1 /* $OpenBSD: server.c,v 1.122 2015/04/24 23:17:11 nicm Exp $ */ 2 3 /* 4 * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER 15 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 16 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/ioctl.h> 21 #include <sys/socket.h> 22 #include <sys/stat.h> 23 #include <sys/un.h> 24 #include <sys/wait.h> 25 26 #include <errno.h> 27 #include <event.h> 28 #include <fcntl.h> 29 #include <paths.h> 30 #include <signal.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <syslog.h> 35 #include <termios.h> 36 #include <time.h> 37 #include <unistd.h> 38 39 #include "tmux.h" 40 41 /* 42 * Main server functions. 43 */ 44 45 /* Client list. */ 46 struct clients clients; 47 struct clients dead_clients; 48 49 int server_fd; 50 int server_shutdown; 51 struct event server_ev_accept; 52 struct event server_ev_second; 53 54 int server_create_socket(void); 55 void server_loop(void); 56 int server_should_shutdown(void); 57 void server_send_shutdown(void); 58 void server_clean_dead(void); 59 void server_accept_callback(int, short, void *); 60 void server_signal_callback(int, short, void *); 61 void server_child_signal(void); 62 void server_child_exited(pid_t, int); 63 void server_child_stopped(pid_t, int); 64 void server_second_callback(int, short, void *); 65 void server_lock_server(void); 66 void server_lock_sessions(void); 67 68 /* Create server socket. */ 69 int 70 server_create_socket(void) 71 { 72 struct sockaddr_un sa; 73 size_t size; 74 mode_t mask; 75 int fd; 76 77 memset(&sa, 0, sizeof sa); 78 sa.sun_family = AF_UNIX; 79 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 80 if (size >= sizeof sa.sun_path) { 81 errno = ENAMETOOLONG; 82 return (-1); 83 } 84 unlink(sa.sun_path); 85 86 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 87 return (-1); 88 89 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 90 if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) 91 return (-1); 92 umask(mask); 93 94 if (listen(fd, 16) == -1) 95 return (-1); 96 setblocking(fd, 0); 97 98 return (fd); 99 } 100 101 /* Fork new server. */ 102 int 103 server_start(int lockfd, char *lockfile) 104 { 105 int pair[2]; 106 struct timeval tv; 107 char *cause; 108 109 /* The first client is special and gets a socketpair; create it. */ 110 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 111 fatal("socketpair failed"); 112 log_debug("starting server"); 113 114 switch (fork()) { 115 case -1: 116 fatal("fork failed"); 117 case 0: 118 break; 119 default: 120 close(pair[1]); 121 return (pair[0]); 122 } 123 close(pair[0]); 124 125 /* 126 * Must daemonise before loading configuration as the PID changes so 127 * $TMUX would be wrong for sessions created in the config file. 128 */ 129 if (daemon(1, 0) != 0) 130 fatal("daemon failed"); 131 132 /* event_init() was called in our parent, need to reinit. */ 133 if (event_reinit(ev_base) != 0) 134 fatal("event_reinit failed"); 135 clear_signals(0); 136 137 logfile("server"); 138 log_debug("server started, pid %ld", (long) getpid()); 139 140 RB_INIT(&windows); 141 RB_INIT(&all_window_panes); 142 TAILQ_INIT(&clients); 143 TAILQ_INIT(&dead_clients); 144 RB_INIT(&sessions); 145 RB_INIT(&dead_sessions); 146 TAILQ_INIT(&session_groups); 147 mode_key_init_trees(); 148 key_bindings_init(); 149 utf8_build(); 150 151 start_time = time(NULL); 152 log_debug("socket path %s", socket_path); 153 setproctitle("server (%s)", socket_path); 154 155 server_fd = server_create_socket(); 156 if (server_fd == -1) 157 fatal("couldn't create socket"); 158 server_update_socket(); 159 server_client_create(pair[1]); 160 161 unlink(lockfile); 162 free(lockfile); 163 close(lockfd); 164 165 cfg_cmd_q = cmdq_new(NULL); 166 cfg_cmd_q->emptyfn = cfg_default_done; 167 cfg_finished = 0; 168 cfg_references = 1; 169 cfg_client = TAILQ_FIRST(&clients); 170 if (cfg_client != NULL) 171 cfg_client->references++; 172 173 if (access(TMUX_CONF, R_OK) == 0) { 174 if (load_cfg(TMUX_CONF, cfg_cmd_q, &cause) == -1) 175 cfg_add_cause("%s: %s", TMUX_CONF, cause); 176 } else if (errno != ENOENT) 177 cfg_add_cause("%s: %s", TMUX_CONF, strerror(errno)); 178 if (cfg_file != NULL) { 179 if (load_cfg(cfg_file, cfg_cmd_q, &cause) == -1) 180 cfg_add_cause("%s: %s", cfg_file, cause); 181 } 182 cmdq_continue(cfg_cmd_q); 183 184 server_add_accept(0); 185 186 memset(&tv, 0, sizeof tv); 187 tv.tv_sec = 1; 188 evtimer_set(&server_ev_second, server_second_callback, NULL); 189 evtimer_add(&server_ev_second, &tv); 190 191 set_signals(server_signal_callback); 192 server_loop(); 193 exit(0); 194 } 195 196 /* Main server loop. */ 197 void 198 server_loop(void) 199 { 200 while (!server_should_shutdown()) { 201 event_loop(EVLOOP_ONCE); 202 203 server_window_loop(); 204 server_client_loop(); 205 206 server_clean_dead(); 207 } 208 } 209 210 /* Check if the server should exit (no more clients or sessions). */ 211 int 212 server_should_shutdown(void) 213 { 214 struct client *c; 215 216 if (!options_get_number(&global_options, "exit-unattached")) { 217 if (!RB_EMPTY(&sessions)) 218 return (0); 219 } 220 221 TAILQ_FOREACH(c, &clients, entry) { 222 if (c->session != NULL) 223 return (0); 224 } 225 226 /* 227 * No attached clients therefore want to exit - flush any waiting 228 * clients but don't actually exit until they've gone. 229 */ 230 cmd_wait_for_flush(); 231 if (!TAILQ_EMPTY(&clients)) 232 return (0); 233 234 return (1); 235 } 236 237 /* Shutdown the server by killing all clients and windows. */ 238 void 239 server_send_shutdown(void) 240 { 241 struct client *c, *c1; 242 struct session *s, *s1; 243 244 cmd_wait_for_flush(); 245 246 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 247 if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED)) 248 server_client_lost(c); 249 else 250 server_write_client(c, MSG_SHUTDOWN, NULL, 0); 251 c->session = NULL; 252 } 253 254 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 255 session_destroy(s); 256 } 257 258 /* Free dead, unreferenced clients and sessions. */ 259 void 260 server_clean_dead(void) 261 { 262 struct session *s, *s1; 263 struct client *c, *c1; 264 265 RB_FOREACH_SAFE(s, sessions, &dead_sessions, s1) { 266 if (s->references != 0) 267 continue; 268 RB_REMOVE(sessions, &dead_sessions, s); 269 free(s->name); 270 free(s); 271 } 272 273 TAILQ_FOREACH_SAFE(c, &dead_clients, entry, c1) { 274 if (c->references != 0) 275 continue; 276 TAILQ_REMOVE(&dead_clients, c, entry); 277 free(c); 278 } 279 } 280 281 /* Update socket execute permissions based on whether sessions are attached. */ 282 void 283 server_update_socket(void) 284 { 285 struct session *s; 286 static int last = -1; 287 int n, mode; 288 struct stat sb; 289 290 n = 0; 291 RB_FOREACH(s, sessions, &sessions) { 292 if (!(s->flags & SESSION_UNATTACHED)) { 293 n++; 294 break; 295 } 296 } 297 298 if (n != last) { 299 last = n; 300 301 if (stat(socket_path, &sb) != 0) 302 return; 303 mode = sb.st_mode; 304 if (n != 0) { 305 if (mode & S_IRUSR) 306 mode |= S_IXUSR; 307 if (mode & S_IRGRP) 308 mode |= S_IXGRP; 309 if (mode & S_IROTH) 310 mode |= S_IXOTH; 311 } else 312 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 313 chmod(socket_path, mode); 314 } 315 } 316 317 /* Callback for server socket. */ 318 void 319 server_accept_callback(int fd, short events, unused void *data) 320 { 321 struct sockaddr_storage sa; 322 socklen_t slen = sizeof sa; 323 int newfd; 324 325 server_add_accept(0); 326 if (!(events & EV_READ)) 327 return; 328 329 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 330 if (newfd == -1) { 331 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 332 return; 333 if (errno == ENFILE || errno == EMFILE) { 334 /* Delete and don't try again for 1 second. */ 335 server_add_accept(1); 336 return; 337 } 338 fatal("accept failed"); 339 } 340 if (server_shutdown) { 341 close(newfd); 342 return; 343 } 344 server_client_create(newfd); 345 } 346 347 /* 348 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 349 * event - used to backoff when running out of file descriptors. 