LCOV - code coverage report
Current view: top level - src/bin/pg_resetwal - pg_resetwal.c (source / functions) Hit Total Coverage
Test: PostgreSQL 18devel Lines: 482 536 89.9 %
Date: 2025-02-22 07:14:56 Functions: 13 13 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * pg_resetwal.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).
      10             :  *    2. If pg_control is corrupt, attempt to intuit reasonable values,
      11             :  *       by scanning the old xlog if necessary.
      12             :  *    3. Modify pg_control to reflect a "shutdown" state with a checkpoint
      13             :  *       record at the start of xlog.
      14             :  *    4. Flush the existing xlog files and write a new segment with
      15             :  *       just a checkpoint record in it.  The new segment is positioned
      16             :  *       just past the end of the old xlog, so that existing LSNs in
      17             :  *       data pages will appear to be "in the past".
      18             :  * This is all pretty straightforward except for the intuition part of
      19             :  * step 2 ...
      20             :  *
      21             :  *
      22             :  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
      23             :  * Portions Copyright (c) 1994, Regents of the University of California
      24             :  *
      25             :  * src/bin/pg_resetwal/pg_resetwal.c
      26             :  *
      27             :  *-------------------------------------------------------------------------
      28             :  */
      29             : 
      30             : /*
      31             :  * We have to use postgres.h not postgres_fe.h here, because there's so much
      32             :  * backend-only stuff in the XLOG include files we need.  But we need a
      33             :  * frontend-ish environment otherwise.  Hence this ugly hack.
      34             :  */
      35             : #define FRONTEND 1
      36             : 
      37             : #include "postgres.h"
      38             : 
      39             : #include <dirent.h>
      40             : #include <fcntl.h>
      41             : #include <sys/stat.h>
      42             : #include <sys/time.h>
      43             : #include <time.h>
      44             : #include <unistd.h>
      45             : 
      46             : #include "access/heaptoast.h"
      47             : #include "access/multixact.h"
      48             : #include "access/transam.h"
      49             : #include "access/xlog.h"
      50             : #include "access/xlog_internal.h"
      51             : #include "common/controldata_utils.h"
      52             : #include "common/fe_memutils.h"
      53             : #include "common/file_perm.h"
      54             : #include "common/logging.h"
      55             : #include "common/restricted_token.h"
      56             : #include "common/string.h"
      57             : #include "fe_utils/option_utils.h"
      58             : #include "getopt_long.h"
      59             : #include "pg_getopt.h"
      60             : #include "storage/large_object.h"
      61             : 
      62             : static ControlFileData ControlFile; /* pg_control values */
      63             : static XLogSegNo newXlogSegNo;  /* new XLOG segment # */
      64             : static bool guessed = false;    /* T if we had to guess at any values */
      65             : static const char *progname;
      66             : static uint32 set_xid_epoch = (uint32) -1;
      67             : static TransactionId set_oldest_xid = 0;
      68             : static TransactionId set_xid = 0;
      69             : static TransactionId set_oldest_commit_ts_xid = 0;
      70             : static TransactionId set_newest_commit_ts_xid = 0;
      71             : static Oid  set_oid = 0;
      72             : static MultiXactId set_mxid = 0;
      73             : static MultiXactOffset set_mxoff = (MultiXactOffset) -1;
      74             : static TimeLineID minXlogTli = 0;
      75             : static XLogSegNo minXlogSegNo = 0;
      76             : static int  WalSegSz;
      77             : static int  set_wal_segsize;
      78             : static int  set_char_signedness = -1;
      79             : 
      80             : static void CheckDataVersion(void);
      81             : static bool read_controlfile(void);
      82             : static void GuessControlValues(void);
      83             : static void PrintControlValues(bool guessed);
      84             : static void PrintNewControlValues(void);
      85             : static void RewriteControlFile(void);
      86             : static void FindEndOfXLOG(void);
      87             : static void KillExistingXLOG(void);
      88             : static void KillExistingArchiveStatus(void);
      89             : static void KillExistingWALSummaries(void);
      90             : static void WriteEmptyXLOG(void);
      91             : static void usage(void);
      92             : 
      93             : 
      94             : int
      95         244 : main(int argc, char *argv[])
      96             : {
      97             :     static struct option long_options[] = {
      98             :         {"commit-timestamp-ids", required_argument, NULL, 'c'},
      99             :         {"pgdata", required_argument, NULL, 'D'},
     100             :         {"epoch", required_argument, NULL, 'e'},
     101             :         {"force", no_argument, NULL, 'f'},
     102             :         {"next-wal-file", required_argument, NULL, 'l'},
     103             :         {"multixact-ids", required_argument, NULL, 'm'},
     104             :         {"dry-run", no_argument, NULL, 'n'},
     105             :         {"next-oid", required_argument, NULL, 'o'},
     106             :         {"multixact-offset", required_argument, NULL, 'O'},
     107             :         {"oldest-transaction-id", required_argument, NULL, 'u'},
     108             :         {"next-transaction-id", required_argument, NULL, 'x'},
     109             :         {"wal-segsize", required_argument, NULL, 1},
     110             :         {"char-signedness", required_argument, NULL, 2},
     111             :         {NULL, 0, NULL, 0}
     112             :     };
     113             : 
     114             :     int         c;
     115         244 :     bool        force = false;
     116         244 :     bool        noupdate = false;
     117         244 :     MultiXactId set_oldestmxid = 0;
     118             :     char       *endptr;
     119             :     char       *endptr2;
     120         244 :     char       *DataDir = NULL;
     121         244 :     char       *log_fname = NULL;
     122             :     int         fd;
     123             : 
     124         244 :     pg_logging_init(argv[0]);
     125         244 :     set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_resetwal"));
     126         244 :     progname = get_progname(argv[0]);
     127             : 
     128         244 :     if (argc > 1)
     129             :     {
     130         242 :         if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
     131             :         {
     132           2 :             usage();
     133           2 :             exit(0);
     134             :         }
     135         240 :         if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
     136             :         {
     137          60 :             puts("pg_resetwal (PostgreSQL) " PG_VERSION);
     138          60 :             exit(0);
     139             :         }
     140             :     }
     141             : 
     142             : 
     143         386 :     while ((c = getopt_long(argc, argv, "c:D:e:fl:m:no:O:u:x:", long_options, NULL)) != -1)
     144             :     {
     145         250 :         switch (c)
     146             :         {
     147           8 :             case 'D':
     148           8 :                 DataDir = optarg;
     149           8 :                 break;
     150             : 
     151          38 :             case 'f':
     152          38 :                 force = true;
     153          38 :                 break;
     154             : 
     155          52 :             case 'n':
     156          52 :                 noupdate = true;
     157          52 :                 break;
     158             : 
     159          18 :             case 'e':
     160          18 :                 errno = 0;
     161          18 :                 set_xid_epoch = strtoul(optarg, &endptr, 0);
     162          18 :                 if (endptr == optarg || *endptr != '\0' || errno != 0)
     163             :                 {
     164             :                     /*------
     165             :                       translator: the second %s is a command line argument (-e, etc) */
     166           2 :                     pg_log_error("invalid argument for option %s", "-e");
     167           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     168           2 :                     exit(1);
     169             :                 }
     170          16 :                 if (set_xid_epoch == -1)
     171           2 :                     pg_fatal("transaction ID epoch (-e) must not be -1");
     172          14 :                 break;
     173             : 
     174          16 :             case 'u':
     175          16 :                 errno = 0;
     176          16 :                 set_oldest_xid = strtoul(optarg, &endptr, 0);
     177          16 :                 if (endptr == optarg || *endptr != '\0' || errno != 0)
     178             :                 {
     179           2 :                     pg_log_error("invalid argument for option %s", "-u");
     180           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     181           2 :                     exit(1);
     182             :                 }
     183          14 :                 if (!TransactionIdIsNormal(set_oldest_xid))
     184           2 :                     pg_fatal("oldest transaction ID (-u) must be greater than or equal to %u", FirstNormalTransactionId);
     185          12 :                 break;
     186             : 
     187          16 :             case 'x':
     188          16 :                 errno = 0;
