bdbac0c4001f44f218ea0821eab5891972d35043
[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 break;
1865 }
1866 default:
1867 ret = 1;
1868 }
1869 end:
1870 return ret;
1871 }
1872
1873 /* Must be called with RCU read lock held. */
1874 static
1875 int bind_trigger_to_matching_session(const struct lttng_trigger *trigger,
1876 struct notification_thread_state *state)
1877 {
1878 int ret = 0;
1879 const struct lttng_condition *condition;
1880 const char *session_name;
1881 struct lttng_session_trigger_list *trigger_list;
1882
1883 condition = lttng_trigger_get_const_condition(trigger);
1884 switch (lttng_condition_get_type(condition)) {
1885 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
1886 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
1887 {
1888 enum lttng_condition_status status;
1889
1890 status = lttng_condition_session_rotation_get_session_name(
1891 condition, &session_name);
1892 if (status != LTTNG_CONDITION_STATUS_OK) {
1893 ERR("[notification-thread] Failed to bind trigger to session: unable to get 'session_rotation' condition's session name");
1894 ret = -1;
1895 goto end;
1896 }
1897 break;
1898 }
1899 default:
1900 ret = -1;
1901 goto end;
1902 }
1903
1904 trigger_list = get_session_trigger_list(state, session_name);
1905 if (!trigger_list) {
1906 DBG("[notification-thread] Unable to bind trigger applying to session \"%s\" as it is not yet known to the notification system",
1907 session_name);
1908 goto end;
1909
1910 }
1911
1912 DBG("[notification-thread] Newly registered trigger bound to session \"%s\"",
1913 session_name);
1914 ret = lttng_session_trigger_list_add(trigger_list, trigger);
1915 end:
1916 return ret;
1917 }
1918
1919 /* Must be called with RCU read lock held. */
1920 static
1921 int bind_trigger_to_matching_channels(const struct lttng_trigger *trigger,
1922 struct notification_thread_state *state)
1923 {
1924 int ret = 0;
1925 struct cds_lfht_node *node;
1926 struct cds_lfht_iter iter;
1927 struct channel_info *channel;
1928
1929 cds_lfht_for_each_entry(state->channels_ht, &iter, channel,
1930 channels_ht_node) {
1931 struct lttng_trigger_list_element *trigger_list_element;
1932 struct lttng_channel_trigger_list *trigger_list;
1933 struct cds_lfht_iter lookup_iter;
1934
1935 if (!trigger_applies_to_channel(trigger, channel)) {
1936 continue;
1937 }
1938
1939 cds_lfht_lookup(state->channel_triggers_ht,
1940 hash_channel_key(&channel->key),
1941 match_channel_trigger_list,
1942 &channel->key,
1943 &lookup_iter);
1944 node = cds_lfht_iter_get_node(&lookup_iter);
1945 assert(node);
1946 trigger_list = caa_container_of(node,
1947 struct lttng_channel_trigger_list,
1948 channel_triggers_ht_node);
1949
1950 trigger_list_element = zmalloc(sizeof(*trigger_list_element));
1951 if (!trigger_list_element) {
1952 ret = -1;
1953 goto end;
1954 }
1955 CDS_INIT_LIST_HEAD(&trigger_list_element->node);
1956 trigger_list_element->trigger = trigger;
1957 cds_list_add(&trigger_list_element->node, &trigger_list->list);
1958 DBG("[notification-thread] Newly registered trigger bound to channel \"%s\"",
1959 channel->name);
1960 }
1961 end:
1962 return ret;
1963 }
1964
1965 /*
1966 * FIXME A client's credentials are not checked when registering a trigger, nor
1967 * are they stored alongside with the trigger.
1968 *
1969 * The effects of this are benign since:
1970 * - The client will succeed in registering the trigger, as it is valid,
1971 * - The trigger will, internally, be bound to the channel/session,
1972 * - The notifications will not be sent since the client's credentials
1973 * are checked against the channel at that moment.
1974 *
1975 * If this function returns a non-zero value, it means something is
1976 * fundamentally broken and the whole subsystem/thread will be torn down.
1977 *
1978 * If a non-fatal error occurs, just set the cmd_result to the appropriate
1979 * error code.
1980 */
1981 static
1982 int handle_notification_thread_command_register_trigger(
1983 struct notification_thread_state *state,
1984 struct lttng_trigger *trigger,
1985 enum lttng_error_code *cmd_result)
1986 {
1987 int ret = 0;
1988 struct lttng_condition *condition;
1989 struct notification_client *client;
1990 struct notification_client_list *client_list = NULL;
1991 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1992 struct notification_client_list_element *client_list_element, *tmp;
1993 struct cds_lfht_node *node;
1994 struct cds_lfht_iter iter;
1995 bool free_trigger = true;
1996
1997 rcu_read_lock();
1998
1999 condition = lttng_trigger_get_condition(trigger);
2000 assert(condition);
2001
2002 ret = condition_is_supported(condition);
2003 if (ret < 0) {
2004 goto error;
2005 } else if (ret == 0) {
2006 *cmd_result = LTTNG_ERR_NOT_SUPPORTED;
2007 goto error;
2008 } else {
2009 /* Feature is supported, continue. */
2010 ret = 0;
2011 }
2012
2013 trigger_ht_element = zmalloc(sizeof(*trigger_ht_element));
2014 if (!trigger_ht_element) {
2015 ret = -1;
2016 goto error;
2017 }
2018
2019 /* Add trigger to the trigger_ht. */
2020 cds_lfht_node_init(&trigger_ht_element->node);
2021 trigger_ht_element->trigger = trigger;
2022
2023 node = cds_lfht_add_unique(state->triggers_ht,
2024 lttng_condition_hash(condition),
2025 match_condition,
2026 condition,
2027 &trigger_ht_element->node);
2028 if (node != &trigger_ht_element->node) {
2029 /* Not a fatal error, simply report it to the client. */
2030 *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
2031 goto error_free_ht_element;
2032 }
2033
2034 /*
2035 * Ownership of the trigger and of its wrapper was transfered to
2036 * the triggers_ht.
2037 */
2038 trigger_ht_element = NULL;
2039 free_trigger = false;
2040
2041 /*
2042 * The rest only applies to triggers that have a "notify" action.
2043 * It is not skipped as this is the only action type currently
2044 * supported.
