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Fix: add missing versions and init call for page_alloc wrapper
[lttng-modules.git] / lttng-events.c
1 /*
2 * lttng-events.c
3 *
4 * Holds LTTng per-session event registry.
5 *
6 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /*
24 * This page_alloc.h wrapper needs to be included before gfpflags.h because it
25 * overrides a function with a define.
26 */
27 #include "wrapper/page_alloc.h"
28
29 #include <linux/module.h>
30 #include <linux/mutex.h>
31 #include <linux/sched.h>
32 #include <linux/slab.h>
33 #include <linux/jiffies.h>
34 #include <linux/utsname.h>
35 #include <linux/err.h>
36 #include <linux/seq_file.h>
37 #include <linux/file.h>
38 #include <linux/anon_inodes.h>
39 #include "wrapper/file.h"
40 #include <linux/jhash.h>
41 #include <linux/uaccess.h>
42 #include <linux/vmalloc.h>
43
44 #include "wrapper/uuid.h"
45 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
46 #include "wrapper/random.h"
47 #include "wrapper/tracepoint.h"
48 #include "wrapper/list.h"
49 #include "lttng-kernel-version.h"
50 #include "lttng-events.h"
51 #include "lttng-tracer.h"
52 #include "lttng-abi-old.h"
53 #include "wrapper/vzalloc.h"
54
55 #define METADATA_CACHE_DEFAULT_SIZE 4096
56
57 static LIST_HEAD(sessions);
58 static LIST_HEAD(lttng_transport_list);
59 /*
60 * Protect the sessions and metadata caches.
61 */
62 static DEFINE_MUTEX(sessions_mutex);
63 static struct kmem_cache *event_cache;
64
65 static void lttng_session_lazy_sync_enablers(struct lttng_session *session);
66 static void lttng_session_sync_enablers(struct lttng_session *session);
67 static void lttng_enabler_destroy(struct lttng_enabler *enabler);
68
69 static void _lttng_event_destroy(struct lttng_event *event);
70 static void _lttng_channel_destroy(struct lttng_channel *chan);
71 static int _lttng_event_unregister(struct lttng_event *event);
72 static
73 int _lttng_event_metadata_statedump(struct lttng_session *session,
74 struct lttng_channel *chan,
75 struct lttng_event *event);
76 static
77 int _lttng_session_metadata_statedump(struct lttng_session *session);
78 static
79 void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream);
80
81 void synchronize_trace(void)
82 {
83 synchronize_sched();
84 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0))
85 #ifdef CONFIG_PREEMPT_RT_FULL
86 synchronize_rcu();
87 #endif
88 #else /* (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) */
89 #ifdef CONFIG_PREEMPT_RT
90 synchronize_rcu();
91 #endif
92 #endif /* (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) */
93 }
94
95 void lttng_lock_sessions(void)
96 {
97 mutex_lock(&sessions_mutex);
98 }
99
100 void lttng_unlock_sessions(void)
101 {
102 mutex_unlock(&sessions_mutex);
103 }
104
105 /*
106 * Called with sessions lock held.
107 */
108 int lttng_session_active(void)
109 {
110 struct lttng_session *iter;
111
112 list_for_each_entry(iter, &sessions, list) {
113 if (iter->active)
114 return 1;
115 }
116 return 0;
117 }
118
119 struct lttng_session *lttng_session_create(void)
120 {
121 struct lttng_session *session;
122 struct lttng_metadata_cache *metadata_cache;
123 int i;
124
125 mutex_lock(&sessions_mutex);
126 session = kzalloc(sizeof(struct lttng_session), GFP_KERNEL);
127 if (!session)
128 goto err;
129 INIT_LIST_HEAD(&session->chan);
130 INIT_LIST_HEAD(&session->events);
131 uuid_le_gen(&session->uuid);
132
133 metadata_cache = kzalloc(sizeof(struct lttng_metadata_cache),
134 GFP_KERNEL);
135 if (!metadata_cache)
136 goto err_free_session;
137 metadata_cache->data = lttng_vzalloc(METADATA_CACHE_DEFAULT_SIZE);
138 if (!metadata_cache->data)
139 goto err_free_cache;
140 metadata_cache->cache_alloc = METADATA_CACHE_DEFAULT_SIZE;
141 kref_init(&metadata_cache->refcount);
142 mutex_init(&metadata_cache->lock);
143 session->metadata_cache = metadata_cache;
144 INIT_LIST_HEAD(&metadata_cache->metadata_stream);
145 memcpy(&metadata_cache->uuid, &session->uuid,
146 sizeof(metadata_cache->uuid));
147 INIT_LIST_HEAD(&session->enablers_head);
148 for (i = 0; i < LTTNG_EVENT_HT_SIZE; i++)
149 INIT_HLIST_HEAD(&session->events_ht.table[i]);
150 list_add(&session->list, &sessions);
151 mutex_unlock(&sessions_mutex);
152 return session;
153
154 err_free_cache:
155 kfree(metadata_cache);
156 err_free_session:
157 kfree(session);
158 err:
159 mutex_unlock(&sessions_mutex);
160 return NULL;
161 }
162
163 void metadata_cache_destroy(struct kref *kref)
164 {
165 struct lttng_metadata_cache *cache =
166 container_of(kref, struct lttng_metadata_cache, refcount);
167 vfree(cache->data);
168 kfree(cache);
169 }
170
171 void lttng_session_destroy(struct lttng_session *session)
172 {
173 struct lttng_channel *chan, *tmpchan;
174 struct lttng_event *event, *tmpevent;
175 struct lttng_metadata_stream *metadata_stream;
176 struct lttng_enabler *enabler, *tmpenabler;
177 int ret;
178
179 mutex_lock(&sessions_mutex);
180 ACCESS_ONCE(session->active) = 0;
181 list_for_each_entry(chan, &session->chan, list) {
182 ret = lttng_syscalls_unregister(chan);
183 WARN_ON(ret);
184 }
185 list_for_each_entry(event, &session->events, list) {
186 ret = _lttng_event_unregister(event);
187 WARN_ON(ret);
188 }
189 synchronize_trace(); /* Wait for in-flight events to complete */
190 list_for_each_entry_safe(enabler, tmpenabler,
191 &session->enablers_head, node)
192 lttng_enabler_destroy(enabler);
193 list_for_each_entry_safe(event, tmpevent, &session->events, list)
194 _lttng_event_destroy(event);
195 list_for_each_entry_safe(chan, tmpchan, &session->chan, list) {
196 BUG_ON(chan->channel_type == METADATA_CHANNEL);
197 _lttng_channel_destroy(chan);
198 }
199 list_for_each_entry(metadata_stream, &session->metadata_cache->metadata_stream, list)
200 _lttng_metadata_channel_hangup(metadata_stream);
201 if (session->pid_tracker)
202 lttng_pid_tracker_destroy(session->pid_tracker);
203 kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
204 list_del(&session->list);
205 mutex_unlock(&sessions_mutex);
206 kfree(session);
207 }
208
209 int lttng_session_enable(struct lttng_session *session)
210 {
211 int ret = 0;
212 struct lttng_channel *chan;
213
214 mutex_lock(&sessions_mutex);
215 if (session->active) {
216 ret = -EBUSY;
217 goto end;
218 }
219
220 /* Set transient enabler state to "enabled" */
221 session->tstate = 1;
222
223 /*
224 * Snapshot the number of events per channel to know the type of header
225 * we need to use.
