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) 1996-2003, 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 1.16 2004/02/17 03:45:17 momjian Exp $
  27  *
  28  *-------------------------------------------------------------------------
  29  */
  30 #include "postgres.h"
  31
  32 #include <errno.h>
  33 #include <unistd.h>
  34 #include <time.h>
  35 #include <sys/stat.h>
  36 #include <sys/time.h>
  37 #include <fcntl.h>
  38 #include <dirent.h>
  39 #include <locale.h>
  40
  41 #include "access/xlog.h"
  42 #include "catalog/catversion.h"
  43 #include "catalog/pg_control.h"
  44
  45 /******************** stuff copied from xlog.c ********************/
  46
  47 /* Increment an xlogid/segment pair */
  48 #define NextLogSeg(logId, logSeg)       \
  49         do { \
  50                 if ((logSeg) >= XLogSegsPerFile-1) \
  51                 { \
  52                         (logId)++; \
  53                         (logSeg) = 0; \
  54                 } \
  55                 else \
  56                         (logSeg)++; \
  57         } while (0)
  58
  59 #define XLogFileName(path, log, seg)    \
  60                         snprintf(path, MAXPGPATH, "%s/%08X%08X",        \
  61                                          XLogDir, log, seg)
  62
  63 /******************** end of stuff copied from xlog.c ********************/
  64
  65 #define _(x) gettext((x))
  66
  67 static char XLogDir[MAXPGPATH];
  68 static char ControlFilePath[MAXPGPATH];
  69
  70 static ControlFileData ControlFile;             /* pg_control values */
  71 static uint32 newXlogId,
  72                         newXlogSeg;                     /* ID/Segment of new XLOG segment */
  73 static bool guessed = false;    /* T if we had to guess at any values */
  74 static char *progname;
  75
  76 static bool ReadControlFile(void);
  77 static void GuessControlValues(void);
  78 static void PrintControlValues(bool guessed);
  79 static void RewriteControlFile(void);
  80 static void KillExistingXLOG(void);
  81 static void WriteEmptyXLOG(void);
  82 static void usage(void);
  83
  84 extern char *optarg;
  85
  86
  87
  88 int
  89 main(int argc, char *argv[])
  90 {
  91         int                     c;
  92         bool            force = false;
  93         bool            noupdate = false;
  94         TransactionId set_xid = 0;
  95         Oid                     set_oid = 0;
  96         uint32          minXlogId = 0,
  97                                 minXlogSeg = 0;
  98         char       *endptr;
  99         char       *endptr2;
 100         char       *DataDir;
 101         int                     fd;
 102         char            path[MAXPGPATH];
 103
 104         setlocale(LC_ALL, "");
 105 #ifdef ENABLE_NLS
 106         bindtextdomain("pg_resetxlog", LOCALEDIR);
 107         textdomain("pg_resetxlog");
 108 #endif
 109
 110         progname = get_progname(argv[0]);
 111
 112         if (argc > 1)
 113         {
 114                 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
 115                 {
 116                         usage();
 117                         exit(0);
 118                 }
 119                 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
 120                 {
 121                         puts("pg_resetxlog (PostgreSQL) " PG_VERSION);
 122                         exit(0);
 123                 }
 124         }
 125
 126
 127         while ((c = getopt(argc, argv, "fl:no:x:")) != -1)
 128         {
 129                 switch (c)
 130                 {
 131                         case 'f':
 132                                 force = true;
 133                                 break;
 134
 135                         case 'n':
 136                                 noupdate = true;
 137                                 break;
 138
 139                         case 'x':
 140                                 set_xid = strtoul(optarg, &endptr, 0);
 141                                 if (endptr == optarg || *endptr != '\0')
 142                                 {
 143                                         fprintf(stderr, _("%s: invalid argument for option -x\n"), progname);
 144                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 145                                         exit(1);
 146                                 }
 147                                 if (set_xid == 0)
 148                                 {
 149                                         fprintf(stderr, _("%s: transaction ID (-x) must not be 0\n"), progname);
 150                                         exit(1);
 151                                 }
 152                                 break;
 153
 154                         case 'o':
 155                                 set_oid = strtoul(optarg, &endptr, 0);
