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 1.17 2004/03/22 16:46:28 tgl 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 extern int      optind;
  46 extern char *optarg;
  47
  48 #define _(x) gettext((x))
  49
  50
  51 /******************** stuff copied from xlog.c ********************/
  52
  53 /* Increment an xlogid/segment pair */
  54 #define NextLogSeg(logId, logSeg)       \
  55         do { \
  56                 if ((logSeg) >= XLogSegsPerFile-1) \
  57                 { \
  58                         (logId)++; \
  59                         (logSeg) = 0; \
  60                 } \
  61                 else \
  62                         (logSeg)++; \
  63         } while (0)
  64
  65 #define XLogFileName(path, log, seg)    \
  66                         snprintf(path, MAXPGPATH, "%s/%08X%08X",        \
  67                                          XLogDir, log, seg)
  68
  69 /******************** end of stuff copied from xlog.c ********************/
  70
  71 static char XLogDir[MAXPGPATH];
  72 static char ControlFilePath[MAXPGPATH];
  73
  74 static ControlFileData ControlFile;             /* pg_control values */
  75 static uint32 newXlogId,
  76                         newXlogSeg;                     /* ID/Segment of new XLOG segment */
  77 static bool guessed = false;    /* T if we had to guess at any values */
  78 static char *progname;
  79
  80 static bool ReadControlFile(void);
  81 static void GuessControlValues(void);
  82 static void PrintControlValues(bool guessed);
  83 static void RewriteControlFile(void);
  84 static void KillExistingXLOG(void);
  85 static void WriteEmptyXLOG(void);
  86 static void usage(void);
  87
  88
  89 int
  90 main(int argc, char *argv[])
  91 {
  92         int                     c;
  93         bool            force = false;
  94         bool            noupdate = false;
  95         TransactionId set_xid = 0;
  96         Oid                     set_oid = 0;
  97         uint32          minXlogId = 0,
  98                                 minXlogSeg = 0;
  99         char       *endptr;
 100         char       *endptr2;
 101         char       *DataDir;
 102         int                     fd;
 103         char            path[MAXPGPATH];
 104
 105         setlocale(LC_ALL, "");
 106 #ifdef ENABLE_NLS
 107         bindtextdomain("pg_resetxlog", LOCALEDIR);
 108         textdomain("pg_resetxlog");
 109 #endif
 110
 111         progname = get_progname(argv[0]);
 112
 113         if (argc > 1)
 114         {
 115                 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
 116                 {
 117                         usage();
 118                         exit(0);
 119                 }
 120                 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
 121                 {
 122                         puts("pg_resetxlog (PostgreSQL) " PG_VERSION);
 123                         exit(0);
 124                 }
 125         }
 126
 127
 128         while ((c = getopt(argc, argv, "fl:no:x:")) != -1)
 129         {
 130                 switch (c)
 131                 {
 132                         case 'f':
 133                                 force = true;
 134                                 break;
 135
 136                         case 'n':
 137                                 noupdate = true;
 138                                 break;
 139
 140                         case 'x':
 141                                 set_xid = strtoul(optarg, &endptr, 0);
 142                                 if (endptr == optarg || *endptr != '\0')
 143                                 {
 144                                         fprintf(stderr, _("%s: invalid argument for option -x\n"), progname);
 145                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 146                                         exit(1);
 147                                 }
 148                                 if (set_xid == 0)
 149                                 {
 150                                         fprintf(stderr, _("%s: transaction ID (-x) must not be 0\n"), progname);
 151                                         exit(1);
 152                                 }
 153                                 break;
 154
 155                         case 'o':
 156                                 set_oid = strtoul(optarg, &endptr, 0);
 157                                 if (endptr == optarg || *endptr != '\0')
 158                                 {
 159                                         fprintf(stderr, _("%s: invalid argument for option -o\n"), progname);
 160                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 161                                         exit(1);
 162                                 }
 163                                 if (set_oid == 0)
 164                                 {
 165                                         fprintf(stderr, _("%s: OID (-o) must not be 0\n"), progname);
 166                                         exit(1);
 167                                 }
 168                                 break;
 169
 170                         case 'l':
 171                                 minXlogId = strtoul(optarg, &endptr, 0);
 172                                 if (endptr == optarg || *endptr != ',')
 173                                 {
 174                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 175                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 176                                         exit(1);
 177                                 }
 178                                 minXlogSeg = strtoul(endptr + 1, &endptr2, 0);
 179                                 if (endptr2 == endptr + 1 || *endptr2 != '\0')
 180                                 {
 181                                         fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
 182                                         fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 183                                         exit(1);
 184                                 }
 185                                 break;
 186
 187                         default:
 188                                 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 189                                 exit(1);
 190                 }
 191         }
 192
 193         if (optind == argc)
 194         {
 195                 fprintf(stderr, _("%s: no data directory specified\n"), progname);
 196                 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 197                 exit(1);
 198         }
 199
 200         DataDir = argv[optind];
 201         snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
 202         snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
 203
 204         /*
 205          * Check for a postmaster lock file --- if there is one, refuse to
 206          * proceed, on grounds we might be interfering with a live
 207          * installation.
