b64ace2e6d80de0ce085791f698604e53f8eb523
[lttng-tools.git] / liblttngctl / lttngctl.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 <grp.h>
25 #include <errno.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30
31 #include <lttng-sessiond-comm.h>
32 #include <lttng-share.h>
33 #include <lttng/lttng.h>
34 #include <lttngerr.h>
35
36 /* Socket to session daemon for communication */
37 static int sessiond_socket;
38 static char sessiond_sock_path[PATH_MAX];
39
40 /* Variables */
41 static char *tracing_group;
42 static int connected;
43
44 /*
45 * Copy string from src to dst and enforce null terminated byte.
46 */
47 static void copy_string(char *dst, const char *src, size_t len)
48 {
49 if (src && dst) {
50 strncpy(dst, src, len);
51 /* Enforce the NULL terminated byte */
52 dst[len - 1] = '\0';
53 } else if (dst) {
54 dst[0] = '\0';
55 }
56 }
57
58 /*
59 * Copy domain to lttcomm_session_msg domain.
60 *
61 * If domain is unknown, default domain will be the kernel.
62 */
63 static void copy_lttng_domain(struct lttng_domain *dst, struct lttng_domain *src)
64 {
65 if (src && dst) {
66 switch (src->type) {
67 case LTTNG_DOMAIN_KERNEL:
68 case LTTNG_DOMAIN_UST:
69 case LTTNG_DOMAIN_UST_EXEC_NAME:
70 case LTTNG_DOMAIN_UST_PID:
71 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
72 memcpy(dst, src, sizeof(struct lttng_domain));
73 break;
74 default:
75 dst->type = LTTNG_DOMAIN_KERNEL;
76 break;
77 }
78 }
79 }
80
81 /*
82 * Send lttcomm_session_msg to the session daemon.
83 *
84 * On success, return 0
85 * On error, return error code
86 */
87 static int send_session_msg(struct lttcomm_session_msg *lsm)
88 {
89 int ret;
90
91 if (!connected) {
92 ret = -ENOTCONN;
93 goto end;
94 }
95
96 ret = lttcomm_send_unix_sock(sessiond_socket, lsm,
97 sizeof(struct lttcomm_session_msg));
98
99 end:
100 return ret;
101 }
102
103 /*
104 * Receive data from the sessiond socket.
105 *
106 * On success, return 0
107 * On error, return recv() error code
108 */
109 static int recv_data_sessiond(void *buf, size_t len)
110 {
111 int ret;
112
113 if (!connected) {
114 ret = -ENOTCONN;
115 goto end;
116 }
117
118 ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
119
120 end:
121 return ret;
122 }
123
124 /*
125 * Check if the specified group name exist.
126 *
127 * If yes return 1, else return -1.
128 */
129 static int check_tracing_group(const char *grp_name)
130 {
131 struct group *grp_tracing; /* no free(). See getgrnam(3) */
132 gid_t *grp_list;
133 int grp_list_size, grp_id, i;
134 int ret = -1;
135
136 /* Get GID of group 'tracing' */
137 grp_tracing = getgrnam(grp_name);
138 if (grp_tracing == NULL) {
139 /* NULL means not found also. getgrnam(3) */
140 if (errno != 0) {
141 perror("getgrnam");
142 }
143 goto end;
144 }
145
146 /* Get number of supplementary group IDs */
147 grp_list_size = getgroups(0, NULL);
148 if (grp_list_size < 0) {
149 perror("getgroups");
150 goto end;
151 }
152
153 /* Alloc group list of the right size */
154 grp_list = malloc(grp_list_size * sizeof(gid_t));
155 grp_id = getgroups(grp_list_size, grp_list);
156 if (grp_id < -1) {
157 perror("getgroups");
158 goto free_list;
159 }
160
161 for (i = 0; i < grp_list_size; i++) {
162 if (grp_list[i] == grp_tracing->gr_gid) {
163 ret = 1;
164 break;
165 }
166 }
167
168 free_list:
169 free(grp_list);
170
171 end:
172 return ret;
173 }
174
175 /*
176 * Try connect to session daemon with sock_path.
