Adding upstream version 2.14.2.upstream/2.14.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 882 insertions, 0 deletions

diff --git a/lib/cli/daemoncommand.cpp b/lib/cli/daemoncommand.cpp
new file mode 100644
index 0000000..3a9ce8c
--- /dev/null
+++ b/lib/cli/daemoncommand.cpp
@@ -0,0 +1,882 @@
+/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
+
+#include "cli/daemoncommand.hpp"
+#include "cli/daemonutility.hpp"
+#include "remote/apilistener.hpp"
+#include "remote/configobjectslock.hpp"
+#include "remote/configobjectutility.hpp"
+#include "config/configcompiler.hpp"
+#include "config/configcompilercontext.hpp"
+#include "config/configitembuilder.hpp"
+#include "base/atomic.hpp"
+#include "base/defer.hpp"
+#include "base/logger.hpp"
+#include "base/application.hpp"
+#include "base/process.hpp"
+#include "base/timer.hpp"
+#include "base/utility.hpp"
+#include "base/exception.hpp"
+#include "base/convert.hpp"
+#include "base/scriptglobal.hpp"
+#include "base/context.hpp"
+#include "config.h"
+#include <cstdint>
+#include <cstring>
+#include <boost/program_options.hpp>
+#include <iostream>
+#include <fstream>
+
+#ifdef _WIN32
+#include <windows.h>
+#else /* _WIN32 */
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#endif /* _WIN32 */
+
+#ifdef HAVE_SYSTEMD
+#include <systemd/sd-daemon.h>
+#endif /* HAVE_SYSTEMD */
+
+using namespace icinga;
+namespace po = boost::program_options;
+
+static po::variables_map g_AppParams;
+
+REGISTER_CLICOMMAND("daemon", DaemonCommand);
+
+static inline
+void NotifyStatus(const char* status)
+{
+#ifdef HAVE_SYSTEMD
+	(void)sd_notifyf(0, "STATUS=%s", status);
+#endif /* HAVE_SYSTEMD */
+}
+
+/*
+ * Daemonize().  On error, this function logs by itself and exits (i.e. does not return).
+ *
+ * Implementation note: We're only supposed to call exit() in one of the forked processes.
+ * The other process calls _exit().  This prevents issues with exit handlers like atexit().
+ */
+static void Daemonize() noexcept
+{
+#ifndef _WIN32
+	try {
+		Application::UninitializeBase();
+	} catch (const std::exception& ex) {
+		Log(LogCritical, "cli")
+			<< "Failed to stop thread pool before daemonizing, unexpected error: " << DiagnosticInformation(ex);
+		exit(EXIT_FAILURE);
+	}
+
+	pid_t pid = fork();
+	if (pid == -1) {
+		Log(LogCritical, "cli")
+			<< "fork() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
+		exit(EXIT_FAILURE);
+	}
+
+	if (pid) {
+		// systemd requires that the pidfile of the daemon is written before the forking
+		// process terminates. So wait till either the forked daemon has written a pidfile or died.
+
+		int status;
+		int ret;
+		pid_t readpid;
+		do {
+			Utility::Sleep(0.1);
+
+			readpid = Application::ReadPidFile(Configuration::PidPath);
+			ret = waitpid(pid, &status, WNOHANG);
+		} while (readpid != pid && ret == 0);
+
+		if (ret == pid) {
+			Log(LogCritical, "cli", "The daemon could not be started. See log output for details.");
+			_exit(EXIT_FAILURE);
+		} else if (ret == -1) {
+			Log(LogCritical, "cli")
+				<< "waitpid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
+			_exit(EXIT_FAILURE);
+		}
+
+		_exit(EXIT_SUCCESS);
+	}
+
+	Log(LogDebug, "Daemonize()")
