Fix RCU-related hangs: incorrect lttng_ht_destroy use
[lttng-tools.git] / src / bin / lttng-sessiond / trace-ust.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 _GNU_SOURCE
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <unistd.h>
23
24 #include <common/common.h>
25 #include <common/defaults.h>
26
27 #include "buffer-registry.h"
28 #include "trace-ust.h"
29
30 /*
31 * Match function for the events hash table lookup.
32 *
33 * Matches by name only. Used by the disable command.
34 */
35 int trace_ust_ht_match_event_by_name(struct cds_lfht_node *node,
36 const void *_key)
37 {
38 struct ltt_ust_event *event;
39 const char *name;
40
41 assert(node);
42 assert(_key);
43
44 event = caa_container_of(node, struct ltt_ust_event, node.node);
45 name = _key;
46
47 /* Event name */
48 if (strncmp(event->attr.name, name, sizeof(event->attr.name)) != 0) {
49 goto no_match;
50 }
51
52 /* Match */
53 return 1;
54
55 no_match:
56 return 0;
57 }
58
59 /*
60 * Match function for the hash table lookup.
61 *
62 * It matches an ust event based on three attributes which are the event name,
63 * the filter bytecode and the loglevel.
64 */
65 int trace_ust_ht_match_event(struct cds_lfht_node *node, const void *_key)
66 {
67 struct ltt_ust_event *event;
68 const struct ltt_ust_ht_key *key;
69
70 assert(node);
71 assert(_key);
72
73 event = caa_container_of(node, struct ltt_ust_event, node.node);
74 key = _key;
75
76 /* Match the 3 elements of the key: name, filter and loglevel. */
77
78 /* Event name */
79 if (strncmp(event->attr.name, key->name, sizeof(event->attr.name)) != 0) {
80 goto no_match;
81 }
82
83 /* Event loglevel. */
84 if (event->attr.loglevel != key->loglevel) {
85 if (event->attr.loglevel_type == LTTNG_UST_LOGLEVEL_ALL
86 && key->loglevel == 0 && event->attr.loglevel == -1) {
87 /*
88 * Match is accepted. This is because on event creation, the
89 * loglevel is set to -1 if the event loglevel type is ALL so 0 and
90 * -1 are accepted for this loglevel type since 0 is the one set by
91 * the API when receiving an enable event.
92 */
93 } else {
94 goto no_match;
95 }
96 }
97
98 /* Only one of the filters is NULL, fail. */
99 if ((key->filter && !event->filter) || (!key->filter && event->filter)) {
100 goto no_match;
101 }
102
103 if (key->filter && event->filter) {
104 /* Both filters exists, check length followed by the bytecode. */
105 if (event->filter->len != key->filter->len ||
106 memcmp(event->filter->data, key->filter->data,
107 event->filter->len) != 0) {
108 goto no_match;
109 }
110 }
111
112 /* Match. */
113 return 1;
114
115 no_match:
116 return 0;
117 }
118
119 /*
120 * Find the channel in the hashtable and return channel pointer. RCU read side
121 * lock MUST be acquired before calling this.
122 */
123 struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
124 char *name)
125 {
126 struct lttng_ht_node_str *node;
127 struct lttng_ht_iter iter;
128
129 lttng_ht_lookup(ht, (void *)name, &iter);
130 node = lttng_ht_iter_get_node_str(&iter);
131 if (node == NULL) {
132 goto error;
133 }
134
135 DBG2("Trace UST channel %s found by name", name);
136
137 return caa_container_of(node, struct ltt_ust_channel, node);
138
139 error:
140 DBG2("Trace UST channel %s not found by name", name);
141 return NULL;
142 }
143
144 /*
145 * Find the event in the hashtable and return event pointer. RCU read side lock
146 * MUST be acquired before calling this.
147 */
148 struct ltt_ust_event *trace_ust_find_event(struct lttng_ht *ht,
149 char *name, struct lttng_filter_bytecode *filter, int loglevel)
150 {
151 struct lttng_ht_node_str *node;
152 struct lttng_ht_iter iter;
153 struct ltt_ust_ht_key key;
154
155 assert(name);
156 assert(ht);
157
158 key.name = name;
159 key.filter = filter;
160 key.loglevel = loglevel;
161
162 cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
163 trace_ust_ht_match_event, &key, &iter.iter);
164 node = lttng_ht_iter_get_node_str(&iter);
165 if (node == NULL) {
166 goto error;
167 }
168
169 DBG2("Trace UST event %s found", key.name);
170
171 return caa_container_of(node, struct ltt_ust_event, node);
172
173 error:
174 DBG2("Trace UST event %s NOT found", key.name);
175 return NULL;
176 }
177
178 /*
179 * Allocate and initialize a ust session data structure.
