| 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 <ctype.h> |
| 18 | #include <lttng/constant.h> |
| 19 | #include <lttng/event-rule/event-rule.h> |
| 20 | #include <lttng/event-rule/event-rule-internal.h> |
| 21 | #include <lttng/event-rule/kernel-kprobe-internal.h> |
| 22 | #include <lttng/kernel-probe.h> |
| 23 | #include <lttng/kernel-probe-internal.h> |
| 24 | #include <stdio.h> |
| 25 | |
| 26 | #define IS_KPROBE_EVENT_RULE(rule) \ |
| 27 | (lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_KERNEL_KPROBE) |
| 28 | |
| 29 | #if (LTTNG_SYMBOL_NAME_LEN == 256) |
| 30 | #define LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API "255" |
| 31 | #endif |
| 32 | |
| 33 | static void lttng_event_rule_kernel_kprobe_destroy(struct lttng_event_rule *rule) |
| 34 | { |
| 35 | struct lttng_event_rule_kernel_kprobe *kprobe; |
| 36 | |
| 37 | kprobe = container_of(rule, struct lttng_event_rule_kernel_kprobe, parent); |
| 38 | |
| 39 | lttng_kernel_probe_location_destroy(kprobe->location); |
| 40 | free(kprobe->name); |
| 41 | free(kprobe); |
| 42 | } |
| 43 | |
| 44 | static bool lttng_event_rule_kernel_kprobe_validate( |
| 45 | const struct lttng_event_rule *rule) |
| 46 | { |
| 47 | bool valid = false; |
| 48 | struct lttng_event_rule_kernel_kprobe *kprobe; |
| 49 | |
| 50 | if (!rule) { |
| 51 | goto end; |
| 52 | } |
| 53 | |
| 54 | kprobe = container_of(rule, struct lttng_event_rule_kernel_kprobe, parent); |
| 55 | |
| 56 | /* Required field. */ |
| 57 | if (!kprobe->name) { |
| 58 | ERR("Invalid name event rule: a name must be set."); |
| 59 | goto end; |
| 60 | } |
| 61 | |
| 62 | /* Required field. */ |
| 63 | if(!kprobe->location) { |
| 64 | ERR("Invalid name event rule: a location must be set."); |
| 65 | goto end; |
| 66 | } |
| 67 | |
| 68 | valid = true; |
| 69 | end: |
| 70 | return valid; |
| 71 | } |
| 72 | |
| 73 | static int lttng_event_rule_kernel_kprobe_serialize( |
| 74 | const struct lttng_event_rule *rule, |
| 75 | struct lttng_payload *payload) |
| 76 | { |
| 77 | int ret; |
| 78 | size_t name_len, header_offset, size_before_location; |
| 79 | struct lttng_event_rule_kernel_kprobe *kprobe; |
| 80 | struct lttng_event_rule_kernel_kprobe_comm kprobe_comm; |
| 81 | struct lttng_event_rule_kernel_kprobe_comm *header; |
| 82 | |
| 83 | if (!rule || !IS_KPROBE_EVENT_RULE(rule)) { |
| 84 | ret = -1; |
| 85 | goto end; |
| 86 | } |
| 87 | |
| 88 | header_offset = payload->buffer.size; |
| 89 | |
| 90 | DBG("Serializing kprobe event rule."); |
| 91 | kprobe = container_of(rule, struct lttng_event_rule_kernel_kprobe, parent); |
| 92 | |
| 93 | name_len = strlen(kprobe->name) + 1; |
| 94 | kprobe_comm.name_len = name_len; |
| 95 | |
| 96 | ret = lttng_dynamic_buffer_append( |
| 97 | &payload->buffer, &kprobe_comm, sizeof(kprobe_comm)); |
| 98 | if (ret) { |
| 99 | goto end; |
| 100 | } |
| 101 | |
| 102 | ret = lttng_dynamic_buffer_append(&payload->buffer, kprobe->name, name_len); |
| 103 | if (ret) { |
| 104 | goto end; |
| 105 | } |
| 106 | |
| 107 | size_before_location = payload->buffer.size; |
| 108 | |
| 109 | ret = lttng_kernel_probe_location_serialize(kprobe->location, payload); |
| 110 | if (ret < 0) { |
| 111 | goto end; |
| 112 | } |
| 113 | |
| 114 | /* Update the header regarding the probe size. */ |
| 115 | header = (struct lttng_event_rule_kernel_kprobe_comm*) ( |
| 116 | (char *) payload->buffer.data + header_offset); |
| 117 | header->location_len = payload->buffer.size - size_before_location; |
| 118 | |
| 119 | ret = 0; |
| 120 | |
| 121 | end: |
