a1e577b2bb5f7f4bf14d1950c10928719fbc0eae
[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 if (!grp_list) {
156 ret = -1;
157 goto end;
158 }
159 grp_id = getgroups(grp_list_size, grp_list);
160 if (grp_id < -1) {
161 perror("getgroups");
162 goto free_list;
163 }
164
165 for (i = 0; i < grp_list_size; i++) {
166 if (grp_list[i] == grp_tracing->gr_gid) {
167 ret = 1;
168 break;
169 }
170 }
171
172 free_list:
173 free(grp_list);
174
175 end:
176 return ret;
177 }
178
179 /*
180 * Try connect to session daemon with sock_path.
181 *
182 * Return 0 on success, else -1
183 */
184 static int try_connect_sessiond(const char *sock_path)
185 {
186 int ret;
187
188 /* If socket exist, we check if the daemon listens for connect. */
189 ret = access(sock_path, F_OK);
190 if (ret < 0) {
191 /* Not alive */
192 return -1;
193 }
194
195 ret = lttcomm_connect_unix_sock(sock_path);
196 if (ret < 0) {
197 /* Not alive */
198 return -1;
199 }
200
201 ret = lttcomm_close_unix_sock(ret);
202 if (ret < 0) {
203 perror("lttcomm_close_unix_sock");
204 }
205
206 return 0;
207 }
208
209 /*
210 * Set sessiond socket path by putting it in the global sessiond_sock_path
211 * variable.
212 */
213 static int set_session_daemon_path(void)
214 {
215 int ret;
216 int in_tgroup = 0; /* In tracing group */
217 uid_t uid;
218
219 uid = getuid();
220
221 if (uid != 0) {
222 /* Are we in the tracing group ? */
223 in_tgroup = check_tracing_group(tracing_group);
224 }
225
226 if (uid == 0) {
227 /* Root */
228 copy_string(sessiond_sock_path,
229 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
230 sizeof(sessiond_sock_path));
231 } else if (in_tgroup) {
232 /* Tracing group */
233 copy_string(sessiond_sock_path,
234 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
235 sizeof(sessiond_sock_path));
236
237 ret = try_connect_sessiond(sessiond_sock_path);
238 if (ret < 0) {
239 /* Global session daemon not available */
240 if (snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
241 DEFAULT_HOME_CLIENT_UNIX_SOCK,
242 getenv("HOME")) < 0) {
243 return -ENOMEM;
244 }
245 }
246 } else {
247 /* Not in tracing group and not root, default */
248 if (snprintf(sessiond_sock_path, PATH_MAX,
249 DEFAULT_HOME_CLIENT_UNIX_SOCK,
250 getenv("HOME")) < 0) {
251 return -ENOMEM;
252 }
253 }
254
255 return 0;
256 }
257
258 /*
259 * Connect to the LTTng session daemon.
260 *
261 * On success, return 0. On error, return -1.
262 */
263 static int connect_sessiond(void)
264 {
265 int ret;
266
267 ret = set_session_daemon_path();
268 if (ret < 0) {
269 return ret;
270 }
271
272 /* Connect to the sesssion daemon */
273 ret = lttcomm_connect_unix_sock(sessiond_sock_path);
274 if (ret < 0) {
275 return ret;
276 }
277
278 sessiond_socket = ret;
279 connected = 1;
280
281 return 0;
282 }
283
284 /*
285 * Clean disconnect the session daemon.
286 */
287 static int disconnect_sessiond(void)
288 {
289 int ret = 0;
290
291 if (connected) {
292 ret = lttcomm_close_unix_sock(sessiond_socket);
293 sessiond_socket = 0;
294 connected = 0;
295 }
296
297 return ret;
298 }
299
300 /*
301 * Ask the session daemon a specific command and put the data into buf.
302 *
303 * Return size of data (only payload, not header).
304 */
305 static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
306 {
307 int ret;
308 size_t size;
309 void *data = NULL;
310 struct lttcomm_lttng_msg llm;
311
312 ret = connect_sessiond();
313 if (ret < 0) {
314 goto end;
315 }
316
317 /* Send command to session daemon */
318 ret = send_session_msg(lsm);
319 if (ret < 0) {
320 goto end;
321 }
322
323 /* Get header from data transmission */
324 ret = recv_data_sessiond(&llm, sizeof(llm));
325 if (ret < 0) {
326 goto end;
327 }
328
329 /* Check error code if OK */
330 if (llm.ret_code != LTTCOMM_OK) {
331 ret = -llm.ret_code;
332 goto end;
333 }
334
335 size = llm.data_size;
336 if (size == 0) {
337 /* If client free with size 0 */
338 *buf = NULL;
339 ret = 0;
340 goto end;
341 }
342
343 data = (void*) malloc(size);
344
345 /* Get payload data */
346 ret = recv_data_sessiond(data, size);
347 if (ret < 0) {
348 free(data);
349 goto end;
350 }
351
352 /*
353 * Extra protection not to dereference a NULL pointer. If buf is NULL at
354 * this point, an error is returned and data is freed.
