Fix uninitialized variable
[lttng-tools.git] / liblttngctl / liblttngctl.c
CommitLineData
826d496d 1/*
82a3637f
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2 * liblttngctl.c
3 *
4 * Linux Trace Toolkit Control Library
5 *
826d496d 6 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
fac6795d 7 *
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8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
12 *
13 * This library is distributed in the hope that it will be useful,
fac6795d 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
fac6795d
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21 */
22
23#define _GNU_SOURCE
24#include <errno.h>
25#include <grp.h>
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <unistd.h>
30
5b97ec60 31#include <lttng/lttng.h>
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32
33#include "liblttsessiondcomm.h"
34#include "lttngerr.h"
f3ed775e 35#include "lttng-share.h"
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36
37/* Socket to session daemon for communication */
38static int sessiond_socket;
39static char sessiond_sock_path[PATH_MAX];
40
41/* Communication structure to ltt-sessiond */
fac6795d 42static struct lttcomm_session_msg lsm;
5461b305 43static struct lttcomm_lttng_msg llm;
fac6795d 44
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45/* Variables */
46static char *tracing_group;
47static int connected;
48
49/*
ca95a216 50 * send_data_sessiond
fac6795d 51 *
e065084a 52 * Send lttcomm_session_msg to the session daemon.
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53 *
54 * On success, return 0
55 * On error, return error code
56 */
ca95a216 57static int send_data_sessiond(void)
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58{
59 int ret;
60
61 if (!connected) {
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62 ret = -ENOTCONN;
63 goto end;
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64 }
65
66 ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
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67
68end:
69 return ret;
70}
71
72/*
ca95a216 73 * recv_data_sessiond
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74 *
75 * Receive data from the sessiond socket.
76 *
77 * On success, return 0
78 * On error, return recv() error code
79 */
ca95a216 80static int recv_data_sessiond(void *buf, size_t len)
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81{
82 int ret;
83
84 if (!connected) {
85 ret = -ENOTCONN;
86 goto end;
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87 }
88
ca95a216 89 ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
fac6795d 90
e065084a 91end:
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92 return ret;
93}
94
95/*
947308c4 96 * Check if the specified group name exist.
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97 *
98 * If yes return 0, else return -1.
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99 */
100static int check_tracing_group(const char *grp_name)
101{
102 struct group *grp_tracing; /* no free(). See getgrnam(3) */
103 gid_t *grp_list;
104 int grp_list_size, grp_id, i;
105 int ret = -1;
106
107 /* Get GID of group 'tracing' */
108 grp_tracing = getgrnam(grp_name);
109 if (grp_tracing == NULL) {
110 /* NULL means not found also. getgrnam(3) */
111 if (errno != 0) {
112 perror("getgrnam");
113 }
114 goto end;
115 }
116
117 /* Get number of supplementary group IDs */
118 grp_list_size = getgroups(0, NULL);
119 if (grp_list_size < 0) {
120 perror("getgroups");
121 goto end;
122 }
123
124 /* Alloc group list of the right size */
125 grp_list = malloc(grp_list_size * sizeof(gid_t));
126 grp_id = getgroups(grp_list_size, grp_list);
127 if (grp_id < -1) {
128 perror("getgroups");
129 goto free_list;
130 }
131
132 for (i = 0; i < grp_list_size; i++) {
133 if (grp_list[i] == grp_tracing->gr_gid) {
134 ret = 0;
135 break;
136 }
137 }
138
139free_list:
140 free(grp_list);
141
142end:
143 return ret;
144}
145
146/*
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147 * Set sessiond socket path by putting it in the global sessiond_sock_path
148 * variable.
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149 */
150static int set_session_daemon_path(void)
151{
152 int ret;
153
154 /* Are we in the tracing group ? */
155 ret = check_tracing_group(tracing_group);
156 if (ret < 0 && getuid() != 0) {
157 if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
158 getenv("HOME")) < 0) {
159 return -ENOMEM;
160 }
161 } else {
162 strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
163 sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
164 }
165
166 return 0;
167}
168
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169/*
170 * Connect to the LTTng session daemon.
171 *
172 * On success, return 0. On error, return -1.
173 */
174static int connect_sessiond(void)
175{
176 int ret;
177
178 ret = set_session_daemon_path();
179 if (ret < 0) {
180 return ret;
181 }
182
183 /* Connect to the sesssion daemon */
184 ret = lttcomm_connect_unix_sock(sessiond_sock_path);
185 if (ret < 0) {
186 return ret;
187 }
188
189 sessiond_socket = ret;
190 connected = 1;
191
192 return 0;
193}
194
195/*
196 * Clean disconnect the session daemon.
