API change for lttng_get_readeable_code
[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 ret = 0;
338 goto end;
339 }
340
341 data = (void*) malloc(size);
342
343 /* Get payload data */
344 ret = recv_data_sessiond(data, size);
345 if (ret < 0) {
346 free(data);
347 goto end;
348 }
349
350 /*
351 * Extra protection not to dereference a NULL pointer. If buf is NULL at
352 * this point, an error is returned and data is freed.
353 */
354 if (buf == NULL) {
355 ret = -1;
356 free(data);
357 goto end;
358 }
359
360 *buf = data;
361 ret = size;
362
363 end:
364 disconnect_sessiond();
365 return ret;
366 }
367
368 /*
369 * Create lttng handle and return pointer.
370 */
371 struct lttng_handle *lttng_create_handle(const char *session_name,
372 struct lttng_domain *domain)
373 {
374 struct lttng_handle *handle;
375
376 handle = malloc(sizeof(struct lttng_handle));
377 if (handle == NULL) {
378 perror("malloc handle");
379 goto end;
380 }
381
382 /* Copy session name */
383 copy_string(handle->session_name, session_name,
384 sizeof(handle->session_name));
385
386 /* Copy lttng domain */
387 copy_lttng_domain(&handle->domain, domain);
388
389 end:
390 return handle;
391 }
392
393 /*
394 * Destroy handle by free(3) the pointer.
395 */
396 void lttng_destroy_handle(struct lttng_handle *handle)
397 {
398 if (handle) {
399 free(handle);
400 }
401 }
402
403 /*
404 * Register an outside consumer.
405 */
406 int lttng_register_consumer(struct lttng_handle *handle,
407 const char *socket_path)
408 {
409 struct lttcomm_session_msg lsm;
410
411 lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
412 copy_string(lsm.session.name, handle->session_name,
413 sizeof(lsm.session.name));
414 copy_lttng_domain(&lsm.domain, &handle->domain);
415
416 copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
417
418 return ask_sessiond(&lsm, NULL);
419 }
420
421 /*
422 * Start tracing for all trace of the session.
423 */
424 int lttng_start_tracing(struct lttng_handle *handle)
425 {
426 struct lttcomm_session_msg lsm;
427
428 if (!handle) {
429 return -1;
430 }
431
432 lsm.cmd_type = LTTNG_START_TRACE;
433 copy_string(lsm.session.name, handle->session_name,
434 sizeof(lsm.session.name));
435
436 return ask_sessiond(&lsm, NULL);
437 }
438
439 /*
440 * Stop tracing for all trace of the session.
441 */
442 int lttng_stop_tracing(struct lttng_handle *handle)
443 {
444 struct lttcomm_session_msg lsm;
445
446 lsm.cmd_type = LTTNG_STOP_TRACE;
447 copy_string(lsm.session.name, handle->session_name,
448 sizeof(lsm.session.name));
449
450 return ask_sessiond(&lsm, NULL);
451 }
452
453 /*
454 * Add context to event or/and channel.
455 */
456 int lttng_add_context(struct lttng_handle *handle,
457 struct lttng_event_context *ctx, const char *event_name,
458 const char *channel_name)
459 {
460 struct lttcomm_session_msg lsm;
461
462 if (!handle) {
463 return -1;
464 }
465
466 lsm.cmd_type = LTTNG_ADD_CONTEXT;
467
468 /* Copy channel name */
469 copy_string(lsm.u.context.channel_name, channel_name,
470 sizeof(lsm.u.context.channel_name));
471 /* Copy event name */
472 copy_string(lsm.u.context.event_name, event_name,
473 sizeof(lsm.u.context.event_name));
474
475 copy_lttng_domain(&lsm.domain, &handle->domain);
476
477 if (ctx) {
478 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
479 }
480
481 copy_string(lsm.session.name, handle->session_name,
482 sizeof(lsm.session.name));
483
484 return ask_sessiond(&lsm, NULL);
485 }
486
487 /*
488 * Enable event
489 */
490 int lttng_enable_event(struct lttng_handle *handle,
491 struct lttng_event *ev, const char *channel_name)
492 {
493 struct lttcomm_session_msg lsm;
494
495 if (!handle || ev == NULL) {
496 return -1;
497 }
498
499 if (channel_name == NULL) {
500 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
501 sizeof(lsm.u.enable.channel_name));
502 } else {
503 copy_string(lsm.u.enable.channel_name, channel_name,
504 sizeof(lsm.u.enable.channel_name));
505 }
506
507 copy_lttng_domain(&lsm.domain, &handle->domain);
508
509 if (ev->name[0] != '\0') {
510 lsm.cmd_type = LTTNG_ENABLE_EVENT;
511 } else {
512 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
513 }
514 memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
515
516 copy_string(lsm.session.name, handle->session_name,
517 sizeof(lsm.session.name));
518
519 return ask_sessiond(&lsm, NULL);
520 }
521
522 /*
523 * Disable event of a channel and domain.
