1 /* $OpenBSD: server.c,v 1.77 2009/11/13 17:33:07 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_sigterm; 53 struct event server_ev_sigusr1; 54 struct event server_ev_sigchld; 55 struct event server_ev_second; 56 57 int server_create_socket(void); 58 void server_loop(void); 59 int server_should_shutdown(void); 60 void server_send_shutdown(void); 61 void server_clean_dead(void); 62 void server_accept_callback(int, short, void *); 63 void server_signal_callback(int, short, void *); 64 void server_child_signal(void); 65 void server_child_exited(pid_t, int); 66 void server_child_stopped(pid_t, int); 67 void server_second_callback(int, short, void *); 68 void server_lock_server(void); 69 void server_lock_sessions(void); 70 71 /* Create server socket. */ 72 int 73 server_create_socket(void) 74 { 75 struct sockaddr_un sa; 76 size_t size; 77 mode_t mask; 78 int fd, mode; 79 80 memset(&sa, 0, sizeof sa); 81 sa.sun_family = AF_UNIX; 82 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 83 if (size >= sizeof sa.sun_path) { 84 errno = ENAMETOOLONG; 85 fatal("socket failed"); 86 } 87 unlink(sa.sun_path); 88 89 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 90 fatal("socket failed"); 91 92 mask = umask(S_IXUSR|S_IRWXG|S_IRWXO); 93 if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) 94 fatal("bind failed"); 95 umask(mask); 96 97 if (listen(fd, 16) == -1) 98 fatal("listen failed"); 99 100 if ((mode = fcntl(fd, F_GETFL)) == -1) 101 fatal("fcntl failed"); 102 if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1) 103 fatal("fcntl failed"); 104 if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) 105 fatal("fcntl failed"); 106 107 server_update_socket(); 108 109 return (fd); 110 } 111 112 /* Fork new server. */ 113 int 114 server_start(char *path) 115 { 116 struct client *c; 117 int pair[2]; 118 char *cause, rpathbuf[MAXPATHLEN]; 119 struct timeval tv; 120 121 /* The first client is special and gets a socketpair; create it. */ 122 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 123 fatal("socketpair failed"); 124 125 switch (fork()) { 126 case -1: 127 fatal("fork failed"); 128 case 0: 129 break; 130 default: 131 close(pair[1]); 132 return (pair[0]); 133 } 134 close(pair[0]); 135 136 /* 137 * Must daemonise before loading configuration as the PID changes so 138 * $TMUX would be wrong for sessions created in the config file. 139 */ 140 if (daemon(1, 0) != 0) 141 fatal("daemon failed"); 142 143 logfile("server"); 144 log_debug("server started, pid %ld", (long) getpid()); 145 146 ARRAY_INIT(&windows); 147 ARRAY_INIT(&clients); 148 ARRAY_INIT(&dead_clients); 149 ARRAY_INIT(&sessions); 150 ARRAY_INIT(&dead_sessions); 151 TAILQ_INIT(&session_groups); 152 mode_key_init_trees(); 153 key_bindings_init(); 154 utf8_build(); 155 156 start_time = time(NULL); 157 socket_path = path; 158 159 if (realpath(socket_path, rpathbuf) == NULL) 160 strlcpy(rpathbuf, socket_path, sizeof rpathbuf); 161 log_debug("socket path %s", socket_path); 162 setproctitle("server (%s)", rpathbuf); 163 164 event_init(); 165 166 server_fd = server_create_socket(); 167 server_client_create(pair[1]); 168 169 if (access(SYSTEM_CFG, R_OK) == 0) { 170 if (load_cfg(SYSTEM_CFG, NULL, &cause) != 0) 171 goto error; 172 } else if (errno != ENOENT) { 173 xasprintf(&cause, "%s: %s", strerror(errno), SYSTEM_CFG); 174 goto error; 175 } 176 if (cfg_file != NULL && load_cfg(cfg_file, NULL, &cause) != 0) 177 goto error; 178 179 event_set(&server_ev_accept, 180 server_fd, EV_READ|EV_PERSIST, server_accept_callback, NULL); 181 event_add(&server_ev_accept, NULL); 182 183 memset(&tv, 0, sizeof tv); 184 tv.tv_sec = 1; 185 evtimer_set(&server_ev_second, server_second_callback, NULL); 186 evtimer_add(&server_ev_second, &tv); 187 188 server_signal_set(); 189 server_loop(); 190 exit(0); 191 192 error: 193 /* Write the error and shutdown the server. */ 194 c = ARRAY_FIRST(&clients); 195 196 server_write_error(c, cause); 197 server_write_client(c, MSG_EXIT, NULL, 0); 198 xfree(cause); 199 200 server_shutdown = 1; 201 202 server_signal_set(); 203 server_loop(); 204 exit(1); 205 } 206 207 /* Main server loop. */ 208 void 209 server_loop(void) 210 { 211 while (!server_should_shutdown()) { 212 event_loop(EVLOOP_ONCE); 213 214 server_window_loop(); 215 server_client_loop(); 216 217 key_bindings_clean(); 