/*

 * 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.jstack;

import java.io.InputStream;

import java.util.Collection;

import com.sun.tools.attach.VirtualMachine;

import com.sun.tools.attach.VirtualMachineDescriptor;

import sun.tools.attach.HotSpotVirtualMachine;

import sun.tools.common.ProcessArgumentMatcher;

/*

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

 * and decides if the command should be executed by the SA JStack tool or by

 * obtained the thread dump from a target process using the VM attach mechanism

 */

public class JStack {

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

        if (args.length == 0) {

            usage(1); // no arguments

        }

        checkForUnsupportedOptions(args);

        boolean locks = false;

        // Parse the options (arguments starting with "-" )

        int optionCount = 0;

        while (optionCount < args.length) {

            String arg = args[optionCount];

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

                break;

            }

                usage(0);

            }

            else {

                if (arg.equals("-l")) {

                    locks = true;

                } else {

                    usage(1);

                }

            }

            optionCount++;

        }

        // Next we check the parameter count.

        int paramCount = args.length - optionCount;

        if (paramCount != 1) {

            usage(1);

        }

        // pass -l to thread dump operation to get extra lock info

        String pidArg = args[optionCount];

        String params[];

        if (locks) {

            params = new String[] { "-l" };

        } else {

            params = new String[0];

        }

        ProcessArgumentMatcher ap = new ProcessArgumentMatcher(pidArg);

        Collection<String> pids = ap.getVirtualMachinePids(JStack.class);

        if (pids.isEmpty()) {

            System.err.println("Could not find any processes matching : '" + pidArg + "'");

            System.exit(1);

        }

        for (String pid : pids) {

            if (pids.size() > 1) {

                System.out.println("Pid:" + pid);

            }

            runThreadDump(pid, params);

        }

    }

    // Attach to pid and perform a thread dump

    private static void runThreadDump(String pid, String args[]) throws Exception {

        VirtualMachine vm = null;

        try {

            vm = VirtualMachine.attach(pid);

        } catch (Exception x) {

            String msg = x.getMessage();

            if (msg != null) {

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

            } else {

                x.printStackTrace();

            }

            System.exit(1);

        }

        // Cast to HotSpotVirtualMachine as this is implementation specific

        // method.

        InputStream in = ((HotSpotVirtualMachine)vm).remoteDataDump((Object[])args);

        // 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();

    }

    private static void checkForUnsupportedOptions(String[] args) {

        // Check arguments for -F, -m, and non-numeric value

        // and warn the user that SA is not supported anymore

        int paramCount = 0;

        for (String s : args) {

            if (s.equals("-F")) {

                SAOptionError("-F option used");

            }

            if (s.equals("-m")) {

                SAOptionError("-m option used");

            }

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

                paramCount += 1;

            }

        }

        if (paramCount > 1) {

            SAOptionError("More than one non-option argument");

        }

    }

    private static void SAOptionError(String msg) {

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

        System.err.println("Cannot connect to core dump or remote debug server. Use jhsdb jstack instead");

        System.exit(1);

    }

    // print usage message

    private static void usage(int exit) {

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

        System.err.println("    jstack [-l] <pid>");

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

        System.err.println("");

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

        System.err.println("    -l  long listing. Prints additional information about locks");

        System.exit(exit);

    }

}