Commit | Line | Data |
---|---|---|
af0818ef JR |
1 | /* |
2 | * Copyright (C) 2019 Jonathan Rajotte <jonathan.rajotte-julien@efficios.com> | |
3 | * | |
4 | * SPDX-License-Identifier: LGPL-2.1-only | |
5 | * | |
6 | */ | |
7 | ||
8 | #include <assert.h> | |
9 | #include <common/credentials.h> | |
10 | #include <common/error.h> | |
6a751b95 JR |
11 | #include <common/hashtable/hashtable.h> |
12 | #include <common/hashtable/utils.h> | |
af0818ef | 13 | #include <common/macros.h> |
6a751b95 | 14 | #include <common/mi-lttng.h> |
af0818ef | 15 | #include <common/optional.h> |
af0818ef | 16 | #include <common/payload-view.h> |
6a751b95 | 17 | #include <common/payload.h> |
af0818ef | 18 | #include <common/runas.h> |
af0818ef JR |
19 | #include <common/string-utils/string-utils.h> |
20 | #include <lttng/event-rule/event-rule-internal.h> | |
21 | #include <lttng/event-rule/kernel-tracepoint-internal.h> | |
22 | #include <lttng/event.h> | |
23 | ||
24 | #define IS_KERNEL_TRACEPOINT_EVENT_RULE(rule) \ | |
25 | (lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_KERNEL_TRACEPOINT) | |
26 | ||
27 | static void lttng_event_rule_kernel_tracepoint_destroy(struct lttng_event_rule *rule) | |
28 | { | |
29 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
30 | ||
31 | if (rule == NULL) { | |
32 | return; | |
33 | } | |
34 | ||
35 | tracepoint = container_of( | |
36 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
37 | ||
38 | free(tracepoint->pattern); | |
39 | free(tracepoint->filter_expression); | |
40 | free(tracepoint->internal_filter.filter); | |
41 | free(tracepoint->internal_filter.bytecode); | |
42 | free(tracepoint); | |
43 | } | |
44 | ||
45 | static bool lttng_event_rule_kernel_tracepoint_validate( | |
46 | const struct lttng_event_rule *rule) | |
47 | { | |
48 | bool valid = false; | |
49 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
50 | ||
51 | if (!rule) { | |
52 | goto end; | |
53 | } | |
54 | ||
55 | tracepoint = container_of( | |
56 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
57 | ||
58 | /* Required field. */ | |
59 | if (!tracepoint->pattern) { | |
60 | ERR("Invalid kernel tracepoint event rule: a pattern must be set."); | |
61 | goto end; | |
62 | } | |
63 | ||
64 | valid = true; | |
65 | end: | |
66 | return valid; | |
67 | } | |
68 | ||
69 | static int lttng_event_rule_kernel_tracepoint_serialize( | |
70 | const struct lttng_event_rule *rule, | |
71 | struct lttng_payload *payload) | |
72 | { | |
73 | int ret; | |
74 | size_t pattern_len, filter_expression_len; | |
75 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
76 | struct lttng_event_rule_kernel_tracepoint_comm tracepoint_comm; | |
77 | ||
78 | if (!rule || !IS_KERNEL_TRACEPOINT_EVENT_RULE(rule)) { | |
79 | ret = -1; | |
80 | goto end; | |
81 | } | |
82 | ||
83 | DBG("Serializing kernel tracepoint event rule."); | |
84 | tracepoint = container_of( | |
85 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
86 | ||
87 | pattern_len = strlen(tracepoint->pattern) + 1; | |
88 | ||
89 | if (tracepoint->filter_expression != NULL) { | |
90 | filter_expression_len = | |
91 | strlen(tracepoint->filter_expression) + 1; | |
92 | } else { | |
93 | filter_expression_len = 0; | |
94 | } | |
95 | ||
96 | tracepoint_comm.pattern_len = pattern_len; | |
97 | tracepoint_comm.filter_expression_len = filter_expression_len; | |
98 | ||
99 | ret = lttng_dynamic_buffer_append(&payload->buffer, &tracepoint_comm, | |
