Fix: mark ltt_sessions_ht_destroy as static
[lttng-tools.git] / 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 <urcu/list.h>
23
24 #include <common/hashtable/hashtable.h>
25
26 #include "snapshot.h"
27 #include "trace-kernel.h"
28
29 struct ltt_ust_session;
30
31 /*
32 * Tracing session list
33 *
34 * Statically declared in session.c and can be accessed by using
35 * session_get_list() function that returns the pointer to the list.
36 */
37 struct ltt_session_list {
38 /*
39 * This lock protects any read/write access to the list and
40 * next_uuid. All public functions in session.c acquire this
41 * lock and release it before returning. If none of those
42 * functions are used, the lock MUST be acquired in order to
43 * iterate or/and do any actions on that list.
44 */
45 pthread_mutex_t lock;
46
47 /*
48 * Session unique ID generator. The session list lock MUST be
49 * upon update and read of this counter.
50 */
51 uint64_t next_uuid;
52
53 /* Linked list head */
54 struct cds_list_head head;
55 };
56
57 /*
58 * This data structure contains information needed to identify a tracing
59 * session for both LTTng and UST.
60 */
61 struct ltt_session {
62 char name[NAME_MAX];
63 char hostname[HOST_NAME_MAX]; /* Local hostname. */
64 struct ltt_kernel_session *kernel_session;
65 struct ltt_ust_session *ust_session;
66 /*
67 * Protect any read/write on this session data structure. This lock must be
68 * acquired *before* using any public functions declared below. Use
69 * session_lock() and session_unlock() for that.
70 */
71 pthread_mutex_t lock;
72 struct cds_list_head list;
73 uint64_t id; /* session unique identifier */
74 /* UID/GID of the user owning the session */
75 uid_t uid;
76 gid_t gid;
77 /*
78 * Network session handle. A value of 0 means that there is no remote
79 * session established.
80 */
81 uint64_t net_handle;
82 /*
83 * This consumer is only set when the create_session_uri call is made.
84 * This contains the temporary information for a consumer output. Upon
85 * creation of the UST or kernel session, this consumer, if available, is
86 * copied into those sessions.
87 */
88 struct consumer_output *consumer;
89
90 /* Did at least ONE start command has been triggered?. */
91 unsigned int has_been_started:1;
92 /*
93 * Is the session active? Start trace command sets this to 1 and the stop
94 * command reset it to 0.
95 */
96 unsigned int active:1;
97
98 /* Snapshot representation in a session. */
99 struct snapshot snapshot;
100 /* Indicate if the session has to output the traces or not. */
101 unsigned int output_traces;
102 /*
103 * This session is in snapshot mode. This means that every channel enabled
104 * will be set in overwrite mode and mmap. It is considered exclusively for
105 * snapshot purposes.
106 */
107 unsigned int snapshot_mode;
108 /*
109 * Timer set when the session is created for live reading.
110 */
111 unsigned int live_timer;
112 /*
113 * Path where to keep the shared memory files.
114 */
115 char shm_path[PATH_MAX];
116 /*
117 * Node in ltt_sessions_ht_by_id.
118 */
119 struct lttng_ht_node_u64 node;
120 };
121
122 /* Prototypes */
123 int session_create(char *name, uid_t uid, gid_t gid);
124 int session_destroy(struct ltt_session *session);
125
126 void session_lock(struct ltt_session *session);
127 void session_lock_list(void);
128 void session_unlock(struct ltt_session *session);
129 void session_unlock_list(void);
130
131 struct ltt_session *session_find_by_name(const char *name);
132 struct ltt_session *session_find_by_id(uint64_t id);
133 struct ltt_session_list *session_get_list(void);
134
135 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
136
137 #endif /* _LTT_SESSION_H */
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