在驱动中怎么读取注册表中某项内容

首先我用外部程序在注册中填入注册信息
然后想从注册表读取路径信息。

这是FileSpy中的一段代码，你参考参考。
DBGSTATIC
VOID
SpyReadDriverParameters (
    IN     PUNICODE_STRING  RegistryPath,
    IN     PDRIVER_OBJECT   DriverObject
    )
/*++

Routine Description:

    This routine tries to read the FileSpy-specific parameters from
    the registry.  These values will be found in the registry location
    indicated by the RegistryPath passed in.

Arguments:

    RegistryPath - the path key which contains the values that are
        the FileSpy parameters

Return Value:

    None.
CallStack:
Called by DriverEntry routine
--*/
{

    OBJECT_ATTRIBUTES              attributes;
    HANDLE                         driverRegKey;
    NTSTATUS                       status;
    ULONG                          bufferSize, resultLength;
    PVOID                          buffer = NULL;
    ULONG                          keyIndex;
    UNICODE_STRING                 valueName;
    PKEY_VALUE_PARTIAL_INFORMATION pValuePartialInfo;
    PWSTR                          attachDrives;

    InitializeObjectAttributes(
        &attributes,
        RegistryPath,
        OBJ_CASE_INSENSITIVE,
        NULL,
        NULL);

    status = ZwOpenKey(
        &driverRegKey,
        KEY_READ,
        &attributes);

    if (!NT_SUCCESS(status)) {
        driverRegKey = NULL;
        goto SpyReadDriverParameters_Error;
    }

    bufferSize = sizeof(KEY_VALUE_PARTIAL_INFORMATION) + ATTACH_BUFFER_SIZE;
    buffer = ExAllocatePool(NonPagedPool, bufferSize);

    if (NULL == buffer) {
        goto SpyReadDriverParameters_Error;
    }

    //
    // Read the gMaxRecordsToAllocate from the registry
    //
    RtlInitUnicodeString(&valueName, MAX_RECORDS_TO_ALLOCATE);

    status = ZwQueryValueKey(
        driverRegKey,
        &valueName,
        KeyValuePartialInformation,
        buffer,
        bufferSize,
        &resultLength);

    if (NT_SUCCESS(status)) {
        pValuePartialInfo = (PKEY_VALUE_PARTIAL_INFORMATION) buffer;
        ASSERT(pValuePartialInfo->Type == REG_DWORD);
        gMaxRecordsToAllocate = *((PLONG)&(pValuePartialInfo->Data));
    } else {
        gMaxRecordsToAllocate = DEFAULT_MAX_RECORDS_TO_ALLOCATE;
    }

    //
    // Read the gMaxNamesToAllocate from the registry
    //
    RtlInitUnicodeString(&valueName, MAX_NAMES_TO_ALLOCATE);

    status = ZwQueryValueKey(
        driverRegKey,
        &valueName,
        KeyValuePartialInformation,
        buffer,
        bufferSize,
        &resultLength);

    if (NT_SUCCESS(status)) {
        pValuePartialInfo = (PKEY_VALUE_PARTIAL_INFORMATION) buffer;
        ASSERT(pValuePartialInfo->Type == REG_DWORD);
        gMaxNamesToAllocate = *((PLONG)&(pValuePartialInfo->Data));
    } else {
        gMaxNamesToAllocate = DEFAULT_MAX_NAMES_TO_ALLOCATE;
    }


#ifdef SPY_BOOT_DRIVER
    //
    // Read initial drives to attach to from the registry
    //

    RtlInitUnicodeString(&valueName, ATTACH_TO);

    status = ZwQueryValueKey(
        driverRegKey,
        &valueName,
        KeyValuePartialInformation,
        buffer,
        bufferSize,
        &resultLength);

    if (NT_SUCCESS(status)) {

        pValuePartialInfo = (PKEY_VALUE_PARTIAL_INFORMATION) buffer;
        if(pValuePartialInfo->Type != REG_MULTI_SZ){
            goto SpyReadDriverParameters_Exit;
        }


        attachDrives = (PWSTR)&pValuePartialInfo->Data;
        if(*attachDrives){
            //
            //  Register with the I/O System to be called again once all the
            //  devices in the system have been enumerated and started.
            //
            IoRegisterBootDriverReinitialization(DriverObject, SpyReinitDriver, buffer);
            //
            // In this instance, SpyReinitDriver will free buffer when it is done parsing and attaching.
            //
            buffer = NULL;
        }
    }
#endif

    goto SpyReadDriverParameters_Exit;

SpyReadDriverParameters_Error:
    gMaxRecordsToAllocate = DEFAULT_MAX_RECORDS_TO_ALLOCATE;
    gMaxNamesToAllocate = DEFAULT_MAX_NAMES_TO_ALLOCATE;

SpyReadDriverParameters_Exit:
    if (NULL != buffer) {
        ExFreePool(buffer);
    }
    if (NULL != driverRegKey) {
        ZwClose(driverRegKey);
    }

    return;
}