+		<< "Child process with PID " << Utility::GetPid() << " continues; re-initializing base.";
+
+	// Detach from controlling terminal
+	pid_t sid = setsid();
+	if (sid == -1) {
+		Log(LogCritical, "cli")
+			<< "setsid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
+		exit(EXIT_FAILURE);
+	}
+
+	try {
+		Application::InitializeBase();
+	} catch (const std::exception& ex) {
+		Log(LogCritical, "cli")
+			<< "Failed to re-initialize thread pool after daemonizing: " << DiagnosticInformation(ex);
+		exit(EXIT_FAILURE);
+	}
+#endif /* _WIN32 */
+}
+
+static void CloseStdIO(const String& stderrFile)
+{
+#ifndef _WIN32
+	int fdnull = open("/dev/null", O_RDWR);
+	if (fdnull >= 0) {
+		if (fdnull != 0)
+			dup2(fdnull, 0);
+
+		if (fdnull != 1)
+			dup2(fdnull, 1);
+
+		if (fdnull > 1)
+			close(fdnull);
+	}
+
+	const char *errPath = "/dev/null";
+
+	if (!stderrFile.IsEmpty())
+		errPath = stderrFile.CStr();
+
+	int fderr = open(errPath, O_WRONLY | O_APPEND);
+
+	if (fderr < 0 && errno == ENOENT)
+		fderr = open(errPath, O_CREAT | O_WRONLY | O_APPEND, 0600);
+
+	if (fderr >= 0) {
+		if (fderr != 2)
+			dup2(fderr, 2);
+
+		if (fderr > 2)
+			close(fderr);
+	}
+#endif
+}
+
+String DaemonCommand::GetDescription() const
+{
+	return "Starts Icinga 2.";
+}
+
+String DaemonCommand::GetShortDescription() const
+{
+	return "starts Icinga 2";
+}
+
+void DaemonCommand::InitParameters(boost::program_options::options_description& visibleDesc,
+	boost::program_options::options_description& hiddenDesc) const
+{
+	visibleDesc.add_options()
+		("config,c", po::value<std::vector<std::string> >(), "parse a configuration file")
+		("no-config,z", "start without a configuration file")
+		("validate,C", "exit after validating the configuration")
+		("dump-objects", "write icinga2.debug cache file for icinga2 object list")
+		("errorlog,e", po::value<std::string>(), "log fatal errors to the specified log file (only works in combination with --daemonize or --close-stdio)")
+#ifndef _WIN32
+		("daemonize,d", "detach from the controlling terminal")
+		("close-stdio", "do not log to stdout (or stderr) after startup")
+#endif /* _WIN32 */
+	;
+}
+
+std::vector<String> DaemonCommand::GetArgumentSuggestions(const String& argument, const String& word) const
+{
+	if (argument == "config" || argument == "errorlog")
+		return GetBashCompletionSuggestions("file", word);
+	else
+		return CLICommand::GetArgumentSuggestions(argument, word);
+}
+
+#ifndef _WIN32
+// The PID of the Icinga umbrella process
+pid_t l_UmbrellaPid = 0;
+
+// Whether the umbrella process allowed us to continue working beyond config validation
+static Atomic<bool> l_AllowedToWork (false);
+#endif /* _WIN32 */
+
+#ifdef I2_DEBUG
+/**
+ * Determine whether the developer wants to delay the worker process to attach a debugger to it.
+ *
+ * @return Internal.DebugWorkerDelay double
+ */
+static double GetDebugWorkerDelay()
+{
+	Namespace::Ptr internal = ScriptGlobal::Get("Internal", &Empty);
+
+	Value vdebug;
+	if (internal && internal->Get("DebugWorkerDelay", &vdebug))
+		return Convert::ToDouble(vdebug);
+
+	return 0.0;
+}
+#endif /* I2_DEBUG */
+
+static String l_ObjectsPath;
+
+/**
+ * Do the actual work (config loading, ...)
