granicus.if.org Git - postgresql/blob - src/bin/pg_resetxlog/pg_resetxlog.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_resetxlog.c
   4  *        A utility to "zero out" the xlog when it's corrupt beyond recovery.
   5  *        Can also rebuild pg_control if needed.
   6  *
   7  * The theory of operation is fairly simple:
   8  *        1. Read the existing pg_control (which will include the last
   9  *               checkpoint record).  If it is an old format then update to
  10  *               current format.
  11  *        2. If pg_control is corrupt, attempt to intuit reasonable values,
  12  *               by scanning the old xlog if necessary.
  13  *        3. Modify pg_control to reflect a "shutdown" state with a checkpoint
  14  *               record at the start of xlog.
  15  *        4. Flush the existing xlog files and write a new segment with
  16  *               just a checkpoint record in it.  The new segment is positioned
  17  *               just past the end of the old xlog, so that existing LSNs in
  18  *               data pages will appear to be "in the past".
  19  * This is all pretty straightforward except for the intuition part of
  20  * step 2 ...
  21  *
  22  *
  23  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  24  * Portions Copyright (c) 1994, Regents of the University of California
  25  *
  26  * $PostgreSQL: pgsql/src/bin/pg_resetxlog/pg_resetxlog.c,v 1.53 2006/10/04 00:30:05 momjian Exp $
  27  *
  28  *-------------------------------------------------------------------------
  29  */
  30 #include "postgres.h"
  31
  32 #include <dirent.h>
  33 #include <fcntl.h>
  34 #include <locale.h>
  35 #include <sys/stat.h>
  36 #include <sys/time.h>
  37 #include <time.h>
  38 #include <unistd.h>
  39 #ifdef HAVE_GETOPT_H
  40 #include <getopt.h>
  41 #endif
  42
  43 #include "access/transam.h"
  44 #include "access/multixact.h"
  45 #include "access/xlog_internal.h"
  46 #include "catalog/catversion.h"
  47 #include "catalog/pg_control.h"
  48
  49 extern int      optind;
  50 extern char *optarg;
  51
  52
  53 static ControlFileData ControlFile;             /* pg_control values */
  54 static uint32 newXlogId,
  55                         newXlogSeg;                     /* ID/Segment of new XLOG segment */
  56 static bool guessed = false;    /* T if we had to guess at any values */
  57 static const char *progname;
  58
  59 static bool ReadControlFile(void);
  60 static void GuessControlValues(void);
  61 static void PrintControlValues(bool guessed);
  62 static void RewriteControlFile(void);
  63 static void KillExistingXLOG(void);
  64 static void WriteEmptyXLOG(void);
  65 static void usage(void);
  66
  67
  68 int
  69 main(int argc, char *argv[])
  70 {
  71         int                     c;
  72         bool            force = false;
  73         bool            noupdate = false;
  74         uint32          set_xid_epoch = -1;
  75         TransactionId set_xid = 0;
  76         Oid                     set_oid = 0;
  77         MultiXactId set_mxid = 0;
  78         MultiXactOffset set_mxoff = -1;
  79         uint32          minXlogTli = 0,
  80                                 minXlogId = 0,
  81                                 minXlogSeg = 0;
  82         char       *endptr;
  83         char       *endptr2;
  84         char       *endptr3;
  85         char       *DataDir;
  86         int                     fd;
  87         char            path[MAXPGPATH];
  88
  89         set_pglocale_pgservice(argv[0], "pg_resetxlog");
  90
  91         progname = get_progname(argv[0]);
  92
  93         if (argc > 1)
  94         {
  95                 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
  96                 {
  97                         usage();
  98                         exit(0);
  99                 }
 100                 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
 101                 {
 102                         puts("pg_resetxlog (PostgreSQL) " PG_VERSION);
 103                         exit(0);
 104                 }
 105         }
 106
 107
 108         while ((c = getopt(argc, argv, "fl:m:no:O:x:e:")) != -1)
 109         {
 110                 switch (c)
 111                 {
 112                         case 'f':
 113                                 force = true;
 114                                 break;
 115
 116                         case 'n':
 117                                 noupdate = true;
 118                                 break;
 119
 120                         case 'e':
 121                                 set_xid_epoch = strtoul(optarg, &endptr, 0);
 122                                 if (endptr == optarg || *endptr != '\0')
 123                                 {
 124                                         fprintf(stderr, _("%s: invalid argument for option -e\n"), progname);
 125                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 126                                         exit(1);
 127                                 }
 128                                 if (set_xid_epoch == -1)
 129                                 {
 130                                         fprintf(stderr, _("%s: transaction ID epoch (-e) must not be -1\n"), progname);
 131                                         exit(1);
 132                                 }
 133                                 break;
 134
 135                         case 'x':
 136                                 set_xid = strtoul(optarg, &endptr, 0);
