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Diffstat (limited to 'src/backend/rewrite/rewriteDefine.c')
| -rw-r--r-- | src/backend/rewrite/rewriteDefine.c | 1050 |
1 files changed, 1050 insertions, 0 deletions
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c new file mode 100644 index 0000000..a354969 --- /dev/null +++ b/src/backend/rewrite/rewriteDefine.c @@ -0,0 +1,1050 @@ +/*------------------------------------------------------------------------- + * + * rewriteDefine.c + * routines for defining a rewrite rule + * + * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/rewrite/rewriteDefine.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "access/heapam.h" +#include "access/htup_details.h" +#include "access/multixact.h" +#include "access/tableam.h" +#include "access/transam.h" +#include "access/xact.h" +#include "catalog/catalog.h" +#include "catalog/dependency.h" +#include "catalog/heap.h" +#include "catalog/namespace.h" +#include "catalog/objectaccess.h" +#include "catalog/pg_inherits.h" +#include "catalog/pg_rewrite.h" +#include "catalog/storage.h" +#include "commands/policy.h" +#include "miscadmin.h" +#include "nodes/nodeFuncs.h" +#include "parser/parse_utilcmd.h" +#include "rewrite/rewriteDefine.h" +#include "rewrite/rewriteManip.h" +#include "rewrite/rewriteSupport.h" +#include "utils/acl.h" +#include "utils/builtins.h" +#include "utils/inval.h" +#include "utils/lsyscache.h" +#include "utils/rel.h" +#include "utils/snapmgr.h" +#include "utils/syscache.h" + + +static void checkRuleResultList(List *targetList, TupleDesc resultDesc, + bool isSelect, bool requireColumnNameMatch); +static bool setRuleCheckAsUser_walker(Node *node, Oid *context); +static void setRuleCheckAsUser_Query(Query *qry, Oid userid); + + +/* + * InsertRule - + * takes the arguments and inserts them as a row into the system + * relation "pg_rewrite" + */ +static Oid +InsertRule(const char *rulname, + int evtype, + Oid eventrel_oid, + bool evinstead, + Node *event_qual, + List *action, + bool replace) +{ + char *evqual = nodeToString(event_qual); + char *actiontree = nodeToString((Node *) action); + Datum values[Natts_pg_rewrite]; + bool nulls[Natts_pg_rewrite]; + bool replaces[Natts_pg_rewrite]; + NameData rname; + Relation pg_rewrite_desc; + HeapTuple tup, + oldtup; + Oid rewriteObjectId; + ObjectAddress myself, + referenced; + bool is_update = false; + + /* + * Set up *nulls and *values arrays + */ + MemSet(nulls, false, sizeof(nulls)); + + namestrcpy(&rname, rulname); + values[Anum_pg_rewrite_rulename - 1] = NameGetDatum(&rname); + values[Anum_pg_rewrite_ev_class - 1] = ObjectIdGetDatum(eventrel_oid); + values[Anum_pg_rewrite_ev_type - 1] = CharGetDatum(evtype + '0'); + values[Anum_pg_rewrite_ev_enabled - 1] = CharGetDatum(RULE_FIRES_ON_ORIGIN); + values[Anum_pg_rewrite_is_instead - 1] = BoolGetDatum(evinstead); + values[Anum_pg_rewrite_ev_qual - 1] = CStringGetTextDatum(evqual); + values[Anum_pg_rewrite_ev_action - 1] = CStringGetTextDatum(actiontree); + + /* + * Ready to store new pg_rewrite tuple + */ + pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock); + + /* + * Check to see if we are replacing an existing tuple + */ + oldtup = SearchSysCache2(RULERELNAME, + ObjectIdGetDatum(eventrel_oid), + PointerGetDatum(rulname)); + + if (HeapTupleIsValid(oldtup)) + { + if (!replace) + ereport(ERROR, + (errcode(ERRCODE_DUPLICATE_OBJECT), + errmsg("rule \"%s\" for relation \"%s\" already exists", + rulname, get_rel_name(eventrel_oid)))); + + /* + * When replacing, we don't need to replace every attribute + */ + MemSet(replaces, false, sizeof(replaces)); + replaces[Anum_pg_rewrite_ev_type - 1] = true; + replaces[Anum_pg_rewrite_is_instead - 1] = true; + replaces[Anum_pg_rewrite_ev_qual - 1] = true; + replaces[Anum_pg_rewrite_ev_action - 1] = true; + + tup = heap_modify_tuple(oldtup, RelationGetDescr(pg_rewrite_desc), + values, nulls, replaces); + + CatalogTupleUpdate(pg_rewrite_desc, &tup->t_self, tup); + + ReleaseSysCache(oldtup); + + rewriteObjectId = ((Form_pg_rewrite) GETSTRUCT(tup))->oid; + is_update = true; + } + else + { + rewriteObjectId = GetNewOidWithIndex(pg_rewrite_desc, + RewriteOidIndexId, + Anum_pg_rewrite_oid); + values[Anum_pg_rewrite_oid - 1] = ObjectIdGetDatum(rewriteObjectId); + + tup = heap_form_tuple(pg_rewrite_desc->rd_att, values, nulls); + + CatalogTupleInsert(pg_rewrite_desc, tup); + } + + + heap_freetuple(tup); + + /* If replacing, get rid of old dependencies and make new ones */ + if (is_update) + deleteDependencyRecordsFor(RewriteRelationId, rewriteObjectId, false); + + /* + * Install dependency on rule's relation to ensure it will go away on + * relation deletion. If the rule is ON SELECT, make the dependency + * implicit --- this prevents deleting a view's SELECT rule. Other kinds + * of rules can be AUTO. + */ + myself.classId = RewriteRelationId; + myself.objectId = rewriteObjectId; + myself.objectSubId = 0; + + referenced.classId = RelationRelationId; + referenced.objectId = eventrel_oid; + referenced.objectSubId = 0; + + recordDependencyOn(&myself, &referenced, + (evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO); + + /* + * Also install dependencies on objects referenced in action and qual. + */ + recordDependencyOnExpr(&myself, (Node *) action, NIL, + DEPENDENCY_NORMAL); + + if (event_qual != NULL) + { + /* Find query containing OLD/NEW rtable entries */ + Query *qry = linitial_node(Query, action); + + qry = getInsertSelectQuery(qry, NULL); + recordDependencyOnExpr(&myself, event_qual, qry->rtable, + DEPENDENCY_NORMAL); + } + + /* Post creation hook for new rule */ + InvokeObjectPostCreateHook(RewriteRelationId, rewriteObjectId, 0); + + table_close(pg_rewrite_desc, RowExclusiveLock); + + return rewriteObjectId; +} + +/* + * DefineRule + * Execute a CREATE RULE command. + */ +ObjectAddress +DefineRule(RuleStmt *stmt, const char *queryString) +{ + List *actions; + Node *whereClause; + Oid relId; + + /* Parse analysis. */ + transformRuleStmt(stmt, queryString, &actions, &whereClause); + + /* + * Find and lock the relation. Lock level should match + * DefineQueryRewrite. + */ + relId = RangeVarGetRelid(stmt->relation, AccessExclusiveLock, false); + + /* ... and execute */ + return DefineQueryRewrite(stmt->rulename, + relId, + whereClause, + stmt->event, + stmt->instead, + stmt->replace, + actions); +} + + +/* + * DefineQueryRewrite + * Create a rule + * + * This is essentially the same as DefineRule() except that the rule's + * action and qual have already been passed through parse analysis. + */ +ObjectAddress +DefineQueryRewrite(const char *rulename, + Oid event_relid, + Node *event_qual, + CmdType event_type, + bool is_instead, + bool replace, + List *action) +{ + Relation event_relation; + ListCell *l; + Query *query; + bool RelisBecomingView = false; + Oid ruleId = InvalidOid; + ObjectAddress address; + + /* + * If we are installing an ON SELECT rule, we had better grab + * AccessExclusiveLock to ensure no SELECTs are currently running on the + * event relation. For other types of rules, it would be sufficient to + * grab ShareRowExclusiveLock to lock out insert/update/delete actions and + * to ensure that we lock out current CREATE RULE statements; but because + * of race conditions in access to catalog entries, we can't do that yet. + * + * Note that this lock level should match the one used in DefineRule. + */ + event_relation = table_open(event_relid, AccessExclusiveLock); + + /* + * Verify relation is of a type that rules can sensibly be applied to. + * Internal callers can target materialized views, but transformRuleStmt() + * blocks them for users. Don't mention them in the error message. + */ + if (event_relation->rd_rel->relkind != RELKIND_RELATION && + event_relation->rd_rel->relkind != RELKIND_MATVIEW && + event_relation->rd_rel->relkind != RELKIND_VIEW && + event_relation->rd_rel->relkind != RELKIND_PARTITIONED_TABLE) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("relation \"%s\" cannot have rules", + RelationGetRelationName(event_relation)), + errdetail_relkind_not_supported(event_relation->rd_rel->relkind))); + + if (!allowSystemTableMods && IsSystemRelation(event_relation)) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("permission denied: \"%s\" is a system catalog", + RelationGetRelationName(event_relation)))); + + /* + * Check user has permission to apply rules to this relation. + */ + if (!pg_class_ownercheck(event_relid, GetUserId())) + aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(event_relation->rd_rel->relkind), + RelationGetRelationName(event_relation)); + + /* + * No rule actions that modify OLD or NEW + */ + foreach(l, action) + { + query = lfirst_node(Query, l); + if (query->resultRelation == 0) + continue; + /* Don't be fooled by INSERT/SELECT */ + if (query != getInsertSelectQuery(query, NULL)) + continue; + if (query->resultRelation == PRS2_OLD_VARNO) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("rule actions on OLD are not implemented"), + errhint("Use views or triggers instead."))); + if (query->resultRelation == PRS2_NEW_VARNO) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("rule actions on NEW are not implemented"), + errhint("Use triggers instead."))); + } + + if (event_type == CMD_SELECT) + { + /* + * Rules ON SELECT are restricted to view definitions + * + * So there cannot be INSTEAD NOTHING, ... + */ + if (list_length(action) == 0) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("INSTEAD NOTHING rules on SELECT are not implemented"), + errhint("Use views instead."))); + + /* + * ... there cannot be multiple actions, ... + */ + if (list_length(action) > 1) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("multiple actions for rules on SELECT are not implemented"))); + + /* + * ... the one action must be a SELECT, ... + */ + query = linitial_node(Query, action); + if (!is_instead || + query->commandType != CMD_SELECT) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("rules on SELECT must have action INSTEAD SELECT"))); + + /* + * ... it cannot contain data-modifying WITH ... + */ + if (query->hasModifyingCTE) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("rules on SELECT must not contain data-modifying statements in WITH"))); + + /* + * ... there can be no rule qual, ... + */ + if (event_qual != NULL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("event qualifications are not implemented for rules on SELECT"))); + + /* + * ... the targetlist of the SELECT action must exactly match the + * event relation, ... + */ + checkRuleResultList(query->targetList, + RelationGetDescr(event_relation), + true, + event_relation->rd_rel->relkind != + RELKIND_MATVIEW); + + /* + * ... there must not be another ON SELECT rule already ... + */ + if (!replace && event_relation->rd_rules != NULL) + { + int i; + + for (i = 0; i < event_relation->rd_rules->numLocks; i++) + { + RewriteRule *rule; + + rule = event_relation->rd_rules->rules[i]; + if (rule->event == CMD_SELECT) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("\"%s\" is already a view", + RelationGetRelationName(event_relation)))); + } + } + + /* + * ... and finally the rule must be named _RETURN. + */ + if (strcmp(rulename, ViewSelectRuleName) != 0) + { + /* + * In versions before 7.3, the expected name was _RETviewname. For + * backwards compatibility with old pg_dump output, accept that + * and silently change it to _RETURN. Since this is just a quick + * backwards-compatibility hack, limit the number of characters + * checked to a few less than NAMEDATALEN; this saves having to + * worry about where a multibyte character might have gotten + * truncated. + */ + if (strncmp(rulename, "_RET", 4) != 0 || + strncmp(rulename + 4, RelationGetRelationName(event_relation), + NAMEDATALEN - 4 - 4) != 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("view rule for \"%s\" must be named \"%s\"", + RelationGetRelationName(event_relation), + ViewSelectRuleName))); + rulename = pstrdup(ViewSelectRuleName); + } + + /* + * Are we converting a relation to a view? + * + * If so, check that the relation is empty because the storage for the + * relation is going to be deleted. Also insist that the rel not be + * involved in partitioning, nor have any triggers, indexes, child or + * parent tables, RLS policies, or RLS enabled. (Note: some of these + * tests are too strict, because they will reject relations that once + * had such but don't anymore. But we don't really care, because this + * whole business of converting relations to views is just an obsolete + * kluge to allow dump/reload of views that participate in circular + * dependencies.) + */ + if (event_relation->rd_rel->relkind != RELKIND_VIEW && + event_relation->rd_rel->relkind != RELKIND_MATVIEW) + { + TableScanDesc scanDesc; + Snapshot snapshot; + TupleTableSlot *slot; + + if (event_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("cannot convert partitioned table \"%s\" to a view", + RelationGetRelationName(event_relation)))); + + /* only case left: */ + Assert(event_relation->rd_rel->relkind == RELKIND_RELATION); + + if (event_relation->rd_rel->relispartition) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("cannot convert partition \"%s\" to a view", + RelationGetRelationName(event_relation)))); + + snapshot = RegisterSnapshot(GetLatestSnapshot()); + scanDesc = table_beginscan(event_relation, snapshot, 0, NULL); + slot = table_slot_create(event_relation, NULL); + if (table_scan_getnextslot(scanDesc, ForwardScanDirection, slot)) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it is not empty", + RelationGetRelationName(event_relation)))); + ExecDropSingleTupleTableSlot(slot); + table_endscan(scanDesc); + UnregisterSnapshot(snapshot); + + if (event_relation->rd_rel->relhastriggers) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it has triggers", + RelationGetRelationName(event_relation)), + errhint("In particular, the table cannot be involved in any foreign key relationships."))); + + if (event_relation->rd_rel->relhasindex) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it has indexes", + RelationGetRelationName(event_relation)))); + + if (event_relation->rd_rel->relhassubclass) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it has child tables", + RelationGetRelationName(event_relation)))); + + if (has_superclass(RelationGetRelid(event_relation))) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it has parent tables", + RelationGetRelationName(event_relation)))); + + if (event_relation->rd_rel->relrowsecurity) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it has row security enabled", + RelationGetRelationName(event_relation)))); + + if (relation_has_policies(event_relation)) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("could not convert table \"%s\" to a view because it has row security policies", + RelationGetRelationName(event_relation)))); + + RelisBecomingView = true; + } + } + else + { + /* + * For non-SELECT rules, a RETURNING list can appear in at most one of + * the actions ... and there can't be any RETURNING list at all in a + * conditional or non-INSTEAD rule. (Actually, there can be at most + * one RETURNING list across all rules on the same event, but it seems + * best to enforce that at rule expansion time.) If there is a + * RETURNING list, it must match the event relation. + */ + bool haveReturning = false; + + foreach(l, action) + { + query = lfirst_node(Query, l); + + if (!query->returningList) + continue; + if (haveReturning) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot have multiple RETURNING lists in a rule"))); + haveReturning = true; + if (event_qual != NULL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("RETURNING lists are not supported in conditional rules"))); + if (!is_instead) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("RETURNING lists are not supported in non-INSTEAD