+ *
+ * @param configs Files to read config from
+ * @param closeConsoleLog Whether to close the console log after config loading
+ * @param stderrFile Where to log errors
+ *
+ * @return Exit code
+ */
+static inline
+int RunWorker(const std::vector<std::string>& configs, bool closeConsoleLog = false, const String& stderrFile = String())
+{
+
+#ifdef I2_DEBUG
+	double delay = GetDebugWorkerDelay();
+
+	if (delay > 0.0) {
+		Log(LogInformation, "RunWorker")
+			<< "DEBUG: Current PID: " << Utility::GetPid() << ". Sleeping for " << delay << " seconds to allow lldb/gdb -p <PID> attachment.";
+
+		Utility::Sleep(delay);
+	}
+#endif /* I2_DEBUG */
+
+	Log(LogInformation, "cli", "Loading configuration file(s).");
+	NotifyStatus("Loading configuration file(s)...");
+
+	{
+		std::vector<ConfigItem::Ptr> newItems;
+
+		if (!DaemonUtility::LoadConfigFiles(configs, newItems, l_ObjectsPath, Configuration::VarsPath)) {
+			Log(LogCritical, "cli", "Config validation failed. Re-run with 'icinga2 daemon -C' after fixing the config.");
+			NotifyStatus("Config validation failed.");
+			return EXIT_FAILURE;
+		}
+
+#ifndef _WIN32
+		Log(LogNotice, "cli")
+			<< "Notifying umbrella process (PID " << l_UmbrellaPid << ") about the config loading success";
+
+		(void)kill(l_UmbrellaPid, SIGUSR2);
+
+		Log(LogNotice, "cli")
+			<< "Waiting for the umbrella process to let us doing the actual work";
+
+		NotifyStatus("Waiting for the umbrella process to let us doing the actual work...");
+
+		if (closeConsoleLog) {
+			CloseStdIO(stderrFile);
+			Logger::DisableConsoleLog();
+		}
+
+		while (!l_AllowedToWork.load()) {
+			Utility::Sleep(0.2);
+		}
+
+		Log(LogNotice, "cli")
+			<< "The umbrella process let us continuing";
+#endif /* _WIN32 */
+
+		NotifyStatus("Restoring the previous program state...");
+
+		/* restore the previous program state */
+		try {
+			ConfigObject::RestoreObjects(Configuration::StatePath);
+		} catch (const std::exception& ex) {
+			Log(LogCritical, "cli")
+				<< "Failed to restore state file: " << DiagnosticInformation(ex);
+
+			NotifyStatus("Failed to restore state file.");
+
+			return EXIT_FAILURE;
+		}
+
+		NotifyStatus("Activating config objects...");
+
+		// activate config only after daemonization: it starts threads and that is not compatible with fork()
+		if (!ConfigItem::ActivateItems(newItems, false, true, true)) {
+			Log(LogCritical, "cli", "Error activating configuration.");
+
+			NotifyStatus("Error activating configuration.");
+
+			return EXIT_FAILURE;
+		}
+	}
+
+	/* Create the internal API object storage. Do this here too with setups without API. */
+	ConfigObjectUtility::CreateStorage();
+
+	/* Remove ignored Downtime/Comment objects. */
+	try {
+		String configDir = ConfigObjectUtility::GetConfigDir();
+		ConfigItem::RemoveIgnoredItems(configDir);
+	} catch (const std::exception& ex) {
+		Log(LogNotice, "cli")
+			<< "Cannot clean ignored downtimes/comments: " << ex.what();
+	}
+
+	ApiListener::UpdateObjectAuthority();
+
+	NotifyStatus("Startup finished.");
+
+	return Application::GetInstance()->Run();
+}
+
+#ifndef _WIN32
+// The signals to block temporarily in StartUnixWorker().
+static const sigset_t l_UnixWorkerSignals = ([]() -> sigset_t {
+	sigset_t s;
+
+	(void)sigemptyset(&s);
+	(void)sigaddset(&s, SIGUSR1);
+	(void)sigaddset(&s, SIGUSR2);
+	(void)sigaddset(&s, SIGINT);
+	(void)sigaddset(&s, SIGTERM);
+	(void)sigaddset(&s, SIGHUP);
+
+	return s;
+})();
+
+// The PID of the seamless worker currently being started by StartUnixWorker()
+static Atomic<pid_t> l_CurrentlyStartingUnixWorkerPid (-1);
+
+// The state of the seamless worker currently being started by StartUnixWorker()
+static Atomic<bool> l_CurrentlyStartingUnixWorkerReady (false);
