SELECT s.SID,
       s.SERIAL#,
       pa.VALUE || '/' || lower(sys_context('userenv', 'instance_name')) ||
       '_ora_' || p.SPID || '.trc' AS TRACE_FILE
FROM V$SESSION s, V$PROCESS p, V$paRAMETER pa
WHERE pa.NAME = 'user_dump_dest'
  AND s.paDDR = p.ADDR
  AND s.AUDSID = sys_context('USERENV', 'SESSIONID');