Fix: error logged on partial recvmsg() in MSG_DONTWAIT
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-events.c
CommitLineData
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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
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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>
9b63a4aa 31#include <lttng/action/action-internal.h>
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32#include <lttng/notification/notification-internal.h>
33#include <lttng/condition/condition-internal.h>
34#include <lttng/condition/buffer-usage-internal.h>
e8360425 35#include <lttng/condition/session-consumed-size-internal.h>
ea9a44f0 36#include <lttng/condition/session-rotation-internal.h>
ab0ee2ca 37#include <lttng/notification/channel-internal.h>
1da26331 38
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39#include <time.h>
40#include <unistd.h>
41#include <assert.h>
42#include <inttypes.h>
d53ea4e4 43#include <fcntl.h>
ab0ee2ca 44
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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
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51#define CLIENT_POLL_MASK_IN (LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP)
52#define CLIENT_POLL_MASK_IN_OUT (CLIENT_POLL_MASK_IN | LPOLLOUT)
53
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54enum 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
ab0ee2ca 61struct lttng_trigger_list_element {
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62 /* No ownership of the trigger object is assumed. */
63 const struct lttng_trigger *trigger;
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64 struct cds_list_head node;
65};
66
67struct lttng_channel_trigger_list {
68 struct channel_key channel_key;
ea9a44f0 69 /* List of struct lttng_trigger_list_element. */
ab0ee2ca 70 struct cds_list_head list;
ea9a44f0 71 /* Node in the channel_triggers_ht */
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72 struct cds_lfht_node channel_triggers_ht_node;
73};
74
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75/*
76 * List of triggers applying to a given session.
77 *
78 * See:
79 * - lttng_session_trigger_list_create()
80 * - lttng_session_trigger_list_build()
81 * - lttng_session_trigger_list_destroy()
82 * - lttng_session_trigger_list_add()
83 */
84struct lttng_session_trigger_list {
85 /*
86 * Not owned by this; points to the session_info structure's
87 * session name.
88 */
89 const char *session_name;
90 /* List of struct lttng_trigger_list_element. */
91 struct cds_list_head list;
92 /* Node in the session_triggers_ht */
93 struct cds_lfht_node session_triggers_ht_node;
94 /*
95 * Weak reference to the notification system's session triggers
96 * hashtable.
97 *
98 * The session trigger list structure structure is owned by
99 * the session's session_info.
100 *
101 * The session_info is kept alive the the channel_infos holding a
102 * reference to it (reference counting). When those channels are
103 * destroyed (at runtime or on teardown), the reference they hold
104 * to the session_info are released. On destruction of session_info,
105 * session_info_destroy() will remove the list of triggers applying
106 * to this session from the notification system's state.
107 *
108 * This implies that the session_triggers_ht must be destroyed
109 * after the channels.
110 */
111 struct cds_lfht *session_triggers_ht;
112 /* Used for delayed RCU reclaim. */
113 struct rcu_head rcu_node;
114};
115
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116struct lttng_trigger_ht_element {
117 struct lttng_trigger *trigger;
118 struct cds_lfht_node node;
119};
120
121struct lttng_condition_list_element {
122 struct lttng_condition *condition;
123 struct cds_list_head node;
124};
125
126struct notification_client_list_element {
127 struct notification_client *client;
128 struct cds_list_head node;
129};
130
131struct notification_client_list {
f82f93a1 132 const struct lttng_trigger *trigger;
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133 struct cds_list_head list;
134 struct cds_lfht_node notification_trigger_ht_node;
135};
136
137struct notification_client {
138 int socket;
139 /* Client protocol version. */
140 uint8_t major, minor;
141 uid_t uid;
142 gid_t gid;
143 /*
5332364f 144 * Indicates if the credentials and versions of the client have been
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145 * checked.
146 */
147 bool validated;
148 /*
149 * Conditions to which the client's notification channel is subscribed.
150 * List of struct lttng_condition_list_node. The condition member is
151 * owned by the client.
152 */
153 struct cds_list_head condition_list;
154 struct cds_lfht_node client_socket_ht_node;
155 struct {
156 struct {
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157 /*
158 * During the reception of a message, the reception
159 * buffers' "size" is set to contain the current
160 * message's complete payload.
161 */
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162 struct lttng_dynamic_buffer buffer;
163 /* Bytes left to receive for the current message. */
164 size_t bytes_to_receive;
165 /* Type of the message being received. */
166 enum lttng_notification_channel_message_type msg_type;
167 /*
168 * Indicates whether or not credentials are expected
169 * from the client.
170 */
01ea340e 171 bool expect_creds;
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172 /*
173 * Indicates whether or not credentials were received
174 * from the client.
175 */
176 bool creds_received;
14fa22f8 177 /* Only used during credentials reception. */
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178 lttng_sock_cred creds;
179 } inbound;
180 struct {
181 /*
182 * Indicates whether or not a notification addressed to
183 * this client was dropped because a command reply was
184 * already buffered.
185 *
186 * A notification is dropped whenever the buffer is not
187 * empty.
188 */
189 bool dropped_notification;
190 /*
191 * Indicates whether or not a command reply is already
192 * buffered. In this case, it means that the client is
193 * not consuming command replies before emitting a new
194 * one. This could be caused by a protocol error or a
195 * misbehaving/malicious client.
196 */
197 bool queued_command_reply;
198 struct lttng_dynamic_buffer buffer;
199 } outbound;
200 } communication;
201};
202
203struct channel_state_sample {
204 struct channel_key key;
205 struct cds_lfht_node channel_state_ht_node;
206 uint64_t highest_usage;
207 uint64_t lowest_usage;
e8360425 208 uint64_t channel_total_consumed;
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209};
210
e4db5ace 211static unsigned long hash_channel_key(struct channel_key *key);
ed327204 212static int evaluate_buffer_condition(const struct lttng_condition *condition,
e4db5ace 213 struct lttng_evaluation **evaluation,
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214 const struct notification_thread_state *state,
215 const struct channel_state_sample *previous_sample,
216 const struct channel_state_sample *latest_sample,
217 uint64_t previous_session_consumed_total,
218 uint64_t latest_session_consumed_total,
219 struct channel_info *channel_info);
e4db5ace 220static
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221int send_evaluation_to_clients(const struct lttng_trigger *trigger,
222 const struct lttng_evaluation *evaluation,
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223 struct notification_client_list *client_list,
224 struct notification_thread_state *state,
225 uid_t channel_uid, gid_t channel_gid);
226
8abe313a 227
ea9a44f0 228/* session_info API */
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229static
230void session_info_destroy(void *_data);
231static
232void session_info_get(struct session_info *session_info);
233static
234void session_info_put(struct session_info *session_info);
235static
236struct session_info *session_info_create(const char *name,
ea9a44f0 237 uid_t uid, gid_t gid,
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238 struct lttng_session_trigger_list *trigger_list,
239 struct cds_lfht *sessions_ht);
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240static
241void session_info_add_channel(struct session_info *session_info,
242 struct channel_info *channel_info);
243static
244void session_info_remove_channel(struct session_info *session_info,
245 struct channel_info *channel_info);
246
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247/* lttng_session_trigger_list API */
248static
249struct lttng_session_trigger_list *lttng_session_trigger_list_create(
250 const char *session_name,
251 struct cds_lfht *session_triggers_ht);
252static
253struct lttng_session_trigger_list *lttng_session_trigger_list_build(
254 const struct notification_thread_state *state,
255 const char *session_name);
256static
257void lttng_session_trigger_list_destroy(
258 struct lttng_session_trigger_list *list);
259static
260int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list,
261 const struct lttng_trigger *trigger);
262
263
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264static
265int match_client(struct cds_lfht_node *node, const void *key)
266{
267 /* This double-cast is intended to supress pointer-to-cast warning. */
268 int socket = (int) (intptr_t) key;
269 struct notification_client *client;
270
271 client = caa_container_of(node, struct notification_client,
272 client_socket_ht_node);
273
274 return !!(client->socket == socket);
275}
276
277static
278int match_channel_trigger_list(struct cds_lfht_node *node, const void *key)
279{
280 struct channel_key *channel_key = (struct channel_key *) key;
281 struct lttng_channel_trigger_list *trigger_list;
282
283 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
284 channel_triggers_ht_node);
285
286 return !!((channel_key->key == trigger_list->channel_key.key) &&
287 (channel_key->domain == trigger_list->channel_key.domain));
288}
289
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290static
291int match_session_trigger_list(struct cds_lfht_node *node, const void *key)
292{
293 const char *session_name = (const char *) key;
294 struct lttng_session_trigger_list *trigger_list;
295
296 trigger_list = caa_container_of(node, struct lttng_session_trigger_list,
297 session_triggers_ht_node);
298
299 return !!(strcmp(trigger_list->session_name, session_name) == 0);
300}
301
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302static
303int match_channel_state_sample(struct cds_lfht_node *node, const void *key)
304{
305 struct channel_key *channel_key = (struct channel_key *) key;
306 struct channel_state_sample *sample;
307
308 sample = caa_container_of(node, struct channel_state_sample,
309 channel_state_ht_node);
310
311 return !!((channel_key->key == sample->key.key) &&
312 (channel_key->domain == sample->key.domain));
313}
314
315static
316int match_channel_info(struct cds_lfht_node *node, const void *key)
317{
318 struct channel_key *channel_key = (struct channel_key *) key;
319 struct channel_info *channel_info;
320
321 channel_info = caa_container_of(node, struct channel_info,
322 channels_ht_node);
323
324 return !!((channel_key->key == channel_info->key.key) &&
325 (channel_key->domain == channel_info->key.domain));
326}
327
328static
329int match_condition(struct cds_lfht_node *node, const void *key)
330{
331 struct lttng_condition *condition_key = (struct lttng_condition *) key;
332 struct lttng_trigger_ht_element *trigger;
333 struct lttng_condition *condition;
334
335 trigger = caa_container_of(node, struct lttng_trigger_ht_element,
336 node);
337 condition = lttng_trigger_get_condition(trigger->trigger);
338 assert(condition);
339
340 return !!lttng_condition_is_equal(condition_key, condition);
341}
342
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343static
344int match_client_list_condition(struct cds_lfht_node *node, const void *key)
345{
346 struct lttng_condition *condition_key = (struct lttng_condition *) key;
347 struct notification_client_list *client_list;
f82f93a1 348 const struct lttng_condition *condition;
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349
350 assert(condition_key);
351
352 client_list = caa_container_of(node, struct notification_client_list,
353 notification_trigger_ht_node);
f82f93a1 354 condition = lttng_trigger_get_const_condition(client_list->trigger);
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355
356 return !!lttng_condition_is_equal(condition_key, condition);
357}
358
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359static
360int match_session(struct cds_lfht_node *node, const void *key)
361{
362 const char *name = key;
363 struct session_info *session_info = caa_container_of(
364 node, struct session_info, sessions_ht_node);
365
366 return !strcmp(session_info->name, name);
367}
368
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369static
370unsigned long lttng_condition_buffer_usage_hash(
9b63a4aa 371 const struct lttng_condition *_condition)
ab0ee2ca 372{
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373 unsigned long hash;
374 unsigned long condition_type;
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375 struct lttng_condition_buffer_usage *condition;
376
377 condition = container_of(_condition,
378 struct lttng_condition_buffer_usage, parent);
379
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380 condition_type = (unsigned long) condition->parent.type;
381 hash = hash_key_ulong((void *) condition_type, lttng_ht_seed);
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382 if (condition->session_name) {
383 hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
384 }
385 if (condition->channel_name) {
8f56701f 386 hash ^= hash_key_str(condition->channel_name, lttng_ht_seed);
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387 }
388 if (condition->domain.set) {
389 hash ^= hash_key_ulong(
390 (void *) condition->domain.type,
391 lttng_ht_seed);
392 }
393 if (condition->threshold_ratio.set) {
394 uint64_t val;
395
396 val = condition->threshold_ratio.value * (double) UINT32_MAX;
397 hash ^= hash_key_u64(&val, lttng_ht_seed);
6633b0dd 398 } else if (condition->threshold_bytes.set) {
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399 uint64_t val;
400
401 val = condition->threshold_bytes.value;
402 hash ^= hash_key_u64(&val, lttng_ht_seed);
403 }
404 return hash;
405}
406
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407static
408unsigned long lttng_condition_session_consumed_size_hash(
9b63a4aa 409 const struct lttng_condition *_condition)
e8360425 410{
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411 unsigned long hash;
412 unsigned long condition_type =
413 (unsigned long) LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE;
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414 struct lttng_condition_session_consumed_size *condition;
415 uint64_t val;
416
417 condition = container_of(_condition,
418 struct lttng_condition_session_consumed_size, parent);
419
9a2746aa 420 hash = hash_key_ulong((void *) condition_type, lttng_ht_seed);
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421 if (condition->session_name) {
422 hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
423 }
424 val = condition->consumed_threshold_bytes.value;
425 hash ^= hash_key_u64(&val, lttng_ht_seed);
426 return hash;
427}
428
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429static
430unsigned long lttng_condition_session_rotation_hash(
431 const struct lttng_condition *_condition)
432{
433 unsigned long hash, condition_type;
434 struct lttng_condition_session_rotation *condition;
435
436 condition = container_of(_condition,
437 struct lttng_condition_session_rotation, parent);
438 condition_type = (unsigned long) condition->parent.type;
439 hash = hash_key_ulong((void *) condition_type, lttng_ht_seed);
440 assert(condition->session_name);
441 hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
442 return hash;
443}
9a2746aa 444
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445/*
446 * The lttng_condition hashing code is kept in this file (rather than
447 * condition.c) since it makes use of GPLv2 code (hashtable utils), which we
448 * don't want to link in liblttng-ctl.
449 */
450static
9b63a4aa 451unsigned long lttng_condition_hash(const struct lttng_condition *condition)
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452{
453 switch (condition->type) {
454 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
455 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
456 return lttng_condition_buffer_usage_hash(condition);
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457 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
458 return lttng_condition_session_consumed_size_hash(condition);
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459 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
460 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
461 return lttng_condition_session_rotation_hash(condition);
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462 default:
463 ERR("[notification-thread] Unexpected condition type caught");
464 abort();
465 }
466}
467
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468static
469unsigned long hash_channel_key(struct channel_key *key)
470{
471 unsigned long key_hash = hash_key_u64(&key->key, lttng_ht_seed);
472 unsigned long domain_hash = hash_key_ulong(
473 (void *) (unsigned long) key->domain, lttng_ht_seed);
474
475 return key_hash ^ domain_hash;
476}
477
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478/*
479 * Get the type of object to which a given condition applies. Bindings let
480 * the notification system evaluate a trigger's condition when a given
481 * object's state is updated.
