| 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 | #include <common/compat/poll.h> |
| 30 | |
| 31 | static |
| 32 | int handshake(struct lttng_notification_channel *channel); |
| 33 | |
| 34 | /* |
| 35 | * Populates the reception buffer with the next complete message. |
| 36 | * The caller must acquire the channel's lock. |
| 37 | */ |
| 38 | static |
| 39 | int receive_message(struct lttng_notification_channel *channel) |
| 40 | { |
| 41 | ssize_t ret; |
| 42 | struct lttng_notification_channel_message msg; |
| 43 | |
| 44 | if (lttng_dynamic_buffer_set_size(&channel->reception_buffer, 0)) { |
| 45 | ret = -1; |
| 46 | goto end; |
| 47 | } |
| 48 | |
| 49 | ret = lttcomm_recv_unix_sock(channel->socket, &msg, sizeof(msg)); |
| 50 | if (ret <= 0) { |
| 51 | ret = -1; |
| 52 | goto error; |
| 53 | } |
| 54 | |
| 55 | if (msg.size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) { |
| 56 | ret = -1; |
| 57 | goto error; |
| 58 | } |
| 59 | |
| 60 | /* Add message header at buffer's start. */ |
| 61 | ret = lttng_dynamic_buffer_append(&channel->reception_buffer, &msg, |
| 62 | sizeof(msg)); |
| 63 | if (ret) { |
| 64 | goto error; |
| 65 | } |
| 66 | |
| 67 | /* Reserve space for the payload. */ |
| 68 | ret = lttng_dynamic_buffer_set_size(&channel->reception_buffer, |
| 69 | channel->reception_buffer.size + msg.size); |
| 70 | if (ret) { |
| 71 | goto error; |
| 72 | } |
| 73 | |
| 74 | /* Receive message payload. */ |
| 75 | ret = lttcomm_recv_unix_sock(channel->socket, |
| 76 | channel->reception_buffer.data + sizeof(msg), msg.size); |
| 77 | if (ret < (ssize_t) msg.size) { |
| 78 | ret = -1; |
| 79 | goto error; |
| 80 | } |
| 81 | ret = 0; |
| 82 | end: |
| 83 | return ret; |
| 84 | error: |
| 85 | if (lttng_dynamic_buffer_set_size(&channel->reception_buffer, 0)) { |
| 86 | ret = -1; |
| 87 | } |
| 88 | goto end; |
| 89 | } |
| 90 | |
| 91 | static |
| 92 | enum lttng_notification_channel_message_type get_current_message_type( |
| 93 | struct lttng_notification_channel *channel) |
| 94 | { |
| 95 | struct lttng_notification_channel_message *msg; |
| 96 | |
| 97 | assert(channel->reception_buffer.size >= sizeof(*msg)); |
| 98 | |
| 99 | msg = (struct lttng_notification_channel_message *) |
| 100 | channel->reception_buffer.data; |
| 101 | return (enum lttng_notification_channel_message_type) msg->type; |
| 102 | } |
| 103 | |
| 104 | static |
| 105 | struct lttng_notification *create_notification_from_current_message( |
| 106 | struct lttng_notification_channel *channel) |
| 107 | { |
| 108 | ssize_t ret; |
| 109 | struct lttng_notification *notification = NULL; |
| 110 | struct lttng_buffer_view view; |
| 111 | |
| 112 | if (channel->reception_buffer.size <= |
| 113 | sizeof(struct lttng_notification_channel_message)) { |
| 114 | goto end; |
| 115 | } |
| 116 | |
| 117 | view = lttng_buffer_view_from_dynamic_buffer(&channel->reception_buffer, |
| 118 | sizeof(struct lttng_notification_channel_message), -1); |
| 119 | |
| 120 | ret = lttng_notification_create_from_buffer(&view, ¬ification); |
| 121 | if (ret != channel->reception_buffer.size - |
| 122 | sizeof(struct lttng_notification_channel_message)) { |
| 123 | lttng_notification_destroy(notification); |
| 124 | notification = NULL; |
| 125 | goto end; |
| 126 | } |
| 127 | end: |
| 128 | return notification; |
| 129 | } |
| 130 | |
| 131 | struct lttng_notification_channel *lttng_notification_channel_create( |
| 132 | struct lttng_endpoint *endpoint) |
| 133 | { |
| 134 | int fd, ret; |
| 135 | bool is_in_tracing_group = false, is_root = false; |
| 136 | char *sock_path = NULL; |
| 137 | struct lttng_notification_channel *channel = NULL; |
| 138 | |
| 139 | if (!endpoint || |
| 140 | endpoint != lttng_session_daemon_notification_endpoint) { |
| 141 | goto end; |
| 142 | } |
| 143 | |
| 144 | sock_path = zmalloc(LTTNG_PATH_MAX); |
| 145 | if (!sock_path) { |
| 146 | goto end; |
| 147 | } |
