+ /*
+ * Create the metadata for the application. This returns gracefully if a
+ * metadata was already set for the session.
+ *
+ * The metadata channel must be created after the data channels as the
+ * consumer daemon assumes this ordering. When interacting with a relay
+ * daemon, the consumer will use this assumption to send the
+ * "STREAMS_SENT" message to the relay daemon.
+ */
+ ret = create_ust_app_metadata(ua_sess, app, usess->consumer);
+ if (ret < 0) {
+ 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_PROCESS_ATTR_VIRTUAL_PROCESS_ID,
+ usess, app->pid) &&
+ trace_ust_id_tracker_lookup(
+ LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID,
+ usess, app->uid) &&
+ trace_ust_id_tracker_lookup(
+ LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID,
+ 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);
+ }
+}
+
+/*
+ * Add all event notifiers to an application.
+ *
+ * Called with session lock held.
+ * Called with RCU read-side lock held.
+ */
+void ust_app_global_update_event_notifier_rules(struct ust_app *app)
+{
+ DBG2("UST application global event notifier rules update: app = '%s' (ppid: %d)",
+ app->name, app->ppid);
+
+ if (!app->compatible) {
+ return;
+ }
+
+ if (app->event_notifier_group.object == NULL) {
+ WARN("UST app global update of event notifiers for app skipped since communication handle is null: app = '%s' (ppid: %d)",
+ app->name, app->ppid);
+ return;
+ }
+
+ ust_app_synchronize_event_notifier_rules(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_event_notifier_rules(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_event_notifier_rules(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 *ust_reg_chan;
+
+ 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);
+
+ ust_reg_chan = ust_registry_channel_find(registry, chan_reg_key);
+ assert(ust_reg_chan);
+
+ if (!ust_reg_chan->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;
+ ust_reg_chan->nr_ctx_fields = nr_fields;
+ ust_reg_chan->ctx_fields = fields;
+ fields = NULL;
+ ust_reg_chan->header_type = type;
+ } else {
+ /* Get current already assigned values. */
+ type = ust_reg_chan->header_type;
+ }
+ /* Channel id is set during the object creation. */
+ chan_id = ust_reg_chan->chan_id;
+
+ /* Append to metadata */
+ if (!ust_reg_chan->metadata_dumped) {
+ ret_code = ust_metadata_channel_statedump(registry, ust_reg_chan);
+ 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. */
+ ust_reg_chan->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
+ * registry, the metadata is also created. Once done, this replies to the
+ * application with the appropriate error code.
+ *
+ * The session UST registry lock is acquired in the function.
+ *
+ * On success 0 is returned else a negative value.
+ */
+static int add_event_ust_registry(int sock, int sobjd, int cobjd, char *name,
+ char *sig, size_t nr_fields, struct ustctl_field *fields,
+ int loglevel_value, char *model_emf_uri)
+{
+ int ret, ret_code;
+ uint32_t event_id = 0;
+ uint64_t chan_reg_key;
+ struct ust_app *app;
+ struct ust_app_channel *ua_chan;
+ struct ust_app_session *ua_sess;
+ struct ust_registry_session *registry;
+
+ 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;
+
+ registry = get_session_registry(ua_sess);
+ if (!registry) {
+ DBG("Application session is being torn down. Abort event notify");
+ ret = 0;
+ goto error_rcu_unlock;
+ }
+
+ 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);
+
+ /*
+ * From this point on, this call acquires the ownership of the sig, fields
+ * and model_emf_uri meaning any free are done inside it if needed. These
+ * three variables MUST NOT be read/write after this.
+ */
+ ret_code = ust_registry_create_event(registry, chan_reg_key,
+ sobjd, cobjd, name, sig, nr_fields, fields,
+ loglevel_value, model_emf_uri, ua_sess->buffer_type,
+ &event_id, app);
+ sig = NULL;
+ fields = NULL;
+ model_emf_uri = NULL;
+
+ /*
+ * The return value is returned to ustctl so in case of an error, the
+ * application can be notified. In case of an error, it's important not to
+ * return a negative error or else the application will get closed.
+ */
+ ret = ustctl_reply_register_event(sock, event_id, ret_code);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app reply event failed with ret %d", ret);
+ } else {
+ DBG3("UST app reply event failed. Application died");
+ }
+ /*
+ * No need to wipe the create event since the application socket will
+ * get close on error hence cleaning up everything by itself.
