Fix: sessiond: kernel: invalid error code check
[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c
CommitLineData
20fe2104 1/*
ab5be9fa 2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
20fe2104 3 *
ab5be9fa 4 * SPDX-License-Identifier: GPL-2.0-only
20fe2104 5 *
20fe2104
DG
6 */
7
6c1c0768 8#define _LGPL_SOURCE
7b395890 9#include <fcntl.h>
20fe2104
DG
10#include <stdlib.h>
11#include <stdio.h>
f34daff7 12#include <string.h>
8c0faa1d 13#include <unistd.h>
77c7c900 14#include <inttypes.h>
7d268848 15#include <sys/types.h>
20fe2104 16
990570ed 17#include <common/common.h>
352b58f5 18#include <common/hashtable/utils.h>
82b69413 19#include <common/trace-chunk.h>
db758600 20#include <common/kernel-ctl/kernel-ctl.h>
c052142c 21#include <common/kernel-ctl/kernel-ioctl.h>
42224349 22#include <common/sessiond-comm/sessiond-comm.h>
c5bf436c
JG
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>
1e307fab 28
352b58f5
JR
29#include <lttng/userspace-probe.h>
30#include <lttng/userspace-probe-internal.h>
e393070a
JR
31#include <lttng/condition/on-event.h>
32#include <lttng/condition/on-event-internal.h>
352b58f5
JR
33#include <lttng/event-rule/event-rule.h>
34#include <lttng/event-rule/event-rule-internal.h>
e957bf98 35#include <lttng/event-rule/userspace-probe-internal.h>
352b58f5 36
90aa04a1 37#include "event-notifier-error-accounting.h"
7d268848
MD
38#include "lttng-sessiond.h"
39#include "lttng-syscall.h"
352b58f5 40#include "condition-internal.h"
2f77fc4b 41#include "consumer.h"
4771f025 42#include "kernel.h"
6dc3064a 43#include "kernel-consumer.h"
096102bd 44#include "kern-modules.h"
90aa04a1 45#include "sessiond-config.h"
834978fd 46#include "utils.h"
5c408ad8 47#include "rotate.h"
7d268848 48#include "modprobe.h"
c5bf436c 49#include "tracker.h"
352b58f5 50#include "notification-thread-commands.h"
20fe2104 51
e1f3997a
JD
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 */
56static uint64_t next_kernel_channel_key;
57
7d268848
MD
58static const char *module_proc_lttng = "/proc/lttng";
59
60static int kernel_tracer_fd = -1;
352b58f5
JR
61static int kernel_tracer_event_notifier_group_fd = -1;
62static int kernel_tracer_event_notifier_group_notification_fd = -1;
63static struct cds_lfht *kernel_token_to_event_notifier_rule_ht;
7d268848 64
d65106b1 65/*
050349bb 66 * Add context on a kernel channel.
df3c77c8
JG
67 *
68 * Assumes the ownership of ctx.
d65106b1
DG
69 */
70int kernel_add_channel_context(struct ltt_kernel_channel *chan,
645328ae 71 struct ltt_kernel_context *ctx)
d65106b1
DG
72{
73 int ret;
74
0525e9ae
DG
75 assert(chan);
76 assert(ctx);
77
d65106b1 78 DBG("Adding context to channel %s", chan->channel->name);
645328ae 79 ret = kernctl_add_context(chan->fd, &ctx->ctx);
d65106b1 80 if (ret < 0) {
32af2c95 81 switch (-ret) {
1ae5e83e
JD
82 case ENOSYS:
83 /* Exists but not available for this kernel */
84 ret = LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE;
85 goto error;
86 case EEXIST:
b579acd9
DG
87 /* If EEXIST, we just ignore the error */
88 ret = 0;
1ae5e83e
JD
89 goto end;
90 default:
91 PERROR("add context ioctl");
92 ret = LTTNG_ERR_KERN_CONTEXT_FAIL;
93 goto error;
b579acd9 94 }
d65106b1 95 }
21ed98c1 96 ret = 0;
d65106b1 97
1ae5e83e 98end:
645328ae 99 cds_list_add_tail(&ctx->list, &chan->ctx_list);
ba985c3a 100 ctx->in_list = true;
df3c77c8 101 ctx = NULL;
d65106b1 102error:
df3c77c8
JG
103 if (ctx) {
104 trace_kernel_destroy_context(ctx);
105 }
d65106b1
DG
106 return ret;
107}
108
20fe2104 109/*
050349bb
DG
110 * Create a new kernel session, register it to the kernel tracer and add it to
111 * the session daemon session.
20fe2104 112 */
7d268848 113int kernel_create_session(struct ltt_session *session)
20fe2104
DG
114{
115 int ret;
116 struct ltt_kernel_session *lks;
117
0525e9ae
DG
118 assert(session);
119
54012638 120 /* Allocate data structure */
dec56f6c 121 lks = trace_kernel_create_session();
20fe2104 122 if (lks == NULL) {
54012638 123 ret = -1;
20fe2104
DG
124 goto error;
125 }
126
54012638 127 /* Kernel tracer session creation */
7d268848 128 ret = kernctl_create_session(kernel_tracer_fd);
20fe2104 129 if (ret < 0) {
df0f840b 130 PERROR("ioctl kernel create session");
20fe2104
DG
131 goto error;
132 }
133
20fe2104 134 lks->fd = ret;
7b395890
DG
135 /* Prevent fd duplication after execlp() */
136 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
137 if (ret < 0) {
df0f840b 138 PERROR("fcntl session fd");
7b395890
DG
139 }
140
53632229 141 lks->id = session->id;
3bd1e081 142 lks->consumer_fds_sent = 0;
8c0faa1d 143 session->kernel_session = lks;
8c0faa1d
DG
144
145 DBG("Kernel session created (fd: %d)", lks->fd);
20fe2104 146
8ff4109e
JR
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
e04b2181
JR
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
20fe2104
DG
167 return 0;
168
169error:
5f62c685
DG
170 if (lks) {
171 trace_kernel_destroy_session(lks);
d070c424 172 trace_kernel_free_session(lks);
5f62c685 173 }
20fe2104
DG
174 return ret;
175}
176
177/*
050349bb
DG
178 * Create a kernel channel, register it to the kernel tracer and add it to the
179 * kernel session.