2045 */
2046 client_list = zmalloc(sizeof(*client_list));
2047 if (!client_list) {
2048 ret = -1;
2049 goto error_free_ht_element;
2050 }
2051 cds_lfht_node_init(&client_list->notification_trigger_ht_node);
2052 CDS_INIT_LIST_HEAD(&client_list->list);
2053 client_list->trigger = trigger;
2054
2055 /* Build a list of clients to which this new trigger applies. */
2056 cds_lfht_for_each_entry(state->client_socket_ht, &iter, client,
2057 client_socket_ht_node) {
2058 if (!trigger_applies_to_client(trigger, client)) {
2059 continue;
2060 }
2061
2062 client_list_element = zmalloc(sizeof(*client_list_element));
2063 if (!client_list_element) {
2064 ret = -1;
2065 goto error_free_client_list;
2066 }
2067 CDS_INIT_LIST_HEAD(&client_list_element->node);
2068 client_list_element->client = client;
2069 cds_list_add(&client_list_element->node, &client_list->list);
2070 }
2071
2072 cds_lfht_add(state->notification_trigger_clients_ht,
2073 lttng_condition_hash(condition),
2074 &client_list->notification_trigger_ht_node);
2075
2076 switch (get_condition_binding_object(condition)) {
2077 case LTTNG_OBJECT_TYPE_SESSION:
2078 /* Add the trigger to the list if it matches a known session. */
2079 ret = bind_trigger_to_matching_session(trigger, state);
2080 if (ret) {
2081 goto error_free_client_list;
2082 }
2083 break;
2084 case LTTNG_OBJECT_TYPE_CHANNEL:
2085 /*
2086 * Add the trigger to list of triggers bound to the channels
2087 * currently known.
2088 */
2089 ret = bind_trigger_to_matching_channels(trigger, state);
2090 if (ret) {
2091 goto error_free_client_list;
2092 }
2093 break;
2094 case LTTNG_OBJECT_TYPE_NONE:
2095 break;
2096 default:
2097 ERR("[notification-thread] Unknown object type on which to bind a newly registered trigger was encountered");
2098 ret = -1;
2099 goto error_free_client_list;
2100 }
2101
2102 /*
2103 * Since there is nothing preventing clients from subscribing to a
2104 * condition before the corresponding trigger is registered, we have
2105 * to evaluate this new condition right away.
2106 *
2107 * At some point, we were waiting for the next "evaluation" (e.g. on
2108 * reception of a channel sample) to evaluate this new condition, but
2109 * that was broken.
2110 *
2111 * The reason it was broken is that waiting for the next sample
2112 * does not allow us to properly handle transitions for edge-triggered
2113 * conditions.
2114 *
2115 * Consider this example: when we handle a new channel sample, we
2116 * evaluate each conditions twice: once with the previous state, and
2117 * again with the newest state. We then use those two results to
2118 * determine whether a state change happened: a condition was false and
2119 * became true. If a state change happened, we have to notify clients.
2120 *
2121 * Now, if a client subscribes to a given notification and registers
2122 * a trigger *after* that subscription, we have to make sure the
2123 * condition is evaluated at this point while considering only the
2124 * current state. Otherwise, the next evaluation cycle may only see
2125 * that the evaluations remain the same (true for samples n-1 and n) and
2126 * the client will never know that the condition has been met.
2127 */
2128 cds_list_for_each_entry_safe(client_list_element, tmp,
2129 &client_list->list, node) {
2130 ret = evaluate_condition_for_client(trigger, condition,
2131 client_list_element->client, state);
2132 if (ret) {
2133 goto error_free_client_list;
2134 }
2135 }
2136
2137 /*
2138 * Client list ownership transferred to the
2139 * notification_trigger_clients_ht.
2140 */
2141 client_list = NULL;
2142
2143 *cmd_result = LTTNG_OK;
2144 error_free_client_list:
2145 if (client_list) {
2146 cds_list_for_each_entry_safe(client_list_element, tmp,
2147 &client_list->list, node) {
2148 free(client_list_element);
2149 }
2150 free(client_list);
2151 }
2152 error_free_ht_element:
2153 free(trigger_ht_element);
2154 error:
2155 if (free_trigger) {
2156 struct lttng_action *action = lttng_trigger_get_action(trigger);
2157
2158 lttng_condition_destroy(condition);
2159 lttng_action_destroy(action);
2160 lttng_trigger_destroy(trigger);
2161 }
2162 rcu_read_unlock();
2163 return ret;
2164 }
2165
2166 static
2167 void free_notification_client_list_rcu(struct rcu_head *node)
2168 {
2169 free(caa_container_of(node, struct notification_client_list,
2170 rcu_node));
2171 }
2172
2173 static
2174 void free_lttng_trigger_ht_element_rcu(struct rcu_head *node)
2175 {
2176 free(caa_container_of(node, struct lttng_trigger_ht_element,
2177 rcu_node));
2178 }
2179
2180 static
2181 int handle_notification_thread_command_unregister_trigger(
2182 struct notification_thread_state *state,
2183 struct lttng_trigger *trigger,
2184 enum lttng_error_code *_cmd_reply)
2185 {
2186 struct cds_lfht_iter iter;
2187 struct cds_lfht_node *triggers_ht_node;
2188 struct lttng_channel_trigger_list *trigger_list;
2189 struct notification_client_list *client_list;
2190 struct notification_client_list_element *client_list_element, *tmp;
2191 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
2192 struct lttng_condition *condition = lttng_trigger_get_condition(
2193 trigger);
2194 struct lttng_action *action;
2195 enum lttng_error_code cmd_reply;
2196
2197 rcu_read_lock();
2198
2199 cds_lfht_lookup(state->triggers_ht,
2200 lttng_condition_hash(condition),
2201 match_condition,
2202 condition,
2203 &iter);
2204 triggers_ht_node = cds_lfht_iter_get_node(&iter);
2205 if (!triggers_ht_node) {
2206 cmd_reply = LTTNG_ERR_TRIGGER_NOT_FOUND;
2207 goto end;
2208 } else {
2209 cmd_reply = LTTNG_OK;
2210 }
2211
2212 /* Remove trigger from channel_triggers_ht. */
2213 cds_lfht_for_each_entry(state->channel_triggers_ht, &iter, trigger_list,
2214 channel_triggers_ht_node) {
2215 struct lttng_trigger_list_element *trigger_element, *tmp;
2216
2217 cds_list_for_each_entry_safe(trigger_element, tmp,
2218 &trigger_list->list, node) {
2219 const struct lttng_condition *current_condition =
2220 lttng_trigger_get_const_condition(
2221 trigger_element->trigger);
2222
2223 assert(current_condition);
2224 if (!lttng_condition_is_equal(condition,
2225 current_condition)) {
2226 continue;
2227 }
2228
2229 DBG("[notification-thread] Removed trigger from channel_triggers_ht");
2230 cds_list_del(&trigger_element->node);
2231 /* A trigger can only appear once per channel */
2232 break;
2233 }
2234 }
2235
2236 /*
2237 * Remove and release the client list from
2238 * notification_trigger_clients_ht.
