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Disallow converting a table to a view within an outer SQL command.
[pgsql.git] / src / backend / rewrite / rewriteDefine.c
blobcf6c47b5963ebff8716ada89ff6d89eb9438cad7
1 /*-------------------------------------------------------------------------
2 *
3 * rewriteDefine.c
4 * routines for defining a rewrite rule
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/rewrite/rewriteDefine.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "access/heapam.h"
18 #include "access/htup_details.h"
19 #include "access/multixact.h"
20 #include "access/tableam.h"
21 #include "access/transam.h"
22 #include "access/xact.h"
23 #include "catalog/catalog.h"
24 #include "catalog/dependency.h"
25 #include "catalog/heap.h"
26 #include "catalog/indexing.h"
27 #include "catalog/namespace.h"
28 #include "catalog/objectaccess.h"
29 #include "catalog/pg_inherits.h"
30 #include "catalog/pg_rewrite.h"
31 #include "catalog/storage.h"
32 #include "commands/policy.h"
33 #include "commands/tablecmds.h"
34 #include "miscadmin.h"
35 #include "nodes/nodeFuncs.h"
36 #include "parser/parse_utilcmd.h"
37 #include "rewrite/rewriteDefine.h"
38 #include "rewrite/rewriteManip.h"
39 #include "rewrite/rewriteSupport.h"
40 #include "utils/acl.h"
41 #include "utils/builtins.h"
42 #include "utils/inval.h"
43 #include "utils/lsyscache.h"
44 #include "utils/rel.h"
45 #include "utils/snapmgr.h"
46 #include "utils/syscache.h"
47
48
49 static void checkRuleResultList(List *targetList, TupleDesc resultDesc,
50 bool isSelect, bool requireColumnNameMatch);
51 static bool setRuleCheckAsUser_walker(Node *node, Oid *context);
52 static void setRuleCheckAsUser_Query(Query *qry, Oid userid);
53
54
55 /*
56 * InsertRule -
57 * takes the arguments and inserts them as a row into the system
58 * relation "pg_rewrite"
59 */
60 static Oid
61 InsertRule(const char *rulname,
62 int evtype,
63 Oid eventrel_oid,
64 bool evinstead,
65 Node *event_qual,
66 List *action,
67 bool replace)
68 {
69 char *evqual = nodeToString(event_qual);
70 char *actiontree = nodeToString((Node *) action);
71 Datum values[Natts_pg_rewrite];
72 bool nulls[Natts_pg_rewrite];
73 bool replaces[Natts_pg_rewrite];
74 NameData rname;
75 Relation pg_rewrite_desc;
76 HeapTuple tup,
77 oldtup;
78 Oid rewriteObjectId;
79 ObjectAddress myself,
80 referenced;
81 bool is_update = false;
82
83 /*
84 * Set up *nulls and *values arrays
85 */
86 MemSet(nulls, false, sizeof(nulls));
87
88 namestrcpy(&rname, rulname);
89 values[Anum_pg_rewrite_rulename - 1] = NameGetDatum(&rname);
90 values[Anum_pg_rewrite_ev_class - 1] = ObjectIdGetDatum(eventrel_oid);
91 values[Anum_pg_rewrite_ev_type - 1] = CharGetDatum(evtype + '0');
92 values[Anum_pg_rewrite_ev_enabled - 1] = CharGetDatum(RULE_FIRES_ON_ORIGIN);
93 values[Anum_pg_rewrite_is_instead - 1] = BoolGetDatum(evinstead);
94 values[Anum_pg_rewrite_ev_qual - 1] = CStringGetTextDatum(evqual);
95 values[Anum_pg_rewrite_ev_action - 1] = CStringGetTextDatum(actiontree);
96
97 /*
98 * Ready to store new pg_rewrite tuple
99 */
100 pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock);
101
102 /*
103 * Check to see if we are replacing an existing tuple
104 */
105 oldtup = SearchSysCache2(RULERELNAME,
106 ObjectIdGetDatum(eventrel_oid),
107 PointerGetDatum(rulname));
108
109 if (HeapTupleIsValid(oldtup))
110 {
111 if (!replace)
112 ereport(ERROR,
113 (errcode(ERRCODE_DUPLICATE_OBJECT),
114 errmsg("rule \"%s\" for relation \"%s\" already exists",
115 rulname, get_rel_name(eventrel_oid))));
116
117 /*
118 * When replacing, we don't need to replace every attribute
119 */
120 MemSet(replaces, false, sizeof(replaces));
121 replaces[Anum_pg_rewrite_ev_type - 1] = true;
122 replaces[Anum_pg_rewrite_is_instead - 1] = true;
123 replaces[Anum_pg_rewrite_ev_qual - 1] = true;
124 replaces[Anum_pg_rewrite_ev_action - 1] = true;