 137                                 if (endptr == optarg || *endptr != '\0')
 138                                 {
 139                                         fprintf(stderr, _("%s: invalid argument for option -x\n"), progname);
 140                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 141                                         exit(1);
 142                                 }
 143                                 if (set_xid == 0)
 144                                 {
 145                                         fprintf(stderr, _("%s: transaction ID (-x) must not be 0\n"), progname);
 146                                         exit(1);
 147                                 }
 148                                 break;
 149
 150                         case 'o':
 151                                 set_oid = strtoul(optarg, &endptr, 0);
 152                                 if (endptr == optarg || *endptr != '\0')
 153                                 {
 154                                         fprintf(stderr, _("%s: invalid argument for option -o\n"), progname);
 155                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 156                                         exit(1);
 157                                 }
 158                                 if (set_oid == 0)
 159                                 {
 160                                         fprintf(stderr, _("%s: OID (-o) must not be 0\n"), progname);
 161                                         exit(1);
 162                                 }
 163                                 break;
 164
 165                         case 'm':
 166                                 set_mxid = strtoul(optarg, &endptr, 0);
 167                                 if (endptr == optarg || *endptr != '\0')
 168                                 {
 169                                         fprintf(stderr, _("%s: invalid argument for option -m\n"), progname);
 170                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 171                                         exit(1);
 172                                 }
 173                                 if (set_mxid == 0)
 174                                 {
 175                                         fprintf(stderr, _("%s: multitransaction ID (-m) must not be 0\n"), progname);
 176                                         exit(1);
 177                                 }
 178                                 break;
 179
 180                         case 'O':
 181                                 set_mxoff = strtoul(optarg, &endptr, 0);
 182                                 if (endptr == optarg || *endptr != '\0')
 183                                 {
 184                                         fprintf(stderr, _("%s: invalid argument for option -O\n"), progname);
 185                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 186                                         exit(1);
 187                                 }
 188                                 if (set_mxoff == -1)
 189                                 {
 190                                         fprintf(stderr, _("%s: multitransaction offset (-O) must not be -1\n"), progname);
 191                                         exit(1);
 192                                 }
 193                                 break;
 194
 195                         case 'l':
 196                                 minXlogTli = strtoul(optarg, &endptr, 0);
 197                                 if (endptr == optarg || *endptr != ',')
 198                                 {
 199                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 200                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 201                                         exit(1);
 202                                 }
 203                                 minXlogId = strtoul(endptr + 1, &endptr2, 0);
 204                                 if (endptr2 == endptr + 1 || *endptr2 != ',')
 205                                 {
 206                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 207                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 208                                         exit(1);
 209                                 }
 210                                 minXlogSeg = strtoul(endptr2 + 1, &endptr3, 0);
 211                                 if (endptr3 == endptr2 + 1 || *endptr3 != '\0')
 212                                 {
 213                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 214                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 215                                         exit(1);
 216                                 }
 217                                 break;
 218
 219                         default:
 220                                 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 221                                 exit(1);
 222                 }
 223         }
 224
 225         if (optind == argc)
 226         {
 227                 fprintf(stderr, _("%s: no data directory specified\n"), progname);
 228                 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 229                 exit(1);
 230         }
 231
 232         /*
 233          * Don't allow pg_resetxlog to be run as root, to avoid overwriting the
 234          * ownership of files in the data directory. We need only check for root
 235          * -- any other user won't have sufficient permissions to modify files in
 236          * the data directory.
