| 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 | } |