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5024c2ac 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/error.h> | |
10 | #include <common/macros.h> | |
11 | #include <common/runas.h> | |
12 | #include <ctype.h> | |
13 | #include <lttng/constant.h> | |
14 | #include <lttng/event-rule/event-rule-internal.h> | |
15 | #include <lttng/event-rule/kprobe-internal.h> | |
16 | #include <stdio.h> | |
17 | ||
18 | #define IS_KPROBE_EVENT_RULE(rule) \ | |
19 | (lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_KPROBE) | |
20 | ||
21 | #if (LTTNG_SYMBOL_NAME_LEN == 256) | |
22 | #define LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API "255" | |
23 | #endif | |
24 | ||
25 | static void lttng_event_rule_kprobe_destroy(struct lttng_event_rule *rule) | |
26 | { | |
27 | struct lttng_event_rule_kprobe *kprobe; | |
28 | ||
29 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
30 | ||
31 | free(kprobe->name); | |
32 | free(kprobe->probe.symbol_name); | |
33 | free(kprobe); | |
34 | } | |
35 | ||
36 | static bool lttng_event_rule_kprobe_validate( | |
37 | const struct lttng_event_rule *rule) | |
38 | { | |
39 | bool valid = false; | |
40 | struct lttng_event_rule_kprobe *kprobe; | |
41 | ||
42 | if (!rule) { | |
43 | goto end; | |
44 | } | |
45 | ||
46 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
47 | ||
48 | /* Required field */ | |
49 | if (!kprobe->name) { | |
50 | ERR("Invalid name event rule: a name must be set."); | |
51 | goto end; | |
52 | } | |
53 | if (kprobe->probe.set == LTTNG_DOMAIN_NONE) { | |
54 | ERR("Invalid kprobe event rule: a source must be set."); | |
55 | goto end; | |
56 | } | |
57 | ||
58 | valid = true; | |
59 | end: | |
60 | return valid; | |
61 | } | |
62 | ||
63 | static int lttng_event_rule_kprobe_serialize( | |
64 | const struct lttng_event_rule *rule, | |
65 | struct lttng_dynamic_buffer *buf, | |
66 | int *fd_to_send) | |
67 | { | |
68 | int ret; | |
69 | size_t name_len, probe_symbol_name_len; | |
70 | struct lttng_event_rule_kprobe *kprobe; | |
71 | struct lttng_event_rule_kprobe_comm kprobe_comm; | |
72 | ||
73 | if (!rule || !IS_KPROBE_EVENT_RULE(rule)) { | |
74 | ret = -1; | |
75 | goto end; | |
76 | } | |
77 | ||
78 | DBG("Serializing kprobe event rule"); | |
79 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
80 | ||
81 | name_len = strlen(kprobe->name) + 1; | |
82 | ||
83 | if (kprobe->probe.symbol_name != NULL) { | |
84 | probe_symbol_name_len = strlen(kprobe->probe.symbol_name) + 1; | |
85 | } else { | |
86 | probe_symbol_name_len = 0; | |
87 | } | |
88 | ||
89 | kprobe_comm.name_len = name_len; | |
90 | kprobe_comm.probe_symbol_name_len = probe_symbol_name_len; | |
91 | kprobe_comm.probe_address = kprobe->probe.address; | |
92 | kprobe_comm.probe_offset = kprobe->probe.offset; | |
93 | ||
94 | ret = lttng_dynamic_buffer_append( | |
95 | buf, &kprobe_comm, sizeof(kprobe_comm)); | |
96 | if (ret) { | |
97 | goto end; | |
98 | } | |
99 | ret = lttng_dynamic_buffer_append(buf, kprobe->name, name_len); | |
100 | if (ret) { | |
101 | goto end; | |
102 | } | |
103 | ret = lttng_dynamic_buffer_append( | |
104 | buf, kprobe->probe.symbol_name, probe_symbol_name_len); | |
105 | if (ret) { | |
106 | goto end; | |
107 | } | |
108 | ||
109 | if (fd_to_send) { | |
110 | /* Nothing to send */ | |
111 | *fd_to_send = -1; | |
112 | } | |
113 | end: | |
114 | return ret; | |
115 | } | |
116 | ||
117 | static bool lttng_event_rule_kprobe_is_equal(const struct lttng_event_rule *_a, | |
118 | const struct lttng_event_rule *_b) | |
119 | { | |
120 | bool is_equal = false; | |
121 | struct lttng_event_rule_kprobe *a, *b; | |
122 | ||
123 | a = container_of(_a, struct lttng_event_rule_kprobe, parent); | |
124 | b = container_of(_b, struct lttng_event_rule_kprobe, parent); | |
125 | ||
126 | /* Quick checks */ | |
127 | if (!!a->name != !!b->name) { | |
128 | goto end; | |
129 | } | |
130 | ||
131 | if (!!a->probe.symbol_name != !!b->probe.symbol_name) { | |
132 | goto end; | |
133 | } | |
134 | ||
135 | /* Long check */ | |
