adca25ac1c0ea551a8c2b540917ab5e87a9394b0
[lttng-tools.git] / src / bin / lttng-sessiond / agent.c
1 /*
2 * Copyright (C) 2013 - David Goulet <dgoulet@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 _GNU_SOURCE
19 #define _LGPL_SOURCE
20 #include <assert.h>
21 #include <urcu/uatomic.h>
22
23 #include <common/common.h>
24 #include <common/sessiond-comm/agent.h>
25
26 #include <common/compat/endian.h>
27
28 #include "agent.h"
29 #include "ust-app.h"
30 #include "utils.h"
31 #include "error.h"
32
33 #define AGENT_RET_CODE_INDEX(code) (code - AGENT_RET_CODE_SUCCESS)
34
35 /*
36 * Human readable agent return code.
37 */
38 static const char *error_string_array[] = {
39 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_SUCCESS) ] = "Success",
40 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_INVALID) ] = "Invalid command",
41 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_UNKNOWN_NAME) ] = "Unknown logger name",
42
43 /* Last element */
44 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_NR) ] = "Unknown code",
45 };
46
47 static
48 void log_reply_code(uint32_t in_reply_ret_code)
49 {
50 int level = PRINT_DBG3;
51 /*
52 * reply_ret_code and in_reply_ret_code are kept separate to have a
53 * sanitized value (used to retrieve the human readable string) and the
54 * original value which is logged as-is.
55 */
56 uint32_t reply_ret_code = in_reply_ret_code;
57
58 if (reply_ret_code < AGENT_RET_CODE_SUCCESS ||
59 reply_ret_code >= AGENT_RET_CODE_NR) {
60 reply_ret_code = AGENT_RET_CODE_NR;
61 level = PRINT_ERR;
62 }
63
64 LOG(level, "Agent replied with retcode: %s (%"PRIu32")",
65 error_string_array[AGENT_RET_CODE_INDEX(
66 reply_ret_code)],
67 in_reply_ret_code);
68 }
69
70 /*
71 * Match function for the events hash table lookup by name.
72 */
73 static int ht_match_event_by_name(struct cds_lfht_node *node,
74 const void *_key)
75 {
76 struct agent_event *event;
77 const struct agent_ht_key *key;
78
79 assert(node);
80 assert(_key);
81
82 event = caa_container_of(node, struct agent_event, node.node);
83 key = _key;
84
85 /* Match 1 elements of the key: name. */
86
87 /* Event name */
88 if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
89 goto no_match;
90 }
91 /* Match. */
92 return 1;
93
94 no_match:
95 return 0;
96 }
97
98 /*
99 * Match function for the events hash table lookup by name and loglevel.
100 */
101 static int ht_match_event(struct cds_lfht_node *node,
102 const void *_key)
103 {
104 struct agent_event *event;
105 const struct agent_ht_key *key;
106
107 assert(node);
108 assert(_key);
109
110 event = caa_container_of(node, struct agent_event, node.node);
111 key = _key;
112
113 /* Match 2 elements of the key: name and loglevel. */
114
115 /* Event name */
116 if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
117 goto no_match;
118 }
119
120 if (event->loglevel != key->loglevel) {
121 if (event->loglevel_type == LTTNG_EVENT_LOGLEVEL_ALL &&
122 key->loglevel == 0 && event->loglevel == -1) {
123 goto match;
124 }
125 goto no_match;
126 }
127 match:
128 return 1;
129
130 no_match:
131 return 0;
132 }
133
134 /*
135 * Add unique agent event based on the event name and loglevel.
136 */
137 static void add_unique_agent_event(struct lttng_ht *ht,
138 struct agent_event *event)
139 {
140 struct cds_lfht_node *node_ptr;
141 struct agent_ht_key key;
142
143 assert(ht);
144 assert(ht->ht);
145 assert(event);
146
147 key.name = event->name;
148 key.loglevel = event->loglevel;
149
150 node_ptr = cds_lfht_add_unique(ht->ht,
151 ht->hash_fct(event->node.key, lttng_ht_seed),
152 ht_match_event, &key, &event->node.node);
153 assert(node_ptr == &event->node.node);
154 }
155
156 /*
157 * URCU delayed agent event reclaim.
