| 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 _GNU_SOURCE |
| 19 | #define _LGPL_SOURCE |
| 20 | #include <assert.h> |
| 21 | |
| 22 | #include <common/common.h> |
| 23 | #include <common/sessiond-comm/sessiond-comm.h> |
| 24 | #include <common/uri.h> |
| 25 | #include <common/utils.h> |
| 26 | |
| 27 | #include <common/compat/endian.h> |
| 28 | |
| 29 | #include "fd-limit.h" |
| 30 | #include "agent-thread.h" |
| 31 | #include "lttng-sessiond.h" |
| 32 | #include "session.h" |
| 33 | #include "utils.h" |
| 34 | |
| 35 | /* |
| 36 | * Note that there is not port here. It's set after this URI is parsed so we |
| 37 | * can let the user define a custom one. However, localhost is ALWAYS the |
| 38 | * default listening address. |
| 39 | */ |
| 40 | static const char *default_reg_uri = |
| 41 | "tcp://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS; |
| 42 | |
| 43 | /* |
| 44 | * Update agent application using the given socket. This is done just after |
| 45 | * registration was successful. |
| 46 | * |
| 47 | * This is a quite heavy call in terms of locking since the session list lock |
| 48 | * AND session lock are acquired. |
| 49 | */ |
| 50 | static void update_agent_app(struct agent_app *app) |
| 51 | { |
| 52 | struct ltt_session *session, *stmp; |
| 53 | struct ltt_session_list *list; |
| 54 | |
| 55 | list = session_get_list(); |
| 56 | assert(list); |
| 57 | |
| 58 | session_lock_list(); |
| 59 | cds_list_for_each_entry_safe(session, stmp, &list->head, list) { |
| 60 | session_lock(session); |
| 61 | if (session->ust_session) { |
| 62 | struct agent *agt; |
| 63 | |
| 64 | rcu_read_lock(); |
| 65 | agt = trace_ust_find_agent(session->ust_session, app->domain); |
| 66 | if (agt) { |
| 67 | agent_update(agt, app->sock->fd); |
| 68 | } |
| 69 | rcu_read_unlock(); |
| 70 | } |
| 71 | session_unlock(session); |
| 72 | } |
| 73 | session_unlock_list(); |
| 74 | } |
| 75 | |
| 76 | /* |
| 77 | * Destroy a agent application by socket. |
| 78 | */ |
| 79 | static void destroy_agent_app(int sock) |
| 80 | { |
| 81 | struct agent_app *app; |
| 82 | |
| 83 | assert(sock >= 0); |
| 84 | |
| 85 | /* |
| 86 | * Not finding an application is a very important error that should NEVER |
| 87 | * happen. The hash table deletion is ONLY done through this call even on |
| 88 | * thread cleanup. |
| 89 | */ |
| 90 | rcu_read_lock(); |
| 91 | app = agent_find_app_by_sock(sock); |
| 92 | assert(app); |
| 93 | rcu_read_unlock(); |
| 94 | |
| 95 | /* RCU read side lock is taken in this function call. */ |
| 96 | agent_delete_app(app); |
| 97 | |
| 98 | /* The application is freed in a RCU call but the socket is closed here. */ |
| 99 | agent_destroy_app(app); |
| 100 | } |
| 101 | |
| 102 | /* |
| 103 | * Cleanup remaining agent apps in the hash table. This should only be called in |
| 104 | * the exit path of the thread. |
| 105 | */ |
| 106 | static void clean_agent_apps_ht(void) |
| 107 | { |
| 108 | struct lttng_ht_node_ulong *node; |
| 109 | struct lttng_ht_iter iter; |
| 110 | |
| 111 | DBG3("[agent-thread] Cleaning agent apps ht"); |
| 112 | |
| 113 | rcu_read_lock(); |
| 114 | cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) { |
| 115 | struct agent_app *app; |
| 116 | |
| 117 | app = caa_container_of(node, struct agent_app, node); |
| 118 | destroy_agent_app(app->sock->fd); |
| 119 | } |
| 120 | rcu_read_unlock(); |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * Create and init socket from uri. |
| 125 | */ |
| 126 | static struct lttcomm_sock *init_tcp_socket(void) |
| 127 | { |
| 128 | int ret; |
| 129 | struct lttng_uri *uri = NULL; |
| 130 | struct lttcomm_sock *sock = NULL; |
| 131 | |
| 132 | /* |
| 133 | * This should never fail since the URI is hardcoded and the port is set |
| 134 | * before this thread is launched. |
| 135 | */ |
| 136 | ret = uri_parse(default_reg_uri, &uri); |
| 137 | assert(ret); |
| 138 | assert(agent_tcp_port); |
| 139 | uri->port = agent_tcp_port; |
| 140 | |
| 141 | sock = lttcomm_alloc_sock_from_uri(uri); |
| 142 | uri_free(uri); |
| 143 | if (sock == NULL) { |
| 144 | ERR("[agent-thread] agent allocating TCP socket"); |
