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 
  26 package sun.tools.jmap;
  27 
  28 import java.io.File;
  29 import java.io.IOException;
  30 import java.io.InputStream;
  31 import java.io.UnsupportedEncodingException;
  32 import java.util.Collection;
  33 
  34 import com.sun.tools.attach.VirtualMachine;
  35 import com.sun.tools.attach.VirtualMachineDescriptor;
  36 import com.sun.tools.attach.AttachNotSupportedException;
  37 import sun.tools.attach.HotSpotVirtualMachine;
  38 import sun.tools.common.ProcessArgumentMatcher;
  39 
  40 /*
  41  * This class is the main class for the JMap utility. It parses its arguments
  42  * and decides if the command should be satisfied using the VM attach mechanism
  43  * or an SA tool. At this time the only option that uses the VM attach mechanism
  44  * is the -dump option to get a heap dump of a running application. All other
  45  * options are mapped to SA tools.
  46  */
  47 public class JMap {
  48 
  49     public static void main(String[] args) throws Exception {
  50         if (args.length == 0) {
  51             usage(1); // no arguments
  52         }
  53 
  54         checkForUnsupportedOptions(args);
  55 
  56         // the chosen option
  57         String option = null;
  58 
  59         // First iterate over the options (arguments starting with -).  There should be
  60         // one.
  61         int optionCount = 0;
  62         while (optionCount < args.length) {
  63             String arg = args[optionCount];
  64             if (!arg.startsWith("-")) {
  65                 break;
  66             }
  67             if (arg.equals("-?") ||
  68                 arg.equals("-h") ||
  69                 arg.equals("--help") ||
  70                 // -help: legacy. Undocumented.
  71                 arg.equals("-help")) {
  72                 usage(0);
  73             } else {
  74                 if (option != null) {
  75                     usage(1);  // option already specified
  76                 }
  77                 option = arg;
  78             }
  79             optionCount++;
  80         }
  81 
  82         // if no option provided then use default.
  83         if (option == null) {
  84             usage(0);
  85         }
  86 
  87         // Next we check the parameter count.
  88         int paramCount = args.length - optionCount;
  89         if (paramCount != 1) {
  90             usage(1);
  91         }
  92 
  93         String pidArg = args[1];
  94         // Here we handle the built-in options
  95         // As more options are added we should create an abstract tool class and
  96         // have a table to map the options
  97         ProcessArgumentMatcher ap = new ProcessArgumentMatcher(pidArg);
  98         Collection<String> pids = ap.getVirtualMachinePids(JMap.class);
  99 
 100         if (pids.isEmpty()) {
 101             System.err.println("Could not find any processes matching : '" + pidArg + "'");
 102             System.exit(1);
 103         }
 104 
 105         for (String pid : pids) {
 106             if (pids.size() > 1) {
 107                 System.out.println("Pid:" + pid);
 108             }
 109             if (option.equals("-histo")) {
 110                 histo(pid, "");
 111             } else if (option.startsWith("-histo:")) {
 112                 histo(pid, option.substring("-histo:".length()));
 113             } else if (option.startsWith("-dump:")) {
 114                 dump(pid, option.substring("-dump:".length()));
 115             } else if (option.equals("-finalizerinfo")) {
 116                 executeCommandForPid(pid, "jcmd", "GC.finalizer_info");
 117             } else if (option.equals("-clstats")) {
 118                 executeCommandForPid(pid, "jcmd", "VM.classloader_stats");
 119             } else {
 120               usage(1);
 121             }
 122         }
 123     }
 124 
 125     private static void executeCommandForPid(String pid, String command, Object ... args)
 126         throws AttachNotSupportedException, IOException,
 127                UnsupportedEncodingException {
 128         VirtualMachine vm = VirtualMachine.attach(pid);
 129 
 130         // Cast to HotSpotVirtualMachine as this is an
 131         // implementation specific method.
 132         HotSpotVirtualMachine hvm = (HotSpotVirtualMachine) vm;
 133         try (InputStream in = hvm.executeCommand(command, args)) {
 134           // read to EOF and just print output
 135           byte b[] = new byte[256];
 136           int n;
 137           do {
 138               n = in.read(b);
 139               if (n > 0) {
 140                   String s = new String(b, 0, n, "UTF-8");
 141                   System.out.print(s);
 142               }
 143           } while (n > 0);
 144         }
 145         vm.detach();
 146     }
 147 
 148     private static String parseFileName(String opt) {
 149         // opt starts with "file="
 150         if (opt.length() > 5) {
 151             //  pass whole "file=" string
 152             String filename = opt.substring(5);
 153             try {
 154                 // Get the canonical path - important to avoid just
 155                 // passing a "heap.bin" and having the dump created
 156                 // in the target VM working directory rather than the
 157                 // directory where jmap is executed.
