1 /* $OpenBSD: server.c,v 1.203 2022/06/30 09:55:53 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 static int 108 server_create_socket(int 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, int 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 RB_INIT(&windows); 209 RB_INIT(&all_window_panes); 210 TAILQ_INIT(&clients); 211 RB_INIT(&sessions); 212 key_bindings_init(); 213 TAILQ_INIT(&message_log); 214 gettimeofday(&start_time, NULL); 215 216 server_fd = server_create_socket(flags, &cause); 217 if (server_fd != -1) 218 server_update_socket(); 219 if (~flags & CLIENT_NOFORK) 220 c = server_client_create(fd); 221 else 222 options_set_number(global_options, "exit-empty", 0); 223 224 if (lockfd >= 0) { 225 unlink(lockfile); 226 free(lockfile); 227 close(lockfd); 228 } 229 230 if (cause != NULL) { 231 if (c != NULL) { 232 c->exit_message = cause; 233 c->flags |= CLIENT_EXIT; 234 } else { 235 fprintf(stderr, "%s\n", cause); 236 exit(1); 237 } 238 } 239 240 evtimer_set(&server_ev_tidy, server_tidy_event, NULL); 241 evtimer_add(&server_ev_tidy, &tv); 242 243 server_acl_init(); 244 245 server_add_accept(0); 246 proc_loop(server_proc, server_loop); 247 248 job_kill_all(); 249 status_prompt_save_history(); 250 251 exit(0); 252 } 253 254 /* Server loop callback. */ 255 static int 256 server_loop(void) 257 { 258 struct client *c; 259 u_int items; 260 261 current_time = time (NULL); 262 263 do { 264 items = cmdq_next(NULL); 265 TAILQ_FOREACH(c, &clients, entry) { 266 if (c->flags & CLIENT_IDENTIFIED) 267 items += cmdq_next(c); 268 } 269 } while (items != 0); 270 271 server_client_loop(); 272 273 if (!options_get_number(global_options, "exit-empty") && !server_exit) 274 return (0); 275 276 if (!options_get_number(global_options, "exit-unattached")) { 277 if (!RB_EMPTY(&sessions)) 278 return (0); 279 } 280 281 TAILQ_FOREACH(c, &clients, entry) { 282 if (c->session != NULL) 283 return (0); 284 } 285 286 /* 287 * No attached clients therefore want to exit - flush any waiting 288 * clients but don't actually exit until they've gone. 289 */ 290 cmd_wait_for_flush(); 291 if (!TAILQ_EMPTY(&clients)) 292 return (0); 293 294 if (job_still_running()) 295 return (0); 296 297 return (1); 298 } 299 300 /* Exit the server by killing all clients and windows. */ 301 static void 302 server_send_exit(void) 303 { 304 struct client *c, *c1; 305 struct session *s, *s1; 306 307 cmd_wait_for_flush(); 308 309 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 310 if (c->flags & CLIENT_SUSPENDED) 311 server_client_lost(c); 312 else { 313 c->flags |= CLIENT_EXIT; 314 c->exit_type = CLIENT_EXIT_SHUTDOWN; 315 } 316 c->session = NULL; 317 } 318 319 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 320 session_destroy(s, 1, __func__); 321 } 322 323 /* Update socket execute permissions based on whether sessions are attached. */ 324 void 325 server_update_socket(void) 326 { 327 struct session *s; 328 static int last = -1; 329 int n, mode; 330 struct stat sb; 331 332 n = 0; 333 RB_FOREACH(s, sessions, &sessions) { 334 if (s->attached != 0) { 335 n++; 336 break; 337 } 338 } 339 340 if (n != last) { 341 last = n; 342 343 if (stat(socket_path, &sb) != 0) 344 return; 345 mode = sb.st_mode & ACCESSPERMS; 346 if (n != 0) { 347 if (mode & S_IRUSR) 348 mode |= S_IXUSR; 349 if (mode & S_IRGRP) 350 mode |= S_IXGRP; 351 if (mode & S_IROTH) 352 mode |= S_IXOTH; 353 } else 354 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 355 chmod(socket_path, mode); 356 } 357 } 358 359 /* Callback for server socket. */ 360 static void 361 server_accept(int fd, short events, __unused void *data) 362 { 363 struct sockaddr_storage sa; 364 socklen_t slen = sizeof sa; 365 int newfd; 366 struct client *c; 367 368 server_add_accept(0); 369 if (!