Fix: sessiond: metadata not created on app unregistration during start
[lttng-tools.git] / src / bin / lttng-sessiond / ust-app.c
1 /*
2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
3 * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 *
5 * SPDX-License-Identifier: GPL-2.0-only
6 *
7 */
8
9 #define _LGPL_SOURCE
10 #include <inttypes.h>
11 #include <pthread.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <sys/stat.h>
16 #include <sys/types.h>
17 #include <unistd.h>
18 #include <urcu/compiler.h>
19 #include <signal.h>
20
21 #include <common/compat/errno.h>
22 #include <common/common.h>
23 #include <common/sessiond-comm/sessiond-comm.h>
24
25 #include "buffer-registry.h"
26 #include "fd-limit.h"
27 #include "health-sessiond.h"
28 #include "ust-app.h"
29 #include "ust-consumer.h"
30 #include "lttng-ust-ctl.h"
31 #include "lttng-ust-error.h"
32 #include "utils.h"
33 #include "session.h"
34 #include "lttng-sessiond.h"
35 #include "notification-thread-commands.h"
36 #include "rotate.h"
37
38 struct lttng_ht *ust_app_ht;
39 struct lttng_ht *ust_app_ht_by_sock;
40 struct lttng_ht *ust_app_ht_by_notify_sock;
41
42 static
43 int ust_app_flush_app_session(struct ust_app *app, struct ust_app_session *ua_sess);
44
45 /* Next available channel key. Access under next_channel_key_lock. */
46 static uint64_t _next_channel_key;
47 static pthread_mutex_t next_channel_key_lock = PTHREAD_MUTEX_INITIALIZER;
48
49 /* Next available session ID. Access under next_session_id_lock. */
50 static uint64_t _next_session_id;
51 static pthread_mutex_t next_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
52
53 /*
54 * Return the incremented value of next_channel_key.
55 */
56 static uint64_t get_next_channel_key(void)
57 {
58 uint64_t ret;
59
60 pthread_mutex_lock(&next_channel_key_lock);
61 ret = ++_next_channel_key;
62 pthread_mutex_unlock(&next_channel_key_lock);
63 return ret;
64 }
65
66 /*
67 * Return the atomically incremented value of next_session_id.
68 */
69 static uint64_t get_next_session_id(void)
70 {
71 uint64_t ret;
72
73 pthread_mutex_lock(&next_session_id_lock);
74 ret = ++_next_session_id;
75 pthread_mutex_unlock(&next_session_id_lock);
76 return ret;
77 }
78
79 static void copy_channel_attr_to_ustctl(
80 struct ustctl_consumer_channel_attr *attr,
81 struct lttng_ust_channel_attr *uattr)
82 {
83 /* Copy event attributes since the layout is different. */
84 attr->subbuf_size = uattr->subbuf_size;
85 attr->num_subbuf = uattr->num_subbuf;
86 attr->overwrite = uattr->overwrite;
87 attr->switch_timer_interval = uattr->switch_timer_interval;
88 attr->read_timer_interval = uattr->read_timer_interval;
89 attr->output = uattr->output;
90 attr->blocking_timeout = uattr->u.s.blocking_timeout;
91 }
92
93 /*
94 * Match function for the hash table lookup.
95 *
96 * It matches an ust app event based on three attributes which are the event
97 * name, the filter bytecode and the loglevel.
98 */
99 static int ht_match_ust_app_event(struct cds_lfht_node *node, const void *_key)
100 {
101 struct ust_app_event *event;
102 const struct ust_app_ht_key *key;
103 int ev_loglevel_value;
104
105 assert(node);
106 assert(_key);
107
108 event = caa_container_of(node, struct ust_app_event, node.node);
109 key = _key;
110 ev_loglevel_value = event->attr.loglevel;
111
112 /* Match the 4 elements of the key: name, filter, loglevel, exclusions */
113
114 /* Event name */
115 if (strncmp(event->attr.name, key->name, sizeof(event->attr.name)) != 0) {
116 goto no_match;
117 }
118
119 /* Event loglevel. */
120 if (ev_loglevel_value != key->loglevel_type) {
121 if (event->attr.loglevel_type == LTTNG_UST_LOGLEVEL_ALL
122 && key->loglevel_type == 0 &&
123 ev_loglevel_value == -1) {
124 /*
125 * Match is accepted. This is because on event creation, the
126 * loglevel is set to -1 if the event loglevel type is ALL so 0 and
127 * -1 are accepted for this loglevel type since 0 is the one set by
128 * the API when receiving an enable event.
129 */
130 } else {
131 goto no_match;
132 }
133 }
134
135 /* One of the filters is NULL, fail. */
136 if ((key->filter && !event->filter) || (!key->filter && event->filter)) {
137 goto no_match;
138 }
139
140 if (key->filter && event->filter) {
141 /* Both filters exists, check length followed by the bytecode. */
142 if (event->filter->len != key->filter->len ||
143 memcmp(event->filter->data, key->filter->data,
144 event->filter->len) != 0) {
145 goto no_match;
146 }
147 }
148
149 /* One of the exclusions is NULL, fail. */
150 if ((key->exclusion && !event->exclusion) || (!key->exclusion && event->exclusion)) {
151 goto no_match;
152 }
153
154 if (key->exclusion && event->exclusion) {
155 /* Both exclusions exists, check count followed by the names. */
156 if (event->exclusion->count != key->exclusion->count ||
157 memcmp(event->exclusion->names, key->exclusion->names,
158 event->exclusion->count * LTTNG_UST_SYM_NAME_LEN) != 0) {
159 goto no_match;
160 }
161 }
162
163
164 /* Match. */
165 return 1;
166
167 no_match:
168 return 0;
169 }
170
171 /*
172 * Unique add of an ust app event in the given ht. This uses the custom
173 * ht_match_ust_app_event match function and the event name as hash.
174 */
175 static void add_unique_ust_app_event(struct ust_app_channel *ua_chan,
176 struct ust_app_event *event)
177 {
178 struct cds_lfht_node *node_ptr;
179 struct ust_app_ht_key key;
180 struct lttng_ht *ht;
181
182 assert(ua_chan);
183 assert(ua_chan->events);
184 assert(event);
185
186 ht = ua_chan->events;
187 key.name = event->attr.name;
188 key.filter = event->filter;
189 key.loglevel_type = event->attr.loglevel;
190 key.exclusion = event->exclusion;
191
192 node_ptr = cds_lfht_add_unique(ht->ht,
193 ht->hash_fct(event->node.key, lttng_ht_seed),
194 ht_match_ust_app_event, &key, &event->node.node);
195 assert(node_ptr == &event->node.node);
196 }
197
198 /*
199 * Close the notify socket from the given RCU head object. This MUST be called
200 * through a call_rcu().
201 */
202 static void close_notify_sock_rcu(struct rcu_head *head)
203 {
204 int ret;
205 struct ust_app_notify_sock_obj *obj =
206 caa_container_of(head, struct ust_app_notify_sock_obj, head);
207
208 /* Must have a valid fd here. */
209 assert(obj->fd >= 0);
210
211 ret = close(obj->fd);
212 if (ret) {
213 ERR("close notify sock %d RCU", obj->fd);
214 }
215 lttng_fd_put(LTTNG_FD_APPS, 1);
216
217 free(obj);
218 }
219
220 /*
221 * Return the session registry according to the buffer type of the given
222 * session.
223 *
224 * A registry per UID object MUST exists before calling this function or else
225 * it assert() if not found. RCU read side lock must be acquired.
226 */
227 static struct ust_registry_session *get_session_registry(
228 struct ust_app_session *ua_sess)
229 {
230 struct ust_registry_session *registry = NULL;
231
232 assert(ua_sess);
233
234 switch (ua_sess->buffer_type) {
235 case LTTNG_BUFFER_PER_PID:
236 {
237 struct buffer_reg_pid *reg_pid = buffer_reg_pid_find(ua_sess->id);
238 if (!reg_pid) {
239 goto error;
240 }
241 registry = reg_pid->registry->reg.ust;
242 break;
243 }
244 case LTTNG_BUFFER_PER_UID:
245 {
246 struct buffer_reg_uid *reg_uid = buffer_reg_uid_find(
247 ua_sess->tracing_id, ua_sess->bits_per_long,
248 lttng_credentials_get_uid(&ua_sess->real_credentials));
249 if (!reg_uid) {
250 goto error;
251 }
252 registry = reg_uid->registry->reg.ust;
253 break;
254 }
255 default:
256 assert(0);
257 };
258
259 error:
260 return registry;
261 }
262
263 /*
264 * Delete ust context safely. RCU read lock must be held before calling
265 * this function.
266 */
267 static
268 void delete_ust_app_ctx(int sock, struct ust_app_ctx *ua_ctx,
269 struct ust_app *app)
270 {
271 int ret;
272
273 assert(ua_ctx);
274
275 if (ua_ctx->obj) {
276 pthread_mutex_lock(&app->sock_lock);
277 ret = ustctl_release_object(sock, ua_ctx->obj);
278 pthread_mutex_unlock(&app->sock_lock);
279 if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
280 ERR("UST app sock %d release ctx obj handle %d failed with ret %d",
281 sock, ua_ctx->obj->handle, ret);
282 }
283 free(ua_ctx->obj);
284 }
285 free(ua_ctx);
286 }
287
288 /*
289 * Delete ust app event safely. RCU read lock must be held before calling
290 * this function.
291 */
292 static
293 void delete_ust_app_event(int sock, struct ust_app_event *ua_event,
294 struct ust_app *app)
295 {
296 int ret;
297
298 assert(ua_event);
299
300 free(ua_event->filter);
301 if (ua_event->exclusion != NULL)
302 free(ua_event->exclusion);
303 if (ua_event->obj != NULL) {
304 pthread_mutex_lock(&app->sock_lock);
305 ret = ustctl_release_object(sock, ua_event->obj);
306 pthread_mutex_unlock(&app->sock_lock);
307 if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
308 ERR("UST app sock %d release event obj failed with ret %d",
309 sock, ret);
310 }
311 free(ua_event->obj);
312 }
313 free(ua_event);
314 }
315
316 /*
317 * Release ust data object of the given stream.
318 *
319 * Return 0 on success or else a negative value.
320 */
321 static int release_ust_app_stream(int sock, struct ust_app_stream *stream,
322 struct ust_app *app)
323 {
324 int ret = 0;
325
326 assert(stream);
327
328 if (stream->obj) {
329 pthread_mutex_lock(&app->sock_lock);
330 ret = ustctl_release_object(sock, stream->obj);
331 pthread_mutex_unlock(&app->sock_lock);
332 if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
333 ERR("UST app sock %d release stream obj failed with ret %d",
334 sock, ret);
335 }
336 lttng_fd_put(LTTNG_FD_APPS, 2);
337 free(stream->obj);
338 }
339
340 return ret;
341 }
342
343 /*
344 * Delete ust app stream safely. RCU read lock must be held before calling
345 * this function.
346 */
347 static
348 void delete_ust_app_stream(int sock, struct ust_app_stream *stream,
349 struct ust_app *app)
350 {
351 assert(stream);
352
353 (void) release_ust_app_stream(sock, stream, app);
354 free(stream);
355 }
356
357 /*
358 * We need to execute ht_destroy outside of RCU read-side critical
359 * section and outside of call_rcu thread, so we postpone its execution
360 * using ht_cleanup_push. It is simpler than to change the semantic of
361 * the many callers of delete_ust_app_session().
362 */
363 static
364 void delete_ust_app_channel_rcu(struct rcu_head *head)
365 {
366 struct ust_app_channel *ua_chan =
367 caa_container_of(head, struct ust_app_channel, rcu_head);
368
369 ht_cleanup_push(ua_chan->ctx);
370 ht_cleanup_push(ua_chan->events);
371 free(ua_chan);
372 }
373
374 /*
375 * Extract the lost packet or discarded events counter when the channel is
376 * being deleted and store the value in the parent channel so we can
377 * access it from lttng list and at stop/destroy.
378 *
379 * The session list lock must be held by the caller.
380 */
381 static
382 void save_per_pid_lost_discarded_counters(struct ust_app_channel *ua_chan)
383 {
384 uint64_t discarded = 0, lost = 0;
385 struct ltt_session *session;
386 struct ltt_ust_channel *uchan;
387
388 if (ua_chan->attr.type != LTTNG_UST_CHAN_PER_CPU) {
389 return;
390 }
391
392 rcu_read_lock();
393 session = session_find_by_id(ua_chan->session->tracing_id);
394 if (!session || !session->ust_session) {
395 /*
396 * Not finding the session is not an error because there are
397 * multiple ways the channels can be torn down.
398 *
399 * 1) The session daemon can initiate the destruction of the
400 * ust app session after receiving a destroy command or
401 * during its shutdown/teardown.
402 * 2) The application, since we are in per-pid tracing, is
403 * unregistering and tearing down its ust app session.
404 *
405 * Both paths are protected by the session list lock which
406 * ensures that the accounting of lost packets and discarded
407 * events is done exactly once. The session is then unpublished
408 * from the session list, resulting in this condition.
409 */
410 goto end;
411 }
412
413 if (ua_chan->attr.overwrite) {
414 consumer_get_lost_packets(ua_chan->session->tracing_id,
415 ua_chan->key, session->ust_session->consumer,
416 &lost);
417 } else {
418 consumer_get_discarded_events(ua_chan->session->tracing_id,
419 ua_chan->key, session->ust_session->consumer,
420 &discarded);
421 }
422 uchan = trace_ust_find_channel_by_name(
423 session->ust_session->domain_global.channels,
424 ua_chan->name);
425 if (!uchan) {
426 ERR("Missing UST channel to store discarded counters");
427 goto end;
428 }
429
430 uchan->per_pid_closed_app_discarded += discarded;
431 uchan->per_pid_closed_app_lost += lost;
432
433 end:
434 rcu_read_unlock();
435 if (session) {
436 session_put(session);
437 }
438 }
439
440 /*
441 * Delete ust app channel safely. RCU read lock must be held before calling
442 * this function.
