Commonalize process startup code.

Move common code, that was duplicated in every postmaster child/every
standalone process, into two functions in miscinit.c.  Not only does
that already result in a fair amount of net code reduction but it also
makes it much easier to remove more duplication in the future. The
prime motivation wasn't code deduplication though, but easier addition
of new common code.

src/backend/bootstrap/bootstrap.c

@@ -14,7 +14,6 @@
  */
 #include "postgres.h"
 
-#include <time.h>
 #include <unistd.h>
 #include <signal.h>
 
@@ -191,19 +190,11 @@ AuxiliaryProcessMain(int argc, char *argv[])
 	char	   *userDoption = NULL;
 
 	/*
-	 * initialize globals
+	 * Initialize process environment (already done if under postmaster, but
+	 * not if standalone).
 	 */
-	MyProcPid = getpid();
-
-	MyStartTime = time(NULL);
-
-	/* Compute paths, if we didn't inherit them from postmaster */
-	if (my_exec_path[0] == '\0')
-	{
-		if (find_my_exec(progname, my_exec_path) < 0)
-			elog(FATAL, "%s: could not locate my own executable path",
-				 progname);
-	}
+	if (!IsUnderPostmaster)
+		InitStandaloneProcess(argv[0]);
 
 	/*
 	 * process command arguments
@@ -515,15 +506,6 @@ bootstrap_signals(void)
 {
 	if (IsUnderPostmaster)
 	{
-		/*
-		 * If possible, make this process a group leader, so that the
-		 * postmaster can signal any child processes too.
-		 */
-#ifdef HAVE_SETSID
-		if (setsid() < 0)
-			elog(FATAL, "setsid() failed: %m");
-#endif
-
 		/*
 		 * Properly accept or ignore signals the postmaster might send us
 		 */

src/backend/postmaster/autovacuum.c

@@ -64,7 +64,6 @@
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/time.h>
-#include <time.h>
 #include <unistd.h>
 
 #include "access/heapam.h"
@@ -383,12 +382,11 @@ StartAutoVacLauncher(void)
 #ifndef EXEC_BACKEND
 		case 0:
 			/* in postmaster child ... */
+			InitPostmasterChild();
+
 			/* Close the postmaster's sockets */
 			ClosePostmasterPorts(false);
 
-			/* Lose the postmaster's on-exit routines */
-			on_exit_reset();
-
 			AutoVacLauncherMain(0, NULL);
 			break;
 #endif
@@ -408,16 +406,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 {
 	sigjmp_buf	local_sigjmp_buf;
 
-	/* we are a postmaster subprocess now */
-	IsUnderPostmaster = true;
 	am_autovacuum_launcher = true;
 
-	/* reset MyProcPid */
-	MyProcPid = getpid();
-
-	/* record Start Time for logging */
-	MyStartTime = time(NULL);
-
 	/* Identify myself via ps */
 	init_ps_display("autovacuum launcher process", "", "", "");
 
@@ -429,17 +419,6 @@ AutoVacLauncherMain(int argc, char *argv[])
 
 	SetProcessingMode(InitProcessing);
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (autovacuum probably never has any
-	 * child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Set up signal handlers.  We operate on databases much like a regular
 	 * backend, so we use the same signal handling.  See equivalent code in
@@ -1455,12 +1434,11 @@ StartAutoVacWorker(void)
 #ifndef EXEC_BACKEND
 		case 0:
 			/* in postmaster child ... */
+			InitPostmasterChild();
+
 			/* Close the postmaster's sockets */
 			ClosePostmasterPorts(false);
 
-			/* Lose the postmaster's on-exit routines */
-			on_exit_reset();
-
 			AutoVacWorkerMain(0, NULL);
 			break;
 #endif
@@ -1481,32 +1459,13 @@ AutoVacWorkerMain(int argc, char *argv[])
 	sigjmp_buf	local_sigjmp_buf;
 	Oid			dbid;
 