197 */
198static int disconnect_sessiond(void)
199{
200 int ret = 0;
201
202 if (connected) {
203 ret = lttcomm_close_unix_sock(sessiond_socket);
204 sessiond_socket = 0;
205 connected = 0;
206 }
207
208 return ret;
209}
210
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211/*
212 * Reset the session message structure.
213 */
214static void reset_session_msg(void)
215{
216 memset(&lsm, 0, sizeof(struct lttcomm_session_msg));
217}
218
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219/*
220 * ask_sessiond
221 *
222 * Ask the session daemon a specific command and put the data into buf.
223 *
224 * Return size of data (only payload, not header).
225 */
226static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
227{
228 int ret;
229 size_t size;
230 void *data = NULL;
231
232 ret = connect_sessiond();
233 if (ret < 0) {
234 goto end;
235 }
236
237 lsm.cmd_type = lct;
238
239 /* Send command to session daemon */
240 ret = send_data_sessiond();
241 if (ret < 0) {
242 goto end;
243 }
244
245 /* Get header from data transmission */
246 ret = recv_data_sessiond(&llm, sizeof(llm));
247 if (ret < 0) {
248 goto end;
249 }
250
251 /* Check error code if OK */
252 if (llm.ret_code != LTTCOMM_OK) {
253 ret = -llm.ret_code;
254 goto end;
255 }
256
257 size = llm.data_size;
258 if (size == 0) {
7d29a247 259 ret = 0;
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260 goto end;
261 }
262
263 data = (void*) malloc(size);
264
265 /* Get payload data */
266 ret = recv_data_sessiond(data, size);
267 if (ret < 0) {
268 free(data);
269 goto end;
270 }
271
272 *buf = data;
273 ret = size;
274
275end:
276 disconnect_sessiond();
35a6fdb7 277 reset_session_msg();
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278 return ret;
279}
280
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281/*
282 * Copy domain to lttcomm_session_msg domain.
283 *
284 * Return -1 if the domain is unkown.
285 */
286static int copy_lttng_domain(struct lttng_domain *dom)
287{
288 switch (dom->type) {
289 case LTTNG_DOMAIN_KERNEL:
290 case LTTNG_DOMAIN_UST:
291 case LTTNG_DOMAIN_UST_EXEC_NAME:
292 case LTTNG_DOMAIN_UST_PID:
293 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
294 memcpy(&lsm.domain, dom, sizeof(struct lttng_domain));
295 return 0;
296 default:
297 return -1;
298 }
299}
300
1df4dedd 301/*
f3ed775e 302 * Start tracing for all trace of the session.
1df4dedd 303 */
38057ed1 304int lttng_start_tracing(const char *session_name)
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305{
306 strncpy(lsm.session_name, session_name, NAME_MAX);
307 return ask_sessiond(LTTNG_START_TRACE, NULL);
308}
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309
310/*
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311 * Stop tracing for all trace of the session.
312 */
38057ed1 313int lttng_stop_tracing(const char *session_name)
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314{
315 strncpy(lsm.session_name, session_name, NAME_MAX);
316 return ask_sessiond(LTTNG_STOP_TRACE, NULL);
317}
318
319/*
7d29a247 320 * lttng_add_context
1df4dedd 321 */
7d29a247 322int lttng_add_context(struct lttng_domain *domain,
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323 struct lttng_event_context *ctx, const char *event_name,
324 const char *channel_name)
d65106b1 325{
7d29a247
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326 int ret;
327
94cf3c47 328 if (channel_name != NULL) {
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329 strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX);
330 }
331
94cf3c47 332 if (event_name != NULL) {
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333 strncpy(lsm.u.context.event_name, event_name, NAME_MAX);
334 }
335
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336 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
337
338 switch (domain->type) {
339 case LTTNG_DOMAIN_KERNEL:
340 ret = ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL);
341 break;
342 case LTTNG_DOMAIN_UST:
343 ret = LTTCOMM_NOT_IMPLEMENTED;
344 break;
345 default:
346 ret = LTTCOMM_UNKNOWN_DOMAIN;
347 break;
348 };
349
350 return ret;
d65106b1
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351}
352
f3ed775e 353/*
7d29a247 354 * lttng_enable_event
f3ed775e 355 */
7d29a247 356int lttng_enable_event(struct lttng_domain *domain,
38057ed1 357 struct lttng_event *ev, const char *channel_name)
1df4dedd 358{
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359 int ret;
360
94cf3c47 361 if (channel_name == NULL) {
f3ed775e 362 strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
33a2b854 363 } else {
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364 strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX);
365 }
366
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367 switch (domain->type) {
368 case LTTNG_DOMAIN_KERNEL:
369 if (ev == NULL) {
370 ret = ask_sessiond(LTTNG_KERNEL_ENABLE_ALL_EVENT, NULL);
371 } else {
372 memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event));
373 ret = ask_sessiond(LTTNG_KERNEL_ENABLE_EVENT, NULL);
374 }
375 break;
376 case LTTNG_DOMAIN_UST:
377 ret = LTTCOMM_NOT_IMPLEMENTED;
378 break;
379 default:
380 ret = LTTCOMM_UNKNOWN_DOMAIN;
381 break;
382 };
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383
384 return ret;
1df4dedd
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385}
386
387/*
7d29a247 388 * Disable an event in the kernel tracer.