226 */
227 list_for_each_entry(chan, &session->chan, list) {
228 if (chan->header_type)
229 continue; /* don't change it if session stop/restart */
230 if (chan->free_event_id < 31)
231 chan->header_type = 1; /* compact */
232 else
233 chan->header_type = 2; /* large */
234 }
235
236 /* We need to sync enablers with session before activation. */
237 lttng_session_sync_enablers(session);
238
239 ACCESS_ONCE(session->active) = 1;
240 ACCESS_ONCE(session->been_active) = 1;
241 ret = _lttng_session_metadata_statedump(session);
242 if (ret) {
243 ACCESS_ONCE(session->active) = 0;
244 goto end;
245 }
246 ret = lttng_statedump_start(session);
247 if (ret)
248 ACCESS_ONCE(session->active) = 0;
249 end:
250 mutex_unlock(&sessions_mutex);
251 return ret;
252 }
253
254 int lttng_session_disable(struct lttng_session *session)
255 {
256 int ret = 0;
257
258 mutex_lock(&sessions_mutex);
259 if (!session->active) {
260 ret = -EBUSY;
261 goto end;
262 }
263 ACCESS_ONCE(session->active) = 0;
264
265 /* Set transient enabler state to "disabled" */
266 session->tstate = 0;
267 lttng_session_sync_enablers(session);
268 end:
269 mutex_unlock(&sessions_mutex);
270 return ret;
271 }
272
273 int lttng_channel_enable(struct lttng_channel *channel)
274 {
275 int ret = 0;
276
277 mutex_lock(&sessions_mutex);
278 if (channel->channel_type == METADATA_CHANNEL) {
279 ret = -EPERM;
280 goto end;
281 }
282 if (channel->enabled) {
283 ret = -EEXIST;
284 goto end;
285 }
286 /* Set transient enabler state to "enabled" */
287 channel->tstate = 1;
288 lttng_session_sync_enablers(channel->session);
289 /* Set atomically the state to "enabled" */
290 ACCESS_ONCE(channel->enabled) = 1;
291 end:
292 mutex_unlock(&sessions_mutex);
293 return ret;
294 }
295
296 int lttng_channel_disable(struct lttng_channel *channel)
297 {
298 int ret = 0;
299
300 mutex_lock(&sessions_mutex);
301 if (channel->channel_type == METADATA_CHANNEL) {
302 ret = -EPERM;
303 goto end;
304 }
305 if (!channel->enabled) {
306 ret = -EEXIST;
307 goto end;
308 }
309 /* Set atomically the state to "disabled" */
310 ACCESS_ONCE(channel->enabled) = 0;
311 /* Set transient enabler state to "enabled" */
312 channel->tstate = 0;
313 lttng_session_sync_enablers(channel->session);
314 end:
315 mutex_unlock(&sessions_mutex);
316 return ret;
317 }
318
319 int lttng_event_enable(struct lttng_event *event)
320 {
321 int ret = 0;
322
323 mutex_lock(&sessions_mutex);
324 if (event->chan->channel_type == METADATA_CHANNEL) {
325 ret = -EPERM;
326 goto end;
327 }
328 if (event->enabled) {
329 ret = -EEXIST;
330 goto end;
331 }
332 switch (event->instrumentation) {
333 case LTTNG_KERNEL_TRACEPOINT:
334 case LTTNG_KERNEL_SYSCALL:
335 ret = -EINVAL;
336 break;
337 case LTTNG_KERNEL_KPROBE:
338 case LTTNG_KERNEL_FUNCTION:
339 case LTTNG_KERNEL_NOOP:
340 ACCESS_ONCE(event->enabled) = 1;
341 break;
342 case LTTNG_KERNEL_KRETPROBE:
343 ret = lttng_kretprobes_event_enable_state(event, 1);
344 break;
345 default:
346 WARN_ON_ONCE(1);
347 ret = -EINVAL;
348 }
349 end:
350 mutex_unlock(&sessions_mutex);
351 return ret;
352 }
353
354 int lttng_event_disable(struct lttng_event *event)
355 {
356 int ret = 0;
357
358 mutex_lock(&sessions_mutex);
359 if (event->chan->channel_type == METADATA_CHANNEL) {
360 ret = -EPERM;
361 goto end;
362 }
363 if (!event->enabled) {
364 ret = -EEXIST;
365 goto end;
366 }
367 switch (event->instrumentation) {
368 case LTTNG_KERNEL_TRACEPOINT:
369 case LTTNG_KERNEL_SYSCALL:
370 ret = -EINVAL;
371 break;
372 case LTTNG_KERNEL_KPROBE:
373 case LTTNG_KERNEL_FUNCTION:
374 case LTTNG_KERNEL_NOOP:
375 ACCESS_ONCE(event->enabled) = 0;
376 break;
377 case LTTNG_KERNEL_KRETPROBE:
378 ret = lttng_kretprobes_event_enable_state(event, 0);
379 break;
380 default:
381 WARN_ON_ONCE(1);
382 ret = -EINVAL;
383 }
384 end:
385 mutex_unlock(&sessions_mutex);
386 return ret;
387 }
388
389 static struct lttng_transport *lttng_transport_find(const char *name)
390 {
391 struct lttng_transport *transport;
392
393 list_for_each_entry(transport, &lttng_transport_list, node) {
394 if (!strcmp(transport->name, name))
395 return transport;
396 }
397 return NULL;
398 }
399
400 struct lttng_channel *lttng_channel_create(struct lttng_session *session,
401 const char *transport_name,
402 void *buf_addr,
403 size_t subbuf_size, size_t num_subbuf,
404 unsigned int switch_timer_interval,
405 unsigned int read_timer_interval,
406 enum channel_type channel_type)
407 {
408 struct lttng_channel *chan;
409 struct lttng_transport *transport = NULL;
410
411 mutex_lock(&sessions_mutex);
412 if (session->been_active && channel_type != METADATA_CHANNEL)
413 goto active; /* Refuse to add channel to active session */
414 transport = lttng_transport_find(transport_name);
415 if (!transport) {
416 printk(KERN_WARNING "LTTng transport %s not found\n",
417 transport_name);
418 goto notransport;
419 }
420 if (!try_module_get(transport->owner)) {
421 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
422 goto notransport;
423 }
424 chan = kzalloc(sizeof(struct lttng_channel), GFP_KERNEL);
425 if (!chan)
426 goto nomem;
427 chan->session = session;
428 chan->id = session->free_chan_id++;
429 chan->ops = &transport->ops;
430 /*
431 * Note: the channel creation op already writes into the packet
432 * headers. Therefore the "chan" information used as input
433 * should be already accessible.
434 */
435 chan->chan = transport->ops.channel_create(transport_name,
436 chan, buf_addr, subbuf_size, num_subbuf,
437 switch_timer_interval, read_timer_interval);
438 if (!chan->chan)
439 goto create_error;
440 chan->tstate = 1;
441 chan->enabled = 1;
442 chan->transport = transport;
443 chan->channel_type = channel_type;
444 list_add(&chan->list, &session->chan);
445 mutex_unlock(&sessions_mutex);
446 return chan;
447
448 create_error:
449 kfree(chan);
450 nomem:
451 if (transport)
452 module_put(transport->owner);
453 notransport:
454 active:
455 mutex_unlock(&sessions_mutex);
456 return NULL;
457 }
458
459 /*
460 * Only used internally at session destruction for per-cpu channels, and
461 * when metadata channel is released.
462 * Needs to be called with sessions mutex held.
463 */
464 static
465 void _lttng_channel_destroy(struct lttng_channel *chan)
466 {
467 chan->ops->channel_destroy(chan->chan);
468 module_put(chan->transport->owner);
469 list_del(&chan->list);
470 lttng_destroy_context(chan->ctx);
471 kfree(chan);
472 }
473
474 void lttng_metadata_channel_destroy(struct lttng_channel *chan)
475 {
476 BUG_ON(chan->channel_type != METADATA_CHANNEL);
477
478 /* Protect the metadata cache with the sessions_mutex. */
479 mutex_lock(&sessions_mutex);
480 _lttng_channel_destroy(chan);
481 mutex_unlock(&sessions_mutex);
482 }
483 EXPORT_SYMBOL_GPL(lttng_metadata_channel_destroy);
484
485 static
486 void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream)
487 {
488 stream->finalized = 1;
489 wake_up_interruptible(&stream->read_wait);
490 }
491
492 /*
493 * Supports event creation while tracing session is active.
494 * Needs to be called with sessions mutex held.
495 */
496 struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
497 struct lttng_kernel_event *event_param,
498 void *filter,
499 const struct lttng_event_desc *event_desc,
500 enum lttng_kernel_instrumentation itype)
501 {
502 struct lttng_session *session = chan->session;
503 struct lttng_event *event;
504 const char *event_name;
505 struct hlist_head *head;
506 size_t name_len;
507 uint32_t hash;
508 int ret;
509
510 if (chan->free_event_id == -1U) {
511 ret = -EMFILE;
512 goto full;
513 }
514
515 switch (itype) {
516 case LTTNG_KERNEL_TRACEPOINT:
517 event_name = event_desc->name;
518 break;
519 case LTTNG_KERNEL_KPROBE:
520 case LTTNG_KERNEL_KRETPROBE:
521 case LTTNG_KERNEL_FUNCTION:
522 case LTTNG_KERNEL_NOOP:
523 case LTTNG_KERNEL_SYSCALL:
524 event_name = event_param->name;
525 break;
526 default:
527 WARN_ON_ONCE(1);
528 ret = -EINVAL;
529 goto type_error;
530 }
531 name_len = strlen(event_name);
532 hash = jhash(event_name, name_len, 0);
533 head = &session->events_ht.table[hash & (LTTNG_EVENT_HT_SIZE - 1)];
534 lttng_hlist_for_each_entry(event, head, hlist) {
535 WARN_ON_ONCE(!event->desc);
536 if (!strncmp(event->desc->name, event_name,
537 LTTNG_KERNEL_SYM_NAME_LEN - 1)
538 && chan == event->chan) {
539 ret = -EEXIST;
540 goto exist;
541 }
542 }
543
544 event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
545 if (!event) {
546 ret = -ENOMEM;
547 goto cache_error;
548 }
549 event->chan = chan;
550 event->filter = filter;
551 event->id = chan->free_event_id++;
552 event->instrumentation = itype;
553 event->evtype = LTTNG_TYPE_EVENT;
554 INIT_LIST_HEAD(&event->bytecode_runtime_head);
555 INIT_LIST_HEAD(&event->enablers_ref_head);
556
557 switch (itype) {
558 case LTTNG_KERNEL_TRACEPOINT:
559 /* Event will be enabled by enabler sync. */
560 event->enabled = 0;
561 event->registered = 0;
562 event->desc = lttng_event_get(event_name);
563 if (!event->desc) {
564 ret = -ENOENT;
565 goto register_error;
566 }
567 /* Populate lttng_event structure before event registration. */
568 smp_wmb();
569 break;
570 case LTTNG_KERNEL_KPROBE:
571 /*
572 * Needs to be explicitly enabled after creation, since
573 * we may want to apply filters.
