1 /* $OpenBSD: server.c,v 1.208 2025/01/01 15:17:36 nicm Exp $ */ 2 3 /* 4 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com> 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 struct tmuxproc *server_proc; 47 static int server_fd = -1; 48 static uint64_t server_client_flags; 49 static int server_exit; 50 static struct event server_ev_accept; 51 static struct event server_ev_tidy; 52 53 struct cmd_find_state marked_pane; 54 55 static u_int message_next; 56 struct message_list message_log; 57 58 time_t current_time; 59 60 static int server_loop(void); 61 static void server_send_exit(void); 62 static void server_accept(int, short, void *); 63 static void server_signal(int); 64 static void server_child_signal(void); 65 static void server_child_exited(pid_t, int); 66 static void server_child_stopped(pid_t, int); 67 68 /* Set marked pane. */ 69 void 70 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 71 { 72 cmd_find_clear_state(&marked_pane, 0); 73 marked_pane.s = s; 74 marked_pane.wl = wl; 75 marked_pane.w = wl->window; 76 marked_pane.wp = wp; 77 } 78 79 /* Clear marked pane. */ 80 void 81 server_clear_marked(void) 82 { 83 cmd_find_clear_state(&marked_pane, 0); 84 } 85 86 /* Is this the marked pane? */ 87 int 88 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 89 { 90 if (s == NULL || wl == NULL || wp == NULL) 91 return (0); 92 if (marked_pane.s != s || marked_pane.wl != wl) 93 return (0); 94 if (marked_pane.wp != wp) 95 return (0); 96 return (server_check_marked()); 97 } 98 99 /* Check if the marked pane is still valid. */ 100 int 101 server_check_marked(void) 102 { 103 return (cmd_find_valid_state(&marked_pane)); 104 } 105 106 /* Create server socket. */ 107 int 108 server_create_socket(uint64_t flags, char **cause) 109 { 110 struct sockaddr_un sa; 111 size_t size; 112 mode_t mask; 113 int fd, saved_errno; 114 115 memset(&sa, 0, sizeof sa); 116 sa.sun_family = AF_UNIX; 117 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 118 if (size >= sizeof sa.sun_path) { 119 errno = ENAMETOOLONG; 120 goto fail; 121 } 122 unlink(sa.sun_path); 123 124 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 125 goto fail; 126 127 if (flags & CLIENT_DEFAULTSOCKET) 128 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 129 else 130 mask = umask(S_IXUSR|S_IRWXG|S_IRWXO); 131 if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 132 saved_errno = errno; 133 close(fd); 134 errno = saved_errno; 135 goto fail; 136 } 137 umask(mask); 138 139 if (listen(fd, 128) == -1) { 140 saved_errno = errno; 141 close(fd); 142 errno = saved_errno; 143 goto fail; 144 } 145 setblocking(fd, 0); 146 147 return (fd); 148 149 fail: 150 if (cause != NULL) { 151 xasprintf(cause, "error creating %s (%s)", socket_path, 152 strerror(errno)); 153 } 154 return (-1); 155 } 156 157 /* Tidy up every hour. */ 158 static void 159 server_tidy_event(__unused int fd, __unused short events, __unused void *data) 160 { 161 struct timeval tv = { .tv_sec = 3600 }; 162 uint64_t t = get_timer(); 163 164 format_tidy_jobs(); 165 166 log_debug("%s: took %llu milliseconds", __func__, 167 (unsigned long long)(get_timer() - t)); 168 evtimer_add(&server_ev_tidy, &tv); 169 } 170 171 /* Fork new server. */ 172 int 173 server_start(struct tmuxproc *client, uint64_t flags, struct event_base *base, 174 int lockfd, char *lockfile) 175 { 176 int fd; 177 sigset_t set, oldset; 178 struct client *c = NULL; 179 char *cause = NULL; 180 struct timeval tv = { .tv_sec = 3600 }; 181 182 sigfillset(&set); 183 sigprocmask(SIG_BLOCK, &set, &oldset); 184 185 if (~flags & CLIENT_NOFORK) { 186 if (proc_fork_and_daemon(&fd) != 0) { 187 sigprocmask(SIG_SETMASK, &oldset, NULL); 188 return (fd); 189 } 190 } 191 proc_clear_signals(client, 0); 192 server_client_flags = flags; 193 194 if (event_reinit(base) != 0) 195 fatalx("event_reinit failed"); 196 server_proc = proc_start("server"); 197 198 proc_set_signals(server_proc, server_signal); 