+ */
+ goto error;
+ }
+
+ DBG3("UST registry event %s with id %" PRId32 " added successfully",
+ name, event_id);
+
+error:
+ pthread_mutex_unlock(®istry->lock);
+error_rcu_unlock:
+ rcu_read_unlock();
+ free(sig);
+ free(fields);
+ free(model_emf_uri);
+ return ret;
+}
+
+/*
+ * Add enum to the UST session registry. Once done, this replies to the
+ * application with the appropriate error code.
+ *
+ * The session UST registry lock is acquired within this function.
+ *
+ * On success 0 is returned else a negative value.
+ */
+static int add_enum_ust_registry(int sock, int sobjd, char *name,
+ struct ustctl_enum_entry *entries, size_t nr_entries)
+{
+ int ret = 0, ret_code;
+ struct ust_app *app;
+ struct ust_app_session *ua_sess;
+ struct ust_registry_session *registry;
+ uint64_t enum_id = -1ULL;
+
+ rcu_read_lock();
+
+ /* Lookup application. If not found, there is a code flow error. */
+ app = find_app_by_notify_sock(sock);
+ if (!app) {
+ /* Return an error since this is not an error */
+ DBG("Application socket %d is being torn down. Aborting enum registration",
+ sock);
+ free(entries);
+ goto error_rcu_unlock;
+ }
+
+ /* Lookup session by UST object descriptor. */
+ ua_sess = find_session_by_objd(app, sobjd);
+ if (!ua_sess) {
+ /* Return an error since this is not an error */
+ DBG("Application session is being torn down (session not found). Aborting enum registration.");
+ free(entries);
+ goto error_rcu_unlock;
+ }
+
+ registry = get_session_registry(ua_sess);
+ if (!registry) {
+ DBG("Application session is being torn down (registry not found). Aborting enum registration.");
+ free(entries);
+ goto error_rcu_unlock;
+ }
+
+ pthread_mutex_lock(®istry->lock);
+
+ /*
+ * From this point on, the callee acquires the ownership of
+ * entries. The variable entries MUST NOT be read/written after
+ * call.
+ */
+ ret_code = ust_registry_create_or_find_enum(registry, sobjd, name,
+ entries, nr_entries, &enum_id);
+ entries = NULL;
+
+ /*
+ * The return value is returned to ustctl so in case of an error, the
+ * application can be notified. In case of an error, it's important not to
+ * return a negative error or else the application will get closed.
+ */
+ ret = ustctl_reply_register_enum(sock, enum_id, ret_code);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app reply enum failed with ret %d", ret);
+ } else {
+ DBG3("UST app reply enum failed. Application died");
+ }
+ /*
+ * No need to wipe the create enum since the application socket will
+ * get close on error hence cleaning up everything by itself.
+ */
+ goto error;
+ }
+
+ DBG3("UST registry enum %s added successfully or already found", name);
+
+error:
+ pthread_mutex_unlock(®istry->lock);
+error_rcu_unlock:
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Handle application notification through the given notify socket.
+ *
+ * Return 0 on success or else a negative value.
+ */
+int ust_app_recv_notify(int sock)
+{
+ int ret;
+ enum ustctl_notify_cmd cmd;
+
+ DBG3("UST app receiving notify from sock %d", sock);
+
+ ret = ustctl_recv_notify(sock, &cmd);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app recv notify failed with ret %d", ret);
+ } else {
+ DBG3("UST app recv notify failed. Application died");
+ }
+ goto error;
+ }
+
+ switch (cmd) {
+ case USTCTL_NOTIFY_CMD_EVENT:
+ {
+ int sobjd, cobjd, loglevel_value;
+ char name[LTTNG_UST_ABI_SYM_NAME_LEN], *sig, *model_emf_uri;
+ size_t nr_fields;
+ struct ustctl_field *fields;
+
+ DBG2("UST app ustctl register event received");
+
+ ret = ustctl_recv_register_event(sock, &sobjd, &cobjd, name,
+ &loglevel_value, &sig, &nr_fields, &fields,
+ &model_emf_uri);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app recv event failed with ret %d", ret);
+ } else {
+ DBG3("UST app recv event failed. Application died");
+ }
+ goto error;
+ }
+
+ /*
+ * Add event to the UST registry coming from the notify socket. This
+ * call will free if needed the sig, fields and model_emf_uri. This
+ * code path loses the ownsership of these variables and transfer them
+ * to the this function.
