Fix: userspace probe accessors are not const-correct
[lttng-tools.git] / src / bin / lttng-sessiond / trace-kernel.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
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.
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 *
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.
16 */
17
18 #define _LGPL_SOURCE
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <unistd.h>
23
24 #include <lttng/event.h>
25 #include <lttng/lttng-error.h>
26 #include <lttng/userspace-probe.h>
27 #include <lttng/userspace-probe-internal.h>
28
29 #include <common/common.h>
30 #include <common/defaults.h>
31
32 #include "consumer.h"
33 #include "trace-kernel.h"
34 #include "lttng-sessiond.h"
35 #include "notification-thread-commands.h"
36
37 /*
38 * Find the channel name for the given kernel session.
39 */
40 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
41 char *name, struct ltt_kernel_session *session)
42 {
43 struct ltt_kernel_channel *chan;
44
45 assert(session);
46 assert(name);
47
48 /*
49 * If we receive an empty string for channel name, it means the
50 * default channel name is requested.
51 */
52 if (name[0] == '\0')
53 name = DEFAULT_CHANNEL_NAME;
54
55 DBG("Trying to find channel %s", name);
56
57 cds_list_for_each_entry(chan, &session->channel_list.head, list) {
58 if (strcmp(name, chan->channel->name) == 0) {
59 DBG("Found channel by name %s", name);
60 return chan;
61 }
62 }
63
64 return NULL;
65 }
66
67 /*
68 * Find the event for the given channel.
69 */
70 struct ltt_kernel_event *trace_kernel_find_event(
71 char *name, struct ltt_kernel_channel *channel,
72 enum lttng_event_type type,
73 struct lttng_filter_bytecode *filter)
74 {
75 struct ltt_kernel_event *ev;
76 int found = 0;
77
78 assert(name);
79 assert(channel);
80
81 cds_list_for_each_entry(ev, &channel->events_list.head, list) {
82 if (type != LTTNG_EVENT_ALL && ev->type != type) {
83 continue;
84 }
85 if (strcmp(name, ev->event->name)) {
86 continue;
87 }
88 if ((ev->filter && !filter) || (!ev->filter && filter)) {
89 continue;
90 }
91 if (ev->filter && filter) {
92 if (ev->filter->len != filter->len ||
93 memcmp(ev->filter->data, filter->data,
94 filter->len) != 0) {
95 continue;
96 }
97 }
98 found = 1;
99 break;
100 }
101 if (found) {
102 DBG("Found event %s for channel %s", name,
103 channel->channel->name);
104 return ev;
105 } else {
106 return NULL;
107 }
108 }
109
110 /*
111 * Find the event name for the given channel.
112 */
113 struct ltt_kernel_event *trace_kernel_get_event_by_name(
114 char *name, struct ltt_kernel_channel *channel,
115 enum lttng_event_type type)
116 {
117 struct ltt_kernel_event *ev;
118 int found = 0;
119
120 assert(name);
121 assert(channel);
122
123 cds_list_for_each_entry(ev, &channel->events_list.head, list) {
124 if (type != LTTNG_EVENT_ALL && ev->type != type) {
125 continue;
126 }
127 if (strcmp(name, ev->event->name)) {
128 continue;
129 }
130 found = 1;
131 break;
132 }
133 if (found) {
134 DBG("Found event %s for channel %s", name,
135 channel->channel->name);
136 return ev;
137 } else {
138 return NULL;
139 }
140 }
141
142 /*
143 * Allocate and initialize a kernel session data structure.
144 *
145 * Return pointer to structure or NULL.
146 */
147 struct ltt_kernel_session *trace_kernel_create_session(void)
148 {
149 struct ltt_kernel_session *lks = NULL;
150
151 /* Allocate a new ltt kernel session */
152 lks = zmalloc(sizeof(struct ltt_kernel_session));
153 if (lks == NULL) {
154 PERROR("create kernel session zmalloc");
155 goto alloc_error;
156 }
157
158 /* Init data structure */
159 lks->fd = -1;
160 lks->metadata_stream_fd = -1;
161 lks->channel_count = 0;
162 lks->stream_count_global = 0;
163 lks->metadata = NULL;
164 CDS_INIT_LIST_HEAD(&lks->channel_list.head);
165
166 lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
167 if (lks->consumer == NULL) {
168 goto error;
169 }
170
171 return lks;
172
173 error:
174 free(lks);
175
176 alloc_error:
177 return NULL;
178 }
179
180 /*
181 * Allocate and initialize a kernel channel data structure.
182 *
183 * Return pointer to structure or NULL.
