text: /*-------------------------------------------------------------------------
   *
   * pg_resetxlog.c
   *	  A utility to "zero out" the xlog when it's corrupt beyond recovery.
   *	  Can also rebuild pg_control if needed.
   *
   * The theory of operation is fairly simple:
   *	  1. Read the existing pg_control (which will include the last
   *		 checkpoint record).  If it is an old format then update to
   *		 current format.
   *	  2. If pg_control is corrupt, attempt to intuit reasonable values,
   *		 by scanning the old xlog if necessary.
   *	  3. Modify pg_control to reflect a "shutdown" state with a checkpoint
   *		 record at the start of xlog.
   *	  4. Flush the existing xlog files and write a new segment with
   *		 just a checkpoint record in it.  The new segment is positioned
   *		 just past the end of the old xlog, so that existing LSNs in
   *		 data pages will appear to be "in the past".
   * This is all pretty straightforward except for the intuition part of
   * step 2 ...
   *
   *
   * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * src/bin/pg_resetxlog/pg_resetxlog.c
   *
   *-------------------------------------------------------------------------
   */
  
  /*
   * We have to use postgres.h not postgres_fe.h here, because there's so much
   * backend-only stuff in the XLOG include files we need.  But we need a
   * frontend-ish environment otherwise.  Hence this ugly hack.
   */
  #define FRONTEND 1
  
  #include "postgres.h"
  
  #include <dirent.h>
  #include <fcntl.h>
  #include <locale.h>
  #include <sys/stat.h>
  #include <sys/time.h>
  #include <time.h>
  #include <unistd.h>
  
  #include "access/transam.h"
  #include "access/tuptoaster.h"
  #include "access/multixact.h"
  #include "access/xlog.h"
  #include "access/xlog_internal.h"
  #include "catalog/catversion.h"
  #include "catalog/pg_control.h"
  #include "common/fe_memutils.h"
  #include "common/restricted_token.h"
  #include "storage/large_object.h"
  #include "pg_getopt.h"
  
  
  static ControlFileData ControlFile;		/* pg_control values */
  static XLogSegNo newXlogSegNo;	/* new XLOG segment # */
  static bool guessed = false;	/* T if we had to guess at any values */
  static const char *progname;
  static uint32 set_xid_epoch = (uint32) -1;
  static TransactionId set_xid = 0;
  static TransactionId set_oldest_commit_ts = 0;
  static TransactionId set_newest_commit_ts = 0;
  static Oid	set_oid = 0;
  static MultiXactId set_mxid = 0;
  static MultiXactOffset set_mxoff = (MultiXactOffset) -1;
  static uint32 minXlogTli = 0;
  static XLogSegNo minXlogSegNo = 0;
  
  static bool ReadControlFile(void);
  static void GuessControlValues(void);
  static void PrintControlValues(bool guessed);
  static void PrintNewControlValues(void);
  static void RewriteControlFile(void);
  static void FindEndOfXLOG(void);
  static void KillExistingXLOG(void);
  static void KillExistingArchiveStatus(void);
  static void WriteEmptyXLOG(void);
  static void usage(void);
  
  
  int
  main(int argc, char *argv[])
  {
  	int			c;
  	bool		force = false;
  	bool		noupdate = false;
  	MultiXactId set_oldestmxid = 0;
  	char	   *endptr;
  	char	   *endptr2;
  	char	   *DataDir = NULL;
  	int			fd;
  
  	set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_resetxlog"));
  
  	progname = get_progname(argv[0]);
  
  	if (argc > 1)
  	{
  		if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
  		{
  			usage();
  			exit(0);
  		}
  		if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
  		{
  			puts("pg_resetxlog (PostgreSQL) " PG_VERSION);
  			exit(0);
  		}
  	}
  
  
  	while ((c = getopt(argc, argv, "c:D:e:fl:m:no:O:x:")) != -1)
  	{
  		switch (c)
  		{
  			case 'D':
  				DataDir = optarg;
  				break;
  
  			case 'f':
  				force = true;
  				break;
  
  			case 'n':
  				noupdate = true;
  				break;
  
  			case 'e':
  				set_xid_epoch = strtoul(optarg, &endptr, 0);
  				if (endptr == optarg || *endptr != '\0')
  				{
  					/*------
  					  translator: the second %s is a command line argument (-e, etc) */
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-e");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				if (set_xid_epoch == -1)
  				{
  					fprintf(stderr, _("%s: transaction ID epoch (-e) must not be -1\n"), progname);
  					exit(1);
  				}
  				break;
  
  			case 'x':
  				set_xid = strtoul(optarg, &endptr, 0);
  				if (endptr == optarg || *endptr != '\0')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-x");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				if (set_xid == 0)
  				{
  					fprintf(stderr, _("%s: transaction ID (-x) must not be 0\n"), progname);
  					exit(1);
  				}
  				break;
  
  			case 'c':
  				set_oldest_commit_ts = strtoul(optarg, &endptr, 0);
  				if (endptr == optarg || *endptr != ',')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-c");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				set_newest_commit_ts = strtoul(endptr + 1, &endptr2, 0);
  				if (endptr2 == endptr + 1 || *endptr2 != '\0')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-c");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  
  				if (set_oldest_commit_ts < 2 &&
  					set_oldest_commit_ts != 0)
  				{
  					fprintf(stderr, _("%s: transaction ID (-c) must be either 0 or greater than or equal to 2\n"), progname);
  					exit(1);
  				}
  