125
126 tup = heap_modify_tuple(oldtup, RelationGetDescr(pg_rewrite_desc),
127 values, nulls, replaces);
128
129 CatalogTupleUpdate(pg_rewrite_desc, &tup->t_self, tup);
130
131 ReleaseSysCache(oldtup);
132
133 rewriteObjectId = ((Form_pg_rewrite) GETSTRUCT(tup))->oid;
134 is_update = true;
135 }
136 else
137 {
138 rewriteObjectId = GetNewOidWithIndex(pg_rewrite_desc,
139 RewriteOidIndexId,
140 Anum_pg_rewrite_oid);
141 values[Anum_pg_rewrite_oid - 1] = ObjectIdGetDatum(rewriteObjectId);
142
143 tup = heap_form_tuple(pg_rewrite_desc->rd_att, values, nulls);
144
145 CatalogTupleInsert(pg_rewrite_desc, tup);
146 }
147
148
149 heap_freetuple(tup);
150
151 /* If replacing, get rid of old dependencies and make new ones */
152 if (is_update)
153 deleteDependencyRecordsFor(RewriteRelationId, rewriteObjectId, false);
154
155 /*
156 * Install dependency on rule's relation to ensure it will go away on
157 * relation deletion. If the rule is ON SELECT, make the dependency
158 * implicit --- this prevents deleting a view's SELECT rule. Other kinds
159 * of rules can be AUTO.
160 */
161 myself.classId = RewriteRelationId;
162 myself.objectId = rewriteObjectId;
163 myself.objectSubId = 0;
164
165 referenced.classId = RelationRelationId;
166 referenced.objectId = eventrel_oid;
167 referenced.objectSubId = 0;
168
169 recordDependencyOn(&myself, &referenced,
170 (evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
171
172 /*
173 * Also install dependencies on objects referenced in action and qual.
174 */
175 recordDependencyOnExpr(&myself, (Node *) action, NIL,
176 DEPENDENCY_NORMAL);
177
178 if (event_qual != NULL)
179 {
180 /* Find query containing OLD/NEW rtable entries */
181 Query *qry = linitial_node(Query, action);
182
183 qry = getInsertSelectQuery(qry, NULL);
184 recordDependencyOnExpr(&myself, event_qual, qry->rtable,
185 DEPENDENCY_NORMAL);
186 }
187
188 /* Post creation hook for new rule */
189 InvokeObjectPostCreateHook(RewriteRelationId, rewriteObjectId, 0);
190
191 table_close(pg_rewrite_desc, RowExclusiveLock);
192
193 return rewriteObjectId;
194 }
195
196 /*
197 * DefineRule
198 * Execute a CREATE RULE command.
199 */
200 ObjectAddress
201 DefineRule(RuleStmt *stmt, const char *queryString)
202 {
203 List *actions;
204 Node *whereClause;
205 Oid relId;
206
207 /* Parse analysis. */
208 transformRuleStmt(stmt, queryString, &actions, &whereClause);
209
210 /*
211 * Find and lock the relation. Lock level should match
212 * DefineQueryRewrite.
213 */
214 relId = RangeVarGetRelid(stmt->relation, AccessExclusiveLock, false);
215
216 /* ... and execute */
217 return DefineQueryRewrite(stmt->rulename,
218 relId,
219 whereClause,
220 stmt->event,
221 stmt->instead,
222 stmt->replace,
223 actions);
224 }
225
226
227 /*
228 * DefineQueryRewrite
229 * Create a rule
230 *
231 * This is essentially the same as DefineRule() except that the rule's
232 * action and qual have already been passed through parse analysis.
233 */
234 ObjectAddress
235 DefineQueryRewrite(const char *rulename,
236 Oid event_relid,
237 Node *event_qual,
238 CmdType event_type,
239 bool is_instead,
240 bool replace,
241 List *action)
242 {
243 Relation event_relation;
244 ListCell *l;
245 Query *query;
246 bool RelisBecomingView = false;
247 Oid ruleId = InvalidOid;
248 ObjectAddress address;
249
250 /*
251 * If we are installing an ON SELECT rule, we had better grab
252 * AccessExclusiveLock to ensure no SELECTs are currently running on the
253 * event relation. For other types of rules, it would be sufficient to
254 * grab ShareRowExclusiveLock to lock out insert/update/delete actions and
255 * to ensure that we lock out current CREATE RULE statements; but because
256 * of race conditions in access to catalog entries, we can't do that yet.
257 *
258 * Note that this lock level should match the one used in DefineRule.