+ */
+ ret = add_event_ust_registry(sock, sobjd, cobjd, name, sig, nr_fields,
+ fields, loglevel_value, model_emf_uri);
+ if (ret < 0) {
+ goto error;
+ }
+
+ break;
+ }
+ case USTCTL_NOTIFY_CMD_CHANNEL:
+ {
+ int sobjd, cobjd;
+ size_t nr_fields;
+ struct ustctl_field *fields;
+
+ DBG2("UST app ustctl register channel received");
+
+ ret = ustctl_recv_register_channel(sock, &sobjd, &cobjd, &nr_fields,
+ &fields);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app recv channel failed with ret %d", ret);
+ } else {
+ DBG3("UST app recv channel failed. Application died");
+ }
+ goto error;
+ }
+
+ /*
+ * The fields ownership are transfered to this function call meaning
+ * that if needed it will be freed. After this, it's invalid to access
+ * fields or clean it up.
+ */
+ ret = reply_ust_register_channel(sock, cobjd, nr_fields,
+ fields);
+ if (ret < 0) {
+ goto error;
+ }
+
+ break;
+ }
+ case USTCTL_NOTIFY_CMD_ENUM:
+ {
+ int sobjd;
+ char name[LTTNG_UST_ABI_SYM_NAME_LEN];
+ size_t nr_entries;
+ struct ustctl_enum_entry *entries;
+
+ DBG2("UST app ustctl register enum received");
+
+ ret = ustctl_recv_register_enum(sock, &sobjd, name,
+ &entries, &nr_entries);
+ if (ret < 0) {
+ if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
+ ERR("UST app recv enum failed with ret %d", ret);
+ } else {
+ DBG3("UST app recv enum failed. Application died");
+ }
+ goto error;
+ }
+
+ /* Callee assumes ownership of entries */
+ ret = add_enum_ust_registry(sock, sobjd, name,
+ entries, nr_entries);
+ if (ret < 0) {
+ goto error;
+ }
+
+ break;
+ }
+ default:
+ /* Should NEVER happen. */
+ assert(0);
+ }
+
+error:
+ return ret;
+}
+
+/*
+ * Once the notify socket hangs up, this is called. First, it tries to find the
+ * corresponding application. On failure, the call_rcu to close the socket is
+ * executed. If an application is found, it tries to delete it from the notify
+ * socket hash table. Whathever the result, it proceeds to the call_rcu.
+ *
+ * Note that an object needs to be allocated here so on ENOMEM failure, the
+ * call RCU is not done but the rest of the cleanup is.
+ */
+void ust_app_notify_sock_unregister(int sock)
+{
+ int err_enomem = 0;
+ struct lttng_ht_iter iter;
+ struct ust_app *app;
+ struct ust_app_notify_sock_obj *obj;
+
+ assert(sock >= 0);
+
+ rcu_read_lock();
+
+ obj = zmalloc(sizeof(*obj));
+ if (!obj) {
+ /*
+ * An ENOMEM is kind of uncool. If this strikes we continue the
+ * procedure but the call_rcu will not be called. In this case, we
+ * accept the fd leak rather than possibly creating an unsynchronized
+ * state between threads.
+ *
+ * TODO: The notify object should be created once the notify socket is
+ * registered and stored independantely from the ust app object. The
+ * tricky part is to synchronize the teardown of the application and
+ * this notify object. Let's keep that in mind so we can avoid this
+ * kind of shenanigans with ENOMEM in the teardown path.
+ */
+ err_enomem = 1;
+ } else {
+ obj->fd = sock;
+ }
+
+ DBG("UST app notify socket unregister %d", sock);
+
+ /*
+ * Lookup application by notify socket. If this fails, this means that the
+ * hash table delete has already been done by the application
+ * unregistration process so we can safely close the notify socket in a
+ * call RCU.
