| 1 | /* |
| 2 | * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU General Public License, version 2 only, as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program 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 General Public License for |
| 11 | * more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License along with |
| 14 | * this program; if not, write to the Free Software Foundation, Inc., 51 |
| 15 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 16 | */ |
| 17 | |
| 18 | #define _LGPL_SOURCE |
| 19 | #include <assert.h> |
| 20 | |
| 21 | #include <common/common.h> |
| 22 | #include <common/sessiond-comm/sessiond-comm.h> |
| 23 | #include <common/uri.h> |
| 24 | #include <common/utils.h> |
| 25 | |
| 26 | #include <common/compat/endian.h> |
| 27 | |
| 28 | #include "fd-limit.h" |
| 29 | #include "agent-thread.h" |
| 30 | #include "agent.h" |
| 31 | #include "lttng-sessiond.h" |
| 32 | #include "session.h" |
| 33 | #include "utils.h" |
| 34 | |
| 35 | static int agent_tracing_enabled = -1; |
| 36 | |
| 37 | /* |
| 38 | * Note that there is not port here. It's set after this URI is parsed so we |
| 39 | * can let the user define a custom one. However, localhost is ALWAYS the |
| 40 | * default listening address. |
| 41 | */ |
| 42 | static const char *default_reg_uri = |
| 43 | "tcp://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS; |
| 44 | |
| 45 | /* |
| 46 | * Update agent application using the given socket. This is done just after |
| 47 | * registration was successful. |
| 48 | * |
| 49 | * This is a quite heavy call in terms of locking since the session list lock |
| 50 | * AND session lock are acquired. |
| 51 | */ |
| 52 | static void update_agent_app(struct agent_app *app) |
| 53 | { |
| 54 | struct ltt_session *session, *stmp; |
| 55 | struct ltt_session_list *list; |
| 56 | |
| 57 | list = session_get_list(); |
| 58 | assert(list); |
| 59 | |
| 60 | session_lock_list(); |
| 61 | cds_list_for_each_entry_safe(session, stmp, &list->head, list) { |
| 62 | session_lock(session); |
| 63 | if (session->ust_session) { |
| 64 | struct agent *agt; |
| 65 | |
| 66 | rcu_read_lock(); |
| 67 | agt = trace_ust_find_agent(session->ust_session, app->domain); |
| 68 | if (agt) { |
| 69 | agent_update(agt, app->sock->fd); |
| 70 | } |
| 71 | rcu_read_unlock(); |
| 72 | } |
| 73 | session_unlock(session); |
| 74 | } |
| 75 | session_unlock_list(); |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * Create and init socket from uri. |
| 80 | */ |
| 81 | static struct lttcomm_sock *init_tcp_socket(void) |
| 82 | { |
| 83 | int ret; |
| 84 | struct lttng_uri *uri = NULL; |
| 85 | struct lttcomm_sock *sock = NULL; |
| 86 | unsigned int port; |
| 87 | bool bind_succeeded = false; |
| 88 | |
| 89 | /* |
| 90 | * This should never fail since the URI is hardcoded and the port is set |
| 91 | * before this thread is launched. |
| 92 | */ |
| 93 | ret = uri_parse(default_reg_uri, &uri); |
| 94 | assert(ret); |
| 95 | assert(config.agent_tcp_port.begin > 0); |
| 96 | uri->port = config.agent_tcp_port.begin; |
| 97 | |
| 98 | sock = lttcomm_alloc_sock_from_uri(uri); |
| 99 | uri_free(uri); |
| 100 | if (sock == NULL) { |
| 101 | ERR("[agent-thread] agent allocating TCP socket"); |
| 102 | goto error; |
| 103 | } |
| 104 | |
| 105 | ret = lttcomm_create_sock(sock); |
| 106 | if (ret < 0) { |
| 107 | goto error; |
| 108 | } |
| 109 | |
| 110 | for (port = config.agent_tcp_port.begin; |
| 111 | port <= config.agent_tcp_port.end; port++) { |
