Add snapshot command to lttng UI
[lttng-tools.git] / src / bin / lttng-sessiond / session.c
CommitLineData
5b74c7b1
DG
1/*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
d14d33bf
AM
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.
91d76f53 7 *
5b74c7b1
DG
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
d14d33bf 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
5b74c7b1
DG
11 * GNU General Public License for more details.
12 *
d14d33bf
AM
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.
5b74c7b1
DG
16 */
17
18#define _GNU_SOURCE
6c9cc2ab 19#include <limits.h>
5b74c7b1
DG
20#include <stdio.h>
21#include <stdlib.h>
22#include <string.h>
a304c14c 23#include <sys/stat.h>
f6a9efaa 24#include <urcu.h>
5b74c7b1 25
990570ed 26#include <common/common.h>
db758600 27#include <common/sessiond-comm/sessiond-comm.h>
1e307fab 28
5b74c7b1
DG
29#include "session.h"
30
8c0faa1d 31/*
b5541356 32 * NOTES:
8c0faa1d 33 *
b5541356
DG
34 * No ltt_session.lock is taken here because those data structure are widely
35 * spread across the lttng-tools code base so before caling functions below
36 * that can read/write a session, the caller MUST acquire the session lock
54d01ffb 37 * using session_lock() and session_unlock().
8c0faa1d 38 */
8c0faa1d 39
5b74c7b1 40/*
b5541356 41 * Init tracing session list.
5b74c7b1 42 *
b5541356 43 * Please see session.h for more explanation and correct usage of the list.
5b74c7b1 44 */
b5541356
DG
45static struct ltt_session_list ltt_session_list = {
46 .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
47 .lock = PTHREAD_MUTEX_INITIALIZER,
a24f7994 48 .next_uuid = 0,
b5541356 49};
5b74c7b1
DG
50
51/*
050349bb 52 * Add a ltt_session structure to the global list.
5b74c7b1 53 *
050349bb 54 * The caller MUST acquire the session list lock before.
44e96653 55 * Returns the unique identifier for the session.
5b74c7b1 56 */
fc4705fe 57static unsigned int add_session_list(struct ltt_session *ls)
5b74c7b1 58{
0525e9ae
DG
59 assert(ls);
60
5b74c7b1 61 cds_list_add(&ls->list, &ltt_session_list.head);
a24f7994 62 return ltt_session_list.next_uuid++;
5b74c7b1
DG
63}
64
65/*
050349bb 66 * Delete a ltt_session structure to the global list.
b5541356 67 *
050349bb 68 * The caller MUST acquire the session list lock before.
5b74c7b1
DG
69 */
70static void del_session_list(struct ltt_session *ls)
71{
0525e9ae
DG
72 assert(ls);
73
5b74c7b1 74 cds_list_del(&ls->list);
5b74c7b1
DG
75}
76
b5541356 77/*
050349bb 78 * Return a pointer to the session list.
b5541356 79 */
54d01ffb 80struct ltt_session_list *session_get_list(void)
b5541356
DG
81{
82 return &ltt_session_list;
83}
84
85/*
6c9cc2ab 86 * Acquire session list lock
b5541356 87 */
54d01ffb 88void session_lock_list(void)
b5541356 89{
6c9cc2ab 90 pthread_mutex_lock(&ltt_session_list.lock);
b5541356
DG
91}
92
93/*
6c9cc2ab 94 * Release session list lock
b5541356 95 */
54d01ffb 96void session_unlock_list(void)
b5541356 97{
6c9cc2ab 98 pthread_mutex_unlock(&ltt_session_list.lock);
b5541356
DG
99}
100
101/*
6c9cc2ab 102 * Acquire session lock
b5541356 103 */
54d01ffb 104void session_lock(struct ltt_session *session)
b5541356 105{
0525e9ae
DG
106 assert(session);
107
6c9cc2ab
DG
108 pthread_mutex_lock(&session->lock);
109}
b5541356 110
6c9cc2ab
DG
111/*
112 * Release session lock
113 */
54d01ffb 114void session_unlock(struct ltt_session *session)
6c9cc2ab 115{
0525e9ae
DG
116 assert(session);
117
6c9cc2ab 118 pthread_mutex_unlock(&session->lock);
b5541356
DG
119}
120
5b74c7b1 121/*
74babd95
DG
122 * Return a ltt_session structure ptr that matches name. If no session found,
123 * NULL is returned. This must be called with the session lock held using
124 * session_lock_list and session_unlock_list.
