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8020ceb5 MD |
1 | /* |
2 | * ltt-events.c | |
3 | * | |
4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Holds LTTng per-session event registry. | |
7 | * | |
8 | * Dual LGPL v2.1/GPL v2 license. | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/list.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/jiffies.h> | |
17 | #include <linux/uuid.h> | |
18 | #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ | |
19 | #include "ltt-events.h" | |
20 | #include "ltt-tracer.h" | |
21 | ||
22 | static LIST_HEAD(sessions); | |
23 | static LIST_HEAD(ltt_transport_list); | |
24 | static DEFINE_MUTEX(sessions_mutex); | |
25 | static struct kmem_cache *event_cache; | |
26 | ||
27 | static void _ltt_event_destroy(struct ltt_event *event); | |
28 | static void _ltt_channel_destroy(struct ltt_channel *chan); | |
29 | static int _ltt_event_unregister(struct ltt_event *event); | |
30 | static | |
31 | int _ltt_event_metadata_statedump(struct ltt_session *session, | |
32 | struct ltt_channel *chan, | |
33 | struct ltt_event *event); | |
34 | static | |
35 | int _ltt_session_metadata_statedump(struct ltt_session *session); | |
36 | ||
37 | ||
38 | static | |
39 | void synchronize_trace(void) | |
40 | { | |
41 | synchronize_sched(); | |
42 | #ifdef CONFIG_PREEMPT_RT | |
43 | synchronize_rcu(); | |
44 | #endif | |
45 | } | |
46 | ||
47 | struct ltt_session *ltt_session_create(void) | |
48 | { | |
49 | struct ltt_session *session; | |
50 | ||
51 | mutex_lock(&sessions_mutex); | |
52 | session = kzalloc(sizeof(struct ltt_session), GFP_KERNEL); | |
53 | if (!session) | |
54 | return NULL; | |
55 | INIT_LIST_HEAD(&session->chan); | |
56 | INIT_LIST_HEAD(&session->events); | |
57 | uuid_le_gen(&session->uuid); | |
58 | list_add(&session->list, &sessions); | |
59 | mutex_unlock(&sessions_mutex); | |
60 | return session; | |
61 | } | |
62 | ||
63 | void ltt_session_destroy(struct ltt_session *session) | |
64 | { | |
65 | struct ltt_channel *chan, *tmpchan; | |
66 | struct ltt_event *event, *tmpevent; | |
67 | int ret; | |
68 | ||
69 | mutex_lock(&sessions_mutex); | |
70 | ACCESS_ONCE(session->active) = 0; | |
71 | list_for_each_entry(event, &session->events, list) { | |
72 | ret = _ltt_event_unregister(event); | |
73 | WARN_ON(ret); | |
74 | } | |
75 | synchronize_trace(); /* Wait for in-flight events to complete */ | |
76 | list_for_each_entry_safe(event, tmpevent, &session->events, list) | |
77 | _ltt_event_destroy(event); | |
78 | list_for_each_entry_safe(chan, tmpchan, &session->chan, list) | |
79 | _ltt_channel_destroy(chan); | |
80 | list_del(&session->list); | |
81 | mutex_unlock(&sessions_mutex); | |
82 | kfree(session); | |
83 | } | |
84 | ||
976fe9ea | 85 | int ltt_session_enable(struct ltt_session *session) |
8020ceb5 MD |
86 | { |
87 | int ret = 0; | |
88 | struct ltt_channel *chan; | |
89 | ||
90 | mutex_lock(&sessions_mutex); | |
91 | if (session->active) { | |
92 | ret = -EBUSY; | |
93 | goto end; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Snapshot the number of events per channel to know the type of header | |
98 | * we need to use. | |
99 | */ | |
100 | list_for_each_entry(chan, &session->chan, list) { | |
101 | if (chan->header_type) | |
102 | continue; /* don't change it if session stop/restart */ | |
103 | if (chan->free_event_id < 31) | |
104 | chan->header_type = 1; /* compact */ | |
105 | else | |
106 | chan->header_type = 2; /* large */ | |
107 | } | |
108 | ||
109 | ACCESS_ONCE(session->active) = 1; | |
110 | ACCESS_ONCE(session->been_active) = 1; | |
111 | synchronize_trace(); /* Wait for in-flight events to complete */ | |
112 | ret = _ltt_session_metadata_statedump(session); | |
113 | if (ret) { | |
114 | ACCESS_ONCE(session->active) = 0; | |
115 | synchronize_trace(); /* Wait for in-flight events to complete */ | |
116 | } | |
117 | end: | |
