granicus.if.org Git - postgresql/blob - src/backend/utils/init/miscinit.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * miscinit.c
   4  *        miscellaneous initialization support stuff
   5  *
   6  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.138 2005/03/18 03:48:49 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include <sys/param.h>
  18 #include <signal.h>
  19 #include <sys/file.h>
  20 #include <sys/stat.h>
  21 #include <sys/time.h>
  22 #include <fcntl.h>
  23 #include <unistd.h>
  24 #include <grp.h>
  25 #include <pwd.h>
  26 #include <netinet/in.h>
  27 #include <arpa/inet.h>
  28 #ifdef HAVE_UTIME_H
  29 #include <utime.h>
  30 #endif
  31
  32 #include "catalog/catname.h"
  33 #include "catalog/pg_shadow.h"
  34 #include "libpq/libpq-be.h"
  35 #include "miscadmin.h"
  36 #include "storage/fd.h"
  37 #include "storage/ipc.h"
  38 #include "storage/pg_shmem.h"
  39 #include "utils/builtins.h"
  40 #include "utils/guc.h"
  41 #include "utils/lsyscache.h"
  42 #include "utils/syscache.h"
  43
  44
  45 ProcessingMode Mode = InitProcessing;
  46
  47 /* Note: we rely on these to initialize as zeroes */
  48 static char directoryLockFile[MAXPGPATH];
  49 static char socketLockFile[MAXPGPATH];
  50
  51
  52 /* ----------------------------------------------------------------
  53  *              ignoring system indexes support stuff
  54  *
  55  * NOTE: "ignoring system indexes" means we do not use the system indexes
  56  * for lookups (either in hardwired catalog accesses or in planner-generated
  57  * plans).      We do, however, still update the indexes when a catalog
  58  * modification is made.
  59  * ----------------------------------------------------------------
  60  */
  61
  62 static bool isIgnoringSystemIndexes = false;
  63
  64 /*
  65  * IsIgnoringSystemIndexes
  66  *              True if ignoring system indexes.
  67  */
  68 bool
  69 IsIgnoringSystemIndexes(void)
  70 {
  71         return isIgnoringSystemIndexes;
  72 }
  73
  74 /*
  75  * IgnoreSystemIndexes
  76  *              Set true or false whether PostgreSQL ignores system indexes.
  77  */
  78 void
  79 IgnoreSystemIndexes(bool mode)
  80 {
  81         isIgnoringSystemIndexes = mode;
  82 }
  83
  84 /* ----------------------------------------------------------------
  85  *              system index reindexing support
  86  *
  87  * When we are busy reindexing a system index, this code provides support
  88  * for preventing catalog lookups from using that index.
  89  * ----------------------------------------------------------------
  90  */
  91
  92 static Oid      currentlyReindexedHeap = InvalidOid;
  93 static Oid      currentlyReindexedIndex = InvalidOid;
  94
  95 /*
  96  * ReindexIsProcessingHeap
  97  *              True if heap specified by OID is currently being reindexed.
  98  */
  99 bool
 100 ReindexIsProcessingHeap(Oid heapOid)
 101 {
 102         return heapOid == currentlyReindexedHeap;
 103 }
 104
 105 /*
 106  * ReindexIsProcessingIndex
 107  *              True if index specified by OID is currently being reindexed.
 108  */
 109 bool
 110 ReindexIsProcessingIndex(Oid indexOid)
 111 {
 112         return indexOid == currentlyReindexedIndex;
 113 }
 114
 115 /*
 116  * SetReindexProcessing
 117  *              Set flag that specified heap/index are being reindexed.
 118  */
 119 void
 120 SetReindexProcessing(Oid heapOid, Oid indexOid)
 121 {
 122         Assert(OidIsValid(heapOid) && OidIsValid(indexOid));
 123         /* Reindexing is not re-entrant. */
 124         if (OidIsValid(currentlyReindexedIndex))
 125                 elog(ERROR, "cannot reindex while reindexing");
 126         currentlyReindexedHeap = heapOid;
 127         currentlyReindexedIndex = indexOid;
 128 }
 129
 130 /*
 131  * ResetReindexProcessing
 132  *              Unset reindexing status.
