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1831ae68 FD |
1 | /* |
2 | * Copyright (C) 2019 - Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU Lesser General Public License, version 2.1 only, | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
11 | * for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU Lesser General Public License | |
14 | * along with this library; if not, write to the Free Software Foundation, | |
15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
18 | #include <lttng/constant.h> | |
19 | #include <lttng/event-rule/event-rule-internal.h> | |
20 | #include <lttng/event-rule/kprobe-internal.h> | |
21 | #include <common/macros.h> | |
22 | #include <common/error.h> | |
23 | #include <common/runas.h> | |
24 | #include <assert.h> | |
25 | #include <stdio.h> | |
26 | #include <ctype.h> | |
27 | ||
28 | #define IS_KPROBE_EVENT_RULE(rule) ( \ | |
29 | lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_KPROBE \ | |
30 | ) | |
31 | ||
32 | #if (LTTNG_SYMBOL_NAME_LEN == 256) | |
33 | #define LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API "255" | |
34 | #endif | |
35 | ||
36 | static | |
37 | void lttng_event_rule_kprobe_destroy(struct lttng_event_rule *rule) | |
38 | { | |
39 | struct lttng_event_rule_kprobe *kprobe; | |
40 | ||
41 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, | |
42 | parent); | |
43 | ||
44 | free(kprobe->name); | |
45 | free(kprobe->probe.symbol_name); | |
46 | free(kprobe); | |
47 | } | |
48 | ||
49 | static | |
50 | bool lttng_event_rule_kprobe_validate( | |
51 | const struct lttng_event_rule *rule) | |
52 | { | |
53 | bool valid = false; | |
54 | struct lttng_event_rule_kprobe *kprobe; | |
55 | ||
56 | if (!rule) { | |
57 | goto end; | |
58 | } | |
59 | ||
60 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
61 | ||
62 | /* Required field */ | |
63 | if (!kprobe->name) { | |
64 | ERR("Invalid name event rule: a name must be set."); | |
65 | goto end; | |
66 | } | |
67 | if (kprobe->probe.set == LTTNG_DOMAIN_NONE) { | |
68 | ERR("Invalid kprobe event rule: a source must be set."); | |
69 | goto end; | |
70 | } | |
71 | ||
72 | valid = true; | |
73 | end: | |
74 | return valid; | |
75 | } | |
76 | ||
77 | static | |
78 | int lttng_event_rule_kprobe_serialize( | |
79 | const struct lttng_event_rule *rule, | |
80 | struct lttng_dynamic_buffer *buf, | |
81 | int *fd_to_send) | |
82 | { | |
83 | int ret; | |
84 | size_t name_len, probe_symbol_name_len; | |
85 | struct lttng_event_rule_kprobe *kprobe; | |
86 | struct lttng_event_rule_kprobe_comm kprobe_comm; | |
87 | ||
88 | if (!rule || !IS_KPROBE_EVENT_RULE(rule)) { | |
89 | ret = -1; | |
90 | goto end; | |
91 | } | |
92 | ||
93 | DBG("Serializing kprobe event rule"); | |
94 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
95 | ||
96 | name_len = strlen(kprobe->name) + 1; | |
97 | ||
98 | if (kprobe->probe.symbol_name != NULL) { | |
99 | probe_symbol_name_len = strlen(kprobe->probe.symbol_name) + 1; | |
100 | } else { | |
101 | probe_symbol_name_len = 0; | |
102 | } | |
103 | ||
104 | kprobe_comm.name_len = name_len; | |
105 | kprobe_comm.probe_symbol_name_len = probe_symbol_name_len; | |
106 | kprobe_comm.probe_address = kprobe->probe.address; | |
107 | kprobe_comm.probe_offset = kprobe->probe.offset; | |
108 | ||
109 | ret = lttng_dynamic_buffer_append( | |