355 */
356 if (buf == NULL) {
357 ret = -1;
358 free(data);
359 goto end;
360 }
361
362 *buf = data;
363 ret = size;
364
365 end:
366 disconnect_sessiond();
367 return ret;
368 }
369
370 /*
371 * Create lttng handle and return pointer.
372 */
373 struct lttng_handle *lttng_create_handle(const char *session_name,
374 struct lttng_domain *domain)
375 {
376 struct lttng_handle *handle;
377
378 handle = malloc(sizeof(struct lttng_handle));
379 if (handle == NULL) {
380 perror("malloc handle");
381 goto end;
382 }
383
384 /* Copy session name */
385 copy_string(handle->session_name, session_name,
386 sizeof(handle->session_name));
387
388 /* Copy lttng domain */
389 copy_lttng_domain(&handle->domain, domain);
390
391 end:
392 return handle;
393 }
394
395 /*
396 * Destroy handle by free(3) the pointer.
397 */
398 void lttng_destroy_handle(struct lttng_handle *handle)
399 {
400 if (handle) {
401 free(handle);
402 }
403 }
404
405 /*
406 * Register an outside consumer.
407 */
408 int lttng_register_consumer(struct lttng_handle *handle,
409 const char *socket_path)
410 {
411 struct lttcomm_session_msg lsm;
412
413 lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
414 copy_string(lsm.session.name, handle->session_name,
415 sizeof(lsm.session.name));
416 copy_lttng_domain(&lsm.domain, &handle->domain);
417
418 copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
419
420 return ask_sessiond(&lsm, NULL);
421 }
422
423 /*
424 * Start tracing for all trace of the session.
425 */
426 int lttng_start_tracing(struct lttng_handle *handle)
427 {
428 struct lttcomm_session_msg lsm;
429
430 if (!handle) {
431 return -1;
432 }
433
434 lsm.cmd_type = LTTNG_START_TRACE;
435 copy_string(lsm.session.name, handle->session_name,
436 sizeof(lsm.session.name));
437
438 return ask_sessiond(&lsm, NULL);
439 }
440
441 /*
442 * Stop tracing for all trace of the session.
443 */
444 int lttng_stop_tracing(struct lttng_handle *handle)
445 {
446 struct lttcomm_session_msg lsm;
447
448 lsm.cmd_type = LTTNG_STOP_TRACE;
449 copy_string(lsm.session.name, handle->session_name,
450 sizeof(lsm.session.name));
451
452 return ask_sessiond(&lsm, NULL);
453 }
454
455 /*
456 * Add context to event or/and channel.
457 */
458 int lttng_add_context(struct lttng_handle *handle,
459 struct lttng_event_context *ctx, const char *event_name,
460 const char *channel_name)
461 {
462 struct lttcomm_session_msg lsm;
463
464 if (!handle) {
465 return -1;
466 }
467
468 lsm.cmd_type = LTTNG_ADD_CONTEXT;
469
470 /* Copy channel name */
471 copy_string(lsm.u.context.channel_name, channel_name,
472 sizeof(lsm.u.context.channel_name));
473 /* Copy event name */
474 copy_string(lsm.u.context.event_name, event_name,
475 sizeof(lsm.u.context.event_name));
476
477 copy_lttng_domain(&lsm.domain, &handle->domain);
478
479 if (ctx) {
480 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
481 }
482
483 copy_string(lsm.session.name, handle->session_name,
484 sizeof(lsm.session.name));
485
486 return ask_sessiond(&lsm, NULL);
487 }
488
489 /*
490 * Enable event
491 */
492 int lttng_enable_event(struct lttng_handle *handle,
493 struct lttng_event *ev, const char *channel_name)
494 {
495 struct lttcomm_session_msg lsm;
496
497 if (!handle || ev == NULL) {
498 return -1;
499 }
500
501 if (channel_name == NULL) {
502 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
503 sizeof(lsm.u.enable.channel_name));
504 } else {
505 copy_string(lsm.u.enable.channel_name, channel_name,
506 sizeof(lsm.u.enable.channel_name));
507 }
508
509 copy_lttng_domain(&lsm.domain, &handle->domain);
510
511 if (ev->name[0] != '\0') {
512 lsm.cmd_type = LTTNG_ENABLE_EVENT;
513 } else {
514 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
515 }
516 memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
517
518 copy_string(lsm.session.name, handle->session_name,
519 sizeof(lsm.session.name));
520
521 return ask_sessiond(&lsm, NULL);
522 }
523
524 /*
525 * Disable event of a channel and domain.