2239 */
2240 client_list = get_client_list_from_condition(state, condition);
2241 assert(client_list);
2242
2243 cds_list_for_each_entry_safe(client_list_element, tmp,
2244 &client_list->list, node) {
2245 free(client_list_element);
2246 }
2247 cds_lfht_del(state->notification_trigger_clients_ht,
2248 &client_list->notification_trigger_ht_node);
2249 call_rcu(&client_list->rcu_node, free_notification_client_list_rcu);
2250
2251 /* Remove trigger from triggers_ht. */
2252 trigger_ht_element = caa_container_of(triggers_ht_node,
2253 struct lttng_trigger_ht_element, node);
2254 cds_lfht_del(state->triggers_ht, triggers_ht_node);
2255
2256 condition = lttng_trigger_get_condition(trigger_ht_element->trigger);
2257 lttng_condition_destroy(condition);
2258 action = lttng_trigger_get_action(trigger_ht_element->trigger);
2259 lttng_action_destroy(action);
2260 lttng_trigger_destroy(trigger_ht_element->trigger);
2261 call_rcu(&trigger_ht_element->rcu_node, free_lttng_trigger_ht_element_rcu);
2262 end:
2263 rcu_read_unlock();
2264 if (_cmd_reply) {
2265 *_cmd_reply = cmd_reply;
2266 }
2267 return 0;
2268 }
2269
2270 /* Returns 0 on success, 1 on exit requested, negative value on error. */
2271 int handle_notification_thread_command(
2272 struct notification_thread_handle *handle,
2273 struct notification_thread_state *state)
2274 {
2275 int ret;
2276 uint64_t counter;
2277 struct notification_thread_command *cmd;
2278
2279 /* Read the event pipe to put it back into a quiescent state. */
2280 ret = lttng_read(lttng_pipe_get_readfd(handle->cmd_queue.event_pipe), &counter,
2281 sizeof(counter));
2282 if (ret != sizeof(counter)) {
2283 goto error;
2284 }
2285
2286 pthread_mutex_lock(&handle->cmd_queue.lock);
2287 cmd = cds_list_first_entry(&handle->cmd_queue.list,
2288 struct notification_thread_command, cmd_list_node);
2289 switch (cmd->type) {
2290 case NOTIFICATION_COMMAND_TYPE_REGISTER_TRIGGER:
2291 DBG("[notification-thread] Received register trigger command");
2292 ret = handle_notification_thread_command_register_trigger(
2293 state, cmd->parameters.trigger,
2294 &cmd->reply_code);
2295 break;
2296 case NOTIFICATION_COMMAND_TYPE_UNREGISTER_TRIGGER:
2297 DBG("[notification-thread] Received unregister trigger command");
2298 ret = handle_notification_thread_command_unregister_trigger(
2299 state, cmd->parameters.trigger,
2300 &cmd->reply_code);
2301 break;
2302 case NOTIFICATION_COMMAND_TYPE_ADD_CHANNEL:
2303 DBG("[notification-thread] Received add channel command");
2304 ret = handle_notification_thread_command_add_channel(
2305 state,
2306 cmd->parameters.add_channel.session.name,
2307 cmd->parameters.add_channel.session.uid,
2308 cmd->parameters.add_channel.session.gid,
2309 cmd->parameters.add_channel.channel.name,
2310 cmd->parameters.add_channel.channel.domain,
2311 cmd->parameters.add_channel.channel.key,
2312 cmd->parameters.add_channel.channel.capacity,
2313 &cmd->reply_code);
2314 break;
2315 case NOTIFICATION_COMMAND_TYPE_REMOVE_CHANNEL:
2316 DBG("[notification-thread] Received remove channel command");
2317 ret = handle_notification_thread_command_remove_channel(
2318 state, cmd->parameters.remove_channel.key,
2319 cmd->parameters.remove_channel.domain,
2320 &cmd->reply_code);
2321 break;
2322 case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING:
2323 case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED:
2324 DBG("[notification-thread] Received session rotation %s command",
2325 cmd->type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING ?
2326 "ongoing" : "completed");
2327 ret = handle_notification_thread_command_session_rotation(
2328 state,
2329 cmd->type,
2330 cmd->parameters.session_rotation.session_name,
2331 cmd->parameters.session_rotation.uid,
2332 cmd->parameters.session_rotation.gid,
2333 cmd->parameters.session_rotation.trace_archive_chunk_id,
2334 cmd->parameters.session_rotation.location,
2335 &cmd->reply_code);
2336 break;
2337 case NOTIFICATION_COMMAND_TYPE_QUIT:
2338 DBG("[notification-thread] Received quit command");
2339 cmd->reply_code = LTTNG_OK;
2340 ret = 1;
2341 goto end;
2342 default:
2343 ERR("[notification-thread] Unknown internal command received");
2344 goto error_unlock;
2345 }
2346
2347 if (ret) {
2348 goto error_unlock;
2349 }
2350 end:
2351 cds_list_del(&cmd->cmd_list_node);
2352 lttng_waiter_wake_up(&cmd->reply_waiter);
2353 pthread_mutex_unlock(&handle->cmd_queue.lock);
2354 return ret;
2355 error_unlock:
2356 /* Wake-up and return a fatal error to the calling thread. */
2357 lttng_waiter_wake_up(&cmd->reply_waiter);
2358 pthread_mutex_unlock(&handle->cmd_queue.lock);
2359 cmd->reply_code = LTTNG_ERR_FATAL;
2360 error:
2361 /* Indicate a fatal error to the caller. */
2362 return -1;
2363 }
2364
2365 static
2366 unsigned long hash_client_socket(int socket)
2367 {
2368 return hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed);
2369 }
2370
2371 static
2372 int socket_set_non_blocking(int socket)
2373 {
2374 int ret, flags;
2375
2376 /* Set the pipe as non-blocking. */
2377 ret = fcntl(socket, F_GETFL, 0);
2378 if (ret == -1) {
2379 PERROR("fcntl get socket flags");
2380 goto end;
2381 }
2382 flags = ret;
2383
2384 ret = fcntl(socket, F_SETFL, flags | O_NONBLOCK);
2385 if (ret == -1) {
2386 PERROR("fcntl set O_NONBLOCK socket flag");
2387 goto end;
2388 }
2389 DBG("Client socket (fd = %i) set as non-blocking", socket);
2390 end:
2391 return ret;
2392 }
2393
2394 static
2395 int client_reset_inbound_state(struct notification_client *client)
2396 {
2397 int ret;
2398
2399 ret = lttng_dynamic_buffer_set_size(
2400 &client->communication.inbound.buffer, 0);
2401 assert(!ret);
2402
2403 client->communication.inbound.bytes_to_receive =
2404 sizeof(struct lttng_notification_channel_message);
2405 client->communication.inbound.msg_type =
