src/backend/catalog/pg_parameter_acl.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_parameter_acl.c
   4  *        routines to support manipulation of the pg_parameter_acl relation
   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/catalog/pg_parameter_acl.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/table.h"
  18 #include "catalog/catalog.h"
  19 #include "catalog/indexing.h"
  20 #include "catalog/pg_parameter_acl.h"
  21 #include "utils/builtins.h"
  22 #include "utils/guc.h"
  23 #include "utils/rel.h"
  24 #include "utils/syscache.h"
  25
  26
  27 /*
  28  * ParameterAclLookup - Given a configuration parameter name,
  29  * look up the associated configuration parameter ACL's OID.
  30  *
  31  * If missing_ok is false, throw an error if ACL entry not found.  If
  32  * true, just return InvalidOid.
  33  */
  34 Oid
  35 ParameterAclLookup(const char *parameter, bool missing_ok)
  36 {
  37         Oid                     oid;
  38         char       *parname;
  39
  40         /* Convert name to the form it should have in pg_parameter_acl... */
  41         parname = convert_GUC_name_for_parameter_acl(parameter);
  42
  43         /* ... and look it up */
  44         oid = GetSysCacheOid1(PARAMETERACLNAME, Anum_pg_parameter_acl_oid,
  45                                                   PointerGetDatum(cstring_to_text(parname)));
  46
  47         if (!OidIsValid(oid) && !missing_ok)
  48                 ereport(ERROR,
  49                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
  50                                  errmsg("parameter ACL \"%s\" does not exist", parameter)));
  51
  52         pfree(parname);
  53
  54         return oid;
  55 }
  56
  57 /*
  58  * ParameterAclCreate
  59  *
  60  * Add a new tuple to pg_parameter_acl.
  61  *
  62  * parameter: the parameter name to create an entry for.
  63  * Caller should have verified that there's no such entry already.
  64  *
  65  * Returns the new entry's OID.
  66  */
  67 Oid
  68 ParameterAclCreate(const char *parameter)
  69 {
  70         Oid                     parameterId;
  71         char       *parname;
  72         Relation        rel;
  73         TupleDesc       tupDesc;
  74         HeapTuple       tuple;
  75         Datum           values[Natts_pg_parameter_acl] = {0};
  76         bool            nulls[Natts_pg_parameter_acl] = {0};
  77
  78         /*
  79          * To prevent cluttering pg_parameter_acl with useless entries, insist
  80          * that the name be valid.
  81          */
  82         check_GUC_name_for_parameter_acl(parameter);
  83
  84         /* Convert name to the form it should have in pg_parameter_acl. */
  85         parname = convert_GUC_name_for_parameter_acl(parameter);
  86
  87         /*
  88          * Create and insert a new record containing a null ACL.
  89          *
  90          * We don't take a strong enough lock to prevent concurrent insertions,
  91          * relying instead on the unique index.
  92          */
  93         rel = table_open(ParameterAclRelationId, RowExclusiveLock);
  94         tupDesc = RelationGetDescr(rel);
  95         parameterId = GetNewOidWithIndex(rel,
  96                                                                          ParameterAclOidIndexId,
  97                                                                          Anum_pg_parameter_acl_oid);
  98         values[Anum_pg_parameter_acl_oid - 1] = ObjectIdGetDatum(parameterId);
  99         values[Anum_pg_parameter_acl_parname - 1] =
 100                 PointerGetDatum(cstring_to_text(parname));
 101         nulls[Anum_pg_parameter_acl_paracl - 1] = true;
 102         tuple = heap_form_tuple(tupDesc, values, nulls);
 103         CatalogTupleInsert(rel, tuple);
 104
 105         /* Close pg_parameter_acl, but keep lock till commit. */
 106         heap_freetuple(tuple);
 107         table_close(rel, NoLock);
 108
 109         return parameterId;
 110 }