 156                                 if (endptr == optarg || *endptr != '\0')
 157                                 {
 158                                         fprintf(stderr, _("%s: invalid argument for option -o\n"), progname);
 159                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 160                                         exit(1);
 161                                 }
 162                                 if (set_oid == 0)
 163                                 {
 164                                         fprintf(stderr, _("%s: OID (-o) must not be 0\n"), progname);
 165                                         exit(1);
 166                                 }
 167                                 break;
 168
 169                         case 'l':
 170                                 minXlogId = strtoul(optarg, &endptr, 0);
 171                                 if (endptr == optarg || *endptr != ',')
 172                                 {
 173                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 174                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 175                                         exit(1);
 176                                 }
 177                                 minXlogSeg = strtoul(endptr + 1, &endptr2, 0);
 178                                 if (endptr2 == endptr + 1 || *endptr2 != '\0')
 179                                 {
 180                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 181                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 182                                         exit(1);
 183                                 }
 184                                 break;
 185
 186                         default:
 187                                 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 188                                 exit(1);
 189                 }
 190         }
 191
 192         if (optind == argc)
 193         {
 194                 fprintf(stderr, _("%s: no data directory specified\n"), progname);
 195                 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 196                 exit(1);
 197         }
 198
 199         DataDir = argv[optind];
 200         snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
 201         snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
 202
 203         /*
 204          * Check for a postmaster lock file --- if there is one, refuse to
 205          * proceed, on grounds we might be interfering with a live
 206          * installation.
 207          */
 208         snprintf(path, MAXPGPATH, "%s/postmaster.pid", DataDir);
 209
 210         if ((fd = open(path, O_RDONLY)) < 0)
 211         {
 212                 if (errno != ENOENT)
 213                 {
 214                         fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"), progname, path, strerror(errno));
 215                         exit(1);
 216                 }
 217         }
 218         else
 219         {
 220                 fprintf(stderr, _("%s: lock file \"%s\" exists\n"
 221                                                   "Is a server running?  If not, delete the lock file and try again.\n"),
 222                                 progname, path);
 223                 exit(1);
 224         }
 225
 226         /*
 227          * Attempt to read the existing pg_control file
 228          */
 229         if (!ReadControlFile())
 230                 GuessControlValues();
 231
 232         /*
 233          * Adjust fields if required by switches.  (Do this now so that
 234          * printout, if any, includes these values.)
 235          */
 236         if (set_xid != 0)
 237                 ControlFile.checkPointCopy.nextXid = set_xid;
 238
 239         if (set_oid != 0)
 240                 ControlFile.checkPointCopy.nextOid = set_oid;
 241
 242         if (minXlogId > ControlFile.logId ||
 243                 (minXlogId == ControlFile.logId &&
 244                  minXlogSeg > ControlFile.logSeg))
 245         {
 246                 ControlFile.logId = minXlogId;
 247                 ControlFile.logSeg = minXlogSeg;
 248         }
 249
 250         /*
 251          * If we had to guess anything, and -f was not given, just print the
 252          * guessed values and exit.  Also print if -n is given.
 253          */
 254         if ((guessed && !force) || noupdate)
 255         {
 256                 PrintControlValues(guessed);
 257                 if (!noupdate)
 258                 {
 259                         printf(_("\nIf these values seem acceptable, use -f to force reset.\n"));
 260                         exit(1);
 261                 }
 262                 else
 263                         exit(0);
 264         }
 265
 266         /*
 267          * Don't reset from a dirty pg_control without -f, either.
