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  4. Getting NULL value from 'Win32_LogonSession' through WMI [modified]

Getting NULL value from 'Win32_LogonSession' through WMI [modified]

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  • M Mark Salsbery

    Excellent thank you :) Change

    hr1 = pclsObj->>Get(_bstr_t(L"Win32_LogonSession.Name"), 0, &vtProp1, 0, 0);

    to this (changes marked in red)

    hr1 = pclsObj1->Get(_bstr_t(L"Name"), 0, &vtProp1, 0, 0);

    Mark

    Mark Salsbery Microsoft MVP - Visual C++ :java:

    S Offline
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    Supriya Tonape
    wrote on last edited by
    #20

    I had already tried that! It's not working as 'hr1' is getting as S_FALSE error and so 'vtProp1' is NULL for the time being... HRESULT hr1 = pEnumerator1->Next(WBEM_INFINITE, 1, &pclsObj1, &uReturn1); VARIANT vtProp1; hr1 = pclsObj1->Get(_bstr_t(L"Name"), 0, &vtProp1, 0, 0); :confused: Regards, Supriya Tonape

    M 1 Reply Last reply
    0
    • S Supriya Tonape

      I had already tried that! It's not working as 'hr1' is getting as S_FALSE error and so 'vtProp1' is NULL for the time being... HRESULT hr1 = pEnumerator1->Next(WBEM_INFINITE, 1, &pclsObj1, &uReturn1); VARIANT vtProp1; hr1 = pclsObj1->Get(_bstr_t(L"Name"), 0, &vtProp1, 0, 0); :confused: Regards, Supriya Tonape

      M Offline
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      Mark Salsbery
      wrote on last edited by
      #21

      hmm I tested it and it worked for me... Here's my test code - I took your code and added stuff to the top (copied right from that MSDN sample code) for me to build it...

      int GetRemoteLoggedOnUsers()
      {
      HRESULT hres = WBEM_S_NO_ERROR;

      //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"), // 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 (e.g. Kerberos)
           0,                       // Context object 
           &pSvc
      
      S 1 Reply Last reply
      0
      • M Mark Salsbery

        hmm I tested it and it worked for me... Here's my test code - I took your code and added stuff to the top (copied right from that MSDN sample code) for me to build it...

        int GetRemoteLoggedOnUsers()
        {
        HRESULT hres = WBEM_S_NO_ERROR;

        //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"), // 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 (e.g. Kerberos)
             0,                       // Context object 
             &pSvc
        
        S Offline
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        Supriya Tonape
        wrote on last edited by
        #22

        Mark :))))))))))))))))))))))))))) U are genious ! I am getting the name now :))thank you so much!!!!!!! Have a gr8 day ahead ! Best Regards, Supriya Tonape.

        M S 3 Replies Last reply
        0
        • S Supriya Tonape

          Mark :))))))))))))))))))))))))))) U are genious ! I am getting the name now :))thank you so much!!!!!!! Have a gr8 day ahead ! Best Regards, Supriya Tonape.

          M Offline
          M Offline
          Mark Salsbery
          wrote on last edited by
          #23

          You're welcome. You have a great day as well! :) Cheers, Mark

          Mark Salsbery Microsoft MVP - Visual C++ :java:

          1 Reply Last reply
          0
          • S Supriya Tonape

            Mark :))))))))))))))))))))))))))) U are genious ! I am getting the name now :))thank you so much!!!!!!! Have a gr8 day ahead ! Best Regards, Supriya Tonape.

            S Offline
            S Offline
            Supriya Tonape
            wrote on last edited by
            #24

            I am still wondering what exact mistake i was doing, all flags were set properly.. let me check in detail so I wont make it in future. Thx so much again. ! :) Regards, Supriya Tonape.

            1 Reply Last reply
            0
            • S Supriya Tonape

              Mark :))))))))))))))))))))))))))) U are genious ! I am getting the name now :))thank you so much!!!!!!! Have a gr8 day ahead ! Best Regards, Supriya Tonape.