  				if (set_newest_commit_ts < 2 &&
  					set_newest_commit_ts != 0)
  				{
  					fprintf(stderr, _("%s: transaction ID (-c) must be either 0 or greater than or equal to 2\n"), progname);
  					exit(1);
  				}
  				break;
  
  			case 'o':
  				set_oid = strtoul(optarg, &endptr, 0);
  				if (endptr == optarg || *endptr != '\0')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-o");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				if (set_oid == 0)
  				{
  					fprintf(stderr, _("%s: OID (-o) must not be 0\n"), progname);
  					exit(1);
  				}
  				break;
  
  			case 'm':
  				set_mxid = strtoul(optarg, &endptr, 0);
  				if (endptr == optarg || *endptr != ',')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-m");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  
  				set_oldestmxid = strtoul(endptr + 1, &endptr2, 0);
  				if (endptr2 == endptr + 1 || *endptr2 != '\0')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-m");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				if (set_mxid == 0)
  				{
  					fprintf(stderr, _("%s: multitransaction ID (-m) must not be 0\n"), progname);
  					exit(1);
  				}
  
  				/*
  				 * XXX It'd be nice to have more sanity checks here, e.g. so
  				 * that oldest is not wrapped around w.r.t. nextMulti.
  				 */
  				if (set_oldestmxid == 0)
  				{
  					fprintf(stderr, _("%s: oldest multitransaction ID (-m) must not be 0\n"),
  							progname);
  					exit(1);
  				}
  				break;
  
  			case 'O':
  				set_mxoff = strtoul(optarg, &endptr, 0);
  				if (endptr == optarg || *endptr != '\0')
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-O");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				if (set_mxoff == -1)
  				{
  					fprintf(stderr, _("%s: multitransaction offset (-O) must not be -1\n"), progname);
  					exit(1);
  				}
  				break;
  
  			case 'l':
  				if (strspn(optarg, "01234567890ABCDEFabcdef") != XLOG_FNAME_LEN)
  				{
  					fprintf(stderr, _("%s: invalid argument for option %s\n"), progname, "-l");
  					fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  					exit(1);
  				}
  				XLogFromFileName(optarg, &minXlogTli, &minXlogSegNo);
  				break;
  
  			default:
  				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  				exit(1);
  		}
  	}
  
  	if (DataDir == NULL && optind < argc)
  		DataDir = argv[optind++];
  
  	/* Complain if any arguments remain */
  	if (optind < argc)
  	{
  		fprintf(stderr, _("%s: too many command-line arguments (first is \"%s\")\n"),
  				progname, argv[optind]);
  		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
  				progname);
  		exit(1);
  	}
  
  	if (DataDir == NULL)
  	{
  		fprintf(stderr, _("%s: no data directory specified\n"), progname);
  		fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  		exit(1);
  	}
  
  	/*
  	 * Don't allow pg_resetxlog to be run as root, to avoid overwriting the
  	 * ownership of files in the data directory. We need only check for root
  	 * -- any other user won't have sufficient permissions to modify files in
  	 * the data directory.
  	 */
  #ifndef WIN32
  	if (geteuid() == 0)
  	{
  		fprintf(stderr, _("%s: cannot be executed by \"root\"\n"),
  				progname);
  		fprintf(stderr, _("You must run %s as the PostgreSQL superuser.\n"),
  				progname);
  		exit(1);
  	}
  #endif
  
  	get_restricted_token(progname);
  
  	if (chdir(DataDir) < 0)
  	{
  		fprintf(stderr, _("%s: could not change directory to \"%s\": %s\n"),
  				progname, DataDir, strerror(errno));
  		exit(1);
  	}
  
  	/*
  	 * Check for a postmaster lock file --- if there is one, refuse to
  	 * proceed, on grounds we might be interfering with a live installation.
  	 */
  	if ((fd = open("postmaster.pid", O_RDONLY, 0)) < 0)
  	{
  		if (errno != ENOENT)
  		{
  			fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
  					progname, "postmaster.pid", strerror(errno));
  			exit(1);
  		}
  	}
  	else
  	{
  		fprintf(stderr, _("%s: lock file \"%s\" exists\n"
  						  "Is a server running?  If not, delete the lock file and try again.\n"),
  				progname, "postmaster.pid");
  		exit(1);
  	}
  
  	/*
  	 * Attempt to read the existing pg_control file
  	 */
  	if (!ReadControlFile())
  		GuessControlValues();
  
  	/*
  	 * Also look at existing segment files to set up newXlogSegNo
  	 */
  	FindEndOfXLOG();
  
  	/*
  	 * If we're not going to proceed with the reset, print the current control
  	 * file parameters.
  	 */
  	if ((guessed && !force) || noupdate)
  		PrintControlValues(guessed);
  