20fe2104 180 */
050349bb 181int kernel_create_channel(struct ltt_kernel_session *session,
fdd9eb17 182 struct lttng_channel *chan)
20fe2104
DG
183{
184 int ret;
185 struct ltt_kernel_channel *lkc;
20fe2104 186
0525e9ae
DG
187 assert(session);
188 assert(chan);
0525e9ae 189
54012638 190 /* Allocate kernel channel */
fdd9eb17 191 lkc = trace_kernel_create_channel(chan);
54012638 192 if (lkc == NULL) {
20fe2104
DG
193 goto error;
194 }
195
ecc48a90 196 DBG3("Kernel create channel %s with attr: %d, %" PRIu64 ", %" PRIu64 ", %u, %u, %d, %d",
fdd9eb17 197 chan->name, lkc->channel->attr.overwrite,
173af62f
DG
198 lkc->channel->attr.subbuf_size, lkc->channel->attr.num_subbuf,
199 lkc->channel->attr.switch_timer_interval, lkc->channel->attr.read_timer_interval,
ecc48a90 200 lkc->channel->attr.live_timer_interval, lkc->channel->attr.output);
173af62f 201
54012638 202 /* Kernel tracer channel creation */
f3ed775e 203 ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
20fe2104 204 if (ret < 0) {
df0f840b 205 PERROR("ioctl kernel create channel");
20fe2104
DG
206 goto error;
207 }
208
54012638 209 /* Setup the channel fd */
20fe2104 210 lkc->fd = ret;
7b395890
DG
211 /* Prevent fd duplication after execlp() */
212 ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
213 if (ret < 0) {
df0f840b 214 PERROR("fcntl session fd");
7b395890
DG
215 }
216
54012638 217 /* Add channel to session */
8c0faa1d
DG
218 cds_list_add(&lkc->list, &session->channel_list.head);
219 session->channel_count++;
fb5f35b6 220 lkc->session = session;
e1f3997a 221 lkc->key = ++next_kernel_channel_key;
20fe2104 222
e1f3997a
JD
223 DBG("Kernel channel %s created (fd: %d, key: %" PRIu64 ")",
224 lkc->channel->name, lkc->fd, lkc->key);
20fe2104
DG
225
226 return 0;
227
228error:
5f62c685
DG
229 if (lkc) {
230 free(lkc->channel);
231 free(lkc);
232 }
54012638 233 return -1;
20fe2104 234}
f34daff7 235
352b58f5
JR
236/*
237 * Create a kernel event notifier group, register it to the kernel tracer and
238 * add it to the kernel session.
239 */
240static 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;
269error:
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
410b78a0
FD
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 */
289static
290int extract_userspace_probe_offset_function_elf(
87597c2c 291 const struct lttng_userspace_probe_location *probe_location,
0a398bc4 292 uid_t uid, gid_t gid, uint64_t *offset)
410b78a0
FD
293{
294 int fd;
295 int ret = 0;
296 const char *symbol = NULL;
87597c2c 297 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
410b78a0
FD
298 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type;
299
410b78a0
FD
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
0a398bc4 329 ret = run_as_extract_elf_symbol_offset(fd, symbol, uid, gid, offset);
410b78a0
FD
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));
337end:
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 */
350static
351int extract_userspace_probe_offset_tracepoint_sdt(
87597c2c 352 const struct lttng_userspace_probe_location *probe_location,
0a398bc4 353 uid_t uid, gid_t gid, uint64_t **offsets,
410b78a0
FD
354 uint32_t *offsets_count)
355{
356 enum lttng_userspace_probe_location_lookup_method_type lookup_method_type;
87597c2c 357 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
410b78a0
FD
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,
0a398bc4 399 uid, gid, offsets, offsets_count);
410b78a0
FD
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 }
416end:
417 return ret;
418}
419
410b78a0 420static
0a398bc4
FD
421int userspace_probe_add_callsite(
422 const struct lttng_userspace_probe_location *location,
423 uid_t uid, gid_t gid, int fd)
410b78a0 424{
87597c2c 425 const struct lttng_userspace_probe_location_lookup_method *lookup_method = NULL;
410b78a0 426 enum lttng_userspace_probe_location_lookup_method_type type;
410b78a0
FD
427 int ret;
428
0a398bc4 429 lookup_method = lttng_userspace_probe_location_get_lookup_method(location);
410b78a0
FD
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
0a398bc4
FD
442 ret = extract_userspace_probe_offset_function_elf(location,
443 uid, gid, &offset);
410b78a0
FD
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) {
0a398bc4 452 WARN("Failed to add callsite to ELF userspace probe.");
410b78a0
FD
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 */
0a398bc4
FD
469 ret = extract_userspace_probe_offset_tracepoint_sdt(location,
470 uid, gid, &offsets, &offsets_count);
410b78a0
FD
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) {
0a398bc4 479 WARN("Failed to add callsite to SDT userspace probe");
410b78a0
FD
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 }
492end:
493 return ret;
494}
495
0a398bc4
FD
496/*
497 * Extract the offsets of the instrumentation point for the different lookup
498 * methods.
499 */
500static
501int 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
523end:
524 return ret;
525}
526
352b58f5
JR
527/*
528 * Extract the offsets of the instrumentation point for the different look-up
529 * methods.
530 */
531static 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);
1f1567a5 545 assert(event_rule_type == LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE);
352b58f5 546
1f1567a5 547 status = lttng_event_rule_userspace_probe_get_location(rule, &location);
352b58f5
JR
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
561end:
562 return ret;
563}
564
f34daff7 565/*
050349bb
DG
566 * Create a kernel event, enable it to the kernel tracer and add it to the
567 * channel event list of the kernel session.
49d21f93 568 * We own filter_expression and filter.