118 | mutex_unlock(&sessions_mutex); | |
119 | return ret; | |
120 | } | |
121 | ||
976fe9ea | 122 | int ltt_session_disable(struct ltt_session *session) |
8020ceb5 MD |
123 | { |
124 | int ret = 0; | |
125 | ||
126 | mutex_lock(&sessions_mutex); | |
127 | if (!session->active) { | |
128 | ret = -EBUSY; | |
129 | goto end; | |
130 | } | |
131 | ACCESS_ONCE(session->active) = 0; | |
132 | synchronize_trace(); /* Wait for in-flight events to complete */ | |
133 | end: | |
134 | mutex_unlock(&sessions_mutex); | |
135 | return ret; | |
136 | } | |
137 | ||
976fe9ea MD |
138 | int ltt_channel_enable(struct ltt_channel *channel) |
139 | { | |
140 | int old; | |
141 | ||
9beb36ba MD |
142 | if (channel == channel->session->metadata) |
143 | return -EPERM; | |
976fe9ea MD |
144 | old = xchg(&channel->enabled, 1); |
145 | if (old) | |
146 | return -EEXIST; | |
147 | return 0; | |
148 | } | |
149 | ||
150 | int ltt_channel_disable(struct ltt_channel *channel) | |
151 | { | |
152 | int old; | |
153 | ||
9beb36ba MD |
154 | if (channel == channel->session->metadata) |
155 | return -EPERM; | |
976fe9ea MD |
156 | old = xchg(&channel->enabled, 0); |
157 | if (!old) | |
158 | return -EEXIST; | |
159 | return 0; | |
160 | } | |
161 | ||
162 | int ltt_event_enable(struct ltt_event *event) | |
163 | { | |
164 | int old; | |
165 | ||
9beb36ba MD |
166 | if (event->chan == event->chan->session->metadata) |
167 | return -EPERM; | |
976fe9ea MD |
168 | old = xchg(&event->enabled, 1); |
169 | if (old) | |
170 | return -EEXIST; | |
171 | return 0; | |
172 | } | |
173 | ||
174 | int ltt_event_disable(struct ltt_event *event) | |
175 | { | |
176 | int old; | |
177 | ||
9beb36ba MD |
178 | if (event->chan == event->chan->session->metadata) |
179 | return -EPERM; | |
976fe9ea MD |
180 | old = xchg(&event->enabled, 0); |
181 | if (!old) | |
182 | return -EEXIST; | |
183 | return 0; | |
184 | } | |
185 | ||
8020ceb5 MD |
186 | static struct ltt_transport *ltt_transport_find(const char *name) |
187 | { | |
188 | struct ltt_transport *transport; | |
189 | ||
190 | list_for_each_entry(transport, <t_transport_list, node) { | |
191 | if (!strcmp(transport->name, name)) | |
192 | return transport; | |
193 | } | |
194 | return NULL; | |
195 | } | |
196 | ||
197 | struct ltt_channel *ltt_channel_create(struct ltt_session *session, | |
198 | const char *transport_name, | |
199 | void *buf_addr, | |
200 | size_t subbuf_size, size_t num_subbuf, | |
201 | unsigned int switch_timer_interval, | |
202 | unsigned int read_timer_interval) | |
203 | { | |
204 | struct ltt_channel *chan; | |
205 | struct ltt_transport *transport; | |
206 | ||
207 | mutex_lock(&sessions_mutex); | |
208 | if (session->been_active) | |
209 | goto active; /* Refuse to add channel to active session */ | |
210 | transport = ltt_transport_find(transport_name); | |
211 | if (!transport) { | |
212 | printk(KERN_WARNING "LTTng transport %s not found\n", | |
213 | transport_name); | |
214 | goto notransport; | |
215 | } | |
216 | chan = kzalloc(sizeof(struct ltt_channel), GFP_KERNEL); | |
217 | if (!chan) | |
218 | goto nomem; | |
219 | chan->session = session; | |
220 | chan->id = session->free_chan_id++; | |
221 | /* | |
222 | * Note: the channel creation op already writes into the packet | |
223 | * headers. Therefore the "chan" information used as input | |
224 | * should be already accessible. | |
225 | */ | |
226 | chan->chan = transport->ops.channel_create("[lttng]", chan, buf_addr, | |
227 | subbuf_size, num_subbuf, switch_timer_interval, | |
228 | read_timer_interval); | |
229 | if (!chan->chan) | |
230 | goto create_error; | |
976fe9ea | 231 | chan->enabled = 1; |
8020ceb5 MD |
232 | chan->ops = &transport->ops; |
233 | list_add(&chan->list, &session->chan); | |
234 | mutex_unlock(&sessions_mutex); | |
235 | return chan; | |
236 | ||
237 | create_error: | |
238 | kfree(chan); | |
