Add base support for event rule hit
[lttng-tools.git] / src / common / event-rule / syscall.c
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>
11 #include <common/macros.h>
12 #include <common/payload.h>
13 #include <common/payload-view.h>
14 #include <common/runas.h>
15 #include <common/hashtable/hashtable.h>
16 #include <common/hashtable/utils.h>
17 #include <lttng/event-rule/event-rule-internal.h>
18 #include <lttng/event-rule/syscall-internal.h>
19
20 #define IS_SYSCALL_EVENT_RULE(rule) \
21 (lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_SYSCALL)
22
23 static void lttng_event_rule_syscall_destroy(struct lttng_event_rule *rule)
24 {
25 struct lttng_event_rule_syscall *syscall;
26
27 if (rule == NULL) {
28 return;
29 }
30
31 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
32
33 free(syscall->pattern);
34 free(syscall->filter_expression);
35 free(syscall->internal_filter.filter);
36 free(syscall->internal_filter.bytecode);
37 free(syscall);
38 }
39
40 static bool lttng_event_rule_syscall_validate(
41 const struct lttng_event_rule *rule)
42 {
43 bool valid = false;
44 struct lttng_event_rule_syscall *syscall;
45
46 if (!rule) {
47 goto end;
48 }
49
50 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
51
52 /* Required field. */
53 if (!syscall->pattern) {
54 ERR("Invalid syscall event rule: a pattern must be set.");
55 goto end;
56 }
57
58 valid = true;
59 end:
60 return valid;
61 }
62
63 static int lttng_event_rule_syscall_serialize(
64 const struct lttng_event_rule *rule,
65 struct lttng_payload *payload)
66 {
67 int ret;
68 size_t pattern_len, filter_expression_len;
69 struct lttng_event_rule_syscall *syscall;
70 struct lttng_event_rule_syscall_comm syscall_comm;
71
72 if (!rule || !IS_SYSCALL_EVENT_RULE(rule)) {
73 ret = -1;
74 goto end;
75 }
76
77 DBG("Serializing syscall event rule");
78 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
79
80 pattern_len = strlen(syscall->pattern) + 1;
81
82 if (syscall->filter_expression != NULL) {
83 filter_expression_len = strlen(syscall->filter_expression) + 1;
84 } else {
85 filter_expression_len = 0;
86 }
87
88 syscall_comm.pattern_len = pattern_len;
89 syscall_comm.filter_expression_len = filter_expression_len;
90
91 ret = lttng_dynamic_buffer_append(
92 &payload->buffer, &syscall_comm, sizeof(syscall_comm));
93 if (ret) {
94 goto end;
95 }
96
97 ret = lttng_dynamic_buffer_append(
98 &payload->buffer, syscall->pattern, pattern_len);
99 if (ret) {
100 goto end;
101 }
102
103 ret = lttng_dynamic_buffer_append(&payload->buffer,
104 syscall->filter_expression, filter_expression_len);
105 end:
106 return ret;
107 }
108
109 static bool lttng_event_rule_syscall_is_equal(const struct lttng_event_rule *_a,
110 const struct lttng_event_rule *_b)
111 {
112 bool is_equal = false;
113 struct lttng_event_rule_syscall *a, *b;
114
115 a = container_of(_a, struct lttng_event_rule_syscall, parent);
116 b = container_of(_b, struct lttng_event_rule_syscall, parent);
117
118 if (!!a->filter_expression != !!b->filter_expression) {
119 goto end;
120 }
121
122 assert(a->pattern);
123 assert(b->pattern);
124 if (strcmp(a->pattern, b->pattern)) {
125 goto end;
126 }
127
128 if (a->filter_expression && b->filter_expression) {
129 if (strcmp(a->filter_expression, b->filter_expression)) {
130 goto end;
131 }
132 } else if (!!a->filter_expression != !!b->filter_expression) {