136 | /* kprobe is invalid if this is not true */ | |
137 | /* TODO: validate that a kprobe MUST have a name */ | |
138 | assert(a->name); | |
139 | assert(b->name); | |
140 | if (strcmp(a->name, b->name)) { | |
141 | goto end; | |
142 | } | |
143 | ||
144 | if (a->probe.symbol_name) { | |
145 | /* Both have symbol name due to previous checks */ | |
146 | if (strcmp(a->probe.symbol_name, b->probe.symbol_name)) { | |
147 | goto end; | |
148 | } | |
149 | } | |
150 | ||
151 | if (a->probe.offset != b->probe.offset) { | |
152 | goto end; | |
153 | } | |
154 | ||
155 | if (a->probe.address != b->probe.address) { | |
156 | goto end; | |
157 | } | |
158 | ||
159 | is_equal = true; | |
160 | end: | |
161 | return is_equal; | |
162 | } | |
163 | ||
164 | static enum lttng_error_code lttng_event_rule_kprobe_populate( | |
165 | struct lttng_event_rule *rule, uid_t uid, gid_t gid) | |
166 | { | |
167 | /* Nothing to do */ | |
168 | return LTTNG_OK; | |
169 | } | |
170 | ||
171 | static const char *lttng_event_rule_kprobe_get_filter( | |
172 | const struct lttng_event_rule *rule) | |
173 | { | |
174 | /* Not supported */ | |
175 | return NULL; | |
176 | } | |
177 | ||
178 | static const struct lttng_bytecode * | |
179 | lttng_event_rule_kprobe_get_filter_bytecode(const struct lttng_event_rule *rule) | |
180 | { | |
181 | /* Not supported */ | |
182 | return NULL; | |
183 | } | |
184 | ||
185 | static struct lttng_event_exclusion * | |
186 | lttng_event_rule_kprobe_generate_exclusions(struct lttng_event_rule *rule) | |
187 | { | |
188 | /* Not supported */ | |
189 | return NULL; | |
190 | } | |
191 | ||
192 | struct lttng_event_rule *lttng_event_rule_kprobe_create() | |
193 | { | |
194 | struct lttng_event_rule_kprobe *rule; | |
195 | ||
196 | rule = zmalloc(sizeof(struct lttng_event_rule_kprobe)); | |
197 | if (!rule) { | |
198 | return NULL; | |
199 | } | |
200 | ||
201 | lttng_event_rule_init(&rule->parent, LTTNG_EVENT_RULE_TYPE_KPROBE); | |
202 | rule->parent.validate = lttng_event_rule_kprobe_validate; | |
203 | rule->parent.serialize = lttng_event_rule_kprobe_serialize; | |
204 | rule->parent.equal = lttng_event_rule_kprobe_is_equal; | |
205 | rule->parent.destroy = lttng_event_rule_kprobe_destroy; | |
206 | rule->parent.populate = lttng_event_rule_kprobe_populate; | |
207 | rule->parent.get_filter = lttng_event_rule_kprobe_get_filter; | |
208 | rule->parent.get_filter_bytecode = | |
209 | lttng_event_rule_kprobe_get_filter_bytecode; | |
210 | rule->parent.generate_exclusions = | |
211 | lttng_event_rule_kprobe_generate_exclusions; | |
212 | return &rule->parent; | |
213 | } | |
214 | ||
215 | LTTNG_HIDDEN | |
216 | ssize_t lttng_event_rule_kprobe_create_from_buffer( | |
217 | const struct lttng_buffer_view *view, | |
218 | struct lttng_event_rule **_event_rule) | |
219 | { | |
220 | ssize_t ret, offset = 0; | |
221 | enum lttng_event_rule_status status; | |
222 | const struct lttng_event_rule_kprobe_comm *kprobe_comm; | |
223 | const char *name; | |
224 | const char *probe_symbol_name = NULL; | |
225 | struct lttng_buffer_view current_view; | |
226 | struct lttng_event_rule *rule = NULL; | |
227 | struct lttng_event_rule_kprobe *kprobe = NULL; | |
228 | ||
229 | if (!_event_rule) { | |
230 | ret = -1; | |
231 | goto end; | |
232 | } | |
233 | ||
234 | if (view->size < sizeof(*kprobe_comm)) { | |
235 | ERR("Failed to initialize from malformed event rule kprobe: buffer too short to contain header"); | |
236 | ret = -1; | |
237 | goto end; | |
238 | } | |
239 | ||
240 | current_view = lttng_buffer_view_from_view( | |
241 | view, offset, sizeof(*kprobe_comm)); | |
242 | kprobe_comm = (typeof(kprobe_comm)) current_view.data; | |
243 | if (!kprobe_comm) { | |
244 | ret = -1; | |
245 | goto end; | |
246 | } | |
247 | ||
248 | rule = lttng_event_rule_kprobe_create(); | |
249 | if (!rule) { | |
250 | ERR("Failed to create event rule kprobe"); | |
251 | ret = -1; | |
252 | goto end; | |
253 | } | |
254 | ||
255 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
256 | ||
257 | /* Skip to payload */ | |
