+ * The caller must ensure that the application is compatible and is tracked
+ * by the PID tracker.
+ */
+static
+void ust_app_synchronize(struct ltt_ust_session *usess,
+ struct ust_app *app)
+{
+ int ret = 0;
+ struct cds_lfht_iter uchan_iter;
+ struct ltt_ust_channel *uchan;
+ struct ust_app_session *ua_sess = NULL;
+
+ /*
+ * The application's configuration should only be synchronized for
+ * active sessions.
+ */
+ assert(usess->active);
+
+ ret = find_or_create_ust_app_session(usess, app, &ua_sess, NULL);
+ if (ret < 0) {
+ /* Tracer is probably gone or ENOMEM. */
+ goto error;
+ }
+ assert(ua_sess);
+
+ pthread_mutex_lock(&ua_sess->lock);
+ if (ua_sess->deleted) {
+ pthread_mutex_unlock(&ua_sess->lock);
+ goto end;
+ }
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(usess->domain_global.channels->ht, &uchan_iter,
+ uchan, node.node) {
+ struct ust_app_channel *ua_chan;
+ struct cds_lfht_iter uevent_iter;
+ struct ltt_ust_event *uevent;
+
+ /*
+ * Search for a matching ust_app_channel. If none is found,
+ * create it. Creating the channel will cause the ua_chan
+ * structure to be allocated, the channel buffers to be
+ * allocated (if necessary) and sent to the application, and
+ * all enabled contexts will be added to the channel.
+ */
+ ret = find_or_create_ust_app_channel(usess, ua_sess,
+ app, uchan, &ua_chan);
+ if (ret) {
+ /* Tracer is probably gone or ENOMEM. */
+ goto error_unlock;
+ }
+
+ if (!ua_chan) {
+ /* ua_chan will be NULL for the metadata channel */
+ continue;
+ }
+
+ cds_lfht_for_each_entry(uchan->events->ht, &uevent_iter, uevent,
+ node.node) {
+ ret = ust_app_channel_synchronize_event(ua_chan,
+ uevent, ua_sess, app);
+ if (ret) {
+ goto error_unlock;
+ }
+ }
+
+ if (ua_chan->enabled != uchan->enabled) {
+ ret = uchan->enabled ?
+ enable_ust_app_channel(ua_sess, uchan, app) :
+ disable_ust_app_channel(ua_sess, ua_chan, app);
+ if (ret) {
+ goto error_unlock;
+ }
+ }
+ }
+ rcu_read_unlock();
+
+end:
+ pthread_mutex_unlock(&ua_sess->lock);
+ /* Everything went well at this point. */
+ return;
+
+error_unlock:
+ rcu_read_unlock();
+ pthread_mutex_unlock(&ua_sess->lock);
+error:
+ if (ua_sess) {
+ destroy_app_session(app, ua_sess);
+ }
+ return;
+}
+
+static
+void ust_app_global_destroy(struct ltt_ust_session *usess, struct ust_app *app)
+{
+ struct ust_app_session *ua_sess;
+
+ ua_sess = lookup_session_by_app(usess, app);
+ if (ua_sess == NULL) {
+ return;
+ }
+ destroy_app_session(app, ua_sess);
+}
+
+/*
+ * Add channels/events from UST global domain to registered apps at sock.
+ *
+ * Called with session lock held.
+ * Called with RCU read-side lock held.
+ */
+void ust_app_global_update(struct ltt_ust_session *usess, struct ust_app *app)
+{
+ assert(usess);
+ assert(usess->active);
+
+ DBG2("UST app global update for app sock %d for session id %" PRIu64,
+ app->sock, usess->id);
+
+ if (!app->compatible) {
+ return;
+ }
+ if (trace_ust_id_tracker_lookup(LTTNG_TRACKER_VPID, usess, app->pid) &&
+ trace_ust_id_tracker_lookup(
+ LTTNG_TRACKER_VUID, usess, app->uid) &&
+ trace_ust_id_tracker_lookup(
+ LTTNG_TRACKER_VGID, usess, app->gid)) {
+ /*
+ * Synchronize the application's internal tracing configuration
+ * and start tracing.
+ */
+ ust_app_synchronize(usess, app);
+ ust_app_start_trace(usess, app);
+ } else {
+ ust_app_global_destroy(usess, app);
+ }
+}
+
+void ust_app_global_update_tokens(struct ust_app *app)
+{
+ DBG2("UST app global update token for app sock %d", app->sock);
+
+ if (!app->compatible) {
+ return;
+ }
+ ust_app_synchronize_tokens(app);
+}
+
+/*
+ * Called with session lock held.
