Question

priyeshwadhwa on Wed, 05 Mar 2014 10:03:15


I am facing issue while trying to retrieve SystemRestoreConfig class's RPSessionInterval variable using WMI calls. The call

hr = pclsObj->Get(L"RPSessionInterval", 0, &vtProp, &cimtype, 0);

returns vpProp as VT_NULL and cimtype as 0x13(CIM_UINT32). Now, cimtype is proper and msdn says that if VT_NULL is returned proper type will be in CIMTYPE. But where is the value of RPSessionInterval ?

http://msdn.microsoft.com/en-us/library/aa391442%28v=vs.85%29.aspx

http://msdn.microsoft.com/en-us/library/aa386309%28v=vs.85%29.aspx

#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\\DEFAULT"), // 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 << "Could not connect. Error code = 0x" 
             << hex << hres << endl;
        pLoc->Release();     
        CoUninitialize();
        return 1;                // Program has failed.
    }

    cout << "Connected to ROOT\\DEFAULT WMI namespace" << endl;


    // 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 SystemRestoreConfig"),
        WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, 
        NULL,
        &pEnumerator);
    
    if (FAILED(hres))
    {
        cout << "Query for SystemRestoreConfig 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 vtProp;

        // Get the value of the Name property
		CIMTYPE cimtype;
        hr = pclsObj->Get(L"RPSessionInterval", 0, &vtProp, &cimtype, 0);
        //wcout << " RPSessionInterval : " << vtProp.bstrVal << endl;
		wcout << " RPSessionInterval : " << cimtype<< endl;
        VariantClear(&vtProp);

        pclsObj->Release();
    }

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

    return 0;   // Program successfully completed.
 
}



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Replies

Renjith V Ramachandran on Wed, 05 Mar 2014 13:02:04


Try to get the same with below tool

WMI Explorer

priyeshwadhwa on Fri, 07 Mar 2014 15:32:27


Thanks Renjith,

WMI explorer is real good. But my motive is to have a C++ utility API through which I can determine if System restore is enabled or disabled. The code here is a sample tool written for verification of calls.

Also, when I ran WMIExplorer the output is blank for these RPSessionInterval. Attaching output of WMIExplorer.


Renjith V Ramachandran on Mon, 10 Mar 2014 08:44:34


Check the value of RPSessionInterval in vtProp.intVal

priyeshwadhwa on Sun, 27 Apr 2014 14:29:42


vpProp.intVal is garbage.(0xcccccccc)

Renjith V Ramachandran on Tue, 06 May 2014 07:49:51


vpProp.intVal is garbage.(0xcccccccc)

In WMIExplorer or in your code?

priyeshwadhwa on Wed, 18 Jun 2014 15:07:09


In my code. WMIExplorer is not showing anything for these properties.

smags13 on Thu, 18 Dec 2014 20:17:41


Hi, I'm seeing the same problem you've seen. Have you solved the problem?