COM for a WMI Application

http://technet.microsoft.com/zh-cn/library/aa390421

1  Initialize COM parameters with a call to CoInitializeEx  

2  Initialize COM process security  by calling CoInitializeSecurity

3 Obtain the initial locator to WMI by calling CoCreateInstance

4 Obtain a pointer to IWbemServices for the root\cimv2 namespace on the local computer by calling IWbemLocator::ConnectServer.

5 Set IWbemServices proxy security so the WMI service can impersonate the client by calling CoSetProxyBlanket.

6 Use the IWbemServices pointer to make requests to WMI.

 

#define _WIN32_DCOM

#include <iostream>

using namespace std;

#include <wbemidl.h>

#include <windows.h>

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

 

HRESULT hr;

hr = CoInitializeEx(0, COINIT_MULTITHREADED);

 if (FAILED(hr))

{ cout << "Failed to initialize COM library. Error code = 0x"       << hex << hr << endl;   return hr;}

//Set the general COM security levels

hr =  CoInitializeSecurity(    NULL,                      // Security descriptor       

-1,                        // COM negotiates authentication service   

 NULL,                      // Authentication services   

 NULL,                      // Reserved   

 RPC_C_AUTHN_LEVEL_DEFAULT, // Default authentication level for proxies   

 RPC_C_IMP_LEVEL_IMPERSONATE, // Default Impersonation level for proxies   

NULL,                        // Authentication info   

EOAC_NONE,                   // Additional capabilities of the client or server   

NULL);                       // Reserved

if (FAILED(hr)){   cout << "Failed to initialize security. Error code = 0x"         << hex << hr << endl;   CoUninitialize();   return hr;    // Program has failed.}

 

IWbemLocator *pLoc = 0;   

HRESULT hr;    hr = CoCreateInstance(CLSID_WbemLocator, 0,        

CLSCTX_INPROC_SERVER,

 IID_IWbemLocator,

(LPVOID *) &pLoc);    

 if (FAILED(hr)) { cout << "Failed to create IWbemLocator object. Err code = 0x" << hex << hr << endl;  CoUninitialize(); return hr;     // Program has failed.    }

 

IWbemServices *pSvc = 0;    // Connect to the root\default namespace with the current user.   

hr = pLoc->ConnectServer( BSTR(L"ROOT\\DEFAULT"),  NULL, NULL, 0, NULL, 0, 0, &pSvc);   

 if (FAILED(hr)) { cout << "Could not connect. Error code = 0x"  << hex << hr << endl;   pLoc->Release();   CoUninitialize();    return hr;   // Program has failed.    }   

 cout << "Connected to WMI" << endl;

 

HRESULT hres;   

 IWbemServices *pSvc = 0;   

 IWbemLocator *pLoc = 0;    // Set the proxy so that impersonation of the client occurs.   

hres = CoSetProxyBlanket(pSvc, RPC_C_AUTHN_WINNT,  RPC_C_AUTHZ_NONE, NULL, RPC_C_AUTHN_LEVEL_CALL, RPC_C_IMP_LEVEL_IMPERSONATE,       NULL,       EOAC_NONE    );   

 if (FAILED(hres)) 

{  cout << "Could not set proxy blanket. Error code = 0x"  << hex << hres << endl; 

 pSvc->Release();  pLoc->Release();  CoUninitialize();  return hres;      // Program has failed.    }

 

// Set up to call the Win32_Process::Create method

BSTR MethodName = SysAllocString(L"Create");

BSTR ClassName = SysAllocString(L"Win32_Process");

IWbemClassObject* pClass = NULL;

hres = pSvc->GetObject(ClassName, 0, NULL, &pClass, NULL);

IWbemClassObject* pInParamsDefinition = NULL;

hres = pClass->GetMethod(MethodName, 0,     &pInParamsDefinition, NULL);

IWbemClassObject* pClassInstance = NULL;

hres = pInParamsDefinition->SpawnInstance(0, &pClassInstance);// Create the values for the in-parameters

VARIANT varCommand;

varCommand.vt = VT_BSTR;

varCommand.bstrVal = L"notepad.exe";// Store the value for the in-parameters

hres = pClassInstance->Put(L"CommandLine", 0,    &varCommand, 0);wprintf(L"The command is: %s\n", V_BSTR(&varCommand));

 

//------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//

#define _WIN32_DCOM

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

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

int main(int iArgCnt, 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 --------------------------
    // Note: If you are using Windows 2000, you must 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 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;
        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 local root\cimv2 namespace
    // and obtain pointer pSvc to make IWbemServices calls.
    hres = pLoc->ConnectServer(
        _bstr_t(L"ROOT\\CIMV2"), 
        NULL,
        NULL, 
        0, 
        NULL, 
        0, 
        0, 
        &pSvc
    );
	    
    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\\CIMV2 WMI namespace" << endl;


    // Step 5: --------------------------------------------------
    // Set security levels for 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 ----

    // set up to call the Win32_Process::Create method
    BSTR MethodName = SysAllocString(L"Create");
    BSTR ClassName = SysAllocString(L"Win32_Process");

    IWbemClassObject* pClass = NULL;
    hres = pSvc->GetObject(ClassName, 0, NULL, &pClass, NULL);

    IWbemClassObject* pInParamsDefinition = NULL;
    hres = pClass->GetMethod(MethodName, 0, 
        &pInParamsDefinition, NULL);

    IWbemClassObject* pClassInstance = NULL;
    hres = pInParamsDefinition->SpawnInstance(0, &pClassInstance);

    // Create the values for the in parameters
    VARIANT varCommand;
    varCommand.vt = VT_BSTR;
    varCommand.bstrVal = L"notepad.exe";

    // Store the value for the in parameters
    hres = pClassInstance->Put(L"CommandLine", 0,
        &varCommand, 0);
    wprintf(L"The command is: %s\n", V_BSTR(&varCommand));

    // Execute Method
    IWbemClassObject* pOutParams = NULL;
    hres = pSvc->ExecMethod(ClassName, MethodName, 0,
    NULL, pClassInstance, &pOutParams, NULL);

    if (FAILED(hres))
    {
        cout << "Could not execute method. Error code = 0x" 
             << hex << hres << endl;
        VariantClear(&varCommand);
        SysFreeString(ClassName);
        SysFreeString(MethodName);
        pClass->Release();
        pInParamsDefinition->Release();
        pOutParams->Release();
        pSvc->Release();
        pLoc->Release();     
        CoUninitialize();
        return 1;               // Program has failed.
    }

    // To see what the method returned,
    // use the following code.  The return value will
    // be in &varReturnValue
    VARIANT varReturnValue;
    hres = pOutParams->Get(_bstr_t(L"ReturnValue"), 0, 
        &varReturnValue, NULL, 0);


    // Clean up
    //--------------------------
    VariantClear(&varCommand);
    VariantClear(&varReturnValue);
    SysFreeString(ClassName);
    SysFreeString(MethodName);
    pClass->Release();
    pInParamsDefinition->Release();
    pOutParams->Release();
    pLoc->Release();
    pSvc->Release();
    CoUninitialize();
    return 0;
}