/*

 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.tools.jmap;

import java.lang.reflect.Method;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import com.sun.tools.attach.VirtualMachine;

import com.sun.tools.attach.AttachNotSupportedException;

import sun.tools.attach.HotSpotVirtualMachine;

/*

 * This class is the main class for the JMap utility. It parses its arguments

 * and decides if the command should be satisfied using the VM attach mechanism

 * or an SA tool. At this time the only option that uses the VM attach mechanism

 * is the -dump option to get a heap dump of a running application. All other

 * options are mapped to SA tools.

 */

public class JMap {

    // Options handled by the attach mechanism

    private static String HISTO_OPTION = "-histo";

    private static String LIVE_HISTO_OPTION = "-histo:live";

    private static String DUMP_OPTION_PREFIX = "-dump:";

    // These options imply the use of a SA tool

    private static String SA_TOOL_OPTIONS =

      "-heap|-heap:format=b|-clstats|-finalizerinfo";

    // The -F (force) option is currently not passed through to SA

    private static String FORCE_SA_OPTION = "-F";

    // Default option (if nothing provided)

    private static String DEFAULT_OPTION = "-pmap";

    public static void main(String[] args) throws Exception {

        if (args.length == 0) {

            usage(1); // no arguments

        }

        // used to indicate if we should use SA

        boolean useSA = false;

        // the chosen option (-heap, -dump:*, ... )

        String option = null;

        // First iterate over the options (arguments starting with -).  There should be

        // one (but maybe two if -F is also used).

        int optionCount = 0;

        while (optionCount < args.length) {

            String arg = args[optionCount];

            if (!arg.startsWith("-")) {

                break;

            }

            if (arg.equals("-help") || arg.equals("-h")) {

                usage(0);

            } else if (arg.equals(FORCE_SA_OPTION)) {

                useSA = true;

            } else {

                if (option != null) {

                    usage(1);  // option already specified

                }

                option = arg;

            }

            optionCount++;

        }

        // if no option provided then use default.

        if (option == null) {

            option = DEFAULT_OPTION;

        }

        if (option.matches(SA_TOOL_OPTIONS)) {

            useSA = true;

        }

        // Next we check the parameter count. For the SA tools there are

        // one or two parameters. For the built-in -dump option there is

        // only one parameter (the process-id)

        int paramCount = args.length - optionCount;

        if (paramCount == 0 || paramCount > 2) {

            usage(1);

        }

        if (optionCount == 0 || paramCount != 1) {

            useSA = true;

        } else {

            // the parameter for the -dump option is a process-id.

            // If it doesn't parse to a number then it must be SA

            // debug server

            if (!args[optionCount].matches("[0-9]+")) {

                useSA = true;

            }

        }

        // at this point we know if we are executing an SA tool or a built-in

        // option.

        if (useSA) {

            // parameters (<pid> or <exe> <core>)

            String params[] = new String[paramCount];

            for (int i=optionCount; i<args.length; i++ ){

                params[i-optionCount] = args[i];

            }

            runTool(option, params);

        } else {

            String pid = args[1];

            // Here we handle the built-in options

            // As more options are added we should create an abstract tool class and

            // have a table to map the options

            if (option.equals(HISTO_OPTION)) {

                histo(pid, false);

            } else if (option.equals(LIVE_HISTO_OPTION)) {

                histo(pid, true);

            } else if (option.startsWith(DUMP_OPTION_PREFIX)) {

                dump(pid, option);

            } else {

                usage(1);

            }

        }

    }

    // Invoke SA tool  with the given arguments

    private static void runTool(String option, String args[]) throws Exception {

        String[][] tools = {

            { "-pmap",          "sun.jvm.hotspot.tools.PMap"             },

            { "-heap",          "sun.jvm.hotspot.tools.HeapSummary"      },

            { "-heap:format=b", "sun.jvm.hotspot.tools.HeapDumper"       },

            { "-histo",         "sun.jvm.hotspot.tools.ObjectHistogram"  },

            { "-clstats",       "sun.jvm.hotspot.tools.ClassLoaderStats" },

            { "-finalizerinfo", "sun.jvm.hotspot.tools.FinalizerInfo"    },

        };