443 *
444 * The session list lock must be held by the caller.
445 */
446 static
447 void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan,
448 struct ust_app *app)
449 {
450 int ret;
451 struct lttng_ht_iter iter;
452 struct ust_app_event *ua_event;
453 struct ust_app_ctx *ua_ctx;
454 struct ust_app_stream *stream, *stmp;
455 struct ust_registry_session *registry;
456
457 assert(ua_chan);
458
459 DBG3("UST app deleting channel %s", ua_chan->name);
460
461 /* Wipe stream */
462 cds_list_for_each_entry_safe(stream, stmp, &ua_chan->streams.head, list) {
463 cds_list_del(&stream->list);
464 delete_ust_app_stream(sock, stream, app);
465 }
466
467 /* Wipe context */
468 cds_lfht_for_each_entry(ua_chan->ctx->ht, &iter.iter, ua_ctx, node.node) {
469 cds_list_del(&ua_ctx->list);
470 ret = lttng_ht_del(ua_chan->ctx, &iter);
471 assert(!ret);
472 delete_ust_app_ctx(sock, ua_ctx, app);
473 }
474
475 /* Wipe events */
476 cds_lfht_for_each_entry(ua_chan->events->ht, &iter.iter, ua_event,
477 node.node) {
478 ret = lttng_ht_del(ua_chan->events, &iter);
479 assert(!ret);
480 delete_ust_app_event(sock, ua_event, app);
481 }
482
483 if (ua_chan->session->buffer_type == LTTNG_BUFFER_PER_PID) {
484 /* Wipe and free registry from session registry. */
485 registry = get_session_registry(ua_chan->session);
486 if (registry) {
487 ust_registry_channel_del_free(registry, ua_chan->key,
488 sock >= 0);
489 }
490 /*
491 * A negative socket can be used by the caller when
492 * cleaning-up a ua_chan in an error path. Skip the
493 * accounting in this case.
494 */
495 if (sock >= 0) {
496 save_per_pid_lost_discarded_counters(ua_chan);
497 }
498 }
499
500 if (ua_chan->obj != NULL) {
501 /* Remove channel from application UST object descriptor. */
502 iter.iter.node = &ua_chan->ust_objd_node.node;
503 ret = lttng_ht_del(app->ust_objd, &iter);
504 assert(!ret);
505 pthread_mutex_lock(&app->sock_lock);
506 ret = ustctl_release_object(sock, ua_chan->obj);
507 pthread_mutex_unlock(&app->sock_lock);
508 if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
509 ERR("UST app sock %d release channel obj failed with ret %d",
510 sock, ret);
511 }
512 lttng_fd_put(LTTNG_FD_APPS, 1);
513 free(ua_chan->obj);
514 }
515 call_rcu(&ua_chan->rcu_head, delete_ust_app_channel_rcu);
516 }
517
518 int ust_app_register_done(struct ust_app *app)
519 {
520 int ret;
521
522 pthread_mutex_lock(&app->sock_lock);
523 ret = ustctl_register_done(app->sock);
524 pthread_mutex_unlock(&app->sock_lock);
525 return ret;
526 }
527
528 int ust_app_release_object(struct ust_app *app, struct lttng_ust_object_data *data)
529 {
530 int ret, sock;
531
532 if (app) {
533 pthread_mutex_lock(&app->sock_lock);
534 sock = app->sock;
535 } else {
536 sock = -1;
537 }
538 ret = ustctl_release_object(sock, data);
539 if (app) {
540 pthread_mutex_unlock(&app->sock_lock);
541 }
542 return ret;
543 }
544
545 /*
546 * Push metadata to consumer socket.
547 *
548 * RCU read-side lock must be held to guarantee existance of socket.
549 * Must be called with the ust app session lock held.
550 * Must be called with the registry lock held.
551 *
552 * On success, return the len of metadata pushed or else a negative value.
553 * Returning a -EPIPE return value means we could not send the metadata,
554 * but it can be caused by recoverable errors (e.g. the application has
555 * terminated concurrently).
556 */
557 ssize_t ust_app_push_metadata(struct ust_registry_session *registry,
558 struct consumer_socket *socket, int send_zero_data)
559 {
560 int ret;
561 char *metadata_str = NULL;
562 size_t len, offset, new_metadata_len_sent;
563 ssize_t ret_val;
564 uint64_t metadata_key, metadata_version;
565
566 assert(registry);
567 assert(socket);
568
569 metadata_key = registry->metadata_key;
570
571 /*
572 * Means that no metadata was assigned to the session. This can
573 * happens if no start has been done previously.
574 */
575 if (!metadata_key) {
576 return 0;
577 }
578
579 offset = registry->metadata_len_sent;
580 len = registry->metadata_len - registry->metadata_len_sent;
581 new_metadata_len_sent = registry->metadata_len;
582 metadata_version = registry->metadata_version;
583 if (len == 0) {
584 DBG3("No metadata to push for metadata key %" PRIu64,
585 registry->metadata_key);
586 ret_val = len;
587 if (send_zero_data) {
588 DBG("No metadata to push");
589 goto push_data;
590 }
591 goto end;
592 }
593
594 /* Allocate only what we have to send. */
595 metadata_str = zmalloc(len);
596 if (!metadata_str) {
597 PERROR("zmalloc ust app metadata string");
598 ret_val = -ENOMEM;
599 goto error;
600 }
601 /* Copy what we haven't sent out. */
602 memcpy(metadata_str, registry->metadata + offset, len);
603
604 push_data:
605 pthread_mutex_unlock(&registry->lock);
606 /*
607 * We need to unlock the registry while we push metadata to
608 * break a circular dependency between the consumerd metadata
609 * lock and the sessiond registry lock. Indeed, pushing metadata
610 * to the consumerd awaits that it gets pushed all the way to
611 * relayd, but doing so requires grabbing the metadata lock. If
612 * a concurrent metadata request is being performed by
613 * consumerd, this can try to grab the registry lock on the
614 * sessiond while holding the metadata lock on the consumer
615 * daemon. Those push and pull schemes are performed on two
616 * different bidirectionnal communication sockets.
617 */
618 ret = consumer_push_metadata(socket, metadata_key,
619 metadata_str, len, offset, metadata_version);
620 pthread_mutex_lock(&registry->lock);
621 if (ret < 0) {
622 /*
623 * There is an acceptable race here between the registry
624 * metadata key assignment and the creation on the
625 * consumer. The session daemon can concurrently push
626 * metadata for this registry while being created on the
627 * consumer since the metadata key of the registry is
628 * assigned *before* it is setup to avoid the consumer
629 * to ask for metadata that could possibly be not found
630 * in the session daemon.
631 *
632 * The metadata will get pushed either by the session
633 * being stopped or the consumer requesting metadata if
634 * that race is triggered.
635 */
636 if (ret == -LTTCOMM_CONSUMERD_CHANNEL_FAIL) {
637 ret = 0;
638 } else {
639 ERR("Error pushing metadata to consumer");
640 }
641 ret_val = ret;
642 goto error_push;
643 } else {
644 /*
645 * Metadata may have been concurrently pushed, since
646 * we're not holding the registry lock while pushing to
647 * consumer. This is handled by the fact that we send
648 * the metadata content, size, and the offset at which
649 * that metadata belongs. This may arrive out of order
650 * on the consumer side, and the consumer is able to
651 * deal with overlapping fragments. The consumer
652 * supports overlapping fragments, which must be
653 * contiguous starting from offset 0. We keep the
654 * largest metadata_len_sent value of the concurrent
655 * send.
656 */
657 registry->metadata_len_sent =
658 max_t(size_t, registry->metadata_len_sent,
659 new_metadata_len_sent);
660 }
661 free(metadata_str);
662 return len;
663
664 end:
665 error:
666 if (ret_val) {
667 /*
668 * On error, flag the registry that the metadata is
669 * closed. We were unable to push anything and this
670 * means that either the consumer is not responding or
671 * the metadata cache has been destroyed on the
672 * consumer.
673 */
674 registry->metadata_closed = 1;
675 }
676 error_push:
677 free(metadata_str);
678 return ret_val;
679 }
680
681 /*
682 * For a given application and session, push metadata to consumer.
683 * Either sock or consumer is required : if sock is NULL, the default
684 * socket to send the metadata is retrieved from consumer, if sock
685 * is not NULL we use it to send the metadata.
686 * RCU read-side lock must be held while calling this function,
687 * therefore ensuring existance of registry. It also ensures existance
688 * of socket throughout this function.
689 *
690 * Return 0 on success else a negative error.
691 * Returning a -EPIPE return value means we could not send the metadata,
692 * but it can be caused by recoverable errors (e.g. the application has
693 * terminated concurrently).
694 */
695 static int push_metadata(struct ust_registry_session *registry,
696 struct consumer_output *consumer)
697 {
698 int ret_val;
699 ssize_t ret;
700 struct consumer_socket *socket;
701
702 assert(registry);
703 assert(consumer);
704
705 pthread_mutex_lock(&registry->lock);
706 if (registry->metadata_closed) {
707 ret_val = -EPIPE;
708 goto error;
709 }
710
711 /* Get consumer socket to use to push the metadata.*/
712 socket = consumer_find_socket_by_bitness(registry->bits_per_long,
713 consumer);
714 if (!socket) {
715 ret_val = -1;
716 goto error;
717 }
718
719 ret = ust_app_push_metadata(registry, socket, 0);
720 if (ret < 0) {
721 ret_val = ret;
722 goto error;
723 }
724 pthread_mutex_unlock(&registry->lock);
725 return 0;
726
727 error:
728 pthread_mutex_unlock(&registry->lock);
729 return ret_val;
730 }
731
732 /*
733 * Send to the consumer a close metadata command for the given session. Once
734 * done, the metadata channel is deleted and the session metadata pointer is
735 * nullified. The session lock MUST be held unless the application is
736 * in the destroy path.
737 *
738 * Do not hold the registry lock while communicating with the consumerd, because
739 * doing so causes inter-process deadlocks between consumerd and sessiond with
740 * the metadata request notification.
741 *
742 * Return 0 on success else a negative value.
743 */
744 static int close_metadata(struct ust_registry_session *registry,
745 struct consumer_output *consumer)
746 {
747 int ret;
748 struct consumer_socket *socket;
749 uint64_t metadata_key;
750 bool registry_was_already_closed;
751
752 assert(registry);
753 assert(consumer);
754
755 rcu_read_lock();
756
757 pthread_mutex_lock(&registry->lock);
758 metadata_key = registry->metadata_key;
759 registry_was_already_closed = registry->metadata_closed;
760 if (metadata_key != 0) {
761 /*
762 * Metadata closed. Even on error this means that the consumer
763 * is not responding or not found so either way a second close
764 * should NOT be emit for this registry.
765 */
766 registry->metadata_closed = 1;
767 }
768 pthread_mutex_unlock(&registry->lock);
769
770 if (metadata_key == 0 || registry_was_already_closed) {
771 ret = 0;
772 goto end;
773 }
774
775 /* Get consumer socket to use to push the metadata.*/
776 socket = consumer_find_socket_by_bitness(registry->bits_per_long,
777 consumer);
778 if (!socket) {
779 ret = -1;
780 goto end;
781 }
782
783 ret = consumer_close_metadata(socket, metadata_key);
784 if (ret < 0) {
785 goto end;
786 }
787
788 end:
789 rcu_read_unlock();
790 return ret;
791 }
792
793 /*
794 * We need to execute ht_destroy outside of RCU read-side critical
795 * section and outside of call_rcu thread, so we postpone its execution
796 * using ht_cleanup_push. It is simpler than to change the semantic of
797 * the many callers of delete_ust_app_session().
798 */
799 static
800 void delete_ust_app_session_rcu(struct rcu_head *head)
801 {
802 struct ust_app_session *ua_sess =
803 caa_container_of(head, struct ust_app_session, rcu_head);
804
805 ht_cleanup_push(ua_sess->channels);
806 free(ua_sess);
807 }
808
809 /*
810 * Delete ust app session safely. RCU read lock must be held before calling
811 * this function.
812 *
813 * The session list lock must be held by the caller.
814 */
815 static
816 void delete_ust_app_session(int sock, struct ust_app_session *ua_sess,
817 struct ust_app *app)
818 {
819 int ret;
820 struct lttng_ht_iter iter;
821 struct ust_app_channel *ua_chan;
822 struct ust_registry_session *registry;
823
824 assert(ua_sess);
825
826 pthread_mutex_lock(&ua_sess->lock);
827
828 assert(!ua_sess->deleted);
829 ua_sess->deleted = true;
830
831 registry = get_session_registry(ua_sess);
832 /* Registry can be null on error path during initialization. */
833 if (registry) {
834 /* Push metadata for application before freeing the application. */
835 (void) push_metadata(registry, ua_sess->consumer);
836
837 /*
838 * Don't ask to close metadata for global per UID buffers. Close
839 * metadata only on destroy trace session in this case. Also, the
840 * previous push metadata could have flag the metadata registry to
841 * close so don't send a close command if closed.
842 */
843 if (ua_sess->buffer_type != LTTNG_BUFFER_PER_UID) {
844 /* And ask to close it for this session registry. */
845 (void) close_metadata(registry, ua_sess->consumer);
846 }
847 }
848
849 cds_lfht_for_each_entry(ua_sess->channels->ht, &iter.iter, ua_chan,
850 node.node) {
851 ret = lttng_ht_del(ua_sess->channels, &iter);
852 assert(!ret);
853 delete_ust_app_channel(sock, ua_chan, app);
854 }
855
856 /* In case of per PID, the registry is kept in the session. */
857 if (ua_sess->buffer_type == LTTNG_BUFFER_PER_PID) {
858 struct buffer_reg_pid *reg_pid = buffer_reg_pid_find(ua_sess->id);
859 if (reg_pid) {
860 /*
861 * Registry can be null on error path during
862 * initialization.
