#pragma once
#ifdef _WIN32
#include <csignal>
class cStartAsService
{
public:
/** Make a Windows service. */
template <auto UniversalMain>
static bool MakeIntoService()
{
SERVICE_TABLE_ENTRY ServiceTable[] =
{
{ g_ServiceName, (LPSERVICE_MAIN_FUNCTION)serviceMain<UniversalMain> },
{ nullptr, nullptr }
};
if (StartServiceCtrlDispatcher(ServiceTable) == FALSE)
{
throw std::system_error(GetLastError(), std::system_category());
}
return true;
}
private:
/** Set the internal status of the service */
static void serviceSetState(DWORD acceptedControls, DWORD newState, DWORD exitCode)
{
SERVICE_STATUS serviceStatus = {};
serviceStatus.dwCheckPoint = 0;
serviceStatus.dwControlsAccepted = acceptedControls;
serviceStatus.dwCurrentState = newState;
serviceStatus.dwServiceSpecificExitCode = 0;
serviceStatus.dwServiceType = SERVICE_WIN32;
serviceStatus.dwWaitHint = 0;
serviceStatus.dwWin32ExitCode = exitCode;
if (SetServiceStatus(g_StatusHandle, &serviceStatus) == FALSE)
{
LOGERROR("SetServiceStatus() failed\n");
}
}
/** Handle stop events from the Service Control Manager */
static void WINAPI serviceCtrlHandler(DWORD CtrlCode)
{
if (CtrlCode == SERVICE_CONTROL_STOP)
{
std::raise(SIGINT);
serviceSetState(0, SERVICE_STOP_PENDING, 0);
}
}
/* Startup logic for running as a service */
template <auto MainFunction>
static void WINAPI serviceMain(DWORD argc, TCHAR *argv[])
{
wchar_t applicationFilename[MAX_PATH];
wchar_t applicationDirectory[MAX_PATH];
// Get this binary's file path:
if (GetModuleFileName(nullptr, applicationFilename, std::size(applicationFilename)) == 0)
{
serviceSetState(0, SERVICE_STOPPED, GetLastError());
return;
}
const auto LastComponent = wcsrchr(applicationFilename, L'\\');
if (LastComponent == nullptr)
{
serviceSetState(0, SERVICE_STOPPED, E_UNEXPECTED);
return;
}
const auto LengthToLastComponent = LastComponent - applicationFilename;
// Strip off the filename, keep only the path:
wcsncpy(applicationDirectory, applicationFilename, LengthToLastComponent);
applicationDirectory[LengthToLastComponent] = L'\0'; // Make sure new path is null terminated
// Services are run by the SCM, and inherit its working directory - usually System32.
// Set the working directory to the same location as the binary.
if (SetCurrentDirectory(applicationDirectory) == FALSE)
{
serviceSetState(0, SERVICE_STOPPED, GetLastError());
return;
}
g_StatusHandle = RegisterServiceCtrlHandler(g_ServiceName, serviceCtrlHandler);
if (g_StatusHandle == nullptr)
{
OutputDebugStringA("RegisterServiceCtrlHandler() failed\n");
serviceSetState(0, SERVICE_STOPPED, GetLastError());
return;
}
serviceSetState(SERVICE_ACCEPT_STOP, SERVICE_RUNNING, 0);
char MultibyteArgV0[MAX_PATH];
char * MultibyteArgV[] = { MultibyteArgV0 };
const auto OutputSize = std::size(MultibyteArgV0);
const auto TranslateResult = wcstombs(MultibyteArgV0, argv[0], OutputSize);
if (TranslateResult == static_cast<size_t>(-1))
{
// Translation failed entirely (!):
MultibyteArgV0[0] = '\0';
}
else if (TranslateResult == OutputSize)
{
// Output too small:
MultibyteArgV0[OutputSize - 1] = '\0';
}
const auto Result = MainFunction(1, MultibyteArgV, true);
const auto Return = (Result == EXIT_SUCCESS) ? S_OK : E_FAIL;
serviceSetState(0, SERVICE_STOPPED, Return);
}
static inline SERVICE_STATUS_HANDLE g_StatusHandle = nullptr;
static inline HANDLE g_ServiceThread = INVALID_HANDLE_VALUE;
static inline wchar_t g_ServiceName[] = L"Cuberite";
};
#else
struct cStartAsService
{
/** Make a UNIX daemon. */
template <auto>
static bool MakeIntoService()
{
pid_t pid = fork();
// fork() returns a negative value on error.
if (pid < 0)
{
throw std::system_error(errno, std::system_category());
}
// Check if we are the parent or child process. Parent stops here.
if (pid > 0)
{
return true;
}
// Child process now goes quiet, running in the background.
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
return false;
}
};
#endif
