1/*-------------------------------------------------------------------------
2 *
3 * postinit.c
4 * postgres initialization utilities
5 *
6 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/utils/init/postinit.c
12 *
13 *
14 *-------------------------------------------------------------------------
15 */
16#include "postgres.h"
17
18#include <ctype.h>
19#include <fcntl.h>
20#include <unistd.h>
21
22#include "access/genam.h"
23#include "access/heapam.h"
24#include "access/htup_details.h"
25#include "access/session.h"
26#include "access/sysattr.h"
27#include "access/tableam.h"
28#include "access/xact.h"
29#include "access/xlog.h"
30#include "catalog/catalog.h"
31#include "catalog/indexing.h"
32#include "catalog/namespace.h"
33#include "catalog/pg_authid.h"
34#include "catalog/pg_database.h"
35#include "catalog/pg_db_role_setting.h"
36#include "catalog/pg_tablespace.h"
37#include "libpq/auth.h"
38#include "libpq/libpq-be.h"
39#include "mb/pg_wchar.h"
40#include "miscadmin.h"
41#include "pgstat.h"
42#include "postmaster/autovacuum.h"
43#include "postmaster/postmaster.h"
44#include "replication/walsender.h"
45#include "storage/bufmgr.h"
46#include "storage/fd.h"
47#include "storage/ipc.h"
48#include "storage/lmgr.h"
49#include "storage/procarray.h"
50#include "storage/procsignal.h"
51#include "storage/proc.h"
52#include "storage/sinvaladt.h"
53#include "storage/smgr.h"
54#include "storage/sync.h"
55#include "tcop/tcopprot.h"
56#include "utils/acl.h"
57#include "utils/fmgroids.h"
58#include "utils/guc.h"
59#include "utils/memutils.h"
60#include "utils/pg_locale.h"
61#include "utils/portal.h"
62#include "utils/ps_status.h"
63#include "utils/snapmgr.h"
64#include "utils/syscache.h"
65#include "utils/timeout.h"
66
67
68static HeapTuple GetDatabaseTuple(const char *dbname);
69static HeapTuple GetDatabaseTupleByOid(Oid dboid);
70static void PerformAuthentication(Port *port);
71static void CheckMyDatabase(const char *name, bool am_superuser, bool override_allow_connections);
72static void InitCommunication(void);
73static void ShutdownPostgres(int code, Datum arg);
74static void StatementTimeoutHandler(void);
75static void LockTimeoutHandler(void);
76static void IdleInTransactionSessionTimeoutHandler(void);
77static bool ThereIsAtLeastOneRole(void);
78static void process_startup_options(Port *port, bool am_superuser);
79static void process_settings(Oid databaseid, Oid roleid);
80
81
82/*** InitPostgres support ***/
83
84
85/*
86 * GetDatabaseTuple -- fetch the pg_database row for a database
87 *
88 * This is used during backend startup when we don't yet have any access to
89 * system catalogs in general. In the worst case, we can seqscan pg_database
90 * using nothing but the hard-wired descriptor that relcache.c creates for
91 * pg_database. In more typical cases, relcache.c was able to load
92 * descriptors for both pg_database and its indexes from the shared relcache
93 * cache file, and so we can do an indexscan. criticalSharedRelcachesBuilt
94 * tells whether we got the cached descriptors.
95 */
96static HeapTuple
97GetDatabaseTuple(const char *dbname)
98{
99 HeapTuple tuple;
100 Relation relation;
101 SysScanDesc scan;
102 ScanKeyData key[1];
103
104 /*
105 * form a scan key
106 */
107 ScanKeyInit(&key[0],
108 Anum_pg_database_datname,
109 BTEqualStrategyNumber, F_NAMEEQ,
110 CStringGetDatum(dbname));
111
112 /*
113 * Open pg_database and fetch a tuple. Force heap scan if we haven't yet
114 * built the critical shared relcache entries (i.e., we're starting up
115 * without a shared relcache cache file).
116 */
117 relation = table_open(DatabaseRelationId, AccessShareLock);
118 scan = systable_beginscan(relation, DatabaseNameIndexId,
119 criticalSharedRelcachesBuilt,
120 NULL,
121 1, key);
122
123 tuple = systable_getnext(scan);
124
125 /* Must copy tuple before releasing buffer */
126 if (HeapTupleIsValid(tuple))
127 tuple = heap_copytuple(tuple);
128
129 /* all done */
130 systable_endscan(scan);
131 table_close(relation, AccessShareLock);
132
133 return tuple;
134}
135
136/*
137 * GetDatabaseTupleByOid -- as above, but search by database OID
138 */
139static HeapTuple
140GetDatabaseTupleByOid(Oid dboid)
141{
142 HeapTuple tuple;
143 Relation relation;
144 SysScanDesc scan;
145 ScanKeyData key[1];
146
147 /*
148 * form a scan key
149 */
150 ScanKeyInit(&key[0],
151 Anum_pg_database_oid,
152 BTEqualStrategyNumber, F_OIDEQ,
153 ObjectIdGetDatum(dboid));
154
155 /*
156 * Open pg_database and fetch a tuple. Force heap scan if we haven't yet
157 * built the critical shared relcache entries (i.e., we're starting up
158 * without a shared relcache cache file).
