6a692b9ba5a8bffd7826bd164dfc3f1de9f8c9df
[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 <common/common.h>
36 #include <common/sessiond-comm/sessiond-comm.h>
37 #include <common/relayd/relayd.h>
38 #include <common/compat/fcntl.h>
39 #include <common/consumer-metadata-cache.h>
40 #include <common/consumer-stream.h>
41 #include <common/consumer-timer.h>
42 #include <common/utils.h>
43
44 #include "ust-consumer.h"
45
46 extern struct lttng_consumer_global_data consumer_data;
47 extern int consumer_poll_timeout;
48 extern volatile int consumer_quit;
49
50 /*
51 * Free channel object and all streams associated with it. This MUST be used
52 * only and only if the channel has _NEVER_ been added to the global channel
53 * hash table.
54 */
55 static void destroy_channel(struct lttng_consumer_channel *channel)
56 {
57 struct lttng_consumer_stream *stream, *stmp;
58
59 assert(channel);
60
61 DBG("UST consumer cleaning stream list");
62
63 cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
64 send_node) {
65 cds_list_del(&stream->send_node);
66 ustctl_destroy_stream(stream->ustream);
67 free(stream);
68 }
69
70 /*
71 * If a channel is available meaning that was created before the streams
72 * were, delete it.
73 */
74 if (channel->uchan) {
75 lttng_ustconsumer_del_channel(channel);
76 }
77 free(channel);
78 }
79
80 /*
81 * Add channel to internal consumer state.
82 *
83 * Returns 0 on success or else a negative value.
84 */
85 static int add_channel(struct lttng_consumer_channel *channel,
86 struct lttng_consumer_local_data *ctx)
87 {
88 int ret = 0;
89
90 assert(channel);
91 assert(ctx);
92
93 if (ctx->on_recv_channel != NULL) {
94 ret = ctx->on_recv_channel(channel);
95 if (ret == 0) {
96 ret = consumer_add_channel(channel, ctx);
97 } else if (ret < 0) {
98 /* Most likely an ENOMEM. */
99 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
100 goto error;
101 }
102 } else {
103 ret = consumer_add_channel(channel, ctx);
104 }
105
106 DBG("UST consumer channel added (key: %" PRIu64 ")", channel->key);
107
108 error:
109 return ret;
110 }
111
112 /*
113 * Allocate and return a consumer channel object.
114 */
115 static struct lttng_consumer_channel *allocate_channel(uint64_t session_id,
116 const char *pathname, const char *name, uid_t uid, gid_t gid,
117 uint64_t relayd_id, uint64_t key, enum lttng_event_output output,
118 uint64_t tracefile_size, uint64_t tracefile_count,
119 uint64_t session_id_per_pid, unsigned int monitor)
120 {
121 assert(pathname);
122 assert(name);
123
124 return consumer_allocate_channel(key, session_id, pathname, name, uid,
125 gid, relayd_id, output, tracefile_size,
126 tracefile_count, session_id_per_pid, monitor);
127 }
128
129 /*
130 * Allocate and return a consumer stream object. If _alloc_ret is not NULL, the
131 * error value if applicable is set in it else it is kept untouched.
132 *
133 * Return NULL on error else the newly allocated stream object.
134 */
135 static struct lttng_consumer_stream *allocate_stream(int cpu, int key,
136 struct lttng_consumer_channel *channel,
137 struct lttng_consumer_local_data *ctx, int *_alloc_ret)
138 {
139 int alloc_ret;
140 struct lttng_consumer_stream *stream = NULL;
141
142 assert(channel);
143 assert(ctx);
144
145 stream = consumer_allocate_stream(channel->key,
146 key,
147 LTTNG_CONSUMER_ACTIVE_STREAM,
148 channel->name,
149 channel->uid,
150 channel->gid,
151 channel->relayd_id,
152 channel->session_id,
153 cpu,
154 &alloc_ret,
155 channel->type,
156 channel->monitor);
157 if (stream == NULL) {
158 switch (alloc_ret) {
159 case -ENOENT:
160 /*
161 * We could not find the channel. Can happen if cpu hotplug
162 * happens while tearing down.
163 */
164 DBG3("Could not find channel");
165 break;
166 case -ENOMEM:
167 case -EINVAL:
168 default:
169 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
170 break;
171 }
172 goto error;
173 }
174
175 stream->chan = channel;
176
177 error:
178 if (_alloc_ret) {
179 *_alloc_ret = alloc_ret;
180 }
181 return stream;
182 }
183
184 /*
185 * Send the given stream pointer to the corresponding thread.
186 *
187 * Returns 0 on success else a negative value.
188 */
189 static int send_stream_to_thread(struct lttng_consumer_stream *stream,
190 struct lttng_consumer_local_data *ctx)
191 {
192 int ret;
193 struct lttng_pipe *stream_pipe;
194
195 /* Get the right pipe where the stream will be sent. */
196 if (stream->metadata_flag) {
197 ret = consumer_add_metadata_stream(stream);
198 if (ret) {
199 ERR("Consumer add metadata stream %" PRIu64 " failed.",
200 stream->key);
201 goto error;
202 }
203 stream_pipe = ctx->consumer_metadata_pipe;
204 } else {
205 ret = consumer_add_data_stream(stream);
206 if (ret) {
207 ERR("Consumer add stream %" PRIu64 " failed.",
208 stream->key);
209 goto error;
210 }
211 stream_pipe = ctx->consumer_data_pipe;
212 }
213
214 /*
215 * From this point on, the stream's ownership has been moved away from
216 * the channel and becomes globally visible.
217 */
218 stream->globally_visible = 1;
219
220 ret = lttng_pipe_write(stream_pipe, &stream, sizeof(stream));
221 if (ret < 0) {
222 ERR("Consumer write %s stream to pipe %d",
223 stream->metadata_flag ? "metadata" : "data",
224 lttng_pipe_get_writefd(stream_pipe));
225 if (stream->metadata_flag) {
226 consumer_del_stream_for_metadata(stream);
227 } else {
228 consumer_del_stream_for_data(stream);
229 }
230 }
231 error:
232 return ret;
233 }
234
235 /*
236 * Create streams for the given channel using liblttng-ust-ctl.
237 *
238 * Return 0 on success else a negative value.
239 */
240 static int create_ust_streams(struct lttng_consumer_channel *channel,
241 struct lttng_consumer_local_data *ctx)
242 {
243 int ret, cpu = 0;
244 struct ustctl_consumer_stream *ustream;
245 struct lttng_consumer_stream *stream;
246
247 assert(channel);
248 assert(ctx);
249
250 /*
251 * While a stream is available from ustctl. When NULL is returned, we've
252 * reached the end of the possible stream for the channel.
253 */
254 while ((ustream = ustctl_create_stream(channel->uchan, cpu))) {
255 int wait_fd;
256 int ust_metadata_pipe[2];
257
258 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA && channel->monitor) {
259 ret = utils_create_pipe_cloexec_nonblock(ust_metadata_pipe);
260 if (ret < 0) {
261 ERR("Create ust metadata poll pipe");
262 goto error;
263 }
264 wait_fd = ust_metadata_pipe[0];
265 } else {
266 wait_fd = ustctl_stream_get_wait_fd(ustream);
267 }
268
269 /* Allocate consumer stream object. */
270 stream = allocate_stream(cpu, wait_fd, channel, ctx, &ret);
271 if (!stream) {
272 goto error_alloc;
273 }
274 stream->ustream = ustream;
275 /*
276 * Store it so we can save multiple function calls afterwards since
277 * this value is used heavily in the stream threads. This is UST
278 * specific so this is why it's done after allocation.
279 */
280 stream->wait_fd = wait_fd;
281
282 /*
283 * Increment channel refcount since the channel reference has now been
284 * assigned in the allocation process above.
285 */
286 if (stream->chan->monitor) {
287 uatomic_inc(&stream->chan->refcount);
288 }
289
290 /*
291 * Order is important this is why a list is used. On error, the caller
292 * should clean this list.