     189          16 :                 set_xid = strtoul(optarg, &endptr, 0);
     190          16 :                 if (endptr == optarg || *endptr != '\0' || errno != 0)
     191             :                 {
     192           2 :                     pg_log_error("invalid argument for option %s", "-x");
     193           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     194           2 :                     exit(1);
     195             :                 }
     196          14 :                 if (!TransactionIdIsNormal(set_xid))
     197           2 :                     pg_fatal("transaction ID (-x) must be greater than or equal to %u", FirstNormalTransactionId);
     198          12 :                 break;
     199             : 
     200          20 :             case 'c':
     201          20 :                 errno = 0;
     202          20 :                 set_oldest_commit_ts_xid = strtoul(optarg, &endptr, 0);
     203          20 :                 if (endptr == optarg || *endptr != ',' || errno != 0)
     204             :                 {
     205           2 :                     pg_log_error("invalid argument for option %s", "-c");
     206           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     207           2 :                     exit(1);
     208             :                 }
     209          18 :                 set_newest_commit_ts_xid = strtoul(endptr + 1, &endptr2, 0);
     210          18 :                 if (endptr2 == endptr + 1 || *endptr2 != '\0' || errno != 0)
     211             :                 {
     212           2 :                     pg_log_error("invalid argument for option %s", "-c");
     213           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     214           2 :                     exit(1);
     215             :                 }
     216             : 
     217          16 :                 if (set_oldest_commit_ts_xid < FirstNormalTransactionId &&
     218           2 :                     set_oldest_commit_ts_xid != InvalidTransactionId)
     219           2 :                     pg_fatal("transaction ID (-c) must be either %u or greater than or equal to %u", InvalidTransactionId, FirstNormalTransactionId);
     220             : 
     221          14 :                 if (set_newest_commit_ts_xid < FirstNormalTransactionId &&
     222           6 :                     set_newest_commit_ts_xid != InvalidTransactionId)
     223           2 :                     pg_fatal("transaction ID (-c) must be either %u or greater than or equal to %u", InvalidTransactionId, FirstNormalTransactionId);
     224          12 :                 break;
     225             : 
     226          16 :             case 'o':
     227          16 :                 errno = 0;
     228          16 :                 set_oid = strtoul(optarg, &endptr, 0);
     229          16 :                 if (endptr == optarg || *endptr != '\0' || errno != 0)
     230             :                 {
     231           2 :                     pg_log_error("invalid argument for option %s", "-o");
     232           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     233           2 :                     exit(1);
     234             :                 }
     235          14 :                 if (set_oid == 0)
     236           2 :                     pg_fatal("OID (-o) must not be 0");
     237          12 :                 break;
     238             : 
     239          20 :             case 'm':
     240          20 :                 errno = 0;
     241          20 :                 set_mxid = strtoul(optarg, &endptr, 0);
     242          20 :                 if (endptr == optarg || *endptr != ',' || errno != 0)
     243             :                 {
     244           2 :                     pg_log_error("invalid argument for option %s", "-m");
     245           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     246           2 :                     exit(1);
     247             :                 }
     248             : 
     249          18 :                 set_oldestmxid = strtoul(endptr + 1, &endptr2, 0);
     250          18 :                 if (endptr2 == endptr + 1 || *endptr2 != '\0' || errno != 0)
     251             :                 {
     252           2 :                     pg_log_error("invalid argument for option %s", "-m");
     253           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     254           2 :                     exit(1);
     255             :                 }
     256          16 :                 if (set_mxid == 0)
     257           2 :                     pg_fatal("multitransaction ID (-m) must not be 0");
     258             : 
     259             :                 /*
     260             :                  * XXX It'd be nice to have more sanity checks here, e.g. so
     261             :                  * that oldest is not wrapped around w.r.t. nextMulti.
     262             :                  */
     263          14 :                 if (set_oldestmxid == 0)
     264           2 :                     pg_fatal("oldest multitransaction ID (-m) must not be 0");
     265          12 :                 break;
     266             : 
     267          16 :             case 'O':
     268          16 :                 errno = 0;
     269          16 :                 set_mxoff = strtoul(optarg, &endptr, 0);
     270          16 :                 if (endptr == optarg || *endptr != '\0' || errno != 0)
     271             :                 {
     272           2 :                     pg_log_error("invalid argument for option %s", "-O");
     273           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     274           2 :                     exit(1);
     275             :                 }
     276          14 :                 if (set_mxoff == -1)
     277           2 :                     pg_fatal("multitransaction offset (-O) must not be -1");
     278          12 :                 break;
     279             : 
     280          14 :             case 'l':
     281          14 :                 if (strspn(optarg, "01234567890ABCDEFabcdef") != XLOG_FNAME_LEN)
     282             :                 {
     283           2 :                     pg_log_error("invalid argument for option %s", "-l");
     284           2 :                     pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     285           2 :                     exit(1);
     286             :                 }
     287             : 
     288             :                 /*
     289             :                  * XLogFromFileName requires wal segment size which is not yet
     290             :                  * set. Hence wal details are set later on.
     291             :                  */
     292          12 :                 log_fname = pg_strdup(optarg);
     293          12 :                 break;
     294             : 
     295           8 :             case 1:
     296             :                 {
     297             :                     int         wal_segsize_mb;
     298             : 
     299           8 :                     if (!option_parse_int(optarg, "--wal-segsize", 1, 1024, &wal_segsize_mb))
     300           2 :                         exit(1);
     301           6 :                     set_wal_segsize = wal_segsize_mb * 1024 * 1024;
     302           6 :                     if (!IsValidWalSegSize(set_wal_segsize))
     303           2 :                         pg_fatal("argument of %s must be a power of two between 1 and 1024", "--wal-segsize");
     304           4 :                     break;
     305             :                 }
     306             : 
     307           6 :             case 2:
     308             :                 {
     309           6 :                     errno = 0;
     310             : 
     311           6 :                     if (pg_strcasecmp(optarg, "signed") == 0)
     312           0 :                         set_char_signedness = 1;
     313           6 :                     else if (pg_strcasecmp(optarg, "unsigned") == 0)
     314           4 :                         set_char_signedness = 0;
     315             :                     else
     316             :                     {
     317           2 :                         pg_log_error("invalid argument for option %s", "--char-signedness");
     318           2 :                         pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     319           2 :                         exit(1);
     320             :                     }
     321           4 :                     break;
     322             :                 }
     323             : 
     324           2 :             default:
     325             :                 /* getopt_long already emitted a complaint */
     326           2 :                 pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     327           2 :                 exit(1);
     328             :         }
     329             :     }
     330             : 
     331         136 :     if (DataDir == NULL && optind < argc)
     332         126 :         DataDir = argv[optind++];
     333             : 
     334             :     /* Complain if any arguments remain */
     335         136 :     if (optind < argc)
     336             :     {
     337           2 :         pg_log_error("too many command-line arguments (first is \"%s\")",
     338             :                      argv[optind]);
     339           2 :         pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     340           2 :         exit(1);
     341             :     }
     342             : 
     343         134 :     if (DataDir == NULL)
     344             :     {
     345           2 :         pg_log_error("no data directory specified");
     346           2 :         pg_log_error_hint("Try \"%s --help\" for more information.", progname);
     347           2 :         exit(1);
     348             :     }
     349             : 
     350             :     /*
     351             :      * Don't allow pg_resetwal to be run as root, to avoid overwriting the
     352             :      * ownership of files in the data directory. We need only check for root
     353             :      * -- any other user won't have sufficient permissions to modify files in
     354             :      * the data directory.