 133  */
 134 void
 135 ResetReindexProcessing(void)
 136 {
 137         currentlyReindexedHeap = InvalidOid;
 138         currentlyReindexedIndex = InvalidOid;
 139 }
 140
 141 /* ----------------------------------------------------------------
 142  *                              database path / name support stuff
 143  * ----------------------------------------------------------------
 144  */
 145
 146 void
 147 SetDatabasePath(const char *path)
 148 {
 149         if (DatabasePath)
 150         {
 151                 free(DatabasePath);
 152                 DatabasePath = NULL;
 153         }
 154         /* use strdup since this is done before memory contexts are set up */
 155         if (path)
 156         {
 157                 DatabasePath = strdup(path);
 158                 AssertState(DatabasePath);
 159         }
 160 }
 161
 162 /*
 163  * Set data directory, but make sure it's an absolute path.  Use this,
 164  * never set DataDir directly.
 165  */
 166 void
 167 SetDataDir(const char *dir)
 168 {
 169         char       *new;
 170
 171         AssertArg(dir);
 172
 173         /* If presented path is relative, convert to absolute */
 174         new = make_absolute_path(dir);
 175
 176         if (DataDir)
 177                 free(DataDir);
 178         DataDir = new;
 179 }
 180
 181 /*
 182  * If the given pathname isn't already absolute, make it so, interpreting
 183  * it relative to the current working directory.
 184  *
 185  * Also canonicalizes the path.  The result is always a malloc'd copy.
 186  *
 187  * Note: it is probably unwise to use this in running backends, since they
 188  * have chdir'd to a database-specific subdirectory; the results would not be
 189  * consistent across backends.  Currently this is used only during postmaster
 190  * or standalone-backend startup.
 191  */
 192 char *
 193 make_absolute_path(const char *path)
 194 {
 195         char       *new;
 196
 197         /* Returning null for null input is convenient for some callers */
 198         if (path == NULL)
 199                 return NULL;
 200
 201         if (!is_absolute_path(path))
 202         {
 203                 char       *buf;
 204                 size_t          buflen;
 205
 206                 buflen = MAXPGPATH;
 207                 for (;;)
 208                 {
 209                         buf = malloc(buflen);
 210                         if (!buf)
 211                                 ereport(FATAL,
 212                                                 (errcode(ERRCODE_OUT_OF_MEMORY),
 213                                                  errmsg("out of memory")));
 214
 215                         if (getcwd(buf, buflen))
 216                                 break;
 217                         else if (errno == ERANGE)
 218                         {
 219                                 free(buf);
 220                                 buflen *= 2;
 221                                 continue;
 222                         }
 223                         else
 224                         {
 225                                 free(buf);
 226                                 elog(FATAL, "could not get current working directory: %m");
 227                         }
 228                 }
 229
 230                 new = malloc(strlen(buf) + strlen(path) + 2);
 231                 if (!new)
 232                         ereport(FATAL,
 233                                         (errcode(ERRCODE_OUT_OF_MEMORY),
 234                                          errmsg("out of memory")));
 235                 sprintf(new, "%s/%s", buf, path);
 236                 free(buf);
 237         }
 238         else
 239         {
 240                 new = strdup(path);
 241                 if (!new)
 242                         ereport(FATAL,
 243                                         (errcode(ERRCODE_OUT_OF_MEMORY),
 244                                          errmsg("out of memory")));
 245         }
 246
 247         /* Make sure punctuation is canonical, too */
 248         canonicalize_path(new);
 249
 250         return new;
 251 }
 252
 253
 254 /* ----------------------------------------------------------------
 255  *      User ID things
 256  *
 257  * The authenticated user is determined at connection start and never
 258  * changes.  The session user can be changed only by SET SESSION
 259  * AUTHORIZATION.  The current user may change when "setuid" functions
 260  * are implemented.  Conceptually there is a stack, whose bottom
 261  * is the session user.  You are yourself responsible to save and
 262  * restore the current user id if you need to change it.
 263  * ----------------------------------------------------------------
 264  */
 265 static AclId AuthenticatedUserId = 0;
 266 static AclId SessionUserId = 0;
 267 static AclId CurrentUserId = 0;
 268
 269 static bool AuthenticatedUserIsSuperuser = false;
 270
 271 /*
 272  * This function is relevant for all privilege checks.
 273  */
 274 AclId
 275 GetUserId(void)
 276 {
 277         AssertState(AclIdIsValid(CurrentUserId));
 278         return CurrentUserId;
 279 }
 280
 281
 282 void
 283 SetUserId(AclId newid)
 284 {
 285         AssertArg(AclIdIsValid(newid));
 286         CurrentUserId = newid;
 287 }
 288
 289
 290 /*
 291  * This value is only relevant for informational purposes.
