Implement UST PID tracker
[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c
CommitLineData
20fe2104
DG
1/*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
d14d33bf
AM
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
20fe2104
DG
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
d14d33bf
AM
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20fe2104
DG
16 */
17
8c0faa1d 18#define _GNU_SOURCE
6c1c0768 19#define _LGPL_SOURCE
20fe2104 20#include <errno.h>
7b395890 21#include <fcntl.h>
20fe2104
DG
22#include <stdlib.h>
23#include <stdio.h>
f34daff7 24#include <string.h>
8c0faa1d 25#include <unistd.h>
77c7c900 26#include <inttypes.h>
20fe2104 27
990570ed 28#include <common/common.h>
db758600 29#include <common/kernel-ctl/kernel-ctl.h>
c052142c 30#include <common/kernel-ctl/kernel-ioctl.h>
42224349 31#include <common/sessiond-comm/sessiond-comm.h>
1e307fab 32
2f77fc4b 33#include "consumer.h"
4771f025 34#include "kernel.h"
6dc3064a 35#include "kernel-consumer.h"
096102bd 36#include "kern-modules.h"
834978fd 37#include "utils.h"
20fe2104 38
d65106b1 39/*
050349bb 40 * Add context on a kernel channel.
d65106b1
DG
41 */
42int kernel_add_channel_context(struct ltt_kernel_channel *chan,
645328ae 43 struct ltt_kernel_context *ctx)
d65106b1
DG
44{
45 int ret;
46
0525e9ae
DG
47 assert(chan);
48 assert(ctx);
49
d65106b1 50 DBG("Adding context to channel %s", chan->channel->name);
645328ae 51 ret = kernctl_add_context(chan->fd, &ctx->ctx);
d65106b1 52 if (ret < 0) {
b579acd9 53 if (errno != EEXIST) {
df0f840b 54 PERROR("add context ioctl");
b579acd9
DG
55 } else {
56 /* If EEXIST, we just ignore the error */
57 ret = 0;
58 }
d65106b1
DG
59 goto error;
60 }
61
645328ae 62 cds_list_add_tail(&ctx->list, &chan->ctx_list);
d65106b1
DG
63
64 return 0;
65
66error:
67 return ret;
68}
69
20fe2104 70/*
050349bb
DG
71 * Create a new kernel session, register it to the kernel tracer and add it to
72 * the session daemon session.
20fe2104 73 */
8c0faa1d 74int kernel_create_session(struct ltt_session *session, int tracer_fd)
20fe2104
DG
75{
76 int ret;
77 struct ltt_kernel_session *lks;
78
0525e9ae
DG
79 assert(session);
80
54012638 81 /* Allocate data structure */
dec56f6c 82 lks = trace_kernel_create_session();
20fe2104 83 if (lks == NULL) {
54012638 84 ret = -1;
20fe2104
DG
85 goto error;
86 }
87
54012638 88 /* Kernel tracer session creation */
20fe2104
DG
89 ret = kernctl_create_session(tracer_fd);
90 if (ret < 0) {
df0f840b 91 PERROR("ioctl kernel create session");
20fe2104
DG
92 goto error;
93 }
94
20fe2104 95 lks->fd = ret;
7b395890
DG
96 /* Prevent fd duplication after execlp() */
97 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
98 if (ret < 0) {
df0f840b 99 PERROR("fcntl session fd");
7b395890
DG
100 }
101
53632229 102 lks->id = session->id;
3bd1e081 103 lks->consumer_fds_sent = 0;
8c0faa1d 104 session->kernel_session = lks;
8c0faa1d
DG
105
106 DBG("Kernel session created (fd: %d)", lks->fd);
20fe2104
DG
107
108 return 0;
109
110error:
5f62c685
DG
111 if (lks) {
112 trace_kernel_destroy_session(lks);
113 }
20fe2104
DG
114 return ret;
115}
116
117/*
050349bb
DG
118 * Create a kernel channel, register it to the kernel tracer and add it to the
119 * kernel session.