f34daff7 569 */
050349bb 570int kernel_create_event(struct lttng_event *ev,
00a62084
MD
571 struct ltt_kernel_channel *channel,
572 char *filter_expression,
2b00d462 573 struct lttng_bytecode *filter)
f34daff7 574{
71a3bb01
FD
575 int err, fd;
576 enum lttng_error_code ret;
f34daff7 577 struct ltt_kernel_event *event;
f34daff7 578
0525e9ae
DG
579 assert(ev);
580 assert(channel);
581
a969e101 582 /* We pass ownership of filter_expression and filter */
71a3bb01
FD
583 ret = trace_kernel_create_event(ev, filter_expression,
584 filter, &event);
585 if (ret != LTTNG_OK) {
f34daff7
DG
586 goto error;
587 }
588
71a3bb01
FD
589 fd = kernctl_create_event(channel->fd, event->event);
590 if (fd < 0) {
591 switch (-fd) {
bd29c13d 592 case EEXIST:
71a3bb01 593 ret = LTTNG_ERR_KERN_EVENT_EXIST;
bd29c13d
DG
594 break;
595 case ENOSYS:
596 WARN("Event type not implemented");
71a3bb01 597 ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
bd29c13d 598 break;
8197a339
DG
599 case ENOENT:
600 WARN("Event %s not found!", ev->name);
71a3bb01 601 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
8197a339 602 break;
bd29c13d 603 default:
71a3bb01 604 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
d87bfb32
DG
605 PERROR("create event ioctl");
606 }
e953ef25 607 goto free_event;
8c0faa1d 608 }
f34daff7 609
d0ae4ea8 610 event->type = ev->type;
71a3bb01 611 event->fd = fd;
7b395890 612 /* Prevent fd duplication after execlp() */
71a3bb01
FD
613 err = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
614 if (err < 0) {
df0f840b 615 PERROR("fcntl session fd");
7b395890
DG
616 }
617
00a62084 618 if (filter) {
71a3bb01
FD
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 }
00a62084
MD
629 goto filter_error;
630 }
631 }
632
dcabc190 633 if (ev->type == LTTNG_EVENT_USERSPACE_PROBE) {
0a398bc4
FD
634 ret = userspace_probe_event_add_callsites(ev, channel->session,
635 event->fd);
dcabc190
FD
636 if (ret) {
637 goto add_callsite_error;
638 }
639 }
640
71a3bb01
FD
641 err = kernctl_enable(event->fd);
642 if (err < 0) {
643 switch (-err) {
00a62084
MD
644 case EEXIST:
645 ret = LTTNG_ERR_KERN_EVENT_EXIST;
646 break;
647 default:
648 PERROR("enable kernel event");
71a3bb01 649 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
00a62084
MD
650 break;
651 }
652 goto enable_error;
653 }
654
f3ed775e
DG
655 /* Add event to event list */
656 cds_list_add(&event->list, &channel->events_list.head);
cbbbb275
DG
657 channel->event_count++;
658
e953ef25
DG
659 DBG("Event %s created (fd: %d)", ev->name, event->fd);
660
661 return 0;
662
dcabc190 663add_callsite_error:
00a62084
MD
664enable_error:
665filter_error:
666 {
667 int closeret;
668
669 closeret = close(event->fd);
670 if (closeret) {
671 PERROR("close event fd");
672 }
673 }
e953ef25
DG
674free_event:
675 free(event);
676error:
d87bfb32 677 return ret;
e953ef25
DG
678}
679
26cc6b4e 680/*
050349bb 681 * Disable a kernel channel.
26cc6b4e
DG
682 */
683int kernel_disable_channel(struct ltt_kernel_channel *chan)
684{
685 int ret;
686
0525e9ae
DG
687 assert(chan);
688
26cc6b4e
DG
689 ret = kernctl_disable(chan->fd);
690 if (ret < 0) {
df0f840b 691 PERROR("disable chan ioctl");
26cc6b4e
DG
692 goto error;
693 }
694
695 chan->enabled = 0;
e1f3997a
JD
696 DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64 ")",
697 chan->channel->name, chan->fd, chan->key);
26cc6b4e
DG
698
699 return 0;
700
701error:
702 return ret;
703}
704
d36b8583 705/*
050349bb 706 * Enable a kernel channel.
d36b8583
DG
707 */
708int kernel_enable_channel(struct ltt_kernel_channel *chan)
709{
710 int ret;
711
0525e9ae
DG
712 assert(chan);
713
d36b8583 714 ret = kernctl_enable(chan->fd);
32af2c95 715 if (ret < 0 && ret != -EEXIST) {
df0f840b 716 PERROR("Enable kernel chan");
d36b8583
DG
717 goto error;
718 }
719
720 chan->enabled = 1;
e1f3997a
JD
721 DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64 ")",
722 chan->channel->name, chan->fd, chan->key);
d36b8583
DG
723
724 return 0;
725
726error:
727 return ret;
728}
729
19e70852 730/*
050349bb 731 * Enable a kernel event.
19e70852
DG
732 */
733int kernel_enable_event(struct ltt_kernel_event *event)
734{
735 int ret;
736
0525e9ae
DG
737 assert(event);
738
19e70852 739 ret = kernctl_enable(event->fd);
42224349 740 if (ret < 0) {
32af2c95 741 switch (-ret) {
42224349 742 case EEXIST:
f73fabfd 743 ret = LTTNG_ERR_KERN_EVENT_EXIST;
42224349
DG
744 break;
745 default:
746 PERROR("enable kernel event");
747 break;
748 }
19e70852
DG
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
757error:
d36b8583 758 return ret;
19e70852
DG
759}
760
e953ef25 761/*
050349bb 762 * Disable a kernel event.
e953ef25 763 */
19e70852 764int kernel_disable_event(struct ltt_kernel_event *event)
e953ef25
DG
765{
766 int ret;
19e70852 767
0525e9ae
DG
768 assert(event);
769
19e70852 770 ret = kernctl_disable(event->fd);
42224349 771 if (ret < 0) {
d79bd829
JG
772 PERROR("Failed to disable kernel event: name = '%s', fd = %d",
773 event->event->name, event->fd);
19e70852 774 goto error;
e953ef25 775 }
f3ed775e 776
19e70852
DG
777 event->enabled = 0;
778 DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
779
f34daff7
DG
780 return 0;
781
782error:
d36b8583 783 return ret;
f34daff7 784}
aaf26714 785
352b58f5
JR
786/*
787 * Disable a kernel event notifier.