574 */
575 event->enabled = 0;
576 event->registered = 1;
577 /*
578 * Populate lttng_event structure before event
579 * registration.
580 */
581 smp_wmb();
582 ret = lttng_kprobes_register(event_name,
583 event_param->u.kprobe.symbol_name,
584 event_param->u.kprobe.offset,
585 event_param->u.kprobe.addr,
586 event);
587 if (ret) {
588 ret = -EINVAL;
589 goto register_error;
590 }
591 ret = try_module_get(event->desc->owner);
592 WARN_ON_ONCE(!ret);
593 break;
594 case LTTNG_KERNEL_KRETPROBE:
595 {
596 struct lttng_event *event_return;
597
598 /* kretprobe defines 2 events */
599 /*
600 * Needs to be explicitly enabled after creation, since
601 * we may want to apply filters.
602 */
603 event->enabled = 0;
604 event->registered = 1;
605 event_return =
606 kmem_cache_zalloc(event_cache, GFP_KERNEL);
607 if (!event_return) {
608 ret = -ENOMEM;
609 goto register_error;
610 }
611 event_return->chan = chan;
612 event_return->filter = filter;
613 event_return->id = chan->free_event_id++;
614 event_return->enabled = 0;
615 event_return->registered = 1;
616 event_return->instrumentation = itype;
617 /*
618 * Populate lttng_event structure before kretprobe registration.
619 */
620 smp_wmb();
621 ret = lttng_kretprobes_register(event_name,
622 event_param->u.kretprobe.symbol_name,
623 event_param->u.kretprobe.offset,
624 event_param->u.kretprobe.addr,
625 event, event_return);
626 if (ret) {
627 kmem_cache_free(event_cache, event_return);
628 ret = -EINVAL;
629 goto register_error;
630 }
631 /* Take 2 refs on the module: one per event. */
632 ret = try_module_get(event->desc->owner);
633 WARN_ON_ONCE(!ret);
634 ret = try_module_get(event->desc->owner);
635 WARN_ON_ONCE(!ret);
636 ret = _lttng_event_metadata_statedump(chan->session, chan,
637 event_return);
638 WARN_ON_ONCE(ret > 0);
639 if (ret) {
640 kmem_cache_free(event_cache, event_return);
641 module_put(event->desc->owner);
642 module_put(event->desc->owner);
643 goto statedump_error;
644 }
645 list_add(&event_return->list, &chan->session->events);
646 break;
647 }
648 case LTTNG_KERNEL_FUNCTION:
649 /*
650 * Needs to be explicitly enabled after creation, since
651 * we may want to apply filters.
652 */
653 event->enabled = 0;
654 event->registered = 1;
655 /*
656 * Populate lttng_event structure before event
657 * registration.
658 */
659 smp_wmb();
660 ret = lttng_ftrace_register(event_name,
661 event_param->u.ftrace.symbol_name,
662 event);
663 if (ret) {
664 goto register_error;
665 }
666 ret = try_module_get(event->desc->owner);
667 WARN_ON_ONCE(!ret);
668 break;
669 case LTTNG_KERNEL_NOOP:
670 case LTTNG_KERNEL_SYSCALL:
671 /*
672 * Needs to be explicitly enabled after creation, since
673 * we may want to apply filters.
674 */
675 event->enabled = 0;
676 event->registered = 0;
677 event->desc = event_desc;
678 if (!event->desc) {
679 ret = -EINVAL;
680 goto register_error;
681 }
682 break;
683 default:
684 WARN_ON_ONCE(1);
685 ret = -EINVAL;
686 goto register_error;
687 }
688 ret = _lttng_event_metadata_statedump(chan->session, chan, event);
689 WARN_ON_ONCE(ret > 0);
690 if (ret) {
691 goto statedump_error;
692 }
693 hlist_add_head(&event->hlist, head);
694 list_add(&event->list, &chan->session->events);
695 return event;
696
697 statedump_error:
698 /* If a statedump error occurs, events will not be readable. */
699 register_error:
700 kmem_cache_free(event_cache, event);
701 cache_error:
702 exist:
703 type_error:
704 full:
705 return ERR_PTR(ret);
706 }
707
708 struct lttng_event *lttng_event_create(struct lttng_channel *chan,
709 struct lttng_kernel_event *event_param,
710 void *filter,
711 const struct lttng_event_desc *event_desc,
712 enum lttng_kernel_instrumentation itype)
713 {
714 struct lttng_event *event;
715
716 mutex_lock(&sessions_mutex);
717 event = _lttng_event_create(chan, event_param, filter, event_desc,
718 itype);
719 mutex_unlock(&sessions_mutex);
720 return event;
721 }
722
723 /* Only used for tracepoints for now. */
724 static
725 void register_event(struct lttng_event *event)
726 {
727 const struct lttng_event_desc *desc;
728 int ret = -EINVAL;
729
730 if (event->registered)
731 return;
732
733 desc = event->desc;
734 switch (event->instrumentation) {
735 case LTTNG_KERNEL_TRACEPOINT:
736 ret = lttng_wrapper_tracepoint_probe_register(desc->kname,
737 desc->probe_callback,
738 event);
739 break;
740 case LTTNG_KERNEL_SYSCALL:
741 ret = lttng_syscall_filter_enable(event->chan,
742 desc->name);
743 break;
744 case LTTNG_KERNEL_KPROBE:
745 case LTTNG_KERNEL_KRETPROBE:
746 case LTTNG_KERNEL_FUNCTION:
747 case LTTNG_KERNEL_NOOP:
748 ret = 0;
749 break;
750 default:
751 WARN_ON_ONCE(1);
752 }
753 if (!ret)
754 event->registered = 1;
755 }
756
757 /*
758 * Only used internally at session destruction.
759 */
760 int _lttng_event_unregister(struct lttng_event *event)
761 {
762 const struct lttng_event_desc *desc;
763 int ret = -EINVAL;
764
765 if (!event->registered)
766 return 0;
767
768 desc = event->desc;
769 switch (event->instrumentation) {
770 case LTTNG_KERNEL_TRACEPOINT:
771 ret = lttng_wrapper_tracepoint_probe_unregister(event->desc->kname,
772 event->desc->probe_callback,
773 event);
774 break;
775 case LTTNG_KERNEL_KPROBE:
776 lttng_kprobes_unregister(event);
777 ret = 0;
778 break;
779 case LTTNG_KERNEL_KRETPROBE:
780 lttng_kretprobes_unregister(event);
781 ret = 0;
782 break;
783 case LTTNG_KERNEL_FUNCTION:
784 lttng_ftrace_unregister(event);
785 ret = 0;
786 break;
787 case LTTNG_KERNEL_SYSCALL:
788 ret = lttng_syscall_filter_disable(event->chan,
789 desc->name);
790 break;
791 case LTTNG_KERNEL_NOOP:
792 ret = 0;
793 break;
794 default:
795 WARN_ON_ONCE(1);
796 }
797 if (!ret)
798 event->registered = 0;
799 return ret;
800 }
801
802 /*
803 * Only used internally at session destruction.