110 | buf, &kprobe_comm, sizeof(kprobe_comm)); | |
111 | if (ret) { | |
112 | goto end; | |
113 | } | |
114 | ret = lttng_dynamic_buffer_append(buf, kprobe->name, name_len); | |
115 | if (ret) { | |
116 | goto end; | |
117 | } | |
118 | ret = lttng_dynamic_buffer_append( | |
119 | buf, kprobe->probe.symbol_name, probe_symbol_name_len); | |
120 | if (ret) { | |
121 | goto end; | |
122 | } | |
123 | ||
124 | if (fd_to_send) { | |
125 | /* Nothing to send */ | |
126 | *fd_to_send = -1; | |
127 | } | |
128 | end: | |
129 | return ret; | |
130 | } | |
131 | ||
132 | static | |
133 | bool lttng_event_rule_kprobe_is_equal(const struct lttng_event_rule *_a, | |
134 | const struct lttng_event_rule *_b) | |
135 | { | |
136 | bool is_equal = false; | |
137 | struct lttng_event_rule_kprobe *a, *b; | |
138 | ||
139 | a = container_of(_a, struct lttng_event_rule_kprobe, parent); | |
140 | b = container_of(_b, struct lttng_event_rule_kprobe, parent); | |
141 | ||
142 | /* Quick checks */ | |
143 | if (!!a->name != !!b->name) { | |
144 | goto end; | |
145 | } | |
146 | ||
147 | if (!!a->probe.symbol_name != !!b->probe.symbol_name) { | |
148 | goto end; | |
149 | } | |
150 | ||
151 | /* Long check */ | |
152 | /* kprobe is invalid if this is not true */ | |
153 | /* TODO: validate that a kprobe MUST have a name */ | |
154 | assert(a->name); | |
155 | assert(b->name); | |
156 | if (strcmp(a->name, b->name)) { | |
157 | goto end; | |
158 | } | |
159 | ||
160 | if (a->probe.symbol_name) { | |
161 | /* Both have symbol name due to previous checks */ | |
162 | if (strcmp(a->probe.symbol_name, b->probe.symbol_name)) { | |
163 | goto end; | |
164 | } | |
165 | } | |
166 | ||
167 | if (a->probe.offset != b->probe.offset) { | |
168 | goto end; | |
169 | } | |
170 | ||
171 | if (a->probe.address != b->probe.address) { | |
172 | goto end; | |
173 | } | |
174 | ||
175 | is_equal = true; | |
176 | end: | |
177 | return is_equal; | |
178 | } | |
179 | ||
180 | static | |
181 | enum lttng_error_code lttng_event_rule_kprobe_populate(struct lttng_event_rule *rule, uid_t uid, gid_t gid) | |
182 | { | |
183 | /* Nothing to do */ | |
184 | return LTTNG_OK; | |
185 | } | |
186 | ||
187 | static const char *lttng_event_rule_kprobe_get_filter( | |
188 | const struct lttng_event_rule *rule) | |
189 | { | |
190 | /* Not supported */ | |
191 | return NULL; | |
192 | } | |
193 | ||
194 | static const struct lttng_filter_bytecode * | |
195 | lttng_event_rule_kprobe_get_filter_bytecode(const struct lttng_event_rule *rule) | |
196 | { | |
197 | /* Not supported */ | |
198 | return NULL; | |
199 | } | |
200 | ||
201 | static | |
202 | struct lttng_event_exclusion *lttng_event_rule_kprobe_generate_exclusions(struct lttng_event_rule *rule) | |
203 | { | |
204 | /* Not supported */ | |
205 | return NULL; | |
206 | } | |
207 | ||
208 | struct lttng_event_rule *lttng_event_rule_kprobe_create() | |
209 | { | |
210 | struct lttng_event_rule_kprobe *rule; | |
211 | ||
212 | rule = zmalloc(sizeof(struct lttng_event_rule_kprobe)); | |
213 | if (!rule) { | |
214 | return NULL; | |
215 | } | |
216 | ||
217 | lttng_event_rule_init(&rule->parent, LTTNG_EVENT_RULE_TYPE_KPROBE); | |
218 | rule->parent.validate = lttng_event_rule_kprobe_validate; | |
219 | rule->parent.serialize = lttng_event_rule_kprobe_serialize; | |