20fe2104 120 */
050349bb 121int kernel_create_channel(struct ltt_kernel_session *session,
fdd9eb17 122 struct lttng_channel *chan)
20fe2104
DG
123{
124 int ret;
125 struct ltt_kernel_channel *lkc;
20fe2104 126
0525e9ae
DG
127 assert(session);
128 assert(chan);
0525e9ae 129
54012638 130 /* Allocate kernel channel */
fdd9eb17 131 lkc = trace_kernel_create_channel(chan);
54012638 132 if (lkc == NULL) {
20fe2104
DG
133 goto error;
134 }
135
ecc48a90 136 DBG3("Kernel create channel %s with attr: %d, %" PRIu64 ", %" PRIu64 ", %u, %u, %d, %d",
fdd9eb17 137 chan->name, lkc->channel->attr.overwrite,
173af62f
DG
138 lkc->channel->attr.subbuf_size, lkc->channel->attr.num_subbuf,
139 lkc->channel->attr.switch_timer_interval, lkc->channel->attr.read_timer_interval,
ecc48a90 140 lkc->channel->attr.live_timer_interval, lkc->channel->attr.output);
173af62f 141
54012638 142 /* Kernel tracer channel creation */
f3ed775e 143 ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
20fe2104 144 if (ret < 0) {
df0f840b 145 PERROR("ioctl kernel create channel");
20fe2104
DG
146 goto error;
147 }
148
54012638 149 /* Setup the channel fd */
20fe2104 150 lkc->fd = ret;
7b395890
DG
151 /* Prevent fd duplication after execlp() */
152 ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
153 if (ret < 0) {
df0f840b 154 PERROR("fcntl session fd");
7b395890
DG
155 }
156
54012638 157 /* Add channel to session */
8c0faa1d
DG
158 cds_list_add(&lkc->list, &session->channel_list.head);
159 session->channel_count++;
fb5f35b6 160 lkc->session = session;
20fe2104 161
00e2e675 162 DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd);
20fe2104
DG
163
164 return 0;
165
166error:
5f62c685
DG
167 if (lkc) {
168 free(lkc->channel);
169 free(lkc);
170 }
54012638 171 return -1;
20fe2104 172}
f34daff7
DG
173
174/*
050349bb
DG
175 * Create a kernel event, enable it to the kernel tracer and add it to the
176 * channel event list of the kernel session.
49d21f93 177 * We own filter_expression and filter.
f34daff7 178 */
050349bb
DG
179int kernel_create_event(struct lttng_event *ev,
180 struct ltt_kernel_channel *channel)
f34daff7
DG
181{
182 int ret;
183 struct ltt_kernel_event *event;
f34daff7 184
0525e9ae
DG
185 assert(ev);
186 assert(channel);
187
62499ad6 188 event = trace_kernel_create_event(ev);
54012638 189 if (event == NULL) {
d87bfb32 190 ret = -1;
f34daff7
DG
191 goto error;
192 }
193
f3ed775e
DG
194 ret = kernctl_create_event(channel->fd, event->event);
195 if (ret < 0) {
bd29c13d
DG
196 switch (errno) {
197 case EEXIST:
198 break;
199 case ENOSYS:
200 WARN("Event type not implemented");
201 break;
8197a339
DG
202 case ENOENT:
203 WARN("Event %s not found!", ev->name);
204 break;
bd29c13d 205 default:
d87bfb32
DG
206 PERROR("create event ioctl");
207 }
208 ret = -errno;
e953ef25 209 goto free_event;
8c0faa1d 210 }
f34daff7 211
5f822d0a 212 /*
2c425ff7 213 * LTTNG_KERNEL_SYSCALL event creation will return 0 on success.
5f822d0a
DG
214 */
215 if (ret == 0 && event->event->instrumentation == LTTNG_KERNEL_SYSCALL) {
216 DBG2("Kernel event syscall creation success");
87eb4ab8
MD
217 /*
218 * We use fd == -1 to ensure that we never trigger a close of fd
219 * 0.
