| 1 | /* |
| 2 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> |
| 3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0-only |
| 7 | * |
| 8 | */ |
| 9 | |
| 10 | #include <stddef.h> |
| 11 | #include <stdlib.h> |
| 12 | #include <urcu.h> |
| 13 | #include <common/futex.h> |
| 14 | #include <common/macros.h> |
| 15 | #include <common/utils.h> |
| 16 | #include <sys/stat.h> |
| 17 | |
| 18 | #include "register.h" |
| 19 | #include "lttng-sessiond.h" |
| 20 | #include "testpoint.h" |
| 21 | #include "health-sessiond.h" |
| 22 | #include "fd-limit.h" |
| 23 | #include "shm.h" |
| 24 | #include "utils.h" |
| 25 | #include "thread.h" |
| 26 | |
| 27 | struct thread_state { |
| 28 | struct lttng_pipe *quit_pipe; |
| 29 | struct ust_cmd_queue *ust_cmd_queue; |
| 30 | sem_t ready; |
| 31 | bool running; |
| 32 | int application_socket; |
| 33 | }; |
| 34 | |
| 35 | /* |
| 36 | * Creates the application socket. |
| 37 | */ |
| 38 | static int create_application_socket(void) |
| 39 | { |
| 40 | int ret = 0; |
| 41 | int apps_sock; |
| 42 | const mode_t old_umask = umask(0); |
| 43 | |
| 44 | /* Create the application unix socket */ |
| 45 | apps_sock = lttcomm_create_unix_sock(config.apps_unix_sock_path.value); |
| 46 | if (apps_sock < 0) { |
| 47 | ERR("Create unix sock failed: %s", config.apps_unix_sock_path.value); |
| 48 | ret = -1; |
| 49 | goto end; |
| 50 | } |
| 51 | |
| 52 | /* Set the cloexec flag */ |
| 53 | ret = utils_set_fd_cloexec(apps_sock); |
| 54 | if (ret < 0) { |
| 55 | ERR("Unable to set CLOEXEC flag to the app Unix socket (fd: %d). " |
| 56 | "Continuing but note that the consumer daemon will have a " |
| 57 | "reference to this socket on exec()", apps_sock); |
| 58 | } |
| 59 | |
| 60 | /* File permission MUST be 666 */ |
| 61 | ret = chmod(config.apps_unix_sock_path.value, |
| 62 | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH); |
| 63 | if (ret < 0) { |
| 64 | PERROR("Set file permissions failed on %s", |
| 65 | config.apps_unix_sock_path.value); |
| 66 | goto error_close_socket; |
| 67 | } |
| 68 | |
| 69 | DBG3("Session daemon application socket created (fd = %d) ", apps_sock); |
| 70 | ret = apps_sock; |
| 71 | end: |
| 72 | umask(old_umask); |
| 73 | return ret; |
| 74 | error_close_socket: |
| 75 | if (close(apps_sock)) { |
| 76 | PERROR("Failed to close application socket in error path"); |
| 77 | } |
| 78 | apps_sock = -1; |
| 79 | ret = -1; |
| 80 | goto end; |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * Notify UST applications using the shm mmap futex. |
| 85 | */ |
| 86 | static int notify_ust_apps(int active, bool is_root) |
| 87 | { |
| 88 | char *wait_shm_mmap; |
| 89 | |
| 90 | DBG("Notifying applications of session daemon state: %d", active); |
| 91 | |
| 92 | /* See shm.c for this call implying mmap, shm and futex calls */ |
| 93 | wait_shm_mmap = shm_ust_get_mmap(config.wait_shm_path.value, is_root); |
| 94 | if (wait_shm_mmap == NULL) { |
| 95 | goto error; |
| 96 | } |
| 97 | |
| 98 | /* Wake waiting process */ |
| 99 | futex_wait_update((int32_t *) wait_shm_mmap, active); |
| 100 | |
| 101 | /* Apps notified successfully */ |
| 102 | return 0; |
| 103 | |
| 104 | error: |
| 105 | return -1; |
| 106 | } |
| 107 | |
| 108 | static void cleanup_application_registration_thread(void *data) |
| 109 | { |
| 110 | struct thread_state *thread_state = data; |
| 111 | |
| 112 | if (!data) { |
| 113 | return; |
| 114 | } |
| 115 | |
| 116 | lttng_pipe_destroy(thread_state->quit_pipe); |
| 117 | free(thread_state); |
| 118 | } |
| 119 | |
| 120 | static void set_thread_status(struct thread_state *thread_state, bool running) |
| 121 | { |