788 */
789static
790int 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) {
d79bd829
JG
802 PERROR("Failed to disable kernel event notifier: fd = %d, token = %" PRIu64,
803 event->fd, event->token);
352b58f5
JR
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
811error:
812 return ret;
813}
814
159b042f
JG
815static
816struct process_attr_tracker *_kernel_get_process_attr_tracker(
55c9e7ca 817 struct ltt_kernel_session *session,
159b042f 818 enum lttng_process_attr process_attr)
55c9e7ca 819{
159b042f
JG
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;
55c9e7ca
JR
833 default:
834 return NULL;
835 }
836}
6e911cad 837
159b042f 838const struct process_attr_tracker *kernel_get_process_attr_tracker(
55c9e7ca 839 struct ltt_kernel_session *session,
159b042f 840 enum lttng_process_attr process_attr)
ccf10263 841{
159b042f
JG
842 return (const struct process_attr_tracker *)
843 _kernel_get_process_attr_tracker(session, process_attr);
844}
7c493d31 845
159b042f
JG
846enum 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;
55c9e7ca 856
159b042f
JG
857 if (!tracker) {
858 ret_code = LTTNG_ERR_INVALID;
859 goto end;
7c493d31 860 }
ccf10263 861
159b042f
JG
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;
55c9e7ca 867 }
7c493d31 868
159b042f 869 if (previous_policy == policy) {
55c9e7ca 870 goto end;
7c493d31 871 }
55c9e7ca 872
159b042f
JG
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);
55c9e7ca
JR
884 }
885 break;
159b042f
JG
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);
55c9e7ca
JR
898 }
899 break;
900 default:
159b042f 901 abort();
55c9e7ca 902 }
159b042f 903 /* kern-ctl error handling */
32af2c95 904 switch (-ret) {
159b042f
JG
905 case 0:
906 ret_code = LTTNG_OK;
907 break;
7c493d31 908 case EINVAL:
159b042f 909 ret_code = LTTNG_ERR_INVALID;
55c9e7ca 910 break;
7c493d31 911 case ENOMEM:
159b042f 912 ret_code = LTTNG_ERR_NOMEM;
55c9e7ca
JR
913 break;
914 case EEXIST:
159b042f 915 ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
55c9e7ca 916 break;
7c493d31 917 default:
159b042f 918 ret_code = LTTNG_ERR_UNK;
55c9e7ca
JR
919 break;
920 }
55c9e7ca 921end:
159b042f 922 return ret_code;
ccf10263
MD
923}
924
159b042f 925enum lttng_error_code kernel_process_attr_tracker_inclusion_set_add_value(
55c9e7ca 926 struct ltt_kernel_session *session,
159b042f
JG
927 enum lttng_process_attr process_attr,
928 const struct process_attr_value *value)
a5dfbb9d 929{
159b042f
JG
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;
a5dfbb9d 934
159b042f
JG
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;
55c9e7ca 943 break;
159b042f
JG
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;
55c9e7ca
JR
957 }
958 break;
159b042f
JG
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;
a5dfbb9d 972 }
55c9e7ca
JR
973 break;
974 default:
159b042f
JG
975 ret_code = LTTNG_ERR_INVALID;
976 goto end;
55c9e7ca
JR
977 }
978
159b042f
JG
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 */
55c9e7ca 1023 switch (-ret) {
159b042f
JG
1024 case 0:
1025 ret_code = LTTNG_OK;
1026 break;
55c9e7ca 1027 case EINVAL:
159b042f 1028 ret_code = LTTNG_ERR_INVALID;
55c9e7ca
JR
1029 break;
1030 case ENOMEM:
159b042f 1031 ret_code = LTTNG_ERR_NOMEM;
55c9e7ca
JR
1032 break;
1033 case EEXIST:
159b042f 1034 ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
55c9e7ca
JR
1035 break;
1036 default:
159b042f 1037 ret_code = LTTNG_ERR_UNK;
55c9e7ca 1038 break;
a5dfbb9d
MD
1039 }
1040
159b042f
JG
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);
55c9e7ca 1048 }
a5dfbb9d 1049end:
159b042f 1050 return ret_code;
55c9e7ca 1051}
a5dfbb9d 1052
159b042f 1053enum lttng_error_code kernel_process_attr_tracker_inclusion_set_remove_value(
55c9e7ca 1054 struct ltt_kernel_session *session,
159b042f
JG
1055 enum lttng_process_attr process_attr,
1056 const struct process_attr_value *value)
55c9e7ca 1057{
159b042f
JG
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 }
55c9e7ca 1106
159b042f
JG
1107 tracker = _kernel_get_process_attr_tracker(session, process_attr);
1108 if (!tracker) {
1109 ret_code = LTTNG_ERR_INVALID;
a7a533cd 1110 goto end;
a5dfbb9d 1111 }
a7a533cd 1112
159b042f
JG
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 }
a7a533cd
JR
1128 goto end;
1129 }
1130
159b042f
JG
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 }
a7a533cd 1177end:
159b042f 1178 return ret_code;
a5dfbb9d
MD
1179}
1180
aaf26714 1181/*
050349bb
DG
1182 * Create kernel metadata, open from the kernel tracer and add it to the
1183 * kernel session.
aaf26714 1184 */
a4b92340 1185int kernel_open_metadata(struct ltt_kernel_session *session)
aaf26714
DG
1186{
1187 int ret;
74024a21 1188 struct ltt_kernel_metadata *lkm = NULL;
aaf26714 1189
0525e9ae
DG
1190 assert(session);
1191
54012638 1192 /* Allocate kernel metadata */
a4b92340 1193 lkm = trace_kernel_create_metadata();
54012638 1194 if (lkm == NULL) {
aaf26714
DG
1195 goto error;
1196 }
1197
54012638 1198 /* Kernel tracer metadata creation */
f3ed775e 1199 ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
aaf26714 1200 if (ret < 0) {
74024a21 1201 goto error_open;
aaf26714
DG
1202 }
1203
8c0faa1d 1204 lkm->fd = ret;
d40f0359 1205 lkm->key = ++next_kernel_channel_key;
7b395890
DG
1206 /* Prevent fd duplication after execlp() */
1207 ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
1208 if (ret < 0) {
df0f840b 1209 PERROR("fcntl session fd");
7b395890
DG
1210 }
1211
aaf26714 1212 session->metadata = lkm;
8c0faa1d 1213
00e2e675 1214 DBG("Kernel metadata opened (fd: %d)", lkm->fd);
8c0faa1d
DG
1215
1216 return 0;
1217
74024a21
DG
1218error_open:
1219 trace_kernel_destroy_metadata(lkm);
8c0faa1d 1220error:
54012638 1221 return -1;
8c0faa1d
DG
1222}
1223
1224/*
050349bb 1225 * Start tracing session.
8c0faa1d
DG
1226 */
1227int kernel_start_session(struct ltt_kernel_session *session)
1228{
1229 int ret;
1230
0525e9ae
DG
1231 assert(session);
1232
8c0faa1d
DG
1233 ret = kernctl_start_session(session->fd);
1234 if (ret < 0) {
df0f840b 1235 PERROR("ioctl start session");
8c0faa1d
DG
1236 goto error;
1237 }
1238
1239 DBG("Kernel session started");
1240
1241 return 0;
1242
1243error:
1244 return ret;
1245}
1246
f3ed775e 1247/*
050349bb 1248 * Make a kernel wait to make sure in-flight probe have completed.
f3ed775e 1249 */
7d268848 1250void kernel_wait_quiescent(void)
f3ed775e
DG
1251{
1252 int ret;
7d268848 1253 int fd = kernel_tracer_fd;
f3ed775e
DG
1254
1255 DBG("Kernel quiescent wait on %d", fd);
1256
1257 ret = kernctl_wait_quiescent(fd);
1258 if (ret < 0) {
df0f840b 1259 PERROR("wait quiescent ioctl");
f3ed775e
DG
1260 ERR("Kernel quiescent wait failed");
1261 }
1262}
1263
1264/*
f3ed775e
DG
1265 * Force flush buffer of metadata.
