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Sourcecode: postgresql-8.4 version File versions

superuser.c

/*-------------------------------------------------------------------------
 *
 * superuser.c
 *      The superuser() function.  Determines if user has superuser privilege.
 *
 * All code should use either of these two functions to find out
 * whether a given user is a superuser, rather than examining
 * pg_authid.rolsuper directly, so that the escape hatch built in for
 * the single-user case works.
 *
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *      $PostgreSQL$
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "catalog/pg_authid.h"
#include "utils/inval.h"
#include "utils/syscache.h"
#include "miscadmin.h"


/*
 * In common cases the same roleid (ie, the session or current ID) will
 * be queried repeatedly.  So we maintain a simple one-entry cache for
 * the status of the last requested roleid.  The cache can be flushed
 * at need by watching for cache update events on pg_authid.
 */
static Oid  last_roleid = InvalidOid;     /* InvalidOid == cache not valid */
static bool last_roleid_is_super = false;
static bool roleid_callback_registered = false;

static void RoleidCallback(Datum arg, int cacheid, ItemPointer tuplePtr);


/*
 * The Postgres user running this command has Postgres superuser privileges
 */
bool
superuser(void)
{
      return superuser_arg(GetUserId());
}


/*
 * The specified role has Postgres superuser privileges
 */
bool
superuser_arg(Oid roleid)
{
      bool        result;
      HeapTuple   rtup;

      /* Quick out for cache hit */
      if (OidIsValid(last_roleid) && last_roleid == roleid)
            return last_roleid_is_super;

      /* Special escape path in case you deleted all your users. */
      if (!IsUnderPostmaster && roleid == BOOTSTRAP_SUPERUSERID)
            return true;

      /* OK, look up the information in pg_authid */
      rtup = SearchSysCache(AUTHOID,
                                      ObjectIdGetDatum(roleid),
                                      0, 0, 0);
      if (HeapTupleIsValid(rtup))
      {
            result = ((Form_pg_authid) GETSTRUCT(rtup))->rolsuper;
            ReleaseSysCache(rtup);
      }
      else
      {
            /* Report "not superuser" for invalid roleids */
            result = false;
      }

      /* If first time through, set up callback for cache flushes */
      if (!roleid_callback_registered)
      {
            CacheRegisterSyscacheCallback(AUTHOID,
                                                        RoleidCallback,
                                                        (Datum) 0);
            roleid_callback_registered = true;
      }

      /* Cache the result for next time */
      last_roleid = roleid;
      last_roleid_is_super = result;

      return result;
}

/*
 * UseridCallback
 *          Syscache inval callback function
 */
static void
RoleidCallback(Datum arg, int cacheid, ItemPointer tuplePtr)
{
      /* Invalidate our local cache in case role's superuserness changed */
      last_roleid = InvalidOid;
}

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