158 */
159 static void destroy_event_agent_rcu(struct rcu_head *head)
160 {
161 struct lttng_ht_node_str *node =
162 caa_container_of(head, struct lttng_ht_node_str, head);
163 struct agent_event *event =
164 caa_container_of(node, struct agent_event, node);
165
166 agent_destroy_event(event);
167 }
168
169 /*
170 * URCU delayed agent app reclaim.
171 */
172 static void destroy_app_agent_rcu(struct rcu_head *head)
173 {
174 struct lttng_ht_node_ulong *node =
175 caa_container_of(head, struct lttng_ht_node_ulong, head);
176 struct agent_app *app =
177 caa_container_of(node, struct agent_app, node);
178
179 free(app);
180 }
181
182 /*
183 * Communication with the agent. Send the message header to the given socket in
184 * big endian.
185 *
186 * Return 0 on success or else a negative errno message of sendmsg() op.
187 */
188 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
189 uint32_t cmd, uint32_t cmd_version)
190 {
191 int ret;
192 ssize_t size;
193 struct lttcomm_agent_hdr msg;
194
195 assert(sock);
196
197 memset(&msg, 0, sizeof(msg));
198 msg.data_size = htobe64(data_size);
199 msg.cmd = htobe32(cmd);
200 msg.cmd_version = htobe32(cmd_version);
201
202 size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
203 if (size < sizeof(msg)) {
204 ret = -errno;
205 goto error;
206 }
207 ret = 0;
208
209 error:
210 return ret;
211 }
212
213 /*
214 * Communication call with the agent. Send the payload to the given socket. The
215 * header MUST be sent prior to this call.
216 *
217 * Return 0 on success or else a negative errno value of sendmsg() op.
218 */
219 static int send_payload(struct lttcomm_sock *sock, void *data,
220 size_t size)
221 {
222 int ret;
223 ssize_t len;
224
225 assert(sock);
226 assert(data);
227
228 len = sock->ops->sendmsg(sock, data, size, 0);
229 if (len < size) {
230 ret = -errno;
231 goto error;
232 }
233 ret = 0;
234
235 error:
236 return ret;
237 }
238
239 /*
240 * Communication call with the agent. Receive reply from the agent using the
241 * given socket.
242 *
243 * Return 0 on success or else a negative errno value from recvmsg() op.
244 */
245 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
246 {
247 int ret;
248 ssize_t len;
249
250 assert(sock);
251 assert(buf);
252
253 len = sock->ops->recvmsg(sock, buf, size, 0);
254 if (len < size) {
255 ret = -errno;
256 goto error;
257 }
258 ret = 0;
259
260 error:
261 return ret;
262 }
263
264 /*
265 * Internal event listing for a given app. Populate events.
266 *
267 * Return number of element in the list or else a negative LTTNG_ERR* code.
268 * On success, the caller is responsible for freeing the memory
269 * allocated for "events".
270 */
271 static ssize_t list_events(struct agent_app *app, struct lttng_event **events)
272 {
273 int ret, i, len = 0, offset = 0;
274 uint32_t nb_event;
275 size_t data_size;
276 uint32_t reply_ret_code;
277 struct lttng_event *tmp_events = NULL;
278 struct lttcomm_agent_list_reply *reply = NULL;
279 struct lttcomm_agent_list_reply_hdr reply_hdr;
280
281 assert(app);
282 assert(app->sock);
283 assert(events);
284
285 DBG2("Agent listing events for app pid: %d and socket %d", app->pid,
286 app->sock->fd);
287
288 ret = send_header(app->sock, 0, AGENT_CMD_LIST, 0);
289 if (ret < 0) {
290 goto error_io;
291 }
292
293 /* Get list header so we know how much we'll receive. */
294 ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
295 if (ret < 0) {
296 goto error_io;
297 }
298
299 reply_ret_code = be32toh(reply_hdr.ret_code);
300 log_reply_code(reply_ret_code);
301 switch (reply_ret_code) {
302 case AGENT_RET_CODE_SUCCESS:
303 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
304 break;
305 default:
306 ret = LTTNG_ERR_UNK;
307 goto error;
308 }
309
310 reply = zmalloc(data_size);
311 if (!reply) {
312 ret = LTTNG_ERR_NOMEM;
313 goto error;
314 }
315
316 /* Get the list with the appropriate data size. */
317 ret = recv_reply(app->sock, reply, data_size);
318 if (ret < 0) {
319 goto error_io;
320 }
321
322 nb_event = be32toh(reply->nb_event);
323 tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
324 if (!tmp_events) {
325 ret = LTTNG_ERR_NOMEM;
326 goto error;
327 }
328
329 for (i = 0; i < nb_event; i++) {
330 offset += len;
331 strncpy(tmp_events[i].name, reply->payload + offset,
332 sizeof(tmp_events[i].name));
333 tmp_events[i].pid = app->pid;
334 tmp_events[i].enabled = -1;
335 len = strlen(reply->payload + offset) + 1;
336 }
337
338 *events = tmp_events;
339
340 free(reply);
341 return nb_event;
342
343 error_io:
344 ret = LTTNG_ERR_UST_LIST_FAIL;
345 error:
346 free(reply);
347 free(tmp_events);
348 return -ret;
349
350 }
351
352 /*
353 * Internal enable agent event on a agent application. This function
354 * communicates with the agent to enable a given event.