524 */
525 int lttng_disable_event(struct lttng_handle *handle, const char *name,
526 const char *channel_name)
527 {
528 struct lttcomm_session_msg lsm;
529
530 if (!handle) {
531 return -1;
532 }
533
534 if (channel_name) {
535 copy_string(lsm.u.disable.channel_name, channel_name,
536 sizeof(lsm.u.disable.channel_name));
537 } else {
538 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
539 sizeof(lsm.u.disable.channel_name));
540 }
541
542 copy_lttng_domain(&lsm.domain, &handle->domain);
543
544 if (name != NULL) {
545 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
546 lsm.cmd_type = LTTNG_DISABLE_EVENT;
547 } else {
548 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
549 }
550
551 copy_string(lsm.session.name, handle->session_name,
552 sizeof(lsm.session.name));
553
554 return ask_sessiond(&lsm, NULL);
555 }
556
557 /*
558 * Enable channel per domain
559 */
560 int lttng_enable_channel(struct lttng_handle *handle,
561 struct lttng_channel *chan)
562 {
563 struct lttcomm_session_msg lsm;
564
565 if (!handle) {
566 return -1;
567 }
568
569 if (chan) {
570 memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
571 }
572
573 lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
574
575 copy_lttng_domain(&lsm.domain, &handle->domain);
576
577 copy_string(lsm.session.name, handle->session_name,
578 sizeof(lsm.session.name));
579
580 return ask_sessiond(&lsm, NULL);
581 }
582
583 /*
584 * All tracing will be stopped for registered events of the channel.
585 */
586 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
587 {
588 struct lttcomm_session_msg lsm;
589
590 if (!handle) {
591 return -1;
592 }
593
594 if (name) {
595 copy_string(lsm.u.disable.channel_name, name,
596 sizeof(lsm.u.disable.channel_name));
597 }
598
599 lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
600
601 copy_lttng_domain(&lsm.domain, &handle->domain);
602
603 copy_string(lsm.session.name, handle->session_name,
604 sizeof(lsm.session.name));
605
606 return ask_sessiond(&lsm, NULL);
607 }
608
609 /*
610 * List all available tracepoints of domain.
611 *
612 * Return the size (bytes) of the list and set the events array.
613 * On error, return negative value.
614 */
615 int lttng_list_tracepoints(struct lttng_handle *handle,
616 struct lttng_event **events)
617 {
618 int ret;
619 struct lttcomm_session_msg lsm;
620
621 if (!handle) {
622 return -1;
623 }
624
625 lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
626 copy_lttng_domain(&lsm.domain, &handle->domain);
627
628 ret = ask_sessiond(&lsm, (void **) events);
629 if (ret < 0) {
630 return ret;
631 }
632
633 return ret / sizeof(struct lttng_event);
634 }
635
636 /*
637 * Return a human readable string of code
638 */
639 const char *lttng_strerror(int code)
640 {
641 if (code > -LTTCOMM_OK) {
642 return "Ended with errors";
643 }
644
645 return lttcomm_get_readable_code(code);
646 }
647
648 /*
649 * Create a brand new session using name.
650 */
651 int lttng_create_session(const char *name, const char *path)
652 {
653 struct lttcomm_session_msg lsm;
654
655 lsm.cmd_type = LTTNG_CREATE_SESSION;
656 copy_string(lsm.session.name, name, sizeof(lsm.session.name));
657 copy_string(lsm.session.path, path, sizeof(lsm.session.path));
658
659 return ask_sessiond(&lsm, NULL);
660 }
661
662 /*
663 * Destroy session using name.
664 */
665 int lttng_destroy_session(struct lttng_handle *handle)
666 {
667 struct lttcomm_session_msg lsm;
668
669 if (!handle) {
670 return -1;
671 }
672
673 lsm.cmd_type = LTTNG_DESTROY_SESSION;
674 copy_string(lsm.session.name, handle->session_name,
675 sizeof(lsm.session.name));
676
677 return ask_sessiond(&lsm, NULL);
678 }
679
680 /*
681 * Ask the session daemon for all available sessions.