| 112 | ret = lttcomm_sock_set_port(sock, (uint16_t) port); |
| 113 | if (ret) { |
| 114 | ERR("[agent-thread] Failed to set port %u on socket", |
| 115 | port); |
| 116 | goto error; |
| 117 | } |
| 118 | DBG3("[agent-thread] Trying to bind on port %u", port); |
| 119 | ret = sock->ops->bind(sock); |
| 120 | if (!ret) { |
| 121 | bind_succeeded = true; |
| 122 | break; |
| 123 | } |
| 124 | |
| 125 | if (errno == EADDRINUSE) { |
| 126 | DBG("Failed to bind to port %u since it is already in use", |
| 127 | port); |
| 128 | } else { |
| 129 | PERROR("Failed to bind to port %u", port); |
| 130 | goto error; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | if (!bind_succeeded) { |
| 135 | if (config.agent_tcp_port.begin == config.agent_tcp_port.end) { |
| 136 | WARN("Another process is already using the agent port %i. " |
| 137 | "Agent support will be deactivated.", |
| 138 | config.agent_tcp_port.begin); |
| 139 | goto error; |
| 140 | } else { |
| 141 | WARN("All ports in the range [%i, %i] are already in use. " |
| 142 | "Agent support will be deactivated.", |
| 143 | config.agent_tcp_port.begin, |
| 144 | config.agent_tcp_port.end); |
| 145 | goto error; |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | ret = sock->ops->listen(sock, -1); |
| 150 | if (ret < 0) { |
| 151 | goto error; |
| 152 | } |
| 153 | |
| 154 | DBG("[agent-thread] Listening on TCP port %u and socket %d", |
| 155 | port, sock->fd); |
| 156 | |
| 157 | return sock; |
| 158 | |
| 159 | error: |
| 160 | if (sock) { |
| 161 | lttcomm_destroy_sock(sock); |
| 162 | } |
| 163 | return NULL; |
| 164 | } |
| 165 | |
| 166 | /* |
| 167 | * Close and destroy the given TCP socket. |
| 168 | */ |
| 169 | static void destroy_tcp_socket(struct lttcomm_sock *sock) |
| 170 | { |
| 171 | int ret; |
| 172 | uint16_t port; |
| 173 | |
| 174 | assert(sock); |
| 175 | |
| 176 | ret = lttcomm_sock_get_port(sock, &port); |
| 177 | if (ret) { |
| 178 | ERR("[agent-thread] Failed to get port of agent TCP socket"); |
| 179 | port = 0; |
| 180 | } |
| 181 | |
| 182 | DBG3("[agent-thread] Destroy TCP socket on port %" PRIu16, |
| 183 | port); |
| 184 | |
| 185 | /* This will return gracefully if fd is invalid. */ |
| 186 | sock->ops->close(sock); |
| 187 | lttcomm_destroy_sock(sock); |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * Handle a new agent registration using the reg socket. After that, a new |
| 192 | * agent application is added to the global hash table and attach to an UST app |
| 193 | * object. If r_app is not NULL, the created app is set to the pointer. |
| 194 | * |
| 195 | * Return the new FD created upon accept() on success or else a negative errno |
| 196 | * value. |
| 197 | */ |
| 198 | static int handle_registration(struct lttcomm_sock *reg_sock, |
| 199 | struct agent_app **r_app) |
| 200 | { |
| 201 | int ret; |
| 202 | pid_t pid; |
| 203 | uint32_t major_version, minor_version; |
| 204 | ssize_t size; |
| 205 | enum lttng_domain_type domain; |
| 206 | struct agent_app *app; |
| 207 | struct agent_register_msg msg; |
| 208 | struct lttcomm_sock *new_sock; |
| 209 | |
| 210 | assert(reg_sock); |
| 211 | |
| 212 | new_sock = reg_sock->ops->accept(reg_sock); |
| 213 | if (!new_sock) { |
| 214 | ret = -ENOTCONN; |
| 215 | goto error; |
| 216 | } |
| 217 | |
| 218 | size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0); |
| 219 | if (size < sizeof(msg)) { |
| 220 | ret = -EINVAL; |
| 221 | goto error_socket; |
| 222 | } |
| 223 | domain = be32toh(msg.domain); |
| 224 | pid = be32toh(msg.pid); |