 158                 return new File(filename).getCanonicalPath();
 159             } catch (IOException ioe) {
 160               return null;
 161             }
 162         }
 163         // no filename
 164         return null;
 165     }
 166 
 167     private static void histo(String pid, String options)
 168         throws AttachNotSupportedException, IOException,
 169                UnsupportedEncodingException {
 170         String liveopt = "-all";
 171         String filename = null;
 172         String subopts[] = options.split(",");
 173 
 174         for (int i = 0; i < subopts.length; i++) {
 175             String subopt = subopts[i];
 176             if (subopt.equals("") || subopt.equals("all")) {
 177                 // pass
 178             } else if (subopt.equals("live")) {
 179                 liveopt = "-live";
 180             } else if (subopt.startsWith("file=")) {
 181                 filename = parseFileName(subopt);
 182                 if (filename == null) {
 183                     usage(1); // invalid options or no filename
 184                 }
 185             } else {
 186                 usage(1);
 187             }
 188         }
 189 
 190         System.out.flush();
 191 
 192         // inspectHeap is not the same as jcmd GC.class_histogram
 193         executeCommandForPid(pid, "inspectheap", liveopt, filename);
 194     }
 195 
 196     private static void dump(String pid, String options)
 197         throws AttachNotSupportedException, IOException,
 198                UnsupportedEncodingException {
 199 
 200         String subopts[] = options.split(",");
 201         String filename = null;
 202         String liveopt = "-all";
 203 
 204         for (int i = 0; i < subopts.length; i++) {
 205             String subopt = subopts[i];
 206             if (subopt.equals("live")) {
 207                 liveopt = "-live";
 208             } else if (subopt.startsWith("file=")) {
 209                 filename = parseFileName(subopt);
 210             }
 211         }
 212 
 213         if (filename == null) {
 214             usage(1);  // invalid options or no filename
 215         }
 216 
 217         // dumpHeap is not the same as jcmd GC.heap_dump
 218         executeCommandForPid(pid, "dumpheap", filename, liveopt);
 219     }
 220 
 221     private static void checkForUnsupportedOptions(String[] args) {
 222         // Check arguments for -F, -m, and non-numeric value
 223         // and warn the user that SA is not supported anymore
 224 
 225         int paramCount = 0;
 226 
 227         for (String s : args) {
 228             if (s.equals("-F")) {
 229                 SAOptionError("-F option used");
 230             }
 231 
 232             if (s.equals("-heap")) {
 233                 SAOptionError("-heap option used");
 234             }
 235 
 236             /* Reimplemented using jcmd, output format is different
 237                from original one
 238 
 239             if (s.equals("-clstats")) {
 240                 warnSA("-clstats option used");
 241             }
 242 
 243             if (s.equals("-finalizerinfo")) {
 244                 warnSA("-finalizerinfo option used");
 245             }
 246             */
 247 
 248             if (! s.startsWith("-")) {
 249                 paramCount += 1;
 250             }
 251         }
 252 
 253         if (paramCount > 1) {
 254             SAOptionError("More than one non-option argument");
 255         }
 256     }
 257 
 258     private static void SAOptionError(String msg) {
 259         System.err.println("Error: " + msg);
 260         System.err.println("Cannot connect to core dump or remote debug server. Use jhsdb jmap instead");
 261         System.exit(1);
 262     }
 263 
 264     // print usage message
 265     private static void usage(int exit) {
 266         System.err.println("Usage:");
 267         System.err.println("    jmap -clstats <pid>");
 268         System.err.println("        to connect to running process and print class loader statistics");
 269         System.err.println("    jmap -finalizerinfo <pid>");
 270         System.err.println("        to connect to running process and print information on objects awaiting finalization");
 271         System.err.println("    jmap -histo[:[<histo-options>]] <pid>");
 272         System.err.println("        to connect to running process and print histogram of java object heap");
 273         System.err.println("    jmap -dump:<dump-options> <pid>");
 274         System.err.println("        to connect to running process and dump java heap");
 275         System.err.println("    jmap -? -h --help");
 276         System.err.println("        to print this help message");
 277         System.err.println("");
 278         System.err.println("    dump-options:");
 279         System.err.println("      live         dump only live objects");
 280         System.err.println("      all          dump all objects in the heap (default if one of \"live\" or \"all\" is not specified");
 281         System.err.println("      format=b     binary format");
 282         System.err.println("      file=<file>  dump heap to <file>");
 283         System.err.println("");
 284         System.err.println("    Example: jmap -dump:live,format=b,file=heap.bin <pid>");
 285         System.err.println("");
 286         System.err.println("    histo-options:");
 287         System.err.println("      live         count only live objects");
 288         System.err.println("      all          count all objects in the heap (default if one of \"live\" or \"all\" is not specified)");
 289         System.err.println("      file=<file>  dump data to <file>");
 290         System.err.println("");
 291         System.err.println("    Example: jmap -histo:live,file=/tmp/histo.data <pid>");
 292         System.exit(exit);
 293     }
 294 }