Clarify error message on "add context" failure
[lttng-tools.git] / src / bin / lttng-sessiond / agent.c
... / ...
CommitLineData
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 _LGPL_SOURCE
19#include <assert.h>
20#include <urcu/uatomic.h>
21
22#include <common/common.h>
23#include <common/sessiond-comm/agent.h>
24
25#include <common/compat/endian.h>
26
27#include "agent.h"
28#include "ust-app.h"
29#include "utils.h"
30#include "error.h"
31
32#define AGENT_RET_CODE_INDEX(code) (code - AGENT_RET_CODE_SUCCESS)
33
34/*
35 * Human readable agent return code.
36 */
37static const char *error_string_array[] = {
38 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_SUCCESS) ] = "Success",
39 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_INVALID) ] = "Invalid command",
40 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_UNKNOWN_NAME) ] = "Unknown logger name",
41
42 /* Last element */
43 [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_NR) ] = "Unknown code",
44};
45
46static
47void log_reply_code(uint32_t in_reply_ret_code)
48{
49 int level = PRINT_DBG3;
50 /*
51 * reply_ret_code and in_reply_ret_code are kept separate to have a
52 * sanitized value (used to retrieve the human readable string) and the
53 * original value which is logged as-is.
54 */
55 uint32_t reply_ret_code = in_reply_ret_code;
56
57 if (reply_ret_code < AGENT_RET_CODE_SUCCESS ||
58 reply_ret_code >= AGENT_RET_CODE_NR) {
59 reply_ret_code = AGENT_RET_CODE_NR;
60 level = PRINT_ERR;
61 }
62
63 LOG(level, "Agent replied with retcode: %s (%"PRIu32")",
64 error_string_array[AGENT_RET_CODE_INDEX(
65 reply_ret_code)],
66 in_reply_ret_code);
67}
68
69/*
70 * Match function for the events hash table lookup by name.
71 */
72static int ht_match_event_by_name(struct cds_lfht_node *node,
73 const void *_key)
74{
75 struct agent_event *event;
76 const struct agent_ht_key *key;
77
78 assert(node);
79 assert(_key);
80
81 event = caa_container_of(node, struct agent_event, node.node);
82 key = _key;
83
84 /* Match 1 elements of the key: name. */
85
86 /* Event name */
87 if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
88 goto no_match;
89 }
90 /* Match. */
91 return 1;
92
93no_match:
94 return 0;
95}
96
97/*
98 * Match function for the events hash table lookup by name and loglevel.
99 */
100static int ht_match_event(struct cds_lfht_node *node,
101 const void *_key)
102{
103 struct agent_event *event;
104 const struct agent_ht_key *key;
105 int ll_match;
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 /* Event loglevel value and type. */
121 ll_match = loglevels_match(event->loglevel_type,
122 event->loglevel_value, key->loglevel_type,
123 key->loglevel_value, LTTNG_EVENT_LOGLEVEL_ALL);
124
125 if (!ll_match) {
126 goto no_match;
127 }
128
129 /* Filter expression */
130 if (strncmp(event->filter_expression, key->filter_expression,
131 strlen(event->filter_expression)) != 0) {
132 goto no_match;
133 }
134
135 return 1;
136
137no_match:
138 return 0;
139}
140
141/*
142 * Add unique agent event based on the event name and loglevel.
143 */
144static void add_unique_agent_event(struct lttng_ht *ht,
145 struct agent_event *event)
146{
147 struct cds_lfht_node *node_ptr;
148 struct agent_ht_key key;
149
150 assert(ht);
151 assert(ht->ht);
152 assert(event);
153
154 key.name = event->name;
155 key.loglevel_value = event->loglevel_value;
156 key.loglevel_type = event->loglevel_type;
157 key.filter_expression = event->filter_expression;
158
159 node_ptr = cds_lfht_add_unique(ht->ht,
160 ht->hash_fct(event->node.key, lttng_ht_seed),
161 ht_match_event, &key, &event->node.node);
162 assert(node_ptr == &event->node.node);
163}
164
165/*
166 * URCU delayed agent event reclaim.