| 225 | major_version = be32toh(msg.major_version); |
| 226 | minor_version = be32toh(msg.minor_version); |
| 227 | |
| 228 | /* Test communication protocol version of the registring agent. */ |
| 229 | if (major_version != AGENT_MAJOR_VERSION) { |
| 230 | ret = -EINVAL; |
| 231 | goto error_socket; |
| 232 | } |
| 233 | if (minor_version != AGENT_MINOR_VERSION) { |
| 234 | ret = -EINVAL; |
| 235 | goto error_socket; |
| 236 | } |
| 237 | |
| 238 | DBG2("[agent-thread] New registration for pid %d domain %d on socket %d", |
| 239 | pid, domain, new_sock->fd); |
| 240 | |
| 241 | app = agent_create_app(pid, domain, new_sock); |
| 242 | if (!app) { |
| 243 | ret = -ENOMEM; |
| 244 | goto error_socket; |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * Add before assigning the socket value to the UST app so it can be found |
| 249 | * concurrently. |
| 250 | */ |
| 251 | agent_add_app(app); |
| 252 | |
| 253 | /* |
| 254 | * We don't need to attach the agent app to the app. If we ever do so, we |
| 255 | * should consider both registration order of agent before app and app |
| 256 | * before agent. |
| 257 | */ |
| 258 | |
| 259 | if (r_app) { |
| 260 | *r_app = app; |
| 261 | } |
| 262 | |
| 263 | return new_sock->fd; |
| 264 | |
| 265 | error_socket: |
| 266 | new_sock->ops->close(new_sock); |
| 267 | lttcomm_destroy_sock(new_sock); |
| 268 | error: |
| 269 | return ret; |
| 270 | } |
| 271 | |
| 272 | bool agent_tracing_is_enabled(void) |
| 273 | { |
| 274 | int enabled; |
| 275 | |
| 276 | enabled = uatomic_read(&agent_tracing_enabled); |
| 277 | assert(enabled != -1); |
| 278 | return enabled == 1; |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * Write agent TCP port using the rundir. |
| 283 | */ |
| 284 | static int write_agent_port(uint16_t port) |
| 285 | { |
| 286 | return utils_create_pid_file((pid_t) port, |
| 287 | config.agent_port_file_path.value); |
| 288 | } |
| 289 | |
| 290 | /* |
| 291 | * This thread manage application notify communication. |
| 292 | */ |
| 293 | void *agent_thread_manage_registration(void *data) |
| 294 | { |
| 295 | int i, ret, pollfd; |
| 296 | uint32_t revents, nb_fd; |
| 297 | struct lttng_poll_event events; |
| 298 | struct lttcomm_sock *reg_sock; |
| 299 | |
| 300 | DBG("[agent-thread] Manage agent application registration."); |
| 301 | |
| 302 | rcu_register_thread(); |
| 303 | rcu_thread_online(); |
| 304 | |
| 305 | /* Agent initialization call MUST be called before starting the thread. */ |
| 306 | assert(agent_apps_ht_by_sock); |
| 307 | |
| 308 | /* Create pollset with size 2, quit pipe and socket. */ |
| 309 | ret = sessiond_set_thread_pollset(&events, 2); |
| 310 | if (ret < 0) { |
| 311 | goto error_poll_create; |
| 312 | } |
| 313 | |
| 314 | reg_sock = init_tcp_socket(); |
| 315 | if (reg_sock) { |
| 316 | uint16_t port; |
| 317 | |
| 318 | assert(lttcomm_sock_get_port(reg_sock, &port) == 0); |
| 319 | |
| 320 | ret = write_agent_port(port); |
| 321 | if (ret) { |
| 322 | ERR("[agent-thread] Failed to create agent port file: agent tracing will be unavailable"); |
| 323 | /* Don't prevent the launch of the sessiond on error. */ |
| 324 | sessiond_notify_ready(); |
| 325 | goto error; |
| 326 | } |
| 327 | } else { |
| 328 | /* Don't prevent the launch of the sessiond on error. */ |
| 329 | sessiond_notify_ready(); |
| 330 | goto error_tcp_socket; |
| 331 | } |
| 332 | |
| 333 | /* |
| 334 | * Signal that the agent thread is ready. The command thread |
| 335 | * may start to query whether or not agent tracing is enabled. |
| 336 | */ |