-	/* we are a postmaster subprocess now */
-	IsUnderPostmaster = true;
 	am_autovacuum_worker = true;
 
-	/* reset MyProcPid */
-	MyProcPid = getpid();
-
-	/* record Start Time for logging */
-	MyStartTime = time(NULL);
-
 	/* Identify myself via ps */
 	init_ps_display("autovacuum worker process", "", "", "");
 
 	SetProcessingMode(InitProcessing);
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (autovacuum probably never has any
-	 * child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Set up signal handlers.  We operate on databases much like a regular
 	 * backend, so we use the same signal handling.  See equivalent code in

src/backend/postmaster/bgworker.c

@@ -13,7 +13,6 @@
 #include "postgres.h"
 
 #include <unistd.h>
-#include <time.h>
 
 #include "miscadmin.h"
 #include "libpq/pqsignal.h"
@@ -556,16 +555,8 @@ StartBackgroundWorker(void)
 	if (worker == NULL)
 		elog(FATAL, "unable to find bgworker entry");
 
-	/* we are a postmaster subprocess now */
-	IsUnderPostmaster = true;
 	IsBackgroundWorker = true;
 
-	/* reset MyProcPid */
-	MyProcPid = getpid();
-
-	/* record Start Time for logging */
-	MyStartTime = time(NULL);
-
 	/* Identify myself via ps */
 	snprintf(buf, MAXPGPATH, "bgworker: %s", worker->bgw_name);
 	init_ps_display(buf, "", "", "");
@@ -590,15 +581,6 @@ StartBackgroundWorker(void)
 	if (PostAuthDelay > 0)
 		pg_usleep(PostAuthDelay * 1000000L);
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Set up signal handlers.
 	 */

src/backend/postmaster/bgwriter.c

@@ -36,7 +36,6 @@
 
 #include <signal.h>
 #include <sys/time.h>
-#include <time.h>
 #include <unistd.h>
 
 #include "access/xlog.h"
@@ -113,17 +112,6 @@ BackgroundWriterMain(void)
 	MemoryContext bgwriter_context;
 	bool		prev_hibernate;
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (bgwriter probably never has any
-	 * child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Properly accept or ignore signals the postmaster might send us.
 	 *

src/backend/postmaster/checkpointer.c

@@ -196,17 +196,6 @@ CheckpointerMain(void)
 
 	CheckpointerShmem->checkpointer_pid = MyProcPid;
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (checkpointer probably never has
-	 * any child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Properly accept or ignore signals the postmaster might send us
 	 *

src/backend/postmaster/pgarch.c

@@ -157,12 +157,11 @@ pgarch_start(void)
 #ifndef EXEC_BACKEND
 		case 0:
 			/* in postmaster child ... */
+			InitPostmasterChild();
+
 			/* Close the postmaster's sockets */
 			ClosePostmasterPorts(false);
 
-			/* Lose the postmaster's on-exit routines */
-			on_exit_reset();
-
 			/* Drop our connection to postmaster's shared memory, as well */
 			dsm_detach_all();
 			PGSharedMemoryDetach();
@@ -221,21 +220,6 @@ pgarch_forkexec(void)
 NON_EXEC_STATIC void
 PgArchiverMain(int argc, char *argv[])
 {
-	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
-
-	MyProcPid = getpid();		/* reset MyProcPid */
-
-	MyStartTime = time(NULL);	/* record Start Time for logging */
-
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	InitializeLatchSupport();	/* needed for latch waits */
 
 	InitLatch(&mainloop_latch); /* initialize latch used in main loop */

src/backend/postmaster/pgstat.c

@@ -695,12 +695,11 @@ pgstat_start(void)
 #ifndef EXEC_BACKEND
 		case 0:
 			/* in postmaster child ... */
+			InitPostmasterChild();
+
 			/* Close the postmaster's sockets */
 			ClosePostmasterPorts(false);
 
