Performance: define _LGPL_SOURCE in LGPL c files
[lttng-ust.git] / liblttng-ust / lttng-probes.c
CommitLineData
ce5aef0b 1/*
7dd08bec 2 * lttng-probes.c
ce5aef0b 3 *
ce5aef0b
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4 * Holds LTTng probes registry.
5 *
e92f3e28
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6 * Copyright 2010-2012 (c) - 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
ce5aef0b
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21 */
22
3fbec7dc 23#define _LGPL_SOURCE
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24#include <string.h>
25#include <errno.h>
26#include <urcu/list.h>
1f18504e 27#include <urcu/hlist.h>
4318ae1b 28#include <lttng/ust-events.h>
902e1379 29#include <lttng/tracepoint.h>
d8de1354 30#include "tracepoint-internal.h"
a3bb4b27 31#include <assert.h>
c8fcf224 32#include <helper.h>
48740cab 33#include <ctype.h>
ce5aef0b 34
7dd08bec 35#include "lttng-tracer-core.h"
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36#include "jhash.h"
37#include "error.h"
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38
39/*
17dfb34b 40 * probe list is protected by ust_lock()/ust_unlock().
8165c8da 41 */
ac69b35b 42static CDS_LIST_HEAD(_probe_list);
e58095ef 43
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44/*
45 * List of probes registered by not yet processed.
46 */
47static CDS_LIST_HEAD(lazy_probe_init);
df854e41 48
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49/*
50 * lazy_nesting counter ensures we don't trigger lazy probe registration
51 * fixup while we are performing the fixup. It is protected by the ust
52 * mutex.
53 */
54static int lazy_nesting;
df854e41 55
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56/*
57 * Called under ust lock.
58 */
ce5aef0b 59static
48205d60 60int check_event_provider(struct lttng_probe_desc *desc)
ce5aef0b 61{
ce5aef0b 62 int i;
48205d60 63 size_t provider_name_len;
ce5aef0b 64
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65 provider_name_len = strnlen(desc->provider,
66 LTTNG_UST_SYM_NAME_LEN - 1);
67 for (i = 0; i < desc->nr_events; i++) {
68 if (strncmp(desc->event_desc[i]->name,
69 desc->provider,
70 provider_name_len))
71 return 0; /* provider mismatch */
ce5aef0b 72 }
48205d60 73 return 1;
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74}
75
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76/*
77 * Called under ust lock.
78 */
79static
80void lttng_lazy_probe_register(struct lttng_probe_desc *desc)
ce5aef0b 81{
df854e41 82 struct lttng_probe_desc *iter;
ac69b35b 83 struct cds_list_head *probe_list;
48205d60 84
ce5aef0b 85 /*
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86 * Each provider enforce that every event name begins with the
87 * provider name. Check this in an assertion for extra
88 * carefulness. This ensures we cannot have duplicate event
89 * names across providers.
90 */
91 assert(check_event_provider(desc));
92
93 /*
94 * The provider ensures there are no duplicate event names.
95 * Duplicated TRACEPOINT_EVENT event names would generate a
96 * compile-time error due to duplicated symbol names.
ce5aef0b 97 */
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98
99 /*
100 * We sort the providers by struct lttng_probe_desc pointer
101 * address.
102 */
6715d7d1 103 probe_list = &_probe_list;
ac69b35b 104 cds_list_for_each_entry_reverse(iter, probe_list, head) {
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105 BUG_ON(iter == desc); /* Should never be in the list twice */
106 if (iter < desc) {
107 /* We belong to the location right after iter. */
108 cds_list_add(&desc->head, &iter->head);
109 goto desc_added;
110 }
111 }
112 /* We should be added at the head of the list */
ac69b35b 113 cds_list_add(&desc->head, probe_list);
df854e41 114desc_added:
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115 DBG("just registered probe %s containing %u events",
116 desc->provider, desc->nr_events);
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117}
118
119/*
120 * Called under ust lock.