804 */
805 static
806 void _lttng_event_destroy(struct lttng_event *event)
807 {
808 switch (event->instrumentation) {
809 case LTTNG_KERNEL_TRACEPOINT:
810 lttng_event_put(event->desc);
811 break;
812 case LTTNG_KERNEL_KPROBE:
813 module_put(event->desc->owner);
814 lttng_kprobes_destroy_private(event);
815 break;
816 case LTTNG_KERNEL_KRETPROBE:
817 module_put(event->desc->owner);
818 lttng_kretprobes_destroy_private(event);
819 break;
820 case LTTNG_KERNEL_FUNCTION:
821 module_put(event->desc->owner);
822 lttng_ftrace_destroy_private(event);
823 break;
824 case LTTNG_KERNEL_NOOP:
825 case LTTNG_KERNEL_SYSCALL:
826 break;
827 default:
828 WARN_ON_ONCE(1);
829 }
830 list_del(&event->list);
831 lttng_destroy_context(event->ctx);
832 kmem_cache_free(event_cache, event);
833 }
834
835 int lttng_session_track_pid(struct lttng_session *session, int pid)
836 {
837 int ret;
838
839 if (pid < -1)
840 return -EINVAL;
841 mutex_lock(&sessions_mutex);
842 if (pid == -1) {
843 /* track all pids: destroy tracker. */
844 if (session->pid_tracker) {
845 struct lttng_pid_tracker *lpf;
846
847 lpf = session->pid_tracker;
848 rcu_assign_pointer(session->pid_tracker, NULL);
849 synchronize_trace();
850 lttng_pid_tracker_destroy(lpf);
851 }
852 ret = 0;
853 } else {
854 if (!session->pid_tracker) {
855 struct lttng_pid_tracker *lpf;
856
857 lpf = lttng_pid_tracker_create();
858 if (!lpf) {
859 ret = -ENOMEM;
860 goto unlock;
861 }
862 ret = lttng_pid_tracker_add(lpf, pid);
863 rcu_assign_pointer(session->pid_tracker, lpf);
864 } else {
865 ret = lttng_pid_tracker_add(session->pid_tracker, pid);
866 }
867 }
868 unlock:
869 mutex_unlock(&sessions_mutex);
870 return ret;
871 }
872
873 int lttng_session_untrack_pid(struct lttng_session *session, int pid)
874 {
875 int ret;
876
877 if (pid < -1)
878 return -EINVAL;
879 mutex_lock(&sessions_mutex);
880 if (pid == -1) {
881 /* untrack all pids: replace by empty tracker. */
882 struct lttng_pid_tracker *old_lpf = session->pid_tracker;
883 struct lttng_pid_tracker *lpf;
884
885 lpf = lttng_pid_tracker_create();
886 if (!lpf) {
887 ret = -ENOMEM;
888 goto unlock;
889 }
890 rcu_assign_pointer(session->pid_tracker, lpf);
891 synchronize_trace();
892 if (old_lpf)
893 lttng_pid_tracker_destroy(old_lpf);
894 ret = 0;
895 } else {
896 if (!session->pid_tracker) {
897 ret = -ENOENT;
898 goto unlock;
899 }
900 ret = lttng_pid_tracker_del(session->pid_tracker, pid);
901 }
902 unlock:
903 mutex_unlock(&sessions_mutex);
904 return ret;
905 }
906
907 static
908 void *pid_list_start(struct seq_file *m, loff_t *pos)
909 {
910 struct lttng_session *session = m->private;
911 struct lttng_pid_tracker *lpf;
912 struct lttng_pid_hash_node *e;
913 int iter = 0, i;
914
915 mutex_lock(&sessions_mutex);
916 lpf = session->pid_tracker;
917 if (lpf) {
918 for (i = 0; i < LTTNG_PID_TABLE_SIZE; i++) {
919 struct hlist_head *head = &lpf->pid_hash[i];
920
921 lttng_hlist_for_each_entry(e, head, hlist) {
922 if (iter++ >= *pos)
923 return e;
924 }
925 }
926 } else {
927 /* PID tracker disabled. */
928 if (iter >= *pos && iter == 0) {
929 return session; /* empty tracker */
930 }
931 iter++;
932 }
933 /* End of list */
934 return NULL;
935 }
936
937 /* Called with sessions_mutex held. */
938 static
939 void *pid_list_next(struct seq_file *m, void *p, loff_t *ppos)
940 {
941 struct lttng_session *session = m->private;
942 struct lttng_pid_tracker *lpf;
943 struct lttng_pid_hash_node *e;
944 int iter = 0, i;
945
946 (*ppos)++;
947 lpf = session->pid_tracker;
948 if (lpf) {
949 for (i = 0; i < LTTNG_PID_TABLE_SIZE; i++) {
950 struct hlist_head *head = &lpf->pid_hash[i];
951
952 lttng_hlist_for_each_entry(e, head, hlist) {
953 if (iter++ >= *ppos)
954 return e;
955 }
956 }
957 } else {
958 /* PID tracker disabled. */
959 if (iter >= *ppos && iter == 0)
960 return session; /* empty tracker */
961 iter++;
962 }
963
964 /* End of list */
965 return NULL;
966 }
967
968 static
969 void pid_list_stop(struct seq_file *m, void *p)
970 {
971 mutex_unlock(&sessions_mutex);
972 }
973
974 static
975 int pid_list_show(struct seq_file *m, void *p)
976 {
977 int pid;
978
979 if (p == m->private) {
980 /* Tracker disabled. */
981 pid = -1;
982 } else {
983 const struct lttng_pid_hash_node *e = p;
984
985 pid = lttng_pid_tracker_get_node_pid(e);
986 }
987 seq_printf(m, "process { pid = %d; };\n", pid);
988 return 0;
989 }
990
991 static
992 const struct seq_operations lttng_tracker_pids_list_seq_ops = {
993 .start = pid_list_start,
994 .next = pid_list_next,
995 .stop = pid_list_stop,
996 .show = pid_list_show,
997 };
998
999 static
1000 int lttng_tracker_pids_list_open(struct inode *inode, struct file *file)
1001 {
1002 return seq_open(file, &lttng_tracker_pids_list_seq_ops);
1003 }
1004
1005 static
1006 int lttng_tracker_pids_list_release(struct inode *inode, struct file *file)
1007 {
1008 struct seq_file *m = file->private_data;
1009 struct lttng_session *session = m->private;
1010 int ret;
1011
1012 WARN_ON_ONCE(!session);
1013 ret = seq_release(inode, file);
1014 if (!ret && session)
1015 fput(session->file);
1016 return ret;
1017 }
1018
1019 const struct file_operations lttng_tracker_pids_list_fops = {
1020 .owner = THIS_MODULE,
1021 .open = lttng_tracker_pids_list_open,
1022 .read = seq_read,
1023 .llseek = seq_lseek,
1024 .release = lttng_tracker_pids_list_release,
1025 };
1026
1027 int lttng_session_list_tracker_pids(struct lttng_session *session)
1028 {
1029 struct file *tracker_pids_list_file;
1030 struct seq_file *m;
1031 int file_fd, ret;
1032
1033 file_fd = lttng_get_unused_fd();
1034 if (file_fd < 0) {
1035 ret = file_fd;
1036 goto fd_error;
1037 }
1038
1039 tracker_pids_list_file = anon_inode_getfile("[lttng_tracker_pids_list]",
1040 &lttng_tracker_pids_list_fops,
1041 NULL, O_RDWR);
1042 if (IS_ERR(tracker_pids_list_file)) {
1043 ret = PTR_ERR(tracker_pids_list_file);
1044 goto file_error;
1045 }
1046 if (atomic_long_add_unless(&session->file->f_count,
1047 1, INT_MAX) == INT_MAX) {
1048 goto refcount_error;
1049 }
1050 ret = lttng_tracker_pids_list_fops.open(NULL, tracker_pids_list_file);
1051 if (ret < 0)
1052 goto open_error;
1053 m = tracker_pids_list_file->private_data;
1054 m->private = session;
1055 fd_install(file_fd, tracker_pids_list_file);
1056
1057 return file_fd;
1058
1059 open_error:
1060 atomic_long_dec(&session->file->f_count);
1061 refcount_error:
1062 fput(tracker_pids_list_file);
1063 file_error:
1064 put_unused_fd(file_fd);
1065 fd_error:
1066 return ret;
1067 }
1068
1069 /*
1070 * Enabler management.
1071 */
1072 static
1073 int lttng_match_enabler_wildcard(const char *desc_name,
1074 const char *name)
1075 {
1076 /* Compare excluding final '*' */
1077 if (strncmp(desc_name, name, strlen(name) - 1))
1078 return 0;
1079 return 1;
1080 }
1081
1082 static
1083 int lttng_match_enabler_name(const char *desc_name,
1084 const char *name)
1085 {
1086 if (strcmp(desc_name, name))
1087 return 0;
1088 return 1;
1089 }
1090
1091 static
1092 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
1093 struct lttng_enabler *enabler)
1094 {
1095 const char *desc_name, *enabler_name;
1096
1097 enabler_name = enabler->event_param.name;
1098 switch (enabler->event_param.instrumentation) {
1099 case LTTNG_KERNEL_TRACEPOINT:
1100 desc_name = desc->name;
1101 break;
1102 case LTTNG_KERNEL_SYSCALL:
1103 desc_name = desc->name;
1104 if (!strncmp(desc_name, "compat_", strlen("compat_")))
1105 desc_name += strlen("compat_");
1106 if (!strncmp(desc_name, "syscall_exit_",
1107 strlen("syscall_exit_"))) {
1108 desc_name += strlen("syscall_exit_");
1109 } else if (!strncmp(desc_name, "syscall_entry_",
1110 strlen("syscall_entry_"))) {
1111 desc_name += strlen("syscall_entry_");
1112 } else {
1113 WARN_ON_ONCE(1);
1114 return -EINVAL;
1115 }
1116 break;
1117 default:
1118 WARN_ON_ONCE(1);
1119 return -EINVAL;
1120 }
1121 switch (enabler->type) {
1122 case LTTNG_ENABLER_WILDCARD:
1123 return lttng_match_enabler_wildcard(desc_name, enabler_name);
1124 case LTTNG_ENABLER_NAME:
1125 return lttng_match_enabler_name(desc_name, enabler_name);
1126 default:
1127 return -EINVAL;
1128 }
1129 }
1130
1131 static
1132 int lttng_event_match_enabler(struct lttng_event *event,
1133 struct lttng_enabler *enabler)
1134 {
1135 if (enabler->event_param.instrumentation != event->instrumentation)
1136 return 0;
1137 if (lttng_desc_match_enabler(event->desc, enabler)
1138 && event->chan == enabler->chan)
1139 return 1;
1140 else
1141 return 0;
1142 }
1143
1144 static
1145 struct lttng_enabler_ref *lttng_event_enabler_ref(struct lttng_event *event,
1146 struct lttng_enabler *enabler)
1147 {
1148 struct lttng_enabler_ref *enabler_ref;
1149
1150 list_for_each_entry(enabler_ref,
1151 &event->enablers_ref_head, node) {
1152 if (enabler_ref->ref == enabler)
1153 return enabler_ref;
1154 }
1155 return NULL;
1156 }
1157
1158 static
1159 void lttng_create_tracepoint_if_missing(struct lttng_enabler *enabler)
1160 {
1161 struct lttng_session *session = enabler->chan->session;
1162 struct lttng_probe_desc *probe_desc;
1163 const struct lttng_event_desc *desc;
1164 int i;
1165 struct list_head *probe_list;
1166
1167 probe_list = lttng_get_probe_list_head();
1168 /*
1169 * For each probe event, if we find that a probe event matches
1170 * our enabler, create an associated lttng_event if not
1171 * already present.