-			/* Lose the postmaster's on-exit routines */
-			on_exit_reset();
-
 			/* Drop our connection to postmaster's shared memory, as well */
 			dsm_detach_all();
 			PGSharedMemoryDetach();
@@ -3152,23 +3151,6 @@ PgstatCollectorMain(int argc, char *argv[])
 	PgStat_Msg	msg;
 	int			wr;
 
-	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
-
-	MyProcPid = getpid();		/* reset MyProcPid */
-
-	MyStartTime = time(NULL);	/* record Start Time for logging */
-
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (pgstat probably never has any
-	 * child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	InitializeLatchSupport();	/* needed for latch waits */
 
 	/* Initialize private latch for use by signal handlers */

src/backend/postmaster/postmaster.c

@@ -3811,19 +3811,8 @@ BackendStartup(Port *port)
 	{
 		free(bn);
 
-		/*
-		 * Let's clean up ourselves as the postmaster child, and close the
-		 * postmaster's listen sockets.  (In EXEC_BACKEND case this is all
-		 * done in SubPostmasterMain.)
-		 */
-		IsUnderPostmaster = true;		/* we are a postmaster subprocess now */
-
-		MyProcPid = getpid();	/* reset MyProcPid */
-
-		MyStartTime = time(NULL);
-
-		/* We don't want the postmaster's proc_exit() handlers */
-		on_exit_reset();
+		/* Detangle from postmaster */
+		InitPostmasterChild();
 
 		/* Close the postmaster's sockets */
 		ClosePostmasterPorts(false);
@@ -3953,16 +3942,6 @@ BackendInitialize(Port *port)
 	pq_init();					/* initialize libpq to talk to client */
 	whereToSendOutput = DestRemote;		/* now safe to ereport to client */
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (We do this now on the off chance
-	 * that something might spawn a child process during authentication.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * We arrange for a simple exit(1) if we receive SIGTERM or SIGQUIT or
 	 * timeout while trying to collect the startup packet.  Otherwise the
@@ -4515,30 +4494,13 @@ SubPostmasterMain(int argc, char *argv[])
 {
 	Port		port;
 
-	/* Do this sooner rather than later... */
-	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
-
-	MyProcPid = getpid();		/* reset MyProcPid */
-
-	MyStartTime = time(NULL);
-
-	/*
-	 * make sure stderr is in binary mode before anything can possibly be
-	 * written to it, in case it's actually the syslogger pipe, so the pipe
-	 * chunking protocol isn't disturbed. Non-logpipe data gets translated on
-	 * redirection (e.g. via pg_ctl -l) anyway.
-	 */
-#ifdef WIN32
-	_setmode(fileno(stderr), _O_BINARY);
-#endif
-
-	/* Lose the postmaster's on-exit routines (really a no-op) */
-	on_exit_reset();
-
 	/* In EXEC_BACKEND case we will not have inherited these settings */
 	IsPostmasterEnvironment = true;
 	whereToSendOutput = DestNone;
 
+	/* Setup as postmaster child */
+	InitPostmasterChild();
+
 	/* Setup essential subsystems (to ensure elog() behaves sanely) */
 	InitializeGUCOptions();
 
@@ -4718,6 +4680,8 @@ SubPostmasterMain(int argc, char *argv[])
 		/* do this as early as possible; in particular, before InitProcess() */
 		IsBackgroundWorker = true;
 
+		InitPostmasterChild();
+
 		/* Close the postmaster's sockets */
 		ClosePostmasterPorts(false);
 
@@ -5138,14 +5102,11 @@ StartChildProcess(AuxProcType type)
 
 	if (pid == 0)				/* child */
 	{
-		IsUnderPostmaster = true;		/* we are a postmaster subprocess now */
+		InitPostmasterChild();
 
 		/* Close the postmaster's sockets */
 		ClosePostmasterPorts(false);
 
