Re: [GD-Windows] Call stack

[brian s. <bri...@gm...>]

On Wed, 9 Feb 2005 13:49:44 -0500, Daniel Vogel
<Dan...@ep...> wrote:
> > the stack.  I have plenty of cases in the engine where I
> > capture a call stack for debugging later if something else
> 
> IMO StackWalk64 is mostly useless for this case as you cannot call
> GetThreadContext on a running thread.
> 
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/debug/b
> ase/getthreadcontext.asp
> 
> I assume you're doing this as that's exactly what we did with our proxy
> malloc and it broke with SP2 as well.

When I wrote my callstack walker for my malloc routine, I took the
docs at their word and assumed that calling GetThreadContext from my
current thread wouldn't work.  So I just filled in the relevant bits
of the STACKFRAME structure myself before calling StackWalk.

I haven't tested this code with SP2 yet though.  The best I can
promise is that it *might* not fall over :).

--brian

---- begin code -----

// This function exists because EIP cannot be read directly.
// What this function does is read the return address off the top of
// the stack into EAX, so that the caller can get a valid EIP value in
// their call frame.
__declspec(naked) void LoadCallerEipIntoEax(void)
{
   __asm {
       mov eax, [esp]
       ret
   }
}

   // Init the stack frame with relevant bits of thread context.  We
   // don't call GetThreadContext as it claims to not work for a
   // running thread
   STACKFRAME stackFrame;
   ZeroMemory(&stackFrame, sizeof(stackFrame));

   __asm {
       call LoadCallerEipIntoEax
       mov stackFrame.AddrPC.Offset,    eax
       mov stackFrame.AddrStack.Offset, esp
       mov stackFrame.AddrFrame.Offset, ebp
   };
   stackFrame.AddrPC.Mode    = AddrModeFlat;
   stackFrame.AddrStack.Mode = AddrModeFlat;
   stackFrame.AddrFrame.Mode = AddrModeFlat;

---- end code -----

--brian