(events & EV_READ)) 370 return; 371 372 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 373 if (newfd == -1) { 374 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 375 return; 376 if (errno == ENFILE || errno == EMFILE) { 377 /* Delete and don't try again for 1 second. */ 378 server_add_accept(1); 379 return; 380 } 381 fatal("accept failed"); 382 } 383 384 if (server_exit) { 385 close(newfd); 386 return; 387 } 388 c = server_client_create(newfd); 389 if (!server_acl_join(c)) { 390 c->exit_message = xstrdup("access not allowed"); 391 c->flags |= CLIENT_EXIT; 392 } 393 } 394 395 /* 396 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 397 * event - used to backoff when running out of file descriptors. 398 */ 399 void 400 server_add_accept(int timeout) 401 { 402 struct timeval tv = { timeout, 0 }; 403 404 if (server_fd == -1) 405 return; 406 407 if (event_initialized(&server_ev_accept)) 408 event_del(&server_ev_accept); 409 410 if (timeout == 0) { 411 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 412 NULL); 413 event_add(&server_ev_accept, NULL); 414 } else { 415 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 416 server_accept, NULL); 417 event_add(&server_ev_accept, &tv); 418 } 419 } 420 421 /* Signal handler. */ 422 static void 423 server_signal(int sig) 424 { 425 int fd; 426 427 log_debug("%s: %s", __func__, strsignal(sig)); 428 switch (sig) { 429 case SIGINT: 430 case SIGTERM: 431 server_exit = 1; 432 server_send_exit(); 433 break; 434 case SIGCHLD: 435 server_child_signal(); 436 break; 437 case SIGUSR1: 438 event_del(&server_ev_accept); 439 fd = server_create_socket(server_client_flags, NULL); 440 if (fd != -1) { 441 close(server_fd); 442 server_fd = fd; 443 server_update_socket(); 444 } 445 server_add_accept(0); 446 break; 447 case SIGUSR2: 448 proc_toggle_log(server_proc); 449 break; 450 } 451 } 452 453 /* Handle SIGCHLD. */ 454 static void 455 server_child_signal(void) 456 { 457 int status; 458 pid_t pid; 459 460 for (;;) { 461 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 462 case -1: 463 if (errno == ECHILD) 464 return; 465 fatal("waitpid failed"); 466 case 0: 467 return; 468 } 469 if (WIFSTOPPED(status)) 470 server_child_stopped(pid, status); 471 else if (WIFEXITED(status) || WIFSIGNALED(status)) 472 server_child_exited(pid, status); 473 } 474 } 475 476 /* Handle exited children. */ 477 static void 478 server_child_exited(pid_t pid, int status) 479 { 480 struct window *w, *w1; 481 struct window_pane *wp; 482 483 RB_FOREACH_SAFE(w, windows, &windows, w1) { 484 TAILQ_FOREACH(wp, &w->panes, entry) { 485 if (wp->pid == pid) { 486 wp->status = status; 487 wp->flags |= PANE_STATUSREADY; 488 489 log_debug("%%%u exited", wp->id); 490 wp->flags |= PANE_EXITED; 491 492 if (window_pane_destroy_ready(wp)) 493 server_destroy_pane(wp, 1); 494 break; 495 } 496 } 497 } 498 job_check_died(pid, status); 499 } 500 501 /* Handle stopped children. */ 502 static void 503 server_child_stopped(pid_t pid, int status) 504 { 505 struct window *w; 506 struct window_pane *wp; 507 508 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 509 return; 510 511 RB_FOREACH(w, windows, &windows) { 512 TAILQ_FOREACH(wp, &w->panes, entry) { 513 if (wp->pid == pid) { 514 if (killpg(pid, SIGCONT) != 0) 515 kill(pid, SIGCONT); 516 } 517 } 518 } 519 job_check_died(pid, status); 520 } 521 522 /* Add to message log. */ 523 void 524 server_add_message(const char *fmt, ...) 525 { 526 struct message_entry *msg, *msg1; 527 char *s; 528 va_list ap; 529 u_int limit; 530 531 va_start(ap, fmt); 532 xvasprintf(&s, fmt, ap); 533 va_end(ap); 534 535 log_debug("message: %s", s); 536 537 msg = xcalloc(1, sizeof *msg); 538 gettimeofday(&msg->msg_time, NULL); 539 msg->msg_num = message_next++; 540 msg->msg = s; 541 TAILQ_INSERT_TAIL(&message_log, msg, entry); 542 543 limit = options_get_number(global_options, "message-limit"); 544 TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) { 545 if (msg->msg_num + limit >= message_next) 546 break; 547 free(msg->msg); 548 TAILQ_REMOVE(&message_log, msg, entry); 549 free(msg); 550 } 551 } 552