159 */
160 relation = table_open(DatabaseRelationId, AccessShareLock);
161 scan = systable_beginscan(relation, DatabaseOidIndexId,
162 criticalSharedRelcachesBuilt,
163 NULL,
164 1, key);
165
166 tuple = systable_getnext(scan);
167
168 /* Must copy tuple before releasing buffer */
169 if (HeapTupleIsValid(tuple))
170 tuple = heap_copytuple(tuple);
171
172 /* all done */
173 systable_endscan(scan);
174 table_close(relation, AccessShareLock);
175
176 return tuple;
177}
178
179
180/*
181 * PerformAuthentication -- authenticate a remote client
182 *
183 * returns: nothing. Will not return at all if there's any failure.
184 */
185static void
186PerformAuthentication(Port *port)
187{
188 /* This should be set already, but let's make sure */
189 ClientAuthInProgress = true; /* limit visibility of log messages */
190
191 /*
192 * In EXEC_BACKEND case, we didn't inherit the contents of pg_hba.conf
193 * etcetera from the postmaster, and have to load them ourselves.
194 *
195 * FIXME: [fork/exec] Ugh. Is there a way around this overhead?
196 */
197#ifdef EXEC_BACKEND
198
199 /*
200 * load_hba() and load_ident() want to work within the PostmasterContext,
201 * so create that if it doesn't exist (which it won't). We'll delete it
202 * again later, in PostgresMain.
203 */
204 if (PostmasterContext == NULL)
205 PostmasterContext = AllocSetContextCreate(TopMemoryContext,
206 "Postmaster",
207 ALLOCSET_DEFAULT_SIZES);
208
209 if (!load_hba())
210 {
211 /*
212 * It makes no sense to continue if we fail to load the HBA file,
213 * since there is no way to connect to the database in this case.
214 */
215 ereport(FATAL,
216 (errmsg("could not load pg_hba.conf")));
217 }
218
219 if (!load_ident())
220 {
221 /*
222 * It is ok to continue if we fail to load the IDENT file, although it
223 * means that you cannot log in using any of the authentication
224 * methods that need a user name mapping. load_ident() already logged
225 * the details of error to the log.
226 */
227 }
228#endif
229
230 /*
231 * Set up a timeout in case a buggy or malicious client fails to respond
232 * during authentication. Since we're inside a transaction and might do
233 * database access, we have to use the statement_timeout infrastructure.
234 */
235 enable_timeout_after(STATEMENT_TIMEOUT, AuthenticationTimeout * 1000);
236
237 /*
238 * Now perform authentication exchange.
239 */
240 ClientAuthentication(port); /* might not return, if failure */
241
242 /*
243 * Done with authentication. Disable the timeout, and log if needed.
244 */
245 disable_timeout(STATEMENT_TIMEOUT, false);
246
247 if (Log_connections)
248 {
249 if (am_walsender)
250 {
251#ifdef USE_SSL
252 if (port->ssl_in_use)
253 ereport(LOG,
254 (port->application_name != NULL
255 ? errmsg("replication connection authorized: user=%s application_name=%s SSL enabled (protocol=%s, cipher=%s, bits=%d, compression=%s)",
256 port->user_name,
257 port->application_name,
258 be_tls_get_version(port),
259 be_tls_get_cipher(port),
260 be_tls_get_cipher_bits(port),
261 be_tls_get_compression(port) ? _("on") : _("off"))
262 : errmsg("replication connection authorized: user=%s SSL enabled (protocol=%s, cipher=%s, bits=%d, compression=%s)",
263 port->user_name,
264 be_tls_get_version(port),
265 be_tls_get_cipher(port),
266 be_tls_get_cipher_bits(port),
267 be_tls_get_compression(port) ? _("on") : _("off"))));
268 else
269#endif
270 ereport(LOG,
271 (port->application_name != NULL
272 ? errmsg("replication connection authorized: user=%s application_name=%s",
273 port->user_name,
274 port->application_name)
275 : errmsg("replication connection authorized: user=%s",
276 port->user_name)));
277 }
278 else
279 {
280#ifdef USE_SSL
281 if (port->ssl_in_use)
282 ereport(LOG,
283 (port->application_name != NULL
284 ? errmsg("connection authorized: user=%s database=%s application_name=%s SSL enabled (protocol=%s, cipher=%s, bits=%d, compression=%s)",
285 port->user_name, port->database_name, port->application_name,
286 be_tls_get_version(port),
287 be_tls_get_cipher(port),
288 be_tls_get_cipher_bits(port),
289 be_tls_get_compression(port) ? _("on") : _("off"))
290 : errmsg("connection authorized: user=%s database=%s SSL enabled (protocol=%s, cipher=%s, bits=%d, compression=%s)",
291 port->user_name, port->database_name,
292 be_tls_get_version(port),
293 be_tls_get_cipher(port),
294 be_tls_get_cipher_bits(port),
295 be_tls_get_compression(port) ? _("on") : _("off"))));
296 else
297#endif
298 ereport(LOG,
299 (port->application_name != NULL
300 ? errmsg("connection authorized: user=%s database=%s application_name=%s",
301 port->user_name, port->database_name, port->application_name)
302 : errmsg("connection authorized: user=%s database=%s",
303 port->user_name, port->database_name)));
304 }
305 }
306
307 set_ps_display("startup", false);
308
309 ClientAuthInProgress = false; /* client_min_messages is active now */
310}
311
312
313/*
314 * CheckMyDatabase -- fetch information from the pg_database entry for our DB
315 */
316static void
317CheckMyDatabase(const char *name, bool am_superuser, bool override_allow_connections)
318{
319 HeapTuple tup;
320 Form_pg_database dbform;
321 char *collate;
322 char *ctype;
323
324 /* Fetch our pg_database row normally, via syscache */
325 tup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
326 if (!HeapTupleIsValid(tup))
327 elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
328 dbform = (Form_pg_database) GETSTRUCT(tup);
329
330 /* This recheck is strictly paranoia */
331 if (strcmp(name, NameStr(dbform->datname)) != 0)
332 ereport(FATAL,
333 (errcode(ERRCODE_UNDEFINED_DATABASE),
334 errmsg("database \"%s\" has disappeared from pg_database",
335 name),
336 errdetail("Database OID %u now seems to belong to \"%s\".",
337 MyDatabaseId, NameStr(dbform->datname))));
338
339 /*
340 * Check permissions to connect to the database.
