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Revert commit 66c0185a3 and follow-on patches.
[pgsql.git] / src / backend / rewrite / rewriteDefine.c
blob6cc9a8d8bfe9052c0c6f57c05ab4c2c7527a6d9d
1 /*-------------------------------------------------------------------------
2 *
3 * rewriteDefine.c
4 * routines for defining a rewrite rule
5 *
6 * Portions Copyright (c) 1996-2024, 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/htup_details.h"
18 #include "access/relation.h"
19 #include "access/table.h"
20 #include "catalog/catalog.h"
21 #include "catalog/dependency.h"
22 #include "catalog/indexing.h"
23 #include "catalog/namespace.h"
24 #include "catalog/objectaccess.h"
25 #include "catalog/pg_rewrite.h"
26 #include "miscadmin.h"
27 #include "nodes/nodeFuncs.h"
28 #include "parser/parse_utilcmd.h"
29 #include "rewrite/rewriteDefine.h"
30 #include "rewrite/rewriteManip.h"
31 #include "rewrite/rewriteSupport.h"
32 #include "utils/acl.h"
33 #include "utils/builtins.h"
34 #include "utils/inval.h"
35 #include "utils/lsyscache.h"
36 #include "utils/rel.h"
37 #include "utils/syscache.h"
38
39
40 static void checkRuleResultList(List *targetList, TupleDesc resultDesc,
41 bool isSelect, bool requireColumnNameMatch);
42 static bool setRuleCheckAsUser_walker(Node *node, Oid *context);
43 static void setRuleCheckAsUser_Query(Query *qry, Oid userid);
44
45
46 /*
47 * InsertRule -
48 * takes the arguments and inserts them as a row into the system
49 * relation "pg_rewrite"
50 */
51 static Oid
52 InsertRule(const char *rulname,
53 int evtype,
54 Oid eventrel_oid,
55 bool evinstead,
56 Node *event_qual,
57 List *action,
58 bool replace)
59 {
60 char *evqual = nodeToString(event_qual);
61 char *actiontree = nodeToString((Node *) action);
62 Datum values[Natts_pg_rewrite];
63 bool nulls[Natts_pg_rewrite] = {0};
64 NameData rname;
65 Relation pg_rewrite_desc;
66 HeapTuple tup,
67 oldtup;
68 Oid rewriteObjectId;
69 ObjectAddress myself,
70 referenced;
71 bool is_update = false;
72
73 /*
74 * Set up *nulls and *values arrays
75 */
76 namestrcpy(&rname, rulname);
77 values[Anum_pg_rewrite_rulename - 1] = NameGetDatum(&rname);
78 values[Anum_pg_rewrite_ev_class - 1] = ObjectIdGetDatum(eventrel_oid);
79 values[Anum_pg_rewrite_ev_type - 1] = CharGetDatum(evtype + '0');
80 values[Anum_pg_rewrite_ev_enabled - 1] = CharGetDatum(RULE_FIRES_ON_ORIGIN);
81 values[Anum_pg_rewrite_is_instead - 1] = BoolGetDatum(evinstead);
82 values[Anum_pg_rewrite_ev_qual - 1] = CStringGetTextDatum(evqual);
83 values[Anum_pg_rewrite_ev_action - 1] = CStringGetTextDatum(actiontree);
84
85 /*
86 * Ready to store new pg_rewrite tuple
87 */
88 pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock);
89
90 /*
91 * Check to see if we are replacing an existing tuple
92 */
93 oldtup = SearchSysCache2(RULERELNAME,
94 ObjectIdGetDatum(eventrel_oid),
95 PointerGetDatum(rulname));
96
97 if (HeapTupleIsValid(oldtup))
98 {
99 bool replaces[Natts_pg_rewrite] = {0};
100
101 if (!replace)
102 ereport(ERROR,
103 (errcode(ERRCODE_DUPLICATE_OBJECT),
104 errmsg("rule \"%s\" for relation \"%s\" already exists",
105 rulname, get_rel_name(eventrel_oid))));
106
107 /*
108 * When replacing, we don't need to replace every attribute