| 337 | uatomic_set(&agent_tracing_enabled, 1); |
| 338 | sessiond_notify_ready(); |
| 339 | |
| 340 | /* Add TCP socket to poll set. */ |
| 341 | ret = lttng_poll_add(&events, reg_sock->fd, |
| 342 | LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP); |
| 343 | if (ret < 0) { |
| 344 | goto error; |
| 345 | } |
| 346 | |
| 347 | while (1) { |
| 348 | DBG3("[agent-thread] Manage agent polling"); |
| 349 | |
| 350 | /* Inifinite blocking call, waiting for transmission */ |
| 351 | restart: |
| 352 | ret = lttng_poll_wait(&events, -1); |
| 353 | DBG3("[agent-thread] Manage agent return from poll on %d fds", |
| 354 | LTTNG_POLL_GETNB(&events)); |
| 355 | if (ret < 0) { |
| 356 | /* |
| 357 | * Restart interrupted system call. |
| 358 | */ |
| 359 | if (errno == EINTR) { |
| 360 | goto restart; |
| 361 | } |
| 362 | goto error; |
| 363 | } |
| 364 | nb_fd = ret; |
| 365 | DBG3("[agent-thread] %d fd ready", nb_fd); |
| 366 | |
| 367 | for (i = 0; i < nb_fd; i++) { |
| 368 | /* Fetch once the poll data */ |
| 369 | revents = LTTNG_POLL_GETEV(&events, i); |
| 370 | pollfd = LTTNG_POLL_GETFD(&events, i); |
| 371 | |
| 372 | if (!revents) { |
| 373 | /* No activity for this FD (poll implementation). */ |
| 374 | continue; |
| 375 | } |
| 376 | |
| 377 | /* Thread quit pipe has been closed. Killing thread. */ |
| 378 | ret = sessiond_check_thread_quit_pipe(pollfd, revents); |
| 379 | if (ret) { |
| 380 | goto exit; |
| 381 | } |
| 382 | |
| 383 | if (revents & LPOLLIN) { |
| 384 | int new_fd; |
| 385 | struct agent_app *app = NULL; |
| 386 | |
| 387 | assert(pollfd == reg_sock->fd); |
| 388 | new_fd = handle_registration(reg_sock, &app); |
| 389 | if (new_fd < 0) { |
| 390 | continue; |
| 391 | } |
| 392 | /* Should not have a NULL app on success. */ |
| 393 | assert(app); |
| 394 | |
| 395 | /* |
| 396 | * Since this is a command socket (write then read), |
| 397 | * only add poll error event to only detect shutdown. |
| 398 | */ |
| 399 | ret = lttng_poll_add(&events, new_fd, |
| 400 | LPOLLERR | LPOLLHUP | LPOLLRDHUP); |
| 401 | if (ret < 0) { |
| 402 | agent_destroy_app_by_sock(new_fd); |
| 403 | continue; |
| 404 | } |
| 405 | |
| 406 | /* Update newly registered app. */ |
| 407 | update_agent_app(app); |
| 408 | |
| 409 | /* On failure, the poll will detect it and clean it up. */ |
| 410 | ret = agent_send_registration_done(app); |
| 411 | if (ret < 0) { |
| 412 | /* Removing from the poll set */ |
| 413 | ret = lttng_poll_del(&events, new_fd); |
| 414 | if (ret < 0) { |
| 415 | goto error; |
| 416 | } |
| 417 | agent_destroy_app_by_sock(new_fd); |
| 418 | continue; |
| 419 | } |
| 420 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 421 | /* Removing from the poll set */ |
| 422 | ret = lttng_poll_del(&events, pollfd); |
| 423 | if (ret < 0) { |
| 424 | goto error; |
| 425 | } |
| 426 | agent_destroy_app_by_sock(pollfd); |
| 427 | } else { |
| 428 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); |
| 429 | goto error; |
| 430 | } |
| 431 | } |
| 432 | } |
| 433 | |
| 434 | exit: |
| 435 | /* Whatever happens, try to delete it and exit. */ |
| 436 | (void) lttng_poll_del(&events, reg_sock->fd); |
| 437 | error: |
| 438 | destroy_tcp_socket(reg_sock); |
| 439 | error_tcp_socket: |
| 440 | lttng_poll_clean(&events); |
| 441 | error_poll_create: |
| 442 | uatomic_set(&agent_tracing_enabled, 0); |
| 443 | DBG("[agent-thread] is cleaning up and stopping."); |
| 444 | |
| 445 | rcu_thread_offline(); |
| 446 | rcu_unregister_thread(); |
| 447 | return NULL; |
| 448 | } |