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[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c
1 /*
2 * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License, version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 51
15 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #define _GNU_SOURCE
19 #include <assert.h>
20 #include <urcu/list.h>
21 #include <urcu/uatomic.h>
22
23 #include <common/defaults.h>
24 #include <common/common.h>
25 #include <common/sessiond-comm/sessiond-comm.h>
26 #include <common/relayd/relayd.h>
27
28 #include "channel.h"
29 #include "consumer.h"
30 #include "event.h"
31 #include "kernel.h"
32 #include "kernel-consumer.h"
33 #include "lttng-sessiond.h"
34 #include "utils.h"
35
36 #include "cmd.h"
37
38 /*
39 * Used to keep a unique index for each relayd socket created where this value
40 * is associated with streams on the consumer so it can match the right relayd
41 * to send to.
42 *
43 * This value should be incremented atomically for safety purposes and future
44 * possible concurrent access.
45 */
46 static unsigned int relayd_net_seq_idx;
47
48 /*
49 * Create a session path used by list_lttng_sessions for the case that the
50 * session consumer is on the network.
51 */
52 static int build_network_session_path(char *dst, size_t size,
53 struct ltt_session *session)
54 {
55 int ret, kdata_port, udata_port;
56 struct lttng_uri *kuri = NULL, *uuri = NULL, *uri = NULL;
57 char tmp_uurl[PATH_MAX], tmp_urls[PATH_MAX];
58
59 assert(session);
60 assert(dst);
61
62 memset(tmp_urls, 0, sizeof(tmp_urls));
63 memset(tmp_uurl, 0, sizeof(tmp_uurl));
64
65 kdata_port = udata_port = DEFAULT_NETWORK_DATA_PORT;
66
67 if (session->kernel_session && session->kernel_session->consumer) {
68 kuri = &session->kernel_session->consumer->dst.net.control;
69 kdata_port = session->kernel_session->consumer->dst.net.data.port;
70 }
71
72 if (session->ust_session && session->ust_session->consumer) {
73 uuri = &session->ust_session->consumer->dst.net.control;
74 udata_port = session->ust_session->consumer->dst.net.data.port;
75 }
76
77 if (uuri == NULL && kuri == NULL) {
78 uri = &session->consumer->dst.net.control;
79 kdata_port = session->consumer->dst.net.data.port;
80 } else if (kuri && uuri) {
81 ret = uri_compare(kuri, uuri);
82 if (ret) {
83 /* Not Equal */
84 uri = kuri;
85 /* Build uuri URL string */
86 ret = uri_to_str_url(uuri, tmp_uurl, sizeof(tmp_uurl));
87 if (ret < 0) {
88 goto error;
89 }
90 } else {
91 uri = kuri;
92 }
93 } else if (kuri && uuri == NULL) {
94 uri = kuri;
95 } else if (uuri && kuri == NULL) {
96 uri = uuri;
97 }
98
99 ret = uri_to_str_url(uri, tmp_urls, sizeof(tmp_urls));
100 if (ret < 0) {
101 goto error;
102 }
103
104 if (strlen(tmp_uurl) > 0) {
105 ret = snprintf(dst, size, "[K]: %s [data: %d] -- [U]: %s [data: %d]",
106 tmp_urls, kdata_port, tmp_uurl, udata_port);
107 } else {
108 ret = snprintf(dst, size, "%s [data: %d]", tmp_urls, kdata_port);
109 }
110
111 error:
112 return ret;
113 }
114
115 /*
116 * Fill lttng_channel array of all channels.
117 */
118 static void list_lttng_channels(int domain, struct ltt_session *session,
119 struct lttng_channel *channels)
120 {
121 int i = 0;
122 struct ltt_kernel_channel *kchan;
123
124 DBG("Listing channels for session %s", session->name);
125
126 switch (domain) {
127 case LTTNG_DOMAIN_KERNEL:
128 /* Kernel channels */
129 if (session->kernel_session != NULL) {
130 cds_list_for_each_entry(kchan,
131 &session->kernel_session->channel_list.head, list) {
132 /* Copy lttng_channel struct to array */
133 memcpy(&channels[i], kchan->channel, sizeof(struct lttng_channel));
134 channels[i].enabled = kchan->enabled;
135 i++;
136 }
137 }
138 break;
139 case LTTNG_DOMAIN_UST:
140 {
141 struct lttng_ht_iter iter;
142 struct ltt_ust_channel *uchan;
143
144 cds_lfht_for_each_entry(session->ust_session->domain_global.channels->ht,
145 &iter.iter, uchan, node.node) {
146 strncpy(channels[i].name, uchan->name, LTTNG_SYMBOL_NAME_LEN);
147 channels[i].attr.overwrite = uchan->attr.overwrite;
148 channels[i].attr.subbuf_size = uchan->attr.subbuf_size;
149 channels[i].attr.num_subbuf = uchan->attr.num_subbuf;
150 channels[i].attr.switch_timer_interval =
151 uchan->attr.switch_timer_interval;
152 channels[i].attr.read_timer_interval =
153 uchan->attr.read_timer_interval;
154 channels[i].enabled = uchan->enabled;
155 switch (uchan->attr.output) {
156 case LTTNG_UST_MMAP:
157 default:
158 channels[i].attr.output = LTTNG_EVENT_MMAP;
159 break;
160 }
161 i++;
162 }
163 break;
164 }
165 default:
166 break;
167 }
168 }
169
170 /*
171 * Create a list of ust global domain events.
172 */
173 static int list_lttng_ust_global_events(char *channel_name,
174 struct ltt_ust_domain_global *ust_global, struct lttng_event **events)
175 {
176 int i = 0, ret = 0;
177 unsigned int nb_event = 0;
178 struct lttng_ht_iter iter;
179 struct lttng_ht_node_str *node;
180 struct ltt_ust_channel *uchan;
181 struct ltt_ust_event *uevent;
182 struct lttng_event *tmp;
183
184 DBG("Listing UST global events for channel %s", channel_name);
185
186 rcu_read_lock();
187
188 lttng_ht_lookup(ust_global->channels, (void *)channel_name, &iter);
189 node = lttng_ht_iter_get_node_str(&iter);
190 if (node == NULL) {
191 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
192 goto error;
193 }
194
195 uchan = caa_container_of(&node->node, struct ltt_ust_channel, node.node);
196
197 nb_event += lttng_ht_get_count(uchan->events);
198
199 if (nb_event == 0) {
200 ret = nb_event;
201 goto error;
202 }
203
204 DBG3("Listing UST global %d events", nb_event);
205
206 tmp = zmalloc(nb_event * sizeof(struct lttng_event));
207 if (tmp == NULL) {
208 ret = LTTNG_ERR_FATAL;
209 goto error;
210 }
211
212 cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent, node.node) {
213 strncpy(tmp[i].name, uevent->attr.name, LTTNG_SYMBOL_NAME_LEN);
214 tmp[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
215 tmp[i].enabled = uevent->enabled;
216
217 switch (uevent->attr.instrumentation) {
218 case LTTNG_UST_TRACEPOINT:
219 tmp[i].type = LTTNG_EVENT_TRACEPOINT;
220 break;
221 case LTTNG_UST_PROBE:
222 tmp[i].type = LTTNG_EVENT_PROBE;
223 break;
224 case LTTNG_UST_FUNCTION:
225 tmp[i].type = LTTNG_EVENT_FUNCTION;
226 break;
227 }
228
229 tmp[i].loglevel = uevent->attr.loglevel;
230 switch (uevent->attr.loglevel_type) {
231 case LTTNG_UST_LOGLEVEL_ALL:
232 tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
233 break;
234 case LTTNG_UST_LOGLEVEL_RANGE:
235 tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
236 break;
237 case LTTNG_UST_LOGLEVEL_SINGLE:
238 tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
239 break;
240 }
241 if (uevent->filter) {
242 tmp[i].filter = 1;
243 }
244 i++;
245 }
246
247 ret = nb_event;
248 *events = tmp;
249
250 error:
251 rcu_read_unlock();
252 return ret;
253 }
254
255 /*
256 * Fill lttng_event array of all kernel events in the channel.