167 */
168static void destroy_event_agent_rcu(struct rcu_head *head)
169{
170 struct lttng_ht_node_str *node =
171 caa_container_of(head, struct lttng_ht_node_str, head);
172 struct agent_event *event =
173 caa_container_of(node, struct agent_event, node);
174
175 agent_destroy_event(event);
176}
177
178/*
179 * URCU delayed agent app reclaim.
180 */
181static void destroy_app_agent_rcu(struct rcu_head *head)
182{
183 struct lttng_ht_node_ulong *node =
184 caa_container_of(head, struct lttng_ht_node_ulong, head);
185 struct agent_app *app =
186 caa_container_of(node, struct agent_app, node);
187
188 free(app);
189}
190
191/*
192 * Communication with the agent. Send the message header to the given socket in
193 * big endian.
194 *
195 * Return 0 on success or else a negative errno message of sendmsg() op.
196 */
197static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
198 uint32_t cmd, uint32_t cmd_version)
199{
200 int ret;
201 ssize_t size;
202 struct lttcomm_agent_hdr msg;
203
204 assert(sock);
205
206 memset(&msg, 0, sizeof(msg));
207 msg.data_size = htobe64(data_size);
208 msg.cmd = htobe32(cmd);
209 msg.cmd_version = htobe32(cmd_version);
210
211 size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
212 if (size < sizeof(msg)) {
213 ret = -errno;
214 goto error;
215 }
216 ret = 0;
217
218error:
219 return ret;
220}
221
222/*
223 * Communication call with the agent. Send the payload to the given socket. The
224 * header MUST be sent prior to this call.
225 *
226 * Return 0 on success or else a negative errno value of sendmsg() op.
227 */
228static int send_payload(struct lttcomm_sock *sock, void *data,
229 size_t size)
230{
231 int ret;
232 ssize_t len;
233
234 assert(sock);
235 assert(data);
236
237 len = sock->ops->sendmsg(sock, data, size, 0);
238 if (len < size) {
239 ret = -errno;
240 goto error;
241 }
242 ret = 0;
243
244error:
245 return ret;
246}
247
248/*
249 * Communication call with the agent. Receive reply from the agent using the
250 * given socket.
251 *
252 * Return 0 on success or else a negative errno value from recvmsg() op.
253 */
254static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
255{
256 int ret;
257 ssize_t len;
258
259 assert(sock);
260 assert(buf);
261
262 len = sock->ops->recvmsg(sock, buf, size, 0);
263 if (len < size) {
264 ret = -errno;
265 goto error;
266 }
267 ret = 0;
268
269error:
270 return ret;
271}
272
273/*
274 * Internal event listing for a given app. Populate events.
275 *
276 * Return number of element in the list or else a negative LTTNG_ERR* code.
277 * On success, the caller is responsible for freeing the memory
278 * allocated for "events".
