Unify calling conventions for postgres/postmaster sub-main functions

There was a wild mix of calling conventions: Some were declared to
return void and didn't return, some returned an int exit code, some
claimed to return an exit code, which the callers checked, but
actually never returned, and so on.

Now all of these functions are declared to return void and decorated
with attribute noreturn and don't return.  That's easiest, and most
code already worked that way.

src/backend/main/main.c

@@ -173,7 +173,7 @@ main(int argc, char *argv[])
 
 #ifdef EXEC_BACKEND
 	if (argc > 1 && strncmp(argv[1], "--fork", 6) == 0)
-		exit(SubPostmasterMain(argc, argv));
+		SubPostmasterMain(argc, argv); /* does not return */
 #endif
 
 #ifdef WIN32
@@ -189,14 +189,13 @@ main(int argc, char *argv[])
 
 	if (argc > 1 && strcmp(argv[1], "--boot") == 0)
 		AuxiliaryProcessMain(argc, argv);		/* does not return */
-
-	if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
-		exit(GucInfoMain());
-
-	if (argc > 1 && strcmp(argv[1], "--single") == 0)
-		exit(PostgresMain(argc, argv, get_current_username(progname)));
-
-	exit(PostmasterMain(argc, argv));
+	else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
+		GucInfoMain();			/* does not return */
+	else if (argc > 1 && strcmp(argv[1], "--single") == 0)
+		PostgresMain(argc, argv, get_current_username(progname)); /* does not return */
+	else
+		PostmasterMain(argc, argv); /* does not return */
+	abort();						/* should not get here */
 }
 
 

src/backend/postmaster/autovacuum.c

@@ -269,8 +269,8 @@ int			AutovacuumLauncherPid = 0;
 static pid_t avlauncher_forkexec(void);
 static pid_t avworker_forkexec(void);
 #endif
-NON_EXEC_STATIC void AutoVacWorkerMain(int argc, char *argv[]);
-NON_EXEC_STATIC void AutoVacLauncherMain(int argc, char *argv[]);
+NON_EXEC_STATIC void AutoVacWorkerMain(int argc, char *argv[]) __attribute__((noreturn));
+NON_EXEC_STATIC void AutoVacLauncherMain(int argc, char *argv[]) __attribute__((noreturn));
 
 static Oid	do_start_worker(void);
 static void launcher_determine_sleep(bool canlaunch, bool recursing,

src/backend/postmaster/pgarch.c

@@ -101,7 +101,7 @@ static Latch mainloop_latch;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]);
+NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) __attribute__((noreturn));
 static void pgarch_exit(SIGNAL_ARGS);
 static void ArchSigHupHandler(SIGNAL_ARGS);
 static void ArchSigTermHandler(SIGNAL_ARGS);

src/backend/postmaster/pgstat.c

@@ -243,7 +243,7 @@ static instr_time total_func_time;
 static pid_t pgstat_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]);
+NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]) __attribute__((noreturn));
 static void pgstat_exit(SIGNAL_ARGS);
 static void pgstat_beshutdown_hook(int code, Datum arg);
 static void pgstat_sighup_handler(SIGNAL_ARGS);

src/backend/postmaster/postmaster.c

@@ -343,8 +343,8 @@ static void LogChildExit(int lev, const char *procname,
 			 int pid, int exitstatus);
 static void PostmasterStateMachine(void);
 static void BackendInitialize(Port *port);
-static int	BackendRun(Port *port);
-static void ExitPostmaster(int status);
+static void BackendRun(Port *port) __attribute__((noreturn));
+static void ExitPostmaster(int status) __attribute__((noreturn));
 static int	ServerLoop(void);
 static int	BackendStartup(Port *port);
 static int	ProcessStartupPacket(Port *port, bool SSLdone);
@@ -491,7 +491,7 @@ HANDLE		PostmasterHandle;
 /*
  * Postmaster main entry point
  */
-int
+void
 PostmasterMain(int argc, char *argv[])
 {
 	int			opt;
@@ -1125,7 +1125,7 @@ PostmasterMain(int argc, char *argv[])
 	 */
 	ExitPostmaster(status != STATUS_OK);
 
-	return 0;					/* not reached */
+	abort();					/* not reached */
 }
 
 
@@ -3295,7 +3295,7 @@ BackendStartup(Port *port)
 		BackendInitialize(port);
 
 		/* And run the backend */
-		proc_exit(BackendRun(port));
+		BackendRun(port);
 	}
 #endif   /* EXEC_BACKEND */
 
@@ -3539,7 +3539,7 @@ BackendInitialize(Port *port)
  *		Shouldn't return at all.
  *		If PostgresMain() fails, return status.
  */
-static int
+static void
 BackendRun(Port *port)
 {
 	char	  **av;
@@ -3610,7 +3610,7 @@ BackendRun(Port *port)
 	 */
 	MemoryContextSwitchTo(TopMemoryContext);
 