  	/*
  	 * Adjust fields if required by switches.  (Do this now so that printout,
  	 * if any, includes these values.)
  	 */
  	if (set_xid_epoch != -1)
  		ControlFile.checkPointCopy.nextXidEpoch = set_xid_epoch;
  
  	if (set_xid != 0)
  	{
  		ControlFile.checkPointCopy.nextXid = set_xid;
  
  		/*
  		 * For the moment, just set oldestXid to a value that will force
  		 * immediate autovacuum-for-wraparound.  It's not clear whether adding
  		 * user control of this is useful, so let's just do something that's
  		 * reasonably safe.  The magic constant here corresponds to the
  		 * maximum allowed value of autovacuum_freeze_max_age.
  		 */
  		ControlFile.checkPointCopy.oldestXid = set_xid - 2000000000;
  		if (ControlFile.checkPointCopy.oldestXid < FirstNormalTransactionId)
  			ControlFile.checkPointCopy.oldestXid += FirstNormalTransactionId;
  		ControlFile.checkPointCopy.oldestXidDB = InvalidOid;
  	}
  
  	if (set_oldest_commit_ts != 0)
  		ControlFile.checkPointCopy.oldestCommitTs = set_oldest_commit_ts;
  	if (set_newest_commit_ts != 0)
  		ControlFile.checkPointCopy.newestCommitTs = set_newest_commit_ts;
  
  	if (set_oid != 0)
  		ControlFile.checkPointCopy.nextOid = set_oid;
  
  	if (set_mxid != 0)
  	{
  		ControlFile.checkPointCopy.nextMulti = set_mxid;
  
  		ControlFile.checkPointCopy.oldestMulti = set_oldestmxid;
  		if (ControlFile.checkPointCopy.oldestMulti < FirstMultiXactId)
  			ControlFile.checkPointCopy.oldestMulti += FirstMultiXactId;
  		ControlFile.checkPointCopy.oldestMultiDB = InvalidOid;
  	}
  
  	if (set_mxoff != -1)
  		ControlFile.checkPointCopy.nextMultiOffset = set_mxoff;
  
  	if (minXlogTli > ControlFile.checkPointCopy.ThisTimeLineID)
  	{
  		ControlFile.checkPointCopy.ThisTimeLineID = minXlogTli;
  		ControlFile.checkPointCopy.PrevTimeLineID = minXlogTli;
  	}
  
  	if (minXlogSegNo > newXlogSegNo)
  		newXlogSegNo = minXlogSegNo;
  
  	/*
  	 * If we had to guess anything, and -f was not given, just print the
  	 * guessed values and exit.  Also print if -n is given.
  	 */
  	if ((guessed && !force) || noupdate)
  	{
  		PrintNewControlValues();
  		if (!noupdate)
  		{
  			printf(_("\nIf these values seem acceptable, use -f to force reset.\n"));
  			exit(1);
  		}
  		else
  			exit(0);
  	}
  
  	/*
  	 * Don't reset from a dirty pg_control without -f, either.
  	 */
  	if (ControlFile.state != DB_SHUTDOWNED && !force)
  	{
  		printf(_("The database server was not shut down cleanly.\n"
  			   "Resetting the transaction log might cause data to be lost.\n"
  				 "If you want to proceed anyway, use -f to force reset.\n"));
  		exit(1);
  	}
  
  	/*
  	 * Else, do the dirty deed.
  	 */
  	RewriteControlFile();
  	KillExistingXLOG();
  	KillExistingArchiveStatus();
  	WriteEmptyXLOG();
  
  	printf(_("Transaction log reset\n"));
  	return 0;
  }
  
  
  /*
   * Try to read the existing pg_control file.
   *
   * This routine is also responsible for updating old pg_control versions
   * to the current format.  (Currently we don't do anything of the sort.)
   */
  static bool
  ReadControlFile(void)
  {
  	int			fd;
  	int			len;
  	char	   *buffer;
  	pg_crc32c	crc;
  
  	if ((fd = open(XLOG_CONTROL_FILE, O_RDONLY | PG_BINARY, 0)) < 0)
  	{
  		/*
  		 * If pg_control is not there at all, or we can't read it, the odds
  		 * are we've been handed a bad DataDir path, so give up. User can do
  		 * "touch pg_control" to force us to proceed.
  		 */
  		fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
  				progname, XLOG_CONTROL_FILE, strerror(errno));
  		if (errno == ENOENT)
  			fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
  							  "  touch %s\n"
  							  "and try again.\n"),
  					XLOG_CONTROL_FILE);
  		exit(1);
  	}
  
  	/* Use malloc to ensure we have a maxaligned buffer */
  	buffer = (char *) pg_malloc(PG_CONTROL_SIZE);
  
  	len = read(fd, buffer, PG_CONTROL_SIZE);
  	if (len < 0)
  	{
  		fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
  				progname, XLOG_CONTROL_FILE, strerror(errno));
  		exit(1);
  	}
  	close(fd);
  
  	if (len >= sizeof(ControlFileData) &&
  	  ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
  	{
  		/* Check the CRC. */
  		INIT_CRC32C(crc);
  		COMP_CRC32C(crc,
  					buffer,
  					offsetof(ControlFileData, crc));
  		FIN_CRC32C(crc);
  
  		if (EQ_CRC32C(crc, ((ControlFileData *) buffer)->crc))
  		{
  			/* Valid data... */
  			memcpy(&ControlFile, buffer, sizeof(ControlFile));
  			return true;
  		}
  
  		fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
  				progname);
  		/* We will use the data anyway, but treat it as guessed. */
  		memcpy(&ControlFile, buffer, sizeof(ControlFile));
  		guessed = true;
  		return true;
  	}
  