279 */
280static ssize_t list_events(struct agent_app *app, struct lttng_event **events)
281{
282 int ret, i, len = 0, offset = 0;
283 uint32_t nb_event;
284 size_t data_size;
285 uint32_t reply_ret_code;
286 struct lttng_event *tmp_events = NULL;
287 struct lttcomm_agent_list_reply *reply = NULL;
288 struct lttcomm_agent_list_reply_hdr reply_hdr;
289
290 assert(app);
291 assert(app->sock);
292 assert(events);
293
294 DBG2("Agent listing events for app pid: %d and socket %d", app->pid,
295 app->sock->fd);
296
297 ret = send_header(app->sock, 0, AGENT_CMD_LIST, 0);
298 if (ret < 0) {
299 goto error_io;
300 }
301
302 /* Get list header so we know how much we'll receive. */
303 ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
304 if (ret < 0) {
305 goto error_io;
306 }
307
308 reply_ret_code = be32toh(reply_hdr.ret_code);
309 log_reply_code(reply_ret_code);
310 switch (reply_ret_code) {
311 case AGENT_RET_CODE_SUCCESS:
312 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
313 break;
314 default:
315 ret = LTTNG_ERR_UNK;
316 goto error;
317 }
318
319 reply = zmalloc(data_size);
320 if (!reply) {
321 ret = LTTNG_ERR_NOMEM;
322 goto error;
323 }
324
325 /* Get the list with the appropriate data size. */
326 ret = recv_reply(app->sock, reply, data_size);
327 if (ret < 0) {
328 goto error_io;
329 }
330
331 nb_event = be32toh(reply->nb_event);
332 tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
333 if (!tmp_events) {
334 ret = LTTNG_ERR_NOMEM;
335 goto error;
336 }
337
338 for (i = 0; i < nb_event; i++) {
339 offset += len;
340 strncpy(tmp_events[i].name, reply->payload + offset,
341 sizeof(tmp_events[i].name));
342 tmp_events[i].pid = app->pid;
343 tmp_events[i].enabled = -1;
344 len = strlen(reply->payload + offset) + 1;
345 }
346
347 *events = tmp_events;
348
349 free(reply);
350 return nb_event;
351
352error_io:
353 ret = LTTNG_ERR_UST_LIST_FAIL;
354error:
355 free(reply);
356 free(tmp_events);
357 return -ret;
358
359}
360
361/*
362 * Internal enable agent event on a agent application. This function
363 * communicates with the agent to enable a given event.
364 *
365 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
366 */
367static int enable_event(struct agent_app *app, struct agent_event *event)
368{
369 int ret;
370 char *bytes_to_send;
371 uint64_t data_size;
372 size_t filter_expression_length;
373 uint32_t reply_ret_code;
374 struct lttcomm_agent_enable msg;
375 struct lttcomm_agent_generic_reply reply;
376
377 assert(app);
378 assert(app->sock);
379 assert(event);
380
381 DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
382 app->pid, app->sock->fd);
383
384 /*
385 * Calculate the payload's size, which is the fixed-size struct followed
386 * by the variable-length filter expression (+1 for the ending \0).
387 */
388 if (!event->filter_expression) {
389 filter_expression_length = 0;
390 } else {
391 filter_expression_length = strlen(event->filter_expression) + 1;
392 }
393 data_size = sizeof(msg) + filter_expression_length;
394
395 ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
396 if (ret < 0) {
397 goto error_io;
398 }
399
400 memset(&msg, 0, sizeof(msg));
401 msg.loglevel_value = htobe32(event->loglevel_value);
402 msg.loglevel_type = htobe32(event->loglevel_type);
403 strncpy(msg.name, event->name, sizeof(msg.name));
404 msg.filter_expression_length = htobe32(filter_expression_length);
405
406 bytes_to_send = zmalloc(data_size);
407 if (!bytes_to_send) {
408 ret = LTTNG_ERR_NOMEM;
409 goto error;
410 }
411
412 memcpy(bytes_to_send, &msg, sizeof(msg));
413 if (filter_expression_length > 0) {
414 memcpy(bytes_to_send + sizeof(msg), event->filter_expression,
415 filter_expression_length);
416 }
417
418 ret = send_payload(app->sock, bytes_to_send, data_size);
419 free(bytes_to_send);
420 if (ret < 0) {
421 goto error_io;
422 }
423
424 ret = recv_reply(app->sock, &reply, sizeof(reply));
425 if (ret < 0) {
426 goto error_io;
427 }
428
429 reply_ret_code = be32toh(reply.ret_code);
430 log_reply_code(reply_ret_code);
431 switch (reply_ret_code) {
432 case AGENT_RET_CODE_SUCCESS:
433 break;
434 case AGENT_RET_CODE_UNKNOWN_NAME:
435 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
436 goto error;
437 default:
438 ret = LTTNG_ERR_UNK;
439 goto error;
440 }
441
442 return LTTNG_OK;
443
444error_io:
445 ret = LTTNG_ERR_UST_ENABLE_FAIL;
446error:
447 return ret;
448}
449
450/*
451 * Internal disable agent event call on a agent application. This function
452 * communicates with the agent to disable a given event.