293 */
294 cds_list_add_tail(&stream->send_node, &channel->streams.head);
295
296 ret = ustctl_get_max_subbuf_size(stream->ustream,
297 &stream->max_sb_size);
298 if (ret < 0) {
299 ERR("ustctl_get_max_subbuf_size failed for stream %s",
300 stream->name);
301 goto error;
302 }
303
304 /* Do actions once stream has been received. */
305 if (ctx->on_recv_stream) {
306 ret = ctx->on_recv_stream(stream);
307 if (ret < 0) {
308 goto error;
309 }
310 }
311
312 DBG("UST consumer add stream %s (key: %" PRIu64 ") with relayd id %" PRIu64,
313 stream->name, stream->key, stream->relayd_stream_id);
314
315 /* Set next CPU stream. */
316 channel->streams.count = ++cpu;
317
318 /* Keep stream reference when creating metadata. */
319 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA) {
320 channel->metadata_stream = stream;
321 stream->ust_metadata_poll_pipe[0] = ust_metadata_pipe[0];
322 stream->ust_metadata_poll_pipe[1] = ust_metadata_pipe[1];
323 }
324 }
325
326 return 0;
327
328 error:
329 error_alloc:
330 return ret;
331 }
332
333 /*
334 * Create an UST channel with the given attributes and send it to the session
335 * daemon using the ust ctl API.
336 *
337 * Return 0 on success or else a negative value.
338 */
339 static int create_ust_channel(struct ustctl_consumer_channel_attr *attr,
340 struct ustctl_consumer_channel **chanp)
341 {
342 int ret;
343 struct ustctl_consumer_channel *channel;
344
345 assert(attr);
346 assert(chanp);
347
348 DBG3("Creating channel to ustctl with attr: [overwrite: %d, "
349 "subbuf_size: %" PRIu64 ", num_subbuf: %" PRIu64 ", "
350 "switch_timer_interval: %u, read_timer_interval: %u, "
351 "output: %d, type: %d", attr->overwrite, attr->subbuf_size,
352 attr->num_subbuf, attr->switch_timer_interval,
353 attr->read_timer_interval, attr->output, attr->type);
354
355 channel = ustctl_create_channel(attr);
356 if (!channel) {
357 ret = -1;
358 goto error_create;
359 }
360
361 *chanp = channel;
362
363 return 0;
364
365 error_create:
366 return ret;
367 }
368
369 /*
370 * Send a single given stream to the session daemon using the sock.
371 *
372 * Return 0 on success else a negative value.
373 */
374 static int send_sessiond_stream(int sock, struct lttng_consumer_stream *stream)
375 {
376 int ret;
377
378 assert(stream);
379 assert(sock >= 0);
380
381 DBG("UST consumer sending stream %" PRIu64 " to sessiond", stream->key);
382
383 /* Send stream to session daemon. */
384 ret = ustctl_send_stream_to_sessiond(sock, stream->ustream);
385 if (ret < 0) {
386 goto error;
387 }
388
389 error:
390 return ret;
391 }
392
393 /*
394 * Send channel to sessiond.
395 *
396 * Return 0 on success or else a negative value.
397 */
398 static int send_sessiond_channel(int sock,
399 struct lttng_consumer_channel *channel,
400 struct lttng_consumer_local_data *ctx, int *relayd_error)
401 {
402 int ret, ret_code = LTTNG_OK;
403 struct lttng_consumer_stream *stream;
404
405 assert(channel);
406 assert(ctx);
407 assert(sock >= 0);
408
409 DBG("UST consumer sending channel %s to sessiond", channel->name);
410
411 if (channel->relayd_id != (uint64_t) -1ULL) {
412 cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
413 /* Try to send the stream to the relayd if one is available. */
414 ret = consumer_send_relayd_stream(stream, stream->chan->pathname);
415 if (ret < 0) {
416 /*
417 * Flag that the relayd was the problem here probably due to a
418 * communicaton error on the socket.
419 */
420 if (relayd_error) {
421 *relayd_error = 1;
422 }
423 ret_code = LTTNG_ERR_RELAYD_CONNECT_FAIL;
424 }
425 }
426 }
427
428 /* Inform sessiond that we are about to send channel and streams. */
429 ret = consumer_send_status_msg(sock, ret_code);
430 if (ret < 0 || ret_code != LTTNG_OK) {
431 /*
432 * Either the session daemon is not responding or the relayd died so we
433 * stop now.
434 */
435 goto error;
436 }
437
438 /* Send channel to sessiond. */
439 ret = ustctl_send_channel_to_sessiond(sock, channel->uchan);
440 if (ret < 0) {
441 goto error;
442 }
443
444 ret = ustctl_channel_close_wakeup_fd(channel->uchan);
445 if (ret < 0) {
446 goto error;
447 }
448
449 /* The channel was sent successfully to the sessiond at this point. */
450 cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
451 /* Send stream to session daemon. */
452 ret = send_sessiond_stream(sock, stream);
453 if (ret < 0) {
454 goto error;
455 }
456 }
457
458 /* Tell sessiond there is no more stream. */
459 ret = ustctl_send_stream_to_sessiond(sock, NULL);
460 if (ret < 0) {
461 goto error;
462 }
463
464 DBG("UST consumer NULL stream sent to sessiond");
465
466 return 0;
467
468 error:
469 if (ret_code != LTTNG_OK) {
470 ret = -1;
471 }
472 return ret;
473 }
474
475 /*
476 * Creates a channel and streams and add the channel it to the channel internal
477 * state. The created stream must ONLY be sent once the GET_CHANNEL command is
478 * received.
479 *
480 * Return 0 on success or else, a negative value is returned and the channel
481 * MUST be destroyed by consumer_del_channel().
482 */
483 static int ask_channel(struct lttng_consumer_local_data *ctx, int sock,
484 struct lttng_consumer_channel *channel,
485 struct ustctl_consumer_channel_attr *attr)
486 {
487 int ret;
488
489 assert(ctx);
490 assert(channel);
491 assert(attr);
492
493 /*
494 * This value is still used by the kernel consumer since for the kernel,
495 * the stream ownership is not IN the consumer so we need to have the
496 * number of left stream that needs to be initialized so we can know when
497 * to delete the channel (see consumer.c).
498 *
499 * As for the user space tracer now, the consumer creates and sends the
500 * stream to the session daemon which only sends them to the application
501 * once every stream of a channel is received making this value useless
502 * because we they will be added to the poll thread before the application
503 * receives them. This ensures that a stream can not hang up during
504 * initilization of a channel.
505 */
506 channel->nb_init_stream_left = 0;
507
508 /* The reply msg status is handled in the following call. */
509 ret = create_ust_channel(attr, &channel->uchan);
510 if (ret < 0) {
511 goto end;
512 }
513
514 channel->wait_fd = ustctl_channel_get_wait_fd(channel->uchan);
515
516 /*
517 * For the snapshots (no monitor), we create the metadata streams
518 * on demand, not during the channel creation.
519 */
520 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA && !channel->monitor) {
521 ret = 0;
522 goto end;
523 }
524
525 /* Open all streams for this channel. */
526 ret = create_ust_streams(channel, ctx);
527 if (ret < 0) {
528 goto end;
529 }
530
531 end:
532 return ret;
533 }
534
535 /*
536 * Send all stream of a channel to the right thread handling it.
537 *
538 * On error, return a negative value else 0 on success.
539 */
540 static int send_streams_to_thread(struct lttng_consumer_channel *channel,
541 struct lttng_consumer_local_data *ctx)
542 {
543 int ret = 0;
544 struct lttng_consumer_stream *stream, *stmp;
545
546 assert(channel);
547 assert(ctx);
548
549 /* Send streams to the corresponding thread. */
550 cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
551 send_node) {
552 /* Sending the stream to the thread. */
553 ret = send_stream_to_thread(stream, ctx);
554 if (ret < 0) {
555 /*
556 * If we are unable to send the stream to the thread, there is
557 * a big problem so just stop everything.