| 148 | |
| 149 | channel = zmalloc(sizeof(struct lttng_notification_channel)); |
| 150 | if (!channel) { |
| 151 | goto end; |
| 152 | } |
| 153 | channel->socket = -1; |
| 154 | pthread_mutex_init(&channel->lock, NULL); |
| 155 | lttng_dynamic_buffer_init(&channel->reception_buffer); |
| 156 | CDS_INIT_LIST_HEAD(&channel->pending_notifications.list); |
| 157 | |
| 158 | is_root = (getuid() == 0); |
| 159 | if (!is_root) { |
| 160 | is_in_tracing_group = lttng_check_tracing_group(); |
| 161 | } |
| 162 | |
| 163 | if (is_root || is_in_tracing_group) { |
| 164 | lttng_ctl_copy_string(sock_path, |
| 165 | DEFAULT_GLOBAL_NOTIFICATION_CHANNEL_UNIX_SOCK, |
| 166 | LTTNG_PATH_MAX); |
| 167 | ret = lttcomm_connect_unix_sock(sock_path); |
| 168 | if (ret >= 0) { |
| 169 | fd = ret; |
| 170 | goto set_fd; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | /* Fallback to local session daemon. */ |
| 175 | ret = snprintf(sock_path, LTTNG_PATH_MAX, |
| 176 | DEFAULT_HOME_NOTIFICATION_CHANNEL_UNIX_SOCK, |
| 177 | utils_get_home_dir()); |
| 178 | if (ret < 0 || ret >= LTTNG_PATH_MAX) { |
| 179 | goto error; |
| 180 | } |
| 181 | |
| 182 | ret = lttcomm_connect_unix_sock(sock_path); |
| 183 | if (ret < 0) { |
| 184 | goto error; |
| 185 | } |
| 186 | fd = ret; |
| 187 | |
| 188 | set_fd: |
| 189 | channel->socket = fd; |
| 190 | |
| 191 | ret = handshake(channel); |
| 192 | if (ret) { |
| 193 | goto error; |
| 194 | } |
| 195 | end: |
| 196 | free(sock_path); |
| 197 | return channel; |
| 198 | error: |
| 199 | lttng_notification_channel_destroy(channel); |
| 200 | channel = NULL; |
| 201 | goto end; |
| 202 | } |
| 203 | |
| 204 | enum lttng_notification_channel_status |
| 205 | lttng_notification_channel_get_next_notification( |
| 206 | struct lttng_notification_channel *channel, |
| 207 | struct lttng_notification **_notification) |
| 208 | { |
| 209 | int ret; |
| 210 | struct lttng_notification *notification = NULL; |
| 211 | enum lttng_notification_channel_status status = |
| 212 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 213 | struct lttng_poll_event events; |
| 214 | |
| 215 | if (!channel || !_notification) { |
| 216 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 217 | goto end; |
| 218 | } |
| 219 | |
| 220 | pthread_mutex_lock(&channel->lock); |
| 221 | |
| 222 | if (channel->pending_notifications.count) { |
| 223 | struct pending_notification *pending_notification; |
| 224 | |
| 225 | assert(!cds_list_empty(&channel->pending_notifications.list)); |
| 226 | |
| 227 | /* Deliver one of the pending notifications. */ |
| 228 | pending_notification = cds_list_first_entry( |
| 229 | &channel->pending_notifications.list, |
| 230 | struct pending_notification, |
| 231 | node); |
| 232 | notification = pending_notification->notification; |
| 233 | if (!notification) { |
| 234 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED; |
| 235 | } |
| 236 | cds_list_del(&pending_notification->node); |
| 237 | channel->pending_notifications.count--; |
| 238 | free(pending_notification); |
| 239 | goto end_unlock; |
| 240 | } |
| 241 | |
| 242 | /* |
| 243 | * Block on interruptible epoll/poll() instead of the message reception |
| 244 | * itself as the recvmsg() wrappers always restart on EINTR. We choose |
| 245 | * to wait using interruptible epoll/poll() in order to: |
| 246 | * 1) Return if a signal occurs, |
| 247 | * 2) Not deal with partially received messages. |
| 248 | * |
| 249 | * The drawback to this approach is that we assume that messages |
| 250 | * are complete/well formed. If a message is shorter than its |
| 251 | * announced length, receive_message() will block on recvmsg() |
| 252 | * and never return (even if a signal is received). |
| 253 | */ |
| 254 | ret = lttng_poll_create(&events, 1, LTTNG_CLOEXEC); |
| 255 | if (ret < 0) { |
| 256 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 257 | goto end_unlock; |
| 258 | } |
