c561b9bd2c935e5e275972aa8c8b9965b950671b
[lttng-tools.git] / src / common / consumer.c
1 /*
2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 * 2012 - David Goulet <dgoulet@efficios.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License, version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #define _GNU_SOURCE
21 #include <assert.h>
22 #include <poll.h>
23 #include <pthread.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <sys/mman.h>
27 #include <sys/socket.h>
28 #include <sys/types.h>
29 #include <unistd.h>
30 #include <inttypes.h>
31
32 #include <common/common.h>
33 #include <common/utils.h>
34 #include <common/compat/poll.h>
35 #include <common/kernel-ctl/kernel-ctl.h>
36 #include <common/sessiond-comm/relayd.h>
37 #include <common/sessiond-comm/sessiond-comm.h>
38 #include <common/kernel-consumer/kernel-consumer.h>
39 #include <common/relayd/relayd.h>
40 #include <common/ust-consumer/ust-consumer.h>
41
42 #include "consumer.h"
43
44 struct lttng_consumer_global_data consumer_data = {
45 .stream_count = 0,
46 .need_update = 1,
47 .type = LTTNG_CONSUMER_UNKNOWN,
48 };
49
50 /*
51 * Flag to inform the polling thread to quit when all fd hung up. Updated by
52 * the consumer_thread_receive_fds when it notices that all fds has hung up.
53 * Also updated by the signal handler (consumer_should_exit()). Read by the
54 * polling threads.
55 */
56 volatile int consumer_quit;
57
58 /*
59 * Global hash table containing respectively metadata and data streams. The
60 * stream element in this ht should only be updated by the metadata poll thread
61 * for the metadata and the data poll thread for the data.
62 */
63 static struct lttng_ht *metadata_ht;
64 static struct lttng_ht *data_ht;
65
66 /*
67 * Notify a thread pipe to poll back again. This usually means that some global
68 * state has changed so we just send back the thread in a poll wait call.
69 */
70 static void notify_thread_pipe(int wpipe)
71 {
72 int ret;
73
74 do {
75 struct lttng_consumer_stream *null_stream = NULL;
76
77 ret = write(wpipe, &null_stream, sizeof(null_stream));
78 } while (ret < 0 && errno == EINTR);
79 }
80
81 /*
82 * Find a stream. The consumer_data.lock must be locked during this
83 * call.
84 */
85 static struct lttng_consumer_stream *consumer_find_stream(int key,
86 struct lttng_ht *ht)
87 {
88 struct lttng_ht_iter iter;
89 struct lttng_ht_node_ulong *node;
90 struct lttng_consumer_stream *stream = NULL;
91
92 assert(ht);
93
94 /* Negative keys are lookup failures */
95 if (key < 0) {
96 return NULL;
97 }
98
99 rcu_read_lock();
100
101 lttng_ht_lookup(ht, (void *)((unsigned long) key), &iter);
102 node = lttng_ht_iter_get_node_ulong(&iter);
103 if (node != NULL) {
104 stream = caa_container_of(node, struct lttng_consumer_stream, node);
105 }
106
107 rcu_read_unlock();
108
109 return stream;
110 }
111
112 void consumer_steal_stream_key(int key, struct lttng_ht *ht)
113 {
114 struct lttng_consumer_stream *stream;
115
116 rcu_read_lock();
117 stream = consumer_find_stream(key, ht);
118 if (stream) {
119 stream->key = -1;
120 /*
121 * We don't want the lookup to match, but we still need
122 * to iterate on this stream when iterating over the hash table. Just
123 * change the node key.
124 */
125 stream->node.key = -1;
126 }
127 rcu_read_unlock();
128 }
129
130 /*
131 * Return a channel object for the given key.
132 *
133 * RCU read side lock MUST be acquired before calling this function and
134 * protects the channel ptr.
135 */
136 static struct lttng_consumer_channel *consumer_find_channel(int key)
137 {
138 struct lttng_ht_iter iter;
139 struct lttng_ht_node_ulong *node;
140 struct lttng_consumer_channel *channel = NULL;
141
142 /* Negative keys are lookup failures */
143 if (key < 0) {
144 return NULL;
145 }
146
147 lttng_ht_lookup(consumer_data.channel_ht, (void *)((unsigned long) key),
148 &iter);
149 node = lttng_ht_iter_get_node_ulong(&iter);
150 if (node != NULL) {
151 channel = caa_container_of(node, struct lttng_consumer_channel, node);
152 }
153
154 return channel;
155 }
156
157 static void consumer_steal_channel_key(int key)
158 {
159 struct lttng_consumer_channel *channel;
160
161 rcu_read_lock();
162 channel = consumer_find_channel(key);
163 if (channel) {
164 channel->key = -1;
165 /*
166 * We don't want the lookup to match, but we still need
167 * to iterate on this channel when iterating over the hash table. Just
168 * change the node key.
169 */
170 channel->node.key = -1;
171 }
172 rcu_read_unlock();
173 }
174
175 static
176 void consumer_free_stream(struct rcu_head *head)
177 {
178 struct lttng_ht_node_ulong *node =
179 caa_container_of(head, struct lttng_ht_node_ulong, head);
180 struct lttng_consumer_stream *stream =
181 caa_container_of(node, struct lttng_consumer_stream, node);
182
183 free(stream);
184 }
185
186 /*
187 * RCU protected relayd socket pair free.
188 */
189 static void consumer_rcu_free_relayd(struct rcu_head *head)
190 {
191 struct lttng_ht_node_ulong *node =
192 caa_container_of(head, struct lttng_ht_node_ulong, head);
193 struct consumer_relayd_sock_pair *relayd =
194 caa_container_of(node, struct consumer_relayd_sock_pair, node);
195
196 /*
197 * Close all sockets. This is done in the call RCU since we don't want the
198 * socket fds to be reassigned thus potentially creating bad state of the
199 * relayd object.
200 *
201 * We do not have to lock the control socket mutex here since at this stage
202 * there is no one referencing to this relayd object.
203 */
204 (void) relayd_close(&relayd->control_sock);
205 (void) relayd_close(&relayd->data_sock);
206
207 free(relayd);
208 }
209
210 /*
211 * Destroy and free relayd socket pair object.
212 *
213 * This function MUST be called with the consumer_data lock acquired.
214 */
215 static void destroy_relayd(struct consumer_relayd_sock_pair *relayd)
216 {
217 int ret;
218 struct lttng_ht_iter iter;
219
220 if (relayd == NULL) {
221 return;
222 }
223
224 DBG("Consumer destroy and close relayd socket pair");
225
226 iter.iter.node = &relayd->node.node;
227 ret = lttng_ht_del(consumer_data.relayd_ht, &iter);
228 if (ret != 0) {
229 /* We assume the relayd is being or is destroyed */
230 return;
231 }
232
233 /* RCU free() call */
234 call_rcu(&relayd->node.head, consumer_rcu_free_relayd);
235 }
236
237 /*
238 * Update the end point status of all streams having the given network sequence
239 * index (relayd index).
240 *
241 * It's atomically set without having the stream mutex locked which is fine
242 * because we handle the write/read race with a pipe wakeup for each thread.
243 */
244 static void update_endpoint_status_by_netidx(int net_seq_idx,
245 enum consumer_endpoint_status status)
246 {
247 struct lttng_ht_iter iter;
248 struct lttng_consumer_stream *stream;
249
250 DBG("Consumer set delete flag on stream by idx %d", net_seq_idx);
251
252 rcu_read_lock();
253
254 /* Let's begin with metadata */
255 cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) {
256 if (stream->net_seq_idx == net_seq_idx) {
257 uatomic_set(&stream->endpoint_status, status);
258 DBG("Delete flag set to metadata stream %d", stream->wait_fd);
259 }
260 }
261
262 /* Follow up by the data streams */
263 cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) {
264 if (stream->net_seq_idx == net_seq_idx) {
265 uatomic_set(&stream->endpoint_status, status);
266 DBG("Delete flag set to data stream %d", stream->wait_fd);
267 }
268 }
269 rcu_read_unlock();
270 }
271
272 /*
273 * Cleanup a relayd object by flagging every associated streams for deletion,
274 * destroying the object meaning removing it from the relayd hash table,
275 * closing the sockets and freeing the memory in a RCU call.
276 *
277 * If a local data context is available, notify the threads that the streams'
278 * state have changed.
279 */
280 static void cleanup_relayd(struct consumer_relayd_sock_pair *relayd,
281 struct lttng_consumer_local_data *ctx)
282 {
283 int netidx;
284
285 assert(relayd);
286
287 DBG("Cleaning up relayd sockets");
288
289 /* Save the net sequence index before destroying the object */
290 netidx = relayd->net_seq_idx;
291
292 /*
293 * Delete the relayd from the relayd hash table, close the sockets and free
294 * the object in a RCU call.
295 */
296 destroy_relayd(relayd);
297
298 /* Set inactive endpoint to all streams */
299 update_endpoint_status_by_netidx(netidx, CONSUMER_ENDPOINT_INACTIVE);
300
301 /*
302 * With a local data context, notify the threads that the streams' state
303 * have changed. The write() action on the pipe acts as an "implicit"
304 * memory barrier ordering the updates of the end point status from the
305 * read of this status which happens AFTER receiving this notify.
306 */
307 if (ctx) {
308 notify_thread_pipe(ctx->consumer_data_pipe[1]);
309 notify_thread_pipe(ctx->consumer_metadata_pipe[1]);
310 }
311 }
312
313 /*
314 * Flag a relayd socket pair for destruction. Destroy it if the refcount
315 * reaches zero.
316 *
317 * RCU read side lock MUST be aquired before calling this function.
318 */
319 void consumer_flag_relayd_for_destroy(struct consumer_relayd_sock_pair *relayd)
320 {
321 assert(relayd);
322
323 /* Set destroy flag for this object */
324 uatomic_set(&relayd->destroy_flag, 1);
325
326 /* Destroy the relayd if refcount is 0 */
327 if (uatomic_read(&relayd->refcount) == 0) {
328 destroy_relayd(relayd);
329 }
330 }
331
332 /*
333 * Remove a stream from the global list protected by a mutex. This
334 * function is also responsible for freeing its data structures.
335 */
336 void consumer_del_stream(struct lttng_consumer_stream *stream,
337 struct lttng_ht *ht)
338 {
339 int ret;
340 struct lttng_ht_iter iter;
341 struct lttng_consumer_channel *free_chan = NULL;
342 struct consumer_relayd_sock_pair *relayd;
343
344 assert(stream);
345
346 DBG("Consumer del stream %d", stream->wait_fd);
347
348 if (ht == NULL) {
349 /* Means the stream was allocated but not successfully added */
350 goto free_stream;
351 }
352
353 pthread_mutex_lock(&consumer_data.lock);
354 pthread_mutex_lock(&stream->lock);
355
356 switch (consumer_data.type) {
357 case LTTNG_CONSUMER_KERNEL:
358 if (stream->mmap_base != NULL) {
359 ret = munmap(stream->mmap_base, stream->mmap_len);
360 if (ret != 0) {
361 PERROR("munmap");
362 }
363 }
364 break;
365 case LTTNG_CONSUMER32_UST:
366 case LTTNG_CONSUMER64_UST:
367 lttng_ustconsumer_del_stream(stream);
368 break;
369 default:
370 ERR("Unknown consumer_data type");
371 assert(0);
372 goto end;
373 }
374
375 rcu_read_lock();
376 iter.iter.node = &stream->node.node;
377 ret = lttng_ht_del(ht, &iter);
378 assert(!ret);
379
380 /* Remove node session id from the consumer_data stream ht */
381 iter.iter.node = &stream->node_session_id.node;
382 ret = lttng_ht_del(consumer_data.stream_list_ht, &iter);
383 assert(!ret);
384 rcu_read_unlock();
385
386 assert(consumer_data.stream_count > 0);
387 consumer_data.stream_count--;
388
389 if (stream->out_fd >= 0) {
390 ret = close(stream->out_fd);
391 if (ret) {
392 PERROR("close");
393 }
394 }
395 if (stream->wait_fd >= 0 && !stream->wait_fd_is_copy) {
396 ret = close(stream->wait_fd);
397 if (ret) {
398 PERROR("close");
399 }
400 }
401 if (stream->shm_fd >= 0 && stream->wait_fd != stream->shm_fd) {
402 ret = close(stream->shm_fd);
403 if (ret) {
404 PERROR("close");
405 }
406 }
407
408 /* Check and cleanup relayd */
409 rcu_read_lock();
410 relayd = consumer_find_relayd(stream->net_seq_idx);
411 if (relayd != NULL) {
412 uatomic_dec(&relayd->refcount);
413 assert(uatomic_read(&relayd->refcount) >= 0);
414
415 /* Closing streams requires to lock the control socket. */
416 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
417 ret = relayd_send_close_stream(&relayd->control_sock,
418 stream->relayd_stream_id,
419 stream->next_net_seq_num - 1);
420 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
421 if (ret < 0) {
422 DBG("Unable to close stream on the relayd. Continuing");
423 /*
424 * Continue here. There is nothing we can do for the relayd.
425 * Chances are that the relayd has closed the socket so we just
426 * continue cleaning up.
427 */
428 }
429
430 /* Both conditions are met, we destroy the relayd. */
431 if (uatomic_read(&relayd->refcount) == 0 &&
432 uatomic_read(&relayd->destroy_flag)) {
433 destroy_relayd(relayd);
434 }
435 }
436 rcu_read_unlock();
437
438 uatomic_dec(&stream->chan->refcount);
439 if (!uatomic_read(&stream->chan->refcount)
440 && !uatomic_read(&stream->chan->nb_init_streams)) {
441 free_chan = stream->chan;
442 }
443
444 end:
445 consumer_data.need_update = 1;
446 pthread_mutex_unlock(&stream->lock);
447 pthread_mutex_unlock(&consumer_data.lock);
448
449 if (free_chan) {
450 consumer_del_channel(free_chan);
451 }
452
453 free_stream:
454 call_rcu(&stream->node.head, consumer_free_stream);
455 }
456
457 struct lttng_consumer_stream *consumer_allocate_stream(
458 int channel_key, int stream_key,
459 int shm_fd, int wait_fd,
460 enum lttng_consumer_stream_state state,
461 uint64_t mmap_len,
462 enum lttng_event_output output,
463 const char *path_name,
464 uid_t uid,
465 gid_t gid,
466 int net_index,
467 int metadata_flag,
468 uint64_t session_id,
469 int *alloc_ret)
470 {
471 struct lttng_consumer_stream *stream;
472
473 stream = zmalloc(sizeof(*stream));
474 if (stream == NULL) {
475 PERROR("malloc struct lttng_consumer_stream");
476 *alloc_ret = -ENOMEM;
477 goto end;
478 }
479
480 rcu_read_lock();
481
482 /*
483 * Get stream's channel reference. Needed when adding the stream to the
484 * global hash table.
485 */
486 stream->chan = consumer_find_channel(channel_key);
487 if (!stream->chan) {
488 *alloc_ret = -ENOENT;
489 ERR("Unable to find channel for stream %d", stream_key);
490 goto error;
491 }
492
493 stream->key = stream_key;
494 stream->shm_fd = shm_fd;
495 stream->wait_fd = wait_fd;
496 stream->out_fd = -1;
497 stream->out_fd_offset = 0;
498 stream->state = state;
499 stream->mmap_len = mmap_len;
500 stream->mmap_base = NULL;
501 stream->output = output;
502 stream->uid = uid;
503 stream->gid = gid;
504 stream->net_seq_idx = net_index;
505 stream->metadata_flag = metadata_flag;
506 stream->session_id = session_id;
507 strncpy(stream->path_name, path_name, sizeof(stream->path_name));
508 stream->path_name[sizeof(stream->path_name) - 1] = '\0';
509 pthread_mutex_init(&stream->lock, NULL);
510
511 /*
512 * Index differently the metadata node because the thread is using an
513 * internal hash table to match streams in the metadata_ht to the epoll set
514 * file descriptor.
515 */
516 if (metadata_flag) {
517 lttng_ht_node_init_ulong(&stream->node, stream->wait_fd);
518 } else {
519 lttng_ht_node_init_ulong(&stream->node, stream->key);
520 }
521
522 /* Init session id node with the stream session id */
523 lttng_ht_node_init_ulong(&stream->node_session_id, stream->session_id);
524
525 /*
526 * The cpu number is needed before using any ustctl_* actions. Ignored for
527 * the kernel so the value does not matter.
528 */
529 pthread_mutex_lock(&consumer_data.lock);
530 stream->cpu = stream->chan->cpucount++;
531 pthread_mutex_unlock(&consumer_data.lock);
532
533 DBG3("Allocated stream %s (key %d, shm_fd %d, wait_fd %d, mmap_len %llu,"
534 " out_fd %d, net_seq_idx %d, session_id %" PRIu64,
535 stream->path_name, stream->key, stream->shm_fd, stream->wait_fd,
536 (unsigned long long) stream->mmap_len, stream->out_fd,
537 stream->net_seq_idx, stream->session_id);
538
539 rcu_read_unlock();
540 return stream;
541
542 error:
543 rcu_read_unlock();
544 free(stream);
545 end:
546 return NULL;
547 }
548
549 /*
550 * Add a stream to the global list protected by a mutex.
551 */
552 static int consumer_add_stream(struct lttng_consumer_stream *stream,
553 struct lttng_ht *ht)
554 {
555 int ret = 0;
556 struct consumer_relayd_sock_pair *relayd;
557
558 assert(stream);
559 assert(ht);
560
561 DBG3("Adding consumer stream %d", stream->key);
562
563 pthread_mutex_lock(&consumer_data.lock);
564 pthread_mutex_lock(&stream->lock);
565 rcu_read_lock();
566
567 /* Steal stream identifier to avoid having streams with the same key */
568 consumer_steal_stream_key(stream->key, ht);
569
570 lttng_ht_add_unique_ulong(ht, &stream->node);
571
572 /*
573 * Add stream to the stream_list_ht of the consumer data. No need to steal
574 * the key since the HT does not use it and we allow to add redundant keys
575 * into this table.
576 */
577 lttng_ht_add_ulong(consumer_data.stream_list_ht, &stream->node_session_id);
578
579 /* Check and cleanup relayd */
580 relayd = consumer_find_relayd(stream->net_seq_idx);
581 if (relayd != NULL) {
582 uatomic_inc(&relayd->refcount);
583 }
584
585 /* Update channel refcount once added without error(s). */
586 uatomic_inc(&stream->chan->refcount);
587
588 /*
589 * When nb_init_streams reaches 0, we don't need to trigger any action in
590 * terms of destroying the associated channel, because the action that
591 * causes the count to become 0 also causes a stream to be added. The
592 * channel deletion will thus be triggered by the following removal of this
593 * stream.
594 */
595 if (uatomic_read(&stream->chan->nb_init_streams) > 0) {
596 uatomic_dec(&stream->chan->nb_init_streams);
597 }
598
599 /* Update consumer data once the node is inserted. */
600 consumer_data.stream_count++;
601 consumer_data.need_update = 1;
602
603 rcu_read_unlock();
604 pthread_mutex_unlock(&stream->lock);
605 pthread_mutex_unlock(&consumer_data.lock);
606
607 return ret;
608 }
609
610 /*
611 * Add relayd socket to global consumer data hashtable. RCU read side lock MUST
612 * be acquired before calling this.
613 */
614 static int add_relayd(struct consumer_relayd_sock_pair *relayd)
615 {
616 int ret = 0;
617 struct lttng_ht_node_ulong *node;
618 struct lttng_ht_iter iter;
619
620 if (relayd == NULL) {
621 ret = -1;
622 goto end;
623 }
624
625 lttng_ht_lookup(consumer_data.relayd_ht,
626 (void *)((unsigned long) relayd->net_seq_idx), &iter);
627 node = lttng_ht_iter_get_node_ulong(&iter);
628 if (node != NULL) {
629 /* Relayd already exist. Ignore the insertion */
630 goto end;
631 }
632 lttng_ht_add_unique_ulong(consumer_data.relayd_ht, &relayd->node);
633
634 end:
635 return ret;
636 }
637
638 /*
639 * Allocate and return a consumer relayd socket.
640 */
641 struct consumer_relayd_sock_pair *consumer_allocate_relayd_sock_pair(
642 int net_seq_idx)
643 {
644 struct consumer_relayd_sock_pair *obj = NULL;
645
646 /* Negative net sequence index is a failure */
647 if (net_seq_idx < 0) {
648 goto error;
649 }
650
651 obj = zmalloc(sizeof(struct consumer_relayd_sock_pair));
652 if (obj == NULL) {
653 PERROR("zmalloc relayd sock");
654 goto error;
655 }
656
657 obj->net_seq_idx = net_seq_idx;
658 obj->refcount = 0;
659 obj->destroy_flag = 0;
660 lttng_ht_node_init_ulong(&obj->node, obj->net_seq_idx);
661 pthread_mutex_init(&obj->ctrl_sock_mutex, NULL);
662
663 error:
664 return obj;
665 }
666
667 /*
668 * Find a relayd socket pair in the global consumer data.
669 *
670 * Return the object if found else NULL.
671 * RCU read-side lock must be held across this call and while using the
672 * returned object.
673 */
674 struct consumer_relayd_sock_pair *consumer_find_relayd(int key)
675 {
676 struct lttng_ht_iter iter;
677 struct lttng_ht_node_ulong *node;
678 struct consumer_relayd_sock_pair *relayd = NULL;
679
680 /* Negative keys are lookup failures */
681 if (key < 0) {
682 goto error;
683 }
684
685 lttng_ht_lookup(consumer_data.relayd_ht, (void *)((unsigned long) key),
686 &iter);
687 node = lttng_ht_iter_get_node_ulong(&iter);
688 if (node != NULL) {
689 relayd = caa_container_of(node, struct consumer_relayd_sock_pair, node);
690 }
691
692 error:
693 return relayd;
694 }
695
696 /*
697 * Handle stream for relayd transmission if the stream applies for network
698 * streaming where the net sequence index is set.
699 *
700 * Return destination file descriptor or negative value on error.
701 */
702 static int write_relayd_stream_header(struct lttng_consumer_stream *stream,
703 size_t data_size, unsigned long padding,
704 struct consumer_relayd_sock_pair *relayd)
705 {
706 int outfd = -1, ret;
707 struct lttcomm_relayd_data_hdr data_hdr;
708
709 /* Safety net */
710 assert(stream);
711 assert(relayd);
712
713 /* Reset data header */
714 memset(&data_hdr, 0, sizeof(data_hdr));
715
716 if (stream->metadata_flag) {
717 /* Caller MUST acquire the relayd control socket lock */
718 ret = relayd_send_metadata(&relayd->control_sock, data_size);
719 if (ret < 0) {
720 goto error;
721 }
722
723 /* Metadata are always sent on the control socket. */
724 outfd = relayd->control_sock.fd;
725 } else {
726 /* Set header with stream information */
727 data_hdr.stream_id = htobe64(stream->relayd_stream_id);
728 data_hdr.data_size = htobe32(data_size);
729 data_hdr.padding_size = htobe32(padding);
730 data_hdr.net_seq_num = htobe64(stream->next_net_seq_num++);
731 /* Other fields are zeroed previously */
732
733 ret = relayd_send_data_hdr(&relayd->data_sock, &data_hdr,
734 sizeof(data_hdr));
735 if (ret < 0) {
736 goto error;
737 }
738
739 /* Set to go on data socket */
740 outfd = relayd->data_sock.fd;
741 }
742
743 error:
744 return outfd;
745 }
746
747 static
748 void consumer_free_channel(struct rcu_head *head)
749 {
750 struct lttng_ht_node_ulong *node =
751 caa_container_of(head, struct lttng_ht_node_ulong, head);
752 struct lttng_consumer_channel *channel =
753 caa_container_of(node, struct lttng_consumer_channel, node);
754
755 free(channel);
756 }
757
758 /*
759 * Remove a channel from the global list protected by a mutex. This
760 * function is also responsible for freeing its data structures.
761 */
762 void consumer_del_channel(struct lttng_consumer_channel *channel)
763 {
764 int ret;
765 struct lttng_ht_iter iter;
766
767 DBG("Consumer delete channel key %d", channel->key);
768
769 pthread_mutex_lock(&consumer_data.lock);
770
771 switch (consumer_data.type) {
772 case LTTNG_CONSUMER_KERNEL:
773 break;
774 case LTTNG_CONSUMER32_UST:
775 case LTTNG_CONSUMER64_UST:
776 lttng_ustconsumer_del_channel(channel);
777 break;
778 default:
779 ERR("Unknown consumer_data type");
780 assert(0);
781 goto end;
782 }
783
784 rcu_read_lock();
785 iter.iter.node = &channel->node.node;
786 ret = lttng_ht_del(consumer_data.channel_ht, &iter);
787 assert(!ret);
788 rcu_read_unlock();
789
790 if (channel->mmap_base != NULL) {
791 ret = munmap(channel->mmap_base, channel->mmap_len);
792 if (ret != 0) {
793 PERROR("munmap");
794 }
795 }
796 if (channel->wait_fd >= 0 && !channel->wait_fd_is_copy) {
797 ret = close(channel->wait_fd);
798 if (ret) {
799 PERROR("close");
800 }
801 }
802 if (channel->shm_fd >= 0 && channel->wait_fd != channel->shm_fd) {
803 ret = close(channel->shm_fd);
804 if (ret) {
805 PERROR("close");
806 }
807 }
808
809 call_rcu(&channel->node.head, consumer_free_channel);
810 end:
811 pthread_mutex_unlock(&consumer_data.lock);
812 }
813
814 struct lttng_consumer_channel *consumer_allocate_channel(
815 int channel_key,
816 int shm_fd, int wait_fd,
817 uint64_t mmap_len,
818 uint64_t max_sb_size,
819 unsigned int nb_init_streams)
820 {
821 struct lttng_consumer_channel *channel;
822 int ret;
823
824 channel = zmalloc(sizeof(*channel));
825 if (channel == NULL) {
826 PERROR("malloc struct lttng_consumer_channel");
827 goto end;
828 }
829 channel->key = channel_key;
830 channel->shm_fd = shm_fd;
831 channel->wait_fd = wait_fd;
832 channel->mmap_len = mmap_len;
833 channel->max_sb_size = max_sb_size;
834 channel->refcount = 0;
835 channel->nb_init_streams = nb_init_streams;
836 lttng_ht_node_init_ulong(&channel->node, channel->key);
837
838 switch (consumer_data.type) {
839 case LTTNG_CONSUMER_KERNEL:
840 channel->mmap_base = NULL;
841 channel->mmap_len = 0;
842 break;
843 case LTTNG_CONSUMER32_UST:
844 case LTTNG_CONSUMER64_UST:
845 ret = lttng_ustconsumer_allocate_channel(channel);
846 if (ret) {
847 free(channel);
848 return NULL;
849 }
850 break;
851 default:
852 ERR("Unknown consumer_data type");
853 assert(0);
854 goto end;
855 }
856 DBG("Allocated channel (key %d, shm_fd %d, wait_fd %d, mmap_len %llu, max_sb_size %llu)",
857 channel->key, channel->shm_fd, channel->wait_fd,
858 (unsigned long long) channel->mmap_len,
859 (unsigned long long) channel->max_sb_size);
860 end:
861 return channel;
862 }
863
864 /*
865 * Add a channel to the global list protected by a mutex.
866 */
867 int consumer_add_channel(struct lttng_consumer_channel *channel)
868 {
869 struct lttng_ht_node_ulong *node;
870 struct lttng_ht_iter iter;
871
872 pthread_mutex_lock(&consumer_data.lock);
873 /* Steal channel identifier, for UST */
874 consumer_steal_channel_key(channel->key);
875 rcu_read_lock();
876
877 lttng_ht_lookup(consumer_data.channel_ht,
878 (void *)((unsigned long) channel->key), &iter);
879 node = lttng_ht_iter_get_node_ulong(&iter);
880 if (node != NULL) {
881 /* Channel already exist. Ignore the insertion */
882 goto end;
883 }
884
885 lttng_ht_add_unique_ulong(consumer_data.channel_ht, &channel->node);
886
887 end:
888 rcu_read_unlock();
889 pthread_mutex_unlock(&consumer_data.lock);
890
891 return 0;
892 }
893
894 /*
895 * Allocate the pollfd structure and the local view of the out fds to avoid
896 * doing a lookup in the linked list and concurrency issues when writing is
897 * needed. Called with consumer_data.lock held.
898 *
899 * Returns the number of fds in the structures.
900 */
901 static int consumer_update_poll_array(
902 struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
903 struct lttng_consumer_stream **local_stream, struct lttng_ht *ht)
904 {
905 int i = 0;
906 struct lttng_ht_iter iter;
907 struct lttng_consumer_stream *stream;
908
909 DBG("Updating poll fd array");
910 rcu_read_lock();
911 cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
912 /*
913 * Only active streams with an active end point can be added to the
914 * poll set and local stream storage of the thread.
915 *
916 * There is a potential race here for endpoint_status to be updated
917 * just after the check. However, this is OK since the stream(s) will
918 * be deleted once the thread is notified that the end point state has
919 * changed where this function will be called back again.
920 */
921 if (stream->state != LTTNG_CONSUMER_ACTIVE_STREAM ||
922 stream->endpoint_status == CONSUMER_ENDPOINT_INACTIVE) {
923 continue;
924 }
925 DBG("Active FD %d", stream->wait_fd);
926 (*pollfd)[i].fd = stream->wait_fd;
927 (*pollfd)[i].events = POLLIN | POLLPRI;
928 local_stream[i] = stream;
929 i++;
930 }
931 rcu_read_unlock();
932
933 /*
934 * Insert the consumer_data_pipe at the end of the array and don't
935 * increment i so nb_fd is the number of real FD.
936 */
937 (*pollfd)[i].fd = ctx->consumer_data_pipe[0];
938 (*pollfd)[i].events = POLLIN | POLLPRI;
939 return i;
940 }
941
942 /*
943 * Poll on the should_quit pipe and the command socket return -1 on error and
944 * should exit, 0 if data is available on the command socket
945 */
946 int lttng_consumer_poll_socket(struct pollfd *consumer_sockpoll)
947 {
948 int num_rdy;
949
950 restart:
951 num_rdy = poll(consumer_sockpoll, 2, -1);
952 if (num_rdy == -1) {
953 /*
954 * Restart interrupted system call.
955 */
956 if (errno == EINTR) {
957 goto restart;
958 }
959 PERROR("Poll error");
960 goto exit;
961 }
962 if (consumer_sockpoll[0].revents & (POLLIN | POLLPRI)) {
963 DBG("consumer_should_quit wake up");
964 goto exit;
965 }
966 return 0;
967
968 exit:
969 return -1;
970 }
971
972 /*
973 * Set the error socket.
974 */
975 void lttng_consumer_set_error_sock(
976 struct lttng_consumer_local_data *ctx, int sock)
977 {
978 ctx->consumer_error_socket = sock;
979 }
980
981 /*
982 * Set the command socket path.
983 */
984 void lttng_consumer_set_command_sock_path(
985 struct lttng_consumer_local_data *ctx, char *sock)
986 {
987 ctx->consumer_command_sock_path = sock;
988 }
989
990 /*
991 * Send return code to the session daemon.
992 * If the socket is not defined, we return 0, it is not a fatal error
993 */
994 int lttng_consumer_send_error(
995 struct lttng_consumer_local_data *ctx, int cmd)
996 {
997 if (ctx->consumer_error_socket > 0) {
998 return lttcomm_send_unix_sock(ctx->consumer_error_socket, &cmd,
999 sizeof(enum lttcomm_sessiond_command));
1000 }
1001
1002 return 0;
1003 }
1004
1005 /*
1006 * Close all the tracefiles and stream fds, should be called when all instances
1007 * are destroyed.
1008 */
1009 void lttng_consumer_cleanup(void)
1010 {
1011 struct lttng_ht_iter iter;
1012 struct lttng_ht_node_ulong *node;
1013
1014 rcu_read_lock();
1015
1016 cds_lfht_for_each_entry(consumer_data.channel_ht->ht, &iter.iter, node,
1017 node) {
1018 struct lttng_consumer_channel *channel =
1019 caa_container_of(node, struct lttng_consumer_channel, node);
1020 consumer_del_channel(channel);
1021 }
1022
1023 rcu_read_unlock();
1024
1025 lttng_ht_destroy(consumer_data.channel_ht);
1026 }
1027
1028 /*
1029 * Called from signal handler.
1030 */
1031 void lttng_consumer_should_exit(struct lttng_consumer_local_data *ctx)
1032 {
1033 int ret;
1034 consumer_quit = 1;
1035 do {
1036 ret = write(ctx->consumer_should_quit[1], "4", 1);
1037 } while (ret < 0 && errno == EINTR);
1038 if (ret < 0) {
1039 PERROR("write consumer quit");
1040 }
1041
1042 DBG("Consumer flag that it should quit");
1043 }
1044
1045 void lttng_consumer_sync_trace_file(struct lttng_consumer_stream *stream,
1046 off_t orig_offset)
1047 {
1048 int outfd = stream->out_fd;
1049
1050 /*
1051 * This does a blocking write-and-wait on any page that belongs to the
1052 * subbuffer prior to the one we just wrote.
1053 * Don't care about error values, as these are just hints and ways to
1054 * limit the amount of page cache used.
1055 */
1056 if (orig_offset < stream->chan->max_sb_size) {
1057 return;
1058 }
1059 lttng_sync_file_range(outfd, orig_offset - stream->chan->max_sb_size,
1060 stream->chan->max_sb_size,
1061 SYNC_FILE_RANGE_WAIT_BEFORE
1062 | SYNC_FILE_RANGE_WRITE
1063 | SYNC_FILE_RANGE_WAIT_AFTER);
1064 /*
1065 * Give hints to the kernel about how we access the file:
1066 * POSIX_FADV_DONTNEED : we won't re-access data in a near future after
1067 * we write it.
1068 *
1069 * We need to call fadvise again after the file grows because the
1070 * kernel does not seem to apply fadvise to non-existing parts of the
1071 * file.
1072 *
1073 * Call fadvise _after_ having waited for the page writeback to
1074 * complete because the dirty page writeback semantic is not well
1075 * defined. So it can be expected to lead to lower throughput in
1076 * streaming.
1077 */
1078 posix_fadvise(outfd, orig_offset - stream->chan->max_sb_size,
1079 stream->chan->max_sb_size, POSIX_FADV_DONTNEED);
1080 }
1081
1082 /*
1083 * Initialise the necessary environnement :
1084 * - create a new context
1085 * - create the poll_pipe
1086 * - create the should_quit pipe (for signal handler)
1087 * - create the thread pipe (for splice)
1088 *
1089 * Takes a function pointer as argument, this function is called when data is
1090 * available on a buffer. This function is responsible to do the
1091 * kernctl_get_next_subbuf, read the data with mmap or splice depending on the
1092 * buffer configuration and then kernctl_put_next_subbuf at the end.
1093 *
1094 * Returns a pointer to the new context or NULL on error.
1095 */
1096 struct lttng_consumer_local_data *lttng_consumer_create(
1097 enum lttng_consumer_type type,
1098 ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream,
1099 struct lttng_consumer_local_data *ctx),
1100 int (*recv_channel)(struct lttng_consumer_channel *channel),
1101 int (*recv_stream)(struct lttng_consumer_stream *stream),
1102 int (*update_stream)(int stream_key, uint32_t state))
1103 {
1104 int ret, i;
1105 struct lttng_consumer_local_data *ctx;
1106
1107 assert(consumer_data.type == LTTNG_CONSUMER_UNKNOWN ||
1108 consumer_data.type == type);
1109 consumer_data.type = type;
1110
1111 ctx = zmalloc(sizeof(struct lttng_consumer_local_data));
1112 if (ctx == NULL) {
1113 PERROR("allocating context");
1114 goto error;
1115 }
1116
1117 ctx->consumer_error_socket = -1;
1118 /* assign the callbacks */
1119 ctx->on_buffer_ready = buffer_ready;
1120 ctx->on_recv_channel = recv_channel;
1121 ctx->on_recv_stream = recv_stream;
1122 ctx->on_update_stream = update_stream;
1123
1124 ret = pipe(ctx->consumer_data_pipe);
1125 if (ret < 0) {
1126 PERROR("Error creating poll pipe");
1127 goto error_poll_pipe;
1128 }
1129
1130 /* set read end of the pipe to non-blocking */
1131 ret = fcntl(ctx->consumer_data_pipe[0], F_SETFL, O_NONBLOCK);
1132 if (ret < 0) {
1133 PERROR("fcntl O_NONBLOCK");
1134 goto error_poll_fcntl;
1135 }
1136
1137 /* set write end of the pipe to non-blocking */
1138 ret = fcntl(ctx->consumer_data_pipe[1], F_SETFL, O_NONBLOCK);
1139 if (ret < 0) {
1140 PERROR("fcntl O_NONBLOCK");
1141 goto error_poll_fcntl;
1142 }
1143
1144 ret = pipe(ctx->consumer_should_quit);
1145 if (ret < 0) {
1146 PERROR("Error creating recv pipe");
1147 goto error_quit_pipe;
1148 }
1149
1150 ret = pipe(ctx->consumer_thread_pipe);
1151 if (ret < 0) {
1152 PERROR("Error creating thread pipe");
1153 goto error_thread_pipe;
1154 }
1155
1156 ret = utils_create_pipe(ctx->consumer_metadata_pipe);
1157 if (ret < 0) {
1158 goto error_metadata_pipe;
1159 }
1160
1161 ret = utils_create_pipe(ctx->consumer_splice_metadata_pipe);
1162 if (ret < 0) {
1163 goto error_splice_pipe;
1164 }
1165
1166 return ctx;
1167
1168 error_splice_pipe:
1169 utils_close_pipe(ctx->consumer_metadata_pipe);
1170 error_metadata_pipe:
1171 utils_close_pipe(ctx->consumer_thread_pipe);
1172 error_thread_pipe:
1173 for (i = 0; i < 2; i++) {
1174 int err;
1175
1176 err = close(ctx->consumer_should_quit[i]);
1177 if (err) {
1178 PERROR("close");
1179 }
1180 }
1181 error_poll_fcntl:
1182 error_quit_pipe:
1183 for (i = 0; i < 2; i++) {
1184 int err;
1185
1186 err = close(ctx->consumer_data_pipe[i]);
1187 if (err) {
1188 PERROR("close");
1189 }
1190 }
1191 error_poll_pipe:
1192 free(ctx);
1193 error:
1194 return NULL;
1195 }
1196
1197 /*
1198 * Close all fds associated with the instance and free the context.
1199 */
1200 void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx)
1201 {
1202 int ret;
1203
1204 DBG("Consumer destroying it. Closing everything.");
1205
1206 ret = close(ctx->consumer_error_socket);
1207 if (ret) {
1208 PERROR("close");
1209 }
1210 ret = close(ctx->consumer_thread_pipe[0]);
1211 if (ret) {
1212 PERROR("close");
1213 }
1214 ret = close(ctx->consumer_thread_pipe[1]);
1215 if (ret) {
1216 PERROR("close");
1217 }
1218 ret = close(ctx->consumer_data_pipe[0]);
1219 if (ret) {
1220 PERROR("close");
1221 }
1222 ret = close(ctx->consumer_data_pipe[1]);
1223 if (ret) {
1224 PERROR("close");
1225 }
1226 ret = close(ctx->consumer_should_quit[0]);
1227 if (ret) {
1228 PERROR("close");
1229 }
1230 ret = close(ctx->consumer_should_quit[1]);
1231 if (ret) {
1232 PERROR("close");
1233 }
1234 utils_close_pipe(ctx->consumer_splice_metadata_pipe);
1235
1236 unlink(ctx->consumer_command_sock_path);
1237 free(ctx);
1238 }
1239
1240 /*
1241 * Write the metadata stream id on the specified file descriptor.
1242 */
1243 static int write_relayd_metadata_id(int fd,
1244 struct lttng_consumer_stream *stream,
1245 struct consumer_relayd_sock_pair *relayd,
1246 unsigned long padding)
1247 {
1248 int ret;
1249 struct lttcomm_relayd_metadata_payload hdr;
1250
1251 hdr.stream_id = htobe64(stream->relayd_stream_id);
1252 hdr.padding_size = htobe32(padding);
1253 do {
1254 ret = write(fd, (void *) &hdr, sizeof(hdr));
1255 } while (ret < 0 && errno == EINTR);
1256 if (ret < 0) {
1257 PERROR("write metadata stream id");
1258 goto end;
1259 }
1260 DBG("Metadata stream id %" PRIu64 " with padding %lu written before data",
1261 stream->relayd_stream_id, padding);
1262
1263 end:
1264 return ret;
1265 }
1266
1267 /*
1268 * Mmap the ring buffer, read it and write the data to the tracefile. This is a
1269 * core function for writing trace buffers to either the local filesystem or
1270 * the network.
1271 *
1272 * It must be called with the stream lock held.
1273 *
1274 * Careful review MUST be put if any changes occur!
1275 *
1276 * Returns the number of bytes written
1277 */
1278 ssize_t lttng_consumer_on_read_subbuffer_mmap(
1279 struct lttng_consumer_local_data *ctx,
1280 struct lttng_consumer_stream *stream, unsigned long len,
1281 unsigned long padding)
1282 {
1283 unsigned long mmap_offset;
1284 ssize_t ret = 0, written = 0;
1285 off_t orig_offset = stream->out_fd_offset;
1286 /* Default is on the disk */
1287 int outfd = stream->out_fd;
1288 struct consumer_relayd_sock_pair *relayd = NULL;
1289 unsigned int relayd_hang_up = 0;
1290
1291 /* RCU lock for the relayd pointer */
1292 rcu_read_lock();
1293
1294 /* Flag that the current stream if set for network streaming. */
1295 if (stream->net_seq_idx != -1) {
1296 relayd = consumer_find_relayd(stream->net_seq_idx);
1297 if (relayd == NULL) {
1298 goto end;
1299 }
1300 }
1301
1302 /* get the offset inside the fd to mmap */
1303 switch (consumer_data.type) {
1304 case LTTNG_CONSUMER_KERNEL:
1305 ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
1306 break;
1307 case LTTNG_CONSUMER32_UST:
1308 case LTTNG_CONSUMER64_UST:
1309 ret = lttng_ustctl_get_mmap_read_offset(stream->chan->handle,
1310 stream->buf, &mmap_offset);
1311 break;
1312 default:
1313 ERR("Unknown consumer_data type");
1314 assert(0);
1315 }
1316 if (ret != 0) {
1317 errno = -ret;
1318 PERROR("tracer ctl get_mmap_read_offset");
1319 written = ret;
1320 goto end;
1321 }
1322
1323 /* Handle stream on the relayd if the output is on the network */
1324 if (relayd) {
1325 unsigned long netlen = len;
1326
1327 /*
1328 * Lock the control socket for the complete duration of the function
1329 * since from this point on we will use the socket.
1330 */
1331 if (stream->metadata_flag) {
1332 /* Metadata requires the control socket. */
1333 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
1334 netlen += sizeof(struct lttcomm_relayd_metadata_payload);
1335 }
1336
1337 ret = write_relayd_stream_header(stream, netlen, padding, relayd);
1338 if (ret >= 0) {
1339 /* Use the returned socket. */
1340 outfd = ret;
1341
1342 /* Write metadata stream id before payload */
1343 if (stream->metadata_flag) {
1344 ret = write_relayd_metadata_id(outfd, stream, relayd, padding);
1345 if (ret < 0) {
1346 written = ret;
1347 /* Socket operation failed. We consider the relayd dead */
1348 if (ret == -EPIPE || ret == -EINVAL) {
1349 relayd_hang_up = 1;
1350 goto write_error;
1351 }
1352 goto end;
1353 }
1354 }
1355 } else {
1356 /* Socket operation failed. We consider the relayd dead */
1357 if (ret == -EPIPE || ret == -EINVAL) {
1358 relayd_hang_up = 1;
1359 goto write_error;
1360 }
1361 /* Else, use the default set before which is the filesystem. */
1362 }
1363 } else {
1364 /* No streaming, we have to set the len with the full padding */
1365 len += padding;
1366 }
1367
1368 while (len > 0) {
1369 do {
1370 ret = write(outfd, stream->mmap_base + mmap_offset, len);
1371 } while (ret < 0 && errno == EINTR);
1372 DBG("Consumer mmap write() ret %zd (len %lu)", ret, len);
1373 if (ret < 0) {
1374 PERROR("Error in file write");
1375 if (written == 0) {
1376 written = ret;
1377 }
1378 /* Socket operation failed. We consider the relayd dead */
1379 if (errno == EPIPE || errno == EINVAL) {
1380 relayd_hang_up = 1;
1381 goto write_error;
1382 }
1383 goto end;
1384 } else if (ret > len) {
1385 PERROR("Error in file write (ret %zd > len %lu)", ret, len);
1386 written += ret;
1387 goto end;
1388 } else {
1389 len -= ret;
1390 mmap_offset += ret;
1391 }
1392
1393 /* This call is useless on a socket so better save a syscall. */
1394 if (!relayd) {
1395 /* This won't block, but will start writeout asynchronously */
1396 lttng_sync_file_range(outfd, stream->out_fd_offset, ret,
1397 SYNC_FILE_RANGE_WRITE);
1398 stream->out_fd_offset += ret;
1399 }
1400 written += ret;
1401 }
1402 lttng_consumer_sync_trace_file(stream, orig_offset);
1403
1404 write_error:
1405 /*
1406 * This is a special case that the relayd has closed its socket. Let's
1407 * cleanup the relayd object and all associated streams.
1408 */
1409 if (relayd && relayd_hang_up) {
1410 cleanup_relayd(relayd, ctx);
1411 }
1412
1413 end:
1414 /* Unlock only if ctrl socket used */
1415 if (relayd && stream->metadata_flag) {
1416 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
1417 }
1418
1419 rcu_read_unlock();
1420 return written;
1421 }
1422
1423 /*
1424 * Splice the data from the ring buffer to the tracefile.
1425 *
1426 * It must be called with the stream lock held.
1427 *
1428 * Returns the number of bytes spliced.
1429 */
1430 ssize_t lttng_consumer_on_read_subbuffer_splice(
1431 struct lttng_consumer_local_data *ctx,
1432 struct lttng_consumer_stream *stream, unsigned long len,
1433 unsigned long padding)
1434 {
1435 ssize_t ret = 0, written = 0, ret_splice = 0;
1436 loff_t offset = 0;
1437 off_t orig_offset = stream->out_fd_offset;
1438 int fd = stream->wait_fd;
1439 /* Default is on the disk */
1440 int outfd = stream->out_fd;
1441 struct consumer_relayd_sock_pair *relayd = NULL;
1442 int *splice_pipe;
1443 unsigned int relayd_hang_up = 0;
1444
1445 switch (consumer_data.type) {
1446 case LTTNG_CONSUMER_KERNEL:
1447 break;
1448 case LTTNG_CONSUMER32_UST:
1449 case LTTNG_CONSUMER64_UST:
1450 /* Not supported for user space tracing */
1451 return -ENOSYS;
1452 default:
1453 ERR("Unknown consumer_data type");
1454 assert(0);
1455 }
1456
1457 /* RCU lock for the relayd pointer */
1458 rcu_read_lock();
1459
1460 /* Flag that the current stream if set for network streaming. */
1461 if (stream->net_seq_idx != -1) {
1462 relayd = consumer_find_relayd(stream->net_seq_idx);
1463 if (relayd == NULL) {
1464 goto end;
1465 }
1466 }
1467
1468 /*
1469 * Choose right pipe for splice. Metadata and trace data are handled by
1470 * different threads hence the use of two pipes in order not to race or
1471 * corrupt the written data.
1472 */
1473 if (stream->metadata_flag) {
1474 splice_pipe = ctx->consumer_splice_metadata_pipe;
1475 } else {
1476 splice_pipe = ctx->consumer_thread_pipe;
1477 }
1478
1479 /* Write metadata stream id before payload */
1480 if (relayd) {
1481 int total_len = len;
1482
1483 if (stream->metadata_flag) {
1484 /*
1485 * Lock the control socket for the complete duration of the function
1486 * since from this point on we will use the socket.
1487 */
1488 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
1489
1490 ret = write_relayd_metadata_id(splice_pipe[1], stream, relayd,
1491 padding);
1492 if (ret < 0) {
1493 written = ret;
1494 /* Socket operation failed. We consider the relayd dead */
1495 if (ret == -EBADF) {
1496 WARN("Remote relayd disconnected. Stopping");
1497 relayd_hang_up = 1;
1498 goto write_error;
1499 }
1500 goto end;
1501 }
1502
1503 total_len += sizeof(struct lttcomm_relayd_metadata_payload);
1504 }
1505
1506 ret = write_relayd_stream_header(stream, total_len, padding, relayd);
1507 if (ret >= 0) {
1508 /* Use the returned socket. */
1509 outfd = ret;
1510 } else {
1511 /* Socket operation failed. We consider the relayd dead */
1512 if (ret == -EBADF) {
1513 WARN("Remote relayd disconnected. Stopping");
1514 relayd_hang_up = 1;
1515 goto write_error;
1516 }
1517 goto end;
1518 }
1519 } else {
1520 /* No streaming, we have to set the len with the full padding */
1521 len += padding;
1522 }
1523
1524 while (len > 0) {
1525 DBG("splice chan to pipe offset %lu of len %lu (fd : %d, pipe: %d)",
1526 (unsigned long)offset, len, fd, splice_pipe[1]);
1527 ret_splice = splice(fd, &offset, splice_pipe[1], NULL, len,
1528 SPLICE_F_MOVE | SPLICE_F_MORE);
1529 DBG("splice chan to pipe, ret %zd", ret_splice);
1530 if (ret_splice < 0) {
1531 PERROR("Error in relay splice");
1532 if (written == 0) {
1533 written = ret_splice;
1534 }
1535 ret = errno;
1536 goto splice_error;
1537 }
1538
1539 /* Handle stream on the relayd if the output is on the network */
1540 if (relayd) {
1541 if (stream->metadata_flag) {
1542 size_t metadata_payload_size =
1543 sizeof(struct lttcomm_relayd_metadata_payload);
1544
1545 /* Update counter to fit the spliced data */
1546 ret_splice += metadata_payload_size;
1547 len += metadata_payload_size;
1548 /*
1549 * We do this so the return value can match the len passed as
1550 * argument to this function.
1551 */
1552 written -= metadata_payload_size;
1553 }
1554 }
1555
1556 /* Splice data out */
1557 ret_splice = splice(splice_pipe[0], NULL, outfd, NULL,
1558 ret_splice, SPLICE_F_MOVE | SPLICE_F_MORE);
1559 DBG("Consumer splice pipe to file, ret %zd", ret_splice);
1560 if (ret_splice < 0) {
1561 PERROR("Error in file splice");
1562 if (written == 0) {
1563 written = ret_splice;
1564 }
1565 /* Socket operation failed. We consider the relayd dead */
1566 if (errno == EBADF || errno == EPIPE) {
1567 WARN("Remote relayd disconnected. Stopping");
1568 relayd_hang_up = 1;
1569 goto write_error;
1570 }
1571 ret = errno;
1572 goto splice_error;
1573 } else if (ret_splice > len) {
1574 errno = EINVAL;
1575 PERROR("Wrote more data than requested %zd (len: %lu)",
1576 ret_splice, len);
1577 written += ret_splice;
1578 ret = errno;
1579 goto splice_error;
1580 }
1581 len -= ret_splice;
1582
1583 /* This call is useless on a socket so better save a syscall. */
1584 if (!relayd) {
1585 /* This won't block, but will start writeout asynchronously */
1586 lttng_sync_file_range(outfd, stream->out_fd_offset, ret_splice,
1587 SYNC_FILE_RANGE_WRITE);
1588 stream->out_fd_offset += ret_splice;
1589 }
1590 written += ret_splice;
1591 }
1592 lttng_consumer_sync_trace_file(stream, orig_offset);
1593
1594 ret = ret_splice;
1595
1596 goto end;
1597
1598 write_error:
1599 /*
1600 * This is a special case that the relayd has closed its socket. Let's
1601 * cleanup the relayd object and all associated streams.
1602 */
1603 if (relayd && relayd_hang_up) {
1604 cleanup_relayd(relayd, ctx);
1605 /* Skip splice error so the consumer does not fail */
1606 goto end;
1607 }
1608
1609 splice_error:
1610 /* send the appropriate error description to sessiond */
1611 switch (ret) {
1612 case EINVAL:
1613 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_EINVAL);
1614 break;
1615 case ENOMEM:
1616 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_ENOMEM);
1617 break;
1618 case ESPIPE:
1619 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_ESPIPE);
1620 break;
1621 }
1622
1623 end:
1624 if (relayd && stream->metadata_flag) {
1625 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
1626 }
1627
1628 rcu_read_unlock();
1629 return written;
1630 }
1631
1632 /*
1633 * Take a snapshot for a specific fd
1634 *
1635 * Returns 0 on success, < 0 on error
1636 */
1637 int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
1638 struct lttng_consumer_stream *stream)
1639 {
1640 switch (consumer_data.type) {
1641 case LTTNG_CONSUMER_KERNEL:
1642 return lttng_kconsumer_take_snapshot(ctx, stream);
1643 case LTTNG_CONSUMER32_UST:
1644 case LTTNG_CONSUMER64_UST:
1645 return lttng_ustconsumer_take_snapshot(ctx, stream);
1646 default:
1647 ERR("Unknown consumer_data type");
1648 assert(0);
1649 return -ENOSYS;
1650 }
1651
1652 }
1653
1654 /*
1655 * Get the produced position
1656 *
1657 * Returns 0 on success, < 0 on error
1658 */
1659 int lttng_consumer_get_produced_snapshot(
1660 struct lttng_consumer_local_data *ctx,
1661 struct lttng_consumer_stream *stream,
1662 unsigned long *pos)
1663 {
1664 switch (consumer_data.type) {
1665 case LTTNG_CONSUMER_KERNEL:
1666 return lttng_kconsumer_get_produced_snapshot(ctx, stream, pos);
1667 case LTTNG_CONSUMER32_UST:
1668 case LTTNG_CONSUMER64_UST:
1669 return lttng_ustconsumer_get_produced_snapshot(ctx, stream, pos);
1670 default:
1671 ERR("Unknown consumer_data type");
1672 assert(0);
1673 return -ENOSYS;
1674 }
1675 }
1676
1677 int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
1678 int sock, struct pollfd *consumer_sockpoll)
1679 {
1680 switch (consumer_data.type) {
1681 case LTTNG_CONSUMER_KERNEL:
1682 return lttng_kconsumer_recv_cmd(ctx, sock, consumer_sockpoll);
1683 case LTTNG_CONSUMER32_UST:
1684 case LTTNG_CONSUMER64_UST:
1685 return lttng_ustconsumer_recv_cmd(ctx, sock, consumer_sockpoll);
1686 default:
1687 ERR("Unknown consumer_data type");
1688 assert(0);
1689 return -ENOSYS;
1690 }
1691 }
1692
1693 /*
1694 * Iterate over all streams of the hashtable and free them properly.
1695 *
1696 * WARNING: *MUST* be used with data stream only.
1697 */
1698 static void destroy_data_stream_ht(struct lttng_ht *ht)
1699 {
1700 struct lttng_ht_iter iter;
1701 struct lttng_consumer_stream *stream;
1702
1703 if (ht == NULL) {
1704 return;
1705 }
1706
1707 rcu_read_lock();
1708 cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
1709 /*
1710 * Ignore return value since we are currently cleaning up so any error
1711 * can't be handled.
1712 */
1713 (void) consumer_del_stream(stream, ht);
1714 }
1715 rcu_read_unlock();
1716
1717 lttng_ht_destroy(ht);
1718 }
1719
1720 /*
1721 * Iterate over all streams of the hashtable and free them properly.
1722 *
1723 * XXX: Should not be only for metadata stream or else use an other name.
1724 */
1725 static void destroy_stream_ht(struct lttng_ht *ht)
1726 {
1727 struct lttng_ht_iter iter;
1728 struct lttng_consumer_stream *stream;
1729
1730 if (ht == NULL) {
1731 return;
1732 }
1733
1734 rcu_read_lock();
1735 cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
1736 /*
1737 * Ignore return value since we are currently cleaning up so any error
1738 * can't be handled.
1739 */
1740 (void) consumer_del_metadata_stream(stream, ht);
1741 }
1742 rcu_read_unlock();
1743
1744 lttng_ht_destroy(ht);
1745 }
1746
1747 /*
1748 * Clean up a metadata stream and free its memory.
1749 */
1750 void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
1751 struct lttng_ht *ht)
1752 {
1753 int ret;
1754 struct lttng_ht_iter iter;
1755 struct lttng_consumer_channel *free_chan = NULL;
1756 struct consumer_relayd_sock_pair *relayd;
1757
1758 assert(stream);
1759 /*
1760 * This call should NEVER receive regular stream. It must always be
1761 * metadata stream and this is crucial for data structure synchronization.
1762 */
1763 assert(stream->metadata_flag);
1764
1765 DBG3("Consumer delete metadata stream %d", stream->wait_fd);
1766
1767 if (ht == NULL) {
1768 /* Means the stream was allocated but not successfully added */
1769 goto free_stream;
1770 }
1771
1772 pthread_mutex_lock(&consumer_data.lock);
1773 pthread_mutex_lock(&stream->lock);
1774
1775 switch (consumer_data.type) {
1776 case LTTNG_CONSUMER_KERNEL:
1777 if (stream->mmap_base != NULL) {
1778 ret = munmap(stream->mmap_base, stream->mmap_len);
1779 if (ret != 0) {
1780 PERROR("munmap metadata stream");
1781 }
1782 }
1783 break;
1784 case LTTNG_CONSUMER32_UST:
1785 case LTTNG_CONSUMER64_UST:
1786 lttng_ustconsumer_del_stream(stream);
1787 break;
1788 default:
1789 ERR("Unknown consumer_data type");
1790 assert(0);
1791 goto end;
1792 }
1793
1794 rcu_read_lock();
1795 iter.iter.node = &stream->node.node;
1796 ret = lttng_ht_del(ht, &iter);
1797 assert(!ret);
1798
1799 /* Remove node session id from the consumer_data stream ht */
1800 iter.iter.node = &stream->node_session_id.node;
1801 ret = lttng_ht_del(consumer_data.stream_list_ht, &iter);
1802 assert(!ret);
1803 rcu_read_unlock();
1804
1805 if (stream->out_fd >= 0) {
1806 ret = close(stream->out_fd);
1807 if (ret) {
1808 PERROR("close");
1809 }
1810 }
1811
1812 if (stream->wait_fd >= 0 && !stream->wait_fd_is_copy) {
1813 ret = close(stream->wait_fd);
1814 if (ret) {
1815 PERROR("close");
1816 }
1817 }
1818
1819 if (stream->shm_fd >= 0 && stream->wait_fd != stream->shm_fd) {
1820 ret = close(stream->shm_fd);
1821 if (ret) {
1822 PERROR("close");
1823 }
1824 }
1825
1826 /* Check and cleanup relayd */
1827 rcu_read_lock();
1828 relayd = consumer_find_relayd(stream->net_seq_idx);
1829 if (relayd != NULL) {
1830 uatomic_dec(&relayd->refcount);
1831 assert(uatomic_read(&relayd->refcount) >= 0);
1832
1833 /* Closing streams requires to lock the control socket. */
1834 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
1835 ret = relayd_send_close_stream(&relayd->control_sock,
1836 stream->relayd_stream_id, stream->next_net_seq_num - 1);
1837 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
1838 if (ret < 0) {
1839 DBG("Unable to close stream on the relayd. Continuing");
1840 /*
1841 * Continue here. There is nothing we can do for the relayd.
1842 * Chances are that the relayd has closed the socket so we just
1843 * continue cleaning up.
1844 */
1845 }
1846
1847 /* Both conditions are met, we destroy the relayd. */
1848 if (uatomic_read(&relayd->refcount) == 0 &&
1849 uatomic_read(&relayd->destroy_flag)) {
1850 destroy_relayd(relayd);
1851 }
1852 }
1853 rcu_read_unlock();
1854
1855 /* Atomically decrement channel refcount since other threads can use it. */
1856 uatomic_dec(&stream->chan->refcount);
1857 if (!uatomic_read(&stream->chan->refcount)
1858 && !uatomic_read(&stream->chan->nb_init_streams)) {
1859 /* Go for channel deletion! */
1860 free_chan = stream->chan;
1861 }
1862
1863 end:
1864 pthread_mutex_unlock(&stream->lock);
1865 pthread_mutex_unlock(&consumer_data.lock);
1866
1867 if (free_chan) {
1868 consumer_del_channel(free_chan);
1869 }
1870
1871 free_stream:
1872 call_rcu(&stream->node.head, consumer_free_stream);
1873 }
1874
1875 /*
1876 * Action done with the metadata stream when adding it to the consumer internal
1877 * data structures to handle it.
1878 */
1879 static int consumer_add_metadata_stream(struct lttng_consumer_stream *stream,
1880 struct lttng_ht *ht)
1881 {
1882 int ret = 0;
1883 struct consumer_relayd_sock_pair *relayd;
1884 struct lttng_ht_iter iter;
1885 struct lttng_ht_node_ulong *node;
1886
1887 assert(stream);
1888 assert(ht);
1889
1890 DBG3("Adding metadata stream %d to hash table", stream->wait_fd);
1891
1892 pthread_mutex_lock(&consumer_data.lock);
1893 pthread_mutex_lock(&stream->lock);
1894
1895 /*
1896 * From here, refcounts are updated so be _careful_ when returning an error
1897 * after this point.
1898 */
1899
1900 rcu_read_lock();
1901
1902 /*
1903 * Lookup the stream just to make sure it does not exist in our internal
1904 * state. This should NEVER happen.
1905 */
1906 lttng_ht_lookup(ht, (void *)((unsigned long) stream->wait_fd), &iter);
1907 node = lttng_ht_iter_get_node_ulong(&iter);
1908 assert(!node);
1909
1910 /* Find relayd and, if one is found, increment refcount. */
1911 relayd = consumer_find_relayd(stream->net_seq_idx);
1912 if (relayd != NULL) {
1913 uatomic_inc(&relayd->refcount);
1914 }
1915
1916 /* Update channel refcount once added without error(s). */
1917 uatomic_inc(&stream->chan->refcount);
1918
1919 /*
1920 * When nb_init_streams reaches 0, we don't need to trigger any action in
1921 * terms of destroying the associated channel, because the action that
1922 * causes the count to become 0 also causes a stream to be added. The
1923 * channel deletion will thus be triggered by the following removal of this
1924 * stream.
1925 */
1926 if (uatomic_read(&stream->chan->nb_init_streams) > 0) {
1927 uatomic_dec(&stream->chan->nb_init_streams);
1928 }
1929
1930 lttng_ht_add_unique_ulong(ht, &stream->node);
1931
1932 /*
1933 * Add stream to the stream_list_ht of the consumer data. No need to steal
1934 * the key since the HT does not use it and we allow to add redundant keys
1935 * into this table.
1936 */
1937 lttng_ht_add_ulong(consumer_data.stream_list_ht, &stream->node_session_id);
1938
1939 rcu_read_unlock();
1940
1941 pthread_mutex_unlock(&stream->lock);
1942 pthread_mutex_unlock(&consumer_data.lock);
1943 return ret;
1944 }
1945
1946 /*
1947 * Delete data stream that are flagged for deletion (endpoint_status).
1948 */
1949 static void validate_endpoint_status_data_stream(void)
1950 {
1951 struct lttng_ht_iter iter;
1952 struct lttng_consumer_stream *stream;
1953
1954 DBG("Consumer delete flagged data stream");
1955
1956 rcu_read_lock();
1957 cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) {
1958 /* Validate delete flag of the stream */
1959 if (stream->endpoint_status == CONSUMER_ENDPOINT_ACTIVE) {
1960 continue;
1961 }
1962 /* Delete it right now */
1963 consumer_del_stream(stream, data_ht);
1964 }
1965 rcu_read_unlock();
1966 }
1967
1968 /*
1969 * Delete metadata stream that are flagged for deletion (endpoint_status).
1970 */
1971 static void validate_endpoint_status_metadata_stream(
1972 struct lttng_poll_event *pollset)
1973 {
1974 struct lttng_ht_iter iter;
1975 struct lttng_consumer_stream *stream;
1976
1977 DBG("Consumer delete flagged metadata stream");
1978
1979 assert(pollset);
1980
1981 rcu_read_lock();
1982 cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) {
1983 /* Validate delete flag of the stream */
1984 if (stream->endpoint_status == CONSUMER_ENDPOINT_ACTIVE) {
1985 continue;
1986 }
1987 /*
1988 * Remove from pollset so the metadata thread can continue without
1989 * blocking on a deleted stream.
1990 */
1991 lttng_poll_del(pollset, stream->wait_fd);
1992
1993 /* Delete it right now */
1994 consumer_del_metadata_stream(stream, metadata_ht);
1995 }
1996 rcu_read_unlock();
1997 }
1998
1999 /*
2000 * Thread polls on metadata file descriptor and write them on disk or on the
2001 * network.
2002 */
2003 void *consumer_thread_metadata_poll(void *data)
2004 {
2005 int ret, i, pollfd;
2006 uint32_t revents, nb_fd;
2007 struct lttng_consumer_stream *stream = NULL;
2008 struct lttng_ht_iter iter;
2009 struct lttng_ht_node_ulong *node;
2010 struct lttng_poll_event events;
2011 struct lttng_consumer_local_data *ctx = data;
2012 ssize_t len;
2013
2014 rcu_register_thread();
2015
2016 metadata_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
2017 if (!metadata_ht) {
2018 /* ENOMEM at this point. Better to bail out. */
2019 goto error;
2020 }
2021
2022 DBG("Thread metadata poll started");
2023
2024 /* Size is set to 1 for the consumer_metadata pipe */
2025 ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
2026 if (ret < 0) {
2027 ERR("Poll set creation failed");
2028 goto end;
2029 }
2030
2031 ret = lttng_poll_add(&events, ctx->consumer_metadata_pipe[0], LPOLLIN);
2032 if (ret < 0) {
2033 goto end;
2034 }
2035
2036 /* Main loop */
2037 DBG("Metadata main loop started");
2038
2039 while (1) {
2040 lttng_poll_reset(&events);
2041
2042 nb_fd = LTTNG_POLL_GETNB(&events);
2043
2044 /* Only the metadata pipe is set */
2045 if (nb_fd == 0 && consumer_quit == 1) {
2046 goto end;
2047 }
2048
2049 restart:
2050 DBG("Metadata poll wait with %d fd(s)", nb_fd);
2051 ret = lttng_poll_wait(&events, -1);
2052 DBG("Metadata event catched in thread");
2053 if (ret < 0) {
2054 if (errno == EINTR) {
2055 ERR("Poll EINTR catched");
2056 goto restart;
2057 }
2058 goto error;
2059 }
2060
2061 /* From here, the event is a metadata wait fd */
2062 for (i = 0; i < nb_fd; i++) {
2063 revents = LTTNG_POLL_GETEV(&events, i);
2064 pollfd = LTTNG_POLL_GETFD(&events, i);
2065
2066 /* Just don't waste time if no returned events for the fd */
2067 if (!revents) {
2068 continue;
2069 }
2070
2071 if (pollfd == ctx->consumer_metadata_pipe[0]) {
2072 if (revents & (LPOLLERR | LPOLLHUP )) {
2073 DBG("Metadata thread pipe hung up");
2074 /*
2075 * Remove the pipe from the poll set and continue the loop
2076 * since their might be data to consume.
2077 */
2078 lttng_poll_del(&events, ctx->consumer_metadata_pipe[0]);
2079 ret = close(ctx->consumer_metadata_pipe[0]);
2080 if (ret < 0) {
2081 PERROR("close metadata pipe");
2082 }
2083 continue;
2084 } else if (revents & LPOLLIN) {
2085 do {
2086 /* Get the stream pointer received */
2087 ret = read(pollfd, &stream, sizeof(stream));
2088 } while (ret < 0 && errno == EINTR);
2089 if (ret < 0 ||
2090 ret < sizeof(struct lttng_consumer_stream *)) {
2091 PERROR("read metadata stream");
2092 /*
2093 * Let's continue here and hope we can still work
2094 * without stopping the consumer. XXX: Should we?
2095 */
2096 continue;
2097 }
2098
2099 /* A NULL stream means that the state has changed. */
2100 if (stream == NULL) {
2101 /* Check for deleted streams. */
2102 validate_endpoint_status_metadata_stream(&events);
2103 continue;
2104 }
2105
2106 DBG("Adding metadata stream %d to poll set",
2107 stream->wait_fd);
2108
2109 ret = consumer_add_metadata_stream(stream, metadata_ht);
2110 if (ret) {
2111 ERR("Unable to add metadata stream");
2112 /* Stream was not setup properly. Continuing. */
2113 consumer_del_metadata_stream(stream, NULL);
2114 continue;
2115 }
2116
2117 /* Add metadata stream to the global poll events list */
2118 lttng_poll_add(&events, stream->wait_fd,
2119 LPOLLIN | LPOLLPRI);
2120 }
2121
2122 /* Handle other stream */
2123 continue;
2124 }
2125
2126 rcu_read_lock();
2127 lttng_ht_lookup(metadata_ht, (void *)((unsigned long) pollfd),
2128 &iter);
2129 node = lttng_ht_iter_get_node_ulong(&iter);
2130 assert(node);
2131
2132 stream = caa_container_of(node, struct lttng_consumer_stream,
2133 node);
2134
2135 /* Check for error event */
2136 if (revents & (LPOLLERR | LPOLLHUP)) {
2137 DBG("Metadata fd %d is hup|err.", pollfd);
2138 if (!stream->hangup_flush_done
2139 && (consumer_data.type == LTTNG_CONSUMER32_UST
2140 || consumer_data.type == LTTNG_CONSUMER64_UST)) {
2141 DBG("Attempting to flush and consume the UST buffers");
2142 lttng_ustconsumer_on_stream_hangup(stream);
2143
2144 /* We just flushed the stream now read it. */
2145 do {
2146 len = ctx->on_buffer_ready(stream, ctx);
2147 /*
2148 * We don't check the return value here since if we get
2149 * a negative len, it means an error occured thus we
2150 * simply remove it from the poll set and free the
2151 * stream.
2152 */
2153 } while (len > 0);
2154 }
2155
2156 lttng_poll_del(&events, stream->wait_fd);
2157 /*
2158 * This call update the channel states, closes file descriptors
2159 * and securely free the stream.
2160 */
2161 consumer_del_metadata_stream(stream, metadata_ht);
2162 } else if (revents & (LPOLLIN | LPOLLPRI)) {
2163 /* Get the data out of the metadata file descriptor */
2164 DBG("Metadata available on fd %d", pollfd);
2165 assert(stream->wait_fd == pollfd);
2166
2167 len = ctx->on_buffer_ready(stream, ctx);
2168 /* It's ok to have an unavailable sub-buffer */
2169 if (len < 0 && len != -EAGAIN && len != -ENODATA) {
2170 /* Clean up stream from consumer and free it. */
2171 lttng_poll_del(&events, stream->wait_fd);
2172 consumer_del_metadata_stream(stream, metadata_ht);
2173 } else if (len > 0) {
2174 stream->data_read = 1;
2175 }
2176 }
2177
2178 /* Release RCU lock for the stream looked up */
2179 rcu_read_unlock();
2180 }
2181 }
2182
2183 error:
2184 end:
2185 DBG("Metadata poll thread exiting");
2186 lttng_poll_clean(&events);
2187
2188 destroy_stream_ht(metadata_ht);
2189
2190 rcu_unregister_thread();
2191 return NULL;
2192 }
2193
2194 /*
2195 * This thread polls the fds in the set to consume the data and write
2196 * it to tracefile if necessary.
2197 */
2198 void *consumer_thread_data_poll(void *data)
2199 {
2200 int num_rdy, num_hup, high_prio, ret, i;
2201 struct pollfd *pollfd = NULL;
2202 /* local view of the streams */
2203 struct lttng_consumer_stream **local_stream = NULL, *new_stream = NULL;
2204 /* local view of consumer_data.fds_count */
2205 int nb_fd = 0;
2206 struct lttng_consumer_local_data *ctx = data;
2207 ssize_t len;
2208
2209 rcu_register_thread();
2210
2211 data_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
2212 if (data_ht == NULL) {
2213 /* ENOMEM at this point. Better to bail out. */
2214 goto end;
2215 }
2216
2217 local_stream = zmalloc(sizeof(struct lttng_consumer_stream));
2218
2219 while (1) {
2220 high_prio = 0;
2221 num_hup = 0;
2222
2223 /*
2224 * the fds set has been updated, we need to update our
2225 * local array as well
2226 */
2227 pthread_mutex_lock(&consumer_data.lock);
2228 if (consumer_data.need_update) {
2229 if (pollfd != NULL) {
2230 free(pollfd);
2231 pollfd = NULL;
2232 }
2233 if (local_stream != NULL) {
2234 free(local_stream);
2235 local_stream = NULL;
2236 }
2237
2238 /* allocate for all fds + 1 for the consumer_data_pipe */
2239 pollfd = zmalloc((consumer_data.stream_count + 1) * sizeof(struct pollfd));
2240 if (pollfd == NULL) {
2241 PERROR("pollfd malloc");
2242 pthread_mutex_unlock(&consumer_data.lock);
2243 goto end;
2244 }
2245
2246 /* allocate for all fds + 1 for the consumer_data_pipe */
2247 local_stream = zmalloc((consumer_data.stream_count + 1) *
2248 sizeof(struct lttng_consumer_stream));
2249 if (local_stream == NULL) {
2250 PERROR("local_stream malloc");
2251 pthread_mutex_unlock(&consumer_data.lock);
2252 goto end;
2253 }
2254 ret = consumer_update_poll_array(ctx, &pollfd, local_stream,
2255 data_ht);
2256 if (ret < 0) {
2257 ERR("Error in allocating pollfd or local_outfds");
2258 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_POLL_ERROR);
2259 pthread_mutex_unlock(&consumer_data.lock);
2260 goto end;
2261 }
2262 nb_fd = ret;
2263 consumer_data.need_update = 0;
2264 }
2265 pthread_mutex_unlock(&consumer_data.lock);
2266
2267 /* No FDs and consumer_quit, consumer_cleanup the thread */
2268 if (nb_fd == 0 && consumer_quit == 1) {
2269 goto end;
2270 }
2271 /* poll on the array of fds */
2272 restart:
2273 DBG("polling on %d fd", nb_fd + 1);
2274 num_rdy = poll(pollfd, nb_fd + 1, -1);
2275 DBG("poll num_rdy : %d", num_rdy);
2276 if (num_rdy == -1) {
2277 /*
2278 * Restart interrupted system call.
2279 */
2280 if (errno == EINTR) {
2281 goto restart;
2282 }
2283 PERROR("Poll error");
2284 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_POLL_ERROR);
2285 goto end;
2286 } else if (num_rdy == 0) {
2287 DBG("Polling thread timed out");
2288 goto end;
2289 }
2290
2291 /*
2292 * If the consumer_data_pipe triggered poll go directly to the
2293 * beginning of the loop to update the array. We want to prioritize
2294 * array update over low-priority reads.
2295 */
2296 if (pollfd[nb_fd].revents & (POLLIN | POLLPRI)) {
2297 size_t pipe_readlen;
2298
2299 DBG("consumer_data_pipe wake up");
2300 /* Consume 1 byte of pipe data */
2301 do {
2302 pipe_readlen = read(ctx->consumer_data_pipe[0], &new_stream,
2303 sizeof(new_stream));
2304 } while (pipe_readlen == -1 && errno == EINTR);
2305
2306 /*
2307 * If the stream is NULL, just ignore it. It's also possible that
2308 * the sessiond poll thread changed the consumer_quit state and is
2309 * waking us up to test it.
2310 */
2311 if (new_stream == NULL) {
2312 validate_endpoint_status_data_stream();
2313 continue;
2314 }
2315
2316 ret = consumer_add_stream(new_stream, data_ht);
2317 if (ret) {
2318 ERR("Consumer add stream %d failed. Continuing",
2319 new_stream->key);
2320 /*
2321 * At this point, if the add_stream fails, it is not in the
2322 * hash table thus passing the NULL value here.
2323 */
2324 consumer_del_stream(new_stream, NULL);
2325 }
2326
2327 /* Continue to update the local streams and handle prio ones */
2328 continue;
2329 }
2330
2331 /* Take care of high priority channels first. */
2332 for (i = 0; i < nb_fd; i++) {
2333 if (local_stream[i] == NULL) {
2334 continue;
2335 }
2336 if (pollfd[i].revents & POLLPRI) {
2337 DBG("Urgent read on fd %d", pollfd[i].fd);
2338 high_prio = 1;
2339 len = ctx->on_buffer_ready(local_stream[i], ctx);
2340 /* it's ok to have an unavailable sub-buffer */
2341 if (len < 0 && len != -EAGAIN && len != -ENODATA) {
2342 /* Clean the stream and free it. */
2343 consumer_del_stream(local_stream[i], data_ht);
2344 local_stream[i] = NULL;
2345 } else if (len > 0) {
2346 local_stream[i]->data_read = 1;
2347 }
2348 }
2349 }
2350
2351 /*
2352 * If we read high prio channel in this loop, try again
2353 * for more high prio data.
2354 */
2355 if (high_prio) {
2356 continue;
2357 }
2358
2359 /* Take care of low priority channels. */
2360 for (i = 0; i < nb_fd; i++) {
2361 if (local_stream[i] == NULL) {
2362 continue;
2363 }
2364 if ((pollfd[i].revents & POLLIN) ||
2365 local_stream[i]->hangup_flush_done) {
2366 DBG("Normal read on fd %d", pollfd[i].fd);
2367 len = ctx->on_buffer_ready(local_stream[i], ctx);
2368 /* it's ok to have an unavailable sub-buffer */
2369 if (len < 0 && len != -EAGAIN && len != -ENODATA) {
2370 /* Clean the stream and free it. */
2371 consumer_del_stream(local_stream[i], data_ht);
2372 local_stream[i] = NULL;
2373 } else if (len > 0) {
2374 local_stream[i]->data_read = 1;
2375 }
2376 }
2377 }
2378
2379 /* Handle hangup and errors */
2380 for (i = 0; i < nb_fd; i++) {
2381 if (local_stream[i] == NULL) {
2382 continue;
2383 }
2384 if (!local_stream[i]->hangup_flush_done
2385 && (pollfd[i].revents & (POLLHUP | POLLERR | POLLNVAL))
2386 && (consumer_data.type == LTTNG_CONSUMER32_UST
2387 || consumer_data.type == LTTNG_CONSUMER64_UST)) {
2388 DBG("fd %d is hup|err|nval. Attempting flush and read.",
2389 pollfd[i].fd);
2390 lttng_ustconsumer_on_stream_hangup(local_stream[i]);
2391 /* Attempt read again, for the data we just flushed. */
2392 local_stream[i]->data_read = 1;
2393 }
2394 /*
2395 * If the poll flag is HUP/ERR/NVAL and we have
2396 * read no data in this pass, we can remove the
2397 * stream from its hash table.
2398 */
2399 if ((pollfd[i].revents & POLLHUP)) {
2400 DBG("Polling fd %d tells it has hung up.", pollfd[i].fd);
2401 if (!local_stream[i]->data_read) {
2402 consumer_del_stream(local_stream[i], data_ht);
2403 local_stream[i] = NULL;
2404 num_hup++;
2405 }
2406 } else if (pollfd[i].revents & POLLERR) {
2407 ERR("Error returned in polling fd %d.", pollfd[i].fd);
2408 if (!local_stream[i]->data_read) {
2409 consumer_del_stream(local_stream[i], data_ht);
2410 local_stream[i] = NULL;
2411 num_hup++;
2412 }
2413 } else if (pollfd[i].revents & POLLNVAL) {
2414 ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
2415 if (!local_stream[i]->data_read) {
2416 consumer_del_stream(local_stream[i], data_ht);
2417 local_stream[i] = NULL;
2418 num_hup++;
2419 }
2420 }
2421 if (local_stream[i] != NULL) {
2422 local_stream[i]->data_read = 0;
2423 }
2424 }
2425 }
2426 end:
2427 DBG("polling thread exiting");
2428 if (pollfd != NULL) {
2429 free(pollfd);
2430 pollfd = NULL;
2431 }
2432 if (local_stream != NULL) {
2433 free(local_stream);
2434 local_stream = NULL;
2435 }
2436
2437 /*
2438 * Close the write side of the pipe so epoll_wait() in
2439 * consumer_thread_metadata_poll can catch it. The thread is monitoring the
2440 * read side of the pipe. If we close them both, epoll_wait strangely does
2441 * not return and could create a endless wait period if the pipe is the
2442 * only tracked fd in the poll set. The thread will take care of closing
2443 * the read side.
2444 */
2445 ret = close(ctx->consumer_metadata_pipe[1]);
2446 if (ret < 0) {
2447 PERROR("close data pipe");
2448 }
2449
2450 destroy_data_stream_ht(data_ht);
2451
2452 rcu_unregister_thread();
2453 return NULL;
2454 }
2455
2456 /*
2457 * This thread listens on the consumerd socket and receives the file
2458 * descriptors from the session daemon.
2459 */
2460 void *consumer_thread_sessiond_poll(void *data)
2461 {
2462 int sock = -1, client_socket, ret;
2463 /*
2464 * structure to poll for incoming data on communication socket avoids
2465 * making blocking sockets.
2466 */
2467 struct pollfd consumer_sockpoll[2];
2468 struct lttng_consumer_local_data *ctx = data;
2469
2470 rcu_register_thread();
2471
2472 DBG("Creating command socket %s", ctx->consumer_command_sock_path);
2473 unlink(ctx->consumer_command_sock_path);
2474 client_socket = lttcomm_create_unix_sock(ctx->consumer_command_sock_path);
2475 if (client_socket < 0) {
2476 ERR("Cannot create command socket");
2477 goto end;
2478 }
2479
2480 ret = lttcomm_listen_unix_sock(client_socket);
2481 if (ret < 0) {
2482 goto end;
2483 }
2484
2485 DBG("Sending ready command to lttng-sessiond");
2486 ret = lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_COMMAND_SOCK_READY);
2487 /* return < 0 on error, but == 0 is not fatal */
2488 if (ret < 0) {
2489 ERR("Error sending ready command to lttng-sessiond");
2490 goto end;
2491 }
2492
2493 ret = fcntl(client_socket, F_SETFL, O_NONBLOCK);
2494 if (ret < 0) {
2495 PERROR("fcntl O_NONBLOCK");
2496 goto end;
2497 }
2498
2499 /* prepare the FDs to poll : to client socket and the should_quit pipe */
2500 consumer_sockpoll[0].fd = ctx->consumer_should_quit[0];
2501 consumer_sockpoll[0].events = POLLIN | POLLPRI;
2502 consumer_sockpoll[1].fd = client_socket;
2503 consumer_sockpoll[1].events = POLLIN | POLLPRI;
2504
2505 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
2506 goto end;
2507 }
2508 DBG("Connection on client_socket");
2509
2510 /* Blocking call, waiting for transmission */
2511 sock = lttcomm_accept_unix_sock(client_socket);
2512 if (sock <= 0) {
2513 WARN("On accept");
2514 goto end;
2515 }
2516 ret = fcntl(sock, F_SETFL, O_NONBLOCK);
2517 if (ret < 0) {
2518 PERROR("fcntl O_NONBLOCK");
2519 goto end;
2520 }
2521
2522 /* This socket is not useful anymore. */
2523 ret = close(client_socket);
2524 if (ret < 0) {
2525 PERROR("close client_socket");
2526 }
2527 client_socket = -1;
2528
2529 /* update the polling structure to poll on the established socket */
2530 consumer_sockpoll[1].fd = sock;
2531 consumer_sockpoll[1].events = POLLIN | POLLPRI;
2532
2533 while (1) {
2534 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
2535 goto end;
2536 }
2537 DBG("Incoming command on sock");
2538 ret = lttng_consumer_recv_cmd(ctx, sock, consumer_sockpoll);
2539 if (ret == -ENOENT) {
2540 DBG("Received STOP command");
2541 goto end;
2542 }
2543 if (ret <= 0) {
2544 /*
2545 * This could simply be a session daemon quitting. Don't output
2546 * ERR() here.