341 *
342 * These checks are not enforced when in standalone mode, so that there is
343 * a way to recover from disabling all access to all databases, for
344 * example "UPDATE pg_database SET datallowconn = false;".
345 *
346 * We do not enforce them for autovacuum worker processes either.
347 */
348 if (IsUnderPostmaster && !IsAutoVacuumWorkerProcess())
349 {
350 /*
351 * Check that the database is currently allowing connections.
352 */
353 if (!dbform->datallowconn && !override_allow_connections)
354 ereport(FATAL,
355 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
356 errmsg("database \"%s\" is not currently accepting connections",
357 name)));
358
359 /*
360 * Check privilege to connect to the database. (The am_superuser test
361 * is redundant, but since we have the flag, might as well check it
362 * and save a few cycles.)
363 */
364 if (!am_superuser &&
365 pg_database_aclcheck(MyDatabaseId, GetUserId(),
366 ACL_CONNECT) != ACLCHECK_OK)
367 ereport(FATAL,
368 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
369 errmsg("permission denied for database \"%s\"", name),
370 errdetail("User does not have CONNECT privilege.")));
371
372 /*
373 * Check connection limit for this database.
374 *
375 * There is a race condition here --- we create our PGPROC before
376 * checking for other PGPROCs. If two backends did this at about the
377 * same time, they might both think they were over the limit, while
378 * ideally one should succeed and one fail. Getting that to work
379 * exactly seems more trouble than it is worth, however; instead we
380 * just document that the connection limit is approximate.
381 */
382 if (dbform->datconnlimit >= 0 &&
383 !am_superuser &&
384 CountDBConnections(MyDatabaseId) > dbform->datconnlimit)
385 ereport(FATAL,
386 (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
387 errmsg("too many connections for database \"%s\"",
388 name)));
389 }
390
391 /*
392 * OK, we're golden. Next to-do item is to save the encoding info out of
393 * the pg_database tuple.
394 */
395 SetDatabaseEncoding(dbform->encoding);
396 /* Record it as a GUC internal option, too */
397 SetConfigOption("server_encoding", GetDatabaseEncodingName(),
398 PGC_INTERNAL, PGC_S_OVERRIDE);
399 /* If we have no other source of client_encoding, use server encoding */
400 SetConfigOption("client_encoding", GetDatabaseEncodingName(),
401 PGC_BACKEND, PGC_S_DYNAMIC_DEFAULT);
402
403 /* assign locale variables */
404 collate = NameStr(dbform->datcollate);
405 ctype = NameStr(dbform->datctype);
406
407 if (pg_perm_setlocale(LC_COLLATE, collate) == NULL)
408 ereport(FATAL,
409 (errmsg("database locale is incompatible with operating system"),
410 errdetail("The database was initialized with LC_COLLATE \"%s\", "
411 " which is not recognized by setlocale().", collate),
412 errhint("Recreate the database with another locale or install the missing locale.")));
413
414 if (pg_perm_setlocale(LC_CTYPE, ctype) == NULL)
415 ereport(FATAL,
416 (errmsg("database locale is incompatible with operating system"),
417 errdetail("The database was initialized with LC_CTYPE \"%s\", "
418 " which is not recognized by setlocale().", ctype),
419 errhint("Recreate the database with another locale or install the missing locale.")));
420
421 /* Make the locale settings visible as GUC variables, too */
422 SetConfigOption("lc_collate", collate, PGC_INTERNAL, PGC_S_OVERRIDE);
423 SetConfigOption("lc_ctype", ctype, PGC_INTERNAL, PGC_S_OVERRIDE);
424
425 check_strxfrm_bug();
426
427 ReleaseSysCache(tup);
428}
429
430
431
432/* --------------------------------
433 * InitCommunication
434 *
435 * This routine initializes stuff needed for ipc, locking, etc.
436 * it should be called something more informative.
437 * --------------------------------
438 */
439static void
440InitCommunication(void)
441{
442 /*
443 * initialize shared memory and semaphores appropriately.
444 */
445 if (!IsUnderPostmaster) /* postmaster already did this */
446 {
447 /*
448 * We're running a postgres bootstrap process or a standalone backend.
449 * Though we won't listen on PostPortNumber, use it to select a shmem
450 * key. This increases the chance of detecting a leftover live
451 * backend of this DataDir.
452 */
453 CreateSharedMemoryAndSemaphores(PostPortNumber);
454 }
455}
456
457
458/*
459 * pg_split_opts -- split a string of options and append it to an argv array
460 *
461 * The caller is responsible for ensuring the argv array is large enough. The
462 * maximum possible number of arguments added by this routine is
463 * (strlen(optstr) + 1) / 2.