259 */
260 event_relation = table_open(event_relid, AccessExclusiveLock);
261
262 /*
263 * Verify relation is of a type that rules can sensibly be applied to.
264 * Internal callers can target materialized views, but transformRuleStmt()
265 * blocks them for users. Don't mention them in the error message.
266 */
267 if (event_relation->rd_rel->relkind != RELKIND_RELATION &&
268 event_relation->rd_rel->relkind != RELKIND_MATVIEW &&
269 event_relation->rd_rel->relkind != RELKIND_VIEW &&
270 event_relation->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
271 ereport(ERROR,
272 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
273 errmsg("\"%s\" is not a table or view",
274 RelationGetRelationName(event_relation))));
275
276 if (!allowSystemTableMods && IsSystemRelation(event_relation))
277 ereport(ERROR,
278 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
279 errmsg("permission denied: \"%s\" is a system catalog",
280 RelationGetRelationName(event_relation))));
281
282 /*
283 * Check user has permission to apply rules to this relation.
284 */
285 if (!pg_class_ownercheck(event_relid, GetUserId()))
286 aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(event_relation->rd_rel->relkind),
287 RelationGetRelationName(event_relation));
288
289 /*
290 * No rule actions that modify OLD or NEW
291 */
292 foreach(l, action)
293 {
294 query = lfirst_node(Query, l);
295 if (query->resultRelation == 0)
296 continue;
297 /* Don't be fooled by INSERT/SELECT */
298 if (query != getInsertSelectQuery(query, NULL))
299 continue;
300 if (query->resultRelation == PRS2_OLD_VARNO)
301 ereport(ERROR,
302 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
303 errmsg("rule actions on OLD are not implemented"),
304 errhint("Use views or triggers instead.")));
305 if (query->resultRelation == PRS2_NEW_VARNO)
306 ereport(ERROR,
307 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
308 errmsg("rule actions on NEW are not implemented"),
309 errhint("Use triggers instead.")));
310 }
311
312 if (event_type == CMD_SELECT)
313 {
314 /*
315 * Rules ON SELECT are restricted to view definitions
316 *
317 * So there cannot be INSTEAD NOTHING, ...
318 */
319 if (list_length(action) == 0)
320 ereport(ERROR,
321 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
322 errmsg("INSTEAD NOTHING rules on SELECT are not implemented"),
323 errhint("Use views instead.")));
324
325 /*
326 * ... there cannot be multiple actions, ...
327 */
328 if (list_length(action) > 1)
329 ereport(ERROR,
330 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
331 errmsg("multiple actions for rules on SELECT are not implemented")));
332
333 /*
334 * ... the one action must be a SELECT, ...
335 */
336 query = linitial_node(Query, action);
337 if (!is_instead ||
338 query->commandType != CMD_SELECT)
339 ereport(ERROR,
340 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
341 errmsg("rules on SELECT must have action INSTEAD SELECT")));
342
343 /*
344 * ... it cannot contain data-modifying WITH ...
345 */
346 if (query->hasModifyingCTE)
347 ereport(ERROR,
348 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
349 errmsg("rules on SELECT must not contain data-modifying statements in WITH")));
350
351 /*
352 * ... there can be no rule qual, ...
353 */
354 if (event_qual != NULL)
355 ereport(ERROR,
356 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
357 errmsg("event qualifications are not implemented for rules on SELECT")));
358
359 /*
360 * ... the targetlist of the SELECT action must exactly match the
361 * event relation, ...
362 */
363 checkRuleResultList(query->targetList,
364 RelationGetDescr(event_relation),
365 true,
366 event_relation->rd_rel->relkind !=
367 RELKIND_MATVIEW);
368
369 /*
370 * ... there must not be another ON SELECT rule already ...
371 */
372 if (!replace && event_relation->rd_rules != NULL)
373 {
374 int i;
375
376 for (i = 0; i < event_relation->rd_rules->numLocks; i++)
377 {
378 RewriteRule *rule;
379
380 rule = event_relation->rd_rules->rules[i];
381 if (rule->event == CMD_SELECT)
382 ereport(ERROR,
383 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
384 errmsg("\"%s\" is already a view",
385 RelationGetRelationName(event_relation))));
386 }
387 }
388
389 /*
390 * ... and finally the rule must be named _RETURN.
391 */
392 if (strcmp(rulename, ViewSelectRuleName) != 0)
393 {
394 /*
395 * In versions before 7.3, the expected name was _RETviewname. For
396 * backwards compatibility with old pg_dump output, accept that
397 * and silently change it to _RETURN. Since this is just a quick
398 * backwards-compatibility hack, limit the number of characters
399 * checked to a few less than NAMEDATALEN; this saves having to
400 * worry about where a multibyte character might have gotten
401 * truncated.