-		/* Lose the postmaster's on-exit routines and port connections */
-		on_exit_reset();
-
 		/* Release postmaster's working memory context */
 		MemoryContextSwitchTo(TopMemoryContext);
 		MemoryContextDelete(PostmasterContext);
@@ -5424,12 +5385,11 @@ do_start_bgworker(RegisteredBgWorker *rw)
 #ifndef EXEC_BACKEND
 		case 0:
 			/* in postmaster child ... */
+			InitPostmasterChild();
+
 			/* Close the postmaster's sockets */
 			ClosePostmasterPorts(false);
 
-			/* Lose the postmaster's on-exit routines */
-			on_exit_reset();
-
 			/* Do NOT release postmaster's working memory context */
 
 			MyBgworkerEntry = &rw->rw_worker;

src/backend/postmaster/startup.c

@@ -177,15 +177,6 @@ HandleStartupProcInterrupts(void)
 void
 StartupProcessMain(void)
 {
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Properly accept or ignore signals the postmaster might send us.
 	 */

src/backend/postmaster/syslogger.c

@@ -164,11 +164,6 @@ SysLoggerMain(int argc, char *argv[])
 	int			currentLogRotationAge;
 	pg_time_t	now;
 
-	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
-
-	MyProcPid = getpid();		/* reset MyProcPid */
-
-	MyStartTime = time(NULL);	/* set our start time in case we call elog */
 	now = MyStartTime;
 
 #ifdef EXEC_BACKEND
@@ -236,18 +231,8 @@ SysLoggerMain(int argc, char *argv[])
 	syslogPipe[1] = 0;
 #endif
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (syslogger probably never has any
-	 * child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
+	InitializeLatchSupport();		/* needed for latch waits */
 
-	InitializeLatchSupport();	/* needed for latch waits */
 
 	/* Initialize private latch for use by signal handlers */
 	InitLatch(&sysLoggerLatch);
@@ -609,12 +594,11 @@ SysLogger_Start(void)
 #ifndef EXEC_BACKEND
 		case 0:
 			/* in postmaster child ... */
+			InitPostmasterChild();
+
 			/* Close the postmaster's sockets */
 			ClosePostmasterPorts(true);
 
-			/* Lose the postmaster's on-exit routines */
-			on_exit_reset();
-
 			/* Drop our connection to postmaster's shared memory, as well */
 			dsm_detach_all();
 			PGSharedMemoryDetach();

src/backend/postmaster/walwriter.c

@@ -42,8 +42,6 @@
 #include "postgres.h"
 
 #include <signal.h>
-#include <sys/time.h>
-#include <time.h>
 #include <unistd.h>
 
 #include "access/xlog.h"
@@ -101,17 +99,6 @@ WalWriterMain(void)
 	int			left_till_hibernate;
 	bool		hibernating;
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (walwriter probably never has any
-	 * child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/*
 	 * Properly accept or ignore signals the postmaster might send us
 	 *

src/backend/replication/walreceiver.c

@@ -256,17 +256,6 @@ WalReceiverMain(void)
 
 	OwnLatch(&walrcv->latch);
 
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.  (walreceiver probably never has
-	 * any child processes, but for consistency we make all postmaster child
-	 * processes do this.)
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
 	/* Properly accept or ignore signals the postmaster might send us */
 	pqsignal(SIGHUP, WalRcvSigHupHandler);		/* set flag to read config
 												 * file */

src/backend/tcop/postgres.c

@@ -22,7 +22,6 @@
 #include <fcntl.h>
 #include <limits.h>
 #include <signal.h>
-#include <time.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #ifdef HAVE_SYS_SELECT_H
@@ -3536,30 +3535,12 @@ PostgresMain(int argc, char *argv[],
 	sigjmp_buf	local_sigjmp_buf;
 	volatile bool send_ready_for_query = true;
 
-	/*
-	 * Initialize globals (already done if under postmaster, but not if
-	 * standalone).
-	 */
+	/* Initialize startup process environment if necessary. */
 	if (!IsUnderPostmaster)
-	{
-		MyProcPid = getpid();
-
-		MyStartTime = time(NULL);
-	}
+		InitStandaloneProcess(argv[0]);
 
