Querying a Service's Configuration Example
A service configuration program uses the OpenService() function to get a handle with SERVICE_QUERY_CONFIG access to an installed service object. The program can then use the service object handle in the QueryServiceConfig() and QueryServiceConfig2() functions to retrieve the current configuration of the service.
In the following code fragment example, the DoQuerySvc() function uses QueryServiceConfig() and QueryServiceConfig2() to retrieve configuration information, then writes selected information to the console. The szSvcName variable is a global variable that contains the name of the service.
// Purpose: Retrieves and displays the current service configuration.
// Parameters: None
// Return value: None
void __stdcall DoQuerySvc(void)
{
SC_HANDLE schSCManager;
SC_HANDLE schService;
LPQUERY_SERVICE_CONFIG lpsc;
LPSERVICE_DESCRIPTION lpsd;
DWORD dwBytesNeeded, cbBufSize, dwError;
// Get a handle to the SCM database
schSCManager = OpenSCManager(
NULL, // local computer
NULL, // ServicesActive database
SC_MANAGER_ALL_ACCESS); // full access rights
if (schSCManager == NULL)
{
wprintf(L"OpenSCManager() failed, error %u\n", GetLastError());
return;
}
else
wprintf(L"OpenSCManager() is working!\n");
// Get a handle to the service
schService = OpenService(
schSCManager, // SCM database
szSvcName, // name of service
SERVICE_QUERY_CONFIG); // need query config access
if (schService == NULL)
{
wprintf(L"OpenService() failed, error %u\n", GetLastError());
CloseServiceHandle(schSCManager);
return;
}
else
wprintf(L"OpenService() is OK!\n");
// Get the configuration information
if(!QueryServiceConfig(schService, NULL, 0, &dwBytesNeeded))
{
dwError = GetLastError();
if(ERROR_INSUFFICIENT_BUFFER == dwError)
{
cbBufSize = dwBytesNeeded;
lpsc = (LPQUERY_SERVICE_CONFIG) LocalAlloc(LMEM_FIXED, cbBufSize);
}
else
{
wprintf(L"QueryServiceConfig() failed, error %u\n", dwError);
goto cleanup;
}
}
if( !QueryServiceConfig(schService,lpsc,cbBufSize,&dwBytesNeeded))
{
wprintf(L"QueryServiceConfig() failed, error %u\n", GetLastError());
goto cleanup;
}
if( !QueryServiceConfig2(schService,SERVICE_CONFIG_DESCRIPTION,NULL,0,&dwBytesNeeded))
{
dwError = GetLastError();
if(ERROR_INSUFFICIENT_BUFFER == dwError)
{
cbBufSize = dwBytesNeeded;
lpsd = (LPSERVICE_DESCRIPTION)LocalAlloc(LMEM_FIXED, cbBufSize);
}
else
{
wprintf(L"QueryServiceConfig2() failed, error %u\n", dwError);
goto cleanup;
}
}
if (!QueryServiceConfig2(schService,SERVICE_CONFIG_DESCRIPTION,(LPBYTE) lpsd,cbBufSize,&dwBytesNeeded))
{
wprintf(L"QueryServiceConfig2() failed, error %u\n", GetLastError());
goto cleanup;
}
// Print the configuration information
wprintf(L"%s configuration: \n", szSvcName);
wprintf(L" Type: 0x%x\n", lpsc->dwServiceType);
wprintf(L" Start Type: 0x%x\n", lpsc->dwStartType);
wprintf(L" Error Control: 0x%x\n", lpsc->dwErrorControl);
wprintf(L" Binary path: %s\n", lpsc->lpBinaryPathName);
wprintf(L" Account: %s\n", lpsc->lpServiceStartName);
if (lpsd->lpDescription != NULL && lstrcmp(lpsd->lpDescription, L"") != 0)
wprintf(L" Description: %s\n", lpsd->lpDescription);
if (lpsc->lpLoadOrderGroup != NULL && lstrcmp(lpsc->lpLoadOrderGroup, L"") != 0)
wprintf(L" Load order group: %s\n", lpsc->lpLoadOrderGroup);
if (lpsc->dwTagId != 0)
wprintf(L" Tag ID: %d\n", lpsc->dwTagId);
if (lpsc->lpDependencies != NULL && lstrcmp(lpsc->lpDependencies, L"") != 0)
wprintf(L" Dependencies: %s\n", lpsc->lpDependencies);
LocalFree(lpsc);
LocalFree(lpsd);
cleanup:
CloseServiceHandle(schService);
CloseServiceHandle(schSCManager);
}