220 */
221 event->fd = -1;
2c425ff7 222 goto add_list;
5f822d0a
DG
223 }
224
f3ed775e 225 event->fd = ret;
7b395890
DG
226 /* Prevent fd duplication after execlp() */
227 ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
228 if (ret < 0) {
df0f840b 229 PERROR("fcntl session fd");
7b395890
DG
230 }
231
2c425ff7 232add_list:
f3ed775e
DG
233 /* Add event to event list */
234 cds_list_add(&event->list, &channel->events_list.head);
cbbbb275
DG
235 channel->event_count++;
236
e953ef25
DG
237 DBG("Event %s created (fd: %d)", ev->name, event->fd);
238
239 return 0;
240
241free_event:
242 free(event);
243error:
d87bfb32 244 return ret;
e953ef25
DG
245}
246
26cc6b4e 247/*
050349bb 248 * Disable a kernel channel.
26cc6b4e
DG
249 */
250int kernel_disable_channel(struct ltt_kernel_channel *chan)
251{
252 int ret;
253
0525e9ae
DG
254 assert(chan);
255
26cc6b4e
DG
256 ret = kernctl_disable(chan->fd);
257 if (ret < 0) {
df0f840b 258 PERROR("disable chan ioctl");
26cc6b4e
DG
259 ret = errno;
260 goto error;
261 }
262
263 chan->enabled = 0;
264 DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
265
266 return 0;
267
268error:
269 return ret;
270}
271
d36b8583 272/*
050349bb 273 * Enable a kernel channel.
d36b8583
DG
274 */
275int kernel_enable_channel(struct ltt_kernel_channel *chan)
276{
277 int ret;
278
0525e9ae
DG
279 assert(chan);
280
d36b8583 281 ret = kernctl_enable(chan->fd);
54d01ffb 282 if (ret < 0 && errno != EEXIST) {
df0f840b 283 PERROR("Enable kernel chan");
d36b8583
DG
284 goto error;
285 }
286
287 chan->enabled = 1;
288 DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
289
290 return 0;
291
292error:
293 return ret;
294}
295
19e70852 296/*
050349bb 297 * Enable a kernel event.
19e70852
DG
298 */
299int kernel_enable_event(struct ltt_kernel_event *event)
300{
301 int ret;
302
0525e9ae
DG
303 assert(event);
304
19e70852 305 ret = kernctl_enable(event->fd);
42224349
DG
306 if (ret < 0) {
307 switch (errno) {
308 case EEXIST:
f73fabfd 309 ret = LTTNG_ERR_KERN_EVENT_EXIST;
42224349
DG
310 break;
311 default:
312 PERROR("enable kernel event");
313 break;
314 }
19e70852
DG
315 goto error;
316 }
317
318 event->enabled = 1;
319 DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
320
321 return 0;
322
323error:
d36b8583 324 return ret;
19e70852
DG
325}
326
e953ef25 327/*
050349bb 328 * Disable a kernel event.
e953ef25 329 */
19e70852 330int kernel_disable_event(struct ltt_kernel_event *event)
e953ef25
DG
331{
332 int ret;
19e70852 333
0525e9ae
DG
334 assert(event);
335
19e70852 336 ret = kernctl_disable(event->fd);
42224349
DG
337 if (ret < 0) {
338 switch (errno) {
339 case EEXIST:
f73fabfd 340 ret = LTTNG_ERR_KERN_EVENT_EXIST;
42224349
DG
341 break;
342 default:
343 PERROR("disable kernel event");
344 break;
345 }
19e70852 346 goto error;
e953ef25 347 }
f3ed775e 348
19e70852
DG
349 event->enabled = 0;
350 DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
351
f34daff7
DG
352 return 0;
353
354error:
d36b8583 355 return ret;
f34daff7 356}
aaf26714 357
6e911cad
MD
358int kernel_enable_syscall(const char *syscall_name,
359 struct ltt_kernel_channel *channel)
360{
361 return kernctl_enable_syscall(channel->fd, syscall_name);
362}
363
364int kernel_disable_syscall(const char *syscall_name,
365 struct ltt_kernel_channel *channel)
366{
367 return kernctl_disable_syscall(channel->fd, syscall_name);
368}
369
ccf10263
MD
370int kernel_track_pid(struct ltt_kernel_session *session, int pid)
371{
372 DBG("Kernel track PID %d for session id %" PRIu64 ".",
373 pid, session->id);
374 return kernctl_track_pid(session->fd, pid);
375}
376
377int kernel_untrack_pid(struct ltt_kernel_session *session, int pid)
378{
379 DBG("Kernel untrack PID %d for session id %" PRIu64 ".",
380 pid, session->id);
381 return kernctl_untrack_pid(session->fd, pid);
382}
383
aaf26714 384/*
050349bb
DG
385 * Create kernel metadata, open from the kernel tracer and add it to the
386 * kernel session.