109 */
110 replaces[Anum_pg_rewrite_ev_type - 1] = true;
111 replaces[Anum_pg_rewrite_is_instead - 1] = true;
112 replaces[Anum_pg_rewrite_ev_qual - 1] = true;
113 replaces[Anum_pg_rewrite_ev_action - 1] = true;
114
115 tup = heap_modify_tuple(oldtup, RelationGetDescr(pg_rewrite_desc),
116 values, nulls, replaces);
117
118 CatalogTupleUpdate(pg_rewrite_desc, &tup->t_self, tup);
119
120 ReleaseSysCache(oldtup);
121
122 rewriteObjectId = ((Form_pg_rewrite) GETSTRUCT(tup))->oid;
123 is_update = true;
124 }
125 else
126 {
127 rewriteObjectId = GetNewOidWithIndex(pg_rewrite_desc,
128 RewriteOidIndexId,
129 Anum_pg_rewrite_oid);
130 values[Anum_pg_rewrite_oid - 1] = ObjectIdGetDatum(rewriteObjectId);
131
132 tup = heap_form_tuple(pg_rewrite_desc->rd_att, values, nulls);
133
134 CatalogTupleInsert(pg_rewrite_desc, tup);
135 }
136
137
138 heap_freetuple(tup);
139
140 /* If replacing, get rid of old dependencies and make new ones */
141 if (is_update)
142 deleteDependencyRecordsFor(RewriteRelationId, rewriteObjectId, false);
143
144 /*
145 * Install dependency on rule's relation to ensure it will go away on
146 * relation deletion. If the rule is ON SELECT, make the dependency
147 * implicit --- this prevents deleting a view's SELECT rule. Other kinds
148 * of rules can be AUTO.
149 */
150 myself.classId = RewriteRelationId;
151 myself.objectId = rewriteObjectId;
152 myself.objectSubId = 0;
153
154 referenced.classId = RelationRelationId;
155 referenced.objectId = eventrel_oid;
156 referenced.objectSubId = 0;
157
158 recordDependencyOn(&myself, &referenced,
159 (evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
160
161 /*
162 * Also install dependencies on objects referenced in action and qual.
163 */
164 recordDependencyOnExpr(&myself, (Node *) action, NIL,
165 DEPENDENCY_NORMAL);
166
167 if (event_qual != NULL)
168 {
169 /* Find query containing OLD/NEW rtable entries */
170 Query *qry = linitial_node(Query, action);
171
172 qry = getInsertSelectQuery(qry, NULL);
173 recordDependencyOnExpr(&myself, event_qual, qry->rtable,
174 DEPENDENCY_NORMAL);
175 }
176
177 /* Post creation hook for new rule */
178 InvokeObjectPostCreateHook(RewriteRelationId, rewriteObjectId, 0);
179
180 table_close(pg_rewrite_desc, RowExclusiveLock);
181
182 return rewriteObjectId;
183 }
184
185 /*
186 * DefineRule
187 * Execute a CREATE RULE command.
188 */
189 ObjectAddress
190 DefineRule(RuleStmt *stmt, const char *queryString)
191 {
192 List *actions;
193 Node *whereClause;
194 Oid relId;
195
196 /* Parse analysis. */
197 transformRuleStmt(stmt, queryString, &actions, &whereClause);
198
199 /*
200 * Find and lock the relation. Lock level should match
201 * DefineQueryRewrite.
202 */
203 relId = RangeVarGetRelid(stmt->relation, AccessExclusiveLock, false);
204
205 /* ... and execute */
206 return DefineQueryRewrite(stmt->rulename,
207 relId,
208 whereClause,
209 stmt->event,
210 stmt->instead,
211 stmt->replace,
212 actions);
213 }
214
215
216 /*
217 * DefineQueryRewrite
218 * Create a rule
219 *
220 * This is essentially the same as DefineRule() except that the rule's
221 * action and qual have already been passed through parse analysis.
