PidUtils.java

/**
 *  Copyright (C) 2008 Progress Software, Inc. All rights reserved.
 *  http://fusesource.com
 *
 *  The software in this package is published under the terms of the AGPL license
 *  a copy of which has been included with this distribution in the license.txt file.
 */
package org.fusesource.cloudmix.agent;

import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.sun.jna.Native;
import com.sun.jna.Pointer;

import org.fusesource.cloudmix.agent.unix.Posix;
import org.fusesource.cloudmix.agent.win32.Kernel32;


public final class PidUtils {
    private static final String[] UNIX_COMMAND = {
        "sh", "-c", "echo $PPID"
    };
    private static final int PID = getPidInternal();

    private PidUtils() { /* static utility class */
    }

    public static int getPid() {
        return PID;
    }

    /**
     * @param pid
     * @return true if the provided pid is running.
     * @throws IOException
     */
    public static boolean isPidRunning(int pid) throws IOException {
        Kernel32 kernel32 = Kernel32.Factory.get();
        if (kernel32 != null) {
            Pointer process = kernel32.OpenProcess(Kernel32.SYNCHRONIZE, 0, pid);
            if (process != null) {
                int x = kernel32.WaitForSingleObject(process, 0);
                return x != Kernel32.WAIT_OBJECT_0;
            }
            return false;
        }

        Posix posix = Posix.Factory.get();
        if (posix != null) {
            return posix.kill(pid, 0) == 0;
        }
        throw new UnsupportedOperationException("isPidRunning is not yet supported"
                                                + " on this operating system.");
    }

    /**
     * Kills a running PID. If your on a Unix system, it kills it with the given signal, but if your on
     * Windows, you terminate the process with the provided exitCode.
     * 
     * @param pid
     * @param signal
     * @param exitCode
     * @throws IOException
     */
    public static void killPid(int pid, int signal, int exitCode) throws IOException {
        Kernel32 kernel32 = Kernel32.Factory.get();
        if (kernel32 != null) {
            Pointer process = kernel32.OpenProcess(Kernel32.PROCESS_TERMINATE, 0, pid);
            if (process == null) {
                throw new IOException("Could not open process pid " + pid + ": "
                                      + Kernel32.Factory.getLastErrorAsString());
            }
            try {
                if (kernel32.TerminateProcess(process, exitCode) == 0) {
                    throw new IOException("Could not terminate process pid " + pid + ": "
                                          + Kernel32.Factory.getLastErrorAsString());
                }
                return;
            } finally {
                kernel32.CloseHandle(process);
            }
        }

        Posix posix = Posix.Factory.get();
        if (posix != null) {
            if (posix.kill(pid, signal) != 0) {
                throw new IOException("Could not kill process pid " + pid + ": "
                                      + posix.strerror(Native.getLastError()));
            }
            return;
        }

        throw new UnsupportedOperationException("killPid is not yet supported on this operating system.");
    }

    private static int getPidInternal() {

        // Try to do a native system call call...
        Kernel32 kernel32 = Kernel32.Factory.get();
        if (kernel32 != null) {
            return kernel32.GetCurrentProcessId();
        }

        // Try to do a native system call call...
        Posix posix = Posix.Factory.get();
        if (posix != null) {
            return posix.getpid();
        }

        // Fall back to some JVM hacks..
        int id = getMXBeanPid();
        if (id != -1) {
            return id;
        }

        // Fall back to using some shell hacks..
        // on other platforms, try this
        return getPidFromShell();
    }

    private static int getMXBeanPid() {
        try {
            String name = ManagementFactory.getRuntimeMXBean().getName().trim();
            Pattern pattern = Pattern.compile("^(\\d*).*");
            Matcher matcher = pattern.matcher(name);
            if (matcher.matches()) {
                name = matcher.group(1);
                return Integer.parseInt(name);
            } else {
                return -1;
            }
        } catch (Throwable th) {
            return -1;
        }
    }

    private static int getPidFromShell() {
        try {
            Process p = Runtime.getRuntime().exec(UNIX_COMMAND);
            byte[] bytes = new byte[100];
            p.getInputStream().read(bytes);

            int value = Integer.parseInt(new String(bytes));
            if (value == 0) {
                value = -1;
            }
            return value;
        } catch (Throwable th) {
            return -1;
        }
    }
}