src/bin/lttng-sessiond/lttng-sessiond.hpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   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 "notification-thread.hpp"
  13 #include "rotation-thread.hpp"
  14 #include "session.hpp"
  15 #include "sessiond-config.hpp"
  16 #include "ust-app.hpp"
  17
  18 #include <common/compat/poll.hpp>
  19 #include <common/compat/socket.hpp>
  20 #include <common/payload.hpp>
  21 #include <common/sessiond-comm/sessiond-comm.hpp>
  22 #include <common/uuid.hpp>
  23
  24 #include <urcu.h>
  25 #include <urcu/wfcqueue.h>
  26
  27 /*
  28  * Consumer daemon state which is changed when spawning it, killing it or in
  29  * case of a fatal error.
  30  */
  31 enum consumerd_state {
  32         CONSUMER_STARTED = 1,
  33         CONSUMER_STOPPED = 2,
  34         CONSUMER_ERROR = 3,
  35 };
  36
  37 /* Unique identifier of a session daemon instance. */
  38 extern lttng_uuid the_sessiond_uuid;
  39
  40 /*
  41  * This consumer daemon state is used to validate if a client command will be
  42  * able to reach the consumer. If not, the client is informed. For instance,
  43  * doing a "lttng start" when the consumer state is set to ERROR will return an
  44  * error to the client.
  45  *
  46  * The following example shows a possible race condition of this scheme:
  47  *
  48  * consumer thread error happens
  49  *                                    client cmd arrives
  50  *                                    client cmd checks state -> still OK
  51  * consumer thread exit, sets error
  52  *                                    client cmd try to talk to consumer
  53  *                                    ...
  54  *
  55  * However, since the consumer is a different daemon, we have no way of making
  56  * sure the command will reach it safely even with this state flag. This is why
  57  * we consider that up to the state validation during command processing, the
  58  * command is safe. After that, we can not guarantee the correctness of the
  59  * client request vis-a-vis the consumer.
  60  */
  61 extern enum consumerd_state the_ust_consumerd_state;
  62 extern enum consumerd_state the_kernel_consumerd_state;
  63
  64 /* Set in main.c at boot time of the daemon */
  65 extern struct lttng_kernel_abi_tracer_version the_kernel_tracer_version;
  66 extern struct lttng_kernel_abi_tracer_abi_version the_kernel_tracer_abi_version;
  67
  68 /* Notification thread handle. */
  69 extern struct notification_thread_handle *the_notification_thread_handle;
  70
  71 /* Rotation thread handle. */
  72 extern lttng::sessiond::rotation_thread::uptr the_rotation_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         /* Input message */
  81         struct lttcomm_session_msg lsm;
  82         /* Reply content, starts with an lttcomm_lttng_msg header. */
  83         struct lttng_payload reply_payload;
  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 extern int the_kernel_poll_pipe[2];
 122
 123 /*
 124  * Populated when the daemon starts with the current page size of the system.
 125  * Set in main() with the current page size.
 126  */
 127 extern long the_page_size;
 128
 129 /* Application health monitoring */
 130 extern struct health_app *the_health_sessiond;
 131
 132 extern struct sessiond_config the_config;
 133
 134 extern int the_ust_consumerd64_fd, the_ust_consumerd32_fd;
 135
 136 /* Parent PID for --sig-parent option */
 137 extern pid_t the_ppid;
 138 /* Internal parent PID use with daemonize. */
 139 extern pid_t the_child_ppid;
 140
 141 /* Consumer daemon specific control data. */
 142 extern struct consumer_data the_ustconsumer32_data;
 143 extern struct consumer_data the_ustconsumer64_data;
 144 extern struct consumer_data the_kconsumer_data;
 145
 146 int sessiond_init_main_quit_pipe();
 147 int sessiond_wait_for_main_quit_pipe(int timeout_ms);
 148 int sessiond_notify_main_quit_pipe();
 149 void sessiond_close_main_quit_pipe();
 150
 151 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 152 void sessiond_signal_parents();
 153
 154 void sessiond_set_client_thread_state(bool running);
 155 void sessiond_wait_client_thread_stopped();
 156
 157 void *thread_manage_consumer(void *data);
 158
 159 #endif /* _LTT_SESSIOND_H */