464 *
465 * Because some option values can contain spaces we allow escaping using
466 * backslashes, with \\ representing a literal backslash.
467 */
468void
469pg_split_opts(char **argv, int *argcp, const char *optstr)
470{
471 StringInfoData s;
472
473 initStringInfo(&s);
474
475 while (*optstr)
476 {
477 bool last_was_escape = false;
478
479 resetStringInfo(&s);
480
481 /* skip over leading space */
482 while (isspace((unsigned char) *optstr))
483 optstr++;
484
485 if (*optstr == '\0')
486 break;
487
488 /*
489 * Parse a single option, stopping at the first space, unless it's
490 * escaped.
491 */
492 while (*optstr)
493 {
494 if (isspace((unsigned char) *optstr) && !last_was_escape)
495 break;
496
497 if (!last_was_escape && *optstr == '\\')
498 last_was_escape = true;
499 else
500 {
501 last_was_escape = false;
502 appendStringInfoChar(&s, *optstr);
503 }
504
505 optstr++;
506 }
507
508 /* now store the option in the next argv[] position */
509 argv[(*argcp)++] = pstrdup(s.data);
510 }
511
512 pfree(s.data);
513}
514
515/*
516 * Initialize MaxBackends value from config options.
517 *
518 * This must be called after modules have had the chance to register background
519 * workers in shared_preload_libraries, and before shared memory size is
520 * determined.
521 *
522 * Note that in EXEC_BACKEND environment, the value is passed down from
523 * postmaster to subprocesses via BackendParameters in SubPostmasterMain; only
524 * postmaster itself and processes not under postmaster control should call
525 * this.
526 */
527void
528InitializeMaxBackends(void)
529{
530 Assert(MaxBackends == 0);
531
532 /* the extra unit accounts for the autovacuum launcher */
533 MaxBackends = MaxConnections + autovacuum_max_workers + 1 +
534 max_worker_processes + max_wal_senders;
535
536 /* internal error because the values were all checked previously */
537 if (MaxBackends > MAX_BACKENDS)
538 elog(ERROR, "too many backends configured");
539}
540
541/*
542 * Early initialization of a backend (either standalone or under postmaster).
543 * This happens even before InitPostgres.
544 *
545 * This is separate from InitPostgres because it is also called by auxiliary
546 * processes, such as the background writer process, which may not call
547 * InitPostgres at all.
548 */
549void
550BaseInit(void)
551{
552 /*
553 * Attach to shared memory and semaphores, and initialize our
554 * input/output/debugging file descriptors.
555 */
556 InitCommunication();
557 DebugFileOpen();
558
559 /* Do local initialization of file, storage and buffer managers */
560 InitFileAccess();
561 InitSync();
562 smgrinit();
563 InitBufferPoolAccess();
564}
565
566
567/* --------------------------------
568 * InitPostgres
569 * Initialize POSTGRES.
570 *
571 * The database can be specified by name, using the in_dbname parameter, or by
572 * OID, using the dboid parameter. In the latter case, the actual database
573 * name can be returned to the caller in out_dbname. If out_dbname isn't
574 * NULL, it must point to a buffer of size NAMEDATALEN.
575 *
576 * Similarly, the username can be passed by name, using the username parameter,
577 * or by OID using the useroid parameter.
578 *
579 * In bootstrap mode no parameters are used. The autovacuum launcher process
580 * doesn't use any parameters either, because it only goes far enough to be
581 * able to read pg_database; it doesn't connect to any particular database.
582 * In walsender mode only username is used.
583 *
584 * As of PostgreSQL 8.2, we expect InitProcess() was already called, so we
585 * already have a PGPROC struct ... but it's not completely filled in yet.
586 *
587 * Note:
588 * Be very careful with the order of calls in the InitPostgres function.
589 * --------------------------------
590 */
591void
592InitPostgres(const char *in_dbname, Oid dboid, const char *username,
593 Oid useroid, char *out_dbname, bool override_allow_connections)
594{
595 bool bootstrap = IsBootstrapProcessingMode();
596 bool am_superuser;
597 char *fullpath;
598 char dbname[NAMEDATALEN];
599
600 elog(DEBUG3, "InitPostgres");
601
602 /*
603 * Add my PGPROC struct to the ProcArray.
604 *
605 * Once I have done this, I am visible to other backends!
606 */
607 InitProcessPhase2();
608
609 /*
610 * Initialize my entry in the shared-invalidation manager's array of
611 * per-backend data.
612 *
613 * Sets up MyBackendId, a unique backend identifier.
614 */
615 MyBackendId = InvalidBackendId;
616
617 SharedInvalBackendInit(false);
618
619 if (MyBackendId > MaxBackends || MyBackendId <= 0)
620 elog(FATAL, "bad backend ID: %d", MyBackendId);
621
622 /* Now that we have a BackendId, we can participate in ProcSignal */
623 ProcSignalInit(MyBackendId);
624
625 /*
626 * Also set up timeout handlers needed for backend operation. We need
627 * these in every case except bootstrap.
628 */
629 if (!bootstrap)
630 {
631 RegisterTimeout(DEADLOCK_TIMEOUT, CheckDeadLockAlert);
632 RegisterTimeout(STATEMENT_TIMEOUT, StatementTimeoutHandler);
633 RegisterTimeout(LOCK_TIMEOUT, LockTimeoutHandler);
634 RegisterTimeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
635 IdleInTransactionSessionTimeoutHandler);
636 }
637
638 /*
639 * bufmgr needs another initialization call too
640 */
641 InitBufferPoolBackend();
642
643 /*
644 * Initialize local process's access to XLOG.
