Fix: sessiond: kernel: invalid error code check
[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c
1 /*
2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #define _LGPL_SOURCE
9 #include <fcntl.h>
10 #include <stdlib.h>
11 #include <stdio.h>
12 #include <string.h>
13 #include <unistd.h>
14 #include <inttypes.h>
15 #include <sys/types.h>
16
17 #include <common/common.h>
18 #include <common/hashtable/utils.h>
19 #include <common/trace-chunk.h>
20 #include <common/kernel-ctl/kernel-ctl.h>
21 #include <common/kernel-ctl/kernel-ioctl.h>
22 #include <common/sessiond-comm/sessiond-comm.h>
23 #include <common/tracker.h>
24 #include <common/utils.h>
25 #include <lttng/event.h>
26 #include <lttng/lttng-error.h>
27 #include <lttng/tracker.h>
28
29 #include <lttng/userspace-probe.h>
30 #include <lttng/userspace-probe-internal.h>
31 #include <lttng/condition/on-event.h>
32 #include <lttng/condition/on-event-internal.h>
33 #include <lttng/event-rule/event-rule.h>
34 #include <lttng/event-rule/event-rule-internal.h>
35 #include <lttng/event-rule/userspace-probe-internal.h>
36
37 #include "event-notifier-error-accounting.h"
38 #include "lttng-sessiond.h"
39 #include "lttng-syscall.h"
40 #include "condition-internal.h"
41 #include "consumer.h"
42 #include "kernel.h"
43 #include "kernel-consumer.h"
44 #include "kern-modules.h"
45 #include "sessiond-config.h"
46 #include "utils.h"
47 #include "rotate.h"
48 #include "modprobe.h"
49 #include "tracker.h"
50 #include "notification-thread-commands.h"
51
52 /*
53 * Key used to reference a channel between the sessiond and the consumer. This
54 * is only read and updated with the session_list lock held.
55 */
56 static uint64_t next_kernel_channel_key;
57
58 static const char *module_proc_lttng = "/proc/lttng";
59
60 static int kernel_tracer_fd = -1;
61 static int kernel_tracer_event_notifier_group_fd = -1;
62 static int kernel_tracer_event_notifier_group_notification_fd = -1;
63 static struct cds_lfht *kernel_token_to_event_notifier_rule_ht;
64
65 /*
66 * Add context on a kernel channel.
67 *
68 * Assumes the ownership of ctx.
69 */
70 int kernel_add_channel_context(struct ltt_kernel_channel *chan,
71 struct ltt_kernel_context *ctx)
72 {
73 int ret;
74
75 assert(chan);
76 assert(ctx);
77
78 DBG("Adding context to channel %s", chan->channel->name);
79 ret = kernctl_add_context(chan->fd, &ctx->ctx);
80 if (ret < 0) {
81 switch (-ret) {
82 case ENOSYS:
83 /* Exists but not available for this kernel */
84 ret = LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE;
85 goto error;
86 case EEXIST:
87 /* If EEXIST, we just ignore the error */
88 ret = 0;
89 goto end;
90 default:
91 PERROR("add context ioctl");
92 ret = LTTNG_ERR_KERN_CONTEXT_FAIL;
93 goto error;
94 }
95 }
96 ret = 0;
97
98 end:
99 cds_list_add_tail(&ctx->list, &chan->ctx_list);
100 ctx->in_list = true;
101 ctx = NULL;
102 error:
103 if (ctx) {
104 trace_kernel_destroy_context(ctx);
105 }
106 return ret;
107 }
108
109 /*
110 * Create a new kernel session, register it to the kernel tracer and add it to
111 * the session daemon session.
112 */
113 int kernel_create_session(struct ltt_session *session)
114 {
115 int ret;
116 struct ltt_kernel_session *lks;
117
118 assert(session);
119
120 /* Allocate data structure */
121 lks = trace_kernel_create_session();
122 if (lks == NULL) {
123 ret = -1;
124 goto error;
125 }
126
127 /* Kernel tracer session creation */
128 ret = kernctl_create_session(kernel_tracer_fd);
129 if (ret < 0) {
130 PERROR("ioctl kernel create session");
131 goto error;
132 }
133
134 lks->fd = ret;
135 /* Prevent fd duplication after execlp() */
136 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
137 if (ret < 0) {
138 PERROR("fcntl session fd");
139 }
140
141 lks->id = session->id;
142 lks->consumer_fds_sent = 0;
143 session->kernel_session = lks;
144
145 DBG("Kernel session created (fd: %d)", lks->fd);
146
147 /*
148 * This is necessary since the creation time is present in the session
149 * name when it is generated.
150 */
151 if (session->has_auto_generated_name) {
152 ret = kernctl_session_set_name(lks->fd, DEFAULT_SESSION_NAME);
153 } else {
154 ret = kernctl_session_set_name(lks->fd, session->name);
155 }
156 if (ret) {
157 WARN("Could not set kernel session name for session %" PRIu64 " name: %s",
158 session->id, session->name);
159 }
160
161 ret = kernctl_session_set_creation_time(lks->fd, session->creation_time);
162 if (ret) {
163 WARN("Could not set kernel session creation time for session %" PRIu64 " name: %s",
164 session->id, session->name);
165 }
166
167 return 0;
168
169 error:
170 if (lks) {
171 trace_kernel_destroy_session(lks);
172 trace_kernel_free_session(lks);
173 }
174 return ret;
175 }
176
177 /*
178 * Create a kernel channel, register it to the kernel tracer and add it to the
179 * kernel session.
180 */
181 int kernel_create_channel(struct ltt_kernel_session *session,
182 struct lttng_channel *chan)
183 {
184 int ret;
185 struct ltt_kernel_channel *lkc;
186
187 assert(session);
188 assert(chan);
189
190 /* Allocate kernel channel */
191 lkc = trace_kernel_create_channel(chan);
192 if (lkc == NULL) {
193 goto error;
194 }
195
196 DBG3("Kernel create channel %s with attr: %d, %" PRIu64 ", %" PRIu64 ", %u, %u, %d, %d",
197 chan->name, lkc->channel->attr.overwrite,
198 lkc->channel->attr.subbuf_size, lkc->channel->attr.num_subbuf,
199 lkc->channel->attr.switch_timer_interval, lkc->channel->attr.read_timer_interval,
200 lkc->channel->attr.live_timer_interval, lkc->channel->attr.output);
201
202 /* Kernel tracer channel creation */
203 ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
204 if (ret < 0) {
205 PERROR("ioctl kernel create channel");
206 goto error;
207 }
208
209 /* Setup the channel fd */
210 lkc->fd = ret;
211 /* Prevent fd duplication after execlp() */
212 ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
213 if (ret < 0) {
214 PERROR("fcntl session fd");
215 }
216
217 /* Add channel to session */
218 cds_list_add(&lkc->list, &session->channel_list.head);
219 session->channel_count++;
220 lkc->session = session;
221 lkc->key = ++next_kernel_channel_key;
222
223 DBG("Kernel channel %s created (fd: %d, key: %" PRIu64 ")",
224 lkc->channel->name, lkc->fd, lkc->key);
225
226 return 0;
227
228 error:
229 if (lkc) {
230 free(lkc->channel);
231 free(lkc);
232 }
233 return -1;
234 }
235
236 /*
237 * Create a kernel event notifier group, register it to the kernel tracer and
238 * add it to the kernel session.
239 */
240 static int kernel_create_event_notifier_group(int *event_notifier_group_fd)
241 {
242 int ret;
243 int local_fd = -1;
244
245 assert(event_notifier_group_fd);
246
247 /* Kernel event notifier group creation. */
248 ret = kernctl_create_event_notifier_group(kernel_tracer_fd);
249 if (ret < 0) {
250 PERROR("Failed to create kernel event notifier group");
251 ret = -1;
252 goto error;
253 }
254
255 local_fd = ret;
256
257 /* Prevent fd duplication after execlp(). */
258 ret = fcntl(local_fd, F_SETFD, FD_CLOEXEC);
259 if (ret < 0) {
260 PERROR("Failed to set FD_CLOEXEC on kernel event notifier group file descriptor: fd = %d",
261 local_fd);
262 goto error;
263 }
264
265 DBG("Created kernel event notifier group: fd = %d", local_fd);
266 *event_notifier_group_fd = local_fd;
267 local_fd = -1;
268 ret = 0;
269 error:
270 if (local_fd >= 0) {
271 ret = close(local_fd);
272 if (ret) {
273 PERROR("Failed to close kernel event notifier group file descriptor: fd = %d",
274 local_fd);
275 }
276 }
277
278 return ret;
279 }
280
281 /*
282 * Compute the offset of the instrumentation byte in the binary based on the
283 * function probe location using the ELF lookup method.
284 *
285 * Returns 0 on success and set the offset out parameter to the offset of the
286 * elf symbol
287 * Returns -1 on error
288 */
289 static
290 int extract_userspace_probe_offset_function_elf(
291 const struct lttng_userspace_probe_location *probe_location,
292 uid_t uid, gid_t gid, uint64_t *offset)
293 {
294 int fd;
295 int ret = 0;
296 const char *symbol = NULL;
297 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
298 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type;
299
300 assert(lttng_userspace_probe_location_get_type(probe_location) ==
301 LTTNG_USERSPACE_PROBE_LOCATION_TYPE_FUNCTION);
302
303 lookup = lttng_userspace_probe_location_get_lookup_method(
304 probe_location);
305 if (!lookup) {
306 ret = -1;
307 goto end;
308 }
309
310 lookup_method_type =
311 lttng_userspace_probe_location_lookup_method_get_type(lookup);
312
313 assert(lookup_method_type ==
314 LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF);
315
316 symbol = lttng_userspace_probe_location_function_get_function_name(
317 probe_location);
318 if (!symbol) {
319 ret = -1;
320 goto end;
321 }
322
323 fd = lttng_userspace_probe_location_function_get_binary_fd(probe_location);
324 if (fd < 0) {
325 ret = -1;
326 goto end;
327 }
328
329 ret = run_as_extract_elf_symbol_offset(fd, symbol, uid, gid, offset);
330 if (ret < 0) {
331 DBG("userspace probe offset calculation failed for "
332 "function %s", symbol);
333 goto end;
334 }
335
336 DBG("userspace probe elf offset for %s is 0x%jd", symbol, (intmax_t)(*offset));
337 end:
338 return ret;
339 }
340
341 /*
342 * Compute the offsets of the instrumentation bytes in the binary based on the
343 * tracepoint probe location using the SDT lookup method. This function
344 * allocates the offsets buffer, the caller must free it.