     355             :      */
     356             : #ifndef WIN32
     357         132 :     if (geteuid() == 0)
     358             :     {
     359           0 :         pg_log_error("cannot be executed by \"root\"");
     360           0 :         pg_log_error_hint("You must run %s as the PostgreSQL superuser.",
     361             :                           progname);
     362           0 :         exit(1);
     363             :     }
     364             : #endif
     365             : 
     366         132 :     get_restricted_token();
     367             : 
     368             :     /* Set mask based on PGDATA permissions */
     369         132 :     if (!GetDataDirectoryCreatePerm(DataDir))
     370           2 :         pg_fatal("could not read permissions of directory \"%s\": %m",
     371             :                  DataDir);
     372             : 
     373         130 :     umask(pg_mode_mask);
     374             : 
     375         130 :     if (chdir(DataDir) < 0)
     376           0 :         pg_fatal("could not change directory to \"%s\": %m",
     377             :                  DataDir);
     378             : 
     379             :     /* Check that data directory matches our server version */
     380         130 :     CheckDataVersion();
     381             : 
     382             :     /*
     383             :      * Check for a postmaster lock file --- if there is one, refuse to
     384             :      * proceed, on grounds we might be interfering with a live installation.
     385             :      */
     386         130 :     if ((fd = open("postmaster.pid", O_RDONLY, 0)) < 0)
     387             :     {
     388         128 :         if (errno != ENOENT)
     389           0 :             pg_fatal("could not open file \"%s\" for reading: %m",
     390             :                      "postmaster.pid");
     391             :     }
     392             :     else
     393             :     {
     394           2 :         pg_log_error("lock file \"%s\" exists", "postmaster.pid");
     395           2 :         pg_log_error_hint("Is a server running?  If not, delete the lock file and try again.");
     396           2 :         exit(1);
     397             :     }
     398             : 
     399             :     /*
     400             :      * Attempt to read the existing pg_control file
     401             :      */
     402         128 :     if (!read_controlfile())
     403           8 :         GuessControlValues();
     404             : 
     405             :     /*
     406             :      * If no new WAL segment size was specified, use the control file value.
     407             :      */
     408         128 :     if (set_wal_segsize != 0)
     409           4 :         WalSegSz = set_wal_segsize;
     410             :     else
     411         124 :         WalSegSz = ControlFile.xlog_seg_size;
     412             : 
     413         128 :     if (log_fname != NULL)
     414          12 :         XLogFromFileName(log_fname, &minXlogTli, &minXlogSegNo, WalSegSz);
     415             : 
     416             :     /*
     417             :      * Also look at existing segment files to set up newXlogSegNo
     418             :      */
     419         128 :     FindEndOfXLOG();
     420             : 
     421             :     /*
     422             :      * If we're not going to proceed with the reset, print the current control
     423             :      * file parameters.
     424             :      */
     425         128 :     if ((guessed && !force) || noupdate)
     426          54 :         PrintControlValues(guessed);
     427             : 
     428             :     /*
     429             :      * Adjust fields if required by switches.  (Do this now so that printout,
     430             :      * if any, includes these values.)
     431             :      */
     432         128 :     if (set_xid_epoch != -1)
     433             :         ControlFile.checkPointCopy.nextXid =
     434          14 :             FullTransactionIdFromEpochAndXid(set_xid_epoch,
     435          14 :                                              XidFromFullTransactionId(ControlFile.checkPointCopy.nextXid));
     436             : 
     437         128 :     if (set_oldest_xid != 0)
     438             :     {
     439          12 :         ControlFile.checkPointCopy.oldestXid = set_oldest_xid;
     440          12 :         ControlFile.checkPointCopy.oldestXidDB = InvalidOid;
     441             :     }
     442             : 
     443         128 :     if (set_xid != 0)
     444             :         ControlFile.checkPointCopy.nextXid =
     445          12 :             FullTransactionIdFromEpochAndXid(EpochFromFullTransactionId(ControlFile.checkPointCopy.nextXid),
     446             :                                              set_xid);
     447             : 
     448         128 :     if (set_oldest_commit_ts_xid != 0)
     449          12 :         ControlFile.checkPointCopy.oldestCommitTsXid = set_oldest_commit_ts_xid;
     450         128 :     if (set_newest_commit_ts_xid != 0)
     451           8 :         ControlFile.checkPointCopy.newestCommitTsXid = set_newest_commit_ts_xid;
     452             : 
     453         128 :     if (set_oid != 0)
     454          12 :         ControlFile.checkPointCopy.nextOid = set_oid;
     455             : 
     456         128 :     if (set_mxid != 0)
     457             :     {
     458          12 :         ControlFile.checkPointCopy.nextMulti = set_mxid;
     459             : 
     460          12 :         ControlFile.checkPointCopy.oldestMulti = set_oldestmxid;
     461          12 :         if (ControlFile.checkPointCopy.oldestMulti < FirstMultiXactId)
     462           0 :             ControlFile.checkPointCopy.oldestMulti += FirstMultiXactId;
     463          12 :         ControlFile.checkPointCopy.oldestMultiDB = InvalidOid;
     464             :     }
     465             : 
     466         128 :     if (set_mxoff != -1)
     467          12 :         ControlFile.checkPointCopy.nextMultiOffset = set_mxoff;
     468             : 
     469         128 :     if (minXlogTli > ControlFile.checkPointCopy.ThisTimeLineID)
     470             :     {
     471           0 :         ControlFile.checkPointCopy.ThisTimeLineID = minXlogTli;
     472           0 :         ControlFile.checkPointCopy.PrevTimeLineID = minXlogTli;
     473             :     }
     474             : 
     475         128 :     if (set_wal_segsize != 0)
     476           4 :         ControlFile.xlog_seg_size = WalSegSz;
     477             : 
     478         128 :     if (set_char_signedness != -1)
     479           4 :         ControlFile.default_char_signedness = (set_char_signedness == 1);
     480             : 
     481         128 :     if (minXlogSegNo > newXlogSegNo)
     482           6 :         newXlogSegNo = minXlogSegNo;
     483             : 
     484         128 :     if (noupdate)
     485             :     {
     486          52 :         PrintNewControlValues();
     487          52 :         exit(0);
     488             :     }
     489             : 
     490             :     /*
     491             :      * If we had to guess anything, and -f was not given, just print the
     492             :      * guessed values and exit.
     493             :      */
     494          76 :     if (guessed && !force)
     495             :     {
     496           2 :         PrintNewControlValues();
     497           2 :         pg_log_error("not proceeding because control file values were guessed");
     498           2 :         pg_log_error_hint("If these values seem acceptable, use -f to force reset.");
     499           2 :         exit(1);
     500             :     }
     501             : 
     502             :     /*
     503             :      * Don't reset from a dirty pg_control without -f, either.