863 */
864 buffer_reg_pid_remove(reg_pid);
865 buffer_reg_pid_destroy(reg_pid);
866 }
867 }
868
869 if (ua_sess->handle != -1) {
870 pthread_mutex_lock(&app->sock_lock);
871 ret = ustctl_release_handle(sock, ua_sess->handle);
872 pthread_mutex_unlock(&app->sock_lock);
873 if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
874 ERR("UST app sock %d release session handle failed with ret %d",
875 sock, ret);
876 }
877 /* Remove session from application UST object descriptor. */
878 iter.iter.node = &ua_sess->ust_objd_node.node;
879 ret = lttng_ht_del(app->ust_sessions_objd, &iter);
880 assert(!ret);
881 }
882
883 pthread_mutex_unlock(&ua_sess->lock);
884
885 consumer_output_put(ua_sess->consumer);
886
887 call_rcu(&ua_sess->rcu_head, delete_ust_app_session_rcu);
888 }
889
890 /*
891 * Delete a traceable application structure from the global list. Never call
892 * this function outside of a call_rcu call.
893 *
894 * RCU read side lock should _NOT_ be held when calling this function.
895 */
896 static
897 void delete_ust_app(struct ust_app *app)
898 {
899 int ret, sock;
900 struct ust_app_session *ua_sess, *tmp_ua_sess;
901
902 /*
903 * The session list lock must be held during this function to guarantee
904 * the existence of ua_sess.
905 */
906 session_lock_list();
907 /* Delete ust app sessions info */
908 sock = app->sock;
909 app->sock = -1;
910
911 /* Wipe sessions */
912 cds_list_for_each_entry_safe(ua_sess, tmp_ua_sess, &app->teardown_head,
913 teardown_node) {
914 /* Free every object in the session and the session. */
915 rcu_read_lock();
916 delete_ust_app_session(sock, ua_sess, app);
917 rcu_read_unlock();
918 }
919
920 ht_cleanup_push(app->sessions);
921 ht_cleanup_push(app->ust_sessions_objd);
922 ht_cleanup_push(app->ust_objd);
923
924 /*
925 * Wait until we have deleted the application from the sock hash table
926 * before closing this socket, otherwise an application could re-use the
927 * socket ID and race with the teardown, using the same hash table entry.
928 *
929 * It's OK to leave the close in call_rcu. We want it to stay unique for
930 * all RCU readers that could run concurrently with unregister app,
931 * therefore we _need_ to only close that socket after a grace period. So
932 * it should stay in this RCU callback.
933 *
934 * This close() is a very important step of the synchronization model so
935 * every modification to this function must be carefully reviewed.
936 */
937 ret = close(sock);
938 if (ret) {
939 PERROR("close");
940 }
941 lttng_fd_put(LTTNG_FD_APPS, 1);
942
943 DBG2("UST app pid %d deleted", app->pid);
944 free(app);
945 session_unlock_list();
946 }
947
948 /*
949 * URCU intermediate call to delete an UST app.
950 */
951 static
952 void delete_ust_app_rcu(struct rcu_head *head)
953 {
954 struct lttng_ht_node_ulong *node =
955 caa_container_of(head, struct lttng_ht_node_ulong, head);
956 struct ust_app *app =
957 caa_container_of(node, struct ust_app, pid_n);
958
959 DBG3("Call RCU deleting app PID %d", app->pid);
960 delete_ust_app(app);
961 }
962
963 /*
964 * Delete the session from the application ht and delete the data structure by
965 * freeing every object inside and releasing them.
966 *
967 * The session list lock must be held by the caller.
968 */
969 static void destroy_app_session(struct ust_app *app,
970 struct ust_app_session *ua_sess)
971 {
972 int ret;
973 struct lttng_ht_iter iter;
974
975 assert(app);
976 assert(ua_sess);
977
978 iter.iter.node = &ua_sess->node.node;
979 ret = lttng_ht_del(app->sessions, &iter);
980 if (ret) {
981 /* Already scheduled for teardown. */
982 goto end;
983 }
984
985 /* Once deleted, free the data structure. */
986 delete_ust_app_session(app->sock, ua_sess, app);
987
988 end:
989 return;
990 }
991
992 /*
993 * Alloc new UST app session.
994 */
995 static
996 struct ust_app_session *alloc_ust_app_session(void)
997 {
998 struct ust_app_session *ua_sess;
999
1000 /* Init most of the default value by allocating and zeroing */
1001 ua_sess = zmalloc(sizeof(struct ust_app_session));
1002 if (ua_sess == NULL) {
1003 PERROR("malloc");
1004 goto error_free;
1005 }
1006
1007 ua_sess->handle = -1;
1008 ua_sess->channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
1009 ua_sess->metadata_attr.type = LTTNG_UST_CHAN_METADATA;
1010 pthread_mutex_init(&ua_sess->lock, NULL);
1011
1012 return ua_sess;
1013
1014 error_free:
1015 return NULL;
1016 }
1017
1018 /*
1019 * Alloc new UST app channel.
1020 */
1021 static
1022 struct ust_app_channel *alloc_ust_app_channel(const char *name,
1023 struct ust_app_session *ua_sess,
1024 struct lttng_ust_channel_attr *attr)
1025 {
1026 struct ust_app_channel *ua_chan;
1027
1028 /* Init most of the default value by allocating and zeroing */
1029 ua_chan = zmalloc(sizeof(struct ust_app_channel));
1030 if (ua_chan == NULL) {
1031 PERROR("malloc");
1032 goto error;
1033 }
1034
1035 /* Setup channel name */
1036 strncpy(ua_chan->name, name, sizeof(ua_chan->name));
1037 ua_chan->name[sizeof(ua_chan->name) - 1] = '\0';
1038
1039 ua_chan->enabled = 1;
1040 ua_chan->handle = -1;
1041 ua_chan->session = ua_sess;
1042 ua_chan->key = get_next_channel_key();
1043 ua_chan->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1044 ua_chan->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
1045 lttng_ht_node_init_str(&ua_chan->node, ua_chan->name);
1046
1047 CDS_INIT_LIST_HEAD(&ua_chan->streams.head);
1048 CDS_INIT_LIST_HEAD(&ua_chan->ctx_list);
1049
1050 /* Copy attributes */
1051 if (attr) {
1052 /* Translate from lttng_ust_channel to ustctl_consumer_channel_attr. */
1053 ua_chan->attr.subbuf_size = attr->subbuf_size;
1054 ua_chan->attr.num_subbuf = attr->num_subbuf;
1055 ua_chan->attr.overwrite = attr->overwrite;
1056 ua_chan->attr.switch_timer_interval = attr->switch_timer_interval;
1057 ua_chan->attr.read_timer_interval = attr->read_timer_interval;
1058 ua_chan->attr.output = attr->output;
1059 ua_chan->attr.blocking_timeout = attr->u.s.blocking_timeout;
1060 }
1061 /* By default, the channel is a per cpu channel. */
1062 ua_chan->attr.type = LTTNG_UST_CHAN_PER_CPU;
1063
1064 DBG3("UST app channel %s allocated", ua_chan->name);
1065
1066 return ua_chan;
1067
1068 error:
1069 return NULL;
1070 }
1071
1072 /*
1073 * Allocate and initialize a UST app stream.
1074 *
1075 * Return newly allocated stream pointer or NULL on error.
1076 */
1077 struct ust_app_stream *ust_app_alloc_stream(void)
1078 {
1079 struct ust_app_stream *stream = NULL;
1080
1081 stream = zmalloc(sizeof(*stream));
1082 if (stream == NULL) {
1083 PERROR("zmalloc ust app stream");
1084 goto error;
1085 }
1086
1087 /* Zero could be a valid value for a handle so flag it to -1. */
1088 stream->handle = -1;
1089
1090 error:
1091 return stream;
1092 }
1093
1094 /*
1095 * Alloc new UST app event.
1096 */
1097 static
1098 struct ust_app_event *alloc_ust_app_event(char *name,
1099 struct lttng_ust_event *attr)
1100 {
1101 struct ust_app_event *ua_event;
1102
1103 /* Init most of the default value by allocating and zeroing */
1104 ua_event = zmalloc(sizeof(struct ust_app_event));
1105 if (ua_event == NULL) {
1106 PERROR("Failed to allocate ust_app_event structure");
1107 goto error;
1108 }
1109
1110 ua_event->enabled = 1;
1111 strncpy(ua_event->name, name, sizeof(ua_event->name));
1112 ua_event->name[sizeof(ua_event->name) - 1] = '\0';
1113 lttng_ht_node_init_str(&ua_event->node, ua_event->name);
1114
1115 /* Copy attributes */
1116 if (attr) {
1117 memcpy(&ua_event->attr, attr, sizeof(ua_event->attr));
1118 }
1119
1120 DBG3("UST app event %s allocated", ua_event->name);
1121
1122 return ua_event;
1123
1124 error:
1125 return NULL;
1126 }
1127
1128 /*
1129 * Alloc new UST app context.
1130 */
1131 static
1132 struct ust_app_ctx *alloc_ust_app_ctx(struct lttng_ust_context_attr *uctx)
1133 {
1134 struct ust_app_ctx *ua_ctx;
1135
1136 ua_ctx = zmalloc(sizeof(struct ust_app_ctx));
1137 if (ua_ctx == NULL) {
1138 goto error;
1139 }
1140
1141 CDS_INIT_LIST_HEAD(&ua_ctx->list);
1142
1143 if (uctx) {
1144 memcpy(&ua_ctx->ctx, uctx, sizeof(ua_ctx->ctx));
1145 if (uctx->ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1146 char *provider_name = NULL, *ctx_name = NULL;
1147
1148 provider_name = strdup(uctx->u.app_ctx.provider_name);
1149 ctx_name = strdup(uctx->u.app_ctx.ctx_name);
1150 if (!provider_name || !ctx_name) {
1151 free(provider_name);
1152 free(ctx_name);
1153 goto error;
1154 }
1155
1156 ua_ctx->ctx.u.app_ctx.provider_name = provider_name;
1157 ua_ctx->ctx.u.app_ctx.ctx_name = ctx_name;
1158 }
1159 }
1160
1161 DBG3("UST app context %d allocated", ua_ctx->ctx.ctx);
1162 return ua_ctx;
1163 error:
1164 free(ua_ctx);
1165 return NULL;
1166 }
1167
1168 /*
1169 * Allocate a filter and copy the given original filter.
1170 *
1171 * Return allocated filter or NULL on error.
1172 */
1173 static struct lttng_filter_bytecode *copy_filter_bytecode(
1174 struct lttng_filter_bytecode *orig_f)
1175 {
1176 struct lttng_filter_bytecode *filter = NULL;
1177
1178 /* Copy filter bytecode */
1179 filter = zmalloc(sizeof(*filter) + orig_f->len);
1180 if (!filter) {
1181 PERROR("zmalloc alloc filter bytecode");
1182 goto error;
1183 }
1184
1185 memcpy(filter, orig_f, sizeof(*filter) + orig_f->len);
1186
1187 error:
1188 return filter;
1189 }
1190
1191 /*
1192 * Create a liblttng-ust filter bytecode from given bytecode.
1193 *
1194 * Return allocated filter or NULL on error.
1195 */
1196 static struct lttng_ust_filter_bytecode *create_ust_bytecode_from_bytecode(
1197 struct lttng_filter_bytecode *orig_f)
1198 {
1199 struct lttng_ust_filter_bytecode *filter = NULL;
1200
1201 /* Copy filter bytecode */
1202 filter = zmalloc(sizeof(*filter) + orig_f->len);
1203 if (!filter) {
1204 PERROR("zmalloc alloc ust filter bytecode");
1205 goto error;
1206 }
1207
1208 assert(sizeof(struct lttng_filter_bytecode) ==
1209 sizeof(struct lttng_ust_filter_bytecode));
1210 memcpy(filter, orig_f, sizeof(*filter) + orig_f->len);
1211 error:
1212 return filter;
1213 }
1214
1215 /*
1216 * Find an ust_app using the sock and return it. RCU read side lock must be
1217 * held before calling this helper function.
1218 */
1219 struct ust_app *ust_app_find_by_sock(int sock)
1220 {
1221 struct lttng_ht_node_ulong *node;
1222 struct lttng_ht_iter iter;
1223
1224 lttng_ht_lookup(ust_app_ht_by_sock, (void *)((unsigned long) sock), &iter);
1225 node = lttng_ht_iter_get_node_ulong(&iter);
1226 if (node == NULL) {
1227 DBG2("UST app find by sock %d not found", sock);
1228 goto error;
1229 }
1230
1231 return caa_container_of(node, struct ust_app, sock_n);
1232
1233 error:
1234 return NULL;
1235 }
1236
1237 /*
1238 * Find an ust_app using the notify sock and return it. RCU read side lock must
1239 * be held before calling this helper function.
1240 */
1241 static struct ust_app *find_app_by_notify_sock(int sock)
1242 {
1243 struct lttng_ht_node_ulong *node;
1244 struct lttng_ht_iter iter;
1245
1246 lttng_ht_lookup(ust_app_ht_by_notify_sock, (void *)((unsigned long) sock),
1247 &iter);
1248 node = lttng_ht_iter_get_node_ulong(&iter);
1249 if (node == NULL) {
1250 DBG2("UST app find by notify sock %d not found", sock);
1251 goto error;
1252 }
1253
1254 return caa_container_of(node, struct ust_app, notify_sock_n);
1255
1256 error:
1257 return NULL;
1258 }
1259
1260 /*
1261 * Lookup for an ust app event based on event name, filter bytecode and the
1262 * event loglevel.