1266 */
1267int kernel_metadata_flush_buffer(int fd)
1268{
1269 int ret;
1270
169d2cb7
DG
1271 DBG("Kernel flushing metadata buffer on fd %d", fd);
1272
f3ed775e
DG
1273 ret = kernctl_buffer_flush(fd);
1274 if (ret < 0) {
00e2e675 1275 ERR("Fail to flush metadata buffers %d (ret: %d)", fd, ret);
f3ed775e
DG
1276 }
1277
1278 return 0;
1279}
1280
1281/*
050349bb 1282 * Force flush buffer for channel.
f3ed775e
DG
1283 */
1284int kernel_flush_buffer(struct ltt_kernel_channel *channel)
1285{
1286 int ret;
1287 struct ltt_kernel_stream *stream;
1288
0525e9ae
DG
1289 assert(channel);
1290
f3ed775e
DG
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) {
df0f840b 1297 PERROR("ioctl");
f3ed775e
DG
1298 ERR("Fail to flush buffer for stream %d (ret: %d)",
1299 stream->fd, ret);
1300 }
1301 }
1302
1303 return 0;
1304}
1305
8c0faa1d 1306/*
050349bb 1307 * Stop tracing session.
8c0faa1d
DG
1308 */
1309int kernel_stop_session(struct ltt_kernel_session *session)
1310{
1311 int ret;
1312
0525e9ae
DG
1313 assert(session);
1314
8c0faa1d
DG
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
1324error:
1325 return ret;
1326}
1327
1328/*
050349bb
DG
1329 * Open stream of channel, register it to the kernel tracer and add it
1330 * to the stream list of the channel.
8c0faa1d 1331 *
1cfb4b98
MD
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 *
050349bb 1336 * Return the number of created stream. Else, a negative value.
8c0faa1d 1337 */
f3ed775e 1338int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
8c0faa1d 1339{
1cfb4b98 1340 int ret;
8c0faa1d
DG
1341 struct ltt_kernel_stream *lks;
1342
0525e9ae
DG
1343 assert(channel);
1344
5a47c6a2 1345 while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
1cfb4b98
MD
1346 lks = trace_kernel_create_stream(channel->channel->name,
1347 channel->stream_count);
8c0faa1d 1348 if (lks == NULL) {
799e2c4f
MD
1349 ret = close(ret);
1350 if (ret) {
1351 PERROR("close");
1352 }
8c0faa1d
DG
1353 goto error;
1354 }
1355
1356 lks->fd = ret;
7b395890
DG
1357 /* Prevent fd duplication after execlp() */
1358 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
1359 if (ret < 0) {
df0f840b 1360 PERROR("fcntl session fd");
7b395890
DG
1361 }
1362
1624d5b7
JD
1363 lks->tracefile_size = channel->channel->attr.tracefile_size;
1364 lks->tracefile_count = channel->channel->attr.tracefile_count;
1365
1cfb4b98 1366 /* Add stream to channel stream list */
8c0faa1d
DG
1367 cds_list_add(&lks->list, &channel->stream_list.head);
1368 channel->stream_count++;
8c0faa1d 1369
00e2e675
DG
1370 DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd,
1371 lks->state);
54012638 1372 }
8c0faa1d
DG
1373
1374 return channel->stream_count;
1375
1376error:
54012638 1377 return -1;
8c0faa1d
DG
1378}
1379
1380/*
050349bb 1381 * Open the metadata stream and set it to the kernel session.
8c0faa1d 1382 */
f3ed775e 1383int kernel_open_metadata_stream(struct ltt_kernel_session *session)
8c0faa1d
DG
1384{
1385 int ret;
1386
0525e9ae
DG
1387 assert(session);
1388
8c0faa1d
DG
1389 ret = kernctl_create_stream(session->metadata->fd);
1390 if (ret < 0) {
df0f840b 1391 PERROR("kernel create metadata stream");
8c0faa1d
DG
1392 goto error;
1393 }
1394
1395 DBG("Kernel metadata stream created (fd: %d)", ret);
1396 session->metadata_stream_fd = ret;
7b395890
DG
1397 /* Prevent fd duplication after execlp() */
1398 ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
1399 if (ret < 0) {
df0f840b 1400 PERROR("fcntl session fd");
7b395890 1401 }
aaf26714
DG
1402
1403 return 0;
1404
1405error:
54012638 1406 return -1;
aaf26714 1407}
2ef84c95
DG
1408
1409/*
9f19cc17 1410 * Get the event list from the kernel tracer and return the number of elements.