100 | sizeof(tracepoint_comm)); | |
101 | if (ret) { | |
102 | goto end; | |
103 | } | |
104 | ||
105 | ret = lttng_dynamic_buffer_append( | |
106 | &payload->buffer, tracepoint->pattern, pattern_len); | |
107 | if (ret) { | |
108 | goto end; | |
109 | } | |
110 | ||
111 | ret = lttng_dynamic_buffer_append(&payload->buffer, tracepoint->filter_expression, | |
112 | filter_expression_len); | |
113 | if (ret) { | |
114 | goto end; | |
115 | } | |
116 | ||
117 | end: | |
118 | return ret; | |
119 | } | |
120 | ||
121 | static bool lttng_event_rule_kernel_tracepoint_is_equal( | |
122 | const struct lttng_event_rule *_a, | |
123 | const struct lttng_event_rule *_b) | |
124 | { | |
125 | bool is_equal = false; | |
126 | struct lttng_event_rule_kernel_tracepoint *a, *b; | |
127 | ||
128 | a = container_of(_a, struct lttng_event_rule_kernel_tracepoint, parent); | |
129 | b = container_of(_b, struct lttng_event_rule_kernel_tracepoint, parent); | |
130 | ||
131 | if (!!a->filter_expression != !!b->filter_expression) { | |
132 | goto end; | |
133 | } | |
134 | ||
135 | /* Long check. */ | |
136 | assert(a->pattern); | |
137 | assert(b->pattern); | |
138 | if (strcmp(a->pattern, b->pattern)) { | |
139 | goto end; | |
140 | } | |
141 | ||
142 | if (a->filter_expression && b->filter_expression) { | |
143 | if (strcmp(a->filter_expression, b->filter_expression)) { | |
144 | goto end; | |
145 | } | |
146 | } else if (!!a->filter_expression != !!b->filter_expression) { | |
147 | /* One is set; not the other. */ | |
148 | goto end; | |
149 | } | |
150 | ||
151 | is_equal = true; | |
152 | end: | |
153 | return is_equal; | |
154 | } | |
155 | ||
156 | static enum lttng_error_code | |
157 | lttng_event_rule_kernel_tracepoint_generate_filter_bytecode( | |
158 | struct lttng_event_rule *rule, | |
159 | const struct lttng_credentials *creds) | |
160 | { | |
161 | int ret; | |
162 | enum lttng_error_code ret_code; | |
163 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
164 | enum lttng_event_rule_status status; | |
165 | const char *filter; | |
166 | struct lttng_bytecode *bytecode = NULL; | |
167 | ||
168 | assert(rule); | |
169 | ||
170 | tracepoint = container_of( | |
171 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
172 | ||
173 | status = lttng_event_rule_kernel_tracepoint_get_filter(rule, &filter); | |
174 | if (status == LTTNG_EVENT_RULE_STATUS_UNSET) { | |
175 | filter = NULL; | |
176 | } else if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
177 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
178 | goto end; | |
179 | } | |
180 | ||
181 | if (filter && filter[0] == '\0') { | |
182 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
183 | goto error; | |
184 | } | |
185 | ||
186 | if (filter) { | |
187 | tracepoint->internal_filter.filter = strdup(filter); | |
188 | if (tracepoint->internal_filter.filter == NULL) { | |
189 | ret_code = LTTNG_ERR_NOMEM; | |
190 | goto error; | |
191 | } | |
192 | } else { | |
193 | tracepoint->internal_filter.filter = NULL; | |
194 | } | |
195 | ||
196 | if (tracepoint->internal_filter.filter == NULL) { | |
197 | ret_code = LTTNG_OK; | |
198 | goto end; | |
199 | } | |
200 | ||
201 | ret = run_as_generate_filter_bytecode( | |
202 | tracepoint->internal_filter.filter, creds, | |
203 | &bytecode); | |
204 | if (ret) { | |
205 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