1263 *
1264 * Return an ust_app_event object or NULL on error.
1265 */
1266 static struct ust_app_event *find_ust_app_event(struct lttng_ht *ht,
1267 const char *name, const struct lttng_filter_bytecode *filter,
1268 int loglevel_value,
1269 const struct lttng_event_exclusion *exclusion)
1270 {
1271 struct lttng_ht_iter iter;
1272 struct lttng_ht_node_str *node;
1273 struct ust_app_event *event = NULL;
1274 struct ust_app_ht_key key;
1275
1276 assert(name);
1277 assert(ht);
1278
1279 /* Setup key for event lookup. */
1280 key.name = name;
1281 key.filter = filter;
1282 key.loglevel_type = loglevel_value;
1283 /* lttng_event_exclusion and lttng_ust_event_exclusion structures are similar */
1284 key.exclusion = exclusion;
1285
1286 /* Lookup using the event name as hash and a custom match fct. */
1287 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
1288 ht_match_ust_app_event, &key, &iter.iter);
1289 node = lttng_ht_iter_get_node_str(&iter);
1290 if (node == NULL) {
1291 goto end;
1292 }
1293
1294 event = caa_container_of(node, struct ust_app_event, node);
1295
1296 end:
1297 return event;
1298 }
1299
1300 /*
1301 * Create the channel context on the tracer.
1302 *
1303 * Called with UST app session lock held.
1304 */
1305 static
1306 int create_ust_channel_context(struct ust_app_channel *ua_chan,
1307 struct ust_app_ctx *ua_ctx, struct ust_app *app)
1308 {
1309 int ret;
1310
1311 health_code_update();
1312
1313 pthread_mutex_lock(&app->sock_lock);
1314 ret = ustctl_add_context(app->sock, &ua_ctx->ctx,
1315 ua_chan->obj, &ua_ctx->obj);
1316 pthread_mutex_unlock(&app->sock_lock);
1317 if (ret < 0) {
1318 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1319 ERR("UST app create channel context failed for app (pid: %d) "
1320 "with ret %d", app->pid, ret);
1321 } else {
1322 /*
1323 * This is normal behavior, an application can die during the
1324 * creation process. Don't report an error so the execution can
1325 * continue normally.
1326 */
1327 ret = 0;
1328 DBG3("UST app add context failed. Application is dead.");
1329 }
1330 goto error;
1331 }
1332
1333 ua_ctx->handle = ua_ctx->obj->handle;
1334
1335 DBG2("UST app context handle %d created successfully for channel %s",
1336 ua_ctx->handle, ua_chan->name);
1337
1338 error:
1339 health_code_update();
1340 return ret;
1341 }
1342
1343 /*
1344 * Set the filter on the tracer.
1345 */
1346 static
1347 int set_ust_event_filter(struct ust_app_event *ua_event,
1348 struct ust_app *app)
1349 {
1350 int ret;
1351 struct lttng_ust_filter_bytecode *ust_bytecode = NULL;
1352
1353 health_code_update();
1354
1355 if (!ua_event->filter) {
1356 ret = 0;
1357 goto error;
1358 }
1359
1360 ust_bytecode = create_ust_bytecode_from_bytecode(ua_event->filter);
1361 if (!ust_bytecode) {
1362 ret = -LTTNG_ERR_NOMEM;
1363 goto error;
1364 }
1365 pthread_mutex_lock(&app->sock_lock);
1366 ret = ustctl_set_filter(app->sock, ust_bytecode,
1367 ua_event->obj);
1368 pthread_mutex_unlock(&app->sock_lock);
1369 if (ret < 0) {
1370 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1371 ERR("UST app event %s filter failed for app (pid: %d) "
1372 "with ret %d", ua_event->attr.name, app->pid, ret);
1373 } else {
1374 /*
1375 * This is normal behavior, an application can die during the
1376 * creation process. Don't report an error so the execution can
1377 * continue normally.
1378 */
1379 ret = 0;
1380 DBG3("UST app filter event failed. Application is dead.");
1381 }
1382 goto error;
1383 }
1384
1385 DBG2("UST filter set successfully for event %s", ua_event->name);
1386
1387 error:
1388 health_code_update();
1389 free(ust_bytecode);
1390 return ret;
1391 }
1392
1393 static
1394 struct lttng_ust_event_exclusion *create_ust_exclusion_from_exclusion(
1395 struct lttng_event_exclusion *exclusion)
1396 {
1397 struct lttng_ust_event_exclusion *ust_exclusion = NULL;
1398 size_t exclusion_alloc_size = sizeof(struct lttng_ust_event_exclusion) +
1399 LTTNG_UST_SYM_NAME_LEN * exclusion->count;
1400
1401 ust_exclusion = zmalloc(exclusion_alloc_size);
1402 if (!ust_exclusion) {
1403 PERROR("malloc");
1404 goto end;
1405 }
1406
1407 assert(sizeof(struct lttng_event_exclusion) ==
1408 sizeof(struct lttng_ust_event_exclusion));
1409 memcpy(ust_exclusion, exclusion, exclusion_alloc_size);
1410 end:
1411 return ust_exclusion;
1412 }
1413
1414 /*
1415 * Set event exclusions on the tracer.
1416 */
1417 static
1418 int set_ust_event_exclusion(struct ust_app_event *ua_event,
1419 struct ust_app *app)
1420 {
1421 int ret;
1422 struct lttng_ust_event_exclusion *ust_exclusion = NULL;
1423
1424 health_code_update();
1425
1426 if (!ua_event->exclusion || !ua_event->exclusion->count) {
1427 ret = 0;
1428 goto error;
1429 }
1430
1431 ust_exclusion = create_ust_exclusion_from_exclusion(
1432 ua_event->exclusion);
1433 if (!ust_exclusion) {
1434 ret = -LTTNG_ERR_NOMEM;
1435 goto error;
1436 }
1437 pthread_mutex_lock(&app->sock_lock);
1438 ret = ustctl_set_exclusion(app->sock, ust_exclusion, ua_event->obj);
1439 pthread_mutex_unlock(&app->sock_lock);
1440 if (ret < 0) {
1441 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1442 ERR("UST app event %s exclusions failed for app (pid: %d) "
1443 "with ret %d", ua_event->attr.name, app->pid, ret);
1444 } else {
1445 /*
1446 * This is normal behavior, an application can die during the
1447 * creation process. Don't report an error so the execution can
1448 * continue normally.
1449 */
1450 ret = 0;
1451 DBG3("UST app event exclusion failed. Application is dead.");
1452 }
1453 goto error;
1454 }
1455
1456 DBG2("UST exclusion set successfully for event %s", ua_event->name);
1457
1458 error:
1459 health_code_update();
1460 free(ust_exclusion);
1461 return ret;
1462 }
1463
1464 /*
1465 * Disable the specified event on to UST tracer for the UST session.
1466 */
1467 static int disable_ust_event(struct ust_app *app,
1468 struct ust_app_session *ua_sess, struct ust_app_event *ua_event)
1469 {
1470 int ret;
1471
1472 health_code_update();
1473
1474 pthread_mutex_lock(&app->sock_lock);
1475 ret = ustctl_disable(app->sock, ua_event->obj);
1476 pthread_mutex_unlock(&app->sock_lock);
1477 if (ret < 0) {
1478 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1479 ERR("UST app event %s disable failed for app (pid: %d) "
1480 "and session handle %d with ret %d",
1481 ua_event->attr.name, app->pid, ua_sess->handle, ret);
1482 } else {
1483 /*
1484 * This is normal behavior, an application can die during the
1485 * creation process. Don't report an error so the execution can
1486 * continue normally.
1487 */
1488 ret = 0;
1489 DBG3("UST app disable event failed. Application is dead.");
1490 }
1491 goto error;
1492 }
1493
1494 DBG2("UST app event %s disabled successfully for app (pid: %d)",
1495 ua_event->attr.name, app->pid);
1496
1497 error:
1498 health_code_update();
1499 return ret;
1500 }
1501
1502 /*
1503 * Disable the specified channel on to UST tracer for the UST session.
1504 */
1505 static int disable_ust_channel(struct ust_app *app,
1506 struct ust_app_session *ua_sess, struct ust_app_channel *ua_chan)
1507 {
1508 int ret;
1509
1510 health_code_update();
1511
1512 pthread_mutex_lock(&app->sock_lock);
1513 ret = ustctl_disable(app->sock, ua_chan->obj);
1514 pthread_mutex_unlock(&app->sock_lock);
1515 if (ret < 0) {
1516 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1517 ERR("UST app channel %s disable failed for app (pid: %d) "
1518 "and session handle %d with ret %d",
1519 ua_chan->name, app->pid, ua_sess->handle, ret);
1520 } else {
1521 /*
1522 * This is normal behavior, an application can die during the
1523 * creation process. Don't report an error so the execution can
1524 * continue normally.
1525 */
1526 ret = 0;
1527 DBG3("UST app disable channel failed. Application is dead.");
1528 }
1529 goto error;
1530 }
1531
1532 DBG2("UST app channel %s disabled successfully for app (pid: %d)",
1533 ua_chan->name, app->pid);
1534
1535 error:
1536 health_code_update();
1537 return ret;
1538 }
1539
1540 /*
1541 * Enable the specified channel on to UST tracer for the UST session.
1542 */
1543 static int enable_ust_channel(struct ust_app *app,
1544 struct ust_app_session *ua_sess, struct ust_app_channel *ua_chan)
1545 {
1546 int ret;
1547
1548 health_code_update();
1549
1550 pthread_mutex_lock(&app->sock_lock);
1551 ret = ustctl_enable(app->sock, ua_chan->obj);
1552 pthread_mutex_unlock(&app->sock_lock);
1553 if (ret < 0) {
1554 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1555 ERR("UST app channel %s enable failed for app (pid: %d) "
1556 "and session handle %d with ret %d",
1557 ua_chan->name, app->pid, ua_sess->handle, ret);
1558 } else {
1559 /*
1560 * This is normal behavior, an application can die during the
1561 * creation process. Don't report an error so the execution can
1562 * continue normally.
1563 */
1564 ret = 0;
1565 DBG3("UST app enable channel failed. Application is dead.");
1566 }
1567 goto error;
1568 }
1569
1570 ua_chan->enabled = 1;
1571
1572 DBG2("UST app channel %s enabled successfully for app (pid: %d)",
1573 ua_chan->name, app->pid);
1574
1575 error:
1576 health_code_update();
1577 return ret;
1578 }
1579
1580 /*
1581 * Enable the specified event on to UST tracer for the UST session.
1582 */
1583 static int enable_ust_event(struct ust_app *app,
1584 struct ust_app_session *ua_sess, struct ust_app_event *ua_event)
1585 {
1586 int ret;
1587
1588 health_code_update();
1589
1590 pthread_mutex_lock(&app->sock_lock);
1591 ret = ustctl_enable(app->sock, ua_event->obj);
1592 pthread_mutex_unlock(&app->sock_lock);
1593 if (ret < 0) {
1594 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1595 ERR("UST app event %s enable failed for app (pid: %d) "
1596 "and session handle %d with ret %d",
1597 ua_event->attr.name, app->pid, ua_sess->handle, ret);
1598 } else {
1599 /*
1600 * This is normal behavior, an application can die during the
1601 * creation process. Don't report an error so the execution can
1602 * continue normally.
1603 */
1604 ret = 0;
1605 DBG3("UST app enable event failed. Application is dead.");
1606 }
1607 goto error;
1608 }
1609
1610 DBG2("UST app event %s enabled successfully for app (pid: %d)",
1611 ua_event->attr.name, app->pid);
1612
1613 error:
1614 health_code_update();
1615 return ret;
1616 }
1617
1618 /*
1619 * Send channel and stream buffer to application.
1620 *
1621 * Return 0 on success. On error, a negative value is returned.
1622 */
1623 static int send_channel_pid_to_ust(struct ust_app *app,
1624 struct ust_app_session *ua_sess, struct ust_app_channel *ua_chan)
1625 {
1626 int ret;
1627 struct ust_app_stream *stream, *stmp;
1628
1629 assert(app);
1630 assert(ua_sess);
1631 assert(ua_chan);
1632
1633 health_code_update();
1634
1635 DBG("UST app sending channel %s to UST app sock %d", ua_chan->name,
1636 app->sock);
1637
1638 /* Send channel to the application. */
1639 ret = ust_consumer_send_channel_to_ust(app, ua_sess, ua_chan);
1640 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
1641 ret = -ENOTCONN; /* Caused by app exiting. */
1642 goto error;
1643 } else if (ret < 0) {
1644 goto error;
1645 }
1646
1647 health_code_update();
1648
1649 /* Send all streams to application. */
1650 cds_list_for_each_entry_safe(stream, stmp, &ua_chan->streams.head, list) {
1651 ret = ust_consumer_send_stream_to_ust(app, ua_chan, stream);
1652 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
1653 ret = -ENOTCONN; /* Caused by app exiting. */
1654 goto error;
1655 } else if (ret < 0) {
1656 goto error;
1657 }
1658 /* We don't need the stream anymore once sent to the tracer. */
1659 cds_list_del(&stream->list);
1660 delete_ust_app_stream(-1, stream, app);
1661 }
1662 /* Flag the channel that it is sent to the application. */
1663 ua_chan->is_sent = 1;
1664
1665 error:
1666 health_code_update();
1667 return ret;
1668 }
1669
1670 /*
1671 * Create the specified event onto the UST tracer for a UST session.
1672 *
1673 * Should be called with session mutex held.
