debugging longman dictionary
laurent.pinchart at skynet.be
Mon Mar 25 14:58:05 CST 2002
> > > what I'd do is:
> > > - simulate (as for DR?) the IDTR read/write (memory/instr)
> > > - provide our own interrupt table
> > > - then hook the signal catches to this table (dlls/ntdll/
> > > - in your case, especially the divide by 0 signal to entry 1 of this
> > > table
> > >
> > > however, I don't think this is the best way to go. It will add lots of
> > > code to Wine (mainly i386 virtualization), and let programs modify
> > > things
> > > they shouldn't normally need to touch.
> > Even if you did this, it probably wouldn't help much, as the
> > interrupt routine is supposed to be executed in ring 0 (which
> > presumably is the very *reason* the program does this nonsense).
> > So you'll fail immediately afterwards due to privilege
> > violations as the app does whatever it wants to do in ring 0 ...
> > Of course, you could add virtualization for all the ring 0 stuff,
> > but this is quite open-ended :-(
> The copy-protection support in WineX does some of this stuff. If the stuff
> the application in question does is just another copy protection (sounds
> like it), then the additional ring 0 stuff you need to virtualize is
> probably just access to the debug registers.
The application tries to execute some (trivial) code in ring 0 mode by
modifying the IDTR when run in win95/win98 mode. The problem doesn't occur in
winNT mode, so I don't think we should implement a complete ring 0
In winNT mode the debugger detection is done by calling int 0x01 and checking
a 'side effect' (probably an exception handler effect). I'll check if the
detection fails or not.
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