1 /* $OpenBSD: server.c,v 1.105 2012/07/10 11:53:01 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 struct paste_stack global_buffers; 55 56 int server_create_socket(void); 57 void server_loop(void); 58 int server_should_shutdown(void); 59 void server_send_shutdown(void); 60 void server_clean_dead(void); 61 void server_accept_callback(int, short, void *); 62 void server_signal_callback(int, short, void *); 63 void server_child_signal(void); 64 void server_child_exited(pid_t, int); 65 void server_child_stopped(pid_t, int); 66 void server_second_callback(int, short, void *); 67 void server_lock_server(void); 68 void server_lock_sessions(void); 69 70 /* Create server socket. */ 71 int 72 server_create_socket(void) 73 { 74 struct sockaddr_un sa; 75 size_t size; 76 mode_t mask; 77 int fd; 78 79 memset(&sa, 0, sizeof sa); 80 sa.sun_family = AF_UNIX; 81 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 82 if (size >= sizeof sa.sun_path) { 83 errno = ENAMETOOLONG; 84 fatal("socket failed"); 85 } 86 unlink(sa.sun_path); 87 88 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 89 fatal("socket failed"); 90 91 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 92 if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) 93 fatal("bind failed"); 94 umask(mask); 95 96 if (listen(fd, 16) == -1) 97 fatal("listen failed"); 98 setblocking(fd, 0); 99 100 server_update_socket(); 101 102 return (fd); 103 } 104 105 /* Fork new server. */ 106 int 107 server_start(int lockfd, char *lockfile) 108 { 109 struct window_pane *wp; 110 int pair[2]; 111 char *cause; 112 struct timeval tv; 113 u_int i; 114 115 /* The first client is special and gets a socketpair; create it. */ 116 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 117 fatal("socketpair failed"); 118 119 switch (fork()) { 120 case -1: 121 fatal("fork failed"); 122 case 0: 123 break; 124 default: 125 close(pair[1]); 126 return (pair[0]); 127 } 128 close(pair[0]); 129 130 /* 131 * Must daemonise before loading configuration as the PID changes so 132 * $TMUX would be wrong for sessions created in the config file. 133 */ 134 if (daemon(1, 0) != 0) 135 fatal("daemon failed"); 136 137 /* event_init() was called in our parent, need to reinit. */ 138 if (event_reinit(ev_base) != 0) 139 fatal("event_reinit failed"); 140 clear_signals(0); 141 142 logfile("server"); 143 log_debug("server started, pid %ld", (long) getpid()); 144 145 ARRAY_INIT(&windows); 146 RB_INIT(&all_window_panes); 147 ARRAY_INIT(&clients); 148 ARRAY_INIT(&dead_clients); 149 RB_INIT(&sessions); 150 RB_INIT(&dead_sessions); 151 TAILQ_INIT(&session_groups); 152 ARRAY_INIT(&global_buffers); 153 mode_key_init_trees(); 154 key_bindings_init(); 155 utf8_build(); 156 157 start_time = time(NULL); 158 log_debug("socket path %s", socket_path); 159 setproctitle("server (%s)", socket_path); 160 161 server_fd = server_create_socket(); 162 server_client_create(pair[1]); 163 164 unlink(lockfile); 165 free(lockfile); 166 close(lockfd); 167 168 if (access(SYSTEM_CFG, R_OK) == 0) 169 load_cfg(SYSTEM_CFG, NULL, &cfg_causes); 170 else if (errno != ENOENT) { 171 cfg_add_cause( 172 &cfg_causes, "%s: %s", strerror(errno), SYSTEM_CFG); 173 } 174 if (cfg_file != NULL) 175 load_cfg(cfg_file, NULL, &cfg_causes); 176 177 /* 178 * If there is a session already, put the current window and pane into 179 * more mode. 180 */ 181 if (!RB_EMPTY(&sessions) && !ARRAY_EMPTY(&cfg_causes)) { 182 wp = RB_MIN(sessions, &sessions)->curw->window->active; 183 window_pane_set_mode(wp, &window_copy_mode); 184 window_copy_init_for_output(wp); 185 for (i = 0; i < ARRAY_LENGTH(&cfg_causes); i++) { 186 cause = ARRAY_ITEM(&cfg_causes, i); 187 window_copy_add(wp, "%s", cause); 188 free(cause); 189 } 190 ARRAY_FREE(&cfg_causes); 191 } 192 cfg_finished = 1; 193 194 server_add_accept(0); 195 196 memset(&tv, 0, sizeof tv); 197 tv.tv_sec = 1; 198 evtimer_set(&server_ev_second, server_second_callback, NULL); 199 evtimer_add(&server_ev_second, &tv); 200 201 