277fc23e30f22ff4be3d9c93f7b66bd343721be6
[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/compat/poll.h>
17 #include <common/compat/socket.h>
18 #include <common/uuid.h>
19
20 #include "session.h"
21 #include "ust-app.h"
22 #include "notification-thread.h"
23 #include "sessiond-config.h"
24
25 /*
26 * Consumer daemon state which is changed when spawning it, killing it or in
27 * case of a fatal error.
28 */
29 enum consumerd_state {
30 CONSUMER_STARTED = 1,
31 CONSUMER_STOPPED = 2,
32 CONSUMER_ERROR = 3,
33 };
34
35 /* Unique identifier of a session daemon instance. */
36 extern lttng_uuid sessiond_uuid;
37
38 /*
39 * This consumer daemon state is used to validate if a client command will be
40 * able to reach the consumer. If not, the client is informed. For instance,
41 * doing a "lttng start" when the consumer state is set to ERROR will return an
42 * error to the client.
43 *
44 * The following example shows a possible race condition of this scheme:
45 *
46 * consumer thread error happens
47 * client cmd arrives
48 * client cmd checks state -> still OK
49 * consumer thread exit, sets error
50 * client cmd try to talk to consumer
51 * ...
52 *
53 * However, since the consumer is a different daemon, we have no way of making
54 * sure the command will reach it safely even with this state flag. This is why
55 * we consider that up to the state validation during command processing, the
56 * command is safe. After that, we can not guarantee the correctness of the
57 * client request vis-a-vis the consumer.
58 */
59 extern enum consumerd_state ust_consumerd_state;
60 extern enum consumerd_state kernel_consumerd_state;
61
62 extern const char default_home_dir[],
63 default_tracing_group[],
64 default_ust_sock_dir[],
65 default_global_apps_pipe[];
66
67 /* Set in main.c at boot time of the daemon */
68 extern struct lttng_kernel_tracer_version kernel_tracer_version;
69 extern struct lttng_kernel_tracer_abi_version kernel_tracer_abi_version;
70
71 /* Notification thread handle. */
72 extern struct notification_thread_handle *notification_thread_handle;
73
74 /*
75 * This contains extra data needed for processing a command received by the
76 * session daemon from the lttng client.
77 */
78 struct command_ctx {
79 unsigned int lttng_msg_size;
80 struct ltt_session *session;
81 struct lttcomm_lttng_msg *llm;
82 struct lttcomm_session_msg *lsm;
83 lttng_sock_cred creds;
84 };
85
86 struct ust_command {
87 int sock;
88 struct ust_register_msg reg_msg;
89 struct cds_wfcq_node node;
90 };
91
92 /*
93 * Queue used to enqueue UST registration request (ust_command) and synchronized
94 * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
95 */
96 struct ust_cmd_queue {
97 int32_t futex;
98 struct cds_wfcq_head head;
99 struct cds_wfcq_tail tail;
100 };
101
102 /*
103 * This is the wait queue containing wait nodes during the application
104 * registration process.
105 */
106 struct ust_reg_wait_queue {
107 unsigned long count;
108 struct cds_list_head head;
109 };
110
111 /*
112 * Use by the dispatch registration to queue UST command socket to wait for the
113 * notify socket.
114 */
115 struct ust_reg_wait_node {
116 struct ust_app *app;
117 struct cds_list_head head;
118 };
119
120 /*
121 * Used to notify that a hash table needs to be destroyed by dedicated
122 * thread. Required by design because we don't want to move destroy
123 * paths outside of large RCU read-side lock paths, and destroy cannot
124 * be called by call_rcu thread, because it may hang (waiting for
125 * call_rcu completion).
126 */
127 extern int ht_cleanup_pipe[2];
128
129 extern int kernel_poll_pipe[2];
130
131 /*
132 * Populated when the daemon starts with the current page size of the system.
133 * Set in main() with the current page size.
134 */
135 extern long page_size;
136
137 /* Application health monitoring */
138 extern struct health_app *health_sessiond;
139
140 extern struct sessiond_config config;
141
142 extern int ust_consumerd64_fd, ust_consumerd32_fd;
143
144 /* Parent PID for --sig-parent option */
145 extern pid_t ppid;
146 /* Internal parent PID use with daemonize. */
147 extern pid_t child_ppid;
148
149 /* Consumer daemon specific control data. */
150 extern struct consumer_data ustconsumer32_data;
151 extern struct consumer_data ustconsumer64_data;
152 extern struct consumer_data kconsumer_data;
153
154 int sessiond_init_thread_quit_pipe(void);
155 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
156 int sessiond_wait_for_quit_pipe(int timeout_ms);
157 int sessiond_notify_quit_pipe(void);
158 void sessiond_close_quit_pipe(void);
159
160 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
161 void sessiond_signal_parents(void);
162
163 void sessiond_set_client_thread_state(bool running);
164 void sessiond_wait_client_thread_stopped(void);
165
166 void *thread_manage_consumer(void *data);
167
168 #endif /* _LTT_SESSIOND_H */
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