177 *
178 * Return 0 on success, else -1
179 */
180 static int try_connect_sessiond(const char *sock_path)
181 {
182 int ret;
183
184 /* If socket exist, we check if the daemon listens for connect. */
185 ret = access(sock_path, F_OK);
186 if (ret < 0) {
187 /* Not alive */
188 return -1;
189 }
190
191 ret = lttcomm_connect_unix_sock(sock_path);
192 if (ret < 0) {
193 /* Not alive */
194 return -1;
195 }
196
197 ret = lttcomm_close_unix_sock(ret);
198 if (ret < 0) {
199 perror("lttcomm_close_unix_sock");
200 }
201
202 return 0;
203 }
204
205 /*
206 * Set sessiond socket path by putting it in the global sessiond_sock_path
207 * variable.
208 */
209 static int set_session_daemon_path(void)
210 {
211 int ret;
212 int in_tgroup = 0; /* In tracing group */
213 uid_t uid;
214
215 uid = getuid();
216
217 if (uid != 0) {
218 /* Are we in the tracing group ? */
219 in_tgroup = check_tracing_group(tracing_group);
220 }
221
222 if (uid == 0) {
223 /* Root */
224 copy_string(sessiond_sock_path,
225 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
226 sizeof(sessiond_sock_path));
227 } else if (in_tgroup) {
228 /* Tracing group */
229 copy_string(sessiond_sock_path,
230 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
231 sizeof(sessiond_sock_path));
232
233 ret = try_connect_sessiond(sessiond_sock_path);
234 if (ret < 0) {
235 /* Global session daemon not available */
236 if (snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
237 DEFAULT_HOME_CLIENT_UNIX_SOCK,
238 getenv("HOME")) < 0) {
239 return -ENOMEM;
240 }
241 }
242 } else {
243 /* Not in tracing group and not root, default */
244 if (snprintf(sessiond_sock_path, PATH_MAX,
245 DEFAULT_HOME_CLIENT_UNIX_SOCK,
246 getenv("HOME")) < 0) {
247 return -ENOMEM;
248 }
249 }
250
251 return 0;
252 }
253
254 /*
255 * Connect to the LTTng session daemon.
256 *
257 * On success, return 0. On error, return -1.
258 */
259 static int connect_sessiond(void)
260 {
261 int ret;
262
263 ret = set_session_daemon_path();
264 if (ret < 0) {
265 return ret;
266 }
267
268 /* Connect to the sesssion daemon */
269 ret = lttcomm_connect_unix_sock(sessiond_sock_path);
270 if (ret < 0) {
271 return ret;
272 }
273
274 sessiond_socket = ret;
275 connected = 1;
276
277 return 0;
278 }
279
280 /*
281 * Clean disconnect the session daemon.
282 */
283 static int disconnect_sessiond(void)
284 {
285 int ret = 0;
286
287 if (connected) {
288 ret = lttcomm_close_unix_sock(sessiond_socket);
289 sessiond_socket = 0;
290 connected = 0;
291 }
292
293 return ret;
294 }
295
296 /*
297 * Ask the session daemon a specific command and put the data into buf.
298 *
299 * Return size of data (only payload, not header).
300 */
301 static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
302 {
303 int ret;
304 size_t size;
305 void *data = NULL;
306 struct lttcomm_lttng_msg llm;
307
308 ret = connect_sessiond();
309 if (ret < 0) {
310 goto end;
311 }
312
313 /* Send command to session daemon */
314 ret = send_session_msg(lsm);
315 if (ret < 0) {
316 goto end;
317 }
318
319 /* Get header from data transmission */
320 ret = recv_data_sessiond(&llm, sizeof(llm));
321 if (ret < 0) {
322 goto end;
323 }
324
325 /* Check error code if OK */
326 if (llm.ret_code != LTTCOMM_OK) {
327 ret = -llm.ret_code;
328 goto end;
329 }
330
331 size = llm.data_size;
332 if (size == 0) {
333 ret = 0;
334 goto end;
335 }
336
337 data = (void*) malloc(size);
338
339 /* Get payload data */
340 ret = recv_data_sessiond(data, size);
341 if (ret < 0) {
342 free(data);
343 goto end;
344 }
345
346 /*
347 * Extra protection not to dereference a NULL pointer. If buf is NULL at
348 * this point, an error is returned and data is freed.
349 */
350 if (buf == NULL) {
351 ret = -1;
352 free(data);
353 goto end;
354 }
355
356 *buf = data;
357 ret = size;
358
359 end:
360 disconnect_sessiond();
361 return ret;
362 }
363
364 /*
365 * Create lttng handle and return pointer.