121 */
122static
123void fixup_lazy_probes(void)
124{
125 struct lttng_probe_desc *iter, *tmp;
5f733922 126 int ret;
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127
128 lazy_nesting++;
129 cds_list_for_each_entry_safe(iter, tmp,
130 &lazy_probe_init, lazy_init_head) {
131 lttng_lazy_probe_register(iter);
132 iter->lazy = 0;
133 cds_list_del(&iter->lazy_init_head);
134 }
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135 ret = lttng_fix_pending_events();
136 assert(!ret);
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137 lazy_nesting--;
138}
139
140/*
141 * Called under ust lock.
142 */
143struct cds_list_head *lttng_get_probe_list_head(void)
144{
145 if (!lazy_nesting && !cds_list_empty(&lazy_probe_init))
146 fixup_lazy_probes();
147 return &_probe_list;
148}
149
150static
151const struct lttng_probe_desc *find_provider(const char *provider)
152{
153 struct lttng_probe_desc *iter;
154 struct cds_list_head *probe_list;
155
156 probe_list = lttng_get_probe_list_head();
157 cds_list_for_each_entry(iter, probe_list, head) {
158 if (!strcmp(iter->provider, provider))
159 return iter;
160 }
161 return NULL;
162}
163
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164static
165int check_provider_version(struct lttng_probe_desc *desc)
166{
167 /*
168 * Check tracepoint provider version compatibility.
169 */
170 if (desc->major <= LTTNG_UST_PROVIDER_MAJOR) {
171 DBG("Provider \"%s\" accepted, version %u.%u is compatible "
172 "with LTTng UST provider version %u.%u.",
173 desc->provider, desc->major, desc->minor,
174 LTTNG_UST_PROVIDER_MAJOR,
175 LTTNG_UST_PROVIDER_MINOR);
176 if (desc->major < LTTNG_UST_PROVIDER_MAJOR) {
177 DBG("However, some LTTng UST features might not be "
178 "available for this provider unless it is "
179 "recompiled against a more recent LTTng UST.");
180 }
181 return 1; /* accept */
182 } else {
183 ERR("Provider \"%s\" rejected, version %u.%u is incompatible "
184 "with LTTng UST provider version %u.%u. Please upgrade "
185 "LTTng UST.",
186 desc->provider, desc->major, desc->minor,
187 LTTNG_UST_PROVIDER_MAJOR,
188 LTTNG_UST_PROVIDER_MINOR);
189 return 0; /* reject */
190 }
191}
192
193
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194int lttng_probe_register(struct lttng_probe_desc *desc)
195{
196 int ret = 0;
197
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198 /*
199 * If version mismatch, don't register, but don't trigger assert
200 * on caller. The version check just prints an error.
201 */
202 if (!check_provider_version(desc))
203 return 0;
204
3327ac33 205 ust_lock_nocheck();
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206
207 /*
208 * Check if the provider has already been registered.
209 */
210 if (find_provider(desc->provider)) {
211 ret = -EEXIST;
212 goto end;
213 }
214 cds_list_add(&desc->lazy_init_head, &lazy_probe_init);
215 desc->lazy = 1;
216 DBG("adding probe %s containing %u events to lazy registration list",
217 desc->provider, desc->nr_events);
218 /*
219 * If there is at least one active session, we need to register
220 * the probe immediately, since we cannot delay event
221 * registration because they are needed ASAP.
222 */
223 if (lttng_session_active())
224 fixup_lazy_probes();
ce5aef0b 225end:
17dfb34b 226 ust_unlock();
ce5aef0b
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227 return ret;
228}
ce5aef0b 229
7dd08bec
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230/* Backward compatibility with UST 2.0 */
231int ltt_probe_register(struct lttng_probe_desc *desc)
232{
233 return lttng_probe_register(desc);
234}
235
236void lttng_probe_unregister(struct lttng_probe_desc *desc)
ce5aef0b 237{
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238 if (!check_provider_version(desc))
239 return;
240
3327ac33 241 ust_lock_nocheck();
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242 if (!desc->lazy)
243 cds_list_del(&desc->head);
244 else
245 cds_list_del(&desc->lazy_init_head);
e81a53af 246 DBG("just unregistered probe %s", desc->provider);
17dfb34b 247 ust_unlock();
ce5aef0b 248}
ce5aef0b 249
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250/* Backward compatibility with UST 2.0 */
251void ltt_probe_unregister(struct lttng_probe_desc *desc)
252{
253 lttng_probe_unregister(desc);
254}
255
7dd08bec 256void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
c8fcf224
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257{
258 struct tp_list_entry *list_entry, *tmp;
259
260 cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
261 cds_list_del(&list_entry->head);
262 free(list_entry);
263 }
264}
265
266/*
267 * called with UST lock held.