402 */
403 if (strncmp(rulename, "_RET", 4) != 0 ||
404 strncmp(rulename + 4, RelationGetRelationName(event_relation),
405 NAMEDATALEN - 4 - 4) != 0)
406 ereport(ERROR,
407 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
408 errmsg("view rule for \"%s\" must be named \"%s\"",
409 RelationGetRelationName(event_relation),
410 ViewSelectRuleName)));
411 rulename = pstrdup(ViewSelectRuleName);
412 }
413
414 /*
415 * Are we converting a relation to a view?
416 *
417 * If so, check that the relation is empty because the storage for the
418 * relation is going to be deleted. Also insist that the rel not be
419 * involved in partitioning, nor have any triggers, indexes, child or
420 * parent tables, RLS policies, or RLS enabled. (Note: some of these
421 * tests are too strict, because they will reject relations that once
422 * had such but don't anymore. But we don't really care, because this
423 * whole business of converting relations to views is just an obsolete
424 * kluge to allow dump/reload of views that participate in circular
425 * dependencies.)
426 *
427 * Also ensure the relation isn't being manipulated in any outer SQL
428 * command of our own session.
429 */
430 if (event_relation->rd_rel->relkind != RELKIND_VIEW &&
431 event_relation->rd_rel->relkind != RELKIND_MATVIEW)
432 {
433 TableScanDesc scanDesc;
434 Snapshot snapshot;
435 TupleTableSlot *slot;
436
437 CheckTableNotInUse(event_relation, "CREATE RULE");
438
439 if (event_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
440 ereport(ERROR,
441 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
442 errmsg("cannot convert partitioned table \"%s\" to a view",
443 RelationGetRelationName(event_relation))));
444
445 /* only case left: */
446 Assert(event_relation->rd_rel->relkind == RELKIND_RELATION);
447
448 if (event_relation->rd_rel->relispartition)
449 ereport(ERROR,
450 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
451 errmsg("cannot convert partition \"%s\" to a view",
452 RelationGetRelationName(event_relation))));
453
454 snapshot = RegisterSnapshot(GetLatestSnapshot());
455 scanDesc = table_beginscan(event_relation, snapshot, 0, NULL);
456 slot = table_slot_create(event_relation, NULL);
457 if (table_scan_getnextslot(scanDesc, ForwardScanDirection, slot))
458 ereport(ERROR,
459 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
460 errmsg("could not convert table \"%s\" to a view because it is not empty",
461 RelationGetRelationName(event_relation))));
462 ExecDropSingleTupleTableSlot(slot);
463 table_endscan(scanDesc);
464 UnregisterSnapshot(snapshot);
465
466 if (event_relation->rd_rel->relhastriggers)
467 ereport(ERROR,
468 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
469 errmsg("could not convert table \"%s\" to a view because it has triggers",
470 RelationGetRelationName(event_relation)),
471 errhint("In particular, the table cannot be involved in any foreign key relationships.")));
472
473 if (event_relation->rd_rel->relhasindex)
474 ereport(ERROR,
475 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
476 errmsg("could not convert table \"%s\" to a view because it has indexes",
477 RelationGetRelationName(event_relation))));
478
479 if (event_relation->rd_rel->relhassubclass)
480 ereport(ERROR,
481 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
482 errmsg("could not convert table \"%s\" to a view because it has child tables",
483 RelationGetRelationName(event_relation))));
484
485 if (has_superclass(RelationGetRelid(event_relation)))
486 ereport(ERROR,
487 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
488 errmsg("could not convert table \"%s\" to a view because it has parent tables",
489 RelationGetRelationName(event_relation))));
490
491 if (event_relation->rd_rel->relrowsecurity)
492 ereport(ERROR,
493 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
494 errmsg("could not convert table \"%s\" to a view because it has row security enabled",
495 RelationGetRelationName(event_relation))));
496
497 if (relation_has_policies(event_relation))
498 ereport(ERROR,
499 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
500 errmsg("could not convert table \"%s\" to a view because it has row security policies",
501 RelationGetRelationName(event_relation))));
502
503 RelisBecomingView = true;
504 }
505 }
506 else
507 {
508 /*
509 * For non-SELECT rules, a RETURNING list can appear in at most one of
510 * the actions ... and there can't be any RETURNING list at all in a
511 * conditional or non-INSTEAD rule. (Actually, there can be at most
512 * one RETURNING list across all rules on the same event, but it seems
513 * best to enforce that at rule expansion time.) If there is a
514 * RETURNING list, it must match the event relation.
