backend launchers void * arguments for binary data

Change backend launcher functions to take void * for binary data
instead of char *.  This removes the need for numerous casts.

Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org

src/backend/postmaster/autovacuum.c

@@ -364,7 +364,7 @@ static void check_av_worker_gucs(void);
  * Main entry point for the autovacuum launcher process.
  */
 void
-AutoVacLauncherMain(char *startup_data, size_t startup_data_len)
+AutoVacLauncherMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 
@@ -1371,7 +1371,7 @@ avl_sigusr2_handler(SIGNAL_ARGS)
  * Main entry point for autovacuum worker processes.
  */
 void
-AutoVacWorkerMain(char *startup_data, size_t startup_data_len)
+AutoVacWorkerMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 	Oid			dbid;

src/backend/postmaster/bgworker.c

@@ -714,7 +714,7 @@ bgworker_die(SIGNAL_ARGS)
  * Main entry point for background worker processes.
  */
 void
-BackgroundWorkerMain(char *startup_data, size_t startup_data_len)
+BackgroundWorkerMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 	BackgroundWorker *worker;

src/backend/postmaster/bgwriter.c

@@ -84,7 +84,7 @@ static XLogRecPtr last_snapshot_lsn = InvalidXLogRecPtr;
  * basic execution environment, but not enabled signals yet.
  */
 void
-BackgroundWriterMain(char *startup_data, size_t startup_data_len)
+BackgroundWriterMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 	MemoryContext bgwriter_context;

src/backend/postmaster/checkpointer.c

@@ -175,7 +175,7 @@ static void ReqShutdownXLOG(SIGNAL_ARGS);
  * basic execution environment, but not enabled signals yet.
  */
 void
-CheckpointerMain(char *startup_data, size_t startup_data_len)
+CheckpointerMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 	MemoryContext checkpointer_context;

src/backend/postmaster/launch_backend.c

@@ -149,7 +149,7 @@ typedef struct
 
 #define SizeOfBackendParameters(startup_data_len) (offsetof(BackendParameters, startup_data) + startup_data_len)
 
-static void read_backend_variables(char *id, char **startup_data, size_t *startup_data_len);
+static void read_backend_variables(char *id, void **startup_data, size_t *startup_data_len);
 static void restore_backend_variables(BackendParameters *param);
 
 static bool save_backend_variables(BackendParameters *param, int child_slot,
@@ -157,10 +157,10 @@ static bool save_backend_variables(BackendParameters *param, int child_slot,
 #ifdef WIN32
 								   HANDLE childProcess, pid_t childPid,
 #endif
-								   char *startup_data, size_t startup_data_len);
+								   const void *startup_data, size_t startup_data_len);
 
 static pid_t internal_forkexec(const char *child_kind, int child_slot,
-							   char *startup_data, size_t startup_data_len,
+							   const void *startup_data, size_t startup_data_len,
 							   ClientSocket *client_sock);
 
 #endif							/* EXEC_BACKEND */
@@ -171,7 +171,7 @@ static pid_t internal_forkexec(const char *child_kind, int child_slot,
 typedef struct
 {
 	const char *name;
-	void		(*main_fn) (char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+	void		(*main_fn) (const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 	bool		shmem_attach;
 } child_process_kind;
 
