1 /*
   2  * Copyright (c) 2014, 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 jdk.internal.jrtfs;
  27 
  28 import java.net.URISyntaxException;
  29 import java.net.URL;
  30 import java.nio.file.FileSystem;
  31 import java.nio.file.FileSystems;
  32 import java.nio.file.Path;
  33 import java.nio.file.Paths;
  34 import java.security.AccessController;
  35 import java.security.CodeSource;
  36 import java.security.PrivilegedAction;
  37 
  38 final class SystemImages {
  39     private SystemImages() {}
  40 
  41     static final String RUNTIME_HOME;
  42     static final Path bootImagePath;
  43     static final Path extImagePath;
  44     static final Path appImagePath;
  45 
  46     static {
  47         PrivilegedAction<String> pa = SystemImages::findHome;
  48         RUNTIME_HOME = AccessController.doPrivileged(pa);
  49 
  50         FileSystem fs = FileSystems.getDefault();
  51         bootImagePath = fs.getPath(RUNTIME_HOME, "lib", "modules", "bootmodules.jimage");
  52         extImagePath = fs.getPath(RUNTIME_HOME, "lib", "modules", "extmodules.jimage");
  53         appImagePath = fs.getPath(RUNTIME_HOME, "lib", "modules", "appmodules.jimage");
  54     }
  55 
  56     /**
  57      * Returns the appropriate JDK home for this usage of the FileSystemProvider.
  58      * When the CodeSource is null (null loader) then jrt:/ is the current runtime,
  59      * otherwise the JDK home is located relative to jrt-fs.jar.
  60      */
  61     private static String findHome() {
  62         CodeSource cs = SystemImages.class.getProtectionDomain().getCodeSource();
  63         if (cs == null)
  64             return System.getProperty("java.home");
  65 
  66         // assume loaded from $TARGETJDK/jrt-fs.jar
  67         URL url = cs.getLocation();
  68         if (!url.getProtocol().equalsIgnoreCase("file"))
  69             throw new RuntimeException(url + " loaded in unexpected way");
  70         try {
  71             return Paths.get(url.toURI()).getParent().toString();
  72         } catch (URISyntaxException e) {
  73             throw new InternalError(e);
  74         }
  75     }
  76 }