2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
8 #ifndef NOTIFICATION_THREAD_INTERNAL_H
9 #define NOTIFICATION_THREAD_INTERNAL_H
11 #include <common/compat/socket.h>
12 #include <common/credentials.h>
13 #include <common/payload.h>
14 #include <lttng/notification/channel-internal.h>
15 #include <lttng/ref-internal.h>
18 #include <urcu/rculfhash.h>
20 #include <urcu/call-rcu.h>
21 #include "notification-thread.h"
23 struct lttng_evaluation
;
24 struct notification_thread_handle
;
28 enum lttng_domain_type domain
;
37 * Hashtable containing back-refs (weak) to all channels in this session.
38 * The hashtable's key is a hash of (struct channel_key) and
39 * the value is of type (struct channel_info *).
41 struct cds_lfht
*channel_infos_ht
;
42 struct lttng_session_trigger_list
*trigger_list
;
43 /* Node in the notification thread state's sessions_ht. */
44 struct cds_lfht_node sessions_ht_node
;
46 * Weak reference to the thread state's sessions_ht. Used for removal on
49 struct cds_lfht
*sessions_ht
;
50 uint64_t consumed_data_size
;
52 /* Whether a rotation is ongoing for this session. */
54 /* Identifier of the currently ongoing rotation. */
57 /* call_rcu delayed reclaim. */
58 struct rcu_head rcu_node
;
62 struct channel_key key
;
66 * A channel info holds a reference (lttng_ref) on session_info.
67 * session_info, in return, holds a weak reference to the channel.
69 struct session_info
*session_info
;
70 /* Node in the notification thread state's channels_ht. */
71 struct cds_lfht_node channels_ht_node
;
72 /* Node in the session_info's channels_ht. */
73 struct cds_lfht_node session_info_channels_ht_node
;
74 /* call_rcu delayed reclaim. */
75 struct rcu_head rcu_node
;
78 struct notification_client_list_element
{
79 struct notification_client
*client
;
80 struct cds_list_head node
;
84 * Thread safety of notification_client and notification_client_list.
86 * The notification thread (main thread) and the action executor
87 * interact through client lists. Hence, when the action executor
88 * thread looks-up the list of clients subscribed to a given
89 * condition, it will acquire a reference to the list and lock it
90 * while attempting to communicate with the various clients.
92 * It is not necessary to reference-count clients as they are guaranteed
93 * to be 'alive' if they are present in a list and that list is locked. Indeed,
94 * removing references to the client from those subscription lists is part of
95 * the work performed on destruction of a client.
97 * No provision for other access scenarios are taken into account;
98 * this is the bare minimum to make these accesses safe and the
99 * notification thread's state is _not_ "thread-safe" in any general
102 struct notification_client_list
{
103 pthread_mutex_t lock
;
105 const struct lttng_trigger
*trigger
;
106 struct cds_list_head list
;
107 /* Weak reference to container. */
108 struct cds_lfht
*notification_trigger_clients_ht
;
109 struct cds_lfht_node notification_trigger_clients_ht_node
;
110 /* call_rcu delayed reclaim. */
111 struct rcu_head rcu_node
;
114 struct notification_client
{
116 * Nests within the notification_client_list lock.
118 * Protects the outbound communication and the active flag which
119 * is used by both the notification and action executor threads.
121 * The remaining fields of the object can be used without any
122 * synchronization as they are either immutable (id, creds, version) or
123 * only accessed by the notification thread.
125 pthread_mutex_t lock
;
126 notification_client_id id
;
128 /* Client protocol version. */
129 uint8_t major
, minor
;
133 * Indicates if the credentials and versions of the client have been
138 * Conditions to which the client's notification channel is subscribed.
139 * List of struct lttng_condition_list_node. The condition member is
140 * owned by the client.
142 struct cds_list_head condition_list
;
143 struct cds_lfht_node client_socket_ht_node
;
144 struct cds_lfht_node client_id_ht_node
;
147 * If a client's communication is inactive, it means that a
148 * fatal error has occurred (could be either a protocol error or
149 * the socket API returned a fatal error). No further
150 * communication should be attempted; the client is queued for
156 * During the reception of a message, the reception
157 * buffers' "size" is set to contain the current
158 * message's complete payload.
160 struct lttng_payload payload
;
161 /* Bytes left to receive for the current message. */
162 size_t bytes_to_receive
;
163 /* FDs left to receive for the current message. */
165 /* Type of the message being received. */
166 enum lttng_notification_channel_message_type msg_type
;
168 * Indicates whether or not credentials are expected
173 * Indicates whether or not credentials were received
177 /* Only used during credentials reception. */
178 lttng_sock_cred creds
;
182 * Indicates whether or not a notification addressed to
183 * this client was dropped because a command reply was
186 * A notification is dropped whenever the buffer is not
189 bool dropped_notification
;
191 * Indicates whether or not a command reply is already
192 * buffered. In this case, it means that the client is
193 * not consuming command replies before emitting a new
194 * one. This could be caused by a protocol error or a
195 * misbehaving/malicious client.
197 bool queued_command_reply
;
198 struct lttng_payload payload
;
201 /* call_rcu delayed reclaim. */
202 struct rcu_head rcu_node
;
205 enum client_transmission_status
{
206 CLIENT_TRANSMISSION_STATUS_COMPLETE
,
207 CLIENT_TRANSMISSION_STATUS_QUEUED
,
208 /* Communication failure. */
209 CLIENT_TRANSMISSION_STATUS_FAIL
,
211 CLIENT_TRANSMISSION_STATUS_ERROR
,
215 bool notification_client_list_get(struct notification_client_list
*list
);
218 void notification_client_list_put(struct notification_client_list
*list
);
220 /* Only returns a non-zero value if a fatal error occurred. */
221 typedef int (*report_client_transmission_result_cb
)(
222 struct notification_client
*client
,
223 enum client_transmission_status status
,
227 int notification_client_list_send_evaluation(
228 struct notification_client_list
*list
,
229 const struct lttng_condition
*condition
,
230 const struct lttng_evaluation
*evaluation
,
231 const struct lttng_credentials
*trigger_creds
,
232 const struct lttng_credentials
*source_object_creds
,
233 report_client_transmission_result_cb client_report
,
237 int notification_thread_client_communication_update(
238 struct notification_thread_handle
*handle
,
239 notification_client_id id
,
240 enum client_transmission_status transmission_status
);
242 #endif /* NOTIFICATION_THREAD_INTERNAL_H */