@@ -225,7 +225,7 @@ PostmasterChildName(BackendType child_type)
  */
 pid_t
 postmaster_child_launch(BackendType child_type, int child_slot,
-						char *startup_data, size_t startup_data_len,
+						const void *startup_data, size_t startup_data_len,
 						ClientSocket *client_sock)
 {
 	pid_t		pid;
@@ -289,7 +289,7 @@ postmaster_child_launch(BackendType child_type, int child_slot,
  */
 static pid_t
 internal_forkexec(const char *child_kind, int child_slot,
-				  char *startup_data, size_t startup_data_len, ClientSocket *client_sock)
+				  const void *startup_data, size_t startup_data_len, ClientSocket *client_sock)
 {
 	static unsigned long tmpBackendFileNum = 0;
 	pid_t		pid;
@@ -399,7 +399,7 @@ internal_forkexec(const char *child_kind, int child_slot,
  */
 static pid_t
 internal_forkexec(const char *child_kind, int child_slot,
-				  char *startup_data, size_t startup_data_len, ClientSocket *client_sock)
+				  const void *startup_data, size_t startup_data_len, ClientSocket *client_sock)
 {
 	int			retry_count = 0;
 	STARTUPINFO si;
@@ -581,7 +581,7 @@ retry:
 void
 SubPostmasterMain(int argc, char *argv[])
 {
-	char	   *startup_data;
+	void	   *startup_data;
 	size_t		startup_data_len;
 	char	   *child_kind;
 	BackendType child_type;
@@ -699,7 +699,7 @@ save_backend_variables(BackendParameters *param,
 #ifdef WIN32
 					   HANDLE childProcess, pid_t childPid,
 #endif
-					   char *startup_data, size_t startup_data_len)
+					   const void *startup_data, size_t startup_data_len)
 {
 	if (client_sock)
 		memcpy(&param->client_sock, client_sock, sizeof(ClientSocket));
@@ -867,7 +867,7 @@ read_inheritable_socket(SOCKET *dest, InheritableSocket *src)
 #endif
 
 static void
-read_backend_variables(char *id, char **startup_data, size_t *startup_data_len)
+read_backend_variables(char *id, void **startup_data, size_t *startup_data_len)
 {
 	BackendParameters param;
 

src/backend/postmaster/pgarch.c

@@ -214,7 +214,7 @@ PgArchCanRestart(void)
 
 /* Main entry point for archiver process */
 void
-PgArchiverMain(char *startup_data, size_t startup_data_len)
+PgArchiverMain(const void *startup_data, size_t startup_data_len)
 {
 	Assert(startup_data_len == 0);
 

src/backend/postmaster/postmaster.c

@@ -3517,7 +3517,7 @@ BackendStartup(ClientSocket *client_sock)
 	bn->bgworker_notify = false;
 
 	pid = postmaster_child_launch(bn->bkend_type, bn->child_slot,
-								  (char *) &startup_data, sizeof(startup_data),
+								  &startup_data, sizeof(startup_data),
 								  client_sock);
 	if (pid < 0)
 	{
@@ -4080,7 +4080,7 @@ StartBackgroundWorker(RegisteredBgWorker *rw)
 							 rw->rw_worker.bgw_name)));
 
 	worker_pid = postmaster_child_launch(B_BG_WORKER, bn->child_slot,
-										 (char *) &rw->rw_worker, sizeof(BackgroundWorker), NULL);
+										 &rw->rw_worker, sizeof(BackgroundWorker), NULL);
 	if (worker_pid == -1)
 	{
 		/* in postmaster, fork failed ... */

src/backend/postmaster/startup.c

@@ -213,7 +213,7 @@ StartupProcExit(int code, Datum arg)
  * ----------------------------------
  */
 void
-StartupProcessMain(char *startup_data, size_t startup_data_len)
+StartupProcessMain(const void *startup_data, size_t startup_data_len)
 {
 	Assert(startup_data_len == 0);
 

src/backend/postmaster/syslogger.c

@@ -162,7 +162,7 @@ typedef struct
  * argc/argv parameters are valid only in EXEC_BACKEND case.
  */
 void
-SysLoggerMain(char *startup_data, size_t startup_data_len)
+SysLoggerMain(const void *startup_data, size_t startup_data_len)
 {
 #ifndef WIN32
 	char		logbuffer[READ_BUF_SIZE];
@@ -183,7 +183,7 @@ SysLoggerMain(char *startup_data, size_t startup_data_len)
 	 */
 #ifdef EXEC_BACKEND
 	{
-		SysloggerStartupData *slsdata = (SysloggerStartupData *) startup_data;
+		const SysloggerStartupData *slsdata = startup_data;
 