345 *
346 * Returns 0 on success and set the offset out parameter to the offsets of the
347 * SDT tracepoint.
348 * Returns -1 on error.
349 */
350 static
351 int extract_userspace_probe_offset_tracepoint_sdt(
352 const struct lttng_userspace_probe_location *probe_location,
353 uid_t uid, gid_t gid, uint64_t **offsets,
354 uint32_t *offsets_count)
355 {
356 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type;
357 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
358 const char *probe_name = NULL, *provider_name = NULL;
359 int ret = 0;
360 int fd, i;
361
362 assert(lttng_userspace_probe_location_get_type(probe_location) ==
363 LTTNG_USERSPACE_PROBE_LOCATION_TYPE_TRACEPOINT);
364
365 lookup = lttng_userspace_probe_location_get_lookup_method(probe_location);
366 if (!lookup) {
367 ret = -1;
368 goto end;
369 }
370
371 lookup_method_type =
372 lttng_userspace_probe_location_lookup_method_get_type(lookup);
373
374 assert(lookup_method_type ==
375 LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT);
376
377
378 probe_name = lttng_userspace_probe_location_tracepoint_get_probe_name(
379 probe_location);
380 if (!probe_name) {
381 ret = -1;
382 goto end;
383 }
384
385 provider_name = lttng_userspace_probe_location_tracepoint_get_provider_name(
386 probe_location);
387 if (!provider_name) {
388 ret = -1;
389 goto end;
390 }
391
392 fd = lttng_userspace_probe_location_tracepoint_get_binary_fd(probe_location);
393 if (fd < 0) {
394 ret = -1;
395 goto end;
396 }
397
398 ret = run_as_extract_sdt_probe_offsets(fd, provider_name, probe_name,
399 uid, gid, offsets, offsets_count);
400 if (ret < 0) {
401 DBG("userspace probe offset calculation failed for sdt "
402 "probe %s:%s", provider_name, probe_name);
403 goto end;
404 }
405
406 if (*offsets_count == 0) {
407 DBG("no userspace probe offset found");
408 goto end;
409 }
410
411 DBG("%u userspace probe SDT offsets found for %s:%s at:",
412 *offsets_count, provider_name, probe_name);
413 for (i = 0; i < *offsets_count; i++) {
414 DBG("\t0x%jd", (intmax_t)((*offsets)[i]));
415 }
416 end:
417 return ret;
418 }
419
420 static
421 int userspace_probe_add_callsite(
422 const struct lttng_userspace_probe_location *location,
423 uid_t uid, gid_t gid, int fd)
424 {
425 const struct lttng_userspace_probe_location_lookup_method *lookup_method = NULL;
426 enum lttng_userspace_probe_location_lookup_method_type type;
427 int ret;
428
429 lookup_method = lttng_userspace_probe_location_get_lookup_method(location);
430 if (!lookup_method) {
431 ret = -1;
432 goto end;
433 }
434
435 type = lttng_userspace_probe_location_lookup_method_get_type(lookup_method);
436 switch (type) {
437 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
438 {
439 struct lttng_kernel_event_callsite callsite;
440 uint64_t offset;
441
442 ret = extract_userspace_probe_offset_function_elf(location,
443 uid, gid, &offset);
444 if (ret) {
445 ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
446 goto end;
447 }
448
449 callsite.u.uprobe.offset = offset;
450 ret = kernctl_add_callsite(fd, &callsite);
451 if (ret) {
452 WARN("Failed to add callsite to ELF userspace probe.");
453 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
454 goto end;
455 }
456 break;
457 }
458 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
459 {
460 int i;
461 uint64_t *offsets = NULL;
462 uint32_t offsets_count;
463 struct lttng_kernel_event_callsite callsite;
464
465 /*
466 * This call allocates the offsets buffer. This buffer must be freed
467 * by the caller
468 */
469 ret = extract_userspace_probe_offset_tracepoint_sdt(location,
470 uid, gid, &offsets, &offsets_count);
471 if (ret) {
472 ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
473 goto end;
474 }
475 for (i = 0; i < offsets_count; i++) {
476 callsite.u.uprobe.offset = offsets[i];
477 ret = kernctl_add_callsite(fd, &callsite);
478 if (ret) {
479 WARN("Failed to add callsite to SDT userspace probe");
480 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
481 free(offsets);
482 goto end;
483 }
484 }
485 free(offsets);
486 break;
487 }
488 default:
489 ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
490 goto end;
491 }
492 end:
493 return ret;
494 }
495
496 /*
497 * Extract the offsets of the instrumentation point for the different lookup
498 * methods.
499 */
500 static
501 int userspace_probe_event_add_callsites(struct lttng_event *ev,
502 struct ltt_kernel_session *session, int fd)
503 {
504 int ret;
505 const struct lttng_userspace_probe_location *location = NULL;
506
507 assert(ev);
508 assert(ev->type == LTTNG_EVENT_USERSPACE_PROBE);
509
510 location = lttng_event_get_userspace_probe_location(ev);
511 if (!location) {
512 ret = -1;
513 goto end;
514 }
515
516 ret = userspace_probe_add_callsite(location, session->uid, session->gid,
517 fd);
518 if (ret) {
519 WARN("Failed to add callsite to userspace probe event '%s'",
520 ev->name);
521 }
522
523 end:
524 return ret;
525 }
526
527 /*
528 * Extract the offsets of the instrumentation point for the different look-up
529 * methods.
530 */
531 static int userspace_probe_event_rule_add_callsites(
532 const struct lttng_event_rule *rule,
533 const struct lttng_credentials *creds,
534 int fd)
535 {
536 int ret;
537 enum lttng_event_rule_status status;
538 enum lttng_event_rule_type event_rule_type;
539 const struct lttng_userspace_probe_location *location = NULL;
540
541 assert(rule);
542 assert(creds);
543
544 event_rule_type = lttng_event_rule_get_type(rule);
545 assert(event_rule_type == LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE);
546
547 status = lttng_event_rule_userspace_probe_get_location(rule, &location);
548 if (status != LTTNG_EVENT_RULE_STATUS_OK || !location) {
549 ret = -1;
550 goto end;
551 }
552
553 ret = userspace_probe_add_callsite(location,
554 lttng_credentials_get_uid(creds),
555 lttng_credentials_get_gid(creds), fd);
556 if (ret) {
557 WARN("Failed to add callsite to user space probe object: fd = %d",
558 fd);
559 }
560
561 end:
562 return ret;
563 }
564
565 /*
566 * Create a kernel event, enable it to the kernel tracer and add it to the
567 * channel event list of the kernel session.
568 * We own filter_expression and filter.
569 */
570 int kernel_create_event(struct lttng_event *ev,
571 struct ltt_kernel_channel *channel,
572 char *filter_expression,
573 struct lttng_bytecode *filter)
574 {
575 int err, fd;
576 enum lttng_error_code ret;
577 struct ltt_kernel_event *event;
578
579 assert(ev);
580 assert(channel);
581
582 /* We pass ownership of filter_expression and filter */
583 ret = trace_kernel_create_event(ev, filter_expression,
584 filter, &event);
585 if (ret != LTTNG_OK) {
586 goto error;
587 }
588
589 fd = kernctl_create_event(channel->fd, event->event);
590 if (fd < 0) {
591 switch (-fd) {
592 case EEXIST:
593 ret = LTTNG_ERR_KERN_EVENT_EXIST;
594 break;
595 case ENOSYS:
596 WARN("Event type not implemented");
597 ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
598 break;
599 case ENOENT:
600 WARN("Event %s not found!", ev->name);
601 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
602 break;
603 default:
604 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
605 PERROR("create event ioctl");
606 }
607 goto free_event;
608 }
609
610 event->type = ev->type;
611 event->fd = fd;
612 /* Prevent fd duplication after execlp() */
613 err = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
614 if (err < 0) {
615 PERROR("fcntl session fd");
616 }
617
618 if (filter) {
619 err = kernctl_filter(event->fd, filter);
620 if (err < 0) {
621 switch (-err) {
622 case ENOMEM:
623 ret = LTTNG_ERR_FILTER_NOMEM;
624 break;
625 default:
626 ret = LTTNG_ERR_FILTER_INVAL;
627 break;
628 }
629 goto filter_error;
630 }
631 }
632
633 if (ev->type == LTTNG_EVENT_USERSPACE_PROBE) {
634 ret = userspace_probe_event_add_callsites(ev, channel->session,
635 event->fd);
636 if (ret) {
637 goto add_callsite_error;
638 }
639 }
640
641 err = kernctl_enable(event->fd);
642 if (err < 0) {
643 switch (-err) {
644 case EEXIST:
645 ret = LTTNG_ERR_KERN_EVENT_EXIST;
646 break;
647 default:
648 PERROR("enable kernel event");
649 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
650 break;
651 }
652 goto enable_error;
653 }
654
655 /* Add event to event list */
656 cds_list_add(&event->list, &channel->events_list.head);
657 channel->event_count++;
658
659 DBG("Event %s created (fd: %d)", ev->name, event->fd);
660
661 return 0;
662
663 add_callsite_error:
664 enable_error:
665 filter_error:
666 {
667 int closeret;
668
669 closeret = close(event->fd);
670 if (closeret) {
671 PERROR("close event fd");
672 }
673 }
674 free_event:
675 free(event);
676 error:
677 return ret;
678 }
679
680 /*
681 * Disable a kernel channel.