355 *
356 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
357 */
358 static int enable_event(struct agent_app *app, struct agent_event *event)
359 {
360 int ret;
361 uint64_t data_size;
362 uint32_t reply_ret_code;
363 struct lttcomm_agent_enable msg;
364 struct lttcomm_agent_generic_reply reply;
365
366 assert(app);
367 assert(app->sock);
368 assert(event);
369
370 DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
371 app->pid, app->sock->fd);
372
373 data_size = sizeof(msg);
374
375 ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
376 if (ret < 0) {
377 goto error_io;
378 }
379
380 memset(&msg, 0, sizeof(msg));
381 msg.loglevel = event->loglevel;
382 msg.loglevel_type = event->loglevel_type;
383 strncpy(msg.name, event->name, sizeof(msg.name));
384 ret = send_payload(app->sock, &msg, sizeof(msg));
385 if (ret < 0) {
386 goto error_io;
387 }
388
389 ret = recv_reply(app->sock, &reply, sizeof(reply));
390 if (ret < 0) {
391 goto error_io;
392 }
393
394 reply_ret_code = be32toh(reply.ret_code);
395 log_reply_code(reply_ret_code);
396 switch (reply_ret_code) {
397 case AGENT_RET_CODE_SUCCESS:
398 break;
399 case AGENT_RET_CODE_UNKNOWN_NAME:
400 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
401 goto error;
402 default:
403 ret = LTTNG_ERR_UNK;
404 goto error;
405 }
406
407 return LTTNG_OK;
408
409 error_io:
410 ret = LTTNG_ERR_UST_ENABLE_FAIL;
411 error:
412 return ret;
413 }
414
415 /*
416 * Internal disable agent event call on a agent application. This function
417 * communicates with the agent to disable a given event.
418 *
419 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
420 */
421 static int disable_event(struct agent_app *app, struct agent_event *event)
422 {
423 int ret;
424 uint64_t data_size;
425 uint32_t reply_ret_code;
426 struct lttcomm_agent_disable msg;
427 struct lttcomm_agent_generic_reply reply;
428
429 assert(app);
430 assert(app->sock);
431 assert(event);
432
433 DBG2("Agent disabling event %s for app pid: %d and socket %d", event->name,
434 app->pid, app->sock->fd);
435
436 data_size = sizeof(msg);
437
438 ret = send_header(app->sock, data_size, AGENT_CMD_DISABLE, 0);
439 if (ret < 0) {
440 goto error_io;
441 }
442
443 memset(&msg, 0, sizeof(msg));
444 strncpy(msg.name, event->name, sizeof(msg.name));
445 ret = send_payload(app->sock, &msg, sizeof(msg));
446 if (ret < 0) {
447 goto error_io;
448 }
449
450 ret = recv_reply(app->sock, &reply, sizeof(reply));
451 if (ret < 0) {
452 goto error_io;
453 }
454
455 reply_ret_code = be32toh(reply.ret_code);
456 log_reply_code(reply_ret_code);
457 switch (reply_ret_code) {
458 case AGENT_RET_CODE_SUCCESS:
459 break;
460 case AGENT_RET_CODE_UNKNOWN_NAME:
461 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
462 goto error;
463 default:
464 ret = LTTNG_ERR_UNK;
465 goto error;
466 }
467
468 return LTTNG_OK;
469
470 error_io:
471 ret = LTTNG_ERR_UST_DISABLE_FAIL;
472 error:
473 return ret;
474 }
475
476 /*
477 * Send back the registration DONE command to a given agent application.