1674 */
1675 static
1676 int create_ust_event(struct ust_app *app, struct ust_app_session *ua_sess,
1677 struct ust_app_channel *ua_chan, struct ust_app_event *ua_event)
1678 {
1679 int ret = 0;
1680
1681 health_code_update();
1682
1683 /* Create UST event on tracer */
1684 pthread_mutex_lock(&app->sock_lock);
1685 ret = ustctl_create_event(app->sock, &ua_event->attr, ua_chan->obj,
1686 &ua_event->obj);
1687 pthread_mutex_unlock(&app->sock_lock);
1688 if (ret < 0) {
1689 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
1690 abort();
1691 ERR("Error ustctl create event %s for app pid: %d with ret %d",
1692 ua_event->attr.name, app->pid, ret);
1693 } else {
1694 /*
1695 * This is normal behavior, an application can die during the
1696 * creation process. Don't report an error so the execution can
1697 * continue normally.
1698 */
1699 ret = 0;
1700 DBG3("UST app create event failed. Application is dead.");
1701 }
1702 goto error;
1703 }
1704
1705 ua_event->handle = ua_event->obj->handle;
1706
1707 DBG2("UST app event %s created successfully for pid:%d",
1708 ua_event->attr.name, app->pid);
1709
1710 health_code_update();
1711
1712 /* Set filter if one is present. */
1713 if (ua_event->filter) {
1714 ret = set_ust_event_filter(ua_event, app);
1715 if (ret < 0) {
1716 goto error;
1717 }
1718 }
1719
1720 /* Set exclusions for the event */
1721 if (ua_event->exclusion) {
1722 ret = set_ust_event_exclusion(ua_event, app);
1723 if (ret < 0) {
1724 goto error;
1725 }
1726 }
1727
1728 /* If event not enabled, disable it on the tracer */
1729 if (ua_event->enabled) {
1730 /*
1731 * We now need to explicitly enable the event, since it
1732 * is now disabled at creation.
1733 */
1734 ret = enable_ust_event(app, ua_sess, ua_event);
1735 if (ret < 0) {
1736 /*
1737 * If we hit an EPERM, something is wrong with our enable call. If
1738 * we get an EEXIST, there is a problem on the tracer side since we
1739 * just created it.
1740 */
1741 switch (ret) {
1742 case -LTTNG_UST_ERR_PERM:
1743 /* Code flow problem */
1744 assert(0);
1745 case -LTTNG_UST_ERR_EXIST:
1746 /* It's OK for our use case. */
1747 ret = 0;
1748 break;
1749 default:
1750 break;
1751 }
1752 goto error;
1753 }
1754 }
1755
1756 error:
1757 health_code_update();
1758 return ret;
1759 }
1760
1761 /*
1762 * Copy data between an UST app event and a LTT event.
1763 */
1764 static void shadow_copy_event(struct ust_app_event *ua_event,
1765 struct ltt_ust_event *uevent)
1766 {
1767 size_t exclusion_alloc_size;
1768
1769 strncpy(ua_event->name, uevent->attr.name, sizeof(ua_event->name));
1770 ua_event->name[sizeof(ua_event->name) - 1] = '\0';
1771
1772 ua_event->enabled = uevent->enabled;
1773
1774 /* Copy event attributes */
1775 memcpy(&ua_event->attr, &uevent->attr, sizeof(ua_event->attr));
1776
1777 /* Copy filter bytecode */
1778 if (uevent->filter) {
1779 ua_event->filter = copy_filter_bytecode(uevent->filter);
1780 /* Filter might be NULL here in case of ENONEM. */
1781 }
1782
1783 /* Copy exclusion data */
1784 if (uevent->exclusion) {
1785 exclusion_alloc_size = sizeof(struct lttng_event_exclusion) +
1786 LTTNG_UST_SYM_NAME_LEN * uevent->exclusion->count;
1787 ua_event->exclusion = zmalloc(exclusion_alloc_size);
1788 if (ua_event->exclusion == NULL) {
1789 PERROR("malloc");
1790 } else {
1791 memcpy(ua_event->exclusion, uevent->exclusion,
1792 exclusion_alloc_size);
1793 }
1794 }
1795 }
1796
1797 /*
1798 * Copy data between an UST app channel and a LTT channel.
1799 */
1800 static void shadow_copy_channel(struct ust_app_channel *ua_chan,
1801 struct ltt_ust_channel *uchan)
1802 {
1803 DBG2("UST app shadow copy of channel %s started", ua_chan->name);
1804
1805 strncpy(ua_chan->name, uchan->name, sizeof(ua_chan->name));
1806 ua_chan->name[sizeof(ua_chan->name) - 1] = '\0';
1807
1808 ua_chan->tracefile_size = uchan->tracefile_size;
1809 ua_chan->tracefile_count = uchan->tracefile_count;
1810
1811 /* Copy event attributes since the layout is different. */
1812 ua_chan->attr.subbuf_size = uchan->attr.subbuf_size;
1813 ua_chan->attr.num_subbuf = uchan->attr.num_subbuf;
1814 ua_chan->attr.overwrite = uchan->attr.overwrite;
1815 ua_chan->attr.switch_timer_interval = uchan->attr.switch_timer_interval;
1816 ua_chan->attr.read_timer_interval = uchan->attr.read_timer_interval;
1817 ua_chan->monitor_timer_interval = uchan->monitor_timer_interval;
1818 ua_chan->attr.output = uchan->attr.output;
1819 ua_chan->attr.blocking_timeout = uchan->attr.u.s.blocking_timeout;
1820
1821 /*
1822 * Note that the attribute channel type is not set since the channel on the
1823 * tracing registry side does not have this information.
1824 */
1825
1826 ua_chan->enabled = uchan->enabled;
1827 ua_chan->tracing_channel_id = uchan->id;
1828
1829 DBG3("UST app shadow copy of channel %s done", ua_chan->name);
1830 }
1831
1832 /*
1833 * Copy data between a UST app session and a regular LTT session.
1834 */
1835 static void shadow_copy_session(struct ust_app_session *ua_sess,
1836 struct ltt_ust_session *usess, struct ust_app *app)
1837 {
1838 struct tm *timeinfo;
1839 char datetime[16];
1840 int ret;
1841 char tmp_shm_path[PATH_MAX];
1842
1843 timeinfo = localtime(&app->registration_time);
1844 strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
1845
1846 DBG2("Shadow copy of session handle %d", ua_sess->handle);
1847
1848 ua_sess->tracing_id = usess->id;
1849 ua_sess->id = get_next_session_id();
1850 LTTNG_OPTIONAL_SET(&ua_sess->real_credentials.uid, app->uid);
1851 LTTNG_OPTIONAL_SET(&ua_sess->real_credentials.gid, app->gid);
1852 LTTNG_OPTIONAL_SET(&ua_sess->effective_credentials.uid, usess->uid);
1853 LTTNG_OPTIONAL_SET(&ua_sess->effective_credentials.gid, usess->gid);
1854 ua_sess->buffer_type = usess->buffer_type;
1855 ua_sess->bits_per_long = app->bits_per_long;
1856
1857 /* There is only one consumer object per session possible. */
1858 consumer_output_get(usess->consumer);
1859 ua_sess->consumer = usess->consumer;
1860
1861 ua_sess->output_traces = usess->output_traces;
1862 ua_sess->live_timer_interval = usess->live_timer_interval;
1863 copy_channel_attr_to_ustctl(&ua_sess->metadata_attr,
1864 &usess->metadata_attr);
1865
1866 switch (ua_sess->buffer_type) {
1867 case LTTNG_BUFFER_PER_PID:
1868 ret = snprintf(ua_sess->path, sizeof(ua_sess->path),
1869 DEFAULT_UST_TRACE_PID_PATH "/%s-%d-%s", app->name, app->pid,
1870 datetime);
1871 break;
1872 case LTTNG_BUFFER_PER_UID:
1873 ret = snprintf(ua_sess->path, sizeof(ua_sess->path),
1874 DEFAULT_UST_TRACE_UID_PATH,
1875 lttng_credentials_get_uid(&ua_sess->real_credentials),
1876 app->bits_per_long);
1877 break;
1878 default:
1879 assert(0);
1880 goto error;
1881 }
1882 if (ret < 0) {
1883 PERROR("asprintf UST shadow copy session");
1884 assert(0);
1885 goto error;
1886 }
1887
1888 strncpy(ua_sess->root_shm_path, usess->root_shm_path,
1889 sizeof(ua_sess->root_shm_path));
1890 ua_sess->root_shm_path[sizeof(ua_sess->root_shm_path) - 1] = '\0';
1891 strncpy(ua_sess->shm_path, usess->shm_path,
1892 sizeof(ua_sess->shm_path));
1893 ua_sess->shm_path[sizeof(ua_sess->shm_path) - 1] = '\0';
1894 if (ua_sess->shm_path[0]) {
1895 switch (ua_sess->buffer_type) {
1896 case LTTNG_BUFFER_PER_PID:
1897 ret = snprintf(tmp_shm_path, sizeof(tmp_shm_path),
1898 "/" DEFAULT_UST_TRACE_PID_PATH "/%s-%d-%s",
1899 app->name, app->pid, datetime);
1900 break;
1901 case LTTNG_BUFFER_PER_UID:
1902 ret = snprintf(tmp_shm_path, sizeof(tmp_shm_path),
1903 "/" DEFAULT_UST_TRACE_UID_PATH,
1904 app->uid, app->bits_per_long);
1905 break;
1906 default:
1907 assert(0);
1908 goto error;
1909 }
1910 if (ret < 0) {
1911 PERROR("sprintf UST shadow copy session");
1912 assert(0);
1913 goto error;
1914 }
1915 strncat(ua_sess->shm_path, tmp_shm_path,
1916 sizeof(ua_sess->shm_path) - strlen(ua_sess->shm_path) - 1);
1917 ua_sess->shm_path[sizeof(ua_sess->shm_path) - 1] = '\0';
1918 }
1919 return;
1920
1921 error:
1922 consumer_output_put(ua_sess->consumer);
1923 }
1924
1925 /*
1926 * Lookup sesison wrapper.
1927 */
1928 static
1929 void __lookup_session_by_app(const struct ltt_ust_session *usess,
1930 struct ust_app *app, struct lttng_ht_iter *iter)
1931 {
1932 /* Get right UST app session from app */
1933 lttng_ht_lookup(app->sessions, &usess->id, iter);
1934 }
1935
1936 /*
1937 * Return ust app session from the app session hashtable using the UST session
1938 * id.
1939 */
1940 static struct ust_app_session *lookup_session_by_app(
1941 const struct ltt_ust_session *usess, struct ust_app *app)
1942 {
1943 struct lttng_ht_iter iter;
1944 struct lttng_ht_node_u64 *node;
1945
1946 __lookup_session_by_app(usess, app, &iter);
1947 node = lttng_ht_iter_get_node_u64(&iter);
1948 if (node == NULL) {
1949 goto error;
1950 }
1951
1952 return caa_container_of(node, struct ust_app_session, node);
1953
1954 error:
1955 return NULL;
1956 }
1957
1958 /*
1959 * Setup buffer registry per PID for the given session and application. If none
1960 * is found, a new one is created, added to the global registry and
1961 * initialized. If regp is valid, it's set with the newly created object.
1962 *
1963 * Return 0 on success or else a negative value.
1964 */
1965 static int setup_buffer_reg_pid(struct ust_app_session *ua_sess,
1966 struct ust_app *app, struct buffer_reg_pid **regp)
1967 {
1968 int ret = 0;
1969 struct buffer_reg_pid *reg_pid;
1970
1971 assert(ua_sess);
1972 assert(app);
1973
1974 rcu_read_lock();
1975
1976 reg_pid = buffer_reg_pid_find(ua_sess->id);
1977 if (!reg_pid) {
1978 /*
1979 * This is the create channel path meaning that if there is NO
1980 * registry available, we have to create one for this session.
1981 */
1982 ret = buffer_reg_pid_create(ua_sess->id, &reg_pid,
1983 ua_sess->root_shm_path, ua_sess->shm_path);
1984 if (ret < 0) {
1985 goto error;
1986 }
1987 } else {
1988 goto end;
1989 }
1990
1991 /* Initialize registry. */
1992 ret = ust_registry_session_init(&reg_pid->registry->reg.ust, app,
1993 app->bits_per_long, app->uint8_t_alignment,
1994 app->uint16_t_alignment, app->uint32_t_alignment,
1995 app->uint64_t_alignment, app->long_alignment,
1996 app->byte_order, app->version.major, app->version.minor,
1997 reg_pid->root_shm_path, reg_pid->shm_path,
1998 lttng_credentials_get_uid(&ua_sess->effective_credentials),
1999 lttng_credentials_get_gid(&ua_sess->effective_credentials),
2000 ua_sess->tracing_id,
2001 app->uid);
2002 if (ret < 0) {
2003 /*
2004 * reg_pid->registry->reg.ust is NULL upon error, so we need to
2005 * destroy the buffer registry, because it is always expected
2006 * that if the buffer registry can be found, its ust registry is
2007 * non-NULL.
2008 */
2009 buffer_reg_pid_destroy(reg_pid);
2010 goto error;
2011 }
2012
2013 buffer_reg_pid_add(reg_pid);
2014
2015 DBG3("UST app buffer registry per PID created successfully");
2016
2017 end:
2018 if (regp) {
2019 *regp = reg_pid;
2020 }
2021 error:
2022 rcu_read_unlock();
2023 return ret;
2024 }
2025
2026 /*
2027 * Setup buffer registry per UID for the given session and application. If none
2028 * is found, a new one is created, added to the global registry and
2029 * initialized. If regp is valid, it's set with the newly created object.
2030 *
2031 * Return 0 on success or else a negative value.
