1 /* $OpenBSD: server.c,v 1.117 2014/10/27 22:23:47 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 fatal("socket failed"); 83 } 84 unlink(sa.sun_path); 85 86 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 87 fatal("socket failed"); 88 89 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 90 if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) 91 fatal("bind failed"); 92 umask(mask); 93 94 if (listen(fd, 16) == -1) 95 fatal("listen failed"); 96 setblocking(fd, 0); 97 98 server_update_socket(); 99 100 return (fd); 101 } 102 103 /* Fork new server. */ 104 int 105 server_start(int lockfd, char *lockfile) 106 { 107 int pair[2]; 108 struct timeval tv; 109 char *cause; 110 111 /* The first client is special and gets a socketpair; create it. */ 112 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 113 fatal("socketpair failed"); 114 log_debug("starting server"); 115 116 switch (fork()) { 117 case -1: 118 fatal("fork failed"); 119 case 0: 120 break; 121 default: 122 close(pair[1]); 123 return (pair[0]); 124 } 125 close(pair[0]); 126 127 /* 128 * Must daemonise before loading configuration as the PID changes so 129 * $TMUX would be wrong for sessions created in the config file. 130 */ 131 if (daemon(1, 0) != 0) 132 fatal("daemon failed"); 133 134 /* event_init() was called in our parent, need to reinit. */ 135 if (event_reinit(ev_base) != 0) 136 fatal("event_reinit failed"); 137 clear_signals(0); 138 139 logfile("server"); 140 log_debug("server started, pid %ld", (long) getpid()); 141 142 ARRAY_INIT(&windows); 143 RB_INIT(&all_window_panes); 144 ARRAY_INIT(&clients); 145 ARRAY_INIT(&dead_clients); 146 RB_INIT(&sessions); 147 RB_INIT(&dead_sessions); 148 TAILQ_INIT(&session_groups); 149 mode_key_init_trees(); 150 key_bindings_init(); 151 utf8_build(); 152 153 start_time = time(NULL); 154 log_debug("socket path %s", socket_path); 155 setproctitle("server (%s)", socket_path); 156 157 server_fd = server_create_socket(); 158 server_client_create(pair[1]); 159 160 unlink(lockfile); 161 free(lockfile); 162 close(lockfd); 163 164 cfg_cmd_q = cmdq_new(NULL); 165 cfg_cmd_q->emptyfn = cfg_default_done; 166 cfg_finished = 0; 167 cfg_references = 1; 168 cfg_client = ARRAY_FIRST(&clients); 169 if (cfg_client != NULL) 170 cfg_client->references++; 171 172 if (access(TMUX_CONF, R_OK) == 0) { 173 if (load_cfg(TMUX_CONF, cfg_cmd_q, &cause) == -1) 174 cfg_add_cause("%s: %s", TMUX_CONF, cause); 175 } else if (errno != ENOENT) 176 cfg_add_cause("%s: %s", TMUX_CONF, strerror(errno)); 177 if (cfg_file != NULL) { 178 if (load_cfg(cfg_file, cfg_cmd_q, &cause) == -1) 179 cfg_add_cause("%s: %s", cfg_file, cause); 180 } 181 cmdq_continue(cfg_cmd_q); 182 183 server_add_accept(0); 184 185 memset(&tv, 0, sizeof tv); 186 tv.tv_sec = 1; 187 evtimer_set(&server_ev_second, server_second_callback, NULL); 188 evtimer_add(&server_ev_second, &tv); 189 190 set_signals(server_signal_callback); 191 server_loop(); 192 exit(0); 193 } 194 195 /* Main server loop. */ 196 void 197 server_loop(void) 198 { 199 while (!server_should_shutdown()) { 200 event_loop(EVLOOP_ONCE); 201 202 server_window_loop(); 203 server_client_loop(); 204 205 server_clean_dead(); 206 } 207 } 208 209 /* Check if the server should exit (no more clients or sessions). */ 210 int 211 server_should_shutdown(void) 212 { 213 struct client *c; 214 u_int i; 215 216 if (!options_get_number(&global_options, "exit-unattached")) { 217 if (!RB_EMPTY(&sessions)) 218 return (0); 219 } 220 221 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 222 c = ARRAY_ITEM(&clients, i); 223 if (c != NULL && c->session != NULL) 224 return (0); 225 } 226 227 /* 228 * No attached clients therefore want to exit - flush any waiting 229 * clients but don't actually exit until they've gone. 230 */ 231 cmd_wait_for_flush(); 232 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 233 if (ARRAY_ITEM(&clients, i) != NULL) 234 return (0); 235 } 236 237 return (1); 238 } 239 240 /* Shutdown the server by killing all clients and windows. */ 241 void 242 server_send_shutdown(void) 243 { 244 struct client *c; 245 struct session *s, *next_s; 246 u_int i; 247 248 cmd_wait_for_flush(); 249 250 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 251 c = ARRAY_ITEM(&clients, i); 252 if (c != NULL) { 253 if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED)) 254 server_client_lost(c); 255 else 256 server_write_client(c, MSG_SHUTDOWN, NULL, 0); 257 c->session = NULL; 258 } 259 } 260 261 s = RB_MIN(sessions, &sessions); 262 while (s != NULL) { 263 next_s = RB_NEXT(sessions, &sessions, s); 264 session_destroy(s); 265 s = next_s; 266 } 267 } 268 269 /* Free dead, unreferenced clients and sessions. */ 270 void 271 server_clean_dead(void) 272 { 273 struct session *s, *next_s; 274 struct client *c; 275 u_int i; 276 277 s = RB_MIN(sessions, &dead_sessions); 278 while (s != NULL) { 279 next_s = RB_NEXT(sessions, &dead_sessions, s); 280 if (s->references == 0) { 281 RB_REMOVE(sessions, &dead_sessions, s); 282 free(s->name); 283 free(s); 284 } 285 s = next_s; 286 } 287 288 for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) { 289 c = ARRAY_ITEM(&dead_clients, i); 290 if (c == NULL || c->references != 0) 291 continue; 292 ARRAY_SET(&dead_clients, i, NULL); 293 free(c); 294 } 295 } 296 297 /* Update socket execute permissions based on whether sessions are attached. */ 298 void 299 server_update_socket(void) 300 { 301 struct session *s; 302 static int last = -1; 303 int n, mode; 304 struct stat sb; 305 306 n = 0; 307 RB_FOREACH(s, sessions, &sessions) { 308 if (!(s->flags & SESSION_UNATTACHED)) { 309 n++; 310 break; 311 } 312 } 313 314 if (n != last) { 315 last = n; 316 317 if (stat(socket_path, &sb) != 0) 318 return; 319 mode = sb.st_mode; 320 if (n != 0) { 321 if (mode & S_IRUSR) 322 mode |= S_IXUSR; 323 if (mode & S_IRGRP) 324 mode |= S_IXGRP; 325 if (mode & S_IROTH) 326 mode |= S_IXOTH; 327 } else 328 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 329 chmod(socket_path, mode); 330 } 331 } 332 333 /* Callback for server socket. */ 334 void 335 server_accept_callback(int fd, short events, unused void *data) 336 { 337 struct sockaddr_storage sa; 338 socklen_t slen = sizeof sa; 339 int newfd; 340 341 server_add_accept(0); 342 if (!(events & EV_READ)) 343 return; 344 345 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 346 if (newfd == -1) { 347 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 348 return; 349 if (errno == ENFILE || errno == EMFILE) { 350 /* Delete and don't try again for 1 second. */ 351 server_add_accept(1); 352 return; 353 } 354 fatal("accept failed"); 355 } 356 if (server_shutdown) { 357 close(newfd); 358 return; 359 } 360 server_client_create(newfd); 361 } 362 363 /* 364 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 365 * event - used to backoff when running out of file descriptors. 366 */ 367 void 368 server_add_accept(int timeout) 369 { 370 struct timeval tv = { timeout, 0 }; 371 372 if (event_initialized(&server_ev_accept)) 373 event_del(&server_ev_accept); 374 375 if (timeout == 0) { 376 event_set(&server_ev_accept, 377 server_fd, EV_READ, server_accept_callback, NULL); 378 event_add(&server_ev_accept, NULL); 379 } else { 380 event_set(&server_ev_accept, 381 server_fd, EV_TIMEOUT, server_accept_callback, NULL); 382 event_add(&server_ev_accept, &tv); 383 } 384 } 385 386 /* Signal handler. */ 387 void 388 server_signal_callback(int sig, unused short