2406 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN;
2407 LTTNG_SOCK_SET_UID_CRED(&client->communication.inbound.creds, -1);
2408 LTTNG_SOCK_SET_GID_CRED(&client->communication.inbound.creds, -1);
2409 ret = lttng_dynamic_buffer_set_size(
2410 &client->communication.inbound.buffer,
2411 client->communication.inbound.bytes_to_receive);
2412 return ret;
2413 }
2414
2415 int handle_notification_thread_client_connect(
2416 struct notification_thread_state *state)
2417 {
2418 int ret;
2419 struct notification_client *client;
2420
2421 DBG("[notification-thread] Handling new notification channel client connection");
2422
2423 client = zmalloc(sizeof(*client));
2424 if (!client) {
2425 /* Fatal error. */
2426 ret = -1;
2427 goto error;
2428 }
2429 CDS_INIT_LIST_HEAD(&client->condition_list);
2430 lttng_dynamic_buffer_init(&client->communication.inbound.buffer);
2431 lttng_dynamic_buffer_init(&client->communication.outbound.buffer);
2432 client->communication.inbound.expect_creds = true;
2433 ret = client_reset_inbound_state(client);
2434 if (ret) {
2435 ERR("[notification-thread] Failed to reset client communication's inbound state");
2436 ret = 0;
2437 goto error;
2438 }
2439
2440 ret = lttcomm_accept_unix_sock(state->notification_channel_socket);
2441 if (ret < 0) {
2442 ERR("[notification-thread] Failed to accept new notification channel client connection");
2443 ret = 0;
2444 goto error;
2445 }
2446
2447 client->socket = ret;
2448
2449 ret = socket_set_non_blocking(client->socket);
2450 if (ret) {
2451 ERR("[notification-thread] Failed to set new notification channel client connection socket as non-blocking");
2452 goto error;
2453 }
2454
2455 ret = lttcomm_setsockopt_creds_unix_sock(client->socket);
2456 if (ret < 0) {
2457 ERR("[notification-thread] Failed to set socket options on new notification channel client socket");
2458 ret = 0;
2459 goto error;
2460 }
2461
2462 ret = lttng_poll_add(&state->events, client->socket,
2463 LPOLLIN | LPOLLERR |
2464 LPOLLHUP | LPOLLRDHUP);
2465 if (ret < 0) {
2466 ERR("[notification-thread] Failed to add notification channel client socket to poll set");
2467 ret = 0;
2468 goto error;
2469 }
2470 DBG("[notification-thread] Added new notification channel client socket (%i) to poll set",
2471 client->socket);
2472
2473 rcu_read_lock();
2474 cds_lfht_add(state->client_socket_ht,
2475 hash_client_socket(client->socket),
2476 &client->client_socket_ht_node);
2477 rcu_read_unlock();
2478
2479 return ret;
2480 error:
2481 notification_client_destroy(client, state);
2482 return ret;
2483 }
2484
2485 int handle_notification_thread_client_disconnect(
2486 int client_socket,
2487 struct notification_thread_state *state)
2488 {
2489 int ret = 0;
2490 struct notification_client *client;
2491
2492 rcu_read_lock();
2493 DBG("[notification-thread] Closing client connection (socket fd = %i)",
2494 client_socket);
2495 client = get_client_from_socket(client_socket, state);
2496 if (!client) {
2497 /* Internal state corruption, fatal error. */
2498 ERR("[notification-thread] Unable to find client (socket fd = %i)",
2499 client_socket);
2500 ret = -1;
2501 goto end;
2502 }
2503
2504 ret = lttng_poll_del(&state->events, client_socket);
2505 if (ret) {
2506 ERR("[notification-thread] Failed to remove client socket from poll set");
2507 }
2508 cds_lfht_del(state->client_socket_ht,
2509 &client->client_socket_ht_node);
2510 notification_client_destroy(client, state);
2511 end:
2512 rcu_read_unlock();
2513 return ret;
2514 }
2515
2516 int handle_notification_thread_client_disconnect_all(
2517 struct notification_thread_state *state)
2518 {
2519 struct cds_lfht_iter iter;
2520 struct notification_client *client;
2521 bool error_encoutered = false;
2522
2523 rcu_read_lock();
2524 DBG("[notification-thread] Closing all client connections");
2525 cds_lfht_for_each_entry(state->client_socket_ht, &iter, client,
2526 client_socket_ht_node) {
2527 int ret;
2528
2529 ret = handle_notification_thread_client_disconnect(
2530 client->socket, state);
2531 if (ret) {
2532 error_encoutered = true;
2533 }
2534 }
2535 rcu_read_unlock();
2536 return error_encoutered ? 1 : 0;
2537 }
2538
2539 int handle_notification_thread_trigger_unregister_all(
2540 struct notification_thread_state *state)
2541 {
2542 bool error_occurred = false;
2543 struct cds_lfht_iter iter;
2544 struct lttng_trigger_ht_element *trigger_ht_element;
2545
2546 rcu_read_lock();
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 rcu_read_unlock();
2556 return error_occurred ? -1 : 0;
2557 }
2558
2559 static
2560 int client_flush_outgoing_queue(struct notification_client *client,
2561 struct notification_thread_state *state)
2562 {
2563 ssize_t ret;
2564 size_t to_send_count;
2565
2566 assert(client->communication.outbound.buffer.size != 0);
2567 to_send_count = client->communication.outbound.buffer.size;
2568 DBG("[notification-thread] Flushing client (socket fd = %i) outgoing queue",
2569 client->socket);
2570
2571 ret = lttcomm_send_unix_sock_non_block(client->socket,
2572 client->communication.outbound.buffer.data,
2573 to_send_count);
2574 if ((ret < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) ||
2575 (ret > 0 && ret < to_send_count)) {
2576 DBG("[notification-thread] Client (socket fd = %i) outgoing queue could not be completely flushed",
2577 client->socket);
2578 to_send_count -= max(ret, 0);
2579
2580 memcpy(client->communication.outbound.buffer.data,
2581 client->communication.outbound.buffer.data +
2582 client->communication.outbound.buffer.size - to_send_count,
2583 to_send_count);
2584 ret = lttng_dynamic_buffer_set_size(
2585 &client->communication.outbound.buffer,
2586 to_send_count);
2587 if (ret) {
2588 goto error;
2589 }
2590
2591 /*
2592 * We want to be notified whenever there is buffer space
2593 * available to send the rest of the payload.