206 | goto end; | |
207 | } | |
208 | ||
209 | tracepoint->internal_filter.bytecode = bytecode; | |
210 | bytecode = NULL; | |
211 | ret_code = LTTNG_OK; | |
212 | ||
213 | error: | |
214 | end: | |
215 | free(bytecode); | |
216 | return ret_code; | |
217 | } | |
218 | ||
219 | static const char *lttng_event_rule_kernel_tracepoint_get_internal_filter( | |
220 | const struct lttng_event_rule *rule) | |
221 | { | |
222 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
223 | ||
224 | assert(rule); | |
225 | tracepoint = container_of( | |
226 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
227 | return tracepoint->internal_filter.filter; | |
228 | } | |
229 | ||
230 | static const struct lttng_bytecode * | |
231 | lttng_event_rule_kernel_tracepoint_get_internal_filter_bytecode( | |
232 | const struct lttng_event_rule *rule) | |
233 | { | |
234 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
235 | ||
236 | assert(rule); | |
237 | tracepoint = container_of( | |
238 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
239 | return tracepoint->internal_filter.bytecode; | |
240 | } | |
241 | ||
242 | static enum lttng_event_rule_generate_exclusions_status | |
243 | lttng_event_rule_kernel_tracepoint_generate_exclusions( | |
244 | const struct lttng_event_rule *rule, | |
245 | struct lttng_event_exclusion **_exclusions) | |
246 | { | |
247 | /* Unsupported. */ | |
248 | *_exclusions = NULL; | |
249 | return LTTNG_EVENT_RULE_GENERATE_EXCLUSIONS_STATUS_NONE; | |
250 | } | |
251 | ||
252 | static unsigned long lttng_event_rule_kernel_tracepoint_hash( | |
253 | const struct lttng_event_rule *rule) | |
254 | { | |
255 | unsigned long hash; | |
256 | struct lttng_event_rule_kernel_tracepoint *tp_rule = | |
257 | container_of(rule, typeof(*tp_rule), parent); | |
258 | ||
259 | hash = hash_key_ulong((void *) LTTNG_EVENT_RULE_TYPE_KERNEL_TRACEPOINT, | |
260 | lttng_ht_seed); | |
261 | hash ^= hash_key_str(tp_rule->pattern, lttng_ht_seed); | |
262 | ||
263 | if (tp_rule->filter_expression) { | |
264 | hash ^= hash_key_str(tp_rule->filter_expression, lttng_ht_seed); | |
265 | } | |
266 | ||
267 | return hash; | |
268 | } | |
269 | ||
6a751b95 JR |
270 | static enum lttng_error_code lttng_event_rule_kernel_tracepoint_mi_serialize( |
271 | const struct lttng_event_rule *rule, struct mi_writer *writer) | |
272 | { | |
273 | int ret; | |
274 | enum lttng_error_code ret_code; | |
275 | enum lttng_event_rule_status status; | |
276 | const char *filter = NULL; | |
277 | const char *name_pattern = NULL; | |
278 | ||
279 | assert(rule); | |
280 | assert(writer); | |
281 | assert(IS_KERNEL_TRACEPOINT_EVENT_RULE(rule)); | |
282 | ||
283 | status = lttng_event_rule_kernel_tracepoint_get_name_pattern( | |
284 | rule, &name_pattern); | |
285 | assert(status == LTTNG_EVENT_RULE_STATUS_OK); | |
286 | assert(name_pattern); | |
287 | ||
288 | status = lttng_event_rule_kernel_tracepoint_get_filter(rule, &filter); | |
289 | assert(status == LTTNG_EVENT_RULE_STATUS_OK || | |
290 | status == LTTNG_EVENT_RULE_STATUS_UNSET); | |
291 | ||
292 | /* Open event rule kernel tracepoint element. */ | |
293 | ret = mi_lttng_writer_open_element( | |
294 | writer, mi_lttng_element_event_rule_kernel_tracepoint); | |
295 | if (ret) { | |
296 | goto mi_error; | |
297 | } | |
298 | ||
299 | /* Name pattern. */ | |
300 | ret = mi_lttng_writer_write_element_string(writer, | |