257 */
258 static int list_lttng_kernel_events(char *channel_name,
259 struct ltt_kernel_session *kernel_session, struct lttng_event **events)
260 {
261 int i = 0, ret;
262 unsigned int nb_event;
263 struct ltt_kernel_event *event;
264 struct ltt_kernel_channel *kchan;
265
266 kchan = trace_kernel_get_channel_by_name(channel_name, kernel_session);
267 if (kchan == NULL) {
268 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
269 goto error;
270 }
271
272 nb_event = kchan->event_count;
273
274 DBG("Listing events for channel %s", kchan->channel->name);
275
276 if (nb_event == 0) {
277 goto end;
278 }
279
280 *events = zmalloc(nb_event * sizeof(struct lttng_event));
281 if (*events == NULL) {
282 ret = LTTNG_ERR_FATAL;
283 goto error;
284 }
285
286 /* Kernel channels */
287 cds_list_for_each_entry(event, &kchan->events_list.head , list) {
288 strncpy((*events)[i].name, event->event->name, LTTNG_SYMBOL_NAME_LEN);
289 (*events)[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
290 (*events)[i].enabled = event->enabled;
291
292 switch (event->event->instrumentation) {
293 case LTTNG_KERNEL_TRACEPOINT:
294 (*events)[i].type = LTTNG_EVENT_TRACEPOINT;
295 break;
296 case LTTNG_KERNEL_KPROBE:
297 case LTTNG_KERNEL_KRETPROBE:
298 (*events)[i].type = LTTNG_EVENT_PROBE;
299 memcpy(&(*events)[i].attr.probe, &event->event->u.kprobe,
300 sizeof(struct lttng_kernel_kprobe));
301 break;
302 case LTTNG_KERNEL_FUNCTION:
303 (*events)[i].type = LTTNG_EVENT_FUNCTION;
304 memcpy(&((*events)[i].attr.ftrace), &event->event->u.ftrace,
305 sizeof(struct lttng_kernel_function));
306 break;
307 case LTTNG_KERNEL_NOOP:
308 (*events)[i].type = LTTNG_EVENT_NOOP;
309 break;
310 case LTTNG_KERNEL_SYSCALL:
311 (*events)[i].type = LTTNG_EVENT_SYSCALL;
312 break;
313 case LTTNG_KERNEL_ALL:
314 assert(0);
315 break;
316 }
317 i++;
318 }
319
320 end:
321 return nb_event;
322
323 error:
324 /* Negate the error code to differentiate the size from an error */
325 return -ret;
326 }
327
328 /*
329 * Add URI so the consumer output object. Set the correct path depending on the
330 * domain adding the default trace directory.
331 */
332 static int add_uri_to_consumer(struct consumer_output *consumer,
333 struct lttng_uri *uri, int domain, const char *session_name)
334 {
335 int ret = LTTNG_OK;
336 const char *default_trace_dir;
337
338 assert(uri);
339
340 if (consumer == NULL) {
341 DBG("No consumer detected. Don't add URI. Stopping.");
342 ret = LTTNG_ERR_NO_CONSUMER;
343 goto error;
344 }
345
346 switch (domain) {
347 case LTTNG_DOMAIN_KERNEL:
348 default_trace_dir = DEFAULT_KERNEL_TRACE_DIR;
349 break;
350 case LTTNG_DOMAIN_UST:
351 default_trace_dir = DEFAULT_UST_TRACE_DIR;
352 break;
353 default:
354 /*
355 * This case is possible is we try to add the URI to the global tracing
356 * session consumer object which in this case there is no subdir.
357 */
358 default_trace_dir = "";
359 }
360
361 switch (uri->dtype) {
362 case LTTNG_DST_IPV4:
363 case LTTNG_DST_IPV6:
364 DBG2("Setting network URI to consumer");
365
366 /* Set URI into consumer output object */
367 ret = consumer_set_network_uri(consumer, uri);
368 if (ret < 0) {
369 ret = LTTNG_ERR_FATAL;
370 goto error;
371 } else if (ret == 1) {
372 /*
373 * URI was the same in the consumer so we do not append the subdir
374 * again so to not duplicate output dir.
375 */
376 goto error;
377 }
378
379 if (uri->stype == LTTNG_STREAM_CONTROL && strlen(uri->subdir) == 0) {
380 ret = consumer_set_subdir(consumer, session_name);
381 if (ret < 0) {
382 ret = LTTNG_ERR_FATAL;
383 goto error;
384 }
385 }
386
387 if (uri->stype == LTTNG_STREAM_CONTROL) {
388 /* On a new subdir, reappend the default trace dir. */
389 strncat(consumer->subdir, default_trace_dir,
390 sizeof(consumer->subdir) - strlen(consumer->subdir) - 1);
391 DBG3("Append domain trace name to subdir %s", consumer->subdir);
392 }
393
394 break;
395 case LTTNG_DST_PATH:
396 DBG2("Setting trace directory path from URI to %s", uri->dst.path);
397 memset(consumer->dst.trace_path, 0,
398 sizeof(consumer->dst.trace_path));
399 strncpy(consumer->dst.trace_path, uri->dst.path,
400 sizeof(consumer->dst.trace_path));
401 /* Append default trace dir */
402 strncat(consumer->dst.trace_path, default_trace_dir,
403 sizeof(consumer->dst.trace_path) -
404 strlen(consumer->dst.trace_path) - 1);
405 /* Flag consumer as local. */
406 consumer->type = CONSUMER_DST_LOCAL;
407 break;
408 }
409
410 error:
411 return ret;
412 }
413
414 /*
415 * Init tracing by creating trace directory and sending fds kernel consumer.
416 */
417 static int init_kernel_tracing(struct ltt_kernel_session *session)
418 {
419 int ret = 0;
420 struct lttng_ht_iter iter;
421 struct consumer_socket *socket;
422
423 assert(session);
424
425 if (session->consumer_fds_sent == 0 && session->consumer != NULL) {
426 cds_lfht_for_each_entry(session->consumer->socks->ht, &iter.iter,
427 socket, node.node) {
428 /* Code flow error */
429 assert(socket->fd >= 0);
430
431 pthread_mutex_lock(socket->lock);
432 ret = kernel_consumer_send_session(socket->fd, session);
433 pthread_mutex_unlock(socket->lock);
434 if (ret < 0) {
435 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
436 goto error;
437 }
438 }
439 }
440
441 error:
442 return ret;
443 }
444
445 /*
446 * Create a socket to the relayd using the URI.
447 *
448 * On success, the relayd_sock pointer is set to the created socket.
449 * Else, it's stays untouched and a lttcomm error code is returned.
450 */
451 static int create_connect_relayd(struct consumer_output *output,
452 const char *session_name, struct lttng_uri *uri,
453 struct lttcomm_sock **relayd_sock)
454 {
455 int ret;
456 struct lttcomm_sock *sock;
457
458 /* Create socket object from URI */
459 sock = lttcomm_alloc_sock_from_uri(uri);
460 if (sock == NULL) {
461 ret = LTTNG_ERR_FATAL;
462 goto error;
463 }
464
465 ret = lttcomm_create_sock(sock);
466 if (ret < 0) {
467 ret = LTTNG_ERR_FATAL;
468 goto error;
469 }
470
471 /* Connect to relayd so we can proceed with a session creation. */
472 ret = relayd_connect(sock);
473 if (ret < 0) {
474 ERR("Unable to reach lttng-relayd");
475 ret = LTTNG_ERR_RELAYD_CONNECT_FAIL;
476 goto free_sock;
477 }
478
479 /* Create socket for control stream. */
480 if (uri->stype == LTTNG_STREAM_CONTROL) {
481 DBG3("Creating relayd stream socket from URI");
482
483 /* Check relayd version */
484 ret = relayd_version_check(sock, RELAYD_VERSION_COMM_MAJOR,
485 RELAYD_VERSION_COMM_MINOR);
486 if (ret < 0) {
487 ret = LTTNG_ERR_RELAYD_VERSION_FAIL;
488 goto close_sock;
489 }
490 } else if (uri->stype == LTTNG_STREAM_DATA) {
491 DBG3("Creating relayd data socket from URI");
492 } else {
493 /* Command is not valid */
494 ERR("Relayd invalid stream type: %d", uri->stype);
495 ret = LTTNG_ERR_INVALID;
496 goto close_sock;
497 }
498
499 *relayd_sock = sock;
500
501 return LTTNG_OK;
502
503 close_sock:
504 if (sock) {
505 (void) relayd_close(sock);
506 }
507 free_sock:
508 if (sock) {
509 lttcomm_destroy_sock(sock);
510 }
511 error:
512 return ret;
513 }
514
515 /*
516 * Connect to the relayd using URI and send the socket to the right consumer.
517 */
518 static int send_consumer_relayd_socket(int domain, struct ltt_session *session,
519 struct lttng_uri *relayd_uri, struct consumer_output *consumer,
520 int consumer_fd)
521 {
522 int ret;
523 struct lttcomm_sock *sock = NULL;
524
525 /* Set the network sequence index if not set. */
526 if (consumer->net_seq_index == -1) {
527 /*
528 * Increment net_seq_idx because we are about to transfer the
529 * new relayd socket to the consumer.
530 */
531 uatomic_inc(&relayd_net_seq_idx);
532 /* Assign unique key so the consumer can match streams */
533 uatomic_set(&consumer->net_seq_index,
534 uatomic_read(&relayd_net_seq_idx));
535 }
536
537 /* Connect to relayd and make version check if uri is the control. */
538 ret = create_connect_relayd(consumer, session->name, relayd_uri, &sock);
539 if (ret != LTTNG_OK) {
540 goto close_sock;
541 }
542
543 /* If the control socket is connected, network session is ready */
544 if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
545 session->net_handle = 1;
546 }
547
548 /* Send relayd socket to consumer. */
549 ret = consumer_send_relayd_socket(consumer_fd, sock,
550 consumer, relayd_uri->stype);
551 if (ret < 0) {
552 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
553 goto close_sock;
554 }
555
556 /* Flag that the corresponding socket was sent. */
557 if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
558 consumer->dst.net.control_sock_sent = 1;
559 } else if (relayd_uri->stype == LTTNG_STREAM_DATA) {
560 consumer->dst.net.data_sock_sent = 1;
561 }
562
563 ret = LTTNG_OK;
564
565 /*
566 * Close socket which was dup on the consumer side. The session daemon does
567 * NOT keep track of the relayd socket(s) once transfer to the consumer.