  	/* Looks like it's a mess. */
  	fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
  			progname);
  	return false;
  }
  
  
  /*
   * Guess at pg_control values when we can't read the old ones.
   */
  static void
  GuessControlValues(void)
  {
  	uint64		sysidentifier;
  	struct timeval tv;
  
  	/*
  	 * Set up a completely default set of pg_control values.
  	 */
  	guessed = true;
  	memset(&ControlFile, 0, sizeof(ControlFile));
  
  	ControlFile.pg_control_version = PG_CONTROL_VERSION;
  	ControlFile.catalog_version_no = CATALOG_VERSION_NO;
  
  	/*
  	 * Create a new unique installation identifier, since we can no longer use
  	 * any old XLOG records.  See notes in xlog.c about the algorithm.
  	 */
  	gettimeofday(&tv, NULL);
  	sysidentifier = ((uint64) tv.tv_sec) << 32;
  	sysidentifier |= ((uint64) tv.tv_usec) << 12;
  	sysidentifier |= getpid() & 0xFFF;
  
  	ControlFile.system_identifier = sysidentifier;
  
  	ControlFile.checkPointCopy.redo = SizeOfXLogLongPHD;
  	ControlFile.checkPointCopy.ThisTimeLineID = 1;
  	ControlFile.checkPointCopy.PrevTimeLineID = 1;
  	ControlFile.checkPointCopy.fullPageWrites = false;
  	ControlFile.checkPointCopy.nextXidEpoch = 0;
  	ControlFile.checkPointCopy.nextXid = FirstNormalTransactionId;
  	ControlFile.checkPointCopy.nextOid = FirstBootstrapObjectId;
  	ControlFile.checkPointCopy.nextMulti = FirstMultiXactId;
  	ControlFile.checkPointCopy.nextMultiOffset = 0;
  	ControlFile.checkPointCopy.oldestXid = FirstNormalTransactionId;
  	ControlFile.checkPointCopy.oldestXidDB = InvalidOid;
  	ControlFile.checkPointCopy.oldestMulti = FirstMultiXactId;
  	ControlFile.checkPointCopy.oldestMultiDB = InvalidOid;
  	ControlFile.checkPointCopy.time = (pg_time_t) time(NULL);
  	ControlFile.checkPointCopy.oldestActiveXid = InvalidTransactionId;
  
  	ControlFile.state = DB_SHUTDOWNED;
  	ControlFile.time = (pg_time_t) time(NULL);
  	ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
  	ControlFile.unloggedLSN = 1;
  
  	/* minRecoveryPoint, backupStartPoint and backupEndPoint can be left zero */
  
  	ControlFile.wal_level = WAL_LEVEL_MINIMAL;
  	ControlFile.wal_log_hints = false;
  	ControlFile.track_commit_timestamp = false;
  	ControlFile.MaxConnections = 100;
  	ControlFile.max_worker_processes = 8;
  	ControlFile.max_prepared_xacts = 0;
  	ControlFile.max_locks_per_xact = 64;
  
  	ControlFile.maxAlign = MAXIMUM_ALIGNOF;
  	ControlFile.floatFormat = FLOATFORMAT_VALUE;
  	ControlFile.blcksz = BLCKSZ;
  	ControlFile.relseg_size = RELSEG_SIZE;
  	ControlFile.xlog_blcksz = XLOG_BLCKSZ;
  	ControlFile.xlog_seg_size = XLOG_SEG_SIZE;
  	ControlFile.nameDataLen = NAMEDATALEN;
  	ControlFile.indexMaxKeys = INDEX_MAX_KEYS;
  	ControlFile.toast_max_chunk_size = TOAST_MAX_CHUNK_SIZE;
  	ControlFile.loblksize = LOBLKSIZE;
  #ifdef HAVE_INT64_TIMESTAMP
  	ControlFile.enableIntTimes = true;
  #else
  	ControlFile.enableIntTimes = false;
  #endif
  	ControlFile.float4ByVal = FLOAT4PASSBYVAL;
  	ControlFile.float8ByVal = FLOAT8PASSBYVAL;
  
  	/*
  	 * XXX eventually, should try to grovel through old XLOG to develop more
  	 * accurate values for TimeLineID, nextXID, etc.
  	 */
  }
  
  
  /*
   * Print the guessed pg_control values when we had to guess.
   *
   * NB: this display should be just those fields that will not be
   * reset by RewriteControlFile().
   */
  static void
  PrintControlValues(bool guessed)
  {
  	char		sysident_str[32];
  
  	if (guessed)
  		printf(_("Guessed pg_control values:\n\n"));
  	else
  		printf(_("Current pg_control values:\n\n"));
  
