| 1 | /* |
| 2 | * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 3 | * |
| 4 | * SPDX-License-Identifier: GPL-2.0-only |
| 5 | * |
| 6 | */ |
| 7 | |
| 8 | #include "field.hpp" |
| 9 | #include "lttng-sessiond.hpp" |
| 10 | #include "notification-thread-commands.hpp" |
| 11 | #include "session.hpp" |
| 12 | #include "trace-class.hpp" |
| 13 | #include "tsdl-trace-class-visitor.hpp" |
| 14 | #include "ust-app.hpp" |
| 15 | #include "ust-field-convert.hpp" |
| 16 | #include "ust-registry.hpp" |
| 17 | |
| 18 | #include <common/compat/directory-handle.hpp> |
| 19 | #include <common/error.hpp> |
| 20 | #include <common/exception.hpp> |
| 21 | #include <common/format.hpp> |
| 22 | #include <common/macros.hpp> |
| 23 | #include <common/make-unique.hpp> |
| 24 | #include <common/pthread-lock.hpp> |
| 25 | #include <common/runas.hpp> |
| 26 | #include <common/time.hpp> |
| 27 | #include <common/urcu.hpp> |
| 28 | |
| 29 | #include <fcntl.h> |
| 30 | #include <functional> |
| 31 | #include <mutex> |
| 32 | #include <sstream> |
| 33 | #include <string> |
| 34 | |
| 35 | namespace ls = lttng::sessiond; |
| 36 | namespace lst = lttng::sessiond::trace; |
| 37 | namespace lsu = lttng::sessiond::ust; |
| 38 | |
| 39 | namespace { |
| 40 | lttng_uuid generate_uuid_or_throw() |
| 41 | { |
| 42 | lttng_uuid new_uuid; |
| 43 | |
| 44 | if (lttng_uuid_generate(new_uuid)) { |
| 45 | LTTNG_THROW_POSIX("Failed to generate UST uuid", errno); |
| 46 | } |
| 47 | |
| 48 | return new_uuid; |
| 49 | } |
| 50 | |
| 51 | int get_count_order(unsigned int count) |
| 52 | { |
| 53 | int order; |
| 54 | |
| 55 | order = lttng_fls(count) - 1; |
| 56 | if (count & (count - 1)) { |
| 57 | order++; |
| 58 | } |
| 59 | |
| 60 | LTTNG_ASSERT(order >= 0); |
| 61 | return order; |
| 62 | } |
| 63 | |
| 64 | void clear_metadata_file(int fd) |
| 65 | { |
| 66 | const auto lseek_ret = lseek(fd, 0, SEEK_SET); |
| 67 | if (lseek_ret < 0) { |
| 68 | LTTNG_THROW_POSIX("Failed to seek to the beginning of the metadata file while clearing it", errno); |
| 69 | } |
| 70 | |
| 71 | const auto ret = ftruncate(fd, 0); |
| 72 | if (ret < 0) { |
| 73 | LTTNG_THROW_POSIX("Failed to truncate the metadata file while clearing it", errno); |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Validate that the id has reached the maximum allowed or not. |
| 79 | */ |
| 80 | bool is_max_channel_id(uint32_t id) |
| 81 | { |
| 82 | return id == UINT32_MAX; |
| 83 | } |
| 84 | |
| 85 | void destroy_channel_rcu(struct rcu_head *head) |
| 86 | { |
| 87 | DIAGNOSTIC_PUSH |
| 88 | DIAGNOSTIC_IGNORE_INVALID_OFFSETOF |
| 89 | lsu::registry_channel *chan = |
| 90 | caa_container_of(head, lsu::registry_channel, _rcu_head); |
| 91 | DIAGNOSTIC_POP |
| 92 | |
| 93 | delete chan; |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | * Destroy every element of the registry and free the memory. This does NOT |
| 98 | * free the registry pointer since it might not have been allocated before so |
| 99 | * it's the caller responsability. |
| 100 | */ |
| 101 | void destroy_channel(lsu::registry_channel *chan, bool notify) |
| 102 | { |
