9d82b8313bfc59701619378a22cb69550bfc5eb4
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-events.c
1 /*
2 * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License, version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 51
15 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #define _LGPL_SOURCE
19 #include <urcu.h>
20 #include <urcu/rculfhash.h>
21
22 #include <common/defaults.h>
23 #include <common/error.h>
24 #include <common/futex.h>
25 #include <common/unix.h>
26 #include <common/dynamic-buffer.h>
27 #include <common/hashtable/utils.h>
28 #include <common/sessiond-comm/sessiond-comm.h>
29 #include <common/macros.h>
30 #include <lttng/condition/condition.h>
31 #include <lttng/action/action-internal.h>
32 #include <lttng/notification/notification-internal.h>
33 #include <lttng/condition/condition-internal.h>
34 #include <lttng/condition/buffer-usage-internal.h>
35 #include <lttng/condition/session-consumed-size-internal.h>
36 #include <lttng/condition/session-rotation-internal.h>
37 #include <lttng/notification/channel-internal.h>
38
39 #include <time.h>
40 #include <unistd.h>
41 #include <assert.h>
42 #include <inttypes.h>
43 #include <fcntl.h>
44
45 #include "notification-thread.h"
46 #include "notification-thread-events.h"
47 #include "notification-thread-commands.h"
48 #include "lttng-sessiond.h"
49 #include "kernel.h"
50
51 #define CLIENT_POLL_MASK_IN (LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP)
52 #define CLIENT_POLL_MASK_IN_OUT (CLIENT_POLL_MASK_IN | LPOLLOUT)
53
54 enum lttng_object_type {
55 LTTNG_OBJECT_TYPE_UNKNOWN,
56 LTTNG_OBJECT_TYPE_NONE,
57 LTTNG_OBJECT_TYPE_CHANNEL,
58 LTTNG_OBJECT_TYPE_SESSION,
59 };
60
61 struct lttng_trigger_list_element {
62 /* No ownership of the trigger object is assumed. */
63 const struct lttng_trigger *trigger;
64 struct cds_list_head node;
65 };
66
67 struct lttng_channel_trigger_list {
68 struct channel_key channel_key;
69 /* List of struct lttng_trigger_list_element. */
70 struct cds_list_head list;
71 /* Node in the channel_triggers_ht */
72 struct cds_lfht_node channel_triggers_ht_node;
73 /* call_rcu delayed reclaim. */
74 struct rcu_head rcu_node;
75 };
76
77 /*
78 * List of triggers applying to a given session.
79 *
80 * See:
81 * - lttng_session_trigger_list_create()
82 * - lttng_session_trigger_list_build()
83 * - lttng_session_trigger_list_destroy()
84 * - lttng_session_trigger_list_add()
85 */
86 struct lttng_session_trigger_list {
87 /*
88 * Not owned by this; points to the session_info structure's
89 * session name.
90 */
91 const char *session_name;
92 /* List of struct lttng_trigger_list_element. */
93 struct cds_list_head list;
94 /* Node in the session_triggers_ht */
95 struct cds_lfht_node session_triggers_ht_node;
96 /*
97 * Weak reference to the notification system's session triggers
98 * hashtable.
99 *
100 * The session trigger list structure structure is owned by
101 * the session's session_info.
102 *
103 * The session_info is kept alive the the channel_infos holding a
104 * reference to it (reference counting). When those channels are
105 * destroyed (at runtime or on teardown), the reference they hold
106 * to the session_info are released. On destruction of session_info,
107 * session_info_destroy() will remove the list of triggers applying
108 * to this session from the notification system's state.
109 *
110 * This implies that the session_triggers_ht must be destroyed
111 * after the channels.
112 */
113 struct cds_lfht *session_triggers_ht;
114 /* Used for delayed RCU reclaim. */
115 struct rcu_head rcu_node;
116 };
117
118 struct lttng_trigger_ht_element {
119 struct lttng_trigger *trigger;
120 struct cds_lfht_node node;
121 /* call_rcu delayed reclaim. */
122 struct rcu_head rcu_node;
123 };
124
125 struct lttng_condition_list_element {
126 struct lttng_condition *condition;
127 struct cds_list_head node;
128 };
129
130 struct notification_client_list_element {
131 struct notification_client *client;
132 struct cds_list_head node;
133 };
134
135 struct notification_client_list {
136 const struct lttng_trigger *trigger;
137 struct cds_list_head list;
138 struct cds_lfht_node notification_trigger_ht_node;
139 /* call_rcu delayed reclaim. */
140 struct rcu_head rcu_node;
141 };
142
143 struct notification_client {
144 int socket;
145 /* Client protocol version. */
146 uint8_t major, minor;
147 uid_t uid;
148 gid_t gid;
149 /*
150 * Indicates if the credentials and versions of the client have been
151 * checked.
152 */
153 bool validated;
154 /*
155 * Conditions to which the client's notification channel is subscribed.
156 * List of struct lttng_condition_list_node. The condition member is
157 * owned by the client.
158 */
159 struct cds_list_head condition_list;
160 struct cds_lfht_node client_socket_ht_node;
161 struct {
162 struct {
163 /*
164 * During the reception of a message, the reception
165 * buffers' "size" is set to contain the current
166 * message's complete payload.
167 */
168 struct lttng_dynamic_buffer buffer;
169 /* Bytes left to receive for the current message. */
170 size_t bytes_to_receive;
171 /* Type of the message being received. */
172 enum lttng_notification_channel_message_type msg_type;
173 /*
174 * Indicates whether or not credentials are expected
175 * from the client.
176 */
177 bool expect_creds;
178 /*
179 * Indicates whether or not credentials were received
180 * from the client.
181 */
182 bool creds_received;
183 /* Only used during credentials reception. */
184 lttng_sock_cred creds;
185 } inbound;
186 struct {
187 /*
188 * Indicates whether or not a notification addressed to
189 * this client was dropped because a command reply was
190 * already buffered.
191 *
192 * A notification is dropped whenever the buffer is not
193 * empty.
194 */
195 bool dropped_notification;
196 /*
197 * Indicates whether or not a command reply is already
198 * buffered. In this case, it means that the client is
199 * not consuming command replies before emitting a new
200 * one. This could be caused by a protocol error or a
201 * misbehaving/malicious client.
202 */
203 bool queued_command_reply;
204 struct lttng_dynamic_buffer buffer;
205 } outbound;
206 } communication;
207 /* call_rcu delayed reclaim. */
208 struct rcu_head rcu_node;
209 };
210
211 struct channel_state_sample {
212 struct channel_key key;
213 struct cds_lfht_node channel_state_ht_node;
214 uint64_t highest_usage;
215 uint64_t lowest_usage;
216 uint64_t channel_total_consumed;
217 /* call_rcu delayed reclaim. */
218 struct rcu_head rcu_node;
219 };
220
221 static unsigned long hash_channel_key(struct channel_key *key);
222 static int evaluate_buffer_condition(const struct lttng_condition *condition,
223 struct lttng_evaluation **evaluation,
224 const struct notification_thread_state *state,
225 const struct channel_state_sample *previous_sample,
226 const struct channel_state_sample *latest_sample,
227 uint64_t previous_session_consumed_total,
228 uint64_t latest_session_consumed_total,
229 struct channel_info *channel_info);
230 static
231 int send_evaluation_to_clients(const struct lttng_trigger *trigger,
232 const struct lttng_evaluation *evaluation,
233 struct notification_client_list *client_list,
234 struct notification_thread_state *state,
235 uid_t channel_uid, gid_t channel_gid);
236
237
238 /* session_info API */
239 static
240 void session_info_destroy(void *_data);
241 static
242 void session_info_get(struct session_info *session_info);
243 static
244 void session_info_put(struct session_info *session_info);
245 static
246 struct session_info *session_info_create(const char *name,
247 uid_t uid, gid_t gid,
248 struct lttng_session_trigger_list *trigger_list,
249 struct cds_lfht *sessions_ht);
250 static
251 void session_info_add_channel(struct session_info *session_info,
252 struct channel_info *channel_info);
253 static
254 void session_info_remove_channel(struct session_info *session_info,
255 struct channel_info *channel_info);
256
257 /* lttng_session_trigger_list API */
258 static
259 struct lttng_session_trigger_list *lttng_session_trigger_list_create(
260 const char *session_name,
261 struct cds_lfht *session_triggers_ht);
262 static
263 struct lttng_session_trigger_list *lttng_session_trigger_list_build(
264 const struct notification_thread_state *state,
265 const char *session_name);
266 static
267 void lttng_session_trigger_list_destroy(
268 struct lttng_session_trigger_list *list);
269 static
270 int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list,
271 const struct lttng_trigger *trigger);
272
273
274 static
275 int match_client(struct cds_lfht_node *node, const void *key)
276 {
277 /* This double-cast is intended to supress pointer-to-cast warning. */
278 int socket = (int) (intptr_t) key;
279 struct notification_client *client;
280
281 client = caa_container_of(node, struct notification_client,
282 client_socket_ht_node);
283
284 return !!(client->socket == socket);
285 }
286
287 static
288 int match_channel_trigger_list(struct cds_lfht_node *node, const void *key)
289 {
290 struct channel_key *channel_key = (struct channel_key *) key;
291 struct lttng_channel_trigger_list *trigger_list;
292
293 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
294 channel_triggers_ht_node);
295
296 return !!((channel_key->key == trigger_list->channel_key.key) &&
297 (channel_key->domain == trigger_list->channel_key.domain));
298 }
299
300 static
301 int match_session_trigger_list(struct cds_lfht_node *node, const void *key)
302 {
303 const char *session_name = (const char *) key;
304 struct lttng_session_trigger_list *trigger_list;
305
306 trigger_list = caa_container_of(node, struct lttng_session_trigger_list,
307 session_triggers_ht_node);
308
309 return !!(strcmp(trigger_list->session_name, session_name) == 0);
310 }
311
312 static
313 int match_channel_state_sample(struct cds_lfht_node *node, const void *key)
314 {
315 struct channel_key *channel_key = (struct channel_key *) key;
316 struct channel_state_sample *sample;
317
318 sample = caa_container_of(node, struct channel_state_sample,
319 channel_state_ht_node);
320
321 return !!((channel_key->key == sample->key.key) &&
322 (channel_key->domain == sample->key.domain));
323 }
324
325 static
326 int match_channel_info(struct cds_lfht_node *node, const void *key)
327 {
328 struct channel_key *channel_key = (struct channel_key *) key;
329 struct channel_info *channel_info;
330
331 channel_info = caa_container_of(node, struct channel_info,
332 channels_ht_node);
333
334 return !!((channel_key->key == channel_info->key.key) &&
335 (channel_key->domain == channel_info->key.domain));
336 }
337
338 static
339 int match_condition(struct cds_lfht_node *node, const void *key)
340 {
341 struct lttng_condition *condition_key = (struct lttng_condition *) key;
342 struct lttng_trigger_ht_element *trigger;
343 struct lttng_condition *condition;
344
345 trigger = caa_container_of(node, struct lttng_trigger_ht_element,
346 node);
347 condition = lttng_trigger_get_condition(trigger->trigger);
348 assert(condition);
349
350 return !!lttng_condition_is_equal(condition_key, condition);
351 }
352
353 static
354 int match_client_list_condition(struct cds_lfht_node *node, const void *key)
355 {
356 struct lttng_condition *condition_key = (struct lttng_condition *) key;
357 struct notification_client_list *client_list;
358 const struct lttng_condition *condition;
359
360 assert(condition_key);
361
362 client_list = caa_container_of(node, struct notification_client_list,
363 notification_trigger_ht_node);
364 condition = lttng_trigger_get_const_condition(client_list->trigger);
365
366 return !!lttng_condition_is_equal(condition_key, condition);
367 }
368
369 static
370 int match_session(struct cds_lfht_node *node, const void *key)
371 {
372 const char *name = key;
373 struct session_info *session_info = caa_container_of(
374 node, struct session_info, sessions_ht_node);
375
376 return !strcmp(session_info->name, name);
377 }
378
379 static
380 unsigned long lttng_condition_buffer_usage_hash(
381 const struct lttng_condition *_condition)
382 {
383 unsigned long hash;
384 unsigned long condition_type;
385 struct lttng_condition_buffer_usage *condition;
386
387 condition = container_of(_condition,
388 struct lttng_condition_buffer_usage, parent);
389
390 condition_type = (unsigned long) condition->parent.type;
391 hash = hash_key_ulong((void *) condition_type, lttng_ht_seed);
392 if (condition->session_name) {
393 hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
394 }
395 if (condition->channel_name) {
396 hash ^= hash_key_str(condition->channel_name, lttng_ht_seed);
397 }
398 if (condition->domain.set) {
399 hash ^= hash_key_ulong(
400 (void *) condition->domain.type,
401 lttng_ht_seed);
402 }
403 if (condition->threshold_ratio.set) {
404 uint64_t val;
405
406 val = condition->threshold_ratio.value * (double) UINT32_MAX;
407 hash ^= hash_key_u64(&val, lttng_ht_seed);
408 } else if (condition->threshold_bytes.set) {
409 uint64_t val;
410
411 val = condition->threshold_bytes.value;
412 hash ^= hash_key_u64(&val, lttng_ht_seed);
413 }
414 return hash;
415 }
416
417 static
418 unsigned long lttng_condition_session_consumed_size_hash(
419 const struct lttng_condition *_condition)
420 {
421 unsigned long hash;
422 unsigned long condition_type =
423 (unsigned long) LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE;
424 struct lttng_condition_session_consumed_size *condition;
425 uint64_t val;
426
427 condition = container_of(_condition,
428 struct lttng_condition_session_consumed_size, parent);
429
430 hash = hash_key_ulong((void *) condition_type, lttng_ht_seed);
431 if (condition->session_name) {
432 hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
433 }
434 val = condition->consumed_threshold_bytes.value;
435 hash ^= hash_key_u64(&val, lttng_ht_seed);
436 return hash;
437 }
438
439 static
440 unsigned long lttng_condition_session_rotation_hash(
441 const struct lttng_condition *_condition)
442 {
443 unsigned long hash, condition_type;
444 struct lttng_condition_session_rotation *condition;
445
446 condition = container_of(_condition,
447 struct lttng_condition_session_rotation, parent);
448 condition_type = (unsigned long) condition->parent.type;
449 hash = hash_key_ulong((void *) condition_type, lttng_ht_seed);
450 assert(condition->session_name);
451 hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
452 return hash;
453 }
454
455 /*
456 * The lttng_condition hashing code is kept in this file (rather than
457 * condition.c) since it makes use of GPLv2 code (hashtable utils), which we
458 * don't want to link in liblttng-ctl.