     504             :      */
     505          74 :     if (ControlFile.state != DB_SHUTDOWNED && !force)
     506             :     {
     507           2 :         pg_log_error("database server was not shut down cleanly");
     508           2 :         pg_log_error_detail("Resetting the write-ahead log might cause data to be lost.");
     509           2 :         pg_log_error_hint("If you want to proceed anyway, use -f to force reset.");
     510           2 :         exit(1);
     511             :     }
     512             : 
     513             :     /*
     514             :      * Else, do the dirty deed.
     515             :      */
     516          72 :     RewriteControlFile();
     517          72 :     KillExistingXLOG();
     518          72 :     KillExistingArchiveStatus();
     519          72 :     KillExistingWALSummaries();
     520          72 :     WriteEmptyXLOG();
     521             : 
     522          72 :     printf(_("Write-ahead log reset\n"));
     523          72 :     return 0;
     524             : }
     525             : 
     526             : 
     527             : /*
     528             :  * Look at the version string stored in PG_VERSION and decide if this utility
     529             :  * can be run safely or not.
     530             :  *
     531             :  * We don't want to inject pg_control and WAL files that are for a different
     532             :  * major version; that can't do anything good.  Note that we don't treat
     533             :  * mismatching version info in pg_control as a reason to bail out, because
     534             :  * recovering from a corrupted pg_control is one of the main reasons for this
     535             :  * program to exist at all.  However, PG_VERSION is unlikely to get corrupted,
     536             :  * and if it were it would be easy to fix by hand.  So let's make this check
     537             :  * to prevent simple user errors.
     538             :  */
     539             : static void
     540         130 : CheckDataVersion(void)
     541             : {
     542         130 :     const char *ver_file = "PG_VERSION";
     543             :     FILE       *ver_fd;
     544             :     char        rawline[64];
     545             : 
     546         130 :     if ((ver_fd = fopen(ver_file, "r")) == NULL)
     547           0 :         pg_fatal("could not open file \"%s\" for reading: %m",
     548             :                  ver_file);
     549             : 
     550             :     /* version number has to be the first line read */
     551         130 :     if (!fgets(rawline, sizeof(rawline), ver_fd))
     552             :     {
     553           0 :         if (!ferror(ver_fd))
     554           0 :             pg_fatal("unexpected empty file \"%s\"", ver_file);
     555             :         else
     556           0 :             pg_fatal("could not read file \"%s\": %m", ver_file);
     557             :     }
     558             : 
     559             :     /* strip trailing newline and carriage return */
     560         130 :     (void) pg_strip_crlf(rawline);
     561             : 
     562         130 :     if (strcmp(rawline, PG_MAJORVERSION) != 0)
     563             :     {
     564           0 :         pg_log_error("data directory is of wrong version");
     565           0 :         pg_log_error_detail("File \"%s\" contains \"%s\", which is not compatible with this program's version \"%s\".",
     566             :                             ver_file, rawline, PG_MAJORVERSION);
     567           0 :         exit(1);
     568             :     }
     569             : 
     570         130 :     fclose(ver_fd);
     571         130 : }
     572             : 
     573             : 
     574             : /*
     575             :  * Try to read the existing pg_control file.
     576             :  *
     577             :  * This routine is also responsible for updating old pg_control versions
     578             :  * to the current format.  (Currently we don't do anything of the sort.)
     579             :  */
     580             : static bool
     581         128 : read_controlfile(void)
     582             : {
     583             :     int         fd;
     584             :     int         len;
     585             :     char       *buffer;
     586             :     pg_crc32c   crc;
     587             : 
     588         128 :     if ((fd = open(XLOG_CONTROL_FILE, O_RDONLY | PG_BINARY, 0)) < 0)
     589             :     {
     590             :         /*
     591             :          * If pg_control is not there at all, or we can't read it, the odds
     592             :          * are we've been handed a bad DataDir path, so give up. User can do
     593             :          * "touch pg_control" to force us to proceed.
     594             :          */
     595           0 :         pg_log_error("could not open file \"%s\" for reading: %m",
     596             :                      XLOG_CONTROL_FILE);
     597           0 :         if (errno == ENOENT)
     598           0 :             pg_log_error_hint("If you are sure the data directory path is correct, execute\n"
     599             :                               "  touch %s\n"
     600             :                               "and try again.",
     601             :                               XLOG_CONTROL_FILE);
     602           0 :         exit(1);
     603             :     }
     604             : 
     605             :     /* Use malloc to ensure we have a maxaligned buffer */
     606         128 :     buffer = (char *) pg_malloc(PG_CONTROL_FILE_SIZE);
     607             : 
     608         128 :     len = read(fd, buffer, PG_CONTROL_FILE_SIZE);
     609         128 :     if (len < 0)
     610           0 :         pg_fatal("could not read file \"%s\": %m", XLOG_CONTROL_FILE);
     611         128 :     close(fd);
     612             : 
     613         128 :     if (len >= sizeof(ControlFileData) &&
     614         128 :         ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
     615             :     {
     616             :         /* Check the CRC. */
     617         126 :         INIT_CRC32C(crc);
     618         126 :         COMP_CRC32C(crc,
     619             :                     buffer,
     620             :                     offsetof(ControlFileData, crc));
     621         126 :         FIN_CRC32C(crc);
     622             : 
     623         126 :         if (!EQ_CRC32C(crc, ((ControlFileData *) buffer)->crc))
     624             :         {
     625             :             /* We will use the data but treat it as guessed. */
     626           6 :             pg_log_warning("pg_control exists but has invalid CRC; proceed with caution");
     627           6 :             guessed = true;
     628             :         }
     629             : 
     630         126 :         memcpy(&ControlFile, buffer, sizeof(ControlFile));
     631             : 
     632             :         /* return false if WAL segment size is not valid */
     633         126 :         if (!IsValidWalSegSize(ControlFile.xlog_seg_size))
     634             :         {
     635           6 :             pg_log_warning(ngettext("pg_control specifies invalid WAL segment size (%d byte); proceed with caution",
     636             :                                     "pg_control specifies invalid WAL segment size (%d bytes); proceed with caution",
     637             :                                     ControlFile.xlog_seg_size),
     638             :                            ControlFile.xlog_seg_size);
     639           6 :             return false;
     640             :         }
     641             : 
     642         120 :         return true;
     643             :     }
     644             : 
     645             :     /* Looks like it's a mess. */
     646           2 :     pg_log_warning("pg_control exists but is broken or wrong version; ignoring it");
     647           2 :     return false;
     648             : }
     649             : 
     650             : 
     651             : /*
     652             :  * Guess at pg_control values when we can't read the old ones.
     653             :  */
     654             : static void
     655           8 : GuessControlValues(void)
     656             : {
     657             :     uint64      sysidentifier;
     658             :     struct timeval tv;
     659             : 
     660             :     /*
     661             :      * Set up a completely default set of pg_control values.
     662             :      */
     663           8 :     guessed = true;
     664           8 :     memset(&ControlFile, 0, sizeof(ControlFile));
     665             : 
     666           8 :     ControlFile.pg_control_version = PG_CONTROL_VERSION;
     667           8 :     ControlFile.catalog_version_no = CATALOG_VERSION_NO;
     668             : 
     669             :     /*
     670             :      * Create a new unique installation identifier, since we can no longer use
     671             :      * any old XLOG records.  See notes in xlog.c about the algorithm.
