Fix: sessiond: erroneous user check logic in session_access_ok
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread.h
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ab0ee2ca 1/*
ab5be9fa 2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
ab0ee2ca 3 *
ab5be9fa 4 * SPDX-License-Identifier: GPL-2.0-only
ab0ee2ca 5 *
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6 */
7
8#ifndef NOTIFICATION_THREAD_H
9#define NOTIFICATION_THREAD_H
10
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11#include "action-executor.h"
12#include "thread.h"
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13#include <common/compat/poll.h>
14#include <common/hashtable/hashtable.h>
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15#include <common/pipe.h>
16#include <lttng/trigger/trigger.h>
ab0ee2ca 17#include <pthread.h>
90936dcf 18#include <semaphore.h>
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19#include <urcu.h>
20#include <urcu/list.h>
21#include <urcu/rculfhash.h>
ab0ee2ca 22
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23
24typedef uint64_t notification_client_id;
25
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26struct notification_thread_handle {
27 /*
28 * Queue of struct notification command.
814b4934 29 * event_pipe must be WRITE(2) to signal that a new command
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30 * has been enqueued.
31 */
32 struct {
814b4934 33 struct lttng_pipe *event_pipe;
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34 struct cds_list_head list;
35 pthread_mutex_t lock;
36 } cmd_queue;
37 /*
38 * Read side of pipes used to receive channel status info collected
39 * by the various consumer daemons.
40 */
41 struct {
42 int ust32_consumer;
43 int ust64_consumer;
44 int kernel_consumer;
45 } channel_monitoring_pipes;
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46 /* Used to wait for the launch of the notification thread. */
47 sem_t ready;
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48};
49
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50/**
51 * This thread maintains an internal state associating clients and triggers.
52 *
53 * In order to speed-up and simplify queries, hash tables providing the
54 * following associations are maintained:
55 *
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56 * - client_socket_ht: associate a client's socket (fd) to its
57 * "struct notification_client".
58 * This hash table owns the "struct notification_client" which must
59 * thus be disposed-of on removal from the hash table.
60 *
61 * - client_id_ht: associate a client's id to its "struct notification_client"
62 * This hash table holds a _weak_ reference to the
63 * "struct notification_client".
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64 *
65 * - channel_triggers_ht:
66 * associates a channel key to a list of
67 * struct lttng_trigger_list_nodes. The triggers in this list are
ea9a44f0 68 * those that have conditions that apply to a particular channel.
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69 * A channel entry is only created when a channel is added; the
70 * list of triggers applying to such a channel is built at that
71 * moment.
72 * This hash table owns the list, but not the triggers themselves.
73 *
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74 * - session_triggers_ht:
75 * associates a session name to a list of
76 * struct lttng_trigger_list_nodes. The triggers in this list are
77 * those that have conditions that apply to a particular session.
78 * A session entry is only created when a session is created; the
79 * list of triggers applying to this new session is built at that
80 * moment. This happens at the time of creation of a session_info.
81 * Likewise, the list is destroyed at the time of the session_info's
82 * destruction.
83 *
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84 * - channel_state_ht:
85 * associates a pair (channel key, channel domain) to its last
86 * sampled state received from the consumer daemon
87 * (struct channel_state).
88 * This previous sample is kept to implement edge-triggered
89 * conditions as we need to detect the state transitions.
90 * This hash table owns the channel state.
91 *
92 * - notification_trigger_clients_ht:
93 * associates notification-emitting triggers to clients
94 * (struct notification_client_list) subscribed to those
95 * conditions.
96 * The condition's hash and match functions are used directly since
97 * all triggers in this hash table have the "notify" action.
98 * This hash table holds no ownership.
99 *
100 * - channels_ht:
101 * associates a channel_key to a struct channel_info. The hash table
102 * holds the ownership of the struct channel_info.
103 *
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104 * - sessions_ht:
105 * associates a session_name (hash) to a struct session_info. The
106 * hash table holds no ownership of the struct session_info;
107 * the session_info structure is owned by the session's various
108 * channels through their struct channel_info (ref-counting is used).
109 *
74df9916 110 * - triggers_ht:
50ca7858 111 * associates a condition to a struct lttng_trigger_ht_element.
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112 * The hash table holds the ownership of the
113 * lttng_trigger_ht_elements along with the triggers themselves.
114 *
115 * The thread reacts to the following internal events:
116 * 1) creation of a tracing channel,
117 * 2) destruction of a tracing channel,
118 * 3) registration of a trigger,
119 * 4) unregistration of a trigger,
120 * 5) reception of a channel monitor sample from the consumer daemon.
