1 /* $OpenBSD: server.c,v 1.109 2013/03/24 09:54:10 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 int pair[2]; 110 struct timeval tv; 111 char *cause; 112 113 /* The first client is special and gets a socketpair; create it. */ 114 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 115 fatal("socketpair failed"); 116 117 switch (fork()) { 118 case -1: 119 fatal("fork failed"); 120 case 0: 121 break; 122 default: 123 close(pair[1]); 124 return (pair[0]); 125 } 126 close(pair[0]); 127 128 /* 129 * Must daemonise before loading configuration as the PID changes so 130 * $TMUX would be wrong for sessions created in the config file. 131 */ 132 if (daemon(1, 0) != 0) 133 fatal("daemon failed"); 134 135 /* event_init() was called in our parent, need to reinit. */ 136 if (event_reinit(ev_base) != 0) 137 fatal("event_reinit failed"); 138 clear_signals(0); 139 140 logfile("server"); 141 log_debug("server started, pid %ld", (long) getpid()); 142 143 ARRAY_INIT(&windows); 144 RB_INIT(&all_window_panes); 145 ARRAY_INIT(&clients); 146 ARRAY_INIT(&dead_clients); 147 RB_INIT(&sessions); 148 RB_INIT(&dead_sessions); 149 TAILQ_INIT(&session_groups); 150 ARRAY_INIT(&global_buffers); 151 mode_key_init_trees(); 152 key_bindings_init(); 153 utf8_build(); 154 155 start_time = time(NULL); 156 log_debug("socket path %s", socket_path); 157 setproctitle("server (%s)", socket_path); 158 159 server_fd = server_create_socket(); 160 server_client_create(pair[1]); 161 162 unlink(lockfile); 163 free(lockfile); 164 close(lockfd); 165 166 cfg_cmd_q = cmdq_new(NULL); 167 cfg_cmd_q->emptyfn = cfg_default_done; 168 cfg_finished = 0; 169 cfg_references = 1; 170 ARRAY_INIT(&cfg_causes); 171 172 if (access(SYSTEM_CFG, R_OK) == 0) { 173 if (load_cfg(SYSTEM_CFG, cfg_cmd_q, &cause) == -1) { 174 xasprintf(&cause, "%s: %s", SYSTEM_CFG, cause); 175 ARRAY_ADD(&cfg_causes, cause); 176 } 177 } else if (errno != ENOENT) { 178 xasprintf(&cause, "%s: %s", SYSTEM_CFG, strerror(errno)); 179 ARRAY_ADD(&cfg_causes, cause); 180 } 181 if (cfg_file != NULL) { 182 if (load_cfg(cfg_file, cfg_cmd_q, &cause) == -1) { 183 xasprintf(&cause, "%s: %s", cfg_file, cause); 184 ARRAY_ADD(&cfg_causes, cause); 185 } 186 } 187 cmdq_continue(cfg_cmd_q); 188 189 server_add_accept(0); 190 191 memset(&tv, 0, sizeof tv); 192 tv.tv_sec = 1; 193 evtimer_set(&server_ev_second, server_second_callback, NULL); 194 evtimer_add(&server_ev_second, &tv); 195 196 set_signals(server_signal_callback); 197 server_loop(); 198 exit(0); 199 } 200 201 /* Main server loop. */ 202 void 203 server_loop(void) 204 { 205 while (!server_should_shutdown()) { 206 event_loop(EVLOOP_ONCE); 207 208 server_window_loop(); 209 server_client_loop(); 210 211 key_bindings_clean(); 212 server_clean_dead(); 213 } 214 } 215 216 /* Check if the server should be shutting down (no more clients or sessions). */ 217 int 218 server_should_shutdown(void) 219 { 220 u_int i; 221 222 if (!options_get_number(&global_options, "exit-unattached")) { 223 if (!RB_EMPTY(&sessions)) 224 return (0); 225 } 226 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 227 if (ARRAY_ITEM(&clients, i) != NULL) 228 return (0); 229 } 230 return (1); 231 } 232 233 /* Shutdown the server by killing all clients and windows. */ 234 void 235 server_send_shutdown(void) 236 { 237 struct client *c; 238 struct session *s, *next_s; 239 u_int i; 240 241 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 242 c = ARRAY_ITEM(&clients, i); 