| 259 | ret = lttng_poll_add(&events, channel->socket, LPOLLIN | LPOLLERR); |
| 260 | if (ret < 0) { |
| 261 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 262 | goto end_clean_poll; |
| 263 | } |
| 264 | ret = lttng_poll_wait_interruptible(&events, -1); |
| 265 | if (ret <= 0) { |
| 266 | status = (ret == -1 && errno == EINTR) ? |
| 267 | LTTNG_NOTIFICATION_CHANNEL_STATUS_INTERRUPTED : |
| 268 | LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 269 | goto end_clean_poll; |
| 270 | } |
| 271 | |
| 272 | ret = receive_message(channel); |
| 273 | if (ret) { |
| 274 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 275 | goto end_clean_poll; |
| 276 | } |
| 277 | |
| 278 | switch (get_current_message_type(channel)) { |
| 279 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION: |
| 280 | notification = create_notification_from_current_message( |
| 281 | channel); |
| 282 | if (!notification) { |
| 283 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 284 | goto end_clean_poll; |
| 285 | } |
| 286 | break; |
| 287 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED: |
| 288 | /* No payload to consume. */ |
| 289 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED; |
| 290 | break; |
| 291 | default: |
| 292 | /* Protocol error. */ |
| 293 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 294 | goto end_clean_poll; |
| 295 | } |
| 296 | |
| 297 | end_clean_poll: |
| 298 | lttng_poll_clean(&events); |
| 299 | end_unlock: |
| 300 | pthread_mutex_unlock(&channel->lock); |
| 301 | *_notification = notification; |
| 302 | end: |
| 303 | return status; |
| 304 | } |
| 305 | |
| 306 | static |
| 307 | int enqueue_dropped_notification( |
| 308 | struct lttng_notification_channel *channel) |
| 309 | { |
| 310 | int ret = 0; |
| 311 | struct pending_notification *pending_notification; |
| 312 | struct cds_list_head *last_element = |
| 313 | channel->pending_notifications.list.prev; |
| 314 | |
| 315 | pending_notification = caa_container_of(last_element, |
| 316 | struct pending_notification, node); |
| 317 | if (!pending_notification->notification) { |
| 318 | /* |
| 319 | * The last enqueued notification indicates dropped |
| 320 | * notifications; there is nothing to do as we group |
| 321 | * dropped notifications together. |
| 322 | */ |
| 323 | goto end; |
| 324 | } |
| 325 | |
| 326 | if (channel->pending_notifications.count >= |
| 327 | DEFAULT_CLIENT_MAX_QUEUED_NOTIFICATIONS_COUNT && |
| 328 | pending_notification->notification) { |
| 329 | /* |
| 330 | * Discard the last enqueued notification to indicate |
| 331 | * that notifications were dropped at this point. |
| 332 | */ |
| 333 | lttng_notification_destroy( |
| 334 | pending_notification->notification); |
| 335 | pending_notification->notification = NULL; |
| 336 | goto end; |
| 337 | } |
| 338 | |
| 339 | pending_notification = zmalloc(sizeof(*pending_notification)); |
| 340 | if (!pending_notification) { |
| 341 | ret = -1; |
| 342 | goto end; |
| 343 | } |
| 344 | CDS_INIT_LIST_HEAD(&pending_notification->node); |
| 345 | cds_list_add(&pending_notification->node, |
| 346 | &channel->pending_notifications.list); |
| 347 | channel->pending_notifications.count++; |
| 348 | end: |
| 349 | return ret; |
| 350 | } |
| 351 | |
| 352 | static |
| 353 | int enqueue_notification_from_current_message( |
| 354 | struct lttng_notification_channel *channel) |
| 355 | { |
| 356 | int ret = 0; |
| 357 | struct lttng_notification *notification; |
| 358 | struct pending_notification *pending_notification; |
| 359 | |
| 360 | if (channel->pending_notifications.count >= |
| 361 | DEFAULT_CLIENT_MAX_QUEUED_NOTIFICATIONS_COUNT) { |
| 362 | /* Drop the notification. */ |
| 363 | ret = enqueue_dropped_notification(channel); |
| 364 | goto end; |
| 365 | } |
| 366 | |
| 367 | pending_notification = zmalloc(sizeof(*pending_notification)); |
| 368 | if (!pending_notification) { |
| 369 | ret = -1; |