-	return (PostgresMain(ac, av, port->user_name));
+	PostgresMain(ac, av, port->user_name);
 }
 
 
@@ -3960,7 +3960,7 @@ internal_forkexec(int argc, char *argv[], Port *port)
  * have been inherited by fork() on Unix.  Remaining arguments go to the
  * subprocess FooMain() routine.
  */
-int
+void
 SubPostmasterMain(int argc, char *argv[])
 {
 	Port		port;
@@ -4111,7 +4111,7 @@ SubPostmasterMain(int argc, char *argv[])
 		CreateSharedMemoryAndSemaphores(false, 0);
 
 		/* And run the backend */
-		proc_exit(BackendRun(&port));
+		BackendRun(&port);		/* does not return */
 	}
 	if (strcmp(argv[1], "--forkboot") == 0)
 	{
@@ -4127,8 +4127,7 @@ SubPostmasterMain(int argc, char *argv[])
 		/* Attach process to shared data structures */
 		CreateSharedMemoryAndSemaphores(false, 0);
 
-		AuxiliaryProcessMain(argc - 2, argv + 2);
-		proc_exit(0);
+		AuxiliaryProcessMain(argc - 2, argv + 2); /* does not return */
 	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
@@ -4144,8 +4143,7 @@ SubPostmasterMain(int argc, char *argv[])
 		/* Attach process to shared data structures */
 		CreateSharedMemoryAndSemaphores(false, 0);
 
-		AutoVacLauncherMain(argc - 2, argv + 2);
-		proc_exit(0);
+		AutoVacLauncherMain(argc - 2, argv + 2); /* does not return */
 	}
 	if (strcmp(argv[1], "--forkavworker") == 0)
 	{
@@ -4161,8 +4159,7 @@ SubPostmasterMain(int argc, char *argv[])
 		/* Attach process to shared data structures */
 		CreateSharedMemoryAndSemaphores(false, 0);
 
-		AutoVacWorkerMain(argc - 2, argv + 2);
-		proc_exit(0);
+		AutoVacWorkerMain(argc - 2, argv + 2); /* does not return */
 	}
 	if (strcmp(argv[1], "--forkarch") == 0)
 	{
@@ -4171,8 +4168,7 @@ SubPostmasterMain(int argc, char *argv[])
 
 		/* Do not want to attach to shared memory */
 
-		PgArchiverMain(argc, argv);
-		proc_exit(0);
+		PgArchiverMain(argc, argv); /* does not return */
 	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
@@ -4181,8 +4177,7 @@ SubPostmasterMain(int argc, char *argv[])
 
 		/* Do not want to attach to shared memory */
 
-		PgstatCollectorMain(argc, argv);
-		proc_exit(0);
+		PgstatCollectorMain(argc, argv); /* does not return */
 	}
 	if (strcmp(argv[1], "--forklog") == 0)
 	{
@@ -4191,11 +4186,10 @@ SubPostmasterMain(int argc, char *argv[])
 
 		/* Do not want to attach to shared memory */
 
-		SysLoggerMain(argc, argv);
-		proc_exit(0);
+		SysLoggerMain(argc, argv); /* does not return */
 	}
 
-	return 1;					/* shouldn't get here */
+	abort();					/* shouldn't get here */
 }
 #endif   /* EXEC_BACKEND */
 

src/backend/postmaster/syslogger.c

@@ -139,6 +139,7 @@ static volatile sig_atomic_t rotation_requested = false;
 static pid_t syslogger_forkexec(void);
 static void syslogger_parseArgs(int argc, char *argv[]);
 #endif
+NON_EXEC_STATIC void SysLoggerMain(int argc, char *argv[]) __attribute__((noreturn));
 static void process_pipe_input(char *logbuffer, int *bytes_in_logbuffer);
 static void flush_pipe_input(char *logbuffer, int *bytes_in_logbuffer);
 static void open_csvlogfile(void);

src/backend/replication/walsender.c

@@ -120,7 +120,7 @@ static void WalSndLastCycleHandler(SIGNAL_ARGS);
 
 /* Prototypes for private functions */
 static bool HandleReplicationCommand(const char *cmd_string);
-static int	WalSndLoop(void);
+static void WalSndLoop(void) __attribute__((noreturn));
 static void InitWalSnd(void);
 static void WalSndHandshake(void);
 static void WalSndKill(int code, Datum arg);
@@ -135,7 +135,7 @@ static void WalSndKeepalive(char *msgbuf);
 
