Directory Services

Installing a Service on a Host Computer

The following code example shows the basic steps of installing a directory-enabled service on a host computer. It performs the following operations:

This code example works correctly regardless of whether the logon account is a local or domain user account or the LocalSystem account. For a domain user account, the szServiceAccountSAM parameter contains the domain\username name of the account, and the szServiceAccountDN parameter contains the distinguished name of the user account object in the directory. For the LocalSystem account, szServiceAccountSAM and szPassword are NULL, and szServiceAccountSN is the distinguished name of the local computer's account object in the directory. If szServiceAccountSAM specifies a local user account (name format is ".\username"), the code example skips the SPN registration because mutual authentication is not supported for local user accounts.

Be aware that the default security configuration allows only domain administrators to execute this code.

Also, be aware that this code example, as written, must be executed on the computer where the service is being installed. Consequently, it is typically in a separate installation executable from your service installation code, if any, that extends the schema, extends the UI, or sets up group policy. Those operations install service components for an entire a forest, whereas this code installs the service on a single computer.

void InstallServiceOnLocalComputer(
			LPTSTR szServiceAccountDN,  // Distinguished name of logon account.
			LPTSTR szServiceAccountSAM, // SAM name of logon account.
			LPTSTR szPassword)		// Password of logon account.
SC_HANDLE   schService = NULL;
SC_HANDLE   schSCManager = NULL;
TCHAR szPath[512];
LPTSTR lpFilePart;
TCHAR szServiceClass[]=TEXT("ADSockAuth");
DWORD dwStatus;
TCHAR **pspn=NULL;
ULONG ulSpn=1;
// Get the full path of the service's executable.
// The code example assumes that the executable is in the current directory.
dwStatus = GetFullPathName(TEXT("service.exe"), 512, szPath, &lpFilePart);
if (dwStatus == 0) {
	_tprintf(TEXT("Unable to install %s - %s\n"), 
			TEXT(SZSERVICEDISPLAYNAME), GetLastErrorText(szErr, 256));
_tprintf(TEXT("path of service.exe: %s\n"), szPath);
// Open the Service Control Manager on the local computer.
schSCManager = OpenSCManager(
				NULL, 			 // Computer (NULL == local)
				NULL, 			 // Database (NULL == default)
				SC_MANAGER_ALL_ACCESS   // Access required
if (! schSCManager) {
	_tprintf(TEXT("OpenSCManager failed - %s\n"), 
	goto cleanup;
// Install the service in the SCM database.
schService = CreateService(
			schSCManager, 		 // SCManager database
			TEXT(SZSERVICENAME), 	// Name of service
			SERVICE_ALL_ACCESS, 	 // Desired access
			SERVICE_WIN32_OWN_PROCESS,  // Service type
			SERVICE_DEMAND_START,  // Start type
			SERVICE_ERROR_NORMAL,  // Error control type
			szPath, 				 // Service binary
			NULL, 				 // No load ordering group
			NULL, 				 // No tag identifier
			TEXT(SZDEPENDENCIES),  // Dependencies
			szServiceAccountSAM, 	// Service account
			szPassword); 			// Account password
if (! schService) {
	_tprintf(TEXT("CreateService failed - %s\n"), 
	goto cleanup;
_tprintf(TEXT("%s installed.\n"), TEXT(SZSERVICEDISPLAYNAME) );
// Create the service's Service Connection Point (SCP).
dwStatus = ScpCreate(
		2000, 			 // Service default port number
		szServiceClass,  // Specifies the service class string
		szServiceAccountSAM,  // SAM name of logon account for ACE
		szDNofSCP			 // Buffer returns the DN of the SCP
if (dwStatus != 0) {
	_tprintf(TEXT("ScpCreate failed: %d\n"), dwStatus );
	goto cleanup;
// Compose and register a service principal name for this service.
// This is performed on the install path because this requires elevated
// privileges for updating the directory.
// If a local account of the format ".\username", skip the SPN.
if ( szServiceAccountSAM[0] == '.' ) 
	_tprintf(TEXT("Do not register SPN for a local account.\n"));
	goto cleanup;
dwStatus = SpnCompose(
		&pspn, 		// Receives pointer to the SPN array.
		&ulSpn, 	 // Receives number of SPNs returned.
		szDNofSCP, 	// Input: DN of the SCP.
		szServiceClass);  // Input: the service's class string.
if (dwStatus == NO_ERROR) 
	dwStatus = SpnRegister(
		szServiceAccountDN,  // Account on which SPNs are registered.
		pspn, 			// Array of SPNs to register.
		ulSpn, 		 // Number of SPNs in array.
		DS_SPN_ADD_SPN_OP);  // Operation code: Add SPNs.
if (dwStatus != NO_ERROR) 
	_tprintf(TEXT("Failed to compose SPN: Error was %X\n"), 
	ScpDelete(szDNofSCP, szServiceClass, szServiceAccountDN);
	goto cleanup;
if (schSCManager)
if (schService)
DsFreeSpnArray(ulSpn, pspn);

For more information about the previous code example, see Composing the SPNs for a Service with an SCP and Registering the SPNs for a Service.