 268          */
 269         if (ControlFile.state != DB_SHUTDOWNED && !force)
 270         {
 271                 printf(_("The database server was not shut down cleanly.\n"
 272                          "Resetting the transaction log may cause data to be lost.\n"
 273                          "If you want to proceed anyway, use -f to force reset.\n"));
 274                 exit(1);
 275         }
 276
 277         /*
 278          * Else, do the dirty deed.
 279          */
 280         RewriteControlFile();
 281         KillExistingXLOG();
 282         WriteEmptyXLOG();
 283
 284         printf(_("Transaction log reset\n"));
 285         return 0;
 286 }
 287
 288
 289 /*
 290  * Try to read the existing pg_control file.
 291  *
 292  * This routine is also responsible for updating old pg_control versions
 293  * to the current format.  (Currently we don't do anything of the sort.)
 294  */
 295 static bool
 296 ReadControlFile(void)
 297 {
 298         int                     fd;
 299         int                     len;
 300         char       *buffer;
 301         crc64           crc;
 302
 303         if ((fd = open(ControlFilePath, O_RDONLY)) < 0)
 304         {
 305                 /*
 306                  * If pg_control is not there at all, or we can't read it, the
 307                  * odds are we've been handed a bad DataDir path, so give up. User
 308                  * can do "touch pg_control" to force us to proceed.
 309                  */
 310                 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
 311                                 progname, ControlFilePath, strerror(errno));
 312                 if (errno == ENOENT)
 313                         fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
 314                                                           "  touch %s\n"
 315                                                           "and try again.\n"),
 316                                         ControlFilePath);
 317                 exit(1);
 318         }
 319
 320         /* Use malloc to ensure we have a maxaligned buffer */
 321         buffer = (char *) malloc(BLCKSZ);
 322
 323         len = read(fd, buffer, BLCKSZ);
 324         if (len < 0)
 325         {
 326                 fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
 327                                 progname, ControlFilePath, strerror(errno));
 328                 exit(1);
 329         }
 330         close(fd);
 331
 332         if (len >= sizeof(ControlFileData) &&
 333                 ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
 334         {
 335                 /* Check the CRC. */
 336                 INIT_CRC64(crc);
 337                 COMP_CRC64(crc,
 338                                    buffer + sizeof(crc64),
 339                                    sizeof(ControlFileData) - sizeof(crc64));
 340                 FIN_CRC64(crc);
 341
 342                 if (EQ_CRC64(crc, ((ControlFileData *) buffer)->crc))
 343                 {
 344                         /* Valid data... */
 345                         memcpy(&ControlFile, buffer, sizeof(ControlFile));
 346                         return true;
 347                 }
 348
 349                 fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
 350                                 progname);
 351                 /* We will use the data anyway, but treat it as guessed. */
 352                 memcpy(&ControlFile, buffer, sizeof(ControlFile));
 353                 guessed = true;
 354                 return true;
 355         }
 356
 357         /* Looks like it's a mess. */
 358         fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
 359                         progname);
 360         return false;
 361 }
 362
 363
 364 /*
 365  * Guess at pg_control values when we can't read the old ones.
 366  */
 367 static void
 368 GuessControlValues(void)
 369 {
 370         uint64          sysidentifier;
 371         struct timeval tv;
 372         char       *localeptr;
 373
 374         /*
 375          * Set up a completely default set of pg_control values.
 376          */
 377         guessed = true;
 378         memset(&ControlFile, 0, sizeof(ControlFile));
 379
 380         ControlFile.pg_control_version = PG_CONTROL_VERSION;
 381         ControlFile.catalog_version_no = CATALOG_VERSION_NO;
 382
 383         /*
 384          * Create a new unique installation identifier, since we can no longer
 385          * use any old XLOG records.  See notes in xlog.c about the algorithm.
