Add kernel open metadata support to session daemon
[lttng-tools.git] / liblttngctl / liblttngctl.c
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1/*
2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
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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
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
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.
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17 */
18
19#define _GNU_SOURCE
20#include <errno.h>
21#include <grp.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <unistd.h>
26
5b97ec60 27#include <lttng/lttng.h>
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28
29#include "liblttsessiondcomm.h"
30#include "lttngerr.h"
31
32/* Socket to session daemon for communication */
33static int sessiond_socket;
34static char sessiond_sock_path[PATH_MAX];
35
36/* Communication structure to ltt-sessiond */
fac6795d 37static struct lttcomm_session_msg lsm;
5461b305 38static struct lttcomm_lttng_msg llm;
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39
40/* Prototypes */
41static int check_tracing_group(const char *grp_name);
6abb15de 42static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf);
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43static int recv_data_sessiond(void *buf, size_t len);
44static int send_data_sessiond(void);
fac6795d 45static int set_session_daemon_path(void);
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46
47/* Variables */
48static char *tracing_group;
49static int connected;
50
51/*
ca95a216 52 * send_data_sessiond
fac6795d 53 *
e065084a 54 * Send lttcomm_session_msg to the session daemon.
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55 *
56 * On success, return 0
57 * On error, return error code
58 */
ca95a216 59static int send_data_sessiond(void)
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60{
61 int ret;
62
63 if (!connected) {
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64 ret = -ENOTCONN;
65 goto end;
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66 }
67
68 ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
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69
70end:
71 return ret;
72}
73
74/*
ca95a216 75 * recv_data_sessiond
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76 *
77 * Receive data from the sessiond socket.
78 *
79 * On success, return 0
80 * On error, return recv() error code
81 */
ca95a216 82static int recv_data_sessiond(void *buf, size_t len)
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83{
84 int ret;
85
86 if (!connected) {
87 ret = -ENOTCONN;
88 goto end;
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89 }
90
ca95a216 91 ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
fac6795d 92 if (ret < 0) {
e065084a 93 goto end;
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94 }
95
e065084a 96end:
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97 return ret;
98}
99
100/*
ca95a216 101 * ask_sessiond
fac6795d 102 *
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103 * Ask the session daemon a specific command
104 * and put the data into buf.
105 *
106 * Return size of data (only payload, not header).
fac6795d 107 */
6abb15de 108static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
fac6795d 109{
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110 int ret;
111 size_t size;
112 void *data = NULL;
ca95a216 113
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114 ret = lttng_connect_sessiond();
115 if (ret < 0) {
116 goto end;
117 }
118
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119 lsm.cmd_type = lct;
120
121 /* Send command to session daemon */
122 ret = send_data_sessiond();
123 if (ret < 0) {
124 goto end;
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125 }
126
ca95a216 127 /* Get header from data transmission */
5461b305 128 ret = recv_data_sessiond(&llm, sizeof(llm));
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129 if (ret < 0) {
130 goto end;
131 }
fac6795d 132
ca95a216 133 /* Check error code if OK */
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134 if (llm.ret_code != LTTCOMM_OK) {
135 ret = -llm.ret_code;
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136 goto end;
137 }
fac6795d 138
5461b305 139 size = llm.trace_name_offset + llm.data_size;
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140 if (size == 0) {
141 goto end;
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142 }
143
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144 data = (void*) malloc(size);
145
146 /* Get payload data */
147 ret = recv_data_sessiond(data, size);
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148 if (ret < 0) {
149 goto end;
150 }
151
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152 *buf = data;
153 ret = size;
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154
155end:
7442b2ba 156 lttng_disconnect_sessiond();
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157 return ret;
158}
159
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160/*
161 * BEGIN KERNEL CONTROL
162 */
163
164/*
165 * lttng_kernel_enable_event
166 *
167 * Enable an event in the kernel tracer.
168 */
169int lttng_kernel_enable_event(char *event_name)
170{
171 strncpy(lsm.u.event.event_name, event_name, NAME_MAX);
172 return ask_sessiond(KERNEL_ENABLE_EVENT, NULL);
173}
174
175/*
176 * lttng_kernel_disable_event
177 *
178 * Disable an event in the kernel tracer.
179 */
180int lttng_kernel_disable_event(char *event_name)
181{
182 strncpy(lsm.u.event.event_name, event_name, NAME_MAX);
183 return ask_sessiond(KERNEL_DISABLE_EVENT, NULL);
184}
185
186/*
187 * lttng_kernel_create_session
188 *
189 * Create a session in the kernel tracer.