set_signals(server_signal_callback); 202 server_loop(); 203 exit(0); 204 } 205 206 /* Main server loop. */ 207 void 208 server_loop(void) 209 { 210 while (!server_should_shutdown()) { 211 event_loop(EVLOOP_ONCE); 212 213 server_window_loop(); 214 server_client_loop(); 215 216 key_bindings_clean(); 217 server_clean_dead(); 218 } 219 } 220 221 /* Check if the server should be shutting down (no more clients or sessions). */ 222 int 223 server_should_shutdown(void) 224 { 225 u_int i; 226 227 if (!options_get_number(&global_options, "exit-unattached")) { 228 if (!RB_EMPTY(&sessions)) 229 return (0); 230 } 231 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 232 if (ARRAY_ITEM(&clients, i) != NULL) 233 return (0); 234 } 235 return (1); 236 } 237 238 /* Shutdown the server by killing all clients and windows. */ 239 void 240 server_send_shutdown(void) 241 { 242 struct client *c; 243 struct session *s, *next_s; 244 u_int i; 245 246 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 247 c = ARRAY_ITEM(&clients, i); 248 if (c != NULL) { 249 if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED)) 250 server_client_lost(c); 251 else 252 server_write_client(c, MSG_SHUTDOWN, NULL, 0); 253 c->session = NULL; 254 } 255 } 256 257 s = RB_MIN(sessions, &sessions); 258 while (s != NULL) { 259 next_s = RB_NEXT(sessions, &sessions, s); 260 session_destroy(s); 261 s = next_s; 262 } 263 } 264 265 /* Free dead, unreferenced clients and sessions. */ 266 void 267 server_clean_dead(void) 268 { 269 struct session *s, *next_s; 270 struct client *c; 271 u_int i; 272 273 s = RB_MIN(sessions, &dead_sessions); 274 while (s != NULL) { 275 next_s = RB_NEXT(sessions, &dead_sessions, s); 276 if (s->references == 0) { 277 RB_REMOVE(sessions, &dead_sessions, s); 278 free(s->name); 279 free(s); 280 } 281 s = next_s; 282 } 283 284 for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) { 285 c = ARRAY_ITEM(&dead_clients, i); 286 if (c == NULL || c->references != 0) 287 continue; 288 ARRAY_SET(&dead_clients, i, NULL); 289 free(c); 290 } 291 } 292 293 /* Update socket execute permissions based on whether sessions are attached. */ 294 void 295 server_update_socket(void) 296 { 297 struct session *s; 298 static int last = -1; 299 int n, mode; 300 struct stat sb; 301 302 n = 0; 303 RB_FOREACH(s, sessions, &sessions) { 304 if (!(s->flags & SESSION_UNATTACHED)) { 305 n++; 306 break; 307 } 308 } 309 310 if (n != last) { 311 last = n; 312 313 if (stat(socket_path, &sb) != 0) 314 return; 315 mode = sb.st_mode; 316 if (n != 0) { 317 if (mode & S_IRUSR) 318 mode |= S_IXUSR; 319 if (mode & S_IRGRP) 320 mode |= S_IXGRP; 321 if (mode & S_IROTH) 322 mode |= S_IXOTH; 323 } else 324 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 325 chmod(socket_path, mode); 326 } 327 } 328 329 /* Callback for server socket. */ 330 /* ARGSUSED */ 331 void 332 server_accept_callback(int fd, short events, unused void *data) 333 { 334 struct sockaddr_storage sa; 335 socklen_t slen = sizeof sa; 336 int newfd; 337 338 server_add_accept(0); 339 if (!(events & EV_READ)) 340 return; 341 342 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 343 if (newfd == -1) { 344 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 345 return; 346 if (errno == ENFILE || errno == EMFILE) { 347 /* Delete and don't try again for 1 second. */ 348 server_add_accept(1); 349 return; 350 } 351 fatal("accept failed"); 352 } 353 if (server_shutdown) { 354 close(newfd); 355 return; 356 } 357 server_client_create(newfd); 358 } 359 360 /* 361 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 362 * event - used to backoff when running out of file descriptors. 