453 *
454 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
455 */
456static int disable_event(struct agent_app *app, struct agent_event *event)
457{
458 int ret;
459 uint64_t data_size;
460 uint32_t reply_ret_code;
461 struct lttcomm_agent_disable msg;
462 struct lttcomm_agent_generic_reply reply;
463
464 assert(app);
465 assert(app->sock);
466 assert(event);
467
468 DBG2("Agent disabling event %s for app pid: %d and socket %d", event->name,
469 app->pid, app->sock->fd);
470
471 data_size = sizeof(msg);
472
473 ret = send_header(app->sock, data_size, AGENT_CMD_DISABLE, 0);
474 if (ret < 0) {
475 goto error_io;
476 }
477
478 memset(&msg, 0, sizeof(msg));
479 strncpy(msg.name, event->name, sizeof(msg.name));
480 ret = send_payload(app->sock, &msg, sizeof(msg));
481 if (ret < 0) {
482 goto error_io;
483 }
484
485 ret = recv_reply(app->sock, &reply, sizeof(reply));
486 if (ret < 0) {
487 goto error_io;
488 }
489
490 reply_ret_code = be32toh(reply.ret_code);
491 log_reply_code(reply_ret_code);
492 switch (reply_ret_code) {
493 case AGENT_RET_CODE_SUCCESS:
494 break;
495 case AGENT_RET_CODE_UNKNOWN_NAME:
496 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
497 goto error;
498 default:
499 ret = LTTNG_ERR_UNK;
500 goto error;
501 }
502
503 return LTTNG_OK;
504
505error_io:
506 ret = LTTNG_ERR_UST_DISABLE_FAIL;
507error:
508 return ret;
509}
510
511/*
512 * Send back the registration DONE command to a given agent application.
513 *
514 * Return 0 on success or else a negative value.
515 */
516int agent_send_registration_done(struct agent_app *app)
517{
518 assert(app);
519 assert(app->sock);
520
521 DBG("Agent sending registration done to app socket %d", app->sock->fd);
522
523 return send_header(app->sock, 0, AGENT_CMD_REG_DONE, 0);
524}
525
526/*
527 * Enable agent event on every agent applications registered with the session
528 * daemon.
529 *
530 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
531 */
532int agent_enable_event(struct agent_event *event,
533 enum lttng_domain_type domain)
534{
535 int ret;
536 struct agent_app *app;
537 struct lttng_ht_iter iter;
538
539 assert(event);
540
541 rcu_read_lock();
542
543 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
544 node.node) {
545 if (app->domain != domain) {
546 continue;
547 }
548
549 /* Enable event on agent application through TCP socket. */
550 ret = enable_event(app, event);
551 if (ret != LTTNG_OK) {
552 goto error;
553 }
554 }
555
556 event->enabled = 1;
557 ret = LTTNG_OK;
558
559error:
560 rcu_read_unlock();
561 return ret;
562}
563
564/*
565 * Disable agent event on every agent applications registered with the session
566 * daemon.
567 *
568 * Return LTTNG_OK on success or else a LTTNG_ERR* code.