558 */
559 /* Remove node from the channel stream list. */
560 cds_list_del(&stream->send_node);
561 goto error;
562 }
563
564 /* Remove node from the channel stream list. */
565 cds_list_del(&stream->send_node);
566
567 }
568
569 error:
570 return ret;
571 }
572
573 /*
574 * Flush channel's streams using the given key to retrieve the channel.
575 *
576 * Return 0 on success else an LTTng error code.
577 */
578 static int flush_channel(uint64_t chan_key)
579 {
580 int ret = 0;
581 struct lttng_consumer_channel *channel;
582 struct lttng_consumer_stream *stream;
583 struct lttng_ht *ht;
584 struct lttng_ht_iter iter;
585
586 DBG("UST consumer flush channel key %" PRIu64, chan_key);
587
588 rcu_read_lock();
589 channel = consumer_find_channel(chan_key);
590 if (!channel) {
591 ERR("UST consumer flush channel %" PRIu64 " not found", chan_key);
592 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
593 goto error;
594 }
595
596 ht = consumer_data.stream_per_chan_id_ht;
597
598 /* For each stream of the channel id, flush it. */
599 cds_lfht_for_each_entry_duplicate(ht->ht,
600 ht->hash_fct(&channel->key, lttng_ht_seed), ht->match_fct,
601 &channel->key, &iter.iter, stream, node_channel_id.node) {
602 ustctl_flush_buffer(stream->ustream, 1);
603 }
604 error:
605 rcu_read_unlock();
606 return ret;
607 }
608 /*
609 * Close metadata stream wakeup_fd using the given key to retrieve the channel.
610 * RCU read side lock MUST be acquired before calling this function.
611 *
612 * NOTE: This function does NOT take any channel nor stream lock.
613 *
614 * Return 0 on success else LTTng error code.
615 */
616 static int _close_metadata(struct lttng_consumer_channel *channel)
617 {
618 int ret = LTTNG_OK;
619
620 assert(channel);
621 assert(channel->type == CONSUMER_CHANNEL_TYPE_METADATA);
622
623 if (channel->switch_timer_enabled == 1) {
624 DBG("Deleting timer on metadata channel");
625 consumer_timer_switch_stop(channel);
626 }
627
628 if (channel->metadata_stream) {
629 ret = ustctl_stream_close_wakeup_fd(channel->metadata_stream->ustream);
630 if (ret < 0) {
631 ERR("UST consumer unable to close fd of metadata (ret: %d)", ret);
632 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
633 }
634
635 if (channel->monitor) {
636 /* Close the read-side in consumer_del_metadata_stream */
637 ret = close(channel->metadata_stream->ust_metadata_poll_pipe[1]);
638 if (ret < 0) {
639 PERROR("Close UST metadata write-side poll pipe");
640 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
641 }
642 }
643 }
644
645 return ret;
646 }
647
648 /*
649 * Close metadata stream wakeup_fd using the given key to retrieve the channel.
650 * RCU read side lock MUST be acquired before calling this function.
651 *
652 * Return 0 on success else an LTTng error code.
653 */
654 static int close_metadata(uint64_t chan_key)
655 {
656 int ret = 0;
657 struct lttng_consumer_channel *channel;
658
659 DBG("UST consumer close metadata key %" PRIu64, chan_key);
660
661 channel = consumer_find_channel(chan_key);
662 if (!channel) {
663 /*
664 * This is possible if the metadata thread has issue a delete because
665 * the endpoint point of the stream hung up. There is no way the
666 * session daemon can know about it thus use a DBG instead of an actual
667 * error.
668 */
669 DBG("UST consumer close metadata %" PRIu64 " not found", chan_key);
670 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
671 goto error;
672 }
673
674 pthread_mutex_lock(&consumer_data.lock);
675 pthread_mutex_lock(&channel->lock);
676
677 if (cds_lfht_is_node_deleted(&channel->node.node)) {
678 goto error_unlock;
679 }
680
681 ret = _close_metadata(channel);
682
683 error_unlock:
684 pthread_mutex_unlock(&channel->lock);
685 pthread_mutex_unlock(&consumer_data.lock);
686 error:
687 return ret;
688 }
689
690 /*
691 * RCU read side lock MUST be acquired before calling this function.
692 *
693 * Return 0 on success else an LTTng error code.
694 */
695 static int setup_metadata(struct lttng_consumer_local_data *ctx, uint64_t key)
696 {
697 int ret;
698 struct lttng_consumer_channel *metadata;
699
700 DBG("UST consumer setup metadata key %" PRIu64, key);
701
702 metadata = consumer_find_channel(key);
703 if (!metadata) {
704 ERR("UST consumer push metadata %" PRIu64 " not found", key);
705 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
706 goto end;
707 }
708
709 /*
710 * In no monitor mode, the metadata channel has no stream(s) so skip the
711 * ownership transfer to the metadata thread.
712 */
713 if (!metadata->monitor) {
714 DBG("Metadata channel in no monitor");
715 ret = 0;
716 goto end;
717 }
718
719 /*
720 * Send metadata stream to relayd if one available. Availability is
721 * known if the stream is still in the list of the channel.
722 */
723 if (cds_list_empty(&metadata->streams.head)) {
724 ERR("Metadata channel key %" PRIu64 ", no stream available.", key);
725 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
726 goto error_no_stream;
727 }
728
729 /* Send metadata stream to relayd if needed. */
730 if (metadata->metadata_stream->net_seq_idx != (uint64_t) -1ULL) {
731 ret = consumer_send_relayd_stream(metadata->metadata_stream,
732 metadata->pathname);
733 if (ret < 0) {
734 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
735 goto error;
736 }
737 }
738
739 ret = send_streams_to_thread(metadata, ctx);
740 if (ret < 0) {
741 /*
742 * If we are unable to send the stream to the thread, there is
743 * a big problem so just stop everything.
744 */
745 ret = LTTCOMM_CONSUMERD_FATAL;
746 goto error;
747 }
748 /* List MUST be empty after or else it could be reused. */
749 assert(cds_list_empty(&metadata->streams.head));
750
751 ret = 0;
752 goto end;
753
754 error:
755 /*
756 * Delete metadata channel on error. At this point, the metadata stream can
757 * NOT be monitored by the metadata thread thus having the guarantee that
758 * the stream is still in the local stream list of the channel. This call
759 * will make sure to clean that list.
760 */
761 cds_list_del(&metadata->metadata_stream->send_node);
762 consumer_stream_destroy(metadata->metadata_stream, NULL);
763 error_no_stream:
764 end:
765 return ret;
766 }
767
768 /*
769 * Snapshot the whole metadata.
770 *
771 * Returns 0 on success, < 0 on error
772 */
773 static int snapshot_metadata(uint64_t key, char *path, uint64_t relayd_id,
774 struct lttng_consumer_local_data *ctx)
775 {
776 int ret = 0;
777 struct lttng_consumer_channel *metadata_channel;
778 struct lttng_consumer_stream *metadata_stream;
779
780 assert(path);
781 assert(ctx);
782
783 DBG("UST consumer snapshot metadata with key %" PRIu64 " at path %s",
784 key, path);
785
786 rcu_read_lock();
787
788 metadata_channel = consumer_find_channel(key);
789 if (!metadata_channel) {
790 ERR("UST snapshot metadata channel not found for key %" PRIu64,
791 key);
792 ret = -1;
793 goto error;
794 }
795 assert(!metadata_channel->monitor);
796
797 /*
798 * Ask the sessiond if we have new metadata waiting and update the
799 * consumer metadata cache.
800 */
801 ret = lttng_ustconsumer_request_metadata(ctx, metadata_channel, 0);
802 if (ret < 0) {
803 goto error;
804 }
805
806 /*
807 * The metadata stream is NOT created in no monitor mode when the channel
808 * is created on a sessiond ask channel command.