aaf26714 387 */
a4b92340 388int kernel_open_metadata(struct ltt_kernel_session *session)
aaf26714
DG
389{
390 int ret;
74024a21 391 struct ltt_kernel_metadata *lkm = NULL;
aaf26714 392
0525e9ae
DG
393 assert(session);
394
54012638 395 /* Allocate kernel metadata */
a4b92340 396 lkm = trace_kernel_create_metadata();
54012638 397 if (lkm == NULL) {
aaf26714
DG
398 goto error;
399 }
400
54012638 401 /* Kernel tracer metadata creation */
f3ed775e 402 ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
aaf26714 403 if (ret < 0) {
74024a21 404 goto error_open;
aaf26714
DG
405 }
406
8c0faa1d 407 lkm->fd = ret;
7b395890
DG
408 /* Prevent fd duplication after execlp() */
409 ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
410 if (ret < 0) {
df0f840b 411 PERROR("fcntl session fd");
7b395890
DG
412 }
413
aaf26714 414 session->metadata = lkm;
8c0faa1d 415
00e2e675 416 DBG("Kernel metadata opened (fd: %d)", lkm->fd);
8c0faa1d
DG
417
418 return 0;
419
74024a21
DG
420error_open:
421 trace_kernel_destroy_metadata(lkm);
8c0faa1d 422error:
54012638 423 return -1;
8c0faa1d
DG
424}
425
426/*
050349bb 427 * Start tracing session.
8c0faa1d
DG
428 */
429int kernel_start_session(struct ltt_kernel_session *session)
430{
431 int ret;
432
0525e9ae
DG
433 assert(session);
434
8c0faa1d
DG
435 ret = kernctl_start_session(session->fd);
436 if (ret < 0) {
df0f840b 437 PERROR("ioctl start session");
8c0faa1d
DG
438 goto error;
439 }
440
441 DBG("Kernel session started");
442
443 return 0;
444
445error:
446 return ret;
447}
448
f3ed775e 449/*
050349bb 450 * Make a kernel wait to make sure in-flight probe have completed.
f3ed775e
DG
451 */
452void kernel_wait_quiescent(int fd)
453{
454 int ret;
455
456 DBG("Kernel quiescent wait on %d", fd);
457
458 ret = kernctl_wait_quiescent(fd);
459 if (ret < 0) {
df0f840b 460 PERROR("wait quiescent ioctl");
f3ed775e
DG
461 ERR("Kernel quiescent wait failed");
462 }
463}
464
d0254c7c 465/*
050349bb 466 * Kernel calibrate
d0254c7c
MD
467 */
468int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate)
469{
470 int ret;
471
0525e9ae
DG
472 assert(calibrate);
473
d0254c7c
MD
474 ret = kernctl_calibrate(fd, calibrate);
475 if (ret < 0) {
df0f840b 476 PERROR("calibrate ioctl");
d0254c7c
MD
477 return -1;
478 }
479
480 return 0;
481}
482
483
f3ed775e 484/*
f3ed775e
DG
485 * Force flush buffer of metadata.
486 */
487int kernel_metadata_flush_buffer(int fd)
488{
489 int ret;
490
169d2cb7
DG
491 DBG("Kernel flushing metadata buffer on fd %d", fd);
492
f3ed775e
DG
493 ret = kernctl_buffer_flush(fd);
494 if (ret < 0) {
00e2e675 495 ERR("Fail to flush metadata buffers %d (ret: %d)", fd, ret);
f3ed775e
DG
496 }
497
498 return 0;
499}
500
501/*
050349bb 502 * Force flush buffer for channel.
f3ed775e
DG
503 */
504int kernel_flush_buffer(struct ltt_kernel_channel *channel)
505{
506 int ret;
507 struct ltt_kernel_stream *stream;
508
0525e9ae
DG
509 assert(channel);
510
f3ed775e
DG
511 DBG("Flush buffer for channel %s", channel->channel->name);
512
513 cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
514 DBG("Flushing channel stream %d", stream->fd);
515 ret = kernctl_buffer_flush(stream->fd);
516 if (ret < 0) {
df0f840b 517 PERROR("ioctl");
f3ed775e
DG
518 ERR("Fail to flush buffer for stream %d (ret: %d)",
519 stream->fd, ret);
520 }
521 }
522
523 return 0;
524}
525
8c0faa1d 526/*
050349bb 527 * Stop tracing session.