350 */ 351 void 352 server_add_accept(int timeout) 353 { 354 struct timeval tv = { timeout, 0 }; 355 356 if (event_initialized(&server_ev_accept)) 357 event_del(&server_ev_accept); 358 359 if (timeout == 0) { 360 event_set(&server_ev_accept, 361 server_fd, EV_READ, server_accept_callback, NULL); 362 event_add(&server_ev_accept, NULL); 363 } else { 364 event_set(&server_ev_accept, 365 server_fd, EV_TIMEOUT, server_accept_callback, NULL); 366 event_add(&server_ev_accept, &tv); 367 } 368 } 369 370 /* Signal handler. */ 371 void 372 server_signal_callback(int sig, unused short events, unused void *data) 373 { 374 int fd; 375 376 switch (sig) { 377 case SIGTERM: 378 server_shutdown = 1; 379 server_send_shutdown(); 380 break; 381 case SIGCHLD: 382 server_child_signal(); 383 break; 384 case SIGUSR1: 385 event_del(&server_ev_accept); 386 fd = server_create_socket(); 387 if (fd != -1) { 388 close(server_fd); 389 server_fd = fd; 390 server_update_socket(); 391 } 392 server_add_accept(0); 393 break; 394 } 395 } 396 397 /* Handle SIGCHLD. */ 398 void 399 server_child_signal(void) 400 { 401 int status; 402 pid_t pid; 403 404 for (;;) { 405 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 406 case -1: 407 if (errno == ECHILD) 408 return; 409 fatal("waitpid failed"); 410 case 0: 411 return; 412 } 413 if (WIFSTOPPED(status)) 414 server_child_stopped(pid, status); 415 else if (WIFEXITED(status) || WIFSIGNALED(status)) 416 server_child_exited(pid, status); 417 } 418 } 419 420 /* Handle exited children. */ 421 void 422 server_child_exited(pid_t pid, int status) 423 { 424 struct window *w, *w1; 425 struct window_pane *wp; 426 struct job *job; 427 428 RB_FOREACH_SAFE(w, windows, &windows, w1) { 429 TAILQ_FOREACH(wp, &w->panes, entry) { 430 if (wp->pid == pid) { 431 wp->status = status; 432 server_destroy_pane(wp); 433 break; 434 } 435 } 436 } 437 438 LIST_FOREACH(job, &all_jobs, lentry) { 439 if (pid == job->pid) { 440 job_died(job, status); /* might free job */ 441 break; 442 } 443 } 444 } 445 446 /* Handle stopped children. */ 447 void 448 server_child_stopped(pid_t pid, int status) 449 { 450 struct window *w; 451 struct window_pane *wp; 452 453 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 454 return; 455 456 RB_FOREACH(w, windows, &windows) { 457 TAILQ_FOREACH(wp, &w->panes, entry) { 458 if (wp->pid == pid) { 459 if (killpg(pid, SIGCONT) != 0) 460 kill(pid, SIGCONT); 461 } 462 } 463 } 464 } 465 466 /* Handle once-per-second timer events. */ 467 void 468 server_second_callback(unused int fd, unused short events, unused void *arg) 469 { 470 struct window *w; 471 struct window_pane *wp; 472 struct timeval tv; 473 474 if (options_get_number(&global_s_options, "lock-server")) 475 server_lock_server(); 476 else 477 server_lock_sessions(); 478 479 RB_FOREACH(w, windows, &windows) { 480 TAILQ_FOREACH(wp, &w->panes, entry) { 481 if (wp->mode != NULL && wp->mode->timer != NULL) 482 wp->mode->timer(wp); 483 } 484 } 485 486 server_client_status_timer(); 487 488 evtimer_del(&server_ev_second); 489 memset(&tv, 0, sizeof tv); 490 tv.tv_sec = 1; 491 evtimer_add(&server_ev_second, &tv); 492 } 493 494 /* Lock the server if ALL sessions have hit the time limit. */ 495 void 496 server_lock_server(void) 497 { 498 struct session *s; 499 int timeout; 500 time_t t; 501 502 t = time(NULL); 503 RB_FOREACH(s, sessions, &sessions) { 504 if (s->flags & SESSION_UNATTACHED) 505 continue; 506 timeout = options_get_number(&s->options, "lock-after-time"); 507 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout) 508 return; /* not timed out */ 509 } 510 511 server_lock(); 512 recalculate_sizes(); 513 } 514 515 /* Lock any sessions which have timed out. */ 516 void 517 server_lock_sessions(void) 518 { 519 struct session *s; 520 int timeout; 521 time_t t; 522 523 t = time(NULL); 524 RB_FOREACH(s, sessions, &sessions) { 525 if (s->flags & SESSION_UNATTACHED) 526 continue; 527 timeout = options_get_number(&s->options, "lock-after-time"); 528 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) { 529 server_lock_session(s); 530 recalculate_sizes(); 531 } 532 } 533 } 534