515 */
516 bool haveReturning = false;
517
518 foreach(l, action)
519 {
520 query = lfirst_node(Query, l);
521
522 if (!query->returningList)
523 continue;
524 if (haveReturning)
525 ereport(ERROR,
526 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
527 errmsg("cannot have multiple RETURNING lists in a rule")));
528 haveReturning = true;
529 if (event_qual != NULL)
530 ereport(ERROR,
531 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
532 errmsg("RETURNING lists are not supported in conditional rules")));
533 if (!is_instead)
534 ereport(ERROR,
535 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
536 errmsg("RETURNING lists are not supported in non-INSTEAD rules")));
537 checkRuleResultList(query->returningList,
538 RelationGetDescr(event_relation),
539 false, false);
540 }
541
542 /*
543 * And finally, if it's not an ON SELECT rule then it must *not* be
544 * named _RETURN. This prevents accidentally or maliciously replacing
545 * a view's ON SELECT rule with some other kind of rule.
546 */
547 if (strcmp(rulename, ViewSelectRuleName) == 0)
548 ereport(ERROR,
549 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
550 errmsg("non-view rule for \"%s\" must not be named \"%s\"",
551 RelationGetRelationName(event_relation),
552 ViewSelectRuleName)));
553 }
554
555 /*
556 * This rule is allowed - prepare to install it.
557 */
558
559 /* discard rule if it's null action and not INSTEAD; it's a no-op */
560 if (action != NIL || is_instead)
561 {
562 ruleId = InsertRule(rulename,
563 event_type,
564 event_relid,
565 is_instead,
566 event_qual,
567 action,
568 replace);
569
570 /*
571 * Set pg_class 'relhasrules' field true for event relation.
572 *
573 * Important side effect: an SI notice is broadcast to force all
574 * backends (including me!) to update relcache entries with the new
575 * rule.
576 */
577 SetRelationRuleStatus(event_relid, true);
578 }
579
580 /* ---------------------------------------------------------------------
581 * If the relation is becoming a view:
582 * - delete the associated storage files
583 * - get rid of any system attributes in pg_attribute; a view shouldn't
584 * have any of those
585 * - remove the toast table; there is no need for it anymore, and its
586 * presence would make vacuum slightly more complicated
587 * - set relkind to RELKIND_VIEW, and adjust other pg_class fields
588 * to be appropriate for a view
589 *
590 * NB: we had better have AccessExclusiveLock to do this ...
591 * ---------------------------------------------------------------------
592 */
593 if (RelisBecomingView)
594 {
595 Relation relationRelation;
596 Oid toastrelid;
597 HeapTuple classTup;
598 Form_pg_class classForm;
599
600 relationRelation = table_open(RelationRelationId, RowExclusiveLock);
601 toastrelid = event_relation->rd_rel->reltoastrelid;
602
603 /* drop storage while table still looks like a table */
604 RelationDropStorage(event_relation);
605 DeleteSystemAttributeTuples(event_relid);
606
607 /*
608 * Drop the toast table if any. (This won't take care of updating the
609 * toast fields in the relation's own pg_class entry; we handle that
610 * below.)
611 */
612 if (OidIsValid(toastrelid))
613 {
614 ObjectAddress toastobject;
615
616 /*
617 * Delete the dependency of the toast relation on the main
618 * relation so we can drop the former without dropping the latter.
619 */
620 deleteDependencyRecordsFor(RelationRelationId, toastrelid,
621 false);
622
623 /* Make deletion of dependency record visible */
624 CommandCounterIncrement();
625
626 /* Now drop toast table, including its index */
627 toastobject.classId = RelationRelationId;
628 toastobject.objectId = toastrelid;
629 toastobject.objectSubId = 0;
630 performDeletion(&toastobject, DROP_RESTRICT,
631 PERFORM_DELETION_INTERNAL);
632 }
633
634 /*
635 * SetRelationRuleStatus may have updated the pg_class row, so we must
636 * advance the command counter before trying to update it again.
637 */
638 CommandCounterIncrement();
639
640 /*
641 * Fix pg_class entry to look like a normal view's, including setting
642 * the correct relkind and removal of reltoastrelid of the toast table
643 * we potentially removed above.
