| 1 | /* |
| 2 | * SPDX-License-Identifier: LGPL-2.1-only |
| 3 | * |
| 4 | * Copyright 2010-2012 (C) Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * Holds LTTng probes registry. |
| 7 | */ |
| 8 | |
| 9 | #define _LGPL_SOURCE |
| 10 | #include <string.h> |
| 11 | #include <errno.h> |
| 12 | #include <urcu/list.h> |
| 13 | #include <urcu/hlist.h> |
| 14 | #include <lttng/ust-events.h> |
| 15 | #include <lttng/tracepoint.h> |
| 16 | #include "common/tracepoint.h" |
| 17 | #include <assert.h> |
| 18 | #include "common/macros.h" |
| 19 | #include <ctype.h> |
| 20 | |
| 21 | #include "lttng-tracer-core.h" |
| 22 | #include "common/jhash.h" |
| 23 | #include "lib/lttng-ust/events.h" |
| 24 | |
| 25 | /* |
| 26 | * probe list is protected by ust_lock()/ust_unlock(). |
| 27 | */ |
| 28 | static CDS_LIST_HEAD(_probe_list); |
| 29 | |
| 30 | /* |
| 31 | * List of probes registered by not yet processed. |
| 32 | */ |
| 33 | static CDS_LIST_HEAD(lazy_probe_init); |
| 34 | |
| 35 | /* |
| 36 | * lazy_nesting counter ensures we don't trigger lazy probe registration |
| 37 | * fixup while we are performing the fixup. It is protected by the ust |
| 38 | * mutex. |
| 39 | */ |
| 40 | static int lazy_nesting; |
| 41 | |
| 42 | /* |
| 43 | * Validate that each event within the probe provider refers to the |
| 44 | * right probe, and that the resulting name is not too long. |
| 45 | */ |
| 46 | static |
| 47 | bool check_event_provider(const struct lttng_ust_probe_desc *probe_desc) |
| 48 | { |
| 49 | int i; |
| 50 | |
| 51 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 52 | const struct lttng_ust_event_desc *event_desc = probe_desc->event_desc[i]; |
| 53 | |
| 54 | if (event_desc->probe_desc != probe_desc) { |
| 55 | ERR("Error registering probe provider '%s'. Event '%s:%s' refers to the wrong provider descriptor.", |
| 56 | probe_desc->provider_name, probe_desc->provider_name, event_desc->event_name); |
| 57 | return false; /* provider mismatch */ |
| 58 | } |
| 59 | if (!lttng_ust_validate_event_name(event_desc)) { |
| 60 | ERR("Error registering probe provider '%s'. Event '%s:%s' name is too long.", |
| 61 | probe_desc->provider_name, probe_desc->provider_name, event_desc->event_name); |
| 62 | return false; /* provider mismatch */ |
| 63 | } |
| 64 | } |
| 65 | return true; |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * Called under ust lock. |
| 70 | */ |
| 71 | static |
| 72 | void lttng_lazy_probe_register(struct lttng_ust_registered_probe *reg_probe) |
| 73 | { |
| 74 | struct lttng_ust_registered_probe *iter; |
| 75 | struct cds_list_head *probe_list; |
| 76 | |
| 77 | /* |
| 78 | * The provider ensures there are no duplicate event names. |
| 79 | * Duplicated LTTNG_UST_TRACEPOINT_EVENT event names would generate a |
| 80 | * compile-time error due to duplicated symbol names. |
| 81 | */ |
| 82 | |
| 83 | /* |
| 84 | * We sort the providers by struct lttng_ust_probe_desc pointer |
| 85 | * address. |
| 86 | */ |
| 87 | probe_list = &_probe_list; |
| 88 | cds_list_for_each_entry_reverse(iter, probe_list, head) { |
| 89 | BUG_ON(iter == reg_probe); /* Should never be in the list twice */ |
| 90 | if (iter < reg_probe) { |
| 91 | /* We belong to the location right after iter. */ |
| 92 | cds_list_add(®_probe->head, &iter->head); |
| 93 | goto probe_added; |
| 94 | } |
| 95 | } |
| 96 | /* We should be added at the head of the list */ |
| 97 | cds_list_add(®_probe->head, probe_list); |
| 98 | probe_added: |
| 99 | DBG("just registered probe %s containing %u events", |
| 100 | reg_probe->desc->provider_name, reg_probe->desc->nr_events); |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Called under ust lock. |
| 105 | */ |
| 106 | static |
| 107 | void fixup_lazy_probes(void) |
| 108 | { |
| 109 | struct lttng_ust_registered_probe *iter, *tmp; |
| 110 | int ret; |
| 111 | |
| 112 | lazy_nesting++; |
| 113 | cds_list_for_each_entry_safe(iter, tmp, |
