| 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 | |
| 28 | #include "snapshot.h" |
| 29 | #include "trace-kernel.h" |
| 30 | |
| 31 | struct ltt_ust_session; |
| 32 | |
| 33 | /* |
| 34 | * Tracing session list |
| 35 | * |
| 36 | * Statically declared in session.c and can be accessed by using |
| 37 | * session_get_list() function that returns the pointer to the list. |
| 38 | */ |
| 39 | struct ltt_session_list { |
| 40 | /* |
| 41 | * This lock protects any read/write access to the list and |
| 42 | * next_uuid. All public functions in session.c acquire this |
| 43 | * lock and release it before returning. If none of those |
| 44 | * functions are used, the lock MUST be acquired in order to |
| 45 | * iterate or/and do any actions on that list. |
| 46 | */ |
| 47 | pthread_mutex_t lock; |
| 48 | |
| 49 | /* |
| 50 | * Session unique ID generator. The session list lock MUST be |
| 51 | * upon update and read of this counter. |
| 52 | */ |
| 53 | uint64_t next_uuid; |
| 54 | |
| 55 | /* Linked list head */ |
| 56 | struct cds_list_head head; |
| 57 | }; |
| 58 | |
| 59 | /* |
| 60 | * This data structure contains information needed to identify a tracing |
| 61 | * session for both LTTng and UST. |
| 62 | */ |
| 63 | struct ltt_session { |
| 64 | char name[NAME_MAX]; |
| 65 | char hostname[HOST_NAME_MAX]; /* Local hostname. */ |
| 66 | struct ltt_kernel_session *kernel_session; |
| 67 | struct ltt_ust_session *ust_session; |
| 68 | /* |
| 69 | * Protect any read/write on this session data structure. This lock must be |
| 70 | * acquired *before* using any public functions declared below. Use |
| 71 | * session_lock() and session_unlock() for that. |
| 72 | */ |
| 73 | pthread_mutex_t lock; |
| 74 | struct cds_list_head list; |
| 75 | uint64_t id; /* session unique identifier */ |
| 76 | /* UID/GID of the user owning the session */ |
| 77 | uid_t uid; |
| 78 | gid_t gid; |
| 79 | /* |
| 80 | * Network session handle. A value of 0 means that there is no remote |
| 81 | * session established. |
| 82 | */ |
| 83 | uint64_t net_handle; |
| 84 | /* |
| 85 | * This consumer is only set when the create_session_uri call is made. |
| 86 | * This contains the temporary information for a consumer output. Upon |
| 87 | * creation of the UST or kernel session, this consumer, if available, is |
| 88 | * copied into those sessions. |
| 89 | */ |
| 90 | struct consumer_output *consumer; |
| 91 | |
| 92 | /* Did at least ONE start command has been triggered?. */ |
| 93 | unsigned int has_been_started:1; |
| 94 | /* |
| 95 | * Is the session active? Start trace command sets this to 1 and the stop |
| 96 | * command reset it to 0. |
| 97 | */ |
| 98 | unsigned int active:1; |
| 99 | |
| 100 | /* Snapshot representation in a session. */ |
| 101 | struct snapshot snapshot; |
| 102 | /* Indicate if the session has to output the traces or not. */ |
| 103 | unsigned int output_traces; |
| 104 | /* |
| 105 | * This session is in snapshot mode. This means that every channel enabled |
| 106 | * will be set in overwrite mode and mmap. It is considered exclusively for |
| 107 | * snapshot purposes. |
| 108 | */ |
| 109 | unsigned int snapshot_mode; |
| 110 | /* |
| 111 | * Timer set when the session is created for live reading. |
| 112 | */ |
| 113 | unsigned int live_timer; |
| 114 | /* |
| 115 | * Path where to keep the shared memory files. |
| 116 | */ |
| 117 | char shm_path[PATH_MAX]; |
| 118 | /* |
| 119 | * Node in ltt_sessions_ht_by_id. |
| 120 | */ |
| 121 | struct lttng_ht_node_u64 node; |
| 122 | /* Number of session rotation for this session. */ |
| 123 | uint64_t rotate_count; |
| 124 | /* |
| 125 | * Rotation is pending between the time it starts until the consumer has |