        String tool = null;

        // -dump option needs to be handled in a special way

        if (option.startsWith(DUMP_OPTION_PREFIX)) {

            // first check that the option can be parsed

            String fn = parseDumpOptions(option);

            if (fn == null) {

                usage(1);

            }

            // tool for heap dumping

            tool = "sun.jvm.hotspot.tools.HeapDumper";

            // HeapDumper -f <file>

            args = prepend(fn, args);

            args = prepend("-f", args);

        } else {

            int i=0;

            while (i < tools.length) {

                if (option.equals(tools[i][0])) {

                    tool = tools[i][1];

                    break;

                }

                i++;

            }

        }

        if (tool == null) {

            usage(1);   // no mapping to tool

        }

        // Tool not available on this  platform.

        Class<?> c = loadClass(tool);

        if (c == null) {

            usage(1);

        }

        // invoke the main method with the arguments

        Method m = c.getDeclaredMethod("main", argTypes);

        Object[] invokeArgs = { args };

        m.invoke(null, invokeArgs);

    }

    // loads the given class using the system class loader

    private static Class<?> loadClass(String name) {

        //

        // We specify the system clas loader so as to cater for development

        // environments where this class is on the boot class path but sa-jdi.jar

        // is on the system class path. Once the JDK is deployed then both

        // tools.jar and sa-jdi.jar are on the system class path.

        //

        try {

            return Class.forName(name, true,

                                 ClassLoader.getSystemClassLoader());

        } catch (Exception x)  { }

        return null;

    }

    private static final String LIVE_OBJECTS_OPTION = "-live";

    private static final String ALL_OBJECTS_OPTION = "-all";

    private static void histo(String pid, boolean live) throws IOException {

        VirtualMachine vm = attach(pid);

        InputStream in = ((HotSpotVirtualMachine)vm).

            heapHisto(live ? LIVE_OBJECTS_OPTION : ALL_OBJECTS_OPTION);

        drain(vm, in);

    }

    private static void dump(String pid, String options) throws IOException {

        // parse the options to get the dump filename

        String filename = parseDumpOptions(options);

        if (filename == null) {

            usage(1);  // invalid options or no filename

        }

        // get the canonical path - important to avoid just passing

        // a "heap.bin" and having the dump created in the target VM

        // working directory rather than the directory where jmap

        // is executed.

        filename = new File(filename).getCanonicalPath();

        // dump live objects only or not

        boolean live = isDumpLiveObjects(options);

        VirtualMachine vm = attach(pid);

        System.out.println("Dumping heap to " + filename + " ...");

        InputStream in = ((HotSpotVirtualMachine)vm).

            dumpHeap((Object)filename,

                     (live ? LIVE_OBJECTS_OPTION : ALL_OBJECTS_OPTION));

        drain(vm, in);

    }

    // Parse the options to the -dump option. Valid options are format=b and

    // file=<file>. Returns <file> if provided. Returns null if <file> not

    // provided, or invalid option.

    private static String parseDumpOptions(String arg) {

        assert arg.startsWith(DUMP_OPTION_PREFIX);

        String filename = null;

        // options are separated by comma (,)

        String options[] = arg.substring(DUMP_OPTION_PREFIX.length()).split(",");

        for (int i=0; i<options.length; i++) {

            String option = options[i];

            if (option.equals("format=b")) {

                // ignore format (not needed at this time)

            } else if (option.equals("live")) {

                // a valid suboption

            } else {

                // file=<file> - check that <file> is specified

                if (option.startsWith("file=")) {

                    filename = option.substring(5);

                    if (filename.length() == 0) {

                        return null;

                    }

                } else {

                    return null;  // option not recognized

                }

            }

        }

        return filename;

    }

    private static boolean isDumpLiveObjects(String arg) {

        // options are separated by comma (,)