1172 */
1173 list_for_each_entry(probe_desc, probe_list, head) {
1174 for (i = 0; i < probe_desc->nr_events; i++) {
1175 int found = 0;
1176 struct hlist_head *head;
1177 const char *event_name;
1178 size_t name_len;
1179 uint32_t hash;
1180 struct lttng_event *event;
1181
1182 desc = probe_desc->event_desc[i];
1183 if (!lttng_desc_match_enabler(desc, enabler))
1184 continue;
1185 event_name = desc->name;
1186 name_len = strlen(event_name);
1187
1188 /*
1189 * Check if already created.
1190 */
1191 hash = jhash(event_name, name_len, 0);
1192 head = &session->events_ht.table[hash & (LTTNG_EVENT_HT_SIZE - 1)];
1193 lttng_hlist_for_each_entry(event, head, hlist) {
1194 if (event->desc == desc
1195 && event->chan == enabler->chan)
1196 found = 1;
1197 }
1198 if (found)
1199 continue;
1200
1201 /*
1202 * We need to create an event for this
1203 * event probe.
1204 */
1205 event = _lttng_event_create(enabler->chan,
1206 NULL, NULL, desc,
1207 LTTNG_KERNEL_TRACEPOINT);
1208 if (!event) {
1209 printk(KERN_INFO "Unable to create event %s\n",
1210 probe_desc->event_desc[i]->name);
1211 }
1212 }
1213 }
1214 }
1215
1216 static
1217 void lttng_create_syscall_if_missing(struct lttng_enabler *enabler)
1218 {
1219 int ret;
1220
1221 ret = lttng_syscalls_register(enabler->chan, NULL);
1222 WARN_ON_ONCE(ret);
1223 }
1224
1225 /*
1226 * Create struct lttng_event if it is missing and present in the list of
1227 * tracepoint probes.
1228 * Should be called with sessions mutex held.
1229 */
1230 static
1231 void lttng_create_event_if_missing(struct lttng_enabler *enabler)
1232 {
1233 switch (enabler->event_param.instrumentation) {
1234 case LTTNG_KERNEL_TRACEPOINT:
1235 lttng_create_tracepoint_if_missing(enabler);
1236 break;
1237 case LTTNG_KERNEL_SYSCALL:
1238 lttng_create_syscall_if_missing(enabler);
1239 break;
1240 default:
1241 WARN_ON_ONCE(1);
1242 break;
1243 }
1244 }
1245
1246 /*
1247 * Create events associated with an enabler (if not already present),
1248 * and add backward reference from the event to the enabler.
1249 * Should be called with sessions mutex held.
1250 */
1251 static
1252 int lttng_enabler_ref_events(struct lttng_enabler *enabler)
1253 {
1254 struct lttng_session *session = enabler->chan->session;
1255 struct lttng_event *event;
1256
1257 /* First ensure that probe events are created for this enabler. */
1258 lttng_create_event_if_missing(enabler);
1259
1260 /* For each event matching enabler in session event list. */
1261 list_for_each_entry(event, &session->events, list) {
1262 struct lttng_enabler_ref *enabler_ref;
1263
1264 if (!lttng_event_match_enabler(event, enabler))
1265 continue;
1266 enabler_ref = lttng_event_enabler_ref(event, enabler);
1267 if (!enabler_ref) {
1268 /*
1269 * If no backward ref, create it.
1270 * Add backward ref from event to enabler.
1271 */
1272 enabler_ref = kzalloc(sizeof(*enabler_ref), GFP_KERNEL);
1273 if (!enabler_ref)
1274 return -ENOMEM;
1275 enabler_ref->ref = enabler;
1276 list_add(&enabler_ref->node,
1277 &event->enablers_ref_head);
1278 }
1279
1280 /*
1281 * Link filter bytecodes if not linked yet.
1282 */
1283 lttng_enabler_event_link_bytecode(event, enabler);
1284
1285 /* TODO: merge event context. */
1286 }
1287 return 0;
1288 }
1289
1290 /*
1291 * Called at module load: connect the probe on all enablers matching
1292 * this event.
1293 * Called with sessions lock held.
1294 */
1295 int lttng_fix_pending_events(void)
1296 {
1297 struct lttng_session *session;
1298
1299 list_for_each_entry(session, &sessions, list)
1300 lttng_session_lazy_sync_enablers(session);
1301 return 0;
1302 }
1303
1304 struct lttng_enabler *lttng_enabler_create(enum lttng_enabler_type type,
1305 struct lttng_kernel_event *event_param,
1306 struct lttng_channel *chan)
1307 {
1308 struct lttng_enabler *enabler;
1309
1310 enabler = kzalloc(sizeof(*enabler), GFP_KERNEL);
1311 if (!enabler)
1312 return NULL;
1313 enabler->type = type;
1314 INIT_LIST_HEAD(&enabler->filter_bytecode_head);
1315 memcpy(&enabler->event_param, event_param,
1316 sizeof(enabler->event_param));
1317 enabler->chan = chan;
1318 /* ctx left NULL */
1319 enabler->enabled = 0;
1320 enabler->evtype = LTTNG_TYPE_ENABLER;
1321 mutex_lock(&sessions_mutex);
1322 list_add(&enabler->node, &enabler->chan->session->enablers_head);
1323 lttng_session_lazy_sync_enablers(enabler->chan->session);
1324 mutex_unlock(&sessions_mutex);
1325 return enabler;
1326 }
1327
1328 int lttng_enabler_enable(struct lttng_enabler *enabler)
1329 {
1330 mutex_lock(&sessions_mutex);
1331 enabler->enabled = 1;
1332 lttng_session_lazy_sync_enablers(enabler->chan->session);
1333 mutex_unlock(&sessions_mutex);
1334 return 0;
1335 }
1336
1337 int lttng_enabler_disable(struct lttng_enabler *enabler)
1338 {
1339 mutex_lock(&sessions_mutex);
1340 enabler->enabled = 0;
1341 lttng_session_lazy_sync_enablers(enabler->chan->session);
1342 mutex_unlock(&sessions_mutex);
1343 return 0;
1344 }
1345
1346 int lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
1347 struct lttng_kernel_filter_bytecode __user *bytecode)
1348 {
1349 struct lttng_filter_bytecode_node *bytecode_node;
1350 uint32_t bytecode_len;
1351 int ret;
1352
1353 ret = get_user(bytecode_len, &bytecode->len);
1354 if (ret)
1355 return ret;
1356 bytecode_node = kzalloc(sizeof(*bytecode_node) + bytecode_len,
1357 GFP_KERNEL);
1358 if (!bytecode_node)
1359 return -ENOMEM;
1360 ret = copy_from_user(&bytecode_node->bc, bytecode,
1361 sizeof(*bytecode) + bytecode_len);
1362 if (ret)
1363 goto error_free;
1364 bytecode_node->enabler = enabler;
1365 /* Enforce length based on allocated size */
1366 bytecode_node->bc.len = bytecode_len;
1367 list_add_tail(&bytecode_node->node, &enabler->filter_bytecode_head);
1368 lttng_session_lazy_sync_enablers(enabler->chan->session);
1369 return 0;
1370
1371 error_free:
1372 kfree(bytecode_node);
1373 return ret;
1374 }
1375
1376 int lttng_enabler_attach_context(struct lttng_enabler *enabler,
1377 struct lttng_kernel_context *context_param)
1378 {
1379 return -ENOSYS;
1380 }
1381
1382 static
1383 void lttng_enabler_destroy(struct lttng_enabler *enabler)
1384 {
1385 struct lttng_filter_bytecode_node *filter_node, *tmp_filter_node;
1386
1387 /* Destroy filter bytecode */
1388 list_for_each_entry_safe(filter_node, tmp_filter_node,
1389 &enabler->filter_bytecode_head, node) {
1390 kfree(filter_node);
1391 }
1392
1393 /* Destroy contexts */
1394 lttng_destroy_context(enabler->ctx);
1395
1396 list_del(&enabler->node);
1397 kfree(enabler);
1398 }
1399
1400 /*
1401 * lttng_session_sync_enablers should be called just before starting a
1402 * session.
1403 * Should be called with sessions mutex held.
1404 */
1405 static
1406 void lttng_session_sync_enablers(struct lttng_session *session)
1407 {
1408 struct lttng_enabler *enabler;
1409 struct lttng_event *event;
1410
1411 list_for_each_entry(enabler, &session->enablers_head, node)
1412 lttng_enabler_ref_events(enabler);
1413 /*
1414 * For each event, if at least one of its enablers is enabled,
1415 * and its channel and session transient states are enabled, we
1416 * enable the event, else we disable it.
1417 */
1418 list_for_each_entry(event, &session->events, list) {
1419 struct lttng_enabler_ref *enabler_ref;
1420 struct lttng_bytecode_runtime *runtime;
1421 int enabled = 0, has_enablers_without_bytecode = 0;
1422
1423 switch (event->instrumentation) {
1424 case LTTNG_KERNEL_TRACEPOINT:
1425 case LTTNG_KERNEL_SYSCALL:
1426 /* Enable events */
1427 list_for_each_entry(enabler_ref,
1428 &event->enablers_ref_head, node) {
1429 if (enabler_ref->ref->enabled) {
1430 enabled = 1;
1431 break;
1432 }
1433 }
1434 break;
1435 default:
1436 /* Not handled with lazy sync. */
1437 continue;
1438 }
1439 /*
1440 * Enabled state is based on union of enablers, with
1441 * intesection of session and channel transient enable
1442 * states.
