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.
27 #include <common/common.h>
28 #include <common/sessiond-comm/sessiond-comm.h>
35 * No ltt_session.lock is taken here because those data structure are widely
36 * spread across the lttng-tools code base so before caling functions below
37 * that can read/write a session, the caller MUST acquire the session lock
38 * using session_lock() and session_unlock().
42 * Init tracing session list.
44 * Please see session.h for more explanation and correct usage of the list.
46 static struct ltt_session_list ltt_session_list
= {
47 .head
= CDS_LIST_HEAD_INIT(ltt_session_list
.head
),
48 .lock
= PTHREAD_MUTEX_INITIALIZER
,
53 * Add a ltt_session structure to the global list.
55 * The caller MUST acquire the session list lock before.
56 * Returns the unique identifier for the session.
58 static uint64_t add_session_list(struct ltt_session
*ls
)
62 cds_list_add(&ls
->list
, <t_session_list
.head
);
63 return ltt_session_list
.next_uuid
++;
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
)
75 cds_list_del(&ls
->list
);
79 * Return a pointer to the session list.
81 struct ltt_session_list
*session_get_list(void)
83 return <t_session_list
;
87 * Acquire session list lock
89 void session_lock_list(void)
91 pthread_mutex_lock(<t_session_list
.lock
);
95 * Release session list lock
97 void session_unlock_list(void)
99 pthread_mutex_unlock(<t_session_list
.lock
);
103 * Acquire session lock
105 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
)
119 pthread_mutex_unlock(&session
->lock
);
123 * Return a ltt_session structure ptr that matches name. If no session found,
124 * NULL is returned. This must be called with the session lock held using
125 * session_lock_list and session_unlock_list.
127 struct ltt_session
*session_find_by_name(char *name
)
129 struct ltt_session
*iter
;
133 DBG2("Trying to find session by name %s", name
);
135 cds_list_for_each_entry(iter
, <t_session_list
.head
, list
) {
136 if (strncmp(iter
->name
, name
, NAME_MAX
) == 0) {
148 * Delete session from the session list and free the memory.
150 * Return -1 if no session is found. On success, return 1;
151 * Should *NOT* be called with RCU read-side lock held.
153 int session_destroy(struct ltt_session
*session
)
158 DBG("Destroying session %s", session
->name
);
159 del_session_list(session
);
160 pthread_mutex_destroy(&session
->lock
);
162 consumer_destroy_output(session
->consumer
);
163 snapshot_destroy(&session
->snapshot
);
170 * Create a brand new session and add it to the session list.
172 int session_create(char *name
, uid_t uid
, gid_t gid
)
175 struct ltt_session
*new_session
;
177 /* Allocate session data structure */
178 new_session
= zmalloc(sizeof(struct ltt_session
));
179 if (new_session
== NULL
) {
181 ret
= LTTNG_ERR_FATAL
;
185 /* Define session name */
187 if (snprintf(new_session
->name
, NAME_MAX
, "%s", name
) < 0) {
188 ret
= LTTNG_ERR_FATAL
;
192 ERR("No session name given");
193 ret
= LTTNG_ERR_FATAL
;
197 ret
= gethostname(new_session
->hostname
, sizeof(new_session
->hostname
));
199 if (errno
== ENAMETOOLONG
) {
200 new_session
->hostname
[sizeof(new_session
->hostname
) - 1] = '\0';
202 ret
= LTTNG_ERR_FATAL
;
207 /* Init kernel session */
208 new_session
->kernel_session
= NULL
;
209 new_session
->ust_session
= NULL
;
212 pthread_mutex_init(&new_session
->lock
, NULL
);
214 new_session
->uid
= uid
;
215 new_session
->gid
= gid
;
217 ret
= snapshot_init(&new_session
->snapshot
);
219 ret
= LTTNG_ERR_NOMEM
;
223 /* Add new session to the session list */
225 new_session
->id
= add_session_list(new_session
);
226 session_unlock_list();
229 * Consumer is let to NULL since the create_session_uri command will set it
230 * up and, if valid, assign it to the session.
233 DBG("Tracing session %s created with ID %" PRIu64
" by UID %d GID %d",
234 name
, new_session
->id
, new_session
->uid
, new_session
->gid
);
247 * Check if the UID or GID match the session. Root user has access to all
250 int session_access_ok(struct ltt_session
*session
, uid_t uid
, gid_t gid
)
254 if (uid
!= session
->uid
&& gid
!= session
->gid
&& uid
!= 0) {