rules"))); + checkRuleResultList(query->returningList, + RelationGetDescr(event_relation), + false, false); + } + + /* + * And finally, if it's not an ON SELECT rule then it must *not* be + * named _RETURN. This prevents accidentally or maliciously replacing + * a view's ON SELECT rule with some other kind of rule. + */ + if (strcmp(rulename, ViewSelectRuleName) == 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("non-view rule for \"%s\" must not be named \"%s\"", + RelationGetRelationName(event_relation), + ViewSelectRuleName))); + } + + /* + * This rule is allowed - prepare to install it. + */ + + /* discard rule if it's null action and not INSTEAD; it's a no-op */ + if (action != NIL || is_instead) + { + ruleId = InsertRule(rulename, + event_type, + event_relid, + is_instead, + event_qual, + action, + replace); + + /* + * Set pg_class 'relhasrules' field true for event relation. + * + * Important side effect: an SI notice is broadcast to force all + * backends (including me!) to update relcache entries with the new + * rule. + */ + SetRelationRuleStatus(event_relid, true); + } + + /* --------------------------------------------------------------------- + * If the relation is becoming a view: + * - delete the associated storage files + * - get rid of any system attributes in pg_attribute; a view shouldn't + * have any of those + * - remove the toast table; there is no need for it anymore, and its + * presence would make vacuum slightly more complicated + * - set relkind to RELKIND_VIEW, and adjust other pg_class fields + * to be appropriate for a view + * + * NB: we had better have AccessExclusiveLock to do this ... + * --------------------------------------------------------------------- + */ + if (RelisBecomingView) + { + Relation relationRelation; + Oid toastrelid; + HeapTuple classTup; + Form_pg_class classForm; + + relationRelation = table_open(RelationRelationId, RowExclusiveLock); + toastrelid = event_relation->rd_rel->reltoastrelid; + + /* drop storage while table still looks like a table */ + RelationDropStorage(event_relation); + DeleteSystemAttributeTuples(event_relid); + + /* + * Drop the toast table if any. (This won't take care of updating the + * toast fields in the relation's own pg_class entry; we handle that + * below.) + */ + if (OidIsValid(toastrelid)) + { + ObjectAddress toastobject; + + /* + * Delete the dependency of the toast relation on the main + * relation so we can drop the former without dropping the latter. + */ + deleteDependencyRecordsFor(RelationRelationId, toastrelid, + false); + + /* Make deletion of dependency record visible */ + CommandCounterIncrement(); + + /* Now drop toast table, including its index */ + toastobject.classId = RelationRelationId; + toastobject.objectId = toastrelid; + toastobject.objectSubId = 0; + performDeletion(&toastobject, DROP_RESTRICT, + PERFORM_DELETION_INTERNAL); + } + + /* + * SetRelationRuleStatus may have updated the pg_class row, so we must + * advance the command counter before trying to update it again. + */ + CommandCounterIncrement(); + + /* + * Fix pg_class entry to look like a normal view's, including setting + * the correct relkind and removal of reltoastrelid of the toast table + * we potentially removed above. + */ + classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(event_relid)); + if (!HeapTupleIsValid(classTup)) + elog(ERROR, "cache lookup failed for relation %u", event_relid); + classForm = (Form_pg_class) GETSTRUCT(classTup); + + classForm->relam = InvalidOid; + classForm->reltablespace = InvalidOid; + classForm->relpages = 0; + classForm->reltuples = -1; + classForm->relallvisible = 0; + classForm->reltoastrelid = InvalidOid; + classForm->relhasindex = false; + classForm->relkind = RELKIND_VIEW; + classForm->relfrozenxid = InvalidTransactionId; + classForm->relminmxid = InvalidMultiXactId; + classForm->relreplident = REPLICA_IDENTITY_NOTHING; + + CatalogTupleUpdate(relationRelation, &classTup->t_self, classTup); + + heap_freetuple(classTup); + table_close(relationRelation, RowExclusiveLock); + } + + ObjectAddressSet(address, RewriteRelationId, ruleId); + + /* Close rel, but keep lock till commit... */ + table_close(event_relation, NoLock); + + return address; +} + +/* + * checkRuleResultList + * Verify that targetList produces output compatible with a tupledesc + * + * The targetList might be either a SELECT targetlist, or a RETURNING list; + * isSelect tells which. This is used for choosing error messages. + * + * A SELECT targetlist may optionally require that column names match. + */ +static void +checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect, + bool requireColumnNameMatch) +{ + ListCell *tllist; + int i; + + /* Only a SELECT may require a column name match. */ + Assert(isSelect || !requireColumnNameMatch); + + i = 0; + foreach(tllist, targetList) + { + TargetEntry *tle = (TargetEntry *) lfirst(tllist); + Oid tletypid; + int32 tletypmod; + Form_pg_attribute attr; + char *attname; + + /* resjunk entries may be ignored */ + if (tle->resjunk) + continue; + i++; + if (i > resultDesc->natts) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + isSelect ? + errmsg("SELECT rule's target list has too many entries") : + errmsg("RETURNING list has too many entries"))); + + attr = TupleDescAttr(resultDesc, i - 1); + attname = NameStr(attr->attname); + + /* + * Disallow dropped columns in the relation. This is not really + * expected to happen when creating an ON SELECT rule. It'd be + * possible if someone tried to convert a relation with dropped + * columns to a view, but the only case we care about supporting + * table-to-view conversion for is pg_dump, and pg_dump won't do that. + * + * Unfortunately, the situation is also possible when adding a rule + * with RETURNING to a regular table, and rejecting that case is + * altogether more annoying. In principle we could support it by + * modifying the targetlist to include dummy NULL columns + * corresponding to the dropped columns in the tupdesc. However, + * places like ruleutils.c would have to be fixed to not process such + * entries, and that would take an uncertain and possibly rather large + * amount of work. (Note we could not dodge that by marking the dummy + * columns resjunk, since it's precisely the non-resjunk tlist columns + * that are expected to correspond to table columns.) + */ + if (attr->attisdropped) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + isSelect ? + errmsg("cannot convert relation containing dropped columns to view") : + errmsg("cannot create a RETURNING list for a relation containing dropped columns"))); + + /* Check name match if required; no need for two error texts here */ + if (requireColumnNameMatch && strcmp(tle->resname, attname) != 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("SELECT rule's target entry %d has different column name from column \"%s\"", + i, attname), + errdetail("SELECT target entry is named \"%s\".", + tle->resname))); + + /* Check type match. */ + tletypid = exprType((Node *) tle->expr); + if (attr->atttypid != tletypid) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + isSelect ? + errmsg("SELECT rule's target entry %d has different type from column \"%s\"", + i, attname) : + errmsg("RETURNING list's entry %d has different type from column \"%s\"", + i, attname), + isSelect ? + errdetail("SELECT target entry has type %s, but column has type %s.", + format_type_be(tletypid), + format_type_be(attr->atttypid)) : + errdetail("RETURNING list entry has type %s, but column has type %s.", + format_type_be(tletypid), + format_type_be(attr->atttypid)))); + + /* + * Allow typmods to be different only if one of them is -1, ie, + * "unspecified". This is necessary for cases like "numeric", where + * the table will have a filled-in default length but the select + * rule's expression will probably have typmod = -1. + */ + tletypmod = exprTypmod((Node *) tle->expr); + if (attr->atttypmod != tletypmod && + attr->atttypmod != -1 && tletypmod != -1) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + isSelect ? + errmsg("SELECT rule's target entry %d has different size from column \"%s\"", + i, attname) : + errmsg("RETURNING list's entry %d has different size from column \"%s\"", + i, attname), + isSelect ? + errdetail("SELECT target entry has type %s, but column has type %s.", + format_type_with_typemod(tletypid, tletypmod), + format_type_with_typemod(attr->atttypid, + attr->atttypmod)) : + errdetail("RETURNING list entry has type %s, but column has type %s.", + format_type_with_typemod(tletypid, tletypmod), + format_type_with_typemod(attr->atttypid, + attr->atttypmod)))); + } + + if (i != resultDesc->natts) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + isSelect ? + errmsg("SELECT rule's target list has too few entries") : + errmsg("RETURNING list has too few entries"))); +} + +/* + * setRuleCheckAsUser + * Recursively scan a query or expression tree and set the checkAsUser + * field to the given userid in all rtable entries. + * + * Note: for a view (ON SELECT rule), the checkAsUser field of the OLD + * RTE entry will be overridden when the view rule is expanded, and the + * checkAsUser field of the NEW entry is irrelevant because that entry's + * requiredPerms bits will always be zero. However, for other types of rules + * it's important to set these fields to match the rule owner. So we just set + * them always. + */ +void +setRuleCheckAsUser(Node *node, Oid userid) +{ + (void) setRuleCheckAsUser_walker(node, &userid); +} + +static bool +setRuleCheckAsUser_walker(Node *node, Oid *context) +{ + if (node == NULL) + return false; + if (IsA(node, Query)) + { + setRuleCheckAsUser_Query((Query *) node, *context); + return false; + } + return expression_tree_walker(node, setRuleCheckAsUser_walker, + (void *) context); +} + +static void +setRuleCheckAsUser_Query(Query *qry, Oid userid) +{ + ListCell *l; + + /* Set all the RTEs in this query node */ + foreach(l, qry->rtable) + { + RangeTblEntry *rte = (RangeTblEntry *) lfirst(l); + + if (rte->rtekind == RTE_SUBQUERY) + { + /* Recurse into subquery in FROM */ + setRuleCheckAsUser_Query(rte->subquery, userid); + } + else + rte->checkAsUser = userid; + } + + /* Recurse into subquery-in-WITH */ + foreach(l, qry->cteList) + { + CommonTableExpr *cte = (CommonTableExpr *) lfirst(l); + + setRuleCheckAsUser_Query(castNode(Query, cte->ctequery), userid); + } + + /* If there are sublinks, search for them and process their RTEs */ + if (qry->hasSubLinks) + query_tree_walker(qry, setRuleCheckAsUser_walker, (void *) &userid, + QTW_IGNORE_RC_SUBQUERIES); +} + + +/* + * Change the firing semantics of an existing rule. + */ +void +EnableDisableRule(Relation rel, const char *rulename, + char fires_when) +{ + Relation pg_rewrite_desc; + Oid owningRel = RelationGetRelid(rel); + Oid eventRelationOid; + HeapTuple ruletup; + Form_pg_rewrite ruleform; + bool changed = false; + + /* + * Find the rule tuple to change. + */ + pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock); + ruletup = SearchSysCacheCopy2(RULERELNAME, + ObjectIdGetDatum(owningRel), + PointerGetDatum(rulename)); + if (!HeapTupleIsValid(ruletup)) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("rule \"%s\" for relation \"%s\" does not exist", + rulename, get_rel_name(owningRel)))); + + ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup); + + /* + * Verify that the user has appropriate permissions. + */ + eventRelationOid = ruleform->ev_class; + Assert(eventRelationOid == owningRel); + if (!pg_class_ownercheck(eventRelationOid, GetUserId())) + aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(eventRelationOid)), + get_rel_name(eventRelationOid)); + + /* + * Change ev_enabled if it is different from the desired new state. + */ + if (DatumGetChar(ruleform->ev_enabled) != + fires_when) + { + ruleform->ev_enabled = CharGetDatum(fires_when); + CatalogTupleUpdate(pg_rewrite_desc, &ruletup->t_self, ruletup); + + changed = true; + } + + InvokeObjectPostAlterHook(RewriteRelationId, ruleform->oid, 0); + + heap_freetuple(ruletup); + table_close(pg_rewrite_desc, RowExclusiveLock); + + /* + * If we changed anything, broadcast a SI inval message to force each + * backend (including our own!) to rebuild relation's relcache entry. + * Otherwise they will fail to apply the change promptly. + */ + if (changed) + CacheInvalidateRelcache(rel); +} + + +/* + * Perform permissions and integrity checks before acquiring a relation lock. + */ +static void +RangeVarCallbackForRenameRule(const RangeVar *rv, Oid relid, Oid oldrelid, + void *arg) +{ + HeapTuple tuple; + Form_pg_class form; + + tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid)); + if (!HeapTupleIsValid(tuple)) + return; /* concurrently dropped */ + form = (Form_pg_class) GETSTRUCT(tuple); + + /* only tables and views can have rules */ + if (form->relkind != RELKIND_RELATION && + form->relkind != RELKIND_VIEW && + form->relkind != RELKIND_PARTITIONED_TABLE) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("relation \"%s\" cannot have rules", rv->relname), + errdetail_relkind_not_supported(form->relkind))); + + if (!allowSystemTableMods && IsSystemClass(relid, form)) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("permission denied: \"%s\" is a system catalog", + rv->relname))); + + /* you must own the table to rename one of its rules */ + if (!pg_class_ownercheck(relid, GetUserId())) + aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(relid)), rv->relname); + + ReleaseSysCache(tuple); +} + +/* + * Rename an existing rewrite rule. + */ +ObjectAddress +RenameRewriteRule(RangeVar *relation, const char *oldName, + const char *newName) +{ + Oid relid; + Relation targetrel; + Relation pg_rewrite_desc; + HeapTuple ruletup; + Form_pg_rewrite ruleform; + Oid ruleOid; + ObjectAddress address; + + /* + * Look up name, check permissions, and acquire lock (which we will NOT + * release until end of transaction). + */ + relid = RangeVarGetRelidExtended(relation, AccessExclusiveLock, + 0, + RangeVarCallbackForRenameRule, + NULL); + + /* Have lock already, so just need to build relcache entry. */ + targetrel = relation_open(relid, NoLock); + + /* Prepare to modify pg_rewrite */ + pg_rewrite_desc = table_open(RewriteRelationId, RowExclusiveLock); + + /* Fetch the rule's entry (it had better exist) */ + ruletup = SearchSysCacheCopy2(RULERELNAME, + ObjectIdGetDatum(relid), + PointerGetDatum(oldName)); + if (!HeapTupleIsValid(ruletup)) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("rule \"%s\" for relation \"%s\" does not exist", + oldName, RelationGetRelationName(targetrel)))); + ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup); + ruleOid = ruleform->oid; + + /* rule with the new name should not already exist */ + if (IsDefinedRewriteRule(relid, newName)) + ereport(ERROR, + (errcode(ERRCODE_DUPLICATE_OBJECT), + errmsg("rule \"%s\" for relation \"%s\" already exists", + newName, RelationGetRelationName(targetrel)))); + + /* + * We disallow renaming ON SELECT rules, because they should always be + * named "_RETURN". + */ + if (ruleform->ev_type == CMD_SELECT + '0') + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("renaming an ON SELECT rule is not allowed"))); + + /* OK, do the update */ + namestrcpy(&(ruleform->rulename), newName); + + CatalogTupleUpdate(pg_rewrite_desc, &ruletup->t_self, ruletup); + + InvokeObjectPostAlterHook(RewriteRelationId, ruleOid, 0); + + heap_freetuple(ruletup); + table_close(pg_rewrite_desc, RowExclusiveLock); + + /* + * Invalidate relation's relcache entry so that other backends (and this + * one too!) are sent SI message to make them rebuild relcache entries. + * (Ideally this should happen automatically...) + */ + CacheInvalidateRelcache(targetrel); + + ObjectAddressSet(address, RewriteRelationId, ruleOid); + + /* + * Close rel, but keep exclusive lock! + */ + relation_close(targetrel, NoLock); + + return address; +} |