568 */
569
570 close_sock:
571 if (sock) {
572 (void) relayd_close(sock);
573 lttcomm_destroy_sock(sock);
574 }
575
576 return ret;
577 }
578
579 /*
580 * Send both relayd sockets to a specific consumer and domain. This is a
581 * helper function to facilitate sending the information to the consumer for a
582 * session.
583 */
584 static int send_consumer_relayd_sockets(int domain,
585 struct ltt_session *session, struct consumer_output *consumer, int fd)
586 {
587 int ret;
588
589 assert(session);
590 assert(consumer);
591
592 /* Sending control relayd socket. */
593 if (!consumer->dst.net.control_sock_sent) {
594 ret = send_consumer_relayd_socket(domain, session,
595 &consumer->dst.net.control, consumer, fd);
596 if (ret != LTTNG_OK) {
597 goto error;
598 }
599 }
600
601 /* Sending data relayd socket. */
602 if (!consumer->dst.net.data_sock_sent) {
603 ret = send_consumer_relayd_socket(domain, session,
604 &consumer->dst.net.data, consumer, fd);
605 if (ret != LTTNG_OK) {
606 goto error;
607 }
608 }
609
610 error:
611 return ret;
612 }
613
614 /*
615 * Setup relayd connections for a tracing session. First creates the socket to
616 * the relayd and send them to the right domain consumer. Consumer type MUST be
617 * network.
618 */
619 static int setup_relayd(struct ltt_session *session)
620 {
621 int ret = LTTNG_OK;
622 struct ltt_ust_session *usess;
623 struct ltt_kernel_session *ksess;
624 struct consumer_socket *socket;
625 struct lttng_ht_iter iter;
626
627 assert(session);
628
629 usess = session->ust_session;
630 ksess = session->kernel_session;
631
632 DBG2("Setting relayd for session %s", session->name);
633
634 if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
635 && usess->consumer->enabled) {
636 /* For each consumer socket, send relayd sockets */
637 cds_lfht_for_each_entry(usess->consumer->socks->ht, &iter.iter,
638 socket, node.node) {
639 /* Code flow error */
640 assert(socket->fd >= 0);
641
642 pthread_mutex_lock(socket->lock);
643 send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session,
644 usess->consumer, socket->fd);
645 pthread_mutex_unlock(socket->lock);
646 if (ret != LTTNG_OK) {
647 goto error;
648 }
649 }
650 }
651
652 if (ksess && ksess->consumer && ksess->consumer->type == CONSUMER_DST_NET
653 && ksess->consumer->enabled) {
654 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
655 socket, node.node) {
656 /* Code flow error */
657 assert(socket->fd >= 0);
658
659 pthread_mutex_lock(socket->lock);
660 send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session,
661 ksess->consumer, socket->fd);
662 pthread_mutex_unlock(socket->lock);
663 if (ret != LTTNG_OK) {
664 goto error;
665 }
666 }
667 }
668
669 error:
670 return ret;
671 }
672
673 /*
674 * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
675 */
676 int cmd_disable_channel(struct ltt_session *session, int domain,
677 char *channel_name)
678 {
679 int ret;
680 struct ltt_ust_session *usess;
681
682 usess = session->ust_session;
683
684 switch (domain) {
685 case LTTNG_DOMAIN_KERNEL:
686 {
687 ret = channel_kernel_disable(session->kernel_session,
688 channel_name);
689 if (ret != LTTNG_OK) {
690 goto error;
691 }
692
693 kernel_wait_quiescent(kernel_tracer_fd);
694 break;
695 }
696 case LTTNG_DOMAIN_UST:
697 {
698 struct ltt_ust_channel *uchan;
699 struct lttng_ht *chan_ht;
700
701 chan_ht = usess->domain_global.channels;
702
703 uchan = trace_ust_find_channel_by_name(chan_ht, channel_name);
704 if (uchan == NULL) {
705 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
706 goto error;
707 }
708
709 ret = channel_ust_disable(usess, domain, uchan);
710 if (ret != LTTNG_OK) {
711 goto error;
712 }
713 break;
714 }
715 #if 0
716 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
717 case LTTNG_DOMAIN_UST_EXEC_NAME:
718 case LTTNG_DOMAIN_UST_PID:
719 #endif
720 default:
721 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
722 goto error;
723 }
724
725 ret = LTTNG_OK;
726
727 error:
728 return ret;
729 }
730
731 /*
732 * Command LTTNG_ENABLE_CHANNEL processed by the client thread.
733 *
734 * The wpipe arguments is used as a notifier for the kernel thread.
735 */
736 int cmd_enable_channel(struct ltt_session *session,
737 int domain, struct lttng_channel *attr, int wpipe)
738 {
739 int ret;
740 struct ltt_ust_session *usess = session->ust_session;
741 struct lttng_ht *chan_ht;
742
743 assert(session);
744 assert(attr);
745
746 DBG("Enabling channel %s for session %s", attr->name, session->name);
747
748 switch (domain) {
749 case LTTNG_DOMAIN_KERNEL:
750 {
751 struct ltt_kernel_channel *kchan;
752
753 /* Mandatory for a kernel channel. */
754 assert(wpipe > 0);
755
756 kchan = trace_kernel_get_channel_by_name(attr->name,
757 session->kernel_session);
758 if (kchan == NULL) {
759 ret = channel_kernel_create(session->kernel_session, attr, wpipe);
760 } else {
761 ret = channel_kernel_enable(session->kernel_session, kchan);
762 }
763
764 if (ret != LTTNG_OK) {
765 goto error;
766 }
767
768 kernel_wait_quiescent(kernel_tracer_fd);
769 break;
770 }
771 case LTTNG_DOMAIN_UST:
772 {
773 struct ltt_ust_channel *uchan;
774
775 chan_ht = usess->domain_global.channels;
776
777 uchan = trace_ust_find_channel_by_name(chan_ht, attr->name);
778 if (uchan == NULL) {
779 ret = channel_ust_create(usess, domain, attr);
780 } else {
781 ret = channel_ust_enable(usess, domain, uchan);
782 }
783 break;
784 }
785 #if 0
786 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
787 case LTTNG_DOMAIN_UST_EXEC_NAME:
788 case LTTNG_DOMAIN_UST_PID:
789 #endif
790 default:
791 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
792 goto error;
793 }
794
795 error:
796 return ret;
797 }
798
799
800 /*
801 * Command LTTNG_DISABLE_EVENT processed by the client thread.
802 */
803 int cmd_disable_event(struct ltt_session *session, int domain,
804 char *channel_name, char *event_name)
805 {
806 int ret;
807
808 switch (domain) {
809 case LTTNG_DOMAIN_KERNEL:
810 {
811 struct ltt_kernel_channel *kchan;
812 struct ltt_kernel_session *ksess;
813
814 ksess = session->kernel_session;
815
816 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
817 if (kchan == NULL) {
818 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
819 goto error;
820 }
821
822 ret = event_kernel_disable_tracepoint(ksess, kchan, event_name);
823 if (ret != LTTNG_OK) {
824 goto error;
825 }
826
827 kernel_wait_quiescent(kernel_tracer_fd);
828 break;
829 }
830 case LTTNG_DOMAIN_UST:
831 {
832 struct ltt_ust_channel *uchan;
833 struct ltt_ust_session *usess;
834
835 usess = session->ust_session;
836
837 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
838 channel_name);
839 if (uchan == NULL) {
840 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
841 goto error;
842 }
843
844 ret = event_ust_disable_tracepoint(usess, domain, uchan, event_name);
845 if (ret != LTTNG_OK) {
846 goto error;
847 }
848
849 DBG3("Disable UST event %s in channel %s completed", event_name,
850 channel_name);
851 break;
852 }
853 #if 0
854 case LTTNG_DOMAIN_UST_EXEC_NAME:
855 case LTTNG_DOMAIN_UST_PID:
856 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
857 #endif
858 default:
859 ret = LTTNG_ERR_UND;
860 goto error;
861 }
862
863 ret = LTTNG_OK;
864
865 error:
866 return ret;
867 }
868
869 /*
870 * Command LTTNG_DISABLE_ALL_EVENT processed by the client thread.