8c0faa1d
DG
528 */
529int kernel_stop_session(struct ltt_kernel_session *session)
530{
531 int ret;
532
0525e9ae
DG
533 assert(session);
534
8c0faa1d
DG
535 ret = kernctl_stop_session(session->fd);
536 if (ret < 0) {
537 goto error;
538 }
539
540 DBG("Kernel session stopped");
541
542 return 0;
543
544error:
545 return ret;
546}
547
548/*
050349bb
DG
549 * Open stream of channel, register it to the kernel tracer and add it
550 * to the stream list of the channel.
8c0faa1d 551 *
050349bb 552 * Return the number of created stream. Else, a negative value.
8c0faa1d 553 */
f3ed775e 554int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
8c0faa1d 555{
00e2e675 556 int ret, count = 0;
8c0faa1d
DG
557 struct ltt_kernel_stream *lks;
558
0525e9ae
DG
559 assert(channel);
560
5a47c6a2 561 while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
00e2e675 562 lks = trace_kernel_create_stream(channel->channel->name, count);
8c0faa1d 563 if (lks == NULL) {
799e2c4f
MD
564 ret = close(ret);
565 if (ret) {
566 PERROR("close");
567 }
8c0faa1d
DG
568 goto error;
569 }
570
571 lks->fd = ret;
7b395890
DG
572 /* Prevent fd duplication after execlp() */
573 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
574 if (ret < 0) {
df0f840b 575 PERROR("fcntl session fd");
7b395890
DG
576 }
577
1624d5b7
JD
578 lks->tracefile_size = channel->channel->attr.tracefile_size;
579 lks->tracefile_count = channel->channel->attr.tracefile_count;
580
54012638 581 /* Add stream to channe stream list */
8c0faa1d
DG
582 cds_list_add(&lks->list, &channel->stream_list.head);
583 channel->stream_count++;
8c0faa1d 584
00e2e675
DG
585 /* Increment counter which represent CPU number. */
586 count++;
587
588 DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd,
589 lks->state);
54012638 590 }
8c0faa1d
DG
591
592 return channel->stream_count;
593
594error:
54012638 595 return -1;
8c0faa1d
DG
596}
597
598/*
050349bb 599 * Open the metadata stream and set it to the kernel session.
8c0faa1d 600 */
f3ed775e 601int kernel_open_metadata_stream(struct ltt_kernel_session *session)
8c0faa1d
DG
602{
603 int ret;
604
0525e9ae
DG
605 assert(session);
606
8c0faa1d
DG
607 ret = kernctl_create_stream(session->metadata->fd);
608 if (ret < 0) {
df0f840b 609 PERROR("kernel create metadata stream");
8c0faa1d
DG
610 goto error;
611 }
612
613 DBG("Kernel metadata stream created (fd: %d)", ret);
614 session->metadata_stream_fd = ret;
7b395890
DG
615 /* Prevent fd duplication after execlp() */
616 ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
617 if (ret < 0) {
df0f840b 618 PERROR("fcntl session fd");
7b395890 619 }
aaf26714
DG
620
621 return 0;
622
623error:
54012638 624 return -1;
aaf26714 625}
2ef84c95
DG
626
627/*
9f19cc17 628 * Get the event list from the kernel tracer and return the number of elements.
