Windows services installation / uninstallation in Windows 10 - c++

Question

I have an application, in C++, which attempts, upon running (at which time, no other relevant process is thought to be running), to install a couple of services.
The workflow is that if the services exist, then they are uninstalled, else they and uninstalled and then re-installed.
I had followed a few tutorials like :
Installing a service
Unfortunately, something seems to go wrong with the installation or the uninstallation.
Upon assuming that the service is not installed, when I proceed to install the services, they get installed, and I then attempt to change the configuration, to delayed-Auto start.
At this stage, although the services are installed, I cannot start them, as I get the error saying services cannot be found.
When I try uninstalling the services, the uninstallation fails, giving an error 1060, saying the services are marked for deletion.
SC_HANDLE schSCManager;
SC_HANDLE schService;
schSCManager = OpenSCManager(
NULL, // local computer
NULL, // ServicesActive database
SC_MANAGER_ALL_ACCESS); // full access rights
if (schSCManager == nullptr)
{
continue;
}
if (bInstall)
{
schService = CreateService(
schSCManager, // SCM database
szServiceName, // name of service
szDisplayName, // service name to display
SERVICE_ALL_ACCESS, // desired access
SERVICE_WIN32_OWN_PROCESS, // service type
SERVICE_DEMAND_START, // start type
SERVICE_ERROR_NORMAL, // error control type
szDirectory, // path to service's binary
NULL, // no load ordering group
NULL, // no tag identifier
NULL, // no dependencies
NULL, // LocalSystem account
NULL); // no password
if (schService == NULL)
{
TraceAdvice(L"CreateService failed (%d)\n", GetLastError());
CloseServiceHandle(schSCManager);
continue;
}
else
{
if (!ChangeServiceConfig(
schService, // handle of service
SERVICE_NO_CHANGE, // service type: no change
SERVICE_CONFIG_DELAYED_AUTO_START_INFO, // service start type
SERVICE_NO_CHANGE, // error control: no change
NULL, // binary path: no change
NULL, // load order group: no change
NULL, // tag ID: no change
NULL, // dependencies: no change
NULL, // account name: no change
NULL, // password: no change
NULL)) // display name: no change
{
TraceAdvice(L"ChangeServiceConfig failed (%d)\n", GetLastError());
}
TraceAdvice(L"Service installed successfully\n");
}
CloseServiceHandle(schService);
CloseServiceHandle(schSCManager);
/*TraceFatal(_T("Now installing : %s"), szServiceName);
_stprintf_s(szTmp, _T("SC create %s binpath= \"%s%s.exe\" displayName= \"%s\" start= delayed-auto"), szServiceName, szDirectory, szServiceName, szDisplayName);
TraceFatal(_T("Command is : %s"), szTmp);*/
}
else
{
_wsystem(_T("taskkill /F /IM mmc.exe")); // Need to kill any instance of MMC running
_wsystem(_T("taskkill /F /IM procexp.exe"));
schService = OpenService(
schSCManager, // SCM database
szServiceName, // name of service
DELETE); // need delete access
if (schService == NULL)
{
TraceAdvice(L"OpenService failed (%d)\n", GetLastError());
CloseServiceHandle(schSCManager);
continue;
}
DWORD dwBytesNeeded;
SERVICE_STATUS_PROCESS ssp;
if (!QueryServiceStatusEx(
schService,
SC_STATUS_PROCESS_INFO,
(LPBYTE)&ssp,
sizeof(SERVICE_STATUS_PROCESS),
&dwBytesNeeded))
{
printf("QueryServiceStatusEx failed (%d)\n", GetLastError());
}
if (ssp.dwCurrentState == SERVICE_RUNNING)
{
_stprintf_s(szTmp, _T("taskkill /F /IM %s.exe"), szServiceName);
_wsystem(szTmp);
}
// Delete the service.
if (!DeleteService(schService))
{
TraceAdvice(L"DeleteService failed (%d)\n", GetLastError());
}
else TraceAdvice(L"Service deleted successfully\n");
CloseServiceHandle(schService);
CloseServiceHandle(schSCManager);
}
}
I made sure of all the points, viz.
Task manager was closed
Service console was closed.
All instances of MMC were closed.
Service was stopped
Service was not open in debugger in Visual Studio...
But it does not avail. The service does not get uninstalled till I reboot the system (deleting the registry linked to the service does not work either).
I have checked the parameters I pass on to these functions, and they seem correct.
What else should I be checking for, to ensure a correct installation, or a successful uninstallation?

Answer 1

You need to stop the service first, otherwise it gets stuck in this pending delete state. Forcibly killing the service is not the same thing as stopping it. From the same area of documentation, you need to ControlService(SERVICE_CONTROL_STOP).