+ */
+void ust_app_global_update_all(struct ltt_ust_session *usess)
+{
+ struct lttng_ht_iter iter;
+ struct ust_app *app;
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+ ust_app_global_update(usess, app);
+ }
+ rcu_read_unlock();
+}
+
+void ust_app_global_update_all_tokens(void)
+{
+ struct lttng_ht_iter iter;
+ struct ust_app *app;
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+ ust_app_global_update_tokens(app);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Add context to a specific channel for global UST domain.
+ */
+int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
+ struct ltt_ust_channel *uchan, struct ltt_ust_context *uctx)
+{
+ int ret = 0;
+ struct lttng_ht_node_str *ua_chan_node;
+ struct lttng_ht_iter iter, uiter;
+ struct ust_app_channel *ua_chan = NULL;
+ struct ust_app_session *ua_sess;
+ struct ust_app *app;
+
+ assert(usess->active);
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+ if (!app->compatible) {
+ /*
+ * TODO: In time, we should notice the caller of this error by
+ * telling him that this is a version error.
+ */
+ continue;
+ }
+ ua_sess = lookup_session_by_app(usess, app);
+ if (ua_sess == NULL) {
+ continue;
+ }
+
+ pthread_mutex_lock(&ua_sess->lock);
+
+ if (ua_sess->deleted) {
+ pthread_mutex_unlock(&ua_sess->lock);
+ continue;
+ }
+
+ /* Lookup channel in the ust app session */
+ lttng_ht_lookup(ua_sess->channels, (void *)uchan->name, &uiter);
+ ua_chan_node = lttng_ht_iter_get_node_str(&uiter);
+ if (ua_chan_node == NULL) {
+ goto next_app;
+ }
+ ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel,
+ node);
+ ret = create_ust_app_channel_context(ua_chan, &uctx->ctx, app);
+ if (ret < 0) {
+ goto next_app;
+ }
+ next_app:
+ pthread_mutex_unlock(&ua_sess->lock);
+ }
+
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Receive registration and populate the given msg structure.
+ *
+ * On success return 0 else a negative value returned by the ustctl call.
+ */
+int ust_app_recv_registration(int sock, struct ust_register_msg *msg)
+{
+ int ret;
+ uint32_t pid, ppid, uid, gid;
+
+ assert(msg);
+
+ ret = ustctl_recv_reg_msg(sock, &msg->type, &msg->major, &msg->minor,
+ &pid, &ppid, &uid, &gid,
+ &msg->bits_per_long,
+ &msg->uint8_t_alignment,
+ &msg->uint16_t_alignment,
+ &msg->uint32_t_alignment,
+ &msg->uint64_t_alignment,
+ &msg->long_alignment,
+ &msg->byte_order,
+ msg->name);
+ if (ret < 0) {
+ switch (-ret) {
+ case EPIPE:
+ case ECONNRESET:
+ case LTTNG_UST_ERR_EXITING:
+ DBG3("UST app recv reg message failed. Application died");
+ break;
+ case LTTNG_UST_ERR_UNSUP_MAJOR:
+ ERR("UST app recv reg unsupported version %d.%d. Supporting %d.%d",
+ msg->major, msg->minor, LTTNG_UST_ABI_MAJOR_VERSION,
+ LTTNG_UST_ABI_MINOR_VERSION);
+ break;
+ default:
+ ERR("UST app recv reg message failed with ret %d", ret);
+ break;
+ }
+ goto error;
+ }
+ msg->pid = (pid_t) pid;
+ msg->ppid = (pid_t) ppid;
+ msg->uid = (uid_t) uid;
+ msg->gid = (gid_t) gid;
+
+error:
+ return ret;
+}
+
+/*
+ * Return a ust app session object using the application object and the
+ * session object descriptor has a key. If not found, NULL is returned.
+ * A RCU read side lock MUST be acquired when calling this function.
+*/
+static struct ust_app_session *find_session_by_objd(struct ust_app *app,
+ int objd)
+{
+ struct lttng_ht_node_ulong *node;
+ struct lttng_ht_iter iter;
+ struct ust_app_session *ua_sess = NULL;
+
+ assert(app);
+
+ lttng_ht_lookup(app->ust_sessions_objd, (void *)((unsigned long) objd), &iter);
+ node = lttng_ht_iter_get_node_ulong(&iter);
+ if (node == NULL) {
+ DBG2("UST app session find by objd %d not found", objd);
+ goto error;
+ }
+
+ ua_sess = caa_container_of(node, struct ust_app_session, ust_objd_node);
+
+error:
+ return ua_sess;
+}
+
+/*
+ * Return a ust app channel object using the application object and the channel
+ * object descriptor has a key. If not found, NULL is returned. A RCU read side
+ * lock MUST be acquired before calling this function.
