IOCTL_DISK_GET_DRIVE_GEOMETRY in mountmgr.sys

[Michael Ost]

Hi,

The ioctl handler for IOCTL_DISK_GET_DRIVE_GEOMETRY on \\\\.\\c: in 
mountmgr.sys doesn't work. The call returns incorrect values that change 
at random intervals.

Since the ioctl is defined as METHOD_BUFFERED I think it should be 
putting DRIVE_GEOMETRY data in IRP->AssociatedIrp.SystemBuffer. Instead 
the handler puts the data in IRP->MdlAddress.StartVa. Then process_ioctl 
in ntoskrnl.exe wipes out the output data with the random stuff in the 
allocated SystemBuffer.

I am out of my depth with windows driver handling code, but a web search 
(http://www.cmkrnl.com/arc-ioctlbuf.html) says that SystemBuffer should 
be where the data is put. Indeed, when I change to SystemBuffer the user 
call to DeviceIoControl gets the right values back.

Am I on the right track?

Thanks, Michael Ost

PS: here's a proposed patch...

--- wine-1.1.7/dlls/mountmgr.sys/device.c.ORIG  2009-03-23 
14:04:30.000000000 -0700
+++ wine-1.1.7/dlls/mountmgr.sys/device.c       2009-03-25 
17:06:24.000000000 -0700
@@ -607,7 +607,7 @@
          info.TracksPerCylinder = 255;
          info.SectorsPerTrack = 63;
          info.BytesPerSector = 512;
-        memcpy( irp->MdlAddress->StartVa, &info, len );
+        memcpy( irp->AssociatedIrp.SystemBuffer, &info, len );
          irp->IoStatus.Information = len;
          irp->IoStatus.u.Status = STATUS_SUCCESS;
          break;