| 145 | goto error; |
| 146 | } |
| 147 | |
| 148 | ret = lttcomm_create_sock(sock); |
| 149 | if (ret < 0) { |
| 150 | goto error; |
| 151 | } |
| 152 | |
| 153 | ret = sock->ops->bind(sock); |
| 154 | if (ret < 0) { |
| 155 | WARN("Another session daemon is using this agent port. Agent support " |
| 156 | "will be deactivated to prevent interfering with the tracing."); |
| 157 | goto error; |
| 158 | } |
| 159 | |
| 160 | ret = sock->ops->listen(sock, -1); |
| 161 | if (ret < 0) { |
| 162 | goto error; |
| 163 | } |
| 164 | |
| 165 | DBG("[agent-thread] Listening on TCP port %u and socket %d", |
| 166 | agent_tcp_port, sock->fd); |
| 167 | |
| 168 | return sock; |
| 169 | |
| 170 | error: |
| 171 | if (sock) { |
| 172 | lttcomm_destroy_sock(sock); |
| 173 | } |
| 174 | return NULL; |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * Close and destroy the given TCP socket. |
| 179 | */ |
| 180 | static void destroy_tcp_socket(struct lttcomm_sock *sock) |
| 181 | { |
| 182 | assert(sock); |
| 183 | |
| 184 | DBG3("[agent-thread] Destroy TCP socket on port %u", agent_tcp_port); |
| 185 | |
| 186 | /* This will return gracefully if fd is invalid. */ |
| 187 | sock->ops->close(sock); |
| 188 | lttcomm_destroy_sock(sock); |
| 189 | } |
| 190 | |
| 191 | /* |
| 192 | * Handle a new agent registration using the reg socket. After that, a new |
| 193 | * agent application is added to the global hash table and attach to an UST app |
| 194 | * object. If r_app is not NULL, the created app is set to the pointer. |
| 195 | * |
| 196 | * Return the new FD created upon accept() on success or else a negative errno |
| 197 | * value. |
| 198 | */ |
| 199 | static int handle_registration(struct lttcomm_sock *reg_sock, |
| 200 | struct agent_app **r_app) |
| 201 | { |
| 202 | int ret; |
| 203 | pid_t pid; |
| 204 | uint32_t major_version, minor_version; |
| 205 | ssize_t size; |
| 206 | enum lttng_domain_type domain; |
| 207 | struct agent_app *app; |
| 208 | struct agent_register_msg msg; |
| 209 | struct lttcomm_sock *new_sock; |
| 210 | |
| 211 | assert(reg_sock); |
| 212 | |
| 213 | new_sock = reg_sock->ops->accept(reg_sock); |
| 214 | if (!new_sock) { |
| 215 | ret = -ENOTCONN; |
| 216 | goto error; |
| 217 | } |
| 218 | |
| 219 | size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0); |
| 220 | if (size < sizeof(msg)) { |
| 221 | ret = -EINVAL; |
| 222 | goto error_socket; |
| 223 | } |
| 224 | domain = be32toh(msg.domain); |
| 225 | pid = be32toh(msg.pid); |
| 226 | major_version = be32toh(msg.major_version); |
| 227 | minor_version = be32toh(msg.minor_version); |
| 228 | |
| 229 | /* Test communication protocol version of the registring agent. */ |
| 230 | if (major_version != AGENT_MAJOR_VERSION) { |
| 231 | ret = -EINVAL; |
| 232 | goto error_socket; |
| 233 | } |
| 234 | if (minor_version != AGENT_MINOR_VERSION) { |
| 235 | ret = -EINVAL; |
| 236 | goto error_socket; |
| 237 | } |
| 238 | |
| 239 | DBG2("[agent-thread] New registration for pid %d domain %d on socket %d", |
| 240 | pid, domain, new_sock->fd); |
| 241 | |
| 242 | app = agent_create_app(pid, domain, new_sock); |
| 243 | if (!app) { |
| 244 | ret = -ENOMEM; |
| 245 | goto error_socket; |
| 246 | } |
| 247 | |
| 248 | /* |
| 249 | * Add before assigning the socket value to the UST app so it can be found |
| 250 | * concurrently. |
| 251 | */ |
| 252 | agent_add_app(app); |
| 253 | |
| 254 | /* |
| 255 | * We don't need to attach the agent app to the app. If we ever do so, we |
| 256 | * should consider both registration order of agent before app and app |
| 257 | * before agent. |
| 258 | */ |
| 259 | |
| 260 | if (r_app) { |
| 261 | *r_app = app; |
| 262 | } |
| 263 | |
| 264 | return new_sock->fd; |
| 265 | |
| 266 | error_socket: |
| 267 | new_sock->ops->close(new_sock); |
| 268 | lttcomm_destroy_sock(new_sock); |
| 269 | error: |
| 270 | return ret; |
| 271 | } |
| 272 | |
| 273 | /* |
| 274 | * This thread manage application notify communication. |
| 275 | */ |
| 276 | void *agent_thread_manage_registration(void *data) |
| 277 | { |
| 278 | int i, ret, pollfd; |
| 279 | uint32_t revents, nb_fd; |
| 280 | struct lttng_poll_event events; |
| 281 | struct lttcomm_sock *reg_sock; |
| 282 | |
| 283 | DBG("[agent-thread] Manage agent application registration."); |
| 284 | |
| 285 | rcu_register_thread(); |
| 286 | rcu_thread_online(); |
| 287 | |
| 288 | /* Agent initialization call MUST be called before starting the thread. */ |
| 289 | assert(agent_apps_ht_by_sock); |
| 290 | |
| 291 | /* Create pollset with size 2, quit pipe and socket. */ |
| 292 | ret = sessiond_set_thread_pollset(&events, 2); |
| 293 | if (ret < 0) { |
| 294 | goto error_poll_create; |
| 295 | } |
| 296 | |
| 297 | reg_sock = init_tcp_socket(); |
| 298 | if (!reg_sock) { |
| 299 | goto error_tcp_socket; |
| 300 | } |
| 301 | |
| 302 | /* Add create valid TCP socket to poll set. */ |
| 303 | ret = lttng_poll_add(&events, reg_sock->fd, |
| 304 | LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP); |
| 305 | if (ret < 0) { |
| 306 | goto error; |
| 307 | } |
| 308 | |
| 309 | while (1) { |
| 310 | DBG3("[agent-thread] Manage agent polling on %d fds", |
| 311 | LTTNG_POLL_GETNB(&events)); |
| 312 | |
| 313 | /* Inifinite blocking call, waiting for transmission */ |
| 314 | restart: |
| 315 | ret = lttng_poll_wait(&events, -1); |
| 316 | if (ret < 0) { |
| 317 | /* |
| 318 | * Restart interrupted system call. |
| 319 | */ |
| 320 | if (errno == EINTR) { |
| 321 | goto restart; |
| 322 | } |
| 323 | goto error; |
| 324 | } |
| 325 | nb_fd = ret; |
| 326 | DBG3("[agent-thread] %d fd ready", nb_fd); |
| 327 | |
| 328 | for (i = 0; i < nb_fd; i++) { |
| 329 | /* Fetch once the poll data */ |
| 330 | revents = LTTNG_POLL_GETEV(&events, i); |
| 331 | pollfd = LTTNG_POLL_GETFD(&events, i); |
| 332 | |
| 333 | /* Thread quit pipe has been closed. Killing thread. */ |
| 334 | ret = sessiond_check_thread_quit_pipe(pollfd, revents); |
| 335 | if (ret) { |
| 336 | goto exit; |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * Check first if this is a POLLERR since POLLIN is also included |
| 341 | * in an error value thus checking first. |
| 342 | */ |
| 343 | if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 344 | /* Removing from the poll set */ |
| 345 | ret = lttng_poll_del(&events, pollfd); |
| 346 | if (ret < 0) { |
| 347 | goto error; |
| 348 | } |
| 349 | |
| 350 | destroy_agent_app(pollfd); |
| 351 | } else if (revents & (LPOLLIN)) { |
| 352 | int new_fd; |
| 353 | struct agent_app *app = NULL; |
| 354 | |
| 355 | /* Pollin event of agent app socket should NEVER happen. */ |
| 356 | assert(pollfd == reg_sock->fd); |
| 357 | |
| 358 | new_fd = handle_registration(reg_sock, &app); |
| 359 | if (new_fd < 0) { |
| 360 | WARN("[agent-thread] agent registration failed. Ignoring."); |
| 361 | /* Somehow the communication failed. Just continue. */ |
| 362 | continue; |
| 363 | } |
| 364 | /* Should not have a NULL app on success. */ |
| 365 | assert(app); |
| 366 | |
| 367 | /* Only add poll error event to only detect shutdown. */ |
| 368 | ret = lttng_poll_add(&events, new_fd, |
| 369 | LPOLLERR | LPOLLHUP | LPOLLRDHUP); |
| 370 | if (ret < 0) { |
| 371 | destroy_agent_app(new_fd); |
| 372 | continue; |
| 373 | } |
| 374 | |
| 375 | /* Update newly registered app. */ |
| 376 | update_agent_app(app); |
| 377 | |
| 378 | /* On failure, the poll will detect it and clean it up. */ |
| 379 | (void) agent_send_registration_done(app); |
| 380 | } else { |
| 381 | ERR("Unknown poll events %u for sock %d", revents, pollfd); |
| 382 | continue; |
| 383 | } |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | exit: |
| 388 | /* Whatever happens, try to delete it and exit. */ |
| 389 | (void) lttng_poll_del(&events, reg_sock->fd); |
| 390 | error: |
| 391 | destroy_tcp_socket(reg_sock); |
| 392 | error_tcp_socket: |
| 393 | lttng_poll_clean(&events); |
| 394 | error_poll_create: |
| 395 | DBG("[agent-thread] is cleaning up and stopping."); |
| 396 | |
| 397 | if (agent_apps_ht_by_sock) { |
| 398 | clean_agent_apps_ht(); |
| 399 | lttng_ht_destroy(agent_apps_ht_by_sock); |
| 400 | } |
| 401 | |
| 402 | rcu_thread_offline(); |
| 403 | rcu_unregister_thread(); |
| 404 | return NULL; |
| 405 | } |