 386          */
 387         gettimeofday(&tv, NULL);
 388         sysidentifier = ((uint64) tv.tv_sec) << 32;
 389         sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec);
 390
 391         ControlFile.system_identifier = sysidentifier;
 392
 393         ControlFile.checkPointCopy.redo.xlogid = 0;
 394         ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD;
 395         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
 396         ControlFile.checkPointCopy.ThisStartUpID = 0;
 397         ControlFile.checkPointCopy.nextXid = (TransactionId) 514;       /* XXX */
 398         ControlFile.checkPointCopy.nextOid = BootstrapObjectIdData;
 399         ControlFile.checkPointCopy.time = time(NULL);
 400
 401         ControlFile.state = DB_SHUTDOWNED;
 402         ControlFile.time = time(NULL);
 403         ControlFile.logId = 0;
 404         ControlFile.logSeg = 1;
 405         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
 406
 407         ControlFile.blcksz = BLCKSZ;
 408         ControlFile.relseg_size = RELSEG_SIZE;
 409         ControlFile.xlog_seg_size = XLOG_SEG_SIZE;
 410         ControlFile.nameDataLen = NAMEDATALEN;
 411         ControlFile.funcMaxArgs = FUNC_MAX_ARGS;
 412 #ifdef HAVE_INT64_TIMESTAMP
 413         ControlFile.enableIntTimes = TRUE;
 414 #else
 415         ControlFile.enableIntTimes = FALSE;
 416 #endif
 417         ControlFile.localeBuflen = LOCALE_NAME_BUFLEN;
 418
 419         localeptr = setlocale(LC_COLLATE, "");
 420         if (!localeptr)
 421         {
 422                 fprintf(stderr, _("%s: invalid LC_COLLATE setting\n"), progname);
 423                 exit(1);
 424         }
 425         StrNCpy(ControlFile.lc_collate, localeptr, LOCALE_NAME_BUFLEN);
 426         localeptr = setlocale(LC_CTYPE, "");
 427         if (!localeptr)
 428         {
 429                 fprintf(stderr, _("%s: invalid LC_CTYPE setting\n"), progname);
 430                 exit(1);
 431         }
 432         StrNCpy(ControlFile.lc_ctype, localeptr, LOCALE_NAME_BUFLEN);
 433
 434         /*
 435          * XXX eventually, should try to grovel through old XLOG to develop
 436          * more accurate values for startupid, nextXID, and nextOID.
 437          */
 438 }
 439
 440
 441 /*
 442  * Print the guessed pg_control values when we had to guess.
 443  *
 444  * NB: this display should be just those fields that will not be
 445  * reset by RewriteControlFile().
 446  */
 447 static void
 448 PrintControlValues(bool guessed)
 449 {
 450         char            sysident_str[32];
 451
 452         if (guessed)
 453                 printf(_("Guessed pg_control values:\n\n"));
 454         else
 455                 printf(_("pg_control values:\n\n"));
 456
 457         /*
 458          * Format system_identifier separately to keep platform-dependent format
 459          * code out of the translatable message string.
 460          */
 461         snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
 462                          ControlFile.system_identifier);
 463
 464         printf(_("pg_control version number:            %u\n"), ControlFile.pg_control_version);
 465         printf(_("Catalog version number:               %u\n"), ControlFile.catalog_version_no);
 466         printf(_("Database system identifier:           %s\n"), sysident_str);
 467         printf(_("Current log file ID:                  %u\n"), ControlFile.logId);
 468         printf(_("Next log file segment:                %u\n"), ControlFile.logSeg);
 469         printf(_("Latest checkpoint's StartUpID:        %u\n"), ControlFile.checkPointCopy.ThisStartUpID);
 470         printf(_("Latest checkpoint's NextXID:          %u\n"), ControlFile.checkPointCopy.nextXid);
 471         printf(_("Latest checkpoint's NextOID:          %u\n"), ControlFile.checkPointCopy.nextOid);
 472         printf(_("Database block size:                  %u\n"), ControlFile.blcksz);
 473         printf(_("Blocks per segment of large relation: %u\n"), ControlFile.relseg_size);
 474         printf(_("Maximum length of identifiers:        %u\n"), ControlFile.nameDataLen);
 475         printf(_("Maximum number of function arguments: %u\n"), ControlFile.funcMaxArgs);
 476         printf(_("Date/time type storage:               %s\n"),
 477                    (ControlFile.enableIntTimes ? _("64-bit integers") : _("floating-point numbers")));
 478         printf(_("Maximum length of locale name:        %u\n"), ControlFile.localeBuflen);
 479         printf(_("LC_COLLATE:                           %s\n"), ControlFile.lc_collate);
 480         printf(_("LC_CTYPE:                             %s\n"), ControlFile.lc_ctype);
 481 }
 482
 483
 484 /*
 485  * Write out the new pg_control file.