 208          */
 209         snprintf(path, MAXPGPATH, "%s/postmaster.pid", DataDir);
 210
 211         if ((fd = open(path, O_RDONLY)) < 0)
 212         {
 213                 if (errno != ENOENT)
 214                 {
 215                         fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"), progname, path, strerror(errno));
 216                         exit(1);
 217                 }
 218         }
 219         else
 220         {
 221                 fprintf(stderr, _("%s: lock file \"%s\" exists\n"
 222                                                   "Is a server running?  If not, delete the lock file and try again.\n"),
 223                                 progname, path);
 224                 exit(1);
 225         }
 226
 227         /*
 228          * Attempt to read the existing pg_control file
 229          */
 230         if (!ReadControlFile())
 231                 GuessControlValues();
 232
 233         /*
 234          * Adjust fields if required by switches.  (Do this now so that
 235          * printout, if any, includes these values.)
 236          */
 237         if (set_xid != 0)
 238                 ControlFile.checkPointCopy.nextXid = set_xid;
 239
 240         if (set_oid != 0)
 241                 ControlFile.checkPointCopy.nextOid = set_oid;
 242
 243         if (minXlogId > ControlFile.logId ||
 244                 (minXlogId == ControlFile.logId &&
 245                  minXlogSeg > ControlFile.logSeg))
 246         {
 247                 ControlFile.logId = minXlogId;
 248                 ControlFile.logSeg = minXlogSeg;
 249         }
 250
 251         /*
 252          * If we had to guess anything, and -f was not given, just print the
 253          * guessed values and exit.  Also print if -n is given.
 254          */
 255         if ((guessed && !force) || noupdate)
 256         {
 257                 PrintControlValues(guessed);
 258                 if (!noupdate)
 259                 {
 260                         printf(_("\nIf these values seem acceptable, use -f to force reset.\n"));
 261                         exit(1);
 262                 }
 263                 else
 264                         exit(0);
 265         }
 266
 267         /*
 268          * Don't reset from a dirty pg_control without -f, either.
 269          */
 270         if (ControlFile.state != DB_SHUTDOWNED && !force)
 271         {
 272                 printf(_("The database server was not shut down cleanly.\n"
 273                          "Resetting the transaction log may cause data to be lost.\n"
 274                          "If you want to proceed anyway, use -f to force reset.\n"));
 275                 exit(1);
 276         }
 277
 278         /*
 279          * Else, do the dirty deed.
 280          */
 281         RewriteControlFile();
 282         KillExistingXLOG();
 283         WriteEmptyXLOG();
 284
 285         printf(_("Transaction log reset\n"));
 286         return 0;
 287 }
 288
 289
 290 /*
 291  * Try to read the existing pg_control file.
 292  *
 293  * This routine is also responsible for updating old pg_control versions
 294  * to the current format.  (Currently we don't do anything of the sort.)
 295  */
 296 static bool
 297 ReadControlFile(void)
 298 {
 299         int                     fd;
 300         int                     len;
 301         char       *buffer;
 302         crc64           crc;
 303
 304         if ((fd = open(ControlFilePath, O_RDONLY)) < 0)
 305         {
 306                 /*
 307                  * If pg_control is not there at all, or we can't read it, the
 308                  * odds are we've been handed a bad DataDir path, so give up. User
 309                  * can do "touch pg_control" to force us to proceed.