1df4dedd 389 */
38057ed1
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390int lttng_disable_event(struct lttng_domain *domain, const char *name,
391 const char *channel_name)
1df4dedd 392{
f3ed775e 393 int ret;
1df4dedd 394
94cf3c47 395 if (channel_name == NULL) {
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396 strncpy(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
397 } else {
398 strncpy(lsm.u.disable.channel_name, channel_name, NAME_MAX);
399 }
400
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401 switch (domain->type) {
402 case LTTNG_DOMAIN_KERNEL:
403 if (name == NULL) {
404 ret = ask_sessiond(LTTNG_KERNEL_DISABLE_ALL_EVENT, NULL);
405 } else {
406 strncpy(lsm.u.disable.name, name, NAME_MAX);
407 ret = ask_sessiond(LTTNG_KERNEL_DISABLE_EVENT, NULL);
408 }
409 break;
410 case LTTNG_DOMAIN_UST:
411 ret = LTTCOMM_NOT_IMPLEMENTED;
412 break;
413 default:
414 ret = LTTCOMM_UNKNOWN_DOMAIN;
415 break;
416 };
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417
418 return ret;
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419}
420
421/*
7d29a247 422 * Enable recording for a channel for the kernel tracer.
a5c5a2bd 423 */
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424int lttng_enable_channel(struct lttng_domain *domain,
425 struct lttng_channel *chan)
a5c5a2bd 426{
7d29a247 427 int ret;
8c0faa1d 428
f3ed775e 429 memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
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430
431 switch (domain->type) {
432 case LTTNG_DOMAIN_KERNEL:
433 ret = ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL);
434 break;
435 case LTTNG_DOMAIN_UST:
436 ret = LTTCOMM_NOT_IMPLEMENTED;
437 break;
438 default:
439 ret = LTTCOMM_UNKNOWN_DOMAIN;
440 break;
441 };
442
443 return ret;
8c0faa1d 444}
1df4dedd 445
2ef84c95 446/*
7d29a247 447 * Disable recording for the channel for the kernel tracer.
2ef84c95 448 */
38057ed1 449int lttng_disable_channel(struct lttng_domain *domain, const char *name)
2ef84c95 450{
7d29a247 451 int ret;
2ef84c95 452
7d29a247 453 strncpy(lsm.u.disable.channel_name, name, NAME_MAX);
1df4dedd 454
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455 switch (domain->type) {
456 case LTTNG_DOMAIN_KERNEL:
457 ret = ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL);
458 break;
459 case LTTNG_DOMAIN_UST:
460 ret = LTTCOMM_NOT_IMPLEMENTED;
461 break;
462 default:
463 ret = LTTCOMM_UNKNOWN_DOMAIN;
464 break;
465 };
ca95a216 466
7d29a247 467 return ret;
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468}
469
fac6795d 470/*
9f19cc17 471 * List all available kernel events.
fac6795d 472 *
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473 * Return the size (bytes) of the list and set the event_list array.
474 * On error, return negative value.
fac6795d 475 */
9f19cc17 476int lttng_list_kernel_events(struct lttng_event **events)
fac6795d 477{
ca95a216 478 int ret;
fac6795d 479
9f19cc17 480 ret = ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) events);
fac6795d 481
9f19cc17 482 return ret / sizeof(struct lttng_event);
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483}
484
1657e9bb 485/*
7d29a247 486 * Return a human readable string of code
1657e9bb 487 */
7d29a247 488const char *lttng_get_readable_code(int code)
1657e9bb 489{
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490 if (code > -LTTCOMM_OK) {
491 return "Ended with errors";
1657e9bb
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492 }
493
7d29a247 494 return lttcomm_get_readable_code(code);
1657e9bb
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495}
496
aaf97519 497/*
894be886 498 * Create a brand new session using name.
aaf97519 499 */
38057ed1 500int lttng_create_session(const char *name, const char *path)
aaf97519 501{
947308c4 502 strncpy(lsm.session_name, name, NAME_MAX);
f3ed775e 503 strncpy(lsm.path, path, PATH_MAX);
947308c4 504 return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
8028d920
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505}
506
507/*
8028d920
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508 * Destroy session using name.
