A real fork() on NT

[Corinna Vinschen]

On Wed, Jan 30, 2002 at 11:03:00AM +0000, Christopher January wrote:
> > When looking at XP's CreateProcessW (or rather, CreateProcessInternalW) I
> > noticed something strange about the way it creates a process.  It seems
> > that NT is sort of capable of a fork() command.  The function
> > NtCreateProcess appears to create a "blank" process, into which you can put
> > anything you want.  After NtCreateProcess, kernel32 maps the EXE into that
> > new process's memory space, creates a thread, and finally calls
> > NtResumeThread to start its execution.
> >
> > If this long, nasty, scattered function could be reverse engineered, it
> > should be possible to create a true fork() for NT, instead of doing the
> > normal cygwin "hack" method.
> Coincidentally, I was looking into a similar thing myself. Windows NT has a 
> POSIX subsystem that's capable of doing fork()'s so it is obviously possible. 
> Have you any ideas of the arguments passed to the function or what it returns?

That isn't really new.  I'd like to point you to the example 6.1,
"Forking a Win32 Process" on p. 161ff of Gary Nebbett's excellent
book "Windows NT/2000 Native API Reference", published by MTP,
ISBN 1-57870-199-6, which also describes the problem with kernel32.dll
initialization of the child process.

Corinna

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Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin@cygwin.com
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