218 server_clean_dead(); 219 } 220 } 221 222 /* Check if the server should be shutting down (no more clients or windows). */ 223 int 224 server_should_shutdown(void) 225 { 226 u_int i; 227 228 for (i = 0; i < ARRAY_LENGTH(&sessions); i++) { 229 if (ARRAY_ITEM(&sessions, i) != NULL) 230 return (0); 231 } 232 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 233 if (ARRAY_ITEM(&clients, i) != NULL) 234 return (0); 235 } 236 return (1); 237 } 238 239 /* Shutdown the server by killing all clients and windows. */ 240 void 241 server_send_shutdown(void) 242 { 243 struct client *c; 244 struct session *s; 245 u_int i; 246 247 for (i = 0; i < ARRAY_LENGTH(&clients); i++) { 248 c = ARRAY_ITEM(&clients, i); 249 if (c != NULL) { 250 if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED)) 251 server_client_lost(c); 252 else 253 server_write_client(c, MSG_SHUTDOWN, NULL, 0); 254 c->session = NULL; 255 } 256 } 257 258 for (i = 0; i < ARRAY_LENGTH(&sessions); i++) { 259 if ((s = ARRAY_ITEM(&sessions, i)) != NULL) 260 session_destroy(s); 261 } 262 } 263 264 /* Free dead, unreferenced clients and sessions. */ 265 void 266 server_clean_dead(void) 267 { 268 struct session *s; 269 struct client *c; 270 u_int i; 271 272 for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) { 273 s = ARRAY_ITEM(&dead_sessions, i); 274 if (s == NULL || s->references != 0) 275 continue; 276 ARRAY_SET(&dead_sessions, i, NULL); 277 xfree(s); 278 } 279 280 for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) { 281 c = ARRAY_ITEM(&dead_clients, i); 282 if (c == NULL || c->references != 0) 283 continue; 284 ARRAY_SET(&dead_clients, i, NULL); 285 xfree(c); 286 } 287 } 288 289 /* Update socket execute permissions based on whether sessions are attached. */ 290 void 291 server_update_socket(void) 292 { 293 struct session *s; 294 u_int i; 295 static int last = -1; 296 int n; 297 298 n = 0; 299 for (i = 0; i < ARRAY_LENGTH(&sessions); i++) { 300 s = ARRAY_ITEM(&sessions, i); 301 if (s != NULL && !(s->flags & SESSION_UNATTACHED)) { 302 n++; 303 break; 304 } 305 } 306 307 if (n != last) { 308 last = n; 309 if (n != 0) 310 chmod(socket_path, S_IRWXU); 311 else 312 chmod(socket_path, S_IRUSR|S_IWUSR); 313 } 314 } 315 316 /* Callback for server socket. */ 317 void 318 server_accept_callback(int fd, short events, unused void *data) 319 { 320 struct sockaddr_storage sa; 321 socklen_t slen = sizeof sa; 322 int newfd; 323 324 if (!(events & EV_READ)) 325 return; 326 327 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 328 if (newfd == -1) { 329 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 330 return; 331 fatal("accept failed"); 332 } 333 if (server_shutdown) { 334 close(newfd); 335 return; 336 } 337 server_client_create(newfd); 338 } 339 340 /* Set up server signal handling. */ 341 void 342 server_signal_set(void) 343 { 344 struct sigaction sigact; 345 346 memset(&sigact, 0, sizeof sigact); 347 sigemptyset(&sigact.sa_mask); 348 sigact.sa_flags = SA_RESTART; 349 sigact.sa_handler = SIG_IGN; 350 if (sigaction(SIGINT, &sigact, NULL) != 0) 351 fatal("sigaction failed"); 352 if (sigaction(SIGPIPE, &sigact, NULL) != 0) 353 fatal("sigaction failed"); 354 if (sigaction(SIGUSR2, &sigact, NULL) != 0) 355 fatal("sigaction failed"); 356 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 357 fatal("sigaction failed"); 358 359 signal_set(&server_ev_sigchld, SIGCHLD, server_signal_callback, NULL); 360 signal_add(&server_ev_sigchld, NULL); 361 signal_set(&server_ev_sigterm, SIGTERM, server_signal_callback, NULL); 362 signal_add(&server_ev_sigterm, NULL); 363 signal_set(&server_ev_sigusr1, SIGUSR1, server_signal_callback, NULL); 364 signal_add(&server_ev_sigusr1, NULL); 365 } 366 367 /* Destroy server signal events. */ 368 void 369 server_signal_clear(void) 370 { 371 struct sigaction sigact; 372 373 memset(&sigact, 0, sizeof sigact); 374 sigemptyset(&sigact.sa_mask); 375 sigact.sa_flags = SA_RESTART; 376 sigact.sa_handler = SIG_DFL; 377 if (sigaction(SIGINT, &sigact, NULL) != 0) 378 fatal("sigaction failed"); 379 if (sigaction(SIGPIPE, &sigact, NULL) != 0) 380 fatal("sigaction failed"); 381 if (sigaction(SIGUSR2, &sigact, NULL) != 0) 382 fatal("sigaction failed"); 383 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 384 fatal("sigaction failed"); 385 386 signal_del(&server_ev_sigchld); 387 