+
+// The last temination signal we received
+static Atomic<int> l_TermSignal (-1);
+
+// Whether someone requested to re-load config (and we didn't handle that request, yet)
+static Atomic<bool> l_RequestedReload (false);
+
+// Whether someone requested to re-open logs (and we didn't handle that request, yet)
+static Atomic<bool> l_RequestedReopenLogs (false);
+
+/**
+ * Umbrella process' signal handlers
+ */
+static void UmbrellaSignalHandler(int num, siginfo_t *info, void*)
+{
+	switch (num) {
+		case SIGUSR1:
+			// Someone requested to re-open logs
+			l_RequestedReopenLogs.store(true);
+			break;
+		case SIGUSR2:
+			if (!l_CurrentlyStartingUnixWorkerReady.load()
+				&& (info->si_pid == 0 || info->si_pid == l_CurrentlyStartingUnixWorkerPid.load()) ) {
+				// The seamless worker currently being started by StartUnixWorker() successfully loaded its config
+				l_CurrentlyStartingUnixWorkerReady.store(true);
+			}
+			break;
+		case SIGINT:
+		case SIGTERM:
+			// Someone requested our termination
+
+			{
+				struct sigaction sa;
+				memset(&sa, 0, sizeof(sa));
+
+				sa.sa_handler = SIG_DFL;
+
+				(void)sigaction(num, &sa, nullptr);
+			}
+
+			l_TermSignal.store(num);
+			break;
+		case SIGHUP:
+			// Someone requested to re-load config
+			l_RequestedReload.store(true);
+			break;
+		default:
+			// Programming error (or someone has broken the userspace)
+			VERIFY(!"Caught unexpected signal");
+	}
+}
+
+/**
+ * Seamless worker's signal handlers
+ */
+static void WorkerSignalHandler(int num, siginfo_t *info, void*)
+{
+	switch (num) {
+		case SIGUSR1:
+			// Catches SIGUSR1 as long as the actual handler (logrotate)
+			// has not been installed not to let SIGUSR1 terminate the process
+			break;
+		case SIGUSR2:
+			if (info->si_pid == 0 || info->si_pid == l_UmbrellaPid) {
+				// The umbrella process allowed us to continue working beyond config validation
+				l_AllowedToWork.store(true);
+			}
+			break;
+		case SIGINT:
+		case SIGTERM:
+			if (info->si_pid == 0 || info->si_pid == l_UmbrellaPid) {
+				// The umbrella process requested our termination
+				Application::RequestShutdown();
+			}
+			break;
+		default:
+			// Programming error (or someone has broken the userspace)
+			VERIFY(!"Caught unexpected signal");
+	}
+}
+
+#ifdef HAVE_SYSTEMD
+// When we last notified the watchdog.
+static Atomic<double> l_LastNotifiedWatchdog (0);
+
+/**
+ * Notify the watchdog if not notified during the last 2.5s.
+ */
+static void NotifyWatchdog()
+{
+	double now = Utility::GetTime();
+
+	if (now - l_LastNotifiedWatchdog.load() >= 2.5) {
+		sd_notify(0, "WATCHDOG=1");
+		l_LastNotifiedWatchdog.store(now);
+	}
+}
+#endif /* HAVE_SYSTEMD */
+
+/**
+ * Starts seamless worker process doing the actual work (config loading, ...)
+ *
+ * @param configs Files to read config from
+ * @param closeConsoleLog Whether to close the console log after config loading
+ * @param stderrFile Where to log errors
+ *
+ * @return The worker's PID on success, -1 on fork(2) failure, -2 if the worker couldn't load its config
+ */
+static pid_t StartUnixWorker(const std::vector<std::string>& configs, bool closeConsoleLog = false, const String& stderrFile = String())
+{
+	Log(LogNotice, "cli")
+		<< "Spawning seamless worker process doing the actual work";
+
+	try {
+		Application::UninitializeBase();
+	} catch (const std::exception& ex) {
+		Log(LogCritical, "cli")
+			<< "Failed to stop thread pool before forking, unexpected error: " << DiagnosticInformation(ex);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Block the signal handlers we'd like to change in the child process until we changed them.
+	 * Block SIGUSR2 handler until we've set l_CurrentlyStartingUnixWorkerPid.
