check_authorization()

Datum check_authorization

(

PG_FUNCTION_ARGS

)

Definition at line 49 of file long_xact.c.

{
        TriggerData *trigdata = (TriggerData *) fcinfo->context;
        char *colname;
        HeapTuple rettuple_ok;
        HeapTuple rettuple_fail;
        TupleDesc tupdesc;
        int SPIcode;
        char query[1024];
        const char *pk_id = NULL;
        SPITupleTable *tuptable;
        HeapTuple tuple;
        char *lockcode;
        char *authtable = "authorization_table";
        const char *op;
        char err_msg[256];
 
 
        /* Make sure trigdata is pointing at what I expect */
        if ( ! CALLED_AS_TRIGGER(fcinfo) )
        {
                elog(ERROR,"check_authorization: not fired by trigger manager");
        }
 
        if ( ! TRIGGER_FIRED_BEFORE(trigdata->tg_event) )
        {
                elog(ERROR,"check_authorization: not fired *before* event");
        }
 
        if ( TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event) )
        {
                rettuple_ok = trigdata->tg_newtuple;
                rettuple_fail = NULL;
                op = "UPDATE";
        }
        else if ( TRIGGER_FIRED_BY_DELETE(trigdata->tg_event) )
        {
                rettuple_ok = trigdata->tg_trigtuple;
                rettuple_fail = NULL;
                op = "DELETE";
        }
        else
        {
                elog(ERROR,"check_authorization: not fired by update or delete");
                PG_RETURN_NULL();
        }
 
 
        tupdesc = trigdata->tg_relation->rd_att;
 
        /* Connect to SPI manager */
        SPIcode = SPI_connect();
 
        if (SPIcode  != SPI_OK_CONNECT)
        {
                elog(ERROR,"check_authorization: could not connect to SPI");
                PG_RETURN_NULL() ;
        }
 
        colname  = trigdata->tg_trigger->tgargs[0];
        pk_id = SPI_getvalue(trigdata->tg_trigtuple, tupdesc,
                             SPI_fnumber(tupdesc, colname));
 
        POSTGIS_DEBUG(3, "check_authorization called");
 
        snprintf(query, sizeof(query), "SELECT authid FROM \"%s\" WHERE expires >= now() AND toid = '%d' AND rid = '%s'", authtable, trigdata->tg_relation->rd_id, pk_id);
 
        POSTGIS_DEBUGF(3 ,"about to execute :%s", query);
 
        SPIcode = SPI_exec(query,0);
        if (SPIcode !=SPI_OK_SELECT )
                elog(ERROR,"couldnt execute to test for lock :%s",query);
 
        if (!SPI_processed )
        {
                POSTGIS_DEBUGF(3, "there is NO lock on row '%s'", pk_id);
 
                SPI_finish();
                return PointerGetDatum(rettuple_ok);
        }
 
        /* there is a lock - check to see if I have rights to it! */
 
        tuptable = SPI_tuptable;
        tupdesc = tuptable->tupdesc;
        tuple = tuptable->vals[0];
        lockcode = SPI_getvalue(tuple, tupdesc, 1);
 
        POSTGIS_DEBUGF(3, "there is a lock on row '%s' (auth: '%s').", pk_id, lockcode);
 
        /*
         * check to see if temp_lock_have_table table exists
         * (it might not exist if they own no locks)
         */
        snprintf(query, sizeof(query), "SELECT * FROM pg_class WHERE relname = 'temp_lock_have_table'");
        SPIcode = SPI_exec(query,0);
        if (SPIcode != SPI_OK_SELECT )
                elog(ERROR,"couldnt execute to test for lockkey temp table :%s",query);
        if (SPI_processed==0)
        {
                goto fail;
        }
 
        snprintf(query, sizeof(query), "SELECT * FROM temp_lock_have_table WHERE xideq( transid, getTransactionID() ) AND lockcode ='%s'", lockcode);
 
        POSTGIS_DEBUGF(3, "about to execute :%s", query);
 
        SPIcode = SPI_exec(query,0);
        if (SPIcode != SPI_OK_SELECT )
                elog(ERROR, "couldnt execute to test for lock acquire: %s", query);
 
        if (SPI_processed >0)
        {
                POSTGIS_DEBUG(3, "I own the lock - I can modify the row");
 
                SPI_finish();
                return PointerGetDatum(rettuple_ok);
        }
 
fail:
 
        snprintf(err_msg, sizeof(err_msg), "%s where \"%s\" = '%s' requires authorization '%s'",
                 op, colname, pk_id, lockcode);
        err_msg[sizeof(err_msg)-1] = '\0';
 
#ifdef ABORT_ON_AUTH_FAILURE
        elog(ERROR, "%s", err_msg);
#else
        elog(NOTICE, "%s", err_msg);
#endif
 
        SPI_finish();
        return PointerGetDatum(rettuple_fail);
 
 
}