 486  */
 487 static void
 488 RewriteControlFile(void)
 489 {
 490         int                     fd;
 491         char            buffer[BLCKSZ]; /* need not be aligned */
 492
 493         /*
 494          * Adjust fields as needed to force an empty XLOG starting at the next
 495          * available segment.
 496          */
 497         newXlogId = ControlFile.logId;
 498         newXlogSeg = ControlFile.logSeg;
 499
 500         /* adjust in case we are changing segment size */
 501         newXlogSeg *= ControlFile.xlog_seg_size;
 502         newXlogSeg = (newXlogSeg + XLogSegSize-1) / XLogSegSize;
 503
 504         /* be sure we wrap around correctly at end of a logfile */
 505         NextLogSeg(newXlogId, newXlogSeg);
 506
 507         /* Now we can force the recorded xlog seg size to the right thing. */
 508         ControlFile.xlog_seg_size = XLogSegSize;
 509
 510         ControlFile.checkPointCopy.redo.xlogid = newXlogId;
 511         ControlFile.checkPointCopy.redo.xrecoff =
 512                 newXlogSeg * XLogSegSize + SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD;
 513         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
 514         ControlFile.checkPointCopy.time = time(NULL);
 515
 516         ControlFile.state = DB_SHUTDOWNED;
 517         ControlFile.time = time(NULL);
 518         ControlFile.logId = newXlogId;
 519         ControlFile.logSeg = newXlogSeg + 1;
 520         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
 521         ControlFile.prevCheckPoint.xlogid = 0;
 522         ControlFile.prevCheckPoint.xrecoff = 0;
 523
 524         /* Contents are protected with a CRC */
 525         INIT_CRC64(ControlFile.crc);
 526         COMP_CRC64(ControlFile.crc,
 527                            (char *) &ControlFile + sizeof(crc64),
 528                            sizeof(ControlFileData) - sizeof(crc64));
 529         FIN_CRC64(ControlFile.crc);
 530
 531         /*
 532          * We write out BLCKSZ bytes into pg_control, zero-padding the excess
 533          * over sizeof(ControlFileData).  This reduces the odds of
 534          * premature-EOF errors when reading pg_control.  We'll still fail
 535          * when we check the contents of the file, but hopefully with a more
 536          * specific error than "couldn't read pg_control".