 
 /* Main entry point for walsender process */
-int
+void
 WalSenderMain(void)
 {
 	MemoryContext walsnd_context;
@@ -192,7 +192,7 @@ WalSenderMain(void)
 	SyncRepInitConfig();
 
 	/* Main loop of walsender */
-	return WalSndLoop();
+	WalSndLoop();
 }
 
 /*
@@ -706,7 +706,7 @@ ProcessStandbyHSFeedbackMessage(void)
 }
 
 /* Main loop of walsender process */
-static int
+static void
 WalSndLoop(void)
 {
 	char	   *output_message;
@@ -882,7 +882,7 @@ WalSndLoop(void)
 		whereToSendOutput = DestNone;
 
 	proc_exit(0);
-	return 1;					/* keep the compiler quiet */
+	abort();					/* keep the compiler quiet */
 }
 
 /* Initialize a per-walsender data structure for this walsender process */

src/backend/tcop/postgres.c

@@ -3507,7 +3507,7 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx)
  * for the session.
  * ----------------------------------------------------------------
  */
-int
+void
 PostgresMain(int argc, char *argv[], const char *username)
 {
 	const char *dbname;
@@ -3721,7 +3721,10 @@ PostgresMain(int argc, char *argv[], const char *username)
 
 	/* If this is a WAL sender process, we're done with initialization. */
 	if (am_walsender)
-		proc_exit(WalSenderMain());
+	{
+		WalSenderMain();		/* does not return */
+		abort();
+	}
 
 	/*
 	 * process any libraries that should be preloaded at backend start (this
@@ -4199,7 +4202,7 @@ PostgresMain(int argc, char *argv[], const char *username)
 	/* can't get here because the above loop never exits */
 	Assert(false);
 
-	return 1;					/* keep compiler quiet */
+	abort();					/* keep compiler quiet */
 }
 
 

src/backend/utils/misc/help_config.c

@@ -43,7 +43,7 @@ static void printMixedStruct(mixedStruct *structToPrint);
 static bool displayStruct(mixedStruct *structToDisplay);
 
 
-int
+void
 GucInfoMain(void)
 {
 	struct config_generic **guc_vars;
@@ -64,7 +64,7 @@ GucInfoMain(void)
 			printMixedStruct(var);
 	}
 
-	return 0;
+	exit(0);
 }
 
 

src/include/bootstrap/bootstrap.h

@@ -40,7 +40,7 @@ extern Form_pg_attribute attrtypes[MAXATTR];
 extern int	numattr;
 
 
-extern void AuxiliaryProcessMain(int argc, char *argv[]);
+extern void AuxiliaryProcessMain(int argc, char *argv[]) __attribute__((noreturn));
 
 extern void err_out(void);
 

src/include/pgstat.h

@@ -749,7 +749,7 @@ extern void pgstat_reset_all(void);
 extern void allow_immediate_pgstat_restart(void);
 
 #ifdef EXEC_BACKEND
-extern void PgstatCollectorMain(int argc, char *argv[]);
+extern void PgstatCollectorMain(int argc, char *argv[]) __attribute__((noreturn));
 #endif
 
 

src/include/postmaster/autovacuum.h

@@ -52,8 +52,8 @@ extern void AutoVacWorkerFailed(void);
 extern void AutoVacuumUpdateDelay(void);
 
 #ifdef EXEC_BACKEND
-extern void AutoVacLauncherMain(int argc, char *argv[]);
-extern void AutoVacWorkerMain(int argc, char *argv[]);
+extern void AutoVacLauncherMain(int argc, char *argv[]) __attribute__((noreturn));
+extern void AutoVacWorkerMain(int argc, char *argv[]) __attribute__((noreturn));
 extern void AutovacuumWorkerIAm(void);
 extern void AutovacuumLauncherIAm(void);
 #endif

src/include/postmaster/bgwriter.h

@@ -25,8 +25,8 @@ extern int	CheckPointTimeout;
 extern int	CheckPointWarning;
 extern double CheckPointCompletionTarget;
 
-extern void BackgroundWriterMain(void);
-extern void CheckpointerMain(void);
+extern void BackgroundWriterMain(void) __attribute__((noreturn));
+extern void CheckpointerMain(void) __attribute__((noreturn));
 
 extern void RequestCheckpoint(int flags);
 extern void CheckpointWriteDelay(int flags, double progress);

src/include/postmaster/pgarch.h

@@ -20,7 +20,7 @@
 extern int	pgarch_start(void);
 
 #ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]);
+extern void PgArchiverMain(int argc, char *argv[]) __attribute__((noreturn));
 #endif
 
 #endif   /* _PGARCH_H */

src/include/postmaster/postmaster.h

@@ -46,14 +46,14 @@ extern int	postmaster_alive_fds[2];
 
 extern const char *progname;
 