     672             :      */
     673           8 :     gettimeofday(&tv, NULL);
     674           8 :     sysidentifier = ((uint64) tv.tv_sec) << 32;
     675           8 :     sysidentifier |= ((uint64) tv.tv_usec) << 12;
     676           8 :     sysidentifier |= getpid() & 0xFFF;
     677             : 
     678           8 :     ControlFile.system_identifier = sysidentifier;
     679             : 
     680           8 :     ControlFile.checkPointCopy.redo = SizeOfXLogLongPHD;
     681           8 :     ControlFile.checkPointCopy.ThisTimeLineID = 1;
     682           8 :     ControlFile.checkPointCopy.PrevTimeLineID = 1;
     683           8 :     ControlFile.checkPointCopy.fullPageWrites = false;
     684             :     ControlFile.checkPointCopy.nextXid =
     685           8 :         FullTransactionIdFromEpochAndXid(0, FirstNormalTransactionId);
     686           8 :     ControlFile.checkPointCopy.nextOid = FirstGenbkiObjectId;
     687           8 :     ControlFile.checkPointCopy.nextMulti = FirstMultiXactId;
     688           8 :     ControlFile.checkPointCopy.nextMultiOffset = 0;
     689           8 :     ControlFile.checkPointCopy.oldestXid = FirstNormalTransactionId;
     690           8 :     ControlFile.checkPointCopy.oldestXidDB = InvalidOid;
     691           8 :     ControlFile.checkPointCopy.oldestMulti = FirstMultiXactId;
     692           8 :     ControlFile.checkPointCopy.oldestMultiDB = InvalidOid;
     693           8 :     ControlFile.checkPointCopy.time = (pg_time_t) time(NULL);
     694           8 :     ControlFile.checkPointCopy.oldestActiveXid = InvalidTransactionId;
     695             : 
     696           8 :     ControlFile.state = DB_SHUTDOWNED;
     697           8 :     ControlFile.time = (pg_time_t) time(NULL);
     698           8 :     ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
     699           8 :     ControlFile.unloggedLSN = FirstNormalUnloggedLSN;
     700             : 
     701             :     /* minRecoveryPoint, backupStartPoint and backupEndPoint can be left zero */
     702             : 
     703           8 :     ControlFile.wal_level = WAL_LEVEL_MINIMAL;
     704           8 :     ControlFile.wal_log_hints = false;
     705           8 :     ControlFile.track_commit_timestamp = false;
     706           8 :     ControlFile.MaxConnections = 100;
     707           8 :     ControlFile.max_wal_senders = 10;
     708           8 :     ControlFile.max_worker_processes = 8;
     709           8 :     ControlFile.max_prepared_xacts = 0;
     710           8 :     ControlFile.max_locks_per_xact = 64;
     711             : 
     712           8 :     ControlFile.maxAlign = MAXIMUM_ALIGNOF;
     713           8 :     ControlFile.floatFormat = FLOATFORMAT_VALUE;
     714           8 :     ControlFile.blcksz = BLCKSZ;
     715           8 :     ControlFile.relseg_size = RELSEG_SIZE;
     716           8 :     ControlFile.xlog_blcksz = XLOG_BLCKSZ;
     717           8 :     ControlFile.xlog_seg_size = DEFAULT_XLOG_SEG_SIZE;
     718           8 :     ControlFile.nameDataLen = NAMEDATALEN;
     719           8 :     ControlFile.indexMaxKeys = INDEX_MAX_KEYS;
     720           8 :     ControlFile.toast_max_chunk_size = TOAST_MAX_CHUNK_SIZE;
     721           8 :     ControlFile.loblksize = LOBLKSIZE;
     722           8 :     ControlFile.float8ByVal = FLOAT8PASSBYVAL;
     723             : 
     724             :     /*
     725             :      * XXX eventually, should try to grovel through old XLOG to develop more
     726             :      * accurate values for TimeLineID, nextXID, etc.
     727             :      */
     728           8 : }
     729             : 
     730             : 
     731             : /*
     732             :  * Print the guessed pg_control values when we had to guess.
     733             :  *
     734             :  * NB: this display should be just those fields that will not be
     735             :  * reset by RewriteControlFile().
     736             :  */
     737             : static void
     738          54 : PrintControlValues(bool guessed)
     739             : {
     740          54 :     if (guessed)
     741           6 :         printf(_("Guessed pg_control values:\n\n"));
     742             :     else
     743          48 :         printf(_("Current pg_control values:\n\n"));
     744             : 
     745          54 :     printf(_("pg_control version number:            %u\n"),
     746             :            ControlFile.pg_control_version);
     747          54 :     printf(_("Catalog version number:               %u\n"),
     748             :            ControlFile.catalog_version_no);
     749          54 :     printf(_("Database system identifier:           %llu\n"),
     750             :            (unsigned long long) ControlFile.system_identifier);
     751          54 :     printf(_("Latest checkpoint's TimeLineID:       %u\n"),
     752             :            ControlFile.checkPointCopy.ThisTimeLineID);
     753          54 :     printf(_("Latest checkpoint's full_page_writes: %s\n"),
     754             :            ControlFile.checkPointCopy.fullPageWrites ? _("on") : _("off"));
     755          54 :     printf(_("Latest checkpoint's NextXID:          %u:%u\n"),
     756             :            EpochFromFullTransactionId(ControlFile.checkPointCopy.nextXid),
     757             :            XidFromFullTransactionId(ControlFile.checkPointCopy.nextXid));
     758          54 :     printf(_("Latest checkpoint's NextOID:          %u\n"),
     759             :            ControlFile.checkPointCopy.nextOid);
     760          54 :     printf(_("Latest checkpoint's NextMultiXactId:  %u\n"),
     761             :            ControlFile.checkPointCopy.nextMulti);
     762          54 :     printf(_("Latest checkpoint's NextMultiOffset:  %u\n"),
     763             :            ControlFile.checkPointCopy.nextMultiOffset);
     764          54 :     printf(_("Latest checkpoint's oldestXID:        %u\n"),
     765             :            ControlFile.checkPointCopy.oldestXid);
     766          54 :     printf(_("Latest checkpoint's oldestXID's DB:   %u\n"),
     767             :            ControlFile.checkPointCopy.oldestXidDB);
     768          54 :     printf(_("Latest checkpoint's oldestActiveXID:  %u\n"),
     769             :            ControlFile.checkPointCopy.oldestActiveXid);
     770          54 :     printf(_("Latest checkpoint's oldestMultiXid:   %u\n"),
     771             :            ControlFile.checkPointCopy.oldestMulti);
     772          54 :     printf(_("Latest checkpoint's oldestMulti's DB: %u\n"),
     773             :            ControlFile.checkPointCopy.oldestMultiDB);
     774          54 :     printf(_("Latest checkpoint's oldestCommitTsXid:%u\n"),
     775             :            ControlFile.checkPointCopy.oldestCommitTsXid);
     776          54 :     printf(_("Latest checkpoint's newestCommitTsXid:%u\n"),
     777             :            ControlFile.checkPointCopy.newestCommitTsXid);
     778          54 :     printf(_("Maximum data alignment:               %u\n"),
     779             :            ControlFile.maxAlign);
     780             :     /* we don't print floatFormat since can't say much useful about it */
     781          54 :     printf(_("Database block size:                  %u\n"),
     782             :            ControlFile.blcksz);
     783          54 :     printf(_("Blocks per segment of large relation: %u\n"),
     784             :            ControlFile.relseg_size);
     785          54 :     printf(_("WAL block size:                       %u\n"),
     786             :            ControlFile.xlog_blcksz);
     787          54 :     printf(_("Bytes per WAL segment:                %u\n"),
     788             :            ControlFile.xlog_seg_size);
     789          54 :     printf(_("Maximum length of identifiers:        %u\n"),
     790             :            ControlFile.nameDataLen);
     791          54 :     printf(_("Maximum columns in an index:          %u\n"),
     792             :            ControlFile.indexMaxKeys);
     793          54 :     printf(_("Maximum size of a TOAST chunk:        %u\n"),
     794             :            ControlFile.toast_max_chunk_size);
     795          54 :     printf(_("Size of a large-object chunk:         %u\n"),
     796             :            ControlFile.loblksize);
     797             :     /* This is no longer configurable, but users may still expect to see it: */
     798          54 :     printf(_("Date/time type storage:               %s\n"),
     799             :            _("64-bit integers"));
     800          54 :     printf(_("Float8 argument passing:              %s\n"),
     801             :            (ControlFile.float8ByVal ? _("by value") : _("by reference")));
     802          54 :     printf(_("Data page checksum version:           %u\n"),
     803             :            ControlFile.data_checksum_version);
     804          54 :     printf(_("Default char data signedness:         %s\n"),
     805             :            (ControlFile.default_char_signedness ? _("signed") : _("unsigned")));
     806          54 : }
     807             : 
     808             : 
     809             : /*
     810             :  * Print the values to be changed.
