| 1 | /* |
| 2 | * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU Lesser General Public License, version 2.1 only, |
| 6 | * as published by the Free Software Foundation. |
| 7 | * |
| 8 | * This library is distributed in the hope that it will be useful, but WITHOUT |
| 9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License |
| 11 | * for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU Lesser General Public License |
| 14 | * along with this library; if not, write to the Free Software Foundation, |
| 15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 16 | */ |
| 17 | |
| 18 | #include <lttng/notification/notification-internal.h> |
| 19 | #include <lttng/notification/channel-internal.h> |
| 20 | #include <lttng/condition/condition-internal.h> |
| 21 | #include <lttng/endpoint.h> |
| 22 | #include <common/defaults.h> |
| 23 | #include <common/error.h> |
| 24 | #include <common/dynamic-buffer.h> |
| 25 | #include <common/utils.h> |
| 26 | #include <common/defaults.h> |
| 27 | #include <assert.h> |
| 28 | #include "lttng-ctl-helper.h" |
| 29 | |
| 30 | static |
| 31 | int handshake(struct lttng_notification_channel *channel); |
| 32 | |
| 33 | /* |
| 34 | * Populates the reception buffer with the next complete message. |
| 35 | * The caller must acquire the client's lock. |
| 36 | */ |
| 37 | static |
| 38 | int receive_message(struct lttng_notification_channel *channel) |
| 39 | { |
| 40 | ssize_t ret; |
| 41 | struct lttng_notification_channel_message msg; |
| 42 | |
| 43 | ret = lttng_dynamic_buffer_set_size(&channel->reception_buffer, 0); |
| 44 | if (ret) { |
| 45 | goto error; |
| 46 | } |
| 47 | |
| 48 | ret = lttcomm_recv_unix_sock(channel->socket, &msg, sizeof(msg)); |
| 49 | if (ret <= 0) { |
| 50 | ret = -1; |
| 51 | goto error; |
| 52 | } |
| 53 | |
| 54 | if (msg.size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) { |
| 55 | ret = -1; |
| 56 | goto error; |
| 57 | } |
| 58 | |
| 59 | /* Add message header at buffer's start. */ |
| 60 | ret = lttng_dynamic_buffer_append(&channel->reception_buffer, &msg, |
| 61 | sizeof(msg)); |
| 62 | if (ret) { |
| 63 | goto error; |
| 64 | } |
| 65 | |
| 66 | /* Reserve space for the payload. */ |
| 67 | ret = lttng_dynamic_buffer_set_size(&channel->reception_buffer, |
| 68 | channel->reception_buffer.size + msg.size); |
| 69 | if (ret) { |
| 70 | goto error; |
| 71 | } |
| 72 | |
| 73 | /* Receive message payload. */ |
| 74 | ret = lttcomm_recv_unix_sock(channel->socket, |
| 75 | channel->reception_buffer.data + sizeof(msg), msg.size); |
| 76 | if (ret < (ssize_t) msg.size) { |
| 77 | ret = -1; |
| 78 | goto error; |
| 79 | } |
| 80 | ret = 0; |
| 81 | end: |
| 82 | return ret; |
| 83 | error: |
| 84 | if (lttng_dynamic_buffer_set_size(&channel->reception_buffer, 0)) { |
| 85 | ret = -1; |
| 86 | } |
| 87 | goto end; |
| 88 | } |
| 89 | |
| 90 | static |
| 91 | enum lttng_notification_channel_message_type get_current_message_type( |
| 92 | struct lttng_notification_channel *channel) |
| 93 | { |
| 94 | struct lttng_notification_channel_message *msg; |
| 95 | |
| 96 | assert(channel->reception_buffer.size >= sizeof(*msg)); |
| 97 | |
| 98 | msg = (struct lttng_notification_channel_message *) |
| 99 | channel->reception_buffer.data; |
| 100 | return (enum lttng_notification_channel_message_type) msg->type; |
| 101 | } |
| 102 | |
| 103 | static |
| 104 | struct lttng_notification *create_notification_from_current_message( |
| 105 | struct lttng_notification_channel *channel) |
| 106 | { |
| 107 | ssize_t ret; |
| 108 | struct lttng_notification *notification = NULL; |
| 109 | struct lttng_buffer_view view; |
| 110 | |
| 111 | if (channel->reception_buffer.size <= |
| 112 | sizeof(struct lttng_notification_channel_message)) { |
| 113 | goto end; |
| 114 | } |
| 115 | |
| 116 | view = lttng_buffer_view_from_dynamic_buffer(&channel->reception_buffer, |