 237          */
 238 #ifndef WIN32
 239         if (geteuid() == 0)
 240         {
 241                 fprintf(stderr, _("%s: cannot be executed by \"root\"\n"),
 242                                 progname);
 243                 fprintf(stderr, _("You must run %s as the PostgreSQL superuser.\n"),
 244                                 progname);
 245                 exit(1);
 246         }
 247 #endif
 248
 249         DataDir = argv[optind];
 250
 251         if (chdir(DataDir) < 0)
 252         {
 253                 fprintf(stderr, _("%s: could not change directory to \"%s\": %s\n"),
 254                                 progname, DataDir, strerror(errno));
 255                 exit(1);
 256         }
 257
 258         /*
 259          * Check for a postmaster lock file --- if there is one, refuse to
 260          * proceed, on grounds we might be interfering with a live installation.
 261          */
 262         snprintf(path, MAXPGPATH, "%s/postmaster.pid", DataDir);
 263
 264         if ((fd = open(path, O_RDONLY, 0)) < 0)
 265         {
 266                 if (errno != ENOENT)
 267                 {
 268                         fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"), progname, path, strerror(errno));
 269                         exit(1);
 270                 }
 271         }
 272         else
 273         {
 274                 fprintf(stderr, _("%s: lock file \"%s\" exists\n"
 275                                                   "Is a server running?  If not, delete the lock file and try again.\n"),
 276                                 progname, path);
 277                 exit(1);
 278         }
 279
 280         /*
 281          * Attempt to read the existing pg_control file
 282          */
 283         if (!ReadControlFile())
 284                 GuessControlValues();
 285
 286         /*
 287          * Adjust fields if required by switches.  (Do this now so that printout,
 288          * if any, includes these values.)
 289          */
 290         if (set_xid_epoch != -1)
 291                 ControlFile.checkPointCopy.nextXidEpoch = set_xid_epoch;
 292
 293         if (set_xid != 0)
 294                 ControlFile.checkPointCopy.nextXid = set_xid;
 295
 296         if (set_oid != 0)
 297                 ControlFile.checkPointCopy.nextOid = set_oid;
 298
 299         if (set_mxid != 0)
 300                 ControlFile.checkPointCopy.nextMulti = set_mxid;
 301
 302         if (set_mxoff != -1)
 303                 ControlFile.checkPointCopy.nextMultiOffset = set_mxoff;
 304
 305         if (minXlogTli > ControlFile.checkPointCopy.ThisTimeLineID)
 306                 ControlFile.checkPointCopy.ThisTimeLineID = minXlogTli;
 307
 308         if (minXlogId > ControlFile.logId ||
 309                 (minXlogId == ControlFile.logId &&
 310                  minXlogSeg > ControlFile.logSeg))
 311         {
 312                 ControlFile.logId = minXlogId;
 313                 ControlFile.logSeg = minXlogSeg;
 314         }
 315
 316         /*
 317          * If we had to guess anything, and -f was not given, just print the
 318          * guessed values and exit.  Also print if -n is given.
 319          */
 320         if ((guessed && !force) || noupdate)
 321         {
 322                 PrintControlValues(guessed);
 323                 if (!noupdate)
 324                 {
 325                         printf(_("\nIf these values seem acceptable, use -f to force reset.\n"));
 326                         exit(1);
 327                 }
 328                 else
 329                         exit(0);
 330         }
 331
 332         /*
 333          * Don't reset from a dirty pg_control without -f, either.
 334          */
 335         if (ControlFile.state != DB_SHUTDOWNED && !force)
 336         {
 337                 printf(_("The database server was not shut down cleanly.\n"
 338                                  "Resetting the transaction log may cause data to be lost.\n"
 339                                  "If you want to proceed anyway, use -f to force reset.\n"));
 340                 exit(1);
 341         }
 342
 343         /*
 344          * Else, do the dirty deed.