239 | nomem: | |
240 | notransport: | |
241 | active: | |
242 | mutex_unlock(&sessions_mutex); | |
243 | return NULL; | |
244 | } | |
245 | ||
246 | /* | |
247 | * Only used internally at session destruction. | |
248 | */ | |
249 | static | |
250 | void _ltt_channel_destroy(struct ltt_channel *chan) | |
251 | { | |
252 | chan->ops->channel_destroy(chan->chan); | |
253 | list_del(&chan->list); | |
254 | lttng_destroy_context(chan->ctx); | |
255 | kfree(chan); | |
256 | } | |
257 | ||
258 | /* | |
259 | * Supports event creation while tracing session is active. | |
260 | */ | |
261 | struct ltt_event *ltt_event_create(struct ltt_channel *chan, | |
262 | struct lttng_kernel_event *event_param, | |
263 | void *filter) | |
264 | { | |
265 | struct ltt_event *event; | |
266 | int ret; | |
267 | ||
268 | mutex_lock(&sessions_mutex); | |
269 | if (chan->free_event_id == -1UL) | |
270 | goto full; | |
271 | /* | |
272 | * This is O(n^2) (for each event, the loop is called at event | |
273 | * creation). Might require a hash if we have lots of events. | |
274 | */ | |
275 | list_for_each_entry(event, &chan->session->events, list) | |
276 | if (!strcmp(event->desc->name, event_param->name)) | |
277 | goto exist; | |
278 | event = kmem_cache_zalloc(event_cache, GFP_KERNEL); | |
279 | if (!event) | |
280 | goto cache_error; | |
281 | event->chan = chan; | |
282 | event->filter = filter; | |
283 | event->id = chan->free_event_id++; | |
976fe9ea | 284 | event->enabled = 1; |
8020ceb5 MD |
285 | event->instrumentation = event_param->instrumentation; |
286 | /* Populate ltt_event structure before tracepoint registration. */ | |
287 | smp_wmb(); | |
288 | switch (event_param->instrumentation) { | |
289 | case LTTNG_KERNEL_TRACEPOINT: | |
290 | event->desc = ltt_event_get(event_param->name); | |
291 | if (!event->desc) | |
292 | goto register_error; | |
293 | ret = tracepoint_probe_register(event_param->name, | |
294 | event->desc->probe_callback, | |
295 | event); | |
296 | if (ret) | |
297 | goto register_error; | |
298 | break; | |
299 | case LTTNG_KERNEL_KPROBE: | |
300 | ret = lttng_kprobes_register(event_param->name, | |
301 | event_param->u.kprobe.symbol_name, | |
302 | event_param->u.kprobe.offset, | |
303 | event_param->u.kprobe.addr, | |
304 | event); | |
305 | if (ret) | |
306 | goto register_error; | |
307 | ret = try_module_get(event->desc->owner); | |
308 | WARN_ON_ONCE(!ret); | |
309 | break; | |
310 | case LTTNG_KERNEL_FUNCTION: | |
311 | ret = lttng_ftrace_register(event_param->name, | |
312 | event_param->u.ftrace.symbol_name, | |
313 | event); | |
314 | if (ret) | |
315 | goto register_error; | |
316 | ret = try_module_get(event->desc->owner); | |
317 | WARN_ON_ONCE(!ret); | |
318 | break; | |
319 | default: | |
320 | WARN_ON_ONCE(1); | |
321 | } | |
322 | ret = _ltt_event_metadata_statedump(chan->session, chan, event); | |
323 | if (ret) | |
324 | goto statedump_error; | |
325 | list_add(&event->list, &chan->session->events); | |
326 | mutex_unlock(&sessions_mutex); | |
327 | return event; | |
328 | ||
329 | statedump_error: | |
330 | WARN_ON_ONCE(tracepoint_probe_unregister(event_param->name, | |
331 | event->desc->probe_callback, | |
332 | event)); | |
333 | ltt_event_put(event->desc); | |
334 | register_error: | |
335 | kmem_cache_free(event_cache, event); | |
336 | cache_error: | |
337 | exist: | |
338 | full: | |
339 | mutex_unlock(&sessions_mutex); | |
340 | return NULL; | |
341 | } | |
342 | ||
343 | /* | |
344 | * Only used internally at session destruction. | |
345 | */ | |
346 | int _ltt_event_unregister(struct ltt_event *event) | |
347 | { | |
348 | int ret = -EINVAL; | |
349 | ||
350 | switch (event->instrumentation) { | |
351 | case LTTNG_KERNEL_TRACEPOINT: | |
352 | ret = tracepoint_probe_unregister(event->desc->name, | |
353 | event->desc->probe_callback, | |
354 | event); | |
355 | if (ret) | |