184 */
185 struct ltt_kernel_channel *trace_kernel_create_channel(
186 struct lttng_channel *chan)
187 {
188 struct ltt_kernel_channel *lkc;
189 struct lttng_channel_extended *extended = NULL;
190
191 assert(chan);
192
193 lkc = zmalloc(sizeof(struct ltt_kernel_channel));
194 if (lkc == NULL) {
195 PERROR("ltt_kernel_channel zmalloc");
196 goto error;
197 }
198
199 lkc->channel = zmalloc(sizeof(struct lttng_channel));
200 if (lkc->channel == NULL) {
201 PERROR("lttng_channel zmalloc");
202 goto error;
203 }
204
205 extended = zmalloc(sizeof(struct lttng_channel_extended));
206 if (!extended) {
207 PERROR("lttng_channel_channel zmalloc");
208 goto error;
209 }
210 memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
211 memcpy(extended, chan->attr.extended.ptr, sizeof(struct lttng_channel_extended));
212 lkc->channel->attr.extended.ptr = extended;
213 extended = NULL;
214
215 /*
216 * If we receive an empty string for channel name, it means the
217 * default channel name is requested.
218 */
219 if (chan->name[0] == '\0') {
220 strncpy(lkc->channel->name, DEFAULT_CHANNEL_NAME,
221 sizeof(lkc->channel->name));
222 }
223 lkc->channel->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
224
225 lkc->fd = -1;
226 lkc->stream_count = 0;
227 lkc->event_count = 0;
228 lkc->enabled = 1;
229 lkc->published_to_notification_thread = false;
230 /* Init linked list */
231 CDS_INIT_LIST_HEAD(&lkc->events_list.head);
232 CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
233 CDS_INIT_LIST_HEAD(&lkc->ctx_list);
234
235 return lkc;
236
237 error:
238 if (lkc) {
239 free(lkc->channel);
240 }
241 free(extended);
242 free(lkc);
243 return NULL;
244 }
245
246 /*
247 * Allocate and init a kernel context object.
248 *
249 * Return the allocated object or NULL on error.
250 */
251 struct ltt_kernel_context *trace_kernel_create_context(
252 struct lttng_kernel_context *ctx)
253 {
254 struct ltt_kernel_context *kctx;
255
256 kctx = zmalloc(sizeof(*kctx));
257 if (!kctx) {
258 PERROR("zmalloc kernel context");
259 goto error;
260 }
261
262 if (ctx) {
263 memcpy(&kctx->ctx, ctx, sizeof(kctx->ctx));
264 }
265 error:
266 return kctx;
267 }
268
269 /*
270 * Allocate and init a kernel context object from an existing kernel context
271 * object.
272 *
273 * Return the allocated object or NULL on error.
274 */
275 struct ltt_kernel_context *trace_kernel_copy_context(
276 struct ltt_kernel_context *kctx)
277 {
278 struct ltt_kernel_context *kctx_copy;
279
280 assert(kctx);
281 kctx_copy = zmalloc(sizeof(*kctx_copy));
282 if (!kctx_copy) {
283 PERROR("zmalloc ltt_kernel_context");
284 goto error;
285 }
286
287 memcpy(kctx_copy, kctx, sizeof(*kctx_copy));
288 memset(&kctx_copy->list, 0, sizeof(kctx_copy->list));
289
290 error:
291 return kctx_copy;
292 }
293
294 /*
295 * Allocate and initialize a kernel event. Set name and event type.
296 * We own filter_expression, and filter.
297 *
298 * Return pointer to structure or NULL.
299 */
300 enum lttng_error_code trace_kernel_create_event(
301 struct lttng_event *ev, char *filter_expression,
302 struct lttng_filter_bytecode *filter,
303 struct ltt_kernel_event **kernel_event)
304 {
305 enum lttng_error_code ret;
306 struct lttng_kernel_event *attr;
307 struct ltt_kernel_event *local_kernel_event;
308 struct lttng_userspace_probe_location *userspace_probe_location = NULL;
309
310 assert(ev);
311
312 local_kernel_event = zmalloc(sizeof(struct ltt_kernel_event));
313 attr = zmalloc(sizeof(struct lttng_kernel_event));
314 if (local_kernel_event == NULL || attr == NULL) {
315 PERROR("kernel event zmalloc");
316 ret = LTTNG_ERR_NOMEM;
317 goto error;
318 }
319
320 switch (ev->type) {
321 case LTTNG_EVENT_PROBE:
322 attr->instrumentation = LTTNG_KERNEL_KPROBE;
323 attr->u.kprobe.addr = ev->attr.probe.addr;
324 attr->u.kprobe.offset = ev->attr.probe.offset;
325 strncpy(attr->u.kprobe.symbol_name,
326 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
327 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
328 break;
329 case LTTNG_EVENT_USERSPACE_PROBE:
330 {
331 const struct lttng_userspace_probe_location* location = NULL;
332 const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
333
334 location = lttng_event_get_userspace_probe_location(ev);
335 if (!location) {
336 ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
337 goto error;
338 }
339
340 /*
341 * From this point on, the specific term 'uprobe' is used
342 * instead of the generic 'userspace probe' because it's the
343 * technology used at the moment for this instrumentation.
