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使用注册表项对象的句柄

  • 项目

下表列出了驱动程序可以对打开键执行的操作以及要调用的相应例程。

Operation 要调用的例程

检查密钥的属性，例如其名称或其子项的数目。

ZwQueryKey

循环访问密钥的子项，检查每个子项的属性。

ZwEnumerateKey

检查键值的属性，包括值的数据。

ZwQueryValueKey

循环访问键的值，检查每个键的属性。

ZwEnumerateValueKey

为与键关联的值设置数据。

ZwSetValueKey

删除密钥。

ZwDeleteKey

删除键值。

ZwDeleteValueKey

驱动程序完成其操作后，必须调用 ZwClose 以关闭句柄，即使它已调用 ZwDeleteKey 来删除密钥。 (删除密钥后，其所有打开的句柄将变为无效，但驱动程序仍必须关闭 handle.)

下面的代码示例演示了如何为名为 \Registry\Machine\Software\MyCompanyMyApp 的\项打开句柄，然后检索密钥数据并关闭句柄。

//
// Get the frame location from the registry key
// HKLM\SOFTWARE\MyCompany\MyApp.
// For example: "FrameLocation"="X:\\MyApp\\Frames"
// 
HANDLE              handleRegKey = NULL;
for (int n = 0; n < 1; n++) 
{
    NTSTATUS           status = NULL;
    UNICODE_STRING     RegistryKeyName;
    OBJECT_ATTRIBUTES  ObjectAttributes;

    RtlInitUnicodeString(&RegistryKeyName, L"\\Registry\\Machine\\Software\\MyCompany\\MyApp");
    InitializeObjectAttributes(&ObjectAttributes, 
                               &RegistryKeyName,
                               OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
                               NULL,    // handle
                               NULL);
    status = ZwOpenKey(&handleRegKey, KEY_READ, &ObjectAttributes);

    // If the driver cannot open the key, the driver cannot continue. 
    // In this situation, the driver was probably set up incorrectly 
    // and worst case, the driver cannot stream.
    if( NT_SUCCESS(status) == FALSE ) 
    {
        break;
    }
    // The driver obtained the registry key.
    PKEY_VALUE_FULL_INFORMATION  pKeyInfo = NULL;
    UNICODE_STRING               ValueName;
    ULONG                        ulKeyInfoSize = 0;
    ULONG                        ulKeyInfoSizeNeeded = 0;

    // The driver requires the following value.
    RtlInitUnicodeString(&ValueName, L"FrameLocation");

    // Determine the required size of keyInfo.
    status = ZwQueryValueKey( handleRegKey,
                              &ValueName,
                              KeyValueFullInformation,
                              pKeyInfo,
                              ulKeyInfoSize,
                              &ulKeyInfoSizeNeeded );

    // The driver expects one of the following errors.
    if( (status == STATUS_BUFFER_TOO_SMALL) || (status == STATUS_BUFFER_OVERFLOW) )
    {
        // Allocate the memory required for the key.
        ulKeyInfoSize = ulKeyInfoSizeNeeded;
        pKeyInfo = (PKEY_VALUE_FULL_INFORMATION) ExAllocatePoolWithTag( NonPagedPool, ulKeyInfoSizeNeeded, g_ulTag);
        if( NULL == pKeyInfo )
        {
            break;
        }
        RtlZeroMemory( pKeyInfo, ulKeyInfoSize );

        // Get the key data.
        status = ZwQueryValueKey( handleRegKey,
                                  &ValueName,
                                  KeyValueFullInformation,
                                  pKeyInfo,
                                  ulKeyInfoSize,
                                  &ulKeyInfoSizeNeeded );
        if( (status != STATUS_SUCCESS) || (ulKeyInfoSizeNeeded != ulKeyInfoSize) || (NULL == pKeyInfo) )
        {
            break;
        }

        // Fill in the frame location if it has not been filled in already.
        if ( NULL == m_szwFramePath )
        {
            m_ulFramePathLength = pKeyInfo->DataLength;
            ULONG_PTR   pSrc = NULL;

            pSrc = (ULONG_PTR) ( (PBYTE) pKeyInfo + pKeyInfo->DataOffset);

            m_szwFramePath = (LPWSTR) ExAllocatePoolWithTag( NonPagedPool, m_ulFramePathLength, g_ulTag);
            if ( NULL == m_szwFramePath )
            {
                m_ulFramePathLength = 0;
                break;
            }

            // Copy the frame path.
            RtlCopyMemory(m_szwFramePath, (PVOID) pSrc, m_ulFramePathLength);
        }
        // The driver is done with the pKeyInfo.
        xFreePoolWithTag(pKeyInfo, g_ulTag);

    } // if( (status == STATUS_BUFFER_TOO_SMALL) || (status == STATUS_BUFFER_OVERFLOW) )
} // Get the Frame location from the registry key.

// All done with the registry.
if (NULL != handleRegKey)
{
    ZwClose(handleRegKey);
}

系统缓存内存中的密钥更改，并每隔几秒将其写入磁盘。 若要强制更改磁盘的密钥，请调用 ZwFlushKey。

若要通过更简单的接口操作注册表，驱动程序还可以调用 RtlXxx注册表Xxx 例程。 有关详细信息，请参阅 注册表Run-Time库例程。