-extern int	PostmasterMain(int argc, char *argv[]);
+extern void PostmasterMain(int argc, char *argv[]) __attribute__((noreturn));
 extern void ClosePostmasterPorts(bool am_syslogger);
 
 extern int	MaxLivePostmasterChildren(void);
 
 #ifdef EXEC_BACKEND
 extern pid_t postmaster_forkexec(int argc, char *argv[]);
-extern int	SubPostmasterMain(int argc, char *argv[]);
+extern void	SubPostmasterMain(int argc, char *argv[]) __attribute__((noreturn));
 
 extern Size ShmemBackendArraySize(void);
 extern void ShmemBackendArrayAllocation(void);

src/include/postmaster/startup.h

@@ -13,7 +13,7 @@
 #define _STARTUP_H
 
 extern void HandleStartupProcInterrupts(void);
-extern void StartupProcessMain(void);
+extern void StartupProcessMain(void) __attribute__((noreturn));
 extern void PreRestoreCommand(void);
 extern void PostRestoreCommand(void);
 extern bool IsPromoteTriggered(void);

src/include/postmaster/syslogger.h

@@ -84,7 +84,7 @@ extern int	SysLogger_Start(void);
 extern void write_syslogger_file(const char *buffer, int count, int dest);
 
 #ifdef EXEC_BACKEND
-extern void SysLoggerMain(int argc, char *argv[]);
+extern void SysLoggerMain(int argc, char *argv[]) __attribute__((noreturn));
 #endif
 
 #endif   /* _SYSLOGGER_H */

src/include/postmaster/walwriter.h

@@ -15,6 +15,6 @@
 /* GUC options */
 extern int	WalWriterDelay;
 
-extern void WalWriterMain(void);
+extern void WalWriterMain(void) __attribute__((noreturn));
 
 #endif   /* _WALWRITER_H */

src/include/replication/walreceiver.h

@@ -109,7 +109,7 @@ typedef void (*walrcv_disconnect_type) (void);
 extern PGDLLIMPORT walrcv_disconnect_type walrcv_disconnect;
 
 /* prototypes for functions in walreceiver.c */
-extern void WalReceiverMain(void);
+extern void WalReceiverMain(void) __attribute__((noreturn));
 
 /* prototypes for functions in walreceiverfuncs.c */
 extern Size WalRcvShmemSize(void);

src/include/replication/walsender.h

@@ -26,7 +26,7 @@ extern volatile sig_atomic_t walsender_ready_to_stop;
 extern int	max_wal_senders;
 extern int	replication_timeout;
 
-extern int	WalSenderMain(void);
+extern void WalSenderMain(void) __attribute__((noreturn));
 extern void WalSndSignals(void);
 extern Size WalSndShmemSize(void);
 extern void WalSndShmemInit(void);

src/include/storage/ipc.h

@@ -64,7 +64,7 @@ typedef void (*shmem_startup_hook_type) (void);
 /* ipc.c */
 extern bool proc_exit_inprogress;
 
-extern void proc_exit(int code);
+extern void proc_exit(int code) __attribute__((noreturn));
 extern void shmem_exit(int code);
 extern void on_proc_exit(pg_on_exit_callback function, Datum arg);
 extern void on_shmem_exit(pg_on_exit_callback function, Datum arg);

src/include/tcop/tcopprot.h

@@ -61,7 +61,7 @@ extern bool check_max_stack_depth(int *newval, void **extra, GucSource source);
 extern void assign_max_stack_depth(int newval, void *extra);
 
 extern void die(SIGNAL_ARGS);
-extern void quickdie(SIGNAL_ARGS);
+extern void quickdie(SIGNAL_ARGS) __attribute__((noreturn));
 extern void StatementCancelHandler(SIGNAL_ARGS);
 extern void FloatExceptionHandler(SIGNAL_ARGS);
 extern void RecoveryConflictInterrupt(ProcSignalReason reason); /* called from SIGUSR1
@@ -70,7 +70,7 @@ extern void prepare_for_client_read(void);
 extern void client_read_ended(void);
 extern const char *process_postgres_switches(int argc, char *argv[],
 						  GucContext ctx);
-extern int	PostgresMain(int argc, char *argv[], const char *username);
+extern void PostgresMain(int argc, char *argv[], const char *username) __attribute__((noreturn));
 extern long get_stack_depth_rlimit(void);
 extern void ResetUsage(void);
 extern void ShowUsage(const char *title);

src/include/utils/help_config.h

@@ -12,6 +12,6 @@
 #ifndef HELP_CONFIG_H
 #define HELP_CONFIG_H 1
 
-extern int	GucInfoMain(void);
+extern void GucInfoMain(void) __attribute__((noreturn));
 
 #endif