 292  */
 293 AclId
 294 GetSessionUserId(void)
 295 {
 296         AssertState(AclIdIsValid(SessionUserId));
 297         return SessionUserId;
 298 }
 299
 300
 301 void
 302 SetSessionUserId(AclId newid)
 303 {
 304         AssertArg(AclIdIsValid(newid));
 305         SessionUserId = newid;
 306         /* Current user defaults to session user. */
 307         if (!AclIdIsValid(CurrentUserId))
 308                 CurrentUserId = newid;
 309 }
 310
 311
 312 void
 313 InitializeSessionUserId(const char *username)
 314 {
 315         HeapTuple       userTup;
 316         Datum           datum;
 317         bool            isnull;
 318         AclId           usesysid;
 319
 320         /*
 321          * Don't do scans if we're bootstrapping, none of the system catalogs
 322          * exist yet, and they should be owned by postgres anyway.
 323          */
 324         AssertState(!IsBootstrapProcessingMode());
 325
 326         /* call only once */
 327         AssertState(!OidIsValid(AuthenticatedUserId));
 328
 329         userTup = SearchSysCache(SHADOWNAME,
 330                                                          PointerGetDatum(username),
 331                                                          0, 0, 0);
 332         if (!HeapTupleIsValid(userTup))
 333                 ereport(FATAL,
 334                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 335                                  errmsg("user \"%s\" does not exist", username)));
 336
 337         usesysid = ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid;
 338
 339         AuthenticatedUserId = usesysid;
 340         AuthenticatedUserIsSuperuser = ((Form_pg_shadow) GETSTRUCT(userTup))->usesuper;
 341
 342         SetSessionUserId(usesysid); /* sets CurrentUserId too */
 343
 344         /* Record username and superuser status as GUC settings too */
 345         SetConfigOption("session_authorization", username,
 346                                         PGC_BACKEND, PGC_S_OVERRIDE);
 347         SetConfigOption("is_superuser",
 348                                         AuthenticatedUserIsSuperuser ? "on" : "off",
 349                                         PGC_INTERNAL, PGC_S_OVERRIDE);
 350
 351         /*
 352          * Set up user-specific configuration variables.  This is a good place
 353          * to do it so we don't have to read pg_shadow twice during session
 354          * startup.
 355          */
 356         datum = SysCacheGetAttr(SHADOWNAME, userTup,
 357                                                         Anum_pg_shadow_useconfig, &isnull);
 358         if (!isnull)
 359         {
 360                 ArrayType  *a = DatumGetArrayTypeP(datum);
 361
 362                 ProcessGUCArray(a, PGC_S_USER);
 363         }
 364
 365         ReleaseSysCache(userTup);
 366 }
 367
 368
 369 void
 370 InitializeSessionUserIdStandalone(void)
 371 {
 372         /* This function should only be called in a single-user backend. */
 373         AssertState(!IsUnderPostmaster);
 374
 375         /* call only once */
 376         AssertState(!OidIsValid(AuthenticatedUserId));
 377
 378         AuthenticatedUserId = BOOTSTRAP_USESYSID;
 379         AuthenticatedUserIsSuperuser = true;
 380
 381         SetSessionUserId(BOOTSTRAP_USESYSID);
 382 }
 383
 384
 385 /*
 386  * Change session auth ID while running
 387  *
 388  * Only a superuser may set auth ID to something other than himself.  Note
 389  * that in case of multiple SETs in a single session, the original userid's
 390  * superuserness is what matters.  But we set the GUC variable is_superuser
 391  * to indicate whether the *current* session userid is a superuser.
 392  */
 393 void
 394 SetSessionAuthorization(AclId userid, bool is_superuser)
 395 {
 396         /* Must have authenticated already, else can't make permission check */
 397         AssertState(AclIdIsValid(AuthenticatedUserId));
 398
 399         if (userid != AuthenticatedUserId &&
 400                 !AuthenticatedUserIsSuperuser)
 401                 ereport(ERROR,
 402                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 403                           errmsg("permission denied to set session authorization")));
 404
 405         SetSessionUserId(userid);
 406         SetUserId(userid);
 407
 408         SetConfigOption("is_superuser",
 409                                         is_superuser ? "on" : "off",
 410                                         PGC_INTERNAL, PGC_S_OVERRIDE);
 411 }
 412
 413
 414 /*
 415  * Get user name from user id
 416  */
 417 char *
 418 GetUserNameFromId(AclId userid)
 419 {
 420         HeapTuple       tuple;
 421         char       *result;
 422
 423         tuple = SearchSysCache(SHADOWSYSID,
 424                                                    ObjectIdGetDatum(userid),
 425                                                    0, 0, 0);
 426         if (!HeapTupleIsValid(tuple))
 427                 ereport(ERROR,
 428                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 429                                  errmsg("invalid user ID: %d", userid)));
 430
 431         result = pstrdup(NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename));
 432
 433         ReleaseSysCache(tuple);
 434         return result;
 435 }
 436
 437
 438
 439 /*-------------------------------------------------------------------------
 440  *                              Interlock-file support
 441  *
 442  * These routines are used to create both a data-directory lockfile
 443  * ($DATADIR/postmaster.pid) and a Unix-socket-file lockfile ($SOCKFILE.lock).