 310                  */
 311                 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
 312                                 progname, ControlFilePath, strerror(errno));
 313                 if (errno == ENOENT)
 314                         fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
 315                                                           "  touch %s\n"
 316                                                           "and try again.\n"),
 317                                         ControlFilePath);
 318                 exit(1);
 319         }
 320
 321         /* Use malloc to ensure we have a maxaligned buffer */
 322         buffer = (char *) malloc(BLCKSZ);
 323
 324         len = read(fd, buffer, BLCKSZ);
 325         if (len < 0)
 326         {
 327                 fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
 328                                 progname, ControlFilePath, strerror(errno));
 329                 exit(1);
 330         }
 331         close(fd);
 332
 333         if (len >= sizeof(ControlFileData) &&
 334                 ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
 335         {
 336                 /* Check the CRC. */
 337                 INIT_CRC64(crc);
 338                 COMP_CRC64(crc,
 339                                    buffer + sizeof(crc64),
 340                                    sizeof(ControlFileData) - sizeof(crc64));
 341                 FIN_CRC64(crc);
 342
 343                 if (EQ_CRC64(crc, ((ControlFileData *) buffer)->crc))
 344                 {
 345                         /* Valid data... */
 346                         memcpy(&ControlFile, buffer, sizeof(ControlFile));
 347                         return true;
 348                 }
 349
 350                 fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
 351                                 progname);
 352                 /* We will use the data anyway, but treat it as guessed. */
 353                 memcpy(&ControlFile, buffer, sizeof(ControlFile));
 354                 guessed = true;
 355                 return true;
 356         }
 357
 358         /* Looks like it's a mess. */
 359         fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
 360                         progname);
 361         return false;
 362 }
 363
 364
 365 /*
 366  * Guess at pg_control values when we can't read the old ones.
 367  */
 368 static void
 369 GuessControlValues(void)
 370 {
 371         uint64          sysidentifier;
 372         struct timeval tv;
 373         char       *localeptr;
 374
 375         /*
 376          * Set up a completely default set of pg_control values.
 377          */
 378         guessed = true;
 379         memset(&ControlFile, 0, sizeof(ControlFile));
 380
 381         ControlFile.pg_control_version = PG_CONTROL_VERSION;
 382         ControlFile.catalog_version_no = CATALOG_VERSION_NO;
 383
 384         /*
 385          * Create a new unique installation identifier, since we can no longer
 386          * use any old XLOG records.  See notes in xlog.c about the algorithm.
 387          */
 388         gettimeofday(&tv, NULL);
 389         sysidentifier = ((uint64) tv.tv_sec) << 32;
 390         sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec);
 391
 392         ControlFile.system_identifier = sysidentifier;
 393
 394         ControlFile.checkPointCopy.redo.xlogid = 0;
 395         ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD;
 396         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
 397         ControlFile.checkPointCopy.ThisStartUpID = 0;
 398         ControlFile.checkPointCopy.nextXid = (TransactionId) 514;       /* XXX */
 399         ControlFile.checkPointCopy.nextOid = BootstrapObjectIdData;
 400         ControlFile.checkPointCopy.time = time(NULL);
 401
 402         ControlFile.state = DB_SHUTDOWNED;
 403         ControlFile.time = time(NULL);
 404         ControlFile.logId = 0;
 405         ControlFile.logSeg = 1;
 406         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
 407
 408         ControlFile.blcksz = BLCKSZ;
 409         ControlFile.relseg_size = RELSEG_SIZE;
 410         ControlFile.xlog_seg_size = XLOG_SEG_SIZE;
 411         ControlFile.nameDataLen = NAMEDATALEN;
 412         ControlFile.funcMaxArgs = FUNC_MAX_ARGS;
 413 #ifdef HAVE_INT64_TIMESTAMP
 414         ControlFile.enableIntTimes = TRUE;
 415 #else
 416         ControlFile.enableIntTimes = FALSE;
 417 #endif
 418         ControlFile.localeBuflen = LOCALE_NAME_BUFLEN;
 419
 420         localeptr = setlocale(LC_COLLATE, "");
 421         if (!localeptr)
 422         {
 423                 fprintf(stderr, _("%s: invalid LC_COLLATE setting\n"), progname);
 424                 exit(1);
 425         }
 426         StrNCpy(ControlFile.lc_collate, localeptr, LOCALE_NAME_BUFLEN);
 427         localeptr = setlocale(LC_CTYPE, "");
 428         if (!localeptr)
 429         {
 430                 fprintf(stderr, _("%s: invalid LC_CTYPE setting\n"), progname);
 431                 exit(1);
 432         }
 433         StrNCpy(ControlFile.lc_ctype, localeptr, LOCALE_NAME_BUFLEN);
 434
 435         /*
 436          * XXX eventually, should try to grovel through old XLOG to develop
 437          * more accurate values for startupid, nextXID, and nextOID.
