2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
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.
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.
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.
18 #ifndef _LTT_SESSION_H
19 #define _LTT_SESSION_H
22 #include <urcu/list.h>
24 #include <common/hashtable/hashtable.h>
25 #include <lttng/rotation.h>
28 #include "trace-kernel.h"
30 struct ltt_ust_session
;
33 * Tracing session list
35 * Statically declared in session.c and can be accessed by using
36 * session_get_list() function that returns the pointer to the list.
38 struct ltt_session_list
{
40 * This lock protects any read/write access to the list and
41 * next_uuid. All public functions in session.c acquire this
42 * lock and release it before returning. If none of those
43 * functions are used, the lock MUST be acquired in order to
44 * iterate or/and do any actions on that list.
49 * Session unique ID generator. The session list lock MUST be
50 * upon update and read of this counter.
54 /* Linked list head */
55 struct cds_list_head head
;
59 * This data structure contains information needed to identify a tracing
60 * session for both LTTng and UST.
64 char hostname
[HOST_NAME_MAX
]; /* Local hostname. */
65 struct ltt_kernel_session
*kernel_session
;
66 struct ltt_ust_session
*ust_session
;
68 * Protect any read/write on this session data structure. This lock must be
69 * acquired *before* using any public functions declared below. Use
70 * session_lock() and session_unlock() for that.
73 struct cds_list_head list
;
74 uint64_t id
; /* session unique identifier */
75 /* UID/GID of the user owning the session */
79 * Network session handle. A value of 0 means that there is no remote
80 * session established.
84 * This consumer is only set when the create_session_uri call is made.
85 * This contains the temporary information for a consumer output. Upon
86 * creation of the UST or kernel session, this consumer, if available, is
87 * copied into those sessions.
89 struct consumer_output
*consumer
;
91 /* Did at least ONE start command has been triggered?. */
92 unsigned int has_been_started
:1;
94 * Is the session active? Start trace command sets this to 1 and the stop
95 * command reset it to 0.
97 unsigned int active
:1;
99 /* Snapshot representation in a session. */
100 struct snapshot snapshot
;
101 /* Indicate if the session has to output the traces or not. */
102 unsigned int output_traces
;
104 * This session is in snapshot mode. This means that every channel enabled
105 * will be set in overwrite mode and mmap. It is considered exclusively for
108 unsigned int snapshot_mode
;
110 * Timer set when the session is created for live reading.
112 unsigned int live_timer
;
114 * Path where to keep the shared memory files.
116 char shm_path
[PATH_MAX
];
118 * Node in ltt_sessions_ht_by_id.
120 struct lttng_ht_node_u64 node
;
121 /* Number of session rotation for this session. */
122 uint64_t rotate_count
;
124 * Rotation is pending between the time it starts until the consumer has
125 * finished extracting the data. If the session uses a relay, data related
126 * to a rotation can still be in flight after that, see
127 * rotate_pending_relay.
130 /* Current status of a rotation. */
131 enum lttng_rotation_status rotation_status
;
133 * Number of channels waiting for a rotation.
134 * When this number reaches 0, we can handle the rename of the chunk
135 * folder and inform the client that the rotate is finished.
137 unsigned int nr_chan_rotate_pending
;
140 * When the rotation is in progress, the temporary path name is
141 * stored here. When the rotation is complete, the final path name
142 * is here and can be queried with the rotate_pending call.
144 char current_rotate_path
[LTTNG_PATH_MAX
];
146 * The path where the consumer is currently writing after the first
149 char active_tracing_path
[LTTNG_PATH_MAX
];
152 * The timestamp of the beginning of the previous chunk. For the
153 * first chunk, this is the "lttng start" timestamp. For the
154 * subsequent ones, this copies the current_chunk_start_ts value when
155 * a new rotation starts. This value is used to set the name of a
156 * complete chunk directory, ex: "last_chunk_start_ts-now()".
158 time_t last_chunk_start_ts
;
160 * This is the timestamp when a new chunk starts. When a new rotation
161 * starts, we copy this value to last_chunk_start_ts and replace it
162 * with the current timestamp.
164 time_t current_chunk_start_ts
;
168 int session_create(char *name
, uid_t uid
, gid_t gid
);
169 int session_destroy(struct ltt_session
*session
);
171 void session_lock(struct ltt_session
*session
);
172 void session_lock_list(void);
173 void session_unlock(struct ltt_session
*session
);
174 void session_unlock_list(void);
176 struct ltt_session
*session_find_by_name(const char *name
);
177 struct ltt_session
*session_find_by_id(uint64_t id
);
178 struct ltt_session_list
*session_get_list(void);
180 int session_access_ok(struct ltt_session
*session
, uid_t uid
, gid_t gid
);
182 #endif /* _LTT_SESSION_H */