SoW-2019-0002: Dynamic Snapshot
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-internal.h
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8abe313a 1/*
ab5be9fa 2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
8abe313a 3 *
ab5be9fa 4 * SPDX-License-Identifier: GPL-2.0-only
8abe313a 5 *
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6 */
7
8#ifndef NOTIFICATION_THREAD_INTERNAL_H
9#define NOTIFICATION_THREAD_INTERNAL_H
10
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11#include <common/credentials.h>
12#include <lttng/notification/channel-internal.h>
8abe313a 13#include <lttng/ref-internal.h>
1831ae68 14#include <stdbool.h>
8abe313a 15#include <unistd.h>
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16#include <urcu/rculfhash.h>
17#include <urcu/ref.h>
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18
19struct channel_key {
20 uint64_t key;
21 enum lttng_domain_type domain;
22};
23
24struct session_info {
25 struct lttng_ref ref;
26 char *name;
27 uid_t uid;
28 gid_t gid;
29 /*
c7283958 30 * Hashtable containing back-refs (weak) to all channels in this session.
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31 * The hashtable's key is a hash of (struct channel_key) and
32 * the value is of type (struct channel_info *).
33 */
34 struct cds_lfht *channel_infos_ht;
ea9a44f0 35 struct lttng_session_trigger_list *trigger_list;
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36 /* Node in the notification thread state's sessions_ht. */
37 struct cds_lfht_node sessions_ht_node;
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38 /*
39 * Weak reference to the thread state's sessions_ht. Used for removal on
40 * destruction.
41 */
42 struct cds_lfht *sessions_ht;
e8360425 43 uint64_t consumed_data_size;
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44 struct {
45 /* Whether a rotation is ongoing for this session. */
46 bool ongoing;
47 /* Identifier of the currently ongoing rotation. */
48 uint64_t id;
49 } rotation;
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50 /* call_rcu delayed reclaim. */
51 struct rcu_head rcu_node;
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52};
53
54struct channel_info {
55 struct channel_key key;
56 char *name;
57 uint64_t capacity;
58 /*
59 * A channel info holds a reference (lttng_ref) on session_info.
60 * session_info, in return, holds a weak reference to the channel.
61 */
62 struct session_info *session_info;
63 /* Node in the notification thread state's channels_ht. */
64 struct cds_lfht_node channels_ht_node;
65 /* Node in the session_info's channels_ht. */
66 struct cds_lfht_node session_info_channels_ht_node;
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67 /* call_rcu delayed reclaim. */
68 struct rcu_head rcu_node;
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69};
70
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71struct notification_client_list_element {
72 struct notification_client *client;
73 struct cds_list_head node;
74};
75
76/*
77 * Thread safety of notification_client and notification_client_list.
78 *
79 * The notification thread (main thread) and the action executor
80 * interact through client lists. Hence, when the action executor
81 * thread looks-up the list of clients subscribed to a given
82 * condition, it will acquire a reference to the list and lock it
83 * while attempting to communicate with the various clients.
84 *
85 * It is not necessary to reference-count clients as they are guaranteed
86 * to be 'alive' if they are present in a list and that list is locked. Indeed,
87 * removing references to the client from those subscription lists is part of
88 * the work performed on destruction of a client.
89 *
90 * No provision for other access scenarios are taken into account;
91 * this is the bare minimum to make these accesses safe and the
92 * notification thread's state is _not_ "thread-safe" in any general
93 * sense.
94 */
95struct notification_client_list {
96 pthread_mutex_t lock;
97 struct urcu_ref ref;
98 const struct lttng_trigger *trigger;
99 struct cds_list_head list;
100 /* Weak reference to container. */
101 struct cds_lfht *notification_trigger_clients_ht;
102 struct cds_lfht_node notification_trigger_clients_ht_node;
103 /* call_rcu delayed reclaim. */
104 struct rcu_head rcu_node;
105};
106
107struct notification_client {
108 /* Nests within the notification_client_list lock. */
109 pthread_mutex_t lock;
110 notification_client_id id;
111 int socket;
112 /* Client protocol version. */
113 uint8_t major, minor;
114 uid_t uid;
115 gid_t gid;
116 /*
117 * Indicates if the credentials and versions of the client have been
118 * checked.
119 */
120 bool validated;
121 /*
122 * Conditions to which the client's notification channel is subscribed.
123 * List of struct lttng_condition_list_node. The condition member is
124 * owned by the client.
125 */
126 struct cds_list_head condition_list;
127 struct cds_lfht_node client_socket_ht_node;
128 struct cds_lfht_node client_id_ht_node;
129 struct {
130 /*
131 * If a client's communication is inactive, it means that a
132 * fatal error has occurred (could be either a protocol error or
133 * the socket API returned a fatal error). No further
134 * communication should be attempted; the client is queued for
135 * clean-up.
136 */
137 bool active;
138 struct {
139 /*
140 * During the reception of a message, the reception
141 * buffers' "size" is set to contain the current
142 * message's complete payload.
143 */
144 struct lttng_dynamic_buffer buffer;
145 /* Bytes left to receive for the current message. */
146 size_t bytes_to_receive;
147 /* Type of the message being received. */
148 enum lttng_notification_channel_message_type msg_type;
149 /*
150 * Indicates whether or not credentials are expected
151 * from the client.
152 */
153 bool expect_creds;
154 /*
155 * Indicates whether or not credentials were received
156 * from the client.
157 */
158 bool creds_received;
159 /* Only used during credentials reception. */
160 lttng_sock_cred creds;
161 } inbound;
162 struct {
163 /*
164 * Indicates whether or not a notification addressed to
165 * this client was dropped because a command reply was
166 * already buffered.
167 *
168 * A notification is dropped whenever the buffer is not
169 * empty.
170 */
171 bool dropped_notification;
172 /*
173 * Indicates whether or not a command reply is already
174 * buffered. In this case, it means that the client is
175 * not consuming command replies before emitting a new
176 * one. This could be caused by a protocol error or a
177 * misbehaving/malicious client.
178 */
179 bool queued_command_reply;
180 struct lttng_dynamic_buffer buffer;
181 } outbound;
182 } communication;
183 /* call_rcu delayed reclaim. */
184 struct rcu_head rcu_node;
185};
186
187enum client_transmission_status {
188 CLIENT_TRANSMISSION_STATUS_COMPLETE,
189 CLIENT_TRANSMISSION_STATUS_QUEUED,
190 /* Communication failure. */
191 CLIENT_TRANSMISSION_STATUS_FAIL,
192 /* Fatal error. */
193 CLIENT_TRANSMISSION_STATUS_ERROR,
194};
195
196LTTNG_HIDDEN
197bool notification_client_list_get(struct notification_client_list *list);
198
199LTTNG_HIDDEN
200void notification_client_list_put(struct notification_client_list *list);
201
202typedef int (*report_client_transmission_result_cb)(
203 struct notification_client *client,
204 enum client_transmission_status status,
205 void *user_data);
206
207LTTNG_HIDDEN
208int notification_client_list_send_evaluation(
209 struct notification_client_list *list,
210 const struct lttng_condition *condition,
211 const struct lttng_evaluation *evaluation,
212 const struct lttng_credentials *trigger_creds,
213 const struct lttng_credentials *source_object_creds,
214 report_client_transmission_result_cb client_report,
215 void *user_data);
216
8abe313a 217#endif /* NOTIFICATION_THREAD_INTERNAL_H */
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