  	/*
  	 * Format system_identifier separately to keep platform-dependent format
  	 * code out of the translatable message string.
  	 */
  	snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
  			 ControlFile.system_identifier);
  
  	printf(_("pg_control version number:            %u\n"),
  		   ControlFile.pg_control_version);
  	printf(_("Catalog version number:               %u\n"),
  		   ControlFile.catalog_version_no);
  	printf(_("Database system identifier:           %s\n"),
  		   sysident_str);
  	printf(_("Latest checkpoint's TimeLineID:       %u\n"),
  		   ControlFile.checkPointCopy.ThisTimeLineID);
  	printf(_("Latest checkpoint's full_page_writes: %s\n"),
  		   ControlFile.checkPointCopy.fullPageWrites ? _("on") : _("off"));
  	printf(_("Latest checkpoint's NextXID:          %u/%u\n"),
  		   ControlFile.checkPointCopy.nextXidEpoch,
  		   ControlFile.checkPointCopy.nextXid);
  	printf(_("Latest checkpoint's NextOID:          %u\n"),
  		   ControlFile.checkPointCopy.nextOid);
  	printf(_("Latest checkpoint's NextMultiXactId:  %u\n"),
  		   ControlFile.checkPointCopy.nextMulti);
  	printf(_("Latest checkpoint's NextMultiOffset:  %u\n"),
  		   ControlFile.checkPointCopy.nextMultiOffset);
  	printf(_("Latest checkpoint's oldestXID:        %u\n"),
  		   ControlFile.checkPointCopy.oldestXid);
  	printf(_("Latest checkpoint's oldestXID's DB:   %u\n"),
  		   ControlFile.checkPointCopy.oldestXidDB);
  	printf(_("Latest checkpoint's oldestActiveXID:  %u\n"),
  		   ControlFile.checkPointCopy.oldestActiveXid);
  	printf(_("Latest checkpoint's oldestMultiXid:   %u\n"),
  		   ControlFile.checkPointCopy.oldestMulti);
  	printf(_("Latest checkpoint's oldestMulti's DB: %u\n"),
  		   ControlFile.checkPointCopy.oldestMultiDB);
  	printf(_("Latest checkpoint's oldest CommitTs:  %u\n"),
  		   ControlFile.checkPointCopy.oldestCommitTs);
  	printf(_("Latest checkpoint's newest CommitTs:  %u\n"),
  		   ControlFile.checkPointCopy.newestCommitTs);
  	printf(_("Maximum data alignment:               %u\n"),
  		   ControlFile.maxAlign);
  	/* we don't print floatFormat since can't say much useful about it */
  	printf(_("Database block size:                  %u\n"),
  		   ControlFile.blcksz);
  	printf(_("Blocks per segment of large relation: %u\n"),
  		   ControlFile.relseg_size);
  	printf(_("WAL block size:                       %u\n"),
  		   ControlFile.xlog_blcksz);
  	printf(_("Bytes per WAL segment:                %u\n"),
  		   ControlFile.xlog_seg_size);
  	printf(_("Maximum length of identifiers:        %u\n"),
  		   ControlFile.nameDataLen);
  	printf(_("Maximum columns in an index:          %u\n"),
  		   ControlFile.indexMaxKeys);
  	printf(_("Maximum size of a TOAST chunk:        %u\n"),
  		   ControlFile.toast_max_chunk_size);
  	printf(_("Size of a large-object chunk:         %u\n"),
  		   ControlFile.loblksize);
  	printf(_("Date/time type storage:               %s\n"),
  		   (ControlFile.enableIntTimes ? _("64-bit integers") : _("floating-point numbers")));
  	printf(_("Float4 argument passing:              %s\n"),
  		   (ControlFile.float4ByVal ? _("by value") : _("by reference")));
  	printf(_("Float8 argument passing:              %s\n"),
  		   (ControlFile.float8ByVal ? _("by value") : _("by reference")));
  	printf(_("Data page checksum version:           %u\n"),
  		   ControlFile.data_checksum_version);
  }
  
  
  /*
   * Print the values to be changed.
   */
  static void
  PrintNewControlValues(void)
  {
  	char		fname[MAXFNAMELEN];
  
  	/* This will be always printed in order to keep format same. */
  	printf(_("\n\nValues to be changed:\n\n"));
  
  	XLogFileName(fname, ControlFile.checkPointCopy.ThisTimeLineID, newXlogSegNo);
  	printf(_("First log segment after reset:        %s\n"), fname);
  
  	if (set_mxid != 0)
  	{
  		printf(_("NextMultiXactId:                      %u\n"),
  			   ControlFile.checkPointCopy.nextMulti);
  		printf(_("OldestMultiXid:                       %u\n"),
  			   ControlFile.checkPointCopy.oldestMulti);
  		printf(_("OldestMulti's DB:                     %u\n"),
  			   ControlFile.checkPointCopy.oldestMultiDB);
  	}
  
  	if (set_mxoff != -1)
  	{
  		printf(_("NextMultiOffset:                      %u\n"),
  			   ControlFile.checkPointCopy.nextMultiOffset);
  	}
  
  	if (set_oid != 0)
  	{
  		printf(_("NextOID:                              %u\n"),
  			   ControlFile.checkPointCopy.nextOid);
  	}
  