2ef84c95 629 */
9f19cc17 630ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
2ef84c95 631{
53efb85a 632 int fd, ret;
9f19cc17
DG
633 char *event;
634 size_t nbmem, count = 0;
2ef84c95 635 FILE *fp;
9f19cc17 636 struct lttng_event *elist;
2ef84c95 637
0525e9ae
DG
638 assert(events);
639
2ef84c95
DG
640 fd = kernctl_tracepoint_list(tracer_fd);
641 if (fd < 0) {
df0f840b 642 PERROR("kernel tracepoint list");
2ef84c95
DG
643 goto error;
644 }
645
646 fp = fdopen(fd, "r");
647 if (fp == NULL) {
df0f840b 648 PERROR("kernel tracepoint list fdopen");
61b73b12 649 goto error_fp;
2ef84c95
DG
650 }
651
652 /*
653 * Init memory size counter
654 * See kernel-ctl.h for explanation of this value
655 */
6725fe19 656 nbmem = KERNEL_EVENT_INIT_LIST_SIZE;
ba7f0ae5 657 elist = zmalloc(sizeof(struct lttng_event) * nbmem);
3b870559
MD
658 if (elist == NULL) {
659 PERROR("alloc list events");
660 count = -ENOMEM;
661 goto end;
662 }
2ef84c95 663
53efb85a 664 while (fscanf(fp, "event { name = %m[^;]; };\n", &event) == 1) {
6725fe19 665 if (count >= nbmem) {
3b870559 666 struct lttng_event *new_elist;
53efb85a 667 size_t new_nbmem;
3b870559 668
53efb85a
MD
669 new_nbmem = nbmem << 1;
670 DBG("Reallocating event list from %zu to %zu bytes",
671 nbmem, new_nbmem);
672 new_elist = realloc(elist, new_nbmem * sizeof(struct lttng_event));
3b870559 673 if (new_elist == NULL) {
df0f840b 674 PERROR("realloc list events");
3b870559
MD
675 free(event);
676 free(elist);
61b73b12
MD
677 count = -ENOMEM;
678 goto end;
2ef84c95 679 }
53efb85a
MD
680 /* Zero the new memory */
681 memset(new_elist + nbmem, 0,
682 (new_nbmem - nbmem) * sizeof(struct lttng_event));
683 nbmem = new_nbmem;
3b870559 684 elist = new_elist;
2ef84c95 685 }
99497cd0
MD
686 strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
687 elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
67b9d018 688 elist[count].enabled = -1;
9f19cc17 689 count++;
3b870559 690 free(event);
2ef84c95
DG
691 }
692
9f19cc17 693 *events = elist;
ced2f820 694 DBG("Kernel list events done (%zu events)", count);
61b73b12 695end:
799e2c4f
MD
696 ret = fclose(fp); /* closes both fp and fd */
697 if (ret) {
698 PERROR("fclose");
699 }
9f19cc17 700 return count;
2ef84c95 701
61b73b12 702error_fp:
799e2c4f
MD
703 ret = close(fd);
704 if (ret) {
705 PERROR("close");
706 }
2ef84c95
DG
707error:
708 return -1;
709}
096102bd
DG
710
711/*
712 * Get kernel version and validate it.
713 */
714int kernel_validate_version(int tracer_fd)
715{
716 int ret;
717 struct lttng_kernel_tracer_version version;
c052142c 718 struct lttng_kernel_tracer_abi_version abi_version;
096102bd
DG
719
720 ret = kernctl_tracer_version(tracer_fd, &version);
721 if (ret < 0) {
722 ERR("Failed at getting the lttng-modules version");
723 goto error;
724 }
725
726 /* Validate version */
c052142c
MD
727 if (version.major != VERSION_MAJOR) {
728 ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
729 version.major, VERSION_MAJOR);
096102bd 730 goto error_version;
096102bd 731 }
c052142c
MD
732 ret = kernctl_tracer_abi_version(tracer_fd, &abi_version);
733 if (ret < 0) {
734 ERR("Failed at getting lttng-modules ABI version");
735 goto error;
736 }
737 if (abi_version.major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
738 ERR("Kernel tracer ABI version (%d.%d) is not compatible with expected ABI major version (%d.*)",
739 abi_version.major, abi_version.minor,
740 LTTNG_MODULES_ABI_MAJOR_VERSION);
741 goto error;
742 }
743 DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
744 version.major, version.minor,
745 abi_version.major, abi_version.minor);
096102bd
DG
746 return 0;
747
748error_version:
096102bd
DG
749 ret = -1;
750
751error:
752 return ret;
753}
335a95b7
MD
754
755/*
756 * Kernel work-arounds called at the start of sessiond main().