809 */
810 ret = create_ust_streams(metadata_channel, ctx);
811 if (ret < 0) {
812 goto error;
813 }
814
815 metadata_stream = metadata_channel->metadata_stream;
816 assert(metadata_stream);
817
818 if (relayd_id != (uint64_t) -1ULL) {
819 metadata_stream->net_seq_idx = relayd_id;
820 ret = consumer_send_relayd_stream(metadata_stream, path);
821 if (ret < 0) {
822 goto error_stream;
823 }
824 } else {
825 ret = utils_create_stream_file(path, metadata_stream->name,
826 metadata_stream->chan->tracefile_size,
827 metadata_stream->tracefile_count_current,
828 metadata_stream->uid, metadata_stream->gid);
829 if (ret < 0) {
830 goto error_stream;
831 }
832 metadata_stream->out_fd = ret;
833 metadata_stream->tracefile_size_current = 0;
834 }
835
836 pthread_mutex_lock(&metadata_channel->metadata_cache->lock);
837
838 do {
839 ret = lttng_consumer_read_subbuffer(metadata_stream, ctx);
840 if (ret < 0) {
841 goto error_unlock;
842 }
843 } while (ret > 0);
844
845 error_unlock:
846 pthread_mutex_unlock(&metadata_channel->metadata_cache->lock);
847
848 error_stream:
849 /*
850 * Clean up the stream completly because the next snapshot will use a new
851 * metadata stream.
852 */
853 cds_list_del(&metadata_stream->send_node);
854 consumer_stream_destroy(metadata_stream, NULL);
855 metadata_channel->metadata_stream = NULL;
856
857 error:
858 rcu_read_unlock();
859 return ret;
860 }
861
862 /*
863 * Take a snapshot of all the stream of a channel.
864 *
865 * Returns 0 on success, < 0 on error
866 */
867 static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
868 uint64_t max_stream_size, struct lttng_consumer_local_data *ctx)
869 {
870 int ret;
871 unsigned use_relayd = 0;
872 unsigned long consumed_pos, produced_pos;
873 struct lttng_consumer_channel *channel;
874 struct lttng_consumer_stream *stream;
875
876 assert(path);
877 assert(ctx);
878
879 rcu_read_lock();
880
881 if (relayd_id != (uint64_t) -1ULL) {
882 use_relayd = 1;
883 }
884
885 channel = consumer_find_channel(key);
886 if (!channel) {
887 ERR("UST snapshot channel not found for key %" PRIu64, key);
888 ret = -1;
889 goto error;
890 }
891 assert(!channel->monitor);
892 DBG("UST consumer snapshot channel %" PRIu64, key);
893
894 cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
895 /* Lock stream because we are about to change its state. */
896 pthread_mutex_lock(&stream->lock);
897 stream->net_seq_idx = relayd_id;
898
899 if (use_relayd) {
900 ret = consumer_send_relayd_stream(stream, path);
901 if (ret < 0) {
902 goto error_unlock;
903 }
904 } else {
905 ret = utils_create_stream_file(path, stream->name,
906 stream->chan->tracefile_size,
907 stream->tracefile_count_current,
908 stream->uid, stream->gid);
909 if (ret < 0) {
910 goto error_unlock;
911 }
912 stream->out_fd = ret;
913 stream->tracefile_size_current = 0;
914
915 DBG("UST consumer snapshot stream %s/%s (%" PRIu64 ")", path,
916 stream->name, stream->key);
917 }
918
919 ustctl_flush_buffer(stream->ustream, 1);
920
921 ret = lttng_ustconsumer_take_snapshot(stream);
922 if (ret < 0) {
923 ERR("Taking UST snapshot");
924 goto error_unlock;
925 }
926
927 ret = lttng_ustconsumer_get_produced_snapshot(stream, &produced_pos);
928 if (ret < 0) {
929 ERR("Produced UST snapshot position");
930 goto error_unlock;
931 }
932
933 ret = lttng_ustconsumer_get_consumed_snapshot(stream, &consumed_pos);
934 if (ret < 0) {
935 ERR("Consumerd UST snapshot position");
936 goto error_unlock;
937 }
938
939 /*
940 * The original value is sent back if max stream size is larger than
941 * the possible size of the snapshot. Also, we asume that the session
942 * daemon should never send a maximum stream size that is lower than
943 * subbuffer size.
944 */
945 consumed_pos = consumer_get_consumed_maxsize(consumed_pos,
946 produced_pos, max_stream_size);
947
948 while (consumed_pos < produced_pos) {
949 ssize_t read_len;
950 unsigned long len, padded_len;
951
952 DBG("UST consumer taking snapshot at pos %lu", consumed_pos);
953
954 ret = ustctl_get_subbuf(stream->ustream, &consumed_pos);
955 if (ret < 0) {
956 if (ret != -EAGAIN) {
957 PERROR("ustctl_get_subbuf snapshot");
958 goto error_close_stream;
959 }
960 DBG("UST consumer get subbuf failed. Skipping it.");
961 consumed_pos += stream->max_sb_size;
962 continue;
963 }
964
965 ret = ustctl_get_subbuf_size(stream->ustream, &len);
966 if (ret < 0) {
967 ERR("Snapshot ustctl_get_subbuf_size");
968 goto error_put_subbuf;
969 }
970
971 ret = ustctl_get_padded_subbuf_size(stream->ustream, &padded_len);
972 if (ret < 0) {
973 ERR("Snapshot ustctl_get_padded_subbuf_size");
974 goto error_put_subbuf;
975 }
976
977 read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
978 padded_len - len);
979 if (use_relayd) {
980 if (read_len != len) {
981 ret = -EPERM;
982 goto error_put_subbuf;
983 }
984 } else {
985 if (read_len != padded_len) {
986 ret = -EPERM;
987 goto error_put_subbuf;
988 }
989 }
990
991 ret = ustctl_put_subbuf(stream->ustream);
992 if (ret < 0) {
993 ERR("Snapshot ustctl_put_subbuf");
994 goto error_close_stream;
995 }
996 consumed_pos += stream->max_sb_size;
997 }
998
999 /* Simply close the stream so we can use it on the next snapshot. */
1000 consumer_stream_close(stream);
1001 pthread_mutex_unlock(&stream->lock);
1002 }
1003
1004 rcu_read_unlock();
1005 return 0;
1006
1007 error_put_subbuf:
1008 if (ustctl_put_subbuf(stream->ustream) < 0) {
1009 ERR("Snapshot ustctl_put_subbuf");
1010 }
1011 error_close_stream:
1012 consumer_stream_close(stream);
1013 error_unlock:
1014 pthread_mutex_unlock(&stream->lock);
1015 error:
1016 rcu_read_unlock();
1017 return ret;
1018 }
1019
1020 /*
1021 * Receive the metadata updates from the sessiond.
1022 */
1023 int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
1024 uint64_t len, struct lttng_consumer_channel *channel,
1025 int timer)
1026 {
1027 int ret, ret_code = LTTNG_OK;
1028 char *metadata_str;
1029
1030 DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key, len);
1031
1032 metadata_str = zmalloc(len * sizeof(char));
1033 if (!metadata_str) {
1034 PERROR("zmalloc metadata string");
1035 ret_code = LTTCOMM_CONSUMERD_ENOMEM;
1036 goto end;
1037 }
1038
1039 /* Receive metadata string. */
1040 ret = lttcomm_recv_unix_sock(sock, metadata_str, len);
1041 if (ret < 0) {
1042 /* Session daemon is dead so return gracefully. */
1043 ret_code = ret;
1044 goto end_free;
1045 }
1046
1047 pthread_mutex_lock(&channel->metadata_cache->lock);
1048 ret = consumer_metadata_cache_write(channel, offset, len, metadata_str);
1049 if (ret < 0) {
1050 /* Unable to handle metadata. Notify session daemon. */
1051 ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
1052 /*
1053 * Skip metadata flush on write error since the offset and len might
1054 * not have been updated which could create an infinite loop below when
1055 * waiting for the metadata cache to be flushed.
