Creating a Service Connection Point

The following code example shows how to create and initialize a service connection point. The code example performs additional steps that enable the service to update the SCP values at run time. Typically, a service installer performs these steps as part of installing a service instance on a host computer.

This code example creates the SCP object as a child object for the object of the local computer. It uses the GetComputerObjectName function to get the DN of the local computer object. It then uses the DN to bind to an IDirectoryObject pointer for the computer object. The IDirectoryObject::CreateDSObject method creates the SCP and specifies initial values for the important SCP attributes.

CreateDSObject returns a pointer to the new SCP, which the code example uses to retrieve an IADs pointer for the SCP. The code example uses IADs methods to retrieve the objectGUID and distinguishedName attributes of the SCP. The code example uses the objectGUID to compose a string used to bind to the SCP, and then caches the GUID binding string in the local registry where it can be retrieved by the service at run time. The distinguishedName is returned to the function caller for use in composing a service principal name (SPN) for the service instance.

The following code example calls this function as part of the basic steps of installing a directory-enabled service. For more information, see Installing a Service on a Host Computer.


// ScpCreate
//
// Create a new service connection point as a child object of the 
// local server computer object.
//
DWORD
ScpCreate(
       USHORT usPort, // Service's default port to store in SCP.
       LPTSTR szClass, // Service class string to store in SCP.
       LPTSTR szAccount, // Logon account that must access SCP.
       UINT ccDN, // Length of the pszDN buffer in characters
       TCHAR *pszDN) // Returns distinguished name of SCP.
{
DWORD dwStat, dwAttr, dwLen;
HRESULT hr;
IDispatch *pDisp;          // Returned dispinterface of new object.
IDirectoryObject *pComp;   // Computer object; parent of SCP.
IADs *pIADsSCP;            // IADs interface on new object.

if(!szClass || !szAccount || !pszDN || !(ccDN > 0))
{
       hr = ERROR_INVALID_PARAMETER;
       ReportError(TEXT("Invalid parameter."), hr);
       return hr;
}

// Values for SCPs keywords attribute.
TCHAR* KwVal[]={
        TEXT("83C29870-1DFC-11d3-A193-0000F87A9099"), // Vendor GUID.
        TEXT("A762885A-AA44-11d2-81F1-00C04FB9624E"), // Product GUID.
        TEXT("Microsoft"), // Vendor Name.
        TEXT("Windows 2000 Auth-O-Matic"), // Product Name.
};

TCHAR       szServer[MAX_PATH];
TCHAR       szDn[MAX_PATH];
TCHAR       szAdsPath[MAX_PATH];
TCHAR       szPort[6];

HKEY        hReg;
DWORD       dwDisp;

ADSVALUE cn,objclass,keywords[4],binding,classname,dnsname,nametype;

// SCP attributes to set during creation of SCP.
ADS_ATTR_INFO   ScpAttribs[] = 
{
    {
        TEXT("cn"),
        ADS_ATTR_UPDATE,
        ADSTYPE_CASE_IGNORE_STRING,
        &cn,
        1
    },
    {
        TEXT("objectClass"),
        ADS_ATTR_UPDATE,
        ADSTYPE_CASE_IGNORE_STRING,
        &objclass,
        1
    },
    {
         TEXT("keywords"),
         ADS_ATTR_UPDATE,
         ADSTYPE_CASE_IGNORE_STRING,
         keywords,
         4
    },
    {
         TEXT("serviceDnsName"),
         ADS_ATTR_UPDATE,
         ADSTYPE_CASE_IGNORE_STRING,
         &dnsname,
         1
    },
    {
        TEXT("serviceDnsNameType"),
        ADS_ATTR_UPDATE,
        ADSTYPE_CASE_IGNORE_STRING,
        &nametype,
        1
    },
    {
        TEXT("serviceClassName"),
        ADS_ATTR_UPDATE,
        ADSTYPE_CASE_IGNORE_STRING,
        &classname,
        1
    },
    {
        TEXT("serviceBindingInformation"),
        ADS_ATTR_UPDATE,
        ADSTYPE_CASE_IGNORE_STRING,
        &binding,
        1
    },
};

BSTR bstrGuid = NULL;
TCHAR pwszBindByGuidStr[1024]; 
VARIANT var;

// Get the DNS name of the local computer.
dwLen = sizeof(szServer);
if (!GetComputerNameEx(ComputerNameDnsFullyQualified,szServer,&dwLen))
    return GetLastError();
_tprintf(TEXT("GetComputerNameEx: %s\n"), szServer);
    
// Enter the attribute values to be stored in the SCP.
keywords[0].dwType = ADSTYPE_CASE_IGNORE_STRING;
keywords[1].dwType = ADSTYPE_CASE_IGNORE_STRING;
keywords[2].dwType = ADSTYPE_CASE_IGNORE_STRING;
keywords[3].dwType = ADSTYPE_CASE_IGNORE_STRING;

keywords[0].CaseIgnoreString=KwVal[0];
keywords[1].CaseIgnoreString=KwVal[1];
keywords[2].CaseIgnoreString=KwVal[2];
keywords[3].CaseIgnoreString=KwVal[3];

cn.dwType                   = ADSTYPE_CASE_IGNORE_STRING;
cn.CaseIgnoreString         = TEXT("SockAuthAD");
objclass.dwType             = ADSTYPE_CASE_IGNORE_STRING;
objclass.CaseIgnoreString   = TEXT("serviceConnectionPoint");

dnsname.dwType              = ADSTYPE_CASE_IGNORE_STRING;
dnsname.CaseIgnoreString    = szServer;
classname.dwType            = ADSTYPE_CASE_IGNORE_STRING;
classname.CaseIgnoreString  = szClass;

