X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fnotification-thread-internal.h;h=e36180fb6af634ef4e23c6f1ad7aba45bb3017d1;hp=b278f83d32fbf5fcaaaec646b77075bb6b59df30;hb=6c24d3fd5ade8231445e720c174afe3da4210179;hpb=dd877ea65a8db6b9abcffec9162695059ced90f7 diff --git a/src/bin/lttng-sessiond/notification-thread-internal.h b/src/bin/lttng-sessiond/notification-thread-internal.h index b278f83d3..e36180fb6 100644 --- a/src/bin/lttng-sessiond/notification-thread-internal.h +++ b/src/bin/lttng-sessiond/notification-thread-internal.h @@ -8,9 +8,19 @@ #ifndef NOTIFICATION_THREAD_INTERNAL_H #define NOTIFICATION_THREAD_INTERNAL_H +#include +#include +#include #include -#include +#include #include +#include +#include +#include +#include "notification-thread.h" + +struct lttng_evaluation; +struct notification_thread_handle; struct channel_key { uint64_t key; @@ -64,6 +74,131 @@ struct channel_info { struct rcu_head rcu_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. + * + * Protects the outbound communication and the active flag which + * is used by both the notification and action executor threads. + * + * The remaining fields of the object can be used without any + * synchronization as they are either immutable (id, creds, version) or + * only accessed by the notification thread. + */ + 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; +}; + enum client_transmission_status { CLIENT_TRANSMISSION_STATUS_COMPLETE, CLIENT_TRANSMISSION_STATUS_QUEUED, @@ -72,4 +207,33 @@ enum client_transmission_status { /* Fatal error. */ CLIENT_TRANSMISSION_STATUS_ERROR, }; + +LTTNG_HIDDEN +bool notification_client_list_get(struct notification_client_list *list); + +LTTNG_HIDDEN +void notification_client_list_put(struct notification_client_list *list); + +/* Only returns a non-zero value if a fatal error occurred. */ +typedef int (*report_client_transmission_result_cb)( + struct notification_client *client, + enum client_transmission_status status, + void *user_data); + +LTTNG_HIDDEN +int notification_client_list_send_evaluation( + struct notification_client_list *list, + const struct lttng_condition *condition, + 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); + +LTTNG_HIDDEN +int notification_thread_client_communication_update( + struct notification_thread_handle *handle, + notification_client_id id, + enum client_transmission_status transmission_status); + #endif /* NOTIFICATION_THREAD_INTERNAL_H */