+/*
+ * Routine: ipc_mqueue_peek
+ * Purpose:
+ * Peek at a (non-set) message queue to see if it has a message
+ * matching the sequence number provided (if zero, then the
+ * first message in the queue) and return vital info about the
+ * message.
+ *
+ * Conditions:
+ * Locks may be held by callers, so this routine cannot block.
+ * Caller holds reference on the message queue.
+ */
+unsigned
+ipc_mqueue_peek(ipc_mqueue_t mq,
+ mach_port_seqno_t * seqnop,
+ mach_msg_size_t * msg_sizep,
+ mach_msg_id_t * msg_idp,
+ mach_msg_max_trailer_t * msg_trailerp)
+{
+ ipc_kmsg_queue_t kmsgq;
+ ipc_kmsg_t kmsg;
+ mach_port_seqno_t seqno, msgoff;
+ int res = 0;
+ spl_t s;
+
+ assert(!imq_is_set(mq));
+
+ s = splsched();
+ imq_lock(mq);
+
+ seqno = 0;
+ if (seqnop != NULL)
+ seqno = *seqnop;
+
+ if (seqno == 0) {
+ seqno = mq->imq_seqno;
+ msgoff = 0;
+ } else if (seqno >= mq->imq_seqno &&
+ seqno < mq->imq_seqno + mq->imq_msgcount) {
+ msgoff = seqno - mq->imq_seqno;
+ } else
+ goto out;
+
+ /* look for the message that would match that seqno */
+ kmsgq = &mq->imq_messages;
+ kmsg = ipc_kmsg_queue_first(kmsgq);
+ while (msgoff-- && kmsg != IKM_NULL) {
+ kmsg = ipc_kmsg_queue_next(kmsgq, kmsg);
+ }
+ if (kmsg == IKM_NULL)
+ goto out;
+
+ /* found one - return the requested info */
+ if (seqnop != NULL)
+ *seqnop = seqno;
+ if (msg_sizep != NULL)
+ *msg_sizep = kmsg->ikm_header->msgh_size;
+ if (msg_idp != NULL)
+ *msg_idp = kmsg->ikm_header->msgh_id;
+ if (msg_trailerp != NULL)
+ memcpy(msg_trailerp,
+ (mach_msg_max_trailer_t *)((vm_offset_t)kmsg->ikm_header +
+ round_msg(kmsg->ikm_header->msgh_size)),
+ sizeof(mach_msg_max_trailer_t));
+ res = 1;
+
+ out:
+ imq_unlock(mq);
+ splx(s);
+ return res;
+}
+
+
+/*
+ * peek at the contained port message queues, break prepost iteration as soon
+ * as we spot a message on one of the message queues referenced by the set's
+ * prepost list. No need to lock each message queue, as only the head of each
+ * queue is checked. If a message wasn't there before we entered here, no need
+ * to find it (if we do, great).
+ */
+static int mqueue_peek_iterator(void *ctx, struct waitq *waitq,
+ struct waitq_set *wqset)
+{
+ ipc_mqueue_t port_mq = (ipc_mqueue_t)waitq;
+ ipc_kmsg_queue_t kmsgs = &port_mq->imq_messages;
+
+ (void)ctx;
+ (void)wqset;
+
+ if (ipc_kmsg_queue_first(kmsgs) != IKM_NULL)
+ return WQ_ITERATE_BREAK; /* break out of the prepost iteration */
+
+ return WQ_ITERATE_CONTINUE;
+}
+
+/*
+ * Routine: ipc_mqueue_set_peek
+ * Purpose:
+ * Peek at a message queue set to see if it has any ports
+ * with messages.
+ *
+ * Conditions:
+ * Locks may be held by callers, so this routine cannot block.
+ * Caller holds reference on the message queue.
+ */
+unsigned
+ipc_mqueue_set_peek(ipc_mqueue_t mq)
+{
+ spl_t s;
+ int ret;
+
+ assert(imq_is_set(mq));
+
+ s = splsched();
+ imq_lock(mq);
+
+ ret = waitq_set_iterate_preposts(&mq->imq_set_queue, NULL,
+ mqueue_peek_iterator, NULL);
+
+ imq_unlock(mq);
+ splx(s);
+ return (ret == WQ_ITERATE_BREAK);
+}
+
+/*
+ * Routine: ipc_mqueue_set_gather_member_names
+ * Purpose:
+ * Discover all ports which are members of a given port set.
+ * Because the waitq linkage mechanism was redesigned to save
+ * significan amounts of memory, it no longer keeps back-pointers
+ * from a port set to a port. Therefore, we must iterate over all
+ * ports within a given IPC space and individually query them to
+ * see if they are members of the given set. Port names of ports
+ * found to be members of the given set will be gathered into the
+ * provided 'names' array. Actual returned names are limited to
+ * maxnames entries, but we keep counting the actual number of
+ * members to let the caller decide to retry if necessary.
+ *
+ * Conditions:
+ * Locks may be held by callers, so this routine cannot block.
+ * Caller holds reference on the message queue (via port set).
+ */
+void
+ipc_mqueue_set_gather_member_names(
+ ipc_space_t space,
+ ipc_mqueue_t set_mq,
+ ipc_entry_num_t maxnames,
+ mach_port_name_t *names,
+ ipc_entry_num_t *actualp)
+{
+ ipc_entry_t table;
+ ipc_entry_num_t tsize;
+ struct waitq_set *wqset;
+ ipc_entry_num_t actual = 0;
+
+ assert(set_mq != IMQ_NULL);
+ wqset = &set_mq->imq_set_queue;
+
+ assert(space != IS_NULL);
+ is_read_lock(space);
+ if (!is_active(space)) {
+ is_read_unlock(space);
+ goto out;
+ }
+
+ if (!waitq_set_is_valid(wqset)) {
+ is_read_unlock(space);
+ goto out;
+ }
+
+ table = space->is_table;
+ tsize = space->is_table_size;
+ for (ipc_entry_num_t idx = 0; idx < tsize; idx++) {
+ ipc_entry_t entry = &table[idx];
+
+ /* only receive rights can be members of port sets */
+ if ((entry->ie_bits & MACH_PORT_TYPE_RECEIVE) != MACH_PORT_TYPE_NONE) {
+ __IGNORE_WCASTALIGN(ipc_port_t port = (ipc_port_t)entry->ie_object);
+ ipc_mqueue_t mq = &port->ip_messages;
+
+ assert(IP_VALID(port));
+ if (ip_active(port) &&
+ waitq_member(&mq->imq_wait_queue, wqset)) {
+ if (actual < maxnames)
+ names[actual] = mq->imq_receiver_name;
+ actual++;
+ }
+ }
+ }
+
+ is_read_unlock(space);
+
+out:
+ *actualp = actual;
+}
+
+
projects / apple / xnu.git / blobdiff