_stprintf_s(szPort,TEXT("%d"),usPort);
binding.dwType              = ADSTYPE_CASE_IGNORE_STRING;
binding.CaseIgnoreString    = szPort;
nametype.dwType             = ADSTYPE_CASE_IGNORE_STRING;
nametype.CaseIgnoreString   = TEXT("A");

/*
Get the distinguished name of the computer object for the local 
computer.
*/
dwLen = sizeof(szDn);
if (!GetComputerObjectName(NameFullyQualifiedDN,szDn,&dwLen))
    return GetLastError();
_tprintf(TEXT("GetComputerObjectName: %s\n"), szDn);

/*
Compose the ADSpath and bind to the computer object for the local 
computer.
*/
_tcsncpy_s(szAdsPath,TEXT("LDAP://"),MAX_PATH);
_tcsncat_s(szAdsPath,szDn,MAX_PATH - _tcslen(szAdsPath));
hr = ADsGetObject(szAdsPath, IID_IDirectoryObject, (void **)&pComp);
if (FAILED(hr)) {
    ReportError(TEXT("Failed to bind Computer Object."),hr);
    return hr;
}

//*******************************************************************
// Publish the SCP as a child of the computer object
//*******************************************************************

// Calculate attribute count.
dwAttr = sizeof(ScpAttribs)/sizeof(ADS_ATTR_INFO);  

// Complete the action.
hr = pComp->CreateDSObject(TEXT("cn=SockAuthAD"),
                           ScpAttribs, dwAttr, &pDisp);
if (FAILED(hr)) {
    ReportError(TEXT("Failed to create SCP:"), hr);
    pComp -> Release();
    return hr;
}

pComp -> Release();

// Query for an IADs pointer on the SCP object.
hr = pDisp->QueryInterface(IID_IADs,(void **)&pIADsSCP);
if (FAILED(hr)) {
    ReportError(TEXT("Failed to QueryInterface for IADs:"),hr);
    pDisp->Release();
    return hr;
}
pDisp->Release();

// Set ACEs on the SCP so a service can modify it.
hr = AllowAccessToScpProperties(
        szAccount,     // Service account to allow access.
        pIADsSCP);     // IADs pointer to the SCP object.
if (FAILED(hr)) {
    ReportError(TEXT("Failed to set ACEs on SCP DACL:"), hr);
    return hr;
}

// Get the distinguished name of the SCP.
VariantInit(&var); 
hr = pIADsSCP->Get(CComBSTR("distinguishedName"), &var); 
if (FAILED(hr)) {
    ReportError(TEXT("Failed to get distinguishedName:"), hr);
    pIADsSCP->Release();
    return hr;
}
_tprintf(TEXT("distinguishedName via IADs: %s\n"), var.bstrVal);

// Return the DN of the SCP, which is used to compose the SPN.
// The best practice is to either accept and return the buffer
// size or do this in a _try / _except block, both omitted here
// for clarity.
_tcsncpy_s(pszDN, var.bstrVal, ccDN);

// Retrieve the SCP objectGUID in format suitable for binding. 
hr = pIADsSCP->get_GUID(&bstrGuid); 
if (FAILED(hr)) {
    ReportError(TEXT("Failed to get GUID:"), hr);
    pIADsSCP->Release();
    return hr;
}

// Build a string for binding to the object by GUID.
_tcsncpy_s(pwszBindByGuidStr, 
    TEXT("LDAP://<GUID="),
    1024);
_tcsncat_s(pwszBindByGuidStr, 
    bstrGuid, 
    1024 -_tcslen(pwszBindByGuidStr));
_tcsncat_s(pwszBindByGuidStr, 
    TEXT(">"), 
    1024 -_tcslen(pwszBindByGuidStr));
_tprintf(TEXT("GUID binding string: %s\n"), 
    pwszBindByGuidStr);

pIADsSCP->Release();

// Create a registry key under 
// HKEY_LOCAL_MACHINE\SOFTWARE\Vendor\Product.
dwStat = RegCreateKeyEx(HKEY_LOCAL_MACHINE,
            TEXT("Software\\Fabrikam\\Auth-O-Matic"),
            0,
            NULL,
            REG_OPTION_NON_VOLATILE,
            KEY_ALL_ACCESS,
            NULL,
            &hReg,
            &dwDisp);
if (dwStat != NO_ERROR) {
    ReportError(TEXT("RegCreateKeyEx failed:"), dwStat);
    return dwStat;
}

// Cache the GUID binding string under the registry key.
dwStat = RegSetValueEx(hReg, TEXT("GUIDBindingString"), 0, REG_SZ,
                           (const BYTE *)pwszBindByGuidStr, 
                           2*(_tcslen(pwszBindByGuidStr)));
if (dwStat != NO_ERROR) {
    ReportError(TEXT("RegSetValueEx failed:"), dwStat);
    return dwStat;
}

RegCloseKey(hReg);

// Cleanup should delete the SCP and registry key if an error occurs.

return dwStat;
}

 

 

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