| 122 | return ret; |
| 123 | } |
| 124 | |
| 125 | static bool lttng_event_rule_kernel_kprobe_is_equal(const struct lttng_event_rule *_a, |
| 126 | const struct lttng_event_rule *_b) |
| 127 | { |
| 128 | bool is_equal = false; |
| 129 | struct lttng_event_rule_kernel_kprobe *a, *b; |
| 130 | |
| 131 | a = container_of(_a, struct lttng_event_rule_kernel_kprobe, parent); |
| 132 | b = container_of(_b, struct lttng_event_rule_kernel_kprobe, parent); |
| 133 | |
| 134 | /* Quick checks */ |
| 135 | if (!!a->name != !!b->name) { |
| 136 | goto end; |
| 137 | } |
| 138 | |
| 139 | /* Long check */ |
| 140 | assert(a->name); |
| 141 | assert(b->name); |
| 142 | if (strcmp(a->name, b->name)) { |
| 143 | goto end; |
| 144 | } |
| 145 | |
| 146 | is_equal = lttng_kernel_probe_location_is_equal( |
| 147 | a->location, b->location); |
| 148 | end: |
| 149 | return is_equal; |
| 150 | } |
| 151 | |
| 152 | static enum lttng_error_code lttng_event_rule_kernel_kprobe_generate_filter_bytecode( |
| 153 | struct lttng_event_rule *rule, |
| 154 | const struct lttng_credentials *creds) |
| 155 | { |
| 156 | /* Nothing to do. */ |
| 157 | return LTTNG_OK; |
| 158 | } |
| 159 | |
| 160 | static const char *lttng_event_rule_kernel_kprobe_get_filter( |
| 161 | const struct lttng_event_rule *rule) |
| 162 | { |
| 163 | /* Not supported. */ |
| 164 | return NULL; |
| 165 | } |
| 166 | |
| 167 | static const struct lttng_bytecode * |
| 168 | lttng_event_rule_kernel_kprobe_get_filter_bytecode(const struct lttng_event_rule *rule) |
| 169 | { |
| 170 | /* Not supported. */ |
| 171 | return NULL; |
| 172 | } |
| 173 | |
| 174 | static enum lttng_event_rule_generate_exclusions_status |
| 175 | lttng_event_rule_kernel_kprobe_generate_exclusions(const struct lttng_event_rule *rule, |
| 176 | struct lttng_event_exclusion **exclusions) |
| 177 | { |
| 178 | /* Not supported. */ |
| 179 | *exclusions = NULL; |
| 180 | return LTTNG_EVENT_RULE_GENERATE_EXCLUSIONS_STATUS_NONE; |
| 181 | } |
| 182 | |
| 183 | static unsigned long |
| 184 | lttng_event_rule_kernel_kprobe_hash( |
| 185 | const struct lttng_event_rule *rule) |
| 186 | { |
| 187 | unsigned long hash; |
| 188 | struct lttng_event_rule_kernel_kprobe *krule = |
| 189 | container_of(rule, typeof(*krule), parent); |
| 190 | |
| 191 | hash = hash_key_ulong((void *) LTTNG_EVENT_RULE_TYPE_KERNEL_KPROBE, |
| 192 | lttng_ht_seed); |
| 193 | hash ^= hash_key_str(krule->name, lttng_ht_seed); |
| 194 | hash ^= lttng_kernel_probe_location_hash(krule->location); |
| 195 | |
| 196 | return hash; |
| 197 | } |
| 198 | |
| 199 | static |
| 200 | int kernel_probe_set_location( |
| 201 | struct lttng_event_rule_kernel_kprobe *kprobe, |
| 202 | const struct lttng_kernel_probe_location *location) |
| 203 | { |
| 204 | int ret; |
| 205 | struct lttng_kernel_probe_location *location_copy = NULL; |
| 206 | |
| 207 | if (!kprobe || !location || kprobe->location) { |
| 208 | ret = -1; |
| 209 | goto end; |
| 210 | } |
| 211 | |
| 212 | location_copy = lttng_kernel_probe_location_copy(location); |
| 213 | if (!location_copy) { |
| 214 | ret = -1; |
| 215 | goto end; |
| 216 | } |
| 217 | |
| 218 | kprobe->location = location_copy; |
| 219 | location_copy = NULL; |
| 220 | ret = 0; |
| 221 | end: |
| 222 | lttng_kernel_probe_location_destroy(location_copy); |
| 223 | return ret; |
| 224 | } |
| 225 | |
| 226 | struct lttng_event_rule *lttng_event_rule_kernel_kprobe_create( |
| 227 | const struct lttng_kernel_probe_location *location) |
| 228 | { |
| 229 | struct lttng_event_rule *rule = NULL; |