| 103 | struct lttng_ht_iter iter; |
| 104 | lttng::sessiond::ust::registry_event *event; |
| 105 | enum lttng_error_code cmd_ret; |
| 106 | |
| 107 | LTTNG_ASSERT(chan); |
| 108 | |
| 109 | if (notify) { |
| 110 | cmd_ret = notification_thread_command_remove_channel( |
| 111 | the_notification_thread_handle, |
| 112 | chan->_consumer_key, LTTNG_DOMAIN_UST); |
| 113 | if (cmd_ret != LTTNG_OK) { |
| 114 | ERR("Failed to remove channel from notification thread"); |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | if (chan->_events) { |
| 119 | lttng::urcu::read_lock_guard read_lock_guard; |
| 120 | |
| 121 | /* Destroy all event associated with this registry. */ |
| 122 | DIAGNOSTIC_PUSH |
| 123 | DIAGNOSTIC_IGNORE_INVALID_OFFSETOF |
| 124 | cds_lfht_for_each_entry( |
| 125 | chan->_events->ht, &iter.iter, event, _node.node) { |
| 126 | /* Delete the node from the ht and free it. */ |
| 127 | ust_registry_channel_destroy_event(chan, event); |
| 128 | } |
| 129 | DIAGNOSTIC_POP |
| 130 | } |
| 131 | |
| 132 | call_rcu(&chan->_rcu_head, destroy_channel_rcu); |
| 133 | } |
| 134 | } /* namespace */ |
| 135 | |
| 136 | void ls::details::locked_ust_registry_session_release(ust_registry_session *session) |
| 137 | { |
| 138 | pthread_mutex_unlock(&session->_lock); |
| 139 | } |
| 140 | |
| 141 | ust_registry_session::ust_registry_session(const struct lst::abi& in_abi, |
| 142 | uint32_t major, |
| 143 | uint32_t minor, |
| 144 | const char *root_shm_path, |
| 145 | const char *shm_path, |
| 146 | uid_t euid, |
| 147 | gid_t egid, |
| 148 | uint64_t tracing_id) : |
| 149 | lst::trace_class(in_abi, generate_uuid_or_throw()), |
| 150 | _uid{euid}, |
| 151 | _gid{egid}, |
| 152 | _app_tracer_version_major{major}, |
| 153 | _app_tracer_version_minor{minor}, |
| 154 | _tracing_id{tracing_id}, |
| 155 | _metadata_generating_visitor{lttng::make_unique<ls::tsdl::trace_class_visitor>( |
| 156 | abi, [this](const std::string& fragment) { |
| 157 | _append_metadata_fragment(fragment); |
| 158 | })} |
| 159 | { |
| 160 | pthread_mutex_init(&_lock, NULL); |
| 161 | strncpy(_root_shm_path, root_shm_path, sizeof(_root_shm_path)); |
| 162 | _root_shm_path[sizeof(_root_shm_path) - 1] = '\0'; |
| 163 | if (shm_path[0]) { |
| 164 | strncpy(_shm_path, shm_path, sizeof(_shm_path)); |
| 165 | _shm_path[sizeof(_shm_path) - 1] = '\0'; |
| 166 | strncpy(_metadata_path, shm_path, sizeof(_metadata_path)); |
| 167 | _metadata_path[sizeof(_metadata_path) - 1] = '\0'; |
| 168 | strncat(_metadata_path, "/metadata", |
| 169 | sizeof(_metadata_path) - strlen(_metadata_path) - 1); |
| 170 | } |
| 171 | |
| 172 | if (_shm_path[0]) { |
| 173 | if (run_as_mkdir_recursive(_shm_path, S_IRWXU | S_IRWXG, euid, egid)) { |
| 174 | LTTNG_THROW_POSIX("run_as_mkdir_recursive", errno); |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | if (_metadata_path[0]) { |
| 179 | /* Create metadata file. */ |
| 180 | const int ret = run_as_open(_metadata_path, O_WRONLY | O_CREAT | O_EXCL, |
| 181 | S_IRUSR | S_IWUSR, euid, egid); |
| 182 | |
| 183 | if (ret < 0) { |
| 184 | std::stringstream ss; |
| 185 | |