459 */
460 static
461 unsigned long lttng_condition_hash(const struct lttng_condition *condition)
462 {
463 switch (condition->type) {
464 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
465 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
466 return lttng_condition_buffer_usage_hash(condition);
467 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
468 return lttng_condition_session_consumed_size_hash(condition);
469 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
470 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
471 return lttng_condition_session_rotation_hash(condition);
472 default:
473 ERR("[notification-thread] Unexpected condition type caught");
474 abort();
475 }
476 }
477
478 static
479 unsigned long hash_channel_key(struct channel_key *key)
480 {
481 unsigned long key_hash = hash_key_u64(&key->key, lttng_ht_seed);
482 unsigned long domain_hash = hash_key_ulong(
483 (void *) (unsigned long) key->domain, lttng_ht_seed);
484
485 return key_hash ^ domain_hash;
486 }
487
488 /*
489 * Get the type of object to which a given condition applies. Bindings let
490 * the notification system evaluate a trigger's condition when a given
491 * object's state is updated.
492 *
493 * For instance, a condition bound to a channel will be evaluated everytime
494 * the channel's state is changed by a channel monitoring sample.
495 */
496 static
497 enum lttng_object_type get_condition_binding_object(
498 const struct lttng_condition *condition)
499 {
500 switch (lttng_condition_get_type(condition)) {
501 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
502 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
503 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
504 return LTTNG_OBJECT_TYPE_CHANNEL;
505 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
506 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
507 return LTTNG_OBJECT_TYPE_SESSION;
508 default:
509 return LTTNG_OBJECT_TYPE_UNKNOWN;
510 }
511 }
512
513 static
514 void free_channel_info_rcu(struct rcu_head *node)
515 {
516 free(caa_container_of(node, struct channel_info, rcu_node));
517 }
518
519 static
520 void channel_info_destroy(struct channel_info *channel_info)
521 {
522 if (!channel_info) {
523 return;
524 }
525
526 if (channel_info->session_info) {
527 session_info_remove_channel(channel_info->session_info,
528 channel_info);
529 session_info_put(channel_info->session_info);
530 }
531 if (channel_info->name) {
532 free(channel_info->name);
533 }
534 call_rcu(&channel_info->rcu_node, free_channel_info_rcu);
535 }
536
537 static
538 void free_session_info_rcu(struct rcu_head *node)
539 {
540 free(caa_container_of(node, struct session_info, rcu_node));
541 }
542
543 /* Don't call directly, use the ref-counting mechanism. */
544 static
545 void session_info_destroy(void *_data)
546 {
547 struct session_info *session_info = _data;
548 int ret;
549
550 assert(session_info);
551 if (session_info->channel_infos_ht) {
552 ret = cds_lfht_destroy(session_info->channel_infos_ht, NULL);
553 if (ret) {
554 ERR("[notification-thread] Failed to destroy channel information hash table");
555 }
556 }
557 lttng_session_trigger_list_destroy(session_info->trigger_list);
558
559 rcu_read_lock();
560 cds_lfht_del(session_info->sessions_ht,
561 &session_info->sessions_ht_node);
562 rcu_read_unlock();
563 free(session_info->name);
564 call_rcu(&session_info->rcu_node, free_session_info_rcu);
565 }
566
567 static
568 void session_info_get(struct session_info *session_info)
569 {
570 if (!session_info) {
571 return;
572 }
573 lttng_ref_get(&session_info->ref);
574 }
575
576 static
577 void session_info_put(struct session_info *session_info)
578 {
579 if (!session_info) {
580 return;
581 }
582 lttng_ref_put(&session_info->ref);
583 }
584
585 static
586 struct session_info *session_info_create(const char *name, uid_t uid, gid_t gid,
587 struct lttng_session_trigger_list *trigger_list,
588 struct cds_lfht *sessions_ht)
589 {
590 struct session_info *session_info;
591
592 assert(name);
593
594 session_info = zmalloc(sizeof(*session_info));
595 if (!session_info) {
596 goto end;
597 }
598 lttng_ref_init(&session_info->ref, session_info_destroy);
599
600 session_info->channel_infos_ht = cds_lfht_new(DEFAULT_HT_SIZE,
601 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
602 if (!session_info->channel_infos_ht) {
603 goto error;
604 }
605
606 cds_lfht_node_init(&session_info->sessions_ht_node);
607 session_info->name = strdup(name);
608 if (!session_info->name) {
609 goto error;
610 }
611 session_info->uid = uid;
612 session_info->gid = gid;
613 session_info->trigger_list = trigger_list;
614 session_info->sessions_ht = sessions_ht;
615 end:
616 return session_info;
617 error:
618 session_info_put(session_info);
619 return NULL;
620 }
621
622 static
623 void session_info_add_channel(struct session_info *session_info,
624 struct channel_info *channel_info)
625 {
626 rcu_read_lock();
627 cds_lfht_add(session_info->channel_infos_ht,
628 hash_channel_key(&channel_info->key),
629 &channel_info->session_info_channels_ht_node);
630 rcu_read_unlock();
631 }
632
633 static
634 void session_info_remove_channel(struct session_info *session_info,
635 struct channel_info *channel_info)
636 {
637 rcu_read_lock();
638 cds_lfht_del(session_info->channel_infos_ht,
639 &channel_info->session_info_channels_ht_node);
640 rcu_read_unlock();
641 }
642
643 static
644 struct channel_info *channel_info_create(const char *channel_name,
645 struct channel_key *channel_key, uint64_t channel_capacity,
646 struct session_info *session_info)
647 {
648 struct channel_info *channel_info = zmalloc(sizeof(*channel_info));
649
650 if (!channel_info) {
651 goto end;
652 }
653
654 cds_lfht_node_init(&channel_info->channels_ht_node);
655 cds_lfht_node_init(&channel_info->session_info_channels_ht_node);
656 memcpy(&channel_info->key, channel_key, sizeof(*channel_key));
657 channel_info->capacity = channel_capacity;
658
659 channel_info->name = strdup(channel_name);
660 if (!channel_info->name) {
661 goto error;
662 }
663
664 /*
665 * Set the references between session and channel infos:
666 * - channel_info holds a strong reference to session_info
667 * - session_info holds a weak reference to channel_info
668 */
669 session_info_get(session_info);
670 session_info_add_channel(session_info, channel_info);
671 channel_info->session_info = session_info;
672 end:
673 return channel_info;
674 error:
675 channel_info_destroy(channel_info);
676 return NULL;
677 }
678
679 /* RCU read lock must be held by the caller. */
680 static
681 struct notification_client_list *get_client_list_from_condition(
682 struct notification_thread_state *state,
683 const struct lttng_condition *condition)
684 {
685 struct cds_lfht_node *node;
686 struct cds_lfht_iter iter;
687
688 cds_lfht_lookup(state->notification_trigger_clients_ht,
689 lttng_condition_hash(condition),
690 match_client_list_condition,
691 condition,
692 &iter);
693 node = cds_lfht_iter_get_node(&iter);
694
695 return node ? caa_container_of(node,
696 struct notification_client_list,
697 notification_trigger_ht_node) : NULL;
698 }
699
700 /* This function must be called with the RCU read lock held. */
701 static
702 int evaluate_channel_condition_for_client(
703 const struct lttng_condition *condition,
704 struct notification_thread_state *state,
705 struct lttng_evaluation **evaluation,
706 uid_t *session_uid, gid_t *session_gid)
707 {
708 int ret;
709 struct cds_lfht_iter iter;
710 struct cds_lfht_node *node;
711 struct channel_info *channel_info = NULL;
712 struct channel_key *channel_key = NULL;
713 struct channel_state_sample *last_sample = NULL;
714 struct lttng_channel_trigger_list *channel_trigger_list = NULL;
715
716 /* Find the channel associated with the condition. */
717 cds_lfht_for_each_entry(state->channel_triggers_ht, &iter,
718 channel_trigger_list, channel_triggers_ht_node) {
719 struct lttng_trigger_list_element *element;
720
721 cds_list_for_each_entry(element, &channel_trigger_list->list, node) {
722 const struct lttng_condition *current_condition =
723 lttng_trigger_get_const_condition(
724 element->trigger);
725
726 assert(current_condition);
727 if (!lttng_condition_is_equal(condition,
728 current_condition)) {
729 continue;
730 }
731
732 /* Found the trigger, save the channel key. */
733 channel_key = &channel_trigger_list->channel_key;
734 break;
735 }
736 if (channel_key) {
737 /* The channel key was found stop iteration. */
738 break;
739 }
740 }
741
742 if (!channel_key){
743 /* No channel found; normal exit. */
744 DBG("[notification-thread] No known channel associated with newly subscribed-to condition");
745 ret = 0;
746 goto end;
747 }
748
749 /* Fetch channel info for the matching channel. */
750 cds_lfht_lookup(state->channels_ht,
751 hash_channel_key(channel_key),
752 match_channel_info,
753 channel_key,
754 &iter);
755 node = cds_lfht_iter_get_node(&iter);
756 assert(node);
757 channel_info = caa_container_of(node, struct channel_info,
758 channels_ht_node);
759
760 /* Retrieve the channel's last sample, if it exists. */
761 cds_lfht_lookup(state->channel_state_ht,
762 hash_channel_key(channel_key),
763 match_channel_state_sample,
764 channel_key,
765 &iter);
766 node = cds_lfht_iter_get_node(&iter);
767 if (node) {
768 last_sample = caa_container_of(node,
769 struct channel_state_sample,
770 channel_state_ht_node);
771 } else {
772 /* Nothing to evaluate, no sample was ever taken. Normal exit */
773 DBG("[notification-thread] No channel sample associated with newly subscribed-to condition");
774 ret = 0;
775 goto end;
776 }
777
778 ret = evaluate_buffer_condition(condition, evaluation, state,
779 NULL, last_sample,
780 0, channel_info->session_info->consumed_data_size,
781 channel_info);
782 if (ret) {
783 WARN("[notification-thread] Fatal error occurred while evaluating a newly subscribed-to condition");
784 goto end;
785 }
786
787 *session_uid = channel_info->session_info->uid;
788 *session_gid = channel_info->session_info->gid;
789 end:
790 return ret;
791 }
792
793 static
794 const char *get_condition_session_name(const struct lttng_condition *condition)
795 {
796 const char *session_name = NULL;
797 enum lttng_condition_status status;
798
799 switch (lttng_condition_get_type(condition)) {
800 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
801 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
802 status = lttng_condition_buffer_usage_get_session_name(
803 condition, &session_name);
804 break;
805 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
806 status = lttng_condition_session_consumed_size_get_session_name(
807 condition, &session_name);
808 break;
809 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
810 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
811 status = lttng_condition_session_rotation_get_session_name(
812 condition, &session_name);
813 break;
814 default:
815 abort();
816 }
817 if (status != LTTNG_CONDITION_STATUS_OK) {
818 ERR("[notification-thread] Failed to retrieve session rotation condition's session name");
819 goto end;
820 }
821 end:
822 return session_name;
823 }
824
825 /* This function must be called with the RCU read lock held. */
826 static
827 int evaluate_session_condition_for_client(
828 const struct lttng_condition *condition,
829 struct notification_thread_state *state,
830 struct lttng_evaluation **evaluation,
831 uid_t *session_uid, gid_t *session_gid)
832 {
833 int ret;
834 struct cds_lfht_iter iter;
835 struct cds_lfht_node *node;
836 const char *session_name;
837 struct session_info *session_info = NULL;
838
839 session_name = get_condition_session_name(condition);
840
841 /* Find the session associated with the trigger. */
842 cds_lfht_lookup(state->sessions_ht,
843 hash_key_str(session_name, lttng_ht_seed),
844 match_session,
845 session_name,
846 &iter);
847 node = cds_lfht_iter_get_node(&iter);
848 if (!node) {
849 DBG("[notification-thread] No known session matching name \"%s\"",
850 session_name);
851 ret = 0;
852 goto end;
853 }
854
855 session_info = caa_container_of(node, struct session_info,
856 sessions_ht_node);
857 session_info_get(session_info);
858
859 /*
860 * Evaluation is performed in-line here since only one type of
861 * session-bound condition is handled for the moment.
862 */
863 switch (lttng_condition_get_type(condition)) {
864 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
865 if (!session_info->rotation.ongoing) {
866 ret = 0;
867 goto end_session_put;
868 }
869
870 *evaluation = lttng_evaluation_session_rotation_ongoing_create(
871 session_info->rotation.id);
872 if (!*evaluation) {
873 /* Fatal error. */
874 ERR("[notification-thread] Failed to create session rotation ongoing evaluation for session \"%s\"",
875 session_info->name);
876 ret = -1;
877 goto end_session_put;
878 }
879 ret = 0;
880 break;
881 default:
882 ret = 0;
883 goto end_session_put;
884 }
885
886 *session_uid = session_info->uid;
887 *session_gid = session_info->gid;
888
889 end_session_put:
890 session_info_put(session_info);
891 end:
892 return ret;
893 }
894
895 /* This function must be called with the RCU read lock held. */
896 static
897 int evaluate_condition_for_client(const struct lttng_trigger *trigger,
898 const struct lttng_condition *condition,
899 struct notification_client *client,
900 struct notification_thread_state *state)
901 {
902 int ret;
903 struct lttng_evaluation *evaluation = NULL;
904 struct notification_client_list client_list = { 0 };
905 struct notification_client_list_element client_list_element = { 0 };
906 uid_t object_uid = 0;
907 gid_t object_gid = 0;
908
909 assert(trigger);
910 assert(condition);
911 assert(client);
912 assert(state);
913
914 switch (get_condition_binding_object(condition)) {
915 case LTTNG_OBJECT_TYPE_SESSION:
916 ret = evaluate_session_condition_for_client(condition, state,
917 &evaluation, &object_uid, &object_gid);
918 break;
919 case LTTNG_OBJECT_TYPE_CHANNEL:
920 ret = evaluate_channel_condition_for_client(condition, state,
921 &evaluation, &object_uid, &object_gid);
922 break;
923 case LTTNG_OBJECT_TYPE_NONE:
924 ret = 0;
925 goto end;
926 case LTTNG_OBJECT_TYPE_UNKNOWN:
927 default:
928 ret = -1;
929 goto end;
930 }
931
932 if (!evaluation) {
933 /* Evaluation yielded nothing. Normal exit. */
934 DBG("[notification-thread] Newly subscribed-to condition evaluated to false, nothing to report to client");
935 ret = 0;
936 goto end;
937 }
938
939 /*
940 * Create a temporary client list with the client currently
941 * subscribing.