     811             :  */
     812             : static void
     813          54 : PrintNewControlValues(void)
     814             : {
     815             :     char        fname[MAXFNAMELEN];
     816             : 
     817             :     /* This will be always printed in order to keep format same. */
     818          54 :     printf(_("\n\nValues to be changed:\n\n"));
     819             : 
     820          54 :     XLogFileName(fname, ControlFile.checkPointCopy.ThisTimeLineID,
     821             :                  newXlogSegNo, WalSegSz);
     822          54 :     printf(_("First log segment after reset:        %s\n"), fname);
     823             : 
     824          54 :     if (set_mxid != 0)
     825             :     {
     826           2 :         printf(_("NextMultiXactId:                      %u\n"),
     827             :                ControlFile.checkPointCopy.nextMulti);
     828           2 :         printf(_("OldestMultiXid:                       %u\n"),
     829             :                ControlFile.checkPointCopy.oldestMulti);
     830           2 :         printf(_("OldestMulti's DB:                     %u\n"),
     831             :                ControlFile.checkPointCopy.oldestMultiDB);
     832             :     }
     833             : 
     834          54 :     if (set_mxoff != -1)
     835             :     {
     836           2 :         printf(_("NextMultiOffset:                      %u\n"),
     837             :                ControlFile.checkPointCopy.nextMultiOffset);
     838             :     }
     839             : 
     840          54 :     if (set_oid != 0)
     841             :     {
     842           2 :         printf(_("NextOID:                              %u\n"),
     843             :                ControlFile.checkPointCopy.nextOid);
     844             :     }
     845             : 
     846          54 :     if (set_xid != 0)
     847             :     {
     848           2 :         printf(_("NextXID:                              %u\n"),
     849             :                XidFromFullTransactionId(ControlFile.checkPointCopy.nextXid));
     850           2 :         printf(_("OldestXID:                            %u\n"),
     851             :                ControlFile.checkPointCopy.oldestXid);
     852           2 :         printf(_("OldestXID's DB:                       %u\n"),
     853             :                ControlFile.checkPointCopy.oldestXidDB);
     854             :     }
     855             : 
     856          54 :     if (set_xid_epoch != -1)
     857             :     {
     858           2 :         printf(_("NextXID epoch:                        %u\n"),
     859             :                EpochFromFullTransactionId(ControlFile.checkPointCopy.nextXid));
     860             :     }
     861             : 
     862          54 :     if (set_oldest_commit_ts_xid != 0)
     863             :     {
     864           2 :         printf(_("oldestCommitTsXid:                    %u\n"),
     865             :                ControlFile.checkPointCopy.oldestCommitTsXid);
     866             :     }
     867          54 :     if (set_newest_commit_ts_xid != 0)
     868             :     {
     869           0 :         printf(_("newestCommitTsXid:                    %u\n"),
     870             :                ControlFile.checkPointCopy.newestCommitTsXid);
     871             :     }
     872             : 
     873          54 :     if (set_wal_segsize != 0)
     874             :     {
     875           2 :         printf(_("Bytes per WAL segment:                %u\n"),
     876             :                ControlFile.xlog_seg_size);
     877             :     }
     878          54 : }
     879             : 
     880             : 
     881             : /*
     882             :  * Write out the new pg_control file.
     883             :  */
     884             : static void
     885          72 : RewriteControlFile(void)
     886             : {
     887             :     /*
     888             :      * Adjust fields as needed to force an empty XLOG starting at
     889             :      * newXlogSegNo.
     890             :      */
     891          72 :     XLogSegNoOffsetToRecPtr(newXlogSegNo, SizeOfXLogLongPHD, WalSegSz,
     892             :                             ControlFile.checkPointCopy.redo);
     893          72 :     ControlFile.checkPointCopy.time = (pg_time_t) time(NULL);
     894             : 
     895          72 :     ControlFile.state = DB_SHUTDOWNED;
     896          72 :     ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
     897          72 :     ControlFile.minRecoveryPoint = 0;
     898          72 :     ControlFile.minRecoveryPointTLI = 0;
     899          72 :     ControlFile.backupStartPoint = 0;
     900          72 :     ControlFile.backupEndPoint = 0;
     901          72 :     ControlFile.backupEndRequired = false;
     902             : 
     903             :     /*
     904             :      * Force the defaults for max_* settings. The values don't really matter
     905             :      * as long as wal_level='minimal'; the postmaster will reset these fields
     906             :      * anyway at startup.
     907             :      */
     908          72 :     ControlFile.wal_level = WAL_LEVEL_MINIMAL;
     909          72 :     ControlFile.wal_log_hints = false;
     910          72 :     ControlFile.track_commit_timestamp = false;
     911          72 :     ControlFile.MaxConnections = 100;
     912          72 :     ControlFile.max_wal_senders = 10;
     913          72 :     ControlFile.max_worker_processes = 8;
     914          72 :     ControlFile.max_prepared_xacts = 0;
     915          72 :     ControlFile.max_locks_per_xact = 64;
     916             : 
     917             :     /* The control file gets flushed here. */
     918          72 :     update_controlfile(".", &ControlFile, true);
     919          72 : }
     920             : 
     921             : 
     922             : /*
     923             :  * Scan existing XLOG files and determine the highest existing WAL address
     924             :  *
     925             :  * On entry, ControlFile.checkPointCopy.redo and ControlFile.xlog_seg_size
     926             :  * are assumed valid (note that we allow the old xlog seg size to differ
     927             :  * from what we're using).  On exit, newXlogSegNo is set to suitable
     928             :  * value for the beginning of replacement WAL (in our seg size).
     929             :  */
     930             : static void
     931         128 : FindEndOfXLOG(void)
     932             : {
     933             :     DIR        *xldir;
     934             :     struct dirent *xlde;
     935             :     uint64      xlogbytepos;
     936             : 
     937             :     /*
     938             :      * Initialize the max() computation using the last checkpoint address from
     939             :      * old pg_control.  Note that for the moment we are working with segment
     940             :      * numbering according to the old xlog seg size.
