Windows WMI Example to: 1. Get properties from WMI Class 2. Execute methods provided by WMI Class

GetBitLockerStatus.cpp

#define _WIN32_DCOM
#include <iostream>
using namespace std;
#include <comdef.h>
#include <Wbemidl.h>

# pragma comment(lib, "wbemuuid.lib")

int main(int argc, char **argv)
{
    HRESULT hres;

    // Step 1: --------------------------------------------------
    // Initialize COM. ------------------------------------------

    hres =  CoInitializeEx(0, COINIT_MULTITHREADED); 
    if (FAILED(hres)) {
        cout << "Failed to initialize COM library. Error code = 0x" 
             << hex << hres << endl;
        return 1;                    // Program has failed.
    }

    // Step 2: --------------------------------------------------
    // Set general COM security levels --------------------------

    hres =  CoInitializeSecurity(
        NULL, 
        -1,                          // COM authentication
        NULL,                        // Authentication services
        NULL,                        // Reserved
        RPC_C_AUTHN_LEVEL_DEFAULT,   // Default authentication 
        RPC_C_IMP_LEVEL_IMPERSONATE, // Default Impersonation  
        NULL,                        // Authentication info
        EOAC_NONE,                   // Additional capabilities 
        NULL                         // Reserved
        );

    if (FAILED(hres)) {
        cout << "Failed to initialize security. Error code = 0x" 
             << hex << hres << endl;
        CoUninitialize();
        return 1;                    // Program has failed.
    }
    
    // Step 3: ---------------------------------------------------
    // Obtain the initial locator to WMI -------------------------

    IWbemLocator *pLoc = NULL;

    hres = CoCreateInstance(
        CLSID_WbemLocator,             
        0, 
        CLSCTX_INPROC_SERVER, 
        IID_IWbemLocator, (LPVOID *) &pLoc);
 
    if (FAILED(hres)) {
        cout << "Failed to create IWbemLocator object."
             << " Err code = 0x"
             << hex << hres << endl;
        CoUninitialize();
        return 1;                    // Program has failed.
    }

    // Step 4: -----------------------------------------------------
    // Connect to WMI through the IWbemLocator::ConnectServer method

    IWbemServices *pSvc = NULL;
 
    // Connect to the root\cimv2 namespace with
    // the current user and obtain pointer pSvc
    // to make IWbemServices calls.
    hres = pLoc->ConnectServer(
         _bstr_t(L"ROOT\\CIMV2\\Security\\MicrosoftVolumeEncryption"),
                                     // Object path of WMI namespace
         NULL,                       // User name. NULL = current user
         NULL,                       // User password. NULL = current
         0,                          // Locale. NULL indicates current
         NULL,                       // Security flags.
         0,                          // Authority (for example, Kerberos)
         0,                          // Context object 
         &pSvc                       // pointer to IWbemServices proxy
         );
    
    if (FAILED(hres)) {
        cout << "Unable to connect, are you administrator? Error code = 0x" 
             << hex << hres << endl;
        pLoc->Release();     
        CoUninitialize();
        return 1;                    // Program has failed.
    }

    // Step 5: --------------------------------------------------
    // Set security levels on the proxy -------------------------

    hres = CoSetProxyBlanket(
       pSvc,                         // Indicates the proxy to set
       RPC_C_AUTHN_WINNT,            // RPC_C_AUTHN_xxx
       RPC_C_AUTHZ_NONE,             // RPC_C_AUTHZ_xxx
       NULL,                         // Server principal name 
       RPC_C_AUTHN_LEVEL_CALL,       // RPC_C_AUTHN_LEVEL_xxx 
       RPC_C_IMP_LEVEL_IMPERSONATE,  // RPC_C_IMP_LEVEL_xxx
       NULL,                         // client identity
       EOAC_NONE                     // proxy capabilities 
    );

    if (FAILED(hres)) {
        cout << "Could not set proxy blanket. Error code = 0x" 
             << hex << hres << endl;
        pSvc->Release();
        pLoc->Release();     
        CoUninitialize();
        return 1;                    // Program has failed.
    }

    // Step 6: --------------------------------------------------
    // Use the IWbemServices pointer to make requests of WMI ----

    // For example, get the name of the operating system
    IEnumWbemClassObject* pEnumerator = NULL;
    hres = pSvc->ExecQuery(
        bstr_t("WQL"), 
        bstr_t("SELECT * FROM Win32_EncryptableVolume"),
        WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, 
        NULL,
        &pEnumerator);
    
    if (FAILED(hres)) {
        cout << "Query for operating system name failed."
             << " Error code = 0x" 
             << hex << hres << endl;
        pSvc->Release();
        pLoc->Release();
        CoUninitialize();
        return 1;                    // Program has failed.
    }

    // Step 7: -------------------------------------------------
    // Get the data from the query in step 6 -------------------
 
    IWbemClassObject *pclsObj;
    ULONG uReturn = 0;
   
    while (pEnumerator) {
        HRESULT hr = pEnumerator->Next(WBEM_INFINITE, 1, 
            &pclsObj, &uReturn);

        if (0 == uReturn) break;

