Fix: relayd: rotation failure for multi-domain session
[lttng-tools.git] / src / bin / lttng-sessiond / lttng-sessiond.h
1 /*
2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
3 * Copyright (C) 2013 Raphaƫl Beamonte <raphael.beamonte@gmail.com>
4 *
5 * SPDX-License-Identifier: GPL-2.0-only
6 *
7 */
8
9 #ifndef _LTT_SESSIOND_H
10 #define _LTT_SESSIOND_H
11
12 #include <urcu.h>
13 #include <urcu/wfcqueue.h>
14
15 #include <common/sessiond-comm/sessiond-comm.h>
16 #include <common/payload.h>
17 #include <common/compat/poll.h>
18 #include <common/compat/socket.h>
19 #include <common/uuid.h>
20
21 #include "session.h"
22 #include "ust-app.h"
23 #include "notification-thread.h"
24 #include "sessiond-config.h"
25
26 /*
27 * Consumer daemon state which is changed when spawning it, killing it or in
28 * case of a fatal error.
29 */
30 enum consumerd_state {
31 CONSUMER_STARTED = 1,
32 CONSUMER_STOPPED = 2,
33 CONSUMER_ERROR = 3,
34 };
35
36 /* Unique identifier of a session daemon instance. */
37 extern lttng_uuid the_sessiond_uuid;
38
39 /*
40 * This consumer daemon state is used to validate if a client command will be
41 * able to reach the consumer. If not, the client is informed. For instance,
42 * doing a "lttng start" when the consumer state is set to ERROR will return an
43 * error to the client.
44 *
45 * The following example shows a possible race condition of this scheme:
46 *
47 * consumer thread error happens
48 * client cmd arrives
49 * client cmd checks state -> still OK
50 * consumer thread exit, sets error
51 * client cmd try to talk to consumer
52 * ...
53 *
54 * However, since the consumer is a different daemon, we have no way of making
55 * sure the command will reach it safely even with this state flag. This is why
56 * we consider that up to the state validation during command processing, the
57 * command is safe. After that, we can not guarantee the correctness of the
58 * client request vis-a-vis the consumer.
59 */
60 extern enum consumerd_state the_ust_consumerd_state;
61 extern enum consumerd_state the_kernel_consumerd_state;
62
63 /* Set in main.c at boot time of the daemon */
64 extern struct lttng_kernel_abi_tracer_version the_kernel_tracer_version;
65 extern struct lttng_kernel_abi_tracer_abi_version the_kernel_tracer_abi_version;
66
67 /* Notification thread handle. */
68 extern struct notification_thread_handle *the_notification_thread_handle;
69
70 /*
71 * This contains extra data needed for processing a command received by the
72 * session daemon from the lttng client.
73 */
74 struct command_ctx {
75 unsigned int lttng_msg_size;
76 struct ltt_session *session;
77 /* Input message */
78 struct lttcomm_session_msg lsm;
79 /* Reply content, starts with an lttcomm_lttng_msg header. */
80 struct lttng_payload reply_payload;
81 lttng_sock_cred creds;
82 };
83
84 struct ust_command {
85 int sock;
86 struct ust_register_msg reg_msg;
87 struct cds_wfcq_node node;
88 };
89
90 /*
91 * Queue used to enqueue UST registration request (ust_command) and synchronized
92 * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
93 */
94 struct ust_cmd_queue {
95 int32_t futex;
96 struct cds_wfcq_head head;
97 struct cds_wfcq_tail tail;
98 };
99
100 /*
101 * This is the wait queue containing wait nodes during the application
102 * registration process.
103 */
104 struct ust_reg_wait_queue {
105 unsigned long count;
106 struct cds_list_head head;
107 };
108
109 /*
110 * Use by the dispatch registration to queue UST command socket to wait for the
111 * notify socket.
112 */
113 struct ust_reg_wait_node {
114 struct ust_app *app;
115 struct cds_list_head head;
116 };
117
118 /*
119 * Used to notify that a hash table needs to be destroyed by dedicated
120 * thread. Required by design because we don't want to move destroy
121 * paths outside of large RCU read-side lock paths, and destroy cannot
122 * be called by call_rcu thread, because it may hang (waiting for
123 * call_rcu completion).
124 */
125 extern int the_ht_cleanup_pipe[2];
126
127 extern int the_kernel_poll_pipe[2];
128
129 /*
130 * Populated when the daemon starts with the current page size of the system.
131 * Set in main() with the current page size.
132 */
133 extern long the_page_size;
134
135 /* Application health monitoring */
136 extern struct health_app *the_health_sessiond;
137
138 extern struct sessiond_config the_config;
139
140 extern int the_ust_consumerd64_fd, the_ust_consumerd32_fd;
141
142 /* Parent PID for --sig-parent option */
143 extern pid_t the_ppid;
144 /* Internal parent PID use with daemonize. */
145 extern pid_t the_child_ppid;
146
147 /* Consumer daemon specific control data. */
148 extern struct consumer_data the_ustconsumer32_data;
149 extern struct consumer_data the_ustconsumer64_data;
150 extern struct consumer_data the_kconsumer_data;
151
152 int sessiond_init_thread_quit_pipe(void);
153 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
154 int sessiond_wait_for_quit_pipe(int timeout_ms);
155 int sessiond_notify_quit_pipe(void);
156 void sessiond_close_quit_pipe(void);
157
158 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
159 void sessiond_signal_parents(void);
160
161 void sessiond_set_client_thread_state(bool running);
162 void sessiond_wait_client_thread_stopped(void);
163
164 void *thread_manage_consumer(void *data);
165
166 #endif /* _LTT_SESSIOND_H */
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