482 *
483 * For instance, a condition bound to a channel will be evaluated everytime
484 * the channel's state is changed by a channel monitoring sample.
485 */
486static
487enum lttng_object_type get_condition_binding_object(
488 const struct lttng_condition *condition)
489{
490 switch (lttng_condition_get_type(condition)) {
491 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
492 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
493 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
494 return LTTNG_OBJECT_TYPE_CHANNEL;
495 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
496 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
497 return LTTNG_OBJECT_TYPE_SESSION;
498 default:
499 return LTTNG_OBJECT_TYPE_UNKNOWN;
500 }
501}
502
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503static
504void channel_info_destroy(struct channel_info *channel_info)
505{
506 if (!channel_info) {
507 return;
508 }
509
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510 if (channel_info->session_info) {
511 session_info_remove_channel(channel_info->session_info,
512 channel_info);
513 session_info_put(channel_info->session_info);
ab0ee2ca 514 }
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515 if (channel_info->name) {
516 free(channel_info->name);
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517 }
518 free(channel_info);
519}
520
8abe313a 521/* Don't call directly, use the ref-counting mechanism. */
ab0ee2ca 522static
8abe313a 523void session_info_destroy(void *_data)
ab0ee2ca 524{
8abe313a 525 struct session_info *session_info = _data;
3b68d0a3 526 int ret;
ab0ee2ca 527
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528 assert(session_info);
529 if (session_info->channel_infos_ht) {
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530 ret = cds_lfht_destroy(session_info->channel_infos_ht, NULL);
531 if (ret) {
4c3f302b 532 ERR("[notification-thread] Failed to destroy channel information hash table");
3b68d0a3 533 }
8abe313a 534 }
ea9a44f0 535 lttng_session_trigger_list_destroy(session_info->trigger_list);
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536
537 rcu_read_lock();
538 cds_lfht_del(session_info->sessions_ht,
539 &session_info->sessions_ht_node);
540 rcu_read_unlock();
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541 free(session_info->name);
542 free(session_info);
543}
ab0ee2ca 544
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545static
546void session_info_get(struct session_info *session_info)
547{
548 if (!session_info) {
549 return;
550 }
551 lttng_ref_get(&session_info->ref);
552}
553
554static
555void session_info_put(struct session_info *session_info)
556{
557 if (!session_info) {
558 return;
ab0ee2ca 559 }
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560 lttng_ref_put(&session_info->ref);
561}
562
563static
ea9a44f0 564struct session_info *session_info_create(const char *name, uid_t uid, gid_t gid,
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565 struct lttng_session_trigger_list *trigger_list,
566 struct cds_lfht *sessions_ht)
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567{
568 struct session_info *session_info;
ab0ee2ca 569
8abe313a 570 assert(name);
ab0ee2ca 571
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572 session_info = zmalloc(sizeof(*session_info));
573 if (!session_info) {
574 goto end;
575 }
576 lttng_ref_init(&session_info->ref, session_info_destroy);
577
578 session_info->channel_infos_ht = cds_lfht_new(DEFAULT_HT_SIZE,
579 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
580 if (!session_info->channel_infos_ht) {
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581 goto error;
582 }
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583
584 cds_lfht_node_init(&session_info->sessions_ht_node);
585 session_info->name = strdup(name);
586 if (!session_info->name) {
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587 goto error;
588 }
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589 session_info->uid = uid;
590 session_info->gid = gid;
ea9a44f0 591 session_info->trigger_list = trigger_list;
1eee26c5 592 session_info->sessions_ht = sessions_ht;
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593end:
594 return session_info;
595error:
596 session_info_put(session_info);
597 return NULL;
598}
599
600static
601void session_info_add_channel(struct session_info *session_info,
602 struct channel_info *channel_info)
603{
604 rcu_read_lock();
605 cds_lfht_add(session_info->channel_infos_ht,
606 hash_channel_key(&channel_info->key),
607 &channel_info->session_info_channels_ht_node);
608 rcu_read_unlock();
609}
610
611static
612void session_info_remove_channel(struct session_info *session_info,
613 struct channel_info *channel_info)
614{
615 rcu_read_lock();
616 cds_lfht_del(session_info->channel_infos_ht,
617 &channel_info->session_info_channels_ht_node);
618 rcu_read_unlock();
619}
620
621static
622struct channel_info *channel_info_create(const char *channel_name,
623 struct channel_key *channel_key, uint64_t channel_capacity,
624 struct session_info *session_info)
625{
626 struct channel_info *channel_info = zmalloc(sizeof(*channel_info));
627
628 if (!channel_info) {
629 goto end;
630 }
631
ab0ee2ca 632 cds_lfht_node_init(&channel_info->channels_ht_node);
8abe313a
JG
633 cds_lfht_node_init(&channel_info->session_info_channels_ht_node);
634 memcpy(&channel_info->key, channel_key, sizeof(*channel_key));
635 channel_info->capacity = channel_capacity;
636
637 channel_info->name = strdup(channel_name);
638 if (!channel_info->name) {
639 goto error;
640 }
641
642 /*
643 * Set the references between session and channel infos:
644 * - channel_info holds a strong reference to session_info
645 * - session_info holds a weak reference to channel_info
646 */
647 session_info_get(session_info);
648 session_info_add_channel(session_info, channel_info);
649 channel_info->session_info = session_info;
ab0ee2ca 650end:
8abe313a 651 return channel_info;
ab0ee2ca 652error:
8abe313a 653 channel_info_destroy(channel_info);
ab0ee2ca
JG
654 return NULL;
655}
656
ed327204
JG
657/* RCU read lock must be held by the caller. */
658static
659struct notification_client_list *get_client_list_from_condition(
660 struct notification_thread_state *state,
661 const struct lttng_condition *condition)
662{
663 struct cds_lfht_node *node;
664 struct cds_lfht_iter iter;
665
666 cds_lfht_lookup(state->notification_trigger_clients_ht,
667 lttng_condition_hash(condition),
668 match_client_list_condition,
669 condition,
670 &iter);
671 node = cds_lfht_iter_get_node(&iter);
672
673 return node ? caa_container_of(node,
674 struct notification_client_list,
675 notification_trigger_ht_node) : NULL;
676}
677
e4db5ace
JR
678/* This function must be called with the RCU read lock held. */
679static
f82f93a1
JG
680int evaluate_channel_condition_for_client(
681 const struct lttng_condition *condition,
682 struct notification_thread_state *state,
683 struct lttng_evaluation **evaluation,
684 uid_t *session_uid, gid_t *session_gid)
e4db5ace
JR
685{
686 int ret;
687 struct cds_lfht_iter iter;
688 struct cds_lfht_node *node;
689 struct channel_info *channel_info = NULL;
690 struct channel_key *channel_key = NULL;
691 struct channel_state_sample *last_sample = NULL;
692 struct lttng_channel_trigger_list *channel_trigger_list = NULL;
e4db5ace 693
f82f93a1 694 /* Find the channel associated with the condition. */
e4db5ace 695 cds_lfht_for_each_entry(state->channel_triggers_ht, &iter,
f82f93a1 696 channel_trigger_list, channel_triggers_ht_node) {
e4db5ace
JR
697 struct lttng_trigger_list_element *element;
698
699 cds_list_for_each_entry(element, &channel_trigger_list->list, node) {
9b63a4aa 700 const struct lttng_condition *current_condition =
f82f93a1 701 lttng_trigger_get_const_condition(
e4db5ace
JR
702 element->trigger);
703
704 assert(current_condition);
705 if (!lttng_condition_is_equal(condition,
2ae99f0b 706 current_condition)) {
e4db5ace
JR
707 continue;
708 }
709
710 /* Found the trigger, save the channel key. */
711 channel_key = &channel_trigger_list->channel_key;
712 break;
713 }
714 if (channel_key) {
715 /* The channel key was found stop iteration. */
716 break;
717 }
718 }
719
720 if (!channel_key){
721 /* No channel found; normal exit. */
f82f93a1 722 DBG("[notification-thread] No known channel associated with newly subscribed-to condition");
e4db5ace
JR
723 ret = 0;
724 goto end;
725 }
726
727 /* Fetch channel info for the matching channel. */
728 cds_lfht_lookup(state->channels_ht,
729 hash_channel_key(channel_key),
730 match_channel_info,
731 channel_key,
732 &iter);
733 node = cds_lfht_iter_get_node(&iter);
734 assert(node);
735 channel_info = caa_container_of(node, struct channel_info,
736 channels_ht_node);
737
738 /* Retrieve the channel's last sample, if it exists. */
739 cds_lfht_lookup(state->channel_state_ht,
740 hash_channel_key(channel_key),
741 match_channel_state_sample,
742 channel_key,
743 &iter);
744 node = cds_lfht_iter_get_node(&iter);
745 if (node) {
746 last_sample = caa_container_of(node,
747 struct channel_state_sample,
748 channel_state_ht_node);
749 } else {
750 /* Nothing to evaluate, no sample was ever taken. Normal exit */
751 DBG("[notification-thread] No channel sample associated with newly subscribed-to condition");
752 ret = 0;
753 goto end;
754 }
755
f82f93a1 756 ret = evaluate_buffer_condition(condition, evaluation, state,
e8360425
JD
757 NULL, last_sample,
758 0, channel_info->session_info->consumed_data_size,
759 channel_info);
e4db5ace 760 if (ret) {
066a3c82 761 WARN("[notification-thread] Fatal error occurred while evaluating a newly subscribed-to condition");
e4db5ace
JR
762 goto end;
763 }
764
f82f93a1
JG
765 *session_uid = channel_info->session_info->uid;
766 *session_gid = channel_info->session_info->gid;
767end:
768 return ret;
769}
770
771static
772const char *get_condition_session_name(const struct lttng_condition *condition)
773{
774 const char *session_name = NULL;
775 enum lttng_condition_status status;
776
777 switch (lttng_condition_get_type(condition)) {
778 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
779 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
780 status = lttng_condition_buffer_usage_get_session_name(
781 condition, &session_name);
782 break;
783 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
784 status = lttng_condition_session_consumed_size_get_session_name(
785 condition, &session_name);
786 break;
787 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
788 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
789 status = lttng_condition_session_rotation_get_session_name(
790 condition, &session_name);
791 break;
792 default:
793 abort();
794 }
795 if (status != LTTNG_CONDITION_STATUS_OK) {
796 ERR("[notification-thread] Failed to retrieve session rotation condition's session name");
797 goto end;
798 }
799end:
800 return session_name;
801}
802
803/* This function must be called with the RCU read lock held. */
804static
805int evaluate_session_condition_for_client(
806 const struct lttng_condition *condition,
807 struct notification_thread_state *state,
808 struct lttng_evaluation **evaluation,
809 uid_t *session_uid, gid_t *session_gid)
810{
811 int ret;
812 struct cds_lfht_iter iter;
813 struct cds_lfht_node *node;
814 const char *session_name;
815 struct session_info *session_info = NULL;
816
817 session_name = get_condition_session_name(condition);
818
819 /* Find the session associated with the trigger. */
820 cds_lfht_lookup(state->sessions_ht,
821 hash_key_str(session_name, lttng_ht_seed),
822 match_session,
823 session_name,
824 &iter);
825 node = cds_lfht_iter_get_node(&iter);
826 if (!node) {
827 DBG("[notification-thread] No known session matching name \"%s\"",
828 session_name);
829 ret = 0;
830 goto end;
831 }
832
833 session_info = caa_container_of(node, struct session_info,
834 sessions_ht_node);
835 session_info_get(session_info);
836
837 /*
838 * Evaluation is performed in-line here since only one type of
839 * session-bound condition is handled for the moment.
840 */
841 switch (lttng_condition_get_type(condition)) {
842 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
843 if (!session_info->rotation.ongoing) {
be558f88 844 ret = 0;
f82f93a1
JG
845 goto end_session_put;
846 }
847
848 *evaluation = lttng_evaluation_session_rotation_ongoing_create(
849 session_info->rotation.id);
850 if (!*evaluation) {
851 /* Fatal error. */
852 ERR("[notification-thread] Failed to create session rotation ongoing evaluation for session \"%s\"",
853 session_info->name);
854 ret = -1;
855 goto end_session_put;
856 }
857 ret = 0;
858 break;
859 default:
860 ret = 0;
861 goto end_session_put;
862 }
863
864 *session_uid = session_info->uid;
865 *session_gid = session_info->gid;
866
867end_session_put:
868 session_info_put(session_info);
869end:
870 return ret;
871}
872
873/* This function must be called with the RCU read lock held. */
874static
875int evaluate_condition_for_client(const struct lttng_trigger *trigger,
876 const struct lttng_condition *condition,
877 struct notification_client *client,
878 struct notification_thread_state *state)
879{
880 int ret;
881 struct lttng_evaluation *evaluation = NULL;
882 struct notification_client_list client_list = { 0 };
883 struct notification_client_list_element client_list_element = { 0 };
884 uid_t object_uid = 0;
885 gid_t object_gid = 0;
886
887 assert(trigger);
888 assert(condition);
889 assert(client);
890 assert(state);
891
892 switch (get_condition_binding_object(condition)) {
893 case LTTNG_OBJECT_TYPE_SESSION:
894 ret = evaluate_session_condition_for_client(condition, state,
895 &evaluation, &object_uid, &object_gid);
896 break;
897 case LTTNG_OBJECT_TYPE_CHANNEL:
898 ret = evaluate_channel_condition_for_client(condition, state,
899 &evaluation, &object_uid, &object_gid);
900 break;
901 case LTTNG_OBJECT_TYPE_NONE:
902 ret = 0;
903 goto end;
904 case LTTNG_OBJECT_TYPE_UNKNOWN:
905 default:
906 ret = -1;
907 goto end;
908 }
909
e4db5ace
JR
910 if (!evaluation) {
911 /* Evaluation yielded nothing. Normal exit. */
912 DBG("[notification-thread] Newly subscribed-to condition evaluated to false, nothing to report to client");
913 ret = 0;
914 goto end;
915 }
916
917 /*
918 * Create a temporary client list with the client currently
919 * subscribing.