 345          */
 346         RewriteControlFile();
 347         KillExistingXLOG();
 348         WriteEmptyXLOG();
 349
 350         printf(_("Transaction log reset\n"));
 351         return 0;
 352 }
 353
 354
 355 /*
 356  * Try to read the existing pg_control file.
 357  *
 358  * This routine is also responsible for updating old pg_control versions
 359  * to the current format.  (Currently we don't do anything of the sort.)
 360  */
 361 static bool
 362 ReadControlFile(void)
 363 {
 364         int                     fd;
 365         int                     len;
 366         char       *buffer;
 367         pg_crc32        crc;
 368
 369         if ((fd = open(XLOG_CONTROL_FILE, O_RDONLY, 0)) < 0)
 370         {
 371                 /*
 372                  * If pg_control is not there at all, or we can't read it, the odds
 373                  * are we've been handed a bad DataDir path, so give up. User can do
 374                  * "touch pg_control" to force us to proceed.
 375                  */
 376                 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
 377                                 progname, XLOG_CONTROL_FILE, strerror(errno));
 378                 if (errno == ENOENT)
 379                         fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
 380                                                           "  touch %s\n"
 381                                                           "and try again.\n"),
 382                                         XLOG_CONTROL_FILE);
 383                 exit(1);
 384         }
 385
 386         /* Use malloc to ensure we have a maxaligned buffer */
 387         buffer = (char *) malloc(PG_CONTROL_SIZE);
 388
 389         len = read(fd, buffer, PG_CONTROL_SIZE);
 390         if (len < 0)
 391         {
 392                 fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
 393                                 progname, XLOG_CONTROL_FILE, strerror(errno));
 394                 exit(1);
 395         }
 396         close(fd);
 397
 398         if (len >= sizeof(ControlFileData) &&
 399           ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
 400         {
 401                 /* Check the CRC. */
 402                 INIT_CRC32(crc);
 403                 COMP_CRC32(crc,
 404                                    buffer,
 405                                    offsetof(ControlFileData, crc));
 406                 FIN_CRC32(crc);
 407
 408                 if (EQ_CRC32(crc, ((ControlFileData *) buffer)->crc))
 409                 {
 410                         /* Valid data... */
 411                         memcpy(&ControlFile, buffer, sizeof(ControlFile));
 412                         return true;
 413                 }
 414
 415                 fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
 416                                 progname);
 417                 /* We will use the data anyway, but treat it as guessed. */
 418                 memcpy(&ControlFile, buffer, sizeof(ControlFile));
 419                 guessed = true;
 420                 return true;
 421         }
 422
 423         /* Looks like it's a mess. */
 424         fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
 425                         progname);
 426         return false;
 427 }
 428
 429
 430 /*
 431  * Guess at pg_control values when we can't read the old ones.
 432  */
 433 static void
 434 GuessControlValues(void)
 435 {
 436         uint64          sysidentifier;
 437         struct timeval tv;
 438         char       *localeptr;
 439
 440         /*
 441          * Set up a completely default set of pg_control values.
 442          */
 443         guessed = true;
 444         memset(&ControlFile, 0, sizeof(ControlFile));
 445
 446         ControlFile.pg_control_version = PG_CONTROL_VERSION;
 447         ControlFile.catalog_version_no = CATALOG_VERSION_NO;
 448
 449         /*
 450          * Create a new unique installation identifier, since we can no longer use
 451          * any old XLOG records.  See notes in xlog.c about the algorithm.
