struct lttng_trigger_list_element {
/* No ownership of the trigger object is assumed. */
- struct lttng_trigger *trigger;
+ const struct lttng_trigger *trigger;
struct cds_list_head node;
};
struct cds_list_head node;
};
+struct notification_client_list_element {
+ struct notification_client *client;
+ struct cds_list_head node;
+};
+
+/*
+ * Thread safety of notification_client and notification_client_list.
+ *
+ * The notification thread (main thread) and the action executor
+ * interact through client lists. Hence, when the action executor
+ * thread looks-up the list of clients subscribed to a given
+ * condition, it will acquire a reference to the list and lock it
+ * while attempting to communicate with the various clients.
+ *
+ * It is not necessary to reference-count clients as they are guaranteed
+ * to be 'alive' if they are present in a list and that list is locked. Indeed,
+ * removing references to the client from those subscription lists is part of
+ * the work performed on destruction of a client.
+ *
+ * No provision for other access scenarios are taken into account;
+ * this is the bare minimum to make these accesses safe and the
+ * notification thread's state is _not_ "thread-safe" in any general
+ * sense.
+ */
+struct notification_client_list {
+ pthread_mutex_t lock;
+ struct urcu_ref ref;
+ const struct lttng_trigger *trigger;
+ struct cds_list_head list;
+ /* Weak reference to container. */
+ struct cds_lfht *notification_trigger_clients_ht;
+ struct cds_lfht_node notification_trigger_clients_ht_node;
+ /* call_rcu delayed reclaim. */
+ struct rcu_head rcu_node;
+};
+
+struct notification_client {
+ /* Nests within the notification_client_list lock. */
+ pthread_mutex_t lock;
+ notification_client_id id;
+ int socket;
+ /* Client protocol version. */
+ uint8_t major, minor;
+ uid_t uid;
+ gid_t gid;
+ /*
+ * Indicates if the credentials and versions of the client have been
+ * checked.
+ */
+ bool validated;
+ /*
+ * Conditions to which the client's notification channel is subscribed.
+ * List of struct lttng_condition_list_node. The condition member is
+ * owned by the client.
+ */
+ struct cds_list_head condition_list;
+ struct cds_lfht_node client_socket_ht_node;
+ struct cds_lfht_node client_id_ht_node;
+ struct {
+ /*
+ * If a client's communication is inactive, it means that a
+ * fatal error has occurred (could be either a protocol error or
+ * the socket API returned a fatal error). No further
+ * communication should be attempted; the client is queued for
+ * clean-up.
+ */
+ bool active;
+ struct {
+ /*
+ * During the reception of a message, the reception
+ * buffers' "size" is set to contain the current
+ * message's complete payload.
+ */
+ struct lttng_dynamic_buffer buffer;
+ /* Bytes left to receive for the current message. */
+ size_t bytes_to_receive;
+ /* Type of the message being received. */
+ enum lttng_notification_channel_message_type msg_type;
+ /*
+ * Indicates whether or not credentials are expected
+ * from the client.
+ */
+ bool expect_creds;
+ /*
+ * Indicates whether or not credentials were received
+ * from the client.
+ */
+ bool creds_received;
+ /* Only used during credentials reception. */
+ lttng_sock_cred creds;
+ } inbound;
+ struct {
+ /*
+ * Indicates whether or not a notification addressed to
+ * this client was dropped because a command reply was
+ * already buffered.
+ *
+ * A notification is dropped whenever the buffer is not
+ * empty.
+ */
+ bool dropped_notification;
+ /*
+ * Indicates whether or not a command reply is already
+ * buffered. In this case, it means that the client is
+ * not consuming command replies before emitting a new
+ * one. This could be caused by a protocol error or a
+ * misbehaving/malicious client.