| 370 | goto error; |
| 371 | } |
| 372 | CDS_INIT_LIST_HEAD(&pending_notification->node); |
| 373 | |
| 374 | notification = create_notification_from_current_message(channel); |
| 375 | if (!notification) { |
| 376 | ret = -1; |
| 377 | goto error; |
| 378 | } |
| 379 | |
| 380 | pending_notification->notification = notification; |
| 381 | cds_list_add(&pending_notification->node, |
| 382 | &channel->pending_notifications.list); |
| 383 | channel->pending_notifications.count++; |
| 384 | end: |
| 385 | return ret; |
| 386 | error: |
| 387 | free(pending_notification); |
| 388 | goto end; |
| 389 | } |
| 390 | |
| 391 | enum lttng_notification_channel_status |
| 392 | lttng_notification_channel_has_pending_notification( |
| 393 | struct lttng_notification_channel *channel, |
| 394 | bool *_notification_pending) |
| 395 | { |
| 396 | int ret; |
| 397 | enum lttng_notification_channel_status status = |
| 398 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 399 | struct lttng_poll_event events; |
| 400 | |
| 401 | if (!channel || !_notification_pending) { |
| 402 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 403 | goto end; |
| 404 | } |
| 405 | |
| 406 | pthread_mutex_lock(&channel->lock); |
| 407 | |
| 408 | if (channel->pending_notifications.count) { |
| 409 | *_notification_pending = true; |
| 410 | goto end_unlock; |
| 411 | } |
| 412 | |
| 413 | if (channel->socket < 0) { |
| 414 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_CLOSED; |
| 415 | goto end_unlock; |
| 416 | } |
| 417 | |
| 418 | /* |
| 419 | * Check, without blocking, if data is available on the channel's |
| 420 | * socket. If there is data available, it is safe to read (blocking) |
| 421 | * on the socket for a message from the session daemon. |
| 422 | * |
| 423 | * Since all commands wait for the session daemon's reply before |
| 424 | * releasing the channel's lock, the protocol only allows for |
| 425 | * notifications and "notification dropped" messages to come |
| 426 | * through. If we receive a different message type, it is |
| 427 | * considered a protocol error. |
| 428 | * |
| 429 | * Note that this function is not guaranteed not to block. This |
| 430 | * will block until our peer (the session daemon) has sent a complete |
| 431 | * message if we see data available on the socket. If the peer does |
| 432 | * not respect the protocol, this may block indefinitely. |
| 433 | */ |
| 434 | ret = lttng_poll_create(&events, 1, LTTNG_CLOEXEC); |
| 435 | if (ret < 0) { |
| 436 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 437 | goto end_unlock; |
| 438 | } |
| 439 | ret = lttng_poll_add(&events, channel->socket, LPOLLIN | LPOLLERR); |
| 440 | if (ret < 0) { |
| 441 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 442 | goto end_clean_poll; |
| 443 | } |
| 444 | /* timeout = 0: return immediately. */ |
| 445 | ret = lttng_poll_wait_interruptible(&events, 0); |
| 446 | if (ret == 0) { |
| 447 | /* No data available. */ |
| 448 | *_notification_pending = false; |
| 449 | goto end_clean_poll; |
| 450 | } else if (ret < 0) { |
| 451 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 452 | goto end_clean_poll; |
| 453 | } |
| 454 | |
| 455 | /* Data available on socket. */ |
| 456 | ret = receive_message(channel); |
| 457 | if (ret) { |
| 458 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 459 | goto end_clean_poll; |
| 460 | } |
| 461 | |
| 462 | switch (get_current_message_type(channel)) { |
| 463 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION: |
| 464 | ret = enqueue_notification_from_current_message(channel); |
| 465 | if (ret) { |
| 466 | goto end_clean_poll; |
| 467 | } |
| 468 | *_notification_pending = true; |
| 469 | break; |
| 470 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED: |
| 471 | ret = enqueue_dropped_notification(channel); |
| 472 | if (ret) { |
| 473 | goto end_clean_poll; |
| 474 | } |
| 475 | *_notification_pending = true; |