2ef84c95 1411 */
7d268848 1412ssize_t kernel_list_events(struct lttng_event **events)
2ef84c95 1413{
53efb85a 1414 int fd, ret;
9f19cc17
DG
1415 char *event;
1416 size_t nbmem, count = 0;
2ef84c95 1417 FILE *fp;
9f19cc17 1418 struct lttng_event *elist;
2ef84c95 1419
0525e9ae
DG
1420 assert(events);
1421
7d268848 1422 fd = kernctl_tracepoint_list(kernel_tracer_fd);
2ef84c95 1423 if (fd < 0) {
df0f840b 1424 PERROR("kernel tracepoint list");
2ef84c95
DG
1425 goto error;
1426 }
1427
1428 fp = fdopen(fd, "r");
1429 if (fp == NULL) {
df0f840b 1430 PERROR("kernel tracepoint list fdopen");
61b73b12 1431 goto error_fp;
2ef84c95
DG
1432 }
1433
1434 /*
1435 * Init memory size counter
1436 * See kernel-ctl.h for explanation of this value
1437 */
6725fe19 1438 nbmem = KERNEL_EVENT_INIT_LIST_SIZE;
ba7f0ae5 1439 elist = zmalloc(sizeof(struct lttng_event) * nbmem);
3b870559
MD
1440 if (elist == NULL) {
1441 PERROR("alloc list events");
1442 count = -ENOMEM;
1443 goto end;
1444 }
2ef84c95 1445
53efb85a 1446 while (fscanf(fp, "event { name = %m[^;]; };\n", &event) == 1) {
6725fe19 1447 if (count >= nbmem) {
3b870559 1448 struct lttng_event *new_elist;
53efb85a 1449 size_t new_nbmem;
3b870559 1450
53efb85a
MD
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));
3b870559 1455 if (new_elist == NULL) {
df0f840b 1456 PERROR("realloc list events");
3b870559
MD
1457 free(event);
1458 free(elist);
61b73b12
MD
1459 count = -ENOMEM;
1460 goto end;
2ef84c95 1461 }
53efb85a
MD
1462 /* Zero the new memory */
1463 memset(new_elist + nbmem, 0,
1464 (new_nbmem - nbmem) * sizeof(struct lttng_event));
1465 nbmem = new_nbmem;
3b870559 1466 elist = new_elist;
2ef84c95 1467 }
99497cd0
MD
1468 strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
1469 elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
67b9d018 1470 elist[count].enabled = -1;
9f19cc17 1471 count++;
3b870559 1472 free(event);
2ef84c95
DG
1473 }
1474
9f19cc17 1475 *events = elist;
ced2f820 1476 DBG("Kernel list events done (%zu events)", count);
61b73b12 1477end:
799e2c4f
MD
1478 ret = fclose(fp); /* closes both fp and fd */
1479 if (ret) {
1480 PERROR("fclose");
1481 }
9f19cc17 1482 return count;
2ef84c95 1483
61b73b12 1484error_fp:
799e2c4f
MD
1485 ret = close(fd);
1486 if (ret) {
1487 PERROR("close");
1488 }
2ef84c95
DG
1489error:
1490 return -1;
1491}
096102bd
DG
1492
1493/*
1494 * Get kernel version and validate it.
1495 */
7d268848 1496int kernel_validate_version(struct lttng_kernel_tracer_version *version,
88076e89 1497 struct lttng_kernel_tracer_abi_version *abi_version)
096102bd
DG
1498{
1499 int ret;
096102bd 1500
7d268848 1501 ret = kernctl_tracer_version(kernel_tracer_fd, version);
096102bd 1502 if (ret < 0) {
521dd134 1503 ERR("Failed to retrieve the lttng-modules version");
096102bd
DG
1504 goto error;
1505 }
1506
1507 /* Validate version */
88076e89 1508 if (version->major != VERSION_MAJOR) {
c052142c 1509 ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
88076e89 1510 version->major, VERSION_MAJOR);
096102bd 1511 goto error_version;
096102bd 1512 }
7d268848 1513 ret = kernctl_tracer_abi_version(kernel_tracer_fd, abi_version);
c052142c 1514 if (ret < 0) {
521dd134 1515 ERR("Failed to retrieve lttng-modules ABI version");
c052142c
MD
1516 goto error;
1517 }
88076e89 1518 if (abi_version->major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
521dd134 1519 ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
88076e89 1520 abi_version->major, abi_version->minor,
c052142c
MD
1521 LTTNG_MODULES_ABI_MAJOR_VERSION);
1522 goto error;
1523 }
1524 DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
88076e89
JD
1525 version->major, version->minor,
1526 abi_version->major, abi_version->minor);
096102bd
DG
1527 return 0;
1528
1529error_version:
096102bd
DG
1530 ret = -1;
1531
1532error:
521dd134 1533 ERR("Kernel tracer version check failed; kernel tracing will not be available");
096102bd
DG
1534 return ret;
1535}
335a95b7
MD
1536
1537/*
1538 * Kernel work-arounds called at the start of sessiond main().
1539 */
1540int init_kernel_workarounds(void)
1541{
8936c33a 1542 int ret;
335a95b7
MD
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
8936c33a
DG
1557 ret = fread(buf, 1, sizeof(buf), fp);
1558 if (ret < 0) {
1559 /* Ignore error, we don't really care */
1560 }
335a95b7 1561 }
799e2c4f
MD
1562 ret = fclose(fp);
1563 if (ret) {
1564 PERROR("fclose");
1565 }
335a95b7 1566end_boot_id:
335a95b7
MD
1567 return 0;
1568}
2f77fc4b
DG
1569
1570/*
d070c424 1571 * Teardown of a kernel session, keeping data required by destroy notifiers.
2f77fc4b
DG
1572 */
1573void kernel_destroy_session(struct ltt_kernel_session *ksess)
1574{
82b69413
JG
1575 struct lttng_trace_chunk *trace_chunk;
1576
2f77fc4b
DG
1577 if (ksess == NULL) {
1578 DBG3("No kernel session when tearing down session");
1579 return;
1580 }
1581
1582 DBG("Tearing down kernel session");
82b69413 1583 trace_chunk = ksess->current_trace_chunk;
2f77fc4b 1584
07b86b52 1585 /*
15dc512a
DG
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.
07b86b52 1589 */
15dc512a 1590 if (!ksess->output_traces && ksess->consumer_fds_sent) {
07b86b52
JD
1591 int ret;
1592 struct consumer_socket *socket;
1593 struct lttng_ht_iter iter;
1594
1595 /* For each consumer socket. */
d069d577 1596 rcu_read_lock();
07b86b52
JD
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 }
d069d577 1610 rcu_read_unlock();
07b86b52
JD
1611 }
1612
2f77fc4b
DG
1613 /* Close any relayd session */
1614 consumer_output_send_destroy_relayd(ksess->consumer);
1615
1616 trace_kernel_destroy_session(ksess);
82b69413 1617 lttng_trace_chunk_put(trace_chunk);
2f77fc4b 1618}
fb5f35b6 1619
d070c424
MD
1620/* Teardown of data required by destroy notifiers. */
1621void kernel_free_session(struct ltt_kernel_session *ksess)
1622{
1623 if (ksess == NULL) {
1624 return;
1625 }
1626 trace_kernel_free_session(ksess);
1627}
1628
fb5f35b6
DG
1629/*
1630 * Destroy a kernel channel object. It does not do anything on the tracer side.
1631 */
1632void 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}
6dc3064a
DG
1658
1659/*
1660 * Take a snapshot for a given kernel session.
1661 *
9a654598 1662 * Return LTTNG_OK on success or else return a LTTNG_ERR code.