+ */
+static struct ust_app_channel *find_channel_by_objd(struct ust_app *app,
+ int objd)
+{
+ struct lttng_ht_node_ulong *node;
+ struct lttng_ht_iter iter;
+ struct ust_app_channel *ua_chan = NULL;
+
+ assert(app);
+
+ lttng_ht_lookup(app->ust_objd, (void *)((unsigned long) objd), &iter);
+ node = lttng_ht_iter_get_node_ulong(&iter);
+ if (node == NULL) {
+ DBG2("UST app channel find by objd %d not found", objd);
+ goto error;
+ }
+
+ ua_chan = caa_container_of(node, struct ust_app_channel, ust_objd_node);
+
+error:
+ return ua_chan;
+}
+
+/*
+ * Reply to a register channel notification from an application on the notify
+ * socket. The channel metadata is also created.
+ *
+ * The session UST registry lock is acquired in this function.
+ *
+ * On success 0 is returned else a negative value.
+ */
+static int reply_ust_register_channel(int sock, int cobjd,
+ size_t nr_fields, struct ustctl_field *fields)
+{
+ int ret, ret_code = 0;
+ uint32_t chan_id;
+ uint64_t chan_reg_key;
+ enum ustctl_channel_header type;
+ struct ust_app *app;
+ struct ust_app_channel *ua_chan;
+ struct ust_app_session *ua_sess;
+ struct ust_registry_session *registry;
+ struct ust_registry_channel *chan_reg;
+
+ rcu_read_lock();
+
+ /* Lookup application. If not found, there is a code flow error. */
+ app = find_app_by_notify_sock(sock);
+ if (!app) {
+ DBG("Application socket %d is being torn down. Abort event notify",
+ sock);
+ ret = 0;
+ goto error_rcu_unlock;
+ }
+
+ /* Lookup channel by UST object descriptor. */
+ ua_chan = find_channel_by_objd(app, cobjd);
+ if (!ua_chan) {
+ DBG("Application channel is being torn down. Abort event notify");
+ ret = 0;
+ goto error_rcu_unlock;
+ }
+
+ assert(ua_chan->session);
+ ua_sess = ua_chan->session;
+
+ /* Get right session registry depending on the session buffer type. */
+ registry = get_session_registry(ua_sess);
+ if (!registry) {
+ DBG("Application session is being torn down. Abort event notify");
+ ret = 0;
+ goto error_rcu_unlock;
+ };
+
+ /* Depending on the buffer type, a different channel key is used. */
+ if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
+ chan_reg_key = ua_chan->tracing_channel_id;
+ } else {
+ chan_reg_key = ua_chan->key;
+ }
+
+ pthread_mutex_lock(®istry->lock);
+
+ chan_reg = ust_registry_channel_find(registry, chan_reg_key);
+ assert(chan_reg);
+
+ if (!chan_reg->register_done) {
+ /*
+ * TODO: eventually use the registry event count for
+ * this channel to better guess header type for per-pid
+ * buffers.
+ */
+ type = USTCTL_CHANNEL_HEADER_LARGE;
+ chan_reg->nr_ctx_fields = nr_fields;
+ chan_reg->ctx_fields = fields;
+ fields = NULL;
+ chan_reg->header_type = type;
+ } else {
+ /* Get current already assigned values. */
+ type = chan_reg->header_type;
+ }
+ /* Channel id is set during the object creation. */
+ chan_id = chan_reg->chan_id;
+
+ /* Append to metadata */
+ if (!chan_reg->metadata_dumped) {
+ ret_code = ust_metadata_channel_statedump(registry, chan_reg);
+ if (ret_code) {
+ ERR("Error appending channel metadata (errno = %d)", ret_code);
+ goto reply;
+ }
+ }
+
+reply:
+ DBG3("UST app replying to register channel key %" PRIu64
+ " with id %u, type: %d, ret: %d", chan_reg_key, chan_id, type,
+ ret_code);
+
+ ret = ustctl_reply_register_channel(sock, chan_id, type, ret_code);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app reply channel failed with ret %d", ret);
+ } else {
+ DBG3("UST app reply channel failed. Application died");
+ }
+ goto error;
+ }
+
+ /* This channel registry registration is completed. */
+ chan_reg->register_done = 1;
+
+error:
+ pthread_mutex_unlock(®istry->lock);
+error_rcu_unlock:
+ rcu_read_unlock();
+ free(fields);
+ return ret;
+}
+
+/*
+ * Add event to the UST channel registry. When the event is added to the