              M Offline
              M Offline
              Mark Salsbery
              wrote on last edited by
              #25

              Also, if you remove the "WHERE LogonType = 2 OR LogonType = 10" from the outer query, you can see all logon sessions, not just the interactive ones. :) Mark

              Mark Salsbery Microsoft MVP - Visual C++ :java:

              S 1 Reply Last reply
              0
              • M Mark Salsbery

                Also, if you remove the "WHERE LogonType = 2 OR LogonType = 10" from the outer query, you can see all logon sessions, not just the interactive ones. :) Mark

                Mark Salsbery Microsoft MVP - Visual C++ :java:

                S Offline
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                Supriya Tonape
                wrote on last edited by
                #26

                yup Mark. You really made my day :) U have gr8 weekend ahead! Best Regards, Supriya.

                M 1 Reply Last reply
                0
                • S Supriya Tonape

                  yup Mark. You really made my day :) U have gr8 weekend ahead! Best Regards, Supriya.

                  M Offline
                  M Offline
                  Mark Salsbery
                  wrote on last edited by
                  #27

                  Supriya Tonape wrote:

                  U have gr8 weekend ahead!

                  Thank you....you too!

                  Mark Salsbery Microsoft MVP - Visual C++ :java:

                  S 1 Reply Last reply
                  0
                  • M Mark Salsbery

                    Supriya Tonape wrote:

                    U have gr8 weekend ahead!

                    Thank you....you too!

                    Mark Salsbery Microsoft MVP - Visual C++ :java:

                    S Offline
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                    Supriya Tonape
                    wrote on last edited by
                    #28

                    Also in this code though I have kept 'logontype' as 2 and 10 to get only active user names, but it;s returning me all users those are Disc earlier...

                    M 1 Reply Last reply
                    0
                    • S Supriya Tonape

                      Also in this code though I have kept 'logontype' as 2 and 10 to get only active user names, but it;s returning me all users those are Disc earlier...

                      M Offline
                      M Offline
                      Mark Salsbery
                      wrote on last edited by
                      #29

                      Supriya Tonape wrote:

                      but it;s returning me all users those are Disc earlier..

                      Which means what? :) Mark

                      Mark Salsbery Microsoft MVP - Visual C++ :java:

                      S 1 Reply Last reply
                      0
                      • M Mark Salsbery

                        Supriya Tonape wrote:

                        but it;s returning me all users those are Disc earlier..

                        Which means what? :) Mark

                        Mark Salsbery Microsoft MVP - Visual C++ :java:

                        S Offline
                        S Offline
                        Supriya Tonape
                        wrote on last edited by
                        #30

                        :) actually i will check it.. I just need usernames who has active session.

                        S 1 Reply Last reply
                        0
                        • S Supriya Tonape

                          :) actually i will check it.. I just need usernames who has active session.

                          S Offline
                          S Offline
                          Supriya Tonape
                          wrote on last edited by
                          #31

                          Hi Mark, I just realized that 2nd query which forms like "Associators of {Win32_LogonSession.LogonId=1121214} Where AssocClass=Win32_LoggedOnUser Role=Dependent" works for local machine but when I try to execute it on remote machine after above query executes, at next line it fails... Query execution passes but enumeration fails.. at below line, HRESULT hr1 = pEnumerator1->Next(WBEM_INFINITE, 1, &pclsObj1, &uReturn1); I have been trying different things to check out but no luck, any idea why it cud be happening or is there any change in query while running on remote machine ? Regards, Supriya Tonape

                          E 1 Reply Last reply
                          0
                          • S Supriya Tonape

                            Hi Mark, I just realized that 2nd query which forms like "Associators of {Win32_LogonSession.LogonId=1121214} Where AssocClass=Win32_LoggedOnUser Role=Dependent" works for local machine but when I try to execute it on remote machine after above query executes, at next line it fails... Query execution passes but enumeration fails.. at below line, HRESULT hr1 = pEnumerator1->Next(WBEM_INFINITE, 1, &pclsObj1, &uReturn1); I have been trying different things to check out but no luck, any idea why it cud be happening or is there any change in query while running on remote machine ? Regards, Supriya Tonape

                            E Offline
                            E Offline
                            etaig
                            wrote on last edited by
                            #32

                            Hi All, For some reason, when I add the following lines, to get the StartTime property value, the get function fails. Any ideas?

                            VARIANT vtProp2;
                            HRESULT hr2 = pclsObj1->Get(L"StartTime", 0, &vtProp2, 0, 0);
                            if(hr1 == S_OK)
                            {
                            SYSTEMTIME t;
                            int res = VariantTimeToSystemTime(vtProp2.dblVal, &t);
                            }

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