 438          */
 439 }
 440
 441
 442 /*
 443  * Print the guessed pg_control values when we had to guess.
 444  *
 445  * NB: this display should be just those fields that will not be
 446  * reset by RewriteControlFile().
 447  */
 448 static void
 449 PrintControlValues(bool guessed)
 450 {
 451         char            sysident_str[32];
 452
 453         if (guessed)
 454                 printf(_("Guessed pg_control values:\n\n"));
 455         else
 456                 printf(_("pg_control values:\n\n"));
 457
 458         /*
 459          * Format system_identifier separately to keep platform-dependent format
 460          * code out of the translatable message string.
 461          */
 462         snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
 463                          ControlFile.system_identifier);
 464
 465         printf(_("pg_control version number:            %u\n"), ControlFile.pg_control_version);
 466         printf(_("Catalog version number:               %u\n"), ControlFile.catalog_version_no);
 467         printf(_("Database system identifier:           %s\n"), sysident_str);
 468         printf(_("Current log file ID:                  %u\n"), ControlFile.logId);
 469         printf(_("Next log file segment:                %u\n"), ControlFile.logSeg);
 470         printf(_("Latest checkpoint's StartUpID:        %u\n"), ControlFile.checkPointCopy.ThisStartUpID);
 471         printf(_("Latest checkpoint's NextXID:          %u\n"), ControlFile.checkPointCopy.nextXid);
 472         printf(_("Latest checkpoint's NextOID:          %u\n"), ControlFile.checkPointCopy.nextOid);
 473         printf(_("Database block size:                  %u\n"), ControlFile.blcksz);
 474         printf(_("Blocks per segment of large relation: %u\n"), ControlFile.relseg_size);
 475         printf(_("Maximum length of identifiers:        %u\n"), ControlFile.nameDataLen);
 476         printf(_("Maximum number of function arguments: %u\n"), ControlFile.funcMaxArgs);
 477         printf(_("Date/time type storage:               %s\n"),
 478                    (ControlFile.enableIntTimes ? _("64-bit integers") : _("floating-point numbers")));
 479         printf(_("Maximum length of locale name:        %u\n"), ControlFile.localeBuflen);
 480         printf(_("LC_COLLATE:                           %s\n"), ControlFile.lc_collate);
 481         printf(_("LC_CTYPE:                             %s\n"), ControlFile.lc_ctype);
 482 }
 483
 484
 485 /*
 486  * Write out the new pg_control file.
 487  */
 488 static void
 489 RewriteControlFile(void)
 490 {
 491         int                     fd;
 492         char            buffer[BLCKSZ]; /* need not be aligned */
 493
 494         /*
 495          * Adjust fields as needed to force an empty XLOG starting at the next
 496          * available segment.
 497          */
 498         newXlogId = ControlFile.logId;
 499         newXlogSeg = ControlFile.logSeg;
 500
 501         /* adjust in case we are changing segment size */
 502         newXlogSeg *= ControlFile.xlog_seg_size;
 503         newXlogSeg = (newXlogSeg + XLogSegSize-1) / XLogSegSize;
 504
 505         /* be sure we wrap around correctly at end of a logfile */
 506         NextLogSeg(newXlogId, newXlogSeg);
 507
 508         /* Now we can force the recorded xlog seg size to the right thing. */
 509         ControlFile.xlog_seg_size = XLogSegSize;
 510
 511         ControlFile.checkPointCopy.redo.xlogid = newXlogId;
 512         ControlFile.checkPointCopy.redo.xrecoff =
 513                 newXlogSeg * XLogSegSize + SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD;
 514         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
 515         ControlFile.checkPointCopy.time = time(NULL);
 516
 517         ControlFile.state = DB_SHUTDOWNED;
 518         ControlFile.time = time(NULL);
 519         ControlFile.logId = newXlogId;
 520         ControlFile.logSeg = newXlogSeg + 1;
 521         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
 522         ControlFile.prevCheckPoint.xlogid = 0;
 523         ControlFile.prevCheckPoint.xrecoff = 0;
 524
 525         /* Contents are protected with a CRC */
 526         INIT_CRC64(ControlFile.crc);
 527         COMP_CRC64(ControlFile.crc,
 528                            (char *) &ControlFile + sizeof(crc64),
 529                            sizeof(ControlFileData) - sizeof(crc64));
 530         FIN_CRC64(ControlFile.crc);
 531
 532         /*
 533          * We write out BLCKSZ bytes into pg_control, zero-padding the excess
 534          * over sizeof(ControlFileData).  This reduces the odds of
 535          * premature-EOF errors when reading pg_control.  We'll still fail
 536          * when we check the contents of the file, but hopefully with a more
 537          * specific error than "couldn't read pg_control".
