src/jdk.jcmd/linux/classes/sun/tools/ProcessHelper.java
changeset 58329 483f14c3e0a2
parent 58328 fe46ee1d42ee
parent 58311 88fce7eea1f6
child 58330 de8e08015d51
equal deleted inserted replaced
58328:fe46ee1d42ee 58329:483f14c3e0a2
     1 /*
       
     2  * Copyright (c) 2019, 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 sun.tools;
       
    27 
       
    28 import java.io.IOException;
       
    29 import java.io.UncheckedIOException;
       
    30 import java.nio.file.Files;
       
    31 import java.nio.file.Paths;
       
    32 import java.util.jar.Attributes;
       
    33 import java.util.jar.JarFile;
       
    34 import java.util.stream.Stream;
       
    35 
       
    36 /**
       
    37  * A helper class that retrieves the main class name for
       
    38  * a running Java process using the proc filesystem (procfs)
       
    39  */
       
    40 public class ProcessHelper implements sun.tools.common.ProcessHelper {
       
    41 
       
    42 
       
    43     private static final String CMD_PREFIX = "cmd:";
       
    44     private static final ProcessHelper INSTANCE = new ProcessHelper();
       
    45 
       
    46     public static ProcessHelper getInstance() {
       
    47         return INSTANCE;
       
    48     }
       
    49 
       
    50     /**
       
    51      * Gets the main class name for the given Java process by parsing the
       
    52      * process command line. If the application was started with the <em>-jar</em>
       
    53      * option this method returns the name of the jar file. If the application
       
    54      * was started with <em>-m</em> or <em>--module</em> option, the method returns
       
    55      * the module name and the main class name.
       
    56      * @param pid - process ID (pid)
       
    57      * @return the main class name or null if the process no longer exists or
       
    58      * was started with a native launcher (e.g. jcmd etc)
       
    59      */
       
    60 
       
    61     public String getMainClass(String pid) {
       
    62         String cmdLine = getCommandLine(pid);
       
    63         if (cmdLine == null) {
       
    64             return null;
       
    65         }
       
    66         if (cmdLine.startsWith(CMD_PREFIX)) {
       
    67             cmdLine = cmdLine.substring(CMD_PREFIX.length());
       
    68         }
       
    69         String[] parts = cmdLine.split("\0");
       
    70         String mainClass = null;
       
    71 
       
    72         if(parts.length == 0) {
       
    73             return null;
       
    74         }
       
    75 
       
    76         // Check the executable
       
    77         String[] executablePath = parts[0].split("/");
       
    78         if (executablePath.length > 0) {
       
    79             String binaryName = executablePath[executablePath.length - 1];
       
    80             if (!"java".equals(binaryName)) {
       
    81                 // Skip the process if it is not started with java launcher
       
    82                 return null;
       
    83             }
       
    84         }
       
    85 
       
    86         // To be consistent with the behavior on other platforms, if -jar, -m, or --module
       
    87         // options are used then just return the value (the path to the jar file or module
       
    88         // name with a main class). Otherwise, the main class name is the first part that
       
    89         // is not a Java option (doesn't start with '-' and is not a classpath or a module
       
    90         // whitespace option).
       
    91 
       
    92         for (int i = 1; i < parts.length && mainClass == null; i++) {
       
    93             if (i < parts.length - 1) {
       
    94                 if (parts[i].equals("-m") || parts[i].equals("--module") || parts[i].equals("-jar")) {
       
    95                     return parts[i + 1];
       
    96                 }
       
    97             }
       
    98 
       
    99             if (parts[i].startsWith("--module=")) {
       
   100                 return parts[i].substring("--module=".length());
       
   101             }
       
   102 
       
   103             // If this is a classpath or a module whitespace option then skip the next part
       
   104             // (the classpath or the option value itself)
       
   105             if (parts[i].equals("-cp") || parts[i].equals("-classpath") ||  parts[i].equals("--class-path") ||
       
   106                     isModuleWhiteSpaceOption(parts[i])) {
       
   107                 i++;
       
   108                 continue;
       
   109             }
       
   110             // Skip all other Java options
       
   111             if (parts[i].startsWith("-")) {
       
   112                 continue;
       
   113             }
       
   114 
       
   115             // If it is a source-file mode then return null
       
   116             if (parts[i].endsWith(".java")) {
       
   117                 return null;
       
   118             }
       
   119 
       
   120             mainClass = parts[i];
       
   121         }
       
   122         return mainClass;
       
   123 
       
   124     }
       
   125 
       
   126     private static String getCommandLine(String pid) {
       
   127         try (Stream<String> lines =
       
   128                      Files.lines(Paths.get("/proc/" + pid + "/cmdline"))) {
       
   129             return lines.findFirst().orElse(null);
       
   130         } catch (IOException | UncheckedIOException e) {
       
   131             return null;
       
   132         }
       
   133     }
       
   134 
       
   135     private static boolean isModuleWhiteSpaceOption(String option) {
       
   136         return option.equals("-p") ||
       
   137                 option.equals("--module-path") ||
       
   138                 option.equals("--upgrade-module-path") ||
       
   139                 option.equals("--add-modules") ||
       
   140                 option.equals("--limit-modules") ||
       
   141                 option.equals("--add-exports") ||
       
   142                 option.equals("--add-opens") ||
       
   143                 option.equals("--add-reads") ||
       
   144                 option.equals("--patch-module");
       
   145     }
       
   146 
       
   147 }
       
   148 
       
   149