| 114 | &lazy_probe_init, lazy_init_head) { |
| 115 | lttng_lazy_probe_register(iter); |
| 116 | iter->lazy = 0; |
| 117 | cds_list_del(&iter->lazy_init_head); |
| 118 | } |
| 119 | ret = lttng_fix_pending_events(); |
| 120 | assert(!ret); |
| 121 | lazy_nesting--; |
| 122 | } |
| 123 | |
| 124 | /* |
| 125 | * Called under ust lock. |
| 126 | */ |
| 127 | struct cds_list_head *lttng_get_probe_list_head(void) |
| 128 | { |
| 129 | if (!lazy_nesting && !cds_list_empty(&lazy_probe_init)) |
| 130 | fixup_lazy_probes(); |
| 131 | return &_probe_list; |
| 132 | } |
| 133 | |
| 134 | static |
| 135 | int check_provider_version(const struct lttng_ust_probe_desc *desc) |
| 136 | { |
| 137 | /* |
| 138 | * Check tracepoint provider version compatibility. |
| 139 | */ |
| 140 | if (desc->major <= LTTNG_UST_PROVIDER_MAJOR && |
| 141 | desc->major >= LTTNG_UST_PROVIDER_MAJOR_OLDEST_COMPATIBLE) { |
| 142 | DBG("Provider \"%s\" accepted, version %u.%u is compatible " |
| 143 | "with LTTng UST provider version %u.%u.", |
| 144 | desc->provider_name, desc->major, desc->minor, |
| 145 | LTTNG_UST_PROVIDER_MAJOR, |
| 146 | LTTNG_UST_PROVIDER_MINOR); |
| 147 | if (desc->major < LTTNG_UST_PROVIDER_MAJOR) { |
| 148 | DBG("However, some LTTng UST features might not be " |
| 149 | "available for this provider unless it is " |
| 150 | "recompiled against a more recent LTTng UST."); |
| 151 | } |
| 152 | return 1; /* accept */ |
| 153 | } else { |
| 154 | ERR("Provider \"%s\" rejected, version %u.%u is incompatible " |
| 155 | "with LTTng UST provider version %u.%u. Please upgrade " |
| 156 | "LTTng UST.", |
| 157 | desc->provider_name, desc->major, desc->minor, |
| 158 | LTTNG_UST_PROVIDER_MAJOR, |
| 159 | LTTNG_UST_PROVIDER_MINOR); |
| 160 | return 0; /* reject */ |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | struct lttng_ust_registered_probe *lttng_ust_probe_register(const struct lttng_ust_probe_desc *desc) |
| 165 | { |
| 166 | struct lttng_ust_registered_probe *reg_probe = NULL; |
| 167 | |
| 168 | lttng_ust_alloc_tls(); |
| 169 | |
| 170 | /* |
| 171 | * If version mismatch, don't register, but don't trigger assert |
| 172 | * on caller. The version check just prints an error. |
| 173 | */ |
| 174 | if (!check_provider_version(desc)) |
| 175 | return NULL; |
| 176 | if (!check_event_provider(desc)) |
| 177 | return NULL; |
| 178 | |
| 179 | ust_lock_nocheck(); |
| 180 | |
| 181 | reg_probe = zmalloc(sizeof(struct lttng_ust_registered_probe)); |
| 182 | if (!reg_probe) |
| 183 | goto end; |
| 184 | reg_probe->desc = desc; |
| 185 | cds_list_add(®_probe->lazy_init_head, &lazy_probe_init); |
| 186 | reg_probe->lazy = 1; |
| 187 | |
| 188 | DBG("adding probe %s containing %u events to lazy registration list", |
| 189 | desc->provider_name, desc->nr_events); |
| 190 | /* |
| 191 | * If there is at least one active session, we need to register |
| 192 | * the probe immediately, since we cannot delay event |
| 193 | * registration because they are needed ASAP. |
| 194 | */ |
| 195 | if (lttng_session_active()) |
| 196 | fixup_lazy_probes(); |
| 197 | |
| 198 | lttng_fix_pending_event_notifiers(); |
| 199 | end: |
| 200 | ust_unlock(); |
| 201 | return reg_probe; |
| 202 | } |
| 203 | |
| 204 | void lttng_ust_probe_unregister(struct lttng_ust_registered_probe *reg_probe) |
| 205 | { |
| 206 | lttng_ust_alloc_tls(); |
| 207 | |
| 208 | if (!reg_probe) |
| 209 | return; |
| 210 | if (!check_provider_version(reg_probe->desc)) |
| 211 | return; |
| 212 | |
| 213 | ust_lock_nocheck(); |
| 214 | if (!reg_probe->lazy) |
| 215 | cds_list_del(®_probe->head); |
| 216 | else |
| 217 | cds_list_del(®_probe->lazy_init_head); |
| 218 | |
| 219 | lttng_probe_provider_unregister_events(reg_probe->desc); |
| 220 | DBG("just unregistered probes of provider %s", reg_probe->desc->provider_name); |
| 221 | ust_unlock(); |
| 222 | free(reg_probe); |
| 223 | } |
| 224 | |
| 225 | void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list) |