644 */
645 classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(event_relid));
646 if (!HeapTupleIsValid(classTup))
647 elog(ERROR, "cache lookup failed for relation %u", event_relid);
648 classForm = (Form_pg_class) GETSTRUCT(classTup);
649
650 classForm->relam = InvalidOid;
651 classForm->reltablespace = InvalidOid;
652 classForm->relpages = 0;
653 classForm->reltuples = 0;
654 classForm->relallvisible = 0;
655 classForm->reltoastrelid = InvalidOid;
656 classForm->relhasindex = false;
657 classForm->relkind = RELKIND_VIEW;
658 classForm->relfrozenxid = InvalidTransactionId;
659 classForm->relminmxid = InvalidMultiXactId;
660 classForm->relreplident = REPLICA_IDENTITY_NOTHING;
661
662 CatalogTupleUpdate(relationRelation, &classTup->t_self, classTup);
663
664 heap_freetuple(classTup);
665 table_close(relationRelation, RowExclusiveLock);
666 }
667
668 ObjectAddressSet(address, RewriteRelationId, ruleId);
669
670 /* Close rel, but keep lock till commit... */
671 table_close(event_relation, NoLock);
672
673 return address;
674 }
675
676 /*
677 * checkRuleResultList
678 * Verify that targetList produces output compatible with a tupledesc
679 *
680 * The targetList might be either a SELECT targetlist, or a RETURNING list;
681 * isSelect tells which. This is used for choosing error messages.
682 *
683 * A SELECT targetlist may optionally require that column names match.
684 */
685 static void
686 checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect,
687 bool requireColumnNameMatch)
688 {
689 ListCell *tllist;
690 int i;
691
692 /* Only a SELECT may require a column name match. */
693 Assert(isSelect || !requireColumnNameMatch);
694
695 i = 0;
696 foreach(tllist, targetList)
697 {
698 TargetEntry *tle = (TargetEntry *) lfirst(tllist);
699 Oid tletypid;
700 int32 tletypmod;
701 Form_pg_attribute attr;
702 char *attname;
703
704 /* resjunk entries may be ignored */
705 if (tle->resjunk)
706 continue;
707 i++;
708 if (i > resultDesc->natts)
709 ereport(ERROR,
710 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
711 isSelect ?
712 errmsg("SELECT rule's target list has too many entries") :
713 errmsg("RETURNING list has too many entries")));
714
715 attr = TupleDescAttr(resultDesc, i - 1);
716 attname = NameStr(attr->attname);
717
718 /*
719 * Disallow dropped columns in the relation. This is not really
720 * expected to happen when creating an ON SELECT rule. It'd be
721 * possible if someone tried to convert a relation with dropped
722 * columns to a view, but the only case we care about supporting
723 * table-to-view conversion for is pg_dump, and pg_dump won't do that.
724 *
725 * Unfortunately, the situation is also possible when adding a rule
726 * with RETURNING to a regular table, and rejecting that case is
727 * altogether more annoying. In principle we could support it by
728 * modifying the targetlist to include dummy NULL columns
729 * corresponding to the dropped columns in the tupdesc. However,
730 * places like ruleutils.c would have to be fixed to not process such
731 * entries, and that would take an uncertain and possibly rather large
732 * amount of work. (Note we could not dodge that by marking the dummy
733 * columns resjunk, since it's precisely the non-resjunk tlist columns
734 * that are expected to correspond to table columns.)
735 */
736 if (attr->attisdropped)
737 ereport(ERROR,
738 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
739 isSelect ?
740 errmsg("cannot convert relation containing dropped columns to view") :
741 errmsg("cannot create a RETURNING list for a relation containing dropped columns")));
742
743 /* Check name match if required; no need for two error texts here */
744 if (requireColumnNameMatch && strcmp(tle->resname, attname) != 0)
745 ereport(ERROR,
746 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
747 errmsg("SELECT rule's target entry %d has different column name from column \"%s\"",
748 i, attname),
749 errdetail("SELECT target entry is named \"%s\".",
750 tle->resname)));
751
752 /* Check type match. */
753 tletypid = exprType((Node *) tle->expr);
754 if (attr->atttypid != tletypid)
755 ereport(ERROR,
756 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
757 isSelect ?
758 errmsg("SELECT rule's target entry %d has different type from column \"%s\"",
759 i, attname) :
760 errmsg("RETURNING list's entry %d has different type from column \"%s\"",
761 i, attname),
762 isSelect ?
763 errdetail("SELECT target entry has type %s, but column has type %s.",
764 format_type_be(tletypid),
765 format_type_be(attr->atttypid)) :
766 errdetail("RETURNING list entry has type %s, but column has type %s.",
767 format_type_be(tletypid),
768 format_type_be(attr->atttypid))));
769
770 /*
771 * Allow typmods to be different only if one of them is -1, ie,
772 * "unspecified". This is necessary for cases like "numeric", where
773 * the table will have a filled-in default length but the select
774 * rule's expression will probably have typmod = -1.
775 */
776 tletypmod = exprTypmod((Node *) tle->expr);
777 if (attr->atttypmod != tletypmod &&
778 attr->atttypmod != -1 && tletypmod != -1)
779 ereport(ERROR,
780 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
781 isSelect ?
782 errmsg("SELECT rule's target entry %d has different size from column \"%s\"",
783 i, attname) :
784 errmsg("RETURNING list's entry %d has different size from column \"%s\"",
785 i, attname),
786 isSelect ?