+	 */
+	(void)sigprocmask(SIG_BLOCK, &l_UnixWorkerSignals, nullptr);
+
+	pid_t pid = fork();
+
+	switch (pid) {
+		case -1:
+			Log(LogCritical, "cli")
+				<< "fork() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
+
+			try {
+				Application::InitializeBase();
+			} catch (const std::exception& ex) {
+				Log(LogCritical, "cli")
+					<< "Failed to re-initialize thread pool after forking (parent): " << DiagnosticInformation(ex);
+				exit(EXIT_FAILURE);
+			}
+
+			(void)sigprocmask(SIG_UNBLOCK, &l_UnixWorkerSignals, nullptr);
+			return -1;
+
+		case 0:
+			try {
+				{
+					struct sigaction sa;
+					memset(&sa, 0, sizeof(sa));
+
+					sa.sa_handler = SIG_DFL;
+
+					(void)sigaction(SIGUSR1, &sa, nullptr);
+				}
+
+				{
+					struct sigaction sa;
+					memset(&sa, 0, sizeof(sa));
+
+					sa.sa_handler = SIG_IGN;
+
+					(void)sigaction(SIGHUP, &sa, nullptr);
+				}
+
+				{
+					struct sigaction sa;
+					memset(&sa, 0, sizeof(sa));
+
+					sa.sa_sigaction = &WorkerSignalHandler;
+					sa.sa_flags = SA_RESTART | SA_SIGINFO;
+
+					(void)sigaction(SIGUSR1, &sa, nullptr);
+					(void)sigaction(SIGUSR2, &sa, nullptr);
+					(void)sigaction(SIGINT, &sa, nullptr);
+					(void)sigaction(SIGTERM, &sa, nullptr);
+				}
+
+				(void)sigprocmask(SIG_UNBLOCK, &l_UnixWorkerSignals, nullptr);
+
+				try {
+					Application::InitializeBase();
+				} catch (const std::exception& ex) {
+					Log(LogCritical, "cli")
+						<< "Failed to re-initialize thread pool after forking (child): " << DiagnosticInformation(ex);
+					_exit(EXIT_FAILURE);
+				}
+
+				try {
+					Process::InitializeSpawnHelper();
+				} catch (const std::exception& ex) {
+					Log(LogCritical, "cli")
+						<< "Failed to initialize process spawn helper after forking (child): " << DiagnosticInformation(ex);
+					_exit(EXIT_FAILURE);
+				}
+
+				_exit(RunWorker(configs, closeConsoleLog, stderrFile));
+			} catch (const std::exception& ex) {
+				Log(LogCritical, "cli") << "Exception in main process: " << DiagnosticInformation(ex);
+				_exit(EXIT_FAILURE);
+			} catch (...) {
+				_exit(EXIT_FAILURE);
+			}
+
+		default:
+			l_CurrentlyStartingUnixWorkerPid.store(pid);
+			(void)sigprocmask(SIG_UNBLOCK, &l_UnixWorkerSignals, nullptr);
+
+			Log(LogNotice, "cli")
+				<< "Spawned worker process (PID " << pid << "), waiting for it to load its config";
+
+			// Wait for the newly spawned process to either load its config or fail.
+			for (;;) {
+#ifdef HAVE_SYSTEMD
+				NotifyWatchdog();
+#endif /* HAVE_SYSTEMD */
+
+				if (waitpid(pid, nullptr, WNOHANG) > 0) {
+					Log(LogNotice, "cli")
+						<< "Worker process couldn't load its config";
+
+					pid = -2;
+					break;
+				}
+
+				if (l_CurrentlyStartingUnixWorkerReady.load()) {
+					Log(LogNotice, "cli")
+						<< "Worker process successfully loaded its config";
+					break;
+				}
+
+				Utility::Sleep(0.2);
+			}
+
+			// Reset flags for the next time
+			l_CurrentlyStartingUnixWorkerPid.store(-1);
+			l_CurrentlyStartingUnixWorkerReady.store(false);
+
+			try {
+				Application::InitializeBase();
+			} catch (const std::exception& ex) {
+				Log(LogCritical, "cli")
+					<< "Failed to re-initialize thread pool after forking (parent): " << DiagnosticInformation(ex);
+				exit(EXIT_FAILURE);
+			}
+	}
+
+	return pid;
+}
+
+/**
+ * Workaround to instantiate Application (which is abstract) in DaemonCommand#Run()
+ */
+class PidFileManagementApp : public Application
+{
+public:
+	inline int Main() override
+	{
+		return EXIT_FAILURE;
+	}
+};
+#endif /* _WIN32 */
+
+/**
+ * The entry point for the "daemon" CLI command.
+ *
+ * @returns An exit status.
