c++ restart service in windows as admin - c++

Question

I'm trying to restart the "postgres" service in my C++ application on windows 10 but I having some problems with access rights( my guess ). I have tried running the code as a domain user that has local admin rights and as a local administrator but none of these seem to work. I can restart the service manually via the services.msc. The code fails already at OpenSCManager which returns NULL. I have also tried other access rights but then OpenService fails. This is my code
auto showError = []()
{
std::ostringstream os;
os << GetLastError();
qDebug() << "Restart PostgreSQL service failed : " << QString::fromStdString( os.str());
};
SERVICE_STATUS Status;
SC_HANDLE SCManager = OpenSCManager(NULL, SERVICES_ACTIVE_DATABASE, SC_MANAGER_ALL_ACCESS );
if(SCManager == NULL)
showError();
SC_HANDLE SHandle = OpenService(SCManager, L"postgres", SERVICE_ALL_ACCESS );
if(SHandle == NULL)
showError();
if(!ControlService(SHandle, SERVICE_CONTROL_STOP, &Status))
showError();
do
{
QueryServiceStatus(SHandle, &Status);
qDebug() << "Checking Service Status...\n";
}while(Status.dwCurrentState != SERVICE_STOPPED);
if(!StartService(SHandle, 0, NULL))
showError();
std::cin.sync();
std::cin.ignore();
CloseServiceHandle(SCManager);
CloseServiceHandle(SHandle);

Answer 1

You are asking for too many permissions that you don't actually need. Don't use SC_MANAGER_ALL_ACCESS and SERVICE_ALL_ACCESS. NEVER ask for more permissions than you really need. All you really need in this situation are SC_MANAGER_CONNECT for OpenSCManager(), and SERVICE_STOP, SERVICE_START and SERVICE_QUERY_STATUS for OpenService().
If you still get an "Access Denied" error after fixing this in your code, then the service really requires your account to have permissions to start/stop the service. So either run your code in an elevated admin process, or at least configure your user account with the appropriate permissions.
And FYI, your query loop is too minimalistic. You are ignoring the Status that ControlService() reports, and you are not accounting for the possibility of the service entering a pending state, or refusing to stop. You need to check the initial status, only if it is in a pending state than enter the query loop until it is no longer in a pending state, then check the final state for stopped before then attempting to start the service. Also be sure to check if the service hangs while trying to stop it.
See Stopping a Service on MSDN.
Try something more like this:
auto showError = []()
{
DWORD err = GetLastError();
qDebug() << "Restart PostgreSQL service failed. Error: " << err << "\n";
};
SERVICE_STATUS Status;
SC_HANDLE SCManager = OpenSCManager(NULL, NULL, SC_MANAGER_CONNECT);
if (!SCManager)
{
showError();
return;
}
SC_HANDLE SHandle = OpenService(SCManager, L"postgres", SERVICE_STOP | SERVICE_START | SERVICE_QUERY_STATUS);
if (!SHandle)
{
showError();
CloseServiceHandle(SCManager);
return;
}
if (!QueryServiceStatus(SHandle, &Status))
{
showError();
CloseServiceHandle(SHandle);
CloseServiceHandle(SCManager);
return;
}
if (Status.dwCurrentState != SERVICE_STOPPED)
{
qDebug() << "Stopping PostgreSQL service...\n";
if (!ControlService(SHandle, SERVICE_CONTROL_STOP, &Status))
{
showError();
CloseServiceHandle(SHandle);
CloseServiceHandle(SCManager);
return;
}
DWORD dwStartTime = GetTickCount();
DWORD dwTimeout = 30000; // 30-second time-out
DWORD dwWaitTime;
while (Status.dwCurrentState == SERVICE_STOP_PENDING)
{
qDebug() << "Waiting for PostgreSQL service to stop...\n";
dwWaitTime = Status.dwWaitHint / 10;
if (dwWaitTime < 1000)
dwWaitTime = 1000;
else if (dwWaitTime > 10000)
dwWaitTime = 10000;
Sleep(dwWaitTime);
if (!QueryServiceStatus(SHandle, &Status))
{
showError();
CloseServiceHandle(SHandle);
CloseServiceHandle(SCManager);
return;
}
if (Status.dwCurrentState != SERVICE_STOP_PENDING)
break;
if (GetTickCount() - dwStartTime > dwTimeout)
{
qDebug() << "Stop of PostgreSQL service timed out.\n";
CloseServiceHandle(SHandle);
CloseServiceHandle(SCManager);
return;
}
}
if (Status.dwCurrentState != SERVICE_STOPPED)
{
qDebug() << "Restart PostgreSQL service failed. Service did not stop.\n";
CloseServiceHandle(SHandle);
CloseServiceHandle(SCManager);
return;
}
qDebug() << "PostgreSQL service stopped successfully.\n";
}
if (!StartService(SHandle, 0, NULL))
showError();
CloseServiceHandle(schService);
CloseServiceHandle(schSCManager);