 444  * Both kinds of files contain the same info:
 445  *
 446  *              Owning process' PID
 447  *              Data directory path
 448  *
 449  * By convention, the owning process' PID is negated if it is a standalone
 450  * backend rather than a postmaster.  This is just for informational purposes.
 451  * The path is also just for informational purposes (so that a socket lockfile
 452  * can be more easily traced to the associated postmaster).
 453  *
 454  * A data-directory lockfile can optionally contain a third line, containing
 455  * the key and ID for the shared memory block used by this postmaster.
 456  *
 457  * On successful lockfile creation, a proc_exit callback to remove the
 458  * lockfile is automatically created.
 459  *-------------------------------------------------------------------------
 460  */
 461
 462 /*
 463  * proc_exit callback to remove a lockfile.
 464  */
 465 static void
 466 UnlinkLockFile(int status, Datum filename)
 467 {
 468         char       *fname = (char *) DatumGetPointer(filename);
 469
 470         if (fname != NULL)
 471         {
 472                 if (unlink(fname) != 0)
 473                 {
 474                         /* Should we complain if the unlink fails? */
 475                 }
 476                 free(fname);
 477         }
 478 }
 479
 480 /*
 481  * Create a lockfile.
 482  *
 483  * filename is the name of the lockfile to create.
 484  * amPostmaster is used to determine how to encode the output PID.
 485  * isDDLock and refName are used to determine what error message to produce.
 486  */
 487 static void
 488 CreateLockFile(const char *filename, bool amPostmaster,
 489                            bool isDDLock, const char *refName)
 490 {
 491         int                     fd;
 492         char            buffer[MAXPGPATH + 100];
 493         int                     ntries;
 494         int                     len;
 495         int                     encoded_pid;
 496         pid_t           other_pid;
 497         pid_t           my_pid = getpid();
 498
 499         /*
 500          * We need a loop here because of race conditions.      But don't loop
 501          * forever (for example, a non-writable $PGDATA directory might cause
 502          * a failure that won't go away).  100 tries seems like plenty.
 503          */
 504         for (ntries = 0;; ntries++)
 505         {
 506                 /*
 507                  * Try to create the lock file --- O_EXCL makes this atomic.
 508                  *
 509                  * Think not to make the file protection weaker than 0600.  See
 510                  * comments below.
 511                  */
 512                 fd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
 513                 if (fd >= 0)
 514                         break;                          /* Success; exit the retry loop */
 515
 516                 /*
 517                  * Couldn't create the pid file. Probably it already exists.
 518                  */
 519                 if ((errno != EEXIST && errno != EACCES) || ntries > 100)
 520                         ereport(FATAL,
 521                                         (errcode_for_file_access(),
 522                                          errmsg("could not create lock file \"%s\": %m",
 523                                                         filename)));
 524
 525                 /*
 526                  * Read the file to get the old owner's PID.  Note race condition
 527                  * here: file might have been deleted since we tried to create it.
