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 typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
  40                 void *user_data);
  41
  42 /*
  43  * Tracing session list
  44  *
  45  * Statically declared in session.c and can be accessed by using
  46  * session_get_list() function that returns the pointer to the list.
  47  */
  48 struct ltt_session_list {
  49         /*
  50          * This lock protects any read/write access to the list and
  51          * next_uuid. All public functions in session.c acquire this
  52          * lock and release it before returning. If none of those
  53          * functions are used, the lock MUST be acquired in order to
  54          * iterate or/and do any actions on that list.
  55          */
  56         pthread_mutex_t lock;
  57         /*
  58          * This condition variable is signaled on every removal from
  59          * the session list.
  60          */
  61         pthread_cond_t removal_cond;
  62
  63         /*
  64          * Session unique ID generator. The session list lock MUST be
  65          * upon update and read of this counter.
  66          */
  67         uint64_t next_uuid;
  68
  69         /* Linked list head */
  70         struct cds_list_head head;
  71 };
  72
  73 /*
  74  * This data structure contains information needed to identify a tracing
  75  * session for both LTTng and UST.
  76  */
  77 struct ltt_session {
  78         char name[NAME_MAX];
  79         bool has_auto_generated_name;
  80         bool name_contains_creation_time;
  81         char hostname[HOST_NAME_MAX]; /* Local hostname. */
  82         /* Path of the last closed chunk. */
  83         char last_chunk_path[LTTNG_PATH_MAX];
  84         time_t creation_time;
  85         struct ltt_kernel_session *kernel_session;
  86         struct ltt_ust_session *ust_session;
  87         struct urcu_ref ref;
  88         /*
  89          * Protect any read/write on this session data structure. This lock must be
  90          * acquired *before* using any public functions declared below. Use
  91          * session_lock() and session_unlock() for that.
  92          */
  93         pthread_mutex_t lock;
  94         struct cds_list_head list;
  95         uint64_t id;            /* session unique identifier */
  96         /* Indicates if the session has been added to the session list and ht.*/
  97         bool published;
  98         /* Indicates if a destroy command has been applied to this session. */
  99         bool destroyed;
 100         /* UID/GID of the user owning the session */
 101         uid_t uid;
 102         gid_t gid;
 103         /*
 104          * Network session handle. A value of 0 means that there is no remote
 105          * session established.
 106          */
 107         uint64_t net_handle;
 108         /*
 109          * This consumer is only set when the create_session_uri call is made.
 110          * This contains the temporary information for a consumer output. Upon
 111          * creation of the UST or kernel session, this consumer, if available, is
 112          * copied into those sessions.
 113          */
 114         struct consumer_output *consumer;
 115         /*
 116          * Indicates whether or not the user has specified an output directory
 117          * or if it was configured using the default configuration.
 118          */
 119         bool has_user_specified_directory;
 120         /* Did at least ONE start command has been triggered?. */
 121         unsigned int has_been_started:1;
 122         /*
 123          * Is the session active? Start trace command sets this to 1 and the stop
 124          * command reset it to 0.
 125          */
 126         unsigned int active:1;
 127
 128         /* Snapshot representation in a session. */
 129         struct snapshot snapshot;
 130         /* Indicate if the session has to output the traces or not. */
 131         unsigned int output_traces;
 132         /*
 133          * This session is in snapshot mode. This means that channels enabled
 134          * will be set in overwrite mode by default and must be in mmap
 135          * output mode. Note that snapshots can be taken on a session that
 136          * is not in "snapshot_mode". This parameter only affects channel
 137          * creation defaults.
 138          */
 139         unsigned int snapshot_mode;
 140         /*
 141          * A session that has channels that don't use 'mmap' output can't be
 142          * used to capture snapshots. This is set to true whenever a
 143          * 'splice' kernel channel is enabled.
 144          */
 145         bool has_non_mmap_channel;
 146         /*
 147          * Timer set when the session is created for live reading.
 148          */
 149         unsigned int live_timer;
 150         /*
 151          * Path where to keep the shared memory files.
 152          */
 153         char shm_path[PATH_MAX];
 154         /*
 155          * Node in ltt_sessions_ht_by_id.
 156          */
 157         struct lttng_ht_node_u64 node;
 158         /*
 159          * Timer to check periodically if a relay and/or consumer has completed
 160          * the last rotation.