2032 */
2033 static int setup_buffer_reg_uid(struct ltt_ust_session *usess,
2034 struct ust_app_session *ua_sess,
2035 struct ust_app *app, struct buffer_reg_uid **regp)
2036 {
2037 int ret = 0;
2038 struct buffer_reg_uid *reg_uid;
2039
2040 assert(usess);
2041 assert(app);
2042
2043 rcu_read_lock();
2044
2045 reg_uid = buffer_reg_uid_find(usess->id, app->bits_per_long, app->uid);
2046 if (!reg_uid) {
2047 /*
2048 * This is the create channel path meaning that if there is NO
2049 * registry available, we have to create one for this session.
2050 */
2051 ret = buffer_reg_uid_create(usess->id, app->bits_per_long, app->uid,
2052 LTTNG_DOMAIN_UST, &reg_uid,
2053 ua_sess->root_shm_path, ua_sess->shm_path);
2054 if (ret < 0) {
2055 goto error;
2056 }
2057 } else {
2058 goto end;
2059 }
2060
2061 /* Initialize registry. */
2062 ret = ust_registry_session_init(&reg_uid->registry->reg.ust, NULL,
2063 app->bits_per_long, app->uint8_t_alignment,
2064 app->uint16_t_alignment, app->uint32_t_alignment,
2065 app->uint64_t_alignment, app->long_alignment,
2066 app->byte_order, app->version.major,
2067 app->version.minor, reg_uid->root_shm_path,
2068 reg_uid->shm_path, usess->uid, usess->gid,
2069 ua_sess->tracing_id, app->uid);
2070 if (ret < 0) {
2071 /*
2072 * reg_uid->registry->reg.ust is NULL upon error, so we need to
2073 * destroy the buffer registry, because it is always expected
2074 * that if the buffer registry can be found, its ust registry is
2075 * non-NULL.
2076 */
2077 buffer_reg_uid_destroy(reg_uid, NULL);
2078 goto error;
2079 }
2080 /* Add node to teardown list of the session. */
2081 cds_list_add(&reg_uid->lnode, &usess->buffer_reg_uid_list);
2082
2083 buffer_reg_uid_add(reg_uid);
2084
2085 DBG3("UST app buffer registry per UID created successfully");
2086 end:
2087 if (regp) {
2088 *regp = reg_uid;
2089 }
2090 error:
2091 rcu_read_unlock();
2092 return ret;
2093 }
2094
2095 /*
2096 * Create a session on the tracer side for the given app.
2097 *
2098 * On success, ua_sess_ptr is populated with the session pointer or else left
2099 * untouched. If the session was created, is_created is set to 1. On error,
2100 * it's left untouched. Note that ua_sess_ptr is mandatory but is_created can
2101 * be NULL.
2102 *
2103 * Returns 0 on success or else a negative code which is either -ENOMEM or
2104 * -ENOTCONN which is the default code if the ustctl_create_session fails.
2105 */
2106 static int find_or_create_ust_app_session(struct ltt_ust_session *usess,
2107 struct ust_app *app, struct ust_app_session **ua_sess_ptr,
2108 int *is_created)
2109 {
2110 int ret, created = 0;
2111 struct ust_app_session *ua_sess;
2112
2113 assert(usess);
2114 assert(app);
2115 assert(ua_sess_ptr);
2116
2117 health_code_update();
2118
2119 ua_sess = lookup_session_by_app(usess, app);
2120 if (ua_sess == NULL) {
2121 DBG2("UST app pid: %d session id %" PRIu64 " not found, creating it",
2122 app->pid, usess->id);
2123 ua_sess = alloc_ust_app_session();
2124 if (ua_sess == NULL) {
2125 /* Only malloc can failed so something is really wrong */
2126 ret = -ENOMEM;
2127 goto error;
2128 }
2129 shadow_copy_session(ua_sess, usess, app);
2130 created = 1;
2131 }
2132
2133 switch (usess->buffer_type) {
2134 case LTTNG_BUFFER_PER_PID:
2135 /* Init local registry. */
2136 ret = setup_buffer_reg_pid(ua_sess, app, NULL);
2137 if (ret < 0) {
2138 delete_ust_app_session(-1, ua_sess, app);
2139 goto error;
2140 }
2141 break;
2142 case LTTNG_BUFFER_PER_UID:
2143 /* Look for a global registry. If none exists, create one. */
2144 ret = setup_buffer_reg_uid(usess, ua_sess, app, NULL);
2145 if (ret < 0) {
2146 delete_ust_app_session(-1, ua_sess, app);
2147 goto error;
2148 }
2149 break;
2150 default:
2151 assert(0);
2152 ret = -EINVAL;
2153 goto error;
2154 }
2155
2156 health_code_update();
2157
2158 if (ua_sess->handle == -1) {
2159 pthread_mutex_lock(&app->sock_lock);
2160 ret = ustctl_create_session(app->sock);
2161 pthread_mutex_unlock(&app->sock_lock);
2162 if (ret < 0) {
2163 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
2164 ERR("Creating session for app pid %d with ret %d",
2165 app->pid, ret);
2166 } else {
2167 DBG("UST app creating session failed. Application is dead");
2168 /*
2169 * This is normal behavior, an application can die during the
2170 * creation process. Don't report an error so the execution can
2171 * continue normally. This will get flagged ENOTCONN and the
2172 * caller will handle it.
2173 */
2174 ret = 0;
2175 }
2176 delete_ust_app_session(-1, ua_sess, app);
2177 if (ret != -ENOMEM) {
2178 /*
2179 * Tracer is probably gone or got an internal error so let's
2180 * behave like it will soon unregister or not usable.
2181 */
2182 ret = -ENOTCONN;
2183 }
2184 goto error;
2185 }
2186
2187 ua_sess->handle = ret;
2188
2189 /* Add ust app session to app's HT */
2190 lttng_ht_node_init_u64(&ua_sess->node,
2191 ua_sess->tracing_id);
2192 lttng_ht_add_unique_u64(app->sessions, &ua_sess->node);
2193 lttng_ht_node_init_ulong(&ua_sess->ust_objd_node, ua_sess->handle);
2194 lttng_ht_add_unique_ulong(app->ust_sessions_objd,
2195 &ua_sess->ust_objd_node);
2196
2197 DBG2("UST app session created successfully with handle %d", ret);
2198 }
2199
2200 *ua_sess_ptr = ua_sess;
2201 if (is_created) {
2202 *is_created = created;
2203 }
2204
2205 /* Everything went well. */
2206 ret = 0;
2207
2208 error:
2209 health_code_update();
2210 return ret;
2211 }
2212
2213 /*
2214 * Match function for a hash table lookup of ust_app_ctx.
2215 *
2216 * It matches an ust app context based on the context type and, in the case
2217 * of perf counters, their name.
2218 */
2219 static int ht_match_ust_app_ctx(struct cds_lfht_node *node, const void *_key)
2220 {
2221 struct ust_app_ctx *ctx;
2222 const struct lttng_ust_context_attr *key;
2223
2224 assert(node);
2225 assert(_key);
2226
2227 ctx = caa_container_of(node, struct ust_app_ctx, node.node);
2228 key = _key;
2229
2230 /* Context type */
2231 if (ctx->ctx.ctx != key->ctx) {
2232 goto no_match;
2233 }
2234
2235 switch(key->ctx) {
2236 case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
2237 if (strncmp(key->u.perf_counter.name,
2238 ctx->ctx.u.perf_counter.name,
2239 sizeof(key->u.perf_counter.name))) {
2240 goto no_match;
2241 }
2242 break;
2243 case LTTNG_UST_CONTEXT_APP_CONTEXT:
2244 if (strcmp(key->u.app_ctx.provider_name,
2245 ctx->ctx.u.app_ctx.provider_name) ||
2246 strcmp(key->u.app_ctx.ctx_name,
2247 ctx->ctx.u.app_ctx.ctx_name)) {
2248 goto no_match;
2249 }
2250 break;
2251 default:
2252 break;
2253 }
2254
2255 /* Match. */
2256 return 1;
2257
2258 no_match:
2259 return 0;
2260 }
2261
2262 /*
2263 * Lookup for an ust app context from an lttng_ust_context.
2264 *
2265 * Must be called while holding RCU read side lock.
2266 * Return an ust_app_ctx object or NULL on error.
2267 */
2268 static
2269 struct ust_app_ctx *find_ust_app_context(struct lttng_ht *ht,
2270 struct lttng_ust_context_attr *uctx)
2271 {
2272 struct lttng_ht_iter iter;
2273 struct lttng_ht_node_ulong *node;
2274 struct ust_app_ctx *app_ctx = NULL;
2275
2276 assert(uctx);
2277 assert(ht);
2278
2279 /* Lookup using the lttng_ust_context_type and a custom match fct. */
2280 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) uctx->ctx, lttng_ht_seed),
2281 ht_match_ust_app_ctx, uctx, &iter.iter);
2282 node = lttng_ht_iter_get_node_ulong(&iter);
2283 if (!node) {
2284 goto end;
2285 }
2286
2287 app_ctx = caa_container_of(node, struct ust_app_ctx, node);
2288
2289 end:
2290 return app_ctx;
2291 }
2292
2293 /*
2294 * Create a context for the channel on the tracer.
2295 *
2296 * Called with UST app session lock held and a RCU read side lock.
2297 */
2298 static
2299 int create_ust_app_channel_context(struct ust_app_channel *ua_chan,
2300 struct lttng_ust_context_attr *uctx,
2301 struct ust_app *app)
2302 {
2303 int ret = 0;
2304 struct ust_app_ctx *ua_ctx;
2305
2306 DBG2("UST app adding context to channel %s", ua_chan->name);
2307
2308 ua_ctx = find_ust_app_context(ua_chan->ctx, uctx);
2309 if (ua_ctx) {
2310 ret = -EEXIST;
2311 goto error;
2312 }
2313
2314 ua_ctx = alloc_ust_app_ctx(uctx);
2315 if (ua_ctx == NULL) {
2316 /* malloc failed */
2317 ret = -ENOMEM;
2318 goto error;
2319 }
2320
2321 lttng_ht_node_init_ulong(&ua_ctx->node, (unsigned long) ua_ctx->ctx.ctx);
2322 lttng_ht_add_ulong(ua_chan->ctx, &ua_ctx->node);
2323 cds_list_add_tail(&ua_ctx->list, &ua_chan->ctx_list);
2324
2325 ret = create_ust_channel_context(ua_chan, ua_ctx, app);
2326 if (ret < 0) {
2327 goto error;
2328 }
2329
2330 error:
2331 return ret;
2332 }
2333
2334 /*
2335 * Enable on the tracer side a ust app event for the session and channel.
2336 *
2337 * Called with UST app session lock held.
2338 */
2339 static
2340 int enable_ust_app_event(struct ust_app_session *ua_sess,
2341 struct ust_app_event *ua_event, struct ust_app *app)
2342 {
2343 int ret;
2344
2345 ret = enable_ust_event(app, ua_sess, ua_event);
2346 if (ret < 0) {
2347 goto error;
2348 }
2349
2350 ua_event->enabled = 1;
2351
2352 error:
2353 return ret;
2354 }
2355
2356 /*
2357 * Disable on the tracer side a ust app event for the session and channel.
2358 */
2359 static int disable_ust_app_event(struct ust_app_session *ua_sess,
2360 struct ust_app_event *ua_event, struct ust_app *app)
2361 {
2362 int ret;
2363
2364 ret = disable_ust_event(app, ua_sess, ua_event);
2365 if (ret < 0) {
2366 goto error;
2367 }
2368
2369 ua_event->enabled = 0;
2370
2371 error:
2372 return ret;
2373 }
2374
2375 /*
2376 * Lookup ust app channel for session and disable it on the tracer side.
2377 */
2378 static
2379 int disable_ust_app_channel(struct ust_app_session *ua_sess,
2380 struct ust_app_channel *ua_chan, struct ust_app *app)
2381 {
2382 int ret;
2383
2384 ret = disable_ust_channel(app, ua_sess, ua_chan);
2385 if (ret < 0) {
2386 goto error;
2387 }
2388
2389 ua_chan->enabled = 0;
2390
2391 error:
2392 return ret;
2393 }
2394
2395 /*
2396 * Lookup ust app channel for session and enable it on the tracer side. This
2397 * MUST be called with a RCU read side lock acquired.
2398 */
2399 static int enable_ust_app_channel(struct ust_app_session *ua_sess,
2400 struct ltt_ust_channel *uchan, struct ust_app *app)
2401 {
2402 int ret = 0;
2403 struct lttng_ht_iter iter;
2404 struct lttng_ht_node_str *ua_chan_node;
2405 struct ust_app_channel *ua_chan;
2406
2407 lttng_ht_lookup(ua_sess->channels, (void *)uchan->name, &iter);
2408 ua_chan_node = lttng_ht_iter_get_node_str(&iter);
2409 if (ua_chan_node == NULL) {
2410 DBG2("Unable to find channel %s in ust session id %" PRIu64,
2411 uchan->name, ua_sess->tracing_id);
2412 goto error;
2413 }
2414
2415 ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
2416
2417 ret = enable_ust_channel(app, ua_sess, ua_chan);
2418 if (ret < 0) {
2419 goto error;
2420 }
2421
2422 error:
2423 return ret;
2424 }
2425
2426 /*
2427 * Ask the consumer to create a channel and get it if successful.
2428 *
2429 * Called with UST app session lock held.
2430 *
2431 * Return 0 on success or else a negative value.