645 */
646 if (IsUnderPostmaster)
647 {
648 /*
649 * The postmaster already started the XLOG machinery, but we need to
650 * call InitXLOGAccess(), if the system isn't in hot-standby mode.
651 * This is handled by calling RecoveryInProgress and ignoring the
652 * result.
653 */
654 (void) RecoveryInProgress();
655 }
656 else
657 {
658 /*
659 * We are either a bootstrap process or a standalone backend. Either
660 * way, start up the XLOG machinery, and register to have it closed
661 * down at exit.
662 *
663 * We don't yet have an aux-process resource owner, but StartupXLOG
664 * and ShutdownXLOG will need one. Hence, create said resource owner
665 * (and register a callback to clean it up after ShutdownXLOG runs).
666 */
667 CreateAuxProcessResourceOwner();
668
669 StartupXLOG();
670 /* Release (and warn about) any buffer pins leaked in StartupXLOG */
671 ReleaseAuxProcessResources(true);
672 /* Reset CurrentResourceOwner to nothing for the moment */
673 CurrentResourceOwner = NULL;
674
675 on_shmem_exit(ShutdownXLOG, 0);
676 }
677
678 /*
679 * Initialize the relation cache and the system catalog caches. Note that
680 * no catalog access happens here; we only set up the hashtable structure.
681 * We must do this before starting a transaction because transaction abort
682 * would try to touch these hashtables.
683 */
684 RelationCacheInitialize();
685 InitCatalogCache();
686 InitPlanCache();
687
688 /* Initialize portal manager */
689 EnablePortalManager();
690
691 /* Initialize stats collection --- must happen before first xact */
692 if (!bootstrap)
693 pgstat_initialize();
694
695 /*
696 * Load relcache entries for the shared system catalogs. This must create
697 * at least entries for pg_database and catalogs used for authentication.
698 */
699 RelationCacheInitializePhase2();
700
701 /*
702 * Set up process-exit callback to do pre-shutdown cleanup. This is the
703 * first before_shmem_exit callback we register; thus, this will be the
704 * last thing we do before low-level modules like the buffer manager begin
705 * to close down. We need to have this in place before we begin our first
706 * transaction --- if we fail during the initialization transaction, as is
707 * entirely possible, we need the AbortTransaction call to clean up.
708 */
709 before_shmem_exit(ShutdownPostgres, 0);
710
711 /* The autovacuum launcher is done here */
712 if (IsAutoVacuumLauncherProcess())
713 {
714 /* report this backend in the PgBackendStatus array */
715 pgstat_bestart();
716
717 return;
718 }
719
720 /*
721 * Start a new transaction here before first access to db, and get a
722 * snapshot. We don't have a use for the snapshot itself, but we're
723 * interested in the secondary effect that it sets RecentGlobalXmin. (This
724 * is critical for anything that reads heap pages, because HOT may decide
725 * to prune them even if the process doesn't attempt to modify any
726 * tuples.)
727 */
728 if (!bootstrap)
729 {
730 /* statement_timestamp must be set for timeouts to work correctly */
731 SetCurrentStatementStartTimestamp();
732 StartTransactionCommand();
733
734 /*
735 * transaction_isolation will have been set to the default by the
736 * above. If the default is "serializable", and we are in hot
737 * standby, we will fail if we don't change it to something lower.
738 * Fortunately, "read committed" is plenty good enough.
739 */
740 XactIsoLevel = XACT_READ_COMMITTED;
741
742 (void) GetTransactionSnapshot();
743 }
744
745 /*
746 * Perform client authentication if necessary, then figure out our
747 * postgres user ID, and see if we are a superuser.
748 *
749 * In standalone mode and in autovacuum worker processes, we use a fixed
750 * ID, otherwise we figure it out from the authenticated user name.
751 */
752 if (bootstrap || IsAutoVacuumWorkerProcess())
753 {
754 InitializeSessionUserIdStandalone();
755 am_superuser = true;
756 }
757 else if (!IsUnderPostmaster)
758 {
759 InitializeSessionUserIdStandalone();
760 am_superuser = true;
761 if (!ThereIsAtLeastOneRole())
762 ereport(WARNING,
763 (errcode(ERRCODE_UNDEFINED_OBJECT),
764 errmsg("no roles are defined in this database system"),
765 errhint("You should immediately run CREATE USER \"%s\" SUPERUSER;.",
766 username != NULL ? username : "postgres")));
767 }
768 else if (IsBackgroundWorker)
769 {
770 if (username == NULL && !OidIsValid(useroid))
771 {
772 InitializeSessionUserIdStandalone();
773 am_superuser = true;
774 }
775 else
776 {
777 InitializeSessionUserId(username, useroid);
778 am_superuser = superuser();
779 }
780 }
781 else
782 {
783 /* normal multiuser case */
784 Assert(MyProcPort != NULL);
785 PerformAuthentication(MyProcPort);
786 InitializeSessionUserId(username, useroid);
787 am_superuser = superuser();
788 }
789
790 /*
791 * If we're trying to shut down, only superusers can connect, and new
792 * replication connections are not allowed.
