How to find the child processes associated with a PID?

Question

Hello everyone,

I'm launching a cmd line script from a c# application with:
cmd /c randomscript.cmd

I save the PID so i can later kill it but, since the "randomscript.cmd" launches other applications, the application doesn't actually stop when i kill it (because the other applications launched by my randomscript.cmd).

Basically, i've found that i should look for all the childs associated with a given PID so i can then kill them.

Does anybody know how i can do this?

I have an example for getting the parent id for a given child but that's exactly the opposite from what i want to achieve: i want the CHILD for the given Parent!

Thanks in advance!
Luís Silva

Answer 1

Basically, i'm looking for something that does the exact same as:
C:\Documents and Settings\Administrator>taskkill /PID 4316 /T /F
SUCCESS: The process with PID 2124 (child process of PID 4316) has been terminated.
SUCCESS: The process with PID 4316 (child process of PID 792) has been terminated.

C:\Documents and Settings\Administrator>

Thanks!

Answer 2

For whoever might care, the solution is here:

        /*
         * kill a job by its PID
         * and all associated childs
         */
        public bool killProcess(int pid)
        {
            bool didIkillAnybody = false;
            try
            {
                Process[] procs = Process.GetProcesses();
                for (int i = 0; i < procs.Length; i++)
                {
                    if (GetParentProcess(procs.Id) == pid)
                        /*
                         * the good thing about this
                         * is that we will also kill
                         * any child for the child process! ;o)
                         * will this be a memory hog?
                         */
                        if (killProcess(procs.Id) == true)
                            didIkillAnybody = true;
                }
                try
                {
                    /*
                     * basically, the fact that we killed all the child
                     * could have DEVASTED the parent which, sadly,
                     * could have commited suicide!
                     */
                    Process myProc = Process.GetProcessById(pid);
                    myProc.Kill();
                    return true;
                }
                catch { }
            }
            catch (Exception ex)
            {
                try
                {
                    Logger log = new Logger();
                    log.Write("Exception caught at JobExecution.killProcess()", ex.Message, System.Diagnostics.EventLogEntryType.Warning, false);
                }
                catch { }
            }
            return didIkillAnybody;
        }

        /*
         * get parent process for a given PID
         */
        private int GetParentProcess(int Id)
        {
            int parentPid = 0;
            using (ManagementObject mo = new ManagementObject("win32_process.handle='" + Id.ToString() + "'"))
            {
                mo.Get();
                parentPid = Convert.ToInt32(mo["ParentProcessId"]);
            }
            return parentPid;
        }


This other thread i posted really helped me:
http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=2946225&SiteID=1&mode=1

Answer 3

This may be a very late post, but I had a question regarding the usage of ManagementObject.

Firstly, Thanks a lot for posting your solution. This has been very useful for me as I had a very similar situation where I launch a script and the script launches other processes that I need to kill. The solution above seems to work fine most of the time. At some instances though, mo.Get() results in the exception below:

Message:Not found
Stacktrace:   at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode)
   at System.Management.ManagementObject.Get()

I have looked around but have not found any reason why this happens. After this exception is thrown, the child process gets orphaned and I end up killing it manually.

Have you faced this issue? Any input would be very useful.

Thanks

Answer 4

I found this code to work for me:

private void KillProcessAndChildren(int pid)
{
 ManagementObjectSearcher searcher = new ManagementObjectSearcher("Select * From Win32_Process Where ParentProcessID=" + pid);
 ManagementObjectCollection moc = searcher.Get();
 foreach (ManagementObject mo in moc)
 {
  KillProcessAndChildren(Convert.ToInt32(mo["ProcessID"]));
 }
 try
 {
  Process proc = Process.GetProcessById(pid);
  proc.Kill();
 }
 catch (ArgumentException)
 { /* process already exited */ }
}

Answer 5

Excelent method! @RonaldDev

Answer 6

public void StopProcess(Process p)
        {
            if (p != null)
            {
                Process KillerP = new Process();
                KillerP.StartInfo.FileName = "taskkill.exe";
                KillerP.StartInfo.Arguments = "/PID " + p.Id + " /T /F";
                KillerP.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
                KillerP.Start();
                KillerP.WaitForExit();
            }
        }

Answer 7

Don't get put off by the name of the routine Familicide: a slight modification of RonaldDev's KillProcessAndChildren.

Regards, Paul

private void Familicide(int pid)
{
// kill a process tree (family)
// this code requires the reference for System.Managemnt.dll

// First a list of children is build in pids. Then the process with pid is killed and Familicide is called for each child.
// If a straight recursive approach is used, than it's possible to miss-out on children created between the call to
// Familicide and requesting the list of children through the searcher.

SortedSet<Int32> pids = new SortedSet<Int32>();
System.Management.ManagementObjectSearcher searcher = new System.Management.ManagementObjectSearcher("Select * From Win32_Process Where ParentProcessID=" + pid);
System.Management.ManagementObjectCollection moc = searcher.Get;
foreach (System.Management.ManagementObject mo in moc) {
try {
pids.Add(Convert.ToInt32(mo.Item("ProcessID")));
} catch {
// process already exited, so get Item("ProcessID") will raise an error
}
}

try {
Process aProcess = Process.GetProcessById(pid);
aProcess.Kill();
} catch (ArgumentException ex) {
// process already exited
}
foreach (Int32 aChildPid in pids) {
Familicide(aChildPid);
}

}

---

PE