1056 */
1057 pthread_mutex_unlock(&channel->metadata_cache->lock);
1058 goto end_free;
1059 }
1060 pthread_mutex_unlock(&channel->metadata_cache->lock);
1061
1062 while (consumer_metadata_cache_flushed(channel, offset + len, timer)) {
1063 DBG("Waiting for metadata to be flushed");
1064 usleep(DEFAULT_METADATA_AVAILABILITY_WAIT_TIME);
1065 }
1066
1067 end_free:
1068 free(metadata_str);
1069 end:
1070 return ret_code;
1071 }
1072
1073 /*
1074 * Receive command from session daemon and process it.
1075 *
1076 * Return 1 on success else a negative value or 0.
1077 */
1078 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
1079 int sock, struct pollfd *consumer_sockpoll)
1080 {
1081 ssize_t ret;
1082 enum lttng_error_code ret_code = LTTNG_OK;
1083 struct lttcomm_consumer_msg msg;
1084 struct lttng_consumer_channel *channel = NULL;
1085
1086 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
1087 if (ret != sizeof(msg)) {
1088 DBG("Consumer received unexpected message size %zd (expects %zu)",
1089 ret, sizeof(msg));
1090 /*
1091 * The ret value might 0 meaning an orderly shutdown but this is ok
1092 * since the caller handles this.
1093 */
1094 if (ret > 0) {
1095 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
1096 ret = -1;
1097 }
1098 return ret;
1099 }
1100 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
1101 /*
1102 * Notify the session daemon that the command is completed.
1103 *
1104 * On transport layer error, the function call will print an error
1105 * message so handling the returned code is a bit useless since we
1106 * return an error code anyway.
1107 */
1108 (void) consumer_send_status_msg(sock, ret_code);
1109 return -ENOENT;
1110 }
1111
1112 /* relayd needs RCU read-side lock */
1113 rcu_read_lock();
1114
1115 switch (msg.cmd_type) {
1116 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
1117 {
1118 /* Session daemon status message are handled in the following call. */
1119 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
1120 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
1121 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id);
1122 goto end_nosignal;
1123 }
1124 case LTTNG_CONSUMER_DESTROY_RELAYD:
1125 {
1126 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
1127 struct consumer_relayd_sock_pair *relayd;
1128
1129 DBG("UST consumer destroying relayd %" PRIu64, index);
1130
1131 /* Get relayd reference if exists. */
1132 relayd = consumer_find_relayd(index);
1133 if (relayd == NULL) {
1134 DBG("Unable to find relayd %" PRIu64, index);
1135 ret_code = LTTNG_ERR_NO_CONSUMER;
1136 }
1137
1138 /*
1139 * Each relayd socket pair has a refcount of stream attached to it
1140 * which tells if the relayd is still active or not depending on the
1141 * refcount value.
1142 *
1143 * This will set the destroy flag of the relayd object and destroy it
1144 * if the refcount reaches zero when called.
1145 *
1146 * The destroy can happen either here or when a stream fd hangs up.
1147 */
1148 if (relayd) {
1149 consumer_flag_relayd_for_destroy(relayd);
1150 }
1151
1152 goto end_msg_sessiond;
1153 }
1154 case LTTNG_CONSUMER_UPDATE_STREAM:
1155 {
1156 rcu_read_unlock();
1157 return -ENOSYS;
1158 }
1159 case LTTNG_CONSUMER_DATA_PENDING:
1160 {
1161 int ret, is_data_pending;
1162 uint64_t id = msg.u.data_pending.session_id;
1163
1164 DBG("UST consumer data pending command for id %" PRIu64, id);
1165
1166 is_data_pending = consumer_data_pending(id);
1167
1168 /* Send back returned value to session daemon */
1169 ret = lttcomm_send_unix_sock(sock, &is_data_pending,
1170 sizeof(is_data_pending));
1171 if (ret < 0) {
1172 DBG("Error when sending the data pending ret code: %d", ret);
1173 goto error_fatal;
1174 }
1175
1176 /*
1177 * No need to send back a status message since the data pending
1178 * returned value is the response.
1179 */
1180 break;
1181 }
1182 case LTTNG_CONSUMER_ASK_CHANNEL_CREATION:
1183 {
1184 int ret;
1185 struct ustctl_consumer_channel_attr attr;
1186
1187 /* Create a plain object and reserve a channel key. */
1188 channel = allocate_channel(msg.u.ask_channel.session_id,
1189 msg.u.ask_channel.pathname, msg.u.ask_channel.name,
1190 msg.u.ask_channel.uid, msg.u.ask_channel.gid,
1191 msg.u.ask_channel.relayd_id, msg.u.ask_channel.key,
1192 (enum lttng_event_output) msg.u.ask_channel.output,
1193 msg.u.ask_channel.tracefile_size,
1194 msg.u.ask_channel.tracefile_count,
1195 msg.u.ask_channel.session_id_per_pid,
1196 msg.u.ask_channel.monitor);
1197 if (!channel) {
1198 goto end_channel_error;
1199 }
1200
1201 /*
1202 * Assign UST application UID to the channel. This value is ignored for
1203 * per PID buffers. This is specific to UST thus setting this after the
1204 * allocation.
1205 */
1206 channel->ust_app_uid = msg.u.ask_channel.ust_app_uid;
1207
1208 /* Build channel attributes from received message. */
1209 attr.subbuf_size = msg.u.ask_channel.subbuf_size;
1210 attr.num_subbuf = msg.u.ask_channel.num_subbuf;
1211 attr.overwrite = msg.u.ask_channel.overwrite;
1212 attr.switch_timer_interval = msg.u.ask_channel.switch_timer_interval;
1213 attr.read_timer_interval = msg.u.ask_channel.read_timer_interval;
1214 attr.chan_id = msg.u.ask_channel.chan_id;
1215 attr.output = msg.u.ask_channel.output;
1216 memcpy(attr.uuid, msg.u.ask_channel.uuid, sizeof(attr.uuid));
1217
1218 /* Translate and save channel type. */
1219 switch (msg.u.ask_channel.type) {
1220 case LTTNG_UST_CHAN_PER_CPU:
1221 channel->type = CONSUMER_CHANNEL_TYPE_DATA;
1222 attr.type = LTTNG_UST_CHAN_PER_CPU;
1223 /*
1224 * Set refcount to 1 for owner. Below, we will
1225 * pass ownership to the
1226 * consumer_thread_channel_poll() thread.
1227 */
1228 channel->refcount = 1;
1229 break;
1230 case LTTNG_UST_CHAN_METADATA:
1231 channel->type = CONSUMER_CHANNEL_TYPE_METADATA;
1232 attr.type = LTTNG_UST_CHAN_METADATA;
1233 break;
1234 default:
1235 assert(0);
1236 goto error_fatal;
1237 };
1238
1239 ret = ask_channel(ctx, sock, channel, &attr);
1240 if (ret < 0) {
1241 goto end_channel_error;
1242 }
1243
1244 if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
1245 ret = consumer_metadata_cache_allocate(channel);
1246 if (ret < 0) {
1247 ERR("Allocating metadata cache");
1248 goto end_channel_error;
1249 }
1250 consumer_timer_switch_start(channel, attr.switch_timer_interval);
1251 attr.switch_timer_interval = 0;
1252 }
1253
1254 /*
1255 * Add the channel to the internal state AFTER all streams were created
1256 * and successfully sent to session daemon. This way, all streams must
1257 * be ready before this channel is visible to the threads.
1258 * If add_channel succeeds, ownership of the channel is
1259 * passed to consumer_thread_channel_poll().