1443 */
1444 enabled = enabled && session->tstate && event->chan->tstate;
1445
1446 ACCESS_ONCE(event->enabled) = enabled;
1447 /*
1448 * Sync tracepoint registration with event enabled
1449 * state.
1450 */
1451 if (enabled) {
1452 register_event(event);
1453 } else {
1454 _lttng_event_unregister(event);
1455 }
1456
1457 /* Check if has enablers without bytecode enabled */
1458 list_for_each_entry(enabler_ref,
1459 &event->enablers_ref_head, node) {
1460 if (enabler_ref->ref->enabled
1461 && list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1462 has_enablers_without_bytecode = 1;
1463 break;
1464 }
1465 }
1466 event->has_enablers_without_bytecode =
1467 has_enablers_without_bytecode;
1468
1469 /* Enable filters */
1470 list_for_each_entry(runtime,
1471 &event->bytecode_runtime_head, node)
1472 lttng_filter_sync_state(runtime);
1473 }
1474 }
1475
1476 /*
1477 * Apply enablers to session events, adding events to session if need
1478 * be. It is required after each modification applied to an active
1479 * session, and right before session "start".
1480 * "lazy" sync means we only sync if required.
1481 * Should be called with sessions mutex held.
1482 */
1483 static
1484 void lttng_session_lazy_sync_enablers(struct lttng_session *session)
1485 {
1486 /* We can skip if session is not active */
1487 if (!session->active)
1488 return;
1489 lttng_session_sync_enablers(session);
1490 }
1491
1492 /*
1493 * Serialize at most one packet worth of metadata into a metadata
1494 * channel.
1495 * We grab the metadata cache mutex to get exclusive access to our metadata
1496 * buffer and to the metadata cache. Exclusive access to the metadata buffer
1497 * allows us to do racy operations such as looking for remaining space left in
1498 * packet and write, since mutual exclusion protects us from concurrent writes.
1499 * Mutual exclusion on the metadata cache allow us to read the cache content
1500 * without racing against reallocation of the cache by updates.
1501 * Returns the number of bytes written in the channel, 0 if no data
1502 * was written and a negative value on error.
1503 */
1504 int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
1505 struct channel *chan)
1506 {
1507 struct lib_ring_buffer_ctx ctx;
1508 int ret = 0;
1509 size_t len, reserve_len;
1510
1511 /*
1512 * Ensure we support mutiple get_next / put sequences followed by
1513 * put_next. The metadata cache lock protects reading the metadata
1514 * cache. It can indeed be read concurrently by "get_next_subbuf" and
1515 * "flush" operations on the buffer invoked by different processes.
1516 * Moreover, since the metadata cache memory can be reallocated, we
1517 * need to have exclusive access against updates even though we only
1518 * read it.
1519 */
1520 mutex_lock(&stream->metadata_cache->lock);
1521 WARN_ON(stream->metadata_in < stream->metadata_out);
1522 if (stream->metadata_in != stream->metadata_out)
1523 goto end;
1524
1525 len = stream->metadata_cache->metadata_written -
1526 stream->metadata_in;
1527 if (!len)
1528 goto end;
1529 reserve_len = min_t(size_t,
1530 stream->transport->ops.packet_avail_size(chan),
1531 len);
1532 lib_ring_buffer_ctx_init(&ctx, chan, NULL, reserve_len,
1533 sizeof(char), -1);
1534 /*
1535 * If reservation failed, return an error to the caller.
1536 */
1537 ret = stream->transport->ops.event_reserve(&ctx, 0);
1538 if (ret != 0) {
1539 printk(KERN_WARNING "LTTng: Metadata event reservation failed\n");
1540 goto end;
1541 }
1542 stream->transport->ops.event_write(&ctx,
1543 stream->metadata_cache->data + stream->metadata_in,
1544 reserve_len);
1545 stream->transport->ops.event_commit(&ctx);
1546 stream->metadata_in += reserve_len;
1547 ret = reserve_len;
1548
1549 end:
1550 mutex_unlock(&stream->metadata_cache->lock);
1551 return ret;
1552 }
1553
1554 /*
1555 * Write the metadata to the metadata cache.
1556 * Must be called with sessions_mutex held.
1557 * The metadata cache lock protects us from concurrent read access from
1558 * thread outputting metadata content to ring buffer.
1559 */
1560 int lttng_metadata_printf(struct lttng_session *session,
1561 const char *fmt, ...)
1562 {
1563 char *str;
1564 size_t len;
1565 va_list ap;
1566 struct lttng_metadata_stream *stream;
1567
1568 WARN_ON_ONCE(!ACCESS_ONCE(session->active));
1569
1570 va_start(ap, fmt);
1571 str = kvasprintf(GFP_KERNEL, fmt, ap);
1572 va_end(ap);
1573 if (!str)
1574 return -ENOMEM;
1575
1576 len = strlen(str);
1577 mutex_lock(&session->metadata_cache->lock);
1578 if (session->metadata_cache->metadata_written + len >
1579 session->metadata_cache->cache_alloc) {
1580 char *tmp_cache_realloc;
1581 unsigned int tmp_cache_alloc_size;
1582
1583 tmp_cache_alloc_size = max_t(unsigned int,
1584 session->metadata_cache->cache_alloc + len,
1585 session->metadata_cache->cache_alloc << 1);
1586 tmp_cache_realloc = lttng_vzalloc(tmp_cache_alloc_size);
1587 if (!tmp_cache_realloc)
1588 goto err;
1589 if (session->metadata_cache->data) {
1590 memcpy(tmp_cache_realloc,
1591 session->metadata_cache->data,
1592 session->metadata_cache->cache_alloc);
1593 vfree(session->metadata_cache->data);
1594 }
1595
1596 session->metadata_cache->cache_alloc = tmp_cache_alloc_size;
1597 session->metadata_cache->data = tmp_cache_realloc;
1598 }
1599 memcpy(session->metadata_cache->data +
1600 session->metadata_cache->metadata_written,
1601 str, len);
1602 session->metadata_cache->metadata_written += len;
1603 mutex_unlock(&session->metadata_cache->lock);
1604 kfree(str);
1605
1606 list_for_each_entry(stream, &session->metadata_cache->metadata_stream, list)
1607 wake_up_interruptible(&stream->read_wait);
1608
1609 return 0;
1610
1611 err:
1612 mutex_unlock(&session->metadata_cache->lock);
1613 kfree(str);
1614 return -ENOMEM;
1615 }
1616
1617 /*
1618 * Must be called with sessions_mutex held.
1619 */
1620 static
1621 int _lttng_field_statedump(struct lttng_session *session,
1622 const struct lttng_event_field *field)
1623 {
1624 int ret = 0;
1625
1626 switch (field->type.atype) {
1627 case atype_integer:
1628 ret = lttng_metadata_printf(session,
1629 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
1630 field->type.u.basic.integer.size,
1631 field->type.u.basic.integer.alignment,
1632 field->type.u.basic.integer.signedness,
1633 (field->type.u.basic.integer.encoding == lttng_encode_none)
1634 ? "none"
1635 : (field->type.u.basic.integer.encoding == lttng_encode_UTF8)
1636 ? "UTF8"
1637 : "ASCII",
1638 field->type.u.basic.integer.base,
1639 #ifdef __BIG_ENDIAN
1640 field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
1641 #else
1642 field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
1643 #endif
1644 field->name);
1645 break;
1646 case atype_enum:
1647 ret = lttng_metadata_printf(session,
1648 " %s _%s;\n",
1649 field->type.u.basic.enumeration.name,
1650 field->name);
1651 break;
1652 case atype_array:
1653 {
1654 const struct lttng_basic_type *elem_type;
1655
1656 elem_type = &field->type.u.array.elem_type;
1657 ret = lttng_metadata_printf(session,
1658 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
1659 elem_type->u.basic.integer.size,
1660 elem_type->u.basic.integer.alignment,
1661 elem_type->u.basic.integer.signedness,
1662 (elem_type->u.basic.integer.encoding == lttng_encode_none)
1663 ? "none"
1664 : (elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
1665 ? "UTF8"
1666 : "ASCII",
1667 elem_type->u.basic.integer.base,
1668 #ifdef __BIG_ENDIAN
1669 elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
1670 #else
1671 elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
1672 #endif
1673 field->name, field->type.u.array.length);
1674 break;
1675 }
1676 case atype_sequence:
1677 {
1678 const struct lttng_basic_type *elem_type;
1679 const struct lttng_basic_type *length_type;
1680
1681 elem_type = &field->type.u.sequence.elem_type;
1682 length_type = &field->type.u.sequence.length_type;
1683 ret = lttng_metadata_printf(session,
1684 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
1685 length_type->u.basic.integer.size,
1686 (unsigned int) length_type->u.basic.integer.alignment,
1687 length_type->u.basic.integer.signedness,
1688 (length_type->u.basic.integer.encoding == lttng_encode_none)
1689 ? "none"
1690 : ((length_type->u.basic.integer.encoding == lttng_encode_UTF8)
1691 ? "UTF8"
1692 : "ASCII"),
1693 length_type->u.basic.integer.base,
1694 #ifdef __BIG_ENDIAN
1695 length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
1696 #else
1697 length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
1698 #endif
1699 field->name);
1700 if (ret)
1701 return ret;
1702
1703 ret = lttng_metadata_printf(session,
1704 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
1705 elem_type->u.basic.integer.size,
1706 (unsigned int) elem_type->u.basic.integer.alignment,
1707 elem_type->u.basic.integer.signedness,
1708 (elem_type->u.basic.integer.encoding == lttng_encode_none)
1709 ? "none"
1710 : ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
1711 ? "UTF8"
1712 : "ASCII"),
1713 elem_type->u.basic.integer.base,
1714 #ifdef __BIG_ENDIAN
1715 elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
1716 #else
1717 elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
1718 #endif
1719 field->name,
1720 field->name);
1721 break;
1722 }
1723
1724 case atype_string:
1725 /* Default encoding is UTF8 */
1726 ret = lttng_metadata_printf(session,
1727 " string%s _%s;\n",
1728 field->type.u.basic.string.encoding == lttng_encode_ASCII ?