793 */
794 if ((!am_superuser || am_walsender) &&
795 MyProcPort != NULL &&
796 MyProcPort->canAcceptConnections == CAC_WAITBACKUP)
797 {
798 if (am_walsender)
799 ereport(FATAL,
800 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
801 errmsg("new replication connections are not allowed during database shutdown")));
802 else
803 ereport(FATAL,
804 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
805 errmsg("must be superuser to connect during database shutdown")));
806 }
807
808 /*
809 * Binary upgrades only allowed super-user connections
810 */
811 if (IsBinaryUpgrade && !am_superuser)
812 {
813 ereport(FATAL,
814 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
815 errmsg("must be superuser to connect in binary upgrade mode")));
816 }
817
818 /*
819 * The last few connection slots are reserved for superusers. Replication
820 * connections are drawn from slots reserved with max_wal_senders and not
821 * limited by max_connections or superuser_reserved_connections.
822 */
823 if (!am_superuser && !am_walsender &&
824 ReservedBackends > 0 &&
825 !HaveNFreeProcs(ReservedBackends))
826 ereport(FATAL,
827 (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
828 errmsg("remaining connection slots are reserved for non-replication superuser connections")));
829
830 /* Check replication permissions needed for walsender processes. */
831 if (am_walsender)
832 {
833 Assert(!bootstrap);
834
835 if (!superuser() && !has_rolreplication(GetUserId()))
836 ereport(FATAL,
837 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
838 errmsg("must be superuser or replication role to start walsender")));
839 }
840
841 /*
842 * If this is a plain walsender only supporting physical replication, we
843 * don't want to connect to any particular database. Just finish the
844 * backend startup by processing any options from the startup packet, and
845 * we're done.
846 */
847 if (am_walsender && !am_db_walsender)
848 {
849 /* process any options passed in the startup packet */
850 if (MyProcPort != NULL)
851 process_startup_options(MyProcPort, am_superuser);
852
853 /* Apply PostAuthDelay as soon as we've read all options */
854 if (PostAuthDelay > 0)
855 pg_usleep(PostAuthDelay * 1000000L);
856
857 /* initialize client encoding */
858 InitializeClientEncoding();
859
860 /* report this backend in the PgBackendStatus array */
861 pgstat_bestart();
862
863 /* close the transaction we started above */
864 CommitTransactionCommand();
865
866 return;
867 }
868
869 /*
870 * Set up the global variables holding database id and default tablespace.
871 * But note we won't actually try to touch the database just yet.
872 *
873 * We take a shortcut in the bootstrap case, otherwise we have to look up
874 * the db's entry in pg_database.
875 */
876 if (bootstrap)
877 {
878 MyDatabaseId = TemplateDbOid;
879 MyDatabaseTableSpace = DEFAULTTABLESPACE_OID;
880 }
881 else if (in_dbname != NULL)
882 {
883 HeapTuple tuple;
884 Form_pg_database dbform;
885
886 tuple = GetDatabaseTuple(in_dbname);
887 if (!HeapTupleIsValid(tuple))
888 ereport(FATAL,
889 (errcode(ERRCODE_UNDEFINED_DATABASE),
890 errmsg("database \"%s\" does not exist", in_dbname)));
891 dbform = (Form_pg_database) GETSTRUCT(tuple);
892 MyDatabaseId = dbform->oid;
893 MyDatabaseTableSpace = dbform->dattablespace;
894 /* take database name from the caller, just for paranoia */
895 strlcpy(dbname, in_dbname, sizeof(dbname));
896 }
897 else if (OidIsValid(dboid))
898 {
899 /* caller specified database by OID */
900 HeapTuple tuple;
901 Form_pg_database dbform;
902
903 tuple = GetDatabaseTupleByOid(dboid);
904 if (!HeapTupleIsValid(tuple))
905 ereport(FATAL,
906 (errcode(ERRCODE_UNDEFINED_DATABASE),
907 errmsg("database %u does not exist", dboid)));
908 dbform = (Form_pg_database) GETSTRUCT(tuple);
909 MyDatabaseId = dbform->oid;
910 MyDatabaseTableSpace = dbform->dattablespace;
911 Assert(MyDatabaseId == dboid);
912 strlcpy(dbname, NameStr(dbform->datname), sizeof(dbname));
913 /* pass the database name back to the caller */
914 if (out_dbname)
915 strcpy(out_dbname, dbname);
916 }
917 else
918 {
919 /*
920 * If this is a background worker not bound to any particular
921 * database, we're done now. Everything that follows only makes sense
922 * if we are bound to a specific database. We do need to close the
923 * transaction we started before returning.
924 */
925 if (!bootstrap)
926 {
927 pgstat_bestart();
928 CommitTransactionCommand();
929 }
930 return;
931 }
932
933 /*
934 * Now, take a writer's lock on the database we are trying to connect to.
935 * If there is a concurrently running DROP DATABASE on that database, this
936 * will block us until it finishes (and has committed its update of
937 * pg_database).
938 *
939 * Note that the lock is not held long, only until the end of this startup
940 * transaction. This is OK since we will advertise our use of the
941 * database in the ProcArray before dropping the lock (in fact, that's the
942 * next thing to do). Anyone trying a DROP DATABASE after this point will
943 * see us in the array once they have the lock. Ordering is important for
944 * this because we don't want to advertise ourselves as being in this
945 * database until we have the lock; otherwise we create what amounts to a
946 * deadlock with CountOtherDBBackends().
947 *
948 * Note: use of RowExclusiveLock here is reasonable because we envision
949 * our session as being a concurrent writer of the database. If we had a
950 * way of declaring a session as being guaranteed-read-only, we could use
951 * AccessShareLock for such sessions and thereby not conflict against
952 * CREATE DATABASE.