478 *
479 * Return 0 on success or else a negative value.
480 */
481 int agent_send_registration_done(struct agent_app *app)
482 {
483 assert(app);
484 assert(app->sock);
485
486 DBG("Agent sending registration done to app socket %d", app->sock->fd);
487
488 return send_header(app->sock, 0, AGENT_CMD_REG_DONE, 0);
489 }
490
491 /*
492 * Enable agent event on every agent applications registered with the session
493 * daemon.
494 *
495 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
496 */
497 int agent_enable_event(struct agent_event *event,
498 enum lttng_domain_type domain)
499 {
500 int ret;
501 struct agent_app *app;
502 struct lttng_ht_iter iter;
503
504 assert(event);
505
506 rcu_read_lock();
507
508 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
509 node.node) {
510 if (app->domain != domain) {
511 continue;
512 }
513
514 /* Enable event on agent application through TCP socket. */
515 ret = enable_event(app, event);
516 if (ret != LTTNG_OK) {
517 goto error;
518 }
519 }
520
521 event->enabled = 1;
522 ret = LTTNG_OK;
523
524 error:
525 rcu_read_unlock();
526 return ret;
527 }
528
529 /*
530 * Disable agent event on every agent applications registered with the session
531 * daemon.
532 *
533 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
534 */
535 int agent_disable_event(struct agent_event *event,
536 enum lttng_domain_type domain)
537 {
538 int ret = LTTNG_OK;
539 struct agent_app *app;
540 struct lttng_ht_iter iter;
541
542 assert(event);
543 if (!event->enabled) {
544 goto end;
545 }
546
547 rcu_read_lock();
548
549 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
550 node.node) {
551 if (app->domain != domain) {
552 continue;
553 }
554
555 /* Enable event on agent application through TCP socket. */
556 ret = disable_event(app, event);
557 if (ret != LTTNG_OK) {
558 goto error;
559 }
560 }
561
562 event->enabled = 0;
563
564 error:
565 rcu_read_unlock();
566 end:
567 return ret;
568 }
569
570 /*
571 * Ask every agent for the list of possible event. Events is allocated with the
572 * events of every agent application.
573 *
574 * Return the number of events or else a negative value.
575 */
576 int agent_list_events(struct lttng_event **events,
577 enum lttng_domain_type domain)
578 {
579 int ret;
580 size_t nbmem, count = 0;
581 struct agent_app *app;
582 struct lttng_event *tmp_events = NULL;
583 struct lttng_ht_iter iter;
584
585 assert(events);
586
587 DBG2("Agent listing events for domain %d", domain);
588
589 nbmem = UST_APP_EVENT_LIST_SIZE;
590 tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
591 if (!tmp_events) {
592 PERROR("zmalloc agent list events");
593 ret = -ENOMEM;
594 goto error;
595 }
596
597 rcu_read_lock();
598 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
599 node.node) {
600 ssize_t nb_ev;
601 struct lttng_event *agent_events;
602
603 /* Skip domain not asked by the list. */
604 if (app->domain != domain) {
605 continue;
606 }
607
608 nb_ev = list_events(app, &agent_events);
609 if (nb_ev < 0) {
610 ret = nb_ev;
611 goto error_unlock;
612 }
613
614 if (count + nb_ev > nbmem) {
615 /* In case the realloc fails, we free the memory */
616 struct lttng_event *new_tmp_events;
617 size_t new_nbmem;
618
619 new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
620 DBG2("Reallocating agent event list from %zu to %zu entries",
621 nbmem, new_nbmem);
622 new_tmp_events = realloc(tmp_events,
623 new_nbmem * sizeof(*new_tmp_events));
624 if (!new_tmp_events) {
625 PERROR("realloc agent events");
626 ret = -ENOMEM;
627 free(agent_events);
628 goto error_unlock;
629 }
630 /* Zero the new memory */
631 memset(new_tmp_events + nbmem, 0,
632 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
633 nbmem = new_nbmem;
634 tmp_events = new_tmp_events;
635 }
636 memcpy(tmp_events + count, agent_events,
637 nb_ev * sizeof(*tmp_events));
638 free(agent_events);
639 count += nb_ev;
640 }
641 rcu_read_unlock();
642
643 ret = count;
644 *events = tmp_events;
645 return ret;
646
647 error_unlock:
648 rcu_read_unlock();
649 error:
650 free(tmp_events);
651 return ret;
652 }
653
654 /*
655 * Create a agent app object using the given PID.