| 230 | struct lttng_event_rule_kernel_kprobe *krule; |
| 231 | |
| 232 | krule = zmalloc(sizeof(struct lttng_event_rule_kernel_kprobe)); |
| 233 | if (!krule) { |
| 234 | goto end; |
| 235 | } |
| 236 | |
| 237 | rule = &krule->parent; |
| 238 | lttng_event_rule_init(&krule->parent, LTTNG_EVENT_RULE_TYPE_KERNEL_KPROBE); |
| 239 | krule->parent.validate = lttng_event_rule_kernel_kprobe_validate; |
| 240 | krule->parent.serialize = lttng_event_rule_kernel_kprobe_serialize; |
| 241 | krule->parent.equal = lttng_event_rule_kernel_kprobe_is_equal; |
| 242 | krule->parent.destroy = lttng_event_rule_kernel_kprobe_destroy; |
| 243 | krule->parent.generate_filter_bytecode = |
| 244 | lttng_event_rule_kernel_kprobe_generate_filter_bytecode; |
| 245 | krule->parent.get_filter = lttng_event_rule_kernel_kprobe_get_filter; |
| 246 | krule->parent.get_filter_bytecode = |
| 247 | lttng_event_rule_kernel_kprobe_get_filter_bytecode; |
| 248 | krule->parent.generate_exclusions = |
| 249 | lttng_event_rule_kernel_kprobe_generate_exclusions; |
| 250 | krule->parent.hash = lttng_event_rule_kernel_kprobe_hash; |
| 251 | |
| 252 | if (kernel_probe_set_location(krule, location)) { |
| 253 | lttng_event_rule_destroy(rule); |
| 254 | rule = NULL; |
| 255 | } |
| 256 | |
| 257 | end: |
| 258 | return rule; |
| 259 | } |
| 260 | |
| 261 | LTTNG_HIDDEN |
| 262 | ssize_t lttng_event_rule_kernel_kprobe_create_from_payload( |
| 263 | struct lttng_payload_view *view, |
| 264 | struct lttng_event_rule **_event_rule) |
| 265 | { |
| 266 | ssize_t ret, offset = 0; |
| 267 | enum lttng_event_rule_status status; |
| 268 | const struct lttng_event_rule_kernel_kprobe_comm *kprobe_comm; |
| 269 | const char *name; |
| 270 | struct lttng_buffer_view current_buffer_view; |
| 271 | struct lttng_event_rule *rule = NULL; |
| 272 | struct lttng_kernel_probe_location *location = NULL; |
| 273 | |
| 274 | if (!_event_rule) { |
| 275 | ret = -1; |
| 276 | goto end; |
| 277 | } |
| 278 | |
| 279 | current_buffer_view = lttng_buffer_view_from_view( |
| 280 | &view->buffer, offset, sizeof(*kprobe_comm)); |
| 281 | if (!lttng_buffer_view_is_valid(¤t_buffer_view)) { |
| 282 | ERR("Failed to initialize from malformed event rule kprobe: buffer too short to contain header."); |
| 283 | ret = -1; |
| 284 | goto end; |
| 285 | } |
| 286 | |
| 287 | kprobe_comm = (typeof(kprobe_comm)) current_buffer_view.data; |
| 288 | |
| 289 | /* Skip to payload */ |
| 290 | offset += current_buffer_view.size; |
| 291 | |
| 292 | { |
| 293 | /* Map the name. */ |
| 294 | struct lttng_payload_view current_payload_view = |
| 295 | lttng_payload_view_from_view(view, offset, |
| 296 | kprobe_comm->name_len); |
| 297 | |
| 298 | if (!lttng_payload_view_is_valid(¤t_payload_view)) { |
| 299 | ret = -1; |
| 300 | goto end; |
| 301 | } |
| 302 | |
| 303 | name = current_payload_view.buffer.data; |
| 304 | if (!lttng_buffer_view_contains_string( |
| 305 | ¤t_payload_view.buffer, name, |
| 306 | kprobe_comm->name_len)) { |
| 307 | ret = -1; |
| 308 | goto end; |
| 309 | } |
| 310 | } |
| 311 | |
| 312 | /* Skip after the name. */ |
| 313 | offset += kprobe_comm->name_len; |
| 314 | |
| 315 | /* Map the kernel probe location. */ |
| 316 | { |
| 317 | struct lttng_payload_view current_payload_view = |
| 318 | lttng_payload_view_from_view(view, offset, |
| 319 | kprobe_comm->location_len); |
| 320 | |
| 321 | if (!lttng_payload_view_is_valid(¤t_payload_view)) { |
| 322 | ret = -1; |
| 323 | goto end; |
| 324 | } |
| 325 | |
| 326 | ret = lttng_kernel_probe_location_create_from_payload( |