787 errdetail("SELECT target entry has type %s, but column has type %s.",
788 format_type_with_typemod(tletypid, tletypmod),
789 format_type_with_typemod(attr->atttypid,
790 attr->atttypmod)) :
791 errdetail("RETURNING list entry has type %s, but column has type %s.",
792 format_type_with_typemod(tletypid, tletypmod),
793 format_type_with_typemod(attr->atttypid,
794 attr->atttypmod))));
795 }
796
797 if (i != resultDesc->natts)
798 ereport(ERROR,
799 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
800 isSelect ?
801 errmsg("SELECT rule's target list has too few entries") :
802 errmsg("RETURNING list has too few entries")));
803 }
804
805 /*
806 * setRuleCheckAsUser
807 * Recursively scan a query or expression tree and set the checkAsUser
808 * field to the given userid in all rtable entries.
809 *
810 * Note: for a view (ON SELECT rule), the checkAsUser field of the OLD
811 * RTE entry will be overridden when the view rule is expanded, and the
812 * checkAsUser field of the NEW entry is irrelevant because that entry's
813 * requiredPerms bits will always be zero. However, for other types of rules
814 * it's important to set these fields to match the rule owner. So we just set
815 * them always.
816 */
817 void
818 setRuleCheckAsUser(Node *node, Oid userid)
819 {
820 (void) setRuleCheckAsUser_walker(node, &userid);
821 }
822
823 static bool
824 setRuleCheckAsUser_walker(Node *node, Oid *context)
825 {
826 if (node == NULL)
827 return false;
828 if (IsA(node, Query))
829 {
830 setRuleCheckAsUser_Query((Query *) node, *context);
831 return false;
832 }
833 return expression_tree_walker(node, setRuleCheckAsUser_walker,
834 (void *) context);
835 }
836
837 static void
838 setRuleCheckAsUser_Query(Query *qry, Oid userid)
839 {
840 ListCell *l;
841
842 /* Set all the RTEs in this query node */
843 foreach(l, qry->rtable)
844 {
845 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
846
847 if (rte->rtekind == RTE_SUBQUERY)
848 {
849 /* Recurse into subquery in FROM */
850 setRuleCheckAsUser_Query(rte->subquery, userid);
851 }
852 else
853 rte->checkAsUser = userid;
854 }
855
856 /* Recurse into subquery-in-WITH */
857 foreach(l, qry->cteList)
858 {
859 CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
860
861 setRuleCheckAsUser_Query(castNode(Query, cte->ctequery), userid);
862 }
863
864 /* If there are sublinks, search for them and process their RTEs */
865 if (qry->hasSubLinks)
866 query_tree_walker(qry, setRuleCheckAsUser_walker, (void *) &userid,
867 QTW_IGNORE_RC_SUBQUERIES);
868 }
869
870
871 /*
872 * Change the firing semantics of an existing rule.
873 */
874 void
875 EnableDisableRule(Relation rel, const char *rulename,
876 char fires_when)
877 {
878 Relation pg_rewrite_desc;
879 Oid owningRel = RelationGetRelid(rel);
880 Oid eventRelationOid;
881 HeapTuple ruletup;
882 Form_pg_rewrite ruleform;
883 bool changed = false;
884
885 /*
886 * Find the rule tuple to change.
887 */
888 pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock);
889 ruletup = SearchSysCacheCopy2(RULERELNAME,
890 ObjectIdGetDatum(owningRel),
891 PointerGetDatum(rulename));
892 if (!HeapTupleIsValid(ruletup))
893 ereport(ERROR,
894 (errcode(ERRCODE_UNDEFINED_OBJECT),
895 errmsg("rule \"%s\" for relation \"%s\" does not exist",
896 rulename, get_rel_name(owningRel))));
897
898 ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup);
899
900 /*
901 * Verify that the user has appropriate permissions.
902 */
903 eventRelationOid = ruleform->ev_class;
904 Assert(eventRelationOid == owningRel);
905 if (!pg_class_ownercheck(eventRelationOid, GetUserId()))
906 aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(eventRelationOid)),
907 get_rel_name(eventRelationOid));
908
909 /*
910 * Change ev_enabled if it is different from the desired new state.
911 */
912 if (DatumGetChar(ruleform->ev_enabled) !=
913 fires_when)
914 {
915 ruleform->ev_enabled = CharGetDatum(fires_when);
916 CatalogTupleUpdate(pg_rewrite_desc, &ruletup->t_self, ruletup);
917
918 changed = true;
919 }
920
921 InvokeObjectPostAlterHook(RewriteRelationId, ruleform->oid, 0);
922
923 heap_freetuple(ruletup);
924 table_close(pg_rewrite_desc, RowExclusiveLock);
925
926 /*
927 * If we changed anything, broadcast a SI inval message to force each
928 * backend (including our own!) to rebuild relation's relcache entry.