366 */
367 struct lttng_handle *lttng_create_handle(const char *session_name,
368 struct lttng_domain *domain)
369 {
370 struct lttng_handle *handle;
371
372 handle = malloc(sizeof(struct lttng_handle));
373 if (handle == NULL) {
374 perror("malloc handle");
375 goto end;
376 }
377
378 /* Copy session name */
379 copy_string(handle->session_name, session_name,
380 sizeof(handle->session_name));
381
382 /* Copy lttng domain */
383 copy_lttng_domain(&handle->domain, domain);
384
385 end:
386 return handle;
387 }
388
389 /*
390 * Destroy handle by free(3) the pointer.
391 */
392 void lttng_destroy_handle(struct lttng_handle *handle)
393 {
394 if (handle) {
395 free(handle);
396 }
397 }
398
399 /*
400 * Register an outside consumer.
401 */
402 int lttng_register_consumer(struct lttng_handle *handle,
403 const char *socket_path)
404 {
405 struct lttcomm_session_msg lsm;
406
407 lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
408 copy_string(lsm.session.name, handle->session_name,
409 sizeof(lsm.session.name));
410 copy_lttng_domain(&lsm.domain, &handle->domain);
411
412 copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
413
414 return ask_sessiond(&lsm, NULL);
415 }
416
417 /*
418 * Start tracing for all trace of the session.
419 */
420 int lttng_start_tracing(struct lttng_handle *handle)
421 {
422 struct lttcomm_session_msg lsm;
423
424 if (!handle) {
425 return -1;
426 }
427
428 lsm.cmd_type = LTTNG_START_TRACE;
429 copy_string(lsm.session.name, handle->session_name,
430 sizeof(lsm.session.name));
431
432 return ask_sessiond(&lsm, NULL);
433 }
434
435 /*
436 * Stop tracing for all trace of the session.
437 */
438 int lttng_stop_tracing(struct lttng_handle *handle)
439 {
440 struct lttcomm_session_msg lsm;
441
442 lsm.cmd_type = LTTNG_STOP_TRACE;
443 copy_string(lsm.session.name, handle->session_name,
444 sizeof(lsm.session.name));
445
446 return ask_sessiond(&lsm, NULL);
447 }
448
449 /*
450 * Add context to event or/and channel.
451 */
452 int lttng_add_context(struct lttng_handle *handle,
453 struct lttng_event_context *ctx, const char *event_name,
454 const char *channel_name)
455 {
456 struct lttcomm_session_msg lsm;
457
458 if (!handle) {
459 return -1;
460 }
461
462 lsm.cmd_type = LTTNG_ADD_CONTEXT;
463
464 /* Copy channel name */
465 copy_string(lsm.u.context.channel_name, channel_name,
466 sizeof(lsm.u.context.channel_name));
467 /* Copy event name */
468 copy_string(lsm.u.context.event_name, event_name,
469 sizeof(lsm.u.context.event_name));
470
471 copy_lttng_domain(&lsm.domain, &handle->domain);
472
473 if (ctx) {
474 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
475 }
476
477 copy_string(lsm.session.name, handle->session_name,
478 sizeof(lsm.session.name));
479
480 return ask_sessiond(&lsm, NULL);
481 }
482
483 /*
484 * Enable event
485 */
486 int lttng_enable_event(struct lttng_handle *handle,
487 struct lttng_event *ev, const char *channel_name)
488 {
489 struct lttcomm_session_msg lsm;
490
491 if (!handle) {
492 return -1;
493 }
494
495 if (channel_name == NULL) {
496 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
497 sizeof(lsm.u.enable.channel_name));
498 } else {
499 copy_string(lsm.u.enable.channel_name, channel_name,
500 sizeof(lsm.u.enable.channel_name));
501 }
502
503 copy_lttng_domain(&lsm.domain, &handle->domain);
504
505 if (ev) {
506 lsm.cmd_type = LTTNG_ENABLE_EVENT;
507 memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
508 } else {
509 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
510 }
511
512 copy_string(lsm.session.name, handle->session_name,
513 sizeof(lsm.session.name));
514
515 return ask_sessiond(&lsm, NULL);
516 }
517
518 /*
519 * Disable event of a channel and domain.