 537          */
 538         if (sizeof(ControlFileData) > BLCKSZ)
 539         {
 540                 fprintf(stderr,
 541                                 _("%s: internal error -- sizeof(ControlFileData) is too large ... fix xlog.c\n"),
 542                                 progname);
 543                 exit(1);
 544         }
 545
 546         memset(buffer, 0, BLCKSZ);
 547         memcpy(buffer, &ControlFile, sizeof(ControlFileData));
 548
 549         unlink(ControlFilePath);
 550
 551         fd = open(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, S_IRUSR | S_IWUSR);
 552         if (fd < 0)
 553         {
 554                 fprintf(stderr, _("%s: could not create pg_control file: %s\n"),
 555                                 progname, strerror(errno));
 556                 exit(1);
 557         }
 558
 559         errno = 0;
 560         if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 561         {
 562                 /* if write didn't set errno, assume problem is no disk space */
 563                 if (errno == 0)
 564                         errno = ENOSPC;
 565                 fprintf(stderr, _("%s: could not write pg_control file: %s\n"),
 566                                 progname, strerror(errno));
 567                 exit(1);
 568         }
 569
 570         if (fsync(fd) != 0)
 571         {
 572                 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
 573                 exit(1);
 574         }
 575
 576         close(fd);
 577 }
 578
 579
 580 /*
 581  * Remove existing XLOG files
 582  */
 583 static void
 584 KillExistingXLOG(void)
 585 {
 586         DIR                *xldir;
 587         struct dirent *xlde;
 588         char            path[MAXPGPATH];
 589
 590         xldir = opendir(XLogDir);
 591         if (xldir == NULL)
 592         {
 593                 fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
 594                                 progname, XLogDir, strerror(errno));
 595                 exit(1);
 596         }
 597
 598         errno = 0;
 599         while ((xlde = readdir(xldir)) != NULL)
 600         {
 601                 if (strlen(xlde->d_name) == 16 &&
 602                         strspn(xlde->d_name, "0123456789ABCDEF") == 16)
 603                 {
 604                         snprintf(path, MAXPGPATH, "%s/%s", XLogDir, xlde->d_name);
 605                         if (unlink(path) < 0)
 606                         {
 607                                 fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
 608                                                 progname, path, strerror(errno));
 609                                 exit(1);
 610                         }
 611                 }
 612                 errno = 0;
 613         }
 614 #ifdef WIN32
 615         /* This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but
 616            not in released version */
 617         if (GetLastError() == ERROR_NO_MORE_FILES)
 618                 errno = 0;
 619 #endif
 620
 621         if (errno)
 622         {
 623                 fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
 624                                 progname, XLogDir, strerror(errno));
 625                 exit(1);
 626         }
 627         closedir(xldir);
 628 }
 629
 630
 631 /*
 632  * Write an empty XLOG file, containing only the checkpoint record
 633  * already set up in ControlFile.
 634  */
 635 static void
 636 WriteEmptyXLOG(void)
 637 {
 638         char       *buffer;
 639         XLogPageHeader page;
 640         XLogRecord *record;
 641         XLogFileHeaderData *fhdr;
 642         crc64           crc;
 643         char            path[MAXPGPATH];
 644         int                     fd;
 645         int                     nbytes;
 646
 647         /* Use malloc() to ensure buffer is MAXALIGNED */
 648         buffer = (char *) malloc(BLCKSZ);
 649         page = (XLogPageHeader) buffer;
 650         memset(buffer, 0, BLCKSZ);
 651
 652         /* Set up the XLOG page header */
 653         page->xlp_magic = XLOG_PAGE_MAGIC;
 654         page->xlp_info = 0;
 655         page->xlp_sui = ControlFile.checkPointCopy.ThisStartUpID;
 656         page->xlp_pageaddr.xlogid =
 657                 ControlFile.checkPointCopy.redo.xlogid;
 658         page->xlp_pageaddr.xrecoff =
 659                 ControlFile.checkPointCopy.redo.xrecoff -
 660                 (SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD);
 661
 662         /* Insert the file header record */
 663         record = (XLogRecord *) ((char *) page + SizeOfXLogPHD);
 664         record->xl_prev.xlogid = 0;
 665         record->xl_prev.xrecoff = 0;