942 */
943 cds_lfht_node_init(&client_list.notification_trigger_ht_node);
944 CDS_INIT_LIST_HEAD(&client_list.list);
945 client_list.trigger = trigger;
946
947 CDS_INIT_LIST_HEAD(&client_list_element.node);
948 client_list_element.client = client;
949 cds_list_add(&client_list_element.node, &client_list.list);
950
951 /* Send evaluation result to the newly-subscribed client. */
952 DBG("[notification-thread] Newly subscribed-to condition evaluated to true, notifying client");
953 ret = send_evaluation_to_clients(trigger, evaluation, &client_list,
954 state, object_uid, object_gid);
955
956 end:
957 return ret;
958 }
959
960 static
961 int notification_thread_client_subscribe(struct notification_client *client,
962 struct lttng_condition *condition,
963 struct notification_thread_state *state,
964 enum lttng_notification_channel_status *_status)
965 {
966 int ret = 0;
967 struct notification_client_list *client_list;
968 struct lttng_condition_list_element *condition_list_element = NULL;
969 struct notification_client_list_element *client_list_element = NULL;
970 enum lttng_notification_channel_status status =
971 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
972
973 /*
974 * Ensure that the client has not already subscribed to this condition
975 * before.
976 */
977 cds_list_for_each_entry(condition_list_element, &client->condition_list, node) {
978 if (lttng_condition_is_equal(condition_list_element->condition,
979 condition)) {
980 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ALREADY_SUBSCRIBED;
981 goto end;
982 }
983 }
984
985 condition_list_element = zmalloc(sizeof(*condition_list_element));
986 if (!condition_list_element) {
987 ret = -1;
988 goto error;
989 }
990 client_list_element = zmalloc(sizeof(*client_list_element));
991 if (!client_list_element) {
992 ret = -1;
993 goto error;
994 }
995
996 rcu_read_lock();
997
998 /*
999 * Add the newly-subscribed condition to the client's subscription list.
1000 */
1001 CDS_INIT_LIST_HEAD(&condition_list_element->node);
1002 condition_list_element->condition = condition;
1003 cds_list_add(&condition_list_element->node, &client->condition_list);
1004
1005 client_list = get_client_list_from_condition(state, condition);
1006 if (!client_list) {
1007 /*
1008 * No notification-emiting trigger registered with this
1009 * condition. We don't evaluate the condition right away
1010 * since this trigger is not registered yet.
1011 */
1012 free(client_list_element);
1013 goto end_unlock;
1014 }
1015
1016 /*
1017 * The condition to which the client just subscribed is evaluated
1018 * at this point so that conditions that are already TRUE result
1019 * in a notification being sent out.
1020 */
1021 if (evaluate_condition_for_client(client_list->trigger, condition,
1022 client, state)) {
1023 WARN("[notification-thread] Evaluation of a condition on client subscription failed, aborting.");
1024 ret = -1;
1025 free(client_list_element);
1026 goto end_unlock;
1027 }
1028
1029 /*
1030 * Add the client to the list of clients interested in a given trigger
1031 * if a "notification" trigger with a corresponding condition was
1032 * added prior.
1033 */
1034 client_list_element->client = client;
1035 CDS_INIT_LIST_HEAD(&client_list_element->node);
1036 cds_list_add(&client_list_element->node, &client_list->list);
1037 end_unlock:
1038 rcu_read_unlock();
1039 end:
1040 if (_status) {
1041 *_status = status;
1042 }
1043 return ret;
1044 error:
1045 free(condition_list_element);
1046 free(client_list_element);
1047 return ret;
1048 }
1049
1050 static
1051 int notification_thread_client_unsubscribe(
1052 struct notification_client *client,
1053 struct lttng_condition *condition,
1054 struct notification_thread_state *state,
1055 enum lttng_notification_channel_status *_status)
1056 {
1057 struct notification_client_list *client_list;
1058 struct lttng_condition_list_element *condition_list_element,
1059 *condition_tmp;
1060 struct notification_client_list_element *client_list_element,
1061 *client_tmp;
1062 bool condition_found = false;
1063 enum lttng_notification_channel_status status =
1064 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
1065
1066 /* Remove the condition from the client's condition list. */
1067 cds_list_for_each_entry_safe(condition_list_element, condition_tmp,
1068 &client->condition_list, node) {
1069 if (!lttng_condition_is_equal(condition_list_element->condition,
1070 condition)) {
1071 continue;
1072 }
1073
1074 cds_list_del(&condition_list_element->node);
1075 /*
1076 * The caller may be iterating on the client's conditions to
1077 * tear down a client's connection. In this case, the condition
1078 * will be destroyed at the end.
1079 */
1080 if (condition != condition_list_element->condition) {
1081 lttng_condition_destroy(
1082 condition_list_element->condition);
1083 }
1084 free(condition_list_element);
1085 condition_found = true;
1086 break;
1087 }
1088
1089 if (!condition_found) {
1090 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNKNOWN_CONDITION;
1091 goto end;
1092 }
1093
1094 /*
1095 * Remove the client from the list of clients interested the trigger
1096 * matching the condition.
1097 */
1098 rcu_read_lock();
1099 client_list = get_client_list_from_condition(state, condition);
1100 if (!client_list) {
1101 goto end_unlock;
1102 }
1103
1104 cds_list_for_each_entry_safe(client_list_element, client_tmp,
1105 &client_list->list, node) {
1106 if (client_list_element->client->socket != client->socket) {
1107 continue;
1108 }
1109 cds_list_del(&client_list_element->node);
1110 free(client_list_element);
1111 break;
1112 }
1113 end_unlock:
1114 rcu_read_unlock();
1115 end:
1116 lttng_condition_destroy(condition);
1117 if (_status) {
1118 *_status = status;
1119 }
1120 return 0;
1121 }
1122
1123 static
1124 void free_notification_client_rcu(struct rcu_head *node)
1125 {
1126 free(caa_container_of(node, struct notification_client, rcu_node));
1127 }
1128
1129 static
1130 void notification_client_destroy(struct notification_client *client,
1131 struct notification_thread_state *state)
1132 {
1133 struct lttng_condition_list_element *condition_list_element, *tmp;
1134
1135 if (!client) {
1136 return;
1137 }
1138
1139 /* Release all conditions to which the client was subscribed. */
1140 cds_list_for_each_entry_safe(condition_list_element, tmp,
1141 &client->condition_list, node) {
1142 (void) notification_thread_client_unsubscribe(client,
1143 condition_list_element->condition, state, NULL);
1144 }
1145
1146 if (client->socket >= 0) {
1147 (void) lttcomm_close_unix_sock(client->socket);
1148 }
1149 lttng_dynamic_buffer_reset(&client->communication.inbound.buffer);
1150 lttng_dynamic_buffer_reset(&client->communication.outbound.buffer);
1151 call_rcu(&client->rcu_node, free_notification_client_rcu);
1152 }
1153
1154 /*
1155 * Call with rcu_read_lock held (and hold for the lifetime of the returned
1156 * client pointer).
1157 */
1158 static
1159 struct notification_client *get_client_from_socket(int socket,
1160 struct notification_thread_state *state)
1161 {
1162 struct cds_lfht_iter iter;
1163 struct cds_lfht_node *node;
1164 struct notification_client *client = NULL;
1165
1166 cds_lfht_lookup(state->client_socket_ht,
1167 hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed),
1168 match_client,
1169 (void *) (unsigned long) socket,
1170 &iter);
1171 node = cds_lfht_iter_get_node(&iter);
1172 if (!node) {
1173 goto end;
1174 }
1175
1176 client = caa_container_of(node, struct notification_client,
1177 client_socket_ht_node);
1178 end:
1179 return client;
1180 }
1181
1182 static
1183 bool buffer_usage_condition_applies_to_channel(
1184 const struct lttng_condition *condition,
1185 const struct channel_info *channel_info)
1186 {
1187 enum lttng_condition_status status;
1188 enum lttng_domain_type condition_domain;
1189 const char *condition_session_name = NULL;
1190 const char *condition_channel_name = NULL;
1191
1192 status = lttng_condition_buffer_usage_get_domain_type(condition,
1193 &condition_domain);
1194 assert(status == LTTNG_CONDITION_STATUS_OK);
1195 if (channel_info->key.domain != condition_domain) {
1196 goto fail;
1197 }
1198
1199 status = lttng_condition_buffer_usage_get_session_name(
1200 condition, &condition_session_name);
1201 assert((status == LTTNG_CONDITION_STATUS_OK) && condition_session_name);
1202
1203 status = lttng_condition_buffer_usage_get_channel_name(
1204 condition, &condition_channel_name);
1205 assert((status == LTTNG_CONDITION_STATUS_OK) && condition_channel_name);
1206
1207 if (strcmp(channel_info->session_info->name, condition_session_name)) {
1208 goto fail;
1209 }
1210 if (strcmp(channel_info->name, condition_channel_name)) {
1211 goto fail;
1212 }
1213
1214 return true;
1215 fail:
1216 return false;
1217 }
1218
1219 static
1220 bool session_consumed_size_condition_applies_to_channel(
1221 const struct lttng_condition *condition,
1222 const struct channel_info *channel_info)
1223 {
1224 enum lttng_condition_status status;
1225 const char *condition_session_name = NULL;
1226
1227 status = lttng_condition_session_consumed_size_get_session_name(
1228 condition, &condition_session_name);
1229 assert((status == LTTNG_CONDITION_STATUS_OK) && condition_session_name);
1230
1231 if (strcmp(channel_info->session_info->name, condition_session_name)) {
1232 goto fail;
1233 }
1234
1235 return true;
1236 fail:
1237 return false;
1238 }
1239
1240 static
1241 bool trigger_applies_to_channel(const struct lttng_trigger *trigger,
1242 const struct channel_info *channel_info)
1243 {
1244 const struct lttng_condition *condition;
1245 bool trigger_applies;
1246
1247 condition = lttng_trigger_get_const_condition(trigger);
1248 if (!condition) {
1249 goto fail;
1250 }
1251
1252 switch (lttng_condition_get_type(condition)) {
1253 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
1254 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
1255 trigger_applies = buffer_usage_condition_applies_to_channel(
1256 condition, channel_info);
1257 break;
1258 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
1259 trigger_applies = session_consumed_size_condition_applies_to_channel(
1260 condition, channel_info);
1261 break;
1262 default:
1263 goto fail;
1264 }
1265
1266 return trigger_applies;
1267 fail:
1268 return false;
1269 }
1270
1271 static
1272 bool trigger_applies_to_client(struct lttng_trigger *trigger,
1273 struct notification_client *client)
1274 {
1275 bool applies = false;
1276 struct lttng_condition_list_element *condition_list_element;
1277
1278 cds_list_for_each_entry(condition_list_element, &client->condition_list,
1279 node) {
1280 applies = lttng_condition_is_equal(
1281 condition_list_element->condition,
1282 lttng_trigger_get_condition(trigger));
1283 if (applies) {
1284 break;
1285 }
1286 }
1287 return applies;
1288 }
1289
1290 /* Must be called with RCU read lock held. */
1291 static
1292 struct lttng_session_trigger_list *get_session_trigger_list(
1293 struct notification_thread_state *state,
1294 const char *session_name)
1295 {
1296 struct lttng_session_trigger_list *list = NULL;
1297 struct cds_lfht_node *node;
1298 struct cds_lfht_iter iter;
1299
1300 cds_lfht_lookup(state->session_triggers_ht,
1301 hash_key_str(session_name, lttng_ht_seed),
1302 match_session_trigger_list,
1303 session_name,
1304 &iter);
1305 node = cds_lfht_iter_get_node(&iter);
1306 if (!node) {
1307 /*
1308 * Not an error, the list of triggers applying to that session
1309 * will be initialized when the session is created.
1310 */
1311 DBG("[notification-thread] No trigger list found for session \"%s\" as it is not yet known to the notification system",
1312 session_name);
1313 goto end;
1314 }
1315
1316 list = caa_container_of(node,
1317 struct lttng_session_trigger_list,
1318 session_triggers_ht_node);
1319 end:
1320 return list;
1321 }
1322
1323 /*
1324 * Allocate an empty lttng_session_trigger_list for the session named
1325 * 'session_name'.
1326 *
1327 * No ownership of 'session_name' is assumed by the session trigger list.
1328 * It is the caller's responsability to ensure the session name is alive
1329 * for as long as this list is.