569 */
570int agent_disable_event(struct agent_event *event,
571 enum lttng_domain_type domain)
572{
573 int ret = LTTNG_OK;
574 struct agent_app *app;
575 struct lttng_ht_iter iter;
576
577 assert(event);
578 if (!event->enabled) {
579 goto end;
580 }
581
582 rcu_read_lock();
583
584 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
585 node.node) {
586 if (app->domain != domain) {
587 continue;
588 }
589
590 /* Enable event on agent application through TCP socket. */
591 ret = disable_event(app, event);
592 if (ret != LTTNG_OK) {
593 goto error;
594 }
595 }
596
597 event->enabled = 0;
598
599error:
600 rcu_read_unlock();
601end:
602 return ret;
603}
604
605/*
606 * Ask every agent for the list of possible event. Events is allocated with the
607 * events of every agent application.
608 *
609 * Return the number of events or else a negative value.
610 */
611int agent_list_events(struct lttng_event **events,
612 enum lttng_domain_type domain)
613{
614 int ret;
615 size_t nbmem, count = 0;
616 struct agent_app *app;
617 struct lttng_event *tmp_events = NULL;
618 struct lttng_ht_iter iter;
619
620 assert(events);
621
622 DBG2("Agent listing events for domain %d", domain);
623
624 nbmem = UST_APP_EVENT_LIST_SIZE;
625 tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
626 if (!tmp_events) {
627 PERROR("zmalloc agent list events");
628 ret = -ENOMEM;
629 goto error;
630 }
631
632 rcu_read_lock();
633 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
634 node.node) {
635 ssize_t nb_ev;
636 struct lttng_event *agent_events;
637
638 /* Skip domain not asked by the list. */
639 if (app->domain != domain) {
640 continue;
641 }
642
643 nb_ev = list_events(app, &agent_events);
644 if (nb_ev < 0) {
645 ret = nb_ev;
646 goto error_unlock;
647 }
648
649 if (count + nb_ev > nbmem) {
650 /* In case the realloc fails, we free the memory */
651 struct lttng_event *new_tmp_events;
652 size_t new_nbmem;
653
654 new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
655 DBG2("Reallocating agent event list from %zu to %zu entries",
656 nbmem, new_nbmem);
657 new_tmp_events = realloc(tmp_events,
658 new_nbmem * sizeof(*new_tmp_events));
659 if (!new_tmp_events) {
660 PERROR("realloc agent events");
661 ret = -ENOMEM;
662 free(agent_events);
663 goto error_unlock;
664 }
665 /* Zero the new memory */
666 memset(new_tmp_events + nbmem, 0,
667 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
668 nbmem = new_nbmem;
669 tmp_events = new_tmp_events;
670 }
671 memcpy(tmp_events + count, agent_events,
672 nb_ev * sizeof(*tmp_events));
673 free(agent_events);
674 count += nb_ev;
675 }
676 rcu_read_unlock();
677
678 ret = count;
679 *events = tmp_events;
680 return ret;
681
682error_unlock:
683 rcu_read_unlock();
684error:
685 free(tmp_events);
686 return ret;
687}
688
689/*
690 * Create a agent app object using the given PID.
691 *
692 * Return newly allocated object or else NULL on error.
693 */
694struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
695 struct lttcomm_sock *sock)
696{
697 struct agent_app *app;
698
699 assert(sock);
700
701 app = zmalloc(sizeof(*app));
702 if (!app) {
703 PERROR("zmalloc agent create");
704 goto error;
705 }
706
707 app->pid = pid;
708 app->domain = domain;
709 app->sock = sock;
710 lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
711
712error:
713 return app;
714}
715
716/*
717 * Lookup agent app by socket in the global hash table.
718 *
719 * RCU read side lock MUST be acquired.
720 *
721 * Return object if found else NULL.
722 */
723struct agent_app *agent_find_app_by_sock(int sock)
724{
725 struct lttng_ht_node_ulong *node;
726 struct lttng_ht_iter iter;
727 struct agent_app *app;
728
729 assert(sock >= 0);
730
731 lttng_ht_lookup(agent_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
732 node = lttng_ht_iter_get_node_ulong(&iter);
733 if (node == NULL) {
734 goto error;
735 }
736 app = caa_container_of(node, struct agent_app, node);
737
738 DBG3("Agent app pid %d found by sock %d.", app->pid, sock);
739 return app;
740
741error:
742 DBG3("Agent app NOT found by sock %d.", sock);
743 return NULL;
744}
745
746/*
747 * Add agent application object to the global hash table.