 452          */
 453         gettimeofday(&tv, NULL);
 454         sysidentifier = ((uint64) tv.tv_sec) << 32;
 455         sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec);
 456
 457         ControlFile.system_identifier = sysidentifier;
 458
 459         ControlFile.checkPointCopy.redo.xlogid = 0;
 460         ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogLongPHD;
 461         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
 462         ControlFile.checkPointCopy.ThisTimeLineID = 1;
 463         ControlFile.checkPointCopy.nextXidEpoch = 0;
 464         ControlFile.checkPointCopy.nextXid = (TransactionId) 514;       /* XXX */
 465         ControlFile.checkPointCopy.nextOid = FirstBootstrapObjectId;
 466         ControlFile.checkPointCopy.nextMulti = FirstMultiXactId;
 467         ControlFile.checkPointCopy.nextMultiOffset = 0;
 468         ControlFile.checkPointCopy.time = time(NULL);
 469
 470         ControlFile.state = DB_SHUTDOWNED;
 471         ControlFile.time = time(NULL);
 472         ControlFile.logId = 0;
 473         ControlFile.logSeg = 1;
 474         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
 475
 476         ControlFile.maxAlign = MAXIMUM_ALIGNOF;
 477         ControlFile.floatFormat = FLOATFORMAT_VALUE;
 478         ControlFile.blcksz = BLCKSZ;
 479         ControlFile.relseg_size = RELSEG_SIZE;
 480         ControlFile.xlog_blcksz = XLOG_BLCKSZ;
 481         ControlFile.xlog_seg_size = XLOG_SEG_SIZE;
 482         ControlFile.nameDataLen = NAMEDATALEN;
 483         ControlFile.indexMaxKeys = INDEX_MAX_KEYS;
 484 #ifdef HAVE_INT64_TIMESTAMP
 485         ControlFile.enableIntTimes = TRUE;
 486 #else
 487         ControlFile.enableIntTimes = FALSE;
 488 #endif
 489         ControlFile.localeBuflen = LOCALE_NAME_BUFLEN;
 490
 491         localeptr = setlocale(LC_COLLATE, "");
 492         if (!localeptr)
 493         {
 494                 fprintf(stderr, _("%s: invalid LC_COLLATE setting\n"), progname);
 495                 exit(1);
 496         }
 497         StrNCpy(ControlFile.lc_collate, localeptr, LOCALE_NAME_BUFLEN);
 498         localeptr = setlocale(LC_CTYPE, "");
 499         if (!localeptr)
 500         {
 501                 fprintf(stderr, _("%s: invalid LC_CTYPE setting\n"), progname);
 502                 exit(1);
 503         }
 504         StrNCpy(ControlFile.lc_ctype, localeptr, LOCALE_NAME_BUFLEN);
 505
 506         /*
 507          * XXX eventually, should try to grovel through old XLOG to develop more
 508          * accurate values for TimeLineID, nextXID, etc.
 509          */
 510 }
 511
 512
 513 /*
 514  * Print the guessed pg_control values when we had to guess.
 515  *
 516  * NB: this display should be just those fields that will not be
 517  * reset by RewriteControlFile().
 518  */
 519 static void
 520 PrintControlValues(bool guessed)
 521 {
 522         char            sysident_str[32];
 523
 524         if (guessed)
 525                 printf(_("Guessed pg_control values:\n\n"));
 526         else
 527                 printf(_("pg_control values:\n\n"));
 528
 529         /*
 530          * Format system_identifier separately to keep platform-dependent format
 531          * code out of the translatable message string.