920 */
921 cds_lfht_node_init(&client_list.notification_trigger_ht_node);
922 CDS_INIT_LIST_HEAD(&client_list.list);
923 client_list.trigger = trigger;
924
925 CDS_INIT_LIST_HEAD(&client_list_element.node);
926 client_list_element.client = client;
927 cds_list_add(&client_list_element.node, &client_list.list);
928
929 /* Send evaluation result to the newly-subscribed client. */
930 DBG("[notification-thread] Newly subscribed-to condition evaluated to true, notifying client");
931 ret = send_evaluation_to_clients(trigger, evaluation, &client_list,
f82f93a1 932 state, object_uid, object_gid);
e4db5ace
JR
933
934end:
935 return ret;
936}
937
ab0ee2ca
JG
938static
939int notification_thread_client_subscribe(struct notification_client *client,
940 struct lttng_condition *condition,
941 struct notification_thread_state *state,
942 enum lttng_notification_channel_status *_status)
943{
944 int ret = 0;
ab0ee2ca
JG
945 struct notification_client_list *client_list;
946 struct lttng_condition_list_element *condition_list_element = NULL;
947 struct notification_client_list_element *client_list_element = NULL;
948 enum lttng_notification_channel_status status =
949 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
950
951 /*
952 * Ensure that the client has not already subscribed to this condition
953 * before.
954 */
955 cds_list_for_each_entry(condition_list_element, &client->condition_list, node) {
956 if (lttng_condition_is_equal(condition_list_element->condition,
957 condition)) {
958 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ALREADY_SUBSCRIBED;
959 goto end;
960 }
961 }
962
963 condition_list_element = zmalloc(sizeof(*condition_list_element));
964 if (!condition_list_element) {
965 ret = -1;
966 goto error;
967 }
968 client_list_element = zmalloc(sizeof(*client_list_element));
969 if (!client_list_element) {
970 ret = -1;
971 goto error;
972 }
973
974 rcu_read_lock();
975
976 /*
977 * Add the newly-subscribed condition to the client's subscription list.
978 */
979 CDS_INIT_LIST_HEAD(&condition_list_element->node);
980 condition_list_element->condition = condition;
981 cds_list_add(&condition_list_element->node, &client->condition_list);
982
ed327204
JG
983 client_list = get_client_list_from_condition(state, condition);
984 if (!client_list) {
2ae99f0b
JG
985 /*
986 * No notification-emiting trigger registered with this
987 * condition. We don't evaluate the condition right away
988 * since this trigger is not registered yet.
989 */
4fb43b68 990 free(client_list_element);
ab0ee2ca
JG
991 goto end_unlock;
992 }
993
2ae99f0b
JG
994 /*
995 * The condition to which the client just subscribed is evaluated
996 * at this point so that conditions that are already TRUE result
997 * in a notification being sent out.
998 */
e4db5ace
JR
999 if (evaluate_condition_for_client(client_list->trigger, condition,
1000 client, state)) {
1001 WARN("[notification-thread] Evaluation of a condition on client subscription failed, aborting.");
1002 ret = -1;
4bd5b4af 1003 free(client_list_element);
e4db5ace
JR
1004 goto end_unlock;
1005 }
1006
1007 /*
1008 * Add the client to the list of clients interested in a given trigger
1009 * if a "notification" trigger with a corresponding condition was
1010 * added prior.
1011 */
ab0ee2ca
JG
1012 client_list_element->client = client;
1013 CDS_INIT_LIST_HEAD(&client_list_element->node);
1014 cds_list_add(&client_list_element->node, &client_list->list);
1015end_unlock:
1016 rcu_read_unlock();
1017end:
1018 if (_status) {
1019 *_status = status;
1020 }
1021 return ret;
1022error:
1023 free(condition_list_element);
1024 free(client_list_element);
1025 return ret;
1026}
1027
1028static
1029int notification_thread_client_unsubscribe(
1030 struct notification_client *client,
1031 struct lttng_condition *condition,
1032 struct notification_thread_state *state,
1033 enum lttng_notification_channel_status *_status)
1034{
ab0ee2ca
JG
1035 struct notification_client_list *client_list;
1036 struct lttng_condition_list_element *condition_list_element,
1037 *condition_tmp;
1038 struct notification_client_list_element *client_list_element,
1039 *client_tmp;
1040 bool condition_found = false;
1041 enum lttng_notification_channel_status status =
1042 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
1043
1044 /* Remove the condition from the client's condition list. */
1045 cds_list_for_each_entry_safe(condition_list_element, condition_tmp,
1046 &client->condition_list, node) {
1047 if (!lttng_condition_is_equal(condition_list_element->condition,
1048 condition)) {
1049 continue;
1050 }
1051
1052 cds_list_del(&condition_list_element->node);
1053 /*
1054 * The caller may be iterating on the client's conditions to
1055 * tear down a client's connection. In this case, the condition
1056 * will be destroyed at the end.
1057 */
1058 if (condition != condition_list_element->condition) {
1059 lttng_condition_destroy(
1060 condition_list_element->condition);
1061 }
1062 free(condition_list_element);
1063 condition_found = true;
1064 break;
1065 }
1066
1067 if (!condition_found) {
1068 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNKNOWN_CONDITION;
1069 goto end;
1070 }
1071
1072 /*
1073 * Remove the client from the list of clients interested the trigger
1074 * matching the condition.
1075 */
1076 rcu_read_lock();
ed327204
JG
1077 client_list = get_client_list_from_condition(state, condition);
1078 if (!client_list) {
ab0ee2ca
JG
1079 goto end_unlock;
1080 }
1081
ab0ee2ca
JG
1082 cds_list_for_each_entry_safe(client_list_element, client_tmp,
1083 &client_list->list, node) {
1084 if (client_list_element->client->socket != client->socket) {
1085 continue;
1086 }
1087 cds_list_del(&client_list_element->node);
1088 free(client_list_element);
1089 break;
1090 }
1091end_unlock:
1092 rcu_read_unlock();
1093end:
1094 lttng_condition_destroy(condition);
1095 if (_status) {
1096 *_status = status;
1097 }
1098 return 0;
1099}
1100
1101static
1102void notification_client_destroy(struct notification_client *client,
1103 struct notification_thread_state *state)
1104{
1105 struct lttng_condition_list_element *condition_list_element, *tmp;
1106
1107 if (!client) {
1108 return;
1109 }
1110
1111 /* Release all conditions to which the client was subscribed. */
1112 cds_list_for_each_entry_safe(condition_list_element, tmp,
1113 &client->condition_list, node) {
1114 (void) notification_thread_client_unsubscribe(client,
1115 condition_list_element->condition, state, NULL);
1116 }
1117
1118 if (client->socket >= 0) {
1119 (void) lttcomm_close_unix_sock(client->socket);
1120 }
1121 lttng_dynamic_buffer_reset(&client->communication.inbound.buffer);
1122 lttng_dynamic_buffer_reset(&client->communication.outbound.buffer);
1123 free(client);
1124}
1125
1126/*
1127 * Call with rcu_read_lock held (and hold for the lifetime of the returned
1128 * client pointer).
1129 */
1130static
1131struct notification_client *get_client_from_socket(int socket,
1132 struct notification_thread_state *state)
1133{
1134 struct cds_lfht_iter iter;
1135 struct cds_lfht_node *node;
1136 struct notification_client *client = NULL;
1137
1138 cds_lfht_lookup(state->client_socket_ht,
1139 hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed),
1140 match_client,
1141 (void *) (unsigned long) socket,
1142 &iter);
1143 node = cds_lfht_iter_get_node(&iter);
1144 if (!node) {
1145 goto end;
1146 }
1147
1148 client = caa_container_of(node, struct notification_client,
1149 client_socket_ht_node);
1150end:
1151 return client;
1152}
1153
1154static
e8360425 1155bool buffer_usage_condition_applies_to_channel(
51eab943
JG
1156 const struct lttng_condition *condition,
1157 const struct channel_info *channel_info)
ab0ee2ca
JG
1158{
1159 enum lttng_condition_status status;
e8360425
JD
1160 enum lttng_domain_type condition_domain;
1161 const char *condition_session_name = NULL;
1162 const char *condition_channel_name = NULL;
ab0ee2ca 1163
e8360425
JD
1164 status = lttng_condition_buffer_usage_get_domain_type(condition,
1165 &condition_domain);
1166 assert(status == LTTNG_CONDITION_STATUS_OK);
1167 if (channel_info->key.domain != condition_domain) {
ab0ee2ca
JG
1168 goto fail;
1169 }
1170
e8360425
JD
1171 status = lttng_condition_buffer_usage_get_session_name(
1172 condition, &condition_session_name);
1173 assert((status == LTTNG_CONDITION_STATUS_OK) && condition_session_name);
1174
1175 status = lttng_condition_buffer_usage_get_channel_name(
1176 condition, &condition_channel_name);
1177 assert((status == LTTNG_CONDITION_STATUS_OK) && condition_channel_name);
1178
1179 if (strcmp(channel_info->session_info->name, condition_session_name)) {
1180 goto fail;
1181 }
1182 if (strcmp(channel_info->name, condition_channel_name)) {
ab0ee2ca
JG
1183 goto fail;
1184 }
1185
e8360425
JD
1186 return true;
1187fail:
1188 return false;
1189}
1190
1191static
1192bool session_consumed_size_condition_applies_to_channel(
51eab943
JG
1193 const struct lttng_condition *condition,
1194 const struct channel_info *channel_info)
e8360425
JD
1195{
1196 enum lttng_condition_status status;
1197 const char *condition_session_name = NULL;
1198
1199 status = lttng_condition_session_consumed_size_get_session_name(
1200 condition, &condition_session_name);
1201 assert((status == LTTNG_CONDITION_STATUS_OK) && condition_session_name);
1202
1203 if (strcmp(channel_info->session_info->name, condition_session_name)) {
ab0ee2ca
JG
1204 goto fail;
1205 }
1206
e8360425
JD
1207 return true;
1208fail:
1209 return false;
1210}
ab0ee2ca 1211
51eab943
JG
1212static
1213bool trigger_applies_to_channel(const struct lttng_trigger *trigger,
1214 const struct channel_info *channel_info)
1215{
1216 const struct lttng_condition *condition;
e8360425 1217 bool trigger_applies;
ab0ee2ca 1218
51eab943 1219 condition = lttng_trigger_get_const_condition(trigger);
e8360425 1220 if (!condition) {
ab0ee2ca
JG
1221 goto fail;
1222 }
e8360425
JD
1223
1224 switch (lttng_condition_get_type(condition)) {
1225 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
1226 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
1227 trigger_applies = buffer_usage_condition_applies_to_channel(
1228 condition, channel_info);
1229 break;
1230 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
1231 trigger_applies = session_consumed_size_condition_applies_to_channel(
1232 condition, channel_info);
1233 break;
1234 default:
ab0ee2ca
JG
1235 goto fail;
1236 }
1237
e8360425 1238 return trigger_applies;
ab0ee2ca
JG
1239fail:
1240 return false;
1241}
1242
1243static
1244bool trigger_applies_to_client(struct lttng_trigger *trigger,
1245 struct notification_client *client)
1246{
1247 bool applies = false;
1248 struct lttng_condition_list_element *condition_list_element;
1249
1250 cds_list_for_each_entry(condition_list_element, &client->condition_list,
1251 node) {
1252 applies = lttng_condition_is_equal(
1253 condition_list_element->condition,
1254 lttng_trigger_get_condition(trigger));
1255 if (applies) {
1256 break;
1257 }
1258 }
1259 return applies;
1260}
1261
ed327204
JG
1262/* Must be called with RCU read lock held. */
1263static
1264struct lttng_session_trigger_list *get_session_trigger_list(
1265 struct notification_thread_state *state,
1266 const char *session_name)
1267{
1268 struct lttng_session_trigger_list *list = NULL;
1269 struct cds_lfht_node *node;
1270 struct cds_lfht_iter iter;
1271
1272 cds_lfht_lookup(state->session_triggers_ht,
1273 hash_key_str(session_name, lttng_ht_seed),
1274 match_session_trigger_list,
1275 session_name,
1276 &iter);
1277 node = cds_lfht_iter_get_node(&iter);
1278 if (!node) {
1279 /*
1280 * Not an error, the list of triggers applying to that session
1281 * will be initialized when the session is created.
1282 */
1283 DBG("[notification-thread] No trigger list found for session \"%s\" as it is not yet known to the notification system",
1284 session_name);
1285 goto end;
1286 }
1287
1288 list = caa_container_of(node,
1289 struct lttng_session_trigger_list,
1290 session_triggers_ht_node);
1291end:
1292 return list;
1293}
1294
ea9a44f0
JG
1295/*
1296 * Allocate an empty lttng_session_trigger_list for the session named
1297 * 'session_name'.
1298 *
1299 * No ownership of 'session_name' is assumed by the session trigger list.
1300 * It is the caller's responsability to ensure the session name is alive
1301 * for as long as this list is.
1302 */
1303static
1304struct lttng_session_trigger_list *lttng_session_trigger_list_create(
1305 const char *session_name,
1306 struct cds_lfht *session_triggers_ht)
1307{
1308 struct lttng_session_trigger_list *list;
1309
1310 list = zmalloc(sizeof(*list));
1311 if (!list) {
1312 goto end;
1313 }
1314 list->session_name = session_name;
1315 CDS_INIT_LIST_HEAD(&list->list);
1316 cds_lfht_node_init(&list->session_triggers_ht_node);
1317 list->session_triggers_ht = session_triggers_ht;
1318
1319 rcu_read_lock();
1320 /* Publish the list through the session_triggers_ht. */
1321 cds_lfht_add(session_triggers_ht,
1322 hash_key_str(session_name, lttng_ht_seed),
1323 &list->session_triggers_ht_node);
1324 rcu_read_unlock();
1325end:
1326 return list;
1327}
1328
1329static
1330void free_session_trigger_list_rcu(struct rcu_head *node)
1331{
1332 free(caa_container_of(node, struct lttng_session_trigger_list,
1333 rcu_node));
1334}
1335
1336static
1337void lttng_session_trigger_list_destroy(struct lttng_session_trigger_list *list)
1338{
1339 struct lttng_trigger_list_element *trigger_list_element, *tmp;
1340
1341 /* Empty the list element by element, and then free the list itself. */
1342 cds_list_for_each_entry_safe(trigger_list_element, tmp,
1343 &list->list, node) {
1344 cds_list_del(&trigger_list_element->node);
1345 free(trigger_list_element);
1346 }
1347 rcu_read_lock();
1348 /* Unpublish the list from the session_triggers_ht. */
1349 cds_lfht_del(list->session_triggers_ht,
1350 &list->session_triggers_ht_node);
1351 rcu_read_unlock();
1352 call_rcu(&list->rcu_node, free_session_trigger_list_rcu);
1353}
1354
1355static
1356int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list,
1357 const struct lttng_trigger *trigger)
1358{
1359 int ret = 0;
1360 struct lttng_trigger_list_element *new_element =
1361 zmalloc(sizeof(*new_element));
1362
1363 if (!new_element) {
1364 ret = -1;
1365 goto end;
1366 }
1367 CDS_INIT_LIST_HEAD(&new_element->node);
1368 new_element->trigger = trigger;
1369 cds_list_add(&new_element->node, &list->list);
1370end:
1371 return ret;
1372}
1373
1374static
1375bool trigger_applies_to_session(const struct lttng_trigger *trigger,
1376 const char *session_name)
1377{
1378 bool applies = false;
1379 const struct lttng_condition *condition;
1380
1381 condition = lttng_trigger_get_const_condition(trigger);
1382 switch (lttng_condition_get_type(condition)) {
1383 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
1384 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
1385 {
1386 enum lttng_condition_status condition_status;
1387 const char *condition_session_name;
1388
1389 condition_status = lttng_condition_session_rotation_get_session_name(
1390 condition, &condition_session_name);
1391 if (condition_status != LTTNG_CONDITION_STATUS_OK) {
1392 ERR("[notification-thread] Failed to retrieve session rotation condition's session name");
1393 goto end;
1394 }
1395
1396 assert(condition_session_name);
1397 applies = !strcmp(condition_session_name, session_name);
1398 break;
1399 }
1400 default:
1401 goto end;
1402 }
1403end:
1404 return applies;
1405}
1406
1407/*
1408 * Allocate and initialize an lttng_session_trigger_list which contains
1409 * all triggers that apply to the session named 'session_name'.