 538          */
 539         if (sizeof(ControlFileData) > BLCKSZ)
 540         {
 541                 fprintf(stderr,
 542                                 _("%s: internal error -- sizeof(ControlFileData) is too large ... fix xlog.c\n"),
 543                                 progname);
 544                 exit(1);
 545         }
 546
 547         memset(buffer, 0, BLCKSZ);
 548         memcpy(buffer, &ControlFile, sizeof(ControlFileData));
 549
 550         unlink(ControlFilePath);
 551
 552         fd = open(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, S_IRUSR | S_IWUSR);
 553         if (fd < 0)
 554         {
 555                 fprintf(stderr, _("%s: could not create pg_control file: %s\n"),
 556                                 progname, strerror(errno));
 557                 exit(1);
 558         }
 559
 560         errno = 0;
 561         if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 562         {
 563                 /* if write didn't set errno, assume problem is no disk space */
 564                 if (errno == 0)
 565                         errno = ENOSPC;
 566                 fprintf(stderr, _("%s: could not write pg_control file: %s\n"),
 567                                 progname, strerror(errno));
 568                 exit(1);
 569         }
 570
 571         if (fsync(fd) != 0)
 572         {
 573                 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
 574                 exit(1);
 575         }
 576
 577         close(fd);
 578 }
 579
 580
 581 /*
 582  * Remove existing XLOG files
 583  */
 584 static void
 585 KillExistingXLOG(void)
 586 {
 587         DIR                *xldir;
 588         struct dirent *xlde;
 589         char            path[MAXPGPATH];
 590
 591         xldir = opendir(XLogDir);
 592         if (xldir == NULL)
 593         {
 594                 fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
 595                                 progname, XLogDir, strerror(errno));
 596                 exit(1);
 597         }
 598
 599         errno = 0;
 600         while ((xlde = readdir(xldir)) != NULL)
 601         {
 602                 if (strlen(xlde->d_name) == 16 &&
 603                         strspn(xlde->d_name, "0123456789ABCDEF") == 16)
 604                 {
 605                         snprintf(path, MAXPGPATH, "%s/%s", XLogDir, xlde->d_name);
 606                         if (unlink(path) < 0)
 607                         {
 608                                 fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
 609                                                 progname, path, strerror(errno));
 610                                 exit(1);
 611                         }
 612                 }
 613                 errno = 0;
 614         }
 615 #ifdef WIN32
 616         /* This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but
 617            not in released version */
 618         if (GetLastError() == ERROR_NO_MORE_FILES)
 619                 errno = 0;
 620 #endif
 621
 622         if (errno)
 623         {
 624                 fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
 625                                 progname, XLogDir, strerror(errno));
 626                 exit(1);
 627         }
 628         closedir(xldir);
 629 }
 630
 631
 632 /*
 633  * Write an empty XLOG file, containing only the checkpoint record
 634  * already set up in ControlFile.
 635  */
 636 static void
 637 WriteEmptyXLOG(void)
 638 {
 639         char       *buffer;
 640         XLogPageHeader page;
 641         XLogRecord *record;
 642         XLogFileHeaderData *fhdr;
 643         crc64           crc;
 644         char            path[MAXPGPATH];
 645         int                     fd;
 646         int                     nbytes;
 647
 648         /* Use malloc() to ensure buffer is MAXALIGNED */
 649         buffer = (char *) malloc(BLCKSZ);
 650         page = (XLogPageHeader) buffer;
 651         memset(buffer, 0, BLCKSZ);
 652
 653         /* Set up the XLOG page header */
 654         page->xlp_magic = XLOG_PAGE_MAGIC;
 655         page->xlp_info = 0;
 656         page->xlp_sui = ControlFile.checkPointCopy.ThisStartUpID;
 657         page->xlp_pageaddr.xlogid =
 658                 ControlFile.checkPointCopy.redo.xlogid;
 659         page->xlp_pageaddr.xrecoff =
 660                 ControlFile.checkPointCopy.redo.xrecoff -
 661                 (SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD);
 662
 663         /* Insert the file header record */
 664         record = (XLogRecord *) ((char *) page + SizeOfXLogPHD);
 665         record->xl_prev.xlogid = 0;
 666         record->xl_prev.xrecoff = 0;
