postmaster.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

				/* Multiplexed backends no longer supported. */
				break;
			case 'M':

				/*
				 * ignore this flag.  This may be passed in because the
				 * program was run as 'postgres -M' instead of 'postmaster'
				 */
				break;
			case 'N':
				/* The max number of backends to start. */
				SetConfigOption("max_connections", optarg, PGC_POSTMASTER, PGC_S_ARGV);
				break;
			case 'n':
				/* Don't reinit shared mem after abnormal exit */
				Reinit = false;
				break;
			case 'o':

				/*
				 * Other options to pass to the backend on the command line
				 */
				snprintf(ExtraOptions + strlen(ExtraOptions),
						 sizeof(ExtraOptions) - strlen(ExtraOptions),
						 " %s", optarg);
				break;
			case 'p':
				SetConfigOption("port", optarg, PGC_POSTMASTER, PGC_S_ARGV);
				break;
			case 'S':

				/*
				 * Start in 'S'ilent mode (disassociate from controlling tty).
				 * You may also think of this as 'S'ysV mode since it's most
				 * badly needed on SysV-derived systems like SVR4 and HP-UX.
				 */
				SetConfigOption("silent_mode", "true", PGC_POSTMASTER, PGC_S_ARGV);
				break;
			case 's':

				/*
				 * In the event that some backend dumps core, send SIGSTOP,
				 * rather than SIGQUIT, to all its peers.  This lets the wily
				 * post_hacker collect core dumps from everyone.
				 */
				SendStop = true;
				break;
			case 'c':
			case '-':
				{
					char	   *name,
							   *value;

					ParseLongOption(optarg, &name, &value);
					if (!value)
					{
						if (opt == '-')
							ereport(ERROR,
									(errcode(ERRCODE_SYNTAX_ERROR),
									 errmsg("--%s requires a value",
											optarg)));
						else
							ereport(ERROR,
									(errcode(ERRCODE_SYNTAX_ERROR),
									 errmsg("-c %s requires a value",
											optarg)));
					}

					SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
					free(name);
					if (value)
						free(value);
					break;
				}

			default:
				write_stderr("Try \"%s --help\" for more information.\n",
							 progname);
				ExitPostmaster(1);
		}
	}

	/*
	 * Postmaster accepts no non-option switch arguments.
	 */
	if (optind < argc)
	{
		write_stderr("%s: invalid argument: \"%s\"\n",
					 progname, argv[optind]);
		write_stderr("Try \"%s --help\" for more information.\n",
					 progname);
		ExitPostmaster(1);
	}

#ifdef EXEC_BACKEND
	/* Locate executable backend before we change working directory */
	if (find_other_exec(argv[0], "postgres", PG_VERSIONSTR,
						postgres_exec_path) < 0)
		ereport(FATAL,
				(errmsg("%s: could not locate matching postgres executable",
						progname)));
#endif

	/*
	 * Locate the proper configuration files and data directory, and read
	 * postgresql.conf for the first time.
	 */
	if (!SelectConfigFiles(userDoption, progname))
		ExitPostmaster(2);

	/* Verify that DataDir looks reasonable */
	checkDataDir();

	/* And switch working directory into it */
	ChangeToDataDir();

	/*
	 * Check for invalid combinations of GUC settings.
	 */
	if (NBuffers < 2 * MaxBackends || NBuffers < 16)
	{
		/*
		 * Do not accept -B so small that backends are likely to starve for
		 * lack of buffers.  The specific choices here are somewhat arbitrary.
		 */
		write_stderr("%s: the number of buffers (-B) must be at least twice the number of allowed connections (-N) and at least 16\n", progname);
		ExitPostmaster(1);
	}

	if (ReservedBackends >= MaxBackends)
	{
		write_stderr("%s: superuser_reserved_connections must be less than max_connections\n", progname);
		ExitPostmaster(1);
	}

	/*
	 * Other one-time internal sanity checks can go here, if they are fast.
	 * (Put any slow processing further down, after postmaster.pid creation.)
	 */
	if (!CheckDateTokenTables())
	{
		write_stderr("%s: invalid datetoken tables, please fix\n", progname);
		ExitPostmaster(1);
	}

	/*
	 * Now that we are done processing the postmaster arguments, reset
	 * getopt(3) library so that it will work correctly in subprocesses.
	 */
	optind = 1;
#ifdef HAVE_INT_OPTRESET
	optreset = 1;				/* some systems need this too */
#endif

	/* For debugging: display postmaster environment */
	{
		extern char **environ;
		char	  **p;

		ereport(DEBUG3,
				(errmsg_internal("%s: PostmasterMain: initial environ dump:",
								 progname)));
		ereport(DEBUG3,
			 (errmsg_internal("-----------------------------------------")));
		for (p = environ; *p; ++p)
			ereport(DEBUG3,
					(errmsg_internal("\t%s", *p)));
		ereport(DEBUG3,
			 (errmsg_internal("-----------------------------------------")));
	}