     941             :      */
     942         128 :     XLByteToSeg(ControlFile.checkPointCopy.redo, newXlogSegNo,
     943             :                 ControlFile.xlog_seg_size);
     944             : 
     945             :     /*
     946             :      * Scan the pg_wal directory to find existing WAL segment files. We assume
     947             :      * any present have been used; in most scenarios this should be
     948             :      * conservative, because of xlog.c's attempts to pre-create files.
     949             :      */
     950         128 :     xldir = opendir(XLOGDIR);
     951         128 :     if (xldir == NULL)
     952           0 :         pg_fatal("could not open directory \"%s\": %m", XLOGDIR);
     953             : 
     954        1066 :     while (errno = 0, (xlde = readdir(xldir)) != NULL)
     955             :     {
     956        1452 :         if (IsXLogFileName(xlde->d_name) ||
     957         514 :             IsPartialXLogFileName(xlde->d_name))
     958             :         {
     959             :             TimeLineID  tli;
     960             :             XLogSegNo   segno;
     961             : 
     962             :             /* Use the segment size from the control file */
     963         424 :             XLogFromFileName(xlde->d_name, &tli, &segno,
     964         424 :                              ControlFile.xlog_seg_size);
     965             : 
     966             :             /*
     967             :              * Note: we take the max of all files found, regardless of their
     968             :              * timelines.  Another possibility would be to ignore files of
     969             :              * timelines other than the target TLI, but this seems safer.
     970             :              * Better too large a result than too small...
     971             :              */
     972         424 :             if (segno > newXlogSegNo)
     973          76 :                 newXlogSegNo = segno;
     974             :         }
     975             :     }
     976             : 
     977         128 :     if (errno)
     978           0 :         pg_fatal("could not read directory \"%s\": %m", XLOGDIR);
     979             : 
     980         128 :     if (closedir(xldir))
     981           0 :         pg_fatal("could not close directory \"%s\": %m", XLOGDIR);
     982             : 
     983             :     /*
     984             :      * Finally, convert to new xlog seg size, and advance by one to ensure we
     985             :      * are in virgin territory.
     986             :      */
     987         128 :     xlogbytepos = newXlogSegNo * ControlFile.xlog_seg_size;
     988         128 :     newXlogSegNo = (xlogbytepos + ControlFile.xlog_seg_size - 1) / WalSegSz;
     989         128 :     newXlogSegNo++;
     990         128 : }
     991             : 
     992             : 
     993             : /*
     994             :  * Remove existing XLOG files
     995             :  */
     996             : static void
     997          72 : KillExistingXLOG(void)
     998             : {
     999             :     DIR        *xldir;
    1000             :     struct dirent *xlde;
    1001             :     char        path[MAXPGPATH + sizeof(XLOGDIR)];
    1002             : 
    1003          72 :     xldir = opendir(XLOGDIR);
    1004          72 :     if (xldir == NULL)
    1005           0 :         pg_fatal("could not open directory \"%s\": %m", XLOGDIR);
    1006             : 
    1007         478 :     while (errno = 0, (xlde = readdir(xldir)) != NULL)
    1008             :     {
    1009         696 :         if (IsXLogFileName(xlde->d_name) ||
    1010         290 :             IsPartialXLogFileName(xlde->d_name))
    1011             :         {
    1012         116 :             snprintf(path, sizeof(path), "%s/%s", XLOGDIR, xlde->d_name);
    1013         116 :             if (unlink(path) < 0)
    1014           0 :                 pg_fatal("could not delete file \"%s\": %m", path);
    1015             :         }
    1016             :     }
    1017             : 
    1018          72 :     if (errno)
    1019           0 :         pg_fatal("could not read directory \"%s\": %m", XLOGDIR);
    1020             : 
    1021          72 :     if (closedir(xldir))
    1022           0 :         pg_fatal("could not close directory \"%s\": %m", XLOGDIR);
    1023          72 : }
    1024             : 
    1025             : 
    1026             : /*
    1027             :  * Remove existing archive status files
    1028             :  */
    1029             : static void
    1030          72 : KillExistingArchiveStatus(void)
    1031             : {
    1032             : #define ARCHSTATDIR XLOGDIR "/archive_status"
    1033             : 
    1034             :     DIR        *xldir;
    1035             :     struct dirent *xlde;
    1036             :     char        path[MAXPGPATH + sizeof(ARCHSTATDIR)];
    1037             : 
    1038          72 :     xldir = opendir(ARCHSTATDIR);
    1039          72 :     if (xldir == NULL)
    1040           0 :         pg_fatal("could not open directory \"%s\": %m", ARCHSTATDIR);
    1041             : 
    1042         216 :     while (errno = 0, (xlde = readdir(xldir)) != NULL)
    1043             :     {
    1044         144 :         if (strspn(xlde->d_name, "0123456789ABCDEF") == XLOG_FNAME_LEN &&
    1045           0 :             (strcmp(xlde->d_name + XLOG_FNAME_LEN, ".ready") == 0 ||
    1046           0 :              strcmp(xlde->d_name + XLOG_FNAME_LEN, ".done") == 0 ||
    1047           0 :              strcmp(xlde->d_name + XLOG_FNAME_LEN, ".partial.ready") == 0 ||
    1048           0 :              strcmp(xlde->d_name + XLOG_FNAME_LEN, ".partial.done") == 0))
    1049             :         {
    1050           0 :             snprintf(path, sizeof(path), "%s/%s", ARCHSTATDIR, xlde->d_name);
    1051           0 :             if (unlink(path) < 0)
    1052           0 :                 pg_fatal("could not delete file \"%s\": %m", path);
    1053             :         }
    1054             :     }
    1055             : 
    1056          72 :     if (errno)
    1057           0 :         pg_fatal("could not read directory \"%s\": %m", ARCHSTATDIR);
    1058             : 
    1059          72 :     if (closedir(xldir))
    1060           0 :         pg_fatal("could not close directory \"%s\": %m", ARCHSTATDIR);
    1061          72 : }
    1062             : 
    1063             : /*
    1064             :  * Remove existing WAL summary files
    1065             :  */
    1066             : static void
    1067          72 : KillExistingWALSummaries(void)
    1068             : {
    1069             : #define WALSUMMARYDIR XLOGDIR   "/summaries"
    1070             : #define WALSUMMARY_NHEXCHARS    40
    1071             : 
    1072             :     DIR        *xldir;
    1073             :     struct dirent *xlde;
    1074             :     char        path[MAXPGPATH + sizeof(WALSUMMARYDIR)];
    1075             : 
    1076          72 :     xldir = opendir(WALSUMMARYDIR);
    1077          72 :     if (xldir == NULL)
    1078           0 :         pg_fatal("could not open directory \"%s\": %m", WALSUMMARYDIR);
    1079             : 
    1080         216 :     while (errno = 0, (xlde = readdir(xldir)) != NULL)
    1081             :     {
    1082         144 :         if (strspn(xlde->d_name, "0123456789ABCDEF") == WALSUMMARY_NHEXCHARS &&
    1083           0 :             strcmp(xlde->d_name + WALSUMMARY_NHEXCHARS, ".summary") == 0)
    1084             :         {
    1085           0 :             snprintf(path, sizeof(path), "%s/%s", WALSUMMARYDIR, xlde->d_name);
    1086           0 :             if (unlink(path) < 0)
    1087           0 :                 pg_fatal("could not delete file \"%s\": %m", path);
    1088             :         }
    1089             :     }
    1090             : 
    1091          72 :     if (errno)
    1092           0 :         pg_fatal("could not read directory \"%s\": %m", WALSUMMARYDIR);
    1093             : 
    1094          72 :     if (closedir(xldir))
    1095           0 :         pg_fatal("could not close directory \"%s\": %m", ARCHSTATDIR);
    1096          72 : }
    1097             : 
    1098             : /*
    1099             :  * Write an empty XLOG file, containing only the checkpoint record
    1100             :  * already set up in ControlFile.
