Class Filter Driver for DiskDrive

NTFSD
1

I am trying to develop a lower level class filter driver for DiskDrive. I was looking around for ways to achieve this. I have the following questions:

1- Is my assumption correct that a class filter driver is configured as upper or lower filter according to the specification made in INF file?

For example kbfiltr installs as upper filter according to the relevant INF section as follows:

[kbfiltr.HW.AddReg]
HKR,“UpperFilters”,0x00010000,“kbfiltr”

If i change this to:

HKR,“LowerFilters”,0x00010000,“kbfiltr”

then it will install as a lower filter driver for keyboard without requiring any change in the source code for this sample. Is that correct or changes will be required?

2- If change is required then generally for class filters what portions need to be modified?

3- For a bare bone class filter driver for diskdrive i just need to have two functions to begin with:

  • DriverEntry
  • EvtDeviceAdd -----> having a call to WdfDeviceInitSetDeviceType(DeviceInit, FILE_DEVICE_DISK);

Is that correct?

Thanks for all the help.

sarshah.

2

Doesn’t belong to ntfsd, post on NTDEV.

-Deepak

On Tue, Apr 5, 2011 at 1:37 PM, wrote:

> I am trying to develop a lower level class filter driver for DiskDrive. I
> was looking around for ways to achieve this. I have the following questions:
>
> 1- Is my assumption correct that a class filter driver is configured as
> upper or lower filter according to the specification made in INF file?
>
> For example kbfiltr installs as upper filter according to the relevant INF
> section as follows:
>
> [kbfiltr.HW.AddReg]
> HKR,“UpperFilters”,0x00010000,“kbfiltr”
>
> If i change this to:
>
> HKR,“LowerFilters”,0x00010000,“kbfiltr”
>
> then it will install as a lower filter driver for keyboard without
> requiring any change in the source code for this sample. Is that correct or
> changes will be required?
>
> 2- If change is required then generally for class filters what portions
> need to be modified?
>
> 3- For a bare bone class filter driver for diskdrive i just need to have
> two functions to begin with:
>
> - DriverEntry
> - EvtDeviceAdd -----> having a call to
> WdfDeviceInitSetDeviceType(DeviceInit, FILE_DEVICE_DISK);
>
> Is that correct?
>
> Thanks for all the help.
>
> sarshah.
>
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3

Thanks. Did not realize it earlier :). I have posted it on NTDEV.

sarshah

4

You list is probably sufficient, but not particularly useful.

Mark Roddy

On Tue, Apr 5, 2011 at 10:20 AM, wrote:
> Thanks. Did not realize it earlier :). I have posted it on NTDEV.
>
> sarshah
>
> —
> NTFSD is sponsored by OSR
>
> For our schedule of debugging and file system seminars visit:
> http://www.osr.com/seminars
>
> To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer
>