180 *
181 * Return pointer to structure or NULL.
182 */
183 struct ltt_ust_session *trace_ust_create_session(unsigned int session_id)
184 {
185 struct ltt_ust_session *lus;
186
187 /* Allocate a new ltt ust session */
188 lus = zmalloc(sizeof(struct ltt_ust_session));
189 if (lus == NULL) {
190 PERROR("create ust session zmalloc");
191 goto error;
192 }
193
194 /* Init data structure */
195 lus->id = session_id;
196 lus->start_trace = 0;
197
198 /*
199 * Default buffer type. This can be changed through an enable channel
200 * requesting a different type. Note that this can only be changed once
201 * during the session lifetime which is at the first enable channel and
202 * only before start. The flag buffer_type_changed indicates the status.
203 */
204 lus->buffer_type = LTTNG_BUFFER_PER_PID;
205 /* Once set to 1, the buffer_type is immutable for the session. */
206 lus->buffer_type_changed = 0;
207 /* Init it in case it get used after allocation. */
208 CDS_INIT_LIST_HEAD(&lus->buffer_reg_uid_list);
209
210 /* Alloc UST global domain channels' HT */
211 lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
212
213 lus->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
214 if (lus->consumer == NULL) {
215 goto error_consumer;
216 }
217
218 /*
219 * The tmp_consumer stays NULL until a set_consumer_uri command is
220 * executed. At this point, the consumer should be nullify until an
221 * enable_consumer command. This assignment is symbolic since we've zmalloc
222 * the struct.
223 */
224 lus->tmp_consumer = NULL;
225
226 DBG2("UST trace session create successful");
227
228 return lus;
229
230 error_consumer:
231 lttng_ht_destroy(lus->domain_global.channels);
232 free(lus);
233 error:
234 return NULL;
235 }
236
237 /*
238 * Allocate and initialize a ust channel data structure.
239 *
240 * Return pointer to structure or NULL.
241 */
242 struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan)
243 {
244 struct ltt_ust_channel *luc;
245
246 assert(chan);
247
248 luc = zmalloc(sizeof(struct ltt_ust_channel));
249 if (luc == NULL) {
250 PERROR("ltt_ust_channel zmalloc");
251 goto error;
252 }
253
254 /* Copy UST channel attributes */
255 luc->attr.overwrite = chan->attr.overwrite;
256 luc->attr.subbuf_size = chan->attr.subbuf_size;
257 luc->attr.num_subbuf = chan->attr.num_subbuf;
258 luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
259 luc->attr.read_timer_interval = chan->attr.read_timer_interval;
260 luc->attr.output = (enum lttng_ust_output) chan->attr.output;
261
262 /* Translate to UST output enum */
263 switch (luc->attr.output) {
264 default:
265 luc->attr.output = LTTNG_UST_MMAP;
266 break;
267 }
268
269 /* Copy channel name */
270 strncpy(luc->name, chan->name, sizeof(luc->name));
271 luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
272
273 /* Init node */
274 lttng_ht_node_init_str(&luc->node, luc->name);
275 /* Alloc hash tables */
276 luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
277 luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
278
279 /* On-disk circular buffer parameters */
280 luc->tracefile_size = chan->attr.tracefile_size;
281 luc->tracefile_count = chan->attr.tracefile_count;
282
283 DBG2("Trace UST channel %s created", luc->name);
284
285 error:
286 return luc;
287 }
288
289 /*
290 * Allocate and initialize a ust event. Set name and event type.
291 *
292 * Return pointer to structure or NULL.