1330 */
1331 static
1332 struct lttng_session_trigger_list *lttng_session_trigger_list_create(
1333 const char *session_name,
1334 struct cds_lfht *session_triggers_ht)
1335 {
1336 struct lttng_session_trigger_list *list;
1337
1338 list = zmalloc(sizeof(*list));
1339 if (!list) {
1340 goto end;
1341 }
1342 list->session_name = session_name;
1343 CDS_INIT_LIST_HEAD(&list->list);
1344 cds_lfht_node_init(&list->session_triggers_ht_node);
1345 list->session_triggers_ht = session_triggers_ht;
1346
1347 rcu_read_lock();
1348 /* Publish the list through the session_triggers_ht. */
1349 cds_lfht_add(session_triggers_ht,
1350 hash_key_str(session_name, lttng_ht_seed),
1351 &list->session_triggers_ht_node);
1352 rcu_read_unlock();
1353 end:
1354 return list;
1355 }
1356
1357 static
1358 void free_session_trigger_list_rcu(struct rcu_head *node)
1359 {
1360 free(caa_container_of(node, struct lttng_session_trigger_list,
1361 rcu_node));
1362 }
1363
1364 static
1365 void lttng_session_trigger_list_destroy(struct lttng_session_trigger_list *list)
1366 {
1367 struct lttng_trigger_list_element *trigger_list_element, *tmp;
1368
1369 /* Empty the list element by element, and then free the list itself. */
1370 cds_list_for_each_entry_safe(trigger_list_element, tmp,
1371 &list->list, node) {
1372 cds_list_del(&trigger_list_element->node);
1373 free(trigger_list_element);
1374 }
1375 rcu_read_lock();
1376 /* Unpublish the list from the session_triggers_ht. */
1377 cds_lfht_del(list->session_triggers_ht,
1378 &list->session_triggers_ht_node);
1379 rcu_read_unlock();
1380 call_rcu(&list->rcu_node, free_session_trigger_list_rcu);
1381 }
1382
1383 static
1384 int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list,
1385 const struct lttng_trigger *trigger)
1386 {
1387 int ret = 0;
1388 struct lttng_trigger_list_element *new_element =
1389 zmalloc(sizeof(*new_element));
1390
1391 if (!new_element) {
1392 ret = -1;
1393 goto end;
1394 }
1395 CDS_INIT_LIST_HEAD(&new_element->node);
1396 new_element->trigger = trigger;
1397 cds_list_add(&new_element->node, &list->list);
1398 end:
1399 return ret;
1400 }
1401
1402 static
1403 bool trigger_applies_to_session(const struct lttng_trigger *trigger,
1404 const char *session_name)
1405 {
1406 bool applies = false;
1407 const struct lttng_condition *condition;
1408
1409 condition = lttng_trigger_get_const_condition(trigger);
1410 switch (lttng_condition_get_type(condition)) {
1411 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
1412 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
1413 {
1414 enum lttng_condition_status condition_status;
1415 const char *condition_session_name;
1416
1417 condition_status = lttng_condition_session_rotation_get_session_name(
1418 condition, &condition_session_name);
1419 if (condition_status != LTTNG_CONDITION_STATUS_OK) {
1420 ERR("[notification-thread] Failed to retrieve session rotation condition's session name");
1421 goto end;
1422 }
1423
1424 assert(condition_session_name);
1425 applies = !strcmp(condition_session_name, session_name);
1426 break;
1427 }
1428 default:
1429 goto end;
1430 }
1431 end:
1432 return applies;
1433 }
1434
1435 /*
1436 * Allocate and initialize an lttng_session_trigger_list which contains
1437 * all triggers that apply to the session named 'session_name'.
1438 *
1439 * No ownership of 'session_name' is assumed by the session trigger list.
1440 * It is the caller's responsability to ensure the session name is alive
1441 * for as long as this list is.
1442 */
1443 static
1444 struct lttng_session_trigger_list *lttng_session_trigger_list_build(
1445 const struct notification_thread_state *state,
1446 const char *session_name)
1447 {
1448 int trigger_count = 0;
1449 struct lttng_session_trigger_list *session_trigger_list = NULL;
1450 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1451 struct cds_lfht_iter iter;
1452
1453 session_trigger_list = lttng_session_trigger_list_create(session_name,
1454 state->session_triggers_ht);
1455
1456 /* Add all triggers applying to the session named 'session_name'. */
1457 cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
1458 node) {
1459 int ret;
1460
1461 if (!trigger_applies_to_session(trigger_ht_element->trigger,
1462 session_name)) {
1463 continue;
1464 }
1465
1466 ret = lttng_session_trigger_list_add(session_trigger_list,
1467 trigger_ht_element->trigger);
1468 if (ret) {
1469 goto error;
1470 }
1471
1472 trigger_count++;
1473 }
1474
1475 DBG("[notification-thread] Found %i triggers that apply to newly created session",
1476 trigger_count);
1477 return session_trigger_list;
1478 error:
1479 lttng_session_trigger_list_destroy(session_trigger_list);
1480 return NULL;
1481 }
1482
1483 static
1484 struct session_info *find_or_create_session_info(
1485 struct notification_thread_state *state,
1486 const char *name, uid_t uid, gid_t gid)
1487 {
1488 struct session_info *session = NULL;
1489 struct cds_lfht_node *node;
1490 struct cds_lfht_iter iter;
1491 struct lttng_session_trigger_list *trigger_list;
1492
1493 rcu_read_lock();
1494 cds_lfht_lookup(state->sessions_ht,
1495 hash_key_str(name, lttng_ht_seed),
1496 match_session,
1497 name,
1498 &iter);
1499 node = cds_lfht_iter_get_node(&iter);
1500 if (node) {
1501 DBG("[notification-thread] Found session info of session \"%s\" (uid = %i, gid = %i)",
1502 name, uid, gid);
1503 session = caa_container_of(node, struct session_info,
1504 sessions_ht_node);
1505 assert(session->uid == uid);
1506 assert(session->gid == gid);
1507 session_info_get(session);
1508 goto end;
1509 }
1510
1511 trigger_list = lttng_session_trigger_list_build(state, name);
1512 if (!trigger_list) {
1513 goto error;
1514 }
1515
1516 session = session_info_create(name, uid, gid, trigger_list,
1517 state->sessions_ht);
1518 if (!session) {
1519 ERR("[notification-thread] Failed to allocation session info for session \"%s\" (uid = %i, gid = %i)",
1520 name, uid, gid);
1521 lttng_session_trigger_list_destroy(trigger_list);
1522 goto error;
1523 }
1524 trigger_list = NULL;
1525
1526 cds_lfht_add(state->sessions_ht, hash_key_str(name, lttng_ht_seed),
1527 &session->sessions_ht_node);
1528 end:
1529 rcu_read_unlock();
1530 return session;
1531 error:
1532 rcu_read_unlock();
1533 session_info_put(session);
1534 return NULL;
1535 }
1536
1537 static
1538 int handle_notification_thread_command_add_channel(
1539 struct notification_thread_state *state,
1540 const char *session_name, uid_t session_uid, gid_t session_gid,
1541 const char *channel_name, enum lttng_domain_type channel_domain,
1542 uint64_t channel_key_int, uint64_t channel_capacity,
1543 enum lttng_error_code *cmd_result)
1544 {
1545 struct cds_list_head trigger_list;
1546 struct channel_info *new_channel_info = NULL;
1547 struct channel_key channel_key = {
1548 .key = channel_key_int,
1549 .domain = channel_domain,
1550 };
1551 struct lttng_channel_trigger_list *channel_trigger_list = NULL;
1552 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1553 int trigger_count = 0;
1554 struct cds_lfht_iter iter;
1555 struct session_info *session_info = NULL;
1556
1557 DBG("[notification-thread] Adding channel %s from session %s, channel key = %" PRIu64 " in %s domain",
1558 channel_name, session_name, channel_key_int,
1559 channel_domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
1560
1561 CDS_INIT_LIST_HEAD(&trigger_list);
1562
1563 session_info = find_or_create_session_info(state, session_name,
1564 session_uid, session_gid);
1565 if (!session_info) {
1566 /* Allocation error or an internal error occurred. */
1567 goto error;
1568 }
1569
1570 new_channel_info = channel_info_create(channel_name, &channel_key,
1571 channel_capacity, session_info);
1572 if (!new_channel_info) {
1573 goto error;
1574 }
1575
1576 rcu_read_lock();
1577 /* Build a list of all triggers applying to the new channel. */
1578 cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
1579 node) {
1580 struct lttng_trigger_list_element *new_element;
1581
1582 if (!trigger_applies_to_channel(trigger_ht_element->trigger,
1583 new_channel_info)) {
1584 continue;
1585 }
1586
1587 new_element = zmalloc(sizeof(*new_element));
1588 if (!new_element) {
1589 rcu_read_unlock();
1590 goto error;
1591 }
1592 CDS_INIT_LIST_HEAD(&new_element->node);
1593 new_element->trigger = trigger_ht_element->trigger;
1594 cds_list_add(&new_element->node, &trigger_list);
1595 trigger_count++;
1596 }
1597 rcu_read_unlock();
1598
1599 DBG("[notification-thread] Found %i triggers that apply to newly added channel",
1600 trigger_count);
1601 channel_trigger_list = zmalloc(sizeof(*channel_trigger_list));
1602 if (!channel_trigger_list) {
1603 goto error;
1604 }
1605 channel_trigger_list->channel_key = new_channel_info->key;
1606 CDS_INIT_LIST_HEAD(&channel_trigger_list->list);
1607 cds_lfht_node_init(&channel_trigger_list->channel_triggers_ht_node);
1608 cds_list_splice(&trigger_list, &channel_trigger_list->list);
1609
1610 rcu_read_lock();
1611 /* Add channel to the channel_ht which owns the channel_infos. */
1612 cds_lfht_add(state->channels_ht,
1613 hash_channel_key(&new_channel_info->key),
1614 &new_channel_info->channels_ht_node);
1615 /*
1616 * Add the list of triggers associated with this channel to the
1617 * channel_triggers_ht.
1618 */
1619 cds_lfht_add(state->channel_triggers_ht,
1620 hash_channel_key(&new_channel_info->key),
1621 &channel_trigger_list->channel_triggers_ht_node);
1622 rcu_read_unlock();
1623 session_info_put(session_info);
1624 *cmd_result = LTTNG_OK;
1625 return 0;
1626 error:
1627 channel_info_destroy(new_channel_info);
1628 session_info_put(session_info);
1629 return 1;
1630 }
1631
1632 static
1633 void free_channel_trigger_list_rcu(struct rcu_head *node)
1634 {
1635 free(caa_container_of(node, struct lttng_channel_trigger_list,
1636 rcu_node));
1637 }
1638
1639 static
1640 void free_channel_state_sample_rcu(struct rcu_head *node)
1641 {
1642 free(caa_container_of(node, struct channel_state_sample,
1643 rcu_node));
1644 }
1645
1646 static
1647 int handle_notification_thread_command_remove_channel(
1648 struct notification_thread_state *state,
1649 uint64_t channel_key, enum lttng_domain_type domain,
1650 enum lttng_error_code *cmd_result)
1651 {
1652 struct cds_lfht_node *node;
1653 struct cds_lfht_iter iter;
1654 struct lttng_channel_trigger_list *trigger_list;
1655 struct lttng_trigger_list_element *trigger_list_element, *tmp;
1656 struct channel_key key = { .key = channel_key, .domain = domain };
1657 struct channel_info *channel_info;
1658
1659 DBG("[notification-thread] Removing channel key = %" PRIu64 " in %s domain",
1660 channel_key, domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
1661
1662 rcu_read_lock();
1663
1664 cds_lfht_lookup(state->channel_triggers_ht,
1665 hash_channel_key(&key),
1666 match_channel_trigger_list,
1667 &key,
1668 &iter);
1669 node = cds_lfht_iter_get_node(&iter);
1670 /*
1671 * There is a severe internal error if we are being asked to remove a
1672 * channel that doesn't exist.
1673 */
1674 if (!node) {
1675 ERR("[notification-thread] Channel being removed is unknown to the notification thread");
1676 goto end;
1677 }
1678
1679 /* Free the list of triggers associated with this channel. */
1680 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
1681 channel_triggers_ht_node);
1682 cds_list_for_each_entry_safe(trigger_list_element, tmp,
1683 &trigger_list->list, node) {
1684 cds_list_del(&trigger_list_element->node);
1685 free(trigger_list_element);
1686 }
1687 cds_lfht_del(state->channel_triggers_ht, node);
1688 call_rcu(&trigger_list->rcu_node, free_channel_trigger_list_rcu);
1689
1690 /* Free sampled channel state. */
1691 cds_lfht_lookup(state->channel_state_ht,
1692 hash_channel_key(&key),
1693 match_channel_state_sample,
1694 &key,
1695 &iter);
1696 node = cds_lfht_iter_get_node(&iter);
1697 /*
1698 * This is expected to be NULL if the channel is destroyed before we
1699 * received a sample.
1700 */
1701 if (node) {
1702 struct channel_state_sample *sample = caa_container_of(node,
1703 struct channel_state_sample,
1704 channel_state_ht_node);
1705
1706 cds_lfht_del(state->channel_state_ht, node);
1707 call_rcu(&sample->rcu_node, free_channel_state_sample_rcu);
1708 }
1709
1710 /* Remove the channel from the channels_ht and free it. */
1711 cds_lfht_lookup(state->channels_ht,
1712 hash_channel_key(&key),
1713 match_channel_info,
1714 &key,
1715 &iter);
1716 node = cds_lfht_iter_get_node(&iter);
1717 assert(node);
1718 channel_info = caa_container_of(node, struct channel_info,
1719 channels_ht_node);
1720 cds_lfht_del(state->channels_ht, node);
1721 channel_info_destroy(channel_info);
1722 end:
1723 rcu_read_unlock();
1724 *cmd_result = LTTNG_OK;
1725 return 0;
1726 }
1727
1728 static
1729 int handle_notification_thread_command_session_rotation(
1730 struct notification_thread_state *state,
1731 enum notification_thread_command_type cmd_type,
1732 const char *session_name, uid_t session_uid, gid_t session_gid,
1733 uint64_t trace_archive_chunk_id,
1734 struct lttng_trace_archive_location *location,
1735 enum lttng_error_code *_cmd_result)
1736 {
1737 int ret = 0;
1738 enum lttng_error_code cmd_result = LTTNG_OK;
1739 struct lttng_session_trigger_list *trigger_list;
1740 struct lttng_trigger_list_element *trigger_list_element;
1741 struct session_info *session_info;
1742
1743 rcu_read_lock();
1744
1745 session_info = find_or_create_session_info(state, session_name,
1746 session_uid, session_gid);
1747 if (!session_info) {
1748 /* Allocation error or an internal error occurred. */
1749 ret = -1;
1750 cmd_result = LTTNG_ERR_NOMEM;
1751 goto end;
1752 }
1753
1754 session_info->rotation.ongoing =
1755 cmd_type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING;
1756 session_info->rotation.id = trace_archive_chunk_id;
1757 trigger_list = get_session_trigger_list(state, session_name);
1758 if (!trigger_list) {
1759 DBG("[notification-thread] No triggers applying to session \"%s\" found",
1760 session_name);
1761 goto end;
1762 }
1763
1764 cds_list_for_each_entry(trigger_list_element, &trigger_list->list,
1765 node) {
1766 const struct lttng_condition *condition;
1767 const struct lttng_action *action;
1768 const struct lttng_trigger *trigger;
1769 struct notification_client_list *client_list;
1770 struct lttng_evaluation *evaluation = NULL;
1771 enum lttng_condition_type condition_type;
1772
1773 trigger = trigger_list_element->trigger;
1774 condition = lttng_trigger_get_const_condition(trigger);
1775 assert(condition);
1776 condition_type = lttng_condition_get_type(condition);
1777
1778 if (condition_type == LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING &&
1779 cmd_type != NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING) {
1780 continue;
1781 } else if (condition_type == LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED &&
1782 cmd_type != NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED) {
1783 continue;
1784 }
1785
1786 action = lttng_trigger_get_const_action(trigger);
1787
1788 /* Notify actions are the only type currently supported. */
1789 assert(lttng_action_get_type_const(action) ==
1790 LTTNG_ACTION_TYPE_NOTIFY);
1791
1792 client_list = get_client_list_from_condition(state, condition);
1793 assert(client_list);
1794
1795 if (cds_list_empty(&client_list->list)) {
1796 /*
1797 * No clients interested in the evaluation's result,
1798 * skip it.