+ */
+ app = find_app_by_notify_sock(sock);
+ if (!app) {
+ goto close_socket;
+ }
+
+ iter.iter.node = &app->notify_sock_n.node;
+
+ /*
+ * Whatever happens here either we fail or succeed, in both cases we have
+ * to close the socket after a grace period to continue to the call RCU
+ * here. If the deletion is successful, the application is not visible
+ * anymore by other threads and is it fails it means that it was already
+ * deleted from the hash table so either way we just have to close the
+ * socket.
+ */
+ (void) lttng_ht_del(ust_app_ht_by_notify_sock, &iter);
+
+close_socket:
+ rcu_read_unlock();
+
+ /*
+ * Close socket after a grace period to avoid for the socket to be reused
+ * before the application object is freed creating potential race between
+ * threads trying to add unique in the global hash table.
+ */
+ if (!err_enomem) {
+ call_rcu(&obj->head, close_notify_sock_rcu);
+ }
+}
+
+/*
+ * Destroy a ust app data structure and free its memory.
+ */
+void ust_app_destroy(struct ust_app *app)
+{
+ if (!app) {
+ return;
+ }
+
+ call_rcu(&app->pid_n.head, delete_ust_app_rcu);
+}
+
+/*
+ * Take a snapshot for a given UST session. The snapshot is sent to the given
+ * output.
+ *
+ * Returns LTTNG_OK on success or a LTTNG_ERR error code.
+ */
+enum lttng_error_code ust_app_snapshot_record(
+ const struct ltt_ust_session *usess,
+ const struct consumer_output *output, int wait,
+ uint64_t nb_packets_per_stream)
+{
+ int ret = 0;
+ enum lttng_error_code status = LTTNG_OK;
+ struct lttng_ht_iter iter;
+ struct ust_app *app;
+ char *trace_path = NULL;
+
+ assert(usess);
+ assert(output);
+
+ rcu_read_lock();
+
+ switch (usess->buffer_type) {
+ case LTTNG_BUFFER_PER_UID:
+ {
+ struct buffer_reg_uid *reg;
+
+ cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) {
+ struct buffer_reg_channel *buf_reg_chan;
+ struct consumer_socket *socket;
+ char pathname[PATH_MAX];
+ size_t consumer_path_offset = 0;
+
+ if (!reg->registry->reg.ust->metadata_key) {
+ /* Skip since no metadata is present */
+ continue;
+ }
+
+ /* Get consumer socket to use to push the metadata.*/
+ socket = consumer_find_socket_by_bitness(reg->bits_per_long,
+ usess->consumer);
+ if (!socket) {
+ status = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ memset(pathname, 0, sizeof(pathname));
+ ret = snprintf(pathname, sizeof(pathname),
+ DEFAULT_UST_TRACE_DIR "/" DEFAULT_UST_TRACE_UID_PATH,
+ reg->uid, reg->bits_per_long);
+ if (ret < 0) {
+ PERROR("snprintf snapshot path");
+ status = LTTNG_ERR_INVALID;
+ goto error;
+ }
+ /* Free path allowed on previous iteration. */
+ free(trace_path);
+ trace_path = setup_channel_trace_path(usess->consumer, pathname,
+ &consumer_path_offset);
+ if (!trace_path) {
+ status = LTTNG_ERR_INVALID;
+ goto error;
+ }
+ /* Add the UST default trace dir to path. */
+ cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter,
+ buf_reg_chan, node.node) {
+ status = consumer_snapshot_channel(socket,
+ buf_reg_chan->consumer_key,
+ output, 0, usess->uid,
+ usess->gid, &trace_path[consumer_path_offset], wait,
+ nb_packets_per_stream);
+ if (status != LTTNG_OK) {
+ goto error;
+ }
+ }
+ status = consumer_snapshot_channel(socket,
+ reg->registry->reg.ust->metadata_key, output, 1,
+ usess->uid, usess->gid, &trace_path[consumer_path_offset],
+ wait, 0);
+ if (status != LTTNG_OK) {
+ goto error;
+ }
+ }
+ break;
+ }
+ case LTTNG_BUFFER_PER_PID:
+ {
+ cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+ struct consumer_socket *socket;
+ struct lttng_ht_iter chan_iter;
+ struct ust_app_channel *ua_chan;
+ struct ust_app_session *ua_sess;