293 */
294 struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
295 struct lttng_filter_bytecode *filter)
296 {
297 struct ltt_ust_event *lue;
298
299 assert(ev);
300
301 lue = zmalloc(sizeof(struct ltt_ust_event));
302 if (lue == NULL) {
303 PERROR("ust event zmalloc");
304 goto error;
305 }
306
307 switch (ev->type) {
308 case LTTNG_EVENT_PROBE:
309 lue->attr.instrumentation = LTTNG_UST_PROBE;
310 break;
311 case LTTNG_EVENT_FUNCTION:
312 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
313 break;
314 case LTTNG_EVENT_FUNCTION_ENTRY:
315 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
316 break;
317 case LTTNG_EVENT_TRACEPOINT:
318 lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
319 break;
320 default:
321 ERR("Unknown ust instrumentation type (%d)", ev->type);
322 goto error_free_event;
323 }
324
325 /* Copy event name */
326 strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
327 lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
328
329 switch (ev->loglevel_type) {
330 case LTTNG_EVENT_LOGLEVEL_ALL:
331 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
332 lue->attr.loglevel = -1; /* Force to -1 */
333 break;
334 case LTTNG_EVENT_LOGLEVEL_RANGE:
335 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
336 lue->attr.loglevel = ev->loglevel;
337 break;
338 case LTTNG_EVENT_LOGLEVEL_SINGLE:
339 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
340 lue->attr.loglevel = ev->loglevel;
341 break;
342 default:
343 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
344 goto error_free_event;
345 }
346
347 /* Same layout. */
348 lue->filter = (struct lttng_ust_filter_bytecode *) filter;
349
350 /* Init node */
351 lttng_ht_node_init_str(&lue->node, lue->attr.name);
352
353 DBG2("Trace UST event %s, loglevel (%d,%d) created",
354 lue->attr.name, lue->attr.loglevel_type,
355 lue->attr.loglevel);
356
357 return lue;
358
359 error_free_event:
360 free(lue);
361 error:
362 return NULL;
363 }
364
365 /*
366 * Allocate and initialize a ust metadata.
367 *
368 * Return pointer to structure or NULL.
369 */
370 struct ltt_ust_metadata *trace_ust_create_metadata(char *path)
371 {
372 int ret;
373 struct ltt_ust_metadata *lum;
374
375 assert(path);
376
377 lum = zmalloc(sizeof(struct ltt_ust_metadata));
378 if (lum == NULL) {
379 PERROR("ust metadata zmalloc");
380 goto error;
381 }
382
383 /* Set default attributes */
384 lum->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
385 lum->attr.subbuf_size = default_get_metadata_subbuf_size();
386 lum->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
387 lum->attr.switch_timer_interval = DEFAULT_UST_CHANNEL_SWITCH_TIMER;
388 lum->attr.read_timer_interval = DEFAULT_UST_CHANNEL_READ_TIMER;
389 lum->attr.output = LTTNG_UST_MMAP;
390
391 lum->handle = -1;
392 /* Set metadata trace path */
393 ret = snprintf(lum->pathname, PATH_MAX, "%s/" DEFAULT_METADATA_NAME, path);
394 if (ret < 0) {
395 PERROR("asprintf ust metadata");
396 goto error_free_metadata;
397 }
398
399 return lum;
400
401 error_free_metadata:
402 free(lum);
403 error:
404 return NULL;
405 }
406
407 /*
408 * Allocate and initialize an UST context.
409 *
410 * Return pointer to structure or NULL.
411 */
412 struct ltt_ust_context *trace_ust_create_context(
413 struct lttng_event_context *ctx)
414 {
415 struct ltt_ust_context *uctx;
416 enum lttng_ust_context_type utype;
417
418 assert(ctx);
419
420 switch (ctx->ctx) {
421 case LTTNG_EVENT_CONTEXT_VTID:
422 utype = LTTNG_UST_CONTEXT_VTID;
423 break;
424 case LTTNG_EVENT_CONTEXT_VPID:
425 utype = LTTNG_UST_CONTEXT_VPID;
426 break;
427 case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
428 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
429 break;
430 case LTTNG_EVENT_CONTEXT_PROCNAME:
431 utype = LTTNG_UST_CONTEXT_PROCNAME;
432 break;
433 default:
434 ERR("Invalid UST context");
435 return NULL;
436 }
437
438 uctx = zmalloc(sizeof(struct ltt_ust_context));
439 if (uctx == NULL) {
440 PERROR("zmalloc ltt_ust_context");
441 goto error;
442 }
443
444 uctx->ctx.ctx = utype;
445 lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
446
447 return uctx;
448
449 error:
450 return NULL;
451 }
452
453 /*
454 * RCU safe free context structure.
455 */
456 static void destroy_context_rcu(struct rcu_head *head)
457 {
458 struct lttng_ht_node_ulong *node =
459 caa_container_of(head, struct lttng_ht_node_ulong, head);
460 struct ltt_ust_context *ctx =
461 caa_container_of(node, struct ltt_ust_context, node);
462
463 free(ctx);
464 }
465
466 /*
467 * Cleanup UST context hash table.