| 186 | ss << "Opening metadata file '" << _metadata_path << "'"; |
| 187 | LTTNG_THROW_POSIX(ss.str(), errno); |
| 188 | } |
| 189 | |
| 190 | _metadata_fd = ret; |
| 191 | } |
| 192 | |
| 193 | _enums.reset(lttng_ht_new(0, LTTNG_HT_TYPE_STRING)); |
| 194 | if (!_enums) { |
| 195 | LTTNG_THROW_POSIX("Failed to create enums hash table", ENOMEM); |
| 196 | } |
| 197 | |
| 198 | /* hash/match functions are specified at call site. */ |
| 199 | _enums->match_fct = NULL; |
| 200 | _enums->hash_fct = NULL; |
| 201 | |
| 202 | _channels.reset(lttng_ht_new(0, LTTNG_HT_TYPE_U64)); |
| 203 | if (!_channels) { |
| 204 | LTTNG_THROW_POSIX("Failed to create channels hash table", ENOMEM); |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | ust_registry_session::~ust_registry_session() |
| 209 | { |
| 210 | int ret; |
| 211 | struct lttng_ht_iter iter; |
| 212 | lsu::registry_channel *chan; |
| 213 | lsu::registry_enum *reg_enum; |
| 214 | |
| 215 | /* On error, EBUSY can be returned if lock. Code flow error. */ |
| 216 | ret = pthread_mutex_destroy(&_lock); |
| 217 | LTTNG_ASSERT(!ret); |
| 218 | |
| 219 | if (_channels) { |
| 220 | lttng::urcu::read_lock_guard read_lock_guard; |
| 221 | |
| 222 | /* Destroy all event associated with this registry. */ |
| 223 | DIAGNOSTIC_PUSH |
| 224 | DIAGNOSTIC_IGNORE_INVALID_OFFSETOF |
| 225 | cds_lfht_for_each_entry(_channels->ht, &iter.iter, chan, _node.node) { |
| 226 | /* Delete the node from the ht and free it. */ |
| 227 | ret = lttng_ht_del(_channels.get(), &iter); |
| 228 | LTTNG_ASSERT(!ret); |
| 229 | destroy_channel(chan, true); |
| 230 | } |
| 231 | DIAGNOSTIC_POP |
| 232 | } |
| 233 | |
| 234 | free(_metadata); |
| 235 | if (_metadata_fd >= 0) { |
| 236 | ret = close(_metadata_fd); |
| 237 | if (ret) { |
| 238 | PERROR("close"); |
| 239 | } |
| 240 | |
| 241 | ret = run_as_unlink(_metadata_path, _uid, _gid); |
| 242 | if (ret) { |
| 243 | PERROR("unlink"); |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | if (_root_shm_path[0]) { |
| 248 | /* Try to delete the directory hierarchy. */ |
| 249 | (void) run_as_rmdir_recursive(_root_shm_path, _uid, _gid, |
| 250 | LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG); |
| 251 | } |
| 252 | |
| 253 | /* Destroy the enum hash table */ |
| 254 | if (_enums) { |
| 255 | rcu_read_lock(); |
| 256 | /* Destroy all enum entries associated with this registry. */ |
| 257 | DIAGNOSTIC_PUSH |
| 258 | DIAGNOSTIC_IGNORE_INVALID_OFFSETOF |
| 259 | cds_lfht_for_each_entry (_enums->ht, &iter.iter, reg_enum, node.node) { |
| 260 | ust_registry_destroy_enum(this, reg_enum); |
| 261 | } |
| 262 | DIAGNOSTIC_POP |
| 263 | |
| 264 | rcu_read_unlock(); |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | ust_registry_session::locked_ptr ust_registry_session::lock() |
| 269 | { |
| 270 | pthread_mutex_lock(&_lock); |
| 271 | return locked_ptr(this); |
| 272 | } |
| 273 | |
| 274 | /* |
| 275 | * Initialize registry with default values. |
| 276 | */ |
| 277 | void ust_registry_session::add_channel(uint64_t key) |
| 278 | { |
| 279 | lttng::pthread::lock_guard session_lock_guard(_lock); |
| 280 | |
| 281 | /* |