356 | return ret; | |
357 | break; | |
358 | case LTTNG_KERNEL_KPROBE: | |
359 | lttng_kprobes_unregister(event); | |
360 | ret = 0; | |
361 | break; | |
362 | case LTTNG_KERNEL_FUNCTION: | |
363 | lttng_ftrace_unregister(event); | |
364 | ret = 0; | |
365 | break; | |
366 | default: | |
367 | WARN_ON_ONCE(1); | |
368 | } | |
369 | return ret; | |
370 | } | |
371 | ||
372 | /* | |
373 | * Only used internally at session destruction. | |
374 | */ | |
375 | static | |
376 | void _ltt_event_destroy(struct ltt_event *event) | |
377 | { | |
378 | switch (event->instrumentation) { | |
379 | case LTTNG_KERNEL_TRACEPOINT: | |
380 | ltt_event_put(event->desc); | |
381 | break; | |
382 | case LTTNG_KERNEL_KPROBE: | |
383 | module_put(event->desc->owner); | |
384 | lttng_kprobes_destroy_private(event); | |
385 | break; | |
386 | case LTTNG_KERNEL_FUNCTION: | |
387 | module_put(event->desc->owner); | |
388 | lttng_ftrace_destroy_private(event); | |
389 | break; | |
390 | default: | |
391 | WARN_ON_ONCE(1); | |
392 | } | |
393 | list_del(&event->list); | |
394 | lttng_destroy_context(event->ctx); | |
395 | kmem_cache_free(event_cache, event); | |
396 | } | |
397 | ||
398 | /* | |
399 | * We have exclusive access to our metadata buffer (protected by the | |
400 | * sessions_mutex), so we can do racy operations such as looking for | |
401 | * remaining space left in packet and write, since mutual exclusion | |
402 | * protects us from concurrent writes. | |
403 | */ | |
404 | int lttng_metadata_printf(struct ltt_session *session, | |
405 | const char *fmt, ...) | |
406 | { | |
407 | struct lib_ring_buffer_ctx ctx; | |
408 | struct ltt_channel *chan = session->metadata; | |
409 | char *str; | |
410 | int ret = 0, waitret; | |
411 | size_t len, reserve_len, pos; | |
412 | va_list ap; | |
413 | ||
414 | WARN_ON_ONCE(!ACCESS_ONCE(session->active)); | |
415 | ||
416 | va_start(ap, fmt); | |
417 | str = kvasprintf(GFP_KERNEL, fmt, ap); | |
418 | va_end(ap); | |
419 | if (!str) | |
420 | return -ENOMEM; | |
421 | ||
422 | len = strlen(str); | |
423 | pos = 0; | |
424 | ||
425 | for (pos = 0; pos < len; pos += reserve_len) { | |
426 | reserve_len = min_t(size_t, | |
427 | chan->ops->packet_avail_size(chan->chan), | |
428 | len - pos); | |
429 | lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len, | |
430 | sizeof(char), -1); | |
431 | /* | |
432 | * We don't care about metadata buffer's records lost | |
433 | * count, because we always retry here. Report error if | |
434 | * we need to bail out after timeout or being | |
435 | * interrupted. | |
436 | */ | |
437 | waitret = wait_event_interruptible_timeout(*chan->ops->get_reader_wait_queue(chan->chan), | |
438 | ({ | |
439 | ret = chan->ops->event_reserve(&ctx, 0); | |
440 | ret != -ENOBUFS || !ret; | |
441 | }), | |
442 | msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC)); | |
443 | if (!waitret || waitret == -ERESTARTSYS || ret) { | |
444 | printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n", | |
445 | waitret == -ERESTARTSYS ? "interrupted" : | |
446 | (ret == -ENOBUFS ? "timeout" : "I/O error")); | |
447 | if (waitret == -ERESTARTSYS) | |
448 | ret = waitret; | |
449 | goto end; | |
450 | } | |
451 | chan->ops->event_write(&ctx, &str[pos], reserve_len); | |
452 | chan->ops->event_commit(&ctx); | |
453 | } | |
454 | end: | |
455 | kfree(str); | |
456 | return ret; | |
457 | } | |
458 | ||
459 | static | |
460 | int _ltt_field_statedump(struct ltt_session *session, | |
461 | const struct lttng_event_field *field) | |
462 | { | |
463 | int ret = 0; | |
464 | ||
465 | switch (field->type.atype) { | |
466 | case atype_integer: | |
467 | ret = lttng_metadata_printf(session, | |
468 | " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } %s;\n", | |
469 | field->type.u.basic.integer.size, | |
470 | field->type.u.basic.integer.alignment, | |
471 | field->type.u.basic.integer.signedness, | |