6dc3064a 1663 */
fb9a95c4
JG
1664enum lttng_error_code kernel_snapshot_record(
1665 struct ltt_kernel_session *ksess,
348a81dc 1666 const struct consumer_output *output, int wait,
d07ceecd 1667 uint64_t nb_packets_per_stream)
6dc3064a 1668{
2a06df8d 1669 int err, ret, saved_metadata_fd;
9a654598 1670 enum lttng_error_code status = LTTNG_OK;
6dc3064a
DG
1671 struct consumer_socket *socket;
1672 struct lttng_ht_iter iter;
1673 struct ltt_kernel_metadata *saved_metadata;
3b967712 1674 char *trace_path = NULL;
5da88b0f 1675 size_t consumer_path_offset = 0;
6dc3064a
DG
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) {
9a654598 1691 status = LTTNG_ERR_KERN_META_FAIL;
6dc3064a
DG
1692 goto error;
1693 }
1694
1695 ret = kernel_open_metadata_stream(ksess);
1696 if (ret < 0) {
9a654598 1697 status = LTTNG_ERR_KERN_META_FAIL;
6dc3064a
DG
1698 goto error_open_stream;
1699 }
1700
3b967712 1701 trace_path = setup_channel_trace_path(ksess->consumer,
5da88b0f 1702 DEFAULT_KERNEL_TRACE_DIR, &consumer_path_offset);
3b967712
MD
1703 if (!trace_path) {
1704 status = LTTNG_ERR_INVALID;
1705 goto error;
1706 }
6dc3064a 1707 /* Send metadata to consumer and snapshot everything. */
348a81dc 1708 cds_lfht_for_each_entry(output->socks->ht, &iter.iter,
6dc3064a 1709 socket, node.node) {
6dc3064a 1710 struct ltt_kernel_channel *chan;
6dc3064a 1711
6dc3064a
DG
1712 pthread_mutex_lock(socket->lock);
1713 /* This stream must not be monitored by the consumer. */
07b86b52 1714 ret = kernel_consumer_add_metadata(socket, ksess, 0);
6dc3064a 1715 pthread_mutex_unlock(socket->lock);
6dc3064a 1716 if (ret < 0) {
0ed78e50 1717 status = LTTNG_ERR_KERN_META_FAIL;
6dc3064a
DG
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) {
9a654598 1723 status = consumer_snapshot_channel(socket, chan->key, output, 0,
5c786ded 1724 ksess->uid, ksess->gid,
5da88b0f 1725 &trace_path[consumer_path_offset], wait,
d2956687 1726 nb_packets_per_stream);
9a654598 1727 if (status != LTTNG_OK) {
2a06df8d
DG
1728 (void) kernel_consumer_destroy_metadata(socket,
1729 ksess->metadata);
6dc3064a
DG
1730 goto error_consumer;
1731 }
1732 }
1733
1734 /* Snapshot metadata, */
9a654598 1735 status = consumer_snapshot_channel(socket, ksess->metadata->key, output,
5da88b0f
MD
1736 1, ksess->uid, ksess->gid, &trace_path[consumer_path_offset],
1737 wait, 0);
9a654598 1738 if (status != LTTNG_OK) {
6dc3064a
DG
1739 goto error_consumer;
1740 }
07b86b52
JD
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);
6dc3064a
DG
1747 }
1748
1749error_consumer:
1750 /* Close newly opened metadata stream. It's now on the consumer side. */
2a06df8d
DG
1751 err = close(ksess->metadata_stream_fd);
1752 if (err < 0) {
6dc3064a
DG
1753 PERROR("close snapshot kernel");
1754 }
1755
1756error_open_stream:
1757 trace_kernel_destroy_metadata(ksess->metadata);
1758error:
1759 /* Restore metadata state.*/
1760 ksess->metadata = saved_metadata;
1761 ksess->metadata_stream_fd = saved_metadata_fd;
6dc3064a 1762 rcu_read_unlock();
3b967712 1763 free(trace_path);
9a654598 1764 return status;
6dc3064a 1765}
834978fd
DG
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 */
1773int 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}
6e21424e 1780
959e3c66
JR
1781static
1782int kernel_tracer_abi_greater_or_equal(unsigned int major, unsigned int minor)
6e21424e 1783{
959e3c66 1784 int ret;
6e21424e
JR
1785 struct lttng_kernel_tracer_abi_version abi;
1786
7d268848 1787 ret = kernctl_tracer_abi_version(kernel_tracer_fd, &abi);
6e21424e
JR
1788 if (ret < 0) {
1789 ERR("Failed to retrieve lttng-modules ABI version");
1790 goto error;
1791 }
1792
959e3c66
JR
1793 ret = abi.major > major || (abi.major == major && abi.minor >= minor);
1794error:
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 */
1805int kernel_supports_ring_buffer_snapshot_sample_positions(void)
1806{
6e21424e
JR
1807 /*
1808 * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3
1809 */
959e3c66 1810 return kernel_tracer_abi_greater_or_equal(2, 3);
6e21424e 1811}
5c408ad8 1812
a40a503f
MD
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 */
1819int kernel_supports_ring_buffer_packet_sequence_number(void)
1820{
a40a503f 1821 /*
3029bc92
JG
1822 * Packet sequence number was introduced in LTTng 2.8,
1823 * lttng-modules ABI 2.1.
a40a503f 1824 */
959e3c66
JR
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 */
1834int 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);
a40a503f
MD
1840}
1841
5c408ad8
JD
1842/*
1843 * Rotate a kernel session.
1844 *
d5a1b7aa 1845 * Return LTTNG_OK on success or else an LTTng error code.
5c408ad8 1846 */
d5a1b7aa 1847enum lttng_error_code kernel_rotate_session(struct ltt_session *session)
5c408ad8
JD
1848{
1849 int ret;
d5a1b7aa 1850 enum lttng_error_code status = LTTNG_OK;
5c408ad8
JD
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
b8a1b0bd 1871 /* For each channel, ask the consumer to rotate it. */
5c408ad8 1872 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
92816cc3
JG
1873 DBG("Rotate kernel channel %" PRIu64 ", session %s",
1874 chan->key, session->name);
5c408ad8
JD
1875 ret = consumer_rotate_channel(socket, chan->key,
1876 ksess->uid, ksess->gid, ksess->consumer,
d2956687 1877 /* is_metadata_channel */ false);
5c408ad8 1878 if (ret < 0) {
7e0de219 1879 status = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
5c408ad8
JD
1880 goto error;
1881 }
1882 }
1883
1884 /*
1885 * Rotate the metadata channel.
