = getNextElement();
return (nextElement != null);
}
public boolean hasMoreElements() {
return hasMore();
}
public InputStream next() {
if (hasMore()) {
InputStream res = nextElement;
nextElement = null;
return res;
} else {
throw new NoSuchElementException();
}
}
public InputStream nextElement() {
return next();
}
public void close() {
}
}
}