2594 */
2595 ret = lttng_poll_mod(&state->events, client->socket,
2596 CLIENT_POLL_MASK_IN_OUT);
2597 if (ret) {
2598 goto error;
2599 }
2600 } else if (ret < 0) {
2601 /* Generic error, disconnect the client. */
2602 ERR("[notification-thread] Failed to send flush outgoing queue, disconnecting client (socket fd = %i)",
2603 client->socket);
2604 ret = handle_notification_thread_client_disconnect(
2605 client->socket, state);
2606 if (ret) {
2607 goto error;
2608 }
2609 } else {
2610 /* No error and flushed the queue completely. */
2611 ret = lttng_dynamic_buffer_set_size(
2612 &client->communication.outbound.buffer, 0);
2613 if (ret) {
2614 goto error;
2615 }
2616 ret = lttng_poll_mod(&state->events, client->socket,
2617 CLIENT_POLL_MASK_IN);
2618 if (ret) {
2619 goto error;
2620 }
2621
2622 client->communication.outbound.queued_command_reply = false;
2623 client->communication.outbound.dropped_notification = false;
2624 }
2625
2626 return 0;
2627 error:
2628 return -1;
2629 }
2630
2631 static
2632 int client_send_command_reply(struct notification_client *client,
2633 struct notification_thread_state *state,
2634 enum lttng_notification_channel_status status)
2635 {
2636 int ret;
2637 struct lttng_notification_channel_command_reply reply = {
2638 .status = (int8_t) status,
2639 };
2640 struct lttng_notification_channel_message msg = {
2641 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY,
2642 .size = sizeof(reply),
2643 };
2644 char buffer[sizeof(msg) + sizeof(reply)];
2645
2646 if (client->communication.outbound.queued_command_reply) {
2647 /* Protocol error. */
2648 goto error;
2649 }
2650
2651 memcpy(buffer, &msg, sizeof(msg));
2652 memcpy(buffer + sizeof(msg), &reply, sizeof(reply));
2653 DBG("[notification-thread] Send command reply (%i)", (int) status);
2654
2655 /* Enqueue buffer to outgoing queue and flush it. */
2656 ret = lttng_dynamic_buffer_append(
2657 &client->communication.outbound.buffer,
2658 buffer, sizeof(buffer));
2659 if (ret) {
2660 goto error;
2661 }
2662
2663 ret = client_flush_outgoing_queue(client, state);
2664 if (ret) {
2665 goto error;
2666 }
2667
2668 if (client->communication.outbound.buffer.size != 0) {
2669 /* Queue could not be emptied. */
2670 client->communication.outbound.queued_command_reply = true;
2671 }
2672
2673 return 0;
2674 error:
2675 return -1;
2676 }
2677
2678 static
2679 int client_dispatch_message(struct notification_client *client,
2680 struct notification_thread_state *state)
2681 {
2682 int ret = 0;
2683
2684 if (client->communication.inbound.msg_type !=
2685 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE &&
2686 client->communication.inbound.msg_type !=
2687 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN &&
2688 !client->validated) {
2689 WARN("[notification-thread] client attempted a command before handshake");
2690 ret = -1;
2691 goto end;
2692 }
2693
2694 switch (client->communication.inbound.msg_type) {
2695 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN:
2696 {
2697 /*
2698 * Receiving message header. The function will be called again
2699 * once the rest of the message as been received and can be
2700 * interpreted.
2701 */
2702 const struct lttng_notification_channel_message *msg;
2703
2704 assert(sizeof(*msg) ==
2705 client->communication.inbound.buffer.size);
2706 msg = (const struct lttng_notification_channel_message *)
2707 client->communication.inbound.buffer.data;
2708
2709 if (msg->size == 0 || msg->size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) {
2710 ERR("[notification-thread] Invalid notification channel message: length = %u", msg->size);
2711 ret = -1;
2712 goto end;
2713 }
2714
2715 switch (msg->type) {
2716 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE:
2717 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE:
2718 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE:
2719 break;
2720 default:
2721 ret = -1;
2722 ERR("[notification-thread] Invalid notification channel message: unexpected message type");
2723 goto end;
2724 }
2725
2726 client->communication.inbound.bytes_to_receive = msg->size;
2727 client->communication.inbound.msg_type =
2728 (enum lttng_notification_channel_message_type) msg->type;
2729 ret = lttng_dynamic_buffer_set_size(
2730 &client->communication.inbound.buffer, msg->size);
2731 if (ret) {
2732 goto end;
2733 }
2734 break;
2735 }
2736 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE:
2737 {
2738 struct lttng_notification_channel_command_handshake *handshake_client;
2739 struct lttng_notification_channel_command_handshake handshake_reply = {
2740 .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR,
2741 .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR,
2742 };
2743 struct lttng_notification_channel_message msg_header = {
2744 .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE,
2745 .size = sizeof(handshake_reply),
2746 };
2747 enum lttng_notification_channel_status status =
2748 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
2749 char send_buffer[sizeof(msg_header) + sizeof(handshake_reply)];
2750
2751 memcpy(send_buffer, &msg_header, sizeof(msg_header));
2752 memcpy(send_buffer + sizeof(msg_header), &handshake_reply,
2753 sizeof(handshake_reply));
2754
2755 handshake_client =
2756 (struct lttng_notification_channel_command_handshake *)
2757 client->communication.inbound.buffer.data;
2758 client->major = handshake_client->major;
2759 client->minor = handshake_client->minor;
2760 if (!client->communication.inbound.creds_received) {
2761 ERR("[notification-thread] No credentials received from client");
2762 ret = -1;
2763 goto end;
2764 }
2765
2766 client->uid = LTTNG_SOCK_GET_UID_CRED(
2767 &client->communication.inbound.creds);
2768 client->gid = LTTNG_SOCK_GET_GID_CRED(
2769 &client->communication.inbound.creds);
2770 DBG("[notification-thread] Received handshake from client (uid = %u, gid = %u) with version %i.%i",
2771 client->uid, client->gid, (int) client->major,
2772 (int) client->minor);
2773
2774 if (handshake_client->major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) {
2775 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNSUPPORTED_VERSION;
2776 }
2777
2778 ret = lttng_dynamic_buffer_append(&client->communication.outbound.buffer,
2779 send_buffer, sizeof(send_buffer));
2780 if (ret) {
2781 ERR("[notification-thread] Failed to send protocol version to notification channel client");