682 *
683 * Return number of session.
684 * On error, return negative value.
685 */
686 int lttng_list_sessions(struct lttng_session **sessions)
687 {
688 int ret;
689 struct lttcomm_session_msg lsm;
690
691 lsm.cmd_type = LTTNG_LIST_SESSIONS;
692 ret = ask_sessiond(&lsm, (void**) sessions);
693 if (ret < 0) {
694 return ret;
695 }
696
697 return ret / sizeof(struct lttng_session);
698 }
699
700 /*
701 * List domain of a session.
702 */
703 int lttng_list_domains(struct lttng_handle *handle,
704 struct lttng_domain **domains)
705 {
706 int ret;
707 struct lttcomm_session_msg lsm;
708
709 if (!handle) {
710 return -1;
711 }
712
713 lsm.cmd_type = LTTNG_LIST_DOMAINS;
714
715 copy_string(lsm.session.name, handle->session_name,
716 sizeof(lsm.session.name));
717
718 ret = ask_sessiond(&lsm, (void**) domains);
719 if (ret < 0) {
720 return ret;
721 }
722
723 return ret / sizeof(struct lttng_domain);
724 }
725
726 /*
727 * List channels of a session
728 */
729 int lttng_list_channels(struct lttng_handle *handle,
730 struct lttng_channel **channels)
731 {
732 int ret;
733 struct lttcomm_session_msg lsm;
734
735 if (!handle) {
736 return -1;
737 }
738
739 lsm.cmd_type = LTTNG_LIST_CHANNELS;
740 copy_string(lsm.session.name, handle->session_name,
741 sizeof(lsm.session.name));
742
743 copy_lttng_domain(&lsm.domain, &handle->domain);
744
745 ret = ask_sessiond(&lsm, (void**) channels);
746 if (ret < 0) {
747 return ret;
748 }
749
750 return ret / sizeof(struct lttng_channel);
751 }
752
753 /*
754 * List events of a session channel.
755 */
756 int lttng_list_events(struct lttng_handle *handle,
757 const char *channel_name, struct lttng_event **events)
758 {
759 int ret;
760 struct lttcomm_session_msg lsm;
761
762 if (!handle) {
763 return -1;
764 }
765
766 lsm.cmd_type = LTTNG_LIST_EVENTS;
767 copy_string(lsm.session.name, handle->session_name,
768 sizeof(lsm.session.name));
769 copy_string(lsm.u.list.channel_name, channel_name,
770 sizeof(lsm.u.list.channel_name));
771
772 copy_lttng_domain(&lsm.domain, &handle->domain);
773
774 ret = ask_sessiond(&lsm, (void**) events);
775 if (ret < 0) {
776 return ret;
777 }
778
779 return ret / sizeof(struct lttng_event);
780 }
781
782 /*
783 * lttng_set_tracing_group
784 *
785 * Set tracing group variable with name. This function
786 * allocate memory pointed by tracing_group.
787 */
788 int lttng_set_tracing_group(const char *name)
789 {
790 if (asprintf(&tracing_group, "%s", name) < 0) {
791 return -ENOMEM;
792 }
793
794 return 0;
795 }
796
797 /*
798 * lttng_calibrate
799 */
800 int lttng_calibrate(struct lttng_handle *handle,
801 struct lttng_calibrate *calibrate)
802 {
803 struct lttcomm_session_msg lsm;
804
805 if (!handle) {
806 return -1;
807 }
808
809 lsm.cmd_type = LTTNG_CALIBRATE;
810 copy_lttng_domain(&lsm.domain, &handle->domain);
811
812 memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
813
814 return ask_sessiond(&lsm, NULL);
815 }
816
817 /*
818 * Check if session daemon is alive.
819 *
820 * Return 1 if alive or 0 if not.
821 * On error return -1
822 */
823 int lttng_session_daemon_alive(void)
824 {
825 int ret;
826
827 ret = set_session_daemon_path();
828 if (ret < 0) {
829 /* Error */
830 return ret;
831 }
832
833 if (strlen(sessiond_sock_path) == 0) {
834 /* No socket path set. Weird error */
835 return -1;
836 }
837
838 ret = try_connect_sessiond(sessiond_sock_path);
839 if (ret < 0) {
840 /* Not alive */
841 return 0;
842 }
843
844 /* Is alive */
845 return 1;
846 }
847
848 /*
849 * lib constructor
850 */
851 static void __attribute__((constructor)) init()
852 {
853 /* Set default session group */
854 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
855 }
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