src/bin/lttng-sessiond/session.h

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef _LTT_SESSION_H
  19 #define _LTT_SESSION_H
  20
  21 #include <limits.h>
  22 #include <stdbool.h>
  23 #include <urcu/list.h>
  24
  25 #include <common/hashtable/hashtable.h>
  26 #include <common/dynamic-array.h>
  27 #include <lttng/rotation.h>
  28 #include <lttng/location.h>
  29 #include <lttng/lttng-error.h>
  30
  31 #include "snapshot.h"
  32 #include "trace-kernel.h"
  33 #include "consumer.h"
  34
  35 struct ltt_ust_session;
  36
  37 typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
  38                 void *user_data);
  39
  40 /*
  41  * Tracing session list
  42  *
  43  * Statically declared in session.c and can be accessed by using
  44  * session_get_list() function that returns the pointer to the list.
  45  */
  46 struct ltt_session_list {
  47         /*
  48          * This lock protects any read/write access to the list and
  49          * next_uuid. All public functions in session.c acquire this
  50          * lock and release it before returning. If none of those
  51          * functions are used, the lock MUST be acquired in order to
  52          * iterate or/and do any actions on that list.
  53          */
  54         pthread_mutex_t lock;
  55         /*
  56          * This condition variable is signaled on every removal from
  57          * the session list.
  58          */
  59         pthread_cond_t removal_cond;
  60
  61         /*
  62          * Session unique ID generator. The session list lock MUST be
  63          * upon update and read of this counter.
  64          */
  65         uint64_t next_uuid;
  66
  67         /* Linked list head */
  68         struct cds_list_head head;
  69 };
  70
  71 /*
  72  * This data structure contains information needed to identify a tracing
  73  * session for both LTTng and UST.
  74  */
  75 struct ltt_session {
  76         char name[NAME_MAX];
  77         bool has_auto_generated_name;
  78         char hostname[HOST_NAME_MAX]; /* Local hostname. */
  79         time_t creation_time;
  80         struct ltt_kernel_session *kernel_session;
  81         struct ltt_ust_session *ust_session;
  82         struct urcu_ref ref;
  83         /*
  84          * Protect any read/write on this session data structure. This lock must be
  85          * acquired *before* using any public functions declared below. Use
  86          * session_lock() and session_unlock() for that.
  87          */
  88         pthread_mutex_t lock;
  89         struct cds_list_head list;
  90         uint64_t id;            /* session unique identifier */
  91         /* Indicates if the session has been added to the session list and ht.*/
  92         bool published;
  93         /* Indicates if a destroy command has been applied to this session. */
  94         bool destroyed;
  95         /* UID/GID of the user owning the session */
  96         uid_t uid;
  97         gid_t gid;
  98         /*
  99          * Network session handle. A value of 0 means that there is no remote
 100          * session established.
 101          */
 102         uint64_t net_handle;
 103         /*
 104          * This consumer is only set when the create_session_uri call is made.
 105          * This contains the temporary information for a consumer output. Upon
 106          * creation of the UST or kernel session, this consumer, if available, is
 107          * copied into those sessions.
 108          */
 109         struct consumer_output *consumer;
 110         /*
 111          * Indicates whether or not the user has specified an output directory
 112          * or if it was configured using the default configuration.
 113          */
 114         bool has_user_specified_directory;
 115         /* Did at least ONE start command has been triggered?. */
 116         unsigned int has_been_started:1;
 117         /*
 118          * Is the session active? Start trace command sets this to 1 and the stop
 119          * command reset it to 0.
 120          */
 121         unsigned int active:1;
 122
 123         /* Snapshot representation in a session. */
 124         struct snapshot snapshot;
 125         /* Indicate if the session has to output the traces or not. */
 126         unsigned int output_traces;
 127         /*
 128          * This session is in snapshot mode. This means that channels enabled
 129          * will be set in overwrite mode by default and must be in mmap
 130          * output mode. Note that snapshots can be taken on a session that
 131          * is not in "snapshot_mode". This parameter only affects channel
 132          * creation defaults.
 133          */
 134         unsigned int snapshot_mode;
 135         /*
 136          * A session that has channels that don't use 'mmap' output can't be
 137          * used to capture snapshots. This is set to true whenever a
 138          * 'splice' kernel channel is enabled.
 139          */
 140         bool has_non_mmap_channel;
 141         /*
 142          * Timer set when the session is created for live reading.