+ */
+int DaemonCommand::Run(const po::variables_map& vm, const std::vector<std::string>& ap) const
+{
+#ifdef _WIN32
+	SetConsoleOutputCP(65001);
+#endif /* _WIN32 */
+
+	Logger::EnableTimestamp();
+
+	Log(LogInformation, "cli")
+		<< "Icinga application loader (version: " << Application::GetAppVersion()
+#ifdef I2_DEBUG
+		<< "; debug"
+#endif /* I2_DEBUG */
+		<< ")";
+
+	std::vector<std::string> configs;
+	if (vm.count("config") > 0)
+		configs = vm["config"].as<std::vector<std::string> >();
+	else if (!vm.count("no-config")) {
+		/* The implicit string assignment is needed for Windows builds. */
+		String configDir = Configuration::ConfigDir;
+		configs.push_back(configDir + "/icinga2.conf");
+	}
+
+	if (vm.count("dump-objects")) {
+		if (!vm.count("validate")) {
+			Log(LogCritical, "cli", "--dump-objects is not allowed without -C");
+			return EXIT_FAILURE;
+		}
+
+		l_ObjectsPath = Configuration::ObjectsPath;
+	}
+
+	if (vm.count("validate")) {
+		Log(LogInformation, "cli", "Loading configuration file(s).");
+
+		std::vector<ConfigItem::Ptr> newItems;
+
+		if (!DaemonUtility::LoadConfigFiles(configs, newItems, l_ObjectsPath, Configuration::VarsPath)) {
+			Log(LogCritical, "cli", "Config validation failed. Re-run with 'icinga2 daemon -C' after fixing the config.");
+			return EXIT_FAILURE;
+		}
+
+		Log(LogInformation, "cli", "Finished validating the configuration file(s).");
+		return EXIT_SUCCESS;
+	}
+
+	{
+		pid_t runningpid = Application::ReadPidFile(Configuration::PidPath);
+		if (runningpid > 0) {
+			Log(LogCritical, "cli")
+				<< "Another instance of Icinga already running with PID " << runningpid;
+			return EXIT_FAILURE;
+		}
+	}
+
+	if (vm.count("daemonize")) {
+		// this subroutine either succeeds, or logs an error
+		// and terminates the process (does not return).
+		Daemonize();
+	}
+
+#ifndef _WIN32
+	/* The Application manages the PID file,
+	 * but on *nix this process doesn't load any config
+	 * so there's no central Application instance.
+	 */
+	PidFileManagementApp app;
+
+	try {
+		app.UpdatePidFile(Configuration::PidPath);
+	} catch (const std::exception&) {
+		Log(LogCritical, "Application")
+			<< "Cannot update PID file '" << Configuration::PidPath << "'. Aborting.";
+		return EXIT_FAILURE;
+	}
+
+	Defer closePidFile ([&app]() {
+		app.ClosePidFile(true);
+	});
+#endif /* _WIN32 */
+
+	if (vm.count("daemonize")) {
+		// After disabling the console log, any further errors will go to the configured log only.
+		// Let's try to make this clear and say good bye.
+		Log(LogInformation, "cli", "Closing console log.");
+
+		String errorLog;
+		if (vm.count("errorlog"))
+			errorLog = vm["errorlog"].as<std::string>();
+
+		CloseStdIO(errorLog);
+		Logger::DisableConsoleLog();
+	}
+
+#ifdef _WIN32
+	try {
+		return RunWorker(configs);
+	} catch (const std::exception& ex) {
+		Log(LogCritical, "cli")	<< "Exception in main process: " << DiagnosticInformation(ex);
+		return EXIT_FAILURE;
+	} catch (...) {
+		return EXIT_FAILURE;
+	}
+#else /* _WIN32 */
+	l_UmbrellaPid = getpid();
+	Application::SetUmbrellaProcess(l_UmbrellaPid);
+
+	{
+		struct sigaction sa;
+		memset(&sa, 0, sizeof(sa));
+
+		sa.sa_sigaction = &UmbrellaSignalHandler;
+		sa.sa_flags = SA_NOCLDSTOP | SA_RESTART | SA_SIGINFO;
+
+		(void)sigaction(SIGUSR1, &sa, nullptr);
+		(void)sigaction(SIGUSR2, &sa, nullptr);
+		(void)sigaction(SIGINT, &sa, nullptr);
+		(void)sigaction(SIGTERM, &sa, nullptr);
+		(void)sigaction(SIGHUP, &sa, nullptr);
+	}
+
+	bool closeConsoleLog = !vm.count("daemonize") && vm.count("close-stdio");
+
+	String errorLog;
+	if (vm.count("errorlog"))
+		errorLog = vm["errorlog"].as<std::string>();
+
+	// The PID of the current seamless worker
+	pid_t currentWorker = StartUnixWorker(configs, closeConsoleLog, errorLog);
+
+	if (currentWorker < 0) {
+		return EXIT_FAILURE;
+	}
+
+	if (closeConsoleLog) {
+		// After disabling the console log, any further errors will go to the configured log only.
+		// Let's try to make this clear and say good bye.