 532          */
 533         snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
 534                          ControlFile.system_identifier);
 535
 536         printf(_("pg_control version number:            %u\n"),
 537                    ControlFile.pg_control_version);
 538         printf(_("Catalog version number:               %u\n"),
 539                    ControlFile.catalog_version_no);
 540         printf(_("Database system identifier:           %s\n"),
 541                    sysident_str);
 542         printf(_("Current log file ID:                  %u\n"),
 543                    ControlFile.logId);
 544         printf(_("Next log file segment:                %u\n"),
 545                    ControlFile.logSeg);
 546         printf(_("Latest checkpoint's TimeLineID:       %u\n"),
 547                    ControlFile.checkPointCopy.ThisTimeLineID);
 548         printf(_("Latest checkpoint's NextXID:          %u/%u\n"),
 549                    ControlFile.checkPointCopy.nextXidEpoch,
 550                    ControlFile.checkPointCopy.nextXid);
 551         printf(_("Latest checkpoint's NextOID:          %u\n"),
 552                    ControlFile.checkPointCopy.nextOid);
 553         printf(_("Latest checkpoint's NextMultiXactId:  %u\n"),
 554                    ControlFile.checkPointCopy.nextMulti);
 555         printf(_("Latest checkpoint's NextMultiOffset:  %u\n"),
 556                    ControlFile.checkPointCopy.nextMultiOffset);
 557         printf(_("Maximum data alignment:               %u\n"),
 558                    ControlFile.maxAlign);
 559         /* we don't print floatFormat since can't say much useful about it */
 560         printf(_("Database block size:                  %u\n"),
 561                    ControlFile.blcksz);
 562         printf(_("Blocks per segment of large relation: %u\n"),
 563                    ControlFile.relseg_size);
 564         printf(_("WAL block size:                       %u\n"),
 565                    ControlFile.xlog_blcksz);
 566         printf(_("Bytes per WAL segment:                %u\n"),
 567                    ControlFile.xlog_seg_size);
 568         printf(_("Maximum length of identifiers:        %u\n"),
 569                    ControlFile.nameDataLen);
 570         printf(_("Maximum columns in an index:          %u\n"),
 571                    ControlFile.indexMaxKeys);
 572         printf(_("Date/time type storage:               %s\n"),
 573                    (ControlFile.enableIntTimes ? _("64-bit integers") : _("floating-point numbers")));
 574         printf(_("Maximum length of locale name:        %u\n"),
 575                    ControlFile.localeBuflen);
 576         printf(_("LC_COLLATE:                           %s\n"),
 577                    ControlFile.lc_collate);
 578         printf(_("LC_CTYPE:                             %s\n"),
 579                    ControlFile.lc_ctype);
 580 }
 581
 582
 583 /*
 584  * Write out the new pg_control file.
 585  */
 586 static void
 587 RewriteControlFile(void)
 588 {
 589         int                     fd;
 590         char            buffer[PG_CONTROL_SIZE];                /* need not be aligned */
 591
 592         /*
 593          * Adjust fields as needed to force an empty XLOG starting at the next
 594          * available segment.
 595          */
 596         newXlogId = ControlFile.logId;
 597         newXlogSeg = ControlFile.logSeg;
 598
 599         /* adjust in case we are changing segment size */
 600         newXlogSeg *= ControlFile.xlog_seg_size;
 601         newXlogSeg = (newXlogSeg + XLogSegSize - 1) / XLogSegSize;
 602
 603         /* be sure we wrap around correctly at end of a logfile */
 604         NextLogSeg(newXlogId, newXlogSeg);
 605
 606         /* Now we can force the recorded xlog seg size to the right thing. */
 607         ControlFile.xlog_seg_size = XLogSegSize;
 608
 609         ControlFile.checkPointCopy.redo.xlogid = newXlogId;
 610         ControlFile.checkPointCopy.redo.xrecoff =
 611                 newXlogSeg * XLogSegSize + SizeOfXLogLongPHD;
 612         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
 613         ControlFile.checkPointCopy.time = time(NULL);
 614
 615         ControlFile.state = DB_SHUTDOWNED;
 616         ControlFile.time = time(NULL);
 617         ControlFile.logId = newXlogId;
 618         ControlFile.logSeg = newXlogSeg + 1;
 619         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
 620         ControlFile.prevCheckPoint.xlogid = 0;
 621         ControlFile.prevCheckPoint.xrecoff = 0;
 622         ControlFile.minRecoveryPoint.xlogid = 0;
 623         ControlFile.minRecoveryPoint.xrecoff = 0;
 624
 625         /* Contents are protected with a CRC */
 626         INIT_CRC32(ControlFile.crc);
 627         COMP_CRC32(ControlFile.crc,
 628                            (char *) &ControlFile,
 629                            offsetof(ControlFileData, crc));
 630         FIN_CRC32(ControlFile.crc);
 631
 632         /*
 633          * We write out PG_CONTROL_SIZE bytes into pg_control, zero-padding the
 634          * excess over sizeof(ControlFileData).  This reduces the odds of
 635          * premature-EOF errors when reading pg_control.  We'll still fail when we
 636          * check the contents of the file, but hopefully with a more specific
 637          * error than "couldn't read pg_control".