748 */
749void agent_add_app(struct agent_app *app)
750{
751 assert(app);
752
753 DBG3("Agent adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
754 lttng_ht_add_unique_ulong(agent_apps_ht_by_sock, &app->node);
755}
756
757/*
758 * Delete agent application from the global hash table.
759 *
760 * rcu_read_lock() must be held by the caller.
761 */
762void agent_delete_app(struct agent_app *app)
763{
764 int ret;
765 struct lttng_ht_iter iter;
766
767 assert(app);
768
769 DBG3("Agent deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
770
771 iter.iter.node = &app->node.node;
772 ret = lttng_ht_del(agent_apps_ht_by_sock, &iter);
773 assert(!ret);
774}
775
776/*
777 * Destroy an agent application object by detaching it from its corresponding
778 * UST app if one is connected by closing the socket. Finally, perform a
779 * delayed memory reclaim.
780 */
781void agent_destroy_app(struct agent_app *app)
782{
783 assert(app);
784
785 if (app->sock) {
786 app->sock->ops->close(app->sock);
787 lttcomm_destroy_sock(app->sock);
788 }
789
790 call_rcu(&app->node.head, destroy_app_agent_rcu);
791}
792
793/*
794 * Initialize an already allocated agent object.
795 *
796 * Return 0 on success or else a negative errno value.
797 */
798int agent_init(struct agent *agt)
799{
800 int ret;
801
802 assert(agt);
803
804 agt->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
805 if (!agt->events) {
806 ret = -ENOMEM;
807 goto error;
808 }
809 lttng_ht_node_init_u64(&agt->node, agt->domain);
810
811 return 0;
812
813error:
814 return ret;
815}
816
817/*
818 * Add agent object to the given hash table.
819 */
820void agent_add(struct agent *agt, struct lttng_ht *ht)
821{
822 assert(agt);
823 assert(ht);
824
825 DBG3("Agent adding from domain %d", agt->domain);
826
827 lttng_ht_add_unique_u64(ht, &agt->node);
828}
829
830/*
831 * Create an agent object for the given domain.
832 *
833 * Return the allocated agent or NULL on error.
834 */
835struct agent *agent_create(enum lttng_domain_type domain)
836{
837 int ret;
838 struct agent *agt;
839
840 agt = zmalloc(sizeof(struct agent));
841 if (!agt) {
842 goto error;
843 }
844 agt->domain = domain;
845
846 ret = agent_init(agt);
847 if (ret < 0) {
848 free(agt);
849 agt = NULL;
850 goto error;
851 }
852
853error:
854 return agt;
855}
856
857/*
858 * Create a newly allocated agent event data structure.
859 * Ownership of filter_expression is taken.
860 *
861 * Return a new object else NULL on error.
862 */
863struct agent_event *agent_create_event(const char *name,
864 enum lttng_loglevel_type loglevel_type, int loglevel_value,
865 struct lttng_filter_bytecode *filter, char *filter_expression)
866{
867 struct agent_event *event = NULL;
868
869 DBG3("Agent create new event with name %s, loglevel type %d, \
870 loglevel value %d and filter %s",
871 name, loglevel_type, loglevel_value,
872 filter_expression ? filter_expression : "NULL");
873
874 if (!name) {
875 ERR("Failed to create agent event; no name provided.");
876 goto error;
877 }
878
879 event = zmalloc(sizeof(*event));
880 if (!event) {
881 goto error;
882 }
883
884 strncpy(event->name, name, sizeof(event->name));
885 event->name[sizeof(event->name) - 1] = '\0';
886 lttng_ht_node_init_str(&event->node, event->name);
887
888 event->loglevel_value = loglevel_value;
889 event->loglevel_type = loglevel_type;
890 event->filter = filter;
891 event->filter_expression = filter_expression;
892error:
893 return event;
894}
895
896/*
897 * Unique add of a agent event to an agent object.