757 */
758int init_kernel_workarounds(void)
759{
8936c33a 760 int ret;
335a95b7
MD
761 FILE *fp;
762
763 /*
764 * boot_id needs to be read once before being used concurrently
765 * to deal with a Linux kernel race. A fix is proposed for
766 * upstream, but the work-around is needed for older kernels.
767 */
768 fp = fopen("/proc/sys/kernel/random/boot_id", "r");
769 if (!fp) {
770 goto end_boot_id;
771 }
772 while (!feof(fp)) {
773 char buf[37] = "";
774
8936c33a
DG
775 ret = fread(buf, 1, sizeof(buf), fp);
776 if (ret < 0) {
777 /* Ignore error, we don't really care */
778 }
335a95b7 779 }
799e2c4f
MD
780 ret = fclose(fp);
781 if (ret) {
782 PERROR("fclose");
783 }
335a95b7 784end_boot_id:
335a95b7
MD
785 return 0;
786}
2f77fc4b
DG
787
788/*
789 * Complete teardown of a kernel session.
790 */
791void kernel_destroy_session(struct ltt_kernel_session *ksess)
792{
793 if (ksess == NULL) {
794 DBG3("No kernel session when tearing down session");
795 return;
796 }
797
798 DBG("Tearing down kernel session");
799
07b86b52 800 /*
15dc512a
DG
801 * Destroy channels on the consumer if at least one FD has been sent and we
802 * are in no output mode because the streams are in *no* monitor mode so we
803 * have to send a command to clean them up or else they leaked.
07b86b52 804 */
15dc512a 805 if (!ksess->output_traces && ksess->consumer_fds_sent) {
07b86b52
JD
806 int ret;
807 struct consumer_socket *socket;
808 struct lttng_ht_iter iter;
809
810 /* For each consumer socket. */
d069d577 811 rcu_read_lock();
07b86b52
JD
812 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
813 socket, node.node) {
814 struct ltt_kernel_channel *chan;
815
816 /* For each channel, ask the consumer to destroy it. */
817 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
818 ret = kernel_consumer_destroy_channel(socket, chan);
819 if (ret < 0) {
820 /* Consumer is probably dead. Use next socket. */
821 continue;
822 }
823 }
824 }
d069d577 825 rcu_read_unlock();
07b86b52
JD
826 }
827
2f77fc4b
DG
828 /* Close any relayd session */
829 consumer_output_send_destroy_relayd(ksess->consumer);
830
831 trace_kernel_destroy_session(ksess);
832}
fb5f35b6
DG
833
834/*
835 * Destroy a kernel channel object. It does not do anything on the tracer side.
836 */
837void kernel_destroy_channel(struct ltt_kernel_channel *kchan)
838{
839 struct ltt_kernel_session *ksess = NULL;
840
841 assert(kchan);
842 assert(kchan->channel);
843
844 DBG3("Kernel destroy channel %s", kchan->channel->name);
845
846 /* Update channel count of associated session. */
847 if (kchan->session) {
848 /* Keep pointer reference so we can update it after the destroy. */
849 ksess = kchan->session;
850 }
851
852 trace_kernel_destroy_channel(kchan);
853
854 /*
855 * At this point the kernel channel is not visible anymore. This is safe
856 * since in order to work on a visible kernel session, the tracing session
857 * lock (ltt_session.lock) MUST be acquired.
858 */
859 if (ksess) {
860 ksess->channel_count--;
861 }
862}
6dc3064a
DG
863
864/*
865 * Take a snapshot for a given kernel session.
866 *
2a06df8d 867 * Return 0 on success or else return a LTTNG_ERR code.
