File operations on a Windows Driver (character device)

Alessio Faina
Thu May 21 11:14:00 GMT 2015's really a little world :)

I've got the kernelspace part on github ( ).
It consists of sys (the kernel module), testExe (loads/unloads on the
fly the module
in the kernel) and secondExe that just interact with the first
executable and the kernel
module if it is loaded. With the buildAll.bat if the WDK7.1 is
present, all the applications
are builded automatically.
There is a Cyg.c that represent my effort to connect to the module,
sending an ioctl and doing
an mmap.

I think that, even if it's a semplification of the program I'm
porting, this little project
is very close to what I'm trying to do with the main project.

As I read somewhere else, cygwin doesn't support custom ioctl on
custom modules, have I
understood well? This may explain why I'm never able to send any ioctl
to my module.

For the mmap part, well, I've tried to follow with gdb what Cygwin is
doing but II must admit
that at some point I just lose track of what it's doing.

If it's too messy, I can polish the code a little bit; consider that
it's the environment where I'm
always doing tests so rarely I have the time to clean the code...


2015-05-20 3:19 GMT+02:00 Mark Geisert <>:
> Alessio Faina writes:
>> Well.....I wrote and answered myself the question you pointed out that
>> is residing on stackoverflow....
> Oh, small world :)
>> It was my first option I thought of to pass the pointer to the virtual
>> address to the userland application but
>> I've been asked to mantain the architecture using open(), ioctl(),
>> mmap() etc.... so I don't know, it's a kind of
>> jolly to be played in case I won't be able to use the posix
>> architecture....but reading on forums/mailing lists...
>> I think I will be forced to use the kind of implementation I've
>> described in the SO question.
>> It seems that no-one ever have got the need to do something like I'm
>> trying to do.
>> 2015-05-19 9:52 GMT+02:00 Mark Geisert <XXXX <at> XXXXXX.XXX>:
>> > Does
>> >
>> > help to answer your question?  If it does, you'll still have to decide
>> > whether to translate the Windows calls there into Cygwin calls or instead
>> > just localize the Windows calls in one user-level module and leave
>> > everything else to Cygwin.
> Cygwin is entirely and intentionally in user space.  Most of its users don't
> even need programming access to Windows user space, let alone kernel space.
>  So yes, you're likely to be forging a new path.
> If you get it working with toy Windows test programs, we *might* be able to
> tell you how to convert it to Cygwin, if it's possible.  But the actual
> figuring it out for Windows is outside the scope of what Cygwin is intended
> to provide.
> ..mark
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