898 */
899void agent_add_event(struct agent_event *event, struct agent *agt)
900{
901 assert(event);
902 assert(agt);
903 assert(agt->events);
904
905 DBG3("Agent adding event %s", event->name);
906 add_unique_agent_event(agt->events, event);
907 agt->being_used = 1;
908}
909
910/*
911 * Find multiple agent events sharing the given name.
912 *
913 * RCU read side lock MUST be acquired. It must be held for the
914 * duration of the iteration.
915 *
916 * Sets the given iterator.
917 */
918void agent_find_events_by_name(const char *name, struct agent *agt,
919 struct lttng_ht_iter* iter)
920{
921 struct lttng_ht *ht;
922 struct agent_ht_key key;
923
924 assert(name);
925 assert(agt);
926 assert(agt->events);
927 assert(iter);
928
929 ht = agt->events;
930 key.name = name;
931
932 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
933 ht_match_event_by_name, &key, &iter->iter);
934}
935
936/*
937 * Get the next agent event duplicate by name. This should be called
938 * after a call to agent_find_events_by_name() to iterate on events.
939 *
940 * The RCU read lock must be held during the iteration and for as long
941 * as the object the iterator points to remains in use.
942 */
943void agent_event_next_duplicate(const char *name,
944 struct agent *agt, struct lttng_ht_iter* iter)
945{
946 struct agent_ht_key key;
947
948 key.name = name;
949
950 cds_lfht_next_duplicate(agt->events->ht, ht_match_event_by_name,
951 &key, &iter->iter);
952}
953
954/*
955 * Find a agent event in the given agent using name, loglevel and filter.
956 *
957 * RCU read side lock MUST be acquired. It must be kept for as long as
958 * the returned agent_event is used.
959 *
960 * Return object if found else NULL.
961 */
962struct agent_event *agent_find_event(const char *name,
963 enum lttng_loglevel_type loglevel_type, int loglevel_value,
964 char *filter_expression, struct agent *agt)
965{
966 struct lttng_ht_node_str *node;
967 struct lttng_ht_iter iter;
968 struct lttng_ht *ht;
969 struct agent_ht_key key;
970
971 assert(name);
972 assert(agt);
973 assert(agt->events);
974
975 ht = agt->events;
976 key.name = name;
977 key.loglevel_value = loglevel_value;
978 key.loglevel_type = loglevel_type;
979 key.filter_expression = filter_expression;
980
981 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
982 ht_match_event, &key, &iter.iter);
983 node = lttng_ht_iter_get_node_str(&iter);
984 if (node == NULL) {
985 goto error;
986 }
987
988 DBG3("Agent event found %s.", name);
989 return caa_container_of(node, struct agent_event, node);
990
991error:
992 DBG3("Agent event NOT found %s.", name);
993 return NULL;
994}
995
996/*
997 * Free given agent event. This event must not be globally visible at this
998 * point (only expected to be used on failure just after event creation). After
999 * this call, the pointer is not usable anymore.
1000 */
1001void agent_destroy_event(struct agent_event *event)
1002{
1003 assert(event);
1004
1005 free(event->filter);
1006 free(event->filter_expression);
1007 free(event->exclusion);
1008 free(event);
1009}
1010
1011/*
1012 * Destroy an agent completely.
