Factor Supervisor initialization data to separate struct from Stem

src/supervisor/Supervisor.cc

@@ -46,8 +46,23 @@ using namespace zeek;
 std::optional<Supervisor::SupervisedNode> Supervisor::supervised_node;
 
 namespace {
+
 struct Stem {
-	Stem(Supervisor::StemState stem_state);
+	/**
+	* State used to initalialize the Stem process.
+	*/
+	struct State {
+		/**
+		* Bidirectional pipes that allow the Supervisor and Stem to talk.
+		*/
+		std::unique_ptr<zeek::detail::PipePair> pipe;
+		/**
+		* The Stem's parent process ID (i.e. PID of the Supervisor).
+		*/
+		pid_t parent_pid = 0;
+	};
+
+	Stem(State stem_state);
 
 	~Stem();
 
@@ -164,8 +179,8 @@ void zeek::detail::ParentProcessCheckTimer::Dispatch(double t, bool is_expire)
 		                                           interval));
 	}
 
-Supervisor::Supervisor(Supervisor::Config cfg, StemState ss)
-	: config(std::move(cfg)), stem_pid(ss.pid), stem_pipe(std::move(ss.pipe))
+Supervisor::Supervisor(Supervisor::Config cfg, StemHandle sh)
+	: config(std::move(cfg)), stem_pid(sh.pid), stem_pipe(std::move(sh.pipe))
 	{
 	DBG_LOG(DBG_SUPERVISOR, "forked stem process %d", stem_pid);
 	setsignal(SIGCHLD, supervisor_signal_handler);
@@ -426,7 +441,7 @@ size_t Supervisor::ProcessMessages()
 	return msgs.size();
 	}
 
-Stem::Stem(Supervisor::StemState ss)
+Stem::Stem(State ss)
 	: parent_pid(ss.parent_pid), signal_flare(new zeek::detail::Flare()), pipe(std::move(ss.pipe))
 	{
 	zeek::set_thread_name("zeek.stem");
@@ -904,7 +919,7 @@ std::optional<Supervisor::SupervisedNode> Stem::Poll()
 	return {};
 	}
 
-std::optional<Supervisor::StemState> Supervisor::CreateStem(bool supervisor_mode)
+std::optional<Supervisor::StemHandle> Supervisor::CreateStem(bool supervisor_mode)
 	{
 	// If the Stem needs to be re-created via fork()/exec(), then the necessary
 	// state information is communicated via ZEEK_STEM env. var.
@@ -928,42 +943,41 @@ std::optional<Supervisor::StemState> Supervisor::CreateStem(bool supervisor_mode
 		for ( auto i = 0; i < 4; ++i )
 			fds[i] = std::stoi(zeek_stem_nums[i + 1]);
 
-		StemState ss;
+		Stem::State ss;
 		ss.pipe = std::make_unique<zeek::detail::PipePair>(FD_CLOEXEC, O_NONBLOCK, fds);
 		ss.parent_pid = stem_ppid;
-		zeek::Supervisor::RunStem(std::move(ss));
+
+		Stem stem{std::move(ss)};
+		supervised_node = stem.Run();
 		return {};
 		}
 
 	if ( ! supervisor_mode )
 		return {};
 
-	StemState ss;
+	Stem::State ss;
 	ss.pipe = std::make_unique<zeek::detail::PipePair>(FD_CLOEXEC, O_NONBLOCK);
 	ss.parent_pid = getpid();
-	ss.pid = fork();
+	auto pid = fork();
 
-	if ( ss.pid == -1 )
+	if ( pid == -1 )
 		{
 		fprintf(stderr, "failed to fork Zeek supervisor stem process: %s\n",
 			    strerror(errno));
 		exit(1);
 		}
 
-	if ( ss.pid == 0 )
+	if ( pid == 0 )
 		{
-		zeek::Supervisor::RunStem(std::move(ss));
+		Stem stem{std::move(ss)};
+		supervised_node = stem.Run();
 		return {};
 		}
 
