WinDBG can do some local debugging using 'windbg -kl'. In that case,
WinDBG tries to directly use NtSystemDebugControl. If this function
returns an error, WinDBG extracts a driver from its resources.
WinDBG will send IOCTLs to this driver, and this driver will call
KdSystemDebugControl.
However, on livecd (where %SYSTEMROOT% is read-only), WinDBG is unable
to extract the driver from its resources, and can't use the driver to
call KdSystemDebugControl.
As a work-around, allow all control classes in NtSystemDebugControl
in case of livecd.
WinDBG local debugging now also works on livecd (windbg -kl).
- Add SEH probing for user buffer
- Mark some classes as i386 only
- Explicitly return STATUS_NOT_IMPLEMENTED on disabled classes (must use KdSystemDebugControl instead)
- Explicitly return STATUS_NOT_IMPLEMENTED on not implemented classes
- Return STATUS_INVALID_INFO_CLASS on all other classes
Hervé Poussineau