 528                  */
 529                 fd = open(filename, O_RDONLY, 0600);
 530                 if (fd < 0)
 531                 {
 532                         if (errno == ENOENT)
 533                                 continue;               /* race condition; try again */
 534                         ereport(FATAL,
 535                                         (errcode_for_file_access(),
 536                                          errmsg("could not open lock file \"%s\": %m",
 537                                                         filename)));
 538                 }
 539                 if ((len = read(fd, buffer, sizeof(buffer) - 1)) < 0)
 540                         ereport(FATAL,
 541                                         (errcode_for_file_access(),
 542                                          errmsg("could not read lock file \"%s\": %m",
 543                                                         filename)));
 544                 close(fd);
 545
 546                 buffer[len] = '\0';
 547                 encoded_pid = atoi(buffer);
 548
 549                 /* if pid < 0, the pid is for postgres, not postmaster */
 550                 other_pid = (pid_t) (encoded_pid < 0 ? -encoded_pid : encoded_pid);
 551
 552                 if (other_pid <= 0)
 553                         elog(FATAL, "bogus data in lock file \"%s\"", filename);
 554
 555                 /*
 556                  * Check to see if the other process still exists
 557                  *
 558                  * If the PID in the lockfile is our own PID or our parent's PID,
 559                  * then the file must be stale (probably left over from a previous
 560                  * system boot cycle).  We need this test because of the likelihood
 561                  * that a reboot will assign exactly the same PID as we had in the
 562                  * previous reboot.  Also, if there is just one more process launch
 563                  * in this reboot than in the previous one, the lockfile might mention
 564                  * our parent's PID.  We can reject that since we'd never be launched
 565                  * directly by a competing postmaster.  We can't detect grandparent
 566                  * processes unfortunately, but if the init script is written carefully
 567                  * then all but the immediate parent shell will be root-owned processes
 568                  * and so the kill test will fail with EPERM.
 569                  *
 570                  * We can treat the EPERM-error case as okay because that error implies
 571                  * that the existing process has a different userid than we do, which
 572                  * means it cannot be a competing postmaster.  A postmaster cannot
 573                  * successfully attach to a data directory owned by a userid other
 574                  * than its own.  (This is now checked directly in checkDataDir(),
 575                  * but has been true for a long time because of the restriction that
 576                  * the data directory isn't group- or world-accessible.)  Also,
 577                  * since we create the lockfiles mode 600, we'd have failed above
 578                  * if the lockfile belonged to another userid --- which means that
 579                  * whatever process kill() is reporting about isn't the one that
 580                  * made the lockfile.  (NOTE: this last consideration is the only
 581                  * one that keeps us from blowing away a Unix socket file belonging
 582                  * to an instance of Postgres being run by someone else, at least
 583                  * on machines where /tmp hasn't got a stickybit.)
 584                  *
 585                  * Windows hasn't got getppid(), but doesn't need it since it's not
 586                  * using real kill() either...
 587                  *
 588                  * Normally kill() will fail with ESRCH if the given PID doesn't
 589                  * exist.  BeOS returns EINVAL for some silly reason, however.
 590                  */
 591                 if (other_pid != my_pid
 592 #ifndef WIN32
 593                         && other_pid != getppid()
 594 #endif
 595                         )
 596                 {
 597                         if (kill(other_pid, 0) == 0 ||
 598                                 (errno != ESRCH &&
 599 #ifdef __BEOS__
 600                                  errno != EINVAL &&
 601 #endif
 602                                  errno != EPERM))
 603                         {
 604                                 /* lockfile belongs to a live process */
 605                                 ereport(FATAL,
 606                                                 (errcode(ERRCODE_LOCK_FILE_EXISTS),
 607                                                  errmsg("lock file \"%s\" already exists",
 608                                                                 filename),
 609                                                  isDDLock ?
 610                                                  (encoded_pid < 0 ?
 611                                                   errhint("Is another postgres (PID %d) running in data directory \"%s\"?",
 612                                                                   (int) other_pid, refName) :
 613                                                   errhint("Is another postmaster (PID %d) running in data directory \"%s\"?",
 614                                                                   (int) other_pid, refName)) :
 615                                                  (encoded_pid < 0 ?
 616                                                   errhint("Is another postgres (PID %d) using socket file \"%s\"?",
 617                                                                   (int) other_pid, refName) :
 618                                                   errhint("Is another postmaster (PID %d) using socket file \"%s\"?",
 619                                                                   (int) other_pid, refName))));
 620                         }
 621                 }
 622
 623                 /*
 624                  * No, the creating process did not exist.      However, it could be
 625                  * that the postmaster crashed (or more likely was kill -9'd by a
 626                  * clueless admin) but has left orphan backends behind.  Check for
 627                  * this by looking to see if there is an associated shmem segment
 628                  * that is still in use.
