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/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF 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.apache.tomcat.util.scan;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import java.util.jar.Attributes;
import java.util.jar.Manifest;

import jakarta.servlet.ServletContext;

import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.Jar;
import org.apache.tomcat.JarScanFilter;
import org.apache.tomcat.JarScanType;
import org.apache.tomcat.JarScanner;
import org.apache.tomcat.JarScannerCallback;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.buf.UriUtil;
import org.apache.tomcat.util.compat.JreCompat;
import org.apache.tomcat.util.res.StringManager;

/**
 * The default {@link JarScanner} implementation scans the WEB-INF/lib directory
 * followed by the provided classloader and then works up the classloader
 * hierarchy. This implementation is sufficient to meet the requirements of the
 * Servlet 3.0 specification as well as to provide a number of Tomcat specific
 * extensions. The extensions are:
 * 
    *
  • Scanning the classloader hierarchy (enabled by default)
  • *
  • Testing all files to see if they are JARs (disabled by default)
  • *
  • Testing all directories to see if they are exploded JARs * (disabled by default)
  • *
* All of the extensions may be controlled via configuration. */ public class StandardJarScanner implements JarScanner { private final Log log = LogFactory.getLog(StandardJarScanner.class); // must not be static /** * The string resources for this package. */ private static final StringManager sm = StringManager.getManager(Constants.Package); private static final Set CLASSLOADER_HIERARCHY; static { Set cls = new HashSet<>(); ClassLoader cl = StandardJarScanner.class.getClassLoader(); while (cl != null) { cls.add(cl); cl = cl.getParent(); } CLASSLOADER_HIERARCHY = Collections.unmodifiableSet(cls); } /** * Controls the classpath scanning extension. */ private boolean scanClassPath = true; public boolean isScanClassPath() { return scanClassPath; } public void setScanClassPath(boolean scanClassPath) { this.scanClassPath = scanClassPath; } /** * Controls the JAR file Manifest scanning extension. */ private boolean scanManifest = true; public boolean isScanManifest() { return scanManifest; } public void setScanManifest(boolean scanManifest) { this.scanManifest = scanManifest; } /** * Controls the testing all files to see of they are JAR files extension. */ private boolean scanAllFiles = false; public boolean isScanAllFiles() { return scanAllFiles; } public void setScanAllFiles(boolean scanAllFiles) { this.scanAllFiles = scanAllFiles; } /** * Controls the testing all directories to see of they are exploded JAR * files extension. */ private boolean scanAllDirectories = true; public boolean isScanAllDirectories() { return scanAllDirectories; } public void setScanAllDirectories(boolean scanAllDirectories) { this.scanAllDirectories = scanAllDirectories; } /** * Controls the testing of the bootstrap classpath which consists of the * runtime classes provided by the JVM and any installed system extensions. */ private boolean scanBootstrapClassPath = false; public boolean isScanBootstrapClassPath() { return scanBootstrapClassPath; } public void setScanBootstrapClassPath(boolean scanBootstrapClassPath) { this.scanBootstrapClassPath = scanBootstrapClassPath; } /** * Controls the filtering of the results from the scan for JARs */ private JarScanFilter jarScanFilter = new StandardJarScanFilter(); @Override public JarScanFilter getJarScanFilter() { return jarScanFilter; } @Override public void setJarScanFilter(JarScanFilter jarScanFilter) { this.jarScanFilter = jarScanFilter; } /** * Scan the provided ServletContext and class loader for JAR files. Each JAR * file found will be passed to the callback handler to be processed. * * @param scanType The type of JAR scan to perform. This is passed to * the filter which uses it to determine how to * filter the results * @param context The ServletContext - used to locate and access * WEB-INF/lib * @param callback The handler to process any JARs found */ @Override public void scan(JarScanType scanType, ServletContext context, JarScannerCallback callback) { if (log.isTraceEnabled()) { log.trace(sm.getString("jarScan.webinflibStart")); } if (jarScanFilter.isSkipAll()) { return; } Set processedURLs = new HashSet<>(); // Scan WEB-INF/lib