	/*
	 * Fork away from controlling terminal, if -S specified.
	 *
	 * Must do this before we grab any interlock files, else the interlocks
	 * will show the wrong PID.
	 */
	if (SilentMode)
		pmdaemonize();

	/*
	 * Create lockfile for data directory.
	 *
	 * We want to do this before we try to grab the input sockets, because the
	 * data directory interlock is more reliable than the socket-file
	 * interlock (thanks to whoever decided to put socket files in /tmp :-().
	 * For the same reason, it's best to grab the TCP socket(s) before the
	 * Unix socket.
	 */
	CreateDataDirLockFile(true);

	/*
	 * If timezone is not set, determine what the OS uses.	(In theory this
	 * should be done during GUC initialization, but because it can take as
	 * much as several seconds, we delay it until after we've created the
	 * postmaster.pid file.  This prevents problems with boot scripts that
	 * expect the pidfile to appear quickly.)
	 */
	pg_timezone_initialize();

	/*
	 * Initialize SSL library, if specified.
	 */
#ifdef USE_SSL
	if (EnableSSL)
		secure_initialize();
#endif

	/*
	 * process any libraries that should be preloaded and optionally
	 * pre-initialized
	 */
	if (preload_libraries_string)
		process_preload_libraries(preload_libraries_string);

	/*
	 * Remove old temporary files.	At this point there can be no other
	 * Postgres processes running in this directory, so this should be safe.
	 */
	RemovePgTempFiles();

	/*
	 * Establish input sockets.
	 */
	for (i = 0; i < MAXLISTEN; i++)
		ListenSocket[i] = -1;

	if (ListenAddresses)
	{
		char	   *rawstring;
		List	   *elemlist;
		ListCell   *l;
		int			success = 0;

		/* Need a modifiable copy of ListenAddresses */
		rawstring = pstrdup(ListenAddresses);

		/* Parse string into list of identifiers */
		if (!SplitIdentifierString(rawstring, ',', &elemlist))
		{
			/* syntax error in list */
			ereport(FATAL,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("invalid list syntax for \"listen_addresses\"")));
		}

		foreach(l, elemlist)
		{
			char	   *curhost = (char *) lfirst(l);

			if (strcmp(curhost, "*") == 0)
				status = StreamServerPort(AF_UNSPEC, NULL,
										  (unsigned short) PostPortNumber,
										  UnixSocketDir,
										  ListenSocket, MAXLISTEN);
			else
				status = StreamServerPort(AF_UNSPEC, curhost,
										  (unsigned short) PostPortNumber,
										  UnixSocketDir,
										  ListenSocket, MAXLISTEN);
			if (status == STATUS_OK)
				success++;
			else
				ereport(WARNING,
						(errmsg("could not create listen socket for \"%s\"",
								curhost)));
		}

		if (!success && list_length(elemlist))
			ereport(FATAL,
					(errmsg("could not create any TCP/IP sockets")));

		list_free(elemlist);
		pfree(rawstring);
	}

#ifdef USE_BONJOUR
	/* Register for Bonjour only if we opened TCP socket(s) */
	if (ListenSocket[0] != -1 && bonjour_name != NULL)
	{
		DNSServiceRegistrationCreate(bonjour_name,
									 "_postgresql._tcp.",
									 "",
									 htons(PostPortNumber),
									 "",
									 (DNSServiceRegistrationReply) reg_reply,
									 NULL);
	}
#endif

#ifdef HAVE_UNIX_SOCKETS
	status = StreamServerPort(AF_UNIX, NULL,
							  (unsigned short) PostPortNumber,
							  UnixSocketDir,
							  ListenSocket, MAXLISTEN);
	if (status != STATUS_OK)
		ereport(WARNING,
				(errmsg("could not create Unix-domain socket")));
#endif

	/*
	 * check that we have some socket to listen on
	 */
	if (ListenSocket[0] == -1)
		ereport(FATAL,
				(errmsg("no socket created for listening")));

	/*
	 * Set up shared memory and semaphores.
	 */
	reset_shared(PostPortNumber);

	/*
	 * Estimate number of openable files.  This must happen after setting up
	 * semaphores, because on some platforms semaphores count as open files.
	 */
	set_max_safe_fds();

	/*
	 * Initialize the list of active backends.
	 */
	BackendList = DLNewList();

#ifdef WIN32

	/*
	 * Initialize the child pid/HANDLE arrays for signal handling.
	 */
	win32_childPIDArray = (pid_t *)
		malloc(mul_size(NUM_BACKENDARRAY_ELEMS, sizeof(pid_t)));
	win32_childHNDArray = (HANDLE *)
		malloc(mul_size(NUM_BACKENDARRAY_ELEMS, sizeof(HANDLE)));
	if (!win32_childPIDArray || !win32_childHNDArray)
		ereport(FATAL,
				(errcode(ERRCODE_OUT_OF_MEMORY),
				 errmsg("out of memory")));