        String options[] = arg.substring(DUMP_OPTION_PREFIX.length()).split(",");

        for (String suboption : options) {

            if (suboption.equals("live")) {

                return true;

            }

        }

        return false;

    }

    // Attach to <pid>, existing if we fail to attach

    private static VirtualMachine attach(String pid) {

        try {

            return VirtualMachine.attach(pid);

        } catch (Exception x) {

            String msg = x.getMessage();

            if (msg != null) {

                System.err.println(pid + ": " + msg);

            } else {

                x.printStackTrace();

            }

            if ((x instanceof AttachNotSupportedException) && haveSA()) {

                System.err.println("The -F option can be used when the " +

                  "target process is not responding");

            }

            System.exit(1);

            return null; // keep compiler happy

        }

    }

    // Read the stream from the target VM until EOF, then detach

    private static void drain(VirtualMachine vm, InputStream in) throws IOException {

        // read to EOF and just print output

        byte b[] = new byte[256];

        int n;

        do {

            n = in.read(b);

            if (n > 0) {

                String s = new String(b, 0, n, "UTF-8");

                System.out.print(s);

            }

        } while (n > 0);

        in.close();

        vm.detach();

    }

    // return a new string array with arg as the first element

    private static String[] prepend(String arg, String args[]) {

        String[] newargs = new String[args.length+1];

        newargs[0] = arg;

        System.arraycopy(args, 0, newargs, 1, args.length);

        return newargs;

    }

    // returns true if SA is available

    private static boolean haveSA() {

        Class<?> c = loadClass("sun.jvm.hotspot.tools.HeapSummary");

        return (c != null);

    }

    // print usage message

    private static void usage(int exit) {

        System.err.println("Usage:");

        if (haveSA()) {

            System.err.println("    jmap [option] <pid>");

            System.err.println("        (to connect to running process)");

            System.err.println("    jmap [option] <executable <core>");

            System.err.println("        (to connect to a core file)");

            System.err.println("    jmap [option] [server_id@]<remote server IP or hostname>");

            System.err.println("        (to connect to remote debug server)");

            System.err.println("");

            System.err.println("where <option> is one of:");

            System.err.println("    <none>               to print same info as Solaris pmap");

            System.err.println("    -heap                to print java heap summary");

            System.err.println("    -histo[:live]        to print histogram of java object heap; if the \"live\"");

            System.err.println("                         suboption is specified, only count live objects");

            System.err.println("    -clstats             to print class loader statistics");

            System.err.println("    -finalizerinfo       to print information on objects awaiting finalization");

            System.err.println("    -dump:<dump-options> to dump java heap in hprof binary format");

            System.err.println("                         dump-options:");

            System.err.println("                           live         dump only live objects; if not specified,");

            System.err.println("                                        all objects in the heap are dumped.");

            System.err.println("                           format=b     binary format");

            System.err.println("                           file=<file>  dump heap to <file>");

            System.err.println("                         Example: jmap -dump:live,format=b,file=heap.bin <pid>");

            System.err.println("    -F                   force. Use with -dump:<dump-options> <pid> or -histo");

            System.err.println("                         to force a heap dump or histogram when <pid> does not");

            System.err.println("                         respond. The \"live\" suboption is not supported");

            System.err.println("                         in this mode.");

            System.err.println("    -h | -help           to print this help message");

            System.err.println("    -J<flag>             to pass <flag> directly to the runtime system");

        } else {

            System.err.println("    jmap -histo <pid>");

            System.err.println("      (to connect to running process and print histogram of java object heap");

            System.err.println("    jmap -dump:<dump-options> <pid>");

            System.err.println("      (to connect to running process and dump java heap)");

            System.err.println("");

            System.err.println("    dump-options:");

            System.err.println("      format=b     binary default");

            System.err.println("      file=<file>  dump heap to <file>");

            System.err.println("");

            System.err.println("    Example:       jmap -dump:format=b,file=heap.bin <pid>");

        }

        System.exit(exit);

    }

}