682 */
683 int kernel_disable_channel(struct ltt_kernel_channel *chan)
684 {
685 int ret;
686
687 assert(chan);
688
689 ret = kernctl_disable(chan->fd);
690 if (ret < 0) {
691 PERROR("disable chan ioctl");
692 goto error;
693 }
694
695 chan->enabled = 0;
696 DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64 ")",
697 chan->channel->name, chan->fd, chan->key);
698
699 return 0;
700
701 error:
702 return ret;
703 }
704
705 /*
706 * Enable a kernel channel.
707 */
708 int kernel_enable_channel(struct ltt_kernel_channel *chan)
709 {
710 int ret;
711
712 assert(chan);
713
714 ret = kernctl_enable(chan->fd);
715 if (ret < 0 && ret != -EEXIST) {
716 PERROR("Enable kernel chan");
717 goto error;
718 }
719
720 chan->enabled = 1;
721 DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64 ")",
722 chan->channel->name, chan->fd, chan->key);
723
724 return 0;
725
726 error:
727 return ret;
728 }
729
730 /*
731 * Enable a kernel event.
732 */
733 int kernel_enable_event(struct ltt_kernel_event *event)
734 {
735 int ret;
736
737 assert(event);
738
739 ret = kernctl_enable(event->fd);
740 if (ret < 0) {
741 switch (-ret) {
742 case EEXIST:
743 ret = LTTNG_ERR_KERN_EVENT_EXIST;
744 break;
745 default:
746 PERROR("enable kernel event");
747 break;
748 }
749 goto error;
750 }
751
752 event->enabled = 1;
753 DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
754
755 return 0;
756
757 error:
758 return ret;
759 }
760
761 /*
762 * Disable a kernel event.
763 */
764 int kernel_disable_event(struct ltt_kernel_event *event)
765 {
766 int ret;
767
768 assert(event);
769
770 ret = kernctl_disable(event->fd);
771 if (ret < 0) {
772 PERROR("Failed to disable kernel event: name = '%s', fd = %d",
773 event->event->name, event->fd);
774 goto error;
775 }
776
777 event->enabled = 0;
778 DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
779
780 return 0;
781
782 error:
783 return ret;
784 }
785
786 /*
787 * Disable a kernel event notifier.
788 */
789 static
790 int kernel_disable_event_notifier_rule(struct ltt_kernel_event_notifier_rule *event)
791 {
792 int ret;
793
794 assert(event);
795
796 rcu_read_lock();
797 cds_lfht_del(kernel_token_to_event_notifier_rule_ht, &event->ht_node);
798 rcu_read_unlock();
799
800 ret = kernctl_disable(event->fd);
801 if (ret < 0) {
802 PERROR("Failed to disable kernel event notifier: fd = %d, token = %" PRIu64,
803 event->fd, event->token);
804 goto error;
805 }
806
807 event->enabled = 0;
808 DBG("Disabled kernel event notifier: fd = %d, token = %" PRIu64,
809 event->fd, event->token);
810
811 error:
812 return ret;
813 }
814
815 static
816 struct process_attr_tracker *_kernel_get_process_attr_tracker(
817 struct ltt_kernel_session *session,
818 enum lttng_process_attr process_attr)
819 {
820 switch (process_attr) {
821 case LTTNG_PROCESS_ATTR_PROCESS_ID:
822 return session->tracker_pid;
823 case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
824 return session->tracker_vpid;
825 case LTTNG_PROCESS_ATTR_USER_ID:
826 return session->tracker_uid;
827 case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
828 return session->tracker_vuid;
829 case LTTNG_PROCESS_ATTR_GROUP_ID:
830 return session->tracker_gid;
831 case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
832 return session->tracker_vgid;
833 default:
834 return NULL;
835 }
836 }
837
838 const struct process_attr_tracker *kernel_get_process_attr_tracker(
839 struct ltt_kernel_session *session,
840 enum lttng_process_attr process_attr)
841 {
842 return (const struct process_attr_tracker *)
843 _kernel_get_process_attr_tracker(session, process_attr);
844 }
845
846 enum lttng_error_code kernel_process_attr_tracker_set_tracking_policy(
847 struct ltt_kernel_session *session,
848 enum lttng_process_attr process_attr,
849 enum lttng_tracking_policy policy)
850 {
851 int ret;
852 enum lttng_error_code ret_code = LTTNG_OK;
853 struct process_attr_tracker *tracker =
854 _kernel_get_process_attr_tracker(session, process_attr);
855 enum lttng_tracking_policy previous_policy;
856
857 if (!tracker) {
858 ret_code = LTTNG_ERR_INVALID;
859 goto end;
860 }
861
862 previous_policy = process_attr_tracker_get_tracking_policy(tracker);
863 ret = process_attr_tracker_set_tracking_policy(tracker, policy);
864 if (ret) {
865 ret_code = LTTNG_ERR_UNK;
866 goto end;
867 }
868
869 if (previous_policy == policy) {
870 goto end;
871 }
872
873 switch (policy) {
874 case LTTNG_TRACKING_POLICY_INCLUDE_ALL:
875 if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
876 /*
877 * Maintain a special case for the process ID process
878 * attribute tracker as it was the only supported
879 * attribute prior to 2.12.
880 */
881 ret = kernctl_track_pid(session->fd, -1);
882 } else {
883 ret = kernctl_track_id(session->fd, process_attr, -1);
884 }
885 break;
886 case LTTNG_TRACKING_POLICY_EXCLUDE_ALL:
887 case LTTNG_TRACKING_POLICY_INCLUDE_SET:
888 /* fall-through. */
889 if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
890 /*
891 * Maintain a special case for the process ID process
892 * attribute tracker as it was the only supported
893 * attribute prior to 2.12.
894 */
895 ret = kernctl_untrack_pid(session->fd, -1);
896 } else {
897 ret = kernctl_untrack_id(session->fd, process_attr, -1);
898 }
899 break;
900 default:
901 abort();
902 }
903 /* kern-ctl error handling */
904 switch (-ret) {
905 case 0:
906 ret_code = LTTNG_OK;
907 break;
908 case EINVAL:
909 ret_code = LTTNG_ERR_INVALID;
910 break;
911 case ENOMEM:
912 ret_code = LTTNG_ERR_NOMEM;
913 break;
914 case EEXIST:
915 ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
916 break;
917 default:
918 ret_code = LTTNG_ERR_UNK;
919 break;
920 }
921 end:
922 return ret_code;
923 }
924
925 enum lttng_error_code kernel_process_attr_tracker_inclusion_set_add_value(
926 struct ltt_kernel_session *session,
927 enum lttng_process_attr process_attr,
928 const struct process_attr_value *value)
929 {
930 int ret, integral_value;
931 enum lttng_error_code ret_code;
932 struct process_attr_tracker *tracker;
933 enum process_attr_tracker_status status;
934
935 /*
936 * Convert process attribute tracker value to the integral
937 * representation required by the kern-ctl API.
938 */
939 switch (process_attr) {
940 case LTTNG_PROCESS_ATTR_PROCESS_ID:
941 case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
942 integral_value = (int) value->value.pid;
943 break;
944 case LTTNG_PROCESS_ATTR_USER_ID:
945 case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
946 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
947 uid_t uid;
948
949 ret_code = utils_user_id_from_name(
950 value->value.user_name, &uid);
951 if (ret_code != LTTNG_OK) {
952 goto end;
953 }
954 integral_value = (int) uid;
955 } else {
956 integral_value = (int) value->value.uid;
957 }
958 break;
959 case LTTNG_PROCESS_ATTR_GROUP_ID:
960 case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
961 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
962 gid_t gid;
963
964 ret_code = utils_group_id_from_name(
965 value->value.group_name, &gid);
966 if (ret_code != LTTNG_OK) {
967 goto end;
968 }
969 integral_value = (int) gid;
970 } else {
971 integral_value = (int) value->value.gid;
972 }
973 break;
974 default:
975 ret_code = LTTNG_ERR_INVALID;
976 goto end;
977 }
978
979 tracker = _kernel_get_process_attr_tracker(session, process_attr);
980 if (!tracker) {
981 ret_code = LTTNG_ERR_INVALID;
982 goto end;
983 }
984
985 status = process_attr_tracker_inclusion_set_add_value(tracker, value);
986 if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
987 switch (status) {
988 case PROCESS_ATTR_TRACKER_STATUS_EXISTS:
989 ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
990 break;
991 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
992 ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
993 break;
994 case PROCESS_ATTR_TRACKER_STATUS_ERROR:
995 default:
996 ret_code = LTTNG_ERR_UNK;
997 break;
998 }
999 goto end;
1000 }
1001
1002 DBG("Kernel track %s %d for session id %" PRIu64,
1003 lttng_process_attr_to_string(process_attr),
1004 integral_value, session->id);
1005 if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
1006 /*
1007 * Maintain a special case for the process ID process attribute
1008 * tracker as it was the only supported attribute prior to 2.12.
1009 */
1010 ret = kernctl_track_pid(session->fd, integral_value);
1011 } else {
1012 ret = kernctl_track_id(
1013 session->fd, process_attr, integral_value);
1014 }
1015 if (ret == 0) {
1016 ret_code = LTTNG_OK;
1017 goto end;
1018 }
1019
1020 kernel_wait_quiescent();
1021
1022 /* kern-ctl error handling */
1023 switch (-ret) {
1024 case 0:
1025 ret_code = LTTNG_OK;
1026 break;
1027 case EINVAL:
1028 ret_code = LTTNG_ERR_INVALID;
1029 break;
1030 case ENOMEM:
1031 ret_code = LTTNG_ERR_NOMEM;
1032 break;
1033 case EEXIST:
1034 ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
1035 break;
1036 default:
1037 ret_code = LTTNG_ERR_UNK;
1038 break;
1039 }
1040
1041 /* Attempt to remove the value from the tracker. */
1042 status = process_attr_tracker_inclusion_set_remove_value(
1043 tracker, value);
1044 if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1045 ERR("Failed to roll-back the tracking of kernel %s process attribute %d while handling a kern-ctl error",
1046 lttng_process_attr_to_string(process_attr),
1047 integral_value);
1048 }
1049 end:
1050 return ret_code;
1051 }
1052
1053 enum lttng_error_code kernel_process_attr_tracker_inclusion_set_remove_value(
1054 struct ltt_kernel_session *session,
1055 enum lttng_process_attr process_attr,
1056 const struct process_attr_value *value)
1057 {
1058 int ret, integral_value;
1059 enum lttng_error_code ret_code;
1060 struct process_attr_tracker *tracker;
1061 enum process_attr_tracker_status status;
1062
1063 /*
1064 * Convert process attribute tracker value to the integral
1065 * representation required by the kern-ctl API.