+ */
+ bool queued_command_reply;
+ struct lttng_dynamic_buffer buffer;
+ } outbound;
+ } communication;
+ /* call_rcu delayed reclaim. */
+ struct rcu_head rcu_node;
+};
+
struct channel_state_sample {
struct channel_key key;
struct cds_lfht_node channel_state_ht_node;
struct lttng_session_trigger_list *list);
static
int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list,
- struct lttng_trigger *trigger);
+ const struct lttng_trigger *trigger);
-static
-int client_handle_transmission_status(
- struct notification_client *client,
- enum client_transmission_status transmission_status,
- struct notification_thread_state *state);
static
int match_client_socket(struct cds_lfht_node *node, const void *key)
return NULL;
}
-LTTNG_HIDDEN
+static
bool notification_client_list_get(struct notification_client_list *list)
{
return urcu_ref_get_unless_zero(&list->ref);
rcu_read_unlock();
}
-LTTNG_HIDDEN
+static
void notification_client_list_put(struct notification_client_list *list)
{
if (!list) {
return client;
}
-/*
- * Call with rcu_read_lock held (and hold for the lifetime of the returned
- * client pointer).
- */
-static
-struct notification_client *get_client_from_id(notification_client_id id,
- struct notification_thread_state *state)
-{
- struct cds_lfht_iter iter;
- struct cds_lfht_node *node;
- struct notification_client *client = NULL;
-
- cds_lfht_lookup(state->client_id_ht,
- hash_client_id(id),
- match_client_id,
- &id,
- &iter);
- node = cds_lfht_iter_get_node(&iter);
- if (!node) {
- goto end;
- }
-
- client = caa_container_of(node, struct notification_client,
- client_id_ht_node);
-end:
- return client;
-}
-
static
bool buffer_usage_condition_applies_to_channel(
const struct lttng_condition *condition,
static
int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list,
- struct lttng_trigger *trigger)
+ const struct lttng_trigger *trigger)
{
int ret = 0;
struct lttng_trigger_list_element *new_element =
struct lttng_session_trigger_list *trigger_list;
struct lttng_trigger_list_element *trigger_list_element;
struct session_info *session_info;
- const struct lttng_credentials session_creds = {
- .uid = session_uid,
- .gid = session_gid,
- };
rcu_read_lock();
node) {
const struct lttng_condition *condition;
const struct lttng_action *action;
- struct lttng_trigger *trigger;
+ const struct lttng_trigger *trigger;
struct notification_client_list *client_list;
struct lttng_evaluation *evaluation = NULL;
enum lttng_condition_type condition_type;
bool client_list_is_empty;
- enum action_executor_status executor_status;
trigger = trigger_list_element->trigger;
condition = lttng_trigger_get_const_condition(trigger);
goto put_list;
}
- /*
- * Ownership of `evaluation` transferred to the action executor
- * no matter the result.
- */
- executor_status = action_executor_enqueue(state->executor,
- trigger, evaluation, &session_creds,
- client_list);
- evaluation = NULL;
- switch (executor_status) {
- case ACTION_EXECUTOR_STATUS_OK:
- break;
- case ACTION_EXECUTOR_STATUS_ERROR:
- case ACTION_EXECUTOR_STATUS_INVALID:
- /*
- * TODO Add trigger identification (name/id) when
- * it is added to the API.
- */
- ERR("Fatal error occurred while enqueuing action associated with session rotation trigger");
- ret = -1;
- goto put_list;
- case ACTION_EXECUTOR_STATUS_OVERFLOW:
- /*
- * TODO Add trigger identification (name/id) when
- * it is added to the API.
- *
- * Not a fatal error.