526 */
527 int lttng_disable_event(struct lttng_handle *handle, const char *name,
528 const char *channel_name)
529 {
530 struct lttcomm_session_msg lsm;
531
532 if (!handle) {
533 return -1;
534 }
535
536 if (channel_name) {
537 copy_string(lsm.u.disable.channel_name, channel_name,
538 sizeof(lsm.u.disable.channel_name));
539 } else {
540 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
541 sizeof(lsm.u.disable.channel_name));
542 }
543
544 copy_lttng_domain(&lsm.domain, &handle->domain);
545
546 if (name != NULL) {
547 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
548 lsm.cmd_type = LTTNG_DISABLE_EVENT;
549 } else {
550 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
551 }
552
553 copy_string(lsm.session.name, handle->session_name,
554 sizeof(lsm.session.name));
555
556 return ask_sessiond(&lsm, NULL);
557 }
558
559 /*
560 * Enable channel per domain
561 */
562 int lttng_enable_channel(struct lttng_handle *handle,
563 struct lttng_channel *chan)
564 {
565 struct lttcomm_session_msg lsm;
566
567 if (!handle) {
568 return -1;
569 }
570
571 if (chan) {
572 memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
573 }
574
575 lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
576
577 copy_lttng_domain(&lsm.domain, &handle->domain);
578
579 copy_string(lsm.session.name, handle->session_name,
580 sizeof(lsm.session.name));
581
582 return ask_sessiond(&lsm, NULL);
583 }
584
585 /*
586 * All tracing will be stopped for registered events of the channel.
587 */
588 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
589 {
590 struct lttcomm_session_msg lsm;
591
592 if (!handle) {
593 return -1;
594 }
595
596 if (name) {
597 copy_string(lsm.u.disable.channel_name, name,
598 sizeof(lsm.u.disable.channel_name));
599 }
600
601 lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
602
603 copy_lttng_domain(&lsm.domain, &handle->domain);
604
605 copy_string(lsm.session.name, handle->session_name,
606 sizeof(lsm.session.name));
607
608 return ask_sessiond(&lsm, NULL);
609 }
610
611 /*
612 * List all available tracepoints of domain.
613 *
614 * Return the size (bytes) of the list and set the events array.
615 * On error, return negative value.
616 */
617 int lttng_list_tracepoints(struct lttng_handle *handle,
618 struct lttng_event **events)
619 {
620 int ret;
621 struct lttcomm_session_msg lsm;
622
623 if (!handle) {
624 return -1;
625 }
626
627 lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
628 copy_lttng_domain(&lsm.domain, &handle->domain);
629
630 ret = ask_sessiond(&lsm, (void **) events);
631 if (ret < 0) {
632 return ret;
633 }
634
635 return ret / sizeof(struct lttng_event);
636 }
637
638 /*
639 * Return a human readable string of code
640 */
641 const char *lttng_strerror(int code)
642 {
643 if (code > -LTTCOMM_OK) {
644 return "Ended with errors";
645 }
646
647 return lttcomm_get_readable_code(code);
648 }
649
650 /*
651 * Create a brand new session using name.
652 */
653 int lttng_create_session(const char *name, const char *path)
654 {
655 struct lttcomm_session_msg lsm;
656
657 lsm.cmd_type = LTTNG_CREATE_SESSION;
658 copy_string(lsm.session.name, name, sizeof(lsm.session.name));
659 copy_string(lsm.session.path, path, sizeof(lsm.session.path));
660
661 return ask_sessiond(&lsm, NULL);
662 }
663
664 /*
665 * Destroy session using name.
666 */
667 int lttng_destroy_session(struct lttng_handle *handle)
668 {
669 struct lttcomm_session_msg lsm;
670
671 if (!handle) {
672 return -1;
673 }
674
675 lsm.cmd_type = LTTNG_DESTROY_SESSION;
676 copy_string(lsm.session.name, handle->session_name,
677 sizeof(lsm.session.name));
678
679 return ask_sessiond(&lsm, NULL);
680 }
681
682 /*
683 * Ask the session daemon for all available sessions.