222 */
223 ObjectAddress
224 DefineQueryRewrite(const char *rulename,
225 Oid event_relid,
226 Node *event_qual,
227 CmdType event_type,
228 bool is_instead,
229 bool replace,
230 List *action)
231 {
232 Relation event_relation;
233 ListCell *l;
234 Query *query;
235 Oid ruleId = InvalidOid;
236 ObjectAddress address;
237
238 /*
239 * If we are installing an ON SELECT rule, we had better grab
240 * AccessExclusiveLock to ensure no SELECTs are currently running on the
241 * event relation. For other types of rules, it would be sufficient to
242 * grab ShareRowExclusiveLock to lock out insert/update/delete actions and
243 * to ensure that we lock out current CREATE RULE statements; but because
244 * of race conditions in access to catalog entries, we can't do that yet.
245 *
246 * Note that this lock level should match the one used in DefineRule.
247 */
248 event_relation = table_open(event_relid, AccessExclusiveLock);
249
250 /*
251 * Verify relation is of a type that rules can sensibly be applied to.
252 * Internal callers can target materialized views, but transformRuleStmt()
253 * blocks them for users. Don't mention them in the error message.
254 */
255 if (event_relation->rd_rel->relkind != RELKIND_RELATION &&
256 event_relation->rd_rel->relkind != RELKIND_MATVIEW &&
257 event_relation->rd_rel->relkind != RELKIND_VIEW &&
258 event_relation->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
259 ereport(ERROR,
260 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
261 errmsg("relation \"%s\" cannot have rules",
262 RelationGetRelationName(event_relation)),
263 errdetail_relkind_not_supported(event_relation->rd_rel->relkind)));
264
265 if (!allowSystemTableMods && IsSystemRelation(event_relation))
266 ereport(ERROR,
267 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
268 errmsg("permission denied: \"%s\" is a system catalog",
269 RelationGetRelationName(event_relation))));
270
271 /*
272 * Check user has permission to apply rules to this relation.
273 */
274 if (!object_ownercheck(RelationRelationId, event_relid, GetUserId()))
275 aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(event_relation->rd_rel->relkind),
276 RelationGetRelationName(event_relation));
277
278 /*
279 * No rule actions that modify OLD or NEW
280 */
281 foreach(l, action)
282 {
283 query = lfirst_node(Query, l);
284 if (query->resultRelation == 0)
285 continue;
286 /* Don't be fooled by INSERT/SELECT */
287 if (query != getInsertSelectQuery(query, NULL))
288 continue;
289 if (query->resultRelation == PRS2_OLD_VARNO)
290 ereport(ERROR,
291 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
292 errmsg("rule actions on OLD are not implemented"),
293 errhint("Use views or triggers instead.")));
294 if (query->resultRelation == PRS2_NEW_VARNO)
295 ereport(ERROR,
296 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
297 errmsg("rule actions on NEW are not implemented"),
298 errhint("Use triggers instead.")));
299 }
300
301 if (event_type == CMD_SELECT)
302 {
303 /*
304 * Rules ON SELECT are restricted to view definitions
305 *
306 * So this had better be a view, ...
307 */
308 if (event_relation->rd_rel->relkind != RELKIND_VIEW &&
309 event_relation->rd_rel->relkind != RELKIND_MATVIEW)
310 ereport(ERROR,
311 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
312 errmsg("relation \"%s\" cannot have ON SELECT rules",
313 RelationGetRelationName(event_relation)),
314 errdetail_relkind_not_supported(event_relation->rd_rel->relkind)));
315
316 /*
317 * ... there cannot be INSTEAD NOTHING, ...
318 */
319 if (action == NIL)
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 else
415 {
416 /*
417 * For non-SELECT rules, a RETURNING list can appear in at most one of
418 * the actions ... and there can't be any RETURNING list at all in a
419 * conditional or non-INSTEAD rule. (Actually, there can be at most
420 * one RETURNING list across all rules on the same event, but it seems
421 * best to enforce that at rule expansion time.) If there is a
422 * RETURNING list, it must match the event relation.
