SHM_RDONLY
(SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0)
shm_stat = (struct ub_shm_stat_info*)shmat(id_ctl, NULL, SHM_RDONLY);
stats = (struct ub_stats_info*)shmat(id_arr, NULL, SHM_RDONLY);