Notify java agent of enabled application contexts
[lttng-tools.git] / src / bin / lttng-relayd / viewer-session.c
1 /*
2 * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
3 * David Goulet <dgoulet@efficios.com>
4 * 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License, version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #define _LGPL_SOURCE
21 #include <common/common.h>
22 #include <urcu/rculist.h>
23
24 #include "lttng-relayd.h"
25 #include "ctf-trace.h"
26 #include "session.h"
27 #include "viewer-session.h"
28 #include "viewer-stream.h"
29 #include "stream.h"
30
31 struct relay_viewer_session *viewer_session_create(void)
32 {
33 struct relay_viewer_session *vsession;
34
35 vsession = zmalloc(sizeof(*vsession));
36 if (!vsession) {
37 goto end;
38 }
39 CDS_INIT_LIST_HEAD(&vsession->session_list);
40 end:
41 return vsession;
42 }
43
44 /* The existence of session must be guaranteed by the caller. */
45 int viewer_session_attach(struct relay_viewer_session *vsession,
46 struct relay_session *session)
47 {
48 int ret = 0;
49
50 /* Will not fail, as per the ownership guarantee. */
51 if (!session_get(session)) {
52 ret = -1;
53 goto end;
54 }
55 pthread_mutex_lock(&session->lock);
56 if (session->viewer_attached) {
57 ret = -1;
58 } else {
59 session->viewer_attached = true;
60 }
61
62 if (!ret) {
63 pthread_mutex_lock(&vsession->session_list_lock);
64 /* Ownership is transfered to the list. */
65 cds_list_add_rcu(&session->viewer_session_node,
66 &vsession->session_list);
67 pthread_mutex_unlock(&vsession->session_list_lock);
68 } else {
69 /* Put our local ref. */
70 session_put(session);
71 }
72 /* Safe since we know the session exists. */
73 pthread_mutex_unlock(&session->lock);
74 end:
75 return ret;
76 }
77
78 /* The existence of session must be guaranteed by the caller. */
79 static int viewer_session_detach(struct relay_viewer_session *vsession,
80 struct relay_session *session)
81 {
82 int ret = 0;
83
84 pthread_mutex_lock(&session->lock);
85 if (!session->viewer_attached) {
86 ret = -1;
87 } else {
88 session->viewer_attached = false;
89 }
90
91 if (!ret) {
92 pthread_mutex_lock(&vsession->session_list_lock);
93 cds_list_del_rcu(&session->viewer_session_node);
94 pthread_mutex_unlock(&vsession->session_list_lock);
95 /* Release reference held by the list. */
96 session_put(session);
97 }
98 /* Safe since we know the session exists. */
99 pthread_mutex_unlock(&session->lock);
100 return ret;
101 }
102
103 void viewer_session_destroy(struct relay_viewer_session *vsession)
104 {
105 free(vsession);
106 }
107
108 void viewer_session_close(struct relay_viewer_session *vsession)
109 {
110 struct relay_session *session;
111
112 rcu_read_lock();
113 cds_list_for_each_entry_rcu(session,
114 &vsession->session_list, viewer_session_node) {
115 struct lttng_ht_iter iter;
116 struct relay_viewer_stream *vstream;
117
118 /*
119 * TODO: improvement: create more efficient list of
120 * vstream per session.
121 */
122 cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter,
123 vstream, stream_n.node) {
124 if (!viewer_stream_get(vstream)) {
125 continue;
126 }
127 if (vstream->stream->trace->session != session) {
128 viewer_stream_put(vstream);
129 continue;
130 }
131 /* Put local reference. */
132 viewer_stream_put(vstream);
133 /*
134 * We have reached one of the viewer stream's lifetime
135 * end condition.
136 */
137 viewer_stream_put(vstream);
138 }
139
140 viewer_session_detach(vsession, session);
141 }
142 rcu_read_unlock();
143 }
144
145 /*
146 * Check if a connection is attached to a session.
147 * Return 1 if attached, 0 if not attached, a negative value on error.
148 */
149 int viewer_session_is_attached(struct relay_viewer_session *vsession,
150 struct relay_session *session)
151 {
152 struct relay_session *iter;
153 int found = 0;
154
155 pthread_mutex_lock(&session->lock);
156 if (!vsession) {
157 goto end;
158 }
159 if (!session->viewer_attached) {
160 goto end;
161 }
162 rcu_read_lock();
163 cds_list_for_each_entry_rcu(iter,
164 &vsession->session_list,
165 viewer_session_node) {
166 if (session == iter) {
167 found = 1;
168 goto end_rcu_unlock;
169 }
170 }
171 end_rcu_unlock:
172 rcu_read_unlock();
173 end:
174 pthread_mutex_unlock(&session->lock);
175 return found;
176 }
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