1799 */
1800 continue;
1801 }
1802
1803 if (cmd_type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING) {
1804 evaluation = lttng_evaluation_session_rotation_ongoing_create(
1805 trace_archive_chunk_id);
1806 } else {
1807 evaluation = lttng_evaluation_session_rotation_completed_create(
1808 trace_archive_chunk_id, location);
1809 }
1810
1811 if (!evaluation) {
1812 /* Internal error */
1813 ret = -1;
1814 cmd_result = LTTNG_ERR_UNK;
1815 goto end;
1816 }
1817
1818 /* Dispatch evaluation result to all clients. */
1819 ret = send_evaluation_to_clients(trigger_list_element->trigger,
1820 evaluation, client_list, state,
1821 session_info->uid,
1822 session_info->gid);
1823 lttng_evaluation_destroy(evaluation);
1824 if (caa_unlikely(ret)) {
1825 goto end;
1826 }
1827 }
1828 end:
1829 session_info_put(session_info);
1830 *_cmd_result = cmd_result;
1831 rcu_read_unlock();
1832 return ret;
1833 }
1834
1835 static
1836 int condition_is_supported(struct lttng_condition *condition)
1837 {
1838 int ret;
1839
1840 switch (lttng_condition_get_type(condition)) {
1841 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
1842 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
1843 {
1844 enum lttng_domain_type domain;
1845
1846 ret = lttng_condition_buffer_usage_get_domain_type(condition,
1847 &domain);
1848 if (ret) {
1849 ret = -1;
1850 goto end;
1851 }
1852
1853 if (domain != LTTNG_DOMAIN_KERNEL) {
1854 ret = 1;
1855 goto end;
1856 }
1857
1858 /*
1859 * Older kernel tracers don't expose the API to monitor their
1860 * buffers. Therefore, we reject triggers that require that
1861 * mechanism to be available to be evaluated.
1862 */
1863 ret = kernel_supports_ring_buffer_snapshot_sample_positions(
1864 kernel_tracer_fd);
1865 break;
1866 }
1867 default:
1868 ret = 1;
1869 }
1870 end:
1871 return ret;
1872 }
1873
1874 /* Must be called with RCU read lock held. */
1875 static
1876 int bind_trigger_to_matching_session(const struct lttng_trigger *trigger,
1877 struct notification_thread_state *state)
1878 {
1879 int ret = 0;
1880 const struct lttng_condition *condition;
1881 const char *session_name;
1882 struct lttng_session_trigger_list *trigger_list;
1883
1884 condition = lttng_trigger_get_const_condition(trigger);
1885 switch (lttng_condition_get_type(condition)) {
1886 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
1887 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
1888 {
1889 enum lttng_condition_status status;
1890
1891 status = lttng_condition_session_rotation_get_session_name(
1892 condition, &session_name);
1893 if (status != LTTNG_CONDITION_STATUS_OK) {
1894 ERR("[notification-thread] Failed to bind trigger to session: unable to get 'session_rotation' condition's session name");
1895 ret = -1;
1896 goto end;
1897 }
1898 break;
1899 }
1900 default:
1901 ret = -1;
1902 goto end;
1903 }
1904
1905 trigger_list = get_session_trigger_list(state, session_name);
1906 if (!trigger_list) {
1907 DBG("[notification-thread] Unable to bind trigger applying to session \"%s\" as it is not yet known to the notification system",
1908 session_name);
1909 goto end;
1910
1911 }
1912
1913 DBG("[notification-thread] Newly registered trigger bound to session \"%s\"",
1914 session_name);
1915 ret = lttng_session_trigger_list_add(trigger_list, trigger);
1916 end:
1917 return ret;
1918 }
1919
1920 /* Must be called with RCU read lock held. */
1921 static
1922 int bind_trigger_to_matching_channels(const struct lttng_trigger *trigger,
1923 struct notification_thread_state *state)
1924 {
1925 int ret = 0;
1926 struct cds_lfht_node *node;
1927 struct cds_lfht_iter iter;
1928 struct channel_info *channel;
1929
1930 cds_lfht_for_each_entry(state->channels_ht, &iter, channel,
1931 channels_ht_node) {
1932 struct lttng_trigger_list_element *trigger_list_element;
1933 struct lttng_channel_trigger_list *trigger_list;
1934 struct cds_lfht_iter lookup_iter;
1935
1936 if (!trigger_applies_to_channel(trigger, channel)) {
1937 continue;
1938 }
1939
1940 cds_lfht_lookup(state->channel_triggers_ht,
1941 hash_channel_key(&channel->key),
1942 match_channel_trigger_list,
1943 &channel->key,
1944 &lookup_iter);
1945 node = cds_lfht_iter_get_node(&lookup_iter);
1946 assert(node);
1947 trigger_list = caa_container_of(node,
1948 struct lttng_channel_trigger_list,
1949 channel_triggers_ht_node);
1950
1951 trigger_list_element = zmalloc(sizeof(*trigger_list_element));
1952 if (!trigger_list_element) {
1953 ret = -1;
1954 goto end;
1955 }
1956 CDS_INIT_LIST_HEAD(&trigger_list_element->node);
1957 trigger_list_element->trigger = trigger;
1958 cds_list_add(&trigger_list_element->node, &trigger_list->list);
1959 DBG("[notification-thread] Newly registered trigger bound to channel \"%s\"",
1960 channel->name);
1961 }
1962 end:
1963 return ret;
1964 }
1965
1966 /*
1967 * FIXME A client's credentials are not checked when registering a trigger, nor
1968 * are they stored alongside with the trigger.
1969 *
1970 * The effects of this are benign since:
1971 * - The client will succeed in registering the trigger, as it is valid,
1972 * - The trigger will, internally, be bound to the channel/session,
1973 * - The notifications will not be sent since the client's credentials
1974 * are checked against the channel at that moment.
1975 *
1976 * If this function returns a non-zero value, it means something is
1977 * fundamentally broken and the whole subsystem/thread will be torn down.
1978 *
1979 * If a non-fatal error occurs, just set the cmd_result to the appropriate
1980 * error code.
1981 */
1982 static
1983 int handle_notification_thread_command_register_trigger(
1984 struct notification_thread_state *state,
1985 struct lttng_trigger *trigger,
1986 enum lttng_error_code *cmd_result)
1987 {
1988 int ret = 0;
1989 struct lttng_condition *condition;
1990 struct notification_client *client;
1991 struct notification_client_list *client_list = NULL;
1992 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1993 struct notification_client_list_element *client_list_element, *tmp;
1994 struct cds_lfht_node *node;
1995 struct cds_lfht_iter iter;
1996 bool free_trigger = true;
1997
1998 rcu_read_lock();
1999
2000 condition = lttng_trigger_get_condition(trigger);
2001 assert(condition);
2002
2003 ret = condition_is_supported(condition);
2004 if (ret < 0) {
2005 goto error;
2006 } else if (ret == 0) {
2007 *cmd_result = LTTNG_ERR_NOT_SUPPORTED;
2008 goto error;
2009 } else {
2010 /* Feature is supported, continue. */
2011 ret = 0;
2012 }
2013
2014 trigger_ht_element = zmalloc(sizeof(*trigger_ht_element));
2015 if (!trigger_ht_element) {
2016 ret = -1;
2017 goto error;
2018 }
2019
2020 /* Add trigger to the trigger_ht. */
2021 cds_lfht_node_init(&trigger_ht_element->node);
2022 trigger_ht_element->trigger = trigger;
2023
2024 node = cds_lfht_add_unique(state->triggers_ht,
2025 lttng_condition_hash(condition),
2026 match_condition,
2027 condition,
2028 &trigger_ht_element->node);
2029 if (node != &trigger_ht_element->node) {
2030 /* Not a fatal error, simply report it to the client. */
2031 *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
2032 goto error_free_ht_element;
2033 }
2034
2035 /*
2036 * Ownership of the trigger and of its wrapper was transfered to
2037 * the triggers_ht.
2038 */
2039 trigger_ht_element = NULL;
2040 free_trigger = false;
2041
2042 /*
2043 * The rest only applies to triggers that have a "notify" action.
2044 * It is not skipped as this is the only action type currently
2045 * supported.
2046 */
2047 client_list = zmalloc(sizeof(*client_list));
2048 if (!client_list) {
2049 ret = -1;
2050 goto error_free_ht_element;
2051 }
2052 cds_lfht_node_init(&client_list->notification_trigger_ht_node);
2053 CDS_INIT_LIST_HEAD(&client_list->list);
2054 client_list->trigger = trigger;
2055
2056 /* Build a list of clients to which this new trigger applies. */
2057 cds_lfht_for_each_entry(state->client_socket_ht, &iter, client,
2058 client_socket_ht_node) {
2059 if (!trigger_applies_to_client(trigger, client)) {
2060 continue;
2061 }
2062
2063 client_list_element = zmalloc(sizeof(*client_list_element));
2064 if (!client_list_element) {
2065 ret = -1;
2066 goto error_free_client_list;
2067 }
2068 CDS_INIT_LIST_HEAD(&client_list_element->node);
2069 client_list_element->client = client;
2070 cds_list_add(&client_list_element->node, &client_list->list);
2071 }
2072
2073 cds_lfht_add(state->notification_trigger_clients_ht,
2074 lttng_condition_hash(condition),
2075 &client_list->notification_trigger_ht_node);
2076
2077 switch (get_condition_binding_object(condition)) {
2078 case LTTNG_OBJECT_TYPE_SESSION:
2079 /* Add the trigger to the list if it matches a known session. */
2080 ret = bind_trigger_to_matching_session(trigger, state);
2081 if (ret) {
2082 goto error_free_client_list;
2083 }
2084 break;
2085 case LTTNG_OBJECT_TYPE_CHANNEL:
2086 /*
2087 * Add the trigger to list of triggers bound to the channels
2088 * currently known.
2089 */
2090 ret = bind_trigger_to_matching_channels(trigger, state);
2091 if (ret) {
2092 goto error_free_client_list;
2093 }
2094 break;
2095 case LTTNG_OBJECT_TYPE_NONE:
2096 break;
2097 default:
2098 ERR("[notification-thread] Unknown object type on which to bind a newly registered trigger was encountered");
2099 ret = -1;
2100 goto error_free_client_list;
2101 }
2102
2103 /*
2104 * Since there is nothing preventing clients from subscribing to a
2105 * condition before the corresponding trigger is registered, we have
2106 * to evaluate this new condition right away.
2107 *
2108 * At some point, we were waiting for the next "evaluation" (e.g. on
2109 * reception of a channel sample) to evaluate this new condition, but
2110 * that was broken.
2111 *
2112 * The reason it was broken is that waiting for the next sample
2113 * does not allow us to properly handle transitions for edge-triggered
2114 * conditions.
2115 *
2116 * Consider this example: when we handle a new channel sample, we
2117 * evaluate each conditions twice: once with the previous state, and
2118 * again with the newest state. We then use those two results to
2119 * determine whether a state change happened: a condition was false and
2120 * became true. If a state change happened, we have to notify clients.
2121 *
2122 * Now, if a client subscribes to a given notification and registers
2123 * a trigger *after* that subscription, we have to make sure the
2124 * condition is evaluated at this point while considering only the
2125 * current state. Otherwise, the next evaluation cycle may only see
2126 * that the evaluations remain the same (true for samples n-1 and n) and
2127 * the client will never know that the condition has been met.
2128 */
2129 cds_list_for_each_entry_safe(client_list_element, tmp,
2130 &client_list->list, node) {
2131 ret = evaluate_condition_for_client(trigger, condition,
2132 client_list_element->client, state);
2133 if (ret) {
2134 goto error_free_client_list;
2135 }
2136 }
2137
2138 /*
2139 * Client list ownership transferred to the
2140 * notification_trigger_clients_ht.