199 sigprocmask(SIG_SETMASK, &oldset, NULL); 200 201 if (log_get_level() > 1) 202 tty_create_log(); 203 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 204 "tty ps", NULL) != 0) 205 fatal("pledge failed"); 206 207 input_key_build(); 208 utf8_update_width_cache(); 209 RB_INIT(&windows); 210 RB_INIT(&all_window_panes); 211 TAILQ_INIT(&clients); 212 RB_INIT(&sessions); 213 key_bindings_init(); 214 TAILQ_INIT(&message_log); 215 gettimeofday(&start_time, NULL); 216 217 server_fd = server_create_socket(flags, &cause); 218 if (server_fd != -1) 219 server_update_socket(); 220 if (~flags & CLIENT_NOFORK) 221 c = server_client_create(fd); 222 else 223 options_set_number(global_options, "exit-empty", 0); 224 225 if (lockfd >= 0) { 226 unlink(lockfile); 227 free(lockfile); 228 close(lockfd); 229 } 230 231 if (cause != NULL) { 232 if (c != NULL) { 233 c->exit_message = cause; 234 c->flags |= CLIENT_EXIT; 235 } else { 236 fprintf(stderr, "%s\n", cause); 237 exit(1); 238 } 239 } 240 241 evtimer_set(&server_ev_tidy, server_tidy_event, NULL); 242 evtimer_add(&server_ev_tidy, &tv); 243 244 server_acl_init(); 245 246 server_add_accept(0); 247 proc_loop(server_proc, server_loop); 248 249 job_kill_all(); 250 status_prompt_save_history(); 251 252 exit(0); 253 } 254 255 /* Server loop callback. */ 256 static int 257 server_loop(void) 258 { 259 struct client *c; 260 u_int items; 261 262 current_time = time(NULL); 263 264 do { 265 items = cmdq_next(NULL); 266 TAILQ_FOREACH(c, &clients, entry) { 267 if (c->flags & CLIENT_IDENTIFIED) 268 items += cmdq_next(c); 269 } 270 } while (items != 0); 271 272 server_client_loop(); 273 274 if (!options_get_number(global_options, "exit-empty") && !server_exit) 275 return (0); 276 277 if (!options_get_number(global_options, "exit-unattached")) { 278 if (!RB_EMPTY(&sessions)) 279 return (0); 280 } 281 282 TAILQ_FOREACH(c, &clients, entry) { 283 if (c->session != NULL) 284 return (0); 285 } 286 287 /* 288 * No attached clients therefore want to exit - flush any waiting 289 * clients but don't actually exit until they've gone. 290 */ 291 cmd_wait_for_flush(); 292 if (!TAILQ_EMPTY(&clients)) 293 return (0); 294 295 if (job_still_running()) 296 return (0); 297 298 return (1); 299 } 300 301 /* Exit the server by killing all clients and windows. */ 302 static void 303 server_send_exit(void) 304 { 305 struct client *c, *c1; 306 struct session *s, *s1; 307 308 cmd_wait_for_flush(); 309 310 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 311 if (c->flags & CLIENT_SUSPENDED) 312 server_client_lost(c); 313 else { 314 c->flags |= CLIENT_EXIT; 315 c->exit_type = CLIENT_EXIT_SHUTDOWN; 316 } 317 c->session = NULL; 318 } 319 320 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 321 session_destroy(s, 1, __func__); 322 } 323 324 /* Update socket execute permissions based on whether sessions are attached. */ 325 void 326 server_update_socket(void) 327 { 328 struct session *s; 329 static int last = -1; 330 int n, mode; 331 struct stat sb; 332 333 n = 0; 334 RB_FOREACH(s, sessions, &sessions) { 335 if (s->attached != 0) { 336 n++; 337 break; 338 } 339 } 340 341 if (n != last) { 342 last = n; 343 344 if (stat(socket_path, &sb) != 0) 345 return; 346 mode = sb.st_mode & ACCESSPERMS; 347 if (n != 0) { 348 if (mode & S_IRUSR) 349 mode |= S_IXUSR; 350 if (mode & S_IRGRP) 351 mode |= S_IXGRP; 352 if (mode & S_IROTH) 353 mode |= S_IXOTH; 354 } else 355 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 356 chmod(socket_path, mode); 357 } 358 } 359 360 /* Callback for server socket. */ 361 static void 362 server_accept(int fd, short events, __unused void *data) 363 { 364 struct sockaddr_storage sa; 365 socklen_t slen = sizeof sa; 366 int newfd; 367 struct client *c; 368 369 server_add_accept(0); 370 if (!