423 */
424 bool haveReturning = false;
425
426 foreach(l, action)
427 {
428 query = lfirst_node(Query, l);
429
430 if (!query->returningList)
431 continue;
432 if (haveReturning)
433 ereport(ERROR,
434 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
435 errmsg("cannot have multiple RETURNING lists in a rule")));
436 haveReturning = true;
437 if (event_qual != NULL)
438 ereport(ERROR,
439 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
440 errmsg("RETURNING lists are not supported in conditional rules")));
441 if (!is_instead)
442 ereport(ERROR,
443 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
444 errmsg("RETURNING lists are not supported in non-INSTEAD rules")));
445 checkRuleResultList(query->returningList,
446 RelationGetDescr(event_relation),
447 false, false);
448 }
449
450 /*
451 * And finally, if it's not an ON SELECT rule then it must *not* be
452 * named _RETURN. This prevents accidentally or maliciously replacing
453 * a view's ON SELECT rule with some other kind of rule.
454 */
455 if (strcmp(rulename, ViewSelectRuleName) == 0)
456 ereport(ERROR,
457 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
458 errmsg("non-view rule for \"%s\" must not be named \"%s\"",
459 RelationGetRelationName(event_relation),
460 ViewSelectRuleName)));
461 }
462
463 /*
464 * This rule is allowed - prepare to install it.
465 */
466
467 /* discard rule if it's null action and not INSTEAD; it's a no-op */
468 if (action != NIL || is_instead)
469 {
470 ruleId = InsertRule(rulename,
471 event_type,
472 event_relid,
473 is_instead,
474 event_qual,
475 action,
476 replace);
477
478 /*
479 * Set pg_class 'relhasrules' field true for event relation.
480 *
481 * Important side effect: an SI notice is broadcast to force all
482 * backends (including me!) to update relcache entries with the new
483 * rule.
484 */
485 SetRelationRuleStatus(event_relid, true);
486 }
487
488 ObjectAddressSet(address, RewriteRelationId, ruleId);
489
490 /* Close rel, but keep lock till commit... */
491 table_close(event_relation, NoLock);
492
493 return address;
494 }
495
496 /*
497 * checkRuleResultList
498 * Verify that targetList produces output compatible with a tupledesc
499 *
500 * The targetList might be either a SELECT targetlist, or a RETURNING list;
501 * isSelect tells which. This is used for choosing error messages.
502 *
503 * A SELECT targetlist may optionally require that column names match.
504 */
505 static void
506 checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect,
507 bool requireColumnNameMatch)
508 {
509 ListCell *tllist;
510 int i;
511
512 /* Only a SELECT may require a column name match. */
513 Assert(isSelect || !requireColumnNameMatch);
514
515 i = 0;
516 foreach(tllist, targetList)
517 {
518 TargetEntry *tle = (TargetEntry *) lfirst(tllist);
519 Oid tletypid;
520 int32 tletypmod;
521 Form_pg_attribute attr;
522 char *attname;
523
524 /* resjunk entries may be ignored */
525 if (tle->resjunk)
526 continue;
527 i++;
528 if (i > resultDesc->natts)
529 ereport(ERROR,
530 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
531 isSelect ?
532 errmsg("SELECT rule's target list has too many entries") :
533 errmsg("RETURNING list has too many entries")));
534
535 attr = TupleDescAttr(resultDesc, i - 1);
536 attname = NameStr(attr->attname);
537
538 /*
539 * Disallow dropped columns in the relation. This is not really
540 * expected to happen when creating an ON SELECT rule. It'd be
541 * possible if someone tried to convert a relation with dropped
542 * columns to a view, but the only case we care about supporting
543 * table-to-view conversion for is pg_dump, and pg_dump won't do that.