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121 * 6) Session rotation ongoing
122 * 7) Session rotation completed
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123 *
124 * Events specific to notification-emitting triggers:
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125 * 8) connection of a notification client,
126 * 9) disconnection of a notification client,
127 * 10) subscription of a client to a conditions' notifications,
128 * 11) unsubscription of a client from a conditions' notifications,
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129 *
130 *
131 * 1) Creation of a tracing channel
132 * - notification_trigger_clients_ht is traversed to identify
133 * triggers which apply to this new channel,
8abe313a 134 * - triggers identified are added to the channel_triggers_ht.
74df9916 135 * - add channel to channels_ht
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136 * - if it is the first channel of a session, a session_info is created and
137 * added to the sessions_ht. A list of the triggers associated with that
138 * session is built, and it is added to session_triggers_ht.
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139 *
140 * 2) Destruction of a tracing channel
141 * - remove entry from channel_triggers_ht, releasing the list wrapper and
142 * elements,
143 * - remove entry from the channel_state_ht.
144 * - remove channel from channels_ht
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145 * - if it was the last known channel of a session, the session_info
146 * structure is torndown, which in return destroys the list of triggers
147 * applying to that session.
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148 *
149 * 3) Registration of a trigger
150 * - if the trigger's action is of type "notify",
151 * - traverse the list of conditions of every client to build a list of
152 * clients which have to be notified when this trigger's condition is met,
153 * - add list of clients (even if it is empty) to the
154 * notification_trigger_clients_ht,
155 * - add trigger to channel_triggers_ht (if applicable),
ea9a44f0 156 * - add trigger to session_triggers_ht (if applicable),
74df9916 157 * - add trigger to triggers_ht
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158 * - evaluate the trigger's condition right away to react if that condition
159 * is true from the beginning.
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160 *
161 * 4) Unregistration of a trigger
162 * - if the trigger's action is of type "notify",
163 * - remove the trigger from the notification_trigger_clients_ht,
164 * - remove trigger from channel_triggers_ht (if applicable),
ea9a44f0 165 * - remove trigger from session_triggers_ht (if applicable),
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166 * - remove trigger from triggers_ht
167 *
168 * 5) Reception of a channel monitor sample from the consumer daemon
169 * - evaluate the conditions associated with the triggers found in
170 * the channel_triggers_ht,
171 * - if a condition evaluates to "true" and the condition is of type
172 * "notify", query the notification_trigger_clients_ht and send
173 * a notification to the clients.
174 *
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175 * 6) Session rotation ongoing
176 *
177 * 7) Session rotation completed
178 *
179 * 8) Connection of a client
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180 * - add client socket to the client_socket_ht,
181 * - add client socket to the client_id_ht.
74df9916 182 *
51eab943 183 * 9) Disconnection of a client
ac1889bf 184 * - remove client socket from the client_id_ht,
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185 * - remove client socket from the client_socket_ht,
186 * - traverse all conditions to which the client is subscribed and remove
187 * the client from the notification_trigger_clients_ht.
188 *
51eab943 189 * 10) Subscription of a client to a condition's notifications
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190 * - Add the condition to the client's list of subscribed conditions,
191 * - Look-up notification_trigger_clients_ht and add the client to
192 * list of clients.
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193 * - Evaluate the condition for the client that subscribed if the trigger
194 * was already registered.
74df9916 195 *
51eab943 196 * 11) Unsubscription of a client to a condition's notifications
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197 * - Remove the condition from the client's list of subscribed conditions,
198 * - Look-up notification_trigger_clients_ht and remove the client
199 * from the list of clients.
200 */
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201struct notification_thread_state {
202 int notification_channel_socket;
203 struct lttng_poll_event events;
204 struct cds_lfht *client_socket_ht;
ac1889bf 205 struct cds_lfht *client_id_ht;
ab0ee2ca 206 struct cds_lfht *channel_triggers_ht;
ea9a44f0 207 struct cds_lfht *session_triggers_ht;
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208 struct cds_lfht *channel_state_ht;
209 struct cds_lfht *notification_trigger_clients_ht;
210 struct cds_lfht *channels_ht;
8abe313a 211 struct cds_lfht *sessions_ht;
ab0ee2ca 212 struct cds_lfht *triggers_ht;
ac1889bf 213 notification_client_id next_notification_client_id;
d1ba29d2 214 struct action_executor *executor;
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215};
216
217/* notification_thread_data takes ownership of the channel monitor pipes. */
218struct notification_thread_handle *notification_thread_handle_create(
219 struct lttng_pipe *ust32_channel_monitor_pipe,
220 struct lttng_pipe *ust64_channel_monitor_pipe,
c8a9de5a 221 struct lttng_pipe *kernel_channel_monitor_pipe);
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222void notification_thread_handle_destroy(
223 struct notification_thread_handle *handle);
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224struct lttng_thread *launch_notification_thread(
225 struct notification_thread_handle *handle);
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226
227#endif /* NOTIFICATION_THREAD_H */
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