656 *
657 * Return newly allocated object or else NULL on error.
658 */
659 struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
660 struct lttcomm_sock *sock)
661 {
662 struct agent_app *app;
663
664 assert(sock);
665
666 app = zmalloc(sizeof(*app));
667 if (!app) {
668 PERROR("zmalloc agent create");
669 goto error;
670 }
671
672 app->pid = pid;
673 app->domain = domain;
674 app->sock = sock;
675 lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
676
677 error:
678 return app;
679 }
680
681 /*
682 * Lookup agent app by socket in the global hash table.
683 *
684 * RCU read side lock MUST be acquired.
685 *
686 * Return object if found else NULL.
687 */
688 struct agent_app *agent_find_app_by_sock(int sock)
689 {
690 struct lttng_ht_node_ulong *node;
691 struct lttng_ht_iter iter;
692 struct agent_app *app;
693
694 assert(sock >= 0);
695
696 lttng_ht_lookup(agent_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
697 node = lttng_ht_iter_get_node_ulong(&iter);
698 if (node == NULL) {
699 goto error;
700 }
701 app = caa_container_of(node, struct agent_app, node);
702
703 DBG3("Agent app pid %d found by sock %d.", app->pid, sock);
704 return app;
705
706 error:
707 DBG3("Agent app NOT found by sock %d.", sock);
708 return NULL;
709 }
710
711 /*
712 * Add agent application object to the global hash table.
713 */
714 void agent_add_app(struct agent_app *app)
715 {
716 assert(app);
717
718 DBG3("Agent adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
719 lttng_ht_add_unique_ulong(agent_apps_ht_by_sock, &app->node);
720 }
721
722 /*
723 * Delete agent application from the global hash table.
724 *
725 * rcu_read_lock() must be held by the caller.
726 */
727 void agent_delete_app(struct agent_app *app)
728 {
729 int ret;
730 struct lttng_ht_iter iter;
731
732 assert(app);
733
734 DBG3("Agent deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
735
736 iter.iter.node = &app->node.node;
737 ret = lttng_ht_del(agent_apps_ht_by_sock, &iter);
738 assert(!ret);
739 }
740
741 /*
742 * Destroy an agent application object by detaching it from its corresponding
743 * UST app if one is connected by closing the socket. Finally, perform a
744 * delayed memory reclaim.
745 */
746 void agent_destroy_app(struct agent_app *app)
747 {
748 assert(app);
749
750 if (app->sock) {
751 app->sock->ops->close(app->sock);
752 lttcomm_destroy_sock(app->sock);
753 }
754
755 call_rcu(&app->node.head, destroy_app_agent_rcu);
756 }
757
758 /*
759 * Initialize an already allocated agent object.
760 *
761 * Return 0 on success or else a negative errno value.
762 */
763 int agent_init(struct agent *agt)
764 {
765 int ret;
766
767 assert(agt);
768
769 agt->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
770 if (!agt->events) {
771 ret = -ENOMEM;
772 goto error;
773 }
774 lttng_ht_node_init_u64(&agt->node, agt->domain);
775
776 return 0;
777
778 error:
779 return ret;
780 }
781
782 /*
783 * Add agent object to the given hash table.
784 */
785 void agent_add(struct agent *agt, struct lttng_ht *ht)
786 {
787 assert(agt);
788 assert(ht);
789
790 DBG3("Agent adding from domain %d", agt->domain);
791
792 lttng_ht_add_unique_u64(ht, &agt->node);
793 }
794
795 /*
796 * Create an agent object for the given domain.
797 *
798 * Return the allocated agent or NULL on error.