| 117 | sizeof(struct lttng_notification_channel_message), -1); |
| 118 | |
| 119 | ret = lttng_notification_create_from_buffer(&view, ¬ification); |
| 120 | if (ret != channel->reception_buffer.size - |
| 121 | sizeof(struct lttng_notification_channel_message)) { |
| 122 | lttng_notification_destroy(notification); |
| 123 | notification = NULL; |
| 124 | goto end; |
| 125 | } |
| 126 | end: |
| 127 | return notification; |
| 128 | } |
| 129 | |
| 130 | struct lttng_notification_channel *lttng_notification_channel_create( |
| 131 | struct lttng_endpoint *endpoint) |
| 132 | { |
| 133 | int fd, ret; |
| 134 | bool is_in_tracing_group = false, is_root = false; |
| 135 | char *sock_path = NULL; |
| 136 | struct lttng_notification_channel *channel = NULL; |
| 137 | |
| 138 | if (!endpoint || |
| 139 | endpoint != lttng_session_daemon_notification_endpoint) { |
| 140 | goto end; |
| 141 | } |
| 142 | |
| 143 | sock_path = zmalloc(LTTNG_PATH_MAX); |
| 144 | if (!sock_path) { |
| 145 | goto end; |
| 146 | } |
| 147 | |
| 148 | channel = zmalloc(sizeof(struct lttng_notification_channel)); |
| 149 | if (!channel) { |
| 150 | goto end; |
| 151 | } |
| 152 | channel->socket = -1; |
| 153 | pthread_mutex_init(&channel->lock, NULL); |
| 154 | lttng_dynamic_buffer_init(&channel->reception_buffer); |
| 155 | CDS_INIT_LIST_HEAD(&channel->pending_notifications.list); |
| 156 | |
| 157 | is_root = (getuid() == 0); |
| 158 | if (!is_root) { |
| 159 | is_in_tracing_group = lttng_check_tracing_group(); |
| 160 | } |
| 161 | |
| 162 | if (is_root || is_in_tracing_group) { |
| 163 | lttng_ctl_copy_string(sock_path, |
| 164 | DEFAULT_GLOBAL_NOTIFICATION_CHANNEL_UNIX_SOCK, |
| 165 | LTTNG_PATH_MAX); |
| 166 | ret = lttcomm_connect_unix_sock(sock_path); |
| 167 | if (ret >= 0) { |
| 168 | fd = ret; |
| 169 | goto set_fd; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /* Fallback to local session daemon. */ |
| 174 | ret = snprintf(sock_path, LTTNG_PATH_MAX, |
| 175 | DEFAULT_HOME_NOTIFICATION_CHANNEL_UNIX_SOCK, |
| 176 | utils_get_home_dir()); |
| 177 | if (ret < 0 || ret >= LTTNG_PATH_MAX) { |
| 178 | goto error; |
| 179 | } |
| 180 | |
| 181 | ret = lttcomm_connect_unix_sock(sock_path); |
| 182 | if (ret < 0) { |
| 183 | goto error; |
| 184 | } |
| 185 | fd = ret; |
| 186 | |
| 187 | set_fd: |
| 188 | channel->socket = fd; |
| 189 | |
| 190 | ret = handshake(channel); |
| 191 | if (ret) { |
| 192 | goto error; |
| 193 | } |
| 194 | end: |
| 195 | free(sock_path); |
| 196 | return channel; |
| 197 | error: |
| 198 | lttng_notification_channel_destroy(channel); |
| 199 | channel = NULL; |
| 200 | goto end; |
| 201 | } |
| 202 | |
| 203 | enum lttng_notification_channel_status |
| 204 | lttng_notification_channel_get_next_notification( |
| 205 | struct lttng_notification_channel *channel, |
| 206 | struct lttng_notification **_notification) |
| 207 | { |
| 208 | int ret; |
| 209 | struct lttng_notification *notification = NULL; |
| 210 | enum lttng_notification_channel_status status = |
| 211 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 212 | |
| 213 | if (!channel || !_notification) { |
| 214 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 215 | goto end; |
| 216 | } |
| 217 | |
| 218 | if (channel->pending_notifications.count) { |
| 219 | struct pending_notification *pending_notification; |
| 220 | |
| 221 | assert(!cds_list_empty(&channel->pending_notifications.list)); |
| 222 | |
| 223 | /* Deliver one of the pending notifications. */ |
| 224 | pending_notification = cds_list_first_entry( |
| 225 | &channel->pending_notifications.list, |
| 226 | struct pending_notification, |
| 227 | node); |
| 228 | notification = pending_notification->notification; |
| 229 | if (!notification) { |
| 230 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED; |
| 231 | } |
| 232 | cds_list_del(&pending_notification->node); |