1410 *
1411 * No ownership of 'session_name' is assumed by the session trigger list.
1412 * It is the caller's responsability to ensure the session name is alive
1413 * for as long as this list is.
1414 */
1415static
1416struct lttng_session_trigger_list *lttng_session_trigger_list_build(
1417 const struct notification_thread_state *state,
1418 const char *session_name)
1419{
1420 int trigger_count = 0;
1421 struct lttng_session_trigger_list *session_trigger_list = NULL;
1422 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1423 struct cds_lfht_iter iter;
1424
1425 session_trigger_list = lttng_session_trigger_list_create(session_name,
1426 state->session_triggers_ht);
1427
1428 /* Add all triggers applying to the session named 'session_name'. */
1429 cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
1430 node) {
1431 int ret;
1432
1433 if (!trigger_applies_to_session(trigger_ht_element->trigger,
1434 session_name)) {
1435 continue;
1436 }
1437
1438 ret = lttng_session_trigger_list_add(session_trigger_list,
1439 trigger_ht_element->trigger);
1440 if (ret) {
1441 goto error;
1442 }
1443
1444 trigger_count++;
1445 }
1446
1447 DBG("[notification-thread] Found %i triggers that apply to newly created session",
1448 trigger_count);
1449 return session_trigger_list;
1450error:
1451 lttng_session_trigger_list_destroy(session_trigger_list);
1452 return NULL;
1453}
1454
8abe313a
JG
1455static
1456struct session_info *find_or_create_session_info(
1457 struct notification_thread_state *state,
1458 const char *name, uid_t uid, gid_t gid)
1459{
1460 struct session_info *session = NULL;
1461 struct cds_lfht_node *node;
1462 struct cds_lfht_iter iter;
ea9a44f0 1463 struct lttng_session_trigger_list *trigger_list;
8abe313a
JG
1464
1465 rcu_read_lock();
1466 cds_lfht_lookup(state->sessions_ht,
1467 hash_key_str(name, lttng_ht_seed),
1468 match_session,
1469 name,
1470 &iter);
1471 node = cds_lfht_iter_get_node(&iter);
1472 if (node) {
1473 DBG("[notification-thread] Found session info of session \"%s\" (uid = %i, gid = %i)",
1474 name, uid, gid);
1475 session = caa_container_of(node, struct session_info,
1476 sessions_ht_node);
1477 assert(session->uid == uid);
1478 assert(session->gid == gid);
1eee26c5
JG
1479 session_info_get(session);
1480 goto end;
ea9a44f0
JG
1481 }
1482
1483 trigger_list = lttng_session_trigger_list_build(state, name);
1484 if (!trigger_list) {
1485 goto error;
8abe313a
JG
1486 }
1487
1eee26c5
JG
1488 session = session_info_create(name, uid, gid, trigger_list,
1489 state->sessions_ht);
8abe313a
JG
1490 if (!session) {
1491 ERR("[notification-thread] Failed to allocation session info for session \"%s\" (uid = %i, gid = %i)",
1492 name, uid, gid);
ea9a44f0 1493 goto error;
8abe313a 1494 }
ea9a44f0 1495 trigger_list = NULL;
577983cb
JG
1496
1497 cds_lfht_add(state->sessions_ht, hash_key_str(name, lttng_ht_seed),
9b63a4aa 1498 &session->sessions_ht_node);
1eee26c5 1499end:
8abe313a
JG
1500 rcu_read_unlock();
1501 return session;
ea9a44f0
JG
1502error:
1503 rcu_read_unlock();
1504 session_info_put(session);
1505 return NULL;
8abe313a
JG
1506}
1507
ab0ee2ca
JG
1508static
1509int handle_notification_thread_command_add_channel(
8abe313a
JG
1510 struct notification_thread_state *state,
1511 const char *session_name, uid_t session_uid, gid_t session_gid,
1512 const char *channel_name, enum lttng_domain_type channel_domain,
1513 uint64_t channel_key_int, uint64_t channel_capacity,
1514 enum lttng_error_code *cmd_result)
ab0ee2ca
JG
1515{
1516 struct cds_list_head trigger_list;
8abe313a
JG
1517 struct channel_info *new_channel_info = NULL;
1518 struct channel_key channel_key = {
1519 .key = channel_key_int,
1520 .domain = channel_domain,
1521 };
ab0ee2ca
JG
1522 struct lttng_channel_trigger_list *channel_trigger_list = NULL;
1523 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1524 int trigger_count = 0;
1525 struct cds_lfht_iter iter;
8abe313a 1526 struct session_info *session_info = NULL;
ab0ee2ca
JG
1527
1528 DBG("[notification-thread] Adding channel %s from session %s, channel key = %" PRIu64 " in %s domain",
8abe313a
JG
1529 channel_name, session_name, channel_key_int,
1530 channel_domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
ab0ee2ca
JG
1531
1532 CDS_INIT_LIST_HEAD(&trigger_list);
1533
8abe313a
JG
1534 session_info = find_or_create_session_info(state, session_name,
1535 session_uid, session_gid);
1536 if (!session_info) {
a9577b76 1537 /* Allocation error or an internal error occurred. */
ab0ee2ca
JG
1538 goto error;
1539 }
1540
8abe313a
JG
1541 new_channel_info = channel_info_create(channel_name, &channel_key,
1542 channel_capacity, session_info);
1543 if (!new_channel_info) {
1544 goto error;
1545 }
ab0ee2ca
JG
1546
1547 /* Build a list of all triggers applying to the new channel. */
1548 cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
1549 node) {
1550 struct lttng_trigger_list_element *new_element;
1551
1552 if (!trigger_applies_to_channel(trigger_ht_element->trigger,
8abe313a 1553 new_channel_info)) {
ab0ee2ca
JG
1554 continue;
1555 }
1556
1557 new_element = zmalloc(sizeof(*new_element));
1558 if (!new_element) {
1559 goto error;
1560 }
1561 CDS_INIT_LIST_HEAD(&new_element->node);
1562 new_element->trigger = trigger_ht_element->trigger;
1563 cds_list_add(&new_element->node, &trigger_list);
1564 trigger_count++;
1565 }
1566
1567 DBG("[notification-thread] Found %i triggers that apply to newly added channel",
1568 trigger_count);
1569 channel_trigger_list = zmalloc(sizeof(*channel_trigger_list));
1570 if (!channel_trigger_list) {
1571 goto error;
1572 }
8abe313a 1573 channel_trigger_list->channel_key = new_channel_info->key;
ab0ee2ca
JG
1574 CDS_INIT_LIST_HEAD(&channel_trigger_list->list);
1575 cds_lfht_node_init(&channel_trigger_list->channel_triggers_ht_node);
1576 cds_list_splice(&trigger_list, &channel_trigger_list->list);
1577
1578 rcu_read_lock();
1579 /* Add channel to the channel_ht which owns the channel_infos. */
1580 cds_lfht_add(state->channels_ht,
8abe313a 1581 hash_channel_key(&new_channel_info->key),
ab0ee2ca
JG
1582 &new_channel_info->channels_ht_node);
1583 /*
1584 * Add the list of triggers associated with this channel to the
1585 * channel_triggers_ht.
1586 */
1587 cds_lfht_add(state->channel_triggers_ht,
8abe313a 1588 hash_channel_key(&new_channel_info->key),
ab0ee2ca
JG
1589 &channel_trigger_list->channel_triggers_ht_node);
1590 rcu_read_unlock();
1eee26c5 1591 session_info_put(session_info);
ab0ee2ca
JG
1592 *cmd_result = LTTNG_OK;
1593 return 0;
1594error:
ab0ee2ca 1595 channel_info_destroy(new_channel_info);
8abe313a 1596 session_info_put(session_info);
ab0ee2ca
JG
1597 return 1;
1598}
1599
1600static
1601int handle_notification_thread_command_remove_channel(
1602 struct notification_thread_state *state,
1603 uint64_t channel_key, enum lttng_domain_type domain,
1604 enum lttng_error_code *cmd_result)
1605{
1606 struct cds_lfht_node *node;
1607 struct cds_lfht_iter iter;
1608 struct lttng_channel_trigger_list *trigger_list;
1609 struct lttng_trigger_list_element *trigger_list_element, *tmp;
1610 struct channel_key key = { .key = channel_key, .domain = domain };
1611 struct channel_info *channel_info;
1612
1613 DBG("[notification-thread] Removing channel key = %" PRIu64 " in %s domain",
1614 channel_key, domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
1615
1616 rcu_read_lock();
1617
1618 cds_lfht_lookup(state->channel_triggers_ht,
1619 hash_channel_key(&key),
1620 match_channel_trigger_list,
1621 &key,
1622 &iter);
1623 node = cds_lfht_iter_get_node(&iter);
1624 /*
1625 * There is a severe internal error if we are being asked to remove a
1626 * channel that doesn't exist.
1627 */
1628 if (!node) {
1629 ERR("[notification-thread] Channel being removed is unknown to the notification thread");
1630 goto end;
1631 }
1632
1633 /* Free the list of triggers associated with this channel. */
1634 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
1635 channel_triggers_ht_node);
1636 cds_list_for_each_entry_safe(trigger_list_element, tmp,
1637 &trigger_list->list, node) {
1638 cds_list_del(&trigger_list_element->node);
1639 free(trigger_list_element);
1640 }
1641 cds_lfht_del(state->channel_triggers_ht, node);
1642 free(trigger_list);
1643
1644 /* Free sampled channel state. */
1645 cds_lfht_lookup(state->channel_state_ht,
1646 hash_channel_key(&key),
1647 match_channel_state_sample,
1648 &key,
1649 &iter);
1650 node = cds_lfht_iter_get_node(&iter);
1651 /*
1652 * This is expected to be NULL if the channel is destroyed before we
1653 * received a sample.
1654 */
1655 if (node) {
1656 struct channel_state_sample *sample = caa_container_of(node,
1657 struct channel_state_sample,
1658 channel_state_ht_node);
1659
1660 cds_lfht_del(state->channel_state_ht, node);
1661 free(sample);
1662 }
1663
1664 /* Remove the channel from the channels_ht and free it. */
1665 cds_lfht_lookup(state->channels_ht,
1666 hash_channel_key(&key),
1667 match_channel_info,
1668 &key,
1669 &iter);
1670 node = cds_lfht_iter_get_node(&iter);
1671 assert(node);
1672 channel_info = caa_container_of(node, struct channel_info,
1673 channels_ht_node);
1674 cds_lfht_del(state->channels_ht, node);
1675 channel_info_destroy(channel_info);
1676end:
1677 rcu_read_unlock();
1678 *cmd_result = LTTNG_OK;
1679 return 0;
1680}
1681
0ca52944 1682static
ed327204 1683int handle_notification_thread_command_session_rotation(
0ca52944 1684 struct notification_thread_state *state,
ed327204
JG
1685 enum notification_thread_command_type cmd_type,
1686 const char *session_name, uid_t session_uid, gid_t session_gid,
1687 uint64_t trace_archive_chunk_id,
1688 struct lttng_trace_archive_location *location,
1689 enum lttng_error_code *_cmd_result)
0ca52944 1690{
ed327204
JG
1691 int ret = 0;
1692 enum lttng_error_code cmd_result = LTTNG_OK;
1693 struct lttng_session_trigger_list *trigger_list;
1694 struct lttng_trigger_list_element *trigger_list_element;
1695 struct session_info *session_info;
0ca52944 1696
ed327204
JG
1697 rcu_read_lock();
1698
1699 session_info = find_or_create_session_info(state, session_name,
1700 session_uid, session_gid);
1701 if (!session_info) {
a9577b76 1702 /* Allocation error or an internal error occurred. */
ed327204
JG
1703 ret = -1;
1704 cmd_result = LTTNG_ERR_NOMEM;
1705 goto end;
1706 }
1707
1708 session_info->rotation.ongoing =
1709 cmd_type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING;
1710 session_info->rotation.id = trace_archive_chunk_id;
1711 trigger_list = get_session_trigger_list(state, session_name);
1712 if (!trigger_list) {
1713 DBG("[notification-thread] No triggers applying to session \"%s\" found",
1714 session_name);
1715 goto end;
1716 }
1717
1718 cds_list_for_each_entry(trigger_list_element, &trigger_list->list,
1719 node) {
1720 const struct lttng_condition *condition;
1721 const struct lttng_action *action;
1722 const struct lttng_trigger *trigger;
1723 struct notification_client_list *client_list;
1724 struct lttng_evaluation *evaluation = NULL;
1725 enum lttng_condition_type condition_type;
1726
1727 trigger = trigger_list_element->trigger;
1728 condition = lttng_trigger_get_const_condition(trigger);
1729 assert(condition);
1730 condition_type = lttng_condition_get_type(condition);
1731
1732 if (condition_type == LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING &&
1733 cmd_type != NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING) {
1734 continue;
1735 } else if (condition_type == LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED &&
1736 cmd_type != NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED) {
1737 continue;
1738 }
1739
1740 action = lttng_trigger_get_const_action(trigger);
1741
1742 /* Notify actions are the only type currently supported. */
1743 assert(lttng_action_get_type_const(action) ==
1744 LTTNG_ACTION_TYPE_NOTIFY);
1745
1746 client_list = get_client_list_from_condition(state, condition);
1747 assert(client_list);
1748
1749 if (cds_list_empty(&client_list->list)) {
1750 /*
1751 * No clients interested in the evaluation's result,
1752 * skip it.