5b74c7b1 125 */
54d01ffb 126struct ltt_session *session_find_by_name(char *name)
5b74c7b1 127{
5b74c7b1
DG
128 struct ltt_session *iter;
129
0525e9ae
DG
130 assert(name);
131
5f822d0a
DG
132 DBG2("Trying to find session by name %s", name);
133
5b74c7b1 134 cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
1b110e1b 135 if (strncmp(iter->name, name, NAME_MAX) == 0) {
74babd95 136 goto found;
5b74c7b1
DG
137 }
138 }
139
74babd95 140 iter = NULL;
5b74c7b1 141
74babd95 142found:
5b74c7b1
DG
143 return iter;
144}
145
146/*
050349bb 147 * Delete session from the session list and free the memory.
5b74c7b1 148 *
050349bb 149 * Return -1 if no session is found. On success, return 1;
36b588ed 150 * Should *NOT* be called with RCU read-side lock held.
5b74c7b1 151 */
271933a4 152int session_destroy(struct ltt_session *session)
5b74c7b1 153{
271933a4 154 /* Safety check */
0525e9ae 155 assert(session);
271933a4
DG
156
157 DBG("Destroying session %s", session->name);
158 del_session_list(session);
271933a4 159 pthread_mutex_destroy(&session->lock);
07424f16 160
07424f16 161 consumer_destroy_output(session->consumer);
271933a4 162 free(session);
5b74c7b1 163
f73fabfd 164 return LTTNG_OK;
5b74c7b1
DG
165}
166
167/*
050349bb 168 * Create a brand new session and add it to the session list.
5b74c7b1 169 */
dec56f6c 170int session_create(char *name, uid_t uid, gid_t gid)
5b74c7b1 171{
f3ed775e 172 int ret;
5b74c7b1 173 struct ltt_session *new_session;
e07ae692 174
5b74c7b1 175 /* Allocate session data structure */
ba7f0ae5 176 new_session = zmalloc(sizeof(struct ltt_session));
5b74c7b1 177 if (new_session == NULL) {
df0f840b 178 PERROR("zmalloc");
f73fabfd 179 ret = LTTNG_ERR_FATAL;
f3ed775e 180 goto error_malloc;
5b74c7b1
DG
181 }
182
f3ed775e 183 /* Define session name */
5b74c7b1 184 if (name != NULL) {
74babd95 185 if (snprintf(new_session->name, NAME_MAX, "%s", name) < 0) {
f73fabfd 186 ret = LTTNG_ERR_FATAL;
f3ed775e 187 goto error_asprintf;
5b74c7b1
DG
188 }
189 } else {
f3ed775e 190 ERR("No session name given");
f73fabfd 191 ret = LTTNG_ERR_FATAL;
f3ed775e
DG
192 goto error;
193 }
194
1d4b027a
DG
195 /* Init kernel session */
196 new_session->kernel_session = NULL;
f6a9efaa 197 new_session->ust_session = NULL;
1657e9bb 198
0177d773
DG
199 /* Init lock */
200 pthread_mutex_init(&new_session->lock, NULL);
5b74c7b1 201
6df2e2c9
MD
202 new_session->uid = uid;
203 new_session->gid = gid;
204
b5541356 205 /* Add new session to the session list */
54d01ffb 206 session_lock_list();
a991f516 207 new_session->id = add_session_list(new_session);
54d01ffb 208 session_unlock_list();
b5541356 209
a4b92340
DG
210 /*
211 * Consumer is let to NULL since the create_session_uri command will set it
212 * up and, if valid, assign it to the session.
213 */
214
dec56f6c
DG
215 DBG("Tracing session %s created with ID %u by UID %d GID %d", name,
216 new_session->id, new_session->uid, new_session->gid);
b082db07 217
f73fabfd 218 return LTTNG_OK;
5b74c7b1
DG
219
220error:
f3ed775e 221error_asprintf:
0e428499 222 free(new_session);
5b74c7b1 223
f3ed775e
DG
224error_malloc:
225 return ret;
5b74c7b1 226}
2f77fc4b
DG
227
228/*
229 * Check if the UID or GID match the session. Root user has access to all
230 * sessions.
231 */
232int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid)
233{
234 assert(session);
235
236 if (uid != session->uid && gid != session->gid && uid != 0) {
237 return 0;
238 } else {
239 return 1;
240 }
241}
This page took 0.07237 seconds and 4 git commands to generate.