Remove all remaining sessiond kernel command
[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. If unknown domain, default domain
283 * will be the kernel.
284 */
285 static void copy_lttng_domain(struct lttng_domain *dom)
286 {
287 if (dom) {
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 break;
296 default:
297 lsm.domain.type = LTTNG_DOMAIN_KERNEL;
298 break;
299 }
300 }
301 }
302
303 /*
304 * Copy string from src to dst and enforce null terminated byte.
305 */
306 static void copy_string(char *dst, const char *src, size_t len)
307 {
308 if (src && dst) {
309 strncpy(dst, src, len);
310 /* Enforce the NULL terminated byte */
311 dst[len - 1] = '\0';
312 }
313 }
314
315 /*
316 * Start tracing for all trace of the session.
317 */
318 int lttng_start_tracing(const char *session_name)
319 {
320 copy_string(lsm.session.name, session_name, NAME_MAX);
321 return ask_sessiond(LTTNG_START_TRACE, NULL);
322 }
323
324 /*
325 * Stop tracing for all trace of the session.
326 */
327 int lttng_stop_tracing(const char *session_name)
328 {
329 copy_string(lsm.session.name, session_name, NAME_MAX);
330 return ask_sessiond(LTTNG_STOP_TRACE, NULL);
331 }
332
333 /*
334 * lttng_add_context
335 */
336 int lttng_add_context(struct lttng_domain *domain,
337 struct lttng_event_context *ctx, const char *event_name,
338 const char *channel_name)
339 {
340 copy_string(lsm.u.context.channel_name, channel_name, NAME_MAX);
341 copy_string(lsm.u.context.event_name, event_name, NAME_MAX);
342 copy_lttng_domain(domain);
343
344 if (ctx) {
345 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
346 }
347
348 return ask_sessiond(LTTNG_ADD_CONTEXT, NULL);
349 }
350
351 /*
352 * lttng_enable_event
353 */
354 int lttng_enable_event(struct lttng_domain *domain,
355 struct lttng_event *ev, const char *channel_name)
356 {
357 int ret;
358
359 if (channel_name == NULL) {
360 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
361 } else {
362 copy_string(lsm.u.enable.channel_name, channel_name, NAME_MAX);
363 }
364
365 copy_lttng_domain(domain);
366
367 if (ev == NULL) {
368 ret = ask_sessiond(LTTNG_ENABLE_ALL_EVENT, NULL);
369 } else {
370 memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event));
371 ret = ask_sessiond(LTTNG_ENABLE_EVENT, NULL);
372 }
373
374 return ret;
375 }
376
377 /*
378 * Disable event of a channel and domain.
379 */
380 int lttng_disable_event(struct lttng_domain *domain, const char *name,
381 const char *channel_name)
382 {
383 int ret = -1;
384
385 if (channel_name == NULL) {
386 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
387 } else {
388 copy_string(lsm.u.disable.channel_name, channel_name, NAME_MAX);
389 }
390
391 copy_lttng_domain(domain);
392
393 if (name == NULL) {
394 ret = ask_sessiond(LTTNG_DISABLE_ALL_EVENT, NULL);
395 } else {
396 copy_string(lsm.u.disable.name, name, NAME_MAX);
397 ret = ask_sessiond(LTTNG_DISABLE_EVENT, NULL);
398 }
399
400 return ret;
401 }
402
403 /*
404 * Enable channel per domain
405 */
406 int lttng_enable_channel(struct lttng_domain *domain,
407 struct lttng_channel *chan)
408 {
409 if (chan) {
410 memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
411 }
412
413 copy_lttng_domain(domain);
414
415 return ask_sessiond(LTTNG_ENABLE_CHANNEL, NULL);
416 }
417
418 /*
419 * All tracing will be stopped for registered events of the channel.
420 */
421 int lttng_disable_channel(struct lttng_domain *domain, const char *name)
422 {
423 copy_string(lsm.u.disable.channel_name, name, NAME_MAX);
424 copy_lttng_domain(domain);
425
426 return ask_sessiond(LTTNG_DISABLE_CHANNEL, NULL);
427 }
428
429 /*
430 * List all available tracepoints of domain.
431 *
432 * Return the size (bytes) of the list and set the events array.
433 * On error, return negative value.