| 233 | channel->pending_notifications.count--; |
| 234 | free(pending_notification); |
| 235 | goto end; |
| 236 | } |
| 237 | |
| 238 | pthread_mutex_lock(&channel->lock); |
| 239 | |
| 240 | ret = receive_message(channel); |
| 241 | if (ret) { |
| 242 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 243 | goto end_unlock; |
| 244 | } |
| 245 | |
| 246 | switch (get_current_message_type(channel)) { |
| 247 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION: |
| 248 | notification = create_notification_from_current_message( |
| 249 | channel); |
| 250 | if (!notification) { |
| 251 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 252 | goto end_unlock; |
| 253 | } |
| 254 | break; |
| 255 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED: |
| 256 | /* No payload to consume. */ |
| 257 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED; |
| 258 | break; |
| 259 | default: |
| 260 | /* Protocol error. */ |
| 261 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 262 | goto end_unlock; |
| 263 | } |
| 264 | |
| 265 | end_unlock: |
| 266 | pthread_mutex_unlock(&channel->lock); |
| 267 | end: |
| 268 | if (_notification) { |
| 269 | *_notification = notification; |
| 270 | } |
| 271 | return status; |
| 272 | } |
| 273 | |
| 274 | static |
| 275 | int enqueue_dropped_notification( |
| 276 | struct lttng_notification_channel *channel) |
| 277 | { |
| 278 | int ret = 0; |
| 279 | struct pending_notification *pending_notification; |
| 280 | struct cds_list_head *last_element = |
| 281 | channel->pending_notifications.list.prev; |
| 282 | |
| 283 | pending_notification = caa_container_of(last_element, |
| 284 | struct pending_notification, node); |
| 285 | if (!pending_notification->notification) { |
| 286 | /* |
| 287 | * The last enqueued notification indicates dropped |
| 288 | * notifications; there is nothing to do as we group |
| 289 | * dropped notifications together. |
| 290 | */ |
| 291 | goto end; |
| 292 | } |
| 293 | |
| 294 | if (channel->pending_notifications.count >= |
| 295 | DEFAULT_CLIENT_MAX_QUEUED_NOTIFICATIONS_COUNT && |
| 296 | pending_notification->notification) { |
| 297 | /* |
| 298 | * Discard the last enqueued notification to indicate |
| 299 | * that notifications were dropped at this point. |
| 300 | */ |
| 301 | lttng_notification_destroy( |
| 302 | pending_notification->notification); |
| 303 | pending_notification->notification = NULL; |
| 304 | goto end; |
| 305 | } |
| 306 | |
| 307 | pending_notification = zmalloc(sizeof(*pending_notification)); |
| 308 | if (!pending_notification) { |
| 309 | ret = -1; |
| 310 | goto end; |
| 311 | } |
| 312 | CDS_INIT_LIST_HEAD(&pending_notification->node); |
| 313 | cds_list_add(&pending_notification->node, |
| 314 | &channel->pending_notifications.list); |
| 315 | channel->pending_notifications.count++; |
| 316 | end: |
| 317 | return ret; |
| 318 | } |
| 319 | |
| 320 | static |
| 321 | int enqueue_notification_from_current_message( |
| 322 | struct lttng_notification_channel *channel) |
| 323 | { |
| 324 | int ret = 0; |
| 325 | struct lttng_notification *notification; |
| 326 | struct pending_notification *pending_notification; |
| 327 | |
| 328 | if (channel->pending_notifications.count >= |
| 329 | DEFAULT_CLIENT_MAX_QUEUED_NOTIFICATIONS_COUNT) { |
| 330 | /* Drop the notification. */ |
| 331 | ret = enqueue_dropped_notification(channel); |
| 332 | goto end; |
| 333 | } |
| 334 | |
| 335 | pending_notification = zmalloc(sizeof(*pending_notification)); |
| 336 | if (!pending_notification) { |
| 337 | ret = -1; |
| 338 | goto error; |
| 339 | } |
| 340 | CDS_INIT_LIST_HEAD(&pending_notification->node); |
| 341 | |
| 342 | notification = create_notification_from_current_message(channel); |
| 343 | if (!notification) { |
| 344 | ret = -1; |
| 345 | goto error; |
| 346 | } |
| 347 | |
| 348 | pending_notification->notification = notification; |