220 | rule->parent.equal = lttng_event_rule_kprobe_is_equal; | |
221 | rule->parent.destroy = lttng_event_rule_kprobe_destroy; | |
222 | rule->parent.populate = lttng_event_rule_kprobe_populate; | |
223 | rule->parent.get_filter = lttng_event_rule_kprobe_get_filter; | |
224 | rule->parent.get_filter_bytecode = lttng_event_rule_kprobe_get_filter_bytecode; | |
225 | rule->parent.generate_exclusions = lttng_event_rule_kprobe_generate_exclusions; | |
226 | return &rule->parent; | |
227 | } | |
228 | ||
229 | LTTNG_HIDDEN | |
230 | ssize_t lttng_event_rule_kprobe_create_from_buffer( | |
231 | const struct lttng_buffer_view *view, | |
232 | struct lttng_event_rule **_event_rule) | |
233 | { | |
234 | ssize_t ret, offset = 0; | |
235 | enum lttng_event_rule_status status; | |
236 | const struct lttng_event_rule_kprobe_comm *kprobe_comm; | |
237 | const char *name; | |
238 | const char *probe_symbol_name = NULL; | |
239 | struct lttng_buffer_view current_view; | |
240 | struct lttng_event_rule *rule = NULL; | |
241 | struct lttng_event_rule_kprobe *kprobe = NULL; | |
242 | ||
243 | if (!_event_rule) { | |
244 | ret = -1; | |
245 | goto end; | |
246 | } | |
247 | ||
248 | if (view->size < sizeof(*kprobe_comm)) { | |
249 | ERR("Failed to initialize from malformed event rule kprobe: buffer too short to contain header"); | |
250 | ret = -1; | |
251 | goto end; | |
252 | } | |
253 | ||
254 | current_view = lttng_buffer_view_from_view( | |
255 | view, offset, sizeof(*kprobe_comm)); | |
256 | kprobe_comm = (typeof(kprobe_comm)) current_view.data; | |
257 | if (!kprobe_comm) { | |
258 | ret = -1; | |
259 | goto end; | |
260 | } | |
261 | ||
262 | rule = lttng_event_rule_kprobe_create(); | |
263 | if (!rule) { | |
264 | ERR("Failed to create event rule kprobe"); | |
265 | ret = -1; | |
266 | goto end; | |
267 | } | |
268 | ||
269 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
270 | ||
271 | /* Skip to payload */ | |
272 | offset += current_view.size; | |
273 | /* Map the name */ | |
274 | current_view = lttng_buffer_view_from_view( | |
275 | view, offset, kprobe_comm->name_len); | |
276 | name = current_view.data; | |
277 | if (!name) { | |
278 | ret = -1; | |
279 | goto end; | |
280 | } | |
281 | ||
282 | if (kprobe_comm->name_len == 1 || | |
283 | name[kprobe_comm->name_len - 1] != '\0' || | |
284 | strlen(name) != kprobe_comm->name_len - 1) { | |
285 | /* | |
286 | * Check that the name is not NULL, is NULL-terminated, and | |
287 | * does not contain a NULL before the last byte. | |
288 | */ | |
289 | ret = -1; | |
290 | goto end; | |
291 | } | |
292 | ||
293 | /* Skip after the name */ | |
294 | offset += kprobe_comm->name_len; | |
295 | if (!kprobe_comm->probe_symbol_name_len) { | |
296 | goto skip_probe_symbol_name; | |
297 | } | |
298 | ||
299 | /* Map the probe_symbol_name */ | |
300 | current_view = lttng_buffer_view_from_view( | |
301 | view, offset, kprobe_comm->probe_symbol_name_len); | |
302 | probe_symbol_name = current_view.data; | |
303 | if (!probe_symbol_name) { | |
304 | ret = -1; | |
305 | goto end; | |
306 | } | |
307 | ||
308 | if (kprobe_comm->probe_symbol_name_len == 1 || | |
309 | probe_symbol_name[kprobe_comm->probe_symbol_name_len - | |
310 | 1] != '\0' || | |
311 | strlen(probe_symbol_name) != | |
312 | kprobe_comm->probe_symbol_name_len - | |
313 | 1) { | |
314 | /* | |
