Mapped network drives and IoGetDeviceObjectPointer funnies...

NTFSD
1

Hi,

Can anyone explain the following behaviour and how to get around it:

Environment:

OS: W2K SP3
I have a mapped network drive E:
E: is valid and has been accessed before running the following,
Open My Computer and show all volumes
Run the following:

Within my driver I call the following code:

bHardErrorMode = IoSetThreadHardErrorMode( FALSE );

ntstatus = IoGetDeviceObjectPointer( (PUNICODE_STRING) ObjectName,

FILE_READ_ATTRIBUTES,
&fileObject,
&pDeviceObject
);

IoSetThreadHardErrorMode( bHardErrorMode );

ObjectName is set to “\DosDevices\E:”

On return ntstatus is 0xC0000022 (STATUS_ACCESS_DENIED), fileObject is
NULL, pDeviceObject is NULL (This is not the point of concern, but would
be interested in knowing why I am getting a STATUS_ACCESS_DENIED,
anyways…)

However when this all returns and I refresh the “My Computer” view (F5),
E: has the network disconnet icon, but functions as normal.

If I substitute FILE_READ_ATTRIBUTES with FILE_READ_DATA the same
happens.

Any hints as to why this is happening and how I can NOT have this
happen?

Thanks in advance,

John

2

Is your driver routine running in a thread that has the proper access
rights to access the shared resource?

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of John Tobin
Sent: Wednesday, October 09, 2002 12:45 PM
To: File Systems Developers
Subject: [ntfsd] Mapped network drives and IoGetDeviceObjectPointer
funnies…

Hi,

Can anyone explain the following behaviour and how to get around it:

Environment:

OS: W2K SP3
I have a mapped network drive E:
E: is valid and has been accessed before running the following,
Open My Computer and show all volumes
Run the following:

Within my driver I call the following code:

bHardErrorMode = IoSetThreadHardErrorMode( FALSE );

ntstatus = IoGetDeviceObjectPointer( (PUNICODE_STRING) ObjectName,

FILE_READ_ATTRIBUTES,
&fileObject,
&pDeviceObject
);

IoSetThreadHardErrorMode( bHardErrorMode );

ObjectName is set to “\DosDevices\E:”

On return ntstatus is 0xC0000022 (STATUS_ACCESS_DENIED), fileObject is
NULL, pDeviceObject is NULL (This is not the point of concern, but would
be interested in knowing why I am getting a STATUS_ACCESS_DENIED,
anyways…)

However when this all returns and I refresh the “My Computer” view (F5),
E: has the network disconnet icon, but functions as normal.

If I substitute FILE_READ_ATTRIBUTES with FILE_READ_DATA the same
happens.

Any hints as to why this is happening and how I can NOT have this
happen?

Thanks in advance,

John

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3

No,

It is run using the follow:

PsCreateSystemThread( &ThreadHandle, 0l, NULL, NULL,
NULL, TheRoutine, &Ctxt );

Where “TheRoutine” is the function that runs what has been described.

You may be on to something…

John

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Wednesday, October 09, 2002 12:57 PM
To: File Systems Developers
Subject: [ntfsd] RE: Mapped network drives and
IoGetDeviceObjectPointer funnies…

Is your driver routine running in a thread that has the proper access
rights to access the shared resource?

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of John Tobin
Sent: Wednesday, October 09, 2002 12:45 PM
To: File Systems Developers
Subject: [ntfsd] Mapped network drives and IoGetDeviceObjectPointer
funnies…

Hi,

Can anyone explain the following behaviour and how to get around it:

Environment:

OS: W2K SP3
I have a mapped network drive E:
E: is valid and has been accessed before running the following,
Open My Computer and show all volumes
Run the following:

Within my driver I call the following code:

bHardErrorMode = IoSetThreadHardErrorMode( FALSE );

ntstatus = IoGetDeviceObjectPointer( (PUNICODE_STRING) ObjectName,

FILE_READ_ATTRIBUTES,
&fileObject,
&pDeviceObject
);

IoSetThreadHardErrorMode( bHardErrorMode );

ObjectName is set to “\DosDevices\E:”

On return ntstatus is 0xC0000022 (STATUS_ACCESS_DENIED), fileObject is
NULL, pDeviceObject is NULL (This is not the point of
concern, but would
be interested in knowing why I am getting a STATUS_ACCESS_DENIED,
anyways…)

However when this all returns and I refresh the “My Computer”
view (F5),
E: has the network disconnet icon, but functions as normal.

If I substitute FILE_READ_ATTRIBUTES with FILE_READ_DATA the same
happens.

Any hints as to why this is happening and how I can NOT have this
happen?

Thanks in advance,

John

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