363 */ 364 void 365 server_add_accept(int timeout) 366 { 367 struct timeval tv = { timeout, 0 }; 368 369 if (event_initialized(&server_ev_accept)) 370 event_del(&server_ev_accept); 371 372 if (timeout == 0) { 373 event_set(&server_ev_accept, 374 server_fd, EV_READ, server_accept_callback, NULL); 375 event_add(&server_ev_accept, NULL); 376 } else { 377 event_set(&server_ev_accept, 378 server_fd, EV_TIMEOUT, server_accept_callback, NULL); 379 event_add(&server_ev_accept, &tv); 380 } 381 } 382 383 /* Signal handler. */ 384 /* ARGSUSED */ 385 void 386 server_signal_callback(int sig, unused short events, unused void *data) 387 { 388 switch (sig) { 389 case SIGTERM: 390 server_shutdown = 1; 391 server_send_shutdown(); 392 break; 393 case SIGCHLD: 394 server_child_signal(); 395 break; 396 case SIGUSR1: 397 event_del(&server_ev_accept); 398 close(server_fd); 399 server_fd = server_create_socket(); 400 server_add_accept(0); 401 break; 402 } 403 } 404 405 /* Handle SIGCHLD. */ 406 void 407 server_child_signal(void) 408 { 409 int status; 410 pid_t pid; 411 412 for (;;) { 413 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 414 case -1: 415 if (errno == ECHILD) 416 return; 417 fatal("waitpid failed"); 418 case 0: 419 return; 420 } 421 if (WIFSTOPPED(status)) 422 server_child_stopped(pid, status); 423 else if (WIFEXITED(status) || WIFSIGNALED(status)) 424 server_child_exited(pid, status); 425 } 426 } 427 428 /* Handle exited children. */ 429 void 430 server_child_exited(pid_t pid, int status) 431 { 432 struct window *w; 433 struct window_pane *wp; 434 struct job *job; 435 u_int i; 436 437 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 438 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 439 continue; 440 TAILQ_FOREACH(wp, &w->panes, entry) { 441 if (wp->pid == pid) { 442 server_destroy_pane(wp); 443 break; 444 } 445 } 446 } 447 448 LIST_FOREACH(job, &all_jobs, lentry) { 449 if (pid == job->pid) { 450 job_died(job, status); /* might free job */ 451 break; 452 } 453 } 454 } 455 456 /* Handle stopped children. */ 457 void 458 server_child_stopped(pid_t pid, int status) 459 { 460 struct window *w; 461 struct window_pane *wp; 462 u_int i; 463 464 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 465 return; 466 467 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 468 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 469 continue; 470 TAILQ_FOREACH(wp, &w->panes, entry) { 471 if (wp->pid == pid) { 472 if (killpg(pid, SIGCONT) != 0) 473 kill(pid, SIGCONT); 474 } 475 } 476 } 477 } 478 479 /* Handle once-per-second timer events. */ 480 /* ARGSUSED */ 481 void 482 server_second_callback(unused int fd, unused short events, unused void *arg) 483 { 484 struct window *w; 485 struct window_pane *wp; 486 struct timeval tv; 487 u_int i; 488 489 if (options_get_number(&global_s_options, "lock-server")) 490 server_lock_server(); 491 else 492 server_lock_sessions(); 493 494 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 495 w = ARRAY_ITEM(&windows, i); 496 if (w == NULL) 497 continue; 498 499 TAILQ_FOREACH(wp, &w->panes, entry) { 500 if (wp->mode != NULL && wp->mode->timer != NULL) 501 wp->mode->timer(wp); 502 } 503 } 504 505 server_client_status_timer(); 506 507 evtimer_del(&server_ev_second); 508 memset(&tv, 0, sizeof tv); 509 tv.tv_sec = 1; 510 evtimer_add(&server_ev_second, &tv); 511 } 512 513 /* Lock the server if ALL sessions have hit the time limit. */ 514 void 515 server_lock_server(void) 516 { 517 struct session *s; 518 int timeout; 519 time_t t; 520 521 t = time(NULL); 522 RB_FOREACH(s, sessions, &sessions) { 523 if (s->flags & SESSION_UNATTACHED) 524 continue; 525 timeout = options_get_number(&s->options, "lock-after-time"); 526 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout) 527 return; /* not timed out */ 528 } 529 530 server_lock(); 531 recalculate_sizes(); 532 } 533 534 /* Lock any sessions which have timed out. */ 535 void 536 server_lock_sessions(void) 537 { 538 struct session *s; 539 int timeout; 540 time_t t; 541 542 t = time(NULL); 543 RB_FOREACH(s, sessions, &sessions) { 544 if (s->flags & SESSION_UNATTACHED) 545 continue; 546 timeout = options_get_number(&s->options, "lock-after-time"); 547 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) { 548 server_lock_session(s); 549 recalculate_sizes(); 550 } 551 } 552 } 553