events, unused void *data) 389 { 390 switch (sig) { 391 case SIGTERM: 392 server_shutdown = 1; 393 server_send_shutdown(); 394 break; 395 case SIGCHLD: 396 server_child_signal(); 397 break; 398 case SIGUSR1: 399 event_del(&server_ev_accept); 400 close(server_fd); 401 server_fd = server_create_socket(); 402 server_add_accept(0); 403 break; 404 } 405 } 406 407 /* Handle SIGCHLD. */ 408 void 409 server_child_signal(void) 410 { 411 int status; 412 pid_t pid; 413 414 for (;;) { 415 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 416 case -1: 417 if (errno == ECHILD) 418 return; 419 fatal("waitpid failed"); 420 case 0: 421 return; 422 } 423 if (WIFSTOPPED(status)) 424 server_child_stopped(pid, status); 425 else if (WIFEXITED(status) || WIFSIGNALED(status)) 426 server_child_exited(pid, status); 427 } 428 } 429 430 /* Handle exited children. */ 431 void 432 server_child_exited(pid_t pid, int status) 433 { 434 struct window *w; 435 struct window_pane *wp; 436 struct job *job; 437 u_int i; 438 439 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 440 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 441 continue; 442 TAILQ_FOREACH(wp, &w->panes, entry) { 443 if (wp->pid == pid) { 444 server_destroy_pane(wp); 445 break; 446 } 447 } 448 } 449 450 LIST_FOREACH(job, &all_jobs, lentry) { 451 if (pid == job->pid) { 452 job_died(job, status); /* might free job */ 453 break; 454 } 455 } 456 } 457 458 /* Handle stopped children. */ 459 void 460 server_child_stopped(pid_t pid, int status) 461 { 462 struct window *w; 463 struct window_pane *wp; 464 u_int i; 465 466 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 467 return; 468 469 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 470 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 471 continue; 472 TAILQ_FOREACH(wp, &w->panes, entry) { 473 if (wp->pid == pid) { 474 if (killpg(pid, SIGCONT) != 0) 475 kill(pid, SIGCONT); 476 } 477 } 478 } 479 } 480 481 /* Handle once-per-second timer events. */ 482 void 483 server_second_callback(unused int fd, unused short events, unused void *arg) 484 { 485 struct window *w; 486 struct window_pane *wp; 487 struct timeval tv; 488 u_int i; 489 490 if (options_get_number(&global_s_options, "lock-server")) 491 server_lock_server(); 492 else 493 server_lock_sessions(); 494 495 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 496 w = ARRAY_ITEM(&windows, i); 497 if (w == NULL) 498 continue; 499 500 TAILQ_FOREACH(wp, &w->panes, entry) { 501 if (wp->mode != NULL && wp->mode->timer != NULL) 502 wp->mode->timer(wp); 503 } 504 } 505 506 server_client_status_timer(); 507 508 evtimer_del(&server_ev_second); 509 memset(&tv, 0, sizeof tv); 510 tv.tv_sec = 1; 511 evtimer_add(&server_ev_second, &tv); 512 } 513 514 /* Lock the server if ALL sessions have hit the time limit. */ 515 void 516 server_lock_server(void) 517 { 518 struct session *s; 519 int timeout; 520 time_t t; 521 522 t = time(NULL); 523 RB_FOREACH(s, sessions, &sessions) { 524 if (s->flags & SESSION_UNATTACHED) 525 continue; 526 timeout = options_get_number(&s->options, "lock-after-time"); 527 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout) 528 return; /* not timed out */ 529 } 530 531 server_lock(); 532 recalculate_sizes(); 533 } 534 535 /* Lock any sessions which have timed out. */ 536 void 537 server_lock_sessions(void) 538 { 539 struct session *s; 540 int timeout; 541 time_t t; 542 543 t = time(NULL); 544 RB_FOREACH(s, sessions, &sessions) { 545 if (s->flags & SESSION_UNATTACHED) 546 continue; 547 timeout = options_get_number(&s->options, "lock-after-time"); 548 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) { 549 server_lock_session(s); 550 recalculate_sizes(); 551 } 552 } 553 } 554