| 226 | { |
| 227 | struct tp_list_entry *list_entry, *tmp; |
| 228 | |
| 229 | cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) { |
| 230 | cds_list_del(&list_entry->head); |
| 231 | free(list_entry); |
| 232 | } |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * called with UST lock held. |
| 237 | */ |
| 238 | int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list) |
| 239 | { |
| 240 | struct lttng_ust_registered_probe *reg_probe; |
| 241 | struct cds_list_head *probe_list; |
| 242 | int i; |
| 243 | |
| 244 | probe_list = lttng_get_probe_list_head(); |
| 245 | CDS_INIT_LIST_HEAD(&list->head); |
| 246 | cds_list_for_each_entry(reg_probe, probe_list, head) { |
| 247 | const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc; |
| 248 | |
| 249 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 250 | const struct lttng_ust_event_desc *event_desc = |
| 251 | probe_desc->event_desc[i]; |
| 252 | struct tp_list_entry *list_entry; |
| 253 | |
| 254 | /* Skip event if name is too long. */ |
| 255 | if (!lttng_ust_validate_event_name(event_desc)) |
| 256 | continue; |
| 257 | list_entry = zmalloc(sizeof(*list_entry)); |
| 258 | if (!list_entry) |
| 259 | goto err_nomem; |
| 260 | cds_list_add(&list_entry->head, &list->head); |
| 261 | lttng_ust_format_event_name(event_desc, list_entry->tp.name); |
| 262 | if (!event_desc->loglevel) { |
| 263 | list_entry->tp.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT; |
| 264 | } else { |
| 265 | list_entry->tp.loglevel = *(*event_desc->loglevel); |
| 266 | } |
| 267 | } |
| 268 | } |
| 269 | if (cds_list_empty(&list->head)) |
| 270 | list->iter = NULL; |
| 271 | else |
| 272 | list->iter = |
| 273 | cds_list_first_entry(&list->head, struct tp_list_entry, head); |
| 274 | return 0; |
| 275 | |
| 276 | err_nomem: |
| 277 | lttng_probes_prune_event_list(list); |
| 278 | return -ENOMEM; |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * Return current iteration position, advance internal iterator to next. |
| 283 | * Return NULL if end of list. |
| 284 | */ |
| 285 | struct lttng_ust_abi_tracepoint_iter * |
| 286 | lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list) |
| 287 | { |
| 288 | struct tp_list_entry *entry; |
| 289 | |
| 290 | if (!list->iter) |
| 291 | return NULL; |
| 292 | entry = list->iter; |
| 293 | if (entry->head.next == &list->head) |
| 294 | list->iter = NULL; |
| 295 | else |
| 296 | list->iter = cds_list_entry(entry->head.next, |
| 297 | struct tp_list_entry, head); |
| 298 | return &entry->tp; |
| 299 | } |
| 300 | |
| 301 | void lttng_probes_prune_field_list(struct lttng_ust_field_list *list) |
| 302 | { |
| 303 | struct tp_field_list_entry *list_entry, *tmp; |
| 304 | |
| 305 | cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) { |
| 306 | cds_list_del(&list_entry->head); |
| 307 | free(list_entry); |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | /* |
| 312 | * called with UST lock held. |
| 313 | */ |
| 314 | int lttng_probes_get_field_list(struct lttng_ust_field_list *list) |
| 315 | { |
| 316 | struct lttng_ust_registered_probe *reg_probe; |
| 317 | struct cds_list_head *probe_list; |
| 318 | int i; |
| 319 | |
| 320 | probe_list = lttng_get_probe_list_head(); |
| 321 | CDS_INIT_LIST_HEAD(&list->head); |
| 322 | cds_list_for_each_entry(reg_probe, probe_list, head) { |
| 323 | const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc; |
| 324 | |
| 325 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 326 | const struct lttng_ust_event_desc *event_desc = |
| 327 | probe_desc->event_desc[i]; |
| 328 | int j; |
| 329 | |
| 330 | if (event_desc->tp_class->nr_fields == 0) { |
| 331 | /* Events without fields. */ |
| 332 | struct tp_field_list_entry *list_entry; |
| 333 | |
| 334 | /* Skip event if name is too long. */ |
| 335 | if (!lttng_ust_validate_event_name(event_desc)) |
| 336 | continue; |
| 337 | list_entry = zmalloc(sizeof(*list_entry)); |