 629                  */
 630                 if (isDDLock)
 631                 {
 632                         char       *ptr;
 633                         unsigned long id1,
 634                                                 id2;
 635
 636                         ptr = strchr(buffer, '\n');
 637                         if (ptr != NULL &&
 638                                 (ptr = strchr(ptr + 1, '\n')) != NULL)
 639                         {
 640                                 ptr++;
 641                                 if (sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
 642                                 {
 643                                         if (PGSharedMemoryIsInUse(id1, id2))
 644                                                 ereport(FATAL,
 645                                                                 (errcode(ERRCODE_LOCK_FILE_EXISTS),
 646                                                            errmsg("pre-existing shared memory block "
 647                                                                           "(key %lu, ID %lu) is still in use",
 648                                                                           id1, id2),
 649                                                            errhint("If you're sure there are no old "
 650                                                                 "server processes still running, remove "
 651                                                                            "the shared memory block with "
 652                                                                            "the command \"ipcrm\", or just delete the file \"%s\".",
 653                                                                            filename)));
 654                                 }
 655                         }
 656                 }
 657
 658                 /*
 659                  * Looks like nobody's home.  Unlink the file and try again to
 660                  * create it.  Need a loop because of possible race condition
 661                  * against other would-be creators.
 662                  */
 663                 if (unlink(filename) < 0)
 664                         ereport(FATAL,
 665                                         (errcode_for_file_access(),
 666                                          errmsg("could not remove old lock file \"%s\": %m",
 667                                                         filename),
 668                                          errhint("The file seems accidentally left over, but "
 669                                            "it could not be removed. Please remove the file "
 670                                                          "by hand and try again.")));
 671         }
 672
 673         /*
 674          * Successfully created the file, now fill it.
 675          */
 676         snprintf(buffer, sizeof(buffer), "%d\n%s\n",
 677                          amPostmaster ? (int) my_pid : -((int) my_pid),
 678                          DataDir);
 679         errno = 0;
 680         if (write(fd, buffer, strlen(buffer)) != strlen(buffer))
 681         {
 682                 int                     save_errno = errno;
 683
 684                 close(fd);
 685                 unlink(filename);
 686                 /* if write didn't set errno, assume problem is no disk space */
 687                 errno = save_errno ? save_errno : ENOSPC;
 688                 ereport(FATAL,
 689                                 (errcode_for_file_access(),
 690                           errmsg("could not write lock file \"%s\": %m", filename)));
 691         }
 692         if (close(fd))
 693         {
 694                 int                     save_errno = errno;
 695
 696                 unlink(filename);
 697                 errno = save_errno;
 698                 ereport(FATAL,
 699                                 (errcode_for_file_access(),
 700                           errmsg("could not write lock file \"%s\": %m", filename)));
 701         }
 702
 703         /*
 704          * Arrange for automatic removal of lockfile at proc_exit.
 705          */
 706         on_proc_exit(UnlinkLockFile, PointerGetDatum(strdup(filename)));
 707 }
 708
 709 void
 710 CreateDataDirLockFile(const char *datadir, bool amPostmaster)
 711 {
 712         char            lockfile[MAXPGPATH];
 713
 714         snprintf(lockfile, sizeof(lockfile), "%s/postmaster.pid", datadir);
 715         CreateLockFile(lockfile, amPostmaster, true, datadir);
 716         /* Save name of lockfile for RecordSharedMemoryInLockFile */
 717         strcpy(directoryLockFile, lockfile);
 718 }
 719
 720 void
 721 CreateSocketLockFile(const char *socketfile, bool amPostmaster)
 722 {
 723         char            lockfile[MAXPGPATH];
 724
 725         snprintf(lockfile, sizeof(lockfile), "%s.lock", socketfile);
 726         CreateLockFile(lockfile, amPostmaster, false, socketfile);
 727         /* Save name of lockfile for TouchSocketLockFile */
 728         strcpy(socketLockFile, lockfile);
 729 }
 730
 731 /*
 732  * TouchSocketLockFile -- mark socket lock file as recently accessed
 733  *
 734  * This routine should be called every so often to ensure that the lock file
 735  * has a recent mod or access date.  That saves it
 736  * from being removed by overenthusiastic /tmp-directory-cleaner daemons.
 737  * (Another reason we should never have put the socket file in /tmp...)
 738  */
 739 void
 740 TouchSocketLockFile(void)
 741 {
 742         /* Do nothing if we did not create a socket... */
 743         if (socketLockFile[0] != '\0')
 744         {
 745                 /*
 746                  * utime() is POSIX standard, utimes() is a common alternative; if
 747                  * we have neither, fall back to actually reading the file (which
 748                  * only sets the access time not mod time, but that should be
 749                  * enough in most cases).  In all paths, we ignore errors.
