Re: gdb: detection and/or fork+gethostbyname crash workaround?

[Daniel Jacobowitz <dmj+ at andrew dot cmu dot edu>]

On Tue, Jul 24, 2001 at 02:22:48PM -0400, Glenn F. Maynard wrote:
> On Tue, Jul 24, 2001 at 08:52:19AM -0700, Kevin Buettner wrote:
> > If it's one which uses ptrace(), the kernel usually prohibits two
> > processes from invoking ptrace() on the same inferior.  So one
> > strategy might be to have the program in question cause ptrace to be
> > invoked on itself.  I don't think the process will be able to do this
> > itself; I think it's likely that it would have to fork and let the
> > child attempt this.  The return status from wait() or waitpid() could
> > indicate whether the attempt to invoke ptrace() was successful or not.
> 
> That's what I tried (x86 Linux); a process can't ptrace itself.  I could
> fork a process to test this, I suppose; I'll try that.  (Wouldn't it
> be the return status from ptrace(), though?  I assume it'd return something
> like EPERM if a process is already being debugged.)

Try ptrace( PTRACE_TRACEME, ...) ?


-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer