Fix: add consumer wake up pipe to avoid race
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
1 /*
2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _GNU_SOURCE
20 #include <assert.h>
21 #include <lttng/ust-ctl.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/stat.h>
29 #include <sys/types.h>
30 #include <inttypes.h>
31 #include <unistd.h>
32 #include <urcu/list.h>
33 #include <signal.h>
34
35 #include <bin/lttng-consumerd/health-consumerd.h>
36 #include <common/common.h>
37 #include <common/sessiond-comm/sessiond-comm.h>
38 #include <common/relayd/relayd.h>
39 #include <common/compat/fcntl.h>
40 #include <common/consumer-metadata-cache.h>
41 #include <common/consumer-stream.h>
42 #include <common/consumer-timer.h>
43 #include <common/utils.h>
44 #include <common/index/index.h>
45
46 #include "ust-consumer.h"
47
48 extern struct lttng_consumer_global_data consumer_data;
49 extern int consumer_poll_timeout;
50 extern volatile int consumer_quit;
51
52 /*
53 * Free channel object and all streams associated with it. This MUST be used
54 * only and only if the channel has _NEVER_ been added to the global channel
55 * hash table.
56 */
57 static void destroy_channel(struct lttng_consumer_channel *channel)
58 {
59 struct lttng_consumer_stream *stream, *stmp;
60
61 assert(channel);
62
63 DBG("UST consumer cleaning stream list");
64
65 cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
66 send_node) {
67
68 health_code_update();
69
70 cds_list_del(&stream->send_node);
71 ustctl_destroy_stream(stream->ustream);
72 free(stream);
73 }
74
75 /*
76 * If a channel is available meaning that was created before the streams
77 * were, delete it.
78 */
79 if (channel->uchan) {
80 lttng_ustconsumer_del_channel(channel);
81 }
82 free(channel);
83 }
84
85 /*
86 * Add channel to internal consumer state.
87 *
88 * Returns 0 on success or else a negative value.
89 */
90 static int add_channel(struct lttng_consumer_channel *channel,
91 struct lttng_consumer_local_data *ctx)
92 {
93 int ret = 0;
94
95 assert(channel);
96 assert(ctx);
97
98 if (ctx->on_recv_channel != NULL) {
99 ret = ctx->on_recv_channel(channel);
100 if (ret == 0) {
101 ret = consumer_add_channel(channel, ctx);
102 } else if (ret < 0) {
103 /* Most likely an ENOMEM. */
104 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
105 goto error;
106 }
107 } else {
108 ret = consumer_add_channel(channel, ctx);
109 }
110
111 DBG("UST consumer channel added (key: %" PRIu64 ")", channel->key);
112
113 error:
114 return ret;
115 }
116
117 /*
118 * Allocate and return a consumer channel object.
119 */
120 static struct lttng_consumer_channel *allocate_channel(uint64_t session_id,
121 const char *pathname, const char *name, uid_t uid, gid_t gid,
122 uint64_t relayd_id, uint64_t key, enum lttng_event_output output,
123 uint64_t tracefile_size, uint64_t tracefile_count,
124 uint64_t session_id_per_pid, unsigned int monitor,
125 unsigned int live_timer_interval)
126 {
127 assert(pathname);
128 assert(name);
129
130 return consumer_allocate_channel(key, session_id, pathname, name, uid,
131 gid, relayd_id, output, tracefile_size,
132 tracefile_count, session_id_per_pid, monitor, live_timer_interval);
133 }
134
135 /*
136 * Allocate and return a consumer stream object. If _alloc_ret is not NULL, the
137 * error value if applicable is set in it else it is kept untouched.
138 *
139 * Return NULL on error else the newly allocated stream object.
140 */
141 static struct lttng_consumer_stream *allocate_stream(int cpu, int key,
142 struct lttng_consumer_channel *channel,
143 struct lttng_consumer_local_data *ctx, int *_alloc_ret)
144 {
145 int alloc_ret;
146 struct lttng_consumer_stream *stream = NULL;
147
148 assert(channel);
149 assert(ctx);
150
151 stream = consumer_allocate_stream(channel->key,
152 key,
153 LTTNG_CONSUMER_ACTIVE_STREAM,
154 channel->name,
155 channel->uid,
156 channel->gid,
157 channel->relayd_id,
158 channel->session_id,
159 cpu,
160 &alloc_ret,
161 channel->type,
162 channel->monitor);
163 if (stream == NULL) {
164 switch (alloc_ret) {
165 case -ENOENT:
166 /*
167 * We could not find the channel. Can happen if cpu hotplug
168 * happens while tearing down.
169 */
170 DBG3("Could not find channel");
171 break;
172 case -ENOMEM:
173 case -EINVAL:
174 default:
175 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
176 break;
177 }
178 goto error;
179 }
180
181 stream->chan = channel;
182
183 error:
184 if (_alloc_ret) {
185 *_alloc_ret = alloc_ret;
186 }
187 return stream;
188 }
189
190 /*
191 * Send the given stream pointer to the corresponding thread.
192 *
193 * Returns 0 on success else a negative value.
194 */
195 static int send_stream_to_thread(struct lttng_consumer_stream *stream,
196 struct lttng_consumer_local_data *ctx)
197 {
198 int ret;
199 struct lttng_pipe *stream_pipe;
200
201 /* Get the right pipe where the stream will be sent. */
202 if (stream->metadata_flag) {
203 ret = consumer_add_metadata_stream(stream);
204 if (ret) {
205 ERR("Consumer add metadata stream %" PRIu64 " failed.",
206 stream->key);
207 goto error;
208 }
209 stream_pipe = ctx->consumer_metadata_pipe;
210 } else {
211 ret = consumer_add_data_stream(stream);
212 if (ret) {
213 ERR("Consumer add stream %" PRIu64 " failed.",
214 stream->key);
215 goto error;
216 }
217 stream_pipe = ctx->consumer_data_pipe;
218 }
219
220 /*
221 * From this point on, the stream's ownership has been moved away from
222 * the channel and becomes globally visible.
223 */
224 stream->globally_visible = 1;
225
226 ret = lttng_pipe_write(stream_pipe, &stream, sizeof(stream));
227 if (ret < 0) {
228 ERR("Consumer write %s stream to pipe %d",
229 stream->metadata_flag ? "metadata" : "data",
230 lttng_pipe_get_writefd(stream_pipe));
231 if (stream->metadata_flag) {
232 consumer_del_stream_for_metadata(stream);
233 } else {
234 consumer_del_stream_for_data(stream);
235 }
236 }
237 error:
238 return ret;
239 }
240
241 /*
242 * Create streams for the given channel using liblttng-ust-ctl.
243 *
244 * Return 0 on success else a negative value.
245 */
246 static int create_ust_streams(struct lttng_consumer_channel *channel,
247 struct lttng_consumer_local_data *ctx)
248 {
249 int ret, cpu = 0;
250 struct ustctl_consumer_stream *ustream;
251 struct lttng_consumer_stream *stream;
252
253 assert(channel);
254 assert(ctx);
255
256 /*
257 * While a stream is available from ustctl. When NULL is returned, we've
258 * reached the end of the possible stream for the channel.
259 */
260 while ((ustream = ustctl_create_stream(channel->uchan, cpu))) {
261 int wait_fd;
262 int ust_metadata_pipe[2];
263
264 health_code_update();
265
266 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA && channel->monitor) {
267 ret = utils_create_pipe_cloexec_nonblock(ust_metadata_pipe);
268 if (ret < 0) {
269 ERR("Create ust metadata poll pipe");
270 goto error;
271 }
272 wait_fd = ust_metadata_pipe[0];
273 } else {
274 wait_fd = ustctl_stream_get_wait_fd(ustream);
275 }
276
277 /* Allocate consumer stream object. */
278 stream = allocate_stream(cpu, wait_fd, channel, ctx, &ret);
279 if (!stream) {
280 goto error_alloc;
281 }
282 stream->ustream = ustream;
283 /*
284 * Store it so we can save multiple function calls afterwards since
285 * this value is used heavily in the stream threads. This is UST
286 * specific so this is why it's done after allocation.
287 */
288 stream->wait_fd = wait_fd;
289
290 /*
291 * Increment channel refcount since the channel reference has now been
292 * assigned in the allocation process above.
293 */
294 if (stream->chan->monitor) {
295 uatomic_inc(&stream->chan->refcount);
296 }
297
298 /*
299 * Order is important this is why a list is used. On error, the caller
300 * should clean this list.
301 */
302 cds_list_add_tail(&stream->send_node, &channel->streams.head);
303
304 ret = ustctl_get_max_subbuf_size(stream->ustream,
305 &stream->max_sb_size);
306 if (ret < 0) {
307 ERR("ustctl_get_max_subbuf_size failed for stream %s",
308 stream->name);
309 goto error;
310 }
311
312 /* Do actions once stream has been received. */
313 if (ctx->on_recv_stream) {
314 ret = ctx->on_recv_stream(stream);
315 if (ret < 0) {
316 goto error;
317 }
318 }
319
320 DBG("UST consumer add stream %s (key: %" PRIu64 ") with relayd id %" PRIu64,
321 stream->name, stream->key, stream->relayd_stream_id);
322
323 /* Set next CPU stream. */
324 channel->streams.count = ++cpu;
325
326 /* Keep stream reference when creating metadata. */
327 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA) {
328 channel->metadata_stream = stream;
329 stream->ust_metadata_poll_pipe[0] = ust_metadata_pipe[0];
330 stream->ust_metadata_poll_pipe[1] = ust_metadata_pipe[1];
331 }
332 }
333
334 return 0;
335
336 error:
337 error_alloc:
338 return ret;
339 }
340
341 /*
342 * Create an UST channel with the given attributes and send it to the session
343 * daemon using the ust ctl API.
344 *
345 * Return 0 on success or else a negative value.
346 */
347 static int create_ust_channel(struct ustctl_consumer_channel_attr *attr,
348 struct ustctl_consumer_channel **chanp)
349 {
350 int ret;
351 struct ustctl_consumer_channel *channel;
352
353 assert(attr);
354 assert(chanp);
355
356 DBG3("Creating channel to ustctl with attr: [overwrite: %d, "
357 "subbuf_size: %" PRIu64 ", num_subbuf: %" PRIu64 ", "
358 "switch_timer_interval: %u, read_timer_interval: %u, "
359 "output: %d, type: %d", attr->overwrite, attr->subbuf_size,
360 attr->num_subbuf, attr->switch_timer_interval,
361 attr->read_timer_interval, attr->output, attr->type);
362
363 channel = ustctl_create_channel(attr);
364 if (!channel) {
365 ret = -1;
366 goto error_create;
367 }
368
369 *chanp = channel;
370
371 return 0;
372
373 error_create:
374 return ret;
375 }
376
377 /*
378 * Send a single given stream to the session daemon using the sock.
379 *
380 * Return 0 on success else a negative value.
381 */
382 static int send_sessiond_stream(int sock, struct lttng_consumer_stream *stream)
383 {
384 int ret;
385
386 assert(stream);
387 assert(sock >= 0);
388
389 DBG("UST consumer sending stream %" PRIu64 " to sessiond", stream->key);
390
391 /* Send stream to session daemon. */
392 ret = ustctl_send_stream_to_sessiond(sock, stream->ustream);
393 if (ret < 0) {
394 goto error;
395 }
396
397 error:
398 return ret;
399 }
400
401 /*
402 * Send channel to sessiond.
403 *
404 * Return 0 on success or else a negative value.
405 */
406 static int send_sessiond_channel(int sock,
407 struct lttng_consumer_channel *channel,
408 struct lttng_consumer_local_data *ctx, int *relayd_error)
409 {
410 int ret, ret_code = LTTCOMM_CONSUMERD_SUCCESS;
411 struct lttng_consumer_stream *stream;
412 uint64_t net_seq_idx = -1ULL;
413
414 assert(channel);
415 assert(ctx);
416 assert(sock >= 0);
417
418 DBG("UST consumer sending channel %s to sessiond", channel->name);
419
420 if (channel->relayd_id != (uint64_t) -1ULL) {
421 cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
422
423 health_code_update();
424
425 /* Try to send the stream to the relayd if one is available. */
426 ret = consumer_send_relayd_stream(stream, stream->chan->pathname);
427 if (ret < 0) {
428 /*
429 * Flag that the relayd was the problem here probably due to a
430 * communicaton error on the socket.
431 */
432 if (relayd_error) {
433 *relayd_error = 1;
434 }
435 ret_code = LTTNG_ERR_RELAYD_CONNECT_FAIL;
436 }
437 if (net_seq_idx == -1ULL) {
438 net_seq_idx = stream->net_seq_idx;
439 }
440 }
441 }
442
443 /* Inform sessiond that we are about to send channel and streams. */
444 ret = consumer_send_status_msg(sock, ret_code);
445 if (ret < 0 || ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
446 /*
447 * Either the session daemon is not responding or the relayd died so we
448 * stop now.
449 */
450 goto error;
451 }
452
453 /* Send channel to sessiond. */
454 ret = ustctl_send_channel_to_sessiond(sock, channel->uchan);
455 if (ret < 0) {
456 goto error;
457 }
458
459 ret = ustctl_channel_close_wakeup_fd(channel->uchan);
460 if (ret < 0) {
461 goto error;
462 }
463
464 /* The channel was sent successfully to the sessiond at this point. */
465 cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
466
467 health_code_update();
468
469 /* Send stream to session daemon. */
470 ret = send_sessiond_stream(sock, stream);
471 if (ret < 0) {
472 goto error;
473 }
474 }
475
476 /* Tell sessiond there is no more stream. */
477 ret = ustctl_send_stream_to_sessiond(sock, NULL);
478 if (ret < 0) {
479 goto error;
480 }
481
482 DBG("UST consumer NULL stream sent to sessiond");
483
484 return 0;
485
486 error:
487 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
488 ret = -1;
489 }
490 return ret;
491 }
492
493 /*
494 * Creates a channel and streams and add the channel it to the channel internal
495 * state. The created stream must ONLY be sent once the GET_CHANNEL command is
496 * received.
497 *
498 * Return 0 on success or else, a negative value is returned and the channel
499 * MUST be destroyed by consumer_del_channel().
500 */
501 static int ask_channel(struct lttng_consumer_local_data *ctx, int sock,
502 struct lttng_consumer_channel *channel,
503 struct ustctl_consumer_channel_attr *attr)
504 {
505 int ret;
506
507 assert(ctx);
508 assert(channel);
509 assert(attr);
510
511 /*
512 * This value is still used by the kernel consumer since for the kernel,
513 * the stream ownership is not IN the consumer so we need to have the
514 * number of left stream that needs to be initialized so we can know when
515 * to delete the channel (see consumer.c).
516 *
517 * As for the user space tracer now, the consumer creates and sends the
518 * stream to the session daemon which only sends them to the application
519 * once every stream of a channel is received making this value useless
520 * because we they will be added to the poll thread before the application
521 * receives them. This ensures that a stream can not hang up during
522 * initilization of a channel.
523 */
524 channel->nb_init_stream_left = 0;
525
526 /* The reply msg status is handled in the following call. */
527 ret = create_ust_channel(attr, &channel->uchan);
528 if (ret < 0) {
529 goto end;
530 }
531
532 channel->wait_fd = ustctl_channel_get_wait_fd(channel->uchan);
533
534 /*
535 * For the snapshots (no monitor), we create the metadata streams
536 * on demand, not during the channel creation.
537 */
538 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA && !channel->monitor) {
539 ret = 0;
540 goto end;
541 }
542
543 /* Open all streams for this channel. */
544 ret = create_ust_streams(channel, ctx);
545 if (ret < 0) {
546 goto end;
547 }
548
549 end:
550 return ret;
551 }
552
553 /*
554 * Send all stream of a channel to the right thread handling it.
555 *
556 * On error, return a negative value else 0 on success.
557 */
558 static int send_streams_to_thread(struct lttng_consumer_channel *channel,
559 struct lttng_consumer_local_data *ctx)
560 {
561 int ret = 0;
562 struct lttng_consumer_stream *stream, *stmp;
563
564 assert(channel);
565 assert(ctx);
566
567 /* Send streams to the corresponding thread. */
568 cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
569 send_node) {
570
571 health_code_update();
572
573 /* Sending the stream to the thread. */
574 ret = send_stream_to_thread(stream, ctx);
575 if (ret < 0) {
576 /*
577 * If we are unable to send the stream to the thread, there is
578 * a big problem so just stop everything.
579 */
580 /* Remove node from the channel stream list. */
581 cds_list_del(&stream->send_node);
582 goto error;
583 }
584
585 /* Remove node from the channel stream list. */
586 cds_list_del(&stream->send_node);
587
588 }
589
590 error:
591 return ret;
592 }
593
594 /*
595 * Flush channel's streams using the given key to retrieve the channel.
596 *
597 * Return 0 on success else an LTTng error code.
598 */
599 static int flush_channel(uint64_t chan_key)
600 {
601 int ret = 0;
602 struct lttng_consumer_channel *channel;
603 struct lttng_consumer_stream *stream;
604 struct lttng_ht *ht;
605 struct lttng_ht_iter iter;
606
607 DBG("UST consumer flush channel key %" PRIu64, chan_key);
608
609 rcu_read_lock();
610 channel = consumer_find_channel(chan_key);
611 if (!channel) {
612 ERR("UST consumer flush channel %" PRIu64 " not found", chan_key);
613 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
614 goto error;
615 }
616
617 ht = consumer_data.stream_per_chan_id_ht;
618
619 /* For each stream of the channel id, flush it. */
620 cds_lfht_for_each_entry_duplicate(ht->ht,
621 ht->hash_fct(&channel->key, lttng_ht_seed), ht->match_fct,
622 &channel->key, &iter.iter, stream, node_channel_id.node) {
623
624 health_code_update();
625
626 ustctl_flush_buffer(stream->ustream, 1);
627 }
628 error:
629 rcu_read_unlock();
630 return ret;
631 }
632
633 /*
634 * Close metadata stream wakeup_fd using the given key to retrieve the channel.
635 * RCU read side lock MUST be acquired before calling this function.
636 *
637 * Return 0 on success else an LTTng error code.
638 */
639 static int close_metadata(uint64_t chan_key)
640 {
641 int ret = 0;
642 struct lttng_consumer_channel *channel;
643
644 DBG("UST consumer close metadata key %" PRIu64, chan_key);
645
646 channel = consumer_find_channel(chan_key);
647 if (!channel) {
648 /*
649 * This is possible if the metadata thread has issue a delete because
650 * the endpoint point of the stream hung up. There is no way the
651 * session daemon can know about it thus use a DBG instead of an actual
652 * error.
653 */
654 DBG("UST consumer close metadata %" PRIu64 " not found", chan_key);
655 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
656 goto error;
657 }
658
659 pthread_mutex_lock(&consumer_data.lock);
660 pthread_mutex_lock(&channel->lock);
661
662 if (cds_lfht_is_node_deleted(&channel->node.node)) {
663 goto error_unlock;
664 }
665
666 lttng_ustconsumer_close_metadata(channel);
667
668 error_unlock:
669 pthread_mutex_unlock(&channel->lock);
670 pthread_mutex_unlock(&consumer_data.lock);
671 error:
672 return ret;
673 }
674
675 /*
676 * RCU read side lock MUST be acquired before calling this function.
677 *
678 * Return 0 on success else an LTTng error code.
679 */
680 static int setup_metadata(struct lttng_consumer_local_data *ctx, uint64_t key)
681 {
682 int ret;
683 struct lttng_consumer_channel *metadata;
684
685 DBG("UST consumer setup metadata key %" PRIu64, key);
686
687 metadata = consumer_find_channel(key);
688 if (!metadata) {
689 ERR("UST consumer push metadata %" PRIu64 " not found", key);
690 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
691 goto end;
692 }
693
694 /*
695 * In no monitor mode, the metadata channel has no stream(s) so skip the
696 * ownership transfer to the metadata thread.
697 */
698 if (!metadata->monitor) {
699 DBG("Metadata channel in no monitor");
700 ret = 0;
701 goto end;
702 }
703
704 /*
705 * Send metadata stream to relayd if one available. Availability is
706 * known if the stream is still in the list of the channel.
707 */
708 if (cds_list_empty(&metadata->streams.head)) {
709 ERR("Metadata channel key %" PRIu64 ", no stream available.", key);
710 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
711 goto error_no_stream;
712 }
713
714 /* Send metadata stream to relayd if needed. */
715 if (metadata->metadata_stream->net_seq_idx != (uint64_t) -1ULL) {
716 ret = consumer_send_relayd_stream(metadata->metadata_stream,
717 metadata->pathname);
718 if (ret < 0) {
719 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
720 goto error;
721 }
722 ret = consumer_send_relayd_streams_sent(
723 metadata->metadata_stream->net_seq_idx);
724 if (ret < 0) {
725 ret = LTTCOMM_CONSUMERD_RELAYD_FAIL;
726 goto error;
727 }
728 }
729
730 ret = send_streams_to_thread(metadata, ctx);
731 if (ret < 0) {
732 /*
733 * If we are unable to send the stream to the thread, there is
734 * a big problem so just stop everything.
735 */
736 ret = LTTCOMM_CONSUMERD_FATAL;
737 goto error;
738 }
739 /* List MUST be empty after or else it could be reused. */
740 assert(cds_list_empty(&metadata->streams.head));
741
742 ret = 0;
743 goto end;
744
745 error:
746 /*
747 * Delete metadata channel on error. At this point, the metadata stream can
748 * NOT be monitored by the metadata thread thus having the guarantee that
749 * the stream is still in the local stream list of the channel. This call
750 * will make sure to clean that list.
751 */
752 consumer_stream_destroy(metadata->metadata_stream, NULL);
753 cds_list_del(&metadata->metadata_stream->send_node);
754 metadata->metadata_stream = NULL;
755 error_no_stream:
756 end:
757 return ret;
758 }
759
760 /*
761 * Snapshot the whole metadata.
762 *
763 * Returns 0 on success, < 0 on error
764 */
765 static int snapshot_metadata(uint64_t key, char *path, uint64_t relayd_id,
766 struct lttng_consumer_local_data *ctx)
767 {
768 int ret = 0;
769 struct lttng_consumer_channel *metadata_channel;
770 struct lttng_consumer_stream *metadata_stream;
771
772 assert(path);
773 assert(ctx);
774
775 DBG("UST consumer snapshot metadata with key %" PRIu64 " at path %s",
776 key, path);
777
778 rcu_read_lock();
779
780 metadata_channel = consumer_find_channel(key);
781 if (!metadata_channel) {
782 ERR("UST snapshot metadata channel not found for key %" PRIu64,
783 key);
784 ret = -1;
785 goto error;
786 }
787 assert(!metadata_channel->monitor);
788
789 health_code_update();
790
791 /*
792 * Ask the sessiond if we have new metadata waiting and update the
793 * consumer metadata cache.
794 */
795 ret = lttng_ustconsumer_request_metadata(ctx, metadata_channel, 0, 1);
796 if (ret < 0) {
797 goto error;
798 }
799
800 health_code_update();
801
802 /*
803 * The metadata stream is NOT created in no monitor mode when the channel
804 * is created on a sessiond ask channel command.
805 */
806 ret = create_ust_streams(metadata_channel, ctx);
807 if (ret < 0) {
808 goto error;
809 }
810
811 metadata_stream = metadata_channel->metadata_stream;
812 assert(metadata_stream);
813
814 if (relayd_id != (uint64_t) -1ULL) {
815 metadata_stream->net_seq_idx = relayd_id;
816 ret = consumer_send_relayd_stream(metadata_stream, path);
817 if (ret < 0) {
818 goto error_stream;
819 }
820 } else {
821 ret = utils_create_stream_file(path, metadata_stream->name,
822 metadata_stream->chan->tracefile_size,
823 metadata_stream->tracefile_count_current,
824 metadata_stream->uid, metadata_stream->gid, NULL);
825 if (ret < 0) {
826 goto error_stream;
827 }
828 metadata_stream->out_fd = ret;
829 metadata_stream->tracefile_size_current = 0;
830 }
831
832 do {
833 health_code_update();
834
835 ret = lttng_consumer_read_subbuffer(metadata_stream, ctx);
836 if (ret < 0) {
837 goto error_stream;
838 }
839 } while (ret > 0);
840
841 error_stream:
842 /*
843 * Clean up the stream completly because the next snapshot will use a new
844 * metadata stream.
845 */
846 consumer_stream_destroy(metadata_stream, NULL);
847 cds_list_del(&metadata_stream->send_node);
848 metadata_channel->metadata_stream = NULL;
849
850 error:
851 rcu_read_unlock();
852 return ret;
853 }
854
855 /*
856 * Take a snapshot of all the stream of a channel.
857 *
858 * Returns 0 on success, < 0 on error
859 */
860 static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
861 uint64_t max_stream_size, struct lttng_consumer_local_data *ctx)
862 {
863 int ret;
864 unsigned use_relayd = 0;
865 unsigned long consumed_pos, produced_pos;
866 struct lttng_consumer_channel *channel;
867 struct lttng_consumer_stream *stream;
868
869 assert(path);
870 assert(ctx);
871
872 rcu_read_lock();
873
874 if (relayd_id != (uint64_t) -1ULL) {
875 use_relayd = 1;
876 }
877
878 channel = consumer_find_channel(key);
879 if (!channel) {
880 ERR("UST snapshot channel not found for key %" PRIu64, key);
881 ret = -1;
882 goto error;
883 }
884 assert(!channel->monitor);
885 DBG("UST consumer snapshot channel %" PRIu64, key);
886
887 cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
888
889 health_code_update();
890
891 /* Lock stream because we are about to change its state. */
892 pthread_mutex_lock(&stream->lock);
893 stream->net_seq_idx = relayd_id;
894
895 if (use_relayd) {
896 ret = consumer_send_relayd_stream(stream, path);
897 if (ret < 0) {
898 goto error_unlock;
899 }
900 } else {
901 ret = utils_create_stream_file(path, stream->name,
902 stream->chan->tracefile_size,
903 stream->tracefile_count_current,
904 stream->uid, stream->gid, NULL);
905 if (ret < 0) {
906 goto error_unlock;
907 }
908 stream->out_fd = ret;
909 stream->tracefile_size_current = 0;
910
911 DBG("UST consumer snapshot stream %s/%s (%" PRIu64 ")", path,
912 stream->name, stream->key);
913 }
914 if (relayd_id != -1ULL) {
915 ret = consumer_send_relayd_streams_sent(relayd_id);
916 if (ret < 0) {
917 goto error_unlock;
918 }
919 }
920
921 ustctl_flush_buffer(stream->ustream, 1);
922
923 ret = lttng_ustconsumer_take_snapshot(stream);
924 if (ret < 0) {
925 ERR("Taking UST snapshot");
926 goto error_unlock;
927 }
928
929 ret = lttng_ustconsumer_get_produced_snapshot(stream, &produced_pos);
930 if (ret < 0) {
931 ERR("Produced UST snapshot position");
932 goto error_unlock;
933 }
934
935 ret = lttng_ustconsumer_get_consumed_snapshot(stream, &consumed_pos);
936 if (ret < 0) {
937 ERR("Consumerd UST snapshot position");
938 goto error_unlock;
939 }
940
941 /*
942 * The original value is sent back if max stream size is larger than
943 * the possible size of the snapshot. Also, we asume that the session
944 * daemon should never send a maximum stream size that is lower than
945 * subbuffer size.
946 */
947 consumed_pos = consumer_get_consumed_maxsize(consumed_pos,
948 produced_pos, max_stream_size);
949
950 while (consumed_pos < produced_pos) {
951 ssize_t read_len;
952 unsigned long len, padded_len;
953
954 health_code_update();
955
956 DBG("UST consumer taking snapshot at pos %lu", consumed_pos);
957
958 ret = ustctl_get_subbuf(stream->ustream, &consumed_pos);
959 if (ret < 0) {
960 if (ret != -EAGAIN) {
961 PERROR("ustctl_get_subbuf snapshot");
962 goto error_close_stream;
963 }
964 DBG("UST consumer get subbuf failed. Skipping it.");
965 consumed_pos += stream->max_sb_size;
966 continue;
967 }
968
969 ret = ustctl_get_subbuf_size(stream->ustream, &len);
970 if (ret < 0) {
971 ERR("Snapshot ustctl_get_subbuf_size");
972 goto error_put_subbuf;
973 }
974
975 ret = ustctl_get_padded_subbuf_size(stream->ustream, &padded_len);
976 if (ret < 0) {
977 ERR("Snapshot ustctl_get_padded_subbuf_size");
978 goto error_put_subbuf;
979 }
980
981 read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
982 padded_len - len, NULL);
983 if (use_relayd) {
984 if (read_len != len) {
985 ret = -EPERM;
986 goto error_put_subbuf;
987 }
988 } else {
989 if (read_len != padded_len) {
990 ret = -EPERM;
991 goto error_put_subbuf;
992 }
993 }
994
995 ret = ustctl_put_subbuf(stream->ustream);
996 if (ret < 0) {
997 ERR("Snapshot ustctl_put_subbuf");
998 goto error_close_stream;
999 }
1000 consumed_pos += stream->max_sb_size;
1001 }
1002
1003 /* Simply close the stream so we can use it on the next snapshot. */
1004 consumer_stream_close(stream);
1005 pthread_mutex_unlock(&stream->lock);
1006 }
1007
1008 rcu_read_unlock();
1009 return 0;
1010
1011 error_put_subbuf:
1012 if (ustctl_put_subbuf(stream->ustream) < 0) {
1013 ERR("Snapshot ustctl_put_subbuf");
1014 }
1015 error_close_stream:
1016 consumer_stream_close(stream);
1017 error_unlock:
1018 pthread_mutex_unlock(&stream->lock);
1019 error:
1020 rcu_read_unlock();
1021 return ret;
1022 }
1023
1024 /*
1025 * Receive the metadata updates from the sessiond.
1026 */
1027 int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
1028 uint64_t len, struct lttng_consumer_channel *channel,
1029 int timer, int wait)
1030 {
1031 int ret, ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1032 char *metadata_str;
1033
1034 DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key, len);
1035
1036 metadata_str = zmalloc(len * sizeof(char));
1037 if (!metadata_str) {
1038 PERROR("zmalloc metadata string");
1039 ret_code = LTTCOMM_CONSUMERD_ENOMEM;
1040 goto end;
1041 }
1042
1043 health_code_update();
1044
1045 /* Receive metadata string. */
1046 ret = lttcomm_recv_unix_sock(sock, metadata_str, len);
1047 if (ret < 0) {
1048 /* Session daemon is dead so return gracefully. */
1049 ret_code = ret;
1050 goto end_free;
1051 }
1052
1053 health_code_update();
1054
1055 pthread_mutex_lock(&channel->metadata_cache->lock);
1056 ret = consumer_metadata_cache_write(channel, offset, len, metadata_str);
1057 if (ret < 0) {
1058 /* Unable to handle metadata. Notify session daemon. */
1059 ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
1060 /*
1061 * Skip metadata flush on write error since the offset and len might
1062 * not have been updated which could create an infinite loop below when
1063 * waiting for the metadata cache to be flushed.
1064 */
1065 pthread_mutex_unlock(&channel->metadata_cache->lock);
1066 goto end_free;
1067 }
1068 pthread_mutex_unlock(&channel->metadata_cache->lock);
1069
1070 if (!wait) {
1071 goto end_free;
1072 }
1073 while (consumer_metadata_cache_flushed(channel, offset + len, timer)) {
1074 DBG("Waiting for metadata to be flushed");
1075
1076 health_code_update();
1077
1078 usleep(DEFAULT_METADATA_AVAILABILITY_WAIT_TIME);
1079 }
1080
1081 end_free:
1082 free(metadata_str);
1083 end:
1084 return ret_code;
1085 }
1086
1087 /*
1088 * Receive command from session daemon and process it.
1089 *
1090 * Return 1 on success else a negative value or 0.
1091 */
1092 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
1093 int sock, struct pollfd *consumer_sockpoll)
1094 {
1095 ssize_t ret;
1096 enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1097 struct lttcomm_consumer_msg msg;
1098 struct lttng_consumer_channel *channel = NULL;
1099
1100 health_code_update();
1101
1102 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
1103 if (ret != sizeof(msg)) {
1104 DBG("Consumer received unexpected message size %zd (expects %zu)",
1105 ret, sizeof(msg));
1106 /*
1107 * The ret value might 0 meaning an orderly shutdown but this is ok
1108 * since the caller handles this.
1109 */
1110 if (ret > 0) {
1111 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
1112 ret = -1;
1113 }
1114 return ret;
1115 }
1116
1117 health_code_update();
1118
1119 /* deprecated */
1120 assert(msg.cmd_type != LTTNG_CONSUMER_STOP);
1121
1122 health_code_update();
1123
1124 /* relayd needs RCU read-side lock */
1125 rcu_read_lock();
1126
1127 switch (msg.cmd_type) {
1128 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
1129 {
1130 /* Session daemon status message are handled in the following call. */
1131 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
1132 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
1133 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
1134 msg.u.relayd_sock.relayd_session_id);
1135 goto end_nosignal;
1136 }
1137 case LTTNG_CONSUMER_DESTROY_RELAYD:
1138 {
1139 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
1140 struct consumer_relayd_sock_pair *relayd;
1141
1142 DBG("UST consumer destroying relayd %" PRIu64, index);
1143
1144 /* Get relayd reference if exists. */
1145 relayd = consumer_find_relayd(index);
1146 if (relayd == NULL) {
1147 DBG("Unable to find relayd %" PRIu64, index);
1148 ret_code = LTTNG_ERR_NO_CONSUMER;
1149 }
1150
1151 /*
1152 * Each relayd socket pair has a refcount of stream attached to it
1153 * which tells if the relayd is still active or not depending on the
1154 * refcount value.
1155 *
1156 * This will set the destroy flag of the relayd object and destroy it
1157 * if the refcount reaches zero when called.
1158 *
1159 * The destroy can happen either here or when a stream fd hangs up.
1160 */
1161 if (relayd) {
1162 consumer_flag_relayd_for_destroy(relayd);
1163 }
1164
1165 goto end_msg_sessiond;
1166 }
1167 case LTTNG_CONSUMER_UPDATE_STREAM:
1168 {
1169 rcu_read_unlock();
1170 return -ENOSYS;
1171 }
1172 case LTTNG_CONSUMER_DATA_PENDING:
1173 {
1174 int ret, is_data_pending;
1175 uint64_t id = msg.u.data_pending.session_id;
1176
1177 DBG("UST consumer data pending command for id %" PRIu64, id);
1178
1179 is_data_pending = consumer_data_pending(id);
1180
1181 /* Send back returned value to session daemon */
1182 ret = lttcomm_send_unix_sock(sock, &is_data_pending,
1183 sizeof(is_data_pending));
1184 if (ret < 0) {
1185 DBG("Error when sending the data pending ret code: %d", ret);
1186 goto error_fatal;
1187 }
1188
1189 /*
1190 * No need to send back a status message since the data pending
1191 * returned value is the response.
1192 */
1193 break;
1194 }
1195 case LTTNG_CONSUMER_ASK_CHANNEL_CREATION:
1196 {
1197 int ret;
1198 struct ustctl_consumer_channel_attr attr;
1199
1200 /* Create a plain object and reserve a channel key. */
1201 channel = allocate_channel(msg.u.ask_channel.session_id,
1202 msg.u.ask_channel.pathname, msg.u.ask_channel.name,
1203 msg.u.ask_channel.uid, msg.u.ask_channel.gid,
1204 msg.u.ask_channel.relayd_id, msg.u.ask_channel.key,
1205 (enum lttng_event_output) msg.u.ask_channel.output,
1206 msg.u.ask_channel.tracefile_size,
1207 msg.u.ask_channel.tracefile_count,
1208 msg.u.ask_channel.session_id_per_pid,
1209 msg.u.ask_channel.monitor,
1210 msg.u.ask_channel.live_timer_interval);
1211 if (!channel) {
1212 goto end_channel_error;
1213 }
1214
1215 /*
1216 * Assign UST application UID to the channel. This value is ignored for
1217 * per PID buffers. This is specific to UST thus setting this after the
1218 * allocation.
1219 */
1220 channel->ust_app_uid = msg.u.ask_channel.ust_app_uid;
1221
1222 /* Build channel attributes from received message. */
1223 attr.subbuf_size = msg.u.ask_channel.subbuf_size;
1224 attr.num_subbuf = msg.u.ask_channel.num_subbuf;
1225 attr.overwrite = msg.u.ask_channel.overwrite;
1226 attr.switch_timer_interval = msg.u.ask_channel.switch_timer_interval;
1227 attr.read_timer_interval = msg.u.ask_channel.read_timer_interval;
1228 attr.chan_id = msg.u.ask_channel.chan_id;
1229 memcpy(attr.uuid, msg.u.ask_channel.uuid, sizeof(attr.uuid));
1230
1231 /* Match channel buffer type to the UST abi. */
1232 switch (msg.u.ask_channel.output) {
1233 case LTTNG_EVENT_MMAP:
1234 default:
1235 attr.output = LTTNG_UST_MMAP;
1236 break;
1237 }
1238
1239 /* Translate and save channel type. */
1240 switch (msg.u.ask_channel.type) {
1241 case LTTNG_UST_CHAN_PER_CPU:
1242 channel->type = CONSUMER_CHANNEL_TYPE_DATA;
1243 attr.type = LTTNG_UST_CHAN_PER_CPU;
1244 /*
1245 * Set refcount to 1 for owner. Below, we will
1246 * pass ownership to the
1247 * consumer_thread_channel_poll() thread.
1248 */
1249 channel->refcount = 1;
1250 break;
1251 case LTTNG_UST_CHAN_METADATA:
1252 channel->type = CONSUMER_CHANNEL_TYPE_METADATA;
1253 attr.type = LTTNG_UST_CHAN_METADATA;
1254 break;
1255 default:
1256 assert(0);
1257 goto error_fatal;
1258 };
1259
1260 health_code_update();
1261
1262 ret = ask_channel(ctx, sock, channel, &attr);
1263 if (ret < 0) {
1264 goto end_channel_error;
1265 }
1266
1267 if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
1268 ret = consumer_metadata_cache_allocate(channel);
1269 if (ret < 0) {
1270 ERR("Allocating metadata cache");
1271 goto end_channel_error;
1272 }
1273 consumer_timer_switch_start(channel, attr.switch_timer_interval);
1274 attr.switch_timer_interval = 0;
1275 } else {
1276 consumer_timer_live_start(channel,
1277 msg.u.ask_channel.live_timer_interval);
1278 }
1279
1280 health_code_update();
1281
1282 /*
1283 * Add the channel to the internal state AFTER all streams were created
1284 * and successfully sent to session daemon. This way, all streams must
1285 * be ready before this channel is visible to the threads.
1286 * If add_channel succeeds, ownership of the channel is
1287 * passed to consumer_thread_channel_poll().
1288 */
1289 ret = add_channel(channel, ctx);
1290 if (ret < 0) {
1291 if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
1292 if (channel->switch_timer_enabled == 1) {
1293 consumer_timer_switch_stop(channel);
1294 }
1295 consumer_metadata_cache_destroy(channel);
1296 }
1297 if (channel->live_timer_enabled == 1) {
1298 consumer_timer_live_stop(channel);
1299 }
1300 goto end_channel_error;
1301 }
1302
1303 health_code_update();
1304
1305 /*
1306 * Channel and streams are now created. Inform the session daemon that
1307 * everything went well and should wait to receive the channel and
1308 * streams with ustctl API.
1309 */
1310 ret = consumer_send_status_channel(sock, channel);
1311 if (ret < 0) {
1312 /*
1313 * There is probably a problem on the socket.
1314 */
1315 goto error_fatal;
1316 }
1317
1318 break;
1319 }
1320 case LTTNG_CONSUMER_GET_CHANNEL:
1321 {
1322 int ret, relayd_err = 0;
1323 uint64_t key = msg.u.get_channel.key;
1324 struct lttng_consumer_channel *channel;
1325
1326 channel = consumer_find_channel(key);
1327 if (!channel) {
1328 ERR("UST consumer get channel key %" PRIu64 " not found", key);
1329 ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1330 goto end_msg_sessiond;
1331 }
1332
1333 health_code_update();
1334
1335 /* Send everything to sessiond. */
1336 ret = send_sessiond_channel(sock, channel, ctx, &relayd_err);
1337 if (ret < 0) {
1338 if (relayd_err) {
1339 /*
1340 * We were unable to send to the relayd the stream so avoid
1341 * sending back a fatal error to the thread since this is OK
1342 * and the consumer can continue its work. The above call
1343 * has sent the error status message to the sessiond.
1344 */
1345 goto end_nosignal;
1346 }
1347 /*
1348 * The communicaton was broken hence there is a bad state between
1349 * the consumer and sessiond so stop everything.
1350 */
1351 goto error_fatal;
1352 }
1353
1354 health_code_update();
1355
1356 /*
1357 * In no monitor mode, the streams ownership is kept inside the channel
1358 * so don't send them to the data thread.
1359 */
1360 if (!channel->monitor) {
1361 goto end_msg_sessiond;
1362 }
1363
1364 ret = send_streams_to_thread(channel, ctx);
1365 if (ret < 0) {
1366 /*
1367 * If we are unable to send the stream to the thread, there is
1368 * a big problem so just stop everything.
1369 */
1370 goto error_fatal;
1371 }
1372 /* List MUST be empty after or else it could be reused. */
1373 assert(cds_list_empty(&channel->streams.head));
1374 goto end_msg_sessiond;
1375 }
1376 case LTTNG_CONSUMER_DESTROY_CHANNEL:
1377 {
1378 uint64_t key = msg.u.destroy_channel.key;
1379
1380 /*
1381 * Only called if streams have not been sent to stream
1382 * manager thread. However, channel has been sent to
1383 * channel manager thread.
1384 */
1385 notify_thread_del_channel(ctx, key);
1386 goto end_msg_sessiond;
1387 }
1388 case LTTNG_CONSUMER_CLOSE_METADATA:
1389 {
1390 int ret;
1391
1392 ret = close_metadata(msg.u.close_metadata.key);
1393 if (ret != 0) {
1394 ret_code = ret;
1395 }
1396
1397 goto end_msg_sessiond;
1398 }
1399 case LTTNG_CONSUMER_FLUSH_CHANNEL:
1400 {
1401 int ret;
1402
1403 ret = flush_channel(msg.u.flush_channel.key);
1404 if (ret != 0) {
1405 ret_code = ret;
1406 }
1407
1408 goto end_msg_sessiond;
1409 }
1410 case LTTNG_CONSUMER_PUSH_METADATA:
1411 {
1412 int ret;
1413 uint64_t len = msg.u.push_metadata.len;
1414 uint64_t key = msg.u.push_metadata.key;
1415 uint64_t offset = msg.u.push_metadata.target_offset;
1416 struct lttng_consumer_channel *channel;
1417
1418 DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key,
1419 len);
1420
1421 channel = consumer_find_channel(key);
1422 if (!channel) {
1423 /*
1424 * This is possible if the metadata creation on the consumer side
1425 * is in flight vis-a-vis a concurrent push metadata from the
1426 * session daemon. Simply return that the channel failed and the
1427 * session daemon will handle that message correctly considering
1428 * that this race is acceptable thus the DBG() statement here.
1429 */
1430 DBG("UST consumer push metadata %" PRIu64 " not found", key);
1431 ret_code = LTTCOMM_CONSUMERD_CHANNEL_FAIL;
1432 goto end_msg_sessiond;
1433 }
1434
1435 health_code_update();
1436
1437 /* Tell session daemon we are ready to receive the metadata. */
1438 ret = consumer_send_status_msg(sock, LTTCOMM_CONSUMERD_SUCCESS);
1439 if (ret < 0) {
1440 /* Somehow, the session daemon is not responding anymore. */
1441 goto error_fatal;
1442 }
1443
1444 health_code_update();
1445
1446 /* Wait for more data. */
1447 health_poll_entry();
1448 ret = lttng_consumer_poll_socket(consumer_sockpoll);
1449 health_poll_exit();
1450 if (ret) {
1451 goto error_fatal;
1452 }
1453
1454 health_code_update();
1455
1456 ret = lttng_ustconsumer_recv_metadata(sock, key, offset,
1457 len, channel, 0, 1);
1458 if (ret < 0) {
1459 /* error receiving from sessiond */
1460 goto error_fatal;
1461 } else {
1462 ret_code = ret;
1463 goto end_msg_sessiond;
1464 }
1465 }
1466 case LTTNG_CONSUMER_SETUP_METADATA:
1467 {
1468 int ret;
1469
1470 ret = setup_metadata(ctx, msg.u.setup_metadata.key);
1471 if (ret) {
1472 ret_code = ret;
1473 }
1474 goto end_msg_sessiond;
1475 }
1476 case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
1477 {
1478 if (msg.u.snapshot_channel.metadata) {
1479 ret = snapshot_metadata(msg.u.snapshot_channel.key,
1480 msg.u.snapshot_channel.pathname,
1481 msg.u.snapshot_channel.relayd_id,
1482 ctx);
1483 if (ret < 0) {
1484 ERR("Snapshot metadata failed");
1485 ret_code = LTTNG_ERR_UST_META_FAIL;
1486 }
1487 } else {
1488 ret = snapshot_channel(msg.u.snapshot_channel.key,
1489 msg.u.snapshot_channel.pathname,
1490 msg.u.snapshot_channel.relayd_id,
1491 msg.u.snapshot_channel.max_stream_size,
1492 ctx);
1493 if (ret < 0) {
1494 ERR("Snapshot channel failed");
1495 ret_code = LTTNG_ERR_UST_CHAN_FAIL;
1496 }
1497 }
1498
1499 health_code_update();
1500 ret = consumer_send_status_msg(sock, ret_code);
1501 if (ret < 0) {
1502 /* Somehow, the session daemon is not responding anymore. */
1503 goto end_nosignal;
1504 }
1505 health_code_update();
1506 break;
1507 }
1508 default:
1509 break;
1510 }
1511
1512 end_nosignal:
1513 rcu_read_unlock();
1514
1515 health_code_update();
1516
1517 /*
1518 * Return 1 to indicate success since the 0 value can be a socket
1519 * shutdown during the recv() or send() call.
1520 */
1521 return 1;
1522
1523 end_msg_sessiond:
1524 /*
1525 * The returned value here is not useful since either way we'll return 1 to
1526 * the caller because the session daemon socket management is done
1527 * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1528 */
1529 ret = consumer_send_status_msg(sock, ret_code);
1530 if (ret < 0) {
1531 goto error_fatal;
1532 }
1533 rcu_read_unlock();
1534
1535 health_code_update();
1536
1537 return 1;
1538 end_channel_error:
1539 if (channel) {
1540 /*
1541 * Free channel here since no one has a reference to it. We don't
1542 * free after that because a stream can store this pointer.
1543 */
1544 destroy_channel(channel);
1545 }
1546 /* We have to send a status channel message indicating an error. */
1547 ret = consumer_send_status_channel(sock, NULL);
1548 if (ret < 0) {
1549 /* Stop everything if session daemon can not be notified. */
1550 goto error_fatal;
1551 }
1552 rcu_read_unlock();
1553
1554 health_code_update();
1555
1556 return 1;
1557 error_fatal:
1558 rcu_read_unlock();
1559 /* This will issue a consumer stop. */
1560 return -1;
1561 }
1562
1563 /*
1564 * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
1565 * compiled out, we isolate it in this library.
1566 */
1567 int lttng_ustctl_get_mmap_read_offset(struct lttng_consumer_stream *stream,
1568 unsigned long *off)
1569 {
1570 assert(stream);
1571 assert(stream->ustream);
1572
1573 return ustctl_get_mmap_read_offset(stream->ustream, off);
1574 }
1575
1576 /*
1577 * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
1578 * compiled out, we isolate it in this library.
1579 */
1580 void *lttng_ustctl_get_mmap_base(struct lttng_consumer_stream *stream)
1581 {
1582 assert(stream);
1583 assert(stream->ustream);
1584
1585 return ustctl_get_mmap_base(stream->ustream);
1586 }
1587
1588 /*
1589 * Take a snapshot for a specific fd
1590 *
1591 * Returns 0 on success, < 0 on error
1592 */
1593 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_stream *stream)
1594 {
1595 assert(stream);
1596 assert(stream->ustream);
1597
1598 return ustctl_snapshot(stream->ustream);
1599 }
1600
1601 /*
1602 * Get the produced position
1603 *
1604 * Returns 0 on success, < 0 on error
1605 */
1606 int lttng_ustconsumer_get_produced_snapshot(
1607 struct lttng_consumer_stream *stream, unsigned long *pos)
1608 {
1609 assert(stream);
1610 assert(stream->ustream);
1611 assert(pos);
1612
1613 return ustctl_snapshot_get_produced(stream->ustream, pos);
1614 }
1615
1616 /*
1617 * Get the consumed position
1618 *
1619 * Returns 0 on success, < 0 on error
1620 */
1621 int lttng_ustconsumer_get_consumed_snapshot(
1622 struct lttng_consumer_stream *stream, unsigned long *pos)
1623 {
1624 assert(stream);
1625 assert(stream->ustream);
1626 assert(pos);
1627
1628 return ustctl_snapshot_get_consumed(stream->ustream, pos);
1629 }
1630
1631 void lttng_ustconsumer_flush_buffer(struct lttng_consumer_stream *stream,
1632 int producer)
1633 {
1634 assert(stream);
1635 assert(stream->ustream);
1636
1637 ustctl_flush_buffer(stream->ustream, producer);
1638 }
1639
1640 int lttng_ustconsumer_get_current_timestamp(
1641 struct lttng_consumer_stream *stream, uint64_t *ts)
1642 {
1643 assert(stream);
1644 assert(stream->ustream);
1645 assert(ts);
1646
1647 return ustctl_get_current_timestamp(stream->ustream, ts);
1648 }
1649
1650 /*
1651 * Called when the stream signal the consumer that it has hang up.
1652 */
1653 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
1654 {
1655 assert(stream);
1656 assert(stream->ustream);
1657
1658 ustctl_flush_buffer(stream->ustream, 0);
1659 stream->hangup_flush_done = 1;
1660 }
1661
1662 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
1663 {
1664 assert(chan);
1665 assert(chan->uchan);
1666
1667 if (chan->switch_timer_enabled == 1) {
1668 consumer_timer_switch_stop(chan);
1669 }
1670 consumer_metadata_cache_destroy(chan);
1671 ustctl_destroy_channel(chan->uchan);
1672 }
1673
1674 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
1675 {
1676 assert(stream);
1677 assert(stream->ustream);
1678
1679 if (stream->chan->switch_timer_enabled == 1) {
1680 consumer_timer_switch_stop(stream->chan);
1681 }
1682 ustctl_destroy_stream(stream->ustream);
1683 }
1684
1685 int lttng_ustconsumer_get_wakeup_fd(struct lttng_consumer_stream *stream)
1686 {
1687 assert(stream);
1688 assert(stream->ustream);
1689
1690 return ustctl_stream_get_wakeup_fd(stream->ustream);
1691 }
1692
1693 int lttng_ustconsumer_close_wakeup_fd(struct lttng_consumer_stream *stream)
1694 {
1695 assert(stream);
1696 assert(stream->ustream);
1697
1698 return ustctl_stream_close_wakeup_fd(stream->ustream);
1699 }
1700
1701 /*
1702 * Populate index values of a UST stream. Values are set in big endian order.
1703 *
1704 * Return 0 on success or else a negative value.
1705 */
1706 static int get_index_values(struct ctf_packet_index *index,
1707 struct ustctl_consumer_stream *ustream)
1708 {
1709 int ret;
1710
1711 ret = ustctl_get_timestamp_begin(ustream, &index->timestamp_begin);
1712 if (ret < 0) {
1713 PERROR("ustctl_get_timestamp_begin");
1714 goto error;
1715 }
1716 index->timestamp_begin = htobe64(index->timestamp_begin);
1717
1718 ret = ustctl_get_timestamp_end(ustream, &index->timestamp_end);
1719 if (ret < 0) {
1720 PERROR("ustctl_get_timestamp_end");
1721 goto error;
1722 }
1723 index->timestamp_end = htobe64(index->timestamp_end);
1724
1725 ret = ustctl_get_events_discarded(ustream, &index->events_discarded);
1726 if (ret < 0) {
1727 PERROR("ustctl_get_events_discarded");
1728 goto error;
1729 }
1730 index->events_discarded = htobe64(index->events_discarded);
1731
1732 ret = ustctl_get_content_size(ustream, &index->content_size);
1733 if (ret < 0) {
1734 PERROR("ustctl_get_content_size");
1735 goto error;
1736 }
1737 index->content_size = htobe64(index->content_size);
1738
1739 ret = ustctl_get_packet_size(ustream, &index->packet_size);
1740 if (ret < 0) {
1741 PERROR("ustctl_get_packet_size");
1742 goto error;
1743 }
1744 index->packet_size = htobe64(index->packet_size);
1745
1746 ret = ustctl_get_stream_id(ustream, &index->stream_id);
1747 if (ret < 0) {
1748 PERROR("ustctl_get_stream_id");
1749 goto error;
1750 }
1751 index->stream_id = htobe64(index->stream_id);
1752
1753 error:
1754 return ret;
1755 }
1756
1757 /*
1758 * Write up to one packet from the metadata cache to the channel.
1759 *
1760 * Returns the number of bytes pushed in the cache, or a negative value
1761 * on error.
1762 */
1763 static
1764 int commit_one_metadata_packet(struct lttng_consumer_stream *stream)
1765 {
1766 ssize_t write_len;
1767 int ret;
1768
1769 pthread_mutex_lock(&stream->chan->metadata_cache->lock);
1770 if (stream->chan->metadata_cache->contiguous
1771 == stream->ust_metadata_pushed) {
1772 ret = 0;
1773 goto end;
1774 }
1775
1776 write_len = ustctl_write_one_packet_to_channel(stream->chan->uchan,
1777 &stream->chan->metadata_cache->data[stream->ust_metadata_pushed],
1778 stream->chan->metadata_cache->contiguous
1779 - stream->ust_metadata_pushed);
1780 assert(write_len != 0);
1781 if (write_len < 0) {
1782 ERR("Writing one metadata packet");
1783 ret = -1;
1784 goto end;
1785 }
1786 stream->ust_metadata_pushed += write_len;
1787
1788 assert(stream->chan->metadata_cache->contiguous >=
1789 stream->ust_metadata_pushed);
1790 ret = write_len;
1791
1792 end:
1793 pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
1794 return ret;
1795 }
1796
1797
1798 /*
1799 * Sync metadata meaning request them to the session daemon and snapshot to the
1800 * metadata thread can consumer them.
1801 *
1802 * Metadata stream lock MUST be acquired.
1803 *
1804 * Return 0 if new metadatda is available, EAGAIN if the metadata stream
1805 * is empty or a negative value on error.
1806 */
1807 int lttng_ustconsumer_sync_metadata(struct lttng_consumer_local_data *ctx,
1808 struct lttng_consumer_stream *metadata)
1809 {
1810 int ret;
1811 int retry = 0;
1812
1813 assert(ctx);
1814 assert(metadata);
1815
1816 /*
1817 * Request metadata from the sessiond, but don't wait for the flush
1818 * because we locked the metadata thread.
1819 */
1820 ret = lttng_ustconsumer_request_metadata(ctx, metadata->chan, 0, 0);
1821 if (ret < 0) {
1822 goto end;
1823 }
1824
1825 ret = commit_one_metadata_packet(metadata);
1826 if (ret <= 0) {
1827 goto end;
1828 } else if (ret > 0) {
1829 retry = 1;
1830 }
1831
1832 ustctl_flush_buffer(metadata->ustream, 1);
1833 ret = ustctl_snapshot(metadata->ustream);
1834 if (ret < 0) {
1835 if (errno != EAGAIN) {
1836 ERR("Sync metadata, taking UST snapshot");
1837 goto end;
1838 }
1839 DBG("No new metadata when syncing them.");
1840 /* No new metadata, exit. */
1841 ret = ENODATA;
1842 goto end;
1843 }
1844
1845 /*
1846 * After this flush, we still need to extract metadata.
1847 */
1848 if (retry) {
1849 ret = EAGAIN;
1850 }
1851
1852 end:
1853 return ret;
1854 }
1855
1856 /*
1857 * Return 0 on success else a negative value.
1858 */
1859 static int notify_if_more_data(struct lttng_consumer_stream *stream,
1860 struct lttng_consumer_local_data *ctx)
1861 {
1862 int ret;
1863 struct ustctl_consumer_stream *ustream;
1864
1865 assert(stream);
1866 assert(ctx);
1867
1868 ustream = stream->ustream;
1869
1870 /*
1871 * First, we are going to check if there is a new subbuffer available
1872 * before reading the stream wait_fd.
1873 */
1874 /* Get the next subbuffer */
1875 ret = ustctl_get_next_subbuf(ustream);
1876 if (ret) {
1877 /* No more data found, flag the stream. */
1878 stream->has_data = 0;
1879 ret = 0;
1880 goto end;
1881 }
1882
1883 ret = ustctl_put_next_subbuf(ustream);
1884 assert(!ret);
1885
1886 /* This stream still has data. Flag it and wake up the data thread. */
1887 stream->has_data = 1;
1888
1889 if (stream->monitor && !stream->hangup_flush_done && !ctx->has_wakeup) {
1890 ssize_t writelen;
1891
1892 writelen = lttng_pipe_write(ctx->consumer_wakeup_pipe, "!", 1);
1893 if (writelen < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
1894 ret = writelen;
1895 goto end;
1896 }
1897
1898 /* The wake up pipe has been notified. */
1899 ctx->has_wakeup = 1;
1900 }
1901 ret = 0;
1902
1903 end:
1904 return ret;
1905 }
1906
1907 /*
1908 * Read subbuffer from the given stream.
1909 *
1910 * Stream lock MUST be acquired.
1911 *
1912 * Return 0 on success else a negative value.
1913 */
1914 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
1915 struct lttng_consumer_local_data *ctx)
1916 {
1917 unsigned long len, subbuf_size, padding;
1918 int err, write_index = 1;
1919 long ret = 0;
1920 struct ustctl_consumer_stream *ustream;
1921 struct ctf_packet_index index;
1922
1923 assert(stream);
1924 assert(stream->ustream);
1925 assert(ctx);
1926
1927 DBG("In UST read_subbuffer (wait_fd: %d, name: %s)", stream->wait_fd,
1928 stream->name);
1929
1930 /* Ease our life for what's next. */
1931 ustream = stream->ustream;
1932
1933 /*
1934 * We can consume the 1 byte written into the wait_fd by UST. Don't trigger
1935 * error if we cannot read this one byte (read returns 0), or if the error
1936 * is EAGAIN or EWOULDBLOCK.
1937 *
1938 * This is only done when the stream is monitored by a thread, before the
1939 * flush is done after a hangup and if the stream is not flagged with data
1940 * since there might be nothing to consume in the wait fd but still have
1941 * data available flagged by the consumer wake up pipe.
1942 */
1943 if (stream->monitor && !stream->hangup_flush_done && !stream->has_data) {
1944 char dummy;
1945 ssize_t readlen;
1946
1947 readlen = lttng_read(stream->wait_fd, &dummy, 1);
1948 if (readlen < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
1949 ret = readlen;
1950 goto end;
1951 }
1952 }
1953
1954 retry:
1955 /* Get the next subbuffer */
1956 err = ustctl_get_next_subbuf(ustream);
1957 if (err != 0) {
1958 /*
1959 * Populate metadata info if the existing info has
1960 * already been read.
1961 */
1962 if (stream->metadata_flag) {
1963 ret = commit_one_metadata_packet(stream);
1964 if (ret <= 0) {
1965 goto end;
1966 }
1967 ustctl_flush_buffer(stream->ustream, 1);
1968 goto retry;
1969 }
1970
1971 ret = err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
1972 /*
1973 * This is a debug message even for single-threaded consumer,
1974 * because poll() have more relaxed criterions than get subbuf,
1975 * so get_subbuf may fail for short race windows where poll()
1976 * would issue wakeups.
1977 */
1978 DBG("Reserving sub buffer failed (everything is normal, "
1979 "it is due to concurrency) [ret: %d]", err);
1980 goto end;
1981 }
1982 assert(stream->chan->output == CONSUMER_CHANNEL_MMAP);
1983
1984 if (!stream->metadata_flag) {
1985 index.offset = htobe64(stream->out_fd_offset);
1986 ret = get_index_values(&index, ustream);
1987 if (ret < 0) {
1988 goto end;
1989 }
1990 } else {
1991 write_index = 0;
1992 }
1993
1994 /* Get the full padded subbuffer size */
1995 err = ustctl_get_padded_subbuf_size(ustream, &len);
1996 assert(err == 0);
1997
1998 /* Get subbuffer data size (without padding) */
1999 err = ustctl_get_subbuf_size(ustream, &subbuf_size);
2000 assert(err == 0);
2001
2002 /* Make sure we don't get a subbuffer size bigger than the padded */
2003 assert(len >= subbuf_size);
2004
2005 padding = len - subbuf_size;
2006 /* write the subbuffer to the tracefile */
2007 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding, &index);
2008 /*
2009 * The mmap operation should write subbuf_size amount of data when network
2010 * streaming or the full padding (len) size when we are _not_ streaming.
2011 */
2012 if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
2013 (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
2014 /*
2015 * Display the error but continue processing to try to release the
2016 * subbuffer. This is a DBG statement since any unexpected kill or
2017 * signal, the application gets unregistered, relayd gets closed or
2018 * anything that affects the buffer lifetime will trigger this error.
2019 * So, for the sake of the user, don't print this error since it can
2020 * happen and it is OK with the code flow.
2021 */
2022 DBG("Error writing to tracefile "
2023 "(ret: %ld != len: %lu != subbuf_size: %lu)",
2024 ret, len, subbuf_size);
2025 write_index = 0;
2026 }
2027 err = ustctl_put_next_subbuf(ustream);
2028 assert(err == 0);
2029
2030 /*
2031 * This will consumer the byte on the wait_fd if and only if there is not
2032 * next subbuffer to be acquired.
2033 */
2034 if (!stream->metadata_flag) {
2035 ret = notify_if_more_data(stream, ctx);
2036 if (ret < 0) {
2037 goto end;
2038 }
2039 }
2040
2041 /* Write index if needed. */
2042 if (!write_index) {
2043 goto end;
2044 }
2045
2046 if (stream->chan->live_timer_interval && !stream->metadata_flag) {
2047 /*
2048 * In live, block until all the metadata is sent.
2049 */
2050 err = consumer_stream_sync_metadata(ctx, stream->session_id);
2051 if (err < 0) {
2052 goto end;
2053 }
2054 }
2055
2056 assert(!stream->metadata_flag);
2057 err = consumer_stream_write_index(stream, &index);
2058 if (err < 0) {
2059 goto end;
2060 }
2061
2062 end:
2063 return ret;
2064 }
2065
2066 /*
2067 * Called when a stream is created.
2068 *
2069 * Return 0 on success or else a negative value.
2070 */
2071 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
2072 {
2073 int ret;
2074
2075 assert(stream);
2076
2077 /* Don't create anything if this is set for streaming. */
2078 if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor) {
2079 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
2080 stream->chan->tracefile_size, stream->tracefile_count_current,
2081 stream->uid, stream->gid, NULL);
2082 if (ret < 0) {
2083 goto error;
2084 }
2085 stream->out_fd = ret;
2086 stream->tracefile_size_current = 0;
2087
2088 if (!stream->metadata_flag) {
2089 ret = index_create_file(stream->chan->pathname,
2090 stream->name, stream->uid, stream->gid,
2091 stream->chan->tracefile_size,
2092 stream->tracefile_count_current);
2093 if (ret < 0) {
2094 goto error;
2095 }
2096 stream->index_fd = ret;
2097 }
2098 }
2099 ret = 0;
2100
2101 error:
2102 return ret;
2103 }
2104
2105 /*
2106 * Check if data is still being extracted from the buffers for a specific
2107 * stream. Consumer data lock MUST be acquired before calling this function
2108 * and the stream lock.
2109 *
2110 * Return 1 if the traced data are still getting read else 0 meaning that the
2111 * data is available for trace viewer reading.
2112 */
2113 int lttng_ustconsumer_data_pending(struct lttng_consumer_stream *stream)
2114 {
2115 int ret;
2116
2117 assert(stream);
2118 assert(stream->ustream);
2119
2120 DBG("UST consumer checking data pending");
2121
2122 if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
2123 ret = 0;
2124 goto end;
2125 }
2126
2127 if (stream->chan->type == CONSUMER_CHANNEL_TYPE_METADATA) {
2128 uint64_t contiguous, pushed;
2129
2130 /* Ease our life a bit. */
2131 contiguous = stream->chan->metadata_cache->contiguous;
2132 pushed = stream->ust_metadata_pushed;
2133
2134 /*
2135 * We can simply check whether all contiguously available data
2136 * has been pushed to the ring buffer, since the push operation
2137 * is performed within get_next_subbuf(), and because both
2138 * get_next_subbuf() and put_next_subbuf() are issued atomically
2139 * thanks to the stream lock within
2140 * lttng_ustconsumer_read_subbuffer(). This basically means that
2141 * whetnever ust_metadata_pushed is incremented, the associated
2142 * metadata has been consumed from the metadata stream.
2143 */
2144 DBG("UST consumer metadata pending check: contiguous %" PRIu64 " vs pushed %" PRIu64,
2145 contiguous, pushed);
2146 assert(((int64_t) contiguous - pushed) >= 0);
2147 if ((contiguous != pushed) ||
2148 (((int64_t) contiguous - pushed) > 0 || contiguous == 0)) {
2149 ret = 1; /* Data is pending */
2150 goto end;
2151 }
2152 } else {
2153 ret = ustctl_get_next_subbuf(stream->ustream);
2154 if (ret == 0) {
2155 /*
2156 * There is still data so let's put back this
2157 * subbuffer.
2158 */
2159 ret = ustctl_put_subbuf(stream->ustream);
2160 assert(ret == 0);
2161 ret = 1; /* Data is pending */
2162 goto end;
2163 }
2164 }
2165
2166 /* Data is NOT pending so ready to be read. */
2167 ret = 0;
2168
2169 end:
2170 return ret;
2171 }
2172
2173 /*
2174 * Stop a given metadata channel timer if enabled and close the wait fd which
2175 * is the poll pipe of the metadata stream.
2176 *
2177 * This MUST be called with the metadata channel acquired.
2178 */
2179 void lttng_ustconsumer_close_metadata(struct lttng_consumer_channel *metadata)
2180 {
2181 int ret;
2182
2183 assert(metadata);
2184 assert(metadata->type == CONSUMER_CHANNEL_TYPE_METADATA);
2185
2186 DBG("Closing metadata channel key %" PRIu64, metadata->key);
2187
2188 if (metadata->switch_timer_enabled == 1) {
2189 consumer_timer_switch_stop(metadata);
2190 }
2191
2192 if (!metadata->metadata_stream) {
2193 goto end;
2194 }
2195
2196 /*
2197 * Closing write side so the thread monitoring the stream wakes up if any
2198 * and clean the metadata stream.
2199 */
2200 if (metadata->metadata_stream->ust_metadata_poll_pipe[1] >= 0) {
2201 ret = close(metadata->metadata_stream->ust_metadata_poll_pipe[1]);
2202 if (ret < 0) {
2203 PERROR("closing metadata pipe write side");
2204 }
2205 metadata->metadata_stream->ust_metadata_poll_pipe[1] = -1;
2206 }
2207
2208 end:
2209 return;
2210 }
2211
2212 /*
2213 * Close every metadata stream wait fd of the metadata hash table. This
2214 * function MUST be used very carefully so not to run into a race between the
2215 * metadata thread handling streams and this function closing their wait fd.
2216 *
2217 * For UST, this is used when the session daemon hangs up. Its the metadata
2218 * producer so calling this is safe because we are assured that no state change
2219 * can occur in the metadata thread for the streams in the hash table.
2220 */
2221 void lttng_ustconsumer_close_all_metadata(struct lttng_ht *metadata_ht)
2222 {
2223 struct lttng_ht_iter iter;
2224 struct lttng_consumer_stream *stream;
2225
2226 assert(metadata_ht);
2227 assert(metadata_ht->ht);
2228
2229 DBG("UST consumer closing all metadata streams");
2230
2231 rcu_read_lock();
2232 cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream,
2233 node.node) {
2234
2235 health_code_update();
2236
2237 pthread_mutex_lock(&stream->chan->lock);
2238 lttng_ustconsumer_close_metadata(stream->chan);
2239 pthread_mutex_unlock(&stream->chan->lock);
2240
2241 }
2242 rcu_read_unlock();
2243 }
2244
2245 void lttng_ustconsumer_close_stream_wakeup(struct lttng_consumer_stream *stream)
2246 {
2247 int ret;
2248
2249 ret = ustctl_stream_close_wakeup_fd(stream->ustream);
2250 if (ret < 0) {
2251 ERR("Unable to close wakeup fd");
2252 }
2253 }
2254
2255 /*
2256 * Please refer to consumer-timer.c before adding any lock within this
2257 * function or any of its callees. Timers have a very strict locking
2258 * semantic with respect to teardown. Failure to respect this semantic
2259 * introduces deadlocks.
2260 */
2261 int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
2262 struct lttng_consumer_channel *channel, int timer, int wait)
2263 {
2264 struct lttcomm_metadata_request_msg request;
2265 struct lttcomm_consumer_msg msg;
2266 enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
2267 uint64_t len, key, offset;
2268 int ret;
2269
2270 assert(channel);
2271 assert(channel->metadata_cache);
2272
2273 memset(&request, 0, sizeof(request));
2274
2275 /* send the metadata request to sessiond */
2276 switch (consumer_data.type) {
2277 case LTTNG_CONSUMER64_UST:
2278 request.bits_per_long = 64;
2279 break;
2280 case LTTNG_CONSUMER32_UST:
2281 request.bits_per_long = 32;
2282 break;
2283 default:
2284 request.bits_per_long = 0;
2285 break;
2286 }
2287
2288 request.session_id = channel->session_id;
2289 request.session_id_per_pid = channel->session_id_per_pid;
2290 /*
2291 * Request the application UID here so the metadata of that application can
2292 * be sent back. The channel UID corresponds to the user UID of the session
2293 * used for the rights on the stream file(s).
2294 */
2295 request.uid = channel->ust_app_uid;
2296 request.key = channel->key;
2297
2298 DBG("Sending metadata request to sessiond, session id %" PRIu64
2299 ", per-pid %" PRIu64 ", app UID %u and channek key %" PRIu64,
2300 request.session_id, request.session_id_per_pid, request.uid,
2301 request.key);
2302
2303 pthread_mutex_lock(&ctx->metadata_socket_lock);
2304
2305 health_code_update();
2306
2307 ret = lttcomm_send_unix_sock(ctx->consumer_metadata_socket, &request,
2308 sizeof(request));
2309 if (ret < 0) {
2310 ERR("Asking metadata to sessiond");
2311 goto end;
2312 }
2313
2314 health_code_update();
2315
2316 /* Receive the metadata from sessiond */
2317 ret = lttcomm_recv_unix_sock(ctx->consumer_metadata_socket, &msg,
2318 sizeof(msg));
2319 if (ret != sizeof(msg)) {
2320 DBG("Consumer received unexpected message size %d (expects %zu)",
2321 ret, sizeof(msg));
2322 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
2323 /*
2324 * The ret value might 0 meaning an orderly shutdown but this is ok
2325 * since the caller handles this.
2326 */
2327 goto end;
2328 }
2329
2330 health_code_update();
2331
2332 if (msg.cmd_type == LTTNG_ERR_UND) {
2333 /* No registry found */
2334 (void) consumer_send_status_msg(ctx->consumer_metadata_socket,
2335 ret_code);
2336 ret = 0;
2337 goto end;
2338 } else if (msg.cmd_type != LTTNG_CONSUMER_PUSH_METADATA) {
2339 ERR("Unexpected cmd_type received %d", msg.cmd_type);
2340 ret = -1;
2341 goto end;
2342 }
2343
2344 len = msg.u.push_metadata.len;
2345 key = msg.u.push_metadata.key;
2346 offset = msg.u.push_metadata.target_offset;
2347
2348 assert(key == channel->key);
2349 if (len == 0) {
2350 DBG("No new metadata to receive for key %" PRIu64, key);
2351 }
2352
2353 health_code_update();
2354
2355 /* Tell session daemon we are ready to receive the metadata. */
2356 ret = consumer_send_status_msg(ctx->consumer_metadata_socket,
2357 LTTCOMM_CONSUMERD_SUCCESS);
2358 if (ret < 0 || len == 0) {
2359 /*
2360 * Somehow, the session daemon is not responding anymore or there is
2361 * nothing to receive.
2362 */
2363 goto end;
2364 }
2365
2366 health_code_update();
2367
2368 ret = lttng_ustconsumer_recv_metadata(ctx->consumer_metadata_socket,
2369 key, offset, len, channel, timer, wait);
2370 if (ret >= 0) {
2371 /*
2372 * Only send the status msg if the sessiond is alive meaning a positive
2373 * ret code.
2374 */
2375 (void) consumer_send_status_msg(ctx->consumer_metadata_socket, ret);
2376 }
2377 ret = 0;
2378
2379 end:
2380 health_code_update();
2381
2382 pthread_mutex_unlock(&ctx->metadata_socket_lock);
2383 return ret;
2384 }
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