| 282 | * Assign a channel ID right now since the event notification comes |
| 283 | * *before* the channel notify so the ID needs to be set at this point so |
| 284 | * the metadata can be dumped for that event. |
| 285 | */ |
| 286 | if (is_max_channel_id(_used_channel_id)) { |
| 287 | LTTNG_THROW_ERROR(fmt::format("Failed to allocate unique id for channel under session while adding channel")); |
| 288 | } |
| 289 | |
| 290 | auto chan = new lsu::registry_channel( |
| 291 | _get_next_channel_id(), |
| 292 | /* Registered channel listener. */ |
| 293 | [this](const lsu::registry_channel& registered_channel) { |
| 294 | /* |
| 295 | * Channel registration completed, serialize it's layout's |
| 296 | * description. |
| 297 | */ |
| 298 | registered_channel.accept(*_metadata_generating_visitor); |
| 299 | }, |
| 300 | /* Added event listener. */ |
| 301 | [this](const lsu::registry_channel& channel, |
| 302 | const lsu::registry_event& added_event) { |
| 303 | /* |
| 304 | * The channel and its event classes will be dumped at once when |
| 305 | * it is registered. This check prevents event classes from being |
| 306 | * declared before their stream class. |
| 307 | */ |
| 308 | if (channel.is_registered()) { |
| 309 | added_event.accept(*_metadata_generating_visitor); |
| 310 | } |
| 311 | }); |
| 312 | |
| 313 | lttng::urcu::read_lock_guard rcu_read_lock_guard; |
| 314 | lttng_ht_node_init_u64(&chan->_node, key); |
| 315 | lttng_ht_add_unique_u64(_channels.get(), &chan->_node); |
| 316 | } |
| 317 | |
| 318 | lttng::sessiond::ust::registry_channel& ust_registry_session::get_channel( |
| 319 | uint64_t channel_key) const |
| 320 | { |
| 321 | lttng::urcu::read_lock_guard read_lock_guard; |
| 322 | struct lttng_ht_node_u64 *node; |
| 323 | struct lttng_ht_iter iter; |
| 324 | |
| 325 | ASSERT_LOCKED(_lock); |
| 326 | |
| 327 | lttng_ht_lookup(_channels.get(), &channel_key, &iter); |
| 328 | node = lttng_ht_iter_get_node_u64(&iter); |
| 329 | if (!node) { |
| 330 | LTTNG_THROW_INVALID_ARGUMENT_ERROR(fmt::format( |
| 331 | "Invalid channel key provided: channel key = {}", channel_key)); |
| 332 | } |
| 333 | |
| 334 | DIAGNOSTIC_PUSH |
| 335 | DIAGNOSTIC_IGNORE_INVALID_OFFSETOF |
| 336 | auto chan = caa_container_of(node, lsu::registry_channel, _node); |
| 337 | DIAGNOSTIC_POP |
| 338 | return *chan; |
| 339 | } |
| 340 | |
| 341 | void ust_registry_session::remove_channel(uint64_t channel_key, bool notify) |
| 342 | { |
| 343 | struct lttng_ht_iter iter; |
| 344 | int ret; |
| 345 | lttng::urcu::read_lock_guard read_lock_guard; |
| 346 | |
| 347 | ASSERT_LOCKED(_lock); |
| 348 | auto& channel = get_channel(channel_key); |
| 349 | |
| 350 | iter.iter.node = &channel._node.node; |
| 351 | ret = lttng_ht_del(_channels.get(), &iter); |
| 352 | LTTNG_ASSERT(!ret); |
| 353 | destroy_channel(&channel, notify); |
| 354 | } |
| 355 | |
| 356 | void ust_registry_session::_visit_environment( |
| 357 | lttng::sessiond::trace::trace_class_visitor& visitor) const |
| 358 | { |
| 359 | ASSERT_LOCKED(_lock); |
| 360 | |
| 361 | visitor.visit(lst::environment_field<const char *>("domain", "ust")); |