1753 */
1754 continue;
1755 }
1756
1757 if (cmd_type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING) {
1758 evaluation = lttng_evaluation_session_rotation_ongoing_create(
1759 trace_archive_chunk_id);
1760 } else {
1761 evaluation = lttng_evaluation_session_rotation_completed_create(
1762 trace_archive_chunk_id, location);
1763 }
1764
1765 if (!evaluation) {
1766 /* Internal error */
1767 ret = -1;
1768 cmd_result = LTTNG_ERR_UNK;
1769 goto end;
1770 }
1771
1772 /* Dispatch evaluation result to all clients. */
1773 ret = send_evaluation_to_clients(trigger_list_element->trigger,
1774 evaluation, client_list, state,
1775 session_info->uid,
1776 session_info->gid);
1777 lttng_evaluation_destroy(evaluation);
1778 if (caa_unlikely(ret)) {
1779 goto end;
1780 }
1781 }
1782end:
1783 session_info_put(session_info);
1784 *_cmd_result = cmd_result;
1785 rcu_read_unlock();
1786 return ret;
0ca52944
JG
1787}
1788
1da26331
JG
1789static
1790int condition_is_supported(struct lttng_condition *condition)
1791{
1792 int ret;
1793
1794 switch (lttng_condition_get_type(condition)) {
1795 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
1796 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
1797 {
1798 enum lttng_domain_type domain;
1799
1800 ret = lttng_condition_buffer_usage_get_domain_type(condition,
1801 &domain);
1802 if (ret) {
1803 ret = -1;
1804 goto end;
1805 }
1806
1807 if (domain != LTTNG_DOMAIN_KERNEL) {
1808 ret = 1;
1809 goto end;
1810 }
1811
1812 /*
1813 * Older kernel tracers don't expose the API to monitor their
1814 * buffers. Therefore, we reject triggers that require that
1815 * mechanism to be available to be evaluated.
1816 */
1817 ret = kernel_supports_ring_buffer_snapshot_sample_positions(
1818 kernel_tracer_fd);
1819 break;
1820 }
1821 default:
1822 ret = 1;
1823 }
1824end:
1825 return ret;
1826}
1827
51eab943
JG
1828/* Must be called with RCU read lock held. */
1829static
1830int bind_trigger_to_matching_session(const struct lttng_trigger *trigger,
1831 struct notification_thread_state *state)
1832{
1833 int ret = 0;
51eab943
JG
1834 const struct lttng_condition *condition;
1835 const char *session_name;
1836 struct lttng_session_trigger_list *trigger_list;
1837
1838 condition = lttng_trigger_get_const_condition(trigger);
1839 switch (lttng_condition_get_type(condition)) {
1840 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
1841 case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
1842 {
1843 enum lttng_condition_status status;
1844
1845 status = lttng_condition_session_rotation_get_session_name(
1846 condition, &session_name);
1847 if (status != LTTNG_CONDITION_STATUS_OK) {
1848 ERR("[notification-thread] Failed to bind trigger to session: unable to get 'session_rotation' condition's session name");
1849 ret = -1;
1850 goto end;
1851 }
1852 break;
1853 }
1854 default:
1855 ret = -1;
1856 goto end;
1857 }
1858
ed327204
JG
1859 trigger_list = get_session_trigger_list(state, session_name);
1860 if (!trigger_list) {
51eab943
JG
1861 DBG("[notification-thread] Unable to bind trigger applying to session \"%s\" as it is not yet known to the notification system",
1862 session_name);
1863 goto end;
51eab943 1864
ed327204 1865 }
51eab943
JG
1866
1867 DBG("[notification-thread] Newly registered trigger bound to session \"%s\"",
1868 session_name);
1869 ret = lttng_session_trigger_list_add(trigger_list, trigger);
1870end:
1871 return ret;
1872}
1873
1874/* Must be called with RCU read lock held. */
1875static
1876int bind_trigger_to_matching_channels(const struct lttng_trigger *trigger,
1877 struct notification_thread_state *state)
1878{
1879 int ret = 0;
1880 struct cds_lfht_node *node;
1881 struct cds_lfht_iter iter;
1882 struct channel_info *channel;
1883
1884 cds_lfht_for_each_entry(state->channels_ht, &iter, channel,
1885 channels_ht_node) {
1886 struct lttng_trigger_list_element *trigger_list_element;
1887 struct lttng_channel_trigger_list *trigger_list;
1888
1889 if (!trigger_applies_to_channel(trigger, channel)) {
1890 continue;
1891 }
1892
1893 cds_lfht_lookup(state->channel_triggers_ht,
1894 hash_channel_key(&channel->key),
1895 match_channel_trigger_list,
1896 &channel->key,
1897 &iter);
1898 node = cds_lfht_iter_get_node(&iter);
1899 assert(node);
1900 trigger_list = caa_container_of(node,
1901 struct lttng_channel_trigger_list,
1902 channel_triggers_ht_node);
1903
1904 trigger_list_element = zmalloc(sizeof(*trigger_list_element));
1905 if (!trigger_list_element) {
1906 ret = -1;
1907 goto end;
1908 }
1909 CDS_INIT_LIST_HEAD(&trigger_list_element->node);
1910 trigger_list_element->trigger = trigger;
1911 cds_list_add(&trigger_list_element->node, &trigger_list->list);
1912 DBG("[notification-thread] Newly registered trigger bound to channel \"%s\"",
1913 channel->name);
1914 }
1915end:
1916 return ret;
1917}
1918
ab0ee2ca
JG
1919/*
1920 * FIXME A client's credentials are not checked when registering a trigger, nor
1921 * are they stored alongside with the trigger.
1922 *
1da26331 1923 * The effects of this are benign since:
ab0ee2ca 1924 * - The client will succeed in registering the trigger, as it is valid,
51eab943 1925 * - The trigger will, internally, be bound to the channel/session,
ab0ee2ca
JG
1926 * - The notifications will not be sent since the client's credentials
1927 * are checked against the channel at that moment.
1da26331
JG
1928 *
1929 * If this function returns a non-zero value, it means something is
50ca7858 1930 * fundamentally broken and the whole subsystem/thread will be torn down.
1da26331
JG
1931 *
1932 * If a non-fatal error occurs, just set the cmd_result to the appropriate
1933 * error code.
ab0ee2ca
JG
1934 */
1935static
1936int handle_notification_thread_command_register_trigger(
8abe313a
JG
1937 struct notification_thread_state *state,
1938 struct lttng_trigger *trigger,
1939 enum lttng_error_code *cmd_result)
ab0ee2ca
JG
1940{
1941 int ret = 0;
1942 struct lttng_condition *condition;
1943 struct notification_client *client;
1944 struct notification_client_list *client_list = NULL;
1945 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
1946 struct notification_client_list_element *client_list_element, *tmp;
1947 struct cds_lfht_node *node;
1948 struct cds_lfht_iter iter;
ab0ee2ca
JG
1949 bool free_trigger = true;
1950
1951 rcu_read_lock();
1952
1953 condition = lttng_trigger_get_condition(trigger);
1da26331
JG
1954 assert(condition);
1955
1956 ret = condition_is_supported(condition);
1957 if (ret < 0) {
1958 goto error;
1959 } else if (ret == 0) {
1960 *cmd_result = LTTNG_ERR_NOT_SUPPORTED;
1961 goto error;
1962 } else {
1963 /* Feature is supported, continue. */
1964 ret = 0;
1965 }
1966
ab0ee2ca
JG
1967 trigger_ht_element = zmalloc(sizeof(*trigger_ht_element));
1968 if (!trigger_ht_element) {
1969 ret = -1;
1970 goto error;
1971 }
1972
1973 /* Add trigger to the trigger_ht. */
1974 cds_lfht_node_init(&trigger_ht_element->node);
1975 trigger_ht_element->trigger = trigger;
1976
1977 node = cds_lfht_add_unique(state->triggers_ht,
1978 lttng_condition_hash(condition),
1979 match_condition,
1980 condition,
1981 &trigger_ht_element->node);
1982 if (node != &trigger_ht_element->node) {
1983 /* Not a fatal error, simply report it to the client. */
1984 *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
1985 goto error_free_ht_element;
1986 }
1987
1988 /*
1989 * Ownership of the trigger and of its wrapper was transfered to
1990 * the triggers_ht.
1991 */
1992 trigger_ht_element = NULL;
1993 free_trigger = false;
1994
1995 /*
1996 * The rest only applies to triggers that have a "notify" action.
1997 * It is not skipped as this is the only action type currently
1998 * supported.
1999 */
2000 client_list = zmalloc(sizeof(*client_list));
2001 if (!client_list) {
2002 ret = -1;
2003 goto error_free_ht_element;
2004 }
2005 cds_lfht_node_init(&client_list->notification_trigger_ht_node);
2006 CDS_INIT_LIST_HEAD(&client_list->list);
2007 client_list->trigger = trigger;
2008
2009 /* Build a list of clients to which this new trigger applies. */
2010 cds_lfht_for_each_entry(state->client_socket_ht, &iter, client,
2011 client_socket_ht_node) {
2012 if (!trigger_applies_to_client(trigger, client)) {
2013 continue;
2014 }
2015
2016 client_list_element = zmalloc(sizeof(*client_list_element));
2017 if (!client_list_element) {
2018 ret = -1;
2019 goto error_free_client_list;
2020 }
2021 CDS_INIT_LIST_HEAD(&client_list_element->node);
2022 client_list_element->client = client;
2023 cds_list_add(&client_list_element->node, &client_list->list);
2024 }
2025
2026 cds_lfht_add(state->notification_trigger_clients_ht,
2027 lttng_condition_hash(condition),
2028 &client_list->notification_trigger_ht_node);
ab0ee2ca 2029
f82f93a1 2030 switch (get_condition_binding_object(condition)) {
51eab943
JG
2031 case LTTNG_OBJECT_TYPE_SESSION:
2032 /* Add the trigger to the list if it matches a known session. */
2033 ret = bind_trigger_to_matching_session(trigger, state);
2034 if (ret) {
2035 goto error_free_client_list;
ab0ee2ca 2036 }
f82f93a1 2037 break;
51eab943
JG
2038 case LTTNG_OBJECT_TYPE_CHANNEL:
2039 /*
2040 * Add the trigger to list of triggers bound to the channels
2041 * currently known.
2042 */
2043 ret = bind_trigger_to_matching_channels(trigger, state);
2044 if (ret) {
ab0ee2ca
JG
2045 goto error_free_client_list;
2046 }
51eab943
JG
2047 break;
2048 case LTTNG_OBJECT_TYPE_NONE:
2049 break;
2050 default:
2051 ERR("[notification-thread] Unknown object type on which to bind a newly registered trigger was encountered");
2052 ret = -1;
2053 goto error_free_client_list;
ab0ee2ca
JG
2054 }
2055
2ae99f0b
JG
2056 /*
2057 * Since there is nothing preventing clients from subscribing to a
2058 * condition before the corresponding trigger is registered, we have
2059 * to evaluate this new condition right away.
2060 *
2061 * At some point, we were waiting for the next "evaluation" (e.g. on
2062 * reception of a channel sample) to evaluate this new condition, but
2063 * that was broken.
2064 *
2065 * The reason it was broken is that waiting for the next sample
2066 * does not allow us to properly handle transitions for edge-triggered
2067 * conditions.
2068 *
2069 * Consider this example: when we handle a new channel sample, we
2070 * evaluate each conditions twice: once with the previous state, and
2071 * again with the newest state. We then use those two results to
2072 * determine whether a state change happened: a condition was false and
2073 * became true. If a state change happened, we have to notify clients.
2074 *
2075 * Now, if a client subscribes to a given notification and registers
2076 * a trigger *after* that subscription, we have to make sure the
2077 * condition is evaluated at this point while considering only the
2078 * current state. Otherwise, the next evaluation cycle may only see
2079 * that the evaluations remain the same (true for samples n-1 and n) and
2080 * the client will never know that the condition has been met.
2081 */
2082 cds_list_for_each_entry_safe(client_list_element, tmp,
2083 &client_list->list, node) {
2084 ret = evaluate_condition_for_client(trigger, condition,
2085 client_list_element->client, state);
2086 if (ret) {
2087 goto error_free_client_list;
2088 }
2089 }
2090
2091 /*
2092 * Client list ownership transferred to the
2093 * notification_trigger_clients_ht.
2094 */
2095 client_list = NULL;
2096
ab0ee2ca
JG
2097 *cmd_result = LTTNG_OK;
2098error_free_client_list:
2099 if (client_list) {
2100 cds_list_for_each_entry_safe(client_list_element, tmp,
2101 &client_list->list, node) {
2102 free(client_list_element);
2103 }
2104 free(client_list);
2105 }
2106error_free_ht_element:
2107 free(trigger_ht_element);
2108error:
2109 if (free_trigger) {
2110 struct lttng_action *action = lttng_trigger_get_action(trigger);
2111
2112 lttng_condition_destroy(condition);
2113 lttng_action_destroy(action);
2114 lttng_trigger_destroy(trigger);
2115 }
2116 rcu_read_unlock();
2117 return ret;
2118}
2119
cc2295b5 2120static
ab0ee2ca
JG
2121int handle_notification_thread_command_unregister_trigger(
2122 struct notification_thread_state *state,
2123 struct lttng_trigger *trigger,
2124 enum lttng_error_code *_cmd_reply)
2125{
2126 struct cds_lfht_iter iter;
ed327204 2127 struct cds_lfht_node *triggers_ht_node;
ab0ee2ca
JG
2128 struct lttng_channel_trigger_list *trigger_list;
2129 struct notification_client_list *client_list;
2130 struct notification_client_list_element *client_list_element, *tmp;
2131 struct lttng_trigger_ht_element *trigger_ht_element = NULL;
2132 struct lttng_condition *condition = lttng_trigger_get_condition(
2133 trigger);
2134 struct lttng_action *action;
2135 enum lttng_error_code cmd_reply;
2136
2137 rcu_read_lock();
2138
2139 cds_lfht_lookup(state->triggers_ht,
2140 lttng_condition_hash(condition),
2141 match_condition,
2142 condition,
2143 &iter);
2144 triggers_ht_node = cds_lfht_iter_get_node(&iter);
2145 if (!triggers_ht_node) {
2146 cmd_reply = LTTNG_ERR_TRIGGER_NOT_FOUND;
2147 goto end;
2148 } else {
2149 cmd_reply = LTTNG_OK;
2150 }
2151
2152 /* Remove trigger from channel_triggers_ht. */
2153 cds_lfht_for_each_entry(state->channel_triggers_ht, &iter, trigger_list,
2154 channel_triggers_ht_node) {
2155 struct lttng_trigger_list_element *trigger_element, *tmp;
2156
2157 cds_list_for_each_entry_safe(trigger_element, tmp,
2158 &trigger_list->list, node) {
9b63a4aa
JG
2159 const struct lttng_condition *current_condition =
2160 lttng_trigger_get_const_condition(
ab0ee2ca
JG
2161 trigger_element->trigger);
2162
2163 assert(current_condition);
2164 if (!lttng_condition_is_equal(condition,
2165 current_condition)) {
2166 continue;
2167 }
2168
2169 DBG("[notification-thread] Removed trigger from channel_triggers_ht");
2170 cds_list_del(&trigger_element->node);
e4db5ace
JR
2171 /* A trigger can only appear once per channel */
2172 break;
ab0ee2ca
JG
2173 }
2174 }
2175
2176 /*
2177 * Remove and release the client list from
2178 * notification_trigger_clients_ht.
