1 /*
   2  * Copyright (c) 2005, 2020, 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 package jdk.internal.vm;
  26 
  27 import java.io.IOException;
  28 import java.util.Properties;
  29 import java.util.jar.JarFile;
  30 import java.util.jar.Manifest;
  31 import java.util.jar.Attributes;
  32 import java.util.*;
  33 import java.nio.*;
  34 import java.nio.charset.*;
  35 
  36 /*
  37  * Support class used by JVMTI and VM attach mechanism.
  38  */
  39 public class VMSupport {
  40 
  41     private static Properties agentProps = null;
  42     /**
  43      * Returns the agent properties.
  44      */
  45     public static synchronized Properties getAgentProperties() {
  46         if (agentProps == null) {
  47             agentProps = new Properties();
  48             initAgentProperties(agentProps);
  49         }
  50         return agentProps;
  51     }
  52     private static native Properties initAgentProperties(Properties props);
  53 
  54     private static String convertToBytesStr(String str, boolean escapeSpace) throws Exception {
  55         if (escapeSpace) {
  56             str = str.replace(" ", "\\ ");
  57         }
  58 
  59         var charBuf = CharBuffer.wrap(str);
  60         var byteBuf = ByteBuffer.allocate(charBuf.length() * 5); // 1 unicode char might have 4 digits + 2 ('\u')
  61         var encoder = StandardCharsets.ISO_8859_1
  62                                       .newEncoder()
  63                                       .onUnmappableCharacter(CodingErrorAction.REPORT);
  64         CoderResult result;
  65         do {
  66             result = encoder.encode(charBuf, byteBuf, false);
  67             if (result.isUnmappable()) {
  68                 byteBuf.put(String.format("\\u%04X", (int)charBuf.get()).getBytes());
  69             } else if (result.isError()) {
  70                 result.throwException();
  71             }
  72         } while (result.isError());
  73 
  74         return new String(byteBuf.array());
  75     }
  76 
  77     /**
  78      * Write the given properties list to a byte array and return it. Properties with
  79      * a key or value that is not a String is filtered out. The stream written to the byte
  80      * array is ISO 8859-1 encoded.
  81      */
  82     private static byte[] serializePropertiesToByteArray(Properties p) throws IOException {
  83         var joiner = new StringJoiner("\n");
  84         joiner.add((new Date()).toString());
  85         for (var entry : p.entrySet()) {
  86             var key = convertToBytes(entry.getKey().toString(), true);
  87             var value = convertToBytes(entry.getValue().toString(), false);
  88             joiner.add(key + "=" + value);
  89         }
  90         return joiner.toString().getBytes();
  91     }
  92 
  93     public static byte[] serializePropertiesToByteArray() throws IOException {
  94         return serializePropertiesToByteArray(System.getProperties());
  95     }
  96 
  97     public static byte[] serializeAgentPropertiesToByteArray() throws IOException {
  98         return serializePropertiesToByteArray(getAgentProperties());
  99     }
 100 
 101     /*
 102      * Returns true if the given JAR file has the Class-Path attribute in the
 103      * main section of the JAR manifest. Throws RuntimeException if the given
 104      * path is not a JAR file or some other error occurs.
 105      */
 106     public static boolean isClassPathAttributePresent(String path) {
 107         try {
 108             Manifest man = (new JarFile(path)).getManifest();
 109             if (man != null) {
 110                 if (man.getMainAttributes().getValue(Attributes.Name.CLASS_PATH) != null) {
 111                     return true;
 112                 }
 113             }
 114             return false;
 115         } catch (IOException ioe) {
 116             throw new RuntimeException(ioe.getMessage());
 117         }
 118     }
 119 
 120     /*
 121      * Return the temporary directory that the VM uses for the attach
 122      * and perf data files.
 123      *
 124      * It is important that this directory is well-known and the
 125      * same for all VM instances. It cannot be affected by configuration
 126      * variables such as java.io.tmpdir.
 127      */
 128     public static native String getVMTemporaryDirectory();
 129 }