More newbie questions! Ok, I added instance context data to my driver, and I can set it just fine in my EvtDeviceAdd and EvtDevicePrepareHardware… BUT… how on Earth do I access instance data from the IOCTL, since I don’t have a driver handle??!
I’m sure it’s something simple and my Google-Fu is weak today.
…ed…
xxxxx@woolyloach.com wrote:
More newbie questions! Ok, I added instance context data to my driver, and I can set it just fine in my EvtDeviceAdd and EvtDevicePrepareHardware… BUT… how on Earth do I access instance data from the IOCTL, since I don’t have a driver handle??!
Your context data is not part of the driver object, it’s part of the
device object.
I’m sure it’s something simple and my Google-Fu is weak today.
Must be, since every single KMDF sample does this. One of the cool
things about KMDF is that there is a complete set of “get this from
that” operations. Given a WDFQUEUE, you can get the WDFDEVICE. From
there, you can get the device context:
VOID
MyEvtIoDeviceControl(
IN WDFQUEUE Queue, …
)
{
…
WDFDEVICE hDevice = WdfIoQueueGetDevice(Queue);
PMY_CONTEXT pContext = MyDeviceGetContext(hDevice);
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
You should have very little context information hanging off of a WDFDRIVER. You want most of your information hanging off of a context of a WDFDEVICE. To get to that context, you need can call WdfIoQueueGetDevice to get the WDFDEVICE in your io event handler.
d
-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@woolyloach.com
Sent: Wednesday, October 13, 2010 10:38 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Getting driver context info when in IOCTL handler?
More newbie questions! Ok, I added instance context data to my driver, and I can set it just fine in my EvtDeviceAdd and EvtDevicePrepareHardware… BUT… how on Earth do I access instance data from the IOCTL, since I don’t have a driver handle??!
I’m sure it’s something simple and my Google-Fu is weak today.
…ed…
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@Tim - yes, it’s the device, I mis-typed. I guess I shouldn’t come to work with the flu… :-/
@doron - yep, absolutely.
Ok, off to implement this, then I’m going home before I look like even more of an idiot! Thanks for the info!
…ed…
But as someone who often does have a need for global context in a driver [for various test tools needing global control structures, etc.], I’ll just point out that there is WdfGetDriver(), thereby covering even that base 
-----Original Message-----
Sent: Wednesday, October 13, 2010 10:42 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] Getting driver context info when in IOCTL handler?
You should have very little context information hanging off of a WDFDRIVER. You want most of your information hanging off of a context of a WDFDEVICE. To get to that context, you need can call WdfIoQueueGetDevice to get the WDFDEVICE in your io event handler.
d
-----Original Message-----
Sent: Wednesday, October 13, 2010 10:38 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Getting driver context info when in IOCTL handler?
More newbie questions! Ok, I added instance context data to my driver, and I can set it just fine in my EvtDeviceAdd and EvtDevicePrepareHardware… BUT… how on Earth do I access instance data from the IOCTL, since I don’t have a driver handle??!
I’m sure it’s something simple and my Google-Fu is weak today.
…ed…