520 */
521 int lttng_disable_event(struct lttng_handle *handle, const char *name,
522 const char *channel_name)
523 {
524 struct lttcomm_session_msg lsm;
525
526 if (!handle) {
527 return -1;
528 }
529
530 if (channel_name) {
531 copy_string(lsm.u.disable.channel_name, channel_name,
532 sizeof(lsm.u.disable.channel_name));
533 } else {
534 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
535 sizeof(lsm.u.disable.channel_name));
536 }
537
538 copy_lttng_domain(&lsm.domain, &handle->domain);
539
540 if (name == NULL) {
541 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
542 lsm.cmd_type = LTTNG_DISABLE_EVENT;
543 } else {
544 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
545 }
546
547 copy_string(lsm.session.name, handle->session_name,
548 sizeof(lsm.session.name));
549
550 return ask_sessiond(&lsm, NULL);
551 }
552
553 /*
554 * Enable channel per domain
555 */
556 int lttng_enable_channel(struct lttng_handle *handle,
557 struct lttng_channel *chan)
558 {
559 struct lttcomm_session_msg lsm;
560
561 if (!handle) {
562 return -1;
563 }
564
565 if (chan) {
566 memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
567 }
568
569 lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
570
571 copy_lttng_domain(&lsm.domain, &handle->domain);
572
573 copy_string(lsm.session.name, handle->session_name,
574 sizeof(lsm.session.name));
575
576 return ask_sessiond(&lsm, NULL);
577 }
578
579 /*
580 * All tracing will be stopped for registered events of the channel.
581 */
582 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
583 {
584 struct lttcomm_session_msg lsm;
585
586 if (!handle) {
587 return -1;
588 }
589
590 if (name) {
591 copy_string(lsm.u.disable.channel_name, name,
592 sizeof(lsm.u.disable.channel_name));
593 }
594
595 lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
596
597 copy_lttng_domain(&lsm.domain, &handle->domain);
598
599 copy_string(lsm.session.name, handle->session_name,
600 sizeof(lsm.session.name));
601
602 return ask_sessiond(&lsm, NULL);
603 }
604
605 /*
606 * List all available tracepoints of domain.
607 *
608 * Return the size (bytes) of the list and set the events array.
609 * On error, return negative value.
610 */
611 int lttng_list_tracepoints(struct lttng_handle *handle,
612 struct lttng_event **events)
613 {
614 int ret;
615 struct lttcomm_session_msg lsm;
616
617 if (!handle) {
618 return -1;
619 }
620
621 lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
622 copy_lttng_domain(&lsm.domain, &handle->domain);
623
624 ret = ask_sessiond(&lsm, (void **) events);
625 if (ret < 0) {
626 return ret;
627 }
628
629 return ret / sizeof(struct lttng_event);
630 }
631
632 /*
633 * Return a human readable string of code
634 */
635 const char *lttng_get_readable_code(int code)
636 {
637 if (code > -LTTCOMM_OK) {
638 return "Ended with errors";
639 }
640
641 return lttcomm_get_readable_code(code);
642 }
643
644 /*
645 * Create a brand new session using name.
646 */
647 int lttng_create_session(const char *name, const char *path)
648 {
649 struct lttcomm_session_msg lsm;
650
651 lsm.cmd_type = LTTNG_CREATE_SESSION;
652 copy_string(lsm.session.name, name, sizeof(lsm.session.name));
653 copy_string(lsm.session.path, path, sizeof(lsm.session.path));
654
655 return ask_sessiond(&lsm, NULL);
656 }
657
658 /*
659 * Destroy session using name.
660 */
661 int lttng_destroy_session(struct lttng_handle *handle)
662 {
663 struct lttcomm_session_msg lsm;
664
665 if (!handle) {
666 return -1;
667 }
668
669 lsm.cmd_type = LTTNG_DESTROY_SESSION;
670 copy_string(lsm.session.name, handle->session_name,
671 sizeof(lsm.session.name));
672
673 return ask_sessiond(&lsm, NULL);
674 }
675
676 /*
677 * Ask the session daemon for all available sessions.
678 *
679 * Return number of session.
680 * On error, return negative value.