1066 */
1067 switch (process_attr) {
1068 case LTTNG_PROCESS_ATTR_PROCESS_ID:
1069 case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1070 integral_value = (int) value->value.pid;
1071 break;
1072 case LTTNG_PROCESS_ATTR_USER_ID:
1073 case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
1074 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
1075 uid_t uid;
1076
1077 ret_code = utils_user_id_from_name(
1078 value->value.user_name, &uid);
1079 if (ret_code != LTTNG_OK) {
1080 goto end;
1081 }
1082 integral_value = (int) uid;
1083 } else {
1084 integral_value = (int) value->value.uid;
1085 }
1086 break;
1087 case LTTNG_PROCESS_ATTR_GROUP_ID:
1088 case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
1089 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
1090 gid_t gid;
1091
1092 ret_code = utils_group_id_from_name(
1093 value->value.group_name, &gid);
1094 if (ret_code != LTTNG_OK) {
1095 goto end;
1096 }
1097 integral_value = (int) gid;
1098 } else {
1099 integral_value = (int) value->value.gid;
1100 }
1101 break;
1102 default:
1103 ret_code = LTTNG_ERR_INVALID;
1104 goto end;
1105 }
1106
1107 tracker = _kernel_get_process_attr_tracker(session, process_attr);
1108 if (!tracker) {
1109 ret_code = LTTNG_ERR_INVALID;
1110 goto end;
1111 }
1112
1113 status = process_attr_tracker_inclusion_set_remove_value(
1114 tracker, value);
1115 if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1116 switch (status) {
1117 case PROCESS_ATTR_TRACKER_STATUS_MISSING:
1118 ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
1119 break;
1120 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
1121 ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
1122 break;
1123 case PROCESS_ATTR_TRACKER_STATUS_ERROR:
1124 default:
1125 ret_code = LTTNG_ERR_UNK;
1126 break;
1127 }
1128 goto end;
1129 }
1130
1131 DBG("Kernel track %s %d for session id %" PRIu64,
1132 lttng_process_attr_to_string(process_attr),
1133 integral_value, session->id);
1134 if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
1135 /*
1136 * Maintain a special case for the process ID process attribute
1137 * tracker as it was the only supported attribute prior to 2.12.
1138 */
1139 ret = kernctl_untrack_pid(session->fd, integral_value);
1140 } else {
1141 ret = kernctl_untrack_id(
1142 session->fd, process_attr, integral_value);
1143 }
1144 if (ret == 0) {
1145 ret_code = LTTNG_OK;
1146 goto end;
1147 }
1148 kernel_wait_quiescent();
1149
1150 /* kern-ctl error handling */
1151 switch (-ret) {
1152 case 0:
1153 ret_code = LTTNG_OK;
1154 break;
1155 case EINVAL:
1156 ret_code = LTTNG_ERR_INVALID;
1157 break;
1158 case ENOMEM:
1159 ret_code = LTTNG_ERR_NOMEM;
1160 break;
1161 case ENOENT:
1162 ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
1163 break;
1164 default:
1165 ret_code = LTTNG_ERR_UNK;
1166 break;
1167 }
1168
1169 /* Attempt to add the value to the tracker. */
1170 status = process_attr_tracker_inclusion_set_add_value(
1171 tracker, value);
1172 if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1173 ERR("Failed to roll-back the tracking of kernel %s process attribute %d while handling a kern-ctl error",
1174 lttng_process_attr_to_string(process_attr),
1175 integral_value);
1176 }
1177 end:
1178 return ret_code;
1179 }
1180
1181 /*
1182 * Create kernel metadata, open from the kernel tracer and add it to the
1183 * kernel session.
1184 */
1185 int kernel_open_metadata(struct ltt_kernel_session *session)
1186 {
1187 int ret;
1188 struct ltt_kernel_metadata *lkm = NULL;
1189
1190 assert(session);
1191
1192 /* Allocate kernel metadata */
1193 lkm = trace_kernel_create_metadata();
1194 if (lkm == NULL) {
1195 goto error;
1196 }
1197
1198 /* Kernel tracer metadata creation */
1199 ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
1200 if (ret < 0) {
1201 goto error_open;
1202 }
1203
1204 lkm->fd = ret;
1205 lkm->key = ++next_kernel_channel_key;
1206 /* Prevent fd duplication after execlp() */
1207 ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
1208 if (ret < 0) {
1209 PERROR("fcntl session fd");
1210 }
1211
1212 session->metadata = lkm;
1213
1214 DBG("Kernel metadata opened (fd: %d)", lkm->fd);
1215
1216 return 0;
1217
1218 error_open:
1219 trace_kernel_destroy_metadata(lkm);
1220 error:
1221 return -1;
1222 }
1223
1224 /*
1225 * Start tracing session.
1226 */
1227 int kernel_start_session(struct ltt_kernel_session *session)
1228 {
1229 int ret;
1230
1231 assert(session);
1232
1233 ret = kernctl_start_session(session->fd);
1234 if (ret < 0) {
1235 PERROR("ioctl start session");
1236 goto error;
1237 }
1238
1239 DBG("Kernel session started");
1240
1241 return 0;
1242
1243 error:
1244 return ret;
1245 }
1246
1247 /*
1248 * Make a kernel wait to make sure in-flight probe have completed.
1249 */
1250 void kernel_wait_quiescent(void)
1251 {
1252 int ret;
1253 int fd = kernel_tracer_fd;
1254
1255 DBG("Kernel quiescent wait on %d", fd);
1256
1257 ret = kernctl_wait_quiescent(fd);
1258 if (ret < 0) {
1259 PERROR("wait quiescent ioctl");
1260 ERR("Kernel quiescent wait failed");
1261 }
1262 }
1263
1264 /*
1265 * Force flush buffer of metadata.
1266 */
1267 int kernel_metadata_flush_buffer(int fd)
1268 {
1269 int ret;
1270
1271 DBG("Kernel flushing metadata buffer on fd %d", fd);
1272
1273 ret = kernctl_buffer_flush(fd);
1274 if (ret < 0) {
1275 ERR("Fail to flush metadata buffers %d (ret: %d)", fd, ret);
1276 }
1277
1278 return 0;
1279 }
1280
1281 /*
1282 * Force flush buffer for channel.
1283 */
1284 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
1285 {
1286 int ret;
1287 struct ltt_kernel_stream *stream;
1288
1289 assert(channel);
1290
1291 DBG("Flush buffer for channel %s", channel->channel->name);
1292
1293 cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
1294 DBG("Flushing channel stream %d", stream->fd);
1295 ret = kernctl_buffer_flush(stream->fd);
1296 if (ret < 0) {
1297 PERROR("ioctl");
1298 ERR("Fail to flush buffer for stream %d (ret: %d)",
1299 stream->fd, ret);
1300 }
1301 }
1302
1303 return 0;
1304 }
1305
1306 /*
1307 * Stop tracing session.
1308 */
1309 int kernel_stop_session(struct ltt_kernel_session *session)
1310 {
1311 int ret;
1312
1313 assert(session);
1314
1315 ret = kernctl_stop_session(session->fd);
1316 if (ret < 0) {
1317 goto error;
1318 }
1319
1320 DBG("Kernel session stopped");
1321
1322 return 0;
1323
1324 error:
1325 return ret;
1326 }
1327
1328 /*
1329 * Open stream of channel, register it to the kernel tracer and add it
1330 * to the stream list of the channel.
1331 *
1332 * Note: given that the streams may appear in random order wrt CPU
1333 * number (e.g. cpu hotplug), the index value of the stream number in
1334 * the stream name is not necessarily linked to the CPU number.
1335 *
1336 * Return the number of created stream. Else, a negative value.
1337 */
1338 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
1339 {
1340 int ret;
1341 struct ltt_kernel_stream *lks;
1342
1343 assert(channel);
1344
1345 while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
1346 lks = trace_kernel_create_stream(channel->channel->name,
1347 channel->stream_count);
1348 if (lks == NULL) {
1349 ret = close(ret);
1350 if (ret) {
1351 PERROR("close");
1352 }
1353 goto error;
1354 }
1355
1356 lks->fd = ret;
1357 /* Prevent fd duplication after execlp() */
1358 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
1359 if (ret < 0) {
1360 PERROR("fcntl session fd");
1361 }
1362
1363 lks->tracefile_size = channel->channel->attr.tracefile_size;
1364 lks->tracefile_count = channel->channel->attr.tracefile_count;
1365
1366 /* Add stream to channel stream list */
1367 cds_list_add(&lks->list, &channel->stream_list.head);
1368 channel->stream_count++;
1369
1370 DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd,
1371 lks->state);
1372 }
1373
1374 return channel->stream_count;
1375
1376 error:
1377 return -1;
1378 }
1379
1380 /*
1381 * Open the metadata stream and set it to the kernel session.
1382 */
1383 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
1384 {
1385 int ret;
1386
1387 assert(session);
1388
1389 ret = kernctl_create_stream(session->metadata->fd);
1390 if (ret < 0) {
1391 PERROR("kernel create metadata stream");
1392 goto error;
1393 }
1394
1395 DBG("Kernel metadata stream created (fd: %d)", ret);
1396 session->metadata_stream_fd = ret;
1397 /* Prevent fd duplication after execlp() */
1398 ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
1399 if (ret < 0) {
1400 PERROR("fcntl session fd");
1401 }
1402
1403 return 0;
1404
1405 error:
1406 return -1;
1407 }
1408
1409 /*
1410 * Get the event list from the kernel tracer and return the number of elements.