544 *
545 * Unfortunately, the situation is also possible when adding a rule
546 * with RETURNING to a regular table, and rejecting that case is
547 * altogether more annoying. In principle we could support it by
548 * modifying the targetlist to include dummy NULL columns
549 * corresponding to the dropped columns in the tupdesc. However,
550 * places like ruleutils.c would have to be fixed to not process such
551 * entries, and that would take an uncertain and possibly rather large
552 * amount of work. (Note we could not dodge that by marking the dummy
553 * columns resjunk, since it's precisely the non-resjunk tlist columns
554 * that are expected to correspond to table columns.)
555 */
556 if (attr->attisdropped)
557 ereport(ERROR,
558 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
559 isSelect ?
560 errmsg("cannot convert relation containing dropped columns to view") :
561 errmsg("cannot create a RETURNING list for a relation containing dropped columns")));
562
563 /* Check name match if required; no need for two error texts here */
564 if (requireColumnNameMatch && strcmp(tle->resname, attname) != 0)
565 ereport(ERROR,
566 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
567 errmsg("SELECT rule's target entry %d has different column name from column \"%s\"",
568 i, attname),
569 errdetail("SELECT target entry is named \"%s\".",
570 tle->resname)));
571
572 /* Check type match. */
573 tletypid = exprType((Node *) tle->expr);
574 if (attr->atttypid != tletypid)
575 ereport(ERROR,
576 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
577 isSelect ?
578 errmsg("SELECT rule's target entry %d has different type from column \"%s\"",
579 i, attname) :
580 errmsg("RETURNING list's entry %d has different type from column \"%s\"",
581 i, attname),
582 isSelect ?
583 errdetail("SELECT target entry has type %s, but column has type %s.",
584 format_type_be(tletypid),
585 format_type_be(attr->atttypid)) :
586 errdetail("RETURNING list entry has type %s, but column has type %s.",
587 format_type_be(tletypid),
588 format_type_be(attr->atttypid))));
589
590 /*
591 * Allow typmods to be different only if one of them is -1, ie,
592 * "unspecified". This is necessary for cases like "numeric", where
593 * the table will have a filled-in default length but the select
594 * rule's expression will probably have typmod = -1.
595 */
596 tletypmod = exprTypmod((Node *) tle->expr);
597 if (attr->atttypmod != tletypmod &&
598 attr->atttypmod != -1 && tletypmod != -1)
599 ereport(ERROR,
600 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
601 isSelect ?
602 errmsg("SELECT rule's target entry %d has different size from column \"%s\"",
603 i, attname) :
604 errmsg("RETURNING list's entry %d has different size from column \"%s\"",
605 i, attname),
606 isSelect ?
607 errdetail("SELECT target entry has type %s, but column has type %s.",
608 format_type_with_typemod(tletypid, tletypmod),
609 format_type_with_typemod(attr->atttypid,
610 attr->atttypmod)) :
611 errdetail("RETURNING list entry has type %s, but column has type %s.",
612 format_type_with_typemod(tletypid, tletypmod),
613 format_type_with_typemod(attr->atttypid,
614 attr->atttypmod))));
615 }
616
617 if (i != resultDesc->natts)
618 ereport(ERROR,
619 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
620 isSelect ?
621 errmsg("SELECT rule's target list has too few entries") :
622 errmsg("RETURNING list has too few entries")));
623 }
624
625 /*
626 * setRuleCheckAsUser
627 * Recursively scan a query or expression tree and set the checkAsUser
628 * field to the given userid in all RTEPermissionInfos of the query.
