Add daemon support for linux like operating systems

src/main.cpp

@@ -811,6 +811,9 @@ int main(int argc, char *argv[])
 			_("Set password"))));
 	allowed_options.insert(std::make_pair("go", ValueSpec(VALUETYPE_FLAG,
 			_("Disable main menu"))));
+#else
+	allowed_options.insert(std::make_pair("daemon", ValueSpec(VALUETYPE_FLAG,
+			_("Daemonize minetestserver"))));
 #endif
 
 	Settings cmd_args;
@@ -918,6 +921,12 @@ int main(int argc, char *argv[])
 			<<", "<<minetest_build_info
 			<<std::endl;
 
+#ifdef SERVER
+	if (cmd_args.exists("daemon")) {
+		porting::daemonize();
+	}
+#endif
+
 	/*
 		Basic initialization
 	*/
@@ -1920,6 +1929,14 @@ int main(int argc, char *argv[])
 
 	debugstreams_deinit();
 
+
+#ifdef SERVER
+	if (cmd_args.exists("daemon"))
+	{
+		porting::cleanup_pid();
+	}
+#endif
+
 	return retval;
 }
 

src/porting.cpp

@@ -33,8 +33,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	#include <sys/sysctl.h>
 #elif defined(_WIN32)
 	#include <algorithm>
+#elif defined(__LINUX)
+	#include <sys/types.h>
 #endif
 #if !defined(_WIN32)
+	#include <sys/stat.h>
 	#include <unistd.h>
 	#include <sys/utsname.h>
 #endif
@@ -137,7 +140,8 @@ void signal_handler_init(void)
 /*
 	Multithreading support
 */
-int getNumberOfProcessors() {
+int getNumberOfProcessors()
+{
 #if defined(_SC_NPROCESSORS_ONLN)
 
 	return sysconf(_SC_NPROCESSORS_ONLN);
@@ -170,7 +174,8 @@ int getNumberOfProcessors() {
 }
 
 
-bool threadBindToProcessor(threadid_t tid, int pnumber) {
+bool threadBindToProcessor(threadid_t tid, int pnumber)
+{
 #if defined(_WIN32)
 
 	HANDLE hThread = OpenThread(THREAD_ALL_ACCESS, 0, tid);
@@ -224,7 +229,8 @@ bool threadBindToProcessor(threadid_t tid, int pnumber) {
 }
 
 
-bool threadSetPriority(threadid_t tid, int prio) {
+bool threadSetPriority(threadid_t tid, int prio)
+{
 #if defined(_WIN32)
 
 	HANDLE hThread = OpenThread(THREAD_ALL_ACCESS, 0, tid);
@@ -533,17 +539,20 @@ void initializePaths()
 
 static irr::IrrlichtDevice* device;
 
-void initIrrlicht(irr::IrrlichtDevice * _device) {
+void initIrrlicht(irr::IrrlichtDevice * _device)
+{
 	device = _device;
 }
 
 #ifndef SERVER
-v2u32 getWindowSize() {
+v2u32 getWindowSize()
+{
 	return device->getVideoDriver()->getScreenSize();
 }
 
 
-float getDisplayDensity() {
+float getDisplayDensity()
+{
 	float gui_scaling = g_settings->getFloat("gui_scaling");
 	// using Y here feels like a bug, this needs to be discussed later!
 	if (getWindowSize().Y <= 800) {
@@ -556,7 +565,8 @@ float getDisplayDensity() {
 	return (4.0/3.0) * gui_scaling;
 }
 
-v2u32 getDisplaySize() {
+v2u32 getDisplaySize()
+{
 	IrrlichtDevice *nulldevice = createDevice(video::EDT_NULL);
 
 	core::dimension2d<u32> deskres = nulldevice->getVideoModeList()->getDesktopResolution();
@@ -566,5 +576,93 @@ v2u32 getDisplaySize() {
 }
 #endif
 
+#ifdef SERVER
+#ifdef _WIN32
+void daemonize()
+{
+	errorstream << "daemonize not implemented on windows" << std::endl;
+}
+#else // assume posix like os
+
+static std::string get_pidfile_path()
+{
+	// make it static to make sure it won't change after first call to this fct
+	static std::string path_pidfile = "";
+	static bool initialized = false;
+
+	if (initialized)
+	{
+		return path_pidfile;
+	}
+
+	g_settings->getNoEx("pidfile", path_pidfile);
+
+	if (path_pidfile == "") {
+#ifdef RUN_IN_PLACE
+		path_pidfile = "pidfile.pid";
+#else
+		path_pidfile = "/var/run/minetest.pid";
+#endif
+	}
+	initialized = true;
+	return path_pidfile;
+}
+
+
+void daemonize()
+{
+	std::string path_pidfile = get_pidfile_path();
+
+	FILE* pidfile = fopen(path_pidfile.c_str(),"r");
+
+	if (pidfile) {
+		int pid = 0;
+		if (fscanf(pidfile, "%i", &pid) == 1) {
+			if (kill(pid, 0) == 0) {
+				errorstream <<
+						"Minetestserver is already running with pid: "
+						<< pid << std::endl;
+				exit(-1);
+			}
+		} else {
+			errorstream << "Pidfile \"" << path_pidfile << "\" "
+					"already exists but content is invalid" << std::endl <<
+					"Delete it manually if you're sure minetest isn't running!"
+					<< std::endl;
+			exit(-1);
+		}
+		fclose(pidfile);
+		pidfile = 0;
+	}
+
+	pid_t pid = fork();
+
+	if (pid > 0) {
+		pidfile = fopen(path_pidfile.c_str(),"w+");
+		if (pidfile) {
+			fprintf(pidfile,"%i",pid);
+			fclose(pidfile);
+		} else {
+			errorstream << "Failed to create pidfile: \"" << path_pidfile
+					<< "\""<< std::endl;
+		}
+		exit (0);
+	} else if (pid == 0) {
+		fclose(stdout);
+		fclose(stderr);
+		return;
+	}
+
+	errorstream << "Failed to daemonize minetest, exiting" << std::endl;
+	exit(-1);
+}
+
+void cleanup_pid()
+{
+	unlink(get_pidfile_path().c_str());
+}
+#endif
+#endif
+
 } //namespace porting
 

src/porting.h

@@ -336,6 +336,11 @@ v2u32 getDisplaySize();
 v2u32 getWindowSize();
 #endif
 
+#ifdef SERVER
+void daemonize();
+void cleanup_pid();
+#endif
+
 } // namespace porting
 
 #endif // PORTING_HEADER