ipc_perm
ipcperm(struct ucred *cred, struct ipc_perm *perm, int mode)
int ipcperm(struct ucred *, struct ipc_perm *, int);
struct ipc_perm msg_perm; /* msg queue permission bits */
struct ipc_perm sem_perm; /* operation permission struct */
struct ipc_perm shm_perm; /* operation permission structure */