2179 */
ed327204
JG
2180 client_list = get_client_list_from_condition(state, condition);
2181 assert(client_list);
2182
ab0ee2ca
JG
2183 cds_list_for_each_entry_safe(client_list_element, tmp,
2184 &client_list->list, node) {
2185 free(client_list_element);
2186 }
ed327204
JG
2187 cds_lfht_del(state->notification_trigger_clients_ht,
2188 &client_list->notification_trigger_ht_node);
ab0ee2ca
JG
2189 free(client_list);
2190
2191 /* Remove trigger from triggers_ht. */
2192 trigger_ht_element = caa_container_of(triggers_ht_node,
2193 struct lttng_trigger_ht_element, node);
2194 cds_lfht_del(state->triggers_ht, triggers_ht_node);
2195
2196 condition = lttng_trigger_get_condition(trigger_ht_element->trigger);
2197 lttng_condition_destroy(condition);
2198 action = lttng_trigger_get_action(trigger_ht_element->trigger);
2199 lttng_action_destroy(action);
2200 lttng_trigger_destroy(trigger_ht_element->trigger);
2201 free(trigger_ht_element);
2202end:
2203 rcu_read_unlock();
2204 if (_cmd_reply) {
2205 *_cmd_reply = cmd_reply;
2206 }
2207 return 0;
2208}
2209
2210/* Returns 0 on success, 1 on exit requested, negative value on error. */
2211int handle_notification_thread_command(
2212 struct notification_thread_handle *handle,
2213 struct notification_thread_state *state)
2214{
2215 int ret;
2216 uint64_t counter;
2217 struct notification_thread_command *cmd;
2218
8abe313a
JG
2219 /* Read the event pipe to put it back into a quiescent state. */
2220 ret = read(lttng_pipe_get_readfd(handle->cmd_queue.event_pipe), &counter,
2221 sizeof(counter));
ab0ee2ca
JG
2222 if (ret == -1) {
2223 goto error;
2224 }
2225
2226 pthread_mutex_lock(&handle->cmd_queue.lock);
2227 cmd = cds_list_first_entry(&handle->cmd_queue.list,
2228 struct notification_thread_command, cmd_list_node);
2229 switch (cmd->type) {
2230 case NOTIFICATION_COMMAND_TYPE_REGISTER_TRIGGER:
2231 DBG("[notification-thread] Received register trigger command");
2232 ret = handle_notification_thread_command_register_trigger(
2233 state, cmd->parameters.trigger,
2234 &cmd->reply_code);
2235 break;
2236 case NOTIFICATION_COMMAND_TYPE_UNREGISTER_TRIGGER:
2237 DBG("[notification-thread] Received unregister trigger command");
2238 ret = handle_notification_thread_command_unregister_trigger(
2239 state, cmd->parameters.trigger,
2240 &cmd->reply_code);
2241 break;
2242 case NOTIFICATION_COMMAND_TYPE_ADD_CHANNEL:
2243 DBG("[notification-thread] Received add channel command");
2244 ret = handle_notification_thread_command_add_channel(
8abe313a
JG
2245 state,
2246 cmd->parameters.add_channel.session.name,
2247 cmd->parameters.add_channel.session.uid,
2248 cmd->parameters.add_channel.session.gid,
2249 cmd->parameters.add_channel.channel.name,
2250 cmd->parameters.add_channel.channel.domain,
2251 cmd->parameters.add_channel.channel.key,
2252 cmd->parameters.add_channel.channel.capacity,
ab0ee2ca
JG
2253 &cmd->reply_code);
2254 break;
2255 case NOTIFICATION_COMMAND_TYPE_REMOVE_CHANNEL:
2256 DBG("[notification-thread] Received remove channel command");
2257 ret = handle_notification_thread_command_remove_channel(
2258 state, cmd->parameters.remove_channel.key,
2259 cmd->parameters.remove_channel.domain,
2260 &cmd->reply_code);
2261 break;
0ca52944 2262 case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING:
0ca52944 2263 case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED:
ed327204
JG
2264 DBG("[notification-thread] Received session rotation %s command",
2265 cmd->type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING ?
2266 "ongoing" : "completed");
2267 ret = handle_notification_thread_command_session_rotation(
0ca52944 2268 state,
ed327204
JG
2269 cmd->type,
2270 cmd->parameters.session_rotation.session_name,
2271 cmd->parameters.session_rotation.uid,
2272 cmd->parameters.session_rotation.gid,
2273 cmd->parameters.session_rotation.trace_archive_chunk_id,
2274 cmd->parameters.session_rotation.location,
0ca52944
JG
2275 &cmd->reply_code);
2276 break;
ab0ee2ca
JG
2277 case NOTIFICATION_COMMAND_TYPE_QUIT:
2278 DBG("[notification-thread] Received quit command");
2279 cmd->reply_code = LTTNG_OK;
2280 ret = 1;
2281 goto end;
2282 default:
2283 ERR("[notification-thread] Unknown internal command received");
2284 goto error_unlock;
2285 }
2286
2287 if (ret) {
2288 goto error_unlock;
2289 }
2290end:
2291 cds_list_del(&cmd->cmd_list_node);
8ada111f 2292 lttng_waiter_wake_up(&cmd->reply_waiter);
ab0ee2ca
JG
2293 pthread_mutex_unlock(&handle->cmd_queue.lock);
2294 return ret;
2295error_unlock:
2296 /* Wake-up and return a fatal error to the calling thread. */
8ada111f 2297 lttng_waiter_wake_up(&cmd->reply_waiter);
ab0ee2ca
JG
2298 pthread_mutex_unlock(&handle->cmd_queue.lock);
2299 cmd->reply_code = LTTNG_ERR_FATAL;
2300error:
2301 /* Indicate a fatal error to the caller. */
2302 return -1;
2303}
2304
2305static
2306unsigned long hash_client_socket(int socket)
2307{
2308 return hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed);
2309}
2310
2311static
2312int socket_set_non_blocking(int socket)
2313{
2314 int ret, flags;
2315
2316 /* Set the pipe as non-blocking. */
2317 ret = fcntl(socket, F_GETFL, 0);
2318 if (ret == -1) {
2319 PERROR("fcntl get socket flags");
2320 goto end;
2321 }
2322 flags = ret;
2323
2324 ret = fcntl(socket, F_SETFL, flags | O_NONBLOCK);
2325 if (ret == -1) {
2326 PERROR("fcntl set O_NONBLOCK socket flag");
2327 goto end;
2328 }
2329 DBG("Client socket (fd = %i) set as non-blocking", socket);
2330end:
2331 return ret;
2332}
2333
2334static
14fa22f8 2335int client_reset_inbound_state(struct notification_client *client)
ab0ee2ca
JG
2336{
2337 int ret;
2338
2339 ret = lttng_dynamic_buffer_set_size(
2340 &client->communication.inbound.buffer, 0);
2341 assert(!ret);
2342
2343 client->communication.inbound.bytes_to_receive =
2344 sizeof(struct lttng_notification_channel_message);
2345 client->communication.inbound.msg_type =
2346 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN;
ab0ee2ca
JG
2347 LTTNG_SOCK_SET_UID_CRED(&client->communication.inbound.creds, -1);
2348 LTTNG_SOCK_SET_GID_CRED(&client->communication.inbound.creds, -1);
14fa22f8
JG
2349 ret = lttng_dynamic_buffer_set_size(
2350 &client->communication.inbound.buffer,
2351 client->communication.inbound.bytes_to_receive);
2352 return ret;
ab0ee2ca
JG
2353}
2354
2355int handle_notification_thread_client_connect(
2356 struct notification_thread_state *state)
2357{
2358 int ret;
2359 struct notification_client *client;
2360
2361 DBG("[notification-thread] Handling new notification channel client connection");
2362
2363 client = zmalloc(sizeof(*client));
2364 if (!client) {
2365 /* Fatal error. */
2366 ret = -1;
2367 goto error;
2368 }
2369 CDS_INIT_LIST_HEAD(&client->condition_list);
2370 lttng_dynamic_buffer_init(&client->communication.inbound.buffer);
2371 lttng_dynamic_buffer_init(&client->communication.outbound.buffer);
01ea340e 2372 client->communication.inbound.expect_creds = true;
14fa22f8
JG
2373 ret = client_reset_inbound_state(client);
2374 if (ret) {
2375 ERR("[notification-thread] Failed to reset client communication's inbound state");
2376 ret = 0;
2377 goto error;
2378 }
ab0ee2ca
JG
2379
2380 ret = lttcomm_accept_unix_sock(state->notification_channel_socket);
2381 if (ret < 0) {
2382 ERR("[notification-thread] Failed to accept new notification channel client connection");
2383 ret = 0;
2384 goto error;
2385 }
2386
2387 client->socket = ret;
2388
2389 ret = socket_set_non_blocking(client->socket);
2390 if (ret) {
2391 ERR("[notification-thread] Failed to set new notification channel client connection socket as non-blocking");
2392 goto error;
2393 }
2394
2395 ret = lttcomm_setsockopt_creds_unix_sock(client->socket);
2396 if (ret < 0) {
2397 ERR("[notification-thread] Failed to set socket options on new notification channel client socket");
2398 ret = 0;
2399 goto error;
2400 }
2401
2402 ret = lttng_poll_add(&state->events, client->socket,
2403 LPOLLIN | LPOLLERR |
2404 LPOLLHUP | LPOLLRDHUP);
2405 if (ret < 0) {
2406 ERR("[notification-thread] Failed to add notification channel client socket to poll set");
2407 ret = 0;
2408 goto error;
2409 }
2410 DBG("[notification-thread] Added new notification channel client socket (%i) to poll set",
2411 client->socket);
2412
ab0ee2ca
JG
2413 rcu_read_lock();
2414 cds_lfht_add(state->client_socket_ht,
2415 hash_client_socket(client->socket),
2416 &client->client_socket_ht_node);
2417 rcu_read_unlock();
2418
2419 return ret;
2420error:
2421 notification_client_destroy(client, state);
2422 return ret;
2423}
2424
2425int handle_notification_thread_client_disconnect(
2426 int client_socket,
2427 struct notification_thread_state *state)
2428{
2429 int ret = 0;
2430 struct notification_client *client;
2431
2432 rcu_read_lock();
2433 DBG("[notification-thread] Closing client connection (socket fd = %i)",
2434 client_socket);
2435 client = get_client_from_socket(client_socket, state);
2436 if (!client) {
2437 /* Internal state corruption, fatal error. */
2438 ERR("[notification-thread] Unable to find client (socket fd = %i)",
2439 client_socket);
2440 ret = -1;
2441 goto end;
2442 }
2443
2444 ret = lttng_poll_del(&state->events, client_socket);
2445 if (ret) {
2446 ERR("[notification-thread] Failed to remove client socket from poll set");
2447 }
2448 cds_lfht_del(state->client_socket_ht,
2449 &client->client_socket_ht_node);
2450 notification_client_destroy(client, state);
2451end:
2452 rcu_read_unlock();
2453 return ret;
2454}
2455
2456int handle_notification_thread_client_disconnect_all(
2457 struct notification_thread_state *state)
2458{
2459 struct cds_lfht_iter iter;
2460 struct notification_client *client;
2461 bool error_encoutered = false;
2462
2463 rcu_read_lock();
2464 DBG("[notification-thread] Closing all client connections");
2465 cds_lfht_for_each_entry(state->client_socket_ht, &iter, client,
2466 client_socket_ht_node) {
2467 int ret;
2468
2469 ret = handle_notification_thread_client_disconnect(
2470 client->socket, state);
2471 if (ret) {
2472 error_encoutered = true;
2473 }
2474 }
2475 rcu_read_unlock();
2476 return error_encoutered ? 1 : 0;
2477}
2478
2479int handle_notification_thread_trigger_unregister_all(
2480 struct notification_thread_state *state)
2481{
4149ace8 2482 bool error_occurred = false;
ab0ee2ca
JG
2483 struct cds_lfht_iter iter;
2484 struct lttng_trigger_ht_element *trigger_ht_element;
2485
2486 cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
2487 node) {
2488 int ret = handle_notification_thread_command_unregister_trigger(
2489 state, trigger_ht_element->trigger, NULL);
2490 if (ret) {
4149ace8 2491 error_occurred = true;
ab0ee2ca
JG
2492 }
2493 }
4149ace8 2494 return error_occurred ? -1 : 0;
ab0ee2ca
JG
2495}
2496
2497static
2498int client_flush_outgoing_queue(struct notification_client *client,
2499 struct notification_thread_state *state)
2500{
2501 ssize_t ret;
2502 size_t to_send_count;
2503
2504 assert(client->communication.outbound.buffer.size != 0);
2505 to_send_count = client->communication.outbound.buffer.size;
2506 DBG("[notification-thread] Flushing client (socket fd = %i) outgoing queue",
2507 client->socket);
2508
2509 ret = lttcomm_send_unix_sock_non_block(client->socket,
2510 client->communication.outbound.buffer.data,
2511 to_send_count);
2512 if ((ret < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) ||
2513 (ret > 0 && ret < to_send_count)) {
2514 DBG("[notification-thread] Client (socket fd = %i) outgoing queue could not be completely flushed",
2515 client->socket);
2516 to_send_count -= max(ret, 0);
2517
2518 memcpy(client->communication.outbound.buffer.data,
2519 client->communication.outbound.buffer.data +
2520 client->communication.outbound.buffer.size - to_send_count,
2521 to_send_count);
2522 ret = lttng_dynamic_buffer_set_size(
2523 &client->communication.outbound.buffer,
2524 to_send_count);
2525 if (ret) {
2526 goto error;
2527 }
2528
2529 /*
2530 * We want to be notified whenever there is buffer space
2531 * available to send the rest of the payload.