681 */
682 int lttng_list_sessions(struct lttng_session **sessions)
683 {
684 int ret;
685 struct lttcomm_session_msg lsm;
686
687 lsm.cmd_type = LTTNG_LIST_SESSIONS;
688 ret = ask_sessiond(&lsm, (void**) sessions);
689 if (ret < 0) {
690 return ret;
691 }
692
693 return ret / sizeof(struct lttng_session);
694 }
695
696 /*
697 * List domain of a session.
698 */
699 int lttng_list_domains(struct lttng_handle *handle,
700 struct lttng_domain **domains)
701 {
702 int ret;
703 struct lttcomm_session_msg lsm;
704
705 if (!handle) {
706 return -1;
707 }
708
709 lsm.cmd_type = LTTNG_LIST_DOMAINS;
710
711 copy_string(lsm.session.name, handle->session_name,
712 sizeof(lsm.session.name));
713
714 ret = ask_sessiond(&lsm, (void**) domains);
715 if (ret < 0) {
716 return ret;
717 }
718
719 return ret / sizeof(struct lttng_domain);
720 }
721
722 /*
723 * List channels of a session
724 */
725 int lttng_list_channels(struct lttng_handle *handle,
726 struct lttng_channel **channels)
727 {
728 int ret;
729 struct lttcomm_session_msg lsm;
730
731 if (!handle) {
732 return -1;
733 }
734
735 lsm.cmd_type = LTTNG_LIST_CHANNELS;
736 copy_string(lsm.session.name, handle->session_name,
737 sizeof(lsm.session.name));
738
739 copy_lttng_domain(&lsm.domain, &handle->domain);
740
741 ret = ask_sessiond(&lsm, (void**) channels);
742 if (ret < 0) {
743 return ret;
744 }
745
746 return ret / sizeof(struct lttng_channel);
747 }
748
749 /*
750 * List events of a session channel.
751 */
752 int lttng_list_events(struct lttng_handle *handle,
753 const char *channel_name, struct lttng_event **events)
754 {
755 int ret;
756 struct lttcomm_session_msg lsm;
757
758 if (!handle) {
759 return -1;
760 }
761
762 lsm.cmd_type = LTTNG_LIST_EVENTS;
763 copy_string(lsm.session.name, handle->session_name,
764 sizeof(lsm.session.name));
765 copy_string(lsm.u.list.channel_name, channel_name,
766 sizeof(lsm.u.list.channel_name));
767
768 copy_lttng_domain(&lsm.domain, &handle->domain);
769
770 ret = ask_sessiond(&lsm, (void**) events);
771 if (ret < 0) {
772 return ret;
773 }
774
775 return ret / sizeof(struct lttng_event);
776 }
777
778 /*
779 * lttng_set_tracing_group
780 *
781 * Set tracing group variable with name. This function
782 * allocate memory pointed by tracing_group.
783 */
784 int lttng_set_tracing_group(const char *name)
785 {
786 if (asprintf(&tracing_group, "%s", name) < 0) {
787 return -ENOMEM;
788 }
789
790 return 0;
791 }
792
793 /*
794 * lttng_calibrate
795 */
796 int lttng_calibrate(struct lttng_handle *handle,
797 struct lttng_calibrate *calibrate)
798 {
799 struct lttcomm_session_msg lsm;
800
801 if (!handle) {
802 return -1;
803 }
804
805 lsm.cmd_type = LTTNG_CALIBRATE;
806 copy_lttng_domain(&lsm.domain, &handle->domain);
807
808 memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
809
810 return ask_sessiond(&lsm, NULL);
811 }
812
813 /*
814 * Check if session daemon is alive.
815 *
816 * Return 1 if alive or 0 if not.
817 * On error return -1
818 */
819 int lttng_session_daemon_alive(void)
820 {
821 int ret;
822
823 ret = set_session_daemon_path();
824 if (ret < 0) {
825 /* Error */
826 return ret;
827 }
828
829 if (strlen(sessiond_sock_path) == 0) {
830 /* No socket path set. Weird error */
831 return -1;
832 }
833
834 ret = try_connect_sessiond(sessiond_sock_path);
835 if (ret < 0) {
836 /* Not alive */
837 return 0;
838 }
839
840 /* Is alive */
841 return 1;
842 }
843
844 /*
845 * lib constructor
846 */
847 static void __attribute__((constructor)) init()
848 {
849 /* Set default session group */
850 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
851 }
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