468 */
469 static void destroy_contexts(struct lttng_ht *ht)
470 {
471 int ret;
472 struct lttng_ht_node_ulong *node;
473 struct lttng_ht_iter iter;
474
475 assert(ht);
476
477 rcu_read_lock();
478 cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
479 ret = lttng_ht_del(ht, &iter);
480 if (!ret) {
481 call_rcu(&node->head, destroy_context_rcu);
482 }
483 }
484 rcu_read_unlock();
485
486 lttng_ht_destroy(ht);
487 }
488
489 /*
490 * Cleanup ust event structure.
491 */
492 void trace_ust_destroy_event(struct ltt_ust_event *event)
493 {
494 assert(event);
495
496 DBG2("Trace destroy UST event %s", event->attr.name);
497 free(event->filter);
498 free(event);
499 }
500
501 /*
502 * URCU intermediate call to complete destroy event.
503 */
504 static void destroy_event_rcu(struct rcu_head *head)
505 {
506 struct lttng_ht_node_str *node =
507 caa_container_of(head, struct lttng_ht_node_str, head);
508 struct ltt_ust_event *event =
509 caa_container_of(node, struct ltt_ust_event, node);
510
511 trace_ust_destroy_event(event);
512 }
513
514 /*
515 * Cleanup UST events hashtable.
516 */
517 static void destroy_events(struct lttng_ht *events)
518 {
519 int ret;
520 struct lttng_ht_node_str *node;
521 struct lttng_ht_iter iter;
522
523 assert(events);
524
525 rcu_read_lock();
526 cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
527 ret = lttng_ht_del(events, &iter);
528 assert(!ret);
529 call_rcu(&node->head, destroy_event_rcu);
530 }
531 rcu_read_unlock();
532
533 lttng_ht_destroy(events);
534 }
535
536 /*
537 * Cleanup ust channel structure.
538 *
539 * Should _NOT_ be called with RCU read lock held.
540 */
541 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
542 {
543 assert(channel);
544
545 DBG2("Trace destroy UST channel %s", channel->name);
546
547 /* Destroying all events of the channel */
548 destroy_events(channel->events);
549 /* Destroying all context of the channel */
550 destroy_contexts(channel->ctx);
551
552 free(channel);
553 }
554
555 /*
556 * URCU intermediate call to complete destroy channel.
557 */
558 static void destroy_channel_rcu(struct rcu_head *head)
559 {
560 struct lttng_ht_node_str *node =
561 caa_container_of(head, struct lttng_ht_node_str, head);
562 struct ltt_ust_channel *channel =
563 caa_container_of(node, struct ltt_ust_channel, node);
564
565 _trace_ust_destroy_channel(channel);
566 }
567
568 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
569 {
570 call_rcu(&channel->node.head, destroy_channel_rcu);
571 }
572
573 /*
574 * Cleanup ust metadata structure.
575 */
576 void trace_ust_destroy_metadata(struct ltt_ust_metadata *metadata)
577 {
578 assert(metadata);
579
580 if (!metadata->handle) {
581 return;
582 }
583 DBG2("Trace UST destroy metadata %d", metadata->handle);
584 free(metadata);
585 }
586
587 /*
588 * Iterate over a hash table containing channels and cleanup safely.
589 */
590 static void destroy_channels(struct lttng_ht *channels)
591 {
592 int ret;
593 struct lttng_ht_node_str *node;
594 struct lttng_ht_iter iter;
595
596 assert(channels);
597
598 rcu_read_lock();
599
600 cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
601 ret = lttng_ht_del(channels, &iter);
602 assert(!ret);
603 call_rcu(&node->head, destroy_channel_rcu);
604 }
605 rcu_read_unlock();
606
607 lttng_ht_destroy(channels);
608 }
609
610 /*
611 * Cleanup UST global domain.
612 */
613 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
614 {
615 assert(dom);
616
617 destroy_channels(dom->channels);
618 }
619
620 /*
621 * Cleanup ust session structure
622 *
623 * Should *NOT* be called with RCU read-side lock held.
624 */
625 void trace_ust_destroy_session(struct ltt_ust_session *session)
626 {
627 struct buffer_reg_uid *reg, *sreg;
628
629 assert(session);
630
631 DBG2("Trace UST destroy session %u", session->id);
632
633 /* Cleaning up UST domain */
634 destroy_domain_global(&session->domain_global);
635
636 /* Cleanup UID buffer registry object(s). */
637 cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
638 lnode) {
639 cds_list_del(&reg->lnode);
640 buffer_reg_uid_remove(reg);
641 buffer_reg_uid_destroy(reg, session->consumer);
642 }
643
644 consumer_destroy_output(session->consumer);
645 consumer_destroy_output(session->tmp_consumer);
646
647 free(session);
648 }
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