WdfDeviceOpenRegistryKey - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
// wdfdevice.h
NTSTATUS WdfDeviceOpenRegistryKey(
[in] WDFDEVICE Device,
[in] ULONG DeviceInstanceKeyType,
[in] ACCESS_MASK DesiredAccess,
[in, optional] PWDF_OBJECT_ATTRIBUTES KeyAttributes,
[out] WDFKEY *Key
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF and UMDF]
The WdfDeviceOpenRegistryKey method opens a device's hardware key or a driver's software key in the registry and creates a framework registry-key object that represents the registry key.
Device [in]A handle to a framework device object.
DeviceInstanceKeyType [in]Specifies which key or subkey to open.
[!NOTE] UMDF does not support creating subkeys.
This is a bitwise OR of the following flags (which are defined in Wdm.h).
| DeviceInstanceKeyType flag | Meaning | Framework | |
|---|---|---|---|
| PLUGPLAY_REGKEY_DEVICE | Opens the device's hardware key. | KMDF/UMDF | |
| PLUGPLAY_REGKEY_DRIVER | Opens the driver's software key. A UMDF driver that sets this flag must also set DesiredAccess to KEY_READ. Otherwise this method returns STATUS_ACCESS_DENIED. | KMDF/UMDF | |
| PLUGPLAY_REGKEY_CURRENT_HWPROFILE | A KMDF driver uses this flag to open the copy of the hardware or software key that is in the current hardware profile. | KMDF | |
| **PLUGPLAY_REGKEY_DRIVER | WDF_REGKEY_DRIVER_SUBKEY** | A UMDF driver uses these flags together to open the ServiceName subkey of the driver's software key for read/write access. | UMDF |
| **PLUGPLAY_REGKEY_DEVICE | WDF_REGKEY_DEVICE_SUBKEY** | Similarly, a UMDF driver uses these flags to open the ServiceName subkey of the device's hardware key for read/write access. | UMDF |
DesiredAccess [in]An ACCESS_MASK-typed value that specifies access rights that the driver is requesting for the specified registry key.
A KMDF driver typically requests KEY_READ, KEY_WRITE, or KEY_READ | KEY_WRITE.
If you are writing a UMDF driver, use the following table.
| DeviceInstanceKeyType | DesiredAccess | ||
|---|---|---|---|
| PLUGPLAY_REGKEY_DEVICE | KEY_READ | ||
| **PLUGPLAY_REGKEY_DEVICE | WDF_REGKEY_DEVICE_SUBKEY** | KEY_READ or **KEY_READ | KEY_SET_VALUE** |
| PLUGPLAY_REGKEY_DRIVER | KEY_READ | ||
| **PLUGPLAY_REGKEY_DRIVER | WDF_REGKEY_DRIVER_SUBKEY** | KEY_READ or **KEY_READ | KEY_SET_VALUE** |
As a best practice, ask for only the types of access that your driver needs.
KeyAttributes [in, optional]A pointer to a WDF_OBJECT_ATTRIBUTES structure that contains driver-supplied attributes for the new registry-key object. This parameter is optional and can be WDF_NO_OBJECT_ATTRIBUTES.
Key [out]A pointer to a location that receives a handle to the new registry-key object.
WdfDeviceOpenRegistryKey returns STATUS_SUCCESS if the operation succeeds. Otherwise, the method might return one of the following values:
| Return code | Description |
|---|---|
| STATUS_INVALID_DEVICE_REQUEST | WdfDeviceOpenRegistryKey was not called at IRQL = PASSIVE_LEVEL. |
| STATUS_INVALID_PARAMETER | An invalid parameter was specified. For UMDF, this return value can indicate insufficient access rights. |
| STATUS_INSUFFICIENT_RESOURCES | A registry-key object could not be allocated. |
| STATUS_OBJECT_NAME_NOT_FOUND | The specified registry key does not exist. |
For a list of other return values that the WdfDeviceOpenRegistryKey method might return, see Framework Object Creation Errors.
The method might return other NTSTATUS values.
A bug check occurs if the driver supplies an invalid object handle.
If your driver must open a hardware or software key before it has called WdfDeviceCreate, it must call WdfFdoInitOpenRegistryKey instead of WdfDeviceOpenRegistryKey.
When the driver has finished using the registry key that it opened with WdfDeviceOpenRegistryKey, the driver must call WdfRegistryClose.
For more information about the registry, hardware and software keys, and registry objects, see Using the Registry in Framework-Based Drivers.
For code examples that use WdfDeviceOpenRegistryKey, see WdfRegistryCreateKey, WdfRegistryOpenKey, and WdfRegistryQueryValue.