509 */
38057ed1 510int lttng_destroy_session(const char *name)
8028d920 511{
f3ed775e 512 strncpy(lsm.session_name, name, NAME_MAX);
947308c4 513 return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
aaf97519
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514}
515
57167058 516/*
57167058
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517 * Ask the session daemon for all available sessions.
518 *
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519 * Return number of session.
520 * On error, return negative value.
57167058 521 */
ca95a216 522int lttng_list_sessions(struct lttng_session **sessions)
57167058 523{
ca95a216 524 int ret;
57167058 525
ca95a216 526 ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
57167058 527 if (ret < 0) {
ca95a216 528 return ret;
57167058
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529 }
530
ca95a216 531 return ret / sizeof(struct lttng_session);
57167058
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532}
533
9f19cc17
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534/*
535 * List domain of a session.
536 */
537int lttng_list_domains(const char *session_name, struct lttng_domain **domains)
538{
539 int ret;
540
541 strncpy(lsm.session_name, session_name, NAME_MAX);
542 ret = ask_sessiond(LTTNG_LIST_DOMAINS, (void**) domains);
543 if (ret < 0) {
544 return ret;
545 }
546
547 return ret / sizeof(struct lttng_domain);
548}
549
550/*
551 * List channels of a session
552 */
553int lttng_list_channels(struct lttng_domain *domain,
554 const char *session_name, struct lttng_channel **channels)
555{
556 int ret;
557
558 strncpy(lsm.session_name, session_name, NAME_MAX);
559 ret = copy_lttng_domain(domain);
560 if (ret < 0) {
561 return -LTTCOMM_UNKNOWN_DOMAIN;
562 }
563
564 ret = ask_sessiond(LTTNG_LIST_CHANNELS, (void**) channels);
565 if (ret < 0) {
566 return ret;
567 }
568
569 return ret / sizeof(struct lttng_channel);
570}
571
572/*
573 * List events of a session channel.
574 */
575int lttng_list_events(struct lttng_domain *domain,
576 const char *session_name, const char *channel_name,
577 struct lttng_event **events)
578{
579 int ret;
580
581 strncpy(lsm.session_name, session_name, NAME_MAX);
582 strncpy(lsm.u.list.channel_name, channel_name, NAME_MAX);
583 ret = copy_lttng_domain(domain);
584 if (ret < 0) {
585 return -LTTCOMM_UNKNOWN_DOMAIN;
586 }
587
588 ret = ask_sessiond(LTTNG_LIST_EVENTS, (void**) events);
589 if (ret < 0) {
590 return ret;
591 }
592
593 return ret / sizeof(struct lttng_event);
594}
595
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596/*
597 * Set session name for the current lsm.
598 */
38057ed1 599void lttng_set_session_name(const char *name)
e8be5f4f 600{
f3ed775e 601 strncpy(lsm.session_name, name, NAME_MAX);
e8be5f4f
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602}
603
fac6795d
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604/*
605 * lttng_set_tracing_group
606 *
607 * Set tracing group variable with name. This function
608 * allocate memory pointed by tracing_group.
609 */
610int lttng_set_tracing_group(const char *name)
611{
612 if (asprintf(&tracing_group, "%s", name) < 0) {
613 return -ENOMEM;
614 }
615
616 return 0;
617}
618
619/*
620 * lttng_check_session_daemon
621 *
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622 * Yes, return 1
623 * No, return 0
624 * Error, return negative value
fac6795d 625 */
947308c4 626int lttng_session_daemon_alive(void)
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627{
628 int ret;
629
630 ret = set_session_daemon_path();
631 if (ret < 0) {
947308c4 632 /* Error */
fac6795d
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633 return ret;
634 }
635
636 /* If socket exist, we consider the daemon started */
637 ret = access(sessiond_sock_path, F_OK);
638 if (ret < 0) {
947308c4
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639 /* Not alive */
640 return 0;
fac6795d
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641 }
642
947308c4
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643 /* Is alive */
644 return 1;
fac6795d
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645}
646
647/*
648 * lib constructor
649 */
650static void __attribute__((constructor)) init()
651{
652 /* Set default session group */
64a23ac4 653 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
fac6795d 654}
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