243 if (c != NULL) { 244 if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED)) 245 server_client_lost(c); 246 else 247 server_write_client(c, MSG_SHUTDOWN, NULL, 0); 248 c->session = NULL; 249 } 250 } 251 252 s = RB_MIN(sessions, &sessions); 253 while (s != NULL) { 254 next_s = RB_NEXT(sessions, &sessions, s); 255 session_destroy(s); 256 s = next_s; 257 } 258 } 259 260 /* Free dead, unreferenced clients and sessions. */ 261 void 262 server_clean_dead(void) 263 { 264 struct session *s, *next_s; 265 struct client *c; 266 u_int i; 267 268 s = RB_MIN(sessions, &dead_sessions); 269 while (s != NULL) { 270 next_s = RB_NEXT(sessions, &dead_sessions, s); 271 if (s->references == 0) { 272 RB_REMOVE(sessions, &dead_sessions, s); 273 free(s->name); 274 free(s); 275 } 276 s = next_s; 277 } 278 279 for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) { 280 c = ARRAY_ITEM(&dead_clients, i); 281 if (c == NULL || c->references != 0) 282 continue; 283 ARRAY_SET(&dead_clients, i, NULL); 284 free(c); 285 } 286 } 287 288 /* Update socket execute permissions based on whether sessions are attached. */ 289 void 290 server_update_socket(void) 291 { 292 struct session *s; 293 static int last = -1; 294 int n, mode; 295 struct stat sb; 296 297 n = 0; 298 RB_FOREACH(s, sessions, &sessions) { 299 if (!(s->flags & SESSION_UNATTACHED)) { 300 n++; 301 break; 302 } 303 } 304 305 if (n != last) { 306 last = n; 307 308 if (stat(socket_path, &sb) != 0) 309 return; 310 mode = sb.st_mode; 311 if (n != 0) { 312 if (mode & S_IRUSR) 313 mode |= S_IXUSR; 314 if (mode & S_IRGRP) 315 mode |= S_IXGRP; 316 if (mode & S_IROTH) 317 mode |= S_IXOTH; 318 } else 319 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 320 chmod(socket_path, mode); 321 } 322 } 323 324 /* Callback for server socket. */ 325 void 326 server_accept_callback(int fd, short events, unused void *data) 327 { 328 struct sockaddr_storage sa; 329 socklen_t slen = sizeof sa; 330 int newfd; 331 332 server_add_accept(0); 333 if (!(events & EV_READ)) 334 return; 335 336 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 337 if (newfd == -1) { 338 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 339 return; 340 if (errno == ENFILE || errno == EMFILE) { 341 /* Delete and don't try again for 1 second. */ 342 server_add_accept(1); 343 return; 344 } 345 fatal("accept failed"); 346 } 347 if (server_shutdown) { 348 close(newfd); 349 return; 350 } 351 server_client_create(newfd); 352 } 353 354 /* 355 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 356 * event - used to backoff when running out of file descriptors. 357 */ 358 void 359 server_add_accept(int timeout) 360 { 361 struct timeval tv = { timeout, 0 }; 362 363 if (event_initialized(&server_ev_accept)) 364 event_del(&server_ev_accept); 365 366 if (timeout == 0) { 367 event_set(&server_ev_accept, 368 server_fd, EV_READ, server_accept_callback, NULL); 369 event_add(&server_ev_accept, NULL); 370 } else { 371 event_set(&server_ev_accept, 372 server_fd, EV_TIMEOUT, server_accept_callback, NULL); 373 event_add(&server_ev_accept, &tv); 374 } 375 } 376 377 /* Signal handler. */ 378 void 379 server_signal_callback(int sig, unused short events, unused void *data) 380 { 381 switch (sig) { 382 case SIGTERM: 383 server_shutdown = 1; 384 server_send_shutdown(); 385 break; 386 case SIGCHLD: 387 server_child_signal(); 388 break; 389 case SIGUSR1: 390 event_del(&server_ev_accept); 391 close(server_fd); 392 