1886 */
22a1b931 1887 ret = consumer_rotate_channel(socket, ksess->metadata->key,
5c408ad8 1888 ksess->uid, ksess->gid, ksess->consumer,
d2956687 1889 /* is_metadata_channel */ true);
5c408ad8 1890 if (ret < 0) {
7e0de219 1891 status = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
5c408ad8
JD
1892 goto error;
1893 }
1894 }
1895
5c408ad8
JD
1896error:
1897 rcu_read_unlock();
d5a1b7aa 1898 return status;
5c408ad8 1899}
d2956687
JG
1900
1901enum 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 }
1921error:
1922 rcu_read_unlock();
1923 return ret;
1924}
7d268848
MD
1925
1926/*
1927 * Setup necessary data for kernel tracer action.
1928 */
1929LTTNG_HIDDEN
1930int 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 }
7d268848
MD
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
352b58f5
JR
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 {
90aa04a1
FD
1981 enum event_notifier_error_accounting_status error_accounting_status;
1982 enum lttng_error_code error_code_ret =
352b58f5
JR
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
90aa04a1
FD
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
352b58f5
JR
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);
7d268848
MD
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 }
352b58f5 2016
7d268848
MD
2017 return 0;
2018
2019error_version:
2020 modprobe_remove_lttng_control();
2021 ret = close(kernel_tracer_fd);
2022 if (ret) {
352b58f5
JR
2023 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2024 kernel_tracer_fd);
7d268848 2025 }
6dcf80d3 2026
7d268848
MD
2027 kernel_tracer_fd = -1;
2028 return LTTNG_ERR_KERN_VERSION;
2029
352b58f5
JR
2030
2031error_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
6dcf80d3
JG
2038 kernel_tracer_event_notifier_group_notification_fd = -1;
2039
7d268848 2040error_modules:
352b58f5
JR
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
6dcf80d3
JG
2047 kernel_tracer_event_notifier_group_fd = -1;
2048
7d268848
MD
2049 ret = close(kernel_tracer_fd);
2050 if (ret) {
352b58f5
JR
2051 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2052 kernel_tracer_fd);
7d268848
MD
2053 }
2054
6dcf80d3
JG
2055 kernel_tracer_fd = -1;
2056
7d268848
MD
2057error_open:
2058 modprobe_remove_lttng_control();
2059
2060error:
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
2070LTTNG_HIDDEN
2071void cleanup_kernel_tracer(void)
2072{
352b58f5
JR
2073 DBG2("Closing kernel event notifier group notification file descriptor");
2074 if (kernel_tracer_event_notifier_group_notification_fd >= 0) {
b69a1b40 2075 int ret = notification_thread_command_remove_tracer_event_source(
352b58f5
JR
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) {
b69a1b40
JG
2092 const int ret = cds_lfht_destroy(
2093 kernel_token_to_event_notifier_rule_ht, NULL);
352b58f5
JR
2094 assert(ret == 0);
2095 }
2096
2097 DBG2("Closing kernel event notifier group file descriptor");
2098 if (kernel_tracer_event_notifier_group_fd >= 0) {
b69a1b40
JG
2099 const int ret = close(kernel_tracer_event_notifier_group_fd);
2100
352b58f5
JR
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 }
7d268848
MD
2108
2109 DBG2("Closing kernel fd");
2110 if (kernel_tracer_fd >= 0) {
b69a1b40
JG
2111 const int ret = close(kernel_tracer_fd);
2112
7d268848 2113 if (ret) {
352b58f5
JR
2114 PERROR("Failed to close kernel tracer file descriptor: fd = %d",
2115 kernel_tracer_fd);
7d268848 2116 }
352b58f5 2117
7d268848
MD
2118 kernel_tracer_fd = -1;
2119 }
352b58f5 2120
7d268848
MD
2121 free(syscall_table);
2122}
2123
2124LTTNG_HIDDEN
2125bool kernel_tracer_is_initialized(void)
2126{
2127 return kernel_tracer_fd >= 0;
2128}
bca212a2
MD
2129
2130/*
2131 * Clear a kernel session.
2132 *
2133 * Return LTTNG_OK on success or else an LTTng error code.
2134 */
2135enum 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;
2196error:
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 }
2205end:
2206 rcu_read_unlock();
2207 return status;
2208}
352b58f5
JR
2209
2210enum 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
2243error:
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
2255enum 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
2273static
2274unsigned 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
2282static
2283int 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
2294static 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 = {};
bbd6675c 2305 unsigned int capture_bytecode_count = 0, i;
352b58f5
JR
2306 const struct lttng_condition *condition = NULL;
2307 const struct lttng_event_rule *event_rule = NULL;
bbd6675c 2308 enum lttng_condition_status cond_status;
352b58f5
JR
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);
d602bd6a 2316 assert(condition_type == LTTNG_CONDITION_TYPE_ON_EVENT);
352b58f5
JR
2317
2318 /* Does not acquire a reference. */
d602bd6a 2319 condition_status = lttng_condition_on_event_get_rule(
352b58f5
JR
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,
90aa04a1 2328 lttng_condition_on_event_get_error_counter_index(condition),
352b58f5
JR
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) {
b5e3b044 2337 goto free_event;
352b58f5
JR
2338 }
2339
2340 kernel_event_notifier.event.token = event_notifier_rule->token;
90aa04a1
FD
2341 kernel_event_notifier.error_counter_idx =
2342 lttng_condition_on_event_get_error_counter_index(condition);
352b58f5
JR
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) ==
1f1567a5 2395 LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE) {
352b58f5
JR
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
d602bd6a
JR
2404 /* Set the capture bytecode if any. */
2405 cond_status = lttng_condition_on_event_get_capture_descriptor_count(
bbd6675c
JR
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 =
d602bd6a 2411 lttng_condition_on_event_get_capture_bytecode_at_index(
bbd6675c
JR
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;
e8b1187d 2417 goto capture_error;
bbd6675c
JR
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;
e8b1187d 2425 goto capture_error;
bbd6675c
JR
2426 }
2427 }
2428
352b58f5
JR
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
e8b1187d 2455capture_error:
352b58f5
JR
2456add_callsite_error:
2457enable_error:
2458set_cloexec_error:
2459filter_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 }
2468free_event:
2469 free(event_notifier_rule);
2470error:
2471 return error_code_ret;
2472}
2473
2474enum 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. */
d602bd6a 2489 status = lttng_condition_on_event_get_rule(
352b58f5
JR
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) {
124dda43 2498 ERR("Failed to create kernel event notifier rule");
352b58f5
JR
2499 }
2500
2501 return ret;
2502}
2503
2504enum 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
2536error:
2537 rcu_read_unlock();
2538
2539 return error_code_ret;
2540}
2541
2542int kernel_get_notification_fd(void)
2543{
2544 return kernel_tracer_event_notifier_group_notification_fd;
2545}
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