SoW-2020-0002: Trace Hit Counters: trigger error reporting integration
[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 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 ust_consumerd_state;
61 extern enum consumerd_state kernel_consumerd_state;
62
63 extern const char default_home_dir[],
64 default_tracing_group[],
65 default_ust_sock_dir[],
66 default_global_apps_pipe[];
67
68 /* Set in main.c at boot time of the daemon */
69 extern struct lttng_kernel_tracer_version kernel_tracer_version;
70 extern struct lttng_kernel_tracer_abi_version kernel_tracer_abi_version;
71
72 /* Notification thread handle. */
73 extern struct notification_thread_handle *notification_thread_handle;
74 extern pthread_mutex_t notification_trigger_tokens_ht_lock;
75
76 /*
77 * This contains extra data needed for processing a command received by the
78 * session daemon from the lttng client.
79 */
80 struct command_ctx {
81 unsigned int lttng_msg_size;
82 struct ltt_session *session;
83 /* Input message */
84 struct lttcomm_session_msg lsm;
85 /* Reply content, starts with an lttcomm_lttng_msg header. */
86 struct lttng_payload reply_payload;
87 lttng_sock_cred creds;
88 };
89
90 struct ust_command {
91 int sock;
92 struct ust_register_msg reg_msg;
93 struct cds_wfcq_node node;
94 };
95
96 /*
97 * Queue used to enqueue UST registration request (ust_command) and synchronized
98 * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
99 */
100 struct ust_cmd_queue {
101 int32_t futex;
102 struct cds_wfcq_head head;
103 struct cds_wfcq_tail tail;
104 };
105
106 /*
107 * This is the wait queue containing wait nodes during the application
108 * registration process.
109 */
110 struct ust_reg_wait_queue {
111 unsigned long count;
112 struct cds_list_head head;
113 };
114
115 /*
116 * Use by the dispatch registration to queue UST command socket to wait for the
117 * notify socket.
118 */
119 struct ust_reg_wait_node {
120 struct ust_app *app;
121 struct cds_list_head head;
122 };
123
124 /*
125 * Used to notify that a hash table needs to be destroyed by dedicated
126 * thread. Required by design because we don't want to move destroy
127 * paths outside of large RCU read-side lock paths, and destroy cannot
128 * be called by call_rcu thread, because it may hang (waiting for
129 * call_rcu completion).
130 */
131 extern int ht_cleanup_pipe[2];
132
133 extern int kernel_poll_pipe[2];
134
135 /*
136 * Populated when the daemon starts with the current page size of the system.
137 * Set in main() with the current page size.
138 */
139 extern long page_size;
140
141 /* Application health monitoring */
142 extern struct health_app *health_sessiond;
143
144 extern struct sessiond_config config;
145
146 extern int ust_consumerd64_fd, ust_consumerd32_fd;
147
148 /* Parent PID for --sig-parent option */
149 extern pid_t ppid;
150 /* Internal parent PID use with daemonize. */
151 extern pid_t child_ppid;
152
153 /* Consumer daemon specific control data. */
154 extern struct consumer_data ustconsumer32_data;
155 extern struct consumer_data ustconsumer64_data;
156 extern struct consumer_data kconsumer_data;
157
158 int sessiond_init_thread_quit_pipe(void);
159 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
160 int sessiond_wait_for_quit_pipe(int timeout_ms);
161 int sessiond_notify_quit_pipe(void);
162 void sessiond_close_quit_pipe(void);
163
164 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
165 void sessiond_signal_parents(void);
166
167 void sessiond_set_client_thread_state(bool running);
168 void sessiond_wait_client_thread_stopped(void);
169
170 void *thread_manage_consumer(void *data);
171
172 #endif /* _LTT_SESSIOND_H */
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