1411 */
1412 ssize_t kernel_list_events(struct lttng_event **events)
1413 {
1414 int fd, ret;
1415 char *event;
1416 size_t nbmem, count = 0;
1417 FILE *fp;
1418 struct lttng_event *elist;
1419
1420 assert(events);
1421
1422 fd = kernctl_tracepoint_list(kernel_tracer_fd);
1423 if (fd < 0) {
1424 PERROR("kernel tracepoint list");
1425 goto error;
1426 }
1427
1428 fp = fdopen(fd, "r");
1429 if (fp == NULL) {
1430 PERROR("kernel tracepoint list fdopen");
1431 goto error_fp;
1432 }
1433
1434 /*
1435 * Init memory size counter
1436 * See kernel-ctl.h for explanation of this value
1437 */
1438 nbmem = KERNEL_EVENT_INIT_LIST_SIZE;
1439 elist = zmalloc(sizeof(struct lttng_event) * nbmem);
1440 if (elist == NULL) {
1441 PERROR("alloc list events");
1442 count = -ENOMEM;
1443 goto end;
1444 }
1445
1446 while (fscanf(fp, "event { name = %m[^;]; };\n", &event) == 1) {
1447 if (count >= nbmem) {
1448 struct lttng_event *new_elist;
1449 size_t new_nbmem;
1450
1451 new_nbmem = nbmem << 1;
1452 DBG("Reallocating event list from %zu to %zu bytes",
1453 nbmem, new_nbmem);
1454 new_elist = realloc(elist, new_nbmem * sizeof(struct lttng_event));
1455 if (new_elist == NULL) {
1456 PERROR("realloc list events");
1457 free(event);
1458 free(elist);
1459 count = -ENOMEM;
1460 goto end;
1461 }
1462 /* Zero the new memory */
1463 memset(new_elist + nbmem, 0,
1464 (new_nbmem - nbmem) * sizeof(struct lttng_event));
1465 nbmem = new_nbmem;
1466 elist = new_elist;
1467 }
1468 strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
1469 elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
1470 elist[count].enabled = -1;
1471 count++;
1472 free(event);
1473 }
1474
1475 *events = elist;
1476 DBG("Kernel list events done (%zu events)", count);
1477 end:
1478 ret = fclose(fp); /* closes both fp and fd */
1479 if (ret) {
1480 PERROR("fclose");
1481 }
1482 return count;
1483
1484 error_fp:
1485 ret = close(fd);
1486 if (ret) {
1487 PERROR("close");
1488 }
1489 error:
1490 return -1;
1491 }
1492
1493 /*
1494 * Get kernel version and validate it.
1495 */
1496 int kernel_validate_version(struct lttng_kernel_tracer_version *version,
1497 struct lttng_kernel_tracer_abi_version *abi_version)
1498 {
1499 int ret;
1500
1501 ret = kernctl_tracer_version(kernel_tracer_fd, version);
1502 if (ret < 0) {
1503 ERR("Failed to retrieve the lttng-modules version");
1504 goto error;
1505 }
1506
1507 /* Validate version */
1508 if (version->major != VERSION_MAJOR) {
1509 ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
1510 version->major, VERSION_MAJOR);
1511 goto error_version;
1512 }
1513 ret = kernctl_tracer_abi_version(kernel_tracer_fd, abi_version);
1514 if (ret < 0) {
1515 ERR("Failed to retrieve lttng-modules ABI version");
1516 goto error;
1517 }
1518 if (abi_version->major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
1519 ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
1520 abi_version->major, abi_version->minor,
1521 LTTNG_MODULES_ABI_MAJOR_VERSION);
1522 goto error;
1523 }
1524 DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
1525 version->major, version->minor,
1526 abi_version->major, abi_version->minor);
1527 return 0;
1528
1529 error_version:
1530 ret = -1;
1531
1532 error:
1533 ERR("Kernel tracer version check failed; kernel tracing will not be available");
1534 return ret;
1535 }
1536
1537 /*
1538 * Kernel work-arounds called at the start of sessiond main().
1539 */
1540 int init_kernel_workarounds(void)
1541 {
1542 int ret;
1543 FILE *fp;
1544
1545 /*
1546 * boot_id needs to be read once before being used concurrently
1547 * to deal with a Linux kernel race. A fix is proposed for
1548 * upstream, but the work-around is needed for older kernels.
1549 */
1550 fp = fopen("/proc/sys/kernel/random/boot_id", "r");
1551 if (!fp) {
1552 goto end_boot_id;
1553 }
1554 while (!feof(fp)) {
1555 char buf[37] = "";
1556
1557 ret = fread(buf, 1, sizeof(buf), fp);
1558 if (ret < 0) {
1559 /* Ignore error, we don't really care */
1560 }
1561 }
1562 ret = fclose(fp);
1563 if (ret) {
1564 PERROR("fclose");
1565 }
1566 end_boot_id:
1567 return 0;
1568 }
1569
1570 /*
1571 * Teardown of a kernel session, keeping data required by destroy notifiers.
1572 */
1573 void kernel_destroy_session(struct ltt_kernel_session *ksess)
1574 {
1575 struct lttng_trace_chunk *trace_chunk;
1576
1577 if (ksess == NULL) {
1578 DBG3("No kernel session when tearing down session");
1579 return;
1580 }
1581
1582 DBG("Tearing down kernel session");
1583 trace_chunk = ksess->current_trace_chunk;
1584
1585 /*
1586 * Destroy channels on the consumer if at least one FD has been sent and we
1587 * are in no output mode because the streams are in *no* monitor mode so we
1588 * have to send a command to clean them up or else they leaked.
1589 */
1590 if (!ksess->output_traces && ksess->consumer_fds_sent) {
1591 int ret;
1592 struct consumer_socket *socket;
1593 struct lttng_ht_iter iter;
1594
1595 /* For each consumer socket. */
1596 rcu_read_lock();
1597 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
1598 socket, node.node) {
1599 struct ltt_kernel_channel *chan;
1600
1601 /* For each channel, ask the consumer to destroy it. */
1602 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
1603 ret = kernel_consumer_destroy_channel(socket, chan);
1604 if (ret < 0) {
1605 /* Consumer is probably dead. Use next socket. */
1606 continue;
1607 }
1608 }
1609 }
1610 rcu_read_unlock();
1611 }
1612
1613 /* Close any relayd session */
1614 consumer_output_send_destroy_relayd(ksess->consumer);
1615
1616 trace_kernel_destroy_session(ksess);
1617 lttng_trace_chunk_put(trace_chunk);
1618 }
1619
1620 /* Teardown of data required by destroy notifiers. */
1621 void kernel_free_session(struct ltt_kernel_session *ksess)
1622 {
1623 if (ksess == NULL) {
1624 return;
1625 }
1626 trace_kernel_free_session(ksess);
1627 }
1628
1629 /*
1630 * Destroy a kernel channel object. It does not do anything on the tracer side.
1631 */
1632 void kernel_destroy_channel(struct ltt_kernel_channel *kchan)
1633 {
1634 struct ltt_kernel_session *ksess = NULL;
1635
1636 assert(kchan);
1637 assert(kchan->channel);
1638
1639 DBG3("Kernel destroy channel %s", kchan->channel->name);
1640
1641 /* Update channel count of associated session. */
1642 if (kchan->session) {
1643 /* Keep pointer reference so we can update it after the destroy. */
1644 ksess = kchan->session;
1645 }
1646
1647 trace_kernel_destroy_channel(kchan);
1648
1649 /*
1650 * At this point the kernel channel is not visible anymore. This is safe
1651 * since in order to work on a visible kernel session, the tracing session
1652 * lock (ltt_session.lock) MUST be acquired.
1653 */
1654 if (ksess) {
1655 ksess->channel_count--;
1656 }
1657 }
1658
1659 /*
1660 * Take a snapshot for a given kernel session.
1661 *
1662 * Return LTTNG_OK on success or else return a LTTNG_ERR code.
1663 */
1664 enum lttng_error_code kernel_snapshot_record(
1665 struct ltt_kernel_session *ksess,
1666 const struct consumer_output *output, int wait,
1667 uint64_t nb_packets_per_stream)
1668 {
1669 int err, ret, saved_metadata_fd;
1670 enum lttng_error_code status = LTTNG_OK;
1671 struct consumer_socket *socket;
1672 struct lttng_ht_iter iter;
1673 struct ltt_kernel_metadata *saved_metadata;
1674 char *trace_path = NULL;
1675 size_t consumer_path_offset = 0;
1676
1677 assert(ksess);
1678 assert(ksess->consumer);
1679 assert(output);
1680
1681 DBG("Kernel snapshot record started");
1682
1683 /* Save current metadata since the following calls will change it. */
1684 saved_metadata = ksess->metadata;
1685 saved_metadata_fd = ksess->metadata_stream_fd;
1686
1687 rcu_read_lock();
1688
1689 ret = kernel_open_metadata(ksess);
1690 if (ret < 0) {
1691 status = LTTNG_ERR_KERN_META_FAIL;
1692 goto error;
1693 }
1694
1695 ret = kernel_open_metadata_stream(ksess);
1696 if (ret < 0) {
1697 status = LTTNG_ERR_KERN_META_FAIL;
1698 goto error_open_stream;
1699 }
1700
1701 trace_path = setup_channel_trace_path(ksess->consumer,
1702 DEFAULT_KERNEL_TRACE_DIR, &consumer_path_offset);
1703 if (!trace_path) {
1704 status = LTTNG_ERR_INVALID;
1705 goto error;
1706 }
1707 /* Send metadata to consumer and snapshot everything. */
1708 cds_lfht_for_each_entry(output->socks->ht, &iter.iter,
1709 socket, node.node) {
1710 struct ltt_kernel_channel *chan;
1711
1712 pthread_mutex_lock(socket->lock);
1713 /* This stream must not be monitored by the consumer. */
1714 ret = kernel_consumer_add_metadata(socket, ksess, 0);
1715 pthread_mutex_unlock(socket->lock);
1716 if (ret < 0) {
1717 status = LTTNG_ERR_KERN_META_FAIL;
1718 goto error_consumer;
1719 }
1720
1721 /* For each channel, ask the consumer to snapshot it. */
1722 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
1723 status = consumer_snapshot_channel(socket, chan->key, output, 0,
1724 ksess->uid, ksess->gid,
1725 &trace_path[consumer_path_offset], wait,
1726 nb_packets_per_stream);
1727 if (status != LTTNG_OK) {
1728 (void) kernel_consumer_destroy_metadata(socket,
1729 ksess->metadata);
1730 goto error_consumer;
1731 }
1732 }
1733
1734 /* Snapshot metadata, */
1735 status = consumer_snapshot_channel(socket, ksess->metadata->key, output,
1736 1, ksess->uid, ksess->gid, &trace_path[consumer_path_offset],
1737 wait, 0);
1738 if (status != LTTNG_OK) {
1739 goto error_consumer;
1740 }
1741
1742 /*
1743 * The metadata snapshot is done, ask the consumer to destroy it since
1744 * it's not monitored on the consumer side.