2141 */
2142 client_list = NULL;
2143
2144 *cmd_result = LTTNG_OK;
2145 error_free_client_list:
2146 if (client_list) {
2147 cds_list_for_each_entry_safe(client_list_element, tmp,
2148 &client_list->list, node) {
2149 free(client_list_element);
2150 }
2151 free(client_list);
2152 }
2153 error_free_ht_element:
2154 free(trigger_ht_element);
2155 error:
2156 if (free_trigger) {
2157 struct lttng_action *action = lttng_trigger_get_action(trigger);
2158
2159 lttng_condition_destroy(condition);
2160 lttng_action_destroy(action);
2161 lttng_trigger_destroy(trigger);
2162 }
2163 rcu_read_unlock();
2164 return ret;
2165 }
2166
2167 static
2168 void free_notification_client_list_rcu(struct rcu_head *node)
2169 {
2170 free(caa_container_of(node, struct notification_client_list,
2171 rcu_node));
2172 }
2173
2174 static
2175 void free_lttng_trigger_ht_element_rcu(struct rcu_head *node)
2176 {
2177 free(caa_container_of(node, struct lttng_trigger_ht_element,
2178 rcu_node));
2179 }
2180
2181 static
2182 int handle_notification_thread_command_unregister_trigger(
2183 struct notification_thread_state *state,
2184 struct lttng_trigger *trigger,
2185 enum lttng_error_code *_cmd_reply)
2186 {
2187 struct cds_lfht_iter iter;
2188 struct cds_lfht_node *triggers_ht_node;
2189 struct lttng_channel_trigger_list *trigger_list;
2190 struct notification_client_list *client_list;
2191 struct notification_client_list_element *client_list_element, *tmp;
2192 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
2193 struct lttng_condition *condition = lttng_trigger_get_condition(
2194 trigger);
2195 struct lttng_action *action;
2196 enum lttng_error_code cmd_reply;
2197
2198 rcu_read_lock();
2199
2200 cds_lfht_lookup(state->triggers_ht,
2201 lttng_condition_hash(condition),
2202 match_condition,
2203 condition,
2204 &iter);
2205 triggers_ht_node = cds_lfht_iter_get_node(&iter);
2206 if (!triggers_ht_node) {
2207 cmd_reply = LTTNG_ERR_TRIGGER_NOT_FOUND;
2208 goto end;
2209 } else {
2210 cmd_reply = LTTNG_OK;
2211 }
2212
2213 /* Remove trigger from channel_triggers_ht. */
2214 cds_lfht_for_each_entry(state->channel_triggers_ht, &iter, trigger_list,
2215 channel_triggers_ht_node) {
2216 struct lttng_trigger_list_element *trigger_element, *tmp;
2217
2218 cds_list_for_each_entry_safe(trigger_element, tmp,
2219 &trigger_list->list, node) {
2220 const struct lttng_condition *current_condition =
2221 lttng_trigger_get_const_condition(
2222 trigger_element->trigger);
2223
2224 assert(current_condition);
2225 if (!lttng_condition_is_equal(condition,
2226 current_condition)) {
2227 continue;
2228 }
2229
2230 DBG("[notification-thread] Removed trigger from channel_triggers_ht");
2231 cds_list_del(&trigger_element->node);
2232 /* A trigger can only appear once per channel */
2233 break;
2234 }
2235 }
2236
2237 /*
2238 * Remove and release the client list from
2239 * notification_trigger_clients_ht.
2240 */
2241 client_list = get_client_list_from_condition(state, condition);
2242 assert(client_list);
2243
2244 cds_list_for_each_entry_safe(client_list_element, tmp,
2245 &client_list->list, node) {
2246 free(client_list_element);
2247 }
2248 cds_lfht_del(state->notification_trigger_clients_ht,
2249 &client_list->notification_trigger_ht_node);
2250 call_rcu(&client_list->rcu_node, free_notification_client_list_rcu);
2251
2252 /* Remove trigger from triggers_ht. */
2253 trigger_ht_element = caa_container_of(triggers_ht_node,
2254 struct lttng_trigger_ht_element, node);
2255 cds_lfht_del(state->triggers_ht, triggers_ht_node);
2256
2257 condition = lttng_trigger_get_condition(trigger_ht_element->trigger);
2258 lttng_condition_destroy(condition);
2259 action = lttng_trigger_get_action(trigger_ht_element->trigger);
2260 lttng_action_destroy(action);
2261 lttng_trigger_destroy(trigger_ht_element->trigger);
2262 call_rcu(&trigger_ht_element->rcu_node, free_lttng_trigger_ht_element_rcu);
2263 end:
2264 rcu_read_unlock();
2265 if (_cmd_reply) {
2266 *_cmd_reply = cmd_reply;
2267 }
2268 return 0;
2269 }
2270
2271 /* Returns 0 on success, 1 on exit requested, negative value on error. */
2272 int handle_notification_thread_command(
2273 struct notification_thread_handle *handle,
2274 struct notification_thread_state *state)
2275 {
2276 int ret;
2277 uint64_t counter;
2278 struct notification_thread_command *cmd;
2279
2280 /* Read the event pipe to put it back into a quiescent state. */
2281 ret = lttng_read(lttng_pipe_get_readfd(handle->cmd_queue.event_pipe), &counter,
2282 sizeof(counter));
2283 if (ret != sizeof(counter)) {
2284 goto error;
2285 }
2286
2287 pthread_mutex_lock(&handle->cmd_queue.lock);
2288 cmd = cds_list_first_entry(&handle->cmd_queue.list,
2289 struct notification_thread_command, cmd_list_node);
2290 switch (cmd->type) {
2291 case NOTIFICATION_COMMAND_TYPE_REGISTER_TRIGGER:
2292 DBG("[notification-thread] Received register trigger command");
2293 ret = handle_notification_thread_command_register_trigger(
2294 state, cmd->parameters.trigger,
2295 &cmd->reply_code);
2296 break;
2297 case NOTIFICATION_COMMAND_TYPE_UNREGISTER_TRIGGER:
2298 DBG("[notification-thread] Received unregister trigger command");
2299 ret = handle_notification_thread_command_unregister_trigger(
2300 state, cmd->parameters.trigger,
2301 &cmd->reply_code);
2302 break;
2303 case NOTIFICATION_COMMAND_TYPE_ADD_CHANNEL:
2304 DBG("[notification-thread] Received add channel command");
2305 ret = handle_notification_thread_command_add_channel(
2306 state,
2307 cmd->parameters.add_channel.session.name,
2308 cmd->parameters.add_channel.session.uid,
2309 cmd->parameters.add_channel.session.gid,
2310 cmd->parameters.add_channel.channel.name,
2311 cmd->parameters.add_channel.channel.domain,
2312 cmd->parameters.add_channel.channel.key,
2313 cmd->parameters.add_channel.channel.capacity,
2314 &cmd->reply_code);
2315 break;
2316 case NOTIFICATION_COMMAND_TYPE_REMOVE_CHANNEL:
2317 DBG("[notification-thread] Received remove channel command");
2318 ret = handle_notification_thread_command_remove_channel(
2319 state, cmd->parameters.remove_channel.key,
2320 cmd->parameters.remove_channel.domain,
2321 &cmd->reply_code);
2322 break;
2323 case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING:
2324 case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED:
2325 DBG("[notification-thread] Received session rotation %s command",
2326 cmd->type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING ?
2327 "ongoing" : "completed");
2328 ret = handle_notification_thread_command_session_rotation(
2329 state,
2330 cmd->type,
2331 cmd->parameters.session_rotation.session_name,
2332 cmd->parameters.session_rotation.uid,
2333 cmd->parameters.session_rotation.gid,
2334 cmd->parameters.session_rotation.trace_archive_chunk_id,
2335 cmd->parameters.session_rotation.location,
2336 &cmd->reply_code);
2337 break;
2338 case NOTIFICATION_COMMAND_TYPE_QUIT:
2339 DBG("[notification-thread] Received quit command");
2340 cmd->reply_code = LTTNG_OK;
2341 ret = 1;
2342 goto end;
2343 default:
2344 ERR("[notification-thread] Unknown internal command received");
2345 goto error_unlock;
2346 }
2347
2348 if (ret) {
2349 goto error_unlock;
2350 }
2351 end:
2352 cds_list_del(&cmd->cmd_list_node);
2353 lttng_waiter_wake_up(&cmd->reply_waiter);
2354 pthread_mutex_unlock(&handle->cmd_queue.lock);
2355 return ret;
2356 error_unlock:
2357 /* Wake-up and return a fatal error to the calling thread. */
2358 lttng_waiter_wake_up(&cmd->reply_waiter);
2359 pthread_mutex_unlock(&handle->cmd_queue.lock);
2360 cmd->reply_code = LTTNG_ERR_FATAL;
2361 error:
2362 /* Indicate a fatal error to the caller. */
2363 return -1;
2364 }
2365
2366 static
2367 unsigned long hash_client_socket(int socket)
2368 {
2369 return hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed);
2370 }
2371
2372 static
2373 int socket_set_non_blocking(int socket)
2374 {
2375 int ret, flags;
2376
2377 /* Set the pipe as non-blocking. */
2378 ret = fcntl(socket, F_GETFL, 0);
2379 if (ret == -1) {
2380 PERROR("fcntl get socket flags");
2381 goto end;
2382 }
2383 flags = ret;
2384
2385 ret = fcntl(socket, F_SETFL, flags | O_NONBLOCK);
2386 if (ret == -1) {
2387 PERROR("fcntl set O_NONBLOCK socket flag");
2388 goto end;
2389 }
2390 DBG("Client socket (fd = %i) set as non-blocking", socket);
2391 end:
2392 return ret;
2393 }
2394
2395 static
2396 int client_reset_inbound_state(struct notification_client *client)
2397 {
2398 int ret;
2399
2400 ret = lttng_dynamic_buffer_set_size(
2401 &client->communication.inbound.buffer, 0);
2402 assert(!ret);
2403
2404 client->communication.inbound.bytes_to_receive =
2405 sizeof(struct lttng_notification_channel_message);
2406 client->communication.inbound.msg_type =
2407 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN;
2408 LTTNG_SOCK_SET_UID_CRED(&client->communication.inbound.creds, -1);
2409 LTTNG_SOCK_SET_GID_CRED(&client->communication.inbound.creds, -1);
2410 ret = lttng_dynamic_buffer_set_size(
2411 &client->communication.inbound.buffer,
2412 client->communication.inbound.bytes_to_receive);
2413 return ret;
2414 }
2415
2416 int handle_notification_thread_client_connect(
2417 struct notification_thread_state *state)
2418 {
2419 int ret;
2420 struct notification_client *client;
2421
2422 DBG("[notification-thread] Handling new notification channel client connection");
2423
2424 client = zmalloc(sizeof(*client));
2425 if (!client) {
2426 /* Fatal error. */
2427 ret = -1;
2428 goto error;
2429 }
2430 CDS_INIT_LIST_HEAD(&client->condition_list);
2431 lttng_dynamic_buffer_init(&client->communication.inbound.buffer);
2432 lttng_dynamic_buffer_init(&client->communication.outbound.buffer);
2433 client->communication.inbound.expect_creds = true;
2434 ret = client_reset_inbound_state(client);
2435 if (ret) {
2436 ERR("[notification-thread] Failed to reset client communication's inbound state");
2437 ret = 0;
2438 goto error;
2439 }
2440
2441 ret = lttcomm_accept_unix_sock(state->notification_channel_socket);
2442 if (ret < 0) {
2443 ERR("[notification-thread] Failed to accept new notification channel client connection");
2444 ret = 0;
2445 goto error;
2446 }
2447
2448 client->socket = ret;
2449
2450 ret = socket_set_non_blocking(client->socket);
2451 if (ret) {
2452 ERR("[notification-thread] Failed to set new notification channel client connection socket as non-blocking");
2453 goto error;
2454 }
2455
2456 ret = lttcomm_setsockopt_creds_unix_sock(client->socket);
2457 if (ret < 0) {
2458 ERR("[notification-thread] Failed to set socket options on new notification channel client socket");
2459 ret = 0;
2460 goto error;
2461 }
2462
2463 ret = lttng_poll_add(&state->events, client->socket,
2464 LPOLLIN | LPOLLERR |
2465 LPOLLHUP | LPOLLRDHUP);
2466 if (ret < 0) {
2467 ERR("[notification-thread] Failed to add notification channel client socket to poll set");
2468 ret = 0;
2469 goto error;
2470 }
2471 DBG("[notification-thread] Added new notification channel client socket (%i) to poll set",
2472 client->socket);
2473
2474 rcu_read_lock();
2475 cds_lfht_add(state->client_socket_ht,
2476 hash_client_socket(client->socket),
2477 &client->client_socket_ht_node);
2478 rcu_read_unlock();
2479
2480 return ret;
2481 error:
2482 notification_client_destroy(client, state);
2483 return ret;
2484 }
2485
2486 int handle_notification_thread_client_disconnect(
2487 int client_socket,
2488 struct notification_thread_state *state)
2489 {
2490 int ret = 0;
2491 struct notification_client *client;
2492
2493 rcu_read_lock();
2494 DBG("[notification-thread] Closing client connection (socket fd = %i)",
2495 client_socket);
2496 client = get_client_from_socket(client_socket, state);
2497 if (!client) {
2498 /* Internal state corruption, fatal error. */
2499 ERR("[notification-thread] Unable to find client (socket fd = %i)",
2500 client_socket);
2501 ret = -1;
2502 goto end;
2503 }
2504
2505 ret = lttng_poll_del(&state->events, client_socket);
2506 if (ret) {
2507 ERR("[notification-thread] Failed to remove client socket from poll set");
2508 }
2509 cds_lfht_del(state->client_socket_ht,
2510 &client->client_socket_ht_node);
2511 notification_client_destroy(client, state);
2512 end:
2513 rcu_read_unlock();
2514 return ret;
2515 }
2516
2517 int handle_notification_thread_client_disconnect_all(
2518 struct notification_thread_state *state)
2519 {
2520 struct cds_lfht_iter iter;
2521 struct notification_client *client;
2522 bool error_encoutered = false;
2523
2524 rcu_read_lock();
2525 DBG("[notification-thread] Closing all client connections");
2526 cds_lfht_for_each_entry(state->client_socket_ht, &iter, client,
2527 client_socket_ht_node) {
2528 int ret;
2529
2530 ret = handle_notification_thread_client_disconnect(
2531 client->socket, state);
2532 if (ret) {
2533 error_encoutered = true;
2534 }
2535 }
2536 rcu_read_unlock();
2537 return error_encoutered ? 1 : 0;
2538 }
2539
2540 int handle_notification_thread_trigger_unregister_all(
2541 struct notification_thread_state *state)
2542 {
2543 bool error_occurred = false;
2544 struct cds_lfht_iter iter;
2545 struct lttng_trigger_ht_element *trigger_ht_element;
2546
2547 cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
2548 node) {
2549 int ret = handle_notification_thread_command_unregister_trigger(
2550 state, trigger_ht_element->trigger, NULL);
2551 if (ret) {
2552 error_occurred = true;
2553 }
2554 }
2555 return error_occurred ? -1 : 0;
2556 }
2557
2558 static
2559 int client_flush_outgoing_queue(struct notification_client *client,
2560 struct notification_thread_state *state)
2561 {
2562 ssize_t ret;
2563 size_t to_send_count;
2564
2565 assert(client->communication.outbound.buffer.size != 0);
2566 to_send_count = client->communication.outbound.buffer.size;
2567 DBG("[notification-thread] Flushing client (socket fd = %i) outgoing queue",
2568 client->socket);
2569
2570 ret = lttcomm_send_unix_sock_non_block(client->socket,
2571 client->communication.outbound.buffer.data,
2572 to_send_count);
2573 if ((ret < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) ||
2574 (ret > 0 && ret < to_send_count)) {
2575 DBG("[notification-thread] Client (socket fd = %i) outgoing queue could not be completely flushed",
2576 client->socket);
2577 to_send_count -= max(ret, 0);
2578
2579 memcpy(client->communication.outbound.buffer.data,
2580 client->communication.outbound.buffer.data +
2581 client->communication.outbound.buffer.size - to_send_count,
2582 to_send_count);
2583 ret = lttng_dynamic_buffer_set_size(
2584 &client->communication.outbound.buffer,
2585 to_send_count);
2586 if (ret) {
2587 goto error;
2588 }
2589
2590 /*
2591 * We want to be notified whenever there is buffer space
2592 * available to send the rest of the payload.
