granicus.if.org Git - postgresql/blob - src/backend/utils/misc/superuser.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * superuser.c
   4  *        The superuser() function.  Determines if user has superuser privilege.
   5  *        Also, a function to check for the owner (datdba) of a database.
   6  *
   7  *
   8  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
   9  * Portions Copyright (c) 1994, Regents of the University of California
  10  *
  11  *
  12  * IDENTIFICATION
  13  *        $Header: /cvsroot/pgsql/src/backend/utils/misc/superuser.c,v 1.22 2002/05/20 23:51:43 tgl Exp $
  14  *
  15  *-------------------------------------------------------------------------
  16  */
  17 #include "postgres.h"
  18
  19 #include "access/heapam.h"
  20 #include "catalog/catname.h"
  21 #include "catalog/pg_database.h"
  22 #include "catalog/pg_shadow.h"
  23 #include "utils/syscache.h"
  24 #include "miscadmin.h"
  25 #include "utils/fmgroids.h"
  26
  27
  28 /*
  29  * The Postgres user running this command has Postgres superuser privileges
  30  *
  31  * All code should use either of these two functions to find out
  32  * whether a given user is a superuser, rather than evaluating
  33  * pg_shadow.usesuper directly, so that the escape hatch built in for
  34  * the single-user case works.
  35  */
  36 bool
  37 superuser(void)
  38 {
  39         return superuser_arg(GetUserId());
  40 }
  41
  42
  43 bool
  44 superuser_arg(Oid userid)
  45 {
  46         bool            result = false;
  47         HeapTuple       utup;
  48
  49         /* Special escape path in case you deleted all your users. */
  50         if (!IsUnderPostmaster && userid == BOOTSTRAP_USESYSID)
  51                 return true;
  52
  53         utup = SearchSysCache(SHADOWSYSID,
  54                                                   ObjectIdGetDatum(userid),
  55                                                   0, 0, 0);
  56         if (HeapTupleIsValid(utup))
  57         {
  58                 result = ((Form_pg_shadow) GETSTRUCT(utup))->usesuper;
  59                 ReleaseSysCache(utup);
  60         }
  61         return result;
  62 }
  63
  64
  65 /*
  66  * The Postgres user running this command is the owner of the specified
  67  * database.
  68  */
  69 bool
  70 is_dbadmin(Oid dbid)
  71 {
  72         Relation        pg_database;
  73         ScanKeyData entry[1];
  74         HeapScanDesc scan;
  75         HeapTuple       dbtuple;
  76         int32           dba;
  77
  78         /* There's no syscache for pg_database, so must look the hard way */
  79         pg_database = heap_openr(DatabaseRelationName, AccessShareLock);
  80         ScanKeyEntryInitialize(&entry[0], 0x0,
  81                                                    ObjectIdAttributeNumber, F_OIDEQ,
  82                                                    ObjectIdGetDatum(dbid));
  83         scan = heap_beginscan(pg_database, SnapshotNow, 1, entry);
  84         dbtuple = heap_getnext(scan, ForwardScanDirection);
  85         if (!HeapTupleIsValid(dbtuple))
  86                 elog(ERROR, "database %u does not exist", dbid);
  87         dba = ((Form_pg_database) GETSTRUCT(dbtuple))->datdba;
  88         heap_endscan(scan);
  89         heap_close(pg_database, AccessShareLock);
  90
  91         /* XXX some confusion about whether userids are OID or int4 ... */
  92         return (GetUserId() == (Oid) dba);
  93 }