472 | (field->type.u.basic.integer.encoding == lttng_encode_none) | |
473 | ? "none" | |
474 | : (field->type.u.basic.integer.encoding == lttng_encode_UTF8) | |
475 | ? "UTF8" | |
476 | : "ASCII", | |
477 | field->type.u.basic.integer.base, | |
478 | #ifdef __BIG_ENDIAN | |
479 | field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "", | |
480 | #else | |
481 | field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "", | |
482 | #endif | |
483 | field->name); | |
484 | break; | |
485 | case atype_enum: | |
486 | ret = lttng_metadata_printf(session, | |
487 | " %s %s;\n", | |
488 | field->type.u.basic.enumeration.name, | |
489 | field->name); | |
490 | break; | |
491 | case atype_array: | |
492 | { | |
493 | const struct lttng_basic_type *elem_type; | |
494 | ||
495 | elem_type = &field->type.u.array.elem_type; | |
496 | ret = lttng_metadata_printf(session, | |
497 | " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } %s[%u];\n", | |
498 | elem_type->u.basic.integer.size, | |
499 | elem_type->u.basic.integer.alignment, | |
500 | elem_type->u.basic.integer.signedness, | |
501 | (elem_type->u.basic.integer.encoding == lttng_encode_none) | |
502 | ? "none" | |
503 | : (elem_type->u.basic.integer.encoding == lttng_encode_UTF8) | |
504 | ? "UTF8" | |
505 | : "ASCII", | |
506 | elem_type->u.basic.integer.base, | |
507 | #ifdef __BIG_ENDIAN | |
508 | elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "", | |
509 | #else | |
510 | elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "", | |
511 | #endif | |
512 | field->name, field->type.u.array.length); | |
513 | break; | |
514 | } | |
515 | case atype_sequence: | |
516 | { | |
517 | const struct lttng_basic_type *elem_type; | |
518 | const struct lttng_basic_type *length_type; | |
519 | ||
520 | elem_type = &field->type.u.sequence.elem_type; | |
521 | length_type = &field->type.u.sequence.length_type; | |
522 | ret = lttng_metadata_printf(session, | |
523 | " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n", | |
524 | length_type->u.basic.integer.size, | |
525 | (unsigned int) length_type->u.basic.integer.alignment, | |
526 | length_type->u.basic.integer.signedness, | |
527 | (length_type->u.basic.integer.encoding == lttng_encode_none) | |
528 | ? "none" | |
529 | : ((length_type->u.basic.integer.encoding == lttng_encode_UTF8) | |
530 | ? "UTF8" | |
531 | : "ASCII"), | |
532 | length_type->u.basic.integer.base, | |
533 | #ifdef __BIG_ENDIAN | |
534 | length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "", | |
535 | #else | |
536 | length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "", | |
537 | #endif | |
538 | field->name); | |
539 | if (ret) | |
540 | return ret; | |
541 | ||
542 | ret = lttng_metadata_printf(session, | |
543 | " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } %s[ __%s_length ];\n", | |
544 | elem_type->u.basic.integer.size, | |
545 | (unsigned int) elem_type->u.basic.integer.alignment, | |
546 | elem_type->u.basic.integer.signedness, | |
547 | (elem_type->u.basic.integer.encoding == lttng_encode_none) | |
548 | ? "none" | |
549 | : ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8) | |
550 | ? "UTF8" | |
551 | : "ASCII"), | |
552 | elem_type->u.basic.integer.base, | |
553 | #ifdef __BIG_ENDIAN | |
554 | elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "", | |
555 | #else | |
556 | elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "", | |
557 | #endif | |
558 | field->name, | |
559 | field->name); | |
560 | break; | |
561 | } | |
562 | ||
563 | case atype_string: | |
564 | /* Default encoding is UTF8 */ | |
565 | ret = lttng_metadata_printf(session, | |
566 | " string%s %s;\n", | |
567 | field->type.u.basic.string.encoding == lttng_encode_ASCII ? | |
568 | " { encoding = ASCII; }" : "", | |
569 | field->name); | |
570 | break; | |
571 | default: | |
572 | WARN_ON_ONCE(1); | |