(events & EV_READ)) 371 return; 372 373 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 374 if (newfd == -1) { 375 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 376 return; 377 if (errno == ENFILE || errno == EMFILE) { 378 /* Delete and don't try again for 1 second. */ 379 server_add_accept(1); 380 return; 381 } 382 fatal("accept failed"); 383 } 384 385 if (server_exit) { 386 close(newfd); 387 return; 388 } 389 c = server_client_create(newfd); 390 if (!server_acl_join(c)) { 391 c->exit_message = xstrdup("access not allowed"); 392 c->flags |= CLIENT_EXIT; 393 } 394 } 395 396 /* 397 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 398 * event - used to backoff when running out of file descriptors. 399 */ 400 void 401 server_add_accept(int timeout) 402 { 403 struct timeval tv = { timeout, 0 }; 404 405 if (server_fd == -1) 406 return; 407 408 if (event_initialized(&server_ev_accept)) 409 event_del(&server_ev_accept); 410 411 if (timeout == 0) { 412 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 413 NULL); 414 event_add(&server_ev_accept, NULL); 415 } else { 416 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 417 server_accept, NULL); 418 event_add(&server_ev_accept, &tv); 419 } 420 } 421 422 /* Signal handler. */ 423 static void 424 server_signal(int sig) 425 { 426 int fd; 427 428 log_debug("%s: %s", __func__, strsignal(sig)); 429 switch (sig) { 430 case SIGINT: 431 case SIGTERM: 432 server_exit = 1; 433 server_send_exit(); 434 break; 435 case SIGCHLD: 436 server_child_signal(); 437 break; 438 case SIGUSR1: 439 event_del(&server_ev_accept); 440 fd = server_create_socket(server_client_flags, NULL); 441 if (fd != -1) { 442 close(server_fd); 443 server_fd = fd; 444 server_update_socket(); 445 } 446 server_add_accept(0); 447 break; 448 case SIGUSR2: 449 proc_toggle_log(server_proc); 450 break; 451 } 452 } 453 454 /* Handle SIGCHLD. */ 455 static void 456 server_child_signal(void) 457 { 458 int status; 459 pid_t pid; 460 461 for (;;) { 462 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 463 case -1: 464 if (errno == ECHILD) 465 return; 466 fatal("waitpid failed"); 467 case 0: 468 return; 469 } 470 if (WIFSTOPPED(status)) 471 server_child_stopped(pid, status); 472 else if (WIFEXITED(status) || WIFSIGNALED(status)) 473 server_child_exited(pid, status); 474 } 475 } 476 477 /* Handle exited children. */ 478 static void 479 server_child_exited(pid_t pid, int status) 480 { 481 struct window *w, *w1; 482 struct window_pane *wp; 483 484 RB_FOREACH_SAFE(w, windows, &windows, w1) { 485 TAILQ_FOREACH(wp, &w->panes, entry) { 486 if (wp->pid == pid) { 487 wp->status = status; 488 wp->flags |= PANE_STATUSREADY; 489 490 log_debug("%%%u exited", wp->id); 491 wp->flags |= PANE_EXITED; 492 493 if (window_pane_destroy_ready(wp)) 494 server_destroy_pane(wp, 1); 495 break; 496 } 497 } 498 } 499 job_check_died(pid, status); 500 } 501 502 /* Handle stopped children. */ 503 static void 504 server_child_stopped(pid_t pid, int status) 505 { 506 struct window *w; 507 struct window_pane *wp; 508 509 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 510 return; 511 512 RB_FOREACH(w, windows, &windows) { 513 TAILQ_FOREACH(wp, &w->panes, entry) { 514 if (wp->pid == pid) { 515 if (killpg(pid, SIGCONT) != 0) 516 kill(pid, SIGCONT); 517 } 518 } 519 } 520 job_check_died(pid, status); 521 } 522 523 /* Add to message log. */ 524 void 525 server_add_message(const char *fmt, ...) 526 { 527 struct message_entry *msg, *msg1; 528 char *s; 529 va_list ap; 530 u_int limit; 531 532 va_start(ap, fmt); 533 xvasprintf(&s, fmt, ap); 534 va_end(ap); 535 536 log_debug("message: %s", s); 537 538 msg = xcalloc(1, sizeof *msg); 539 gettimeofday(&msg->msg_time, NULL); 540 msg->msg_num = message_next++; 541 msg->msg = s; 542 TAILQ_INSERT_TAIL(&message_log, msg, entry); 543 544 limit = options_get_number(global_options, "message-limit"); 545 TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) { 546 if (msg->msg_num + limit >= message_next) 547 break; 548 free(msg->msg); 549 TAILQ_REMOVE(&message_log, msg, entry); 550 free(msg); 551 } 552 } 553