#include <urcu/list.h>
#include <urcu/rculfhash.h>
-/**
- * This thread maintains an internal state associating clients and triggers.
- *
- * In order to speed-up and simplify queries, hash tables providing the
- * following associations are maintained:
- *
- * - client_socket_ht: associate a client's socket (fd) to its "struct client"
- * This hash table owns the "struct client" which must thus be
- * disposed-of on removal from the hash table.
- *
- * - channel_triggers_ht:
- * associates a channel key to a list of
- * struct lttng_trigger_list_nodes. The triggers in this list are
- * those that have conditions that apply to this channel.
- * This hash table owns the list, but not the triggers themselves.
- *
- * - channel_state_ht:
- * associates a pair (channel key, channel domain) to its last
- * sampled state received from the consumer daemon
- * (struct channel_state).
- * This previous sample is kept to implement edge-triggered
- * conditions as we need to detect the state transitions.
- * This hash table owns the channel state.
- *
- * - notification_trigger_clients_ht:
- * associates notification-emitting triggers to clients
- * (struct notification_client_list) subscribed to those
- * conditions.
- * The condition's hash and match functions are used directly since
- * all triggers in this hash table have the "notify" action.
- * This hash table holds no ownership.
- *
- * - channels_ht:
- * associates a channel_key to a struct channel_info. The hash table
- * holds the ownership of the struct channel_info.
- *
- * - triggers_ht:
- * associated a condition to a struct lttng_trigger_ht_element.
- * The hash table holds the ownership of the
- * lttng_trigger_ht_elements along with the triggers themselves.
- *
- * The thread reacts to the following internal events:
- * 1) creation of a tracing channel,
- * 2) destruction of a tracing channel,
- * 3) registration of a trigger,
- * 4) unregistration of a trigger,
- * 5) reception of a channel monitor sample from the consumer daemon.
- *
- * Events specific to notification-emitting triggers:
- * 6) connection of a notification client,
- * 7) disconnection of a notification client,
- * 8) subscription of a client to a conditions' notifications,
- * 9) unsubscription of a client from a conditions' notifications,
- *
- *
- * 1) Creation of a tracing channel
- * - notification_trigger_clients_ht is traversed to identify
- * triggers which apply to this new channel,
- * - triggers identified are added to the channel_triggers_ht.
- * - add channel to channels_ht
- *
- * 2) Destruction of a tracing channel
- * - remove entry from channel_triggers_ht, releasing the list wrapper and
- * elements,
- * - remove entry from the channel_state_ht.
- * - remove channel from channels_ht
- *
- * 3) Registration of a trigger
- * - if the trigger's action is of type "notify",
- * - traverse the list of conditions of every client to build a list of
- * clients which have to be notified when this trigger's condition is met,
- * - add list of clients (even if it is empty) to the
- * notification_trigger_clients_ht,
- * - add trigger to channel_triggers_ht (if applicable),
- * - add trigger to triggers_ht
- *
- * 4) Unregistration of a trigger
- * - if the trigger's action is of type "notify",
- * - remove the trigger from the notification_trigger_clients_ht,
- * - remove trigger from channel_triggers_ht (if applicable),
- * - remove trigger from triggers_ht
- *
- * 5) Reception of a channel monitor sample from the consumer daemon
- * - evaluate the conditions associated with the triggers found in
- * the channel_triggers_ht,
- * - if a condition evaluates to "true" and the condition is of type
- * "notify", query the notification_trigger_clients_ht and send
- * a notification to the clients.
- *
- * 6) Connection of a client
- * - add client socket to the client_socket_ht.
- *
- * 7) Disconnection of a client
- * - remove client socket from the client_socket_ht,
- * - traverse all conditions to which the client is subscribed and remove
- * the client from the notification_trigger_clients_ht.
- *
- * 8) Subscription of a client to a condition's notifications
- * - Add the condition to the client's list of subscribed conditions,
- * - Look-up notification_trigger_clients_ht and add the client to
- * list of clients.
- *
- * 9) Unsubscription of a client to a condition's notifications
- * - Remove the condition from the client's list of subscribed conditions,
- * - Look-up notification_trigger_clients_ht and remove the client
- * from the list of clients.
- */
-
/*
* Destroy the thread data previously created by the init function.
*/
projects / lttng-tools.git / blobdiff