- */
- WARN("No space left when enqueuing action associated with session rotation trigger");
- ret = 0;
- goto put_list;
- default:
- abort();
- }
-
+ /* Dispatch evaluation result to all clients. */
+ ret = send_evaluation_to_clients(trigger_list_element->trigger,
+ evaluation, client_list, state,
+ session_info->uid,
+ session_info->gid);
+ lttng_evaluation_destroy(evaluation);
put_list:
notification_client_list_put(client_list);
if (caa_unlikely(ret)) {
/* Must be called with RCU read lock held. */
static
-int bind_trigger_to_matching_session(struct lttng_trigger *trigger,
+int bind_trigger_to_matching_session(const struct lttng_trigger *trigger,
struct notification_thread_state *state)
{
int ret = 0;
/* Must be called with RCU read lock held. */
static
-int bind_trigger_to_matching_channels(struct lttng_trigger *trigger,
+int bind_trigger_to_matching_channels(const struct lttng_trigger *trigger,
struct notification_thread_state *state)
{
int ret = 0;
cmd->reply_code = LTTNG_OK;
ret = 1;
goto end;
- case NOTIFICATION_COMMAND_TYPE_CLIENT_COMMUNICATION_UPDATE:
- {
- const enum client_transmission_status client_status =
- cmd->parameters.client_communication_update
- .status;
- const notification_client_id client_id =
- cmd->parameters.client_communication_update.id;
- struct notification_client *client;
-
- rcu_read_lock();
- client = get_client_from_id(client_id, state);
-
- if (!client) {
- /*
- * Client error was probably already picked-up by the
- * notification thread or it has disconnected
- * gracefully while this command was queued.
- */
- DBG("Failed to find notification client to update communication status, client id = %" PRIu64,
- client_id);
- ret = 0;
- } else {
- pthread_mutex_lock(&client->lock);
- ret = client_handle_transmission_status(
- client, client_status, state);
- pthread_mutex_unlock(&client->lock);
- }
- rcu_read_unlock();
- break;
- }
default:
ERR("[notification-thread] Unknown internal command received");
goto error_unlock;
/* Client lock must be acquired by caller. */
static
enum client_transmission_status client_flush_outgoing_queue(
- struct notification_client *client)
+ struct notification_client *client,
+ struct notification_thread_state *state)
{
ssize_t ret;
size_t to_send_count;
ASSERT_LOCKED(client->lock);
- if (!client->communication.active) {
- status = CLIENT_TRANSMISSION_STATUS_FAIL;
- goto end;
- }
-
assert(client->communication.outbound.buffer.size != 0);
to_send_count = client->communication.outbound.buffer.size;
DBG("[notification-thread] Flushing client (socket fd = %i) outgoing queue",
&client->communication.outbound.buffer,
to_send_count);
if (ret) {
+ status = CLIENT_TRANSMISSION_STATUS_ERROR;
goto error;
}
status = CLIENT_TRANSMISSION_STATUS_QUEUED;
ret = lttng_dynamic_buffer_set_size(
&client->communication.outbound.buffer, 0);
if (ret) {
+ status = CLIENT_TRANSMISSION_STATUS_ERROR;
goto error;
}
status = CLIENT_TRANSMISSION_STATUS_COMPLETE;
}
-end:
- return status;
+
+ ret = client_handle_transmission_status(client, status, state);
+ if (ret) {
+ goto error;
+ }
+
+ return 0;
error:
- return CLIENT_TRANSMISSION_STATUS_ERROR;
+ return -1;
}
/* Client lock must be acquired by caller. */
.size = sizeof(reply),
};
char buffer[sizeof(msg) + sizeof(reply)];
- enum client_transmission_status transmission_status;
ASSERT_LOCKED(client->lock);
goto error;
}
- transmission_status = client_flush_outgoing_queue(client);
- ret = client_handle_transmission_status(
- client, transmission_status, state);
+ ret = client_flush_outgoing_queue(client, state);
if (ret) {
goto error;
}
enum lttng_notification_channel_status status =
LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
char send_buffer[sizeof(msg_header) + sizeof(handshake_reply)];
- enum client_transmission_status transmission_status;
pthread_mutex_lock(&client->lock);
client->validated = true;
client->communication.active = true;
- transmission_status = client_flush_outgoing_queue(client);
- ret = client_handle_transmission_status(
- client, transmission_status, state);
+ ret = client_flush_outgoing_queue(client, state);
if (ret) {
goto end;
}
{
int ret;
struct notification_client *client;
- enum client_transmission_status transmission_status;
client = get_client_from_socket(socket, state);
if (!client) {
}
pthread_mutex_lock(&client->lock);
- transmission_status = client_flush_outgoing_queue(client);
- ret = client_handle_transmission_status(
- client, transmission_status, state);
+ ret = client_flush_outgoing_queue(client, state);
pthread_mutex_unlock(&client->lock);
if (ret) {
goto end;
}
static
-int client_notification_overflow(struct notification_client *client)
+int client_enqueue_dropped_notification(struct notification_client *client)
{
- int ret = 0;
- const struct lttng_notification_channel_message msg = {
+ int ret;
+ struct lttng_notification_channel_message msg = {
.type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED,
+ .size = 0,
};
ASSERT_LOCKED(client->lock);
- DBG("Dropping notification addressed to client (socket fd = %i)",
- client->socket);
- if (client->communication.outbound.dropped_notification) {
- /*
- * The client already has a "notification dropped" message
- * in its outgoing queue. Nothing to do since all
- * of those messages are coalesced.