  	if (set_xid != 0)
  	{
  		printf(_("NextXID:                              %u\n"),
  			   ControlFile.checkPointCopy.nextXid);
  		printf(_("OldestXID:                            %u\n"),
  			   ControlFile.checkPointCopy.oldestXid);
  		printf(_("OldestXID's DB:                       %u\n"),
  			   ControlFile.checkPointCopy.oldestXidDB);
  	}
  
  	if (set_xid_epoch != -1)
  	{
  		printf(_("NextXID epoch:                        %u\n"),
  			   ControlFile.checkPointCopy.nextXidEpoch);
  	}
  
  	if (set_oldest_commit_ts != 0)
  	{
  		printf(_("oldestCommitTs:                       %u\n"),
  			   ControlFile.checkPointCopy.oldestCommitTs);
  	}
  	if (set_newest_commit_ts != 0)
  	{
  		printf(_("newestCommitTs:                       %u\n"),
  			   ControlFile.checkPointCopy.newestCommitTs);
  	}
  }
  
  
  /*
   * Write out the new pg_control file.
   */
  static void
  RewriteControlFile(void)
  {
  	int			fd;
  	char		buffer[PG_CONTROL_SIZE];		/* need not be aligned */
  
  	/*
  	 * Adjust fields as needed to force an empty XLOG starting at
  	 * newXlogSegNo.
  	 */
  	XLogSegNoOffsetToRecPtr(newXlogSegNo, SizeOfXLogLongPHD,
  							ControlFile.checkPointCopy.redo);
  	ControlFile.checkPointCopy.time = (pg_time_t) time(NULL);
  
  	ControlFile.state = DB_SHUTDOWNED;
  	ControlFile.time = (pg_time_t) time(NULL);
  	ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
  	ControlFile.prevCheckPoint = 0;
  	ControlFile.minRecoveryPoint = 0;
  	ControlFile.minRecoveryPointTLI = 0;
  	ControlFile.backupStartPoint = 0;
  	ControlFile.backupEndPoint = 0;
  	ControlFile.backupEndRequired = false;
  
  	/*
  	 * Force the defaults for max_* settings. The values don't really matter
  	 * as long as wal_level='minimal'; the postmaster will reset these fields
  	 * anyway at startup.
  	 */
  	ControlFile.wal_level = WAL_LEVEL_MINIMAL;
  	ControlFile.wal_log_hints = false;
  	ControlFile.track_commit_timestamp = false;
  	ControlFile.MaxConnections = 100;
  	ControlFile.max_worker_processes = 8;
  	ControlFile.max_prepared_xacts = 0;
  	ControlFile.max_locks_per_xact = 64;
  
  	/* Now we can force the recorded xlog seg size to the right thing. */
  	ControlFile.xlog_seg_size = XLogSegSize;
  
  	/* Contents are protected with a CRC */
  	INIT_CRC32C(ControlFile.crc);
  	COMP_CRC32C(ControlFile.crc,
  				(char *) &ControlFile,
  				offsetof(ControlFileData, crc));
  	FIN_CRC32C(ControlFile.crc);
  
  	/*
  	 * We write out PG_CONTROL_SIZE bytes into pg_control, zero-padding the
  	 * excess over sizeof(ControlFileData).  This reduces the odds of
  	 * premature-EOF errors when reading pg_control.  We'll still fail when we
  	 * check the contents of the file, but hopefully with a more specific
  	 * error than "couldn't read pg_control".
  	 */
  	if (sizeof(ControlFileData) > PG_CONTROL_SIZE)
  	{
  		fprintf(stderr,
  				_("%s: internal error -- sizeof(ControlFileData) is too large ... fix PG_CONTROL_SIZE\n"),
  				progname);
  		exit(1);
  	}
  
  	memset(buffer, 0, PG_CONTROL_SIZE);
  	memcpy(buffer, &ControlFile, sizeof(ControlFileData));
  
  	unlink(XLOG_CONTROL_FILE);
  
  	fd = open(XLOG_CONTROL_FILE,
  			  O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
  			  S_IRUSR | S_IWUSR);
  	if (fd < 0)
  	{
  		fprintf(stderr, _("%s: could not create pg_control file: %s\n"),
  				progname, strerror(errno));
  		exit(1);
  	}
  
  	errno = 0;
  	if (write(fd, buffer, PG_CONTROL_SIZE) != PG_CONTROL_SIZE)
  	{
  		/* if write didn't set errno, assume problem is no disk space */
  		if (errno == 0)
  			errno = ENOSPC;
  		fprintf(stderr, _("%s: could not write pg_control file: %s\n"),
  				progname, strerror(errno));
  		exit(1);
  	}
  
  	if (fsync(fd) != 0)
  	{
  		fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
  		exit(1);
  	}
  
  	close(fd);
  }
  
  
  /*
   * Scan existing XLOG files and determine the highest existing WAL address
   *
   * On entry, ControlFile.checkPointCopy.redo and ControlFile.xlog_seg_size
   * are assumed valid (note that we allow the old xlog seg size to differ
   * from what we're using).  On exit, newXlogId and newXlogSeg are set to
   * suitable values for the beginning of replacement WAL (in our seg size).
   */
  static void
  FindEndOfXLOG(void)
  {
  	DIR		   *xldir;
  	struct dirent *xlde;
  	uint64		segs_per_xlogid;
  	uint64		xlogbytepos;
  