 666         record->xl_xact_prev.xlogid = 0;
 667         record->xl_xact_prev.xrecoff = 0;
 668         record->xl_xid = InvalidTransactionId;
 669         record->xl_len = SizeOfXLogFHD;
 670         record->xl_info = XLOG_FILE_HEADER;
 671         record->xl_rmid = RM_XLOG_ID;
 672         fhdr = (XLogFileHeaderData *) XLogRecGetData(record);
 673         fhdr->xlfhd_sysid = ControlFile.system_identifier;
 674         fhdr->xlfhd_xlogid = page->xlp_pageaddr.xlogid;
 675         fhdr->xlfhd_segno = page->xlp_pageaddr.xrecoff / XLogSegSize;
 676         fhdr->xlfhd_seg_size = XLogSegSize;
 677
 678         INIT_CRC64(crc);
 679         COMP_CRC64(crc, fhdr, SizeOfXLogFHD);
 680         COMP_CRC64(crc, (char *) record + sizeof(crc64),
 681                            SizeOfXLogRecord - sizeof(crc64));
 682         FIN_CRC64(crc);
 683         record->xl_crc = crc;
 684
 685         /* Insert the initial checkpoint record */
 686         record = (XLogRecord *) ((char *) page + SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD);
 687         record->xl_prev.xlogid = page->xlp_pageaddr.xlogid;
 688         record->xl_prev.xrecoff = page->xlp_pageaddr.xrecoff + SizeOfXLogPHD;
 689         record->xl_xact_prev.xlogid = 0;
 690         record->xl_xact_prev.xrecoff = 0;
 691         record->xl_xid = InvalidTransactionId;
 692         record->xl_len = sizeof(CheckPoint);
 693         record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
 694         record->xl_rmid = RM_XLOG_ID;
 695         memcpy(XLogRecGetData(record), &ControlFile.checkPointCopy,
 696                    sizeof(CheckPoint));
 697
 698         INIT_CRC64(crc);
 699         COMP_CRC64(crc, &ControlFile.checkPointCopy, sizeof(CheckPoint));
 700         COMP_CRC64(crc, (char *) record + sizeof(crc64),
 701                            SizeOfXLogRecord - sizeof(crc64));
 702         FIN_CRC64(crc);
 703         record->xl_crc = crc;
 704
 705         /* Write the first page */
 706         XLogFileName(path, newXlogId, newXlogSeg);
 707
 708         unlink(path);
 709
 710         fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 711                           S_IRUSR | S_IWUSR);
 712         if (fd < 0)
 713         {
 714                 fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
 715                                 progname, path, strerror(errno));
 716                 exit(1);
 717         }
 718
 719         errno = 0;
 720         if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 721         {
 722                 /* if write didn't set errno, assume problem is no disk space */
 723                 if (errno == 0)
 724                         errno = ENOSPC;
 725                 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
 726                                 progname, path, strerror(errno));
 727                 exit(1);
 728         }
 729
 730         /* Fill the rest of the file with zeroes */
 731         memset(buffer, 0, BLCKSZ);
 732         for (nbytes = BLCKSZ; nbytes < XLogSegSize; nbytes += BLCKSZ)
 733         {
 734                 errno = 0;
 735                 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 736                 {
 737                         if (errno == 0)
 738                                 errno = ENOSPC;
 739                         fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
 740                                         progname, path, strerror(errno));
 741                         exit(1);
 742                 }
 743         }
 744
 745         if (fsync(fd) != 0)
 746         {
 747                 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
 748                 exit(1);
 749         }
 750
 751         close(fd);
 752 }
 753
 754
 755 static void
 756 usage(void)
 757 {
 758         printf(_("%s resets the PostgreSQL transaction log.\n\n"), progname);
 759         printf(_("Usage:\n  %s [OPTION]... DATADIR\n\n"), progname);
 760         printf(_("Options:\n"));
 761         printf(_("  -f              force update to be done\n"));
 762         printf(_("  -l FILEID,SEG   force minimum WAL starting location for new transaction log\n"));
 763         printf(_("  -n              no update, just show extracted control values (for testing)\n"));
 764         printf(_("  -o OID          set next OID\n"));
 765         printf(_("  -x XID          set next transaction ID\n"));
 766         printf(_("  --help          show this help, then exit\n"));
 767         printf(_("  --version       output version information, then exit\n"));
 768         printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));
 769 }