- */
- goto end;
- }
-
- client->communication.outbound.dropped_notification = true;
ret = lttng_dynamic_buffer_append(
&client->communication.outbound.buffer, &msg,
sizeof(msg));
- if (ret) {
- PERROR("Failed to enqueue \"dropped notification\" message in client's (socket fd = %i) outgoing queue",
- client->socket);
- }
-end:
return ret;
}
-static int client_handle_transmission_status_wrapper(
- struct notification_client *client,
- enum client_transmission_status status,
- void *user_data)
-{
- return client_handle_transmission_status(client, status,
- (struct notification_thread_state *) user_data);
-}
-
-static
-int send_evaluation_to_clients(const struct lttng_trigger *trigger,
- const struct lttng_evaluation *evaluation,
- struct notification_client_list* client_list,
- struct notification_thread_state *state,
- uid_t object_uid, gid_t object_gid)
-{
- return notification_client_list_send_evaluation(client_list,
- lttng_trigger_get_const_condition(trigger), evaluation,
- lttng_trigger_get_credentials(trigger),
- &(struct lttng_credentials){
- .uid = object_uid, .gid = object_gid},
- client_handle_transmission_status_wrapper, state);
-}
-
/*
* Permission checks relative to notification channel clients are performed
* here. Notice how object, client, and trigger credentials are involved in
* interference from external users (those could, for instance, unregister
* their triggers).
*/
-LTTNG_HIDDEN
-int notification_client_list_send_evaluation(
- struct notification_client_list *client_list,
- const struct lttng_condition *condition,
+static
+int send_evaluation_to_clients(const struct lttng_trigger *trigger,
const struct lttng_evaluation *evaluation,
- const struct lttng_credentials *trigger_creds,
- const struct lttng_credentials *source_object_creds,
- report_client_transmission_result_cb client_report,
- void *user_data)
+ struct notification_client_list* client_list,
+ struct notification_thread_state *state,
+ uid_t object_uid, gid_t object_gid)
{
int ret = 0;
struct lttng_payload msg_payload;
struct notification_client_list_element *client_list_element, *tmp;
const struct lttng_notification notification = {
- .condition = (struct lttng_condition *) condition,
+ .condition = (struct lttng_condition *) lttng_trigger_get_const_condition(trigger),
.evaluation = (struct lttng_evaluation *) evaluation,
};
struct lttng_notification_channel_message msg_header = {
.type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION,
};
+ const struct lttng_credentials *trigger_creds = lttng_trigger_get_credentials(trigger);
lttng_payload_init(&msg_payload);
pthread_mutex_lock(&client_list->lock);
cds_list_for_each_entry_safe(client_list_element, tmp,
&client_list->list, node) {
- enum client_transmission_status transmission_status;
struct notification_client *client =
client_list_element->client;
ret = 0;
pthread_mutex_lock(&client->lock);
- if (source_object_creds) {
- if (client->uid != source_object_creds->uid &&
- client->gid != source_object_creds->gid &&
- client->uid != 0) {
- /*
- * Client is not allowed to monitor this
- * object.