1260 */
1261 ret = add_channel(channel, ctx);
1262 if (ret < 0) {
1263 if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
1264 if (channel->switch_timer_enabled == 1) {
1265 consumer_timer_switch_stop(channel);
1266 }
1267 consumer_metadata_cache_destroy(channel);
1268 }
1269 goto end_channel_error;
1270 }
1271
1272 /*
1273 * Channel and streams are now created. Inform the session daemon that
1274 * everything went well and should wait to receive the channel and
1275 * streams with ustctl API.
1276 */
1277 ret = consumer_send_status_channel(sock, channel);
1278 if (ret < 0) {
1279 /*
1280 * There is probably a problem on the socket.
1281 */
1282 goto error_fatal;
1283 }
1284
1285 break;
1286 }
1287 case LTTNG_CONSUMER_GET_CHANNEL:
1288 {
1289 int ret, relayd_err = 0;
1290 uint64_t key = msg.u.get_channel.key;
1291 struct lttng_consumer_channel *channel;
1292
1293 channel = consumer_find_channel(key);
1294 if (!channel) {
1295 ERR("UST consumer get channel key %" PRIu64 " not found", key);
1296 ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1297 goto end_msg_sessiond;
1298 }
1299
1300 /* Send everything to sessiond. */
1301 ret = send_sessiond_channel(sock, channel, ctx, &relayd_err);
1302 if (ret < 0) {
1303 if (relayd_err) {
1304 /*
1305 * We were unable to send to the relayd the stream so avoid
1306 * sending back a fatal error to the thread since this is OK
1307 * and the consumer can continue its work. The above call
1308 * has sent the error status message to the sessiond.
1309 */
1310 goto end_nosignal;
1311 }
1312 /*
1313 * The communicaton was broken hence there is a bad state between
1314 * the consumer and sessiond so stop everything.
1315 */
1316 goto error_fatal;
1317 }
1318
1319 /*
1320 * In no monitor mode, the streams ownership is kept inside the channel
1321 * so don't send them to the data thread.
1322 */
1323 if (!channel->monitor) {
1324 goto end_msg_sessiond;
1325 }
1326
1327 ret = send_streams_to_thread(channel, ctx);
1328 if (ret < 0) {
1329 /*
1330 * If we are unable to send the stream to the thread, there is
1331 * a big problem so just stop everything.
1332 */
1333 goto error_fatal;
1334 }
1335 /* List MUST be empty after or else it could be reused. */
1336 assert(cds_list_empty(&channel->streams.head));
1337 goto end_msg_sessiond;
1338 }
1339 case LTTNG_CONSUMER_DESTROY_CHANNEL:
1340 {
1341 uint64_t key = msg.u.destroy_channel.key;
1342
1343 /*
1344 * Only called if streams have not been sent to stream
1345 * manager thread. However, channel has been sent to
1346 * channel manager thread.
1347 */
1348 notify_thread_del_channel(ctx, key);
1349 goto end_msg_sessiond;
1350 }
1351 case LTTNG_CONSUMER_CLOSE_METADATA:
1352 {
1353 int ret;
1354
1355 ret = close_metadata(msg.u.close_metadata.key);
1356 if (ret != 0) {
1357 ret_code = ret;
1358 }
1359
1360 goto end_msg_sessiond;
1361 }
1362 case LTTNG_CONSUMER_FLUSH_CHANNEL:
1363 {
1364 int ret;
1365
1366 ret = flush_channel(msg.u.flush_channel.key);
1367 if (ret != 0) {
1368 ret_code = ret;
1369 }
1370
1371 goto end_msg_sessiond;
1372 }
1373 case LTTNG_CONSUMER_PUSH_METADATA:
1374 {
1375 int ret;
1376 uint64_t len = msg.u.push_metadata.len;
1377 uint64_t key = msg.u.push_metadata.key;
1378 uint64_t offset = msg.u.push_metadata.target_offset;
1379 struct lttng_consumer_channel *channel;
1380
1381 DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key,
1382 len);
1383
1384 channel = consumer_find_channel(key);
1385 if (!channel) {
1386 ERR("UST consumer push metadata %" PRIu64 " not found", key);
1387 ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1388 goto end_msg_sessiond;
1389 }
1390
1391 /* Tell session daemon we are ready to receive the metadata. */
1392 ret = consumer_send_status_msg(sock, LTTNG_OK);
1393 if (ret < 0) {
1394 /* Somehow, the session daemon is not responding anymore. */
1395 goto error_fatal;
1396 }
1397
1398 /* Wait for more data. */
1399 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
1400 goto error_fatal;
1401 }
1402
1403 ret = lttng_ustconsumer_recv_metadata(sock, key, offset,
1404 len, channel, 0);
1405 if (ret < 0) {
1406 /* error receiving from sessiond */
1407 goto error_fatal;
1408 } else {
1409 ret_code = ret;
1410 goto end_msg_sessiond;
1411 }
1412 }
1413 case LTTNG_CONSUMER_SETUP_METADATA:
1414 {
1415 int ret;
1416
1417 ret = setup_metadata(ctx, msg.u.setup_metadata.key);
1418 if (ret) {
1419 ret_code = ret;
1420 }
1421 goto end_msg_sessiond;
1422 }
1423 case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
1424 {
1425 if (msg.u.snapshot_channel.metadata) {
1426 ret = snapshot_metadata(msg.u.snapshot_channel.key,
1427 msg.u.snapshot_channel.pathname,
1428 msg.u.snapshot_channel.relayd_id,
1429 ctx);
1430 if (ret < 0) {
1431 ERR("Snapshot metadata failed");
1432 ret_code = LTTNG_ERR_UST_META_FAIL;
1433 }
1434 } else {
1435 ret = snapshot_channel(msg.u.snapshot_channel.key,
1436 msg.u.snapshot_channel.pathname,
1437 msg.u.snapshot_channel.relayd_id,
1438 msg.u.snapshot_channel.max_stream_size,
1439 ctx);
1440 if (ret < 0) {
1441 ERR("Snapshot channel failed");
1442 ret_code = LTTNG_ERR_UST_CHAN_FAIL;
1443 }
1444 }
1445
1446 ret = consumer_send_status_msg(sock, ret_code);
1447 if (ret < 0) {
1448 /* Somehow, the session daemon is not responding anymore. */
1449 goto end_nosignal;
1450 }
1451 break;
1452 }
1453 default:
1454 break;
1455 }
1456
1457 end_nosignal:
1458 rcu_read_unlock();
1459
1460 /*
1461 * Return 1 to indicate success since the 0 value can be a socket
1462 * shutdown during the recv() or send() call.
1463 */
1464 return 1;
1465
1466 end_msg_sessiond:
1467 /*
1468 * The returned value here is not useful since either way we'll return 1 to
1469 * the caller because the session daemon socket management is done
1470 * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1471 */
1472 ret = consumer_send_status_msg(sock, ret_code);
1473 if (ret < 0) {
1474 goto error_fatal;
1475 }
1476 rcu_read_unlock();
1477 return 1;
1478 end_channel_error:
1479 if (channel) {
1480 /*
1481 * Free channel here since no one has a reference to it. We don't
1482 * free after that because a stream can store this pointer.
1483 */
1484 destroy_channel(channel);
1485 }
1486 /* We have to send a status channel message indicating an error. */
1487 ret = consumer_send_status_channel(sock, NULL);
1488 if (ret < 0) {
1489 /* Stop everything if session daemon can not be notified. */
1490 goto error_fatal;
1491 }
1492 rcu_read_unlock();
1493 return 1;
1494 error_fatal:
1495 rcu_read_unlock();
1496 /* This will issue a consumer stop. */
1497 return -1;
1498 }
1499
1500 /*
1501 * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
1502 * compiled out, we isolate it in this library.
