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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:46:48 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:46:48 +0000
commit311bcfc6b3acdd6fd152798c7f287ddf74fa2a98 (patch)
tree0ec307299b1dada3701e42f4ca6eda57d708261e /src/backend/rewrite/rewriteDefine.c
parentInitial commit. (diff)
downloadpostgresql-15-upstream.tar.xz
postgresql-15-upstream.zip
Adding upstream version 15.4.upstream/15.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/backend/rewrite/rewriteDefine.c')
-rw-r--r--src/backend/rewrite/rewriteDefine.c1050
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;
+}