2532 */
2533 ret = lttng_poll_mod(&state->events, client->socket,
2534 CLIENT_POLL_MASK_IN_OUT);
2535 if (ret) {
2536 goto error;
2537 }
2538 } else if (ret < 0) {
2539 /* Generic error, disconnect the client. */
2540 ERR("[notification-thread] Failed to send flush outgoing queue, disconnecting client (socket fd = %i)",
2541 client->socket);
2542 ret = handle_notification_thread_client_disconnect(
2543 client->socket, state);
2544 if (ret) {
2545 goto error;
2546 }
2547 } else {
2548 /* No error and flushed the queue completely. */
2549 ret = lttng_dynamic_buffer_set_size(
2550 &client->communication.outbound.buffer, 0);
2551 if (ret) {
2552 goto error;
2553 }
2554 ret = lttng_poll_mod(&state->events, client->socket,
2555 CLIENT_POLL_MASK_IN);
2556 if (ret) {
2557 goto error;
2558 }
2559
2560 client->communication.outbound.queued_command_reply = false;
2561 client->communication.outbound.dropped_notification = false;
2562 }
2563
2564 return 0;
2565error:
2566 return -1;
2567}
2568
2569static
2570int client_send_command_reply(struct notification_client *client,
2571 struct notification_thread_state *state,
2572 enum lttng_notification_channel_status status)
2573{
2574 int ret;
2575 struct lttng_notification_channel_command_reply reply = {
2576 .status = (int8_t) status,
2577 };
2578 struct lttng_notification_channel_message msg = {
2579 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY,
2580 .size = sizeof(reply),
2581 };
2582 char buffer[sizeof(msg) + sizeof(reply)];
2583
2584 if (client->communication.outbound.queued_command_reply) {
2585 /* Protocol error. */
2586 goto error;
2587 }
2588
2589 memcpy(buffer, &msg, sizeof(msg));
2590 memcpy(buffer + sizeof(msg), &reply, sizeof(reply));
2591 DBG("[notification-thread] Send command reply (%i)", (int) status);
2592
2593 /* Enqueue buffer to outgoing queue and flush it. */
2594 ret = lttng_dynamic_buffer_append(
2595 &client->communication.outbound.buffer,
2596 buffer, sizeof(buffer));
2597 if (ret) {
2598 goto error;
2599 }
2600
2601 ret = client_flush_outgoing_queue(client, state);
2602 if (ret) {
2603 goto error;
2604 }
2605
2606 if (client->communication.outbound.buffer.size != 0) {
2607 /* Queue could not be emptied. */
2608 client->communication.outbound.queued_command_reply = true;
2609 }
2610
2611 return 0;
2612error:
2613 return -1;
2614}
2615
2616static
2617int client_dispatch_message(struct notification_client *client,
2618 struct notification_thread_state *state)
2619{
2620 int ret = 0;
2621
2622 if (client->communication.inbound.msg_type !=
2623 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE &&
2624 client->communication.inbound.msg_type !=
2625 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN &&
2626 !client->validated) {
2627 WARN("[notification-thread] client attempted a command before handshake");
2628 ret = -1;
2629 goto end;
2630 }
2631
2632 switch (client->communication.inbound.msg_type) {
2633 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN:
2634 {
2635 /*
2636 * Receiving message header. The function will be called again
2637 * once the rest of the message as been received and can be
2638 * interpreted.
2639 */
2640 const struct lttng_notification_channel_message *msg;
2641
2642 assert(sizeof(*msg) ==
2643 client->communication.inbound.buffer.size);
2644 msg = (const struct lttng_notification_channel_message *)
2645 client->communication.inbound.buffer.data;
2646
2647 if (msg->size == 0 || msg->size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) {
2648 ERR("[notification-thread] Invalid notification channel message: length = %u", msg->size);
2649 ret = -1;
2650 goto end;
2651 }
2652
2653 switch (msg->type) {
2654 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE:
2655 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE:
2656 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE:
2657 break;
2658 default:
2659 ret = -1;
2660 ERR("[notification-thread] Invalid notification channel message: unexpected message type");
2661 goto end;
2662 }
2663
2664 client->communication.inbound.bytes_to_receive = msg->size;
2665 client->communication.inbound.msg_type =
2666 (enum lttng_notification_channel_message_type) msg->type;
ab0ee2ca 2667 ret = lttng_dynamic_buffer_set_size(
14fa22f8 2668 &client->communication.inbound.buffer, msg->size);
ab0ee2ca
JG
2669 if (ret) {
2670 goto end;
2671 }
2672 break;
2673 }
2674 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE:
2675 {
2676 struct lttng_notification_channel_command_handshake *handshake_client;
2677 struct lttng_notification_channel_command_handshake handshake_reply = {
2678 .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR,
2679 .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR,
2680 };
2681 struct lttng_notification_channel_message msg_header = {
2682 .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE,
2683 .size = sizeof(handshake_reply),
2684 };
2685 enum lttng_notification_channel_status status =
2686 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
2687 char send_buffer[sizeof(msg_header) + sizeof(handshake_reply)];
2688
2689 memcpy(send_buffer, &msg_header, sizeof(msg_header));
2690 memcpy(send_buffer + sizeof(msg_header), &handshake_reply,
2691 sizeof(handshake_reply));
2692
2693 handshake_client =
2694 (struct lttng_notification_channel_command_handshake *)
2695 client->communication.inbound.buffer.data;
47a32869 2696 client->major = handshake_client->major;
ab0ee2ca
JG
2697 client->minor = handshake_client->minor;
2698 if (!client->communication.inbound.creds_received) {
2699 ERR("[notification-thread] No credentials received from client");
2700 ret = -1;
2701 goto end;
2702 }
2703
2704 client->uid = LTTNG_SOCK_GET_UID_CRED(
2705 &client->communication.inbound.creds);
2706 client->gid = LTTNG_SOCK_GET_GID_CRED(
2707 &client->communication.inbound.creds);
2708 DBG("[notification-thread] Received handshake from client (uid = %u, gid = %u) with version %i.%i",
2709 client->uid, client->gid, (int) client->major,
2710 (int) client->minor);
2711
2712 if (handshake_client->major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) {
2713 status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNSUPPORTED_VERSION;
2714 }
2715
2716 ret = lttng_dynamic_buffer_append(&client->communication.outbound.buffer,
2717 send_buffer, sizeof(send_buffer));
2718 if (ret) {
2719 ERR("[notification-thread] Failed to send protocol version to notification channel client");
2720 goto end;
2721 }
2722
2723 ret = client_flush_outgoing_queue(client, state);
2724 if (ret) {
2725 goto end;
2726 }
2727
2728 ret = client_send_command_reply(client, state, status);
2729 if (ret) {
2730 ERR("[notification-thread] Failed to send reply to notification channel client");
2731 goto end;
2732 }
2733
2734 /* Set reception state to receive the next message header. */
14fa22f8
JG
2735 ret = client_reset_inbound_state(client);
2736 if (ret) {
2737 ERR("[notification-thread] Failed to reset client communication's inbound state");
2738 goto end;
2739 }
ab0ee2ca
JG
2740 client->validated = true;
2741 break;
2742 }
2743 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE:
2744 case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE:
2745 {
2746 struct lttng_condition *condition;
2747 enum lttng_notification_channel_status status =
2748 LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
2749 const struct lttng_buffer_view condition_view =
2750 lttng_buffer_view_from_dynamic_buffer(
2751 &client->communication.inbound.buffer,
2752 0, -1);
2753 size_t expected_condition_size =
2754 client->communication.inbound.buffer.size;
2755
2756 ret = lttng_condition_create_from_buffer(&condition_view,
2757 &condition);
2758 if (ret != expected_condition_size) {
2759 ERR("[notification-thread] Malformed condition received from client");
2760 goto end;
2761 }
2762
2763 if (client->communication.inbound.msg_type ==
2764 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE) {
ab0ee2ca
JG
2765 ret = notification_thread_client_subscribe(client,
2766 condition, state, &status);
2767 } else {
2768 ret = notification_thread_client_unsubscribe(client,
2769 condition, state, &status);
2770 }
2771 if (ret) {
2772 goto end;
2773 }
2774
2775 ret = client_send_command_reply(client, state, status);
2776 if (ret) {
2777 ERR("[notification-thread] Failed to send reply to notification channel client");
2778 goto end;
2779 }
2780
2781 /* Set reception state to receive the next message header. */
14fa22f8
JG
2782 ret = client_reset_inbound_state(client);
2783 if (ret) {
2784 ERR("[notification-thread] Failed to reset client communication's inbound state");
2785 goto end;
2786 }
ab0ee2ca
JG
2787 break;
2788 }
2789 default:
2790 abort();
2791 }
2792end:
2793 return ret;
2794}
2795
2796/* Incoming data from client. */
2797int handle_notification_thread_client_in(
2798 struct notification_thread_state *state, int socket)
2799{
14fa22f8 2800 int ret = 0;
ab0ee2ca
JG
2801 struct notification_client *client;
2802 ssize_t recv_ret;
2803 size_t offset;
2804
2805 client = get_client_from_socket(socket, state);
2806 if (!client) {
2807 /* Internal error, abort. */
2808 ret = -1;
2809 goto end;
2810 }
2811
14fa22f8
JG
2812 offset = client->communication.inbound.buffer.size -
2813 client->communication.inbound.bytes_to_receive;
01ea340e 2814 if (client->communication.inbound.expect_creds) {
ab0ee2ca
JG
2815 recv_ret = lttcomm_recv_creds_unix_sock(socket,
2816 client->communication.inbound.buffer.data + offset,
2817 client->communication.inbound.bytes_to_receive,
2818 &client->communication.inbound.creds);
2819 if (recv_ret > 0) {
01ea340e 2820 client->communication.inbound.expect_creds = false;
ab0ee2ca
JG
2821 client->communication.inbound.creds_received = true;
2822 }
2823 } else {
2824 recv_ret = lttcomm_recv_unix_sock_non_block(socket,
2825 client->communication.inbound.buffer.data + offset,
2826 client->communication.inbound.bytes_to_receive);
2827 }
2828 if (recv_ret < 0) {
2829 goto error_disconnect_client;
2830 }
2831
2832 client->communication.inbound.bytes_to_receive -= recv_ret;
ab0ee2ca
JG
2833 if (client->communication.inbound.bytes_to_receive == 0) {
2834 ret = client_dispatch_message(client, state);
2835 if (ret) {
2836 /*
2837 * Only returns an error if this client must be
2838 * disconnected.
2839 */
2840 goto error_disconnect_client;
2841 }
2842 } else {
2843 goto end;
2844 }
2845end:
2846 return ret;
2847error_disconnect_client:
2848 ret = handle_notification_thread_client_disconnect(socket, state);
2849 return ret;
2850}
2851
2852/* Client ready to receive outgoing data. */
2853int handle_notification_thread_client_out(
2854 struct notification_thread_state *state, int socket)
2855{
2856 int ret;
2857 struct notification_client *client;
2858
2859 client = get_client_from_socket(socket, state);
2860 if (!client) {
2861 /* Internal error, abort. */
2862 ret = -1;
2863 goto end;
2864 }
2865
2866 ret = client_flush_outgoing_queue(client, state);
2867 if (ret) {
2868 goto end;
2869 }
2870end:
2871 return ret;
2872}
2873
2874static
e8360425
JD
2875bool evaluate_buffer_usage_condition(const struct lttng_condition *condition,
2876 const struct channel_state_sample *sample,
2877 uint64_t buffer_capacity)
ab0ee2ca
JG
2878{
2879 bool result = false;
2880 uint64_t threshold;
2881 enum lttng_condition_type condition_type;
e8360425 2882 const struct lttng_condition_buffer_usage *use_condition = container_of(
ab0ee2ca
JG
2883 condition, struct lttng_condition_buffer_usage,
2884 parent);
2885
ab0ee2ca
JG
2886 if (use_condition->threshold_bytes.set) {
2887 threshold = use_condition->threshold_bytes.value;
2888 } else {
2889 /*
2890 * Threshold was expressed as a ratio.
2891 *
2892 * TODO the threshold (in bytes) of conditions expressed
2893 * as a ratio of total buffer size could be cached to
2894 * forego this double-multiplication or it could be performed
2895 * as fixed-point math.
2896 *
2897 * Note that caching should accomodate the case where the
2898 * condition applies to multiple channels (i.e. don't assume
2899 * that all channels matching my_chann* have the same size...)
2900 */
2901 threshold = (uint64_t) (use_condition->threshold_ratio.value *
2902 (double) buffer_capacity);
2903 }
2904
2905 condition_type = lttng_condition_get_type(condition);
2906 if (condition_type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW) {
2907 DBG("[notification-thread] Low buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
2908 threshold, sample->highest_usage);
2909
2910 /*
2911 * The low condition should only be triggered once _all_ of the
2912 * streams in a channel have gone below the "low" threshold.
2913 */
2914 if (sample->highest_usage <= threshold) {
2915 result = true;
2916 }
2917 } else {
2918 DBG("[notification-thread] High buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
2919 threshold, sample->highest_usage);
2920
2921 /*
2922 * For high buffer usage scenarios, we want to trigger whenever
2923 * _any_ of the streams has reached the "high" threshold.
2924 */
2925 if (sample->highest_usage >= threshold) {
2926 result = true;
2927 }
2928 }
e8360425 2929
ab0ee2ca
JG
2930 return result;
2931}
2932
2933static
e8360425
JD
2934bool evaluate_session_consumed_size_condition(
2935 const struct lttng_condition *condition,
2936 uint64_t session_consumed_size)
2937{
2938 uint64_t threshold;
2939 const struct lttng_condition_session_consumed_size *size_condition =
2940 container_of(condition,
2941 struct lttng_condition_session_consumed_size,
2942 parent);
2943
2944 threshold = size_condition->consumed_threshold_bytes.value;
2945 DBG("[notification-thread] Session consumed size condition being evaluated: threshold = %" PRIu64 ", current size = %" PRIu64,
2946 threshold, session_consumed_size);
2947 return session_consumed_size >= threshold;
2948}
2949
2950static
ed327204 2951int evaluate_buffer_condition(const struct lttng_condition *condition,
ab0ee2ca 2952 struct lttng_evaluation **evaluation,
e8360425
JD
2953 const struct notification_thread_state *state,
2954 const struct channel_state_sample *previous_sample,
2955 const struct channel_state_sample *latest_sample,
2956 uint64_t previous_session_consumed_total,
2957 uint64_t latest_session_consumed_total,
2958 struct channel_info *channel_info)
ab0ee2ca
JG
2959{
2960 int ret = 0;
2961 enum lttng_condition_type condition_type;
e8360425
JD
2962 const bool previous_sample_available = !!previous_sample;
2963 bool previous_sample_result = false;
ab0ee2ca
JG
2964 bool latest_sample_result;
2965
2966 condition_type = lttng_condition_get_type(condition);
ab0ee2ca 2967
e8360425
JD
2968 switch (condition_type) {
2969 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
2970 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
2971 if (caa_likely(previous_sample_available)) {
2972 previous_sample_result =
2973 evaluate_buffer_usage_condition(condition,
2974 previous_sample, channel_info->capacity);
2975 }
2976 latest_sample_result = evaluate_buffer_usage_condition(
2977 condition, latest_sample,
2978 channel_info->capacity);
2979 break;
2980 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
2981 if (caa_likely(previous_sample_available)) {
2982 previous_sample_result =
2983 evaluate_session_consumed_size_condition(
2984 condition,
2985 previous_session_consumed_total);
2986 }
2987 latest_sample_result =
2988 evaluate_session_consumed_size_condition(
2989 condition,
2990 latest_session_consumed_total);
2991 break;
2992 default:
2993 /* Unknown condition type; internal error. */
2994 abort();
2995 }
ab0ee2ca
JG
2996
2997 if (!latest_sample_result ||
2998 (previous_sample_result == latest_sample_result)) {
2999 /*
3000 * Only trigger on a condition evaluation transition.