 638          */
 639         if (sizeof(ControlFileData) > PG_CONTROL_SIZE)
 640         {
 641                 fprintf(stderr,
 642                                 _("%s: internal error -- sizeof(ControlFileData) is too large ... fix PG_CONTROL_SIZE\n"),
 643                                 progname);
 644                 exit(1);
 645         }
 646
 647         memset(buffer, 0, PG_CONTROL_SIZE);
 648         memcpy(buffer, &ControlFile, sizeof(ControlFileData));
 649
 650         unlink(XLOG_CONTROL_FILE);
 651
 652         fd = open(XLOG_CONTROL_FILE,
 653                           O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 654                           S_IRUSR | S_IWUSR);
 655         if (fd < 0)
 656         {
 657                 fprintf(stderr, _("%s: could not create pg_control file: %s\n"),
 658                                 progname, strerror(errno));
 659                 exit(1);
 660         }
 661
 662         errno = 0;
 663         if (write(fd, buffer, PG_CONTROL_SIZE) != PG_CONTROL_SIZE)
 664         {
 665                 /* if write didn't set errno, assume problem is no disk space */
 666                 if (errno == 0)
 667                         errno = ENOSPC;
 668                 fprintf(stderr, _("%s: could not write pg_control file: %s\n"),
 669                                 progname, strerror(errno));
 670                 exit(1);
 671         }
 672
 673         if (fsync(fd) != 0)
 674         {
 675                 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
 676                 exit(1);
 677         }
 678
 679         close(fd);
 680 }
 681
 682
 683 /*
 684  * Remove existing XLOG files
 685  */
 686 static void
 687 KillExistingXLOG(void)
 688 {
 689         DIR                *xldir;
 690         struct dirent *xlde;
 691         char            path[MAXPGPATH];
 692
 693         xldir = opendir(XLOGDIR);
 694         if (xldir == NULL)
 695         {
 696                 fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
 697                                 progname, XLOGDIR, strerror(errno));
 698                 exit(1);
 699         }
 700
 701         errno = 0;
 702         while ((xlde = readdir(xldir)) != NULL)
 703         {
 704                 if (strlen(xlde->d_name) == 24 &&
 705                         strspn(xlde->d_name, "0123456789ABCDEF") == 24)
 706                 {
 707                         snprintf(path, MAXPGPATH, "%s/%s", XLOGDIR, xlde->d_name);
 708                         if (unlink(path) < 0)
 709                         {
 710                                 fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
 711                                                 progname, path, strerror(errno));
 712                                 exit(1);
 713                         }
 714                 }
 715                 errno = 0;
 716         }
 717 #ifdef WIN32
 718
 719         /*
 720          * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
 721          * released version
 722          */
 723         if (GetLastError() == ERROR_NO_MORE_FILES)
 724                 errno = 0;
 725 #endif
 726
 727         if (errno)
 728         {
 729                 fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
 730                                 progname, XLOGDIR, strerror(errno));
 731                 exit(1);
 732         }
 733         closedir(xldir);
 734 }
 735
 736
 737 /*
 738  * Write an empty XLOG file, containing only the checkpoint record
 739  * already set up in ControlFile.