1745 */
1746 (void) kernel_consumer_destroy_metadata(socket, ksess->metadata);
1747 }
1748
1749 error_consumer:
1750 /* Close newly opened metadata stream. It's now on the consumer side. */
1751 err = close(ksess->metadata_stream_fd);
1752 if (err < 0) {
1753 PERROR("close snapshot kernel");
1754 }
1755
1756 error_open_stream:
1757 trace_kernel_destroy_metadata(ksess->metadata);
1758 error:
1759 /* Restore metadata state.*/
1760 ksess->metadata = saved_metadata;
1761 ksess->metadata_stream_fd = saved_metadata_fd;
1762 rcu_read_unlock();
1763 free(trace_path);
1764 return status;
1765 }
1766
1767 /*
1768 * Get the syscall mask array from the kernel tracer.
1769 *
1770 * Return 0 on success else a negative value. In both case, syscall_mask should
1771 * be freed.
1772 */
1773 int kernel_syscall_mask(int chan_fd, char **syscall_mask, uint32_t *nr_bits)
1774 {
1775 assert(syscall_mask);
1776 assert(nr_bits);
1777
1778 return kernctl_syscall_mask(chan_fd, syscall_mask, nr_bits);
1779 }
1780
1781 static
1782 int kernel_tracer_abi_greater_or_equal(unsigned int major, unsigned int minor)
1783 {
1784 int ret;
1785 struct lttng_kernel_tracer_abi_version abi;
1786
1787 ret = kernctl_tracer_abi_version(kernel_tracer_fd, &abi);
1788 if (ret < 0) {
1789 ERR("Failed to retrieve lttng-modules ABI version");
1790 goto error;
1791 }
1792
1793 ret = abi.major > major || (abi.major == major && abi.minor >= minor);
1794 error:
1795 return ret;
1796 }
1797
1798 /*
1799 * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi
1800 * version number.
1801 *
1802 * Return 1 on success, 0 when feature is not supported, negative value in case
1803 * of errors.
1804 */
1805 int kernel_supports_ring_buffer_snapshot_sample_positions(void)
1806 {
1807 /*
1808 * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3
1809 */
1810 return kernel_tracer_abi_greater_or_equal(2, 3);
1811 }
1812
1813 /*
1814 * Check for the support of the packet sequence number via abi version number.
1815 *
1816 * Return 1 on success, 0 when feature is not supported, negative value in case
1817 * of errors.
1818 */
1819 int kernel_supports_ring_buffer_packet_sequence_number(void)
1820 {
1821 /*
1822 * Packet sequence number was introduced in LTTng 2.8,
1823 * lttng-modules ABI 2.1.
1824 */
1825 return kernel_tracer_abi_greater_or_equal(2, 1);
1826 }
1827
1828 /*
1829 * Check for the support of event notifiers via abi version number.
1830 *
1831 * Return 1 on success, 0 when feature is not supported, negative value in case
1832 * of errors.
1833 */
1834 int kernel_supports_event_notifiers(void)
1835 {
1836 /*
1837 * Event notifiers were introduced in LTTng 2.13, lttng-modules ABI 2.6.
1838 */
1839 return kernel_tracer_abi_greater_or_equal(2, 6);
1840 }
1841
1842 /*
1843 * Rotate a kernel session.
1844 *
1845 * Return LTTNG_OK on success or else an LTTng error code.
1846 */
1847 enum lttng_error_code kernel_rotate_session(struct ltt_session *session)
1848 {
1849 int ret;
1850 enum lttng_error_code status = LTTNG_OK;
1851 struct consumer_socket *socket;
1852 struct lttng_ht_iter iter;
1853 struct ltt_kernel_session *ksess = session->kernel_session;
1854
1855 assert(ksess);
1856 assert(ksess->consumer);
1857
1858 DBG("Rotate kernel session %s started (session %" PRIu64 ")",
1859 session->name, session->id);
1860
1861 rcu_read_lock();
1862
1863 /*
1864 * Note that this loop will end after one iteration given that there is
1865 * only one kernel consumer.
1866 */
1867 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
1868 socket, node.node) {
1869 struct ltt_kernel_channel *chan;
1870
1871 /* For each channel, ask the consumer to rotate it. */
1872 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
1873 DBG("Rotate kernel channel %" PRIu64 ", session %s",
1874 chan->key, session->name);
1875 ret = consumer_rotate_channel(socket, chan->key,
1876 ksess->uid, ksess->gid, ksess->consumer,
1877 /* is_metadata_channel */ false);
1878 if (ret < 0) {
1879 status = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
1880 goto error;
1881 }
1882 }
1883
1884 /*
1885 * Rotate the metadata channel.
1886 */
1887 ret = consumer_rotate_channel(socket, ksess->metadata->key,
1888 ksess->uid, ksess->gid, ksess->consumer,
1889 /* is_metadata_channel */ true);
1890 if (ret < 0) {
1891 status = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
1892 goto error;
1893 }
1894 }
1895
1896 error:
1897 rcu_read_unlock();
1898 return status;
1899 }
1900
1901 enum lttng_error_code kernel_create_channel_subdirectories(
1902 const struct ltt_kernel_session *ksess)
1903 {
1904 enum lttng_error_code ret = LTTNG_OK;
1905 enum lttng_trace_chunk_status chunk_status;
1906
1907 rcu_read_lock();
1908 assert(ksess->current_trace_chunk);
1909
1910 /*
1911 * Create the index subdirectory which will take care
1912 * of implicitly creating the channel's path.
1913 */
1914 chunk_status = lttng_trace_chunk_create_subdirectory(
1915 ksess->current_trace_chunk,
1916 DEFAULT_KERNEL_TRACE_DIR "/" DEFAULT_INDEX_DIR);
1917 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1918 ret = LTTNG_ERR_CREATE_DIR_FAIL;
1919 goto error;
1920 }
1921 error:
1922 rcu_read_unlock();
1923 return ret;
1924 }
1925
1926 /*
1927 * Setup necessary data for kernel tracer action.