133 /* One is set and not the other. */
134 goto end;
135 }
136
137 is_equal = true;
138 end:
139 return is_equal;
140 }
141
142 static enum lttng_error_code lttng_event_rule_syscall_generate_filter_bytecode(
143 struct lttng_event_rule *rule,
144 const struct lttng_credentials *creds)
145 {
146 int ret;
147 enum lttng_error_code ret_code = LTTNG_OK;
148 struct lttng_event_rule_syscall *syscall;
149 enum lttng_event_rule_status status;
150 const char *filter;
151 struct lttng_filter_bytecode *bytecode = NULL;
152
153 assert(rule);
154
155 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
156
157 /* Generate the filter bytecode. */
158 status = lttng_event_rule_syscall_get_filter(rule, &filter);
159 if (status == LTTNG_EVENT_RULE_STATUS_UNSET) {
160 filter = NULL;
161 } else if (status != LTTNG_EVENT_RULE_STATUS_OK) {
162 ret_code = LTTNG_ERR_FILTER_INVAL;
163 goto end;
164 }
165
166 if (filter && filter[0] == '\0') {
167 ret_code = LTTNG_ERR_FILTER_INVAL;
168 goto end;
169 }
170
171 if (filter == NULL) {
172 /* Nothing to do. */
173 ret = LTTNG_OK;
174 goto end;
175 }
176
177 syscall->internal_filter.filter = strdup(filter);
178 if (syscall->internal_filter.filter == NULL) {
179 ret_code = LTTNG_ERR_NOMEM;
180 goto end;
181 }
182
183 ret = run_as_generate_filter_bytecode(
184 syscall->internal_filter.filter, creds, &bytecode);
185 if (ret) {
186 ret_code = LTTNG_ERR_FILTER_INVAL;
187 }
188
189 syscall->internal_filter.bytecode = bytecode;
190 bytecode = NULL;
191
192 end:
193 free(bytecode);
194 return ret_code;
195 }
196
197 static const char *lttng_event_rule_syscall_get_internal_filter(
198 const struct lttng_event_rule *rule)
199 {
200 struct lttng_event_rule_syscall *syscall;
201
202 assert(rule);
203 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
204
205 return syscall->internal_filter.filter;
206 }
207
208 static const struct lttng_filter_bytecode *
209 lttng_event_rule_syscall_get_internal_filter_bytecode(
210 const struct lttng_event_rule *rule)
211 {
212 struct lttng_event_rule_syscall *syscall;
213
214 assert(rule);
215 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
216
217 return syscall->internal_filter.bytecode;
218 }
219
220 static struct lttng_event_exclusion *
221 lttng_event_rule_syscall_generate_exclusions(
222 const struct lttng_event_rule *rule)
223 {
224 /* Not supported. */
225 return NULL;
226 }
227
228 static unsigned long
229 lttng_event_rule_syscall_hash(
230 const struct lttng_event_rule *rule)
231 {
232 unsigned long hash;
233 struct lttng_event_rule_syscall *syscall_rule =
234 container_of(rule, typeof(*syscall_rule), parent);
235
236 hash = hash_key_ulong((void *) LTTNG_EVENT_RULE_TYPE_SYSCALL,
237 lttng_ht_seed);
238 hash ^= hash_key_str(syscall_rule->pattern, lttng_ht_seed);
239 if (syscall_rule->filter_expression) {
240 hash ^= hash_key_str(syscall_rule->filter_expression,
241 lttng_ht_seed);
242 }
243
244 return hash;
245 }
246
247 struct lttng_event_rule *lttng_event_rule_syscall_create()
248 {
249 struct lttng_event_rule *rule = NULL;
250 struct lttng_event_rule_syscall *syscall_rule;
251
252 syscall_rule = zmalloc(sizeof(struct lttng_event_rule_syscall));
253 if (!syscall_rule) {
254 goto end;
255 }
256
257 rule = &syscall_rule->parent;
258 lttng_event_rule_init(
259 &syscall_rule->parent, LTTNG_EVENT_RULE_TYPE_SYSCALL);
260 syscall_rule->parent.validate = lttng_event_rule_syscall_validate;