 143          */
 144         unsigned int live_timer;
 145         /*
 146          * Path where to keep the shared memory files.
 147          */
 148         char shm_path[PATH_MAX];
 149         /*
 150          * Node in ltt_sessions_ht_by_id.
 151          */
 152         struct lttng_ht_node_u64 node;
 153         /*
 154          * Timer to check periodically if a relay and/or consumer has completed
 155          * the last rotation.
 156          */
 157         bool rotation_pending_check_timer_enabled;
 158         timer_t rotation_pending_check_timer;
 159         /* Timer to periodically rotate a session. */
 160         bool rotation_schedule_timer_enabled;
 161         timer_t rotation_schedule_timer;
 162         /* Value for periodic rotations, 0 if disabled. */
 163         uint64_t rotate_timer_period;
 164         /* Value for size-based rotations, 0 if disabled. */
 165         uint64_t rotate_size;
 166         /*
 167          * Keep a state if this session was rotated after the last stop command.
 168          * We only allow one rotation after a stop. At destroy, we also need to
 169          * know if a rotation occurred since the last stop to rename the current
 170          * chunk.
 171          */
 172         bool rotated_after_last_stop;
 173         /*
 174          * Condition and trigger for size-based rotations.
 175          */
 176         struct lttng_condition *rotate_condition;
 177         struct lttng_trigger *rotate_trigger;
 178         LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
 179         struct lttng_trace_chunk *current_trace_chunk;
 180         struct lttng_trace_chunk *chunk_being_archived;
 181         /* Current state of a rotation. */
 182         enum lttng_rotation_state rotation_state;
 183         char *last_archived_chunk_name;
 184         LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
 185         struct lttng_dynamic_array destroy_notifiers;
 186 };
 187
 188 /* Prototypes */
 189 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
 190                 struct ltt_session **out_session);
 191 void session_lock(struct ltt_session *session);
 192 void session_lock_list(void);
 193 int session_trylock_list(void);
 194 void session_unlock(struct ltt_session *session);
 195 void session_unlock_list(void);
 196
 197 void session_destroy(struct ltt_session *session);
 198 int session_add_destroy_notifier(struct ltt_session *session,
 199                 ltt_session_destroy_notifier notifier, void *user_data);
 200
 201 bool session_get(struct ltt_session *session);
 202 void session_put(struct ltt_session *session);
 203
 204 enum consumer_dst_type session_get_consumer_destination_type(
 205                 const struct ltt_session *session);
 206 const char *session_get_net_consumer_hostname(
 207                 const struct ltt_session *session);
 208 void session_get_net_consumer_ports(
 209                 const struct ltt_session *session,
 210                 uint16_t *control_port, uint16_t *data_port);
 211 struct lttng_trace_archive_location *session_get_trace_archive_location(
 212                 const struct ltt_session *session);
 213
 214 struct ltt_session *session_find_by_name(const char *name);
 215 struct ltt_session *session_find_by_id(uint64_t id);
 216
 217 struct ltt_session_list *session_get_list(void);
 218 void session_list_wait_empty(void);
 219
 220 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
 221
 222 int session_reset_rotation_state(struct ltt_session *session,
 223                 enum lttng_rotation_state result);
 224
 225 /* Create a new trace chunk object from the session's configuration. */
 226 struct lttng_trace_chunk *session_create_new_trace_chunk(
 227                 struct ltt_session *session,
 228                 const char *session_base_path_override,
 229                 const char *chunk_name_override);
 230
 231 /*
 232  * Set `new_trace_chunk` as the session's current trace chunk. A reference
 233  * to `new_trace_chunk` is acquired by the session. The chunk is created
 234  * on remote peers (consumer and relay daemons).
 235  *
 236  * A reference to the session's current trace chunk is returned through
 237  * `current_session_trace_chunk` on success.
 238  */
 239 int session_set_trace_chunk(struct ltt_session *session,
 240                 struct lttng_trace_chunk *new_trace_chunk,
 241                 struct lttng_trace_chunk **current_session_trace_chunk);
 242
 243 /*
 244  * Close a chunk on the remote peers of a session. Has no effect on the
 245  * ltt_session itself.
 246  */
 247 int session_close_trace_chunk(const struct ltt_session *session,
 248                 struct lttng_trace_chunk *trace_chunk,
 249                 const enum lttng_trace_chunk_command_type *close_command);
 250
 251 #endif /* _LTT_SESSION_H */