1928 */
1929 LTTNG_HIDDEN
1930 int init_kernel_tracer(void)
1931 {
1932 int ret;
1933 bool is_root = !getuid();
1934
1935 /* Modprobe lttng kernel modules */
1936 ret = modprobe_lttng_control();
1937 if (ret < 0) {
1938 goto error;
1939 }
1940
1941 /* Open debugfs lttng */
1942 kernel_tracer_fd = open(module_proc_lttng, O_RDWR);
1943 if (kernel_tracer_fd < 0) {
1944 DBG("Failed to open %s", module_proc_lttng);
1945 goto error_open;
1946 }
1947
1948 /* Validate kernel version */
1949 ret = kernel_validate_version(&kernel_tracer_version,
1950 &kernel_tracer_abi_version);
1951 if (ret < 0) {
1952 goto error_version;
1953 }
1954
1955 ret = modprobe_lttng_data();
1956 if (ret < 0) {
1957 goto error_modules;
1958 }
1959
1960 ret = kernel_supports_ring_buffer_snapshot_sample_positions();
1961 if (ret < 0) {
1962 goto error_modules;
1963 }
1964 if (ret < 1) {
1965 WARN("Kernel tracer does not support buffer monitoring. "
1966 "The monitoring timer of channels in the kernel domain "
1967 "will be set to 0 (disabled).");
1968 }
1969
1970 ret = kernel_supports_event_notifiers();
1971 if (ret < 0) {
1972 ERR("Failed to check for kernel tracer event notifier support");
1973 goto error_modules;
1974 }
1975 ret = kernel_create_event_notifier_group(&kernel_tracer_event_notifier_group_fd);
1976 if (ret < 0) {
1977 /* This is not fatal. */
1978 WARN("Failed to create kernel event notifier group");
1979 kernel_tracer_event_notifier_group_fd = -1;
1980 } else {
1981 enum event_notifier_error_accounting_status error_accounting_status;
1982 enum lttng_error_code error_code_ret =
1983 kernel_create_event_notifier_group_notification_fd(
1984 &kernel_tracer_event_notifier_group_notification_fd);
1985
1986 if (error_code_ret != LTTNG_OK) {
1987 goto error_modules;
1988 }
1989
1990 error_accounting_status = event_notifier_error_accounting_register_kernel(
1991 kernel_tracer_event_notifier_group_fd);
1992 if (error_accounting_status != EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_OK) {
1993 ERR("Failed to initialize event notifier error accounting for kernel tracer");
1994 error_code_ret = LTTNG_ERR_EVENT_NOTIFIER_ERROR_ACCOUNTING;
1995 goto error_modules;
1996 }
1997
1998 kernel_token_to_event_notifier_rule_ht = cds_lfht_new(
1999 DEFAULT_HT_SIZE, 1, 0,
2000 CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING,
2001 NULL);
2002 if (!kernel_token_to_event_notifier_rule_ht) {
2003 goto error_token_ht;
2004 }
2005 }
2006
2007 DBG("Kernel tracer initialized: kernel tracer fd = %d, event notifier group fd = %d, event notifier group notification fd = %d",
2008 kernel_tracer_fd, kernel_tracer_event_notifier_group_fd,
2009 kernel_tracer_event_notifier_group_notification_fd);
2010
2011 ret = syscall_init_table(kernel_tracer_fd);
2012 if (ret < 0) {
2013 ERR("Unable to populate syscall table. Syscall tracing won't "
2014 "work for this session daemon.");
2015 }
2016
2017 return 0;
2018
2019 error_version:
2020 modprobe_remove_lttng_control();
2021 ret = close(kernel_tracer_fd);
2022 if (ret) {
2023 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2024 kernel_tracer_fd);
2025 }
2026
2027 kernel_tracer_fd = -1;
2028 return LTTNG_ERR_KERN_VERSION;
2029
2030
2031 error_token_ht:
2032 ret = close(kernel_tracer_event_notifier_group_notification_fd);
2033 if (ret) {
2034 PERROR("Failed to close kernel tracer event notifier group notification file descriptor: fd = %d",
2035 kernel_tracer_event_notifier_group_notification_fd);
2036 }
2037
2038 kernel_tracer_event_notifier_group_notification_fd = -1;
2039
2040 error_modules:
2041 ret = close(kernel_tracer_event_notifier_group_fd);
2042 if (ret) {
2043 PERROR("Failed to close kernel tracer event notifier group file descriptor: fd = %d",
2044 kernel_tracer_event_notifier_group_fd);
2045 }
2046
2047 kernel_tracer_event_notifier_group_fd = -1;
2048
2049 ret = close(kernel_tracer_fd);
2050 if (ret) {
2051 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2052 kernel_tracer_fd);
2053 }
2054
2055 kernel_tracer_fd = -1;
2056
2057 error_open:
2058 modprobe_remove_lttng_control();
2059
2060 error:
2061 WARN("No kernel tracer available");
2062 kernel_tracer_fd = -1;
2063 if (!is_root) {
2064 return LTTNG_ERR_NEED_ROOT_SESSIOND;
2065 } else {
2066 return LTTNG_ERR_KERN_NA;
2067 }
2068 }
2069
2070 LTTNG_HIDDEN
2071 void cleanup_kernel_tracer(void)
2072 {
2073 DBG2("Closing kernel event notifier group notification file descriptor");
2074 if (kernel_tracer_event_notifier_group_notification_fd >= 0) {
2075 int ret = notification_thread_command_remove_tracer_event_source(
2076 notification_thread_handle,
2077 kernel_tracer_event_notifier_group_notification_fd);
2078 if (ret != LTTNG_OK) {
2079 ERR("Failed to remove kernel event notifier notification from notification thread");
2080 }
2081
2082 ret = close(kernel_tracer_event_notifier_group_notification_fd);
2083 if (ret) {
2084 PERROR("Failed to close kernel event notifier group notification file descriptor: fd = %d",
2085 kernel_tracer_event_notifier_group_notification_fd);
2086 }
2087
2088 kernel_tracer_event_notifier_group_notification_fd = -1;
2089 }
2090
2091 if (kernel_token_to_event_notifier_rule_ht) {
2092 const int ret = cds_lfht_destroy(
2093 kernel_token_to_event_notifier_rule_ht, NULL);
2094 assert(ret == 0);
2095 }
2096
2097 DBG2("Closing kernel event notifier group file descriptor");
2098 if (kernel_tracer_event_notifier_group_fd >= 0) {
2099 const int ret = close(kernel_tracer_event_notifier_group_fd);
2100
2101 if (ret) {
2102 PERROR("Failed to close kernel event notifier group file descriptor: fd = %d",
2103 kernel_tracer_event_notifier_group_fd);
2104 }
2105
2106 kernel_tracer_event_notifier_group_fd = -1;
2107 }
2108
2109 DBG2("Closing kernel fd");
2110 if (kernel_tracer_fd >= 0) {
2111 const int ret = close(kernel_tracer_fd);
2112
2113 if (ret) {
2114 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2115 kernel_tracer_fd);
2116 }
2117
2118 kernel_tracer_fd = -1;
2119 }
2120
2121 free(syscall_table);
2122 }
2123
2124 LTTNG_HIDDEN
2125 bool kernel_tracer_is_initialized(void)
2126 {
2127 return kernel_tracer_fd >= 0;
2128 }
2129
2130 /*
2131 * Clear a kernel session.
2132 *
2133 * Return LTTNG_OK on success or else an LTTng error code.
2134 */
2135 enum lttng_error_code kernel_clear_session(struct ltt_session *session)
2136 {
2137 int ret;
2138 enum lttng_error_code status = LTTNG_OK;
2139 struct consumer_socket *socket;
2140 struct lttng_ht_iter iter;
2141 struct ltt_kernel_session *ksess = session->kernel_session;
2142
2143 assert(ksess);
2144 assert(ksess->consumer);
2145
2146 DBG("Clear kernel session %s (session %" PRIu64 ")",
2147 session->name, session->id);
2148
2149 rcu_read_lock();
2150
2151 if (ksess->active) {
2152 ERR("Expecting inactive session %s (%" PRIu64 ")", session->name, session->id);
2153 status = LTTNG_ERR_FATAL;
2154 goto end;
2155 }
2156
2157 /*
2158 * Note that this loop will end after one iteration given that there is
2159 * only one kernel consumer.
2160 */
2161 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
2162 socket, node.node) {
2163 struct ltt_kernel_channel *chan;
2164
2165 /* For each channel, ask the consumer to clear it. */
2166 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
2167 DBG("Clear kernel channel %" PRIu64 ", session %s",
2168 chan->key, session->name);
2169 ret = consumer_clear_channel(socket, chan->key);
2170 if (ret < 0) {
2171 goto error;
2172 }
2173 }
2174
2175 if (!ksess->metadata) {
2176 /*
2177 * Nothing to do for the metadata.
2178 * This is a snapshot session.
2179 * The metadata is genererated on the fly.
2180 */
2181 continue;
2182 }
2183
2184 /*
2185 * Clear the metadata channel.
2186 * Metadata channel is not cleared per se but we still need to
2187 * perform a rotation operation on it behind the scene.
2188 */
2189 ret = consumer_clear_channel(socket, ksess->metadata->key);
2190 if (ret < 0) {
2191 goto error;
2192 }
2193 }
2194
2195 goto end;
2196 error:
2197 switch (-ret) {
2198 case LTTCOMM_CONSUMERD_RELAYD_CLEAR_DISALLOWED:
2199 status = LTTNG_ERR_CLEAR_RELAY_DISALLOWED;
2200 break;
2201 default:
2202 status = LTTNG_ERR_CLEAR_FAIL_CONSUMER;
2203 break;
2204 }
2205 end:
2206 rcu_read_unlock();
2207 return status;
2208 }
2209
2210 enum lttng_error_code kernel_create_event_notifier_group_notification_fd(
2211 int *event_notifier_group_notification_fd)
2212 {
2213 int local_fd = -1, ret;
2214 enum lttng_error_code error_code_ret;
2215
2216 assert(event_notifier_group_notification_fd);
2217
2218 ret = kernctl_create_event_notifier_group_notification_fd(
2219 kernel_tracer_event_notifier_group_fd);
2220 if (ret < 0) {
2221 PERROR("Failed to create kernel event notifier group notification file descriptor");
2222 error_code_ret = LTTNG_ERR_EVENT_NOTIFIER_GROUP_NOTIFICATION_FD;
2223 goto error;
2224 }
2225
2226 local_fd = ret;
2227
2228 /* Prevent fd duplication after execlp(). */
2229 ret = fcntl(local_fd, F_SETFD, FD_CLOEXEC);
2230 if (ret < 0) {
2231 PERROR("Failed to set FD_CLOEXEC on kernel event notifier group notification file descriptor: fd = %d",
2232 local_fd);
2233 error_code_ret = LTTNG_ERR_EVENT_NOTIFIER_GROUP_NOTIFICATION_FD;
2234 goto error;
2235 }
2236
2237 DBG("Created kernel notifier group notification file descriptor: fd = %d",
2238 local_fd);
2239 error_code_ret = LTTNG_OK;
2240 *event_notifier_group_notification_fd = local_fd;
2241 local_fd = -1;
2242
2243 error:
2244 if (local_fd >= 0) {
2245 ret = close(local_fd);
2246 if (ret) {
2247 PERROR("Failed to close kernel event notifier group notification file descriptor: fd = %d",