268 */
7dd08bec 269int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
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270{
271 struct lttng_probe_desc *probe_desc;
272 int i;
ac69b35b 273 struct cds_list_head *probe_list;
c8fcf224 274
ac69b35b 275 probe_list = lttng_get_probe_list_head();
c8fcf224 276 CDS_INIT_LIST_HEAD(&list->head);
ac69b35b 277 cds_list_for_each_entry(probe_desc, probe_list, head) {
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MD
278 for (i = 0; i < probe_desc->nr_events; i++) {
279 struct tp_list_entry *list_entry;
280
281 list_entry = zmalloc(sizeof(*list_entry));
282 if (!list_entry)
283 goto err_nomem;
284 cds_list_add(&list_entry->head, &list->head);
285 strncpy(list_entry->tp.name,
286 probe_desc->event_desc[i]->name,
287 LTTNG_UST_SYM_NAME_LEN);
288 list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
289 if (!probe_desc->event_desc[i]->loglevel) {
882a56d7 290 list_entry->tp.loglevel = TRACE_DEFAULT;
c8fcf224 291 } else {
882a56d7 292 list_entry->tp.loglevel = *(*probe_desc->event_desc[i]->loglevel);
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293 }
294 }
295 }
296 if (cds_list_empty(&list->head))
297 list->iter = NULL;
298 else
299 list->iter =
300 cds_list_first_entry(&list->head, struct tp_list_entry, head);
301 return 0;
302
303err_nomem:
7dd08bec 304 lttng_probes_prune_event_list(list);
c8fcf224
MD
305 return -ENOMEM;
306}
307
308/*
309 * Return current iteration position, advance internal iterator to next.
310 * Return NULL if end of list.
311 */
312struct lttng_ust_tracepoint_iter *
313 lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
314{
315 struct tp_list_entry *entry;
316
317 if (!list->iter)
318 return NULL;
319 entry = list->iter;
320 if (entry->head.next == &list->head)
321 list->iter = NULL;
322 else
323 list->iter = cds_list_entry(entry->head.next,
324 struct tp_list_entry, head);
325 return &entry->tp;
326}
1f18504e 327
7dd08bec 328void lttng_probes_prune_field_list(struct lttng_ust_field_list *list)
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329{
330 struct tp_field_list_entry *list_entry, *tmp;
331
332 cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
333 cds_list_del(&list_entry->head);
334 free(list_entry);
335 }
336}
337
338/*
339 * called with UST lock held.