 750                  */
 751 #ifdef HAVE_UTIME
 752                 utime(socketLockFile, NULL);
 753 #else                                                   /* !HAVE_UTIME */
 754 #ifdef HAVE_UTIMES
 755                 utimes(socketLockFile, NULL);
 756 #else                                                   /* !HAVE_UTIMES */
 757                 int                     fd;
 758                 char            buffer[1];
 759
 760                 fd = open(socketLockFile, O_RDONLY | PG_BINARY, 0);
 761                 if (fd >= 0)
 762                 {
 763                         read(fd, buffer, sizeof(buffer));
 764                         close(fd);
 765                 }
 766 #endif   /* HAVE_UTIMES */
 767 #endif   /* HAVE_UTIME */
 768         }
 769 }
 770
 771 /*
 772  * Append information about a shared memory segment to the data directory
 773  * lock file (if we have created one).
 774  *
 775  * This may be called multiple times in the life of a postmaster, if we
 776  * delete and recreate shmem due to backend crash.      Therefore, be prepared
 777  * to overwrite existing information.  (As of 7.1, a postmaster only creates
 778  * one shm seg at a time; but for the purposes here, if we did have more than
 779  * one then any one of them would do anyway.)
 780  */
 781 void
 782 RecordSharedMemoryInLockFile(unsigned long id1, unsigned long id2)
 783 {
 784         int                     fd;
 785         int                     len;
 786         char       *ptr;
 787         char            buffer[BLCKSZ];
 788
 789         /*
 790          * Do nothing if we did not create a lockfile (probably because we are
 791          * running standalone).
 792          */
 793         if (directoryLockFile[0] == '\0')
 794                 return;
 795
 796         fd = open(directoryLockFile, O_RDWR | PG_BINARY, 0);
 797         if (fd < 0)
 798         {
 799                 ereport(LOG,
 800                                 (errcode_for_file_access(),
 801                                  errmsg("could not open file \"%s\": %m",
 802                                                 directoryLockFile)));
 803                 return;
 804         }
 805         len = read(fd, buffer, sizeof(buffer) - 100);
 806         if (len < 0)
 807         {
 808                 ereport(LOG,
 809                                 (errcode_for_file_access(),
 810                                  errmsg("could not read from file \"%s\": %m",
 811                                                 directoryLockFile)));
 812                 close(fd);
 813                 return;
 814         }
 815         buffer[len] = '\0';
 816
 817         /*
 818          * Skip over first two lines (PID and path).
 819          */
 820         ptr = strchr(buffer, '\n');
 821         if (ptr == NULL ||
 822                 (ptr = strchr(ptr + 1, '\n')) == NULL)
 823         {
 824                 elog(LOG, "bogus data in \"%s\"", directoryLockFile);
 825                 close(fd);
 826                 return;
 827         }
 828         ptr++;
 829
 830         /*
 831          * Append key information.      Format to try to keep it the same length
 832          * always (trailing junk won't hurt, but might confuse humans).
 833          */
 834         sprintf(ptr, "%9lu %9lu\n", id1, id2);
 835
 836         /*
 837          * And rewrite the data.  Since we write in a single kernel call, this
 838          * update should appear atomic to onlookers.
 839          */
 840         len = strlen(buffer);
 841         errno = 0;
 842         if (lseek(fd, (off_t) 0, SEEK_SET) != 0 ||
 843                 (int) write(fd, buffer, len) != len)
 844         {
 845                 /* if write didn't set errno, assume problem is no disk space */
 846                 if (errno == 0)
 847                         errno = ENOSPC;
 848                 ereport(LOG,
 849                                 (errcode_for_file_access(),
 850                                  errmsg("could not write to file \"%s\": %m",
 851                                                 directoryLockFile)));
 852                 close(fd);
 853                 return;
 854         }
 855         if (close(fd))
 856         {
 857                 ereport(LOG,
 858                                 (errcode_for_file_access(),
 859                                  errmsg("could not write to file \"%s\": %m",
 860                                                 directoryLockFile)));
 861         }
 862 }
 863
 864
 865 /*-------------------------------------------------------------------------
 866  *                              Version checking support
 867  *-------------------------------------------------------------------------
 868  */
 869
 870 /*
 871  * Determine whether the PG_VERSION file in directory `path' indicates
 872  * a data version compatible with the version of this program.
 873  *
 874  * If compatible, return. Otherwise, ereport(FATAL).
 875  */
 876 void
 877 ValidatePgVersion(const char *path)
 878 {
 879         char            full_path[MAXPGPATH];
 880         FILE       *file;
 881         int                     ret;
 882         long            file_major,
 883                                 file_minor;
 884         long            my_major = 0,
 885                                 my_minor = 0;
 886         char       *endptr;
 887         const char *version_string = PG_VERSION;
 888
 889         my_major = strtol(version_string, &endptr, 10);
 890         if (*endptr == '.')