-	return std::optional<Supervisor::StemState>(std::move(ss));
-	}
-
-Supervisor::SupervisedNode Supervisor::RunStem(StemState stem_state)
-	{
-	Stem s(std::move(stem_state));
-	supervised_node = s.Run();
-	return *supervised_node;
+	StemHandle sh;
+	sh.pipe = std::move(ss.pipe);
+	sh.pid = pid;
+	return std::optional<Supervisor::StemHandle>(std::move(sh));
 	}
 
 static BifEnum::Supervisor::ClusterRole role_str_to_enum(std::string_view r)

src/supervisor/Supervisor.h

@@ -235,17 +235,13 @@ public:
 	};
 
 	/**
-	 * State used to initalialize the Stem process.
+	 * State used to initalialize and communicate with the Stem process.
 	 */
-	struct StemState {
+	struct StemHandle {
 		/**
 		 * Bidirectional pipes that allow the Supervisor and Stem to talk.
 		 */
 		std::unique_ptr<zeek::detail::PipePair> pipe;
-		/**
-		 * The Stem's parent process ID (i.e. PID of the Supervisor).
-		 */
-		pid_t parent_pid = 0;
 		/**
 		 * The Stem's process ID.
 		 */
@@ -261,7 +257,7 @@ public:
 	 * function but a node it spawns via fork() will return from it and
 	 * information about it is available in ThisNode().
 	 */
-	static std::optional<StemState> CreateStem(bool supervisor_mode);
+	static std::optional<StemHandle> CreateStem(bool supervisor_mode);
 
 	/**
 	 * @return  the state which describes what a supervised node should know
@@ -275,10 +271,10 @@ public:
 
 	/**
 	 * Create a new Supervisor object.
-	 * @param stem_state  information about the Stem process that was already
+	 * @param stem_handle information about the Stem process that was already
 	 * created via CreateStem()
 	 */
-	Supervisor(Config cfg, StemState stem_state);
+	Supervisor(Config cfg, StemHandle stem_handle);
 
 	/**
 	 * Destruction also cleanly shuts down the entire supervised process tree.
@@ -365,19 +361,6 @@ private:
 	const char* Tag() override
 		{ return "zeek::Supervisor"; }
 
-	/**
-	 * Run the Stem process.  The Stem process will receive instructions from
-	 * the Supervisor to manipulate the process hierarchy and it's in charge
-	 * of directly monitoring for whether any nodes die premature and need
-	 * to be revived.
-	 * @param pipe  bidirectional pipes that allow the Supervisor and Stem
-	 * process to communicate.
-	 * @param pid  the Stem's parent process ID (i.e. the PID of the Supervisor)
-	 * @return  state which describes what a supervised node should know about
-	 * itself.  I.e. this function only returns from a fork()'d child process.
-	 */
-	static SupervisedNode RunStem(StemState stem_state);
-
 	static std::optional<SupervisedNode> supervised_node;
 
 	Config config;

src/zeek-setup.cc

@@ -415,7 +415,7 @@ zeek::detail::SetupResult zeek::detail::setup(int argc, char** argv,
 		exit(context.run());
 		}
 
-	auto stem_state = zeek::Supervisor::CreateStem(options.supervisor_mode);
+	auto stem = zeek::Supervisor::CreateStem(options.supervisor_mode);
 
 	if ( zeek::Supervisor::ThisNode() )
 		zeek::Supervisor::ThisNode()->Init(&options);
@@ -487,8 +487,7 @@ zeek::detail::SetupResult zeek::detail::setup(int argc, char** argv,
 		zeek::Supervisor::Config cfg = {};
 		cfg.zeek_exe_path = zeek_exe_path;
 		options.filter_supervisor_options();
-		zeek::supervisor_mgr = new zeek::Supervisor(std::move(cfg),
-		                                            std::move(*stem_state));
+		zeek::supervisor_mgr = new zeek::Supervisor(std::move(cfg), std::move(*stem));
 		}
 
 	const char* seed_load_file = zeekenv("ZEEK_SEED_FILE");