| 126 | * finished extracting the data. If the session uses a relay, data related |
| 127 | * to a rotation can still be in flight after that, see |
| 128 | * rotate_pending_relay. |
| 129 | */ |
| 130 | bool rotate_pending; |
| 131 | /* |
| 132 | * True until the relay has finished the rotation of all the streams. |
| 133 | */ |
| 134 | bool rotate_pending_relay; |
| 135 | /* Current state of a rotation. */ |
| 136 | enum lttng_rotation_state rotation_state; |
| 137 | /* |
| 138 | * Number of channels waiting for a rotation. |
| 139 | * When this number reaches 0, we can handle the rename of the chunk |
| 140 | * folder and inform the client that the rotate is finished. |
| 141 | */ |
| 142 | unsigned int nr_chan_rotate_pending; |
| 143 | struct { |
| 144 | /* |
| 145 | * When the rotation is in progress, the temporary path name is |
| 146 | * stored here. When the rotation is complete, the final path name |
| 147 | * is here and can be queried with the rotate_pending call. |
| 148 | */ |
| 149 | char current_rotate_path[LTTNG_PATH_MAX]; |
| 150 | /* |
| 151 | * The path where the consumer is currently writing after the first |
| 152 | * session rotation. |
| 153 | */ |
| 154 | char active_tracing_path[LTTNG_PATH_MAX]; |
| 155 | } rotation_chunk; |
| 156 | /* |
| 157 | * The timestamp of the beginning of the previous chunk. For the |
| 158 | * first chunk, this is the "lttng start" timestamp. For the |
| 159 | * subsequent ones, this copies the current_chunk_start_ts value when |
| 160 | * a new rotation starts. This value is used to set the name of a |
| 161 | * complete chunk directory, ex: "last_chunk_start_ts-now()". |
| 162 | */ |
| 163 | time_t last_chunk_start_ts; |
| 164 | /* |
| 165 | * This is the timestamp when a new chunk starts. When a new rotation |
| 166 | * starts, we copy this value to last_chunk_start_ts and replace it |
| 167 | * with the current timestamp. |
| 168 | */ |
| 169 | time_t current_chunk_start_ts; |
| 170 | /* |
| 171 | * Timer to check periodically if a relay has completed the last |
| 172 | * rotation. |
| 173 | */ |
| 174 | bool rotate_relay_pending_timer_enabled; |
| 175 | timer_t rotate_relay_pending_timer; |
| 176 | /* Timer to periodically rotate a session. */ |
| 177 | bool rotate_timer_enabled; |
| 178 | timer_t rotate_timer; |
| 179 | uint64_t rotate_timer_period; |
| 180 | /* Value for size-based rotation, 0 if disabled. */ |
| 181 | uint64_t rotate_size; |
| 182 | /* |
| 183 | * Keep a state if this session was rotated after the last stop command. |
| 184 | * We only allow one rotation after a stop. At destroy, we also need to |
| 185 | * know if a rotation occured since the last stop to rename the current |
| 186 | * chunk. |
| 187 | */ |
| 188 | bool rotated_after_last_stop; |
| 189 | /* |
| 190 | * Condition and trigger for size-based rotations. |
| 191 | */ |
| 192 | struct lttng_condition *rotate_condition; |
| 193 | struct lttng_trigger *rotate_trigger; |
| 194 | }; |
| 195 | |
| 196 | /* Prototypes */ |
| 197 | int session_create(char *name, uid_t uid, gid_t gid); |
| 198 | int session_destroy(struct ltt_session *session); |
| 199 | |
| 200 | void session_lock(struct ltt_session *session); |
| 201 | void session_lock_list(void); |
| 202 | void session_unlock(struct ltt_session *session); |
| 203 | void session_unlock_list(void); |
| 204 | |
| 205 | struct ltt_session *session_find_by_name(const char *name); |
| 206 | struct ltt_session *session_find_by_id(uint64_t id); |
| 207 | struct ltt_session_list *session_get_list(void); |
| 208 | |
| 209 | int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid); |
| 210 | |
| 211 | #endif /* _LTT_SESSION_H */ |