| 476 | break; |
| 477 | default: |
| 478 | /* Protocol error. */ |
| 479 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 480 | goto end_clean_poll; |
| 481 | } |
| 482 | |
| 483 | end_clean_poll: |
| 484 | lttng_poll_clean(&events); |
| 485 | end_unlock: |
| 486 | pthread_mutex_unlock(&channel->lock); |
| 487 | end: |
| 488 | return status; |
| 489 | } |
| 490 | |
| 491 | static |
| 492 | int receive_command_reply(struct lttng_notification_channel *channel, |
| 493 | enum lttng_notification_channel_status *status) |
| 494 | { |
| 495 | int ret; |
| 496 | struct lttng_notification_channel_command_reply *reply; |
| 497 | |
| 498 | while (true) { |
| 499 | enum lttng_notification_channel_message_type msg_type; |
| 500 | |
| 501 | ret = receive_message(channel); |
| 502 | if (ret) { |
| 503 | goto end; |
| 504 | } |
| 505 | |
| 506 | msg_type = get_current_message_type(channel); |
| 507 | switch (msg_type) { |
| 508 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY: |
| 509 | goto exit_loop; |
| 510 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION: |
| 511 | ret = enqueue_notification_from_current_message( |
| 512 | channel); |
| 513 | if (ret) { |
| 514 | goto end; |
| 515 | } |
| 516 | break; |
| 517 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED: |
| 518 | ret = enqueue_dropped_notification(channel); |
| 519 | if (ret) { |
| 520 | goto end; |
| 521 | } |
| 522 | break; |
| 523 | case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE: |
| 524 | { |
| 525 | struct lttng_notification_channel_command_handshake *handshake; |
| 526 | |
| 527 | handshake = (struct lttng_notification_channel_command_handshake *) |
| 528 | (channel->reception_buffer.data + |
| 529 | sizeof(struct lttng_notification_channel_message)); |
| 530 | channel->version.major = handshake->major; |
| 531 | channel->version.minor = handshake->minor; |
| 532 | channel->version.set = true; |
| 533 | break; |
| 534 | } |
| 535 | default: |
| 536 | ret = -1; |
| 537 | goto end; |
| 538 | } |
| 539 | } |
| 540 | |
| 541 | exit_loop: |
| 542 | if (channel->reception_buffer.size < |
| 543 | (sizeof(struct lttng_notification_channel_message) + |
| 544 | sizeof(*reply))) { |
| 545 | /* Invalid message received. */ |
| 546 | ret = -1; |
| 547 | goto end; |
| 548 | } |
| 549 | |
| 550 | reply = (struct lttng_notification_channel_command_reply *) |
| 551 | (channel->reception_buffer.data + |
| 552 | sizeof(struct lttng_notification_channel_message)); |
| 553 | *status = (enum lttng_notification_channel_status) reply->status; |
| 554 | end: |
| 555 | return ret; |
| 556 | } |
| 557 | |
| 558 | static |
| 559 | int handshake(struct lttng_notification_channel *channel) |
| 560 | { |
| 561 | ssize_t ret; |
| 562 | enum lttng_notification_channel_status status = |
| 563 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 564 | struct lttng_notification_channel_command_handshake handshake = { |
| 565 | .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR, |
| 566 | .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR, |
| 567 | }; |
| 568 | struct lttng_notification_channel_message msg_header = { |
| 569 | .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE, |
| 570 | .size = sizeof(handshake), |
| 571 | }; |
| 572 | char send_buffer[sizeof(msg_header) + sizeof(handshake)]; |
| 573 | |
| 574 | memcpy(send_buffer, &msg_header, sizeof(msg_header)); |
| 575 | memcpy(send_buffer + sizeof(msg_header), &handshake, sizeof(handshake)); |
| 576 | |
| 577 | pthread_mutex_lock(&channel->lock); |
| 578 | |
| 579 | ret = lttcomm_send_creds_unix_sock(channel->socket, send_buffer, |
| 580 | sizeof(send_buffer)); |
| 581 | if (ret < 0) { |
| 582 | goto end_unlock; |
| 583 | } |
| 584 | |
| 585 | /* Receive handshake info from the sessiond. */ |
| 586 | ret = receive_command_reply(channel, &status); |
| 587 | if (ret < 0) { |
| 588 | goto end_unlock; |
| 589 | } |
| 590 | |
