IRP MJ PNP FILTER DRIVER DETAILS:
|File Size:||32.5 MB|
|Supported systems:||Windows XP/Vista/7/8/10, MacOS 10/X|
|Price:||Free* (*Free Registration Required)|
IRP MJ PNP FILTER DRIVER
The following list summarizes the situations in which you can safely acquire a pointer to the PDO at the bottom of a PnP device stack: Device object in a PnP A device object irp mj pnp filter is in a PnP device irp mj pnp filter learns about the stack's PDO when the AddDevice routine for the device is called. Device object in a non-PnP stack, not at bottom of stack For a device object that is not at the bottom of a non-PnP stack, a driver can send a TargetDeviceRelation query to obtain a pointer to the PDO at the bottom of the corresponding PnP device stack.
File object for the device Given a file object for the device, a driver can call IoGetRelatedDeviceObject to get the device irp mj pnp filter and then follow the instructions in the preceding list item. Handle to the device object Given a handle to the device object, a driver can call ObReferenceObjectByHandle to get the file object for the device and then follow the instructions in the preceding list item. Initialize IoStatus. Requirements Header Wdm. Yes No. Any additional feedback? Skip Submit. Send feedback about This product This page. Similar irp mj pnp filter. Upload Log in. My presentations Profile Feedback Log out.
If not, the file system typically locks the volume to prevent future create requests from succeeding.
If a mounted irp mj pnp filter system does not support a query-remove request, the PnP Manager fails the query-remove request for the device. If a file system is mounted on the device, the PnP Manager sends this IRP to the file system and to any file system filters.
The file system should immediately pass this IRP to the storage driver for the device, setting a completion routine in which the file system then dismounts the volume. In accordance with another aspect of the present invention, the filter manager provides efficient context support to store context data e. To this end, the present invention provides context support, via a set of APIs that return context to an entity, and thus simplifies the association of a per-filter context with that entity. The present invention also provides notification support for instances, via a set of callbacks that setup notification for an instance. The types of entities include instances, volumes a local disk volume, or a remote network sharestreams for file systems that support multiple streams per filestream handles per-file objectsand files e.
With respect to instances, as described above, when a filter attaches to a volume, an instance is created, and, as also described above, there may be more than one instance of a given filter for a given volume, e. Each instance can have a context associated, for example to point to a private log for that instance. A volume context can be shared among filter instances. To associate a context with an object, the filter calls FltAllocateContext specifying the type of context stream handle, stream, file, instance or volumethe size of context and whether the context should be allocated from paged or non-paged pool irp mj pnp filter.
As represented in FIG.
Re: IRP Minor function value is wrong some times IRP_- MJ_PNP
Irp mj pnp filter node in the tree represents a filter instance that has an associated context for this stream. Although not separately shown, irp mj pnp filter may be parallel trees, one for paged-pool memory and one for non-paged pool memory, as specified by the filter instance for different types of access that may be needed. For a given stream handle, each node in the tree is accessed by keys, including the file object as one key and the instance as another. Note that for streams, the file object key is NULL. In part the traversal is fast because there are not generally that many filter instances in a given configuration. The context is a PVOID, and the system will treat it as completely opaque, so a filter can use it to store a flags field, a counter, a pointer, or anything else it needs. Notification cleanup callbacks for instances are provided to properly synchronize instance teardown as new operations may be coming to the volume, and include InstanceQueryTeardown, InstanceTeardownStart and InstanceTeardownComplete.
A filter that provides a context structure for some entity will have its corresponding ContextCleanupCallback called.
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In other words, to avoid leaking memory pool, a filter does not need to keep track of which contexts it has allocated, as the system will take care of when cleanup should occur. When a context should be freed, the system calls the filter's ContextCleanupCallback.
During this callback, the filter is responsible to uninitialize the contents of the context and upon return the system will free the memory allocated by the filter's earlier FltAllocateContext call. Cleanups are assumed to succeed; therefore there need not be a return value.
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The system also guarantees that the context cleanups routines will be called at an IRQL low enough that pool frees can be done safely. An instance context gets cleaned up when the filter is detached from the volume.
A volume context gets cleaned up after the volume is dismounted, and after all files, streams, and stream handles for the volume are cleaned up. Due to memory manager, cache manager, and file system implementation details, the volume context may not be cleaned up for a relatively long time after the volume is dismounted. A file context gets cleaned up when the file system frees the memory associated with the file, which in a multiple-stream file system, will be after the last stream handle for the last stream for that irp mj pnp filter is freed. Note that because the operating system's memory manager and cache manager may still have references to one or more streams in the file, the file context may not be cleaned up for a relatively long time after the last user handle to the stream is closed. Similarly, a stream context gets cleaned up irp mj pnp filter the file system frees the memory associated with the stream, which will be after the last stream handle for that stream is freed.
Again, because the operating system's memory manager and cache manager may still have references to one or more streams in the file, the stream context may not be cleaned up for a relatively long time after the last user handle to the stream is closed. Routine Description:. IoFreeIrp pIrp.
NB: the various Minor functions of the PlugPlay system will not irp mj pnp filter a file system is mounted on the device, the PnP Manager sends this IRP to the file system and to any file system filters. The file system should.
IRP_MN_QUERY_DEVICE_RELATIONS - Windows drivers Microsoft Docs
Windows-driver-samples/serial/serenum/pnp.c. Attach our filter driver to the device stack. Our filter will send IRPs to the top of the stack and use the PDO.