Java ProcessBuilder process.destroy() not killing child processes in winXP

java

I have a java app that uses ProcessBuilder to prepare an operating system command and gives me a Process object. (The actual os command is rsync over ssh using cygwin).

This is working well in Windows, however if I want to stop the process using process.destroy() it will not kill the child ssh and rsync processes…..
I have to manually kill them using the windows task manager..

Is it possible to get the OutputStream of the process and send a ctrl-c somehow before I call destroy();?

If anyone has any ideas on a workaround it would be great.
Thanks,
D

Best Answer

I also think that emulating Ctrl-C in order to kill ssh entirely is problematic.

What I would do, is one of the following approaches. Either use windows commands to find out who are ssh's sons (which is a little bit problematic, since you need to know your current pid in order to recieve your own children-processes). I believe pstools of sysinternals is a good command-line tool that should enable you to track orphan processes. See this example for controlling windows processes either with taskList.exe (which can give you its output in CSV format BTW) or by executing a special VBScript.

The second approach is using a java library such as winp to execute and control the ssh process. I believe you'd be able to list all its children and forcibly kill them if sending the correct message would not suffice. This would be my preferred approach. Please note that the killRecursively method does exactly what you want.

Please note that those approaches should not render your application windows only. You can encapsulate those in a class that would run differently on Windows and linux machines.

Please note I didn't try to gain a fine-grained control on windows processes with, so I'm not sure how mature would those solutions I found are.

Related Solutions

Java tool/method to force-kill a child process

There is a leaner way to do this using Java JNA.

This works definitely for Windows and Linux, i assume that you can do the same for other platforms too.

The biggest problem of Java process handling is the lack of a method to get the process id of the process started with untime.getRuntime().exec().

Assuming you got the pid of a process, you always can start a kill -9 command in linux, or use similar ways to kill a process in windows.

Here is a way to get the process id natively for linux (borrowed from the selenium framework, :) ), and with the help of JNA this also can be done for windows (using native Windows API calls).

For this to work (for Windows) you first have to get the JNA Library at JAVA NATIVE ACCESS (JNA): Downloads or get it from maven

Look at the following code, which will get the pid of a (in this example windows) program (most of the code is actually debris to get a working java program going):

import com.sun.jna.*;
import java.lang.reflect.Field;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Main {

static interface Kernel32 extends Library {

    public static Kernel32 INSTANCE = (Kernel32) Native.loadLibrary("kernel32", Kernel32.class);

    public int GetProcessId(Long hProcess);
}

public static void main(String[] args) {
    try {
        Process p;

        if (Platform.isWindows())
            p = Runtime.getRuntime().exec("cmd /C ping msn.de");
        else if (Platform.isLinux())
            p = Runtime.getRuntime().exec("cmd /C ping msn.de");

        System.out.println("The PID: " + getPid(p));

        int x = p.waitFor();
        System.out.println("Exit with exitcode: " + x);

    } catch (Exception ex) {
        Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
    }
}

public static int getPid(Process p) {
    Field f;

    if (Platform.isWindows()) {
        try {
            f = p.getClass().getDeclaredField("handle");
            f.setAccessible(true);
            int pid = Kernel32.INSTANCE.GetProcessId((Long) f.get(p));
            return pid;
        } catch (Exception ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
    } else if (Platform.isLinux()) {
        try {
            f = p.getClass().getDeclaredField("pid");
            f.setAccessible(true);
            int pid = (Integer) f.get(p);
            return pid;
        } catch (Exception ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
    else{}
    return 0;
}
}

Hope this helps, ;)...

Best Answer

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Java tool/method to force-kill a child process

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