| 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 <lttng/rotation.h> |
| 27 | #include <lttng/location.h> |
| 28 | |
| 29 | #include "snapshot.h" |
| 30 | #include "trace-kernel.h" |
| 31 | #include "consumer.h" |
| 32 | |
| 33 | struct ltt_ust_session; |
| 34 | |
| 35 | /* |
| 36 | * Tracing session list |
| 37 | * |
| 38 | * Statically declared in session.c and can be accessed by using |
| 39 | * session_get_list() function that returns the pointer to the list. |
| 40 | */ |
| 41 | struct ltt_session_list { |
| 42 | /* |
| 43 | * This lock protects any read/write access to the list and |
| 44 | * next_uuid. All public functions in session.c acquire this |
| 45 | * lock and release it before returning. If none of those |
| 46 | * functions are used, the lock MUST be acquired in order to |
| 47 | * iterate or/and do any actions on that list. |
| 48 | */ |
| 49 | pthread_mutex_t lock; |
| 50 | /* |
| 51 | * This condition variable is signaled on every removal from |
| 52 | * the session list. |
| 53 | */ |
| 54 | pthread_cond_t removal_cond; |
| 55 | |
| 56 | /* |
| 57 | * Session unique ID generator. The session list lock MUST be |
| 58 | * upon update and read of this counter. |
| 59 | */ |
| 60 | uint64_t next_uuid; |
| 61 | |
| 62 | /* Linked list head */ |
| 63 | struct cds_list_head head; |
| 64 | }; |
| 65 | |
| 66 | /* |
| 67 | * This data structure contains information needed to identify a tracing |
| 68 | * session for both LTTng and UST. |
| 69 | */ |
| 70 | struct ltt_session { |
| 71 | char name[NAME_MAX]; |
| 72 | char hostname[HOST_NAME_MAX]; /* Local hostname. */ |
| 73 | struct ltt_kernel_session *kernel_session; |
| 74 | struct ltt_ust_session *ust_session; |
| 75 | struct urcu_ref ref; |
| 76 | /* |
| 77 | * Protect any read/write on this session data structure. This lock must be |
| 78 | * acquired *before* using any public functions declared below. Use |
| 79 | * session_lock() and session_unlock() for that. |
| 80 | */ |
| 81 | pthread_mutex_t lock; |
| 82 | struct cds_list_head list; |
| 83 | uint64_t id; /* session unique identifier */ |
| 84 | /* Indicates if a destroy command has been applied to this session. */ |
| 85 | bool destroyed; |
| 86 | /* UID/GID of the user owning the session */ |
| 87 | uid_t uid; |
| 88 | gid_t gid; |
| 89 | /* |
| 90 | * Network session handle. A value of 0 means that there is no remote |
| 91 | * session established. |
| 92 | */ |
| 93 | uint64_t net_handle; |
| 94 | /* |
| 95 | * This consumer is only set when the create_session_uri call is made. |
| 96 | * This contains the temporary information for a consumer output. Upon |
| 97 | * creation of the UST or kernel session, this consumer, if available, is |
| 98 | * copied into those sessions. |
| 99 | */ |
| 100 | struct consumer_output *consumer; |
| 101 | |
| 102 | /* Did at least ONE start command has been triggered?. */ |
| 103 | unsigned int has_been_started:1; |
| 104 | /* |
| 105 | * Is the session active? Start trace command sets this to 1 and the stop |
| 106 | * command reset it to 0. |
| 107 | */ |
| 108 | unsigned int active:1; |
| 109 | |
| 110 | /* Snapshot representation in a session. */ |
| 111 | struct snapshot snapshot; |
| 112 | /* Indicate if the session has to output the traces or not. */ |
| 113 | unsigned int output_traces; |
| 114 | /* |
| 115 | * This session is in snapshot mode. This means that every channel enabled |
| 116 | * will be set in overwrite mode and mmap. It is considered exclusively for |
| 117 | * snapshot purposes. |
| 118 | */ |
| 119 | unsigned int snapshot_mode; |
| 120 | /* |
| 121 | * Timer set when the session is created for live reading. |
| 122 | */ |
| 123 | unsigned int live_timer; |
| 124 | /* |
| 125 | * Path where to keep the shared memory files. |
| 126 | */ |
| 127 | char shm_path[PATH_MAX]; |
| 128 | /* |
| 129 | * Node in ltt_sessions_ht_by_id. |
| 130 | */ |
| 131 | struct lttng_ht_node_u64 node; |
| 132 | /* |
| 133 | * The current archive id corresponds to the number of session rotations |
| 134 | * that have occurred for this session. The archive id |
| 135 | * is used to tag the "generation" of a stream. This tag allows the |
| 136 | * consumer and relay daemons to track when a given stream was created |
| 137 | * during the lifetime of a session. |
| 138 | * |
| 139 | * For instance, if a stream is created after a session rotation was |
| 140 | * launched, the consumer and relay daemons must not check its position |
| 141 | * to determine if that specific session rotation was completed. It is |
| 142 | * implicitly "completed" since the stream appeared _after_ the session |
| 143 | * rotation was initiated. |