2547 */
2548 DBG("Communication interrupted on command socket");
2549 goto end;
2550 }
2551 if (consumer_quit) {
2552 DBG("consumer_thread_receive_fds received quit from signal");
2553 goto end;
2554 }
2555 DBG("received fds on sock");
2556 }
2557 end:
2558 DBG("consumer_thread_receive_fds exiting");
2559
2560 /*
2561 * when all fds have hung up, the polling thread
2562 * can exit cleanly
2563 */
2564 consumer_quit = 1;
2565
2566 /*
2567 * Notify the data poll thread to poll back again and test the
2568 * consumer_quit state that we just set so to quit gracefully.
2569 */
2570 notify_thread_pipe(ctx->consumer_data_pipe[1]);
2571
2572 /* Cleaning up possibly open sockets. */
2573 if (sock >= 0) {
2574 ret = close(sock);
2575 if (ret < 0) {
2576 PERROR("close sock sessiond poll");
2577 }
2578 }
2579 if (client_socket >= 0) {
2580 ret = close(sock);
2581 if (ret < 0) {
2582 PERROR("close client_socket sessiond poll");
2583 }
2584 }
2585
2586 rcu_unregister_thread();
2587 return NULL;
2588 }
2589
2590 ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
2591 struct lttng_consumer_local_data *ctx)
2592 {
2593 ssize_t ret;
2594
2595 pthread_mutex_lock(&stream->lock);
2596
2597 switch (consumer_data.type) {
2598 case LTTNG_CONSUMER_KERNEL:
2599 ret = lttng_kconsumer_read_subbuffer(stream, ctx);
2600 break;
2601 case LTTNG_CONSUMER32_UST:
2602 case LTTNG_CONSUMER64_UST:
2603 ret = lttng_ustconsumer_read_subbuffer(stream, ctx);
2604 break;
2605 default:
2606 ERR("Unknown consumer_data type");
2607 assert(0);
2608 ret = -ENOSYS;
2609 break;
2610 }
2611
2612 pthread_mutex_unlock(&stream->lock);
2613 return ret;
2614 }
2615
2616 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream)
2617 {
2618 switch (consumer_data.type) {
2619 case LTTNG_CONSUMER_KERNEL:
2620 return lttng_kconsumer_on_recv_stream(stream);
2621 case LTTNG_CONSUMER32_UST:
2622 case LTTNG_CONSUMER64_UST:
2623 return lttng_ustconsumer_on_recv_stream(stream);
2624 default:
2625 ERR("Unknown consumer_data type");
2626 assert(0);
2627 return -ENOSYS;
2628 }
2629 }
2630
2631 /*
2632 * Allocate and set consumer data hash tables.
2633 */
2634 void lttng_consumer_init(void)
2635 {
2636 consumer_data.channel_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
2637 consumer_data.relayd_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
2638 consumer_data.stream_list_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
2639 }
2640
2641 /*
2642 * Process the ADD_RELAYD command receive by a consumer.
2643 *
2644 * This will create a relayd socket pair and add it to the relayd hash table.
2645 * The caller MUST acquire a RCU read side lock before calling it.
2646 */
2647 int consumer_add_relayd_socket(int net_seq_idx, int sock_type,
2648 struct lttng_consumer_local_data *ctx, int sock,
2649 struct pollfd *consumer_sockpoll, struct lttcomm_sock *relayd_sock)
2650 {
2651 int fd = -1, ret = -1;
2652 struct consumer_relayd_sock_pair *relayd;
2653
2654 DBG("Consumer adding relayd socket (idx: %d)", net_seq_idx);
2655
2656 /* Get relayd reference if exists. */
2657 relayd = consumer_find_relayd(net_seq_idx);
2658 if (relayd == NULL) {
2659 /* Not found. Allocate one. */
2660 relayd = consumer_allocate_relayd_sock_pair(net_seq_idx);
2661 if (relayd == NULL) {
2662 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
2663 goto error;
2664 }
2665 }
2666
2667 /* Poll on consumer socket. */
2668 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
2669 ret = -EINTR;
2670 goto error;
2671 }
2672
2673 /* Get relayd socket from session daemon */
2674 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
2675 if (ret != sizeof(fd)) {
2676 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
2677 ret = -1;
2678 fd = -1; /* Just in case it gets set with an invalid value. */
2679 goto error;
2680 }
2681
2682 /* Copy socket information and received FD */
2683 switch (sock_type) {
2684 case LTTNG_STREAM_CONTROL:
2685 /* Copy received lttcomm socket */
2686 lttcomm_copy_sock(&relayd->control_sock, relayd_sock);
2687 ret = lttcomm_create_sock(&relayd->control_sock);
2688 /* Immediately try to close the created socket if valid. */
2689 if (relayd->control_sock.fd >= 0) {
2690 if (close(relayd->control_sock.fd)) {
2691 PERROR("close relayd control socket");
2692 }
2693 }
2694 /* Handle create_sock error. */
2695 if (ret < 0) {
2696 goto error;
2697 }
2698
2699 /* Assign new file descriptor */
2700 relayd->control_sock.fd = fd;
2701 break;
2702 case LTTNG_STREAM_DATA:
2703 /* Copy received lttcomm socket */
2704 lttcomm_copy_sock(&relayd->data_sock, relayd_sock);
2705 ret = lttcomm_create_sock(&relayd->data_sock);
2706 /* Immediately try to close the created socket if valid. */
2707 if (relayd->data_sock.fd >= 0) {
2708 if (close(relayd->data_sock.fd)) {
2709 PERROR("close relayd data socket");
2710 }
2711 }
2712 /* Handle create_sock error. */
2713 if (ret < 0) {
2714 goto error;
2715 }
2716
2717 /* Assign new file descriptor */
2718 relayd->data_sock.fd = fd;
2719 break;
2720 default:
2721 ERR("Unknown relayd socket type (%d)", sock_type);
2722 goto error;
2723 }
2724
2725 DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
2726 sock_type == LTTNG_STREAM_CONTROL ? "control" : "data",
2727 relayd->net_seq_idx, fd);
2728
2729 /*
2730 * Add relayd socket pair to consumer data hashtable. If object already
2731 * exists or on error, the function gracefully returns.
2732 */
2733 add_relayd(relayd);
2734
2735 /* All good! */
2736 return 0;
2737
2738 error:
2739 /* Close received socket if valid. */
2740 if (fd >= 0) {
2741 if (close(fd)) {
2742 PERROR("close received socket");
2743 }
2744 }
2745 return ret;
2746 }
2747
2748 /*
2749 * Try to lock the stream mutex.
2750 *
2751 * On success, 1 is returned else 0 indicating that the mutex is NOT lock.
2752 */
2753 static int stream_try_lock(struct lttng_consumer_stream *stream)
2754 {
2755 int ret;
2756
2757 assert(stream);
2758
2759 /*
2760 * Try to lock the stream mutex. On failure, we know that the stream is
2761 * being used else where hence there is data still being extracted.
2762 */
2763 ret = pthread_mutex_trylock(&stream->lock);
2764 if (ret) {
2765 /* For both EBUSY and EINVAL error, the mutex is NOT locked. */
2766 ret = 0;
2767 goto end;
2768 }
2769
2770 ret = 1;
2771
2772 end:
2773 return ret;
2774 }
2775
2776 /*
2777 * Check if for a given session id there is still data needed to be extract
2778 * from the buffers.
2779 *
2780 * Return 1 if data is pending or else 0 meaning ready to be read.
2781 */
2782 int consumer_data_pending(uint64_t id)
2783 {
2784 int ret;
2785 struct lttng_ht_iter iter;
2786 struct lttng_ht *ht;
2787 struct lttng_consumer_stream *stream;
2788 struct consumer_relayd_sock_pair *relayd;
2789 int (*data_pending)(struct lttng_consumer_stream *);
2790
2791 DBG("Consumer data pending command on session id %" PRIu64, id);
2792
2793 rcu_read_lock();
2794 pthread_mutex_lock(&consumer_data.lock);
2795
2796 switch (consumer_data.type) {
2797 case LTTNG_CONSUMER_KERNEL:
2798 data_pending = lttng_kconsumer_data_pending;
2799 break;
2800 case LTTNG_CONSUMER32_UST:
2801 case LTTNG_CONSUMER64_UST:
2802 data_pending = lttng_ustconsumer_data_pending;
2803 break;
2804 default:
2805 ERR("Unknown consumer data type");
2806 assert(0);
2807 }
2808
2809 /* Ease our life a bit */
2810 ht = consumer_data.stream_list_ht;
2811
2812 cds_lfht_for_each_entry_duplicate(ht->ht,
2813 ht->hash_fct((void *)((unsigned long) id), lttng_ht_seed),
2814 ht->match_fct, (void *)((unsigned long) id),
2815 &iter.iter, stream, node_session_id.node) {
2816 /* If this call fails, the stream is being used hence data pending. */
2817 ret = stream_try_lock(stream);
2818 if (!ret) {
2819 goto data_not_pending;
2820 }
2821
2822 /*
2823 * A removed node from the hash table indicates that the stream has
2824 * been deleted thus having a guarantee that the buffers are closed
2825 * on the consumer side. However, data can still be transmitted
2826 * over the network so don't skip the relayd check.
2827 */
2828 ret = cds_lfht_is_node_deleted(&stream->node.node);
2829 if (!ret) {
2830 /* Check the stream if there is data in the buffers. */
2831 ret = data_pending(stream);
2832 if (ret == 1) {
2833 pthread_mutex_unlock(&stream->lock);
2834 goto data_not_pending;
2835 }
2836 }
2837
2838 /* Relayd check */
2839 if (stream->net_seq_idx != -1) {
2840 relayd = consumer_find_relayd(stream->net_seq_idx);
2841 if (!relayd) {
2842 /*
2843 * At this point, if the relayd object is not available for the
2844 * given stream, it is because the relayd is being cleaned up
2845 * so every stream associated with it (for a session id value)
2846 * are or will be marked for deletion hence no data pending.
2847 */
2848 pthread_mutex_unlock(&stream->lock);
2849 goto data_not_pending;
2850 }
2851
2852 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
2853 if (stream->metadata_flag) {
2854 ret = relayd_quiescent_control(&relayd->control_sock);
2855 } else {
2856 ret = relayd_data_pending(&relayd->control_sock,
2857 stream->relayd_stream_id, stream->next_net_seq_num);
2858 }
2859 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
2860 if (ret == 1) {
2861 pthread_mutex_unlock(&stream->lock);
2862 goto data_not_pending;
2863 }
2864 }
2865 pthread_mutex_unlock(&stream->lock);
2866 }
2867
2868 /*
2869 * Finding _no_ node in the hash table means that the stream(s) have been
2870 * removed thus data is guaranteed to be available for analysis from the
2871 * trace files. This is *only* true for local consumer and not network
2872 * streaming.
2873 */
2874
2875 /* Data is available to be read by a viewer. */
2876 pthread_mutex_unlock(&consumer_data.lock);
2877 rcu_read_unlock();
2878 return 0;
2879
2880 data_not_pending:
2881 /* Data is still being extracted from buffers. */
2882 pthread_mutex_unlock(&consumer_data.lock);
2883 rcu_read_unlock();
2884 return 1;
2885 }
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