| 327 | ¤t_payload_view, &location); |
| 328 | if (ret < 0) { |
| 329 | ret = -1; |
| 330 | goto end; |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | if (ret != kprobe_comm->location_len) { |
| 335 | ret = -1; |
| 336 | goto end; |
| 337 | } |
| 338 | |
| 339 | /* Skip after the location */ |
| 340 | offset += kprobe_comm->location_len; |
| 341 | |
| 342 | rule = lttng_event_rule_kernel_kprobe_create(location); |
| 343 | if (!rule) { |
| 344 | ERR("Failed to create event rule kprobe."); |
| 345 | ret = -1; |
| 346 | goto end; |
| 347 | } |
| 348 | |
| 349 | status = lttng_event_rule_kernel_kprobe_set_event_name(rule, name); |
| 350 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { |
| 351 | ERR("Failed to set event rule kprobe name."); |
| 352 | ret = -1; |
| 353 | goto end; |
| 354 | } |
| 355 | |
| 356 | *_event_rule = rule; |
| 357 | rule = NULL; |
| 358 | ret = offset; |
| 359 | end: |
| 360 | lttng_kernel_probe_location_destroy(location); |
| 361 | lttng_event_rule_destroy(rule); |
| 362 | return ret; |
| 363 | } |
| 364 | |
| 365 | enum lttng_event_rule_status lttng_event_rule_kernel_kprobe_get_location( |
| 366 | const struct lttng_event_rule *rule, |
| 367 | const struct lttng_kernel_probe_location **location) |
| 368 | { |
| 369 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; |
| 370 | struct lttng_event_rule_kernel_kprobe *kprobe; |
| 371 | |
| 372 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !location) { |
| 373 | status = LTTNG_EVENT_RULE_STATUS_INVALID; |
| 374 | goto end; |
| 375 | } |
| 376 | |
| 377 | kprobe = container_of(rule, struct lttng_event_rule_kernel_kprobe, parent); |
| 378 | *location = kprobe->location; |
| 379 | |
| 380 | if (!*location) { |
| 381 | status = LTTNG_EVENT_RULE_STATUS_UNSET; |
| 382 | goto end; |
| 383 | } |
| 384 | |
| 385 | end: |
| 386 | return status; |
| 387 | } |
| 388 | |
| 389 | enum lttng_event_rule_status lttng_event_rule_kernel_kprobe_set_event_name( |
| 390 | struct lttng_event_rule *rule, const char *name) |
| 391 | { |
| 392 | char *name_copy = NULL; |
| 393 | struct lttng_event_rule_kernel_kprobe *kprobe; |
| 394 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; |
| 395 | |
| 396 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !name || |
| 397 | strlen(name) == 0) { |
| 398 | status = LTTNG_EVENT_RULE_STATUS_INVALID; |
| 399 | goto end; |
| 400 | } |
| 401 | |
| 402 | kprobe = container_of(rule, struct lttng_event_rule_kernel_kprobe, parent); |
| 403 | name_copy = strdup(name); |
| 404 | if (!name_copy) { |
| 405 | status = LTTNG_EVENT_RULE_STATUS_ERROR; |
| 406 | goto end; |
| 407 | } |
| 408 | |
| 409 | free(kprobe->name); |
| 410 | |
| 411 | kprobe->name = name_copy; |
| 412 | name_copy = NULL; |
| 413 | end: |
| 414 | return status; |
| 415 | } |
| 416 | |
| 417 | enum lttng_event_rule_status lttng_event_rule_kernel_kprobe_get_event_name( |
| 418 | const struct lttng_event_rule *rule, const char **name) |
| 419 | { |
| 420 | struct lttng_event_rule_kernel_kprobe *kprobe; |
| 421 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; |
| 422 | |
| 423 | if (!rule || !IS_KPROBE_EVENT_RULE(rule) || !name) { |
| 424 | status = LTTNG_EVENT_RULE_STATUS_INVALID; |
| 425 | goto end; |
| 426 | } |
| 427 | |
| 428 | kprobe = container_of(rule, struct lttng_event_rule_kernel_kprobe, parent); |
| 429 | if (!kprobe->name) { |
| 430 | status = LTTNG_EVENT_RULE_STATUS_UNSET; |
| 431 | goto end; |
| 432 | } |
| 433 | |
| 434 | *name = kprobe->name; |
| 435 | end: |
| 436 | return status; |
| 437 | } |