WdfFdoInitOpenRegistryKey - NtDoc
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// wdffdo.h
NTSTATUS WdfFdoInitOpenRegistryKey(
[in] PWDFDEVICE_INIT DeviceInit,
[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 WdfFdoInitOpenRegistryKey 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.
DeviceInit [in]A pointer to a WDFDEVICE_INIT structure that the driver obtained from its EvtDriverDeviceAdd callback function.
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.
WdfFdoInitOpenRegistryKey returns STATUS_SUCCESS if the operation succeeds. Otherwise, the method might return one of the following values:
| Return code | Description |
|---|---|
| STATUS_INVALID_DEVICE_REQUEST | WdfFdoInitOpenRegistryKey was not called at IRQL = PASSIVE_LEVEL. |
| STATUS_INVALID_PARAMETER | An invalid parameter was specified, or the driver did not obtain the WDFDEVICE_INIT structure from its EvtDriverDeviceAdd callback function. 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 WdfFdoInitOpenRegistryKey method might return, see Framework Object Creation Errors.
The method might also return other NTSTATUS values.
The driver must call WdfFdoInitOpenRegistryKey before calling WdfDeviceCreate. For more information about calling WdfDeviceCreate, see Creating a Framework Device Object.
For more information about the WdfFdoInitOpenRegistryKey method, see Creating Device Objects in a Function Driver.
or more information about the registry, hardware and software keys, and registry objects, see Using the Registry in Framework-Based Drivers.
The following code example opens a device's hardware key, with read access.
WDFKEY key;
NTSTATUS status;
status = WdfFdoInitOpenRegistryKey(
DeviceInit,
PLUGPLAY_REGKEY_DEVICE,
GENERIC_READ,
WDF_NO_OBJECT_ATTRIBUTES,
&key
);
if (!NT_SUCCESS(status)) {
return status;
}
WdfDriverOpenParametersRegistryKey