2782 goto end;
2783 }
2784
2785 ret = client_flush_outgoing_queue(client, state);
2786 if (ret) {
2787 goto end;
2788 }
2789
2790 ret = client_send_command_reply(client, state, status);
2791 if (ret) {
2792 ERR("[notification-thread] Failed to send reply to notification channel client");
2793 goto end;
2794 }
2795
2796 /* Set reception state to receive the next message header. */
2797 ret = client_reset_inbound_state(client);
2798 if (ret) {
2799 ERR("[notification-thread] Failed to reset client communication's inbound state");
2800 goto end;
2801 }
2802 client->validated = true;
2803 break;
2804 }
2805 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE:
2806 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE:
2807 {
2808 struct lttng_condition *condition;
2809 enum lttng_notification_channel_status status =
2810 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
2811 const struct lttng_buffer_view condition_view =
2812 lttng_buffer_view_from_dynamic_buffer(
2813 &client->communication.inbound.buffer,
2814 0, -1);
2815 size_t expected_condition_size =
2816 client->communication.inbound.buffer.size;
2817
2818 ret = lttng_condition_create_from_buffer(&condition_view,
2819 &condition);
2820 if (ret != expected_condition_size) {
2821 ERR("[notification-thread] Malformed condition received from client");
2822 goto end;
2823 }
2824
2825 if (client->communication.inbound.msg_type ==
2826 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE) {
2827 ret = notification_thread_client_subscribe(client,
2828 condition, state, &status);
2829 } else {
2830 ret = notification_thread_client_unsubscribe(client,
2831 condition, state, &status);
2832 }
2833 if (ret) {
2834 goto end;
2835 }
2836
2837 ret = client_send_command_reply(client, state, status);
2838 if (ret) {
2839 ERR("[notification-thread] Failed to send reply to notification channel client");
2840 goto end;
2841 }
2842
2843 /* Set reception state to receive the next message header. */
2844 ret = client_reset_inbound_state(client);
2845 if (ret) {
2846 ERR("[notification-thread] Failed to reset client communication's inbound state");
2847 goto end;
2848 }
2849 break;
2850 }
2851 default:
2852 abort();
2853 }
2854 end:
2855 return ret;
2856 }
2857
2858 /* Incoming data from client. */
2859 int handle_notification_thread_client_in(
2860 struct notification_thread_state *state, int socket)
2861 {
2862 int ret = 0;
2863 struct notification_client *client;
2864 ssize_t recv_ret;
2865 size_t offset;
2866
2867 client = get_client_from_socket(socket, state);
2868 if (!client) {
2869 /* Internal error, abort. */
2870 ret = -1;
2871 goto end;
2872 }
2873
2874 offset = client->communication.inbound.buffer.size -
2875 client->communication.inbound.bytes_to_receive;
2876 if (client->communication.inbound.expect_creds) {
2877 recv_ret = lttcomm_recv_creds_unix_sock(socket,
2878 client->communication.inbound.buffer.data + offset,
2879 client->communication.inbound.bytes_to_receive,
2880 &client->communication.inbound.creds);
2881 if (recv_ret > 0) {
2882 client->communication.inbound.expect_creds = false;
2883 client->communication.inbound.creds_received = true;
2884 }
2885 } else {
2886 recv_ret = lttcomm_recv_unix_sock_non_block(socket,
2887 client->communication.inbound.buffer.data + offset,
2888 client->communication.inbound.bytes_to_receive);
2889 }
2890 if (recv_ret < 0) {
2891 goto error_disconnect_client;
2892 }
2893
2894 client->communication.inbound.bytes_to_receive -= recv_ret;
2895 if (client->communication.inbound.bytes_to_receive == 0) {
2896 ret = client_dispatch_message(client, state);
2897 if (ret) {
2898 /*
2899 * Only returns an error if this client must be
2900 * disconnected.
2901 */
2902 goto error_disconnect_client;
2903 }
2904 } else {
2905 goto end;
2906 }
2907 end:
2908 return ret;
2909 error_disconnect_client:
2910 ret = handle_notification_thread_client_disconnect(socket, state);
2911 return ret;
2912 }
2913
2914 /* Client ready to receive outgoing data. */
2915 int handle_notification_thread_client_out(
2916 struct notification_thread_state *state, int socket)
2917 {
2918 int ret;
2919 struct notification_client *client;
2920
2921 client = get_client_from_socket(socket, state);
2922 if (!client) {
2923 /* Internal error, abort. */
2924 ret = -1;
2925 goto end;
2926 }
2927
2928 ret = client_flush_outgoing_queue(client, state);
2929 if (ret) {
2930 goto end;
2931 }
2932 end:
2933 return ret;
2934 }
2935
2936 static
2937 bool evaluate_buffer_usage_condition(const struct lttng_condition *condition,
2938 const struct channel_state_sample *sample,
2939 uint64_t buffer_capacity)
2940 {
2941 bool result = false;
2942 uint64_t threshold;
2943 enum lttng_condition_type condition_type;
2944 const struct lttng_condition_buffer_usage *use_condition = container_of(
2945 condition, struct lttng_condition_buffer_usage,
2946 parent);
2947
2948 if (use_condition->threshold_bytes.set) {
2949 threshold = use_condition->threshold_bytes.value;
2950 } else {
2951 /*
2952 * Threshold was expressed as a ratio.
2953 *
2954 * TODO the threshold (in bytes) of conditions expressed
2955 * as a ratio of total buffer size could be cached to
2956 * forego this double-multiplication or it could be performed
2957 * as fixed-point math.
2958 *
2959 * Note that caching should accomodate the case where the
2960 * condition applies to multiple channels (i.e. don't assume
2961 * that all channels matching my_chann* have the same size...)
2962 */
2963 threshold = (uint64_t) (use_condition->threshold_ratio.value *
2964 (double) buffer_capacity);
2965 }
2966
2967 condition_type = lttng_condition_get_type(condition);
2968 if (condition_type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW) {
2969 DBG("[notification-thread] Low buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
2970 threshold, sample->highest_usage);
2971
2972 /*
2973 * The low condition should only be triggered once _all_ of the
2974 * streams in a channel have gone below the "low" threshold.
2975 */
2976 if (sample->highest_usage <= threshold) {
2977 result = true;
2978 }
2979 } else {
2980 DBG("[notification-thread] High buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
2981 threshold, sample->highest_usage);
2982
2983 /*
2984 * For high buffer usage scenarios, we want to trigger whenever
2985 * _any_ of the streams has reached the "high" threshold.