6dc3064a
DG
868 */
869int kernel_snapshot_record(struct ltt_kernel_session *ksess,
d07ceecd
MD
870 struct snapshot_output *output, int wait,
871 uint64_t nb_packets_per_stream)
6dc3064a 872{
2a06df8d 873 int err, ret, saved_metadata_fd;
6dc3064a
DG
874 struct consumer_socket *socket;
875 struct lttng_ht_iter iter;
876 struct ltt_kernel_metadata *saved_metadata;
877
878 assert(ksess);
879 assert(ksess->consumer);
880 assert(output);
881
882 DBG("Kernel snapshot record started");
883
884 /* Save current metadata since the following calls will change it. */
885 saved_metadata = ksess->metadata;
886 saved_metadata_fd = ksess->metadata_stream_fd;
887
888 rcu_read_lock();
889
890 ret = kernel_open_metadata(ksess);
891 if (ret < 0) {
892 ret = LTTNG_ERR_KERN_META_FAIL;
893 goto error;
894 }
895
896 ret = kernel_open_metadata_stream(ksess);
897 if (ret < 0) {
898 ret = LTTNG_ERR_KERN_META_FAIL;
899 goto error_open_stream;
900 }
901
902 /* Send metadata to consumer and snapshot everything. */
903 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
904 socket, node.node) {
905 struct consumer_output *saved_output;
906 struct ltt_kernel_channel *chan;
6dc3064a
DG
907
908 /*
909 * Temporarly switch consumer output for our snapshot output. As long
910 * as the session lock is taken, this is safe.
911 */
912 saved_output = ksess->consumer;
913 ksess->consumer = output->consumer;
914
915 pthread_mutex_lock(socket->lock);
916 /* This stream must not be monitored by the consumer. */
07b86b52 917 ret = kernel_consumer_add_metadata(socket, ksess, 0);
6dc3064a 918 pthread_mutex_unlock(socket->lock);
07b86b52 919 /* Put back the saved consumer output into the session. */
6dc3064a
DG
920 ksess->consumer = saved_output;
921 if (ret < 0) {
922 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
923 goto error_consumer;
924 }
925
926 /* For each channel, ask the consumer to snapshot it. */
927 cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
07b86b52 928 pthread_mutex_lock(socket->lock);
6dc3064a 929 ret = consumer_snapshot_channel(socket, chan->fd, output, 0,
5c786ded
JD
930 ksess->uid, ksess->gid,
931 DEFAULT_KERNEL_TRACE_DIR, wait,
d07ceecd 932 nb_packets_per_stream);
07b86b52 933 pthread_mutex_unlock(socket->lock);
6dc3064a
DG
934 if (ret < 0) {
935 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
2a06df8d
DG
936 (void) kernel_consumer_destroy_metadata(socket,
937 ksess->metadata);
6dc3064a
DG
938 goto error_consumer;
939 }
940 }
941
942 /* Snapshot metadata, */
07b86b52 943 pthread_mutex_lock(socket->lock);
6dc3064a 944 ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output,
5c786ded 945 1, ksess->uid, ksess->gid,
d07ceecd 946 DEFAULT_KERNEL_TRACE_DIR, wait, 0);
07b86b52 947 pthread_mutex_unlock(socket->lock);
6dc3064a
DG
948 if (ret < 0) {
949 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
950 goto error_consumer;
951 }
07b86b52
JD
952
953 /*
954 * The metadata snapshot is done, ask the consumer to destroy it since
955 * it's not monitored on the consumer side.
956 */
957 (void) kernel_consumer_destroy_metadata(socket, ksess->metadata);
6dc3064a
DG
958 }
959
fac41e72
DG
960 ret = LTTNG_OK;
961
6dc3064a
DG
962error_consumer:
963 /* Close newly opened metadata stream. It's now on the consumer side. */
2a06df8d
DG
964 err = close(ksess->metadata_stream_fd);
965 if (err < 0) {
6dc3064a
DG
966 PERROR("close snapshot kernel");
967 }
968
969error_open_stream:
970 trace_kernel_destroy_metadata(ksess->metadata);
971error:
972 /* Restore metadata state.*/
973 ksess->metadata = saved_metadata;
974 ksess->metadata_stream_fd = saved_metadata_fd;
975
976 rcu_read_unlock();
977 return ret;
978}
834978fd
DG
979
980/*
981 * Get the syscall mask array from the kernel tracer.
982 *
983 * Return 0 on success else a negative value. In both case, syscall_mask should
984 * be freed.
985 */
986int kernel_syscall_mask(int chan_fd, char **syscall_mask, uint32_t *nr_bits)
987{
988 assert(syscall_mask);
989 assert(nr_bits);
990
991 return kernctl_syscall_mask(chan_fd, syscall_mask, nr_bits);
992}
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