315 | * Check that the filter expression is not NULL, is | |
316 | * NULL-terminated, and does not contain a NULL before the last | |
317 | * byte. | |
318 | */ | |
319 | ret = -1; | |
320 | goto end; | |
321 | } | |
322 | ||
323 | /* Skip after the pattern */ | |
324 | offset += kprobe_comm->probe_symbol_name_len; | |
325 | ||
326 | skip_probe_symbol_name: | |
327 | ||
328 | status = lttng_event_rule_kprobe_set_name(rule, name); | |
329 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
330 | ERR("Failed to set event rule kprobe name"); | |
331 | ret = -1; | |
332 | goto end; | |
333 | } | |
334 | kprobe->probe.offset = kprobe_comm->probe_offset; | |
335 | kprobe->probe.address = kprobe_comm->probe_address; | |
336 | if (probe_symbol_name) { | |
337 | kprobe->probe.symbol_name = strdup(probe_symbol_name); | |
338 | if (!kprobe->probe.symbol_name) { | |
339 | ERR("Failed to set event rule kprobe probe symbol name"); | |
340 | ret = -1; | |
341 | goto end; | |
342 | } | |
343 | } | |
344 | ||
345 | *_event_rule = rule; | |
346 | rule = NULL; | |
347 | ret = offset; | |
348 | end: | |
349 | lttng_event_rule_destroy(rule); | |
350 | return ret; | |
351 | } | |
352 | ||
353 | enum lttng_event_rule_status lttng_event_rule_kprobe_set_source( | |
354 | struct lttng_event_rule *rule, const char *source) | |
355 | { | |
356 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
357 | int match; | |
358 | char s_hex[19]; | |
359 | char name[LTTNG_SYMBOL_NAME_LEN]; | |
360 | struct lttng_event_rule_kprobe *kprobe; | |
361 | ||
362 | /* TODO: support multiple call for this, we must free the symbol name if | |
363 | * that happens !!! | |
364 | */ | |
365 | ||
366 | if (!source || !IS_KPROBE_EVENT_RULE(rule) || !rule) { | |
367 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
368 | goto end; | |
369 | } | |
370 | ||
371 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
372 | ||
373 | /* Check for symbol+offset */ | |
374 | match = sscanf(source, "%18s[^'+']+%18s", name, s_hex); | |
375 | if (match == 2) { | |
376 | /* TODO double validate termination handling of this */ | |
377 | kprobe->probe.symbol_name = | |
378 | strndup(name, LTTNG_SYMBOL_NAME_LEN); | |
379 | if (!kprobe->probe.symbol_name) { | |
380 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
381 | goto end; | |
382 | } | |
383 | if (*s_hex == '\0') { | |
384 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
385 | goto end; | |
386 | } | |
387 | kprobe->probe.offset = strtoul(s_hex, NULL, 0); | |
388 | kprobe->probe.address = 0; | |
389 | kprobe->probe.set = true; | |
390 | goto end; | |
391 | } | |
392 | ||
393 | /* Check for symbol */ | |
394 | if (isalpha(name[0]) || name[0] == '_') { | |
395 | match = sscanf(source, | |
396 | "%" LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API | |
397 | "s", | |
398 | name); | |
399 | if (match == 1) { | |
400 | /* TODO double validate termination handling of this */ | |
401 | kprobe->probe.symbol_name = | |
402 | strndup(name, LTTNG_SYMBOL_NAME_LEN); | |
403 | if (!kprobe->probe.symbol_name) { | |
404 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
405 | goto end; | |
406 | } | |
407 | kprobe->probe.offset = 0; | |
408 | kprobe->probe.address = 0; | |
409 | kprobe->probe.set = true; | |
410 | goto end; | |
411 | } | |
412 | } | |
413 | ||
414 | /* Check for address */ | |