2593 */
2594 ret = lttng_poll_mod(&state->events, client->socket,
2595 CLIENT_POLL_MASK_IN_OUT);
2596 if (ret) {
2597 goto error;
2598 }
2599 } else if (ret < 0) {
2600 /* Generic error, disconnect the client. */
2601 ERR("[notification-thread] Failed to send flush outgoing queue, disconnecting client (socket fd = %i)",
2602 client->socket);
2603 ret = handle_notification_thread_client_disconnect(
2604 client->socket, state);
2605 if (ret) {
2606 goto error;
2607 }
2608 } else {
2609 /* No error and flushed the queue completely. */
2610 ret = lttng_dynamic_buffer_set_size(
2611 &client->communication.outbound.buffer, 0);
2612 if (ret) {
2613 goto error;
2614 }
2615 ret = lttng_poll_mod(&state->events, client->socket,
2616 CLIENT_POLL_MASK_IN);
2617 if (ret) {
2618 goto error;
2619 }
2620
2621 client->communication.outbound.queued_command_reply = false;
2622 client->communication.outbound.dropped_notification = false;
2623 }
2624
2625 return 0;
2626 error:
2627 return -1;
2628 }
2629
2630 static
2631 int client_send_command_reply(struct notification_client *client,
2632 struct notification_thread_state *state,
2633 enum lttng_notification_channel_status status)
2634 {
2635 int ret;
2636 struct lttng_notification_channel_command_reply reply = {
2637 .status = (int8_t) status,
2638 };
2639 struct lttng_notification_channel_message msg = {
2640 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY,
2641 .size = sizeof(reply),
2642 };
2643 char buffer[sizeof(msg) + sizeof(reply)];
2644
2645 if (client->communication.outbound.queued_command_reply) {
2646 /* Protocol error. */
2647 goto error;
2648 }
2649
2650 memcpy(buffer, &msg, sizeof(msg));
2651 memcpy(buffer + sizeof(msg), &reply, sizeof(reply));
2652 DBG("[notification-thread] Send command reply (%i)", (int) status);
2653
2654 /* Enqueue buffer to outgoing queue and flush it. */
2655 ret = lttng_dynamic_buffer_append(
2656 &client->communication.outbound.buffer,
2657 buffer, sizeof(buffer));
2658 if (ret) {
2659 goto error;
2660 }
2661
2662 ret = client_flush_outgoing_queue(client, state);
2663 if (ret) {
2664 goto error;
2665 }
2666
2667 if (client->communication.outbound.buffer.size != 0) {
2668 /* Queue could not be emptied. */
2669 client->communication.outbound.queued_command_reply = true;
2670 }
2671
2672 return 0;
2673 error:
2674 return -1;
2675 }
2676
2677 static
2678 int client_dispatch_message(struct notification_client *client,
2679 struct notification_thread_state *state)
2680 {
2681 int ret = 0;
2682
2683 if (client->communication.inbound.msg_type !=
2684 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE &&
2685 client->communication.inbound.msg_type !=
2686 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN &&
2687 !client->validated) {
2688 WARN("[notification-thread] client attempted a command before handshake");
2689 ret = -1;
2690 goto end;
2691 }
2692
2693 switch (client->communication.inbound.msg_type) {
2694 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN:
2695 {
2696 /*
2697 * Receiving message header. The function will be called again
2698 * once the rest of the message as been received and can be
2699 * interpreted.
2700 */
2701 const struct lttng_notification_channel_message *msg;
2702
2703 assert(sizeof(*msg) ==
2704 client->communication.inbound.buffer.size);
2705 msg = (const struct lttng_notification_channel_message *)
2706 client->communication.inbound.buffer.data;
2707
2708 if (msg->size == 0 || msg->size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) {
2709 ERR("[notification-thread] Invalid notification channel message: length = %u", msg->size);
2710 ret = -1;
2711 goto end;
2712 }
2713
2714 switch (msg->type) {
2715 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE:
2716 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE:
2717 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE:
2718 break;
2719 default:
2720 ret = -1;
2721 ERR("[notification-thread] Invalid notification channel message: unexpected message type");
2722 goto end;
2723 }
2724
2725 client->communication.inbound.bytes_to_receive = msg->size;
2726 client->communication.inbound.msg_type =
2727 (enum lttng_notification_channel_message_type) msg->type;
2728 ret = lttng_dynamic_buffer_set_size(
2729 &client->communication.inbound.buffer, msg->size);
2730 if (ret) {
2731 goto end;
2732 }
2733 break;
2734 }
2735 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE:
2736 {
2737 struct lttng_notification_channel_command_handshake *handshake_client;
2738 struct lttng_notification_channel_command_handshake handshake_reply = {
2739 .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR,
2740 .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR,
2741 };
2742 struct lttng_notification_channel_message msg_header = {
2743 .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE,
2744 .size = sizeof(handshake_reply),
2745 };
2746 enum lttng_notification_channel_status status =
2747 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
2748 char send_buffer[sizeof(msg_header) + sizeof(handshake_reply)];
2749
2750 memcpy(send_buffer, &msg_header, sizeof(msg_header));
2751 memcpy(send_buffer + sizeof(msg_header), &handshake_reply,
2752 sizeof(handshake_reply));
2753
2754 handshake_client =
2755 (struct lttng_notification_channel_command_handshake *)
2756 client->communication.inbound.buffer.data;
2757 client->major = handshake_client->major;
2758 client->minor = handshake_client->minor;
2759 if (!client->communication.inbound.creds_received) {
2760 ERR("[notification-thread] No credentials received from client");
2761 ret = -1;
2762 goto end;
2763 }
2764
2765 client->uid = LTTNG_SOCK_GET_UID_CRED(
2766 &client->communication.inbound.creds);
2767 client->gid = LTTNG_SOCK_GET_GID_CRED(
2768 &client->communication.inbound.creds);
2769 DBG("[notification-thread] Received handshake from client (uid = %u, gid = %u) with version %i.%i",
2770 client->uid, client->gid, (int) client->major,
2771 (int) client->minor);
2772
2773 if (handshake_client->major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) {
2774 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNSUPPORTED_VERSION;
2775 }
2776
2777 ret = lttng_dynamic_buffer_append(&client->communication.outbound.buffer,
2778 send_buffer, sizeof(send_buffer));
2779 if (ret) {
2780 ERR("[notification-thread] Failed to send protocol version to notification channel client");
2781 goto end;
2782 }
2783
2784 ret = client_flush_outgoing_queue(client, state);
2785 if (ret) {
2786 goto end;
2787 }
2788
2789 ret = client_send_command_reply(client, state, status);
2790 if (ret) {
2791 ERR("[notification-thread] Failed to send reply to notification channel client");
2792 goto end;
2793 }
2794
2795 /* Set reception state to receive the next message header. */
2796 ret = client_reset_inbound_state(client);
2797 if (ret) {
2798 ERR("[notification-thread] Failed to reset client communication's inbound state");
2799 goto end;
2800 }
2801 client->validated = true;
2802 break;
2803 }
2804 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE:
2805 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE:
2806 {
2807 struct lttng_condition *condition;
2808 enum lttng_notification_channel_status status =
2809 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
2810 const struct lttng_buffer_view condition_view =
2811 lttng_buffer_view_from_dynamic_buffer(
2812 &client->communication.inbound.buffer,
2813 0, -1);
2814 size_t expected_condition_size =
2815 client->communication.inbound.buffer.size;
2816
2817 ret = lttng_condition_create_from_buffer(&condition_view,
2818 &condition);
2819 if (ret != expected_condition_size) {
2820 ERR("[notification-thread] Malformed condition received from client");
2821 goto end;
2822 }
2823
2824 if (client->communication.inbound.msg_type ==
2825 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE) {
2826 ret = notification_thread_client_subscribe(client,
2827 condition, state, &status);
2828 } else {
2829 ret = notification_thread_client_unsubscribe(client,
2830 condition, state, &status);
2831 }
2832 if (ret) {
2833 goto end;
2834 }
2835
2836 ret = client_send_command_reply(client, state, status);
2837 if (ret) {
2838 ERR("[notification-thread] Failed to send reply to notification channel client");
2839 goto end;
2840 }
2841
2842 /* Set reception state to receive the next message header. */
2843 ret = client_reset_inbound_state(client);
2844 if (ret) {
2845 ERR("[notification-thread] Failed to reset client communication's inbound state");
2846 goto end;
2847 }
2848 break;
2849 }
2850 default:
2851 abort();
2852 }
2853 end:
2854 return ret;
2855 }
2856
2857 /* Incoming data from client. */
2858 int handle_notification_thread_client_in(
2859 struct notification_thread_state *state, int socket)
2860 {
2861 int ret = 0;
2862 struct notification_client *client;
2863 ssize_t recv_ret;
2864 size_t offset;
2865
2866 client = get_client_from_socket(socket, state);
2867 if (!client) {
2868 /* Internal error, abort. */
2869 ret = -1;
2870 goto end;
2871 }
2872
2873 offset = client->communication.inbound.buffer.size -
2874 client->communication.inbound.bytes_to_receive;
2875 if (client->communication.inbound.expect_creds) {
2876 recv_ret = lttcomm_recv_creds_unix_sock(socket,
2877 client->communication.inbound.buffer.data + offset,
2878 client->communication.inbound.bytes_to_receive,
2879 &client->communication.inbound.creds);
2880 if (recv_ret > 0) {
2881 client->communication.inbound.expect_creds = false;
2882 client->communication.inbound.creds_received = true;
2883 }
2884 } else {
2885 recv_ret = lttcomm_recv_unix_sock_non_block(socket,
2886 client->communication.inbound.buffer.data + offset,
2887 client->communication.inbound.bytes_to_receive);
2888 }
2889 if (recv_ret < 0) {
2890 goto error_disconnect_client;
2891 }
2892
2893 client->communication.inbound.bytes_to_receive -= recv_ret;
2894 if (client->communication.inbound.bytes_to_receive == 0) {
2895 ret = client_dispatch_message(client, state);
2896 if (ret) {
2897 /*
2898 * Only returns an error if this client must be
2899 * disconnected.
2900 */
2901 goto error_disconnect_client;
2902 }
2903 } else {
2904 goto end;
2905 }
2906 end:
2907 return ret;
2908 error_disconnect_client:
2909 ret = handle_notification_thread_client_disconnect(socket, state);
2910 return ret;
2911 }
2912
2913 /* Client ready to receive outgoing data. */
2914 int handle_notification_thread_client_out(
2915 struct notification_thread_state *state, int socket)
2916 {
2917 int ret;
2918 struct notification_client *client;
2919
2920 client = get_client_from_socket(socket, state);
2921 if (!client) {
2922 /* Internal error, abort. */
2923 ret = -1;
2924 goto end;
2925 }
2926
2927 ret = client_flush_outgoing_queue(client, state);
2928 if (ret) {
2929 goto end;
2930 }
2931 end:
2932 return ret;
2933 }
2934
2935 static
2936 bool evaluate_buffer_usage_condition(const struct lttng_condition *condition,
2937 const struct channel_state_sample *sample,
2938 uint64_t buffer_capacity)
2939 {
2940 bool result = false;
2941 uint64_t threshold;
2942 enum lttng_condition_type condition_type;
2943 const struct lttng_condition_buffer_usage *use_condition = container_of(
2944 condition, struct lttng_condition_buffer_usage,
2945 parent);
2946
2947 if (use_condition->threshold_bytes.set) {
2948 threshold = use_condition->threshold_bytes.value;
2949 } else {
2950 /*
2951 * Threshold was expressed as a ratio.
2952 *
2953 * TODO the threshold (in bytes) of conditions expressed
2954 * as a ratio of total buffer size could be cached to
2955 * forego this double-multiplication or it could be performed
2956 * as fixed-point math.
2957 *
2958 * Note that caching should accomodate the case where the
2959 * condition applies to multiple channels (i.e. don't assume
2960 * that all channels matching my_chann* have the same size...)
2961 */
2962 threshold = (uint64_t) (use_condition->threshold_ratio.value *
2963 (double) buffer_capacity);
2964 }
2965
2966 condition_type = lttng_condition_get_type(condition);
2967 if (condition_type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW) {
2968 DBG("[notification-thread] Low buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
2969 threshold, sample->highest_usage);
2970
2971 /*
2972 * The low condition should only be triggered once _all_ of the
2973 * streams in a channel have gone below the "low" threshold.
2974 */
2975 if (sample->highest_usage <= threshold) {
2976 result = true;
2977 }
2978 } else {
2979 DBG("[notification-thread] High buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
2980 threshold, sample->highest_usage);
2981
2982 /*
2983 * For high buffer usage scenarios, we want to trigger whenever
2984 * _any_ of the streams has reached the "high" threshold.
