Add --reload command-line parameter.

Refs #5788

etc/init.d/icinga2.cmake

@@ -61,11 +61,13 @@ start() {
 	chown $ICINGA2_USER:$ICINGA2_COMMAND_GROUP $ICINGA2_STATE_DIR/run/icinga2/cmd
 	chmod 2755 $ICINGA2_STATE_DIR/run/icinga2/cmd
 
-        echo "Starting Icinga 2: "
-        $DAEMON -c $ICINGA2_CONFIG_FILE -d -e $ICINGA2_ERROR_LOG -u $ICINGA2_USER -g $ICINGA2_GROUP
-
-        echo "Done"
-        echo
+	echo "Starting Icinga 2: "
+	if ! $DAEMON -c $ICINGA2_CONFIG_FILE -d -e $ICINGA2_ERROR_LOG -u $ICINGA2_USER -g $ICINGA2_GROUP; then
+		echo "Error starting Icinga."
+		exit 1
+	else
+		echo "Done"
+	fi
 }
 
 # Restart Icinga 2
@@ -104,15 +106,9 @@ stop() {
 # Reload Icinga 2
 reload() {
 	printf "Reloading Icinga 2: "
-	if [ ! -e $ICINGA2_PID_FILE ]; then
-		echo "The PID file '$ICINGA2_PID_FILE' does not exist."
+	if ! $DAEMON -c $ICINGA2_CONFIG_FILE -d --reload -e $ICINGA2_ERROR_LOG -u $ICINGA2_USER -g $ICINGA2_GROUP; then
+		echo "Error reloading Icinga."
 		exit 1
-	fi
-
-	pid=`cat $ICINGA2_PID_FILE`
-
-	if ! kill -HUP $pid >/dev/null 2>&1; then
-		echo "Failed - Icinga 2 is not running."
 	else
 		echo "Done"
 	fi
@@ -162,7 +158,6 @@ case "$1" in
         start
         ;;
   reload)
-	checkconfig reload fail
 	reload
 	;;
   checkconfig)

icinga-app/icinga.cpp

@@ -187,6 +187,34 @@ static bool Daemonize(const String& stderrFile)
 	return true;
 }
 
+/**
+ * Terminate another process and wait till it has ended
+ *
+ * @params target PID of the process to end
+ */
+static void TerminateAndWaitForEnd(pid_t target)
+{
+#ifndef _WIN32
+	// allow 15 seconds timeout
+	double timeout = Utility::GetTime() + 15;
+
+	int ret = kill(target, SIGTERM);
+
+	while(Utility::GetTime() < timeout && (ret==0 || errno!=ESRCH))
+	{
+		Utility::Sleep(0.1);
+		ret = kill(target, 0);
+	}
+
+	// timeout and the process still seems to live: kill it
+	if (ret == 0 || errno != ESRCH)
+		kill(target, SIGKILL);
+
+#else
+	// TODO: implement this for Win32
+#endif /* _WIN32 */
+}
+
 int Main(void)
 {
 	int argc = Application::GetArgC();
@@ -252,6 +280,7 @@ int Main(void)
 		("validate,C", "exit after validating the configuration")
 		("debug,x", "enable debugging")
 		("errorlog,e", po::value<std::string>(), "log fatal errors to the specified log file (only works in combination with --daemonize)")
+		("reload,r", "reload a running icinga instance")
 #ifndef _WIN32
 		("daemonize,d", "detach from the controlling terminal")
 		("user,u", po::value<std::string>(), "user to run Icinga as")
@@ -405,6 +434,17 @@ int Main(void)
 		return EXIT_FAILURE;
 	}
 
+	pid_t runningpid = Application::ReadPidFile(Application::GetPidPath());
+	if (g_AppParams.count("reload")) {
+		if (runningpid < 0) {
+			Log(LogCritical, "icinga-app", "No instance of Icinga currently running: can't reload.");
+			return EXIT_FAILURE;
+		}
+	} else if (!g_AppParams.count("validate") && runningpid >= 0) {
+		Log(LogCritical, "icinga-app", "Another instance of Icinga already running at PID " + Convert::ToString(runningpid));
+		return EXIT_FAILURE;
+	}
+
 	if (!LoadConfigFiles(appType))
 		return EXIT_FAILURE;
 
@@ -413,6 +453,12 @@ int Main(void)
 		return EXIT_SUCCESS;
 	}
 
+	if (g_AppParams.count("reload")) {
+		Log(LogInformation, "icinga-app", "Terminating previous instance of icinga (PID " + Convert::ToString(runningpid) + ")");
+		TerminateAndWaitForEnd(runningpid);
+		Log(LogInformation, "icinga-app", "Previous instance has ended, taking over now.");
+	}
+
 	if (g_AppParams.count("daemonize")) {
 		String errorLog;
 

lib/base/application.cpp

@@ -638,7 +638,7 @@ void Application::UpdatePidFile(const String& filename)
 	}
 #endif /* _WIN32 */
 
-	fprintf(m_PidFile, "%d", Utility::GetPid());
+	fprintf(m_PidFile, "%d\n", Utility::GetPid());
 	fflush(m_PidFile);
 }
 
@@ -656,6 +656,60 @@ void Application::ClosePidFile(void)
 	m_PidFile = NULL;
 }
 
+/**
+ * Checks if another process currently owns the pidfile and read it
+ *
+ * @param filename The name of the PID file.
+ * @returns -1: no process owning the pidfile, pid of the process otherwise
+ */
+pid_t Application::ReadPidFile(const String& filename)
+{
+	FILE *pidfile = fopen(filename.CStr(), "r");
+
+	if (pidfile == NULL)
+		return -1;
+
+#ifndef _WIN32
+	int fd = fileno(pidfile);
+
+	struct flock lock;
+
+	lock.l_start = 0;
+	lock.l_len = 0;
+	lock.l_type = F_WRLCK;
+	lock.l_whence = SEEK_SET;
+
+	if (fcntl(fd, F_GETLK, &lock) < 0) {
+		int error = errno;
+		fclose(pidfile);
+		BOOST_THROW_EXCEPTION(posix_error()
+		    << boost::errinfo_api_function("fcntl")
+		    << boost::errinfo_errno(error));
+	}
+
+	if (lock.l_type == F_UNLCK) {
+		// nobody has locked the file: no icinga running
+		fclose(pidfile);
+		return -1;
+	}
+#endif /* _WIN32 */
+
+	pid_t runningpid;
+	int res = fscanf(pidfile, "%d", &runningpid);
+	fclose(pidfile);
+
+	// bogus result?
+	if (res != 1)
+		return -1;
+
+#ifdef _WIN32
+	// TODO: add check if the read pid is still running or not
+#endif /* _WIN32 */
+
+	return runningpid;
+}
+
+
 /**
  * Retrieves the path of the installation prefix.
  *

lib/base/application.h

@@ -69,6 +69,7 @@ public:
 
 	void UpdatePidFile(const String& filename);
 	void ClosePidFile(void);
+	static pid_t ReadPidFile(const String& filename);
 
 	static String GetExePath(const String& argv0);