1013 */
1014void agent_destroy(struct agent *agt)
1015{
1016 struct lttng_ht_node_str *node;
1017 struct lttng_ht_iter iter;
1018
1019 assert(agt);
1020
1021 DBG3("Agent destroy");
1022
1023 rcu_read_lock();
1024 cds_lfht_for_each_entry(agt->events->ht, &iter.iter, node, node) {
1025 int ret;
1026 struct agent_event *event;
1027
1028 /*
1029 * When destroying an event, we have to try to disable it on the agent
1030 * side so the event stops generating data. The return value is not
1031 * important since we have to continue anyway destroying the object.
1032 */
1033 event = caa_container_of(node, struct agent_event, node);
1034 (void) agent_disable_event(event, agt->domain);
1035
1036 ret = lttng_ht_del(agt->events, &iter);
1037 assert(!ret);
1038 call_rcu(&node->head, destroy_event_agent_rcu);
1039 }
1040 rcu_read_unlock();
1041
1042 ht_cleanup_push(agt->events);
1043 free(agt);
1044}
1045
1046/*
1047 * Allocate agent_apps_ht_by_sock.
1048 */
1049int agent_app_ht_alloc(void)
1050{
1051 int ret = 0;
1052
1053 agent_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1054 if (!agent_apps_ht_by_sock) {
1055 ret = -1;
1056 }
1057
1058 return ret;
1059}
1060
1061/*
1062 * Destroy a agent application by socket.
1063 */
1064void agent_destroy_app_by_sock(int sock)
1065{
1066 struct agent_app *app;
1067
1068 assert(sock >= 0);
1069
1070 /*
1071 * Not finding an application is a very important error that should NEVER
1072 * happen. The hash table deletion is ONLY done through this call when the
1073 * main sessiond thread is torn down.
1074 */
1075 rcu_read_lock();
1076 app = agent_find_app_by_sock(sock);
1077 assert(app);
1078
1079 /* RCU read side lock is assumed to be held by this function. */
1080 agent_delete_app(app);
1081
1082 /* The application is freed in a RCU call but the socket is closed here. */
1083 agent_destroy_app(app);
1084 rcu_read_unlock();
1085}
1086
1087/*
1088 * Clean-up the agent app hash table and destroy it.
1089 */
1090void agent_app_ht_clean(void)
1091{
1092 struct lttng_ht_node_ulong *node;
1093 struct lttng_ht_iter iter;
1094
1095 if (!agent_apps_ht_by_sock) {
1096 return;
1097 }
1098 rcu_read_lock();
1099 cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) {
1100 struct agent_app *app;
1101
1102 app = caa_container_of(node, struct agent_app, node);
1103 agent_destroy_app_by_sock(app->sock->fd);
1104 }
1105 rcu_read_unlock();
1106
1107 lttng_ht_destroy(agent_apps_ht_by_sock);
1108}
1109
1110/*
1111 * Update a agent application (given socket) using the given agent.
1112 *
1113 * Note that this function is most likely to be used with a tracing session
1114 * thus the caller should make sure to hold the appropriate lock(s).
1115 */
1116void agent_update(struct agent *agt, int sock)
1117{
1118 int ret;
1119 struct agent_app *app;
1120 struct agent_event *event;
1121 struct lttng_ht_iter iter;
1122
1123 assert(agt);
1124 assert(sock >= 0);
1125
1126 DBG("Agent updating app socket %d", sock);
1127
1128 rcu_read_lock();
1129 cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
1130 /* Skip event if disabled. */
1131 if (!event->enabled) {
1132 continue;
1133 }
1134
1135 app = agent_find_app_by_sock(sock);
1136 /*
1137 * We are in the registration path thus if the application is gone,
1138 * there is a serious code flow error.
1139 */
1140 assert(app);
1141
1142 ret = enable_event(app, event);
1143 if (ret != LTTNG_OK) {
1144 DBG2("Agent update unable to enable event %s on app pid: %d sock %d",
1145 event->name, app->pid, app->sock->fd);
1146 /* Let's try the others here and don't assume the app is dead. */
1147 continue;
1148 }
1149 }
1150 rcu_read_unlock();
1151}
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