573 | return -EINVAL; | |
574 | } | |
575 | return ret; | |
576 | } | |
577 | ||
578 | static | |
579 | int _ltt_context_metadata_statedump(struct ltt_session *session, | |
580 | struct lttng_ctx *ctx) | |
581 | { | |
582 | int ret = 0; | |
583 | int i; | |
584 | ||
585 | if (!ctx) | |
586 | return 0; | |
587 | for (i = 0; i < ctx->nr_fields; i++) { | |
588 | const struct lttng_ctx_field *field = &ctx->fields[i]; | |
589 | ||
590 | ret = _ltt_field_statedump(session, &field->event_field); | |
591 | if (ret) | |
592 | return ret; | |
593 | } | |
594 | return ret; | |
595 | } | |
596 | ||
597 | static | |
598 | int _ltt_fields_metadata_statedump(struct ltt_session *session, | |
599 | struct ltt_event *event) | |
600 | { | |
601 | const struct lttng_event_desc *desc = event->desc; | |
602 | int ret = 0; | |
603 | int i; | |
604 | ||
605 | for (i = 0; i < desc->nr_fields; i++) { | |
606 | const struct lttng_event_field *field = &desc->fields[i]; | |
607 | ||
608 | ret = _ltt_field_statedump(session, field); | |
609 | if (ret) | |
610 | return ret; | |
611 | } | |
612 | return ret; | |
613 | } | |
614 | ||
615 | static | |
616 | int _ltt_event_metadata_statedump(struct ltt_session *session, | |
617 | struct ltt_channel *chan, | |
618 | struct ltt_event *event) | |
619 | { | |
620 | int ret = 0; | |
621 | ||
622 | if (event->metadata_dumped || !ACCESS_ONCE(session->active)) | |
623 | return 0; | |
624 | if (chan == session->metadata) | |
625 | return 0; | |
626 | ||
627 | ret = lttng_metadata_printf(session, | |
628 | "event {\n" | |
629 | " name = %s;\n" | |
630 | " id = %u;\n" | |
631 | " stream_id = %u;\n", | |
632 | event->desc->name, | |
633 | event->id, | |
634 | event->chan->id); | |
635 | if (ret) | |
636 | goto end; | |
637 | ||
638 | if (event->ctx) { | |
639 | ret = lttng_metadata_printf(session, | |
640 | " context := struct {\n"); | |
641 | if (ret) | |
642 | goto end; | |
643 | } | |
644 | ret = _ltt_context_metadata_statedump(session, event->ctx); | |
645 | if (ret) | |
646 | goto end; | |
647 | if (event->ctx) { | |
648 | ret = lttng_metadata_printf(session, | |
649 | " };\n"); | |
650 | if (ret) | |
651 | goto end; | |
652 | } | |
653 | ||
654 | ret = lttng_metadata_printf(session, | |
655 | " fields := struct {\n" | |
656 | ); | |
657 | if (ret) | |
658 | goto end; | |
659 | ||
660 | ret = _ltt_fields_metadata_statedump(session, event); | |
661 | if (ret) | |
662 | goto end; | |
663 | ||
664 | /* | |
665 | * LTTng space reservation can only reserve multiples of the | |
666 | * byte size. | |
667 | */ | |
668 | ret = lttng_metadata_printf(session, | |
669 | " };\n" | |
670 | "};\n\n"); | |
671 | if (ret) | |
672 | goto end; | |
673 | ||
674 | event->metadata_dumped = 1; | |
675 | end: | |
676 | return ret; | |
677 | ||
678 | } | |
679 | ||
680 | static | |
681 | int _ltt_channel_metadata_statedump(struct ltt_session *session, | |
682 | struct ltt_channel *chan) | |
683 | { | |
684 | int ret = 0; | |
685 | ||
686 | if (chan->metadata_dumped || !ACCESS_ONCE(session->active)) | |
687 | return 0; | |
688 | if (chan == session->metadata) | |
689 | return 0; | |
690 | ||
691 | WARN_ON_ONCE(!chan->header_type); | |
692 | ret = lttng_metadata_printf(session, | |
693 | "stream {\n" | |
694 | " id = %u;\n" | |
695 | " event.header := %s;\n" | |
696 | " packet.context := struct packet_context;\n", | |
697 | chan->id, | |
698 | chan->header_type == 1 ? "struct event_header_compact" : | |
699 | "struct event_header_large"); | |
700 | if (ret) | |
701 | goto end; | |
702 | ||
703 | if (chan->ctx) { | |
704 | ret = lttng_metadata_printf(session, | |
705 | " event.context := struct {\n"); | |
706 | if (ret) | |
707 | goto end; | |
708 | } | |
709 | ret = _ltt_context_metadata_statedump(session, chan->ctx); | |
710 | if (ret) | |
711 | goto end; | |
712 | if (chan->ctx) { | |
713 | ret = lttng_metadata_printf(session, | |