server_fd = server_create_socket(); 393 server_add_accept(0); 394 break; 395 } 396 } 397 398 /* Handle SIGCHLD. */ 399 void 400 server_child_signal(void) 401 { 402 int status; 403 pid_t pid; 404 405 for (;;) { 406 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 407 case -1: 408 if (errno == ECHILD) 409 return; 410 fatal("waitpid failed"); 411 case 0: 412 return; 413 } 414 if (WIFSTOPPED(status)) 415 server_child_stopped(pid, status); 416 else if (WIFEXITED(status) || WIFSIGNALED(status)) 417 server_child_exited(pid, status); 418 } 419 } 420 421 /* Handle exited children. */ 422 void 423 server_child_exited(pid_t pid, int status) 424 { 425 struct window *w; 426 struct window_pane *wp; 427 struct job *job; 428 u_int i; 429 430 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 431 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 432 continue; 433 TAILQ_FOREACH(wp, &w->panes, entry) { 434 if (wp->pid == pid) { 435 server_destroy_pane(wp); 436 break; 437 } 438 } 439 } 440 441 LIST_FOREACH(job, &all_jobs, lentry) { 442 if (pid == job->pid) { 443 job_died(job, status); /* might free job */ 444 break; 445 } 446 } 447 } 448 449 /* Handle stopped children. */ 450 void 451 server_child_stopped(pid_t pid, int status) 452 { 453 struct window *w; 454 struct window_pane *wp; 455 u_int i; 456 457 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 458 return; 459 460 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 461 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 462 continue; 463 TAILQ_FOREACH(wp, &w->panes, entry) { 464 if (wp->pid == pid) { 465 if (killpg(pid, SIGCONT) != 0) 466 kill(pid, SIGCONT); 467 } 468 } 469 } 470 } 471 472 /* Handle once-per-second timer events. */ 473 void 474 server_second_callback(unused int fd, unused short events, unused void *arg) 475 { 476 struct window *w; 477 struct window_pane *wp; 478 struct timeval tv; 479 u_int i; 480 481 if (options_get_number(&global_s_options, "lock-server")) 482 server_lock_server(); 483 else 484 server_lock_sessions(); 485 486 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 487 w = ARRAY_ITEM(&windows, i); 488 if (w == NULL) 489 continue; 490 491 TAILQ_FOREACH(wp, &w->panes, entry) { 492 if (wp->mode != NULL && wp->mode->timer != NULL) 493 wp->mode->timer(wp); 494 } 495 } 496 497 server_client_status_timer(); 498 499 evtimer_del(&server_ev_second); 500 memset(&tv, 0, sizeof tv); 501 tv.tv_sec = 1; 502 evtimer_add(&server_ev_second, &tv); 503 } 504 505 /* Lock the server if ALL sessions have hit the time limit. */ 506 void 507 server_lock_server(void) 508 { 509 struct session *s; 510 int timeout; 511 time_t t; 512 513 t = time(NULL); 514 RB_FOREACH(s, sessions, &sessions) { 515 if (s->flags & SESSION_UNATTACHED) 516 continue; 517 timeout = options_get_number(&s->options, "lock-after-time"); 518 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout) 519 return; /* not timed out */ 520 } 521 522 server_lock(); 523 recalculate_sizes(); 524 } 525 526 /* Lock any sessions which have timed out. */ 527 void 528 server_lock_sessions(void) 529 { 530 struct session *s; 531 int timeout; 532 time_t t; 533 534 t = time(NULL); 535 RB_FOREACH(s, sessions, &sessions) { 536 if (s->flags & SESSION_UNATTACHED) 537 continue; 538 timeout = options_get_number(&s->options, "lock-after-time"); 539 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) { 540 server_lock_session(s); 541 recalculate_sizes(); 542 } 543 } 544 } 545