/*
 * Copyright (c) 2016, 2017, 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 jdk.internal.jrtfs;

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.channels.*;
import java.nio.file.*;
import java.nio.file.DirectoryStream.Filter;
import java.nio.file.attribute.*;
import java.nio.file.spi.FileSystemProvider;
import java.net.URI;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.ExecutorService;

File system provider for jrt file systems. Conditionally creates jrt fs on .jimage file or exploded modules directory of underlying JDK.
Implementation Note:This class needs to maintain JDK 8 source compatibility. It is used internally in the JDK to implement jimage/jrtfs access, but also compiled and delivered as part of the jrtfs.jar to support access to the jimage file provided by the shipped JDK by tools running on JDK 8.
/** * File system provider for jrt file systems. Conditionally creates jrt fs on * .jimage file or exploded modules directory of underlying JDK. * * @implNote This class needs to maintain JDK 8 source compatibility. * * It is used internally in the JDK to implement jimage/jrtfs access, * but also compiled and delivered as part of the jrtfs.jar to support access * to the jimage file provided by the shipped JDK by tools running on JDK 8. */
public final class JrtFileSystemProvider extends FileSystemProvider { private volatile FileSystem theFileSystem; public JrtFileSystemProvider() { } @Override public String getScheme() { return "jrt"; }
Need RuntimePermission "accessSystemModules" to create or get jrt:/
/** * Need RuntimePermission "accessSystemModules" to create or get jrt:/ */
private void checkPermission() { SecurityManager sm = System.getSecurityManager(); if (sm != null) { RuntimePermission perm = new RuntimePermission("accessSystemModules"); sm.checkPermission(perm); } } private void checkUri(URI uri) { if (!uri.getScheme().equalsIgnoreCase(getScheme())) { throw new IllegalArgumentException("URI does not match this provider"); } if (uri.getAuthority() != null) { throw new IllegalArgumentException("Authority component present"); } if (uri.getPath() == null) { throw new IllegalArgumentException("Path component is undefined"); } if (!uri.getPath().equals("/")) { throw new IllegalArgumentException("Path component should be '/'"); } if (uri.getQuery() != null) { throw new IllegalArgumentException("Query component present"); } if (uri.getFragment() != null) { throw new IllegalArgumentException("Fragment component present"); } } @Override public FileSystem newFileSystem(URI uri, Map<String, ?> env) throws IOException { Objects.requireNonNull(env); checkPermission(); checkUri(uri); if (env.containsKey("java.home")) { return newFileSystem((String)env.get("java.home"), uri, env); } else { return new JrtFileSystem(this, env); } } private static final String JRT_FS_JAR = "jrt-fs.jar"; private FileSystem newFileSystem(String targetHome, URI uri, Map<String, ?> env) throws IOException { Objects.requireNonNull(targetHome); Path jrtfs = FileSystems.getDefault().getPath(targetHome, "lib", JRT_FS_JAR); if (Files.notExists(jrtfs)) { throw new IOException(jrtfs.toString() + " not exist"); } Map<String,?> newEnv = new HashMap<>(env); newEnv.remove("java.home"); ClassLoader cl = newJrtFsLoader(jrtfs); try { Class<?> c = Class.forName(JrtFileSystemProvider.class.getName(), false, cl); @SuppressWarnings("deprecation") Object tmp = c.newInstance(); return ((FileSystemProvider)tmp).newFileSystem(uri, newEnv); } catch (ClassNotFoundException | IllegalAccessException | InstantiationException e) { throw new IOException(e); } } private static class JrtFsLoader extends URLClassLoader { JrtFsLoader(URL[] urls) { super(urls); } @Override protected Class<?> loadClass(String cn, boolean resolve) throws ClassNotFoundException { Class<?