Change list kernel events to list tracepoints
[lttng-tools.git] / liblttngctl / liblttngctl.c
1 /*
2 * liblttngctl.c
3 *
4 * Linux Trace Toolkit Control Library
5 *
6 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
7 *
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,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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
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
31 #include <lttng/lttng.h>
32
33 #include "liblttsessiondcomm.h"
34 #include "lttngerr.h"
35 #include "lttng-share.h"
36
37 /* Socket to session daemon for communication */
38 static int sessiond_socket;
39 static char sessiond_sock_path[PATH_MAX];
40
41 /* Communication structure to ltt-sessiond */
42 static struct lttcomm_session_msg lsm;
43 static struct lttcomm_lttng_msg llm;
44
45 /* Variables */
46 static char *tracing_group;
47 static int connected;
48
49 /*
50 * send_data_sessiond
51 *
52 * Send lttcomm_session_msg to the session daemon.
53 *
54 * On success, return 0
55 * On error, return error code
56 */
57 static int send_data_sessiond(void)
58 {
59 int ret;
60
61 if (!connected) {
62 ret = -ENOTCONN;
63 goto end;
64 }
65
66 ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
67
68 end:
69 return ret;
70 }
71
72 /*
73 * recv_data_sessiond
74 *
75 * Receive data from the sessiond socket.
76 *
77 * On success, return 0
78 * On error, return recv() error code
79 */
80 static int recv_data_sessiond(void *buf, size_t len)
81 {
82 int ret;
83
84 if (!connected) {
85 ret = -ENOTCONN;
86 goto end;
87 }
88
89 ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
90
91 end:
92 return ret;
93 }
94
95 /*
96 * Check if the specified group name exist.
97 *
98 * If yes return 0, else return -1.
99 */
100 static 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
139 free_list:
140 free(grp_list);
141
142 end:
143 return ret;
144 }
145
146 /*
147 * Set sessiond socket path by putting it in the global sessiond_sock_path
148 * variable.
149 */
150 static 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
169 /*
170 * Connect to the LTTng session daemon.
171 *
172 * On success, return 0. On error, return -1.
173 */
174 static 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 */
198 static 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
211 /*
212 * Reset the session message structure.
213 */
214 static void reset_session_msg(void)
215 {
216 memset(&lsm, 0, sizeof(struct lttcomm_session_msg));
217 }
218
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 */
226 static 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) {
259 ret = 0;
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
275 end:
276 disconnect_sessiond();
277 reset_session_msg();
278 return ret;
279 }
280
281 /*
282 * Copy domain to lttcomm_session_msg domain.
283 *
284 * Return -1 if the domain is unkown.
285 */
286 static 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
301 /*
302 * Start tracing for all trace of the session.
303 */
304 int lttng_start_tracing(const char *session_name)
305 {
306 strncpy(lsm.session_name, session_name, NAME_MAX);
307 return ask_sessiond(LTTNG_START_TRACE, NULL);
308 }
309
310 /*
311 * Stop tracing for all trace of the session.
312 */
313 int lttng_stop_tracing(const char *session_name)
314 {
315 strncpy(lsm.session_name, session_name, NAME_MAX);
316 return ask_sessiond(LTTNG_STOP_TRACE, NULL);
317 }
318
319 /*
320 * lttng_add_context
321 */
322 int lttng_add_context(struct lttng_domain *domain,
323 struct lttng_event_context *ctx, const char *event_name,
324 const char *channel_name)
325 {
326 int ret;
327
328 if (channel_name != NULL) {
329 strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX);
330 }
331
332 if (event_name != NULL) {
333 strncpy(lsm.u.context.event_name, event_name, NAME_MAX);
334 }
335
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;
351 }
352
353 /*
354 * lttng_enable_event
355 */
356 int lttng_enable_event(struct lttng_domain *domain,
357 struct lttng_event *ev, const char *channel_name)
358 {
359 int ret;
360
361 if (channel_name == NULL) {
362 strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
363 } else {
364 strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX);
365 }
366
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 };
383
384 return ret;
385 }
386
387 /*
388 * Disable an event in the kernel tracer.
389 */
390 int lttng_disable_event(struct lttng_domain *domain, const char *name,
391 const char *channel_name)
392 {
393 int ret;
394
395 if (channel_name == NULL) {
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
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 };
417
418 return ret;
419 }
420
421 /*
422 * Enable recording for a channel for the kernel tracer.
423 */
424 int lttng_enable_channel(struct lttng_domain *domain,
425 struct lttng_channel *chan)
426 {
427 int ret;
428
429 memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
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;
444 }
445
446 /*
447 * Disable recording for the channel for the kernel tracer.
448 */
449 int lttng_disable_channel(struct lttng_domain *domain, const char *name)
450 {
451 int ret;
452
453 strncpy(lsm.u.disable.channel_name, name, NAME_MAX);
454
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 };
466
467 return ret;
468 }
469
470 /*
471 * List all available tracepoints of domain.
472 *
473 * Return the size (bytes) of the list and set the events array.
474 * On error, return negative value.