684 *
685 * Return number of session.
686 * On error, return negative value.
687 */
688 int lttng_list_sessions(struct lttng_session **sessions)
689 {
690 int ret;
691 struct lttcomm_session_msg lsm;
692
693 lsm.cmd_type = LTTNG_LIST_SESSIONS;
694 ret = ask_sessiond(&lsm, (void**) sessions);
695 if (ret < 0) {
696 return ret;
697 }
698
699 return ret / sizeof(struct lttng_session);
700 }
701
702 /*
703 * List domain of a session.
704 */
705 int lttng_list_domains(struct lttng_handle *handle,
706 struct lttng_domain **domains)
707 {
708 int ret;
709 struct lttcomm_session_msg lsm;
710
711 if (!handle) {
712 return -1;
713 }
714
715 lsm.cmd_type = LTTNG_LIST_DOMAINS;
716
717 copy_string(lsm.session.name, handle->session_name,
718 sizeof(lsm.session.name));
719
720 ret = ask_sessiond(&lsm, (void**) domains);
721 if (ret < 0) {
722 return ret;
723 }
724
725 return ret / sizeof(struct lttng_domain);
726 }
727
728 /*
729 * List channels of a session
730 */
731 int lttng_list_channels(struct lttng_handle *handle,
732 struct lttng_channel **channels)
733 {
734 int ret;
735 struct lttcomm_session_msg lsm;
736
737 if (!handle) {
738 return -1;
739 }
740
741 lsm.cmd_type = LTTNG_LIST_CHANNELS;
742 copy_string(lsm.session.name, handle->session_name,
743 sizeof(lsm.session.name));
744
745 copy_lttng_domain(&lsm.domain, &handle->domain);
746
747 ret = ask_sessiond(&lsm, (void**) channels);
748 if (ret < 0) {
749 return ret;
750 }
751
752 return ret / sizeof(struct lttng_channel);
753 }
754
755 /*
756 * List events of a session channel.
757 */
758 int lttng_list_events(struct lttng_handle *handle,
759 const char *channel_name, struct lttng_event **events)
760 {
761 int ret;
762 struct lttcomm_session_msg lsm;
763
764 if (!handle) {
765 return -1;
766 }
767
768 lsm.cmd_type = LTTNG_LIST_EVENTS;
769 copy_string(lsm.session.name, handle->session_name,
770 sizeof(lsm.session.name));
771 copy_string(lsm.u.list.channel_name, channel_name,
772 sizeof(lsm.u.list.channel_name));
773
774 copy_lttng_domain(&lsm.domain, &handle->domain);
775
776 ret = ask_sessiond(&lsm, (void**) events);
777 if (ret < 0) {
778 return ret;
779 }
780
781 return ret / sizeof(struct lttng_event);
782 }
783
784 /*
785 * lttng_set_tracing_group
786 *
787 * Set tracing group variable with name. This function
788 * allocate memory pointed by tracing_group.
789 */
790 int lttng_set_tracing_group(const char *name)
791 {
792 if (asprintf(&tracing_group, "%s", name) < 0) {
793 return -ENOMEM;
794 }
795
796 return 0;
797 }
798
799 /*
800 * lttng_calibrate
801 */
802 int lttng_calibrate(struct lttng_handle *handle,
803 struct lttng_calibrate *calibrate)
804 {
805 struct lttcomm_session_msg lsm;
806
807 if (!handle) {
808 return -1;
809 }
810
811 lsm.cmd_type = LTTNG_CALIBRATE;
812 copy_lttng_domain(&lsm.domain, &handle->domain);
813
814 memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
815
816 return ask_sessiond(&lsm, NULL);
817 }
818
819 /*
820 * Check if session daemon is alive.
821 *
822 * Return 1 if alive or 0 if not.
823 * On error return -1
824 */
825 int lttng_session_daemon_alive(void)
826 {
827 int ret;
828
829 ret = set_session_daemon_path();
830 if (ret < 0) {
831 /* Error */
832 return ret;
833 }
834
835 if (strlen(sessiond_sock_path) == 0) {
836 /* No socket path set. Weird error */
837 return -1;
838 }
839
840 ret = try_connect_sessiond(sessiond_sock_path);
841 if (ret < 0) {
842 /* Not alive */
843 return 0;
844 }
845
846 /* Is alive */
847 return 1;
848 }
849
850 /*
851 * lib constructor
852 */
853 static void __attribute__((constructor)) init()
854 {
855 /* Set default session group */
856 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
857 }
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