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  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #ifndef _LTT_SESSIOND_H
  20 #define _LTT_SESSIOND_H
  21
  22 #include <urcu.h>
  23 #include <urcu/wfcqueue.h>
  24
  25 #include <common/sessiond-comm/sessiond-comm.h>
  26 #include <common/compat/poll.h>
  27 #include <common/compat/socket.h>
  28 #include <common/compat/uuid.h>
  29
  30 #include "session.h"
  31 #include "ust-app.h"
  32 #include "notification-thread.h"
  33 #include "sessiond-config.h"
  34
  35 /*
  36  * Consumer daemon state which is changed when spawning it, killing it or in
  37  * case of a fatal error.
  38  */
  39 enum consumerd_state {
  40         CONSUMER_STARTED = 1,
  41         CONSUMER_STOPPED = 2,
  42         CONSUMER_ERROR   = 3,
  43 };
  44
  45 /* Unique identifier of a session daemon instance. */
  46 extern lttng_uuid sessiond_uuid;
  47
  48 /*
  49  * This consumer daemon state is used to validate if a client command will be
  50  * able to reach the consumer. If not, the client is informed. For instance,
  51  * doing a "lttng start" when the consumer state is set to ERROR will return an
  52  * error to the client.
  53  *
  54  * The following example shows a possible race condition of this scheme:
  55  *
  56  * consumer thread error happens
  57  *                                    client cmd arrives
  58  *                                    client cmd checks state -> still OK
  59  * consumer thread exit, sets error
  60  *                                    client cmd try to talk to consumer
  61  *                                    ...
  62  *
  63  * However, since the consumer is a different daemon, we have no way of making
  64  * sure the command will reach it safely even with this state flag. This is why
  65  * we consider that up to the state validation during command processing, the
  66  * command is safe. After that, we can not guarantee the correctness of the
  67  * client request vis-a-vis the consumer.
  68  */
  69 extern enum consumerd_state ust_consumerd_state;
  70 extern enum consumerd_state kernel_consumerd_state;
  71
  72 extern const char default_home_dir[],
  73         default_tracing_group[],
  74         default_ust_sock_dir[],
  75         default_global_apps_pipe[];
  76
  77 /* Set in main.c at boot time of the daemon */
  78 extern int kernel_tracer_fd;
  79 extern struct lttng_kernel_tracer_version kernel_tracer_version;
  80 extern struct lttng_kernel_tracer_abi_version kernel_tracer_abi_version;
  81
  82 /* Notification thread handle. */
  83 extern struct notification_thread_handle *notification_thread_handle;
  84
  85 /*
  86  * This contains extra data needed for processing a command received by the
  87  * session daemon from the lttng client.
  88  */
  89 struct command_ctx {
  90         unsigned int lttng_msg_size;
  91         struct ltt_session *session;
  92         struct lttcomm_lttng_msg *llm;
  93         struct lttcomm_session_msg *lsm;
  94         lttng_sock_cred creds;
  95 };
  96
  97 struct ust_command {
  98         int sock;
  99         struct ust_register_msg reg_msg;
 100         struct cds_wfcq_node node;
 101 };
 102
 103 /*
 104  * Queue used to enqueue UST registration request (ust_command) and synchronized
 105  * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
 106  */
 107 struct ust_cmd_queue {
 108         int32_t futex;
 109         struct cds_wfcq_head head;
 110         struct cds_wfcq_tail tail;
 111 };
 112
 113 /*
 114  * This is the wait queue containing wait nodes during the application
 115  * registration process.
 116  */
 117 struct ust_reg_wait_queue {
 118         unsigned long count;
 119         struct cds_list_head head;
 120 };
 121
 122 /*
 123  * Use by the dispatch registration to queue UST command socket to wait for the
 124  * notify socket.
 125  */
 126 struct ust_reg_wait_node {
 127         struct ust_app *app;
 128         struct cds_list_head head;
 129 };
 130
 131 /*
 132  * Used to notify that a hash table needs to be destroyed by dedicated
 133  * thread. Required by design because we don't want to move destroy
 134  * paths outside of large RCU read-side lock paths, and destroy cannot
 135  * be called by call_rcu thread, because it may hang (waiting for
 136  * call_rcu completion).
 137  */
 138 extern int ht_cleanup_pipe[2];
 139
 140 extern int kernel_poll_pipe[2];
 141
 142 /*
 143  * Populated when the daemon starts with the current page size of the system.
 144  * Set in main() with the current page size.
 145  */
 146 extern long page_size;
 147
 148 /* Application health monitoring */
 149 extern struct health_app *health_sessiond;
 150
 151 extern struct sessiond_config config;
 152
 153 extern int ust_consumerd64_fd, ust_consumerd32_fd;
 154
 155 /* Parent PID for --sig-parent option */
 156 extern pid_t ppid;
 157 /* Internal parent PID use with daemonize. */
 158 extern pid_t child_ppid;
 159
 160 /* Consumer daemon specific control data. */
 161 extern struct consumer_data ustconsumer32_data;
 162 extern struct consumer_data ustconsumer64_data;
 163 extern struct consumer_data kconsumer_data;
 164
 165 int sessiond_init_thread_quit_pipe(void);
 166 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
 167 int sessiond_wait_for_quit_pipe(unsigned int timeout_us);
 168 int sessiond_notify_quit_pipe(void);
 169 void sessiond_close_quit_pipe(void);
 170
 171 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 172 void sessiond_signal_parents(void);
 173
 174 void sessiond_set_client_thread_state(bool running);
 175 void sessiond_wait_client_thread_stopped(void);
 176
 177 void *thread_manage_consumer(void *data);
 178
 179 #endif /* _LTT_SESSIOND_H */