NTSTATUS DEFAULTAPI MsfsRead	(	PDEVICE_OBJECT	DeviceObject,
		PIRP	Irp
	)
Definition at line 20 of file rw.c.
{
    PIO_STACK_LOCATION IoStack;
    PFILE_OBJECT FileObject;
    PMSFS_FCB Fcb;
    PMSFS_CCB Ccb;
    PMSFS_MESSAGE Message;
    KIRQL oldIrql;
    ULONG Length;
    ULONG LengthRead = 0;
    PVOID Buffer;
    NTSTATUS Status;

    DPRINT("MsfsRead(DeviceObject %p Irp %p)\n", DeviceObject, Irp);

    IoStack = IoGetCurrentIrpStackLocation (Irp);
    FileObject = IoStack->FileObject;
    Fcb = (PMSFS_FCB)FileObject->FsContext;
    Ccb = (PMSFS_CCB)FileObject->FsContext2;

    DPRINT("MailslotName: %wZ\n", &Fcb->Name);

    /* reading is not permitted on client side */
    if (Fcb->ServerCcb != Ccb)
    {
        Irp->IoStatus.Status = STATUS_ACCESS_DENIED;
        Irp->IoStatus.Information = 0;

        IoCompleteRequest(Irp, IO_NO_INCREMENT);

        return STATUS_ACCESS_DENIED;
    }

    Length = IoStack->Parameters.Read.Length;
    if (Irp->MdlAddress)
        Buffer = MmGetSystemAddressForMdl (Irp->MdlAddress);
    else
        Buffer = Irp->UserBuffer;

    Status = KeWaitForSingleObject(&Fcb->MessageEvent,
                                   UserRequest,
                                   KernelMode,
                                   FALSE,
                                   &Fcb->TimeOut);
    if (NT_SUCCESS(Status))
    {
        if (Fcb->MessageCount > 0)
        {
            /* copy current message into buffer */
            Message = CONTAINING_RECORD(Fcb->MessageListHead.Flink,
                                        MSFS_MESSAGE,
                                        MessageListEntry);

            memcpy(Buffer, &Message->Buffer, min(Message->Size,Length));
            LengthRead = Message->Size;

            KeAcquireSpinLock(&Fcb->MessageListLock, &oldIrql);
            RemoveHeadList(&Fcb->MessageListHead);
            KeReleaseSpinLock(&Fcb->MessageListLock, oldIrql);

            ExFreePool(Message);
            Fcb->MessageCount--;
            if (Fcb->MessageCount == 0)
            {
                KeClearEvent(&Fcb->MessageEvent);
            }
        }
        else if (Fcb->TimeOut.QuadPart != 0LL)
        {
            /* No message found after waiting */
            Status = STATUS_IO_TIMEOUT;
        }
     }

    Irp->IoStatus.Status = Status;
    Irp->IoStatus.Information = LengthRead;

    IoCompleteRequest(Irp, IO_NO_INCREMENT);

    return Status;
}
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