#include <ntddk.h>
#include "ntifs.h"

NTSTATUS
DriverEntry (
    IN PDRIVER_OBJECT   DriverObject,
    IN PUNICODE_STRING  RegistryPath
    )
{
    UNICODE_STRING              parameter_path;//備份注冊表設備服務鍵的鍵名
    RTL_QUERY_REGISTRY_TABLE    query_table[2];//保存查詢注冊表樹時返回相應鍵的內容
    ULONG                       n_devices;//支持的設備個數
    NTSTATUS                    status;//狀態值，具體請參閱ntstatus.h
    UNICODE_STRING              device_dir_name;//保存目錄設備名
    OBJECT_ATTRIBUTES           object_attributes;//保存對象屬性
    ULONG                       n;
    USHORT                      n_created_devices;

	//初始化parameter_path
    parameter_path.Length = 0;

    parameter_path.MaximumLength = RegistryPath->Length + sizeof(PARAMETER_KEY);

    parameter_path.Buffer = (PWSTR) ExAllocatePool(PagedPool, parameter_path.MaximumLength);

    if (parameter_path.Buffer == NULL)
    {
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlCopyUnicodeString(&parameter_path, RegistryPath);

    RtlAppendUnicodeToString(&parameter_path, PARAMETER_KEY);

    RtlZeroMemory(&query_table[0], sizeof(query_table));

    query_table[0].Flags = RTL_QUERY_REGISTRY_DIRECT | RTL_QUERY_REGISTRY_REQUIRED;
	//RTL_QUERY_REGISTRY_DIRECT在ntddk.h中定義為0x00000020
	//RTL_QUERY_REGISTRY_REQUIRED在ntddk.h中定義為0x00000004
	//結果應為0x00000024

    query_table[0].Name = NUMBEROFDEVICES_VALUE;
	//NUMBEROFDEVICES_VALUE在ntifs中定義為L"NumberOfDevices"
 
    query_table[0].EntryContext = &n_devices;

    status = RtlQueryRegistryValues(
        RTL_REGISTRY_ABSOLUTE,
        parameter_path.Buffer,
        &query_table[0],
        NULL,
        NULL
        );
	//RTL_REGISTRY_ABSOLUTE在ntddk.h中定義為0，代表路徑為完全路徑

    ExFreePool(parameter_path.Buffer);

    if (!NT_SUCCESS(status))
    {
        KdPrint(("FileDisk: Query registry failed, using default values.\n"));
        n_devices = DEFAULT_NUMBEROFDEVICES;
    }

    RtlInitUnicodeString(&device_dir_name, DEVICE_DIR_NAME);

    InitializeObjectAttributes(
        &object_attributes,
        &device_dir_name,
        OBJ_PERMANENT,
        NULL,
        NULL
        );
	//OBJ_PERMANENT在ntdef.h中定義為0x00000010L

    status = ZwCreateDirectoryObject(
        &dir_handle,
        DIRECTORY_ALL_ACCESS,
        &object_attributes
        );
	//DIRECTORY_ALL_ACCESS在ntddk.h中定義為(STANDARD_RIGHTS_REQUIRED | 0xF)
	//即為STANDARD_RIGHTS_REQUIRED與0xF按位或
	//STANDARD_RIGHTS_REQUIRED在ntddk.h中定義為0x000F0000L

    if (!NT_SUCCESS(status))
    {
        return status;
    }

    ZwMakeTemporaryObject(dir_handle);

    for (n = 0, n_created_devices = 0; n < n_devices; n++)
    {
        status = FileDiskCreateDevice(DriverObject, n, FILE_DEVICE_DISK);

        if (NT_SUCCESS(status))
        {
            n_created_devices++;
        }
    }

    ////for (n = 0; n < n_devices; n++)
    ////{
    ////    status = FileDiskCreateDevice(DriverObject, n, FILE_DEVICE_CD_ROM);

    ////    if (NT_SUCCESS(status))
    ////    {
    ////       n_created_devices++;
    ////    }
    ////}

    if (n_created_devices == 0)
    {
        ZwClose(dir_handle);
        return status;
    }

    DriverObject->MajorFunction[IRP_MJ_CREATE]         = FileDiskCreateClose;
    DriverObject->MajorFunction[IRP_MJ_CLOSE]          = FileDiskCreateClose;
    DriverObject->MajorFunction[IRP_MJ_READ]           = FileDiskReadWrite;
    DriverObject->MajorFunction[IRP_MJ_WRITE]          = FileDiskReadWrite;
    DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = FileDiskDeviceControl;
	//常用的IRP主功能代碼
	//IRP_MJ_CREATE：創建或打開設備文件，ntddk.h中定義為0x00
	//IRP_MJ_CLOSE：關閉句柄，ntddk.h中定義為0x02
	//IRP_MJ_READ：讀，ntddk.h中定義為0x03
	//IRP_MJ_WRITE：寫，ntddk.h中定義為0x04
	//IRP_MJ_CLEANUP：取消文件句柄上的任何等待的IRP，ntddk.h中定義為0x12
	//IRP_MJ_DEVICE_CONTROL：設備I/O控制，ntddk.h中定義為0x0e
	//IRP_MJ_INTERNAL_DEVICE_CONTROL(IRP_MJ_SCSI)：來自高層驅動程序的設備I/O控制，ntddk.h中定義為0x0f
	//IRP_MJ_SYSTEM_CONTROL：WMI，ntddk.h中定義為0x17
	//IRP_MJ_POWER：電源管理請求，ntddk.h中定義為0x16
	//IRP_MJ_PNP：即插即用消息，ntddk.h中定義為0x1b
	//IRP_MJ_SHUTDOWN：關閉通知，ntddk.h中定義為0x10

    DriverObject->DriverUnload = FileDiskUnload;

    return STATUS_SUCCESS;
}