| 144 | */ |
| 145 | uint64_t current_archive_id; |
| 146 | /* |
| 147 | * Rotation is considered pending between the time it is launched up |
| 148 | * until the moment when the data has been writen at the destination |
| 149 | * and the trace archive has been renamed. |
| 150 | * |
| 151 | * When tracing locally, only 'rotation_pending_local' is used since |
| 152 | * no remote checks are needed. However, when tracing to a relay daemon, |
| 153 | * a second check is needed to ensure that the data has been |
| 154 | * commited at the remote destination. |
| 155 | */ |
| 156 | bool rotation_pending_local; |
| 157 | bool rotation_pending_relay; |
| 158 | /* Current state of a rotation. */ |
| 159 | enum lttng_rotation_state rotation_state; |
| 160 | struct { |
| 161 | /* |
| 162 | * When the rotation is in progress, the temporary path name is |
| 163 | * stored here. When the rotation is complete, the final path name |
| 164 | * is here and can be queried with the rotate_pending call. |
| 165 | */ |
| 166 | char current_rotate_path[LTTNG_PATH_MAX]; |
| 167 | /* |
| 168 | * The path where the consumer is currently writing after the first |
| 169 | * session rotation. |
| 170 | */ |
| 171 | char active_tracing_path[LTTNG_PATH_MAX]; |
| 172 | } rotation_chunk; |
| 173 | /* |
| 174 | * The timestamp of the beginning of the previous chunk. For the |
| 175 | * first chunk, this is the "lttng start" timestamp. For the |
| 176 | * subsequent ones, this copies the current_chunk_start_ts value when |
| 177 | * a new rotation starts. This value is used to set the name of a |
| 178 | * complete chunk directory, ex: "last_chunk_start_ts-now()". |
| 179 | */ |
| 180 | time_t last_chunk_start_ts; |
| 181 | /* |
| 182 | * This is the timestamp when a new chunk starts. When a new rotation |
| 183 | * starts, we copy this value to last_chunk_start_ts and replace it |
| 184 | * with the current timestamp. |
| 185 | */ |
| 186 | time_t current_chunk_start_ts; |
| 187 | /* |
| 188 | * Timer to check periodically if a relay and/or consumer has completed |
| 189 | * the last rotation. |
| 190 | */ |
| 191 | bool rotation_pending_check_timer_enabled; |
| 192 | timer_t rotation_pending_check_timer; |
| 193 | /* Timer to periodically rotate a session. */ |
| 194 | bool rotation_schedule_timer_enabled; |
| 195 | timer_t rotation_schedule_timer; |
| 196 | /* Value for periodic rotations, 0 if disabled. */ |
| 197 | uint64_t rotate_timer_period; |
| 198 | /* Value for size-based rotations, 0 if disabled. */ |
| 199 | uint64_t rotate_size; |
| 200 | /* |
| 201 | * Keep a state if this session was rotated after the last stop command. |
| 202 | * We only allow one rotation after a stop. At destroy, we also need to |
| 203 | * know if a rotation occurred since the last stop to rename the current |
| 204 | * chunk. |
| 205 | */ |
| 206 | bool rotated_after_last_stop; |
| 207 | /* |
| 208 | * Condition and trigger for size-based rotations. |
| 209 | */ |
| 210 | struct lttng_condition *rotate_condition; |
| 211 | struct lttng_trigger *rotate_trigger; |
| 212 | }; |
| 213 | |
| 214 | /* Prototypes */ |
| 215 | int session_create(char *name, uid_t uid, gid_t gid); |
| 216 | |
| 217 | void session_lock(struct ltt_session *session); |
| 218 | void session_lock_list(void); |
| 219 | int session_trylock_list(void); |
| 220 | void session_unlock(struct ltt_session *session); |
| 221 | void session_unlock_list(void); |
| 222 | |
| 223 | void session_destroy(struct ltt_session *session); |
| 224 | |
| 225 | bool session_get(struct ltt_session *session); |
| 226 | void session_put(struct ltt_session *session); |
| 227 | |
| 228 | enum consumer_dst_type session_get_consumer_destination_type( |
| 229 | const struct ltt_session *session); |
| 230 | const char *session_get_net_consumer_hostname( |
| 231 | const struct ltt_session *session); |
| 232 | void session_get_net_consumer_ports( |
| 233 | const struct ltt_session *session, |
| 234 | uint16_t *control_port, uint16_t *data_port); |
| 235 | struct lttng_trace_archive_location *session_get_trace_archive_location( |
| 236 | struct ltt_session *session); |
| 237 | |
| 238 | struct ltt_session *session_find_by_name(const char *name); |
| 239 | struct ltt_session *session_find_by_id(uint64_t id); |
| 240 | |
| 241 | struct ltt_session_list *session_get_list(void); |
| 242 | void session_list_wait_empty(void); |
| 243 | |
| 244 | int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid); |
| 245 | |
| 246 | int session_reset_rotation_state(struct ltt_session *session, |
| 247 | enum lttng_rotation_state result); |
| 248 | |
| 249 | #endif /* _LTT_SESSION_H */ |