  	/*
  	 * Initialize the max() computation using the last checkpoint address from
  	 * old pg_control.  Note that for the moment we are working with segment
  	 * numbering according to the old xlog seg size.
  	 */
  	segs_per_xlogid = (UINT64CONST(0x0000000100000000) / ControlFile.xlog_seg_size);
  	newXlogSegNo = ControlFile.checkPointCopy.redo / ControlFile.xlog_seg_size;
  
  	/*
  	 * Scan the pg_xlog directory to find existing WAL segment files. We
  	 * assume any present have been used; in most scenarios this should be
  	 * conservative, because of xlog.c's attempts to pre-create files.
  	 */
  	xldir = opendir(XLOGDIR);
  	if (xldir == NULL)
  	{
  		fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
  				progname, XLOGDIR, strerror(errno));
  		exit(1);
  	}
  
  	while (errno = 0, (xlde = readdir(xldir)) != NULL)
  	{
  		if (IsXLogFileName(xlde->d_name) ||
  			IsPartialXLogFileName(xlde->d_name))
  		{
  			unsigned int tli,
  						log,
  						seg;
  			XLogSegNo	segno;
  
  			/*
  			 * Note: We don't use XLogFromFileName here, because we want to
  			 * use the segment size from the control file, not the size the
  			 * pg_resetxlog binary was compiled with
  			 */
  			sscanf(xlde->d_name, "%08X%08X%08X", &tli, &log, &seg);
  			segno = ((uint64) log) * segs_per_xlogid + seg;
  
  			/*
  			 * Note: we take the max of all files found, regardless of their
  			 * timelines.  Another possibility would be to ignore files of
  			 * timelines other than the target TLI, but this seems safer.
  			 * Better too large a result than too small...
  			 */
  			if (segno > newXlogSegNo)
  				newXlogSegNo = segno;
  		}
  	}
  
  	if (errno)
  	{
  		fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
  				progname, XLOGDIR, strerror(errno));
  		exit(1);
  	}
  
  	if (closedir(xldir))
  	{
  		fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
  				progname, XLOGDIR, strerror(errno));
  		exit(1);
  	}
  
  	/*
  	 * Finally, convert to new xlog seg size, and advance by one to ensure we
  	 * are in virgin territory.
  	 */
  	xlogbytepos = newXlogSegNo * ControlFile.xlog_seg_size;
  	newXlogSegNo = (xlogbytepos + XLogSegSize - 1) / XLogSegSize;
  	newXlogSegNo++;
  }
  
  
  /*
   * Remove existing XLOG files
   */
  static void
  KillExistingXLOG(void)
  {
  	DIR		   *xldir;
  	struct dirent *xlde;
  	char		path[MAXPGPATH];
  
  	xldir = opendir(XLOGDIR);
  	if (xldir == NULL)
  	{
  		fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
  				progname, XLOGDIR, strerror(errno));
  		exit(1);
  	}
  
  	while (errno = 0, (xlde = readdir(xldir)) != NULL)
  	{
  		if (IsXLogFileName(xlde->d_name) ||
  			IsPartialXLogFileName(xlde->d_name))
  		{
  			snprintf(path, MAXPGPATH, "%s/%s", XLOGDIR, xlde->d_name);
  			if (unlink(path) < 0)
  			{
  				fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
  						progname, path, strerror(errno));
  				exit(1);
  			}
  		}
  	}
  
  	if (errno)
  	{
  		fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
  				progname, XLOGDIR, strerror(errno));
  		exit(1);
  	}
  
  	if (closedir(xldir))
  	{
  		fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
  				progname, XLOGDIR, strerror(errno));
  		exit(1);
  	}
  }
  
  
  /*
   * Remove existing archive status files
   */
  static void
  KillExistingArchiveStatus(void)
  {
  	DIR		   *xldir;
  	struct dirent *xlde;
  	char		path[MAXPGPATH];
  
  #define ARCHSTATDIR XLOGDIR "/archive_status"
  
  	xldir = opendir(ARCHSTATDIR);
  	if (xldir == NULL)
  	{
  		fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
  				progname, ARCHSTATDIR, strerror(errno));
  		exit(1);
  	}
  
  	while (errno = 0, (xlde = readdir(xldir)) != NULL)
  	{
  		if (strspn(xlde->d_name, "0123456789ABCDEF") == XLOG_FNAME_LEN &&
  			(strcmp(xlde->d_name + XLOG_FNAME_LEN, ".ready") == 0 ||
  			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".done") == 0 ||
  			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".partial.ready") == 0 ||
  			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".partial.done") == 0))
  		{
  			snprintf(path, MAXPGPATH, "%s/%s", ARCHSTATDIR, xlde->d_name);
  			if (unlink(path) < 0)
  			{
  				fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
  						progname, path, strerror(errno));
  				exit(1);
  			}
  		}
  	}
  
  	if (errno)
  	{
  		fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
  				progname, ARCHSTATDIR, strerror(errno));
  		exit(1);
  	}
  
  	if (closedir(xldir))
  	{
  		fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
  				progname, ARCHSTATDIR, strerror(errno));
  		exit(1);
  	}
  }
  