190 */
191int lttng_kernel_create_session(void)
192{
193 return ask_sessiond(KERNEL_CREATE_SESSION, NULL);
194}
195
196/*
197 * lttng_kernel_create_channel
198 *
199 * Create a channel in the kernel tracer.
200 */
20fe2104 201int lttng_kernel_create_channel(void)
1df4dedd 202{
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203 return ask_sessiond(KERNEL_CREATE_CHANNEL, NULL);
204}
205
206/*
207 * lttng_kernel_start_tracing
208 *
209 * Start kernel tracing.
210 */
211int lttng_kernel_start_tracing(void)
212{
213 return ask_sessiond(KERNEL_START_TRACE, NULL);
214}
215
216/*
217 * lttng_kernel_stop_tracing
218 *
219 * Stop kernel tracing.
220 */
221int lttng_kernel_stop_tracing(void)
222{
223 return ask_sessiond(KERNEL_STOP_TRACE, NULL);
224}
225
226/*
227 * END KERNEL CONTROL
228 */
229
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230/*
231 * lttng_get_readable_code
232 *
233 * Return a human readable string of code
234 */
235const char *lttng_get_readable_code(int code)
236{
237 if (code > -LTTCOMM_OK) {
238 return "Ended with errors";
239 }
240
241 return lttcomm_get_readable_code(code);
242}
243
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244/*
245 * lttng_ust_start_trace
246 *
247 * Request a trace start for pid.
248 */
249int lttng_ust_start_trace(pid_t pid)
250{
251 int ret;
252
253 lsm.pid = pid;
254 ret = ask_sessiond(UST_START_TRACE, NULL);
255
256 return ret;
257}
258
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259/*
260 * lttng_ust_stop_trace
261 *
262 * Request a trace stop for pid.
263 */
264int lttng_ust_stop_trace(pid_t pid)
265{
266 int ret;
267
268 lsm.pid = pid;
269 ret = ask_sessiond(UST_STOP_TRACE, NULL);
270
271 return ret;
272}
273
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274/*
275 * lttng_ust_create_trace
276 *
277 * Request a trace creation for pid.
278 */
279int lttng_ust_create_trace(pid_t pid)
280{
281 int ret;
282
283 lsm.pid = pid;
284 ret = ask_sessiond(UST_CREATE_TRACE, NULL);
285
286 return ret;
287}
288
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289/*
290 * lttng_ust_list_apps
291 *
292 * Ask the session daemon for all UST traceable
293 * applications.
294 *
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295 * Return the number of pids.
296 * On error, return negative value.
fac6795d 297 */
ca95a216 298int lttng_ust_list_apps(pid_t **pids)
fac6795d 299{
ca95a216 300 int ret;
fac6795d 301
ca95a216 302 ret = ask_sessiond(UST_LIST_APPS, (void**) pids);
fac6795d 303 if (ret < 0) {
ca95a216 304 return ret;
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305 }
306
ca95a216 307 return ret / sizeof(pid_t);
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308}
309
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310/*
311 * lttng_list_traces
312 *
313 * Ask the session daemon for all traces (kernel and ust)
314 * for the session identified by uuid.
315 *
316 * Return the number of traces.
317 */
318int lttng_list_traces(uuid_t *uuid, struct lttng_trace **traces)
319{
320 int ret;
321
5461b305 322 uuid_copy(lsm.session_uuid, *uuid);
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323
324 ret = ask_sessiond(LTTNG_LIST_TRACES, (void **) traces);
325 if (ret < 0) {
326 return ret;
327 }
328
329 return ret / sizeof(struct lttng_trace);
330}
331
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332/*
333 * lttng_create_session
334 *
894be886 335 * Create a brand new session using name.
aaf97519 336 */
894be886 337int lttng_create_session(char *name)
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338{
339 int ret;
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340
341 strncpy(lsm.session_name, name, sizeof(lsm.session_name));
8028d920 342 lsm.session_name[sizeof(lsm.session_name) - 1] = '\0';
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343
344 ret = ask_sessiond(LTTNG_CREATE_SESSION, NULL);
345 if (ret < 0) {
346 goto end;
347 }
348
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349end:
350 return ret;
351}
352
353/*
354 * lttng_destroy_session
355 *
356 * Destroy session using name.
357 */
358int lttng_destroy_session(uuid_t *uuid)
359{
360 int ret;
361
5461b305 362 uuid_copy(lsm.session_uuid, *uuid);
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363
364 ret = ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
365 if (ret < 0) {
366 goto end;
367 }
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368
369end:
370 return ret;
371}
372
57167058
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373/*
374 * lttng_list_sessions
375 *
376 * Ask the session daemon for all available sessions.
377 *
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378 * Return number of session.
379 * On error, return negative value.