629 */
630 void
631 setRuleCheckAsUser(Node *node, Oid userid)
632 {
633 (void) setRuleCheckAsUser_walker(node, &userid);
634 }
635
636 static bool
637 setRuleCheckAsUser_walker(Node *node, Oid *context)
638 {
639 if (node == NULL)
640 return false;
641 if (IsA(node, Query))
642 {
643 setRuleCheckAsUser_Query((Query *) node, *context);
644 return false;
645 }
646 return expression_tree_walker(node, setRuleCheckAsUser_walker,
647 (void *) context);
648 }
649
650 static void
651 setRuleCheckAsUser_Query(Query *qry, Oid userid)
652 {
653 ListCell *l;
654
655 /* Set in all RTEPermissionInfos for this query. */
656 foreach(l, qry->rteperminfos)
657 {
658 RTEPermissionInfo *perminfo = lfirst_node(RTEPermissionInfo, l);
659
660 perminfo->checkAsUser = userid;
661 }
662
663 /* Now recurse to any subquery RTEs */
664 foreach(l, qry->rtable)
665 {
666 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
667
668 if (rte->rtekind == RTE_SUBQUERY)
669 setRuleCheckAsUser_Query(rte->subquery, userid);
670 }
671
672 /* Recurse into subquery-in-WITH */
673 foreach(l, qry->cteList)
674 {
675 CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
676
677 setRuleCheckAsUser_Query(castNode(Query, cte->ctequery), userid);
678 }
679
680 /* If there are sublinks, search for them and process their RTEs */
681 if (qry->hasSubLinks)
682 query_tree_walker(qry, setRuleCheckAsUser_walker, (void *) &userid,
683 QTW_IGNORE_RC_SUBQUERIES);
684 }
685
686
687 /*
688 * Change the firing semantics of an existing rule.
689 */
690 void
691 EnableDisableRule(Relation rel, const char *rulename,
692 char fires_when)
693 {
694 Relation pg_rewrite_desc;
695 Oid owningRel = RelationGetRelid(rel);
696 Oid eventRelationOid;
697 HeapTuple ruletup;
698 Form_pg_rewrite ruleform;
699 bool changed = false;
700
701 /*
702 * Find the rule tuple to change.
703 */
704 pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock);
705 ruletup = SearchSysCacheCopy2(RULERELNAME,
706 ObjectIdGetDatum(owningRel),
707 PointerGetDatum(rulename));
708 if (!HeapTupleIsValid(ruletup))
709 ereport(ERROR,
710 (errcode(ERRCODE_UNDEFINED_OBJECT),
711 errmsg("rule \"%s\" for relation \"%s\" does not exist",
712 rulename, get_rel_name(owningRel))));
713
714 ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup);
715
716 /*
717 * Verify that the user has appropriate permissions.
718 */
719 eventRelationOid = ruleform->ev_class;
720 Assert(eventRelationOid == owningRel);
721 if (!object_ownercheck(RelationRelationId, eventRelationOid, GetUserId()))
722 aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(eventRelationOid)),
723 get_rel_name(eventRelationOid));
724
725 /*
726 * Change ev_enabled if it is different from the desired new state.
727 */
728 if (DatumGetChar(ruleform->ev_enabled) !=
729 fires_when)
730 {
731 ruleform->ev_enabled = CharGetDatum(fires_when);
732 CatalogTupleUpdate(pg_rewrite_desc, &ruletup->t_self, ruletup);
733
734 changed = true;
735 }
736
737 InvokeObjectPostAlterHook(RewriteRelationId, ruleform->oid, 0);
738
739 heap_freetuple(ruletup);
740 table_close(pg_rewrite_desc, RowExclusiveLock);
741
742 /*
743 * If we changed anything, broadcast a SI inval message to force each
744 * backend (including our own!) to rebuild relation's relcache entry.
745 * Otherwise they will fail to apply the change promptly.
746 */
747 if (changed)
748 CacheInvalidateRelcache(rel);
749 }
750
751
752 /*
753 * Perform permissions and integrity checks before acquiring a relation lock.