	/*
	 * Set up a handle that child processes can use to check whether the
	 * postmaster is still running.
	 */
	if (DuplicateHandle(GetCurrentProcess(),
						GetCurrentProcess(),
						GetCurrentProcess(),
						&PostmasterHandle,
						0,
						TRUE,
						DUPLICATE_SAME_ACCESS) == 0)
		ereport(FATAL,
				(errmsg_internal("could not duplicate postmaster handle: error code %d",
								 (int) GetLastError())));
#endif

	/*
	 * Record postmaster options.  We delay this till now to avoid recording
	 * bogus options (eg, NBuffers too high for available memory).
	 */
	if (!CreateOptsFile(argc, argv, my_exec_path))
		ExitPostmaster(1);

#ifdef EXEC_BACKEND
	write_nondefault_variables(PGC_POSTMASTER);
#endif

	/*
	 * Write the external PID file if requested
	 */
	if (external_pid_file)
	{
		FILE	   *fpidfile = fopen(external_pid_file, "w");

		if (fpidfile)
		{
			fprintf(fpidfile, "%d\n", MyProcPid);
			fclose(fpidfile);
			/* Should we remove the pid file on postmaster exit? */
		}
		else
			write_stderr("%s: could not write external PID file \"%s\": %s\n",
						 progname, external_pid_file, strerror(errno));
	}

	/*
	 * Set up signal handlers for the postmaster process.
	 *
	 * CAUTION: when changing this list, check for side-effects on the signal
	 * handling setup of child processes.  See tcop/postgres.c,
	 * bootstrap/bootstrap.c, postmaster/bgwriter.c, postmaster/autovacuum.c,
	 * postmaster/pgarch.c, postmaster/pgstat.c, and postmaster/syslogger.c.
	 */
	pqinitmask();
	PG_SETMASK(&BlockSig);

	pqsignal(SIGHUP, SIGHUP_handler);	/* reread config file and have
										 * children do same */
	pqsignal(SIGINT, pmdie);	/* send SIGTERM and shut down */
	pqsignal(SIGQUIT, pmdie);	/* send SIGQUIT and die */
	pqsignal(SIGTERM, pmdie);	/* wait for children and shut down */
	pqsignal(SIGALRM, SIG_IGN); /* ignored */
	pqsignal(SIGPIPE, SIG_IGN); /* ignored */
	pqsignal(SIGUSR1, sigusr1_handler); /* message from child process */
	pqsignal(SIGUSR2, dummy_handler);	/* unused, reserve for children */
	pqsignal(SIGCHLD, reaper);	/* handle child termination */
	pqsignal(SIGTTIN, SIG_IGN); /* ignored */
	pqsignal(SIGTTOU, SIG_IGN); /* ignored */
	/* ignore SIGXFSZ, so that ulimit violations work like disk full */
#ifdef SIGXFSZ
	pqsignal(SIGXFSZ, SIG_IGN); /* ignored */
#endif

	/*
	 * If enabled, start up syslogger collection subprocess
	 */
	SysLoggerPID = SysLogger_Start();

	/*
	 * Reset whereToSendOutput from DestDebug (its starting state) to
	 * DestNone. This stops ereport from sending log messages to stderr unless
	 * Log_destination permits.  We don't do this until the postmaster is
	 * fully launched, since startup failures may as well be reported to
	 * stderr.
	 */
	whereToSendOutput = DestNone;

	/*
	 * Initialize the statistics collector stuff
	 */
	pgstat_init();

	/*
	 * Load configuration files for client authentication.
	 */
	load_hba();
	load_ident();

	/*
	 * We're ready to rock and roll...
	 */
	StartupPID = StartupDataBase();

	/*
	 * Remember postmaster startup time
	 */
	PgStartTime = GetCurrentTimestamp();

	/*
	 * Initialize the autovacuum daemon
	 */
	autovac_init();

	status = ServerLoop();

	/*
	 * ServerLoop probably shouldn't ever return, but if it does, close down.
	 */
	ExitPostmaster(status != STATUS_OK);

	return 0;					/* not reached */
}


/*
 * Validate the proposed data directory
 */
static void
checkDataDir(void)
{
	char		path[MAXPGPATH];
	FILE	   *fp;
	struct stat stat_buf;

	Assert(DataDir);

	if (stat(DataDir, &stat_buf) != 0)
	{
		if (errno == ENOENT)
			ereport(FATAL,
					(errcode_for_file_access(),
					 errmsg("data directory \"%s\" does not exist",
							DataDir)));
		else
			ereport(FATAL,
					(errcode_for_file_access(),
				 errmsg("could not read permissions of directory \"%s\": %m",
						DataDir)));
	}

	/*
	 * Check that the directory belongs to my userid; if not, reject.
	 *