signal_del(&server_ev_sigterm); 388 signal_del(&server_ev_sigusr1); 389 } 390 391 /* Signal handler. */ 392 void 393 server_signal_callback(int sig, unused short events, unused void *data) 394 { 395 switch (sig) { 396 case SIGTERM: 397 server_shutdown = 1; 398 server_send_shutdown(); 399 break; 400 case SIGCHLD: 401 server_child_signal(); 402 break; 403 case SIGUSR1: 404 event_del(&server_ev_accept); 405 close(server_fd); 406 server_fd = server_create_socket(); 407 event_set(&server_ev_accept, server_fd, 408 EV_READ|EV_PERSIST, server_accept_callback, NULL); 409 event_add(&server_ev_accept, NULL); 410 break; 411 } 412 } 413 414 /* Handle SIGCHLD. */ 415 void 416 server_child_signal(void) 417 { 418 int status; 419 pid_t pid; 420 421 for (;;) { 422 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 423 case -1: 424 if (errno == ECHILD) 425 return; 426 fatal("waitpid failed"); 427 case 0: 428 return; 429 } 430 if (WIFSTOPPED(status)) 431 server_child_stopped(pid, status); 432 else if (WIFEXITED(status)) 433 server_child_exited(pid, status); 434 } 435 } 436 437 /* Handle exited children. */ 438 void 439 server_child_exited(pid_t pid, int status) 440 { 441 struct window *w; 442 struct window_pane *wp; 443 struct job *job; 444 u_int i; 445 446 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 447 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 448 continue; 449 TAILQ_FOREACH(wp, &w->panes, entry) { 450 if (wp->pid == pid) { 451 server_destroy_pane(wp); 452 break; 453 } 454 } 455 } 456 457 SLIST_FOREACH(job, &all_jobs, lentry) { 458 if (pid == job->pid) { 459 job_died(job, status); /* might free job */ 460 break; 461 } 462 } 463 } 464 465 /* Handle stopped children. */ 466 void 467 server_child_stopped(pid_t pid, int status) 468 { 469 struct window *w; 470 struct window_pane *wp; 471 u_int i; 472 473 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 474 return; 475 476 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 477 if ((w = ARRAY_ITEM(&windows, i)) == NULL) 478 continue; 479 TAILQ_FOREACH(wp, &w->panes, entry) { 480 if (wp->pid == pid) { 481 if (killpg(pid, SIGCONT) != 0) 482 kill(pid, SIGCONT); 483 } 484 } 485 } 486 } 487 488 /* Handle once-per-second timer events. */ 489 void 490 server_second_callback(unused int fd, unused short events, unused void *arg) 491 { 492 struct window *w; 493 struct window_pane *wp; 494 struct timeval tv; 495 u_int i; 496 497 if (options_get_number(&global_s_options, "lock-server")) 498 server_lock_server(); 499 else 500 server_lock_sessions(); 501 502 for (i = 0; i < ARRAY_LENGTH(&windows); i++) { 503 w = ARRAY_ITEM(&windows, i); 504 if (w == NULL) 505 continue; 506 507 TAILQ_FOREACH(wp, &w->panes, entry) { 508 if (wp->mode != NULL && wp->mode->timer != NULL) 509 wp->mode->timer(wp); 510 } 511 } 512 513 server_client_status_timer(); 514 515 evtimer_del(&server_ev_second); 516 memset(&tv, 0, sizeof tv); 517 tv.tv_sec = 1; 518 evtimer_add(&server_ev_second, &tv); 519 } 520 521 /* Lock the server if ALL sessions have hit the time limit. */ 522 void 523 server_lock_server(void) 524 { 525 struct session *s; 526 u_int i; 527 int timeout; 528 time_t t; 529 530 t = time(NULL); 531 for (i = 0; i < ARRAY_LENGTH(&sessions); i++) { 532 if ((s = ARRAY_ITEM(&sessions, i)) == NULL) 533 continue; 534 535 if (s->flags & SESSION_UNATTACHED) { 536 if (gettimeofday(&s->activity_time, NULL) != 0) 537 fatal("gettimeofday failed"); 538 continue; 539 } 540 541 timeout = options_get_number(&s->options, "lock-after-time"); 542 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout) 543 return; /* not timed out */ 544 } 545 546 server_lock(); 547 recalculate_sizes(); 548 } 549 550 /* Lock any sessions which have timed out. */ 551 void 552 server_lock_sessions(void) 553 { 554 struct session *s; 555 u_int i; 556 int timeout; 557 time_t t; 558 559 t = time(NULL); 560 for (i = 0; i < ARRAY_LENGTH(&sessions); i++) { 561 if ((s = ARRAY_ITEM(&sessions, i)) == NULL) 562 continue; 563 564 if (s->flags & SESSION_UNATTACHED) { 565 if (gettimeofday(&s->activity_time, NULL) != 0) 566 fatal("gettimeofday failed"); 567 continue; 568 } 569 570 timeout = options_get_number(&s->options, "lock-after-time"); 571 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) { 572 server_lock_session(s); 573 recalculate_sizes(); 574 } 575 } 576 } 577