- */
- DBG("[notification-thread] Skipping client at it does not have the object permission to receive notification for this trigger");
- goto unlock_client;
- }
+ if (client->uid != object_uid && client->gid != object_gid &&
+ client->uid != 0) {
+ /* Client is not allowed to monitor this channel. */
+ DBG("[notification-thread] Skipping client at it does not have the object permission to receive notification for this trigger");
+ goto unlock_client;
}
if (client->uid != trigger_creds->uid && client->gid != trigger_creds->gid) {
* notification since the socket spilled-over to the
* queue.
*/
- ret = client_notification_overflow(client);
- if (ret) {
- goto unlock_client;
+ DBG("[notification-thread] Dropping notification addressed to client (socket fd = %i)",
+ client->socket);
+ if (!client->communication.outbound.dropped_notification) {
+ client->communication.outbound.dropped_notification = true;
+ ret = client_enqueue_dropped_notification(
+ client);
+ if (ret) {
+ goto unlock_client;
+ }
}
+ goto unlock_client;
}
ret = lttng_dynamic_buffer_append_buffer(
goto unlock_client;
}
- transmission_status = client_flush_outgoing_queue(client);
- ret = client_report(client, transmission_status, user_data);
+ ret = client_flush_outgoing_queue(client, state);
if (ret) {
goto unlock_client;
}
bool previous_sample_available = false;
struct channel_state_sample previous_sample, latest_sample;
uint64_t previous_session_consumed_total, latest_session_consumed_total;
- struct lttng_credentials channel_creds;
/*
* The monitoring pipe only holds messages smaller than PIPE_BUF,
goto end_unlock;
}
- channel_creds = (typeof(channel_creds)) {
- .uid = channel_info->session_info->uid,
- .gid = channel_info->session_info->gid,
- };
-
trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
channel_triggers_ht_node);
cds_list_for_each_entry(trigger_list_element, &trigger_list->list,
node) {
const struct lttng_condition *condition;
const struct lttng_action *action;
- struct lttng_trigger *trigger;
+ const struct lttng_trigger *trigger;
struct notification_client_list *client_list = NULL;
struct lttng_evaluation *evaluation = NULL;
bool client_list_is_empty;
- enum action_executor_status executor_status;
ret = 0;
trigger = trigger_list_element->trigger;
goto put_list;
}
- /*
- * Ownership of `evaluation` transferred to the action executor
- * no matter the result.
- */
- executor_status = action_executor_enqueue(state->executor,
- trigger, evaluation, &channel_creds,
- client_list);
- evaluation = NULL;
- switch (executor_status) {
- case ACTION_EXECUTOR_STATUS_OK:
- break;
- case ACTION_EXECUTOR_STATUS_ERROR:
- case ACTION_EXECUTOR_STATUS_INVALID:
- /*
- * TODO Add trigger identification (name/id) when
- * it is added to the API.
- */
- ERR("Fatal error occurred while enqueuing action associated with buffer-condition trigger");
- ret = -1;
- goto put_list;
- case ACTION_EXECUTOR_STATUS_OVERFLOW:
- /*
- * TODO Add trigger identification (name/id) when
- * it is added to the API.
- *
- * Not a fatal error.
- */
- WARN("No space left when enqueuing action associated with buffer-condition trigger");
- ret = 0;
- goto put_list;
- default:
- abort();
- }
-
+ /* Dispatch evaluation result to all clients. */
+ ret = send_evaluation_to_clients(trigger_list_element->trigger,
+ evaluation, client_list, state,
+ channel_info->session_info->uid,
+ channel_info->session_info->gid);
+ lttng_evaluation_destroy(evaluation);
put_list:
notification_client_list_put(client_list);
if (caa_unlikely(ret)) {
projects / lttng-tools.git / blobdiff