 	SetProcessingMode(InitProcessing);
 
-	/* Compute paths, if we didn't inherit them from postmaster */
-	if (my_exec_path[0] == '\0')
-	{
-		if (find_my_exec(argv[0], my_exec_path) < 0)
-			elog(FATAL, "%s: could not locate my own executable path",
-				 argv[0]);
-	}
-
-	if (pkglib_path[0] == '\0')
-		get_pkglib_path(my_exec_path, pkglib_path);
-
 	/*
 	 * Set default values for command-line options.
 	 */
@@ -3589,11 +3570,6 @@ PostgresMain(int argc, char *argv[],
 			proc_exit(1);
 	}
 
-	/*
-	 * You might expect to see a setsid() call here, but it's not needed,
-	 * because if we are under a postmaster then BackendInitialize() did it.
-	 */
-
 	/*
 	 * Set up signal handlers and masks.
 	 *

src/backend/utils/init/miscinit.c

@@ -16,9 +16,11 @@
 
 #include <sys/param.h>
 #include <signal.h>
+#include <time.h>
 #include <sys/file.h>
 #include <sys/stat.h>
 #include <sys/time.h>
+#include <sys/types.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <grp.h>
@@ -160,6 +162,70 @@ static int	SecurityRestrictionContext = 0;
 /* We also remember if a SET ROLE is currently active */
 static bool SetRoleIsActive = false;
 
+/*
+ * Initialize the basic environment for a postmaster child
+ *
+ * Should be called as early as possible after the child's startup.
+ */
+void
+InitPostmasterChild(void)
+{
+	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
+
+	MyProcPid = getpid();		/* reset MyProcPid */
+
+	MyStartTime = time(NULL);	/* set our start time in case we call elog */
+
+	/*
+	 * make sure stderr is in binary mode before anything can possibly be
+	 * written to it, in case it's actually the syslogger pipe, so the pipe
+	 * chunking protocol isn't disturbed. Non-logpipe data gets translated on
+	 * redirection (e.g. via pg_ctl -l) anyway.
+	 */
+#ifdef WIN32
+	_setmode(fileno(stderr), _O_BINARY);
+#endif
+
+	/* We don't want the postmaster's proc_exit() handlers */
+	on_exit_reset();
+
+	/*
+	 * If possible, make this process a group leader, so that the postmaster
+	 * can signal any child processes too. Not all processes will have
+	 * children, but for consistency we , but for consistency we make all
+	 * postmaster child processes do this.
+	 */
+#ifdef HAVE_SETSID
+	if (setsid() < 0)
+		elog(FATAL, "setsid() failed: %m");
+#endif
+}
+
+/*
+ * Initialize the basic environment for a standalone process.
+ *
+ * argv0 has to be suitable to find the program's executable.
+ */
+void
+InitStandaloneProcess(const char *argv0)
+{
+	Assert(!IsPostmasterEnvironment);
+
+	MyProcPid = getpid();		/* reset MyProcPid */
+
+	MyStartTime = time(NULL);	/* set our start time in case we call elog */
+
+	/* Compute paths, no postmaster to inherit from */
+	if (my_exec_path[0] == '\0')
+	{
+		if (find_my_exec(argv0, my_exec_path) < 0)
+			elog(FATAL, "%s: could not locate my own executable path",
+				 argv0);
+	}
+
+	if (pkglib_path[0] == '\0')
+		get_pkglib_path(my_exec_path, pkglib_path);
+}
 
 /*
  * GetUserId - get the current effective user ID.

src/include/miscadmin.h

@@ -277,6 +277,9 @@ extern int	trace_recovery(int trace_level);
 extern char *DatabasePath;
 
 /* now in utils/init/miscinit.c */
+extern void InitPostmasterChild(void);
+extern void InitStandaloneProcess(const char *argv0);
+
 extern void SetDatabasePath(const char *path);
 
 extern char *GetUserNameFromId(Oid roleid);