261 syscall_rule->parent.serialize = lttng_event_rule_syscall_serialize;
262 syscall_rule->parent.equal = lttng_event_rule_syscall_is_equal;
263 syscall_rule->parent.destroy = lttng_event_rule_syscall_destroy;
264 syscall_rule->parent.generate_filter_bytecode =
265 lttng_event_rule_syscall_generate_filter_bytecode;
266 syscall_rule->parent.get_filter =
267 lttng_event_rule_syscall_get_internal_filter;
268 syscall_rule->parent.get_filter_bytecode =
269 lttng_event_rule_syscall_get_internal_filter_bytecode;
270 syscall_rule->parent.generate_exclusions =
271 lttng_event_rule_syscall_generate_exclusions;
272 syscall_rule->parent.hash = lttng_event_rule_syscall_hash;
273 end:
274 return rule;
275 }
276
277 LTTNG_HIDDEN
278 ssize_t lttng_event_rule_syscall_create_from_payload(
279 struct lttng_payload_view *view,
280 struct lttng_event_rule **_event_rule)
281 {
282 ssize_t ret, offset = 0;
283 enum lttng_event_rule_status status;
284 const struct lttng_event_rule_syscall_comm *syscall_comm;
285 const char *pattern;
286 const char *filter_expression = NULL;
287 struct lttng_buffer_view current_buffer_view;
288 struct lttng_event_rule *rule = NULL;
289
290 if (!_event_rule) {
291 ret = -1;
292 goto end;
293 }
294
295 if (view->buffer.size < sizeof(*syscall_comm)) {
296 ERR("Failed to initialize from malformed event rule syscall: buffer too short to contain header");
297 ret = -1;
298 goto end;
299 }
300
301 current_buffer_view = lttng_buffer_view_from_view(
302 &view->buffer, offset, sizeof(*syscall_comm));
303 if (!lttng_buffer_view_is_valid(&current_buffer_view)) {
304 ret = -1;
305 goto end;
306 }
307
308 syscall_comm = (typeof(syscall_comm)) current_buffer_view.data;
309 rule = lttng_event_rule_syscall_create();
310 if (!rule) {
311 ERR("Failed to create event rule syscall");
312 ret = -1;
313 goto end;
314 }
315
316 /* Skip to payload. */
317 offset += current_buffer_view.size;
318
319 /* Map the pattern. */
320 current_buffer_view = lttng_buffer_view_from_view(
321 &view->buffer, offset, syscall_comm->pattern_len);
322 if (!lttng_buffer_view_is_valid(&current_buffer_view)) {
323 ret = -1;
324 goto end;
325 }
326
327 pattern = current_buffer_view.data;
328 if (!lttng_buffer_view_contains_string(&current_buffer_view, pattern,
329 syscall_comm->pattern_len)) {
330 ret = -1;
331 goto end;
332 }
333
334 /* Skip after the pattern. */
335 offset += syscall_comm->pattern_len;
336
337 if (!syscall_comm->filter_expression_len) {
338 goto skip_filter_expression;
339 }
340
341 /* Map the filter_expression. */
342 current_buffer_view = lttng_buffer_view_from_view(&view->buffer, offset,
343 syscall_comm->filter_expression_len);
344 if (!lttng_buffer_view_is_valid(&current_buffer_view)) {
345 ret = -1;
346 goto end;
347 }
348
349 filter_expression = current_buffer_view.data;
350 if (!lttng_buffer_view_contains_string(&current_buffer_view,
351 filter_expression,
352 syscall_comm->filter_expression_len)) {
353 ret = -1;
354 goto end;
355 }
356
357 /* Skip after the pattern. */
358 offset += syscall_comm->filter_expression_len;
359
360 skip_filter_expression:
361
362 status = lttng_event_rule_syscall_set_pattern(rule, pattern);
363 if (status != LTTNG_EVENT_RULE_STATUS_OK) {
364 ERR("Failed to set event rule syscall pattern");
365 ret = -1;
366 goto end;
367 }
368
369 if (filter_expression) {
