Improve pg_ctl's message for shutdown after recovery.

If pg_ctl tries to start the postmaster, but the postmaster shuts down
because it completed a point-in-time recovery, pg_ctl used to report
a message that indicated a failure.  It's not really a failure, so
instead say "server shut down because of recovery target settings".

Zhao Junwang, Crisp Lee, Laurenz Albe

Discussion: https://postgr.es/m/CAGHPtV7GttPZ-HvxZuYRy70jLGQMEm5=LQc4fKGa=J74m2VZbg@mail.gmail.com

src/bin/pg_ctl/pg_ctl.c

@@ -45,6 +45,7 @@ typedef enum
 {
 	POSTMASTER_READY,
 	POSTMASTER_STILL_STARTING,
+	POSTMASTER_SHUTDOWN_IN_RECOVERY,
 	POSTMASTER_FAILED,
 } WaitPMResult;
 
@@ -657,17 +658,24 @@ wait_for_postmaster_start(pid_t pm_pid, bool do_checkpoint)
 		 * On Windows, we may be checking the postmaster's parent shell, but
 		 * that's fine for this purpose.
 		 */
-#ifndef WIN32
 		{
+			bool		pm_died;
+#ifndef WIN32
 			int			exitstatus;
 
-			if (waitpid(pm_pid, &exitstatus, WNOHANG) == pm_pid)
-				return POSTMASTER_FAILED;
-		}
+			pm_died = (waitpid(pm_pid, &exitstatus, WNOHANG) == pm_pid);
 #else
-		if (WaitForSingleObject(postmasterProcess, 0) == WAIT_OBJECT_0)
-			return POSTMASTER_FAILED;
+			pm_died = (WaitForSingleObject(postmasterProcess, 0) == WAIT_OBJECT_0);
 #endif
+			if (pm_died)
+			{
+				/* See if postmaster terminated intentionally */
+				if (get_control_dbstate() == DB_SHUTDOWNED_IN_RECOVERY)
+					return POSTMASTER_SHUTDOWN_IN_RECOVERY;
+				else
+					return POSTMASTER_FAILED;
+			}
+		}
 
 		/* Startup still in process; wait, printing a dot once per second */
 		if (i % WAITS_PER_SEC == 0)
@@ -991,6 +999,10 @@ do_start(void)
 							 progname);
 				exit(1);
 				break;
+			case POSTMASTER_SHUTDOWN_IN_RECOVERY:
+				print_msg(_(" done\n"));
+				print_msg(_("server shut down because of recovery target settings\n"));
+				break;
 			case POSTMASTER_FAILED:
 				print_msg(_(" stopped waiting\n"));
 				write_stderr(_("%s: could not start server\n"