| 338 | if (!list_entry) |
| 339 | goto err_nomem; |
| 340 | cds_list_add(&list_entry->head, &list->head); |
| 341 | lttng_ust_format_event_name(event_desc, list_entry->field.event_name); |
| 342 | list_entry->field.field_name[0] = '\0'; |
| 343 | list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER; |
| 344 | if (!event_desc->loglevel) { |
| 345 | list_entry->field.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT; |
| 346 | } else { |
| 347 | list_entry->field.loglevel = *(*event_desc->loglevel); |
| 348 | } |
| 349 | list_entry->field.nowrite = 1; |
| 350 | } |
| 351 | |
| 352 | for (j = 0; j < event_desc->tp_class->nr_fields; j++) { |
| 353 | const struct lttng_ust_event_field *event_field = |
| 354 | event_desc->tp_class->fields[j]; |
| 355 | struct tp_field_list_entry *list_entry; |
| 356 | |
| 357 | /* Skip event if name is too long. */ |
| 358 | if (!lttng_ust_validate_event_name(event_desc)) |
| 359 | continue; |
| 360 | list_entry = zmalloc(sizeof(*list_entry)); |
| 361 | if (!list_entry) |
| 362 | goto err_nomem; |
| 363 | cds_list_add(&list_entry->head, &list->head); |
| 364 | lttng_ust_format_event_name(event_desc, list_entry->field.event_name); |
| 365 | strncpy(list_entry->field.field_name, |
| 366 | event_field->name, |
| 367 | LTTNG_UST_ABI_SYM_NAME_LEN); |
| 368 | list_entry->field.field_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0'; |
| 369 | switch (event_field->type->type) { |
| 370 | case lttng_ust_type_integer: |
| 371 | list_entry->field.type = LTTNG_UST_ABI_FIELD_INTEGER; |
| 372 | break; |
| 373 | case lttng_ust_type_string: |
| 374 | list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING; |
| 375 | break; |
| 376 | case lttng_ust_type_array: |
| 377 | if (lttng_ust_get_type_array(event_field->type)->encoding == lttng_ust_string_encoding_none) |
| 378 | list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER; |
| 379 | else |
| 380 | list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING; |
| 381 | break; |
| 382 | case lttng_ust_type_sequence: |
| 383 | if (lttng_ust_get_type_sequence(event_field->type)->encoding == lttng_ust_string_encoding_none) |
| 384 | list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER; |
| 385 | else |
| 386 | list_entry->field.type = LTTNG_UST_ABI_FIELD_STRING; |
| 387 | break; |
| 388 | case lttng_ust_type_float: |
| 389 | list_entry->field.type = LTTNG_UST_ABI_FIELD_FLOAT; |
| 390 | break; |
| 391 | case lttng_ust_type_enum: |
| 392 | list_entry->field.type = LTTNG_UST_ABI_FIELD_ENUM; |
| 393 | break; |
| 394 | default: |
| 395 | list_entry->field.type = LTTNG_UST_ABI_FIELD_OTHER; |
| 396 | } |
| 397 | if (!event_desc->loglevel) { |
| 398 | list_entry->field.loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT; |
| 399 | } else { |
| 400 | list_entry->field.loglevel = *(*event_desc->loglevel); |
| 401 | } |
| 402 | list_entry->field.nowrite = event_field->nowrite; |
| 403 | } |
| 404 | } |
| 405 | } |
| 406 | if (cds_list_empty(&list->head)) |
| 407 | list->iter = NULL; |
| 408 | else |
| 409 | list->iter = |
| 410 | cds_list_first_entry(&list->head, |
| 411 | struct tp_field_list_entry, head); |
| 412 | return 0; |
| 413 | |
| 414 | err_nomem: |
| 415 | lttng_probes_prune_field_list(list); |
| 416 | return -ENOMEM; |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Return current iteration position, advance internal iterator to next. |
| 421 | * Return NULL if end of list. |
| 422 | */ |
| 423 | struct lttng_ust_abi_field_iter * |
| 424 | lttng_ust_field_list_get_iter_next(struct lttng_ust_field_list *list) |
| 425 | { |
| 426 | struct tp_field_list_entry *entry; |
| 427 | |
| 428 | if (!list->iter) |
| 429 | return NULL; |
| 430 | entry = list->iter; |
| 431 | if (entry->head.next == &list->head) |
| 432 | list->iter = NULL; |
| 433 | else |
| 434 | list->iter = cds_list_entry(entry->head.next, |
| 435 | struct tp_field_list_entry, head); |
| 436 | return &entry->field; |
| 437 | } |