415 | match = sscanf(source, "%18s", s_hex); | |
416 | if (match > 0) { | |
417 | if (*s_hex == '\0') { | |
418 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
419 | goto end; | |
420 | } | |
421 | kprobe->probe.address = strtoul(s_hex, NULL, 0); | |
422 | kprobe->probe.offset = 0; | |
423 | kprobe->probe.symbol_name = NULL; | |
424 | kprobe->probe.set = true; | |
425 | goto end; | |
426 | } | |
427 | ||
428 | /* No match */ | |
429 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
430 | ||
431 | end: | |
432 | return status; | |
433 | } | |
434 | ||
435 | enum lttng_event_rule_status lttng_event_rule_kprobe_set_name( | |
436 | struct lttng_event_rule *rule, const char *name) | |
437 | { | |
438 | char *name_copy = NULL; | |
439 | struct lttng_event_rule_kprobe *kprobe; | |
440 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
441 | ||
442 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !name || | |
443 | strlen(name) == 0) { | |
444 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
445 | goto end; | |
446 | } | |
447 | ||
448 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
449 | name_copy = strdup(name); | |
450 | if (!name_copy) { | |
451 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
452 | goto end; | |
453 | } | |
454 | ||
455 | if (kprobe->name) { | |
456 | free(kprobe->name); | |
457 | } | |
458 | ||
459 | kprobe->name = name_copy; | |
460 | name_copy = NULL; | |
461 | end: | |
462 | return status; | |
463 | } | |
464 | ||
465 | enum lttng_event_rule_status lttng_event_rule_kprobe_get_name( | |
466 | const struct lttng_event_rule *rule, const char **name) | |
467 | { | |
468 | struct lttng_event_rule_kprobe *kprobe; | |
469 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
470 | ||
471 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !name) { | |
472 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
473 | goto end; | |
474 | } | |
475 | ||
476 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
477 | if (!kprobe->name) { | |
478 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
479 | goto end; | |
480 | } | |
481 | ||
482 | *name = kprobe->name; | |
483 | end: | |
484 | return status; | |
485 | } | |
486 | ||
487 | LTTNG_HIDDEN | |
488 | uint64_t lttng_event_rule_kprobe_get_address( | |
489 | const struct lttng_event_rule *rule) | |
490 | { | |
491 | struct lttng_event_rule_kprobe *kprobe; | |
492 | ||
493 | assert(rule && IS_KPROBE_EVENT_RULE(rule)); | |
494 | ||
495 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
496 | ||
497 | return kprobe->probe.address; | |
498 | } | |
499 | ||
500 | LTTNG_HIDDEN | |
501 | uint64_t lttng_event_rule_kprobe_get_offset( | |
502 | const struct lttng_event_rule *rule) | |
503 | { | |
504 | struct lttng_event_rule_kprobe *kprobe; | |
505 | ||
506 | assert(rule && IS_KPROBE_EVENT_RULE(rule)); | |
507 | ||
508 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
509 | return kprobe->probe.offset; | |
510 | } | |
511 | ||
512 | LTTNG_HIDDEN | |
513 | const char *lttng_event_rule_kprobe_get_symbol_name( | |
514 | const struct lttng_event_rule *rule) | |
515 | { | |
516 | struct lttng_event_rule_kprobe *kprobe; | |
517 | ||
518 | assert(rule && IS_KPROBE_EVENT_RULE(rule)); | |
519 | ||
520 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
521 | return kprobe->probe.symbol_name; | |
522 | } |