1729 " { encoding = ASCII; }" : "",
1730 field->name);
1731 break;
1732 default:
1733 WARN_ON_ONCE(1);
1734 return -EINVAL;
1735 }
1736 return ret;
1737 }
1738
1739 static
1740 int _lttng_context_metadata_statedump(struct lttng_session *session,
1741 struct lttng_ctx *ctx)
1742 {
1743 int ret = 0;
1744 int i;
1745
1746 if (!ctx)
1747 return 0;
1748 for (i = 0; i < ctx->nr_fields; i++) {
1749 const struct lttng_ctx_field *field = &ctx->fields[i];
1750
1751 ret = _lttng_field_statedump(session, &field->event_field);
1752 if (ret)
1753 return ret;
1754 }
1755 return ret;
1756 }
1757
1758 static
1759 int _lttng_fields_metadata_statedump(struct lttng_session *session,
1760 struct lttng_event *event)
1761 {
1762 const struct lttng_event_desc *desc = event->desc;
1763 int ret = 0;
1764 int i;
1765
1766 for (i = 0; i < desc->nr_fields; i++) {
1767 const struct lttng_event_field *field = &desc->fields[i];
1768
1769 ret = _lttng_field_statedump(session, field);
1770 if (ret)
1771 return ret;
1772 }
1773 return ret;
1774 }
1775
1776 /*
1777 * Must be called with sessions_mutex held.
1778 */
1779 static
1780 int _lttng_event_metadata_statedump(struct lttng_session *session,
1781 struct lttng_channel *chan,
1782 struct lttng_event *event)
1783 {
1784 int ret = 0;
1785
1786 if (event->metadata_dumped || !ACCESS_ONCE(session->active))
1787 return 0;
1788 if (chan->channel_type == METADATA_CHANNEL)
1789 return 0;
1790
1791 ret = lttng_metadata_printf(session,
1792 "event {\n"
1793 " name = \"%s\";\n"
1794 " id = %u;\n"
1795 " stream_id = %u;\n",
1796 event->desc->name,
1797 event->id,
1798 event->chan->id);
1799 if (ret)
1800 goto end;
1801
1802 if (event->ctx) {
1803 ret = lttng_metadata_printf(session,
1804 " context := struct {\n");
1805 if (ret)
1806 goto end;
1807 }
1808 ret = _lttng_context_metadata_statedump(session, event->ctx);
1809 if (ret)
1810 goto end;
1811 if (event->ctx) {
1812 ret = lttng_metadata_printf(session,
1813 " };\n");
1814 if (ret)
1815 goto end;
1816 }
1817
1818 ret = lttng_metadata_printf(session,
1819 " fields := struct {\n"
1820 );
1821 if (ret)
1822 goto end;
1823
1824 ret = _lttng_fields_metadata_statedump(session, event);
1825 if (ret)
1826 goto end;
1827
1828 /*
1829 * LTTng space reservation can only reserve multiples of the
1830 * byte size.
1831 */
1832 ret = lttng_metadata_printf(session,
1833 " };\n"
1834 "};\n\n");
1835 if (ret)
1836 goto end;
1837
1838 event->metadata_dumped = 1;
1839 end:
1840 return ret;
1841
1842 }
1843
1844 /*
1845 * Must be called with sessions_mutex held.
1846 */
1847 static
1848 int _lttng_channel_metadata_statedump(struct lttng_session *session,
1849 struct lttng_channel *chan)
1850 {
1851 int ret = 0;
1852
1853 if (chan->metadata_dumped || !ACCESS_ONCE(session->active))
1854 return 0;
1855
1856 if (chan->channel_type == METADATA_CHANNEL)
1857 return 0;
1858
1859 WARN_ON_ONCE(!chan->header_type);
1860 ret = lttng_metadata_printf(session,
1861 "stream {\n"
1862 " id = %u;\n"
1863 " event.header := %s;\n"
1864 " packet.context := struct packet_context;\n",
1865 chan->id,
1866 chan->header_type == 1 ? "struct event_header_compact" :
1867 "struct event_header_large");
1868 if (ret)
1869 goto end;
1870
1871 if (chan->ctx) {
1872 ret = lttng_metadata_printf(session,
1873 " event.context := struct {\n");
1874 if (ret)
1875 goto end;
1876 }
1877 ret = _lttng_context_metadata_statedump(session, chan->ctx);
1878 if (ret)
1879 goto end;
1880 if (chan->ctx) {
1881 ret = lttng_metadata_printf(session,
1882 " };\n");
1883 if (ret)
1884 goto end;
1885 }
1886
1887 ret = lttng_metadata_printf(session,
1888 "};\n\n");
1889
1890 chan->metadata_dumped = 1;
1891 end:
1892 return ret;
1893 }
1894
1895 /*
1896 * Must be called with sessions_mutex held.
1897 */
1898 static
1899 int _lttng_stream_packet_context_declare(struct lttng_session *session)
1900 {
1901 return lttng_metadata_printf(session,
1902 "struct packet_context {\n"
1903 " uint64_clock_monotonic_t timestamp_begin;\n"
1904 " uint64_clock_monotonic_t timestamp_end;\n"
1905 " uint64_t content_size;\n"
1906 " uint64_t packet_size;\n"
1907 " unsigned long events_discarded;\n"
1908 " uint32_t cpu_id;\n"
1909 "};\n\n"
1910 );
1911 }
1912
1913 /*
1914 * Compact header:
1915 * id: range: 0 - 30.
1916 * id 31 is reserved to indicate an extended header.
1917 *
1918 * Large header:
1919 * id: range: 0 - 65534.
1920 * id 65535 is reserved to indicate an extended header.
1921 *
1922 * Must be called with sessions_mutex held.
1923 */
1924 static
1925 int _lttng_event_header_declare(struct lttng_session *session)
1926 {
1927 return lttng_metadata_printf(session,
1928 "struct event_header_compact {\n"
1929 " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
1930 " variant <id> {\n"
1931 " struct {\n"
1932 " uint27_clock_monotonic_t timestamp;\n"
1933 " } compact;\n"
1934 " struct {\n"
1935 " uint32_t id;\n"
1936 " uint64_clock_monotonic_t timestamp;\n"
1937 " } extended;\n"
1938 " } v;\n"
1939 "} align(%u);\n"
1940 "\n"
1941 "struct event_header_large {\n"
1942 " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
1943 " variant <id> {\n"
1944 " struct {\n"
1945 " uint32_clock_monotonic_t timestamp;\n"
1946 " } compact;\n"
1947 " struct {\n"
1948 " uint32_t id;\n"
1949 " uint64_clock_monotonic_t timestamp;\n"
1950 " } extended;\n"
1951 " } v;\n"
1952 "} align(%u);\n\n",
1953 lttng_alignof(uint32_t) * CHAR_BIT,
1954 lttng_alignof(uint16_t) * CHAR_BIT
1955 );
1956 }
1957
1958 /*
1959 * Approximation of NTP time of day to clock monotonic correlation,
1960 * taken at start of trace.
1961 * Yes, this is only an approximation. Yes, we can (and will) do better
1962 * in future versions.
1963 * Return 0 if offset is negative. It may happen if the system sets
1964 * the REALTIME clock to 0 after boot.
1965 */
1966 static
1967 uint64_t measure_clock_offset(void)
1968 {
1969 uint64_t monotonic_avg, monotonic[2], realtime;
1970 int64_t offset;
1971 struct timespec rts = { 0, 0 };
1972 unsigned long flags;
1973
1974 /* Disable interrupts to increase correlation precision. */
1975 local_irq_save(flags);
1976 monotonic[0] = trace_clock_read64();
1977 getnstimeofday(&rts);
1978 monotonic[1] = trace_clock_read64();
1979 local_irq_restore(flags);
1980
1981 monotonic_avg = (monotonic[0] + monotonic[1]) >> 1;
1982 realtime = (uint64_t) rts.tv_sec * NSEC_PER_SEC;
1983 realtime += rts.tv_nsec;
1984 offset = (int64_t) realtime - monotonic_avg;
1985 if (offset < 0)
1986 return 0;
1987 return offset;
1988 }
1989
1990 /*
1991 * Output metadata into this session's metadata buffers.