  
  /*
   * Write an empty XLOG file, containing only the checkpoint record
   * already set up in ControlFile.
   */
  static void
  WriteEmptyXLOG(void)
  {
  	char	   *buffer;
  	XLogPageHeader page;
  	XLogLongPageHeader longpage;
  	XLogRecord *record;
  	pg_crc32c	crc;
  	char		path[MAXPGPATH];
  	int			fd;
  	int			nbytes;
  	char	   *recptr;
  
  	/* Use malloc() to ensure buffer is MAXALIGNED */
  	buffer = (char *) pg_malloc(XLOG_BLCKSZ);
  	page = (XLogPageHeader) buffer;
  	memset(buffer, 0, XLOG_BLCKSZ);
  
  	/* Set up the XLOG page header */
  	page->xlp_magic = XLOG_PAGE_MAGIC;
  	page->xlp_info = XLP_LONG_HEADER;
  	page->xlp_tli = ControlFile.checkPointCopy.ThisTimeLineID;
  	page->xlp_pageaddr = ControlFile.checkPointCopy.redo - SizeOfXLogLongPHD;
  	longpage = (XLogLongPageHeader) page;
  	longpage->xlp_sysid = ControlFile.system_identifier;
  	longpage->xlp_seg_size = XLogSegSize;
  	longpage->xlp_xlog_blcksz = XLOG_BLCKSZ;
  
  	/* Insert the initial checkpoint record */
  	recptr = (char *) page + SizeOfXLogLongPHD;
  	record = (XLogRecord *) recptr;
  	record->xl_prev = 0;
  	record->xl_xid = InvalidTransactionId;
  	record->xl_tot_len = SizeOfXLogRecord + SizeOfXLogRecordDataHeaderShort + sizeof(CheckPoint);
  	record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
  	record->xl_rmid = RM_XLOG_ID;
  
  	recptr += SizeOfXLogRecord;
  	*(recptr++) = XLR_BLOCK_ID_DATA_SHORT;
  	*(recptr++) = sizeof(CheckPoint);
  	memcpy(recptr, &ControlFile.checkPointCopy,
  		   sizeof(CheckPoint));
  
  	INIT_CRC32C(crc);
  	COMP_CRC32C(crc, ((char *) record) + SizeOfXLogRecord, record->xl_tot_len - SizeOfXLogRecord);
  	COMP_CRC32C(crc, (char *) record, offsetof(XLogRecord, xl_crc));
  	FIN_CRC32C(crc);
  	record->xl_crc = crc;
  
  	/* Write the first page */
  	XLogFilePath(path, ControlFile.checkPointCopy.ThisTimeLineID, newXlogSegNo);
  
  	unlink(path);
  
  	fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
  			  S_IRUSR | S_IWUSR);
  	if (fd < 0)
  	{
  		fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
  				progname, path, strerror(errno));
  		exit(1);
  	}
  
  	errno = 0;
  	if (write(fd, buffer, XLOG_BLCKSZ) != XLOG_BLCKSZ)
  	{
  		/* if write didn't set errno, assume problem is no disk space */
  		if (errno == 0)
  			errno = ENOSPC;
  		fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
  				progname, path, strerror(errno));
  		exit(1);
  	}
  
  	/* Fill the rest of the file with zeroes */
  	memset(buffer, 0, XLOG_BLCKSZ);
  	for (nbytes = XLOG_BLCKSZ; nbytes < XLogSegSize; nbytes += XLOG_BLCKSZ)
  	{
  		errno = 0;
  		if (write(fd, buffer, XLOG_BLCKSZ) != XLOG_BLCKSZ)
  		{
  			if (errno == 0)
  				errno = ENOSPC;
  			fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
  					progname, path, strerror(errno));
  			exit(1);
  		}
  	}
  
  	if (fsync(fd) != 0)
  	{
  		fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
  		exit(1);
  	}
  
  	close(fd);
  }
  
  
  static void
  usage(void)
  {
  	printf(_("%s resets the PostgreSQL transaction log.\n\n"), progname);
  	printf(_("Usage:\n  %s [OPTION]... {[-D] DATADIR}\n\n"), progname);
  	printf(_("Options:\n"));
  	printf(_("  -c XID,XID       set oldest and newest transactions bearing commit timestamp\n"));
  	printf(_("                   (zero in either value means no change)\n"));
  	printf(_("  -e XIDEPOCH      set next transaction ID epoch\n"));
  	printf(_("  -f               force update to be done\n"));
  	printf(_("  -l XLOGFILE      force minimum WAL starting location for new transaction log\n"));
  	printf(_("  -m MXID,MXID     set next and oldest multitransaction ID\n"));
  	printf(_("  -n               no update, just show what would be done (for testing)\n"));
  	printf(_("  -o OID           set next OID\n"));
  	printf(_("  -O OFFSET        set next multitransaction offset\n"));
  	printf(_("  -V, --version    output version information, then exit\n"));
  	printf(_("  -x XID           set next transaction ID\n"));
  	printf(_("  -?, --help       show this help, then exit\n"));
  	printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));
  }
  