src/bin/lttng-sessiond/lttng-sessiond.h

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2013 Raphaël 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 extern pthread_mutex_t notification_trigger_tokens_ht_lock;
  74
  75 /*
  76  * This contains extra data needed for processing a command received by the
  77  * session daemon from the lttng client.
  78  */
  79 struct command_ctx {
  80         unsigned int lttng_msg_size;
  81         struct ltt_session *session;
  82         struct lttcomm_lttng_msg *llm;
  83         struct lttcomm_session_msg *lsm;
  84         lttng_sock_cred creds;
  85 };
  86
  87 struct ust_command {
  88         int sock;
  89         struct ust_register_msg reg_msg;
  90         struct cds_wfcq_node node;
  91 };
  92
  93 /*
  94  * Queue used to enqueue UST registration request (ust_command) and synchronized
  95  * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
  96  */
  97 struct ust_cmd_queue {
  98         int32_t futex;
  99         struct cds_wfcq_head head;
 100         struct cds_wfcq_tail tail;
 101 };
 102
 103 /*
 104  * This is the wait queue containing wait nodes during the application
 105  * registration process.
 106  */
 107 struct ust_reg_wait_queue {
 108         unsigned long count;
 109         struct cds_list_head head;
 110 };
 111
 112 /*
 113  * Use by the dispatch registration to queue UST command socket to wait for the
 114  * notify socket.
 115  */
 116 struct ust_reg_wait_node {
 117         struct ust_app *app;
 118         struct cds_list_head head;
 119 };
 120
 121 /*
 122  * Used to notify that a hash table needs to be destroyed by dedicated
 123  * thread. Required by design because we don't want to move destroy
 124  * paths outside of large RCU read-side lock paths, and destroy cannot
 125  * be called by call_rcu thread, because it may hang (waiting for
 126  * call_rcu completion).
 127  */
 128 extern int ht_cleanup_pipe[2];
 129
 130 extern int kernel_poll_pipe[2];
 131
 132 /*
 133  * Populated when the daemon starts with the current page size of the system.
 134  * Set in main() with the current page size.
 135  */
 136 extern long page_size;
 137
 138 /* Application health monitoring */
 139 extern struct health_app *health_sessiond;
 140
 141 extern struct sessiond_config config;
 142
 143 extern int ust_consumerd64_fd, ust_consumerd32_fd;
 144
 145 /* Parent PID for --sig-parent option */
 146 extern pid_t ppid;
 147 /* Internal parent PID use with daemonize. */
 148 extern pid_t child_ppid;
 149
 150 /* Consumer daemon specific control data. */
 151 extern struct consumer_data ustconsumer32_data;
 152 extern struct consumer_data ustconsumer64_data;
 153 extern struct consumer_data kconsumer_data;
 154
 155 int sessiond_init_thread_quit_pipe(void);
 156 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
 157 int sessiond_wait_for_quit_pipe(int timeout_ms);
 158 int sessiond_notify_quit_pipe(void);
 159 void sessiond_close_quit_pipe(void);
 160
 161 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 162 void sessiond_signal_parents(void);
 163
 164 void sessiond_set_client_thread_state(bool running);
 165 void sessiond_wait_client_thread_stopped(void);
 166
 167 void *thread_manage_consumer(void *data);
 168
 169 #endif /* _LTT_SESSIOND_H */