1992 * Must be called with sessions_mutex held.
1993 */
1994 static
1995 int _lttng_session_metadata_statedump(struct lttng_session *session)
1996 {
1997 unsigned char *uuid_c = session->uuid.b;
1998 unsigned char uuid_s[37], clock_uuid_s[BOOT_ID_LEN];
1999 struct lttng_channel *chan;
2000 struct lttng_event *event;
2001 int ret = 0;
2002
2003 if (!ACCESS_ONCE(session->active))
2004 return 0;
2005 if (session->metadata_dumped)
2006 goto skip_session;
2007
2008 snprintf(uuid_s, sizeof(uuid_s),
2009 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
2010 uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
2011 uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
2012 uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
2013 uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
2014
2015 ret = lttng_metadata_printf(session,
2016 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
2017 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
2018 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
2019 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
2020 "typealias integer { size = %u; align = %u; signed = false; } := unsigned long;\n"
2021 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
2022 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
2023 "\n"
2024 "trace {\n"
2025 " major = %u;\n"
2026 " minor = %u;\n"
2027 " uuid = \"%s\";\n"
2028 " byte_order = %s;\n"
2029 " packet.header := struct {\n"
2030 " uint32_t magic;\n"
2031 " uint8_t uuid[16];\n"
2032 " uint32_t stream_id;\n"
2033 " };\n"
2034 "};\n\n",
2035 lttng_alignof(uint8_t) * CHAR_BIT,
2036 lttng_alignof(uint16_t) * CHAR_BIT,
2037 lttng_alignof(uint32_t) * CHAR_BIT,
2038 lttng_alignof(uint64_t) * CHAR_BIT,
2039 sizeof(unsigned long) * CHAR_BIT,
2040 lttng_alignof(unsigned long) * CHAR_BIT,
2041 CTF_SPEC_MAJOR,
2042 CTF_SPEC_MINOR,
2043 uuid_s,
2044 #ifdef __BIG_ENDIAN
2045 "be"
2046 #else
2047 "le"
2048 #endif
2049 );
2050 if (ret)
2051 goto end;
2052
2053 ret = lttng_metadata_printf(session,
2054 "env {\n"
2055 " hostname = \"%s\";\n"
2056 " domain = \"kernel\";\n"
2057 " sysname = \"%s\";\n"
2058 " kernel_release = \"%s\";\n"
2059 " kernel_version = \"%s\";\n"
2060 " tracer_name = \"lttng-modules\";\n"
2061 " tracer_major = %d;\n"
2062 " tracer_minor = %d;\n"
2063 " tracer_patchlevel = %d;\n"
2064 "};\n\n",
2065 current->nsproxy->uts_ns->name.nodename,
2066 utsname()->sysname,
2067 utsname()->release,
2068 utsname()->version,
2069 LTTNG_MODULES_MAJOR_VERSION,
2070 LTTNG_MODULES_MINOR_VERSION,
2071 LTTNG_MODULES_PATCHLEVEL_VERSION
2072 );
2073 if (ret)
2074 goto end;
2075
2076 ret = lttng_metadata_printf(session,
2077 "clock {\n"
2078 " name = %s;\n",
2079 "monotonic"
2080 );
2081 if (ret)
2082 goto end;
2083
2084 if (!trace_clock_uuid(clock_uuid_s)) {
2085 ret = lttng_metadata_printf(session,
2086 " uuid = \"%s\";\n",
2087 clock_uuid_s
2088 );
2089 if (ret)
2090 goto end;
2091 }
2092
2093 ret = lttng_metadata_printf(session,
2094 " description = \"Monotonic Clock\";\n"
2095 " freq = %llu; /* Frequency, in Hz */\n"
2096 " /* clock value offset from Epoch is: offset * (1/freq) */\n"
2097 " offset = %llu;\n"
2098 "};\n\n",
2099 (unsigned long long) trace_clock_freq(),
2100 (unsigned long long) measure_clock_offset()
2101 );
2102 if (ret)
2103 goto end;
2104
2105 ret = lttng_metadata_printf(session,
2106 "typealias integer {\n"
2107 " size = 27; align = 1; signed = false;\n"
2108 " map = clock.monotonic.value;\n"
2109 "} := uint27_clock_monotonic_t;\n"
2110 "\n"
2111 "typealias integer {\n"
2112 " size = 32; align = %u; signed = false;\n"
2113 " map = clock.monotonic.value;\n"
2114 "} := uint32_clock_monotonic_t;\n"
2115 "\n"
2116 "typealias integer {\n"
2117 " size = 64; align = %u; signed = false;\n"
2118 " map = clock.monotonic.value;\n"
2119 "} := uint64_clock_monotonic_t;\n\n",
2120 lttng_alignof(uint32_t) * CHAR_BIT,
2121 lttng_alignof(uint64_t) * CHAR_BIT
2122 );
2123 if (ret)
2124 goto end;
2125
2126 ret = _lttng_stream_packet_context_declare(session);
2127 if (ret)
2128 goto end;
2129
2130 ret = _lttng_event_header_declare(session);
2131 if (ret)
2132 goto end;
2133
2134 skip_session:
2135 list_for_each_entry(chan, &session->chan, list) {
2136 ret = _lttng_channel_metadata_statedump(session, chan);
2137 if (ret)
2138 goto end;
2139 }
2140
2141 list_for_each_entry(event, &session->events, list) {
2142 ret = _lttng_event_metadata_statedump(session, event->chan, event);
2143 if (ret)
2144 goto end;
2145 }
2146 session->metadata_dumped = 1;
2147 end:
2148 return ret;
2149 }
2150
2151 /**
2152 * lttng_transport_register - LTT transport registration
2153 * @transport: transport structure
2154 *
2155 * Registers a transport which can be used as output to extract the data out of
2156 * LTTng. The module calling this registration function must ensure that no
2157 * trap-inducing code will be executed by the transport functions. E.g.
2158 * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
2159 * is made visible to the transport function. This registration acts as a
2160 * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
2161 * after its registration must it synchronize the TLBs.
2162 */
2163 void lttng_transport_register(struct lttng_transport *transport)
2164 {
2165 /*
2166 * Make sure no page fault can be triggered by the module about to be
2167 * registered. We deal with this here so we don't have to call
2168 * vmalloc_sync_all() in each module's init.
2169 */
2170 wrapper_vmalloc_sync_all();
2171
2172 mutex_lock(&sessions_mutex);
2173 list_add_tail(&transport->node, &lttng_transport_list);
2174 mutex_unlock(&sessions_mutex);
2175 }
2176 EXPORT_SYMBOL_GPL(lttng_transport_register);
2177
2178 /**
2179 * lttng_transport_unregister - LTT transport unregistration
2180 * @transport: transport structure
2181 */
2182 void lttng_transport_unregister(struct lttng_transport *transport)
2183 {
2184 mutex_lock(&sessions_mutex);
2185 list_del(&transport->node);
2186 mutex_unlock(&sessions_mutex);
2187 }
2188 EXPORT_SYMBOL_GPL(lttng_transport_unregister);
2189
2190 static int __init lttng_events_init(void)
2191 {
2192 int ret;
2193
2194 ret = wrapper_lttng_fixup_sig(THIS_MODULE);
2195 if (ret)
2196 return ret;
2197 ret = wrapper_get_pfnblock_flags_mask_init();
2198 if (ret)
2199 return ret;
2200 ret = wrapper_get_pageblock_flags_mask_init();
2201 if (ret)
2202 return ret;
2203 ret = lttng_context_init();
2204 if (ret)
2205 return ret;
2206 ret = lttng_tracepoint_init();
2207 if (ret)
2208 goto error_tp;
2209 event_cache = KMEM_CACHE(lttng_event, 0);
2210 if (!event_cache) {
2211 ret = -ENOMEM;
2212 goto error_kmem;
2213 }
2214 ret = lttng_abi_init();
2215 if (ret)
2216 goto error_abi;
2217 ret = lttng_logger_init();
2218 if (ret)
2219 goto error_logger;
2220 return 0;
2221
2222 error_logger:
2223 lttng_abi_exit();
2224 error_abi:
2225 kmem_cache_destroy(event_cache);
2226 error_kmem:
2227 lttng_tracepoint_exit();
2228 error_tp:
2229 lttng_context_exit();
2230 return ret;
2231 }
2232
2233 module_init(lttng_events_init);
2234
2235 static void __exit lttng_events_exit(void)
2236 {
2237 struct lttng_session *session, *tmpsession;
2238
2239 lttng_logger_exit();
2240 lttng_abi_exit();
2241 list_for_each_entry_safe(session, tmpsession, &sessions, list)
2242 lttng_session_destroy(session);
2243 kmem_cache_destroy(event_cache);
2244 lttng_tracepoint_exit();
2245 lttng_context_exit();
2246 }
2247
2248 module_exit(lttng_events_exit);
2249
2250 MODULE_LICENSE("GPL and additional rights");
2251 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
2252 MODULE_DESCRIPTION("LTTng Events");
2253 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
2254 __stringify(LTTNG_MODULES_MINOR_VERSION) "."
2255 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
2256 LTTNG_MODULES_EXTRAVERSION);
LTTng 2.0/0.x modules
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