 667         record->xl_xact_prev.xlogid = 0;
 668         record->xl_xact_prev.xrecoff = 0;
 669         record->xl_xid = InvalidTransactionId;
 670         record->xl_len = SizeOfXLogFHD;
 671         record->xl_info = XLOG_FILE_HEADER;
 672         record->xl_rmid = RM_XLOG_ID;
 673         fhdr = (XLogFileHeaderData *) XLogRecGetData(record);
 674         fhdr->xlfhd_sysid = ControlFile.system_identifier;
 675         fhdr->xlfhd_xlogid = page->xlp_pageaddr.xlogid;
 676         fhdr->xlfhd_segno = page->xlp_pageaddr.xrecoff / XLogSegSize;
 677         fhdr->xlfhd_seg_size = XLogSegSize;
 678
 679         INIT_CRC64(crc);
 680         COMP_CRC64(crc, fhdr, SizeOfXLogFHD);
 681         COMP_CRC64(crc, (char *) record + sizeof(crc64),
 682                            SizeOfXLogRecord - sizeof(crc64));
 683         FIN_CRC64(crc);
 684         record->xl_crc = crc;
 685
 686         /* Insert the initial checkpoint record */
 687         record = (XLogRecord *) ((char *) page + SizeOfXLogPHD + SizeOfXLogRecord + SizeOfXLogFHD);
 688         record->xl_prev.xlogid = page->xlp_pageaddr.xlogid;
 689         record->xl_prev.xrecoff = page->xlp_pageaddr.xrecoff + SizeOfXLogPHD;
 690         record->xl_xact_prev.xlogid = 0;
 691         record->xl_xact_prev.xrecoff = 0;
 692         record->xl_xid = InvalidTransactionId;
 693         record->xl_len = sizeof(CheckPoint);
 694         record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
 695         record->xl_rmid = RM_XLOG_ID;
 696         memcpy(XLogRecGetData(record), &ControlFile.checkPointCopy,
 697                    sizeof(CheckPoint));
 698
 699         INIT_CRC64(crc);
 700         COMP_CRC64(crc, &ControlFile.checkPointCopy, sizeof(CheckPoint));
 701         COMP_CRC64(crc, (char *) record + sizeof(crc64),
 702                            SizeOfXLogRecord - sizeof(crc64));
 703         FIN_CRC64(crc);
 704         record->xl_crc = crc;
 705
 706         /* Write the first page */
 707         XLogFileName(path, newXlogId, newXlogSeg);
 708
 709         unlink(path);
 710
 711         fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 712                           S_IRUSR | S_IWUSR);
 713         if (fd < 0)
 714         {
 715                 fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
 716                                 progname, path, strerror(errno));
 717                 exit(1);
 718         }
 719
 720         errno = 0;
 721         if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 722         {
 723                 /* if write didn't set errno, assume problem is no disk space */
 724                 if (errno == 0)
 725                         errno = ENOSPC;
 726                 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
 727                                 progname, path, strerror(errno));
 728                 exit(1);
 729         }
 730
 731         /* Fill the rest of the file with zeroes */
 732         memset(buffer, 0, BLCKSZ);
 733         for (nbytes = BLCKSZ; nbytes < XLogSegSize; nbytes += BLCKSZ)
 734         {
 735                 errno = 0;
 736                 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 737                 {
 738                         if (errno == 0)
 739                                 errno = ENOSPC;
 740                         fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
 741                                         progname, path, strerror(errno));
 742                         exit(1);
 743                 }
 744         }
 745
 746         if (fsync(fd) != 0)
 747         {
 748                 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
 749                 exit(1);
 750         }
 751
 752         close(fd);
 753 }
 754
 755
 756 static void
 757 usage(void)
 758 {
 759         printf(_("%s resets the PostgreSQL transaction log.\n\n"), progname);
 760         printf(_("Usage:\n  %s [OPTION]... DATADIR\n\n"), progname);
 761         printf(_("Options:\n"));
 762         printf(_("  -f              force update to be done\n"));
 763         printf(_("  -l FILEID,SEG   force minimum WAL starting location for new transaction log\n"));
 764         printf(_("  -n              no update, just show extracted control values (for testing)\n"));
 765         printf(_("  -o OID          set next OID\n"));
 766         printf(_("  -x XID          set next transaction ID\n"));
 767         printf(_("  --help          show this help, then exit\n"));
 768         printf(_("  --version       output version information, then exit\n"));
 769         printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));
 770 }