rewriteDefine.h File Reference

#include "catalog/objectaddress.h"
#include "nodes/parsenodes.h"
#include "utils/relcache.h"

Include dependency graph for rewriteDefine.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	RULE_FIRES_ON_ORIGIN   'O'
#define	RULE_FIRES_ALWAYS   'A'
#define	RULE_FIRES_ON_REPLICA   'R'
#define	RULE_DISABLED   'D'

Functions
ObjectAddress	DefineRule (RuleStmt *stmt, const char *queryString)
ObjectAddress	DefineQueryRewrite (const char *rulename, Oid event_relid, Node *event_qual, CmdType event_type, bool is_instead, bool replace, List *action)
ObjectAddress	RenameRewriteRule (RangeVar *relation, const char *oldName, const char *newName)
void	setRuleCheckAsUser (Node *node, Oid userid)
void	EnableDisableRule (Relation rel, const char *rulename, char fires_when)

Macro Definition Documentation

RULE_DISABLED

#define RULE_DISABLED   'D'

Definition at line 24 of file rewriteDefine.h.

RULE_FIRES_ALWAYS

#define RULE_FIRES_ALWAYS   'A'

Definition at line 22 of file rewriteDefine.h.

RULE_FIRES_ON_ORIGIN

#define RULE_FIRES_ON_ORIGIN   'O'

Definition at line 21 of file rewriteDefine.h.

RULE_FIRES_ON_REPLICA

#define RULE_FIRES_ON_REPLICA   'R'

Definition at line 23 of file rewriteDefine.h.

Function Documentation

DefineQueryRewrite()

ObjectAddress DefineQueryRewrite ( const char *  rulename, Oid  event_relid, Node *  event_qual, CmdType  event_type, bool  is_instead, bool  replace, List *  action  )

extern

Definition at line 224 of file rewriteDefine.c.

{
    Relation    event_relation;
    ListCell   *l;
    Query      *query;
    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 (!object_ownercheck(RelationRelationId, 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 this had better be a view, ...
         */
        if (event_relation->rd_rel->relkind != RELKIND_VIEW &&
            event_relation->rd_rel->relkind != RELKIND_MATVIEW)
            ereport(ERROR,
                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                     errmsg("relation \"%s\" cannot have ON SELECT rules",
                            RelationGetRelationName(event_relation)),
                     errdetail_relkind_not_supported(event_relation->rd_rel->relkind)));
 
        /*
         * ... there cannot be INSTEAD NOTHING, ...
         */
        if (action == NIL)
            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);
        }
    }
    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);
    }
 
    ObjectAddressSet(address, RewriteRelationId, ruleId);
 
    /* Close rel, but keep lock till commit... */
    table_close(event_relation, NoLock);
 
    return address;
}

References AccessExclusiveLock, aclcheck_error(), ACLCHECK_NOT_OWNER, allowSystemTableMods, checkRuleResultList(), CMD_SELECT, Query::commandType, ereport, errcode(), errdetail_relkind_not_supported(), errhint(), errmsg(), ERROR, fb(), get_relkind_objtype(), getInsertSelectQuery(), GetUserId(), i, InsertRule(), InvalidOid, IsSystemRelation(), lfirst_node, linitial_node, list_length(), NAMEDATALEN, NIL, NoLock, object_ownercheck(), ObjectAddressSet, PRS2_NEW_VARNO, PRS2_OLD_VARNO, pstrdup(), RelationGetDescr, RelationGetRelationName, Query::returningList, SetRelationRuleStatus(), table_close(), table_open(), Query::targetList, and ViewSelectRuleName.

Referenced by DefineRule(), and DefineViewRules().

DefineRule()

ObjectAddress DefineRule ( RuleStmt *  stmt, const char *  queryString  )

extern

Definition at line 190 of file rewriteDefine.c.

{
    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);
}

References AccessExclusiveLock, DefineQueryRewrite(), RangeVarGetRelid, stmt, and transformRuleStmt().

Referenced by ProcessUtilitySlow().

EnableDisableRule()

void EnableDisableRule ( Relation  rel, const char *  rulename, char  fires_when  )

extern

Definition at line 691 of file rewriteDefine.c.

{
    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 (!object_ownercheck(RelationRelationId, 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 (ruleform->ev_enabled != fires_when)
    {
        ruleform->ev_enabled = 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);
}

References aclcheck_error(), ACLCHECK_NOT_OWNER, Assert, CacheInvalidateRelcache(), CatalogTupleUpdate(), ereport, errcode(), errmsg(), ERROR, fb(), get_rel_name(), get_rel_relkind(), get_relkind_objtype(), GETSTRUCT(), GetUserId(), heap_freetuple(), HeapTupleIsValid, InvokeObjectPostAlterHook, object_ownercheck(), ObjectIdGetDatum(), PointerGetDatum(), RelationGetRelid, RowExclusiveLock, SearchSysCacheCopy2, table_close(), and table_open().

Referenced by ATExecEnableDisableRule().

RenameRewriteRule()

ObjectAddress RenameRewriteRule ( RangeVar *  relation, const char *  oldName, const char *  newName  )

extern

Definition at line 792 of file rewriteDefine.c.

{
    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;
}

References AccessExclusiveLock, CacheInvalidateRelcache(), CatalogTupleUpdate(), CMD_SELECT, ereport, errcode(), ERRCODE_DUPLICATE_OBJECT, errmsg(), ERROR, fb(), GETSTRUCT(), heap_freetuple(), HeapTupleIsValid, InvokeObjectPostAlterHook, IsDefinedRewriteRule(), namestrcpy(), NoLock, ObjectAddressSet, ObjectIdGetDatum(), PointerGetDatum(), RangeVarCallbackForRenameRule(), RangeVarGetRelidExtended(), relation_close(), relation_open(), RelationGetRelationName, RowExclusiveLock, SearchSysCacheCopy2, table_close(), and table_open().

Referenced by ExecRenameStmt().

setRuleCheckAsUser()

void setRuleCheckAsUser ( Node *  node, Oid  userid  )

extern

Definition at line 631 of file rewriteDefine.c.

{
    (void) setRuleCheckAsUser_walker(node, &userid);
}

References fb(), and setRuleCheckAsUser_walker().

Referenced by get_row_security_policies(), and RelationBuildRuleLock().