 		Assert(startup_data_len == sizeof(*slsdata));
 		syslogFile = syslogger_fdopen(slsdata->syslogFile);
@@ -699,7 +699,7 @@ SysLogger_Start(int child_slot)
 	startup_data.csvlogFile = syslogger_fdget(csvlogFile);
 	startup_data.jsonlogFile = syslogger_fdget(jsonlogFile);
 	sysloggerPid = postmaster_child_launch(B_LOGGER, child_slot,
-										   (char *) &startup_data, sizeof(startup_data), NULL);
+										   &startup_data, sizeof(startup_data), NULL);
 #else
 	sysloggerPid = postmaster_child_launch(B_LOGGER, child_slot,
 										   NULL, 0, NULL);

src/backend/postmaster/walsummarizer.c

@@ -208,7 +208,7 @@ WalSummarizerShmemInit(void)
  * Entry point for walsummarizer process.
  */
 void
-WalSummarizerMain(char *startup_data, size_t startup_data_len)
+WalSummarizerMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 	MemoryContext context;

src/backend/postmaster/walwriter.c

@@ -84,7 +84,7 @@ int			WalWriterFlushAfter = DEFAULT_WAL_WRITER_FLUSH_AFTER;
  * basic execution environment, but not enabled signals yet.
  */
 void
-WalWriterMain(char *startup_data, size_t startup_data_len)
+WalWriterMain(const void *startup_data, size_t startup_data_len)
 {
 	sigjmp_buf	local_sigjmp_buf;
 	MemoryContext walwriter_context;

src/backend/replication/logical/slotsync.c

@@ -1326,7 +1326,7 @@ reset_syncing_flag()
  * information periodically in order to create and sync the slots.
  */
 void
-ReplSlotSyncWorkerMain(char *startup_data, size_t startup_data_len)
+ReplSlotSyncWorkerMain(const void *startup_data, size_t startup_data_len)
 {
 	WalReceiverConn *wrconn = NULL;
 	char	   *dbname;

src/backend/replication/walreceiver.c

@@ -180,7 +180,7 @@ ProcessWalRcvInterrupts(void)
 
 /* Main entry point for walreceiver process */
 void
-WalReceiverMain(char *startup_data, size_t startup_data_len)
+WalReceiverMain(const void *startup_data, size_t startup_data_len)
 {
 	char		conninfo[MAXCONNINFO];
 	char	   *tmp_conninfo;

src/backend/tcop/backend_startup.c

@@ -56,9 +56,9 @@ static void StartupPacketTimeoutHandler(void);
  * client, and start the main processing loop.
  */
 void
-BackendMain(char *startup_data, size_t startup_data_len)
+BackendMain(const void *startup_data, size_t startup_data_len)
 {
-	BackendStartupData *bsdata = (BackendStartupData *) startup_data;
+	const BackendStartupData *bsdata = startup_data;
 
 	Assert(startup_data_len == sizeof(BackendStartupData));
 	Assert(MyClientSocket != NULL);

src/include/postmaster/autovacuum.h

@@ -58,8 +58,8 @@ extern void autovac_init(void);
 /* called from postmaster when a worker could not be forked */
 extern void AutoVacWorkerFailed(void);
 
-extern void AutoVacLauncherMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
-extern void AutoVacWorkerMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void AutoVacLauncherMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void AutoVacWorkerMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 extern bool AutoVacuumRequestWork(AutoVacuumWorkItemType type,
 								  Oid relationId, BlockNumber blkno);

src/include/postmaster/bgworker_internals.h

@@ -52,6 +52,6 @@ extern void ForgetUnstartedBackgroundWorkers(void);
 extern void ResetBackgroundWorkerCrashTimes(void);
 
 /* Entry point for background worker processes */
-extern void BackgroundWorkerMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void BackgroundWorkerMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 #endif							/* BGWORKER_INTERNALS_H */

src/include/postmaster/bgwriter.h

@@ -27,8 +27,8 @@ extern PGDLLIMPORT int CheckPointTimeout;
 extern PGDLLIMPORT int CheckPointWarning;
 extern PGDLLIMPORT double CheckPointCompletionTarget;
 