> c = findLoadedClass(cn); if (c == null) { URL u = findResource(cn.replace('.', '/') + ".class"); if (u != null) { c = findClass(cn); } else { return super.loadClass(cn, resolve); } } if (resolve) resolveClass(c); return c; } } private static URLClassLoader newJrtFsLoader(Path jrtfs) { final URL url; try { url = jrtfs.toUri().toURL(); } catch (MalformedURLException mue) { throw new IllegalArgumentException(mue); } final URL[] urls = new URL[] { url }; return AccessController.doPrivileged( new PrivilegedAction<URLClassLoader>() { @Override public URLClassLoader run() { return new JrtFsLoader(urls); } } ); } @Override public Path getPath(URI uri) { checkPermission(); if (!uri.getScheme().equalsIgnoreCase(getScheme())) { throw new IllegalArgumentException("URI does not match this provider"); } if (uri.getAuthority() != null) { throw new IllegalArgumentException("Authority component present"); } if (uri.getQuery() != null) { throw new IllegalArgumentException("Query component present"); } if (uri.getFragment() != null) { throw new IllegalArgumentException("Fragment component present"); } String path = uri.getPath(); if (path == null || path.charAt(0) != '/' || path.contains("..")) { throw new IllegalArgumentException("Invalid path component"); } return getTheFileSystem().getPath("/modules" + path); } private FileSystem getTheFileSystem() { checkPermission(); FileSystem fs = this.theFileSystem; if (fs == null) { synchronized (this) { fs = this.theFileSystem; if (fs == null) { try { this.theFileSystem = fs = new JrtFileSystem(this, null); } catch (IOException ioe) { throw new InternalError(ioe); } } } } return fs; } @Override public FileSystem getFileSystem(URI uri) { checkPermission(); checkUri(uri); return getTheFileSystem(); } // Checks that the given file is a JrtPath static final JrtPath toJrtPath(Path path) { Objects.requireNonNull(path, "path"); if (!(path instanceof JrtPath)) { throw new ProviderMismatchException(); } return (JrtPath) path; } @Override public void checkAccess(Path path, AccessMode... modes) throws IOException { toJrtPath(path).checkAccess(modes); } @Override public Path readSymbolicLink(Path link) throws IOException { return toJrtPath(link).readSymbolicLink(); } @Override public void copy(Path src, Path target, CopyOption... options) throws IOException { toJrtPath(src).copy(toJrtPath(target), options); } @Override public void createDirectory(Path path, FileAttribute<?>... attrs) throws IOException { toJrtPath(path).createDirectory(attrs); } @Override public final void delete(Path path) throws IOException { toJrtPath(path).delete(); } @Override @SuppressWarnings("unchecked") public <V extends FileAttributeView> V getFileAttributeView(Path path, Class<V> type, LinkOption... options) { return JrtFileAttributeView.get(toJrtPath(path), type, options); } @Override public FileStore getFileStore(Path path) throws IOException { return toJrtPath(path).getFileStore(); } @Override public boolean isHidden(Path path) { return toJrtPath(path).isHidden(); } @Override public boolean isSameFile(Path path, Path other) throws IOException { return toJrtPath(path).isSameFile(other); } @Override public void move(Path src, Path target, CopyOption... options) throws IOException { toJrtPath(src).move(toJrtPath(target), options); } @Override public AsynchronousFileChannel newAsynchronousFileChannel(Path path, Set<? extends OpenOption> options, ExecutorService exec, FileAttribute<?>... attrs) throws IOException { throw new UnsupportedOperationException(); } @Override public SeekableByteChannel newByteChannel(Path path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException { return toJrtPath(path).newByteChannel(options, attrs); } @Override public DirectoryStream<Path> newDirectoryStream( Path path, Filter<? super Path> filter) throws IOException { return toJrtPath(path).newDirectoryStream(filter); } @Override public FileChannel newFileChannel(Path path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException { return toJrtPath(path).newFileChannel(options, attrs); } @Override public InputStream newInputStream(Path path, OpenOption... options) throws IOException { return toJrtPath(path).newInputStream(options); } @Override public OutputStream newOutputStream(Path path, OpenOption... options) throws IOException { return toJrtPath(path).newOutputStream(options); } @Override @SuppressWarnings("unchecked") // Cast to A public <A extends BasicFileAttributes> A readAttributes(Path path, Class<A> type, LinkOption... options) throws IOException { if (type == BasicFileAttributes.class || type == JrtFileAttributes.class) { return (A) toJrtPath(path).getAttributes(options); } return null; } @Override public Map<String, Object> readAttributes(Path path, String attribute, LinkOption... options) throws IOException { return toJrtPath(path).readAttributes(attribute, options); } @Override public void setAttribute(Path path, String attribute, Object value, LinkOption... options) throws IOException { toJrtPath(path).setAttribute(attribute, value, options); } }