irp.c

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        StackPtr++;
    } while (Irp->CurrentLocation <= (Irp->StackCount + 1));

    /* Check if the IRP is an associated IRP */
    if (Irp->Flags & IRP_ASSOCIATED_IRP)
    {
        /* Get the master IRP and count */
        MasterIrp = Irp->AssociatedIrp.MasterIrp;
        MasterCount = InterlockedDecrement(&MasterIrp->AssociatedIrp.IrpCount);

        /* Free the MDLs */
        for (Mdl = Irp->MdlAddress; Mdl; Mdl = NextMdl)
        {
            /* Go to the next one */
            NextMdl = Mdl->Next;
            IoFreeMdl(Mdl);
        }

        /* Free the IRP itself */
        IoFreeIrp(Irp);

        /* Complete the Master IRP */
        if (!MasterCount) IofCompleteRequest(MasterIrp, PriorityBoost);
        return;
    }

    /* We don't support this yet */
    ASSERT(Irp->IoStatus.Status != STATUS_REPARSE);

    /* Check if we have an auxiliary buffer */
    if (Irp->Tail.Overlay.AuxiliaryBuffer)
    {
        /* Free it */
        ExFreePool(Irp->Tail.Overlay.AuxiliaryBuffer);
        Irp->Tail.Overlay.AuxiliaryBuffer = NULL;
    }

    /* Check if this is a Paging I/O or Close Operation */
    if (Irp->Flags & (IRP_PAGING_IO | IRP_CLOSE_OPERATION))
    {
        /* Handle a Close Operation or Sync Paging I/O */
        if (Irp->Flags & (IRP_SYNCHRONOUS_PAGING_IO | IRP_CLOSE_OPERATION))
        {
            /* Set the I/O Status and Signal the Event */
            Flags = Irp->Flags & (IRP_SYNCHRONOUS_PAGING_IO | IRP_PAGING_IO);
            *Irp->UserIosb = Irp->IoStatus;
            KeSetEvent(Irp->UserEvent, PriorityBoost, FALSE);

            /* Free the IRP for a Paging I/O Only, Close is handled by us */
            if (Flags) IoFreeIrp(Irp);
        }
        else
        {
#if 0
            /* Page 166 */
            KeInitializeApc(&Irp->Tail.Apc
                            &Irp->Tail.Overlay.Thread->Tcb,
                            Irp->ApcEnvironment,
                            IopCompletePageWrite,
                            NULL,
                            NULL,
                            KernelMode,
                            NULL);
            KeInsertQueueApc(&Irp->Tail.Apc,
                             NULL,
                             NULL,
                             PriorityBoost);
#else
            /* Not implemented yet. */
            DPRINT1("Not supported!\n");
            while (TRUE);
#endif
        }

        /* Get out of here */
        return;
    }

    /* Unlock MDL Pages, page 167. */
    Mdl = Irp->MdlAddress;
    while (Mdl)
    {
        MmUnlockPages(Mdl);
        Mdl = Mdl->Next;
    }

    /* Check if we should exit because of a Deferred I/O (page 168) */
    if ((Irp->Flags & IRP_DEFER_IO_COMPLETION) && !(Irp->PendingReturned))
    {
        /*
         * Return without queuing the completion APC, since the caller will
         * take care of doing its own optimized completion at PASSIVE_LEVEL.
         */
        return;
    }

    /* Get the thread and file object */
    Thread = Irp->Tail.Overlay.Thread;
    FileObject = Irp->Tail.Overlay.OriginalFileObject;

    /* Make sure the IRP isn't canceled */
    if (!Irp->Cancel)
    {
        /* Initialize the APC */
        KeInitializeApc(&Irp->Tail.Apc,
                        &Thread->Tcb,
                        Irp->ApcEnvironment,
                        IopCompleteRequest,
                        NULL,
                        NULL,
                        KernelMode,
                        NULL);

        /* Queue it */
        KeInsertQueueApc(&Irp->Tail.Apc,
                         FileObject,
                         NULL, /* This is used for REPARSE stuff */
                         PriorityBoost);
    }
    else
    {
        /* The IRP just got canceled... does a thread still own it? */
        Thread = Irp->Tail.Overlay.Thread;
        if (Thread)
        {
            /* Yes! There is still hope! Initialize the APC */
            KeInitializeApc(&Irp->Tail.Apc,
                            &Thread->Tcb,
                            Irp->ApcEnvironment,
                            IopCompleteRequest,
                            NULL,
                            NULL,
                            KernelMode,
                            NULL);