3001 *
3002 * NOTE: This edge-triggered logic may not be appropriate for
3003 * future condition types.
3004 */
3005 goto end;
3006 }
3007
e8360425
JD
3008 if (!evaluation || !latest_sample_result) {
3009 goto end;
3010 }
3011
3012 switch (condition_type) {
3013 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
3014 case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
ab0ee2ca
JG
3015 *evaluation = lttng_evaluation_buffer_usage_create(
3016 condition_type,
3017 latest_sample->highest_usage,
e8360425
JD
3018 channel_info->capacity);
3019 break;
3020 case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
3021 *evaluation = lttng_evaluation_session_consumed_size_create(
e8360425
JD
3022 latest_session_consumed_total);
3023 break;
3024 default:
3025 abort();
3026 }
3027
3028 if (!*evaluation) {
3029 ret = -1;
3030 goto end;
ab0ee2ca
JG
3031 }
3032end:
3033 return ret;
3034}
3035
3036static
3037int client_enqueue_dropped_notification(struct notification_client *client,
3038 struct notification_thread_state *state)
3039{
3040 int ret;
3041 struct lttng_notification_channel_message msg = {
3042 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED,
3043 .size = 0,
3044 };
3045
3046 ret = lttng_dynamic_buffer_append(
3047 &client->communication.outbound.buffer, &msg,
3048 sizeof(msg));
3049 return ret;
3050}
3051
3052static
9b63a4aa
JG
3053int send_evaluation_to_clients(const struct lttng_trigger *trigger,
3054 const struct lttng_evaluation *evaluation,
ab0ee2ca
JG
3055 struct notification_client_list* client_list,
3056 struct notification_thread_state *state,
3057 uid_t channel_uid, gid_t channel_gid)
3058{
3059 int ret = 0;
3060 struct lttng_dynamic_buffer msg_buffer;
3061 struct notification_client_list_element *client_list_element, *tmp;
9b63a4aa
JG
3062 const struct lttng_notification notification = {
3063 .condition = (struct lttng_condition *) lttng_trigger_get_const_condition(trigger),
3064 .evaluation = (struct lttng_evaluation *) evaluation,
3065 };
3647288f
JG
3066 struct lttng_notification_channel_message msg_header = {
3067 .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION,
3068 };
ab0ee2ca
JG
3069
3070 lttng_dynamic_buffer_init(&msg_buffer);
3071
3647288f
JG
3072 ret = lttng_dynamic_buffer_append(&msg_buffer, &msg_header,
3073 sizeof(msg_header));
ab0ee2ca
JG
3074 if (ret) {
3075 goto end;
3076 }
3077
9b63a4aa 3078 ret = lttng_notification_serialize(&notification, &msg_buffer);
ab0ee2ca 3079 if (ret) {
ab0ee2ca
JG
3080 ERR("[notification-thread] Failed to serialize notification");
3081 ret = -1;
3082 goto end;
3083 }
3084
3647288f
JG
3085 /* Update payload size. */
3086 ((struct lttng_notification_channel_message * ) msg_buffer.data)->size =
3087 (uint32_t) (msg_buffer.size - sizeof(msg_header));
3088
ab0ee2ca
JG
3089 cds_list_for_each_entry_safe(client_list_element, tmp,
3090 &client_list->list, node) {
3091 struct notification_client *client =
3092 client_list_element->client;
3093
3094 if (client->uid != channel_uid && client->gid != channel_gid &&
3095 client->uid != 0) {
3096 /* Client is not allowed to monitor this channel. */
3097 DBG("[notification-thread] Skipping client at it does not have the permission to receive notification for this channel");
3098 continue;
3099 }
3100
3101 DBG("[notification-thread] Sending notification to client (fd = %i, %zu bytes)",
3102 client->socket, msg_buffer.size);
3103 if (client->communication.outbound.buffer.size) {
3104 /*
3105 * Outgoing data is already buffered for this client;
3106 * drop the notification and enqueue a "dropped
3107 * notification" message if this is the first dropped
3108 * notification since the socket spilled-over to the
3109 * queue.
3110 */
3111 DBG("[notification-thread] Dropping notification addressed to client (socket fd = %i)",
3112 client->socket);
3113 if (!client->communication.outbound.dropped_notification) {
3114 client->communication.outbound.dropped_notification = true;
3115 ret = client_enqueue_dropped_notification(
3116 client, state);
3117 if (ret) {
3118 goto end;
3119 }
3120 }
3121 continue;
3122 }
3123
3124 ret = lttng_dynamic_buffer_append_buffer(
3125 &client->communication.outbound.buffer,
3126 &msg_buffer);
3127 if (ret) {
3128 goto end;
3129 }
3130
3131 ret = client_flush_outgoing_queue(client, state);
3132 if (ret) {
3133 goto end;
3134 }
3135 }
3136 ret = 0;
3137end:
ab0ee2ca
JG
3138 lttng_dynamic_buffer_reset(&msg_buffer);
3139 return ret;
3140}
3141
3142int handle_notification_thread_channel_sample(
3143 struct notification_thread_state *state, int pipe,
3144 enum lttng_domain_type domain)
3145{
3146 int ret = 0;
3147 struct lttcomm_consumer_channel_monitor_msg sample_msg;
ab0ee2ca
JG
3148 struct channel_info *channel_info;
3149 struct cds_lfht_node *node;
3150 struct cds_lfht_iter iter;
3151 struct lttng_channel_trigger_list *trigger_list;
3152 struct lttng_trigger_list_element *trigger_list_element;
3153 bool previous_sample_available = false;
e8360425
JD
3154 struct channel_state_sample previous_sample, latest_sample;
3155 uint64_t previous_session_consumed_total, latest_session_consumed_total;
ab0ee2ca
JG
3156
3157 /*
3158 * The monitoring pipe only holds messages smaller than PIPE_BUF,
3159 * ensuring that read/write of sampling messages are atomic.
3160 */
7c2551ef 3161 ret = lttng_read(pipe, &sample_msg, sizeof(sample_msg));
ab0ee2ca
JG
3162 if (ret != sizeof(sample_msg)) {
3163 ERR("[notification-thread] Failed to read from monitoring pipe (fd = %i)",
3164 pipe);
3165 ret = -1;
3166 goto end;
3167 }
3168
3169 ret = 0;
3170 latest_sample.key.key = sample_msg.key;
3171 latest_sample.key.domain = domain;
3172 latest_sample.highest_usage = sample_msg.highest;
3173 latest_sample.lowest_usage = sample_msg.lowest;
e8360425 3174 latest_sample.channel_total_consumed = sample_msg.total_consumed;
ab0ee2ca
JG
3175
3176 rcu_read_lock();
3177
3178 /* Retrieve the channel's informations */
3179 cds_lfht_lookup(state->channels_ht,
3180 hash_channel_key(&latest_sample.key),
3181 match_channel_info,
3182 &latest_sample.key,
3183 &iter);
3184 node = cds_lfht_iter_get_node(&iter);
e0b5f87b 3185 if (caa_unlikely(!node)) {
ab0ee2ca
JG
3186 /*
3187 * Not an error since the consumer can push a sample to the pipe
3188 * and the rest of the session daemon could notify us of the
3189 * channel's destruction before we get a chance to process that
3190 * sample.
3191 */
3192 DBG("[notification-thread] Received a sample for an unknown channel from consumerd, key = %" PRIu64 " in %s domain",
3193 latest_sample.key.key,
3194 domain == LTTNG_DOMAIN_KERNEL ? "kernel" :
3195 "user space");
3196 goto end_unlock;
3197 }
3198 channel_info = caa_container_of(node, struct channel_info,
3199 channels_ht_node);
e8360425 3200 DBG("[notification-thread] Handling channel sample for channel %s (key = %" PRIu64 ") in session %s (highest usage = %" PRIu64 ", lowest usage = %" PRIu64", total consumed = %" PRIu64")",
8abe313a 3201 channel_info->name,
ab0ee2ca 3202 latest_sample.key.key,
8abe313a 3203 channel_info->session_info->name,
ab0ee2ca 3204 latest_sample.highest_usage,
e8360425
JD
3205 latest_sample.lowest_usage,
3206 latest_sample.channel_total_consumed);
3207
3208 previous_session_consumed_total =
3209 channel_info->session_info->consumed_data_size;
ab0ee2ca
JG
3210
3211 /* Retrieve the channel's last sample, if it exists, and update it. */
3212 cds_lfht_lookup(state->channel_state_ht,
3213 hash_channel_key(&latest_sample.key),
3214 match_channel_state_sample,
3215 &latest_sample.key,
3216 &iter);
3217 node = cds_lfht_iter_get_node(&iter);
e0b5f87b 3218 if (caa_likely(node)) {
ab0ee2ca
JG
3219 struct channel_state_sample *stored_sample;
3220
3221 /* Update the sample stored. */
3222 stored_sample = caa_container_of(node,
3223 struct channel_state_sample,
3224 channel_state_ht_node);
e8360425 3225
ab0ee2ca
JG
3226 memcpy(&previous_sample, stored_sample,
3227 sizeof(previous_sample));
3228 stored_sample->highest_usage = latest_sample.highest_usage;
3229 stored_sample->lowest_usage = latest_sample.lowest_usage;
0f0479d7 3230 stored_sample->channel_total_consumed = latest_sample.channel_total_consumed;
ab0ee2ca 3231 previous_sample_available = true;
e8360425
JD
3232
3233 latest_session_consumed_total =
3234 previous_session_consumed_total +
3235 (latest_sample.channel_total_consumed - previous_sample.channel_total_consumed);
ab0ee2ca
JG
3236 } else {
3237 /*
3238 * This is the channel's first sample, allocate space for and
3239 * store the new sample.
3240 */
3241 struct channel_state_sample *stored_sample;
3242
3243 stored_sample = zmalloc(sizeof(*stored_sample));
3244 if (!stored_sample) {
3245 ret = -1;
3246 goto end_unlock;
3247 }
3248
3249 memcpy(stored_sample, &latest_sample, sizeof(*stored_sample));
3250 cds_lfht_node_init(&stored_sample->channel_state_ht_node);
3251 cds_lfht_add(state->channel_state_ht,
3252 hash_channel_key(&stored_sample->key),
3253 &stored_sample->channel_state_ht_node);
e8360425
JD
3254
3255 latest_session_consumed_total =
3256 previous_session_consumed_total +
3257 latest_sample.channel_total_consumed;
ab0ee2ca
JG
3258 }
3259
e8360425
JD
3260 channel_info->session_info->consumed_data_size =
3261 latest_session_consumed_total;
3262
ab0ee2ca
JG
3263 /* Find triggers associated with this channel. */
3264 cds_lfht_lookup(state->channel_triggers_ht,
3265 hash_channel_key(&latest_sample.key),
3266 match_channel_trigger_list,
3267 &latest_sample.key,
3268 &iter);
3269 node = cds_lfht_iter_get_node(&iter);
e0b5f87b 3270 if (caa_likely(!node)) {
ab0ee2ca
JG
3271 goto end_unlock;
3272 }
3273
3274 trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
3275 channel_triggers_ht_node);
3276 cds_list_for_each_entry(trigger_list_element, &trigger_list->list,
3277 node) {
9b63a4aa
JG
3278 const struct lttng_condition *condition;
3279 const struct lttng_action *action;
3280 const struct lttng_trigger *trigger;
ab0ee2ca
JG
3281 struct notification_client_list *client_list;
3282 struct lttng_evaluation *evaluation = NULL;
3283
3284 trigger = trigger_list_element->trigger;
9b63a4aa 3285 condition = lttng_trigger_get_const_condition(trigger);
ab0ee2ca 3286 assert(condition);
9b63a4aa 3287 action = lttng_trigger_get_const_action(trigger);
ab0ee2ca
JG
3288
3289 /* Notify actions are the only type currently supported. */
9b63a4aa 3290 assert(lttng_action_get_type_const(action) ==
ab0ee2ca
JG
3291 LTTNG_ACTION_TYPE_NOTIFY);
3292
3293 /*
3294 * Check if any client is subscribed to the result of this
3295 * evaluation.
3296 */
ed327204
JG
3297 client_list = get_client_list_from_condition(state, condition);
3298 assert(client_list);
ab0ee2ca
JG
3299 if (cds_list_empty(&client_list->list)) {
3300 /*
3301 * No clients interested in the evaluation's result,
3302 * skip it.
3303 */
3304 continue;
3305 }
3306
ed327204 3307 ret = evaluate_buffer_condition(condition, &evaluation, state,
ab0ee2ca 3308 previous_sample_available ? &previous_sample : NULL,
e8360425
JD
3309 &latest_sample,
3310 previous_session_consumed_total,
3311 latest_session_consumed_total,
3312 channel_info);
3313 if (caa_unlikely(ret)) {
ab0ee2ca
JG
3314 goto end_unlock;
3315 }
3316
e8360425 3317 if (caa_likely(!evaluation)) {
ab0ee2ca
JG
3318 continue;
3319 }
3320
3321 /* Dispatch evaluation result to all clients. */
3322 ret = send_evaluation_to_clients(trigger_list_element->trigger,
3323 evaluation, client_list, state,
8abe313a
JG
3324 channel_info->session_info->uid,
3325 channel_info->session_info->gid);
3326 lttng_evaluation_destroy(evaluation);
e0b5f87b 3327 if (caa_unlikely(ret)) {
ab0ee2ca
JG
3328 goto end_unlock;
3329 }
3330 }
3331end_unlock:
3332 rcu_read_unlock();
3333end:
3334 return ret;
3335}
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