1503 */
1504 int lttng_ustctl_get_mmap_read_offset(struct lttng_consumer_stream *stream,
1505 unsigned long *off)
1506 {
1507 assert(stream);
1508 assert(stream->ustream);
1509
1510 return ustctl_get_mmap_read_offset(stream->ustream, off);
1511 }
1512
1513 /*
1514 * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
1515 * compiled out, we isolate it in this library.
1516 */
1517 void *lttng_ustctl_get_mmap_base(struct lttng_consumer_stream *stream)
1518 {
1519 assert(stream);
1520 assert(stream->ustream);
1521
1522 return ustctl_get_mmap_base(stream->ustream);
1523 }
1524
1525 /*
1526 * Take a snapshot for a specific fd
1527 *
1528 * Returns 0 on success, < 0 on error
1529 */
1530 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_stream *stream)
1531 {
1532 assert(stream);
1533 assert(stream->ustream);
1534
1535 return ustctl_snapshot(stream->ustream);
1536 }
1537
1538 /*
1539 * Get the produced position
1540 *
1541 * Returns 0 on success, < 0 on error
1542 */
1543 int lttng_ustconsumer_get_produced_snapshot(
1544 struct lttng_consumer_stream *stream, unsigned long *pos)
1545 {
1546 assert(stream);
1547 assert(stream->ustream);
1548 assert(pos);
1549
1550 return ustctl_snapshot_get_produced(stream->ustream, pos);
1551 }
1552
1553 /*
1554 * Get the consumed position
1555 *
1556 * Returns 0 on success, < 0 on error
1557 */
1558 int lttng_ustconsumer_get_consumed_snapshot(
1559 struct lttng_consumer_stream *stream, unsigned long *pos)
1560 {
1561 assert(stream);
1562 assert(stream->ustream);
1563 assert(pos);
1564
1565 return ustctl_snapshot_get_consumed(stream->ustream, pos);
1566 }
1567
1568 /*
1569 * Called when the stream signal the consumer that it has hang up.
1570 */
1571 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
1572 {
1573 assert(stream);
1574 assert(stream->ustream);
1575
1576 ustctl_flush_buffer(stream->ustream, 0);
1577 stream->hangup_flush_done = 1;
1578 }
1579
1580 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
1581 {
1582 assert(chan);
1583 assert(chan->uchan);
1584
1585 if (chan->switch_timer_enabled == 1) {
1586 consumer_timer_switch_stop(chan);
1587 }
1588 consumer_metadata_cache_destroy(chan);
1589 ustctl_destroy_channel(chan->uchan);
1590 }
1591
1592 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
1593 {
1594 assert(stream);
1595 assert(stream->ustream);
1596
1597 if (stream->chan->switch_timer_enabled == 1) {
1598 consumer_timer_switch_stop(stream->chan);
1599 }
1600 ustctl_destroy_stream(stream->ustream);
1601 }
1602
1603 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
1604 struct lttng_consumer_local_data *ctx)
1605 {
1606 unsigned long len, subbuf_size, padding;
1607 int err;
1608 long ret = 0;
1609 char dummy;
1610 struct ustctl_consumer_stream *ustream;
1611
1612 assert(stream);
1613 assert(stream->ustream);
1614 assert(ctx);
1615
1616 DBG("In UST read_subbuffer (wait_fd: %d, name: %s)", stream->wait_fd,
1617 stream->name);
1618
1619 /* Ease our life for what's next. */
1620 ustream = stream->ustream;
1621
1622 /* We can consume the 1 byte written into the wait_fd by UST */
1623 if (stream->monitor && !stream->hangup_flush_done) {
1624 ssize_t readlen;
1625
1626 do {
1627 readlen = read(stream->wait_fd, &dummy, 1);
1628 } while (readlen == -1 && errno == EINTR);
1629 if (readlen == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
1630 ret = readlen;
1631 goto end;
1632 }
1633 }
1634
1635 retry:
1636 /* Get the next subbuffer */
1637 err = ustctl_get_next_subbuf(ustream);
1638 if (err != 0) {
1639 /*
1640 * Populate metadata info if the existing info has
1641 * already been read.
1642 */
1643 if (stream->metadata_flag) {
1644 ssize_t write_len;
1645
1646 if (stream->chan->metadata_cache->contiguous
1647 == stream->ust_metadata_pushed) {
1648 ret = 0;
1649 goto end;
1650 }
1651
1652 write_len = ustctl_write_one_packet_to_channel(stream->chan->uchan,
1653 &stream->chan->metadata_cache->data[stream->ust_metadata_pushed],
1654 stream->chan->metadata_cache->contiguous
1655 - stream->ust_metadata_pushed);
1656 assert(write_len != 0);
1657 if (write_len < 0) {
1658 ERR("Writing one metadata packet");
1659 ret = -1;
1660 goto end;
1661 }
1662 stream->ust_metadata_pushed += write_len;
1663 ustctl_flush_buffer(stream->ustream, 1);
1664 goto retry;
1665 }
1666
1667 ret = err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
1668 /*
1669 * This is a debug message even for single-threaded consumer,
1670 * because poll() have more relaxed criterions than get subbuf,
1671 * so get_subbuf may fail for short race windows where poll()
1672 * would issue wakeups.
1673 */
1674 DBG("Reserving sub buffer failed (everything is normal, "
1675 "it is due to concurrency) [ret: %d]", err);
1676 goto end;
1677 }
1678 assert(stream->chan->output == CONSUMER_CHANNEL_MMAP);
1679 /* Get the full padded subbuffer size */
1680 err = ustctl_get_padded_subbuf_size(ustream, &len);
1681 assert(err == 0);
1682
1683 /* Get subbuffer data size (without padding) */
1684 err = ustctl_get_subbuf_size(ustream, &subbuf_size);
1685 assert(err == 0);
1686
1687 /* Make sure we don't get a subbuffer size bigger than the padded */
1688 assert(len >= subbuf_size);
1689
1690 padding = len - subbuf_size;
1691 /* write the subbuffer to the tracefile */
1692 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
1693 /*
1694 * The mmap operation should write subbuf_size amount of data when network
1695 * streaming or the full padding (len) size when we are _not_ streaming.
1696 */
1697 if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
1698 (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
1699 /*
1700 * Display the error but continue processing to try to release the
1701 * subbuffer. This is a DBG statement since any unexpected kill or
1702 * signal, the application gets unregistered, relayd gets closed or
1703 * anything that affects the buffer lifetime will trigger this error.
1704 * So, for the sake of the user, don't print this error since it can
1705 * happen and it is OK with the code flow.
1706 */
1707 DBG("Error writing to tracefile "
1708 "(ret: %ld != len: %lu != subbuf_size: %lu)",
1709 ret, len, subbuf_size);
1710 }
1711 err = ustctl_put_next_subbuf(ustream);
1712 assert(err == 0);
1713
1714 end:
1715 return ret;
1716 }
1717
1718 /*
1719 * Called when a stream is created.
1720 *
1721 * Return 0 on success or else a negative value.
1722 */
1723 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1724 {
1725 int ret;
1726
1727 assert(stream);
1728
1729 /* Don't create anything if this is set for streaming. */
1730 if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor) {
1731 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
1732 stream->chan->tracefile_size, stream->tracefile_count_current,
1733 stream->uid, stream->gid);
1734 if (ret < 0) {
1735 goto error;
1736 }
1737 stream->out_fd = ret;
1738 stream->tracefile_size_current = 0;
1739 }
1740 ret = 0;
1741
1742 error:
1743 return ret;
1744 }
1745
1746 /*
1747 * Check if data is still being extracted from the buffers for a specific
1748 * stream. Consumer data lock MUST be acquired before calling this function
1749 * and the stream lock.
1750 *
1751 * Return 1 if the traced data are still getting read else 0 meaning that the
1752 * data is available for trace viewer reading.