| 349 | cds_list_add(&pending_notification->node, |
| 350 | &channel->pending_notifications.list); |
| 351 | channel->pending_notifications.count++; |
| 352 | end: |
| 353 | return ret; |
| 354 | error: |
| 355 | free(pending_notification); |
| 356 | goto end; |
| 357 | } |
| 358 | |
| 359 | static |
| 360 | int receive_command_reply(struct lttng_notification_channel *channel, |
| 361 | enum lttng_notification_channel_status *status) |
| 362 | { |
| 363 | int ret; |
| 364 | struct lttng_notification_channel_command_reply *reply; |
| 365 | |
| 366 | while (true) { |
| 367 | enum lttng_notification_channel_message_type msg_type; |
| 368 | |
| 369 | ret = receive_message(channel); |
| 370 | if (ret) { |
| 371 | goto end; |
| 372 | } |
| 373 | |
| 374 | msg_type = get_current_message_type(channel); |
| 375 | switch (msg_type) { |
| 376 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY: |
| 377 | goto exit_loop; |
| 378 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION: |
| 379 | ret = enqueue_notification_from_current_message( |
| 380 | channel); |
| 381 | if (ret) { |
| 382 | goto end; |
| 383 | } |
| 384 | break; |
| 385 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED: |
| 386 | ret = enqueue_dropped_notification(channel); |
| 387 | if (ret) { |
| 388 | goto end; |
| 389 | } |
| 390 | break; |
| 391 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE: |
| 392 | { |
| 393 | struct lttng_notification_channel_command_handshake *handshake; |
| 394 | |
| 395 | handshake = (struct lttng_notification_channel_command_handshake *) |
| 396 | (channel->reception_buffer.data + |
| 397 | sizeof(struct lttng_notification_channel_message)); |
| 398 | channel->version.major = handshake->major; |
| 399 | channel->version.minor = handshake->minor; |
| 400 | channel->version.set = true; |
| 401 | break; |
| 402 | } |
| 403 | default: |
| 404 | ret = -1; |
| 405 | goto end; |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | exit_loop: |
| 410 | if (channel->reception_buffer.size < |
| 411 | (sizeof(struct lttng_notification_channel_message) + |
| 412 | sizeof(*reply))) { |
| 413 | /* Invalid message received. */ |
| 414 | ret = -1; |
| 415 | goto end; |
| 416 | } |
| 417 | |
| 418 | reply = (struct lttng_notification_channel_command_reply *) |
| 419 | (channel->reception_buffer.data + |
| 420 | sizeof(struct lttng_notification_channel_message)); |
| 421 | *status = (enum lttng_notification_channel_status) reply->status; |
| 422 | end: |
| 423 | return ret; |
| 424 | } |
| 425 | |
| 426 | static |
| 427 | int handshake(struct lttng_notification_channel *channel) |
| 428 | { |
| 429 | ssize_t ret; |
| 430 | enum lttng_notification_channel_status status = |
| 431 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 432 | struct lttng_notification_channel_command_handshake handshake = { |
| 433 | .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR, |
| 434 | .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR, |
| 435 | }; |
| 436 | struct lttng_notification_channel_message msg_header = { |
| 437 | .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE, |
| 438 | .size = sizeof(handshake), |
| 439 | }; |
| 440 | char send_buffer[sizeof(msg_header) + sizeof(handshake)]; |
| 441 | |
| 442 | memcpy(send_buffer, &msg_header, sizeof(msg_header)); |
| 443 | memcpy(send_buffer + sizeof(msg_header), &handshake, sizeof(handshake)); |
| 444 | |
| 445 | pthread_mutex_lock(&channel->lock); |
| 446 | |
| 447 | ret = lttcomm_send_creds_unix_sock(channel->socket, send_buffer, |
| 448 | sizeof(send_buffer)); |
| 449 | if (ret < 0) { |
| 450 | goto end_unlock; |
| 451 | } |
| 452 | |
| 453 | /* Receive handshake info from the sessiond. */ |
| 454 | ret = receive_command_reply(channel, &status); |
| 455 | if (ret < 0) { |
| 456 | goto end_unlock; |
| 457 | } |
| 458 | |
| 459 | if (!channel->version.set) { |
| 460 | ret = -1; |