57167058 380 */
ca95a216 381int lttng_list_sessions(struct lttng_session **sessions)
57167058 382{
ca95a216 383 int ret;
57167058 384
ca95a216 385 ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
57167058 386 if (ret < 0) {
ca95a216 387 return ret;
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388 }
389
ca95a216 390 return ret / sizeof(struct lttng_session);
57167058
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391}
392
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393/*
394 * lttng_connect_sessiond
395 *
396 * Connect to the LTTng session daemon.
397 * On success, return 0
398 * On error, return a negative value
399 */
400int lttng_connect_sessiond(void)
401{
402 int ret;
403
404 ret = set_session_daemon_path();
405 if (ret < 0) {
406 return ret;
407 }
408
409 /* Connect to the sesssion daemon */
410 ret = lttcomm_connect_unix_sock(sessiond_sock_path);
411 if (ret < 0) {
412 return ret;
413 }
414
415 sessiond_socket = ret;
416 connected = 1;
417
418 return 0;
419}
420
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421/*
422 * lttng_disconnect_sessiond
423 *
424 * Clean disconnect the session daemon.
425 */
426int lttng_disconnect_sessiond(void)
427{
428 int ret = 0;
429
430 if (connected) {
431 ret = lttcomm_close_unix_sock(sessiond_socket);
432 sessiond_socket = 0;
433 connected = 0;
434 }
435
436 return ret;
437}
438
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439/*
440 * lttng_set_current_session_uuid
441 *
442 * Set the session uuid for current lsm.
443 */
96243366 444void lttng_set_current_session_uuid(uuid_t *uuid)
e8be5f4f 445{
5461b305 446 uuid_copy(lsm.session_uuid, *uuid);
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447}
448
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449/*
450 * lttng_set_tracing_group
451 *
452 * Set tracing group variable with name. This function
453 * allocate memory pointed by tracing_group.
454 */
455int lttng_set_tracing_group(const char *name)
456{
457 if (asprintf(&tracing_group, "%s", name) < 0) {
458 return -ENOMEM;
459 }
460
461 return 0;
462}
463
464/*
465 * lttng_check_session_daemon
466 *
467 * Return 0 if a sesssion daemon is available
468 * else return -1
469 */
470int lttng_check_session_daemon(void)
471{
472 int ret;
473
474 ret = set_session_daemon_path();
475 if (ret < 0) {
476 return ret;
477 }
478
479 /* If socket exist, we consider the daemon started */
480 ret = access(sessiond_sock_path, F_OK);
481 if (ret < 0) {
482 return ret;
483 }
484
485 return 0;
486}
487
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488/*
489 * set_session_daemon_path
490 *
491 * Set sessiond socket path by putting it in
492 * the global sessiond_sock_path variable.
493 */
494static int set_session_daemon_path(void)
495{
496 int ret;
497
498 /* Are we in the tracing group ? */
499 ret = check_tracing_group(tracing_group);
847177cd 500 if (ret < 0 && getuid() != 0) {
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501 if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
502 getenv("HOME")) < 0) {
503 return -ENOMEM;
504 }
505 } else {
506 strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
507 sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
508 }
509
510 return 0;
511}
512
513/*
514 * check_tracing_group
515 *
516 * Check if the specified group name exist.
517 * If yes, 0, else -1
518 */
519static int check_tracing_group(const char *grp_name)
520{
521 struct group *grp_tracing; /* no free(). See getgrnam(3) */
522 gid_t *grp_list;
523 int grp_list_size, grp_id, i;
524 int ret = -1;
525
526 /* Get GID of group 'tracing' */
527 grp_tracing = getgrnam(grp_name);
528 if (grp_tracing == NULL) {
529 /* NULL means not found also. getgrnam(3) */
530 if (errno != 0) {
531 perror("getgrnam");
532 }
533 goto end;
534 }
535
536 /* Get number of supplementary group IDs */
537 grp_list_size = getgroups(0, NULL);
538 if (grp_list_size < 0) {
539 perror("getgroups");
540 goto end;
541 }
542
543 /* Alloc group list of the right size */
544 grp_list = malloc(grp_list_size * sizeof(gid_t));
545 grp_id = getgroups(grp_list_size, grp_list);
546 if (grp_id < -1) {
547 perror("getgroups");
548 goto free_list;
549 }
550
551 for (i = 0; i < grp_list_size; i++) {
552 if (grp_list[i] == grp_tracing->gr_gid) {
553 ret = 0;
554 break;
555 }
556 }
557
558free_list:
559 free(grp_list);
560
561end:
562 return ret;
563}
564
565/*
566 * lib constructor
567 */
568static void __attribute__((constructor)) init()
569{
570 /* Set default session group */
571 lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
572}
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