1753 */
1754 int lttng_ustconsumer_data_pending(struct lttng_consumer_stream *stream)
1755 {
1756 int ret;
1757
1758 assert(stream);
1759 assert(stream->ustream);
1760
1761 DBG("UST consumer checking data pending");
1762
1763 if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1764 ret = 0;
1765 goto end;
1766 }
1767
1768 if (stream->chan->type == CONSUMER_CHANNEL_TYPE_METADATA) {
1769 uint64_t contiguous, pushed;
1770
1771 /* Ease our life a bit. */
1772 contiguous = stream->chan->metadata_cache->contiguous;
1773 pushed = stream->ust_metadata_pushed;
1774
1775 /*
1776 * We can simply check whether all contiguously available data
1777 * has been pushed to the ring buffer, since the push operation
1778 * is performed within get_next_subbuf(), and because both
1779 * get_next_subbuf() and put_next_subbuf() are issued atomically
1780 * thanks to the stream lock within
1781 * lttng_ustconsumer_read_subbuffer(). This basically means that
1782 * whetnever ust_metadata_pushed is incremented, the associated
1783 * metadata has been consumed from the metadata stream.
1784 */
1785 DBG("UST consumer metadata pending check: contiguous %" PRIu64 " vs pushed %" PRIu64,
1786 contiguous, pushed);
1787 assert(((int64_t) contiguous - pushed) >= 0);
1788 if ((contiguous != pushed) ||
1789 (((int64_t) contiguous - pushed) > 0 || contiguous == 0)) {
1790 ret = 1; /* Data is pending */
1791 goto end;
1792 }
1793 } else {
1794 ret = ustctl_get_next_subbuf(stream->ustream);
1795 if (ret == 0) {
1796 /*
1797 * There is still data so let's put back this
1798 * subbuffer.
1799 */
1800 ret = ustctl_put_subbuf(stream->ustream);
1801 assert(ret == 0);
1802 ret = 1; /* Data is pending */
1803 goto end;
1804 }
1805 }
1806
1807 /* Data is NOT pending so ready to be read. */
1808 ret = 0;
1809
1810 end:
1811 return ret;
1812 }
1813
1814 /*
1815 * Close every metadata stream wait fd of the metadata hash table. This
1816 * function MUST be used very carefully so not to run into a race between the
1817 * metadata thread handling streams and this function closing their wait fd.
1818 *
1819 * For UST, this is used when the session daemon hangs up. Its the metadata
1820 * producer so calling this is safe because we are assured that no state change
1821 * can occur in the metadata thread for the streams in the hash table.
1822 */
1823 void lttng_ustconsumer_close_metadata(struct lttng_ht *metadata_ht)
1824 {
1825 struct lttng_ht_iter iter;
1826 struct lttng_consumer_stream *stream;
1827
1828 assert(metadata_ht);
1829 assert(metadata_ht->ht);
1830
1831 DBG("UST consumer closing all metadata streams");
1832
1833 rcu_read_lock();
1834 cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream,
1835 node.node) {
1836 pthread_mutex_lock(&stream->chan->lock);
1837 /*
1838 * Whatever returned value, we must continue to try to close everything
1839 * so ignore it.
1840 */
1841 (void) _close_metadata(stream->chan);
1842 DBG("Metadata wait fd %d and poll pipe fd %d closed", stream->wait_fd,
1843 stream->ust_metadata_poll_pipe[1]);
1844 pthread_mutex_unlock(&stream->chan->lock);
1845
1846 }
1847 rcu_read_unlock();
1848 }
1849
1850 void lttng_ustconsumer_close_stream_wakeup(struct lttng_consumer_stream *stream)
1851 {
1852 int ret;
1853
1854 ret = ustctl_stream_close_wakeup_fd(stream->ustream);
1855 if (ret < 0) {
1856 ERR("Unable to close wakeup fd");
1857 }
1858 }
1859
1860 /*
1861 * Please refer to consumer-timer.c before adding any lock within this
1862 * function or any of its callees. Timers have a very strict locking
1863 * semantic with respect to teardown. Failure to respect this semantic
1864 * introduces deadlocks.
1865 */
1866 int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
1867 struct lttng_consumer_channel *channel, int timer)
1868 {
1869 struct lttcomm_metadata_request_msg request;
1870 struct lttcomm_consumer_msg msg;
1871 enum lttng_error_code ret_code = LTTNG_OK;
1872 uint64_t len, key, offset;
1873 int ret;
1874
1875 assert(channel);
1876 assert(channel->metadata_cache);
1877
1878 /* send the metadata request to sessiond */
1879 switch (consumer_data.type) {
1880 case LTTNG_CONSUMER64_UST:
1881 request.bits_per_long = 64;
1882 break;
1883 case LTTNG_CONSUMER32_UST:
1884 request.bits_per_long = 32;
1885 break;
1886 default:
1887 request.bits_per_long = 0;
1888 break;
1889 }
1890
1891 request.session_id = channel->session_id;
1892 request.session_id_per_pid = channel->session_id_per_pid;
1893 /*
1894 * Request the application UID here so the metadata of that application can
1895 * be sent back. The channel UID corresponds to the user UID of the session
1896 * used for the rights on the stream file(s).
1897 */
1898 request.uid = channel->ust_app_uid;
1899 request.key = channel->key;
1900
1901 DBG("Sending metadata request to sessiond, session id %" PRIu64
1902 ", per-pid %" PRIu64 ", app UID %u and channek key %" PRIu64,
1903 request.session_id, request.session_id_per_pid, request.uid,
1904 request.key);
1905
1906 pthread_mutex_lock(&ctx->metadata_socket_lock);
1907 ret = lttcomm_send_unix_sock(ctx->consumer_metadata_socket, &request,
1908 sizeof(request));
1909 if (ret < 0) {
1910 ERR("Asking metadata to sessiond");
1911 goto end;
1912 }
1913
1914 /* Receive the metadata from sessiond */
1915 ret = lttcomm_recv_unix_sock(ctx->consumer_metadata_socket, &msg,
1916 sizeof(msg));
1917 if (ret != sizeof(msg)) {
1918 DBG("Consumer received unexpected message size %d (expects %zu)",
1919 ret, sizeof(msg));
1920 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
1921 /*
1922 * The ret value might 0 meaning an orderly shutdown but this is ok
1923 * since the caller handles this.
1924 */
1925 goto end;
1926 }
1927
1928 if (msg.cmd_type == LTTNG_ERR_UND) {
1929 /* No registry found */
1930 (void) consumer_send_status_msg(ctx->consumer_metadata_socket,
1931 ret_code);
1932 ret = 0;
1933 goto end;
1934 } else if (msg.cmd_type != LTTNG_CONSUMER_PUSH_METADATA) {
1935 ERR("Unexpected cmd_type received %d", msg.cmd_type);
1936 ret = -1;
1937 goto end;
1938 }
1939
1940 len = msg.u.push_metadata.len;
1941 key = msg.u.push_metadata.key;
1942 offset = msg.u.push_metadata.target_offset;
1943
1944 assert(key == channel->key);
1945 if (len == 0) {
1946 DBG("No new metadata to receive for key %" PRIu64, key);
1947 }
1948
1949 /* Tell session daemon we are ready to receive the metadata. */
1950 ret = consumer_send_status_msg(ctx->consumer_metadata_socket,
1951 LTTNG_OK);
1952 if (ret < 0 || len == 0) {
1953 /*
1954 * Somehow, the session daemon is not responding anymore or there is
1955 * nothing to receive.
1956 */
1957 goto end;
1958 }
1959
1960 ret_code = lttng_ustconsumer_recv_metadata(ctx->consumer_metadata_socket,
1961 key, offset, len, channel, timer);
1962 if (ret_code >= 0) {
1963 /*
1964 * Only send the status msg if the sessiond is alive meaning a positive
1965 * ret code.
1966 */
1967 (void) consumer_send_status_msg(ctx->consumer_metadata_socket, ret_code);
1968 }
1969 ret = 0;
1970
1971 end:
1972 pthread_mutex_unlock(&ctx->metadata_socket_lock);
1973 return ret;
1974 }
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