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Elasticsearch - Open Source, Distributed, RESTful Search Engine
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.bootstrap;
import org.elasticsearch.Version;
import org.elasticsearch.common.SuppressForbidden;
import org.elasticsearch.common.io.PathUtils;
import org.elasticsearch.common.logging.ESLogger;
import org.elasticsearch.common.logging.Loggers;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
/**
* Simple check for duplicate class files across the classpath.
*
* This class checks for incompatibilities in the following ways:
*
* - Checks that class files are not duplicated across jars.
* - Checks any {@code X-Compile-Target-JDK} value in the jar
* manifest is compatible with current JRE
* - Checks any {@code X-Compile-Elasticsearch-Version} value in
* the jar manifest is compatible with the current ES
*
*/
public class JarHell {
/** no instantiation */
private JarHell() {}
/** Simple driver class, can be used eg. from builds. Returns non-zero on jar-hell */
@SuppressForbidden(reason = "command line tool")
public static void main(String args[]) throws Exception {
System.out.println("checking for jar hell...");
checkJarHell();
System.out.println("no jar hell found");
}
/**
* Checks the current classpath for duplicate classes
* @throws IllegalStateException if jar hell was found
*/
public static void checkJarHell() throws Exception {
ClassLoader loader = JarHell.class.getClassLoader();
ESLogger logger = Loggers.getLogger(JarHell.class);
if (logger.isDebugEnabled()) {
logger.debug("java.class.path: {}", System.getProperty("java.class.path"));
logger.debug("sun.boot.class.path: {}", System.getProperty("sun.boot.class.path"));
if (loader instanceof URLClassLoader ) {
logger.debug("classloader urls: {}", Arrays.toString(((URLClassLoader)loader).getURLs()));
}
}
checkJarHell(parseClassPath());
}
/**
* Parses the classpath into an array of URLs
* @return array of URLs
* @throws IllegalStateException if the classpath contains empty elements
*/
public static URL[] parseClassPath() {
return parseClassPath(System.getProperty("java.class.path"));
}
/**
* Parses the classpath into a set of URLs. For testing.
* @param classPath classpath to parse (typically the system property {@code java.class.path})
* @return array of URLs
* @throws IllegalStateException if the classpath contains empty elements
*/
@SuppressForbidden(reason = "resolves against CWD because that is how classpaths work")
static URL[] parseClassPath(String classPath) {
String pathSeparator = System.getProperty("path.separator");
String fileSeparator = System.getProperty("file.separator");
String elements[] = classPath.split(pathSeparator);
URL urlElements[] = new URL[elements.length];
for (int i = 0; i < elements.length; i++) {
String element = elements[i];
// Technically empty classpath element behaves like CWD.
// So below is the "correct" code, however in practice with ES, this is usually just a misconfiguration,
// from old shell scripts left behind or something:
// if (element.isEmpty()) {
// element = System.getProperty("user.dir");
// }
// Instead we just throw an exception, and keep it clean.
if (element.isEmpty()) {
throw new IllegalStateException("Classpath should not contain empty elements! (outdated shell script from a previous version?) classpath='" + classPath + "'");
}
// we should be able to just Paths.get() each element, but unfortunately this is not the
// whole story on how classpath parsing works: if you want to know, start at sun.misc.Launcher,
// be sure to stop before you tear out your eyes. we just handle the "alternative" filename
// specification which java seems to allow, explicitly, right here...
