1 /* $OpenBSD: server.c,v 1.138 2015/08/30 22:19:07 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 <termios.h> 35 #include <time.h> 36 #include <unistd.h> 37 38 #include "tmux.h" 39 40 /* 41 * Main server functions. 42 */ 43 44 struct clients clients; 45 46 int server_fd; 47 int server_shutdown; 48 struct event server_ev_accept; 49 50 struct session *marked_session; 51 struct winlink *marked_winlink; 52 struct window *marked_window; 53 struct window_pane *marked_window_pane; 54 struct layout_cell *marked_layout_cell; 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_accept_callback(int, short, void *); 61 void server_signal_callback(int, short, void *); 62 void server_child_signal(void); 63 void server_child_exited(pid_t, int); 64 void server_child_stopped(pid_t, int); 65 66 /* Set marked pane. */ 67 void 68 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 69 { 70 marked_session = s; 71 marked_winlink = wl; 72 marked_window = wl->window; 73 marked_window_pane = wp; 74 marked_layout_cell = wp->layout_cell; 75 } 76 77 /* Clear marked pane. */ 78 void 79 server_clear_marked(void) 80 { 81 marked_session = NULL; 82 marked_winlink = NULL; 83 marked_window = NULL; 84 marked_window_pane = NULL; 85 marked_layout_cell = NULL; 86 } 87 88 /* Is this the marked pane? */ 89 int 90 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 91 { 92 if (s == NULL || wl == NULL || wp == NULL) 93 return (0); 94 if (marked_session != s || marked_winlink != wl) 95 return (0); 96 if (marked_window_pane != wp) 97 return (0); 98 return (server_check_marked()); 99 } 100 101 /* Check if the marked pane is still valid. */ 102 int 103 server_check_marked(void) 104 { 105 struct winlink *wl; 106 107 if (marked_window_pane == NULL) 108 return (0); 109 if (marked_layout_cell != marked_window_pane->layout_cell) 110 return (0); 111 112 if (!session_alive(marked_session)) 113 return (0); 114 RB_FOREACH(wl, winlinks, &marked_session->windows) { 115 if (wl->window == marked_window && wl == marked_winlink) 116 break; 117 } 118 if (wl == NULL) 119 return (0); 120 121 if (!window_has_pane(marked_window, marked_window_pane)) 122 return (0); 123 return (window_pane_visible(marked_window_pane)); 124 } 125 126 /* Create server socket. */ 127 int 128 server_create_socket(void) 129 { 130 struct sockaddr_un sa; 131 size_t size; 132 mode_t mask; 133 int fd; 134 135 memset(&sa, 0, sizeof sa); 136 sa.sun_family = AF_UNIX; 137 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 138 if (size >= sizeof sa.sun_path) { 139 errno = ENAMETOOLONG; 140 return (-1); 141 } 142 unlink(sa.sun_path); 143 144 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 145 return (-1); 146 147 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 148 if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) 149 return (-1); 150 umask(mask); 151 152 if (listen(fd, 16) == -1) 153 return (-1); 154 setblocking(fd, 0); 155 156 return (fd); 157 } 158 159 /* Fork new server. */ 160 int 161 server_start(struct event_base *base, int lockfd, char *lockfile) 162 { 163 int pair[2]; 164 char *cause; 165 166 /* The first client is special and gets a socketpair; create it. */ 167 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 168 fatal("socketpair failed"); 169 log_debug("starting server"); 170 171 switch (fork()) { 172 case -1: 173 fatal("fork failed"); 174 case 0: 175 break; 176 default: 177 close(pair[1]); 178 return (pair[0]); 179 } 180 close(pair[0]); 181 182 /* 183 * Must daemonise before loading configuration as the PID changes so 184 * $TMUX would be wrong