            /* Queue it */
            KeInsertQueueApc(&Irp->Tail.Apc,
                             FileObject,
                             NULL, /* This is used for REPARSE stuff */
                             PriorityBoost);
        }
        else
        {
            /* Nothing left for us to do, kill it */
            ASSERT(Irp->Cancel);
            IopCleanupIrp(Irp, FileObject);
        }
    }
}

/*
 * @unimplemented
 */
BOOLEAN
NTAPI
IoForwardIrpSynchronously(IN PDEVICE_OBJECT DeviceObject,
                          IN PIRP Irp)
{
    UNIMPLEMENTED;
    return FALSE;
}

/*
 * @implemented
 */
VOID
NTAPI
IoFreeIrp(IN PIRP Irp)
{
    PNPAGED_LOOKASIDE_LIST List;
    PP_NPAGED_LOOKASIDE_NUMBER ListType =  LookasideSmallIrpList;
    PKPRCB Prcb;
    IOTRACE(IO_IRP_DEBUG,
            "%s - Freeing IRPs %p\n",
            __FUNCTION__,
            Irp);

    /* Make sure the Thread IRP list is empty and that it OK to free it */
    ASSERT(Irp->Type == IO_TYPE_IRP);
    ASSERT(IsListEmpty(&Irp->ThreadListEntry));
    ASSERT(Irp->CurrentLocation >= Irp->StackCount);

    /* If this was a pool alloc, free it with the pool */
    if (!(Irp->AllocationFlags & IRP_ALLOCATED_FIXED_SIZE))
    {
        /* Free it */
        ExFreePool(Irp);
    }
    else
    {
        /* Check if this was a Big IRP */
        if (Irp->StackCount != 1) ListType = LookasideLargeIrpList;

        /* Get the PRCB */
        Prcb = KeGetCurrentPrcb();

        /* Use the P List */
        List = (PNPAGED_LOOKASIDE_LIST)Prcb->PPLookasideList[ListType].P;
        List->L.TotalFrees++;

        /* Check if the Free was within the Depth or not */
        if (ExQueryDepthSList(&List->L.ListHead) >= List->L.Depth)
        {
            /* Let the balancer know */
            List->L.FreeMisses++;

            /* Use the L List */
            List = (PNPAGED_LOOKASIDE_LIST)Prcb->PPLookasideList[ListType].L;
            List->L.TotalFrees++;

            /* Check if the Free was within the Depth or not */
            if (ExQueryDepthSList(&List->L.ListHead) >= List->L.Depth)
            {
                /* All lists failed, use the pool */
                List->L.FreeMisses++;
                ExFreePool(Irp);
                Irp = NULL;
            }
        }

        /* The free was within the Depth */
        if (Irp)
        {
           InterlockedPushEntrySList(&List->L.ListHead,
                                     (PSINGLE_LIST_ENTRY)Irp);
        }
    }
}

/*
 * @implemented
 */
PEPROCESS NTAPI
IoGetRequestorProcess(IN PIRP Irp)
{
    return(Irp->Tail.Overlay.Thread->ThreadsProcess);
}

/*
 * @implemented
 */
ULONG
NTAPI
IoGetRequestorProcessId(IN PIRP Irp)
{
    return (ULONG)(IoGetRequestorProcess(Irp)->UniqueProcessId);
}

/*
 * @implemented
 */
NTSTATUS
NTAPI
IoGetRequestorSessionId(IN PIRP Irp,
                        OUT PULONG pSessionId)
{
    /* Return the session */
    *pSessionId = IoGetRequestorProcess(Irp)->Session;
    return STATUS_SUCCESS;
}

/*
 * @implemented
 */
PIRP
NTAPI
IoGetTopLevelIrp(VOID)
{
    return (PIRP)PsGetCurrentThread()->TopLevelIrp;
}