2432 */
2433 static int do_consumer_create_channel(struct ltt_ust_session *usess,
2434 struct ust_app_session *ua_sess, struct ust_app_channel *ua_chan,
2435 int bitness, struct ust_registry_session *registry,
2436 uint64_t trace_archive_id)
2437 {
2438 int ret;
2439 unsigned int nb_fd = 0;
2440 struct consumer_socket *socket;
2441
2442 assert(usess);
2443 assert(ua_sess);
2444 assert(ua_chan);
2445 assert(registry);
2446
2447 rcu_read_lock();
2448 health_code_update();
2449
2450 /* Get the right consumer socket for the application. */
2451 socket = consumer_find_socket_by_bitness(bitness, usess->consumer);
2452 if (!socket) {
2453 ret = -EINVAL;
2454 goto error;
2455 }
2456
2457 health_code_update();
2458
2459 /* Need one fd for the channel. */
2460 ret = lttng_fd_get(LTTNG_FD_APPS, 1);
2461 if (ret < 0) {
2462 ERR("Exhausted number of available FD upon create channel");
2463 goto error;
2464 }
2465
2466 /*
2467 * Ask consumer to create channel. The consumer will return the number of
2468 * stream we have to expect.
2469 */
2470 ret = ust_consumer_ask_channel(ua_sess, ua_chan, usess->consumer, socket,
2471 registry, usess->current_trace_chunk);
2472 if (ret < 0) {
2473 goto error_ask;
2474 }
2475
2476 /*
2477 * Compute the number of fd needed before receiving them. It must be 2 per
2478 * stream (2 being the default value here).
2479 */
2480 nb_fd = DEFAULT_UST_STREAM_FD_NUM * ua_chan->expected_stream_count;
2481
2482 /* Reserve the amount of file descriptor we need. */
2483 ret = lttng_fd_get(LTTNG_FD_APPS, nb_fd);
2484 if (ret < 0) {
2485 ERR("Exhausted number of available FD upon create channel");
2486 goto error_fd_get_stream;
2487 }
2488
2489 health_code_update();
2490
2491 /*
2492 * Now get the channel from the consumer. This call wil populate the stream
2493 * list of that channel and set the ust objects.
2494 */
2495 if (usess->consumer->enabled) {
2496 ret = ust_consumer_get_channel(socket, ua_chan);
2497 if (ret < 0) {
2498 goto error_destroy;
2499 }
2500 }
2501
2502 rcu_read_unlock();
2503 return 0;
2504
2505 error_destroy:
2506 lttng_fd_put(LTTNG_FD_APPS, nb_fd);
2507 error_fd_get_stream:
2508 /*
2509 * Initiate a destroy channel on the consumer since we had an error
2510 * handling it on our side. The return value is of no importance since we
2511 * already have a ret value set by the previous error that we need to
2512 * return.
2513 */
2514 (void) ust_consumer_destroy_channel(socket, ua_chan);
2515 error_ask:
2516 lttng_fd_put(LTTNG_FD_APPS, 1);
2517 error:
2518 health_code_update();
2519 rcu_read_unlock();
2520 return ret;
2521 }
2522
2523 /*
2524 * Duplicate the ust data object of the ust app stream and save it in the
2525 * buffer registry stream.
2526 *
2527 * Return 0 on success or else a negative value.
2528 */
2529 static int duplicate_stream_object(struct buffer_reg_stream *reg_stream,
2530 struct ust_app_stream *stream)
2531 {
2532 int ret;
2533
2534 assert(reg_stream);
2535 assert(stream);
2536
2537 /* Reserve the amount of file descriptor we need. */
2538 ret = lttng_fd_get(LTTNG_FD_APPS, 2);
2539 if (ret < 0) {
2540 ERR("Exhausted number of available FD upon duplicate stream");
2541 goto error;
2542 }
2543
2544 /* Duplicate object for stream once the original is in the registry. */
2545 ret = ustctl_duplicate_ust_object_data(&stream->obj,
2546 reg_stream->obj.ust);
2547 if (ret < 0) {
2548 ERR("Duplicate stream obj from %p to %p failed with ret %d",
2549 reg_stream->obj.ust, stream->obj, ret);
2550 lttng_fd_put(LTTNG_FD_APPS, 2);
2551 goto error;
2552 }
2553 stream->handle = stream->obj->handle;
2554
2555 error:
2556 return ret;
2557 }
2558
2559 /*
2560 * Duplicate the ust data object of the ust app. channel and save it in the
2561 * buffer registry channel.
2562 *
2563 * Return 0 on success or else a negative value.
2564 */
2565 static int duplicate_channel_object(struct buffer_reg_channel *reg_chan,
2566 struct ust_app_channel *ua_chan)
2567 {
2568 int ret;
2569
2570 assert(reg_chan);
2571 assert(ua_chan);
2572
2573 /* Need two fds for the channel. */
2574 ret = lttng_fd_get(LTTNG_FD_APPS, 1);
2575 if (ret < 0) {
2576 ERR("Exhausted number of available FD upon duplicate channel");
2577 goto error_fd_get;
2578 }
2579
2580 /* Duplicate object for stream once the original is in the registry. */
2581 ret = ustctl_duplicate_ust_object_data(&ua_chan->obj, reg_chan->obj.ust);
2582 if (ret < 0) {
2583 ERR("Duplicate channel obj from %p to %p failed with ret: %d",
2584 reg_chan->obj.ust, ua_chan->obj, ret);
2585 goto error;
2586 }
2587 ua_chan->handle = ua_chan->obj->handle;
2588
2589 return 0;
2590
2591 error:
2592 lttng_fd_put(LTTNG_FD_APPS, 1);
2593 error_fd_get:
2594 return ret;
2595 }
2596
2597 /*
2598 * For a given channel buffer registry, setup all streams of the given ust
2599 * application channel.
2600 *
2601 * Return 0 on success or else a negative value.
2602 */
2603 static int setup_buffer_reg_streams(struct buffer_reg_channel *reg_chan,
2604 struct ust_app_channel *ua_chan,
2605 struct ust_app *app)
2606 {
2607 int ret = 0;
2608 struct ust_app_stream *stream, *stmp;
2609
2610 assert(reg_chan);
2611 assert(ua_chan);
2612
2613 DBG2("UST app setup buffer registry stream");
2614
2615 /* Send all streams to application. */
2616 cds_list_for_each_entry_safe(stream, stmp, &ua_chan->streams.head, list) {
2617 struct buffer_reg_stream *reg_stream;
2618
2619 ret = buffer_reg_stream_create(&reg_stream);
2620 if (ret < 0) {
2621 goto error;
2622 }
2623
2624 /*
2625 * Keep original pointer and nullify it in the stream so the delete
2626 * stream call does not release the object.
2627 */
2628 reg_stream->obj.ust = stream->obj;
2629 stream->obj = NULL;
2630 buffer_reg_stream_add(reg_stream, reg_chan);
2631
2632 /* We don't need the streams anymore. */
2633 cds_list_del(&stream->list);
2634 delete_ust_app_stream(-1, stream, app);
2635 }
2636
2637 error:
2638 return ret;
2639 }
2640
2641 /*
2642 * Create a buffer registry channel for the given session registry and
2643 * application channel object. If regp pointer is valid, it's set with the
2644 * created object. Important, the created object is NOT added to the session
2645 * registry hash table.
2646 *
2647 * Return 0 on success else a negative value.
2648 */
2649 static int create_buffer_reg_channel(struct buffer_reg_session *reg_sess,
2650 struct ust_app_channel *ua_chan, struct buffer_reg_channel **regp)
2651 {
2652 int ret;
2653 struct buffer_reg_channel *reg_chan = NULL;
2654
2655 assert(reg_sess);
2656 assert(ua_chan);
2657
2658 DBG2("UST app creating buffer registry channel for %s", ua_chan->name);
2659
2660 /* Create buffer registry channel. */
2661 ret = buffer_reg_channel_create(ua_chan->tracing_channel_id, &reg_chan);
2662 if (ret < 0) {
2663 goto error_create;
2664 }
2665 assert(reg_chan);
2666 reg_chan->consumer_key = ua_chan->key;
2667 reg_chan->subbuf_size = ua_chan->attr.subbuf_size;
2668 reg_chan->num_subbuf = ua_chan->attr.num_subbuf;
2669
2670 /* Create and add a channel registry to session. */
2671 ret = ust_registry_channel_add(reg_sess->reg.ust,
2672 ua_chan->tracing_channel_id);
2673 if (ret < 0) {
2674 goto error;
2675 }
2676 buffer_reg_channel_add(reg_sess, reg_chan);
2677
2678 if (regp) {
2679 *regp = reg_chan;
2680 }
2681
2682 return 0;
2683
2684 error:
2685 /* Safe because the registry channel object was not added to any HT. */
2686 buffer_reg_channel_destroy(reg_chan, LTTNG_DOMAIN_UST);
2687 error_create:
2688 return ret;
2689 }
2690
2691 /*
2692 * Setup buffer registry channel for the given session registry and application
2693 * channel object. If regp pointer is valid, it's set with the created object.
2694 *
2695 * Return 0 on success else a negative value.
2696 */
2697 static int setup_buffer_reg_channel(struct buffer_reg_session *reg_sess,
2698 struct ust_app_channel *ua_chan, struct buffer_reg_channel *reg_chan,
2699 struct ust_app *app)
2700 {
2701 int ret;
2702
2703 assert(reg_sess);
2704 assert(reg_chan);
2705 assert(ua_chan);
2706 assert(ua_chan->obj);
2707
2708 DBG2("UST app setup buffer registry channel for %s", ua_chan->name);
2709
2710 /* Setup all streams for the registry. */
2711 ret = setup_buffer_reg_streams(reg_chan, ua_chan, app);
2712 if (ret < 0) {
2713 goto error;
2714 }
2715
2716 reg_chan->obj.ust = ua_chan->obj;
2717 ua_chan->obj = NULL;
2718
2719 return 0;
2720
2721 error:
2722 buffer_reg_channel_remove(reg_sess, reg_chan);
2723 buffer_reg_channel_destroy(reg_chan, LTTNG_DOMAIN_UST);
2724 return ret;
2725 }
2726
2727 /*
2728 * Send buffer registry channel to the application.
2729 *
2730 * Return 0 on success else a negative value.
2731 */
2732 static int send_channel_uid_to_ust(struct buffer_reg_channel *reg_chan,
2733 struct ust_app *app, struct ust_app_session *ua_sess,
2734 struct ust_app_channel *ua_chan)
2735 {
2736 int ret;
2737 struct buffer_reg_stream *reg_stream;
2738
2739 assert(reg_chan);
2740 assert(app);
2741 assert(ua_sess);
2742 assert(ua_chan);
2743
2744 DBG("UST app sending buffer registry channel to ust sock %d", app->sock);
2745
2746 ret = duplicate_channel_object(reg_chan, ua_chan);
2747 if (ret < 0) {
2748 goto error;
2749 }
2750
2751 /* Send channel to the application. */
2752 ret = ust_consumer_send_channel_to_ust(app, ua_sess, ua_chan);
2753 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
2754 ret = -ENOTCONN; /* Caused by app exiting. */
2755 goto error;
2756 } else if (ret < 0) {
2757 goto error;
2758 }
2759
2760 health_code_update();
2761
2762 /* Send all streams to application. */
2763 pthread_mutex_lock(&reg_chan->stream_list_lock);
2764 cds_list_for_each_entry(reg_stream, &reg_chan->streams, lnode) {
2765 struct ust_app_stream stream;
2766
2767 ret = duplicate_stream_object(reg_stream, &stream);
2768 if (ret < 0) {
2769 goto error_stream_unlock;
2770 }
2771
2772 ret = ust_consumer_send_stream_to_ust(app, ua_chan, &stream);
2773 if (ret < 0) {
2774 (void) release_ust_app_stream(-1, &stream, app);
2775 if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
2776 ret = -ENOTCONN; /* Caused by app exiting. */
2777 }
2778 goto error_stream_unlock;
2779 }
2780
2781 /*
2782 * The return value is not important here. This function will output an
2783 * error if needed.
2784 */
2785 (void) release_ust_app_stream(-1, &stream, app);
2786 }
2787 ua_chan->is_sent = 1;
2788
2789 error_stream_unlock:
2790 pthread_mutex_unlock(&reg_chan->stream_list_lock);
2791 error:
2792 return ret;
2793 }
2794
2795 /*
2796 * Create and send to the application the created buffers with per UID buffers.
2797 *
2798 * This MUST be called with a RCU read side lock acquired.
2799 * The session list lock and the session's lock must be acquired.
2800 *
2801 * Return 0 on success else a negative value.
2802 */
2803 static int create_channel_per_uid(struct ust_app *app,
2804 struct ltt_ust_session *usess, struct ust_app_session *ua_sess,
2805 struct ust_app_channel *ua_chan)
2806 {
2807 int ret;
2808 struct buffer_reg_uid *reg_uid;
2809 struct buffer_reg_channel *reg_chan;
2810 struct ltt_session *session = NULL;
2811 enum lttng_error_code notification_ret;
2812 struct ust_registry_channel *chan_reg;
2813
2814 assert(app);
2815 assert(usess);
2816 assert(ua_sess);
2817 assert(ua_chan);
2818
2819 DBG("UST app creating channel %s with per UID buffers", ua_chan->name);
2820
2821 reg_uid = buffer_reg_uid_find(usess->id, app->bits_per_long, app->uid);
2822 /*
2823 * The session creation handles the creation of this global registry
2824 * object. If none can be find, there is a code flow problem or a
2825 * teardown race.
2826 */
2827 assert(reg_uid);
2828
2829 reg_chan = buffer_reg_channel_find(ua_chan->tracing_channel_id,
2830 reg_uid);
2831 if (reg_chan) {
2832 goto send_channel;
2833 }
2834
2835 /* Create the buffer registry channel object. */
2836 ret = create_buffer_reg_channel(reg_uid->registry, ua_chan, &reg_chan);
2837 if (ret < 0) {
2838 ERR("Error creating the UST channel \"%s\" registry instance",
2839 ua_chan->name);
2840 goto error;
2841 }
2842
2843 session = session_find_by_id(ua_sess->tracing_id);
2844 assert(session);
2845 assert(pthread_mutex_trylock(&session->lock));
2846 assert(session_trylock_list());
2847
2848 /*
2849 * Create the buffers on the consumer side. This call populates the
2850 * ust app channel object with all streams and data object.