 161          */
 162         bool rotation_pending_check_timer_enabled;
 163         timer_t rotation_pending_check_timer;
 164         /* Timer to periodically rotate a session. */
 165         bool rotation_schedule_timer_enabled;
 166         timer_t rotation_schedule_timer;
 167         /* Value for periodic rotations, 0 if disabled. */
 168         uint64_t rotate_timer_period;
 169         /* Value for size-based rotations, 0 if disabled. */
 170         uint64_t rotate_size;
 171         /*
 172          * Keep a state if this session was rotated after the last stop command.
 173          * We only allow one rotation after a stop. At destroy, we also need to
 174          * know if a rotation occurred since the last stop to rename the current
 175          * chunk.
 176          */
 177         bool rotated_after_last_stop;
 178         /*
 179          * Track whether the session was cleared after last stop. All subsequent
 180          * clear (without prior start) will succeed, but will be effect-less. A
 181          * subsequent rotate (without prior start) will return an error.
 182          */
 183         bool cleared_after_last_stop;
 184         /*
 185          * Condition and trigger for size-based rotations.
 186          */
 187         struct lttng_condition *rotate_condition;
 188         struct lttng_trigger *rotate_trigger;
 189         LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
 190         struct lttng_trace_chunk *current_trace_chunk;
 191         struct lttng_trace_chunk *chunk_being_archived;
 192         /* Current state of a rotation. */
 193         enum lttng_rotation_state rotation_state;
 194         bool quiet_rotation;
 195         char *last_archived_chunk_name;
 196         LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
 197         struct lttng_dynamic_array destroy_notifiers;
 198         struct lttng_dynamic_array clear_notifiers;
 199         /* Session base path override. Set non-null. */
 200         char *base_path;
 201 };
 202
 203 /* Prototypes */
 204 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
 205                 struct ltt_session **out_session);
 206 void session_lock(struct ltt_session *session);
 207 void session_lock_list(void);
 208 int session_trylock_list(void);
 209 void session_unlock(struct ltt_session *session);
 210 void session_unlock_list(void);
 211
 212 void session_destroy(struct ltt_session *session);
 213 int session_add_destroy_notifier(struct ltt_session *session,
 214                 ltt_session_destroy_notifier notifier, void *user_data);
 215
 216 int session_add_clear_notifier(struct ltt_session *session,
 217                 ltt_session_clear_notifier notifier, void *user_data);
 218 void session_notify_clear(struct ltt_session *session);
 219
 220 bool session_get(struct ltt_session *session);
 221 void session_put(struct ltt_session *session);
 222
 223 enum consumer_dst_type session_get_consumer_destination_type(
 224                 const struct ltt_session *session);
 225 const char *session_get_net_consumer_hostname(
 226                 const struct ltt_session *session);
 227 void session_get_net_consumer_ports(
 228                 const struct ltt_session *session,
 229                 uint16_t *control_port, uint16_t *data_port);
 230 struct lttng_trace_archive_location *session_get_trace_archive_location(
 231                 const struct ltt_session *session);
 232
 233 struct ltt_session *session_find_by_name(const char *name);
 234 struct ltt_session *session_find_by_id(uint64_t id);
 235
 236 struct ltt_session_list *session_get_list(void);
 237 void session_list_wait_empty(void);
 238
 239 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
 240
 241 int session_reset_rotation_state(struct ltt_session *session,
 242                 enum lttng_rotation_state result);
 243
 244 /* Create a new trace chunk object from the session's configuration. */
 245 struct lttng_trace_chunk *session_create_new_trace_chunk(
 246                 const struct ltt_session *session,
 247                 const struct consumer_output *consumer_output_override,
 248                 const char *session_base_path_override,
 249                 const char *chunk_name_override);
 250
 251 /*
 252  * Set `new_trace_chunk` as the session's current trace chunk. A reference
 253  * to `new_trace_chunk` is acquired by the session. The chunk is created
 254  * on remote peers (consumer and relay daemons).
 255  *
 256  * A reference to the session's current trace chunk is returned through
 257  * `current_session_trace_chunk` on success.
 258  */
 259 int session_set_trace_chunk(struct ltt_session *session,
 260                 struct lttng_trace_chunk *new_trace_chunk,
 261                 struct lttng_trace_chunk **current_session_trace_chunk);
 262
 263 /*
 264  * Close a chunk on the remote peers of a session. Has no effect on the
 265  * ltt_session itself.
 266  */
 267 int session_close_trace_chunk(struct ltt_session *session,
 268                 struct lttng_trace_chunk *trace_chunk,
 269                 enum lttng_trace_chunk_command_type close_command,
 270                 char *path);
 271
 272 bool session_output_supports_trace_chunks(const struct ltt_session *session);
 273
 274 #endif /* _LTT_SESSION_H */