| 461 | goto end_unlock; |
| 462 | } |
| 463 | |
| 464 | if (channel->version.major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) { |
| 465 | ret = -1; |
| 466 | goto end_unlock; |
| 467 | } |
| 468 | |
| 469 | end_unlock: |
| 470 | pthread_mutex_unlock(&channel->lock); |
| 471 | return ret; |
| 472 | } |
| 473 | |
| 474 | static |
| 475 | enum lttng_notification_channel_status send_condition_command( |
| 476 | struct lttng_notification_channel *channel, |
| 477 | enum lttng_notification_channel_message_type type, |
| 478 | const struct lttng_condition *condition) |
| 479 | { |
| 480 | int socket; |
| 481 | ssize_t command_size, ret; |
| 482 | enum lttng_notification_channel_status status = |
| 483 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 484 | char *command_buffer = NULL; |
| 485 | struct lttng_notification_channel_message cmd_message = { |
| 486 | .type = type, |
| 487 | }; |
| 488 | |
| 489 | if (!channel) { |
| 490 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 491 | goto end; |
| 492 | } |
| 493 | |
| 494 | assert(type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE || |
| 495 | type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE); |
| 496 | |
| 497 | pthread_mutex_lock(&channel->lock); |
| 498 | socket = channel->socket; |
| 499 | if (!lttng_condition_validate(condition)) { |
| 500 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 501 | goto end_unlock; |
| 502 | } |
| 503 | |
| 504 | ret = lttng_condition_serialize(condition, NULL); |
| 505 | if (ret < 0) { |
| 506 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 507 | goto end_unlock; |
| 508 | } |
| 509 | assert(ret < UINT32_MAX); |
| 510 | cmd_message.size = (uint32_t) ret; |
| 511 | command_size = ret + sizeof( |
| 512 | struct lttng_notification_channel_message); |
| 513 | command_buffer = zmalloc(command_size); |
| 514 | if (!command_buffer) { |
| 515 | goto end_unlock; |
| 516 | } |
| 517 | |
| 518 | memcpy(command_buffer, &cmd_message, sizeof(cmd_message)); |
| 519 | ret = lttng_condition_serialize(condition, |
| 520 | command_buffer + sizeof(cmd_message)); |
| 521 | if (ret < 0) { |
| 522 | goto end_unlock; |
| 523 | } |
| 524 | |
| 525 | ret = lttcomm_send_unix_sock(socket, command_buffer, command_size); |
| 526 | if (ret < 0) { |
| 527 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 528 | goto end_unlock; |
| 529 | } |
| 530 | |
| 531 | ret = receive_command_reply(channel, &status); |
| 532 | if (ret < 0) { |
| 533 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 534 | goto end_unlock; |
| 535 | } |
| 536 | end_unlock: |
| 537 | pthread_mutex_unlock(&channel->lock); |
| 538 | end: |
| 539 | free(command_buffer); |
| 540 | return status; |
| 541 | } |
| 542 | |
| 543 | enum lttng_notification_channel_status lttng_notification_channel_subscribe( |
| 544 | struct lttng_notification_channel *channel, |
| 545 | const struct lttng_condition *condition) |
| 546 | { |
| 547 | return send_condition_command(channel, |
| 548 | LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE, |
| 549 | condition); |
| 550 | } |
| 551 | |
| 552 | enum lttng_notification_channel_status lttng_notification_channel_unsubscribe( |
| 553 | struct lttng_notification_channel *channel, |
| 554 | const struct lttng_condition *condition) |
| 555 | { |
| 556 | return send_condition_command(channel, |
| 557 | LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE, |
| 558 | condition); |
| 559 | } |
| 560 | |
| 561 | void lttng_notification_channel_destroy( |
| 562 | struct lttng_notification_channel *channel) |
| 563 | { |
| 564 | if (!channel) { |
| 565 | return; |
| 566 | } |
| 567 | |
| 568 | if (channel->socket >= 0) { |
| 569 | (void) lttcomm_close_unix_sock(channel->socket); |
| 570 | } |
| 571 | pthread_mutex_destroy(&channel->lock); |
| 572 | lttng_dynamic_buffer_reset(&channel->reception_buffer); |
| 573 | free(channel); |
| 574 | } |