Set dirList = context.getResourcePaths(Constants.WEB_INF_LIB); if (dirList != null) { for (String path : dirList) { if (path.endsWith(Constants.JAR_EXT) && getJarScanFilter().check(scanType, path.substring(path.lastIndexOf('/')+1))) { // Need to scan this JAR if (log.isDebugEnabled()) { log.debug(sm.getString("jarScan.webinflibJarScan", path)); } URL url = null; try { url = context.getResource(path); processedURLs.add(url); process(scanType, callback, url, path, true, null); } catch (IOException e) { log.warn(sm.getString("jarScan.webinflibFail", url), e); } } else { if (log.isTraceEnabled()) { log.trace(sm.getString("jarScan.webinflibJarNoScan", path)); } } } } // Scan WEB-INF/classes try { URL webInfURL = context.getResource(Constants.WEB_INF_CLASSES); if (webInfURL != null) { // WEB-INF/classes will also be included in the URLs returned // by the web application class loader so ensure the class path // scanning below does not re-scan this location. processedURLs.add(webInfURL); if (isScanAllDirectories()) { URL url = context.getResource(Constants.WEB_INF_CLASSES + "/META-INF"); if (url != null) { try { callback.scanWebInfClasses(); } catch (IOException e) { log.warn(sm.getString("jarScan.webinfclassesFail"), e); } } } } } catch (MalformedURLException e) { // Ignore. Won't happen. URLs are of the correct form. } // Scan the classpath if (isScanClassPath()) { doScanClassPath(scanType, context, callback, processedURLs); } } protected void doScanClassPath(JarScanType scanType, ServletContext context, JarScannerCallback callback, Set processedURLs) { if (log.isTraceEnabled()) { log.trace(sm.getString("jarScan.classloaderStart")); } ClassLoader stopLoader = null; if (!isScanBootstrapClassPath()) { // Stop when we reach the bootstrap class loader stopLoader = ClassLoader.getSystemClassLoader().getParent(); } ClassLoader classLoader = context.getClassLoader(); // JARs are treated as application provided until the common class // loader is reached. boolean isWebapp = true; // Use a Deque so URLs can be removed as they are processed // and new URLs can be added as they are discovered during // processing. Deque classPathUrlsToProcess = new LinkedList<>(); while (classLoader != null && classLoader != stopLoader) { if (classLoader instanceof URLClassLoader) { if (isWebapp) { isWebapp = isWebappClassLoader(classLoader); } classPathUrlsToProcess.addAll( Arrays.asList(((URLClassLoader) classLoader).getURLs())); processURLs(scanType, callback, processedURLs, isWebapp, classPathUrlsToProcess); } classLoader = classLoader.getParent(); } if (JreCompat.isJre9Available()) { // The application and platform class loaders are not // instances of URLClassLoader. Use the class path in this // case. addClassPath(classPathUrlsToProcess); // Also add any modules JreCompat.getInstance().addBootModulePath(classPathUrlsToProcess); processURLs(scanType, callback, processedURLs, false, classPathUrlsToProcess); } } protected void processURLs(JarScanType scanType, JarScannerCallback callback, Set processedURLs, boolean isWebapp, Deque classPathUrlsToProcess) { if (jarScanFilter.isSkipAll()) { return; } while (!classPathUrlsToProcess.isEmpty()) { URL url = classPathUrlsToProcess.pop(); if (processedURLs.contains(url)) { // Skip this URL it has already been processed continue; } ClassPathEntry cpe = new ClassPathEntry(url); // JARs are scanned unless the filter says not to. // Directories are scanned for pluggability scans or // if scanAllDirectories is enabled unless the // filter says not to. if ((cpe.isJar() || scanType == JarScanType.PLUGGABILITY || isScanAllDirectories()) && getJarScanFilter().check(scanType, cpe.getName())) { if (log.isDebugEnabled()) { log.debug(sm.getString("jarScan.classloaderJarScan", url)); } try { processedURLs.add(url); process(scanType, callback, url, null, isWebapp, classPathUrlsToProcess); } catch (IOException ioe) { log.warn(sm.getString("jarScan.classloaderFail", url), ioe); } } else { // JAR / directory has been skipped if (log.isTraceEnabled()) { log.trace(sm.getString("jarScan.classloaderJarNoScan", url)); } } } } protected void addClassPath(Deque classPathUrlsToProcess) { String classPath = System.getProperty("java.class.path"); if (classPath == null || classPath.length() == 0) { return; } String[] classPathEntries = classPath.split(File.pathSeparator); for (String classPathEntry : classPathEntries) { File f = new File(classPathEntry); try { classPathUrlsToProcess.add(f.toURI().toURL()); } catch (MalformedURLException e) { log.warn(sm.getString("jarScan.classPath.badEntry", classPathEntry), e); } } } /* * Since class loader hierarchies can get complicated, this method attempts * to apply the following rule: A class loader is a web application class * loader unless it loaded this class (StandardJarScanner) or is a parent * of the class loader that loaded this class. * * This should mean: * the webapp class loader is an application class loader * the shared class loader is an application class loader * the server class loader is not an application class loader * the common class loader is not an application class loader * the system class loader is not an application class loader * the bootstrap class loader is not an application class loader */ private static boolean isWebappClassLoader(ClassLoader classLoader) { return !CLASSLOADER_HIERARCHY.contains(classLoader); } /* * Scan a URL for JARs with the optional extensions to look at all files * and all directories. */ protected void process(JarScanType scanType, JarScannerCallback callback, URL url, String webappPath, boolean isWebapp, Deque classPathUrlsToProcess) throws IOException { if (log.isTraceEnabled()) { log.trace(sm.getString("jarScan.jarUrlStart", url)); } if ("jar".equals(url.getProtocol()) || url.getPath().endsWith(Constants.JAR_EXT)) { try (Jar jar = JarFactory.newInstance(url)) { if (isScanManifest()) { processManifest(jar, isWebapp, classPathUrlsToProcess); } callback.scan(jar, webappPath, isWebapp); } } else if ("file".equals(url.getProtocol())) { File f; try { f = new File(url.toURI()); if (f.isFile() && isScanAllFiles()) { // Treat this file as a JAR URL jarURL = UriUtil.buildJarUrl(f); try (Jar jar = JarFactory.newInstance(jarURL)) { if (isScanManifest()) { processManifest(jar, isWebapp, classPathUrlsToProcess); } callback.scan(jar, webappPath, isWebapp); } } else if (f.isDirectory()) { if (scanType == JarScanType.PLUGGABILITY) { callback.scan(f, webappPath, isWebapp); } else { File metainf = new File(f.getAbsoluteFile() + File.separator + "META-INF"); if (metainf.isDirectory()) { callback.scan(f, webappPath, isWebapp); } } } } catch (Throwable t) { ExceptionUtils.handleThrowable(t); // Wrap the exception and re-throw throw new IOException(t); } } } private void processManifest(Jar jar, boolean isWebapp, Deque classPathUrlsToProcess) throws IOException { // Not processed for web application JARs nor if the caller did not // provide a Deque of URLs to append to. if (isWebapp || classPathUrlsToProcess == null) { return; } Manifest manifest = jar.getManifest(); if (manifest != null) { Attributes attributes = manifest.getMainAttributes(); String classPathAttribute = attributes.getValue("Class-Path"); if (classPathAttribute == null) { return; } String[] classPathEntries = classPathAttribute.split(" "); for (String classPathEntry : classPathEntries) { classPathEntry = classPathEntry.trim(); if (classPathEntry.length() == 0) { continue; } URL jarURL = jar.getJarFileURL(); URL classPathEntryURL; try { URI jarURI = jarURL.toURI(); /* * Note: Resolving the relative URLs from the manifest has the * potential to introduce security concerns. However, since * only JARs provided by the container and NOT those provided * by web applications are processed, there should be no * issues. * If this feature is ever extended to include JARs provided * by web applications, checks should be added to ensure that * any relative URL does not step outside the web application. */ URI classPathEntryURI = jarURI.resolve(classPathEntry); classPathEntryURL = classPathEntryURI.toURL(); } catch (Exception e) { if (log.isDebugEnabled()) { log.debug(sm.getString("jarScan.invalidUri", jarURL), e); } continue; } classPathUrlsToProcess.add(classPathEntryURL); } } } private static class ClassPathEntry { private final boolean jar; private final String name; public ClassPathEntry(URL url) { String path = url.getPath(); int end = path.lastIndexOf(Constants.JAR_EXT); if (end != -1) { jar = true; int start = path.lastIndexOf('/', end); name = path.substring(start + 1, end + 4); } else { jar = false; if (path.endsWith("/")) { path = path.substring(0, path.length() - 1); } int start = path.lastIndexOf('/'); name = path.substring(start + 1); } } public boolean isJar() { return jar; } public String getName() { return name; } } }




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