344 * LTTng currently implements userspace probes using uprobes.
345 * In the interactions with the kernel tracer, we use the
346 * uprobe term.
347 */
348 attr->instrumentation = LTTNG_KERNEL_UPROBE;
349
350 /*
351 * Only the elf lookup method is supported at the moment.
352 */
353 lookup = lttng_userspace_probe_location_get_lookup_method(
354 location);
355 if (!lookup) {
356 ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
357 goto error;
358 }
359
360 /*
361 * From the kernel tracer's perspective, all userspace probe
362 * event types are all the same: a file and an offset.
363 */
364 switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
365 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
366 /* Get the file descriptor on the target binary. */
367 attr->u.uprobe.fd =
368 lttng_userspace_probe_location_function_get_binary_fd(location);
369
370 /*
371 * Save a reference to the probe location used during
372 * the listing of events. Close its FD since it won't
373 * be needed for listing.
374 */
375 userspace_probe_location =
376 lttng_userspace_probe_location_copy(location);
377 ret = lttng_userspace_probe_location_function_set_binary_fd(
378 userspace_probe_location, -1);
379 if (ret) {
380 goto error;
381 }
382 break;
383 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
384 /* Get the file descriptor on the target binary. */
385 attr->u.uprobe.fd =
386 lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
387
388 /*
389 * Save a reference to the probe location used during the listing of
390 * events. Close its FD since it won't be needed for listing.
391 */
392 userspace_probe_location =
393 lttng_userspace_probe_location_copy(location);
394 ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
395 userspace_probe_location, -1);
396 if (ret) {
397 goto error;
398 }
399 break;
400 default:
401 DBG("Unsupported lookup method type");
402 ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
403 goto error;
404 }
405 break;
406 }
407 case LTTNG_EVENT_FUNCTION:
408 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
409 attr->u.kretprobe.addr = ev->attr.probe.addr;
410 attr->u.kretprobe.offset = ev->attr.probe.offset;
411 strncpy(attr->u.kretprobe.symbol_name,
412 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
413 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
414 break;
415 case LTTNG_EVENT_FUNCTION_ENTRY:
416 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
417 strncpy(attr->u.ftrace.symbol_name,
418 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
419 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
420 break;
421 case LTTNG_EVENT_TRACEPOINT:
422 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
423 break;
424 case LTTNG_EVENT_SYSCALL:
425 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
426 break;
427 case LTTNG_EVENT_ALL:
428 attr->instrumentation = LTTNG_KERNEL_ALL;
429 break;
430 default:
431 ERR("Unknown kernel instrumentation type (%d)", ev->type);
432 ret = LTTNG_ERR_INVALID;
433 goto error;
434 }
435
436 /* Copy event name */
437 strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
438 attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
439
440 /* Setting up a kernel event */
441 local_kernel_event->fd = -1;
442 local_kernel_event->event = attr;
443 local_kernel_event->enabled = 1;
444 local_kernel_event->filter_expression = filter_expression;
445 local_kernel_event->filter = filter;
446 local_kernel_event->userspace_probe_location = userspace_probe_location;
447
448 *kernel_event = local_kernel_event;
449
450 return LTTNG_OK;
451
452 error:
453 free(filter_expression);
454 free(filter);
455 free(local_kernel_event);
456 free(attr);
457 return ret;
458 }
459
460 /*
461 * Allocate and initialize a kernel metadata.
462 *
463 * Return pointer to structure or NULL.
464 */
465 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
466 {
467 struct ltt_kernel_metadata *lkm;
468 struct lttng_channel *chan;
469
470 lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
471 chan = zmalloc(sizeof(struct lttng_channel));
472 if (lkm == NULL || chan == NULL) {
473 PERROR("kernel metadata zmalloc");
474 goto error;
475 }
476
477 /* Set default attributes */
478 chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
479 chan->attr.subbuf_size = default_get_metadata_subbuf_size();
480 chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
481 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
482 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
483 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
484
485 /* Init metadata */
486 lkm->fd = -1;
487 lkm->conf = chan;
488
489 return lkm;
490
491 error:
492 free(lkm);
493 free(chan);
494 return NULL;
495 }
496
497 /*
498 * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
499 * default.
500 *
501 * Return pointer to structure or NULL.