799 */
800 struct agent *agent_create(enum lttng_domain_type domain)
801 {
802 int ret;
803 struct agent *agt;
804
805 agt = zmalloc(sizeof(struct agent));
806 if (!agt) {
807 goto error;
808 }
809 agt->domain = domain;
810
811 ret = agent_init(agt);
812 if (ret < 0) {
813 free(agt);
814 agt = NULL;
815 goto error;
816 }
817
818 error:
819 return agt;
820 }
821
822 /*
823 * Create a newly allocated agent event data structure.
824 * Ownership of filter_expression is taken.
825 *
826 * Return a new object else NULL on error.
827 */
828 struct agent_event *agent_create_event(const char *name,
829 int loglevel, enum lttng_loglevel_type loglevel_type,
830 struct lttng_filter_bytecode *filter, char *filter_expression)
831 {
832 struct agent_event *event = NULL;
833
834 DBG3("Agent create new event with name %s", name);
835
836 if (!name) {
837 ERR("Failed to create agent event; no name provided.");
838 goto error;
839 }
840
841 event = zmalloc(sizeof(*event));
842 if (!event) {
843 goto error;
844 }
845
846 strncpy(event->name, name, sizeof(event->name));
847 event->name[sizeof(event->name) - 1] = '\0';
848 lttng_ht_node_init_str(&event->node, event->name);
849
850 event->loglevel = loglevel;
851 event->loglevel_type = loglevel_type;
852 event->filter = filter;
853 event->filter_expression = filter_expression;
854 error:
855 return event;
856 }
857
858 /*
859 * Unique add of a agent event to an agent object.
860 */
861 void agent_add_event(struct agent_event *event, struct agent *agt)
862 {
863 assert(event);
864 assert(agt);
865 assert(agt->events);
866
867 DBG3("Agent adding event %s", event->name);
868 add_unique_agent_event(agt->events, event);
869 agt->being_used = 1;
870 }
871
872 /*
873 * Find a agent event in the given agent using name.
874 *
875 * RCU read side lock MUST be acquired.
876 *
877 * Return object if found else NULL.
878 */
879 struct agent_event *agent_find_event_by_name(const char *name,
880 struct agent *agt)
881 {
882 struct lttng_ht_node_str *node;
883 struct lttng_ht_iter iter;
884 struct lttng_ht *ht;
885 struct agent_ht_key key;
886
887 assert(name);
888 assert(agt);
889 assert(agt->events);
890
891 ht = agt->events;
892 key.name = name;
893
894 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
895 ht_match_event_by_name, &key, &iter.iter);
896 node = lttng_ht_iter_get_node_str(&iter);
897 if (node == NULL) {
898 goto error;
899 }
900
901 DBG3("Agent event found %s by name.", name);
902 return caa_container_of(node, struct agent_event, node);
903
904 error:
905 DBG3("Agent NOT found by name %s.", name);
906 return NULL;
907 }
908
909 /*
910 * Find a agent event in the given agent using name and loglevel.
911 *
912 * RCU read side lock MUST be acquired.
913 *
914 * Return object if found else NULL.
915 */
916 struct agent_event *agent_find_event(const char *name, int loglevel,
917 struct agent *agt)
918 {
919 struct lttng_ht_node_str *node;
920 struct lttng_ht_iter iter;
921 struct lttng_ht *ht;
922 struct agent_ht_key key;
923
924 assert(name);
925 assert(agt);
926 assert(agt->events);
927
928 ht = agt->events;
929 key.name = name;
930 key.loglevel = loglevel;
931
932 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
933 ht_match_event, &key, &iter.iter);
934 node = lttng_ht_iter_get_node_str(&iter);
935 if (node == NULL) {
936 goto error;
937 }
938
939 DBG3("Agent event found %s.", name);
940 return caa_container_of(node, struct agent_event, node);
941
942 error:
943 DBG3("Agent event NOT found %s.", name);
944 return NULL;
945 }
946
947 /*
948 * Free given agent event. This event must not be globally visible at this
949 * point (only expected to be used on failure just after event creation). After
950 * this call, the pointer is not usable anymore.
951 */
952 void agent_destroy_event(struct agent_event *event)
953 {
954 assert(event);
955
956 free(event->filter);
957 free(event->filter_expression);
958 free(event->exclusion);
959 free(event);
960 }
961
962 /*
963 * Destroy an agent completely. Note that the given pointer is NOT freed
964 * thus a reference to static or stack data can be passed to this function.