301 | mi_lttng_element_event_rule_name_pattern, name_pattern); | |
302 | if (ret) { | |
303 | goto mi_error; | |
304 | } | |
305 | ||
306 | /* Filter. */ | |
307 | if (filter != NULL) { | |
308 | ret = mi_lttng_writer_write_element_string(writer, | |
309 | mi_lttng_element_event_rule_filter_expression, | |
310 | filter); | |
311 | if (ret) { | |
312 | goto mi_error; | |
313 | } | |
314 | } | |
315 | ||
316 | /* Close event rule kernel tracepoint element. */ | |
317 | ret = mi_lttng_writer_close_element(writer); | |
318 | if (ret) { | |
319 | goto mi_error; | |
320 | } | |
321 | ||
322 | ret_code = LTTNG_OK; | |
323 | goto end; | |
324 | ||
325 | mi_error: | |
326 | ret_code = LTTNG_ERR_MI_IO_FAIL; | |
327 | end: | |
328 | return ret_code; | |
329 | } | |
330 | ||
af0818ef JR |
331 | struct lttng_event_rule *lttng_event_rule_kernel_tracepoint_create(void) |
332 | { | |
333 | struct lttng_event_rule *rule = NULL; | |
334 | struct lttng_event_rule_kernel_tracepoint *tp_rule; | |
335 | enum lttng_event_rule_status status; | |
336 | ||
337 | tp_rule = zmalloc(sizeof(struct lttng_event_rule_kernel_tracepoint)); | |
338 | if (!tp_rule) { | |
339 | goto end; | |
340 | } | |
341 | ||
342 | rule = &tp_rule->parent; | |
343 | lttng_event_rule_init(&tp_rule->parent, LTTNG_EVENT_RULE_TYPE_KERNEL_TRACEPOINT); | |
344 | tp_rule->parent.validate = lttng_event_rule_kernel_tracepoint_validate; | |
345 | tp_rule->parent.serialize = lttng_event_rule_kernel_tracepoint_serialize; | |
346 | tp_rule->parent.equal = lttng_event_rule_kernel_tracepoint_is_equal; | |
347 | tp_rule->parent.destroy = lttng_event_rule_kernel_tracepoint_destroy; | |
348 | tp_rule->parent.generate_filter_bytecode = | |
349 | lttng_event_rule_kernel_tracepoint_generate_filter_bytecode; | |
350 | tp_rule->parent.get_filter = | |
351 | lttng_event_rule_kernel_tracepoint_get_internal_filter; | |
352 | tp_rule->parent.get_filter_bytecode = | |
353 | lttng_event_rule_kernel_tracepoint_get_internal_filter_bytecode; | |
354 | tp_rule->parent.generate_exclusions = | |
355 | lttng_event_rule_kernel_tracepoint_generate_exclusions; | |
356 | tp_rule->parent.hash = lttng_event_rule_kernel_tracepoint_hash; | |
6a751b95 | 357 | tp_rule->parent.mi_serialize = lttng_event_rule_kernel_tracepoint_mi_serialize; |
af0818ef JR |
358 | |
359 | /* Not necessary for now. */ | |
360 | tp_rule->parent.generate_lttng_event = NULL; | |
361 | ||
362 | /* Default pattern is '*'. */ | |
363 | status = lttng_event_rule_kernel_tracepoint_set_name_pattern(rule, "*"); | |
364 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
365 | lttng_event_rule_destroy(rule); | |
366 | rule = NULL; | |
367 | } | |
368 | ||
369 | end: | |
370 | return rule; | |
371 | } | |
372 | ||
373 | LTTNG_HIDDEN | |
374 | ssize_t lttng_event_rule_kernel_tracepoint_create_from_payload( | |
375 | struct lttng_payload_view *view, | |
376 | struct lttng_event_rule **_event_rule) | |
377 | { | |
378 | ssize_t ret, offset = 0; | |
379 | enum lttng_event_rule_status status; | |
380 | const struct lttng_event_rule_kernel_tracepoint_comm *tracepoint_comm; | |
381 | const char *pattern; | |
382 | const char *filter_expression = NULL; | |
383 | struct lttng_buffer_view current_buffer_view; | |
384 | struct lttng_event_rule *rule = NULL; | |
385 | ||
386 | if (!_event_rule) { | |
387 | ret = -1; | |
388 | goto end; | |
389 | } | |
390 | ||
391 | current_buffer_view = lttng_buffer_view_from_view( | |
