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