2985 */
2986 if (sample->highest_usage >= threshold) {
2987 result = true;
2988 }
2989 }
2990
2991 return result;
2992 }
2993
2994 static
2995 bool evaluate_session_consumed_size_condition(
2996 const struct lttng_condition *condition,
2997 uint64_t session_consumed_size)
2998 {
2999 uint64_t threshold;
3000 const struct lttng_condition_session_consumed_size *size_condition =
3001 container_of(condition,
3002 struct lttng_condition_session_consumed_size,
3003 parent);
3004
3005 threshold = size_condition->consumed_threshold_bytes.value;
3006 DBG("[notification-thread] Session consumed size condition being evaluated: threshold = %" PRIu64 ", current size = %" PRIu64,
3007 threshold, session_consumed_size);
3008 return session_consumed_size >= threshold;
3009 }
3010
3011 static
3012 int evaluate_buffer_condition(const struct lttng_condition *condition,
3013 struct lttng_evaluation **evaluation,
3014 const struct notification_thread_state *state,
3015 const struct channel_state_sample *previous_sample,
3016 const struct channel_state_sample *latest_sample,
3017 uint64_t previous_session_consumed_total,
3018 uint64_t latest_session_consumed_total,
3019 struct channel_info *channel_info)
3020 {
3021 int ret = 0;
3022 enum lttng_condition_type condition_type;
3023 const bool previous_sample_available = !!previous_sample;
3024 bool previous_sample_result = false;
3025 bool latest_sample_result;
3026
3027 condition_type = lttng_condition_get_type(condition);
3028
3029 switch (condition_type) {
3030 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
3031 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
3032 if (caa_likely(previous_sample_available)) {
3033 previous_sample_result =
3034 evaluate_buffer_usage_condition(condition,
3035 previous_sample, channel_info->capacity);
3036 }
3037 latest_sample_result = evaluate_buffer_usage_condition(
3038 condition, latest_sample,
3039 channel_info->capacity);
3040 break;
3041 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
3042 if (caa_likely(previous_sample_available)) {
3043 previous_sample_result =
3044 evaluate_session_consumed_size_condition(
3045 condition,
3046 previous_session_consumed_total);
3047 }
3048 latest_sample_result =
3049 evaluate_session_consumed_size_condition(
3050 condition,
3051 latest_session_consumed_total);
3052 break;
3053 default:
3054 /* Unknown condition type; internal error. */
3055 abort();
3056 }
3057
3058 if (!latest_sample_result ||
3059 (previous_sample_result == latest_sample_result)) {
3060 /*
3061 * Only trigger on a condition evaluation transition.
3062 *
3063 * NOTE: This edge-triggered logic may not be appropriate for
3064 * future condition types.
3065 */
3066 goto end;
3067 }
3068
3069 if (!evaluation || !latest_sample_result) {
3070 goto end;
3071 }
3072
3073 switch (condition_type) {
3074 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
3075 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
3076 *evaluation = lttng_evaluation_buffer_usage_create(
3077 condition_type,
3078 latest_sample->highest_usage,
3079 channel_info->capacity);
3080 break;
3081 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
3082 *evaluation = lttng_evaluation_session_consumed_size_create(
3083 latest_session_consumed_total);
3084 break;
3085 default:
3086 abort();
3087 }
3088
3089 if (!*evaluation) {
3090 ret = -1;
3091 goto end;
3092 }
3093 end:
3094 return ret;
3095 }
3096
3097 static
3098 int client_enqueue_dropped_notification(struct notification_client *client,
3099 struct notification_thread_state *state)
3100 {
3101 int ret;
3102 struct lttng_notification_channel_message msg = {
3103 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED,
3104 .size = 0,
3105 };
3106
3107 ret = lttng_dynamic_buffer_append(
3108 &client->communication.outbound.buffer, &msg,
3109 sizeof(msg));
3110 return ret;
3111 }
3112
3113 static
3114 int send_evaluation_to_clients(const struct lttng_trigger *trigger,
3115 const struct lttng_evaluation *evaluation,
3116 struct notification_client_list* client_list,
3117 struct notification_thread_state *state,
3118 uid_t channel_uid, gid_t channel_gid)
3119 {
3120 int ret = 0;
3121 struct lttng_dynamic_buffer msg_buffer;
3122 struct notification_client_list_element *client_list_element, *tmp;
3123 const struct lttng_notification notification = {
3124 .condition = (struct lttng_condition *) lttng_trigger_get_const_condition(trigger),
3125 .evaluation = (struct lttng_evaluation *) evaluation,
3126 };
3127 struct lttng_notification_channel_message msg_header = {
3128 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION,
3129 };
3130
3131 lttng_dynamic_buffer_init(&msg_buffer);
3132
3133 ret = lttng_dynamic_buffer_append(&msg_buffer, &msg_header,
3134 sizeof(msg_header));
3135 if (ret) {
3136 goto end;
3137 }
3138
3139 ret = lttng_notification_serialize(&notification, &msg_buffer);
3140 if (ret) {
3141 ERR("[notification-thread] Failed to serialize notification");
3142 ret = -1;
3143 goto end;
3144 }
3145
3146 /* Update payload size. */
3147 ((struct lttng_notification_channel_message * ) msg_buffer.data)->size =
3148 (uint32_t) (msg_buffer.size - sizeof(msg_header));
3149
3150 cds_list_for_each_entry_safe(client_list_element, tmp,
3151 &client_list->list, node) {
3152 struct notification_client *client =
3153 client_list_element->client;
3154
3155 if (client->uid != channel_uid && client->gid != channel_gid &&
3156 client->uid != 0) {
3157 /* Client is not allowed to monitor this channel. */
3158 DBG("[notification-thread] Skipping client at it does not have the permission to receive notification for this channel");
3159 continue;
3160 }
3161
3162 DBG("[notification-thread] Sending notification to client (fd = %i, %zu bytes)",
3163 client->socket, msg_buffer.size);
3164 if (client->communication.outbound.buffer.size) {
3165 /*
3166 * Outgoing data is already buffered for this client;
3167 * drop the notification and enqueue a "dropped
3168 * notification" message if this is the first dropped
3169 * notification since the socket spilled-over to the
3170 * queue.
3171 */
3172 DBG("[notification-thread] Dropping notification addressed to client (socket fd = %i)",
3173 client->socket);
3174 if (!client->communication.outbound.dropped_notification) {
3175 client->communication.outbound.dropped_notification = true;
3176 ret = client_enqueue_dropped_notification(
3177 client, state);
3178 if (ret) {
3179 goto end;
3180 }
3181 }
3182 continue;
3183 }
3184
3185 ret = lttng_dynamic_buffer_append_buffer(
3186 &client->communication.outbound.buffer,
3187 &msg_buffer);
3188 if (ret) {
3189 goto end;
3190 }
3191
3192 ret = client_flush_outgoing_queue(client, state);
3193 if (ret) {
3194 goto end;
3195 }
3196 }
3197 ret = 0;
3198 end:
3199 lttng_dynamic_buffer_reset(&msg_buffer);
3200 return ret;
3201 }
3202
3203 int handle_notification_thread_channel_sample(
3204 struct notification_thread_state *state, int pipe,
3205 enum lttng_domain_type domain)
3206 {
3207 int ret = 0;
3208 struct lttcomm_consumer_channel_monitor_msg sample_msg;
3209 struct channel_info *channel_info;
3210 struct cds_lfht_node *node;
3211 struct cds_lfht_iter iter;
3212 struct lttng_channel_trigger_list *trigger_list;
3213 struct lttng_trigger_list_element *trigger_list_element;
3214 bool previous_sample_available = false;
3215 struct channel_state_sample previous_sample, latest_sample;
3216 uint64_t previous_session_consumed_total, latest_session_consumed_total;
3217
3218 /*
3219 * The monitoring pipe only holds messages smaller than PIPE_BUF,
3220 * ensuring that read/write of sampling messages are atomic.
3221 */
3222 ret = lttng_read(pipe, &sample_msg, sizeof(sample_msg));
3223 if (ret != sizeof(sample_msg)) {
3224 ERR("[notification-thread] Failed to read from monitoring pipe (fd = %i)",
3225 pipe);
3226 ret = -1;
3227 goto end;
3228 }
3229
3230 ret = 0;
3231 latest_sample.key.key = sample_msg.key;
3232 latest_sample.key.domain = domain;
3233 latest_sample.highest_usage = sample_msg.highest;
3234 latest_sample.lowest_usage = sample_msg.lowest;
3235 latest_sample.channel_total_consumed = sample_msg.total_consumed;
3236
3237 rcu_read_lock();
3238
3239 /* Retrieve the channel's informations */
3240 cds_lfht_lookup(state->channels_ht,
3241 hash_channel_key(&latest_sample.key),
3242 match_channel_info,
3243 &latest_sample.key,
3244 &iter);
3245 node = cds_lfht_iter_get_node(&iter);
3246 if (caa_unlikely(!node)) {
3247 /*
3248 * Not an error since the consumer can push a sample to the pipe
3249 * and the rest of the session daemon could notify us of the
3250 * channel's destruction before we get a chance to process that
3251 * sample.
3252 */
3253 DBG("[notification-thread] Received a sample for an unknown channel from consumerd, key = %" PRIu64 " in %s domain",
3254 latest_sample.key.key,
3255 domain == LTTNG_DOMAIN_KERNEL ? "kernel" :
3256 "user space");
3257 goto end_unlock;
3258 }
3259 channel_info = caa_container_of(node, struct channel_info,
3260 channels_ht_node);
3261 DBG("[notification-thread] Handling channel sample for channel %s (key = %" PRIu64 ") in session %s (highest usage = %" PRIu64 ", lowest usage = %" PRIu64", total consumed = %" PRIu64")",
3262 channel_info->name,
3263 latest_sample.key.key,
3264 channel_info->session_info->name,
3265 latest_sample.highest_usage,
3266 latest_sample.lowest_usage,
3267 latest_sample.channel_total_consumed);
3268
3269 previous_session_consumed_total =
3270 channel_info->session_info->consumed_data_size;
3271
3272 /* Retrieve the channel's last sample, if it exists, and update it. */
3273 cds_lfht_lookup(state->channel_state_ht,
3274 hash_channel_key(&latest_sample.key),
3275 match_channel_state_sample,
3276 &latest_sample.key,
3277 &iter);
3278 node = cds_lfht_iter_get_node(&iter);
3279 if (caa_likely(node)) {
3280 struct channel_state_sample *stored_sample;
3281
3282 /* Update the sample stored. */
3283 stored_sample = caa_container_of(node,
3284 struct channel_state_sample,
3285 channel_state_ht_node);
3286
3287 memcpy(&previous_sample, stored_sample,
3288 sizeof(previous_sample));
3289 stored_sample->highest_usage = latest_sample.highest_usage;
3290 stored_sample->lowest_usage = latest_sample.lowest_usage;
3291 stored_sample->channel_total_consumed = latest_sample.channel_total_consumed;
3292 previous_sample_available = true;
3293
3294 latest_session_consumed_total =
3295 previous_session_consumed_total +
3296 (latest_sample.channel_total_consumed - previous_sample.channel_total_consumed);
3297 } else {
3298 /*
3299 * This is the channel's first sample, allocate space for and
3300 * store the new sample.
3301 */
3302 struct channel_state_sample *stored_sample;
3303
3304 stored_sample = zmalloc(sizeof(*stored_sample));
3305 if (!stored_sample) {
3306 ret = -1;
3307 goto end_unlock;
3308 }
3309
3310 memcpy(stored_sample, &latest_sample, sizeof(*stored_sample));
3311 cds_lfht_node_init(&stored_sample->channel_state_ht_node);
3312 cds_lfht_add(state->channel_state_ht,
3313 hash_channel_key(&stored_sample->key),
3314 &stored_sample->channel_state_ht_node);
3315
3316 latest_session_consumed_total =
3317 previous_session_consumed_total +
3318 latest_sample.channel_total_consumed;
3319 }
3320
3321 channel_info->session_info->consumed_data_size =
3322 latest_session_consumed_total;
3323
3324 /* Find triggers associated with this channel. */
3325 cds_lfht_lookup(state->channel_triggers_ht,
3326 hash_channel_key(&latest_sample.key),
3327 match_channel_trigger_list,
3328 &latest_sample.key,
3329 &iter);
3330 node = cds_lfht_iter_get_node(&iter);
3331 if (caa_likely(!node)) {
3332 goto end_unlock;
3333 }
3334
3335 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
3336 channel_triggers_ht_node);
3337 cds_list_for_each_entry(trigger_list_element, &trigger_list->list,
3338 node) {
3339 const struct lttng_condition *condition;
3340 const struct lttng_action *action;
3341 const struct lttng_trigger *trigger;
3342 struct notification_client_list *client_list;
3343 struct lttng_evaluation *evaluation = NULL;
3344
3345 trigger = trigger_list_element->trigger;
3346 condition = lttng_trigger_get_const_condition(trigger);
3347 assert(condition);
3348 action = lttng_trigger_get_const_action(trigger);
3349
3350 /* Notify actions are the only type currently supported. */
3351 assert(lttng_action_get_type_const(action) ==
3352 LTTNG_ACTION_TYPE_NOTIFY);
3353
3354 /*
3355 * Check if any client is subscribed to the result of this
3356 * evaluation.
3357 */
3358 client_list = get_client_list_from_condition(state, condition);
3359 assert(client_list);
3360 if (cds_list_empty(&client_list->list)) {
3361 /*
3362 * No clients interested in the evaluation's result,
3363 * skip it.
3364 */
3365 continue;
3366 }
3367
3368 ret = evaluate_buffer_condition(condition, &evaluation, state,
3369 previous_sample_available ? &previous_sample : NULL,
3370 &latest_sample,
3371 previous_session_consumed_total,
3372 latest_session_consumed_total,
3373 channel_info);
3374 if (caa_unlikely(ret)) {
3375 goto end_unlock;
3376 }
3377
3378 if (caa_likely(!evaluation)) {
3379 continue;
3380 }
3381
3382 /* Dispatch evaluation result to all clients. */
3383 ret = send_evaluation_to_clients(trigger_list_element->trigger,
3384 evaluation, client_list, state,
3385 channel_info->session_info->uid,
3386 channel_info->session_info->gid);
3387 lttng_evaluation_destroy(evaluation);
3388 if (caa_unlikely(ret)) {
3389 goto end_unlock;
3390 }
3391 }
3392 end_unlock:
3393 rcu_read_unlock();
3394 end:
3395 return ret;
3396 }
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