thread_manage_apps: update and comment socket handling
[lttng-tools.git] / ltt-sessiond / session.c
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1/*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
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6 * as published by the Free Software Foundation; only version 2
7 * of the License.
91d76f53 8 *
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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.
13 *
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.
17 */
18
19#define _GNU_SOURCE
6c9cc2ab 20#include <limits.h>
b5541356 21#include <pthread.h>
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22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
b082db07 25#include <time.h>
5b74c7b1 26#include <urcu/list.h>
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27
28#include "lttngerr.h"
29#include "session.h"
30
8c0faa1d 31/*
b5541356 32 * NOTES:
8c0faa1d 33 *
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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
37 * using lock_session() and unlock_session().
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 */
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45static struct ltt_session_list ltt_session_list = {
46 .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
47 .lock = PTHREAD_MUTEX_INITIALIZER,
48 .count = 0,
49};
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50
51/*
52 * add_session_list
53 *
54 * Add a ltt_session structure to the global list.
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55 *
56 * The caller MUST acquire the session list lock before.
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57 */
58static void add_session_list(struct ltt_session *ls)
59{
60 cds_list_add(&ls->list, &ltt_session_list.head);
b5541356 61 ltt_session_list.count++;
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62}
63
64/*
65 * del_session_list
66 *
67 * Delete a ltt_session structure to the global list.
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68 *
69 * The caller MUST acquire the session list lock before.
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70 */
71static void del_session_list(struct ltt_session *ls)
72{
73 cds_list_del(&ls->list);
74 /* Sanity check */
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75 if (ltt_session_list.count > 0) {
76 ltt_session_list.count--;
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77 }
78}
79
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80/*
81 * get_session_list
82 *
83 * Return a pointer to the session list.
84 */
85struct ltt_session_list *get_session_list(void)
86{
87 return &ltt_session_list;
88}
89
90/*
6c9cc2ab 91 * Acquire session list lock
b5541356 92 */
6c9cc2ab 93void lock_session_list(void)
b5541356 94{
6c9cc2ab 95 pthread_mutex_lock(&ltt_session_list.lock);
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96}
97
98/*
6c9cc2ab 99 * Release session list lock
b5541356 100 */
6c9cc2ab 101void unlock_session_list(void)
b5541356 102{
6c9cc2ab 103 pthread_mutex_unlock(&ltt_session_list.lock);
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104}
105
106/*
6c9cc2ab 107 * Acquire session lock
b5541356 108 */
6c9cc2ab 109void lock_session(struct ltt_session *session)
b5541356 110{
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111 pthread_mutex_lock(&session->lock);
112}
b5541356 113
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114/*
115 * Release session lock
116 */
117void unlock_session(struct ltt_session *session)
118{
119 pthread_mutex_unlock(&session->lock);
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120}
121
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122/*
123 * find_session_by_name
124 *
125 * Return a ltt_session structure ptr that matches name.
126 * If no session found, NULL is returned.
127 */
128struct ltt_session *find_session_by_name(char *name)
129{
130 int found = 0;
131 struct ltt_session *iter;
132
6c9cc2ab 133 lock_session_list();
5b74c7b1 134 cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
1b110e1b 135 if (strncmp(iter->name, name, NAME_MAX) == 0) {
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136 found = 1;
137 break;
138 }
139 }
6c9cc2ab 140 unlock_session_list();
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141
142 if (!found) {
143 iter = NULL;
144 }
145
146 return iter;
147}
148
149/*
150 * destroy_session
151 *
b5541356 152 * Delete session from the session list and free the memory.
5b74c7b1 153 *
b5541356 154 * Return -1 if no session is found. On success, return 1;
5b74c7b1 155 */
f3ed775e 156int destroy_session(char *name)
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157{
158 int found = -1;
af9737e9 159 struct ltt_session *iter, *tmp;
5b74c7b1 160
6c9cc2ab 161 lock_session_list();
af9737e9 162 cds_list_for_each_entry_safe(iter, tmp, &ltt_session_list.head, list) {
f3ed775e 163 if (strcmp(iter->name, name) == 0) {
e07ae692 164 DBG("Destroying session %s", iter->name);
5b74c7b1 165 del_session_list(iter);
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166 free(iter->name);
167 free(iter->path);
168 pthread_mutex_destroy(&iter->lock);
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169 free(iter);
170 found = 1;
171 break;
172 }
173 }
6c9cc2ab 174 unlock_session_list();
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175
176 return found;
177}
178
179/*
180 * create_session
181 *
b5541356 182 * Create a brand new session and add it to the session list.
5b74c7b1 183 */
f3ed775e 184int create_session(char *name, char *path)
5b74c7b1 185{
f3ed775e 186 int ret;
5b74c7b1 187 struct ltt_session *new_session;
e07ae692 188
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189 new_session = find_session_by_name(name);
190 if (new_session != NULL) {
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191 ret = -EEXIST;
192 goto error_exist;
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193 }
194
195 /* Allocate session data structure */
196 new_session = malloc(sizeof(struct ltt_session));
197 if (new_session == NULL) {
198 perror("malloc");
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199 ret = -ENOMEM;
200 goto error_malloc;
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201 }
202
f3ed775e 203 /* Define session name */
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204 if (name != NULL) {
205 if (asprintf(&new_session->name, "%s", name) < 0) {
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206 ret = -ENOMEM;
207 goto error_asprintf;
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208 }
209 } else {
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210 ERR("No session name given");
211 ret = -1;
212 goto error;
213 }
214
215 /* Define session system path */
216 if (path != NULL) {
d6175221 217 if (asprintf(&new_session->path, "%s", path) < 0) {
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218 ret = -ENOMEM;
219 goto error_asprintf;
5b74c7b1 220 }
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221 } else {
222 ERR("No session path given");
223 ret = -1;
224 goto error;
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225 }
226
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227 /* Init kernel session */
228 new_session->kernel_session = NULL;
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229
230 /* Init list */
231 CDS_INIT_LIST_HEAD(&new_session->ust_traces);
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232
233 /* Set trace list counter */
234 new_session->ust_trace_count = 0;
5b74c7b1 235
b5541356 236 /* Add new session to the session list */
6c9cc2ab 237 lock_session_list();
5b74c7b1 238 add_session_list(new_session);
6c9cc2ab 239 unlock_session_list();
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240
241 /* Init lock */
242 pthread_mutex_init(&new_session->lock, NULL);
5b74c7b1 243
b5541356 244 DBG("Tracing session %s created in %s", new_session->name, new_session->path);
b082db07 245
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246 return 0;
247
248error:
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249error_asprintf:
250 if (new_session != NULL) {
251 free(new_session);
252 }
5b74c7b1 253
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254error_exist:
255error_malloc:
256 return ret;
5b74c7b1 257}
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