714 | " };\n"); | |
715 | if (ret) | |
716 | goto end; | |
717 | } | |
718 | ||
719 | ret = lttng_metadata_printf(session, | |
720 | "};\n\n"); | |
721 | ||
722 | chan->metadata_dumped = 1; | |
723 | end: | |
724 | return ret; | |
725 | } | |
726 | ||
727 | static | |
728 | int _ltt_stream_packet_context_declare(struct ltt_session *session) | |
729 | { | |
730 | return lttng_metadata_printf(session, | |
731 | "struct packet_context {\n" | |
732 | " uint64_t timestamp_begin;\n" | |
733 | " uint64_t timestamp_end;\n" | |
734 | " uint32_t events_discarded;\n" | |
735 | " uint32_t content_size;\n" | |
736 | " uint32_t packet_size;\n" | |
737 | " uint32_t cpu_id;\n" | |
738 | "};\n\n" | |
739 | ); | |
740 | } | |
741 | ||
742 | /* | |
743 | * Compact header: | |
744 | * id: range: 0 - 30. | |
745 | * id 31 is reserved to indicate an extended header. | |
746 | * | |
747 | * Large header: | |
748 | * id: range: 0 - 65534. | |
749 | * id 65535 is reserved to indicate an extended header. | |
750 | */ | |
751 | static | |
752 | int _ltt_event_header_declare(struct ltt_session *session) | |
753 | { | |
754 | return lttng_metadata_printf(session, | |
755 | "struct event_header_compact {\n" | |
756 | " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n" | |
757 | " variant <id> {\n" | |
758 | " struct {\n" | |
759 | " uint27_t timestamp;\n" | |
760 | " } compact;\n" | |
761 | " struct {\n" | |
762 | " uint32_t id;\n" | |
763 | " uint64_t timestamp;\n" | |
764 | " } extended;\n" | |
765 | " } v;\n" | |
766 | "} align(%u);\n" | |
767 | "\n" | |
768 | "struct event_header_large {\n" | |
769 | " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n" | |
770 | " variant <id> {\n" | |
771 | " struct {\n" | |
772 | " uint32_t timestamp;\n" | |
773 | " } compact;\n" | |
774 | " struct {\n" | |
775 | " uint32_t id;\n" | |
776 | " uint64_t timestamp;\n" | |
777 | " } extended;\n" | |
778 | " } v;\n" | |
779 | "} align(%u);\n\n", | |
780 | ltt_alignof(uint32_t) * CHAR_BIT, | |
781 | ltt_alignof(uint16_t) * CHAR_BIT | |
782 | ); | |
783 | } | |
784 | ||
785 | /* | |
786 | * Output metadata into this session's metadata buffers. | |
787 | */ | |
788 | static | |
789 | int _ltt_session_metadata_statedump(struct ltt_session *session) | |
790 | { | |
791 | unsigned char *uuid_c = session->uuid.b; | |
792 | unsigned char uuid_s[37]; | |
793 | struct ltt_channel *chan; | |
794 | struct ltt_event *event; | |
795 | int ret = 0; | |
796 | ||
797 | if (!ACCESS_ONCE(session->active)) | |
798 | return 0; | |
799 | if (session->metadata_dumped) | |
800 | goto skip_session; | |
801 | if (!session->metadata) { | |
802 | printk(KERN_WARNING "LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n"); | |
803 | return -EPERM; | |
804 | } | |
805 | ||
806 | snprintf(uuid_s, sizeof(uuid_s), | |
807 | "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", | |
808 | uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3], | |
809 | uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7], | |
810 | uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11], | |
811 | uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]); | |
812 | ||
813 | ret = lttng_metadata_printf(session, | |
814 | "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n" | |
815 | "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n" | |
816 | "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n" | |
817 | "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n" | |
818 | "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n" | |
819 | "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n" | |
820 | "\n" | |
821 | "trace {\n" | |
822 | " major = %u;\n" | |
823 | " minor = %u;\n" | |
824 | " uuid = \"%s\";\n" | |
825 | " byte_order = %s;\n" | |
826 | " packet.header := struct {\n" | |
827 | " uint32_t magic;\n" | |
828 | " uint8_t uuid[16];\n" | |
829 | " uint32_t stream_id;\n" | |