754 */
755 static void
756 RangeVarCallbackForRenameRule(const RangeVar *rv, Oid relid, Oid oldrelid,
757 void *arg)
758 {
759 HeapTuple tuple;
760 Form_pg_class form;
761
762 tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
763 if (!HeapTupleIsValid(tuple))
764 return; /* concurrently dropped */
765 form = (Form_pg_class) GETSTRUCT(tuple);
766
767 /* only tables and views can have rules */
768 if (form->relkind != RELKIND_RELATION &&
769 form->relkind != RELKIND_VIEW &&
770 form->relkind != RELKIND_PARTITIONED_TABLE)
771 ereport(ERROR,
772 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
773 errmsg("relation \"%s\" cannot have rules", rv->relname),
774 errdetail_relkind_not_supported(form->relkind)));
775
776 if (!allowSystemTableMods && IsSystemClass(relid, form))
777 ereport(ERROR,
778 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
779 errmsg("permission denied: \"%s\" is a system catalog",
780 rv->relname)));
781
782 /* you must own the table to rename one of its rules */
783 if (!object_ownercheck(RelationRelationId, relid, GetUserId()))
784 aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
785
786 ReleaseSysCache(tuple);
787 }
788
789 /*
790 * Rename an existing rewrite rule.
791 */
792 ObjectAddress
793 RenameRewriteRule(RangeVar *relation, const char *oldName,
794 const char *newName)
795 {
796 Oid relid;
797 Relation targetrel;
798 Relation pg_rewrite_desc;
799 HeapTuple ruletup;
800 Form_pg_rewrite ruleform;
801 Oid ruleOid;
802 ObjectAddress address;
803
804 /*
805 * Look up name, check permissions, and acquire lock (which we will NOT
806 * release until end of transaction).
807 */
808 relid = RangeVarGetRelidExtended(relation, AccessExclusiveLock,
809 0,
810 RangeVarCallbackForRenameRule,
811 NULL);
812
813 /* Have lock already, so just need to build relcache entry. */
814 targetrel = relation_open(relid, NoLock);
815
816 /* Prepare to modify pg_rewrite */
817 pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock);
818
819 /* Fetch the rule's entry (it had better exist) */
820 ruletup = SearchSysCacheCopy2(RULERELNAME,
821 ObjectIdGetDatum(relid),
822 PointerGetDatum(oldName));
823 if (!HeapTupleIsValid(ruletup))
824 ereport(ERROR,
825 (errcode(ERRCODE_UNDEFINED_OBJECT),
826 errmsg("rule \"%s\" for relation \"%s\" does not exist",
827 oldName, RelationGetRelationName(targetrel))));
828 ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup);
829 ruleOid = ruleform->oid;
830
831 /* rule with the new name should not already exist */
832 if (IsDefinedRewriteRule(relid, newName))
833 ereport(ERROR,
834 (errcode(ERRCODE_DUPLICATE_OBJECT),
835 errmsg("rule \"%s\" for relation \"%s\" already exists",
836 newName, RelationGetRelationName(targetrel))));
837
838 /*
839 * We disallow renaming ON SELECT rules, because they should always be
840 * named "_RETURN".
841 */
842 if (ruleform->ev_type == CMD_SELECT + '0')
843 ereport(ERROR,
844 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
845 errmsg("renaming an ON SELECT rule is not allowed")));
846
847 /* OK, do the update */
848 namestrcpy(&(ruleform->rulename), newName);
849
850 CatalogTupleUpdate(pg_rewrite_desc, &ruletup->t_self, ruletup);
851
852 InvokeObjectPostAlterHook(RewriteRelationId, ruleOid, 0);
853
854 heap_freetuple(ruletup);
855 table_close(pg_rewrite_desc, RowExclusiveLock);
856
857 /*
858 * Invalidate relation's relcache entry so that other backends (and this
859 * one too!) are sent SI message to make them rebuild relcache entries.
860 * (Ideally this should happen automatically...)
861 */
862 CacheInvalidateRelcache(targetrel);
863
864 ObjectAddressSet(address, RewriteRelationId, ruleOid);
865
866 /*
867 * Close rel, but keep exclusive lock!
868 */
869 relation_close(targetrel, NoLock);
870
871 return address;
872 }
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