KsCreateDefaultAllocatorEx function (ks.h)

Article
03/15/2022

Creates a default allocator that uses the specified memory pool and associates the IoGetCurrentIrpStackLocation(pIrp)->FileObject with this allocator using an internal dispatch table (KSDISPATCH_TABLE).

Syntax

KSDDKAPI NTSTATUS KsCreateDefaultAllocatorEx(
  [in]           PIRP                     Irp,
  [in, optional] PVOID                    InitializeContext,
  [in, optional] PFNKSDEFAULTALLOCATE     DefaultAllocate,
  [in, optional] PFNKSDEFAULTFREE         DefaultFree,
  [in, optional] PFNKSINITIALIZEALLOCATOR InitializeAllocator,
  [in, optional] PFNKSDELETEALLOCATOR     DeleteAllocator
);

Parameters

[in] Irp

Contains the IRP with the allocator create request being handled.

[in, optional] InitializeContext

Optionally contains a context to use with an external allocator. This is only used as the initialization context to the optional InitializeAllocator callback when creating an allocator context. The parameter is not otherwise used. If an external allocator is not provided, this parameter must be set to NULL.

[in, optional] DefaultAllocate

Optionally contains an external allocate function that is used in place of the default pool allocation. If this is NULL, default allocation is used.

[in, optional] DefaultFree

Optionally contains an external free function that is used in place of the default pool allocation. If an external allocator is not provided, this parameter must be set to NULL.

[in, optional] InitializeAllocator

Optionally contains an external allocator initialization function to which the InitializeContext parameter is passed. This function is expected to return an allocator context based on the allocator framing. If an external allocator is not provided, this parameter must be set to NULL.

[in, optional] DeleteAllocator

Optionally contains an external allocator delete function that is used for external allocators. If an external allocator is not provided, this parameter must be set to NULL.

Return value

Returns STATUS_SUCCESS, else an error on default allocator creation failure. Does not complete the IRP or set the status in the IRP.

Remarks

Before calling this routine, the KSCREATE_ITEM_IRP_STORAGE(Irp) macro should return a pointer to the KSOBJECT_CREATE_ITEM structure that is the create item for this allocator. KsCreateDefaultAllocatorEx sets FsContext to point to the return value of this macro. As such, FsContext can later be used for security descriptor queries or changes.

You can find KSCREATE_ITEM_IRP_STORAGE(Irp) and related macros in ks.h.

Requirements

Requirement	Value
Target Platform	Universal
Header	ks.h (include Ks.h)
Library	Ks.lib

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