| 362 | visitor.visit(lst::environment_field<const char *>("tracer_name", "lttng-ust")); |
| 363 | visitor.visit(lst::environment_field<int64_t>("tracer_major", _app_tracer_version_major)); |
| 364 | visitor.visit(lst::environment_field<int64_t>("tracer_minor", _app_tracer_version_minor)); |
| 365 | visitor.visit(lst::environment_field<const char *>("tracer_buffering_scheme", |
| 366 | get_buffering_scheme() == LTTNG_BUFFER_PER_PID ? "pid" : "uid")); |
| 367 | visitor.visit(lst::environment_field<int64_t>("architecture_bit_width", abi.bits_per_long)); |
| 368 | |
| 369 | { |
| 370 | /* The caller already holds the session and session list locks. */ |
| 371 | ASSERT_SESSION_LIST_LOCKED(); |
| 372 | const auto session = lttng::sessiond::find_session_by_id(_tracing_id); |
| 373 | |
| 374 | LTTNG_ASSERT(session); |
| 375 | ASSERT_LOCKED(session->lock); |
| 376 | |
| 377 | visitor.visit(lst::environment_field<const char *>("trace_name", |
| 378 | session->has_auto_generated_name ? DEFAULT_SESSION_NAME : |
| 379 | session->name)); |
| 380 | visitor.visit(lst::environment_field<std::string>("trace_creation_datetime", |
| 381 | lttng::utils::time_to_iso8601_str(session->creation_time))); |
| 382 | visitor.visit(lst::environment_field<const char *>("hostname", session->hostname)); |
| 383 | } |
| 384 | } |
| 385 | |
| 386 | void ust_registry_session::_accept_on_clock_classes(lst::trace_class_visitor& visitor) const |
| 387 | { |
| 388 | ASSERT_LOCKED(_lock); |
| 389 | _clock.accept(visitor); |
| 390 | } |
| 391 | |
| 392 | void ust_registry_session::_accept_on_stream_classes(lst::trace_class_visitor& visitor) const |
| 393 | { |
| 394 | ASSERT_LOCKED(_lock); |
| 395 | |
| 396 | std::vector<const lttng::sessiond::ust::registry_channel *> sorted_stream_classes; |
| 397 | |
| 398 | { |
| 399 | lttng::urcu::read_lock_guard rcu_lock_guard; |
| 400 | const lsu::registry_channel *channel; |
| 401 | lttng_ht_iter channel_it; |
| 402 | |
| 403 | DIAGNOSTIC_PUSH |
| 404 | DIAGNOSTIC_IGNORE_INVALID_OFFSETOF |
| 405 | cds_lfht_for_each_entry(_channels->ht, &channel_it.iter, channel, _node.node) { |
| 406 | sorted_stream_classes.emplace_back(channel); |
| 407 | } |
| 408 | DIAGNOSTIC_POP |
| 409 | } |
| 410 | |
| 411 | std::sort(sorted_stream_classes.begin(), sorted_stream_classes.end(), |
| 412 | [](const lttng::sessiond::ust::registry_channel *a, |
| 413 | const lttng::sessiond::ust::registry_channel *b) { |
| 414 | return a->id < b->id; |
| 415 | }); |
| 416 | |
| 417 | for (const auto stream_class : sorted_stream_classes) { |
| 418 | stream_class->accept(visitor); |
| 419 | } |
| 420 | } |
| 421 | |
| 422 | /* |
| 423 | * Return next available channel id and increment the used counter. The |
| 424 | * is_max_channel_id function MUST be called before in order to validate |
| 425 | * if the maximum number of IDs have been reached. If not, it is safe to call |
| 426 | * this function. |
| 427 | * |
| 428 | * Return a unique channel ID. If max is reached, the used_channel_id counter |
| 429 | * is returned. |
| 430 | */ |
| 431 | uint32_t ust_registry_session::_get_next_channel_id() |