for sessions created in the config file. 185 */ 186 if (daemon(1, 0) != 0) 187 fatal("daemon failed"); 188 189 /* event_init() was called in our parent, need to reinit. */ 190 clear_signals(0); 191 if (event_reinit(base) != 0) 192 fatal("event_reinit failed"); 193 194 logfile("server"); 195 log_debug("server started, pid %ld", (long) getpid()); 196 197 RB_INIT(&windows); 198 RB_INIT(&all_window_panes); 199 TAILQ_INIT(&clients); 200 RB_INIT(&sessions); 201 TAILQ_INIT(&session_groups); 202 mode_key_init_trees(); 203 key_bindings_init(); 204 utf8_build(); 205 206 start_time = time(NULL); 207 log_debug("socket path %s", socket_path); 208 setproctitle("server (%s)", socket_path); 209 210 server_fd = server_create_socket(); 211 if (server_fd == -1) 212 fatal("couldn't create socket"); 213 server_update_socket(); 214 server_client_create(pair[1]); 215 216 unlink(lockfile); 217 free(lockfile); 218 close(lockfd); 219 220 cfg_cmd_q = cmdq_new(NULL); 221 cfg_cmd_q->emptyfn = cfg_default_done; 222 cfg_finished = 0; 223 cfg_references = 1; 224 cfg_client = TAILQ_FIRST(&clients); 225 if (cfg_client != NULL) 226 cfg_client->references++; 227 228 if (access(TMUX_CONF, R_OK) == 0) { 229 if (load_cfg(TMUX_CONF, cfg_cmd_q, &cause) == -1) 230 cfg_add_cause("%s: %s", TMUX_CONF, cause); 231 } else if (errno != ENOENT) 232 cfg_add_cause("%s: %s", TMUX_CONF, strerror(errno)); 233 if (cfg_file != NULL) { 234 if (load_cfg(cfg_file, cfg_cmd_q, &cause) == -1) 235 cfg_add_cause("%s: %s", cfg_file, cause); 236 } 237 cmdq_continue(cfg_cmd_q); 238 status_prompt_load_history(); 239 240 server_add_accept(0); 241 242 set_signals(server_signal_callback); 243 server_loop(); 244 status_prompt_save_history(); 245 exit(0); 246 } 247 248 /* Main server loop. */ 249 void 250 server_loop(void) 251 { 252 while (!server_should_shutdown()) { 253 log_debug("event dispatch enter"); 254 event_loop(EVLOOP_ONCE); 255 log_debug("event dispatch exit"); 256 257 server_client_loop(); 258 } 259 } 260 261 /* Check if the server should exit (no more clients or sessions). */ 262 int 263 server_should_shutdown(void) 264 { 265 struct client *c; 266 267 if (!options_get_number(&global_options, "exit-unattached")) { 268 if (!RB_EMPTY(&sessions)) 269 return (0); 270 } 271 272 TAILQ_FOREACH(c, &clients, entry) { 273 if (c->session != NULL) 274 return (0); 275 } 276 277 /* 278 * No attached clients therefore want to exit - flush any waiting 279 * clients but don't actually exit until they've gone. 280 */ 281 cmd_wait_for_flush(); 282 if (!TAILQ_EMPTY(&clients)) 283 return (0); 284 285 return (1); 286 } 287 288 /* Shutdown the server by killing all clients and windows. */ 289 void 290 server_send_shutdown(void) 291 { 292 struct client *c, *c1; 293 struct session *s, *s1; 294 295 cmd_wait_for_flush(); 296 297 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 298 if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED)) 299 server_client_lost(c); 300 else 301 server_write_client(c, MSG_SHUTDOWN, NULL, 0); 302 c->session = NULL; 303 } 304 305 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 306 session_destroy(s); 307 } 308 309 /* Update socket execute permissions based on whether sessions are attached. */ 310 void 311 server_update_socket(void) 312 { 313 struct session *s; 314 static int last = -1; 315 int n, mode; 316 struct stat sb; 317 318 n = 0; 319 RB_FOREACH(s, sessions, &sessions) { 320 if (!