871 */
872 int cmd_disable_event_all(struct ltt_session *session, int domain,
873 char *channel_name)
874 {
875 int ret;
876
877 switch (domain) {
878 case LTTNG_DOMAIN_KERNEL:
879 {
880 struct ltt_kernel_session *ksess;
881 struct ltt_kernel_channel *kchan;
882
883 ksess = session->kernel_session;
884
885 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
886 if (kchan == NULL) {
887 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
888 goto error;
889 }
890
891 ret = event_kernel_disable_all(ksess, kchan);
892 if (ret != LTTNG_OK) {
893 goto error;
894 }
895
896 kernel_wait_quiescent(kernel_tracer_fd);
897 break;
898 }
899 case LTTNG_DOMAIN_UST:
900 {
901 struct ltt_ust_session *usess;
902 struct ltt_ust_channel *uchan;
903
904 usess = session->ust_session;
905
906 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
907 channel_name);
908 if (uchan == NULL) {
909 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
910 goto error;
911 }
912
913 ret = event_ust_disable_all_tracepoints(usess, domain, uchan);
914 if (ret != 0) {
915 goto error;
916 }
917
918 DBG3("Disable all UST events in channel %s completed", channel_name);
919
920 break;
921 }
922 #if 0
923 case LTTNG_DOMAIN_UST_EXEC_NAME:
924 case LTTNG_DOMAIN_UST_PID:
925 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
926 #endif
927 default:
928 ret = LTTNG_ERR_UND;
929 goto error;
930 }
931
932 ret = LTTNG_OK;
933
934 error:
935 return ret;
936 }
937
938 /*
939 * Command LTTNG_ADD_CONTEXT processed by the client thread.
940 */
941 int cmd_add_context(struct ltt_session *session, int domain,
942 char *channel_name, char *event_name, struct lttng_event_context *ctx)
943 {
944 int ret;
945
946 switch (domain) {
947 case LTTNG_DOMAIN_KERNEL:
948 /* Add kernel context to kernel tracer */
949 ret = context_kernel_add(session->kernel_session, ctx,
950 event_name, channel_name);
951 if (ret != LTTNG_OK) {
952 goto error;
953 }
954 break;
955 case LTTNG_DOMAIN_UST:
956 {
957 struct ltt_ust_session *usess = session->ust_session;
958
959 assert(usess);
960
961 ret = context_ust_add(usess, domain, ctx, event_name, channel_name);
962 if (ret != LTTNG_OK) {
963 goto error;
964 }
965 break;
966 }
967 #if 0
968 case LTTNG_DOMAIN_UST_EXEC_NAME:
969 case LTTNG_DOMAIN_UST_PID:
970 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
971 #endif
972 default:
973 ret = LTTNG_ERR_UND;
974 goto error;
975 }
976
977 ret = LTTNG_OK;
978
979 error:
980 return ret;
981 }
982
983 /*
984 * Command LTTNG_SET_FILTER processed by the client thread.
985 */
986 int cmd_set_filter(struct ltt_session *session, int domain,
987 char *channel_name, char *event_name,
988 struct lttng_filter_bytecode *bytecode)
989 {
990 int ret;
991
992 switch (domain) {
993 case LTTNG_DOMAIN_KERNEL:
994 ret = LTTNG_ERR_FATAL;
995 break;
996 case LTTNG_DOMAIN_UST:
997 {
998 struct ltt_ust_session *usess = session->ust_session;
999
1000 ret = filter_ust_set(usess, domain, bytecode, event_name, channel_name);
1001 if (ret != LTTNG_OK) {
1002 goto error;
1003 }
1004 break;
1005 }
1006 #if 0
1007 case LTTNG_DOMAIN_UST_EXEC_NAME:
1008 case LTTNG_DOMAIN_UST_PID:
1009 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1010 #endif
1011 default:
1012 ret = LTTNG_ERR_UND;
1013 goto error;
1014 }
1015
1016 ret = LTTNG_OK;
1017
1018 error:
1019 return ret;
1020
1021 }
1022
1023
1024 /*
1025 * Command LTTNG_ENABLE_EVENT processed by the client thread.
1026 */
1027 int cmd_enable_event(struct ltt_session *session, int domain,
1028 char *channel_name, struct lttng_event *event, int wpipe)
1029 {
1030 int ret;
1031 struct lttng_channel *attr;
1032
1033 assert(session);
1034 assert(event);
1035 assert(channel_name);
1036
1037 switch (domain) {
1038 case LTTNG_DOMAIN_KERNEL:
1039 {
1040 struct ltt_kernel_channel *kchan;
1041
1042 kchan = trace_kernel_get_channel_by_name(channel_name,
1043 session->kernel_session);
1044 if (kchan == NULL) {
1045 attr = channel_new_default_attr(domain);
1046 if (attr == NULL) {
1047 ret = LTTNG_ERR_FATAL;
1048 goto error;
1049 }
1050 strncpy(attr->name, channel_name, sizeof(attr->name));
1051
1052 ret = cmd_enable_channel(session, domain, attr, wpipe);
1053 if (ret != LTTNG_OK) {
1054 free(attr);
1055 goto error;
1056 }
1057 free(attr);
1058 }
1059
1060 /* Get the newly created kernel channel pointer */
1061 kchan = trace_kernel_get_channel_by_name(channel_name,
1062 session->kernel_session);
1063 if (kchan == NULL) {
1064 /* This sould not happen... */
1065 ret = LTTNG_ERR_FATAL;
1066 goto error;
1067 }
1068
1069 ret = event_kernel_enable_tracepoint(session->kernel_session, kchan,
1070 event);
1071 if (ret != LTTNG_OK) {
1072 goto error;
1073 }
1074
1075 kernel_wait_quiescent(kernel_tracer_fd);
1076 break;
1077 }
1078 case LTTNG_DOMAIN_UST:
1079 {
1080 struct ltt_ust_channel *uchan;
1081 struct ltt_ust_session *usess = session->ust_session;
1082
1083 assert(usess);
1084
1085 /* Get channel from global UST domain */
1086 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1087 channel_name);
1088 if (uchan == NULL) {
1089 /* Create default channel */
1090 attr = channel_new_default_attr(domain);
1091 if (attr == NULL) {
1092 ret = LTTNG_ERR_FATAL;
1093 goto error;
1094 }
1095 strncpy(attr->name, channel_name, sizeof(attr->name));
1096
1097 ret = cmd_enable_channel(session, domain, attr, wpipe);
1098 if (ret != LTTNG_OK) {
1099 free(attr);
1100 goto error;
1101 }
1102 free(attr);
1103
1104 /* Get the newly created channel reference back */
1105 uchan = trace_ust_find_channel_by_name(
1106 usess->domain_global.channels, channel_name);
1107 assert(uchan);
1108 }
1109
1110 /* At this point, the session and channel exist on the tracer */
1111 ret = event_ust_enable_tracepoint(usess, domain, uchan, event);
1112 if (ret != LTTNG_OK) {
1113 goto error;
1114 }
1115 break;
1116 }
1117 #if 0
1118 case LTTNG_DOMAIN_UST_EXEC_NAME:
1119 case LTTNG_DOMAIN_UST_PID:
1120 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1121 #endif
1122 default:
1123 ret = LTTNG_ERR_UND;
1124 goto error;
1125 }
1126
1127 ret = LTTNG_OK;
1128
1129 error:
1130 return ret;
1131 }
1132
1133 /*
1134 * Command LTTNG_ENABLE_ALL_EVENT processed by the client thread.
1135 */
1136 int cmd_enable_event_all(struct ltt_session *session, int domain,
1137 char *channel_name, int event_type, int wpipe)
1138 {
1139 int ret;
1140 struct lttng_channel *attr;
1141
1142 assert(session);
1143 assert(channel_name);
1144
1145 switch (domain) {
1146 case LTTNG_DOMAIN_KERNEL:
1147 {
1148 struct ltt_kernel_channel *kchan;
1149
1150 assert(session->kernel_session);
1151
1152 kchan = trace_kernel_get_channel_by_name(channel_name,
1153 session->kernel_session);
1154 if (kchan == NULL) {
1155 /* Create default channel */
1156 attr = channel_new_default_attr(domain);
1157 if (attr == NULL) {
1158 ret = LTTNG_ERR_FATAL;
1159 goto error;
1160 }
1161 strncpy(attr->name, channel_name, sizeof(attr->name));
1162
1163 ret = cmd_enable_channel(session, domain, attr, wpipe);
1164 if (ret != LTTNG_OK) {
1165 free(attr);
1166 goto error;
1167 }
1168 free(attr);
1169
1170 /* Get the newly created kernel channel pointer */
1171 kchan = trace_kernel_get_channel_by_name(channel_name,
1172 session->kernel_session);
1173 assert(kchan);
1174 }
1175
1176 switch (event_type) {
1177 case LTTNG_EVENT_SYSCALL:
1178 ret = event_kernel_enable_all_syscalls(session->kernel_session,
1179 kchan, kernel_tracer_fd);
1180 break;
1181 case LTTNG_EVENT_TRACEPOINT:
1182 /*
1183 * This call enables all LTTNG_KERNEL_TRACEPOINTS and
1184 * events already registered to the channel.
