Function sem_remove

freebsd/kern/sysv_sem.c:554–598

}

static void
sem_remove(int semidx, struct ucred *cred)
{
	struct semid_kernel *semakptr;
	int i;

	KASSERT(semidx >= 0 && semidx < seminfo.semmni,
	    ("semidx out of bounds"));
	mtx_assert(&sem_mtx, MA_OWNED);
	semakptr = &sema[semidx];
	KASSERT(semakptr->u.__sem_base - sem + semakptr->u.sem_nsems <= semtot,
	    ("sem_remove: sema %d corrupted sem pointer %p %p %d %d",
	    semidx, semakptr->u.__sem_base, sem, semakptr->u.sem_nsems,
	    semtot));

	semakptr->u.sem_perm.cuid = cred ? cred->cr_uid : 0;
	semakptr->u.sem_perm.uid = cred ? cred->cr_uid : 0;
	semakptr->u.sem_perm.mode = 0;
	racct_sub_cred(semakptr->cred, RACCT_NSEM, semakptr->u.sem_nsems);
	crfree(semakptr->cred);
	semakptr->cred = NULL;
	SEMUNDO_LOCK();
	semundo_clear(semidx, -1);
	SEMUNDO_UNLOCK();
#ifdef MAC
	mac_sysvsem_cleanup(semakptr);
#endif
	wakeup(semakptr);
	for (i = 0; i < seminfo.semmni; i++) {
		if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
		    sema[i].u.__sem_base > semakptr->u.__sem_base)
			mtx_lock_flags(&sema_mtx[i], LOP_DUPOK);
	}
	for (i = semakptr->u.__sem_base - sem + semakptr->u.sem_nsems;
	    i < semtot; i++)
		sem[i - semakptr->u.sem_nsems] = sem[i];
	for (i = 0; i < seminfo.semmni; i++) {
		if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
		    sema[i].u.__sem_base > semakptr->u.__sem_base) {
			sema[i].u.__sem_base -= semakptr->u.sem_nsems;
			mtx_unlock(&sema_mtx[i]);
		}
	}
	semtot -= semakptr->u.sem_nsems;
}

static struct prison *
sem_find_prison(struct ucred *cred)