2851 */
2852 ret = do_consumer_create_channel(usess, ua_sess, ua_chan,
2853 app->bits_per_long, reg_uid->registry->reg.ust,
2854 session->most_recent_chunk_id.value);
2855 if (ret < 0) {
2856 ERR("Error creating UST channel \"%s\" on the consumer daemon",
2857 ua_chan->name);
2858
2859 /*
2860 * Let's remove the previously created buffer registry channel so
2861 * it's not visible anymore in the session registry.
2862 */
2863 ust_registry_channel_del_free(reg_uid->registry->reg.ust,
2864 ua_chan->tracing_channel_id, false);
2865 buffer_reg_channel_remove(reg_uid->registry, reg_chan);
2866 buffer_reg_channel_destroy(reg_chan, LTTNG_DOMAIN_UST);
2867 goto error;
2868 }
2869
2870 /*
2871 * Setup the streams and add it to the session registry.
2872 */
2873 ret = setup_buffer_reg_channel(reg_uid->registry,
2874 ua_chan, reg_chan, app);
2875 if (ret < 0) {
2876 ERR("Error setting up UST channel \"%s\"", ua_chan->name);
2877 goto error;
2878 }
2879
2880 /* Notify the notification subsystem of the channel's creation. */
2881 pthread_mutex_lock(&reg_uid->registry->reg.ust->lock);
2882 chan_reg = ust_registry_channel_find(reg_uid->registry->reg.ust,
2883 ua_chan->tracing_channel_id);
2884 assert(chan_reg);
2885 chan_reg->consumer_key = ua_chan->key;
2886 chan_reg = NULL;
2887 pthread_mutex_unlock(&reg_uid->registry->reg.ust->lock);
2888
2889 notification_ret = notification_thread_command_add_channel(
2890 notification_thread_handle, session->name,
2891 lttng_credentials_get_uid(&ua_sess->effective_credentials),
2892 lttng_credentials_get_gid(&ua_sess->effective_credentials),
2893 ua_chan->name,
2894 ua_chan->key, LTTNG_DOMAIN_UST,
2895 ua_chan->attr.subbuf_size * ua_chan->attr.num_subbuf);
2896 if (notification_ret != LTTNG_OK) {
2897 ret = - (int) notification_ret;
2898 ERR("Failed to add channel to notification thread");
2899 goto error;
2900 }
2901
2902 send_channel:
2903 /* Send buffers to the application. */
2904 ret = send_channel_uid_to_ust(reg_chan, app, ua_sess, ua_chan);
2905 if (ret < 0) {
2906 if (ret != -ENOTCONN) {
2907 ERR("Error sending channel to application");
2908 }
2909 goto error;
2910 }
2911
2912 error:
2913 if (session) {
2914 session_put(session);
2915 }
2916 return ret;
2917 }
2918
2919 /*
2920 * Create and send to the application the created buffers with per PID buffers.
2921 *
2922 * Called with UST app session lock held.
2923 * The session list lock and the session's lock must be acquired.
2924 *
2925 * Return 0 on success else a negative value.
2926 */
2927 static int create_channel_per_pid(struct ust_app *app,
2928 struct ltt_ust_session *usess, struct ust_app_session *ua_sess,
2929 struct ust_app_channel *ua_chan)
2930 {
2931 int ret;
2932 struct ust_registry_session *registry;
2933 enum lttng_error_code cmd_ret;
2934 struct ltt_session *session = NULL;
2935 uint64_t chan_reg_key;
2936 struct ust_registry_channel *chan_reg;
2937
2938 assert(app);
2939 assert(usess);
2940 assert(ua_sess);
2941 assert(ua_chan);
2942
2943 DBG("UST app creating channel %s with per PID buffers", ua_chan->name);
2944
2945 rcu_read_lock();
2946
2947 registry = get_session_registry(ua_sess);
2948 /* The UST app session lock is held, registry shall not be null. */
2949 assert(registry);
2950
2951 /* Create and add a new channel registry to session. */
2952 ret = ust_registry_channel_add(registry, ua_chan->key);
2953 if (ret < 0) {
2954 ERR("Error creating the UST channel \"%s\" registry instance",
2955 ua_chan->name);
2956 goto error;
2957 }
2958
2959 session = session_find_by_id(ua_sess->tracing_id);
2960 assert(session);
2961
2962 assert(pthread_mutex_trylock(&session->lock));
2963 assert(session_trylock_list());
2964
2965 /* Create and get channel on the consumer side. */
2966 ret = do_consumer_create_channel(usess, ua_sess, ua_chan,
2967 app->bits_per_long, registry,
2968 session->most_recent_chunk_id.value);
2969 if (ret < 0) {
2970 ERR("Error creating UST channel \"%s\" on the consumer daemon",
2971 ua_chan->name);
2972 goto error_remove_from_registry;
2973 }
2974
2975 ret = send_channel_pid_to_ust(app, ua_sess, ua_chan);
2976 if (ret < 0) {
2977 if (ret != -ENOTCONN) {
2978 ERR("Error sending channel to application");
2979 }
2980 goto error_remove_from_registry;
2981 }
2982
2983 chan_reg_key = ua_chan->key;
2984 pthread_mutex_lock(&registry->lock);
2985 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
2986 assert(chan_reg);
2987 chan_reg->consumer_key = ua_chan->key;
2988 pthread_mutex_unlock(&registry->lock);
2989
2990 cmd_ret = notification_thread_command_add_channel(
2991 notification_thread_handle, session->name,
2992 lttng_credentials_get_uid(&ua_sess->effective_credentials),
2993 lttng_credentials_get_gid(&ua_sess->effective_credentials),
2994 ua_chan->name,
2995 ua_chan->key, LTTNG_DOMAIN_UST,
2996 ua_chan->attr.subbuf_size * ua_chan->attr.num_subbuf);
2997 if (cmd_ret != LTTNG_OK) {
2998 ret = - (int) cmd_ret;
2999 ERR("Failed to add channel to notification thread");
3000 goto error_remove_from_registry;
3001 }
3002
3003 error_remove_from_registry:
3004 if (ret) {
3005 ust_registry_channel_del_free(registry, ua_chan->key, false);
3006 }
3007 error:
3008 rcu_read_unlock();
3009 if (session) {
3010 session_put(session);
3011 }
3012 return ret;
3013 }
3014
3015 /*
3016 * From an already allocated ust app channel, create the channel buffers if
3017 * needed and send them to the application. This MUST be called with a RCU read
3018 * side lock acquired.
3019 *
3020 * Called with UST app session lock held.
3021 *
3022 * Return 0 on success or else a negative value. Returns -ENOTCONN if
3023 * the application exited concurrently.
3024 */
3025 static int ust_app_channel_send(struct ust_app *app,
3026 struct ltt_ust_session *usess, struct ust_app_session *ua_sess,
3027 struct ust_app_channel *ua_chan)
3028 {
3029 int ret;
3030
3031 assert(app);
3032 assert(usess);
3033 assert(usess->active);
3034 assert(ua_sess);
3035 assert(ua_chan);
3036
3037 /* Handle buffer type before sending the channel to the application. */
3038 switch (usess->buffer_type) {
3039 case LTTNG_BUFFER_PER_UID:
3040 {
3041 ret = create_channel_per_uid(app, usess, ua_sess, ua_chan);
3042 if (ret < 0) {
3043 goto error;
3044 }
3045 break;
3046 }
3047 case LTTNG_BUFFER_PER_PID:
3048 {
3049 ret = create_channel_per_pid(app, usess, ua_sess, ua_chan);
3050 if (ret < 0) {
3051 goto error;
3052 }
3053 break;
3054 }
3055 default:
3056 assert(0);
3057 ret = -EINVAL;
3058 goto error;
3059 }
3060
3061 /* Initialize ust objd object using the received handle and add it. */
3062 lttng_ht_node_init_ulong(&ua_chan->ust_objd_node, ua_chan->handle);
3063 lttng_ht_add_unique_ulong(app->ust_objd, &ua_chan->ust_objd_node);
3064
3065 /* If channel is not enabled, disable it on the tracer */
3066 if (!ua_chan->enabled) {
3067 ret = disable_ust_channel(app, ua_sess, ua_chan);
3068 if (ret < 0) {
3069 goto error;
3070 }
3071 }
3072
3073 error:
3074 return ret;
3075 }
3076
3077 /*
3078 * Create UST app channel and return it through ua_chanp if not NULL.
3079 *
3080 * Called with UST app session lock and RCU read-side lock held.
3081 *
3082 * Return 0 on success or else a negative value.
3083 */
3084 static int ust_app_channel_allocate(struct ust_app_session *ua_sess,
3085 struct ltt_ust_channel *uchan,
3086 enum lttng_ust_chan_type type, struct ltt_ust_session *usess,
3087 struct ust_app_channel **ua_chanp)
3088 {
3089 int ret = 0;
3090 struct lttng_ht_iter iter;
3091 struct lttng_ht_node_str *ua_chan_node;
3092 struct ust_app_channel *ua_chan;
3093
3094 /* Lookup channel in the ust app session */
3095 lttng_ht_lookup(ua_sess->channels, (void *)uchan->name, &iter);
3096 ua_chan_node = lttng_ht_iter_get_node_str(&iter);
3097 if (ua_chan_node != NULL) {
3098 ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
3099 goto end;
3100 }
3101
3102 ua_chan = alloc_ust_app_channel(uchan->name, ua_sess, &uchan->attr);
3103 if (ua_chan == NULL) {
3104 /* Only malloc can fail here */
3105 ret = -ENOMEM;
3106 goto error;
3107 }
3108 shadow_copy_channel(ua_chan, uchan);
3109
3110 /* Set channel type. */
3111 ua_chan->attr.type = type;
3112
3113 /* Only add the channel if successful on the tracer side. */
3114 lttng_ht_add_unique_str(ua_sess->channels, &ua_chan->node);
3115 end:
3116 if (ua_chanp) {
3117 *ua_chanp = ua_chan;
3118 }
3119
3120 /* Everything went well. */
3121 return 0;
3122
3123 error:
3124 return ret;
3125 }
3126
3127 /*
3128 * Create UST app event and create it on the tracer side.
3129 *
3130 * Called with ust app session mutex held.
3131 */
3132 static
3133 int create_ust_app_event(struct ust_app_session *ua_sess,
3134 struct ust_app_channel *ua_chan, struct ltt_ust_event *uevent,
3135 struct ust_app *app)
3136 {
3137 int ret = 0;
3138 struct ust_app_event *ua_event;
3139
3140 ua_event = alloc_ust_app_event(uevent->attr.name, &uevent->attr);
3141 if (ua_event == NULL) {
3142 /* Only failure mode of alloc_ust_app_event(). */
3143 ret = -ENOMEM;
3144 goto end;
3145 }
3146 shadow_copy_event(ua_event, uevent);
3147
3148 /* Create it on the tracer side */
3149 ret = create_ust_event(app, ua_sess, ua_chan, ua_event);
3150 if (ret < 0) {
3151 /*
3152 * Not found previously means that it does not exist on the
3153 * tracer. If the application reports that the event existed,
3154 * it means there is a bug in the sessiond or lttng-ust
3155 * (or corruption, etc.)
3156 */
3157 if (ret == -LTTNG_UST_ERR_EXIST) {
3158 ERR("Tracer for application reported that an event being created already existed: "
3159 "event_name = \"%s\", pid = %d, ppid = %d, uid = %d, gid = %d",
3160 uevent->attr.name,
3161 app->pid, app->ppid, app->uid,
3162 app->gid);
3163 }
3164 goto error;
3165 }
3166
3167 add_unique_ust_app_event(ua_chan, ua_event);
3168
3169 DBG2("UST app create event %s for PID %d completed", ua_event->name,
3170 app->pid);
3171
3172 end:
3173 return ret;
3174
3175 error:
3176 /* Valid. Calling here is already in a read side lock */
3177 delete_ust_app_event(-1, ua_event, app);
3178 return ret;
3179 }
3180
3181 /*
3182 * Create UST metadata and open it on the tracer side.
3183 *
3184 * Called with UST app session lock held and RCU read side lock.
3185 */
3186 static int create_ust_app_metadata(struct ust_app_session *ua_sess,
3187 struct ust_app *app, struct consumer_output *consumer)
3188 {
3189 int ret = 0;
3190 struct ust_app_channel *metadata;
3191 struct consumer_socket *socket;
3192 struct ust_registry_session *registry;
3193 struct ltt_session *session = NULL;
3194
3195 assert(ua_sess);
3196 assert(app);
3197 assert(consumer);
3198
3199 registry = get_session_registry(ua_sess);
3200 /* The UST app session is held registry shall not be null. */
3201 assert(registry);
3202
3203 pthread_mutex_lock(&registry->lock);
3204
3205 /* Metadata already exists for this registry or it was closed previously */
3206 if (registry->metadata_key || registry->metadata_closed) {
3207 ret = 0;
3208 goto error;
3209 }
3210
3211 /* Allocate UST metadata */
3212 metadata = alloc_ust_app_channel(DEFAULT_METADATA_NAME, ua_sess, NULL);
3213 if (!metadata) {
3214 /* malloc() failed */
3215 ret = -ENOMEM;
3216 goto error;
3217 }
3218
3219 memcpy(&metadata->attr, &ua_sess->metadata_attr, sizeof(metadata->attr));
3220
3221 /* Need one fd for the channel. */
3222 ret = lttng_fd_get(LTTNG_FD_APPS, 1);
3223 if (ret < 0) {
3224 ERR("Exhausted number of available FD upon create metadata");
3225 goto error;
3226 }
3227