392 | &view->buffer, offset, sizeof(*tracepoint_comm)); | |
393 | if (!lttng_buffer_view_is_valid(¤t_buffer_view)) { | |
394 | ERR("Failed to initialize from malformed event rule kernel tracepoint: buffer too short to contain header."); | |
395 | ret = -1; | |
396 | goto end; | |
397 | } | |
398 | ||
399 | tracepoint_comm = (typeof(tracepoint_comm)) current_buffer_view.data; | |
400 | ||
401 | /* Skip to payload. */ | |
402 | offset += current_buffer_view.size; | |
403 | ||
404 | /* Map the pattern. */ | |
405 | current_buffer_view = lttng_buffer_view_from_view( | |
406 | &view->buffer, offset, tracepoint_comm->pattern_len); | |
407 | ||
408 | if (!lttng_buffer_view_is_valid(¤t_buffer_view)) { | |
409 | ret = -1; | |
410 | goto end; | |
411 | } | |
412 | ||
413 | pattern = current_buffer_view.data; | |
414 | if (!lttng_buffer_view_contains_string(¤t_buffer_view, pattern, | |
415 | tracepoint_comm->pattern_len)) { | |
416 | ret = -1; | |
417 | goto end; | |
418 | } | |
419 | ||
420 | /* Skip after the pattern. */ | |
421 | offset += tracepoint_comm->pattern_len; | |
422 | ||
423 | if (!tracepoint_comm->filter_expression_len) { | |
424 | goto skip_filter_expression; | |
425 | } | |
426 | ||
427 | /* Map the filter_expression. */ | |
428 | current_buffer_view = lttng_buffer_view_from_view(&view->buffer, offset, | |
429 | tracepoint_comm->filter_expression_len); | |
430 | if (!lttng_buffer_view_is_valid(¤t_buffer_view)) { | |
431 | ret = -1; | |
432 | goto end; | |
433 | } | |
434 | ||
435 | filter_expression = current_buffer_view.data; | |
436 | if (!lttng_buffer_view_contains_string(¤t_buffer_view, | |
437 | filter_expression, | |
438 | tracepoint_comm->filter_expression_len)) { | |
439 | ret = -1; | |
440 | goto end; | |
441 | } | |
442 | ||
443 | /* Skip after the pattern. */ | |
444 | offset += tracepoint_comm->filter_expression_len; | |
445 | ||
446 | skip_filter_expression: | |
447 | ||
448 | rule = lttng_event_rule_kernel_tracepoint_create(); | |
449 | if (!rule) { | |
450 | ERR("Failed to create event rule kernel tracepoint."); | |
451 | ret = -1; | |
452 | goto end; | |
453 | } | |
454 | ||
455 | status = lttng_event_rule_kernel_tracepoint_set_name_pattern(rule, pattern); | |
456 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
457 | ERR("Failed to set event rule kernel tracepoint pattern."); | |
458 | ret = -1; | |
459 | goto end; | |
460 | } | |
461 | ||
462 | if (filter_expression) { | |
463 | status = lttng_event_rule_kernel_tracepoint_set_filter( | |
464 | rule, filter_expression); | |
465 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
466 | ERR("Failed to set event rule kernel tracepoint pattern."); | |
467 | ret = -1; | |
468 | goto end; | |
469 | } | |
470 | } | |
471 | ||
472 | *_event_rule = rule; | |
473 | rule = NULL; | |
474 | ret = offset; | |
475 | end: | |
476 | lttng_event_rule_destroy(rule); | |
477 | return ret; | |
478 | } | |
479 | ||
480 | enum lttng_event_rule_status lttng_event_rule_kernel_tracepoint_set_name_pattern( | |
481 | struct lttng_event_rule *rule, const char *pattern) | |
482 | { | |
483 | char *pattern_copy = NULL; | |
484 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
485 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
486 | ||
487 | if (!rule || !IS_KERNEL_TRACEPOINT_EVENT_RULE(rule) || !pattern || | |
488 | strlen(pattern) == 0) { | |
489 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
