1 /*
   2  * Copyright (c) 2005, 2013, 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.jstack;
  27 
  28 import java.io.InputStream;
  29 import java.util.Collection;
  30 
  31 import com.sun.tools.attach.VirtualMachine;
  32 import com.sun.tools.attach.VirtualMachineDescriptor;
  33 import sun.tools.attach.HotSpotVirtualMachine;
  34 import sun.tools.common.ProcessArgumentMatcher;
  35 
  36 /*
  37  * This class is the main class for the JStack utility. It parses its arguments
  38  * and decides if the command should be executed by the SA JStack tool or by
  39  * obtained the thread dump from a target process using the VM attach mechanism
  40  */
  41 public class JStack {
  42 
  43     public static void main(String[] args) throws Exception {
  44         if (args.length == 0) {
  45             usage(1); // no arguments
  46         }
  47 
  48         checkForUnsupportedOptions(args);
  49 
  50         boolean locks = false;
  51 
  52         // Parse the options (arguments starting with "-" )
  53         int optionCount = 0;
  54         while (optionCount < args.length) {
  55             String arg = args[optionCount];
  56             if (!arg.startsWith("-")) {
  57                 break;
  58             }
  59             if (arg.equals("-help") || arg.equals("-h")) {
  60                 usage(0);
  61             }
  62             else {
  63                 if (arg.equals("-l")) {
  64                     locks = true;
  65                 } else {
  66                     usage(1);
  67                 }
  68             }
  69             optionCount++;
  70         }
  71 
  72         // Next we check the parameter count.
  73         int paramCount = args.length - optionCount;
  74         if (paramCount != 1) {
  75             usage(1);
  76         }
  77 
  78         // pass -l to thread dump operation to get extra lock info
  79         String pidArg = args[optionCount];
  80         String params[];
  81         if (locks) {
  82             params = new String[] { "-l" };
  83         } else {
  84             params = new String[0];
  85         }
  86         ProcessArgumentMatcher ap = new ProcessArgumentMatcher(pidArg);
  87         Collection<String> pids = ap.getVirtualMachinePids(JStack.class);
  88 
  89         if (pids.isEmpty()) {
  90             System.err.println("Could not find any processes matching : '" + pidArg + "'");
  91             System.exit(1);
  92         }
  93 
  94         for (String pid : pids) {
  95             if (pids.size() > 1) {
  96                 System.out.println("Pid:" + pid);
  97             }
  98             runThreadDump(pid, params);
  99         }
 100     }
 101 
 102     // Attach to pid and perform a thread dump
 103     private static void runThreadDump(String pid, String args[]) throws Exception {
 104         VirtualMachine vm = null;
 105         try {
 106             vm = VirtualMachine.attach(pid);
 107         } catch (Exception x) {
 108             String msg = x.getMessage();
 109             if (msg != null) {
 110                 System.err.println(pid + ": " + msg);
 111             } else {
 112                 x.printStackTrace();
 113             }
 114             System.exit(1);
 115         }
 116 
 117         // Cast to HotSpotVirtualMachine as this is implementation specific
 118         // method.
 119         InputStream in = ((HotSpotVirtualMachine)vm).remoteDataDump((Object[])args);
 120 
 121         // read to EOF and just print output
 122         byte b[] = new byte[256];
 123         int n;
 124         do {
 125             n = in.read(b);
 126             if (n > 0) {
 127                 String s = new String(b, 0, n, "UTF-8");
 128                 System.out.print(s);
 129             }
 130         } while (n > 0);
 131         in.close();
 132         vm.detach();
 133     }
 134 
 135     private static void checkForUnsupportedOptions(String[] args) {
 136         // Check arguments for -F, -m, and non-numeric value
 137         // and warn the user that SA is not supported anymore
 138 
 139         int paramCount = 0;
 140 
 141         for (String s : args) {
 142             if (s.equals("-F")) {
 143                 SAOptionError("-F option used");
 144             }
 145 
 146             if (s.equals("-m")) {
 147                 SAOptionError("-m option used");
 148             }
 149 
 150             if (! s.startsWith("-")) {
 151                 paramCount += 1;
 152             }
 153         }
 154 
 155         if (paramCount > 1) {
 156             SAOptionError("More than one non-option argument");
 157         }
 158     }
 159 
 160     private static void SAOptionError(String msg) {
 161         System.err.println("Error: " + msg);
 162         System.err.println("Cannot connect to core dump or remote debug server. Use jhsdb jstack instead");
 163         System.exit(1);
 164     }
 165 
 166     // print usage message
 167     private static void usage(int exit) {
 168         System.err.println("Usage:");
 169         System.err.println("    jstack [-l] <pid>");
 170         System.err.println("        (to connect to running process)");
 171         System.err.println("");
 172         System.err.println("Options:");
 173         System.err.println("    -l  long listing. Prints additional information about locks");
 174         System.err.println("    -h or -help to print this help message");
 175         System.exit(exit);
 176     }
 177 }