953 */
954 if (!bootstrap)
955 LockSharedObject(DatabaseRelationId, MyDatabaseId, 0,
956 RowExclusiveLock);
957
958 /*
959 * Now we can mark our PGPROC entry with the database ID.
960 *
961 * We assume this is an atomic store so no lock is needed; though actually
962 * things would work fine even if it weren't atomic. Anyone searching the
963 * ProcArray for this database's ID should hold the database lock, so they
964 * would not be executing concurrently with this store. A process looking
965 * for another database's ID could in theory see a chance match if it read
966 * a partially-updated databaseId value; but as long as all such searches
967 * wait and retry, as in CountOtherDBBackends(), they will certainly see
968 * the correct value on their next try.
969 */
970 MyProc->databaseId = MyDatabaseId;
971
972 /*
973 * We established a catalog snapshot while reading pg_authid and/or
974 * pg_database; but until we have set up MyDatabaseId, we won't react to
975 * incoming sinval messages for unshared catalogs, so we won't realize it
976 * if the snapshot has been invalidated. Assume it's no good anymore.
977 */
978 InvalidateCatalogSnapshot();
979
980 /*
981 * Recheck pg_database to make sure the target database hasn't gone away.
982 * If there was a concurrent DROP DATABASE, this ensures we will die
983 * cleanly without creating a mess.
984 */
985 if (!bootstrap)
986 {
987 HeapTuple tuple;
988
989 tuple = GetDatabaseTuple(dbname);
990 if (!HeapTupleIsValid(tuple) ||
991 MyDatabaseId != ((Form_pg_database) GETSTRUCT(tuple))->oid ||
992 MyDatabaseTableSpace != ((Form_pg_database) GETSTRUCT(tuple))->dattablespace)
993 ereport(FATAL,
994 (errcode(ERRCODE_UNDEFINED_DATABASE),
995 errmsg("database \"%s\" does not exist", dbname),
996 errdetail("It seems to have just been dropped or renamed.")));
997 }
998
999 /*
1000 * Now we should be able to access the database directory safely. Verify
1001 * it's there and looks reasonable.
1002 */
1003 fullpath = GetDatabasePath(MyDatabaseId, MyDatabaseTableSpace);
1004
1005 if (!bootstrap)
1006 {
1007 if (access(fullpath, F_OK) == -1)
1008 {
1009 if (errno == ENOENT)
1010 ereport(FATAL,
1011 (errcode(ERRCODE_UNDEFINED_DATABASE),
1012 errmsg("database \"%s\" does not exist",
1013 dbname),
1014 errdetail("The database subdirectory \"%s\" is missing.",
1015 fullpath)));
1016 else
1017 ereport(FATAL,
1018 (errcode_for_file_access(),
1019 errmsg("could not access directory \"%s\": %m",
1020 fullpath)));
1021 }
1022
1023 ValidatePgVersion(fullpath);
1024 }
1025
1026 SetDatabasePath(fullpath);
1027
1028 /*
1029 * It's now possible to do real access to the system catalogs.
1030 *
1031 * Load relcache entries for the system catalogs. This must create at
1032 * least the minimum set of "nailed-in" cache entries.
1033 */
1034 RelationCacheInitializePhase3();
1035
1036 /* set up ACL framework (so CheckMyDatabase can check permissions) */
1037 initialize_acl();
1038
1039 /*
1040 * Re-read the pg_database row for our database, check permissions and set
1041 * up database-specific GUC settings. We can't do this until all the
1042 * database-access infrastructure is up. (Also, it wants to know if the
1043 * user is a superuser, so the above stuff has to happen first.)
1044 */
1045 if (!bootstrap)
1046 CheckMyDatabase(dbname, am_superuser, override_allow_connections);
1047
1048 /*
1049 * Now process any command-line switches and any additional GUC variable
1050 * settings passed in the startup packet. We couldn't do this before
1051 * because we didn't know if client is a superuser.
1052 */
1053 if (MyProcPort != NULL)
1054 process_startup_options(MyProcPort, am_superuser);
1055
1056 /* Process pg_db_role_setting options */
1057 process_settings(MyDatabaseId, GetSessionUserId());
1058
1059 /* Apply PostAuthDelay as soon as we've read all options */
1060 if (PostAuthDelay > 0)
1061 pg_usleep(PostAuthDelay * 1000000L);
1062
1063 /*
1064 * Initialize various default states that can't be set up until we've
1065 * selected the active user and gotten the right GUC settings.
1066 */
1067
1068 /* set default namespace search path */
1069 InitializeSearchPath();
1070
1071 /* initialize client encoding */
1072 InitializeClientEncoding();
1073
1074 /* Initialize this backend's session state. */
1075 InitializeSession();
1076
1077 /* report this backend in the PgBackendStatus array */
1078 if (!bootstrap)
1079 pgstat_bestart();
1080
1081 /* close the transaction we started above */
1082 if (!bootstrap)
1083 CommitTransactionCommand();
1084}
1085
1086/*
1087 * Process any command-line switches and any additional GUC variable
1088 * settings passed in the startup packet.
1089 */
1090static void
1091process_startup_options(Port *port, bool am_superuser)
1092{
1093 GucContext gucctx;
1094 ListCell *gucopts;
1095
1096 gucctx = am_superuser ? PGC_SU_BACKEND : PGC_BACKEND;
1097
1098 /*
1099 * First process any command-line switches that were included in the
1100 * startup packet, if we are in a regular backend.
