Function semvalid

freebsd/kern/sysv_sem.c:545–552

}

static int
semvalid(int semid, struct prison *rpr, struct semid_kernel *semakptr)
{

	return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
	    semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ||
	    sem_prison_cansee(rpr, semakptr) ? EINVAL : 0);
}

static void
sem_remove(int semidx, struct ucred *cred)