340 */
7dd08bec 341int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
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342{
343 struct lttng_probe_desc *probe_desc;
344 int i;
ac69b35b 345 struct cds_list_head *probe_list;
06d4f27e 346
ac69b35b 347 probe_list = lttng_get_probe_list_head();
06d4f27e 348 CDS_INIT_LIST_HEAD(&list->head);
ac69b35b 349 cds_list_for_each_entry(probe_desc, probe_list, head) {
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350 for (i = 0; i < probe_desc->nr_events; i++) {
351 const struct lttng_event_desc *event_desc =
352 probe_desc->event_desc[i];
353 int j;
354
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MD
355 if (event_desc->nr_fields == 0) {
356 /* Events without fields. */
357 struct tp_field_list_entry *list_entry;
358
359 list_entry = zmalloc(sizeof(*list_entry));
360 if (!list_entry)
361 goto err_nomem;
362 cds_list_add(&list_entry->head, &list->head);
363 strncpy(list_entry->field.event_name,
364 event_desc->name,
365 LTTNG_UST_SYM_NAME_LEN);
366 list_entry->field.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
367 list_entry->field.field_name[0] = '\0';
368 list_entry->field.type = LTTNG_UST_FIELD_OTHER;
369 if (!event_desc->loglevel) {
370 list_entry->field.loglevel = TRACE_DEFAULT;
371 } else {
372 list_entry->field.loglevel = *(*event_desc->loglevel);
373 }
374 list_entry->field.nowrite = 1;
375 }
376
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377 for (j = 0; j < event_desc->nr_fields; j++) {
378 const struct lttng_event_field *event_field =
379 &event_desc->fields[j];
380 struct tp_field_list_entry *list_entry;
381
382 list_entry = zmalloc(sizeof(*list_entry));
383 if (!list_entry)
384 goto err_nomem;
385 cds_list_add(&list_entry->head, &list->head);
386 strncpy(list_entry->field.event_name,
387 event_desc->name,
388 LTTNG_UST_SYM_NAME_LEN);
389 list_entry->field.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
390 strncpy(list_entry->field.field_name,
391 event_field->name,
392 LTTNG_UST_SYM_NAME_LEN);
393 list_entry->field.field_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
40003310
MD
394 switch (event_field->type.atype) {
395 case atype_integer:
396 list_entry->field.type = LTTNG_UST_FIELD_INTEGER;
397 break;
398 case atype_string:
399 list_entry->field.type = LTTNG_UST_FIELD_STRING;
400 break;
401 case atype_array:
402 if (event_field->type.u.array.elem_type.atype != atype_integer
403 || event_field->type.u.array.elem_type.u.basic.integer.encoding == lttng_encode_none)
404 list_entry->field.type = LTTNG_UST_FIELD_OTHER;
405 else
406 list_entry->field.type = LTTNG_UST_FIELD_STRING;
407 break;
408 case atype_sequence:
409 if (event_field->type.u.sequence.elem_type.atype != atype_integer
410 || event_field->type.u.sequence.elem_type.u.basic.integer.encoding == lttng_encode_none)
411 list_entry->field.type = LTTNG_UST_FIELD_OTHER;
412 else
413 list_entry->field.type = LTTNG_UST_FIELD_STRING;
414 break;
415 case atype_float:
416 list_entry->field.type = LTTNG_UST_FIELD_FLOAT;
417 break;
418 case atype_enum:
419 list_entry->field.type = LTTNG_UST_FIELD_ENUM;
420 break;
421 default:
422 list_entry->field.type = LTTNG_UST_FIELD_OTHER;
423 }
06d4f27e
MD
424 if (!event_desc->loglevel) {
425 list_entry->field.loglevel = TRACE_DEFAULT;
426 } else {
427 list_entry->field.loglevel = *(*event_desc->loglevel);
428 }
180901e6 429 list_entry->field.nowrite = event_field->nowrite;
06d4f27e
MD
430 }
431 }
432 }
433 if (cds_list_empty(&list->head))
434 list->iter = NULL;
435 else
436 list->iter =
437 cds_list_first_entry(&list->head,
438 struct tp_field_list_entry, head);
439 return 0;
440
441err_nomem:
7dd08bec 442 lttng_probes_prune_field_list(list);
06d4f27e
MD
443 return -ENOMEM;
444}
445
446/*
447 * Return current iteration position, advance internal iterator to next.
448 * Return NULL if end of list.
449 */
450struct lttng_ust_field_iter *
451 lttng_ust_field_list_get_iter_next(struct lttng_ust_field_list *list)
452{
453 struct tp_field_list_entry *entry;
454
455 if (!list->iter)
456 return NULL;
457 entry = list->iter;
458 if (entry->head.next == &list->head)
459 list->iter = NULL;
460 else
461 list->iter = cds_list_entry(entry->head.next,
462 struct tp_field_list_entry, head);
463 return &entry->field;
464}
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