| 122 | DBG("Marking application registration thread's state as %s", running ? "running" : "error"); |
| 123 | thread_state->running = running; |
| 124 | sem_post(&thread_state->ready); |
| 125 | } |
| 126 | |
| 127 | static bool wait_thread_status(struct thread_state *thread_state) |
| 128 | { |
| 129 | DBG("Waiting for application registration thread to be ready"); |
| 130 | sem_wait(&thread_state->ready); |
| 131 | if (thread_state->running) { |
| 132 | DBG("Application registration thread is ready"); |
| 133 | } else { |
| 134 | ERR("Initialization of application registration thread failed"); |
| 135 | } |
| 136 | |
| 137 | return thread_state->running; |
| 138 | } |
| 139 | |
| 140 | static void thread_init_cleanup(void *data) |
| 141 | { |
| 142 | struct thread_state *thread_state = data; |
| 143 | |
| 144 | set_thread_status(thread_state, false); |
| 145 | } |
| 146 | |
| 147 | /* |
| 148 | * This thread manage application registration. |
| 149 | */ |
| 150 | static void *thread_application_registration(void *data) |
| 151 | { |
| 152 | int sock = -1, i, ret, pollfd, err = -1; |
| 153 | uint32_t revents, nb_fd; |
| 154 | struct lttng_poll_event events; |
| 155 | /* |
| 156 | * Gets allocated in this thread, enqueued to a global queue, dequeued |
| 157 | * and freed in the manage apps thread. |
| 158 | */ |
| 159 | struct ust_command *ust_cmd = NULL; |
| 160 | const bool is_root = (getuid() == 0); |
| 161 | struct thread_state *thread_state = data; |
| 162 | const int application_socket = thread_state->application_socket; |
| 163 | const int quit_pipe_read_fd = lttng_pipe_get_readfd( |
| 164 | thread_state->quit_pipe); |
| 165 | |
| 166 | DBG("[thread] Manage application registration started"); |
| 167 | |
| 168 | pthread_cleanup_push(thread_init_cleanup, thread_state); |
| 169 | health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG); |
| 170 | |
| 171 | ret = lttcomm_listen_unix_sock(application_socket); |
| 172 | if (ret < 0) { |
| 173 | goto error_listen; |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * Pass 2 as size here for the thread quit pipe and apps_sock. Nothing |
| 178 | * more will be added to this poll set. |
| 179 | */ |
| 180 | ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); |
| 181 | if (ret < 0) { |
| 182 | goto error_create_poll; |
| 183 | } |
| 184 | |
| 185 | /* Add the application registration socket */ |
| 186 | ret = lttng_poll_add(&events, application_socket, LPOLLIN | LPOLLRDHUP); |
| 187 | if (ret < 0) { |
| 188 | goto error_poll_add; |
| 189 | } |
| 190 | |
| 191 | /* Add the application registration socket */ |
| 192 | ret = lttng_poll_add(&events, quit_pipe_read_fd, LPOLLIN | LPOLLRDHUP); |
| 193 | if (ret < 0) { |
| 194 | goto error_poll_add; |
| 195 | } |
| 196 | |
| 197 | set_thread_status(thread_state, true); |
| 198 | pthread_cleanup_pop(0); |
| 199 | |
| 200 | if (testpoint(sessiond_thread_registration_apps)) { |
| 201 | goto error_poll_add; |
| 202 | } |
| 203 | |
| 204 | while (1) { |
| 205 | DBG("Accepting application registration"); |
| 206 | |
| 207 | /* Inifinite blocking call, waiting for transmission */ |
| 208 | restart: |
| 209 | health_poll_entry(); |
| 210 | ret = lttng_poll_wait(&events, -1); |
| 211 | health_poll_exit(); |
| 212 | if (ret < 0) { |
| 213 | /* |
| 214 | * Restart interrupted system call. |
| 215 | */ |
| 216 | if (errno == EINTR) { |
| 217 | goto restart; |
| 218 | } |
| 219 | goto error; |
| 220 | } |
| 221 | |
| 222 | nb_fd = ret; |
| 223 | |
| 224 | for (i = 0; i < nb_fd; i++) { |
| 225 | health_code_update(); |
| 226 | |
| 227 | /* Fetch once the poll data */ |
| 228 | revents = LTTNG_POLL_GETEV(&events, i); |
