int
__new_sem_post (sem_t *sem)
{
struct new_sem *isem = (struct new_sem *) sem;
__typeof (isem->value) cur;
do
{
cur = isem->value;
if (isem->value == SEM_VALUE_MAX)
{
__set_errno (EOVERFLOW);
return -1;
}
}
while (atomic_compare_and_exchange_bool_rel (&isem->value, cur + 1, cur));
atomic_full_barrier ();
if (isem->nwaiters > 0)
{
int err = lll_futex_wake (&isem->value, 1,
isem->private ^ FUTEX_PRIVATE_FLAG);
if (__builtin_expect (err, 0) < 0)
{
__set_errno (-err);
return -1;
}
}
/* Add a new entry to the cache. The return value is zero if the function
call was successful.
This function must be called with the read-lock held.
We modify the table but we nevertheless only acquire a read-lock.
This is ok since we use operations which would be safe even without
locking, given that the `prune_cache' function never runs. Using
the readlock reduces the chance of conflicts. */
int
cache_add (int type, const void *key, size_t len, struct datahead *packet,
bool first, struct database_dyn *table,
uid_t owner, bool prune_wakeup)
{
if (__glibc_unlikely (debug_level >= 2))
{
const char *str;
char buf[INET6_ADDRSTRLEN + 1];
if (type == GETHOSTBYADDR || type == GETHOSTBYADDRv6)
str = inet_ntop (type == GETHOSTBYADDR ? AF_INET : AF_INET6,
key, buf, sizeof (buf));
else
str = key;
dbg_log (_("add new entry \"%s\" of type %s for %s to cache%s"),
str, serv2str[type], dbnames[table - dbs],
first ? _(" (first)") : "");
}
unsigned long int hash = __nis_hash (key, len) % table->head->module;
struct hashentry *newp;
newp = mempool_alloc (table, sizeof (struct hashentry), 0);
/* If we cannot allocate memory, just do not do anything. */
if (newp == NULL)
{
/* If necessary mark the entry as unusable so that lookups will
not use it. */
if (first)
packet->usable = false;
return -1;
}
newp->type = type;
newp->first = first;
newp->len = len;
newp->key = (char *) key - table->data;
assert (newp->key + newp->len <= table->head->first_free);
newp->owner = owner;
newp->packet = (char *) packet - table->data;
assert ((newp->packet & BLOCK_ALIGN_M1) == 0);
/* Put the new entry in the first position. */
do
newp->next = table->head->array[hash];
while (atomic_compare_and_exchange_bool_rel (&table->head->array[hash],
(ref_t) ((char *) newp
- table->data),
(ref_t) newp->next));
/* Update the statistics. */
if (packet->notfound)
++table->head->negmiss;
else if (first)
++table->head->posmiss;
/* We depend on this value being correct and at least as high as the
real number of entries. */
atomic_increment (&table->head->nentries);
/* It does not matter that we are not loading the just increment
value, this is just for statistics. */
unsigned long int nentries = table->head->nentries;
if (nentries > table->head->maxnentries)
table->head->maxnentries = nentries;
if (table->persistent)
// XXX async OK?
msync ((void *) table->head,
(char *) &table->head->array[hash] - (char *) table->head
+ sizeof (ref_t), MS_ASYNC);
/* We do not have to worry about the pruning thread if we are
re-adding the data since this is done by the pruning thread. We
also do not have to do anything in case this is not the first
time the data is entered since different data heads all have the
same timeout. */
if (first && prune_wakeup)
{
/* Perhaps the prune thread for the table is not running in a long
time. Wake it if necessary. */
pthread_mutex_lock (&table->prune_lock);
time_t next_wakeup = table->wakeup_time;
bool do_wakeup = false;
if (next_wakeup > packet->timeout + CACHE_PRUNE_INTERVAL)
{
table->wakeup_time = packet->timeout;
do_wakeup = true;
}
pthread_mutex_unlock (&table->prune_lock);
if (do_wakeup)
pthread_cond_signal (&table->prune_cond);
}
return 0;
}
