pg_parameter_acl.c

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/*-------------------------------------------------------------------------
 *
 * pg_parameter_acl.c
 *    routines to support manipulation of the pg_parameter_acl relation
 *
 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/catalog/pg_parameter_acl.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "access/table.h"
#include "catalog/catalog.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_parameter_acl.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/pg_locale.h"
#include "utils/rel.h"
#include "utils/syscache.h"
 
 
/*
 * ParameterAclLookup - Given a configuration parameter name,
 * look up the associated configuration parameter ACL's OID.
 *
 * If missing_ok is false, throw an error if ACL entry not found.  If
 * true, just return InvalidOid.
 */
Oid
ParameterAclLookup(const char *parameter, bool missing_ok)
{
    Oid         oid;
    char       *parname;
 
    /* Convert name to the form it should have in pg_parameter_acl... */
    parname = convert_GUC_name_for_parameter_acl(parameter);
 
    /* ... and look it up */
    oid = GetSysCacheOid1(PARAMETERACLNAME, Anum_pg_parameter_acl_oid,
                          PointerGetDatum(cstring_to_text(parname)));
 
    if (!OidIsValid(oid) && !missing_ok)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("parameter ACL \"%s\" does not exist", parameter)));
 
    pfree(parname);
 
    return oid;
}
 
/*
 * ParameterAclCreate
 *
 * Add a new tuple to pg_parameter_acl.
 *
 * parameter: the parameter name to create an entry for.
 * Caller should have verified that there's no such entry already.
 *
 * Returns the new entry's OID.
 */
Oid
ParameterAclCreate(const char *parameter)
{
    Oid         parameterId;
    char       *parname;
    Relation    rel;
    TupleDesc   tupDesc;
    HeapTuple   tuple;
    Datum       values[Natts_pg_parameter_acl] = {0};
    bool        nulls[Natts_pg_parameter_acl] = {0};
 
    /*
     * To prevent cluttering pg_parameter_acl with useless entries, insist
     * that the name be valid.
     */
    check_GUC_name_for_parameter_acl(parameter);
 
    /* Convert name to the form it should have in pg_parameter_acl. */
    parname = convert_GUC_name_for_parameter_acl(parameter);
 
    /*
     * Create and insert a new record containing a null ACL.
     *
     * We don't take a strong enough lock to prevent concurrent insertions,
     * relying instead on the unique index.
     */
    rel = table_open(ParameterAclRelationId, RowExclusiveLock);
    tupDesc = RelationGetDescr(rel);
    parameterId = GetNewOidWithIndex(rel,
                                     ParameterAclOidIndexId,
                                     Anum_pg_parameter_acl_oid);
    values[Anum_pg_parameter_acl_oid - 1] = ObjectIdGetDatum(parameterId);
    values[Anum_pg_parameter_acl_parname - 1] =
        PointerGetDatum(cstring_to_text(parname));
    nulls[Anum_pg_parameter_acl_paracl - 1] = true;
    tuple = heap_form_tuple(tupDesc, values, nulls);
    CatalogTupleInsert(rel, tuple);
 
    /* Close pg_parameter_acl, but keep lock till commit. */
    heap_freetuple(tuple);
    table_close(rel, NoLock);
 
    return parameterId;
}