| 432 | { |
| 433 | if (is_max_channel_id(_used_channel_id)) { |
| 434 | return _used_channel_id; |
| 435 | } |
| 436 | |
| 437 | _used_channel_id++; |
| 438 | return _next_channel_id++; |
| 439 | } |
| 440 | |
| 441 | void ust_registry_session::_increase_metadata_size(size_t reservation_length) |
| 442 | { |
| 443 | const auto new_len = _metadata_len + reservation_length; |
| 444 | auto new_alloc_len = new_len; |
| 445 | const auto old_alloc_len = _metadata_alloc_len; |
| 446 | |
| 447 | /* Rounding the new allocation length to the next power of 2 would overflow. */ |
| 448 | if (new_alloc_len > (UINT32_MAX >> 1)) { |
| 449 | LTTNG_THROW_ERROR("Failed to reserve trace metadata storage as the new size would overflow"); |
| 450 | } |
| 451 | |
| 452 | /* The current allocation length is already the largest we can afford. */ |
| 453 | if ((old_alloc_len << 1) > (UINT32_MAX >> 1)) { |
| 454 | LTTNG_THROW_ERROR("Failed to reserve trace metadata storage as the max size was already reached"); |
| 455 | } |
| 456 | |
| 457 | if (new_alloc_len > old_alloc_len) { |
| 458 | new_alloc_len = std::max<size_t>( |
| 459 | 1U << get_count_order(new_alloc_len), old_alloc_len << 1); |
| 460 | |
| 461 | auto newptr = (char *) realloc(_metadata, new_alloc_len); |
| 462 | if (!newptr) { |
| 463 | LTTNG_THROW_POSIX("Failed to allocate trace metadata storage", errno); |
| 464 | } |
| 465 | |
| 466 | _metadata = newptr; |
| 467 | |
| 468 | /* We zero directly the memory from start of allocation. */ |
| 469 | memset(&_metadata[old_alloc_len], 0, new_alloc_len - old_alloc_len); |
| 470 | _metadata_alloc_len = new_alloc_len; |
| 471 | } |
| 472 | |
| 473 | _metadata_len += reservation_length; |
| 474 | } |
| 475 | |
| 476 | void ust_registry_session::_append_metadata_fragment(const std::string& fragment) |
| 477 | { |
| 478 | const auto offset = _metadata_len; |
| 479 | |
| 480 | _increase_metadata_size(fragment.size()); |
| 481 | memcpy(&_metadata[offset], fragment.c_str(), fragment.size()); |
| 482 | |
| 483 | if (_metadata_fd >= 0) { |
| 484 | const auto bytes_written = |
| 485 | lttng_write(_metadata_fd, fragment.c_str(), fragment.size()); |
| 486 | |
| 487 | if (bytes_written != fragment.size()) { |
| 488 | LTTNG_THROW_POSIX("Failed to write trace metadata fragment to file", |
| 489 | errno); |
| 490 | } |
| 491 | } |
| 492 | } |
| 493 | |
| 494 | void ust_registry_session::_reset_metadata() |
| 495 | { |
| 496 | _metadata_len_sent = 0; |
| 497 | memset(_metadata, 0, _metadata_alloc_len); |
| 498 | _metadata_len = 0; |
| 499 | |
| 500 | if (_metadata_fd > 0) { |
| 501 | /* Clear the metadata file's content. */ |
| 502 | clear_metadata_file(_metadata_fd); |
| 503 | } |
| 504 | } |
| 505 | |
| 506 | void ust_registry_session::_generate_metadata() |
| 507 | { |
| 508 | accept(*_metadata_generating_visitor); |
| 509 | } |
| 510 | |
| 511 | void ust_registry_session::regenerate_metadata() |
| 512 | { |
| 513 | lttng::pthread::lock_guard registry_lock(_lock); |
| 514 | |
| 515 | _metadata_version++; |
| 516 | _reset_metadata(); |
| 517 | _generate_metadata(); |
| 518 | } |