| 229 | pollfd = LTTNG_POLL_GETFD(&events, i); |
| 230 | |
| 231 | /* Thread quit pipe has been closed. Killing thread. */ |
| 232 | if (pollfd == quit_pipe_read_fd) { |
| 233 | err = 0; |
| 234 | goto exit; |
| 235 | } else { |
| 236 | /* Event on the registration socket */ |
| 237 | if (revents & LPOLLIN) { |
| 238 | sock = lttcomm_accept_unix_sock(application_socket); |
| 239 | if (sock < 0) { |
| 240 | goto error; |
| 241 | } |
| 242 | |
| 243 | /* |
| 244 | * Set socket timeout for both receiving and ending. |
| 245 | * app_socket_timeout is in seconds, whereas |
| 246 | * lttcomm_setsockopt_rcv_timeout and |
| 247 | * lttcomm_setsockopt_snd_timeout expect msec as |
| 248 | * parameter. |
| 249 | */ |
| 250 | if (config.app_socket_timeout >= 0) { |
| 251 | (void) lttcomm_setsockopt_rcv_timeout(sock, |
| 252 | config.app_socket_timeout * 1000); |
| 253 | (void) lttcomm_setsockopt_snd_timeout(sock, |
| 254 | config.app_socket_timeout * 1000); |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * Set the CLOEXEC flag. Return code is useless because |
| 259 | * either way, the show must go on. |
| 260 | */ |
| 261 | (void) utils_set_fd_cloexec(sock); |
| 262 | |
| 263 | /* Create UST registration command for enqueuing */ |
| 264 | ust_cmd = zmalloc(sizeof(struct ust_command)); |
| 265 | if (ust_cmd == NULL) { |
| 266 | PERROR("ust command zmalloc"); |
| 267 | ret = close(sock); |
| 268 | if (ret) { |
| 269 | PERROR("close"); |
| 270 | } |
| 271 | sock = -1; |
| 272 | goto error; |
| 273 | } |
| 274 | |
| 275 | /* |
| 276 | * Using message-based transmissions to ensure we don't |
| 277 | * have to deal with partially received messages. |
| 278 | */ |
| 279 | ret = lttng_fd_get(LTTNG_FD_APPS, 1); |
| 280 | if (ret < 0) { |
| 281 | ERR("Exhausted file descriptors allowed for applications."); |
| 282 | free(ust_cmd); |
| 283 | ret = close(sock); |
| 284 | if (ret) { |
| 285 | PERROR("close"); |
| 286 | } |
| 287 | sock = -1; |
| 288 | continue; |
| 289 | } |
| 290 | |
| 291 | health_code_update(); |
| 292 | ret = ust_app_recv_registration(sock, &ust_cmd->reg_msg); |
| 293 | if (ret < 0) { |
| 294 | free(ust_cmd); |
| 295 | /* Close socket of the application. */ |
| 296 | ret = close(sock); |
| 297 | if (ret) { |
| 298 | PERROR("close"); |
| 299 | } |
| 300 | lttng_fd_put(LTTNG_FD_APPS, 1); |
| 301 | sock = -1; |
| 302 | continue; |
| 303 | } |
| 304 | health_code_update(); |
| 305 | |
| 306 | ust_cmd->sock = sock; |
| 307 | sock = -1; |
| 308 | |
| 309 | DBG("UST registration received with pid:%d ppid:%d uid:%d" |
| 310 | " gid:%d sock:%d name:%s (version %d.%d)", |
| 311 | ust_cmd->reg_msg.pid, ust_cmd->reg_msg.ppid, |
| 312 | ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid, |
| 313 | ust_cmd->sock, ust_cmd->reg_msg.name, |
| 314 | ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor); |
| 315 | |
| 316 | /* |
| 317 | * Lock free enqueue the registration request. The red pill |
| 318 | * has been taken! This apps will be part of the *system*. |
| 319 | */ |
| 320 | cds_wfcq_enqueue(&thread_state->ust_cmd_queue->head, |
| 321 | &thread_state->ust_cmd_queue->tail, |
| 322 | &ust_cmd->node); |
| 323 | |
| 324 | /* |
| 325 | * Wake the registration queue futex. Implicit memory |
| 326 | * barrier with the exchange in cds_wfcq_enqueue. |
| 327 | */ |
| 328 | futex_nto1_wake(&thread_state->ust_cmd_queue->futex); |
| 329 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 330 | ERR("Register apps socket poll error"); |
| 331 | goto error; |
| 332 | } else { |
| 333 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); |
| 334 | goto error; |
| 335 | } |
| 336 | } |
| 337 | } |
| 338 | } |
| 339 | |
