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 struct lttng_kernel_tracer_version kernel_tracer_version;
  79 extern struct lttng_kernel_tracer_abi_version kernel_tracer_abi_version;
  80
  81 /* Notification thread handle. */
  82 extern struct notification_thread_handle *notification_thread_handle;
  83
  84 /*
  85  * This contains extra data needed for processing a command received by the
  86  * session daemon from the lttng client.
  87  */
  88 struct command_ctx {
  89         unsigned int lttng_msg_size;
  90         struct ltt_session *session;
  91         struct lttcomm_lttng_msg *llm;
  92         struct lttcomm_session_msg *lsm;
  93         lttng_sock_cred creds;
  94 };
  95
  96 struct ust_command {
  97         int sock;
  98         struct ust_register_msg reg_msg;
  99         struct cds_wfcq_node node;
 100 };
 101
 102 /*
 103  * Queue used to enqueue UST registration request (ust_command) and synchronized
 104  * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
 105  */
 106 struct ust_cmd_queue {
 107         int32_t futex;
 108         struct cds_wfcq_head head;
 109         struct cds_wfcq_tail tail;
 110 };
 111
 112 /*
 113  * This is the wait queue containing wait nodes during the application
 114  * registration process.
 115  */
 116 struct ust_reg_wait_queue {
 117         unsigned long count;
 118         struct cds_list_head head;
 119 };
 120
 121 /*
 122  * Use by the dispatch registration to queue UST command socket to wait for the
 123  * notify socket.
 124  */
 125 struct ust_reg_wait_node {
 126         struct ust_app *app;
 127         struct cds_list_head head;
 128 };
 129
 130 /*
 131  * Used to notify that a hash table needs to be destroyed by dedicated
 132  * thread. Required by design because we don't want to move destroy
 133  * paths outside of large RCU read-side lock paths, and destroy cannot
 134  * be called by call_rcu thread, because it may hang (waiting for
 135  * call_rcu completion).
 136  */
 137 extern int ht_cleanup_pipe[2];
 138
 139 extern int kernel_poll_pipe[2];
 140
 141 /*
 142  * Populated when the daemon starts with the current page size of the system.
 143  * Set in main() with the current page size.
 144  */
 145 extern long page_size;
 146
 147 /* Application health monitoring */
 148 extern struct health_app *health_sessiond;
 149
 150 extern struct sessiond_config config;
 151
 152 extern int ust_consumerd64_fd, ust_consumerd32_fd;
 153
 154 /* Parent PID for --sig-parent option */
 155 extern pid_t ppid;
 156 /* Internal parent PID use with daemonize. */
 157 extern pid_t child_ppid;
 158
 159 /* Consumer daemon specific control data. */
 160 extern struct consumer_data ustconsumer32_data;
 161 extern struct consumer_data ustconsumer64_data;
 162 extern struct consumer_data kconsumer_data;
 163
 164 int sessiond_init_thread_quit_pipe(void);
 165 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
 166 int sessiond_wait_for_quit_pipe(int timeout_ms);
 167 int sessiond_notify_quit_pipe(void);
 168 void sessiond_close_quit_pipe(void);
 169
 170 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 171 void sessiond_signal_parents(void);
 172
 173 void sessiond_set_client_thread_state(bool running);
 174 void sessiond_wait_client_thread_stopped(void);
 175
 176 void *thread_manage_consumer(void *data);
 177
 178 #endif /* _LTT_SESSIOND_H */