434 */
435 int lttng_list_tracepoints(struct lttng_domain *domain,
436 struct lttng_event **events)
437 {
438 int ret;
439
440 copy_lttng_domain(domain);
441
442 ret = ask_sessiond(LTTNG_LIST_TRACEPOINTS, (void **) events);
443 if (ret < 0) {
444 return ret;
445 }
446
447 return ret / sizeof(struct lttng_event);
448 }
449
450 /*
451 * Return a human readable string of code
452 */
453 const char *lttng_get_readable_code(int code)
454 {
455 if (code > -LTTCOMM_OK) {
456 return "Ended with errors";
457 }
458
459 return lttcomm_get_readable_code(code);
460 }
461
462 /*
463 * Create a brand new session using name.
464 */
465 int lttng_create_session(const char *name, const char *path)
466 {
467 copy_string(lsm.session.name, name, NAME_MAX);
468 copy_string(lsm.session.path, path, PATH_MAX);
469 return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
470 }
471
472 /*
473 * Destroy session using name.
474 */
475 int lttng_destroy_session(const char *name)
476 {
477 copy_string(lsm.session.name, name, NAME_MAX);
478 return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
479 }
480
481 /*
482 * Ask the session daemon for all available sessions.
483 *
484 * Return number of session.
485 * On error, return negative value.
486 */
487 int lttng_list_sessions(struct lttng_session **sessions)
488 {
489 int ret;
490
491 ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
492 if (ret < 0) {
493 return ret;
494 }
495
496 return ret / sizeof(struct lttng_session);
497 }
498
499 /*
500 * List domain of a session.
501 */
502 int lttng_list_domains(const char *session_name, struct lttng_domain **domains)
503 {
504 int ret;
505
506 copy_string(lsm.session.name, session_name, NAME_MAX);
507 ret = ask_sessiond(LTTNG_LIST_DOMAINS, (void**) domains);
508 if (ret < 0) {
509 return ret;
510 }
511
512 return ret / sizeof(struct lttng_domain);
513 }
514
515 /*
516 * List channels of a session
517 */
518 int lttng_list_channels(struct lttng_domain *domain,
519 const char *session_name, struct lttng_channel **channels)
520 {
521 int ret;
522
523 copy_string(lsm.session.name, session_name, NAME_MAX);
524 copy_lttng_domain(domain);
525
526 ret = ask_sessiond(LTTNG_LIST_CHANNELS, (void**) channels);
527 if (ret < 0) {
528 return ret;
529 }
530
531 return ret / sizeof(struct lttng_channel);
532 }
533
534 /*
535 * List events of a session channel.
536 */
537 int lttng_list_events(struct lttng_domain *domain,
538 const char *session_name, const char *channel_name,
539 struct lttng_event **events)
540 {
541 int ret;
542
543 copy_string(lsm.session.name, session_name, NAME_MAX);
544 copy_string(lsm.u.list.channel_name, channel_name, NAME_MAX);
545 copy_lttng_domain(domain);
546
547 ret = ask_sessiond(LTTNG_LIST_EVENTS, (void**) events);
548 if (ret < 0) {
549 return ret;
550 }
551
552 return ret / sizeof(struct lttng_event);
553 }
554
555 /*
556 * Set session name for the current lsm.
557 */
558 void lttng_set_session_name(const char *name)
559 {
560 copy_string(lsm.session.name, name, NAME_MAX);
561 }
562
563 /*
564 * lttng_set_tracing_group
565 *
566 * Set tracing group variable with name. This function
567 * allocate memory pointed by tracing_group.
568 */
569 int lttng_set_tracing_group(const char *name)
570 {
571 if (asprintf(&tracing_group, "%s", name) < 0) {
572 return -ENOMEM;
573 }
574
575 return 0;
576 }
577
578 /*
579 * lttng_check_session_daemon
580 *
581 * Yes, return 1
582 * No, return 0
583 * Error, return negative value
584 */
585 int lttng_session_daemon_alive(void)
586 {
587 int ret;
588
589 ret = set_session_daemon_path();
590 if (ret < 0) {
591 /* Error */
592 return ret;
593 }
594
595 /* If socket exist, we consider the daemon started */
596 ret = access(sessiond_sock_path, F_OK);
597 if (ret < 0) {
598 /* Not alive */
599 return 0;
600 }
601
602 /* Is alive */
603 return 1;
604 }
605
606 /*
607 * lib constructor
608 */
609 static void __attribute__((constructor)) init()
610 {
611 /* Set default session group */
612 lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
613 }
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