2248 local_fd);
2249 }
2250 }
2251
2252 return error_code_ret;
2253 }
2254
2255 enum lttng_error_code kernel_destroy_event_notifier_group_notification_fd(
2256 int event_notifier_group_notification_fd)
2257 {
2258 enum lttng_error_code ret_code = LTTNG_OK;
2259
2260 DBG("Closing event notifier group notification file descriptor: fd = %d",
2261 event_notifier_group_notification_fd);
2262 if (event_notifier_group_notification_fd >= 0) {
2263 const int ret = close(event_notifier_group_notification_fd);
2264 if (ret) {
2265 PERROR("Failed to close event notifier group notification file descriptor: fd = %d",
2266 event_notifier_group_notification_fd);
2267 }
2268 }
2269
2270 return ret_code;
2271 }
2272
2273 static
2274 unsigned long hash_trigger(const struct lttng_trigger *trigger)
2275 {
2276 const struct lttng_condition *condition =
2277 lttng_trigger_get_const_condition(trigger);
2278
2279 return lttng_condition_hash(condition);
2280 }
2281
2282 static
2283 int match_trigger(struct cds_lfht_node *node, const void *key)
2284 {
2285 const struct ltt_kernel_event_notifier_rule *event_notifier_rule;
2286 const struct lttng_trigger *trigger = key;
2287
2288 event_notifier_rule = caa_container_of(node,
2289 const struct ltt_kernel_event_notifier_rule, ht_node);
2290
2291 return lttng_trigger_is_equal(trigger, event_notifier_rule->trigger);
2292 }
2293
2294 static enum lttng_error_code kernel_create_event_notifier_rule(
2295 struct lttng_trigger *trigger,
2296 const struct lttng_credentials *creds, uint64_t token)
2297 {
2298 int err, fd, ret = 0;
2299 enum lttng_error_code error_code_ret;
2300 enum lttng_condition_status condition_status;
2301 enum lttng_condition_type condition_type;
2302 enum lttng_event_rule_type event_rule_type;
2303 struct ltt_kernel_event_notifier_rule *event_notifier_rule;
2304 struct lttng_kernel_event_notifier kernel_event_notifier = {};
2305 unsigned int capture_bytecode_count = 0, i;
2306 const struct lttng_condition *condition = NULL;
2307 const struct lttng_event_rule *event_rule = NULL;
2308 enum lttng_condition_status cond_status;
2309
2310 assert(trigger);
2311
2312 condition = lttng_trigger_get_const_condition(trigger);
2313 assert(condition);
2314
2315 condition_type = lttng_condition_get_type(condition);
2316 assert(condition_type == LTTNG_CONDITION_TYPE_ON_EVENT);
2317
2318 /* Does not acquire a reference. */
2319 condition_status = lttng_condition_on_event_get_rule(
2320 condition, &event_rule);
2321 assert(condition_status == LTTNG_CONDITION_STATUS_OK);
2322 assert(event_rule);
2323
2324 event_rule_type = lttng_event_rule_get_type(event_rule);
2325 assert(event_rule_type != LTTNG_EVENT_RULE_TYPE_UNKNOWN);
2326
2327 error_code_ret = trace_kernel_create_event_notifier_rule(trigger, token,
2328 lttng_condition_on_event_get_error_counter_index(condition),
2329 &event_notifier_rule);
2330 if (error_code_ret != LTTNG_OK) {
2331 goto error;
2332 }
2333
2334 error_code_ret = trace_kernel_init_event_notifier_from_event_rule(
2335 event_rule, &kernel_event_notifier);
2336 if (error_code_ret != LTTNG_OK) {
2337 goto free_event;
2338 }
2339
2340 kernel_event_notifier.event.token = event_notifier_rule->token;
2341 kernel_event_notifier.error_counter_idx =
2342 lttng_condition_on_event_get_error_counter_index(condition);
2343
2344 fd = kernctl_create_event_notifier(
2345 kernel_tracer_event_notifier_group_fd,
2346 &kernel_event_notifier);
2347 if (fd < 0) {
2348 switch (-fd) {
2349 case EEXIST:
2350 error_code_ret = LTTNG_ERR_KERN_EVENT_EXIST;
2351 break;
2352 case ENOSYS:
2353 WARN("Failed to create kernel event notifier: not notifier type not implemented");
2354 error_code_ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
2355 break;
2356 case ENOENT:
2357 WARN("Failed to create kernel event notifier: not found: name = '%s'",
2358 kernel_event_notifier.event.name);
2359 error_code_ret = LTTNG_ERR_KERN_ENABLE_FAIL;
2360 break;
2361 default:
2362 PERROR("Failed to create kernel event notifier: error code = %d, name = '%s'",
2363 fd, kernel_event_notifier.event.name);
2364 error_code_ret = LTTNG_ERR_KERN_ENABLE_FAIL;
2365 }
2366 goto free_event;
2367 }
2368
2369 event_notifier_rule->fd = fd;
2370 /* Prevent fd duplication after execlp(). */
2371 err = fcntl(event_notifier_rule->fd, F_SETFD, FD_CLOEXEC);
2372 if (err < 0) {
2373 PERROR("Failed to set FD_CLOEXEC on kernel event notifier file descriptor: fd = %d",
2374 fd);
2375 error_code_ret = LTTNG_ERR_FATAL;
2376 goto set_cloexec_error;
2377 }
2378
2379 if (event_notifier_rule->filter) {
2380 err = kernctl_filter(event_notifier_rule->fd, event_notifier_rule->filter);
2381 if (err < 0) {
2382 switch (-err) {
2383 case ENOMEM:
2384 error_code_ret = LTTNG_ERR_FILTER_NOMEM;
2385 break;
2386 default:
2387 error_code_ret = LTTNG_ERR_FILTER_INVAL;
2388 break;
2389 }
2390 goto filter_error;
2391 }
2392 }
2393
2394 if (lttng_event_rule_get_type(event_rule) ==
2395 LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE) {
2396 ret = userspace_probe_event_rule_add_callsites(
2397 event_rule, creds, event_notifier_rule->fd);
2398 if (ret) {
2399 error_code_ret = LTTNG_ERR_KERN_ENABLE_FAIL;
2400 goto add_callsite_error;
2401 }
2402 }
2403
2404 /* Set the capture bytecode if any. */
2405 cond_status = lttng_condition_on_event_get_capture_descriptor_count(
2406 condition, &capture_bytecode_count);
2407 assert(cond_status == LTTNG_CONDITION_STATUS_OK);
2408
2409 for (i = 0; i < capture_bytecode_count; i++) {
2410 const struct lttng_bytecode *capture_bytecode =
2411 lttng_condition_on_event_get_capture_bytecode_at_index(
2412 condition, i);
2413
2414 if (capture_bytecode == NULL) {
2415 ERR("Unexpected NULL capture bytecode on condition");
2416 error_code_ret = LTTNG_ERR_KERN_ENABLE_FAIL;
2417 goto capture_error;
2418 }
2419
2420 ret = kernctl_capture(event_notifier_rule->fd, capture_bytecode);
2421 if (ret < 0) {
2422 ERR("Failed to set capture bytecode on event notifier rule fd: fd = %d",
2423 event_notifier_rule->fd);
2424 error_code_ret = LTTNG_ERR_KERN_ENABLE_FAIL;
2425 goto capture_error;
2426 }
2427 }
2428
2429 err = kernctl_enable(event_notifier_rule->fd);
2430 if (err < 0) {
2431 switch (-err) {
2432 case EEXIST:
2433 error_code_ret = LTTNG_ERR_KERN_EVENT_EXIST;
2434 break;
2435 default:
2436 PERROR("enable kernel event notifier");
2437 error_code_ret = LTTNG_ERR_KERN_ENABLE_FAIL;
2438 break;
2439 }
2440 goto enable_error;
2441 }
2442
2443 /* Add trigger to kernel token mapping in the hash table. */
2444 rcu_read_lock();
2445 cds_lfht_add(kernel_token_to_event_notifier_rule_ht, hash_trigger(trigger),
2446 &event_notifier_rule->ht_node);
2447 rcu_read_unlock();
2448
2449 DBG("Created kernel event notifier: name = '%s', fd = %d",
2450 kernel_event_notifier.event.name,
2451 event_notifier_rule->fd);
2452
2453 return LTTNG_OK;
2454
2455 capture_error:
2456 add_callsite_error:
2457 enable_error:
2458 set_cloexec_error:
2459 filter_error:
2460 {
2461 const int close_ret = close(event_notifier_rule->fd);
2462
2463 if (close_ret) {
2464 PERROR("Failed to close kernel event notifier file descriptor: fd = %d",
2465 event_notifier_rule->fd);
2466 }
2467 }
2468 free_event:
2469 free(event_notifier_rule);
2470 error:
2471 return error_code_ret;
2472 }
2473
2474 enum lttng_error_code kernel_register_event_notifier(
2475 struct lttng_trigger *trigger,
2476 const struct lttng_credentials *cmd_creds)
2477 {
2478 enum lttng_error_code ret;
2479 enum lttng_condition_status status;
2480 enum lttng_domain_type domain_type;
2481 const struct lttng_event_rule *event_rule;
2482 const struct lttng_condition *const condition =
2483 lttng_trigger_get_const_condition(trigger);
2484 const uint64_t token = lttng_trigger_get_tracer_token(trigger);
2485
2486 assert(condition);
2487
2488 /* Does not acquire a reference to the event rule. */
2489 status = lttng_condition_on_event_get_rule(
2490 condition, &event_rule);
2491 assert(status == LTTNG_CONDITION_STATUS_OK);
2492
2493 domain_type = lttng_event_rule_get_domain_type(event_rule);
2494 assert(domain_type == LTTNG_DOMAIN_KERNEL);
2495
2496 ret = kernel_create_event_notifier_rule(trigger, cmd_creds, token);
2497 if (ret != LTTNG_OK) {
2498 ERR("Failed to create kernel event notifier rule");
2499 }
2500
2501 return ret;
2502 }
2503
2504 enum lttng_error_code kernel_unregister_event_notifier(
2505 const struct lttng_trigger *trigger)
2506 {
2507 struct ltt_kernel_event_notifier_rule *token_event_rule_element;
2508 struct cds_lfht_node *node;
2509 struct cds_lfht_iter iter;
2510 enum lttng_error_code error_code_ret;
2511 int ret;
2512
2513 rcu_read_lock();
2514
2515 cds_lfht_lookup(kernel_token_to_event_notifier_rule_ht,
2516 hash_trigger(trigger), match_trigger, trigger, &iter);
2517
2518 node = cds_lfht_iter_get_node(&iter);
2519 if (!node) {
2520 error_code_ret = LTTNG_ERR_TRIGGER_NOT_FOUND;
2521 goto error;
2522 }
2523
2524 token_event_rule_element = caa_container_of(node,
2525 struct ltt_kernel_event_notifier_rule, ht_node);
2526
2527 ret = kernel_disable_event_notifier_rule(token_event_rule_element);
2528 if (ret) {
2529 error_code_ret = LTTNG_ERR_FATAL;
2530 goto error;
2531 }
2532
2533 trace_kernel_destroy_event_notifier_rule(token_event_rule_element);
2534 error_code_ret = LTTNG_OK;
2535
2536 error:
2537 rcu_read_unlock();
2538
2539 return error_code_ret;
2540 }
2541
2542 int kernel_get_notification_fd(void)
2543 {
2544 return kernel_tracer_event_notifier_group_notification_fd;
2545 }
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