| 591 | if (!channel->version.set) { |
| 592 | ret = -1; |
| 593 | goto end_unlock; |
| 594 | } |
| 595 | |
| 596 | if (channel->version.major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) { |
| 597 | ret = -1; |
| 598 | goto end_unlock; |
| 599 | } |
| 600 | |
| 601 | end_unlock: |
| 602 | pthread_mutex_unlock(&channel->lock); |
| 603 | return ret; |
| 604 | } |
| 605 | |
| 606 | static |
| 607 | enum lttng_notification_channel_status send_condition_command( |
| 608 | struct lttng_notification_channel *channel, |
| 609 | enum lttng_notification_channel_message_type type, |
| 610 | const struct lttng_condition *condition) |
| 611 | { |
| 612 | int socket; |
| 613 | ssize_t ret; |
| 614 | enum lttng_notification_channel_status status = |
| 615 | LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; |
| 616 | struct lttng_dynamic_buffer buffer; |
| 617 | struct lttng_notification_channel_message cmd_header = { |
| 618 | .type = (int8_t) type, |
| 619 | }; |
| 620 | |
| 621 | lttng_dynamic_buffer_init(&buffer); |
| 622 | |
| 623 | if (!channel) { |
| 624 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 625 | goto end; |
| 626 | } |
| 627 | |
| 628 | assert(type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE || |
| 629 | type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE); |
| 630 | |
| 631 | pthread_mutex_lock(&channel->lock); |
| 632 | socket = channel->socket; |
| 633 | if (!lttng_condition_validate(condition)) { |
| 634 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 635 | goto end_unlock; |
| 636 | } |
| 637 | |
| 638 | ret = lttng_dynamic_buffer_append(&buffer, &cmd_header, |
| 639 | sizeof(cmd_header)); |
| 640 | if (ret) { |
| 641 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 642 | goto end_unlock; |
| 643 | } |
| 644 | |
| 645 | ret = lttng_condition_serialize(condition, &buffer); |
| 646 | if (ret) { |
| 647 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID; |
| 648 | goto end_unlock; |
| 649 | } |
| 650 | |
| 651 | /* Update payload length. */ |
| 652 | ((struct lttng_notification_channel_message *) buffer.data)->size = |
| 653 | (uint32_t) (buffer.size - sizeof(cmd_header)); |
| 654 | |
| 655 | ret = lttcomm_send_unix_sock(socket, buffer.data, buffer.size); |
| 656 | if (ret < 0) { |
| 657 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 658 | goto end_unlock; |
| 659 | } |
| 660 | |
| 661 | ret = receive_command_reply(channel, &status); |
| 662 | if (ret < 0) { |
| 663 | status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR; |
| 664 | goto end_unlock; |
| 665 | } |
| 666 | end_unlock: |
| 667 | pthread_mutex_unlock(&channel->lock); |
| 668 | end: |
| 669 | lttng_dynamic_buffer_reset(&buffer); |
| 670 | return status; |
| 671 | } |
| 672 | |
| 673 | enum lttng_notification_channel_status lttng_notification_channel_subscribe( |
| 674 | struct lttng_notification_channel *channel, |
| 675 | const struct lttng_condition *condition) |
| 676 | { |
| 677 | return send_condition_command(channel, |
| 678 | LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE, |
| 679 | condition); |
| 680 | } |
| 681 | |
| 682 | enum lttng_notification_channel_status lttng_notification_channel_unsubscribe( |
| 683 | struct lttng_notification_channel *channel, |
| 684 | const struct lttng_condition *condition) |
| 685 | { |
| 686 | return send_condition_command(channel, |
| 687 | LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE, |
| 688 | condition); |
| 689 | } |
| 690 | |
| 691 | void lttng_notification_channel_destroy( |
| 692 | struct lttng_notification_channel *channel) |
| 693 | { |
| 694 | if (!channel) { |
| 695 | return; |
| 696 | } |
| 697 | |
| 698 | if (channel->socket >= 0) { |
| 699 | (void) lttcomm_close_unix_sock(channel->socket); |
| 700 | } |
| 701 | pthread_mutex_destroy(&channel->lock); |
| 702 | lttng_dynamic_buffer_reset(&channel->reception_buffer); |
| 703 | free(channel); |
| 704 | } |