2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; only version 2
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
26 #include <lttng-sessiond-comm.h>
29 #include "hashtable.h"
32 #include "../hashtable/hash.h"
37 * No ltt_session.lock is taken here because those data structure are widely
38 * spread across the lttng-tools code base so before caling functions below
39 * that can read/write a session, the caller MUST acquire the session lock
40 * using session_lock() and session_unlock().
44 * Init tracing session list.
46 * Please see session.h for more explanation and correct usage of the list.
48 static struct ltt_session_list ltt_session_list
= {
49 .head
= CDS_LIST_HEAD_INIT(ltt_session_list
.head
),
50 .lock
= PTHREAD_MUTEX_INITIALIZER
,
55 * Add a ltt_session structure to the global list.
57 * The caller MUST acquire the session list lock before.
58 * Returns the unique identifier for the session.
60 static int add_session_list(struct ltt_session
*ls
)
62 cds_list_add(&ls
->list
, <t_session_list
.head
);
63 return ++ltt_session_list
.count
;
67 * Delete a ltt_session structure to the global list.
69 * The caller MUST acquire the session list lock before.
71 static void del_session_list(struct ltt_session
*ls
)
73 cds_list_del(&ls
->list
);
75 if (ltt_session_list
.count
> 0) {
76 ltt_session_list
.count
--;
81 * Return a pointer to the session list.
83 struct ltt_session_list
*session_get_list(void)
85 return <t_session_list
;
89 * Acquire session list lock
91 void session_lock_list(void)
93 pthread_mutex_lock(<t_session_list
.lock
);
97 * Release session list lock
99 void session_unlock_list(void)
101 pthread_mutex_unlock(<t_session_list
.lock
);
105 * Acquire session lock
107 void session_lock(struct ltt_session
*session
)
109 pthread_mutex_lock(&session
->lock
);
113 * Release session lock
115 void session_unlock(struct ltt_session
*session
)
117 pthread_mutex_unlock(&session
->lock
);
121 * Return a ltt_session structure ptr that matches name. If no session found,
122 * NULL is returned. This must be called with the session lock held using
123 * session_lock_list and session_unlock_list.
125 struct ltt_session
*session_find_by_name(char *name
)
127 struct ltt_session
*iter
;
129 DBG2("Trying to find session by name %s", name
);
131 cds_list_for_each_entry(iter
, <t_session_list
.head
, list
) {
132 if (strncmp(iter
->name
, name
, NAME_MAX
) == 0) {
144 * Delete session from the session list and free the memory.
146 * Return -1 if no session is found. On success, return 1;
148 int session_destroy(struct ltt_session
*session
)
151 if (session
== NULL
) {
152 ERR("Session pointer was null on session destroy");
156 DBG("Destroying session %s", session
->name
);
157 del_session_list(session
);
158 pthread_mutex_destroy(&session
->lock
);
165 * Create a brand new session and add it to the session list.
167 int session_create(char *name
, char *path
)
170 struct ltt_session
*new_session
;
172 new_session
= session_find_by_name(name
);
173 if (new_session
!= NULL
) {
174 ret
= LTTCOMM_EXIST_SESS
;
178 /* Allocate session data structure */
179 new_session
= zmalloc(sizeof(struct ltt_session
));
180 if (new_session
== NULL
) {
186 /* Define session name */
188 if (snprintf(new_session
->name
, NAME_MAX
, "%s", name
) < 0) {
193 ERR("No session name given");
198 /* Define session system path */
200 if (snprintf(new_session
->path
, PATH_MAX
, "%s", path
) < 0) {
205 ERR("No session path given");
210 /* Init kernel session */
211 new_session
->kernel_session
= NULL
;
212 new_session
->ust_session
= NULL
;
215 pthread_mutex_init(&new_session
->lock
, NULL
);
217 /* Add new session to the session list */
219 new_session
->uid
= add_session_list(new_session
);
220 session_unlock_list();
222 DBG("Tracing session %s created in %s with UID %d", name
, path
, new_session
->uid
);
228 if (new_session
!= NULL
) {