830 | " };\n" | |
831 | "};\n\n", | |
832 | ltt_alignof(uint8_t) * CHAR_BIT, | |
833 | ltt_alignof(uint16_t) * CHAR_BIT, | |
834 | ltt_alignof(uint32_t) * CHAR_BIT, | |
835 | ltt_alignof(uint64_t) * CHAR_BIT, | |
836 | CTF_VERSION_MAJOR, | |
837 | CTF_VERSION_MINOR, | |
838 | uuid_s, | |
839 | #ifdef __BIG_ENDIAN | |
840 | "be" | |
841 | #else | |
842 | "le" | |
843 | #endif | |
844 | ); | |
845 | if (ret) | |
846 | goto end; | |
847 | ||
848 | ret = _ltt_stream_packet_context_declare(session); | |
849 | if (ret) | |
850 | goto end; | |
851 | ||
852 | ret = _ltt_event_header_declare(session); | |
853 | if (ret) | |
854 | goto end; | |
855 | ||
856 | skip_session: | |
857 | list_for_each_entry(chan, &session->chan, list) { | |
858 | ret = _ltt_channel_metadata_statedump(session, chan); | |
859 | if (ret) | |
860 | goto end; | |
861 | } | |
862 | ||
863 | list_for_each_entry(event, &session->events, list) { | |
864 | ret = _ltt_event_metadata_statedump(session, event->chan, event); | |
865 | if (ret) | |
866 | goto end; | |
867 | } | |
868 | session->metadata_dumped = 1; | |
869 | end: | |
870 | return ret; | |
871 | } | |
872 | ||
873 | /** | |
874 | * ltt_transport_register - LTT transport registration | |
875 | * @transport: transport structure | |
876 | * | |
877 | * Registers a transport which can be used as output to extract the data out of | |
878 | * LTTng. The module calling this registration function must ensure that no | |
879 | * trap-inducing code will be executed by the transport functions. E.g. | |
880 | * vmalloc_sync_all() must be called between a vmalloc and the moment the memory | |
881 | * is made visible to the transport function. This registration acts as a | |
882 | * vmalloc_sync_all. Therefore, only if the module allocates virtual memory | |
883 | * after its registration must it synchronize the TLBs. | |
884 | */ | |
885 | void ltt_transport_register(struct ltt_transport *transport) | |
886 | { | |
887 | /* | |
888 | * Make sure no page fault can be triggered by the module about to be | |
889 | * registered. We deal with this here so we don't have to call | |
890 | * vmalloc_sync_all() in each module's init. | |
891 | */ | |
892 | wrapper_vmalloc_sync_all(); | |
893 | ||
894 | mutex_lock(&sessions_mutex); | |
895 | list_add_tail(&transport->node, <t_transport_list); | |
896 | mutex_unlock(&sessions_mutex); | |
897 | } | |
898 | EXPORT_SYMBOL_GPL(ltt_transport_register); | |
899 | ||
900 | /** | |
901 | * ltt_transport_unregister - LTT transport unregistration | |
902 | * @transport: transport structure | |
903 | */ | |
904 | void ltt_transport_unregister(struct ltt_transport *transport) | |
905 | { | |
906 | mutex_lock(&sessions_mutex); | |
907 | list_del(&transport->node); | |
908 | mutex_unlock(&sessions_mutex); | |
909 | } | |
910 | EXPORT_SYMBOL_GPL(ltt_transport_unregister); | |
911 | ||
912 | static int __init ltt_events_init(void) | |
913 | { | |
914 | int ret; | |
915 | ||
916 | event_cache = KMEM_CACHE(ltt_event, 0); | |
917 | if (!event_cache) | |
918 | return -ENOMEM; | |
919 | ret = ltt_debugfs_abi_init(); | |
920 | if (ret) | |
921 | goto error_abi; | |
922 | return 0; | |
923 | error_abi: | |
924 | kmem_cache_destroy(event_cache); | |
925 | return ret; | |
926 | } | |
927 | ||
928 | module_init(ltt_events_init); | |
929 | ||
930 | static void __exit ltt_events_exit(void) | |
931 | { | |
932 | struct ltt_session *session, *tmpsession; | |
933 | ||
934 | ltt_debugfs_abi_exit(); | |
935 | list_for_each_entry_safe(session, tmpsession, &sessions, list) | |
936 | ltt_session_destroy(session); | |
937 | kmem_cache_destroy(event_cache); | |
938 | } | |
939 | ||
940 | module_exit(ltt_events_exit); | |
941 | ||
942 | MODULE_LICENSE("GPL and additional rights"); | |
943 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); | |
944 | MODULE_DESCRIPTION("LTTng Events"); |