502 */
503 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
504 unsigned int count)
505 {
506 int ret;
507 struct ltt_kernel_stream *lks;
508
509 assert(name);
510
511 lks = zmalloc(sizeof(struct ltt_kernel_stream));
512 if (lks == NULL) {
513 PERROR("kernel stream zmalloc");
514 goto error;
515 }
516
517 /* Set name */
518 ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
519 if (ret < 0) {
520 PERROR("snprintf stream name");
521 goto error;
522 }
523 lks->name[sizeof(lks->name) - 1] = '\0';
524
525 /* Init stream */
526 lks->fd = -1;
527 lks->state = 0;
528 lks->cpu = count;
529
530 return lks;
531
532 error:
533 return NULL;
534 }
535
536 /*
537 * Cleanup kernel stream structure.
538 */
539 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
540 {
541 assert(stream);
542
543 DBG("[trace] Closing stream fd %d", stream->fd);
544 /* Close kernel fd */
545 if (stream->fd >= 0) {
546 int ret;
547
548 ret = close(stream->fd);
549 if (ret) {
550 PERROR("close");
551 }
552 }
553 /* Remove from stream list */
554 cds_list_del(&stream->list);
555
556 free(stream);
557 }
558
559 /*
560 * Cleanup kernel event structure.
561 */
562 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
563 {
564 assert(event);
565
566 if (event->fd >= 0) {
567 int ret;
568
569 DBG("[trace] Closing event fd %d", event->fd);
570 /* Close kernel fd */
571 ret = close(event->fd);
572 if (ret) {
573 PERROR("close");
574 }
575 } else {
576 DBG("[trace] Tearing down event (no associated fd)");
577 }
578
579 /* Remove from event list */
580 cds_list_del(&event->list);
581
582 free(event->filter_expression);
583 free(event->filter);
584
585 free(event->event);
586 free(event);
587 }
588
589 /*
590 * Cleanup kernel context structure.
591 */
592 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
593 {
594 assert(ctx);
595
596 if (ctx->in_list) {
597 cds_list_del(&ctx->list);
598 }
599 free(ctx);
600 }
601
602 /*
603 * Cleanup kernel channel structure.
604 */
605 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
606 {
607 struct ltt_kernel_stream *stream, *stmp;
608 struct ltt_kernel_event *event, *etmp;
609 struct ltt_kernel_context *ctx, *ctmp;
610 int ret;
611 enum lttng_error_code status;
612
613 assert(channel);
614
615 DBG("[trace] Closing channel fd %d", channel->fd);
616 /* Close kernel fd */
617 if (channel->fd >= 0) {
618 ret = close(channel->fd);
619 if (ret) {
620 PERROR("close");
621 }
622 }
623
624 /* For each stream in the channel list */
625 cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
626 trace_kernel_destroy_stream(stream);
627 }
628
629 /* For each event in the channel list */
630 cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
631 trace_kernel_destroy_event(event);
632 }
633
634 /* For each context in the channel list */
635 cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
636 trace_kernel_destroy_context(ctx);
637 }
638
639 /* Remove from channel list */
640 cds_list_del(&channel->list);
641
642 if (notification_thread_handle
643 && channel->published_to_notification_thread) {
644 status = notification_thread_command_remove_channel(
645 notification_thread_handle,
646 channel->key, LTTNG_DOMAIN_KERNEL);
647 assert(status == LTTNG_OK);
648 }
649 free(channel->channel->attr.extended.ptr);
650 free(channel->channel);
651 free(channel);
652 }
653
654 /*
655 * Cleanup kernel metadata structure.
656 */
657 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
658 {
659 assert(metadata);
660
661 DBG("[trace] Closing metadata fd %d", metadata->fd);
662 /* Close kernel fd */
663 if (metadata->fd >= 0) {
664 int ret;
665
666 ret = close(metadata->fd);
667 if (ret) {
668 PERROR("close");
669 }
670 }
671
672 free(metadata->conf);
673 free(metadata);
674 }
675
676 /*
677 * Cleanup kernel session structure
678 *
679 * Should *NOT* be called with RCU read-side lock held.
680 */
681 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
682 {
683 struct ltt_kernel_channel *channel, *ctmp;
684 int ret;
685
686 assert(session);
687
688 DBG("[trace] Closing session fd %d", session->fd);
689 /* Close kernel fds */
690 if (session->fd >= 0) {
691 ret = close(session->fd);
692 if (ret) {
693 PERROR("close");
694 }
695 }
696
697 if (session->metadata_stream_fd >= 0) {
698 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
699 ret = close(session->metadata_stream_fd);
700 if (ret) {
701 PERROR("close");
702 }
703 }
704
705 if (session->metadata != NULL) {
706 trace_kernel_destroy_metadata(session->metadata);
707 }
708
709 cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
710 trace_kernel_destroy_channel(channel);
711 }
712
713 /* Wipe consumer output object */
714 consumer_output_put(session->consumer);
715
716 free(session);
717 }
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