+		Log(LogInformation, "cli", "Closing console log.");
+
+		CloseStdIO(errorLog);
+		Logger::DisableConsoleLog();
+	}
+
+	// Immediately allow the first (non-reload) worker to continue working beyond config validation
+	(void)kill(currentWorker, SIGUSR2);
+
+#ifdef HAVE_SYSTEMD
+	sd_notify(0, "READY=1");
+#endif /* HAVE_SYSTEMD */
+
+	// Whether we already forwarded a termination signal to the seamless worker
+	bool requestedTermination = false;
+
+	// Whether we already notified systemd about our termination
+	bool notifiedTermination = false;
+
+	for (;;) {
+#ifdef HAVE_SYSTEMD
+		NotifyWatchdog();
+#endif /* HAVE_SYSTEMD */
+
+		if (!requestedTermination) {
+			int termSig = l_TermSignal.load();
+			if (termSig != -1) {
+				Log(LogNotice, "cli")
+					<< "Got signal " << termSig << ", forwarding to seamless worker (PID " << currentWorker << ")";
+
+				(void)kill(currentWorker, termSig);
+				requestedTermination = true;
+
+#ifdef HAVE_SYSTEMD
+				if (!notifiedTermination) {
+					notifiedTermination = true;
+					sd_notify(0, "STOPPING=1");
+				}
+#endif /* HAVE_SYSTEMD */
+			}
+		}
+
+		if (l_RequestedReload.exchange(false)) {
+			Log(LogInformation, "Application")
+				<< "Got reload command: Starting new instance.";
+
+#ifdef HAVE_SYSTEMD
+			sd_notify(0, "RELOADING=1");
+#endif /* HAVE_SYSTEMD */
+
+			// The old process is still active, yet.
+			// Its config changes would not be visible to the new one after config load.
+			ConfigObjectsExclusiveLock lock;
+
+			pid_t nextWorker = StartUnixWorker(configs);
+
+			switch (nextWorker) {
+				case -1:
+					break;
+				case -2:
+					Log(LogCritical, "Application", "Found error in config: reloading aborted");
+					Application::SetLastReloadFailed(Utility::GetTime());
+					break;
+				default:
+					Log(LogInformation, "Application")
+						<< "Reload done, old process shutting down. Child process with PID '" << nextWorker << "' is taking over.";
+
+					NotifyStatus("Shutting down old instance...");
+
+					Application::SetLastReloadFailed(0);
+					(void)kill(currentWorker, SIGTERM);
+
+					{
+						double start = Utility::GetTime();
+
+						while (waitpid(currentWorker, nullptr, 0) == -1 && errno == EINTR) {
+	#ifdef HAVE_SYSTEMD
+							NotifyWatchdog();
+	#endif /* HAVE_SYSTEMD */
+						}
+
+						Log(LogNotice, "cli")
+							<< "Waited for " << Utility::FormatDuration(Utility::GetTime() - start) << " on old process to exit.";
+					}
+
+					// Old instance shut down, allow the new one to continue working beyond config validation
+					(void)kill(nextWorker, SIGUSR2);
+
+					NotifyStatus("Shut down old instance.");
+
+					currentWorker = nextWorker;
+			}
+
+#ifdef HAVE_SYSTEMD
+			sd_notify(0, "READY=1");
+#endif /* HAVE_SYSTEMD */
+
+		}
+
+		if (l_RequestedReopenLogs.exchange(false)) {
+			Log(LogNotice, "cli")
+				<< "Got signal " << SIGUSR1 << ", forwarding to seamless worker (PID " << currentWorker << ")";
+
+			(void)kill(currentWorker, SIGUSR1);
+		}
+
+		{
+			int status;
+			if (waitpid(currentWorker, &status, WNOHANG) > 0) {
+				Log(LogNotice, "cli")
+					<< "Seamless worker (PID " << currentWorker << ") stopped, stopping as well";
+
+#ifdef HAVE_SYSTEMD
+				if (!notifiedTermination) {
+					notifiedTermination = true;
+					sd_notify(0, "STOPPING=1");
+				}
+#endif /* HAVE_SYSTEMD */
+
+				// If killed by signal, forward it via the exit code (to be as seamless as possible)
+				return WIFSIGNALED(status) ? 128 + WTERMSIG(status) : WEXITSTATUS(status);
+			}
+		}
+
+		Utility::Sleep(0.2);
+	}
+#endif /* _WIN32 */
+}