From: "Berger, Daniel" <Daniel.Berger@...>
Date: 2005-10-20T00:45:28+09:00
Subject: Re: Killing Threads & Processes on Windows

> -----Original Message-----
> From: Dave Burt [mailto:dave@burt.id.au] 
> Sent: Wednesday, October 19, 2005 8:07 AM
> To: ruby-talk ML
> Subject: Re: Killing Threads & Processes on Windows
> 
> 
> I accidentally sent:
> > nobu nakada wrote:
> >> I know about TerminateProcess(), but think it is 
> considered critical 
> >> for general purpose, like as SIGKILL.
> >
> > You're probably right, it is severe, but rb_waitpid 
> shouldn't return 
> > with
> > the process still running, should it?
> 
> .... or just hang without closing the process?
> 
> Would a call to TerminateProcess() go in wait() in win32/win32.c?
> 
> Cheers,
> Dave 

The win32/process package uses a CreateRemoteThread() + ExitProcess()
approach (except for signal 9, which then uses TerminateProcess).  This
was recommended as a safer way to kill Windows processes (by Jeremy
Richter, among others).

Here's the C code (with a small bit elided out):

// hProcess is a HANDLE acquired by OpenProcess() earlier
if(hProcess){
   hThread = CreateRemoteThread(
      hProcess,
      NULL,
      0,
      (LPTHREAD_START_ROUTINE)(
         GetProcAddress(
            GetModuleHandle("KERNEL32.DLL"), "ExitProcess"
         )
      ),
      0,
      0,
      &dwThreadId
   );

   if(hThread){
      WaitForSingleObject(hThread, dwTimeout);
      CloseHandle(hProcess);
      ...
   }
   else{
      CloseHandle(hProcess);
      // Raise an error
   }  
 }