-extern void BackgroundWriterMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
-extern void CheckpointerMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void BackgroundWriterMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void CheckpointerMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 extern void RequestCheckpoint(int flags);
 extern void CheckpointWriteDelay(int flags, double progress);

src/include/postmaster/pgarch.h

@@ -29,7 +29,7 @@
 extern Size PgArchShmemSize(void);
 extern void PgArchShmemInit(void);
 extern bool PgArchCanRestart(void);
-extern void PgArchiverMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void PgArchiverMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 extern void PgArchWakeup(void);
 extern void PgArchForceDirScan(void);
 

src/include/postmaster/postmaster.h

@@ -109,7 +109,7 @@ extern PGDLLIMPORT struct ClientSocket *MyClientSocket;
 /* prototypes for functions in launch_backend.c */
 extern pid_t postmaster_child_launch(BackendType child_type,
 									 int child_slot,
-									 char *startup_data,
+									 const void *startup_data,
 									 size_t startup_data_len,
 									 struct ClientSocket *client_sock);
 const char *PostmasterChildName(BackendType child_type);

src/include/postmaster/startup.h

@@ -26,7 +26,7 @@
 extern PGDLLIMPORT int log_startup_progress_interval;
 
 extern void HandleStartupProcInterrupts(void);
-extern void StartupProcessMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void StartupProcessMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 extern void PreRestoreCommand(void);
 extern void PostRestoreCommand(void);
 extern bool IsPromoteSignaled(void);

src/include/postmaster/syslogger.h

@@ -90,7 +90,7 @@ extern int	SysLogger_Start(int child_slot);
 
 extern void write_syslogger_file(const char *buffer, int count, int destination);
 
-extern void SysLoggerMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void SysLoggerMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 extern bool CheckLogrotateSignal(void);
 extern void RemoveLogrotateSignalFiles(void);

src/include/postmaster/walsummarizer.h

@@ -21,7 +21,7 @@ extern PGDLLIMPORT int wal_summary_keep_time;
 
 extern Size WalSummarizerShmemSize(void);
 extern void WalSummarizerShmemInit(void);
-extern void WalSummarizerMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void WalSummarizerMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 extern void GetWalSummarizerState(TimeLineID *summarized_tli,
 								  XLogRecPtr *summarized_lsn,

src/include/postmaster/walwriter.h

@@ -18,6 +18,6 @@
 extern PGDLLIMPORT int WalWriterDelay;
 extern PGDLLIMPORT int WalWriterFlushAfter;
 
-extern void WalWriterMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void WalWriterMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 #endif							/* _WALWRITER_H */

src/include/replication/slotsync.h

@@ -26,7 +26,7 @@ extern PGDLLIMPORT char *PrimarySlotName;
 extern char *CheckAndGetDbnameFromConninfo(void);
 extern bool ValidateSlotSyncParams(int elevel);
 
-extern void ReplSlotSyncWorkerMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void ReplSlotSyncWorkerMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 extern void ShutDownSlotSync(void);
 extern bool SlotSyncWorkerCanRestart(void);

src/include/replication/walreceiver.h

@@ -486,7 +486,7 @@ walrcv_clear_result(WalRcvExecResult *walres)
 }
 
 /* prototypes for functions in walreceiver.c */
-extern void WalReceiverMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void WalReceiverMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 extern void ProcessWalRcvInterrupts(void);
 extern void WalRcvForceReply(void);
 

src/include/tcop/backend_startup.h

@@ -39,6 +39,6 @@ typedef struct BackendStartupData
 	CAC_state	canAcceptConnections;
 } BackendStartupData;
 
-extern void BackendMain(char *startup_data, size_t startup_data_len) pg_attribute_noreturn();
+extern void BackendMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn();
 
 #endif							/* BACKEND_STARTUP_H */