 740  */
 741 static void
 742 WriteEmptyXLOG(void)
 743 {
 744         char       *buffer;
 745         XLogPageHeader page;
 746         XLogLongPageHeader longpage;
 747         XLogRecord *record;
 748         pg_crc32        crc;
 749         char            path[MAXPGPATH];
 750         int                     fd;
 751         int                     nbytes;
 752
 753         /* Use malloc() to ensure buffer is MAXALIGNED */
 754         buffer = (char *) malloc(XLOG_BLCKSZ);
 755         page = (XLogPageHeader) buffer;
 756         memset(buffer, 0, XLOG_BLCKSZ);
 757
 758         /* Set up the XLOG page header */
 759         page->xlp_magic = XLOG_PAGE_MAGIC;
 760         page->xlp_info = XLP_LONG_HEADER;
 761         page->xlp_tli = ControlFile.checkPointCopy.ThisTimeLineID;
 762         page->xlp_pageaddr.xlogid =
 763                 ControlFile.checkPointCopy.redo.xlogid;
 764         page->xlp_pageaddr.xrecoff =
 765                 ControlFile.checkPointCopy.redo.xrecoff - SizeOfXLogLongPHD;
 766         longpage = (XLogLongPageHeader) page;
 767         longpage->xlp_sysid = ControlFile.system_identifier;
 768         longpage->xlp_seg_size = XLogSegSize;
 769         longpage->xlp_xlog_blcksz = XLOG_BLCKSZ;
 770
 771         /* Insert the initial checkpoint record */
 772         record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD);
 773         record->xl_prev.xlogid = 0;
 774         record->xl_prev.xrecoff = 0;
 775         record->xl_xid = InvalidTransactionId;
 776         record->xl_tot_len = SizeOfXLogRecord + sizeof(CheckPoint);
 777         record->xl_len = sizeof(CheckPoint);
 778         record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
 779         record->xl_rmid = RM_XLOG_ID;
 780         memcpy(XLogRecGetData(record), &ControlFile.checkPointCopy,
 781                    sizeof(CheckPoint));
 782
 783         INIT_CRC32(crc);
 784         COMP_CRC32(crc, &ControlFile.checkPointCopy, sizeof(CheckPoint));
 785         COMP_CRC32(crc, (char *) record + sizeof(pg_crc32),
 786                            SizeOfXLogRecord - sizeof(pg_crc32));
 787         FIN_CRC32(crc);
 788         record->xl_crc = crc;
 789
 790         /* Write the first page */
 791         XLogFilePath(path, ControlFile.checkPointCopy.ThisTimeLineID,
 792                                  newXlogId, newXlogSeg);
 793
 794         unlink(path);
 795
 796         fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 797                           S_IRUSR | S_IWUSR);
 798         if (fd < 0)
 799         {
 800                 fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
 801                                 progname, path, strerror(errno));
 802                 exit(1);
 803         }
 804
 805         errno = 0;
 806         if (write(fd, buffer, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 807         {
 808                 /* if write didn't set errno, assume problem is no disk space */
 809                 if (errno == 0)
 810                         errno = ENOSPC;
 811                 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
 812                                 progname, path, strerror(errno));
 813                 exit(1);
 814         }
 815
 816         /* Fill the rest of the file with zeroes */
 817         memset(buffer, 0, XLOG_BLCKSZ);
 818         for (nbytes = XLOG_BLCKSZ; nbytes < XLogSegSize; nbytes += XLOG_BLCKSZ)
 819         {
 820                 errno = 0;
 821                 if (write(fd, buffer, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 822                 {
 823                         if (errno == 0)
 824                                 errno = ENOSPC;
 825                         fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
 826                                         progname, path, strerror(errno));
 827                         exit(1);
 828                 }
 829         }
 830
 831         if (fsync(fd) != 0)
 832         {
 833                 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
 834                 exit(1);
 835         }
 836
 837         close(fd);
 838 }
 839
 840
 841 static void
 842 usage(void)
 843 {
 844         printf(_("%s resets the PostgreSQL transaction log.\n\n"), progname);
 845         printf(_("Usage:\n  %s [OPTION]... DATADIR\n\n"), progname);
 846         printf(_("Options:\n"));
 847         printf(_("  -f              force update to be done\n"));
 848         printf(_("  -l TLI,FILE,SEG force minimum WAL starting location for new transaction log\n"));
 849         printf(_("  -m XID          set next multitransaction ID\n"));
 850         printf(_("  -n              no update, just show extracted control values (for testing)\n"));
 851         printf(_("  -o OID          set next OID\n"));
 852         printf(_("  -O OFFSET       set next multitransaction offset\n"));
 853         printf(_("  -x XID          set next transaction ID\n"));
 854         printf(_("  -e XIDEPOCH     set next transaction ID epoch\n"));
 855         printf(_("  --help          show this help, then exit\n"));
 856         printf(_("  --version       output version information, then exit\n"));
 857         printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));
 858 }