 891                 my_minor = strtol(endptr + 1, NULL, 10);
 892
 893         snprintf(full_path, sizeof(full_path), "%s/PG_VERSION", path);
 894
 895         file = AllocateFile(full_path, "r");
 896         if (!file)
 897         {
 898                 if (errno == ENOENT)
 899                         ereport(FATAL,
 900                                         (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 901                                          errmsg("\"%s\" is not a valid data directory",
 902                                                         path),
 903                                          errdetail("File \"%s\" is missing.", full_path)));
 904                 else
 905                         ereport(FATAL,
 906                                         (errcode_for_file_access(),
 907                                    errmsg("could not open file \"%s\": %m", full_path)));
 908         }
 909
 910         ret = fscanf(file, "%ld.%ld", &file_major, &file_minor);
 911         if (ret != 2)
 912                 ereport(FATAL,
 913                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 914                                  errmsg("\"%s\" is not a valid data directory",
 915                                                 path),
 916                                  errdetail("File \"%s\" does not contain valid data.",
 917                                                    full_path),
 918                                  errhint("You may need to initdb.")));
 919
 920         FreeFile(file);
 921
 922         if (my_major != file_major || my_minor != file_minor)
 923                 ereport(FATAL,
 924                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 925                                  errmsg("database files are incompatible with server"),
 926                                  errdetail("The data directory was initialized by PostgreSQL version %ld.%ld, "
 927                                                  "which is not compatible with this version %s.",
 928                                                    file_major, file_minor, version_string)));
 929 }
 930
 931 /*-------------------------------------------------------------------------
 932  *                              Library preload support
 933  *-------------------------------------------------------------------------
 934  */
 935
 936 typedef void (*func_ptr) ();
 937
 938 /*
 939  * process any libraries that should be preloaded and
 940  * optionally pre-initialized
 941  */
 942 void
 943 process_preload_libraries(char *preload_libraries_string)
 944 {
 945         char       *rawstring;
 946         List       *elemlist;
 947         ListCell   *l;
 948
 949         if (preload_libraries_string == NULL)
 950                 return;
 951
 952         /* Need a modifiable copy of string */
 953         rawstring = pstrdup(preload_libraries_string);
 954
 955         /* Parse string into list of identifiers */
 956         if (!SplitIdentifierString(rawstring, ',', &elemlist))
 957         {
 958                 /* syntax error in list */
 959                 pfree(rawstring);
 960                 list_free(elemlist);
 961                 ereport(LOG,
 962                                 (errcode(ERRCODE_SYNTAX_ERROR),
 963                                  errmsg("invalid list syntax for parameter \"preload_libraries\"")));
 964                 return;
 965         }
 966
 967         foreach(l, elemlist)
 968         {
 969                 char       *tok = (char *) lfirst(l);
 970                 char       *sep = strstr(tok, ":");
 971                 char       *filename = NULL;
 972                 char       *funcname = NULL;
 973                 func_ptr        initfunc;
 974
 975                 if (sep)
 976                 {
 977                         /*
 978                          * a colon separator implies there is an initialization
 979                          * function that we need to run in addition to loading the
 980                          * library
 981                          */
 982                         size_t          filename_len = sep - tok;
 983                         size_t          funcname_len = strlen(tok) - filename_len - 1;
 984
 985                         filename = (char *) palloc(filename_len + 1);
 986                         memcpy(filename, tok, filename_len);
 987                         filename[filename_len] = '\0';
 988
 989                         funcname = (char *) palloc(funcname_len + 1);
 990                         strcpy(funcname, sep + 1);
 991                 }
 992                 else
 993                 {
 994                         /*
 995                          * no separator -- just load the library
 996                          */
 997                         filename = pstrdup(tok);
 998                         funcname = NULL;
 999                 }
1000
1001                 canonicalize_path(filename);
1002                 initfunc = (func_ptr) load_external_function(filename, funcname,
1003                                                                                                          true, NULL);
1004                 if (initfunc)
1005                         (*initfunc) ();
1006
1007                 if (funcname)
1008                         ereport(LOG,
1009                                         (errmsg("preloaded library \"%s\" with initialization function \"%s\"",
1010                                                         filename, funcname)));
1011                 else
1012                         ereport(LOG,
1013                                         (errmsg("preloaded library \"%s\"",
1014                                                         filename)));
1015
1016                 pfree(filename);
1017                 if (funcname)
1018                         pfree(funcname);
1019         }
1020
1021         pfree(rawstring);
1022         list_free(elemlist);
1023 }