370 status = lttng_event_rule_syscall_set_filter(
371 rule, filter_expression);
372 if (status != LTTNG_EVENT_RULE_STATUS_OK) {
373 ERR("Failed to set event rule syscall pattern");
374 ret = -1;
375 goto end;
376 }
377 }
378
379 *_event_rule = rule;
380 rule = NULL;
381 ret = offset;
382 end:
383 lttng_event_rule_destroy(rule);
384 return ret;
385 }
386
387 enum lttng_event_rule_status lttng_event_rule_syscall_set_pattern(
388 struct lttng_event_rule *rule, const char *pattern)
389 {
390 char *pattern_copy = NULL;
391 struct lttng_event_rule_syscall *syscall;
392 enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK;
393
394 if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !pattern ||
395 strlen(pattern) == 0) {
396 status = LTTNG_EVENT_RULE_STATUS_INVALID;
397 goto end;
398 }
399
400 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
401 pattern_copy = strdup(pattern);
402 if (!pattern_copy) {
403 status = LTTNG_EVENT_RULE_STATUS_ERROR;
404 goto end;
405 }
406
407 if (syscall->pattern) {
408 free(syscall->pattern);
409 }
410
411 syscall->pattern = pattern_copy;
412 pattern_copy = NULL;
413 end:
414 return status;
415 }
416
417 enum lttng_event_rule_status lttng_event_rule_syscall_get_pattern(
418 const struct lttng_event_rule *rule, const char **pattern)
419 {
420 struct lttng_event_rule_syscall *syscall;
421 enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK;
422
423 if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !pattern) {
424 status = LTTNG_EVENT_RULE_STATUS_INVALID;
425 goto end;
426 }
427
428 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
429 if (!syscall->pattern) {
430 status = LTTNG_EVENT_RULE_STATUS_UNSET;
431 goto end;
432 }
433
434 *pattern = syscall->pattern;
435 end:
436 return status;
437 }
438
439 enum lttng_event_rule_status lttng_event_rule_syscall_set_filter(
440 struct lttng_event_rule *rule, const char *expression)
441 {
442 char *expression_copy = NULL;
443 struct lttng_event_rule_syscall *syscall;
444 enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK;
445
446 /* TODO: validate that the passed expression is valid. */
447
448 if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !expression ||
449 strlen(expression) == 0) {
450 status = LTTNG_EVENT_RULE_STATUS_INVALID;
451 goto end;
452 }
453
454 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
455 expression_copy = strdup(expression);
456 if (!expression_copy) {
457 status = LTTNG_EVENT_RULE_STATUS_ERROR;
458 goto end;
459 }
460
461 if (syscall->filter_expression) {
462 free(syscall->filter_expression);
463 }
464
465 syscall->filter_expression = expression_copy;
466 expression_copy = NULL;
467 end:
468 return status;
469 }
470
471 enum lttng_event_rule_status lttng_event_rule_syscall_get_filter(
472 const struct lttng_event_rule *rule, const char **expression)
473 {
474 struct lttng_event_rule_syscall *syscall;
475 enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK;
476
477 if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !expression) {
478 status = LTTNG_EVENT_RULE_STATUS_INVALID;
479 goto end;
480 }
481
482 syscall = container_of(rule, struct lttng_event_rule_syscall, parent);
483 if (!syscall->filter_expression) {
484 status = LTTNG_EVENT_RULE_STATUS_UNSET;
485 goto end;
486 }
487
488 *expression = syscall->filter_expression;
489 end:
490 return status;
491 }
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