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
  29 #include "session.h"
  30 #include "ust-app.h"
  31 #include "notification-thread.h"
  32 #include "sessiond-config.h"
  33
  34 /*
  35  * Consumer daemon state which is changed when spawning it, killing it or in
  36  * case of a fatal error.
  37  */
  38 enum consumerd_state {
  39         CONSUMER_STARTED = 1,
  40         CONSUMER_STOPPED = 2,
  41         CONSUMER_ERROR   = 3,
  42 };
  43
  44 /*
  45  * This consumer daemon state is used to validate if a client command will be
  46  * able to reach the consumer. If not, the client is informed. For instance,
  47  * doing a "lttng start" when the consumer state is set to ERROR will return an
  48  * error to the client.
  49  *
  50  * The following example shows a possible race condition of this scheme:
  51  *
  52  * consumer thread error happens
  53  *                                    client cmd arrives
  54  *                                    client cmd checks state -> still OK
  55  * consumer thread exit, sets error
  56  *                                    client cmd try to talk to consumer
  57  *                                    ...
  58  *
  59  * However, since the consumer is a different daemon, we have no way of making
  60  * sure the command will reach it safely even with this state flag. This is why
  61  * we consider that up to the state validation during command processing, the
  62  * command is safe. After that, we can not guarantee the correctness of the
  63  * client request vis-a-vis the consumer.
  64  */
  65 extern enum consumerd_state ust_consumerd_state;
  66 extern enum consumerd_state kernel_consumerd_state;
  67
  68 extern const char default_home_dir[],
  69         default_tracing_group[],
  70         default_ust_sock_dir[],
  71         default_global_apps_pipe[];
  72
  73 /* Set in main.c at boot time of the daemon */
  74 extern int kernel_tracer_fd;
  75 extern struct lttng_kernel_tracer_version kernel_tracer_version;
  76 extern struct lttng_kernel_tracer_abi_version kernel_tracer_abi_version;
  77
  78 /* Notification thread handle. */
  79 extern struct notification_thread_handle *notification_thread_handle;
  80
  81 /*
  82  * This contains extra data needed for processing a command received by the
  83  * session daemon from the lttng client.
  84  */
  85 struct command_ctx {
  86         int ust_sock;
  87         unsigned int lttng_msg_size;
  88         struct ltt_session *session;
  89         struct lttcomm_lttng_msg *llm;
  90         struct lttcomm_session_msg *lsm;
  91         lttng_sock_cred creds;
  92 };
  93
  94 struct ust_command {
  95         int sock;
  96         struct ust_register_msg reg_msg;
  97         struct cds_wfcq_node node;
  98 };
  99
 100 /*
 101  * Queue used to enqueue UST registration request (ust_command) and synchronized
 102  * by a futex with a scheme N wakers / 1 waiters. See futex.c/.h
 103  */
 104 struct ust_cmd_queue {
 105         int32_t futex;
 106         struct cds_wfcq_head head;
 107         struct cds_wfcq_tail tail;
 108 };
 109
 110 /*
 111  * This is the wait queue containing wait nodes during the application
 112  * registration process.
 113  */
 114 struct ust_reg_wait_queue {
 115         unsigned long count;
 116         struct cds_list_head head;
 117 };
 118
 119 /*
 120  * Use by the dispatch registration to queue UST command socket to wait for the
 121  * notify socket.
 122  */
 123 struct ust_reg_wait_node {
 124         struct ust_app *app;
 125         struct cds_list_head head;
 126 };
 127
 128 /*
 129  * Used to notify that a hash table needs to be destroyed by dedicated
 130  * thread. Required by design because we don't want to move destroy
 131  * paths outside of large RCU read-side lock paths, and destroy cannot
 132  * be called by call_rcu thread, because it may hang (waiting for
 133  * call_rcu completion).
 134  */
 135 extern int ht_cleanup_pipe[2];
 136
 137 extern int kernel_poll_pipe[2];
 138
 139 /*
 140  * Populated when the daemon starts with the current page size of the system.
 141  * Set in main() with the current page size.
 142  */
 143 extern long page_size;
 144
 145 /* Application health monitoring */
 146 extern struct health_app *health_sessiond;
 147
 148 extern struct sessiond_config config;
 149
 150 extern int ust_consumerd64_fd, ust_consumerd32_fd;
 151
 152 /* Parent PID for --sig-parent option */
 153 extern pid_t ppid;
 154 /* Internal parent PID use with daemonize. */
 155 extern pid_t child_ppid;
 156
 157 /* Consumer daemon specific control data. */
 158 extern struct consumer_data ustconsumer32_data;
 159 extern struct consumer_data ustconsumer64_data;
 160 extern struct consumer_data kconsumer_data;
 161
 162 int sessiond_init_thread_quit_pipe(void);
 163 int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
 164 int sessiond_wait_for_quit_pipe(unsigned int timeout_us);
 165 int sessiond_notify_quit_pipe(void);
 166 void sessiond_close_quit_pipe(void);
 167
 168 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 169 void sessiond_signal_parents(void);
 170
 171 void sessiond_set_client_thread_state(bool running);
 172 void sessiond_wait_client_thread_stopped(void);
 173
 174 void *thread_manage_consumer(void *data);
 175
 176 #endif /* _LTT_SESSIOND_H */