Re: CreateFile performance

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Comments inline:
<r_konjeti@xxxxxxxxxxxx> wrote in message
news:1163082648.727755.307100@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
If many applications are calling driver, each application process
context need a separate handle or duplicate handle for CreateFile(). Is
it same to have a duplicate handle from other process in a given
application process. Or will it make a difference if we call
CreateFile() for each process context.

You want a handle for each process for security reasons. Otherwise an
unauthorized application can try to use you driver as an attack vector.

Will the driver unload if there is handle pending at the user mode for
a device. If the device is removed and handle not closed yet, will it
cause problems? If I implement this scheme, I want to close these file
handle lazy way.

The driver will not unload if there is a reference to it which a handle
owned by a process certainly is a reference so it will not be unloaded.


--
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
http://www.windrvr.com
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