    1101             :  */
    1102             : static void
    1103          72 : WriteEmptyXLOG(void)
    1104             : {
    1105             :     PGAlignedXLogBlock buffer;
    1106             :     XLogPageHeader page;
    1107             :     XLogLongPageHeader longpage;
    1108             :     XLogRecord *record;
    1109             :     pg_crc32c   crc;
    1110             :     char        path[MAXPGPATH];
    1111             :     int         fd;
    1112             :     int         nbytes;
    1113             :     char       *recptr;
    1114             : 
    1115          72 :     memset(buffer.data, 0, XLOG_BLCKSZ);
    1116             : 
    1117             :     /* Set up the XLOG page header */
    1118          72 :     page = (XLogPageHeader) buffer.data;
    1119          72 :     page->xlp_magic = XLOG_PAGE_MAGIC;
    1120          72 :     page->xlp_info = XLP_LONG_HEADER;
    1121          72 :     page->xlp_tli = ControlFile.checkPointCopy.ThisTimeLineID;
    1122          72 :     page->xlp_pageaddr = ControlFile.checkPointCopy.redo - SizeOfXLogLongPHD;
    1123          72 :     longpage = (XLogLongPageHeader) page;
    1124          72 :     longpage->xlp_sysid = ControlFile.system_identifier;
    1125          72 :     longpage->xlp_seg_size = WalSegSz;
    1126          72 :     longpage->xlp_xlog_blcksz = XLOG_BLCKSZ;
    1127             : 
    1128             :     /* Insert the initial checkpoint record */
    1129          72 :     recptr = (char *) page + SizeOfXLogLongPHD;
    1130          72 :     record = (XLogRecord *) recptr;
    1131          72 :     record->xl_prev = 0;
    1132          72 :     record->xl_xid = InvalidTransactionId;
    1133          72 :     record->xl_tot_len = SizeOfXLogRecord + SizeOfXLogRecordDataHeaderShort + sizeof(CheckPoint);
    1134          72 :     record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
    1135          72 :     record->xl_rmid = RM_XLOG_ID;
    1136             : 
    1137          72 :     recptr += SizeOfXLogRecord;
    1138          72 :     *(recptr++) = (char) XLR_BLOCK_ID_DATA_SHORT;
    1139          72 :     *(recptr++) = sizeof(CheckPoint);
    1140          72 :     memcpy(recptr, &ControlFile.checkPointCopy,
    1141             :            sizeof(CheckPoint));
    1142             : 
    1143          72 :     INIT_CRC32C(crc);
    1144          72 :     COMP_CRC32C(crc, ((char *) record) + SizeOfXLogRecord, record->xl_tot_len - SizeOfXLogRecord);
    1145          72 :     COMP_CRC32C(crc, (char *) record, offsetof(XLogRecord, xl_crc));
    1146          72 :     FIN_CRC32C(crc);
    1147          72 :     record->xl_crc = crc;
    1148             : 
    1149             :     /* Write the first page */
    1150          72 :     XLogFilePath(path, ControlFile.checkPointCopy.ThisTimeLineID,
    1151             :                  newXlogSegNo, WalSegSz);
    1152             : 
    1153          72 :     unlink(path);
    1154             : 
    1155          72 :     fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
    1156             :               pg_file_create_mode);
    1157          72 :     if (fd < 0)
    1158           0 :         pg_fatal("could not open file \"%s\": %m", path);
    1159             : 
    1160          72 :     errno = 0;
    1161          72 :     if (write(fd, buffer.data, XLOG_BLCKSZ) != XLOG_BLCKSZ)
    1162             :     {
    1163             :         /* if write didn't set errno, assume problem is no disk space */
    1164           0 :         if (errno == 0)
    1165           0 :             errno = ENOSPC;
    1166           0 :         pg_fatal("could not write file \"%s\": %m", path);
    1167             :     }
    1168             : 
    1169             :     /* Fill the rest of the file with zeroes */
    1170          72 :     memset(buffer.data, 0, XLOG_BLCKSZ);
    1171      116736 :     for (nbytes = XLOG_BLCKSZ; nbytes < WalSegSz; nbytes += XLOG_BLCKSZ)
    1172             :     {
    1173      116664 :         errno = 0;
    1174      116664 :         if (write(fd, buffer.data, XLOG_BLCKSZ) != XLOG_BLCKSZ)
    1175             :         {
    1176           0 :             if (errno == 0)
    1177           0 :                 errno = ENOSPC;
    1178           0 :             pg_fatal("could not write file \"%s\": %m", path);
    1179             :         }
    1180             :     }
    1181             : 
    1182          72 :     if (fsync(fd) != 0)
    1183           0 :         pg_fatal("fsync error: %m");
    1184             : 
    1185          72 :     close(fd);
    1186          72 : }
    1187             : 
    1188             : 
    1189             : static void
    1190           2 : usage(void)
    1191             : {
    1192           2 :     printf(_("%s resets the PostgreSQL write-ahead log.\n\n"), progname);
    1193           2 :     printf(_("Usage:\n"));
    1194           2 :     printf(_("  %s [OPTION]... DATADIR\n"), progname);
    1195             : 
    1196           2 :     printf(_("\nOptions:\n"));
    1197           2 :     printf(_(" [-D, --pgdata=]DATADIR  data directory\n"));
    1198           2 :     printf(_("  -f, --force            force update to be done even after unclean shutdown or\n"
    1199             :              "                         if pg_control values had to be guessed\n"));
    1200           2 :     printf(_("  -n, --dry-run          no update, just show what would be done\n"));
    1201           2 :     printf(_("  -V, --version          output version information, then exit\n"));
    1202           2 :     printf(_("  -?, --help             show this help, then exit\n"));
    1203             : 
    1204           2 :     printf(_("\nOptions to override control file values:\n"));
    1205           2 :     printf(_("  -c, --commit-timestamp-ids=XID,XID\n"
    1206             :              "                                   set oldest and newest transactions bearing\n"
    1207             :              "                                   commit timestamp (zero means no change)\n"));
    1208           2 :     printf(_("  -e, --epoch=XIDEPOCH             set next transaction ID epoch\n"));
    1209           2 :     printf(_("  -l, --next-wal-file=WALFILE      set minimum starting location for new WAL\n"));
    1210           2 :     printf(_("  -m, --multixact-ids=MXID,MXID    set next and oldest multitransaction ID\n"));
    1211           2 :     printf(_("  -o, --next-oid=OID               set next OID\n"));
    1212           2 :     printf(_("  -O, --multixact-offset=OFFSET    set next multitransaction offset\n"));
    1213           2 :     printf(_("  -u, --oldest-transaction-id=XID  set oldest transaction ID\n"));
    1214           2 :     printf(_("  -x, --next-transaction-id=XID    set next transaction ID\n"));
    1215           2 :     printf(_("      --char-signedness=OPTION     set char signedness to \"signed\"  or \"unsigned\"\n"));
    1216           2 :     printf(_("      --wal-segsize=SIZE           size of WAL segments, in megabytes\n"));
    1217             : 
    1218           2 :     printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    1219           2 :     printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
    1220           2 : }

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