258 | offset += current_view.size; | |
259 | /* Map the name */ | |
260 | current_view = lttng_buffer_view_from_view( | |
261 | view, offset, kprobe_comm->name_len); | |
262 | name = current_view.data; | |
263 | if (!name) { | |
264 | ret = -1; | |
265 | goto end; | |
266 | } | |
267 | ||
268 | if (kprobe_comm->name_len == 1 || | |
269 | name[kprobe_comm->name_len - 1] != '\0' || | |
270 | strlen(name) != kprobe_comm->name_len - 1) { | |
271 | /* | |
272 | * Check that the name is not NULL, is NULL-terminated, and | |
273 | * does not contain a NULL before the last byte. | |
274 | */ | |
275 | ret = -1; | |
276 | goto end; | |
277 | } | |
278 | ||
279 | /* Skip after the name */ | |
280 | offset += kprobe_comm->name_len; | |
281 | if (!kprobe_comm->probe_symbol_name_len) { | |
282 | goto skip_probe_symbol_name; | |
283 | } | |
284 | ||
285 | /* Map the probe_symbol_name */ | |
286 | current_view = lttng_buffer_view_from_view( | |
287 | view, offset, kprobe_comm->probe_symbol_name_len); | |
288 | probe_symbol_name = current_view.data; | |
289 | if (!probe_symbol_name) { | |
290 | ret = -1; | |
291 | goto end; | |
292 | } | |
293 | ||
294 | if (kprobe_comm->probe_symbol_name_len == 1 || | |
295 | probe_symbol_name[kprobe_comm->probe_symbol_name_len - | |
296 | 1] != '\0' || | |
297 | strlen(probe_symbol_name) != | |
298 | kprobe_comm->probe_symbol_name_len - | |
299 | 1) { | |
300 | /* | |
301 | * Check that the filter expression is not NULL, is | |
302 | * NULL-terminated, and does not contain a NULL before the last | |
303 | * byte. | |
304 | */ | |
305 | ret = -1; | |
306 | goto end; | |
307 | } | |
308 | ||
309 | /* Skip after the pattern */ | |
310 | offset += kprobe_comm->probe_symbol_name_len; | |
311 | ||
312 | skip_probe_symbol_name: | |
313 | ||
314 | status = lttng_event_rule_kprobe_set_name(rule, name); | |
315 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
316 | ERR("Failed to set event rule kprobe name"); | |
317 | ret = -1; | |
318 | goto end; | |
319 | } | |
320 | kprobe->probe.offset = kprobe_comm->probe_offset; | |
321 | kprobe->probe.address = kprobe_comm->probe_address; | |
322 | if (probe_symbol_name) { | |
323 | kprobe->probe.symbol_name = strdup(probe_symbol_name); | |
324 | if (!kprobe->probe.symbol_name) { | |
325 | ERR("Failed to set event rule kprobe probe symbol name"); | |
326 | ret = -1; | |
327 | goto end; | |
328 | } | |
329 | } | |
330 | ||
331 | *_event_rule = rule; | |
332 | rule = NULL; | |
333 | ret = offset; | |
334 | end: | |
335 | lttng_event_rule_destroy(rule); | |
336 | return ret; | |
337 | } | |
338 | ||
339 | enum lttng_event_rule_status lttng_event_rule_kprobe_set_source( | |
340 | struct lttng_event_rule *rule, const char *source) | |
341 | { | |
342 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
343 | int match; | |
344 | char s_hex[19]; | |
345 | char name[LTTNG_SYMBOL_NAME_LEN]; | |
346 | struct lttng_event_rule_kprobe *kprobe; | |
347 | ||
348 | /* TODO: support multiple call for this, we must free the symbol name if | |
349 | * that happens !!! | |
350 | */ | |
351 | ||
352 | if (!source || !IS_KPROBE_EVENT_RULE(rule) || !rule) { | |
353 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
354 | goto end; | |
355 | } | |
356 | ||
357 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
358 | ||
359 | /* Check for symbol+offset */ | |
360 | match = sscanf(source, "%18s[^'+']+%18s", name, s_hex); | |
361 | if (match == 2) { | |
362 | /* TODO double validate termination handling of this */ | |
363 | kprobe->probe.symbol_name = | |
364 | strndup(name, LTTNG_SYMBOL_NAME_LEN); | |
365 | if (!kprobe->probe.symbol_name) { | |
366 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
367 | goto end; | |
368 | } | |
369 | if (*s_hex == '\0') { | |
370 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
371 | goto end; | |
372 | } | |
373 | kprobe->probe.offset = strtoul(s_hex, NULL, 0); | |
374 | kprobe->probe.address = 0; | |
375 | kprobe->probe.set = true; | |
376 | goto end; | |
377 | } | |
378 | ||
379 | /* Check for symbol */ | |