965 */
966 void agent_destroy(struct agent *agt)
967 {
968 struct lttng_ht_node_str *node;
969 struct lttng_ht_iter iter;
970
971 assert(agt);
972
973 DBG3("Agent destroy");
974
975 rcu_read_lock();
976 cds_lfht_for_each_entry(agt->events->ht, &iter.iter, node, node) {
977 int ret;
978 struct agent_event *event;
979
980 /*
981 * When destroying an event, we have to try to disable it on the agent
982 * side so the event stops generating data. The return value is not
983 * important since we have to continue anyway destroying the object.
984 */
985 event = caa_container_of(node, struct agent_event, node);
986 (void) agent_disable_event(event, agt->domain);
987
988 ret = lttng_ht_del(agt->events, &iter);
989 assert(!ret);
990 call_rcu(&node->head, destroy_event_agent_rcu);
991 }
992 rcu_read_unlock();
993
994 ht_cleanup_push(agt->events);
995 }
996
997 /*
998 * Allocate agent_apps_ht_by_sock.
999 */
1000 int agent_app_ht_alloc(void)
1001 {
1002 int ret = 0;
1003
1004 agent_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1005 if (!agent_apps_ht_by_sock) {
1006 ret = -1;
1007 }
1008
1009 return ret;
1010 }
1011
1012 /*
1013 * Destroy a agent application by socket.
1014 */
1015 void agent_destroy_app_by_sock(int sock)
1016 {
1017 struct agent_app *app;
1018
1019 assert(sock >= 0);
1020
1021 /*
1022 * Not finding an application is a very important error that should NEVER
1023 * happen. The hash table deletion is ONLY done through this call when the
1024 * main sessiond thread is torn down.
1025 */
1026 rcu_read_lock();
1027 app = agent_find_app_by_sock(sock);
1028 assert(app);
1029
1030 /* RCU read side lock is assumed to be held by this function. */
1031 agent_delete_app(app);
1032
1033 /* The application is freed in a RCU call but the socket is closed here. */
1034 agent_destroy_app(app);
1035 rcu_read_unlock();
1036 }
1037
1038 /*
1039 * Clean-up the agent app hash table and destroy it.
1040 */
1041 void agent_app_ht_clean(void)
1042 {
1043 struct lttng_ht_node_ulong *node;
1044 struct lttng_ht_iter iter;
1045
1046 if (!agent_apps_ht_by_sock) {
1047 return;
1048 }
1049 rcu_read_lock();
1050 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) {
1051 struct agent_app *app;
1052
1053 app = caa_container_of(node, struct agent_app, node);
1054 agent_destroy_app_by_sock(app->sock->fd);
1055 }
1056 rcu_read_unlock();
1057
1058 lttng_ht_destroy(agent_apps_ht_by_sock);
1059 }
1060
1061 /*
1062 * Update a agent application (given socket) using the given agent.
1063 *
1064 * Note that this function is most likely to be used with a tracing session
1065 * thus the caller should make sure to hold the appropriate lock(s).
1066 */
1067 void agent_update(struct agent *agt, int sock)
1068 {
1069 int ret;
1070 struct agent_app *app;
1071 struct agent_event *event;
1072 struct lttng_ht_iter iter;
1073
1074 assert(agt);
1075 assert(sock >= 0);
1076
1077 DBG("Agent updating app socket %d", sock);
1078
1079 rcu_read_lock();
1080 cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
1081 /* Skip event if disabled. */
1082 if (!event->enabled) {
1083 continue;
1084 }
1085
1086 app = agent_find_app_by_sock(sock);
1087 /*
1088 * We are in the registration path thus if the application is gone,
1089 * there is a serious code flow error.
1090 */
1091 assert(app);
1092
1093 ret = enable_event(app, event);
1094 if (ret != LTTNG_OK) {
1095 DBG2("Agent update unable to enable event %s on app pid: %d sock %d",
1096 event->name, app->pid, app->sock->fd);
1097 /* Let's try the others here and don't assume the app is dead. */
1098 continue;
1099 }
1100 }
1101 rcu_read_unlock();
1102 }
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