1185 */
1186 ret = event_kernel_enable_all_tracepoints(session->kernel_session,
1187 kchan, kernel_tracer_fd);
1188 break;
1189 case LTTNG_EVENT_ALL:
1190 /* Enable syscalls and tracepoints */
1191 ret = event_kernel_enable_all(session->kernel_session,
1192 kchan, kernel_tracer_fd);
1193 break;
1194 default:
1195 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1196 goto error;
1197 }
1198
1199 /* Manage return value */
1200 if (ret != LTTNG_OK) {
1201 goto error;
1202 }
1203
1204 kernel_wait_quiescent(kernel_tracer_fd);
1205 break;
1206 }
1207 case LTTNG_DOMAIN_UST:
1208 {
1209 struct ltt_ust_channel *uchan;
1210 struct ltt_ust_session *usess = session->ust_session;
1211
1212 assert(usess);
1213
1214 /* Get channel from global UST domain */
1215 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1216 channel_name);
1217 if (uchan == NULL) {
1218 /* Create default channel */
1219 attr = channel_new_default_attr(domain);
1220 if (attr == NULL) {
1221 ret = LTTNG_ERR_FATAL;
1222 goto error;
1223 }
1224 strncpy(attr->name, channel_name, sizeof(attr->name));
1225
1226 ret = cmd_enable_channel(session, domain, attr, wpipe);
1227 if (ret != LTTNG_OK) {
1228 free(attr);
1229 goto error;
1230 }
1231 free(attr);
1232
1233 /* Get the newly created channel reference back */
1234 uchan = trace_ust_find_channel_by_name(
1235 usess->domain_global.channels, channel_name);
1236 assert(uchan);
1237 }
1238
1239 /* At this point, the session and channel exist on the tracer */
1240
1241 switch (event_type) {
1242 case LTTNG_EVENT_ALL:
1243 case LTTNG_EVENT_TRACEPOINT:
1244 ret = event_ust_enable_all_tracepoints(usess, domain, uchan);
1245 if (ret != LTTNG_OK) {
1246 goto error;
1247 }
1248 break;
1249 default:
1250 ret = LTTNG_ERR_UST_ENABLE_FAIL;
1251 goto error;
1252 }
1253
1254 /* Manage return value */
1255 if (ret != LTTNG_OK) {
1256 goto error;
1257 }
1258
1259 break;
1260 }
1261 #if 0
1262 case LTTNG_DOMAIN_UST_EXEC_NAME:
1263 case LTTNG_DOMAIN_UST_PID:
1264 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1265 #endif
1266 default:
1267 ret = LTTNG_ERR_UND;
1268 goto error;
1269 }
1270
1271 ret = LTTNG_OK;
1272
1273 error:
1274 return ret;
1275 }
1276
1277
1278 /*
1279 * Command LTTNG_LIST_TRACEPOINTS processed by the client thread.
1280 */
1281 ssize_t cmd_list_tracepoints(int domain, struct lttng_event **events)
1282 {
1283 int ret;
1284 ssize_t nb_events = 0;
1285
1286 switch (domain) {
1287 case LTTNG_DOMAIN_KERNEL:
1288 nb_events = kernel_list_events(kernel_tracer_fd, events);
1289 if (nb_events < 0) {
1290 ret = LTTNG_ERR_KERN_LIST_FAIL;
1291 goto error;
1292 }
1293 break;
1294 case LTTNG_DOMAIN_UST:
1295 nb_events = ust_app_list_events(events);
1296 if (nb_events < 0) {
1297 ret = LTTNG_ERR_UST_LIST_FAIL;
1298 goto error;
1299 }
1300 break;
1301 default:
1302 ret = LTTNG_ERR_UND;
1303 goto error;
1304 }
1305
1306 return nb_events;
1307
1308 error:
1309 /* Return negative value to differentiate return code */
1310 return -ret;
1311 }
1312
1313 /*
1314 * Command LTTNG_LIST_TRACEPOINT_FIELDS processed by the client thread.
1315 */
1316 ssize_t cmd_list_tracepoint_fields(int domain,
1317 struct lttng_event_field **fields)
1318 {
1319 int ret;
1320 ssize_t nb_fields = 0;
1321
1322 switch (domain) {
1323 case LTTNG_DOMAIN_UST:
1324 nb_fields = ust_app_list_event_fields(fields);
1325 if (nb_fields < 0) {
1326 ret = LTTNG_ERR_UST_LIST_FAIL;
1327 goto error;
1328 }
1329 break;
1330 case LTTNG_DOMAIN_KERNEL:
1331 default: /* fall-through */
1332 ret = LTTNG_ERR_UND;
1333 goto error;
1334 }
1335
1336 return nb_fields;
1337
1338 error:
1339 /* Return negative value to differentiate return code */
1340 return -ret;
1341 }
1342
1343 /*
1344 * Command LTTNG_START_TRACE processed by the client thread.
1345 */
1346 int cmd_start_trace(struct ltt_session *session)
1347 {
1348 int ret;
1349 struct ltt_kernel_session *ksession;
1350 struct ltt_ust_session *usess;
1351 struct ltt_kernel_channel *kchan;
1352
1353 assert(session);
1354
1355 /* Ease our life a bit ;) */
1356 ksession = session->kernel_session;
1357 usess = session->ust_session;
1358
1359 if (session->enabled) {
1360 /* Already started. */
1361 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
1362 goto error;
1363 }
1364
1365 session->enabled = 1;
1366
1367 ret = setup_relayd(session);
1368 if (ret != LTTNG_OK) {
1369 ERR("Error setting up relayd for session %s", session->name);
1370 goto error;
1371 }
1372
1373 /* Kernel tracing */
1374 if (ksession != NULL) {
1375 /* Open kernel metadata */
1376 if (ksession->metadata == NULL) {
1377 ret = kernel_open_metadata(ksession);
1378 if (ret < 0) {
1379 ret = LTTNG_ERR_KERN_META_FAIL;
1380 goto error;
1381 }
1382 }
1383
1384 /* Open kernel metadata stream */
1385 if (ksession->metadata_stream_fd < 0) {
1386 ret = kernel_open_metadata_stream(ksession);
1387 if (ret < 0) {
1388 ERR("Kernel create metadata stream failed");
1389 ret = LTTNG_ERR_KERN_STREAM_FAIL;
1390 goto error;
1391 }
1392 }
1393
1394 /* For each channel */
1395 cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
1396 if (kchan->stream_count == 0) {
1397 ret = kernel_open_channel_stream(kchan);
1398 if (ret < 0) {
1399 ret = LTTNG_ERR_KERN_STREAM_FAIL;
1400 goto error;
1401 }
1402 /* Update the stream global counter */
1403 ksession->stream_count_global += ret;
1404 }
1405 }
1406
1407 /* Setup kernel consumer socket and send fds to it */
1408 ret = init_kernel_tracing(ksession);
1409 if (ret < 0) {
1410 ret = LTTNG_ERR_KERN_START_FAIL;
1411 goto error;
1412 }
1413
1414 /* This start the kernel tracing */
1415 ret = kernel_start_session(ksession);
1416 if (ret < 0) {
1417 ret = LTTNG_ERR_KERN_START_FAIL;
1418 goto error;
1419 }
1420
1421 /* Quiescent wait after starting trace */
1422 kernel_wait_quiescent(kernel_tracer_fd);
1423 }
1424
1425 /* Flag session that trace should start automatically */
1426 if (usess) {
1427 usess->start_trace = 1;
1428
1429 ret = ust_app_start_trace_all(usess);
1430 if (ret < 0) {
1431 ret = LTTNG_ERR_UST_START_FAIL;
1432 goto error;
1433 }
1434 }
1435
1436 ret = LTTNG_OK;
1437
1438 error:
1439 return ret;
1440 }
1441
1442 /*
1443 * Command LTTNG_STOP_TRACE processed by the client thread.
1444 */
1445 int cmd_stop_trace(struct ltt_session *session)
1446 {
1447 int ret;
1448 struct ltt_kernel_channel *kchan;
1449 struct ltt_kernel_session *ksession;
1450 struct ltt_ust_session *usess;
1451
1452 assert(session);
1453
1454 /* Short cut */
1455 ksession = session->kernel_session;
1456 usess = session->ust_session;
1457
1458 if (!session->enabled) {
1459 ret = LTTNG_ERR_TRACE_ALREADY_STOPPED;
1460 goto error;
1461 }
1462
1463 session->enabled = 0;
1464
1465 /* Kernel tracer */
1466 if (ksession) {
1467 DBG("Stop kernel tracing");
1468
1469 /* Flush metadata if exist */
1470 if (ksession->metadata_stream_fd >= 0) {
1471 ret = kernel_metadata_flush_buffer(ksession->metadata_stream_fd);
1472 if (ret < 0) {
1473 ERR("Kernel metadata flush failed");
1474 }
1475 }
1476
1477 /* Flush all buffers before stopping */
1478 cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
1479 ret = kernel_flush_buffer(kchan);
1480 if (ret < 0) {
1481 ERR("Kernel flush buffer error");
1482 }
1483 }
1484
1485 ret = kernel_stop_session(ksession);
1486 if (ret < 0) {
1487 ret = LTTNG_ERR_KERN_STOP_FAIL;
1488 goto error;
1489 }
1490
1491 kernel_wait_quiescent(kernel_tracer_fd);
1492 }
1493
1494 if (usess) {
1495 usess->start_trace = 0;
1496
1497 ret = ust_app_stop_trace_all(usess);
1498 if (ret < 0) {
1499 ret = LTTNG_ERR_UST_STOP_FAIL;
1500 goto error;
1501 }
1502 }
1503
1504 ret = LTTNG_OK;
1505
1506 error:
1507 return ret;
1508 }
1509
1510 /*
1511 * Command LTTNG_SET_CONSUMER_URI processed by the client thread.