475 */
476 int lttng_list_tracepoints(struct lttng_domain *domain,
477 struct lttng_event **events)
478 {
479 int ret;
480
481 ret = copy_lttng_domain(domain);
482 if (ret < 0) {
483 return -LTTCOMM_UNKNOWN_DOMAIN;
484 }
485
486 switch (domain->type) {
487 case LTTNG_DOMAIN_KERNEL:
488 ret = ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) events);
489 break;
490 case LTTNG_DOMAIN_UST:
491 ret = LTTCOMM_NOT_IMPLEMENTED;
492 break;
493 default:
494 ret = LTTCOMM_UNKNOWN_DOMAIN;
495 break;
496 };
497
498 return ret / sizeof(struct lttng_event);
499 }
500
501 /*
502 * Return a human readable string of code
503 */
504 const char *lttng_get_readable_code(int code)
505 {
506 if (code > -LTTCOMM_OK) {
507 return "Ended with errors";
508 }
509
510 return lttcomm_get_readable_code(code);
511 }
512
513 /*
514 * Create a brand new session using name.
515 */
516 int lttng_create_session(const char *name, const char *path)
517 {
518 strncpy(lsm.session_name, name, NAME_MAX);
519 strncpy(lsm.path, path, PATH_MAX);
520 return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
521 }
522
523 /*
524 * Destroy session using name.
525 */
526 int lttng_destroy_session(const char *name)
527 {
528 strncpy(lsm.session_name, name, NAME_MAX);
529 return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
530 }
531
532 /*
533 * Ask the session daemon for all available sessions.
534 *
535 * Return number of session.
536 * On error, return negative value.
537 */
538 int lttng_list_sessions(struct lttng_session **sessions)
539 {
540 int ret;
541
542 ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
543 if (ret < 0) {
544 return ret;
545 }
546
547 return ret / sizeof(struct lttng_session);
548 }
549
550 /*
551 * List domain of a session.
552 */
553 int lttng_list_domains(const char *session_name, struct lttng_domain **domains)
554 {
555 int ret;
556
557 strncpy(lsm.session_name, session_name, NAME_MAX);
558 ret = ask_sessiond(LTTNG_LIST_DOMAINS, (void**) domains);
559 if (ret < 0) {
560 return ret;
561 }
562
563 return ret / sizeof(struct lttng_domain);
564 }
565
566 /*
567 * List channels of a session
568 */
569 int lttng_list_channels(struct lttng_domain *domain,
570 const char *session_name, struct lttng_channel **channels)
571 {
572 int ret;
573
574 strncpy(lsm.session_name, session_name, NAME_MAX);
575 ret = copy_lttng_domain(domain);
576 if (ret < 0) {
577 return -LTTCOMM_UNKNOWN_DOMAIN;
578 }
579
580 ret = ask_sessiond(LTTNG_LIST_CHANNELS, (void**) channels);
581 if (ret < 0) {
582 return ret;
583 }
584
585 return ret / sizeof(struct lttng_channel);
586 }
587
588 /*
589 * List events of a session channel.
590 */
591 int lttng_list_events(struct lttng_domain *domain,
592 const char *session_name, const char *channel_name,
593 struct lttng_event **events)
594 {
595 int ret;
596
597 strncpy(lsm.session_name, session_name, NAME_MAX);
598 strncpy(lsm.u.list.channel_name, channel_name, NAME_MAX);
599 ret = copy_lttng_domain(domain);
600 if (ret < 0) {
601 return -LTTCOMM_UNKNOWN_DOMAIN;
602 }
603
604 ret = ask_sessiond(LTTNG_LIST_EVENTS, (void**) events);
605 if (ret < 0) {
606 return ret;
607 }
608
609 return ret / sizeof(struct lttng_event);
610 }
611
612 /*
613 * Set session name for the current lsm.
614 */
615 void lttng_set_session_name(const char *name)
616 {
617 strncpy(lsm.session_name, name, NAME_MAX);
618 }
619
620 /*
621 * lttng_set_tracing_group
622 *
623 * Set tracing group variable with name. This function
624 * allocate memory pointed by tracing_group.
625 */
626 int lttng_set_tracing_group(const char *name)
627 {
628 if (asprintf(&tracing_group, "%s", name) < 0) {
629 return -ENOMEM;
630 }
631
632 return 0;
633 }
634
635 /*
636 * lttng_check_session_daemon
637 *
638 * Yes, return 1
639 * No, return 0
640 * Error, return negative value
641 */
642 int lttng_session_daemon_alive(void)
643 {
644 int ret;
645
646 ret = set_session_daemon_path();
647 if (ret < 0) {
648 /* Error */
649 return ret;
650 }
651
652 /* If socket exist, we consider the daemon started */
653 ret = access(sessiond_sock_path, F_OK);
654 if (ret < 0) {
655 /* Not alive */
656 return 0;
657 }
658
659 /* Is alive */
660 return 1;
661 }
662
663 /*
664 * lib constructor
665 */
666 static void __attribute__((constructor)) init()
667 {
668 /* Set default session group */
669 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
670 }
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