2986 */
2987 if (sample->highest_usage >= threshold) {
2988 result = true;
2989 }
2990 }
2991
2992 return result;
2993 }
2994
2995 static
2996 bool evaluate_session_consumed_size_condition(
2997 const struct lttng_condition *condition,
2998 uint64_t session_consumed_size)
2999 {
3000 uint64_t threshold;
3001 const struct lttng_condition_session_consumed_size *size_condition =
3002 container_of(condition,
3003 struct lttng_condition_session_consumed_size,
3004 parent);
3005
3006 threshold = size_condition->consumed_threshold_bytes.value;
3007 DBG("[notification-thread] Session consumed size condition being evaluated: threshold = %" PRIu64 ", current size = %" PRIu64,
3008 threshold, session_consumed_size);
3009 return session_consumed_size >= threshold;
3010 }
3011
3012 static
3013 int evaluate_buffer_condition(const struct lttng_condition *condition,
3014 struct lttng_evaluation **evaluation,
3015 const struct notification_thread_state *state,
3016 const struct channel_state_sample *previous_sample,
3017 const struct channel_state_sample *latest_sample,
3018 uint64_t previous_session_consumed_total,
3019 uint64_t latest_session_consumed_total,
3020 struct channel_info *channel_info)
3021 {
3022 int ret = 0;
3023 enum lttng_condition_type condition_type;
3024 const bool previous_sample_available = !!previous_sample;
3025 bool previous_sample_result = false;
3026 bool latest_sample_result;
3027
3028 condition_type = lttng_condition_get_type(condition);
3029
3030 switch (condition_type) {
3031 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
3032 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
3033 if (caa_likely(previous_sample_available)) {
3034 previous_sample_result =
3035 evaluate_buffer_usage_condition(condition,
3036 previous_sample, channel_info->capacity);
3037 }
3038 latest_sample_result = evaluate_buffer_usage_condition(
3039 condition, latest_sample,
3040 channel_info->capacity);
3041 break;
3042 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
3043 if (caa_likely(previous_sample_available)) {
3044 previous_sample_result =
3045 evaluate_session_consumed_size_condition(
3046 condition,
3047 previous_session_consumed_total);
3048 }
3049 latest_sample_result =
3050 evaluate_session_consumed_size_condition(
3051 condition,
3052 latest_session_consumed_total);
3053 break;
3054 default:
3055 /* Unknown condition type; internal error. */
3056 abort();
3057 }
3058
3059 if (!latest_sample_result ||
3060 (previous_sample_result == latest_sample_result)) {
3061 /*
3062 * Only trigger on a condition evaluation transition.
3063 *
3064 * NOTE: This edge-triggered logic may not be appropriate for
3065 * future condition types.
3066 */
3067 goto end;
3068 }
3069
3070 if (!evaluation || !latest_sample_result) {
3071 goto end;
3072 }
3073
3074 switch (condition_type) {
3075 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
3076 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
3077 *evaluation = lttng_evaluation_buffer_usage_create(
3078 condition_type,
3079 latest_sample->highest_usage,
3080 channel_info->capacity);
3081 break;
3082 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
3083 *evaluation = lttng_evaluation_session_consumed_size_create(
3084 latest_session_consumed_total);
3085 break;
3086 default:
3087 abort();
3088 }
3089
3090 if (!*evaluation) {
3091 ret = -1;
3092 goto end;
3093 }
3094 end:
3095 return ret;
3096 }
3097
3098 static
3099 int client_enqueue_dropped_notification(struct notification_client *client,
3100 struct notification_thread_state *state)
3101 {
3102 int ret;
3103 struct lttng_notification_channel_message msg = {
3104 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED,
3105 .size = 0,
3106 };
3107
3108 ret = lttng_dynamic_buffer_append(
3109 &client->communication.outbound.buffer, &msg,
3110 sizeof(msg));
3111 return ret;
3112 }
3113
3114 static
3115 int send_evaluation_to_clients(const struct lttng_trigger *trigger,
3116 const struct lttng_evaluation *evaluation,
3117 struct notification_client_list* client_list,
3118 struct notification_thread_state *state,
3119 uid_t channel_uid, gid_t channel_gid)
3120 {
3121 int ret = 0;
3122 struct lttng_dynamic_buffer msg_buffer;
3123 struct notification_client_list_element *client_list_element, *tmp;
3124 const struct lttng_notification notification = {
3125 .condition = (struct lttng_condition *) lttng_trigger_get_const_condition(trigger),
3126 .evaluation = (struct lttng_evaluation *) evaluation,
3127 };
3128 struct lttng_notification_channel_message msg_header = {
3129 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION,
3130 };
3131
3132 lttng_dynamic_buffer_init(&msg_buffer);
3133
3134 ret = lttng_dynamic_buffer_append(&msg_buffer, &msg_header,
3135 sizeof(msg_header));
3136 if (ret) {
3137 goto end;
3138 }
3139
3140 ret = lttng_notification_serialize(&notification, &msg_buffer);
3141 if (ret) {
3142 ERR("[notification-thread] Failed to serialize notification");
3143 ret = -1;
3144 goto end;
3145 }
3146
3147 /* Update payload size. */
3148 ((struct lttng_notification_channel_message * ) msg_buffer.data)->size =
3149 (uint32_t) (msg_buffer.size - sizeof(msg_header));
3150
3151 cds_list_for_each_entry_safe(client_list_element, tmp,
3152 &client_list->list, node) {
3153 struct notification_client *client =
3154 client_list_element->client;
3155
3156 if (client->uid != channel_uid && client->gid != channel_gid &&
3157 client->uid != 0) {
3158 /* Client is not allowed to monitor this channel. */
3159 DBG("[notification-thread] Skipping client at it does not have the permission to receive notification for this channel");
3160 continue;
3161 }
3162
3163 DBG("[notification-thread] Sending notification to client (fd = %i, %zu bytes)",
3164 client->socket, msg_buffer.size);
3165 if (client->communication.outbound.buffer.size) {
3166 /*
3167 * Outgoing data is already buffered for this client;
3168 * drop the notification and enqueue a "dropped
3169 * notification" message if this is the first dropped
3170 * notification since the socket spilled-over to the
3171 * queue.
3172 */
3173 DBG("[notification-thread] Dropping notification addressed to client (socket fd = %i)",
3174 client->socket);
3175 if (!client->communication.outbound.dropped_notification) {
3176 client->communication.outbound.dropped_notification = true;
3177 ret = client_enqueue_dropped_notification(
3178 client, state);
3179 if (ret) {
3180 goto end;
3181 }
3182 }
3183 continue;
3184 }
3185
3186 ret = lttng_dynamic_buffer_append_buffer(
3187 &client->communication.outbound.buffer,
3188 &msg_buffer);
3189 if (ret) {
3190 goto end;
3191 }
3192
3193 ret = client_flush_outgoing_queue(client, state);
3194 if (ret) {
3195 goto end;
3196 }
3197 }
3198 ret = 0;
3199 end:
3200 lttng_dynamic_buffer_reset(&msg_buffer);
3201 return ret;
3202 }
3203
3204 int handle_notification_thread_channel_sample(
3205 struct notification_thread_state *state, int pipe,
3206 enum lttng_domain_type domain)
3207 {
3208 int ret = 0;
3209 struct lttcomm_consumer_channel_monitor_msg sample_msg;
3210 struct channel_info *channel_info;
3211 struct cds_lfht_node *node;
3212 struct cds_lfht_iter iter;
3213 struct lttng_channel_trigger_list *trigger_list;
3214 struct lttng_trigger_list_element *trigger_list_element;
3215 bool previous_sample_available = false;
3216 struct channel_state_sample previous_sample, latest_sample;
3217 uint64_t previous_session_consumed_total, latest_session_consumed_total;
3218
3219 /*
3220 * The monitoring pipe only holds messages smaller than PIPE_BUF,
3221 * ensuring that read/write of sampling messages are atomic.