| 340 | exit: |
| 341 | error: |
| 342 | /* Notify that the registration thread is gone */ |
| 343 | notify_ust_apps(0, is_root); |
| 344 | |
| 345 | ret = close(application_socket); |
| 346 | if (ret) { |
| 347 | PERROR("Failed to close application registration socket"); |
| 348 | } |
| 349 | if (sock >= 0) { |
| 350 | ret = close(sock); |
| 351 | if (ret) { |
| 352 | PERROR("Failed to close application socket"); |
| 353 | } |
| 354 | lttng_fd_put(LTTNG_FD_APPS, 1); |
| 355 | } |
| 356 | unlink(config.apps_unix_sock_path.value); |
| 357 | |
| 358 | error_poll_add: |
| 359 | lttng_poll_clean(&events); |
| 360 | error_listen: |
| 361 | error_create_poll: |
| 362 | DBG("UST Registration thread cleanup complete"); |
| 363 | if (err) { |
| 364 | health_error(); |
| 365 | ERR("Health error occurred in %s", __func__); |
| 366 | } |
| 367 | health_unregister(health_sessiond); |
| 368 | return NULL; |
| 369 | } |
| 370 | |
| 371 | static bool shutdown_application_registration_thread(void *data) |
| 372 | { |
| 373 | struct thread_state *thread_state = data; |
| 374 | const int write_fd = lttng_pipe_get_writefd(thread_state->quit_pipe); |
| 375 | |
| 376 | return notify_thread_pipe(write_fd) == 1; |
| 377 | } |
| 378 | |
| 379 | struct lttng_thread *launch_application_registration_thread( |
| 380 | struct ust_cmd_queue *cmd_queue) |
| 381 | { |
| 382 | int ret; |
| 383 | struct lttng_pipe *quit_pipe; |
| 384 | struct thread_state *thread_state = NULL; |
| 385 | struct lttng_thread *thread = NULL; |
| 386 | const bool is_root = (getuid() == 0); |
| 387 | int application_socket = -1; |
| 388 | |
| 389 | thread_state = zmalloc(sizeof(*thread_state)); |
| 390 | if (!thread_state) { |
| 391 | goto error_alloc; |
| 392 | } |
| 393 | quit_pipe = lttng_pipe_open(FD_CLOEXEC); |
| 394 | if (!quit_pipe) { |
| 395 | goto error; |
| 396 | } |
| 397 | thread_state->quit_pipe = quit_pipe; |
| 398 | thread_state->ust_cmd_queue = cmd_queue; |
| 399 | application_socket = create_application_socket(); |
| 400 | if (application_socket < 0) { |
| 401 | goto error; |
| 402 | } |
| 403 | thread_state->application_socket = application_socket; |
| 404 | sem_init(&thread_state->ready, 0, 0); |
| 405 | |
| 406 | thread = lttng_thread_create("UST application registration", |
| 407 | thread_application_registration, |
| 408 | shutdown_application_registration_thread, |
| 409 | cleanup_application_registration_thread, |
| 410 | thread_state); |
| 411 | if (!thread) { |
| 412 | goto error; |
| 413 | } |
| 414 | /* |
| 415 | * The application registration thread now owns the application socket |
| 416 | * and the global thread state. The thread state is used to wait for |
| 417 | * the thread's status, but its ownership now belongs to the thread. |
| 418 | */ |
| 419 | application_socket = -1; |
| 420 | if (!wait_thread_status(thread_state)) { |
| 421 | thread_state = NULL; |
| 422 | goto error; |
| 423 | } |
| 424 | |
| 425 | /* Notify all applications to register. */ |
| 426 | ret = notify_ust_apps(1, is_root); |
| 427 | if (ret < 0) { |
| 428 | ERR("Failed to notify applications or create the wait shared memory.\n" |
| 429 | "Execution continues but there might be problems for already\n" |
| 430 | "running applications that wishes to register."); |
| 431 | } |
| 432 | |
| 433 | return thread; |
| 434 | error: |
| 435 | lttng_thread_put(thread); |
| 436 | cleanup_application_registration_thread(thread_state); |
| 437 | if (application_socket >= 0) { |
| 438 | if (close(application_socket)) { |
| 439 | PERROR("Failed to close application registration socket"); |
| 440 | } |
| 441 | } |
| 442 | error_alloc: |
| 443 | return NULL; |
| 444 | } |