Discussion :

[Invité]

Bonjour,

Dans la documentation de l'API Win32, les exemples de connexion à WMI sont écrits en Vbscript ou C++.

Est-il possible de se connecter à WMI en utilisant C ? Si oui, avez-vous un exemple à me montrer car je n'ai rien trouvé à ce sujet.

Merci beaucoup.

[bacelar]

L'API WMI fait partie de Win32 qui est une API en C.
Les exemples en C++ ne doivent pas vraiment être en C++ mais en C+ (joke -)).
Donnez-nous l'URL d'un exemple en C++ et on verra si cela n'est pas déjà du C.

[Invité]

Voici l'exemple du MSDN

[bacelar]

Effectivement, COM obscurcie un peu les choses.
A l’arrache, le code C devrait ressembler à cela :

Code :

Sélectionner tout - Visualiser dans une fenêtre à part

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#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#include <Wbemidl.h>
#include <WbemCli.h>
#include <wincred.h>

int _tmain(int argc, _TCHAR* argv[])
{
	HRESULT hres;
	IWbemLocator *pLoc = NULL;
	IWbemServices *pSvc = NULL;
	IEnumWbemClassObject* pEnumerator = NULL;	 
    IWbemClassObject *pclsObj;
    ULONG uReturn = 0;
	VARIANT vtProp;
	BSTR cimv2 = L"\\\\computerName\\root\\cimv2";
	BSTR Locale = L"MS_409";
    BSTR Authority = L"ntlmdomain:domain";
	BSTR WQL = L"WQL";
	BSTR Select = L"Select * from Win32_OperatingSystem";

	// Get the user name and password for the remote computer
    CREDUI_INFO cui;
    TCHAR pszName[CREDUI_MAX_USERNAME_LENGTH+1];
    TCHAR pszPwd[CREDUI_MAX_PASSWORD_LENGTH+1];
    BOOL fSave;
    DWORD dwErr;

    // 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 --------------------------
    // Note: If you are using Windows 2000, you need to specify -
    // the default authentication credentials for a user by using
    // a SOLE_AUTHENTICATION_LIST structure in the pAuthList ----
    // parameter of CoInitializeSecurity ------------------------

    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 -------------------------

    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

    cui.cbSize = sizeof(CREDUI_INFO);
    cui.hwndParent = NULL;
    // Ensure that MessageText and CaptionText identify
    // what credentials to use and which application requires them.
    cui.pszMessageText = TEXT("Remote computer account information");
    cui.pszCaptionText = TEXT("Enter Account Information");
    cui.hbmBanner = NULL;
    fSave = FALSE;

    dwErr = CredUIPromptForCredentials( 
        &cui,                             // CREDUI_INFO structure
        TEXT(""),                         // Target for credentials
        NULL,                             // Reserved
        0,                                // Reason
        pszName,                          // User name
        CREDUI_MAX_USERNAME_LENGTH+1,     // Max number for user name
        pszPwd,                           // Password
        CREDUI_MAX_PASSWORD_LENGTH+1,     // Max number for password
        &fSave,                           // State of save check box
        CREDUI_FLAGS_GENERIC_CREDENTIALS |  // flags
        CREDUI_FLAGS_ALWAYS_SHOW_UI |
        CREDUI_FLAGS_DO_NOT_PERSIST);  

    if(dwErr)
    {
        /*cout << "Did not get credentials." << endl;*/
        pLoc->lpVtbl->Release(pLoc);     
        CoUninitialize();
        return 1;      
    }

    // Connect to the remote root\cimv2 namespace
    // and obtain pointer pSvc to make IWbemServices calls.
    //---------------------------------------------------------
    // change the computerName and domain 
    // strings below to the full computer name and domain 
    // of the remote computer

    hres = pLoc->lpVtbl->ConnectServer(pLoc,
        cimv2,
        pszName,                 // User name
        pszPwd,                  // User password
        Locale,               // Locale             
        NULL,                             // Security flags
        Authority,    // Authority        
        0,                                // Context object 
        &pSvc                             // IWbemServices proxy
        );

    // When you have finished using the credentials,
    // erase them from memory.
    SecureZeroMemory(pszName, sizeof(pszName));
    SecureZeroMemory(pszPwd, sizeof(pszPwd));
    
    if (FAILED(hres))
    {
        /*cout << "Could not connect. Error code = 0x" 
             << hex << hres << endl;*/
        pLoc->lpVtbl->Release(pLoc);     
        CoUninitialize();
        return 1;                // Program has failed.
    }

   /* cout << "Connected to ROOT\\CIMV2 WMI namespace" << endl;*/


    // Step 5: --------------------------------------------------
    // Set security levels on a WMI connection ------------------

    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->lpVtbl->Release(pSvc);
        pLoc->lpVtbl->Release(pLoc);     
        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
    hres = pSvc->lpVtbl->ExecQuery(pSvc,
        WQL, 
        Select,
        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->lpVtbl->Release(pSvc);
        pLoc->lpVtbl->Release(pLoc);
        CoUninitialize();
        return 1;               // Program has failed.
    }

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

        if(0 == uReturn)
        {
            break;
        }

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

        // Get the value of the FreePhysicalMemory property
        hr = pclsObj->lpVtbl->Get(pclsObj,L"FreePhysicalMemory",
            0, &vtProp, 0, 0);
        /*wcout << " Free physical memory (in kilobytes): "
            << vtProp.uintVal << endl;*/
        VariantClear(&vtProp);
    }

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

    return 0;   // Program successfully completed.

}

[Invité]

Donc j'en déduis que ça doit être faisable en C.
Merci beaucoup pour ta réponse, ça me donne un bon point de départ.