(s->flags & SESSION_UNATTACHED)) { 321 n++; 322 break; 323 } 324 } 325 326 if (n != last) { 327 last = n; 328 329 if (stat(socket_path, &sb) != 0) 330 return; 331 mode = sb.st_mode; 332 if (n != 0) { 333 if (mode & S_IRUSR) 334 mode |= S_IXUSR; 335 if (mode & S_IRGRP) 336 mode |= S_IXGRP; 337 if (mode & S_IROTH) 338 mode |= S_IXOTH; 339 } else 340 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 341 chmod(socket_path, mode); 342 } 343 } 344 345 /* Callback for server socket. */ 346 void 347 server_accept_callback(int fd, short events, unused void *data) 348 { 349 struct sockaddr_storage sa; 350 socklen_t slen = sizeof sa; 351 int newfd; 352 353 server_add_accept(0); 354 if (!(events & EV_READ)) 355 return; 356 357 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 358 if (newfd == -1) { 359 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 360 return; 361 if (errno == ENFILE || errno == EMFILE) { 362 /* Delete and don't try again for 1 second. */ 363 server_add_accept(1); 364 return; 365 } 366 fatal("accept failed"); 367 } 368 if (server_shutdown) { 369 close(newfd); 370 return; 371 } 372 server_client_create(newfd); 373 } 374 375 /* 376 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 377 * event - used to backoff when running out of file descriptors. 378 */ 379 void 380 server_add_accept(int timeout) 381 { 382 struct timeval tv = { timeout, 0 }; 383 384 if (event_initialized(&server_ev_accept)) 385 event_del(&server_ev_accept); 386 387 if (timeout == 0) { 388 event_set(&server_ev_accept, 389 server_fd, EV_READ, server_accept_callback, NULL); 390 event_add(&server_ev_accept, NULL); 391 } else { 392 event_set(&server_ev_accept, 393 server_fd, EV_TIMEOUT, server_accept_callback, NULL); 394 event_add(&server_ev_accept, &tv); 395 } 396 } 397 398 /* Signal handler. */ 399 void 400 server_signal_callback(int sig, unused short events, unused void *data) 401 { 402 int fd; 403 404 switch (sig) { 405 case SIGTERM: 406 server_shutdown = 1; 407 server_send_shutdown(); 408 break; 409 case SIGCHLD: 410 server_child_signal(); 411 break; 412 case SIGUSR1: 413 event_del(&server_ev_accept); 414 fd = server_create_socket(); 415 if (fd != -1) { 416 close(server_fd); 417 server_fd = fd; 418 server_update_socket(); 419 } 420 server_add_accept(0); 421 break; 422 } 423 } 424 425 /* Handle SIGCHLD. */ 426 void 427 server_child_signal(void) 428 { 429 int status; 430 pid_t pid; 431 432 for (;;) { 433 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 434 case -1: 435 if (errno == ECHILD) 436 return; 437 fatal("waitpid failed"); 438 case 0: 439 return; 440 } 441 if (WIFSTOPPED(status)) 442 server_child_stopped(pid, status); 443 else if (WIFEXITED(status) || WIFSIGNALED(status)) 444 server_child_exited(pid, status); 445 } 446 } 447 448 /* Handle exited children. */ 449 void 450 server_child_exited(pid_t pid, int status) 451 { 452 struct window *w, *w1; 453 struct window_pane *wp; 454 struct job *job; 455 456 RB_FOREACH_SAFE(w, windows, &windows, w1) { 457 TAILQ_FOREACH(wp, &w->panes, entry) { 458 if (wp->pid == pid) { 459 wp->status = status; 460 server_destroy_pane(wp); 461 break; 462 } 463 } 464 } 465 466 LIST_FOREACH(job, &all_jobs, lentry) { 467 if (pid == job->pid) { 468 job_died(job, status); /* might free job */ 469 break; 470 } 471 } 472 } 473 474 /* Handle stopped children. */ 475 void 476 server_child_stopped(pid_t pid, int status) 477 { 478 struct window *w; 479 struct window_pane *wp; 480 481 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 482 return; 483 484 RB_FOREACH(w, windows, &windows) { 485 TAILQ_FOREACH(wp, &w->panes, entry) { 486 if (wp->pid == pid) { 487 if (killpg(pid, SIGCONT) != 0) 488 kill(pid, SIGCONT); 489 } 490 } 491 } 492 } 493