380 | if (isalpha(name[0]) || name[0] == '_') { | |
381 | match = sscanf(source, | |
382 | "%" LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API | |
383 | "s", | |
384 | name); | |
385 | if (match == 1) { | |
386 | /* TODO double validate termination handling of this */ | |
387 | kprobe->probe.symbol_name = | |
388 | strndup(name, LTTNG_SYMBOL_NAME_LEN); | |
389 | if (!kprobe->probe.symbol_name) { | |
390 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
391 | goto end; | |
392 | } | |
393 | kprobe->probe.offset = 0; | |
394 | kprobe->probe.address = 0; | |
395 | kprobe->probe.set = true; | |
396 | goto end; | |
397 | } | |
398 | } | |
399 | ||
400 | /* Check for address */ | |
401 | match = sscanf(source, "%18s", s_hex); | |
402 | if (match > 0) { | |
403 | if (*s_hex == '\0') { | |
404 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
405 | goto end; | |
406 | } | |
407 | kprobe->probe.address = strtoul(s_hex, NULL, 0); | |
408 | kprobe->probe.offset = 0; | |
409 | kprobe->probe.symbol_name = NULL; | |
410 | kprobe->probe.set = true; | |
411 | goto end; | |
412 | } | |
413 | ||
414 | /* No match */ | |
415 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
416 | ||
417 | end: | |
418 | return status; | |
419 | } | |
420 | ||
421 | enum lttng_event_rule_status lttng_event_rule_kprobe_set_name( | |
422 | struct lttng_event_rule *rule, const char *name) | |
423 | { | |
424 | char *name_copy = NULL; | |
425 | struct lttng_event_rule_kprobe *kprobe; | |
426 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
427 | ||
428 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !name || | |
429 | strlen(name) == 0) { | |
430 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
431 | goto end; | |
432 | } | |
433 | ||
434 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
435 | name_copy = strdup(name); | |
436 | if (!name_copy) { | |
437 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
438 | goto end; | |
439 | } | |
440 | ||
441 | if (kprobe->name) { | |
442 | free(kprobe->name); | |
443 | } | |
444 | ||
445 | kprobe->name = name_copy; | |
446 | name_copy = NULL; | |
447 | end: | |
448 | return status; | |
449 | } | |
450 | ||
451 | enum lttng_event_rule_status lttng_event_rule_kprobe_get_name( | |
452 | const struct lttng_event_rule *rule, const char **name) | |
453 | { | |
454 | struct lttng_event_rule_kprobe *kprobe; | |
455 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
456 | ||
457 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !name) { | |
458 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
459 | goto end; | |
460 | } | |
461 | ||
462 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
463 | if (!kprobe->name) { | |
464 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
465 | goto end; | |
466 | } | |
467 | ||
468 | *name = kprobe->name; | |
469 | end: | |
470 | return status; | |
471 | } | |
472 | ||
473 | LTTNG_HIDDEN | |
474 | uint64_t lttng_event_rule_kprobe_get_address( | |
475 | const struct lttng_event_rule *rule) | |
476 | { | |
477 | struct lttng_event_rule_kprobe *kprobe; | |
478 | ||
479 | assert(rule && IS_KPROBE_EVENT_RULE(rule)); | |
480 | ||
481 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
482 | ||
483 | return kprobe->probe.address; | |
484 | } | |
485 | ||
486 | LTTNG_HIDDEN | |
487 | uint64_t lttng_event_rule_kprobe_get_offset(const struct lttng_event_rule *rule) | |
488 | { | |
489 | struct lttng_event_rule_kprobe *kprobe; | |
490 | ||
491 | assert(rule && IS_KPROBE_EVENT_RULE(rule)); | |
492 | ||
493 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
494 | return kprobe->probe.offset; | |
495 | } | |
496 | ||
497 | LTTNG_HIDDEN | |
498 | const char *lttng_event_rule_kprobe_get_symbol_name( | |
499 | const struct lttng_event_rule *rule) | |
500 | { | |
501 | struct lttng_event_rule_kprobe *kprobe; | |
502 | ||
503 | assert(rule && IS_KPROBE_EVENT_RULE(rule)); | |
504 | ||
505 | kprobe = container_of(rule, struct lttng_event_rule_kprobe, parent); | |
506 | return kprobe->probe.symbol_name; | |
507 | } |