Blocking System files in file system driver

NTFSD
1

Hi All,

I am developing a file system filter driver on Windows 2000, which needs to
block the read operation of any file and communicate to the application that
is running in usermode. The blocking of files gets stated only after the
user mode application sends an IOCTL saying to block, and the application
starts a thread to get the data from the driver about the files

When I am doing this if I am blocking and system files (like .sys and some
.dlls) the system is not responding and getting hanged. What I think is even
if I block some system files my application should and my driver
communication should be effected, but the behaviour is not like this. What
could be the problem, is there any way to fix this.

Any information is helpful.

Thanks,
Kedar.

2

There are just too many things that may cause what you see. For example,
imagine the scenario:

  1. Read IRP comes, you signal the app and block the thread waiting for
    response.
  2. App handles driver’s request and in that process one of the system
    dll’s jumps to a paged out code.
  3. This triggers paging read IRP that goes to your driver and “goto step
    1”

Depending on how your KM <-> UM communication is set up that could be a
hung that you see.

-----Original Message-----
From: Kedar [mailto:xxxxx@hotmail.com]
Sent: Thursday, May 27, 2004 11:39 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] Blocking System files in file system driver

Hi All,

I am developing a file system filter driver on Windows 2000, which needs
to
block the read operation of any file and communicate to the application
that
is running in usermode. The blocking of files gets stated only after the
user mode application sends an IOCTL saying to block, and the
application
starts a thread to get the data from the driver about the files

When I am doing this if I am blocking and system files (like .sys and
some
.dlls) the system is not responding and getting hanged. What I think is
even
if I block some system files my application should and my driver
communication should be effected, but the behaviour is not like this.
What
could be the problem, is there any way to fix this.

Any information is helpful.

Thanks,
Kedar.

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as:
xxxxx@borland.com
To unsubscribe send a blank email to xxxxx@lists.osr.com