1512 */
1513 int cmd_set_consumer_uri(int domain, struct ltt_session *session,
1514 size_t nb_uri, struct lttng_uri *uris)
1515 {
1516 int ret, i;
1517 struct ltt_kernel_session *ksess = session->kernel_session;
1518 struct ltt_ust_session *usess = session->ust_session;
1519 struct consumer_output *consumer = NULL;
1520
1521 assert(session);
1522 assert(uris);
1523 assert(nb_uri > 0);
1524
1525 /* Can't enable consumer after session started. */
1526 if (session->enabled) {
1527 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
1528 goto error;
1529 }
1530
1531 if (!session->start_consumer) {
1532 ret = LTTNG_ERR_NO_CONSUMER;
1533 goto error;
1534 }
1535
1536 /*
1537 * This case switch makes sure the domain session has a temporary consumer
1538 * so the URL can be set.
1539 */
1540 switch (domain) {
1541 case 0:
1542 /* Code flow error. A session MUST always have a consumer object */
1543 assert(session->consumer);
1544 /*
1545 * The URL will be added to the tracing session consumer instead of a
1546 * specific domain consumer.
1547 */
1548 consumer = session->consumer;
1549 break;
1550 case LTTNG_DOMAIN_KERNEL:
1551 /* Code flow error if we don't have a kernel session here. */
1552 assert(ksess);
1553
1554 /* Create consumer output if none exists */
1555 consumer = ksess->tmp_consumer;
1556 if (consumer == NULL) {
1557 consumer = consumer_copy_output(ksess->consumer);
1558 if (consumer == NULL) {
1559 ret = LTTNG_ERR_FATAL;
1560 goto error;
1561 }
1562 /* Trash the consumer subdir, we are about to set a new one. */
1563 memset(consumer->subdir, 0, sizeof(consumer->subdir));
1564 ksess->tmp_consumer = consumer;
1565 }
1566
1567 break;
1568 case LTTNG_DOMAIN_UST:
1569 /* Code flow error if we don't have a kernel session here. */
1570 assert(usess);
1571
1572 /* Create consumer output if none exists */
1573 consumer = usess->tmp_consumer;
1574 if (consumer == NULL) {
1575 consumer = consumer_copy_output(usess->consumer);
1576 if (consumer == NULL) {
1577 ret = LTTNG_ERR_FATAL;
1578 goto error;
1579 }
1580 /* Trash the consumer subdir, we are about to set a new one. */
1581 memset(consumer->subdir, 0, sizeof(consumer->subdir));
1582 usess->tmp_consumer = consumer;
1583 }
1584
1585 break;
1586 }
1587
1588 for (i = 0; i < nb_uri; i++) {
1589 struct consumer_socket *socket;
1590 struct lttng_ht_iter iter;
1591
1592 ret = add_uri_to_consumer(consumer, &uris[i], domain, session->name);
1593 if (ret < 0) {
1594 goto error;
1595 }
1596
1597 /*
1598 * Don't send relayd socket if URI is NOT remote or if the relayd
1599 * socket for the session was already sent.
1600 */
1601 if (uris[i].dtype == LTTNG_DST_PATH ||
1602 (uris[i].stype == LTTNG_STREAM_CONTROL &&
1603 consumer->dst.net.control_sock_sent) ||
1604 (uris[i].stype == LTTNG_STREAM_DATA &&
1605 consumer->dst.net.data_sock_sent)) {
1606 continue;
1607 }
1608
1609 /* Try to send relayd URI to the consumer if exist. */
1610 rcu_read_lock();
1611 cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter,
1612 socket, node.node) {
1613
1614 /* A socket in the HT should never have a negative fd */
1615 assert(socket->fd >= 0);
1616
1617 pthread_mutex_lock(socket->lock);
1618 ret = send_consumer_relayd_socket(domain, session, &uris[i],
1619 consumer, socket->fd);
1620 pthread_mutex_unlock(socket->lock);
1621 if (ret != LTTNG_OK) {
1622 rcu_read_unlock();
1623 goto error;
1624 }
1625 }
1626 rcu_read_unlock();
1627 }
1628
1629 /* All good! */
1630 ret = LTTNG_OK;
1631
1632 error:
1633 return ret;
1634 }
1635
1636 /*
1637 * Command LTTNG_CREATE_SESSION processed by the client thread.
1638 */
1639 int cmd_create_session_uri(char *name, struct lttng_uri *uris,
1640 size_t nb_uri, lttng_sock_cred *creds)
1641 {
1642 int ret;
1643 char *path = NULL;
1644 struct ltt_session *session;
1645
1646 assert(name);
1647
1648 /*
1649 * Verify if the session already exist
1650 *
1651 * XXX: There is no need for the session lock list here since the caller
1652 * (process_client_msg) is holding it. We might want to change that so a
1653 * single command does not lock the entire session list.
1654 */
1655 session = session_find_by_name(name);
1656 if (session != NULL) {
1657 ret = LTTNG_ERR_EXIST_SESS;
1658 goto find_error;
1659 }
1660
1661 /* Create tracing session in the registry */
1662 ret = session_create(name, path, LTTNG_SOCK_GET_UID_CRED(creds),
1663 LTTNG_SOCK_GET_GID_CRED(creds));
1664 if (ret != LTTNG_OK) {
1665 goto session_error;
1666 }
1667
1668 /*
1669 * Get the newly created session pointer back
1670 *
1671 * XXX: There is no need for the session lock list here since the caller
1672 * (process_client_msg) is holding it. We might want to change that so a
1673 * single command does not lock the entire session list.
1674 */
1675 session = session_find_by_name(name);
1676 assert(session);
1677
1678 /* Create default consumer output for the session not yet created. */
1679 session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
1680 if (session->consumer == NULL) {
1681 ret = LTTNG_ERR_FATAL;
1682 goto consumer_error;
1683 }
1684
1685 /*
1686 * This means that the lttng_create_session call was called with the _path_
1687 * argument set to NULL.
1688 */
1689 if (uris == NULL) {
1690 /*
1691 * At this point, we'll skip the consumer URI setup and create a
1692 * session with a NULL path which will flag the session to NOT spawn a
1693 * consumer.
1694 */
1695 DBG("Create session %s with NO uri, skipping consumer setup", name);
1696 goto end;
1697 }
1698
1699 session->start_consumer = 1;
1700
1701 ret = cmd_set_consumer_uri(0, session, nb_uri, uris);
1702 if (ret != LTTNG_OK) {
1703 goto consumer_error;
1704 }
1705
1706 session->consumer->enabled = 1;
1707
1708 end:
1709 return LTTNG_OK;
1710
1711 consumer_error:
1712 session_destroy(session);
1713 session_error:
1714 find_error:
1715 return ret;
1716 }
1717
1718 /*
1719 * Command LTTNG_DESTROY_SESSION processed by the client thread.
1720 */
1721 int cmd_destroy_session(struct ltt_session *session, int wpipe)
1722 {
1723 int ret;
1724 struct ltt_ust_session *usess;
1725 struct ltt_kernel_session *ksess;
1726
1727 /* Safety net */
1728 assert(session);
1729
1730 usess = session->ust_session;
1731 ksess = session->kernel_session;
1732
1733 /* Clean kernel session teardown */
1734 kernel_destroy_session(ksess);
1735
1736 /* UST session teardown */
1737 if (usess) {
1738 /* Close any relayd session */
1739 consumer_output_send_destroy_relayd(usess->consumer);
1740
1741 /* Destroy every UST application related to this session. */
1742 ret = ust_app_destroy_trace_all(usess);
1743 if (ret) {
1744 ERR("Error in ust_app_destroy_trace_all");
1745 }
1746
1747 /* Clean up the rest. */
1748 trace_ust_destroy_session(usess);
1749 }
1750
1751 /*
1752 * Must notify the kernel thread here to update it's poll set in order to
1753 * remove the channel(s)' fd just destroyed.
1754 */
1755 ret = notify_thread_pipe(wpipe);
1756 if (ret < 0) {
1757 PERROR("write kernel poll pipe");
1758 }
1759
1760 ret = session_destroy(session);
1761
1762 return ret;
1763 }
1764
1765 /*
1766 * Command LTTNG_CALIBRATE processed by the client thread.
1767 */
1768 int cmd_calibrate(int domain, struct lttng_calibrate *calibrate)
1769 {
1770 int ret;
1771
1772 switch (domain) {
1773 case LTTNG_DOMAIN_KERNEL:
1774 {
1775 struct lttng_kernel_calibrate kcalibrate;
1776
1777 kcalibrate.type = calibrate->type;
1778 ret = kernel_calibrate(kernel_tracer_fd, &kcalibrate);
1779 if (ret < 0) {
1780 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1781 goto error;
1782 }
1783 break;
1784 }
1785 case LTTNG_DOMAIN_UST:
1786 {
1787 struct lttng_ust_calibrate ucalibrate;
1788
1789 ucalibrate.type = calibrate->type;
1790 ret = ust_app_calibrate_glb(&ucalibrate);
1791 if (ret < 0) {
1792 ret = LTTNG_ERR_UST_CALIBRATE_FAIL;
1793 goto error;
1794 }
1795 break;
1796 }
1797 default:
1798 ret = LTTNG_ERR_UND;
1799 goto error;
1800 }
1801
1802 ret = LTTNG_OK;
1803
1804 error:
1805 return ret;
1806 }
1807
1808 /*
1809 * Command LTTNG_REGISTER_CONSUMER processed by the client thread.
