iowork.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/*
 * PROJECT:         ReactOS Kernel
 * LICENSE:         GPL - See COPYING in the top level directory
 * FILE:            ntoskrnl/io/iowork.c
 * PURPOSE:         I/O Wrappers for the Executive Work Item Functions
 * PROGRAMMERS:     Alex Ionescu ([e-mail])
 *                  Robert Dickenson ([e-mail])
 */

/* INCLUDES ******************************************************************/

#include <ntoskrnl.h>
#define NDEBUG
#include <internal/debug.h>

/* PRIVATE FUNCTIONS *********************************************************/

VOID
NTAPI
IopWorkItemCallback(IN PVOID Parameter)
{
    PIO_WORKITEM IoWorkItem = (PIO_WORKITEM)Parameter;
    PDEVICE_OBJECT DeviceObject = IoWorkItem->DeviceObject;
    PAGED_CODE();

    /* Call the work routine */
    IoWorkItem->WorkerRoutine(DeviceObject, IoWorkItem->Context);

    /* Dereferenece the device object */
    ObDereferenceObject(DeviceObject);
}

/* PUBLIC FUNCTIONS **********************************************************/

/*
 * @implemented
 */
VOID
NTAPI
IoQueueWorkItem(IN PIO_WORKITEM IoWorkItem,
                IN PIO_WORKITEM_ROUTINE WorkerRoutine,
                IN WORK_QUEUE_TYPE QueueType,
                IN PVOID Context)
{
    /* Make sure we're called at DISPATCH or lower */
    ASSERT_IRQL_LESS_OR_EQUAL(DISPATCH_LEVEL);

    /* Reference the device object */
    ObReferenceObject(IoWorkItem->DeviceObject);

    /* Setup the work item */
    IoWorkItem->WorkerRoutine = WorkerRoutine;
    IoWorkItem->Context = Context;

    /* Queue the work item */
    ExQueueWorkItem(&IoWorkItem->Item, QueueType);
}

/*
 * @implemented
 */
VOID
NTAPI
IoFreeWorkItem(IN PIO_WORKITEM IoWorkItem)
{
    /* Free the work item */
    ExFreePool(IoWorkItem);
}

/*
 * @implemented
 */
PIO_WORKITEM
NTAPI
IoAllocateWorkItem(IN PDEVICE_OBJECT DeviceObject)
{
    PIO_WORKITEM IoWorkItem;

    /* Allocate the work item */
    IoWorkItem = ExAllocatePoolWithTag(NonPagedPool,
                                       sizeof(IO_WORKITEM),
                                       TAG_IOWI);
    if (!IoWorkItem) return NULL;

    /* Initialize it */
    IoWorkItem->DeviceObject = DeviceObject;
    ExInitializeWorkItem(&IoWorkItem->Item, IopWorkItemCallback, IoWorkItem);

    /* Return it */
    return IoWorkItem;
}

/* EOF */