Re: context questions

Hi Bruce,

Thank you very much for clarify this. I was assigned a task to port a filter
driver from XP to PPC 2003. I plan to use hook technics. In XP,
IRP_MJ_CREATE received by filter driver is in the same process context as
CreateFile in application. Therefore, kernel mode driver can directly access
memory in user mode application. But in PPC 2003 the scenario seems to be
different. What happens between a CreateFile call in one process and
Driver_Open in device.exe? Is there process context switch? Does CE map the
device name, used as the first parameter of CreateFile, from the caller
process to device.exe? And why MapPtrToProcess doesn't need to specify a
size?


"Bruce Eitman (eMVP)" <beitmannospam@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> дÈëÏûÏ¢ÐÂÎÅ:%23ojpPQRfFHA.2384@xxxxxxxxxxxxxxxxxxxxxxx
> The driver is always running in device.exe (unless you specifically do a
> LoadLibrary) so the memory is still accessible to you.
>
> Are you having a problem that you need to solve or is this just
> philisophical?
>
> --
> Bruce Eitman (eMVP)
> Senior Engineer
> beitman AT applieddata DOT net
>
> Applied Data Systems
> www.applieddata.net
> An ISO 9001:2000 Registered Company
> Microsoft WEP Gold-level Member
>
>
> "telus" <tobeno1@xxxxxxxxx> wrote in message
> news:qNHwe.100195$9A2.18194@xxxxxxxxxxx
>> Hi,
>>
>> I'm developing a driver for PPC 2003. The driver is loaded in device.exe
>> address space and is located in slot 0. During Driver_Init I allocate a
>> memory and save a pointer in a global variable in the driver. Whenever an
>> application opens the driver, I need to save some information in the
> memory.
>>
>> 1) In Driver_Open call of the driver, I'm in the application context, not
>> device.exe context, right?
>> 2) If 1) is true, how can I access the memory which is allocated in
>> Driver_Init which is in device.exe context? Do I have to add the pointer
>> with a base address of the slot of device.exe and call MapPtrToProcess?
>>
>> TIA
>>
>>
>
>


.

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