929 * Otherwise they will fail to apply the change promptly.
930 */
931 if (changed)
932 CacheInvalidateRelcache(rel);
933 }
934
935
936 /*
937 * Perform permissions and integrity checks before acquiring a relation lock.
938 */
939 static void
940 RangeVarCallbackForRenameRule(const RangeVar *rv, Oid relid, Oid oldrelid,
941 void *arg)
942 {
943 HeapTuple tuple;
944 Form_pg_class form;
945
946 tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
947 if (!HeapTupleIsValid(tuple))
948 return; /* concurrently dropped */
949 form = (Form_pg_class) GETSTRUCT(tuple);
950
951 /* only tables and views can have rules */
952 if (form->relkind != RELKIND_RELATION &&
953 form->relkind != RELKIND_VIEW &&
954 form->relkind != RELKIND_PARTITIONED_TABLE)
955 ereport(ERROR,
956 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
957 errmsg("\"%s\" is not a table or view", rv->relname)));
958
959 if (!allowSystemTableMods && IsSystemClass(relid, form))
960 ereport(ERROR,
961 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
962 errmsg("permission denied: \"%s\" is a system catalog",
963 rv->relname)));
964
965 /* you must own the table to rename one of its rules */
966 if (!pg_class_ownercheck(relid, GetUserId()))
967 aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
968
969 ReleaseSysCache(tuple);
970 }
971
972 /*
973 * Rename an existing rewrite rule.
974 */
975 ObjectAddress
976 RenameRewriteRule(RangeVar *relation, const char *oldName,
977 const char *newName)
978 {
979 Oid relid;
980 Relation targetrel;
981 Relation pg_rewrite_desc;
982 HeapTuple ruletup;
983 Form_pg_rewrite ruleform;
984 Oid ruleOid;
985 ObjectAddress address;
986
987 /*
988 * Look up name, check permissions, and acquire lock (which we will NOT
989 * release until end of transaction).
990 */
991 relid = RangeVarGetRelidExtended(relation, AccessExclusiveLock,
992 0,
993 RangeVarCallbackForRenameRule,
994 NULL);
995
996 /* Have lock already, so just need to build relcache entry. */
997 targetrel = relation_open(relid, NoLock);
998
999 /* Prepare to modify pg_rewrite */
1000 pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock);
1001
1002 /* Fetch the rule's entry (it had better exist) */
1003 ruletup = SearchSysCacheCopy2(RULERELNAME,
1004 ObjectIdGetDatum(relid),
1005 PointerGetDatum(oldName));
1006 if (!HeapTupleIsValid(ruletup))
1007 ereport(ERROR,
1008 (errcode(ERRCODE_UNDEFINED_OBJECT),
1009 errmsg("rule \"%s\" for relation \"%s\" does not exist",
1010 oldName, RelationGetRelationName(targetrel))));
1011 ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup);
1012 ruleOid = ruleform->oid;
1013
1014 /* rule with the new name should not already exist */
1015 if (IsDefinedRewriteRule(relid, newName))
1016 ereport(ERROR,
1017 (errcode(ERRCODE_DUPLICATE_OBJECT),
1018 errmsg("rule \"%s\" for relation \"%s\" already exists",
1019 newName, RelationGetRelationName(targetrel))));
1020
1021 /*
1022 * We disallow renaming ON SELECT rules, because they should always be
1023 * named "_RETURN".
1024 */
1025 if (ruleform->ev_type == CMD_SELECT + '0')
1026 ereport(ERROR,
1027 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
1028 errmsg("renaming an ON SELECT rule is not allowed")));
1029
1030 /* OK, do the update */
1031 namestrcpy(&(ruleform->rulename), newName);
1032
1033 CatalogTupleUpdate(pg_rewrite_desc, &ruletup->t_self, ruletup);
1034
1035 heap_freetuple(ruletup);
1036 table_close(pg_rewrite_desc, RowExclusiveLock);
1037
1038 /*
1039 * Invalidate relation's relcache entry so that other backends (and this
1040 * one too!) are sent SI message to make them rebuild relcache entries.
1041 * (Ideally this should happen automatically...)
1042 */
1043 CacheInvalidateRelcache(targetrel);
1044
1045 ObjectAddressSet(address, RewriteRelationId, ruleOid);
1046
1047 /*
1048 * Close rel, but keep exclusive lock!
1049 */
1050 relation_close(targetrel, NoLock);
1051
1052 return address;
1053 }
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