        VARIANT vtPropDriveLetter, vtPropProtectionStatus;

        // Get the value of the Name property
        hr = pclsObj->Get(L"DriveLetter", 0, &vtPropDriveLetter, 0, 0);
        if (!FAILED(hr))
            wcout << " DriveLetter : " << vtPropDriveLetter.bstrVal << endl;
        VariantClear(&vtPropDriveLetter);

        hr = pclsObj->Get(L"ProtectionStatus", 0, &vtPropProtectionStatus, 0, 0);
        if (!FAILED(hr))
            wcout << " ProtectionStatus : " << vtPropProtectionStatus.intVal << endl;
        VariantClear(&vtPropProtectionStatus);

        pclsObj->Release();
    }

    // Cleanup
    // ========

    pSvc->Release();
    pLoc->Release();
    pEnumerator->Release();
    if (!pclsObj) pclsObj->Release();
    CoUninitialize();

    return 0;   // Program successfully completed.
}

GetTpmStatus.cpp

#define _WIN32_DCOM
#include <iostream>
using namespace std;
#include <comdef.h>
#include <wbemidl.h>
#pragma comment(lib, "wbemuuid.lib")

int main(int argc, char ** argv)
{
    HRESULT hres;
    BOOLEAN isComInit = FALSE;
    BSTR MethodName = SysAllocString(L"IsEnabled");
    BSTR ClassName = SysAllocString(L"Win32_Tpm=@");
    IWbemLocator *pLoc = NULL;
    IWbemServices *pSvc = NULL;
    IWbemClassObject* pClass = NULL;
    IWbemClassObject* pOutputDefinition = NULL;
    VARIANT varClassPath, varReturn;

    hres = CoInitializeEx(0, COINIT_MULTITHREADED);
    if (FAILED(hres)) {
        cout << "Failed to initialize COM library. Error code = 0x"
             << hex << hres << endl;
        return 1;
    }
    isComInit = TRUE;

    hres =  CoInitializeSecurity(
                NULL,
                -1,                              // COM negotiates service
                NULL,                            // Authentication services
                NULL,                            // Reserved
                RPC_C_AUTHN_LEVEL_DEFAULT,       // Default authentication
                RPC_C_IMP_LEVEL_IMPERSONATE,     // Default Impersonation
                NULL,                            // Authentication info
                EOAC_NONE,                       // Additional capabilities
                NULL);                           // Reserved

    if (FAILED(hres)) {
        cout << "Failed to initialize security. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    hres = CoCreateInstance(
            CLSID_WbemLocator,
            0,
            CLSCTX_INPROC_SERVER,
            IID_IWbemLocator,
            (LPVOID *)&pLoc);

    if (FAILED(hres)) {
        cout << "Failed to create IWbemLocator object. "
             << "Err code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    hres = pLoc->ConnectServer(
                    _bstr_t(L"ROOT\\CIMV2\\Security\\MicrosoftTpm"),
                    NULL,
                    NULL,
                    0,
                    NULL,
                    0,
                    0,
                    &pSvc);

    if (FAILED(hres)) {
        cout << "Could not connect. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    hres = CoSetProxyBlanket(
            pSvc,                                // Indicates the proxy to set
            RPC_C_AUTHN_WINNT,                   // RPC_C_AUTHN_xxx
            RPC_C_AUTHZ_NONE,                    // RPC_C_AUTHZ_xxx
            NULL,                                // Server principal name
            RPC_C_AUTHN_LEVEL_CALL,              // RPC_C_AUTHN_LEVEL_xxx
            RPC_C_IMP_LEVEL_IMPERSONATE,         // RPC_C_IMP_LEVEL_xxx
            NULL,                                // client identity
            EOAC_NONE);                          // proxy capabilities

    if (FAILED(hres)) {
        cout << "Could not set proxy blanket. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    hres = pSvc->GetObject(ClassName, 0, NULL, &pClass, NULL);
    if (FAILED(hres)) {
        cout << "Could not get class. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    VariantInit(&varClassPath);
    hres = pClass->Get(_bstr_t(L"__PATH"), 0, &varClassPath, NULL, NULL);
    if (FAILED(hres)) {
        cout << "Could not get class path. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    hres = pSvc->ExecMethod(
                    varClassPath.bstrVal,
                    MethodName,
                    0,
                    NULL,
                    NULL,
                    &pOutputDefinition,
                    NULL);
    if (FAILED(hres)) {
        cout << "Could not execute method. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    hres = pOutputDefinition->Get(_bstr_t(L"IsEnabled"), 0, &varReturn, NULL, 0);
    if (FAILED(hres)) {
        cout << "Could not get return object. Error code = 0x"
             << hex << hres << endl;
        goto Finale;
    }

    cout << "TPM IsEnabled() : " << varReturn.boolVal << endl;

Finale:
    SysFreeString(MethodName);
    SysFreeString(ClassName);
    if (pClass) pClass->Release();
    if (pOutputDefinition) pOutputDefinition->Release();
    if (pSvc) pSvc->Release();
    if (pLoc) pLoc->Release();
    if (isComInit) CoUninitialize();

    return 0;
}