+ struct ust_registry_session *registry;
+ char pathname[PATH_MAX];
+ size_t consumer_path_offset = 0;
+
+ ua_sess = lookup_session_by_app(usess, app);
+ if (!ua_sess) {
+ /* Session not associated with this app. */
+ continue;
+ }
+
+ /* Get the right consumer socket for the application. */
+ socket = consumer_find_socket_by_bitness(app->bits_per_long,
+ output);
+ if (!socket) {
+ status = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ /* Add the UST default trace dir to path. */
+ memset(pathname, 0, sizeof(pathname));
+ ret = snprintf(pathname, sizeof(pathname), DEFAULT_UST_TRACE_DIR "/%s",
+ ua_sess->path);
+ if (ret < 0) {
+ status = LTTNG_ERR_INVALID;
+ PERROR("snprintf snapshot path");
+ goto error;
+ }
+ /* Free path allowed on previous iteration. */
+ free(trace_path);
+ trace_path = setup_channel_trace_path(usess->consumer, pathname,
+ &consumer_path_offset);
+ if (!trace_path) {
+ status = LTTNG_ERR_INVALID;
+ goto error;
+ }
+ cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter,
+ ua_chan, node.node) {
+ status = consumer_snapshot_channel(socket,
+ ua_chan->key, output, 0,
+ lttng_credentials_get_uid(&ua_sess->effective_credentials),
+ lttng_credentials_get_gid(&ua_sess->effective_credentials),
+ &trace_path[consumer_path_offset], wait,
+ nb_packets_per_stream);
+ switch (status) {
+ case LTTNG_OK:
+ break;
+ case LTTNG_ERR_CHAN_NOT_FOUND:
+ continue;
+ default:
+ goto error;
+ }
+ }
+
+ registry = get_session_registry(ua_sess);
+ if (!registry) {
+ DBG("Application session is being torn down. Skip application.");
+ continue;
+ }
+ status = consumer_snapshot_channel(socket,
+ registry->metadata_key, output, 1,
+ lttng_credentials_get_uid(&ua_sess->effective_credentials),
+ lttng_credentials_get_gid(&ua_sess->effective_credentials),
+ &trace_path[consumer_path_offset], wait, 0);
+ switch (status) {
+ case LTTNG_OK:
+ break;
+ case LTTNG_ERR_CHAN_NOT_FOUND:
+ continue;
+ default:
+ goto error;
+ }
+ }
+ break;
+ }
+ default:
+ assert(0);
+ break;
+ }
+
+error:
+ free(trace_path);
+ rcu_read_unlock();
+ return status;
+}
+
+/*
+ * Return the size taken by one more packet per stream.
+ */
+uint64_t ust_app_get_size_one_more_packet_per_stream(
+ const struct ltt_ust_session *usess, uint64_t cur_nr_packets)
+{
+ uint64_t tot_size = 0;
+ struct ust_app *app;
+ struct lttng_ht_iter iter;
+
+ assert(usess);
+
+ switch (usess->buffer_type) {
+ case LTTNG_BUFFER_PER_UID:
+ {
+ struct buffer_reg_uid *reg;
+
+ cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) {
+ struct buffer_reg_channel *buf_reg_chan;
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter,
+ buf_reg_chan, node.node) {
+ if (cur_nr_packets >= buf_reg_chan->num_subbuf) {
+ /*
+ * Don't take channel into account if we
+ * already grab all its packets.
+ */
+ continue;
+ }
+ tot_size += buf_reg_chan->subbuf_size * buf_reg_chan->stream_count;
+ }
+ rcu_read_unlock();
+ }
+ break;
+ }
+ case LTTNG_BUFFER_PER_PID:
+ {
+ rcu_read_lock();
+ cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+ struct ust_app_channel *ua_chan;
+ struct ust_app_session *ua_sess;
+ struct lttng_ht_iter chan_iter;
+
+ ua_sess = lookup_session_by_app(usess, app);
+ if (!ua_sess) {
+ /* Session not associated with this app. */
+ continue;
+ }
+
+ cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter,
+ ua_chan, node.node) {
+ if (cur_nr_packets >= ua_chan->attr.num_subbuf) {
+ /*
+ * Don't take channel into account if we
+ * already grab all its packets.
+ */
+ continue;
+ }
+ tot_size += ua_chan->attr.subbuf_size * ua_chan->streams.count;
+ }
+ }
+ rcu_read_unlock();
+ break;
+ }
+ default:
+ assert(0);
+ break;