490 | goto end; | |
491 | } | |
492 | ||
493 | tracepoint = container_of( | |
494 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
495 | pattern_copy = strdup(pattern); | |
496 | if (!pattern_copy) { | |
497 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
498 | goto end; | |
499 | } | |
500 | ||
501 | /* Normalize the pattern. */ | |
502 | strutils_normalize_star_glob_pattern(pattern_copy); | |
503 | ||
504 | free(tracepoint->pattern); | |
505 | ||
506 | tracepoint->pattern = pattern_copy; | |
507 | pattern_copy = NULL; | |
508 | end: | |
509 | return status; | |
510 | } | |
511 | ||
512 | enum lttng_event_rule_status lttng_event_rule_kernel_tracepoint_get_name_pattern( | |
513 | const struct lttng_event_rule *rule, const char **pattern) | |
514 | { | |
515 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
516 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
517 | ||
518 | if (!rule || !IS_KERNEL_TRACEPOINT_EVENT_RULE(rule) || !pattern) { | |
519 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
520 | goto end; | |
521 | } | |
522 | ||
523 | tracepoint = container_of( | |
524 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
525 | if (!tracepoint->pattern) { | |
526 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
527 | goto end; | |
528 | } | |
529 | ||
530 | *pattern = tracepoint->pattern; | |
531 | end: | |
532 | return status; | |
533 | } | |
534 | ||
535 | enum lttng_event_rule_status lttng_event_rule_kernel_tracepoint_set_filter( | |
536 | struct lttng_event_rule *rule, const char *expression) | |
537 | { | |
538 | char *expression_copy = NULL; | |
539 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
540 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
541 | ||
542 | if (!rule || !IS_KERNEL_TRACEPOINT_EVENT_RULE(rule) || !expression || | |
543 | strlen(expression) == 0) { | |
544 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
545 | goto end; | |
546 | } | |
547 | ||
548 | tracepoint = container_of( | |
549 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
550 | expression_copy = strdup(expression); | |
551 | if (!expression_copy) { | |
552 | PERROR("Failed to copy filter expression"); | |
553 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
554 | goto end; | |
555 | } | |
556 | ||
557 | if (tracepoint->filter_expression) { | |
558 | free(tracepoint->filter_expression); | |
559 | } | |
560 | ||
561 | tracepoint->filter_expression = expression_copy; | |
562 | expression_copy = NULL; | |
563 | end: | |
564 | return status; | |
565 | } | |
566 | ||
567 | enum lttng_event_rule_status lttng_event_rule_kernel_tracepoint_get_filter( | |
568 | const struct lttng_event_rule *rule, const char **expression) | |
569 | { | |
570 | struct lttng_event_rule_kernel_tracepoint *tracepoint; | |
571 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
572 | ||
573 | if (!rule || !IS_KERNEL_TRACEPOINT_EVENT_RULE(rule) || !expression) { | |
574 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
575 | goto end; | |
576 | } | |
577 | ||
578 | tracepoint = container_of( | |
579 | rule, struct lttng_event_rule_kernel_tracepoint, parent); | |
580 | if (!tracepoint->filter_expression) { | |
581 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
582 | goto end; | |
583 | } | |
584 | ||
585 | *expression = tracepoint->filter_expression; | |
586 | end: | |
587 | return status; | |
588 | } |