/*
 * @implemented
 */
VOID
NTAPI
IoInitializeIrp(IN PIRP Irp,
                IN USHORT PacketSize,
                IN CCHAR StackSize)
{
    /* Clear it */
    IOTRACE(IO_IRP_DEBUG,
            "%s - Initializing IRP %p\n",
            __FUNCTION__,
            Irp);
    RtlZeroMemory(Irp, PacketSize);

    /* Set the Header and other data */
    Irp->Type = IO_TYPE_IRP;
    Irp->Size = PacketSize;
    Irp->StackCount = StackSize;
    Irp->CurrentLocation = StackSize + 1;
    Irp->ApcEnvironment =  KeGetCurrentThread()->ApcStateIndex;
    Irp->Tail.Overlay.CurrentStackLocation = (PIO_STACK_LOCATION)(Irp + 1) + StackSize;

    /* Initialize the Thread List */
    InitializeListHead(&Irp->ThreadListEntry);
}

/*
 * @implemented
 */
BOOLEAN
NTAPI
IoIsOperationSynchronous(IN PIRP Irp)
{
    /* Check the flags */
    if (!(Irp->Flags & (IRP_PAGING_IO | IRP_SYNCHRONOUS_PAGING_IO)) &&
        ((Irp->Flags & IRP_SYNCHRONOUS_PAGING_IO) ||
         (Irp->Flags & IRP_SYNCHRONOUS_API) ||
         (IoGetCurrentIrpStackLocation(Irp)->FileObject->Flags &
          FO_SYNCHRONOUS_IO)))
    {
        /* Synch API or Paging I/O is OK, as is Sync File I/O */
        return TRUE;
    }

    /* Otherwise, it is an asynchronous operation. */
    return FALSE;
}

/*
 * @unimplemented
 */
BOOLEAN
NTAPI
IoIsValidNameGraftingBuffer(IN PIRP Irp,
                            IN PREPARSE_DATA_BUFFER ReparseBuffer)
{
    UNIMPLEMENTED;
    return FALSE;
}

/*
 * @implemented
 */
PIRP
NTAPI
IoMakeAssociatedIrp(IN PIRP Irp,
                    IN CCHAR StackSize)
{
    PIRP AssocIrp;
    IOTRACE(IO_IRP_DEBUG,
            "%s - Associating IRP %p\n",
            __FUNCTION__,
            Irp);

   /* Allocate the IRP */
   AssocIrp = IoAllocateIrp(StackSize, FALSE);
   if (!AssocIrp) return NULL;

   /* Set the Flags */
   AssocIrp->Flags |= IRP_ASSOCIATED_IRP;

   /* Set the Thread */
   AssocIrp->Tail.Overlay.Thread = Irp->Tail.Overlay.Thread;

   /* Associate them */
   AssocIrp->AssociatedIrp.MasterIrp = Irp;
   return AssocIrp;
}

/*
 * @implemented
 */
VOID
NTAPI
IoQueueThreadIrp(IN PIRP Irp)
{
    IOTRACE(IO_IRP_DEBUG,
            "%s - Queueing IRP %p\n",
            __FUNCTION__,
            Irp);

    /* Use our inlined routine */
    IopQueueIrpToThread(Irp);
}

/*
 * @implemented
 * Reference: Chris Cant's "Writing WDM Device Drivers"
 */
VOID
NTAPI
IoReuseIrp(IN OUT PIRP Irp,
           IN NTSTATUS Status)
{
    UCHAR AllocationFlags;
    IOTRACE(IO_IRP_DEBUG,
            "%s - Reusing IRP %p\n",
            __FUNCTION__,
            Irp);

    /* Make sure it's OK to reuse it */
    ASSERT(!Irp->CancelRoutine);
    ASSERT(IsListEmpty(&Irp->ThreadListEntry));

    /* Get the old flags */
    AllocationFlags = Irp->AllocationFlags;

    /* Reinitialize the IRP */
    IoInitializeIrp(Irp, Irp->Size, Irp->StackCount);

    /* Duplicate the data */
    Irp->IoStatus.Status = Status;
    Irp->AllocationFlags = AllocationFlags;
}

/*
 * @implemented
 */
VOID
NTAPI
IoSetTopLevelIrp(IN PIRP Irp)
{
    /* Set the IRP */
    PsGetCurrentThread()->TopLevelIrp = (ULONG)Irp;
}

/* EOF */