3222 */
3223 ret = lttng_read(pipe, &sample_msg, sizeof(sample_msg));
3224 if (ret != sizeof(sample_msg)) {
3225 ERR("[notification-thread] Failed to read from monitoring pipe (fd = %i)",
3226 pipe);
3227 ret = -1;
3228 goto end;
3229 }
3230
3231 ret = 0;
3232 latest_sample.key.key = sample_msg.key;
3233 latest_sample.key.domain = domain;
3234 latest_sample.highest_usage = sample_msg.highest;
3235 latest_sample.lowest_usage = sample_msg.lowest;
3236 latest_sample.channel_total_consumed = sample_msg.total_consumed;
3237
3238 rcu_read_lock();
3239
3240 /* Retrieve the channel's informations */
3241 cds_lfht_lookup(state->channels_ht,
3242 hash_channel_key(&latest_sample.key),
3243 match_channel_info,
3244 &latest_sample.key,
3245 &iter);
3246 node = cds_lfht_iter_get_node(&iter);
3247 if (caa_unlikely(!node)) {
3248 /*
3249 * Not an error since the consumer can push a sample to the pipe
3250 * and the rest of the session daemon could notify us of the
3251 * channel's destruction before we get a chance to process that
3252 * sample.
3253 */
3254 DBG("[notification-thread] Received a sample for an unknown channel from consumerd, key = %" PRIu64 " in %s domain",
3255 latest_sample.key.key,
3256 domain == LTTNG_DOMAIN_KERNEL ? "kernel" :
3257 "user space");
3258 goto end_unlock;
3259 }
3260 channel_info = caa_container_of(node, struct channel_info,
3261 channels_ht_node);
3262 DBG("[notification-thread] Handling channel sample for channel %s (key = %" PRIu64 ") in session %s (highest usage = %" PRIu64 ", lowest usage = %" PRIu64", total consumed = %" PRIu64")",
3263 channel_info->name,
3264 latest_sample.key.key,
3265 channel_info->session_info->name,
3266 latest_sample.highest_usage,
3267 latest_sample.lowest_usage,
3268 latest_sample.channel_total_consumed);
3269
3270 previous_session_consumed_total =
3271 channel_info->session_info->consumed_data_size;
3272
3273 /* Retrieve the channel's last sample, if it exists, and update it. */
3274 cds_lfht_lookup(state->channel_state_ht,
3275 hash_channel_key(&latest_sample.key),
3276 match_channel_state_sample,
3277 &latest_sample.key,
3278 &iter);
3279 node = cds_lfht_iter_get_node(&iter);
3280 if (caa_likely(node)) {
3281 struct channel_state_sample *stored_sample;
3282
3283 /* Update the sample stored. */
3284 stored_sample = caa_container_of(node,
3285 struct channel_state_sample,
3286 channel_state_ht_node);
3287
3288 memcpy(&previous_sample, stored_sample,
3289 sizeof(previous_sample));
3290 stored_sample->highest_usage = latest_sample.highest_usage;
3291 stored_sample->lowest_usage = latest_sample.lowest_usage;
3292 stored_sample->channel_total_consumed = latest_sample.channel_total_consumed;
3293 previous_sample_available = true;
3294
3295 latest_session_consumed_total =
3296 previous_session_consumed_total +
3297 (latest_sample.channel_total_consumed - previous_sample.channel_total_consumed);
3298 } else {
3299 /*
3300 * This is the channel's first sample, allocate space for and
3301 * store the new sample.
3302 */
3303 struct channel_state_sample *stored_sample;
3304
3305 stored_sample = zmalloc(sizeof(*stored_sample));
3306 if (!stored_sample) {
3307 ret = -1;
3308 goto end_unlock;
3309 }
3310
3311 memcpy(stored_sample, &latest_sample, sizeof(*stored_sample));
3312 cds_lfht_node_init(&stored_sample->channel_state_ht_node);
3313 cds_lfht_add(state->channel_state_ht,
3314 hash_channel_key(&stored_sample->key),
3315 &stored_sample->channel_state_ht_node);
3316
3317 latest_session_consumed_total =
3318 previous_session_consumed_total +
3319 latest_sample.channel_total_consumed;
3320 }
3321
3322 channel_info->session_info->consumed_data_size =
3323 latest_session_consumed_total;
3324
3325 /* Find triggers associated with this channel. */
3326 cds_lfht_lookup(state->channel_triggers_ht,
3327 hash_channel_key(&latest_sample.key),
3328 match_channel_trigger_list,
3329 &latest_sample.key,
3330 &iter);
3331 node = cds_lfht_iter_get_node(&iter);
3332 if (caa_likely(!node)) {
3333 goto end_unlock;
3334 }
3335
3336 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
3337 channel_triggers_ht_node);
3338 cds_list_for_each_entry(trigger_list_element, &trigger_list->list,
3339 node) {
3340 const struct lttng_condition *condition;
3341 const struct lttng_action *action;
3342 const struct lttng_trigger *trigger;
3343 struct notification_client_list *client_list;
3344 struct lttng_evaluation *evaluation = NULL;
3345
3346 trigger = trigger_list_element->trigger;
3347 condition = lttng_trigger_get_const_condition(trigger);
3348 assert(condition);
3349 action = lttng_trigger_get_const_action(trigger);
3350
3351 /* Notify actions are the only type currently supported. */
3352 assert(lttng_action_get_type_const(action) ==
3353 LTTNG_ACTION_TYPE_NOTIFY);
3354
3355 /*
3356 * Check if any client is subscribed to the result of this
3357 * evaluation.
3358 */
3359 client_list = get_client_list_from_condition(state, condition);
3360 assert(client_list);
3361 if (cds_list_empty(&client_list->list)) {
3362 /*
3363 * No clients interested in the evaluation's result,
3364 * skip it.
3365 */
3366 continue;
3367 }
3368
3369 ret = evaluate_buffer_condition(condition, &evaluation, state,
3370 previous_sample_available ? &previous_sample : NULL,
3371 &latest_sample,
3372 previous_session_consumed_total,
3373 latest_session_consumed_total,
3374 channel_info);
3375 if (caa_unlikely(ret)) {
3376 goto end_unlock;
3377 }
3378
3379 if (caa_likely(!evaluation)) {
3380 continue;
3381 }
3382
3383 /* Dispatch evaluation result to all clients. */
3384 ret = send_evaluation_to_clients(trigger_list_element->trigger,
3385 evaluation, client_list, state,
3386 channel_info->session_info->uid,
3387 channel_info->session_info->gid);
3388 lttng_evaluation_destroy(evaluation);
3389 if (caa_unlikely(ret)) {
3390 goto end_unlock;
3391 }
3392 }
3393 end_unlock:
3394 rcu_read_unlock();
3395 end:
3396 return ret;
3397 }
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