1810 */
1811 int cmd_register_consumer(struct ltt_session *session, int domain,
1812 const char *sock_path, struct consumer_data *cdata)
1813 {
1814 int ret, sock;
1815 struct consumer_socket *socket;
1816
1817 assert(session);
1818 assert(cdata);
1819 assert(sock_path);
1820
1821 switch (domain) {
1822 case LTTNG_DOMAIN_KERNEL:
1823 {
1824 struct ltt_kernel_session *ksess = session->kernel_session;
1825
1826 assert(ksess);
1827
1828 /* Can't register a consumer if there is already one */
1829 if (ksess->consumer_fds_sent != 0) {
1830 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
1831 goto error;
1832 }
1833
1834 sock = lttcomm_connect_unix_sock(sock_path);
1835 if (sock < 0) {
1836 ret = LTTNG_ERR_CONNECT_FAIL;
1837 goto error;
1838 }
1839
1840 socket = consumer_allocate_socket(sock);
1841 if (socket == NULL) {
1842 ret = LTTNG_ERR_FATAL;
1843 close(sock);
1844 goto error;
1845 }
1846
1847 socket->lock = zmalloc(sizeof(pthread_mutex_t));
1848 if (socket->lock == NULL) {
1849 PERROR("zmalloc pthread mutex");
1850 ret = LTTNG_ERR_FATAL;
1851 goto error;
1852 }
1853 pthread_mutex_init(socket->lock, NULL);
1854 socket->registered = 1;
1855
1856 rcu_read_lock();
1857 consumer_add_socket(socket, ksess->consumer);
1858 rcu_read_unlock();
1859
1860 pthread_mutex_lock(&cdata->pid_mutex);
1861 cdata->pid = -1;
1862 pthread_mutex_unlock(&cdata->pid_mutex);
1863
1864 break;
1865 }
1866 default:
1867 /* TODO: Userspace tracing */
1868 ret = LTTNG_ERR_UND;
1869 goto error;
1870 }
1871
1872 ret = LTTNG_OK;
1873
1874 error:
1875 return ret;
1876 }
1877
1878 /*
1879 * Command LTTNG_LIST_DOMAINS processed by the client thread.
1880 */
1881 ssize_t cmd_list_domains(struct ltt_session *session,
1882 struct lttng_domain **domains)
1883 {
1884 int ret, index = 0;
1885 ssize_t nb_dom = 0;
1886
1887 if (session->kernel_session != NULL) {
1888 DBG3("Listing domains found kernel domain");
1889 nb_dom++;
1890 }
1891
1892 if (session->ust_session != NULL) {
1893 DBG3("Listing domains found UST global domain");
1894 nb_dom++;
1895 }
1896
1897 *domains = zmalloc(nb_dom * sizeof(struct lttng_domain));
1898 if (*domains == NULL) {
1899 ret = LTTNG_ERR_FATAL;
1900 goto error;
1901 }
1902
1903 if (session->kernel_session != NULL) {
1904 (*domains)[index].type = LTTNG_DOMAIN_KERNEL;
1905 index++;
1906 }
1907
1908 if (session->ust_session != NULL) {
1909 (*domains)[index].type = LTTNG_DOMAIN_UST;
1910 index++;
1911 }
1912
1913 return nb_dom;
1914
1915 error:
1916 /* Return negative value to differentiate return code */
1917 return -ret;
1918 }
1919
1920
1921 /*
1922 * Command LTTNG_LIST_CHANNELS processed by the client thread.
1923 */
1924 ssize_t cmd_list_channels(int domain, struct ltt_session *session,
1925 struct lttng_channel **channels)
1926 {
1927 int ret;
1928 ssize_t nb_chan = 0;
1929
1930 switch (domain) {
1931 case LTTNG_DOMAIN_KERNEL:
1932 if (session->kernel_session != NULL) {
1933 nb_chan = session->kernel_session->channel_count;
1934 }
1935 DBG3("Number of kernel channels %zd", nb_chan);
1936 if (nb_chan <= 0) {
1937 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
1938 }
1939 break;
1940 case LTTNG_DOMAIN_UST:
1941 if (session->ust_session != NULL) {
1942 nb_chan = lttng_ht_get_count(
1943 session->ust_session->domain_global.channels);
1944 }
1945 DBG3("Number of UST global channels %zd", nb_chan);
1946 if (nb_chan <= 0) {
1947 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1948 }
1949 break;
1950 default:
1951 *channels = NULL;
1952 ret = LTTNG_ERR_UND;
1953 goto error;
1954 }
1955
1956 if (nb_chan > 0) {
1957 *channels = zmalloc(nb_chan * sizeof(struct lttng_channel));
1958 if (*channels == NULL) {
1959 ret = LTTNG_ERR_FATAL;
1960 goto error;
1961 }
1962
1963 list_lttng_channels(domain, session, *channels);
1964 } else {
1965 *channels = NULL;
1966 /* Ret value was set in the domain switch case */
1967 goto error;
1968 }
1969
1970 return nb_chan;
1971
1972 error:
1973 /* Return negative value to differentiate return code */
1974 return -ret;
1975 }
1976
1977 /*
1978 * Command LTTNG_LIST_EVENTS processed by the client thread.
1979 */
1980 ssize_t cmd_list_events(int domain, struct ltt_session *session,
1981 char *channel_name, struct lttng_event **events)
1982 {
1983 int ret = 0;
1984 ssize_t nb_event = 0;
1985
1986 switch (domain) {
1987 case LTTNG_DOMAIN_KERNEL:
1988 if (session->kernel_session != NULL) {
1989 nb_event = list_lttng_kernel_events(channel_name,
1990 session->kernel_session, events);
1991 }
1992 break;
1993 case LTTNG_DOMAIN_UST:
1994 {
1995 if (session->ust_session != NULL) {
1996 nb_event = list_lttng_ust_global_events(channel_name,
1997 &session->ust_session->domain_global, events);
1998 }
1999 break;
2000 }
2001 default:
2002 ret = LTTNG_ERR_UND;
2003 goto error;
2004 }
2005
2006 return nb_event;
2007
2008 error:
2009 /* Return negative value to differentiate return code */
2010 return -ret;
2011 }
2012
2013 /*
2014 * Using the session list, filled a lttng_session array to send back to the
2015 * client for session listing.
2016 *
2017 * The session list lock MUST be acquired before calling this function. Use
2018 * session_lock_list() and session_unlock_list().
2019 */
2020 void cmd_list_lttng_sessions(struct lttng_session *sessions, uid_t uid,
2021 gid_t gid)
2022 {
2023 int ret;
2024 unsigned int i = 0;
2025 struct ltt_session *session;
2026 struct ltt_session_list *list = session_get_list();
2027
2028 DBG("Getting all available session for UID %d GID %d",
2029 uid, gid);
2030 /*
2031 * Iterate over session list and append data after the control struct in
2032 * the buffer.
2033 */
2034 cds_list_for_each_entry(session, &list->head, list) {
2035 /*
2036 * Only list the sessions the user can control.
2037 */
2038 if (!session_access_ok(session, uid, gid)) {
2039 continue;
2040 }
2041
2042 struct ltt_kernel_session *ksess = session->kernel_session;
2043 struct ltt_ust_session *usess = session->ust_session;
2044
2045 if (session->consumer->type == CONSUMER_DST_NET ||
2046 (ksess && ksess->consumer->type == CONSUMER_DST_NET) ||
2047 (usess && usess->consumer->type == CONSUMER_DST_NET)) {
2048 ret = build_network_session_path(sessions[i].path,
2049 sizeof(session[i].path), session);
2050 } else {
2051 ret = snprintf(sessions[i].path, sizeof(session[i].path), "%s",
2052 session->consumer->dst.trace_path);
2053 }
2054 if (ret < 0) {
2055 PERROR("snprintf session path");
2056 continue;
2057 }
2058
2059 strncpy(sessions[i].name, session->name, NAME_MAX);
2060 sessions[i].name[NAME_MAX - 1] = '\0';
2061 sessions[i].enabled = session->enabled;
2062 i++;
2063 }
2064 }
2065
2066 /*
2067 * Command LTTNG_DISABLE_CONSUMER processed by the client thread.