if (element.startsWith("/") && "\\".equals(fileSeparator)) {
// "correct" the entry to become a normal entry
// change to correct file separators
element = element.replace("/", "\\");
// if there is a drive letter, nuke the leading separator
if (element.length() >= 3 && element.charAt(2) == ':') {
element = element.substring(1);
}
}
// now just parse as ordinary file
try {
urlElements[i] = PathUtils.get(element).toUri().toURL();
} catch (MalformedURLException e) {
// should not happen, as we use the filesystem API
throw new RuntimeException(e);
}
}
return urlElements;
}
/**
* Checks the set of URLs for duplicate classes
* @throws IllegalStateException if jar hell was found
*/
@SuppressForbidden(reason = "needs JarFile for speed, just reading entries")
public static void checkJarHell(URL urls[]) throws Exception {
ESLogger logger = Loggers.getLogger(JarHell.class);
// we don't try to be sneaky and use deprecated/internal/not portable stuff
// like sun.boot.class.path, and with jigsaw we don't yet have a way to get
// a "list" at all. So just exclude any elements underneath the java home
String javaHome = System.getProperty("java.home");
logger.debug("java.home: {}", javaHome);
final Map clazzes = new HashMap<>(32768);
Set seenJars = new HashSet<>();
for (final URL url : urls) {
final Path path = PathUtils.get(url.toURI());
// exclude system resources
if (path.startsWith(javaHome)) {
logger.debug("excluding system resource: {}", path);
continue;
}
if (path.toString().endsWith(".jar")) {
if (!seenJars.add(path)) {
logger.debug("excluding duplicate classpath element: {}", path);
continue; // we can't fail because of sheistiness with joda-time
}
logger.debug("examining jar: {}", path);
try (JarFile file = new JarFile(path.toString())) {
Manifest manifest = file.getManifest();
if (manifest != null) {
checkManifest(manifest, path);
}
// inspect entries
Enumeration elements = file.entries();
while (elements.hasMoreElements()) {
String entry = elements.nextElement().getName();
if (entry.endsWith(".class")) {
// for jar format, the separator is defined as /
entry = entry.replace('/', '.').substring(0, entry.length() - 6);
checkClass(clazzes, entry, path);
}
}
}
} else {
logger.debug("examining directory: {}", path);
// case for tests: where we have class files in the classpath
final Path root = PathUtils.get(url.toURI());
final String sep = root.getFileSystem().getSeparator();
Files.walkFileTree(root, new SimpleFileVisitor() {
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
String entry = root.relativize(file).toString();
if (entry.endsWith(".class")) {
// normalize with the os separator
entry = entry.replace(sep, ".").substring(0, entry.length() - 6);
checkClass(clazzes, entry, path);
}
return super.visitFile(file, attrs);
}
});
}
}
}
/** inspect manifest for sure incompatibilities */
static void checkManifest(Manifest manifest, Path jar) {
// give a nice error if jar requires a newer java version
String targetVersion = manifest.getMainAttributes().getValue("X-Compile-Target-JDK");
if (targetVersion != null) {
checkVersionFormat(targetVersion);
checkJavaVersion(jar.toString(), targetVersion);
}
// give a nice error if jar is compiled against different es version
String systemESVersion = Version.CURRENT.toString();
String targetESVersion = manifest.getMainAttributes().getValue("X-Compile-Elasticsearch-Version");
if (targetESVersion != null && targetESVersion.equals(systemESVersion) == false) {
throw new IllegalStateException(jar + " requires Elasticsearch " + targetESVersion
+ ", your system: " + systemESVersion);
}
}
public static void checkVersionFormat(String targetVersion) {
if (!JavaVersion.isValid(targetVersion)) {
throw new IllegalStateException(
String.format(
Locale.ROOT,
"version string must be a sequence of nonnegative decimal integers separated by \".\"'s and may have leading zeros but was %s",
targetVersion
)
);
}
}
/**
* Checks that the java specification version {@code targetVersion}
* required by {@code resource} is compatible with the current installation.
*/
public static void checkJavaVersion(String resource, String targetVersion) {
JavaVersion version = JavaVersion.parse(targetVersion);
if (JavaVersion.current().compareTo(version) < 0) {
throw new IllegalStateException(
String.format(
Locale.ROOT,
"%s requires Java %s:, your system: %s",
resource,
targetVersion,
JavaVersion.current().toString()
)
);
}
}
static void checkClass(Map clazzes, String clazz, Path jarpath) {
Path previous = clazzes.put(clazz, jarpath);
if (previous != null) {
if (previous.equals(jarpath)) {
if (clazz.startsWith("org.apache.xmlbeans")) {
return; // https://issues.apache.org/jira/browse/XMLBEANS-499
}
// throw a better exception in this ridiculous case.
// unfortunately the zip file format allows this buggy possibility
// UweSays: It can, but should be considered as bug :-)
throw new IllegalStateException("jar hell!" + System.lineSeparator() +
"class: " + clazz + System.lineSeparator() +
"exists multiple times in jar: " + jarpath + " !!!!!!!!!");
} else {
if (clazz.startsWith("org.apache.log4j")) {
return; // go figure, jar hell for what should be System.out.println...
}
if (clazz.equals("org.joda.time.base.BaseDateTime")) {
return; // apparently this is intentional... clean this up
}
throw new IllegalStateException("jar hell!" + System.lineSeparator() +
"class: " + clazz + System.lineSeparator() +
"jar1: " + previous + System.lineSeparator() +
"jar2: " + jarpath);
}
}
}
}