+ * 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.