2068 */
2069 int cmd_disable_consumer(int domain, struct ltt_session *session)
2070 {
2071 int ret;
2072 struct ltt_kernel_session *ksess = session->kernel_session;
2073 struct ltt_ust_session *usess = session->ust_session;
2074 struct consumer_output *consumer;
2075
2076 assert(session);
2077
2078 if (session->enabled) {
2079 /* Can't disable consumer on an already started session */
2080 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2081 goto error;
2082 }
2083
2084 if (!session->start_consumer) {
2085 ret = LTTNG_ERR_NO_CONSUMER;
2086 goto error;
2087 }
2088
2089 switch (domain) {
2090 case 0:
2091 DBG("Disable tracing session %s consumer", session->name);
2092 consumer = session->consumer;
2093 break;
2094 case LTTNG_DOMAIN_KERNEL:
2095 /* Code flow error if we don't have a kernel session here. */
2096 assert(ksess);
2097
2098 DBG("Disabling kernel consumer");
2099 consumer = ksess->consumer;
2100
2101 break;
2102 case LTTNG_DOMAIN_UST:
2103 /* Code flow error if we don't have a UST session here. */
2104 assert(usess);
2105
2106 DBG("Disabling UST consumer");
2107 consumer = usess->consumer;
2108
2109 break;
2110 default:
2111 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
2112 goto error;
2113 }
2114
2115 if (consumer) {
2116 consumer->enabled = 0;
2117 /* Success at this point */
2118 ret = LTTNG_OK;
2119 } else {
2120 ret = LTTNG_ERR_NO_CONSUMER;
2121 }
2122
2123 error:
2124 return ret;
2125 }
2126
2127 /*
2128 * Command LTTNG_ENABLE_CONSUMER processed by the client thread.
2129 */
2130 int cmd_enable_consumer(int domain, struct ltt_session *session)
2131 {
2132 int ret;
2133 struct ltt_kernel_session *ksess = session->kernel_session;
2134 struct ltt_ust_session *usess = session->ust_session;
2135 struct consumer_output *consumer = NULL;
2136
2137 assert(session);
2138
2139 /* Can't enable consumer after session started. */
2140 if (session->enabled) {
2141 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2142 goto error;
2143 }
2144
2145 if (!session->start_consumer) {
2146 ret = LTTNG_ERR_NO_CONSUMER;
2147 goto error;
2148 }
2149
2150 switch (domain) {
2151 case 0:
2152 assert(session->consumer);
2153 consumer = session->consumer;
2154 break;
2155 case LTTNG_DOMAIN_KERNEL:
2156 /* Code flow error if we don't have a kernel session here. */
2157 assert(ksess);
2158
2159 /*
2160 * Check if we have already sent fds to the consumer. In that case,
2161 * the enable-consumer command can't be used because a start trace
2162 * had previously occured.
2163 */
2164 if (ksess->consumer_fds_sent) {
2165 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2166 goto error;
2167 }
2168
2169 consumer = ksess->tmp_consumer;
2170 if (consumer == NULL) {
2171 ret = LTTNG_OK;
2172 /* No temp. consumer output exists. Using the current one. */
2173 DBG3("No temporary consumer. Using default");
2174 consumer = ksess->consumer;
2175 goto error;
2176 }
2177
2178 switch (consumer->type) {
2179 case CONSUMER_DST_LOCAL:
2180 DBG2("Consumer output is local. Creating directory(ies)");
2181
2182 /* Create directory(ies) */
2183 ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2184 S_IRWXU | S_IRWXG, session->uid, session->gid);
2185 if (ret < 0) {
2186 if (ret != -EEXIST) {
2187 ERR("Trace directory creation error");
2188 ret = LTTNG_ERR_FATAL;
2189 goto error;
2190 }
2191 }
2192 break;
2193 case CONSUMER_DST_NET:
2194 DBG2("Consumer output is network. Validating URIs");
2195 /* Validate if we have both control and data path set. */
2196 if (!consumer->dst.net.control_isset) {
2197 ret = LTTNG_ERR_URL_CTRL_MISS;
2198 goto error;
2199 }
2200
2201 if (!consumer->dst.net.data_isset) {
2202 ret = LTTNG_ERR_URL_DATA_MISS;
2203 goto error;
2204 }
2205
2206 /* Check established network session state */
2207 if (session->net_handle == 0) {
2208 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2209 ERR("Session network handle is not set on enable-consumer");
2210 goto error;
2211 }
2212
2213 break;
2214 }
2215
2216 /* Append default kernel trace dir to subdir */
2217 strncat(ksess->consumer->subdir, DEFAULT_KERNEL_TRACE_DIR,
2218 sizeof(ksess->consumer->subdir) -
2219 strlen(ksess->consumer->subdir) - 1);
2220
2221 /*
2222 * @session-lock
2223 * This is race free for now since the session lock is acquired before
2224 * ending up in this function. No other threads can access this kernel
2225 * session without this lock hence freeing the consumer output object
2226 * is valid.
2227 */
2228 rcu_read_lock();
2229 consumer_destroy_output(ksess->consumer);
2230 rcu_read_unlock();
2231 ksess->consumer = consumer;
2232 ksess->tmp_consumer = NULL;
2233
2234 break;
2235 case LTTNG_DOMAIN_UST:
2236 /* Code flow error if we don't have a UST session here. */
2237 assert(usess);
2238
2239 /*
2240 * Check if we have already sent fds to the consumer. In that case,
2241 * the enable-consumer command can't be used because a start trace
2242 * had previously occured.
2243 */
2244 if (usess->start_trace) {
2245 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2246 goto error;
2247 }
2248
2249 consumer = usess->tmp_consumer;
2250 if (consumer == NULL) {
2251 ret = LTTNG_OK;
2252 /* No temp. consumer output exists. Using the current one. */
2253 DBG3("No temporary consumer. Using default");
2254 consumer = usess->consumer;
2255 goto error;
2256 }
2257
2258 switch (consumer->type) {
2259 case CONSUMER_DST_LOCAL:
2260 DBG2("Consumer output is local. Creating directory(ies)");
2261
2262 /* Create directory(ies) */
2263 ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2264 S_IRWXU | S_IRWXG, session->uid, session->gid);
2265 if (ret < 0) {
2266 if (ret != -EEXIST) {
2267 ERR("Trace directory creation error");
2268 ret = LTTNG_ERR_FATAL;
2269 goto error;
2270 }
2271 }
2272 break;
2273 case CONSUMER_DST_NET:
2274 DBG2("Consumer output is network. Validating URIs");
2275 /* Validate if we have both control and data path set. */
2276 if (!consumer->dst.net.control_isset) {
2277 ret = LTTNG_ERR_URL_CTRL_MISS;
2278 goto error;
2279 }
2280
2281 if (!consumer->dst.net.data_isset) {
2282 ret = LTTNG_ERR_URL_DATA_MISS;
2283 goto error;
2284 }
2285
2286 /* Check established network session state */
2287 if (session->net_handle == 0) {
2288 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2289 DBG2("Session network handle is not set on enable-consumer");
2290 goto error;
2291 }
2292
2293 if (consumer->net_seq_index == -1) {
2294 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2295 DBG2("Network index is not set on the consumer");
2296 goto error;
2297 }
2298
2299 break;
2300 }
2301
2302 /* Append default kernel trace dir to subdir */
2303 strncat(usess->consumer->subdir, DEFAULT_UST_TRACE_DIR,
2304 sizeof(usess->consumer->subdir) -
2305 strlen(usess->consumer->subdir) - 1);
2306
2307 /*
2308 * @session-lock
2309 * This is race free for now since the session lock is acquired before
2310 * ending up in this function. No other threads can access this kernel
2311 * session without this lock hence freeing the consumer output object
2312 * is valid.
2313 */
2314 rcu_read_lock();
2315 consumer_destroy_output(usess->consumer);
2316 rcu_read_unlock();
2317 usess->consumer = consumer;
2318 usess->tmp_consumer = NULL;
2319
2320 break;
2321 }
2322
2323 /* Enable it */
2324 if (consumer) {
2325 consumer->enabled = 1;
2326 /* Success at this point */
2327 ret = LTTNG_OK;
2328 } else {
2329 /* Should not really happend... */
2330 ret = LTTNG_ERR_NO_CONSUMER;
2331 }
2332
2333 error:
2334 return ret;
2335 }
2336
2337 /*
2338 * Command LTTNG_DATA_AVAILABLE returning 0 if the data is NOT ready to be read
2339 * or else 1 if the data is available for trace analysis.
2340 */
2341 int cmd_data_available(struct ltt_session *session)
2342 {
2343 int ret;
2344 struct ltt_kernel_session *ksess = session->kernel_session;
2345 struct ltt_ust_session *usess = session->ust_session;
2346
2347 assert(session);
2348
2349 /* Session MUST be stopped to ask for data availability. */
2350 if (session->enabled) {
2351 ret = LTTNG_ERR_SESSION_STARTED;
2352 goto error;
2353 }
2354
2355 if (ksess && ksess->consumer) {
2356 ret = consumer_is_data_available(ksess->id, ksess->consumer);
2357 if (ret == 0) {
2358 /* Data is still being extracted for the kernel. */
2359 goto error;
2360 }
2361 }
2362
2363 if (usess && usess->consumer) {
2364 ret = consumer_is_data_available(usess->id, usess->consumer);
2365 if (ret == 0) {
2366 /* Data is still being extracted for the kernel. */
2367 goto error;
2368 }
2369 }
2370
2371 /* Data is ready to be read by a viewer */
2372 ret = 1;
2373
2374 error:
2375 return ret;
2376 }
2377
2378 /*
2379 * Init command subsystem.
2380 */
2381 void cmd_init(void)
2382 {
2383 /*
2384 * Set network sequence index to 1 for streams to match a relayd socket on
2385 * the consumer side.
2386 */
2387 uatomic_set(&relayd_net_seq_idx, 1);
2388
2389 DBG("Command subsystem initialized");
2390 }
LTTng 2.0 tools and control repository
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