1101 */
1102 if (port->cmdline_options != NULL)
1103 {
1104 /*
1105 * The maximum possible number of commandline arguments that could
1106 * come from port->cmdline_options is (strlen + 1) / 2; see
1107 * pg_split_opts().
1108 */
1109 char **av;
1110 int maxac;
1111 int ac;
1112
1113 maxac = 2 + (strlen(port->cmdline_options) + 1) / 2;
1114
1115 av = (char **) palloc(maxac * sizeof(char *));
1116 ac = 0;
1117
1118 av[ac++] = "postgres";
1119
1120 pg_split_opts(av, &ac, port->cmdline_options);
1121
1122 av[ac] = NULL;
1123
1124 Assert(ac < maxac);
1125
1126 (void) process_postgres_switches(ac, av, gucctx, NULL);
1127 }
1128
1129 /*
1130 * Process any additional GUC variable settings passed in startup packet.
1131 * These are handled exactly like command-line variables.
1132 */
1133 gucopts = list_head(port->guc_options);
1134 while (gucopts)
1135 {
1136 char *name;
1137 char *value;
1138
1139 name = lfirst(gucopts);
1140 gucopts = lnext(gucopts);
1141
1142 value = lfirst(gucopts);
1143 gucopts = lnext(gucopts);
1144
1145 SetConfigOption(name, value, gucctx, PGC_S_CLIENT);
1146 }
1147}
1148
1149/*
1150 * Load GUC settings from pg_db_role_setting.
1151 *
1152 * We try specific settings for the database/role combination, as well as
1153 * general for this database and for this user.
1154 */
1155static void
1156process_settings(Oid databaseid, Oid roleid)
1157{
1158 Relation relsetting;
1159 Snapshot snapshot;
1160
1161 if (!IsUnderPostmaster)
1162 return;
1163
1164 relsetting = table_open(DbRoleSettingRelationId, AccessShareLock);
1165
1166 /* read all the settings under the same snapshot for efficiency */
1167 snapshot = RegisterSnapshot(GetCatalogSnapshot(DbRoleSettingRelationId));
1168
1169 /* Later settings are ignored if set earlier. */
1170 ApplySetting(snapshot, databaseid, roleid, relsetting, PGC_S_DATABASE_USER);
1171 ApplySetting(snapshot, InvalidOid, roleid, relsetting, PGC_S_USER);
1172 ApplySetting(snapshot, databaseid, InvalidOid, relsetting, PGC_S_DATABASE);
1173 ApplySetting(snapshot, InvalidOid, InvalidOid, relsetting, PGC_S_GLOBAL);
1174
1175 UnregisterSnapshot(snapshot);
1176 table_close(relsetting, AccessShareLock);
1177}
1178
1179/*
1180 * Backend-shutdown callback. Do cleanup that we want to be sure happens
1181 * before all the supporting modules begin to nail their doors shut via
1182 * their own callbacks.
1183 *
1184 * User-level cleanup, such as temp-relation removal and UNLISTEN, happens
1185 * via separate callbacks that execute before this one. We don't combine the
1186 * callbacks because we still want this one to happen if the user-level
1187 * cleanup fails.
1188 */
1189static void
1190ShutdownPostgres(int code, Datum arg)
1191{
1192 /* Make sure we've killed any active transaction */
1193 AbortOutOfAnyTransaction();
1194
1195 /*
1196 * User locks are not released by transaction end, so be sure to release
1197 * them explicitly.
1198 */
1199 LockReleaseAll(USER_LOCKMETHOD, true);
1200}
1201
1202
1203/*
1204 * STATEMENT_TIMEOUT handler: trigger a query-cancel interrupt.
1205 */
1206static void
1207StatementTimeoutHandler(void)
1208{
1209 int sig = SIGINT;
1210
1211 /*
1212 * During authentication the timeout is used to deal with
1213 * authentication_timeout - we want to quit in response to such timeouts.
1214 */
1215 if (ClientAuthInProgress)
1216 sig = SIGTERM;
1217
1218#ifdef HAVE_SETSID
1219 /* try to signal whole process group */
1220 kill(-MyProcPid, sig);
1221#endif
1222 kill(MyProcPid, sig);
1223}
1224
1225/*
1226 * LOCK_TIMEOUT handler: trigger a query-cancel interrupt.
1227 */
1228static void
1229LockTimeoutHandler(void)
1230{
1231#ifdef HAVE_SETSID
1232 /* try to signal whole process group */
1233 kill(-MyProcPid, SIGINT);
1234#endif
1235 kill(MyProcPid, SIGINT);
1236}
1237
1238static void
1239IdleInTransactionSessionTimeoutHandler(void)
1240{
1241 IdleInTransactionSessionTimeoutPending = true;
1242 InterruptPending = true;
1243 SetLatch(MyLatch);
1244}
1245
1246/*
1247 * Returns true if at least one role is defined in this database cluster.
1248 */
1249static bool
1250ThereIsAtLeastOneRole(void)
1251{
1252 Relation pg_authid_rel;
1253 TableScanDesc scan;
1254 bool result;
1255
1256 pg_authid_rel = table_open(AuthIdRelationId, AccessShareLock);
1257
1258 scan = table_beginscan_catalog(pg_authid_rel, 0, NULL);
1259 result = (heap_getnext(scan, ForwardScanDirection) != NULL);
1260
1261 table_endscan(scan);
1262 table_close(pg_authid_rel, AccessShareLock);
1263
1264 return result;
1265}
1266