1 /* $OpenBSD: server.c,v 1.198 2021/06/10 07:45:43 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 static int server_loop(void); 59 static void server_send_exit(void); 60 static void server_accept(int, short, void *); 61 static void server_signal(int); 62 static void server_child_signal(void); 63 static void server_child_exited(pid_t, int); 64 static 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 cmd_find_clear_state(&marked_pane, 0); 71 marked_pane.s = s; 72 marked_pane.wl = wl; 73 marked_pane.w = wl->window; 74 marked_pane.wp = wp; 75 } 76 77 /* Clear marked pane. */ 78 void 79 server_clear_marked(void) 80 { 81 cmd_find_clear_state(&marked_pane, 0); 82 } 83 84 /* Is this the marked pane? */ 85 int 86 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 87 { 88 if (s == NULL || wl == NULL || wp == NULL) 89 return (0); 90 if (marked_pane.s != s || marked_pane.wl != wl) 91 return (0); 92 if (marked_pane.wp != wp) 93 return (0); 94 return (server_check_marked()); 95 } 96 97 /* Check if the marked pane is still valid. */ 98 int 99 server_check_marked(void) 100 { 101 return (cmd_find_valid_state(&marked_pane)); 102 } 103 104 /* Create server socket. */ 105 static int 106 server_create_socket(int flags, char **cause) 107 { 108 struct sockaddr_un sa; 109 size_t size; 110 mode_t mask; 111 int fd, saved_errno; 112 113 memset(&sa, 0, sizeof sa); 114 sa.sun_family = AF_UNIX; 115 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 116 if (size >= sizeof sa.sun_path) { 117 errno = ENAMETOOLONG; 118 goto fail; 119 } 120 unlink(sa.sun_path); 121 122 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 123 goto fail; 124 125 if (flags & CLIENT_DEFAULTSOCKET) 126 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 127 else 128 mask = umask(S_IXUSR|S_IRWXG|S_IRWXO); 129 if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 130 saved_errno = errno; 131 close(fd); 132 errno = saved_errno; 133 goto fail; 134 } 135 umask(mask); 136 137 if (listen(fd, 128) == -1) { 138 saved_errno = errno; 139 close(fd); 140 errno = saved_errno; 141 goto fail; 142 } 143 setblocking(fd, 0); 144 145 return (fd); 146 147 fail: 148 if (cause != NULL) { 149 xasprintf(cause, "error creating %s (%s)", socket_path, 150 strerror(errno)); 151 } 152 return (-1); 153 } 154 155 /* Tidy up every hour. */ 156 static void 157 server_tidy_event(__unused int fd, __unused short events, __unused void *data) 158 { 159 struct timeval tv = { .tv_sec = 3600 }; 160 uint64_t t = get_timer(); 161 162 format_tidy_jobs(); 163 164 log_debug("%s: took %llu milliseconds", __func__, 165 (unsigned long long)(get_timer() - t)); 166 evtimer_add(&server_ev_tidy, &tv); 167 } 168 169 /* Fork new server. */ 170 int 171 server_start(struct tmuxproc *client, int flags, struct event_base *base, 172 int lockfd, char *lockfile) 173 { 174 int fd; 175 sigset_t set, oldset; 176 struct client *c = NULL; 177 char *cause = NULL; 178 struct timeval tv = { .tv_sec = 3600 }; 179 180 sigfillset(&set); 181 sigprocmask(SIG_BLOCK, &set, &oldset); 182 183 if (~flags & CLIENT_NOFORK) { 184 if (proc_fork_and_daemon(&fd) != 0) { 185 sigprocmask(SIG_SETMASK, &oldset, NULL); 186 return (fd); 187 } 188 } 189 proc_clear_signals(client, 0); 190 server_client_flags = flags; 191 192 if (event_reinit(base) != 0) 193 fatalx("event_reinit failed"); 194 server_proc = proc_start("server"); 195 196 proc_set_signals(server_proc, server_signal); 197 sigprocmask(SIG_SETMASK, &oldset, NULL); 198 199 if (log_get_level() > 1) 200 tty_create_log(); 201 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 202 "tty ps", NULL) != 0) 203 fatal("pledge failed"); 204 205 input_key_build(); 206 RB_INIT(&windows); 207 RB_INIT(&all_window_panes); 208 TAILQ_INIT(&clients); 209 RB_INIT(&sessions); 210 key_bindings_init(); 211 TAILQ_INIT(&message_log); 212 213 gettimeofday(&start_time, NULL); 214 215 server_fd = server_create_socket(flags, &cause); 216 if (server_fd != -1) 217 server_update_socket(); 218 if (~flags & CLIENT_NOFORK) 219 c = server_client_create(fd); 220 else 221 options_set_number(global_options, "exit-empty", 0); 222 223 if (lockfd >= 0) { 224 unlink(lockfile); 225 free(lockfile); 226 close(lockfd); 227 } 228 229 if (cause != NULL) { 230 if (c != NULL) { 231 cmdq_append(c, cmdq_get_error(cause)); 232 c->flags |= CLIENT_EXIT; 233 } 234 free(cause); 235 } 236 237 evtimer_set(&server_ev_tidy, server_tidy_event, NULL); 238 evtimer_add(&server_ev_tidy, &tv); 239 240 server_add_accept(0); 241 proc_loop(server_proc, server_loop); 242 243 job_kill_all(); 244 status_prompt_save_history(); 245 246 exit(0); 247 } 248 249 /* Server loop callback. */ 250 static int 251 server_loop(void) 252 { 253 struct client *c; 254 u_int items; 255 256 do { 257 items = cmdq_next(NULL); 258 TAILQ_FOREACH(c, &clients, entry) { 259 if (c->flags & CLIENT_IDENTIFIED) 260 items += cmdq_next(c); 261 } 262 } while (items != 0); 263 264 server_client_loop(); 265 266 if (!options_get_number(global_options, "exit-empty") && !server_exit) 267 return (0); 268 269 if (!options_get_number(global_options, "exit-unattached")) { 270 if (!RB_EMPTY(&sessions)) 271 return (0); 272 } 273 274 TAILQ_FOREACH(c, &clients, entry) { 275 if (c->session != NULL) 276 return (0); 277 } 278 279 /* 280 * No attached clients therefore want to exit - flush any waiting 281 * clients but don't actually exit until they've gone. 282 */ 283 cmd_wait_for_flush(); 284 if (!TAILQ_EMPTY(&clients)) 285 return (0); 286 287 if (job_still_running()) 288 return (0); 289 290 return (1); 291 } 292 293 /* Exit the server by killing all clients and windows. */ 294 static void 295 server_send_exit(void) 296 { 297 struct client *c, *c1; 298 struct session *s, *s1; 299 300 cmd_wait_for_flush(); 301 302 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 303 if (c->flags & CLIENT_SUSPENDED) 304 server_client_lost(c); 305 else { 306 c->flags |= CLIENT_EXIT; 307 c->exit_type = CLIENT_EXIT_SHUTDOWN; 308 } 309 c->session = NULL; 310 } 311 312 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 313 session_destroy(s, 1, __func__); 314 } 315 316 /* Update socket execute permissions based on whether sessions are attached. */ 317 void 318 server_update_socket(void) 319 { 320 struct session *s; 321 static int last = -1; 322 int n, mode; 323 struct stat sb; 324 325 n = 0; 326 RB_FOREACH(s, sessions, &sessions) { 327 if (s->attached != 0) { 328 n++; 329 break; 330 } 331 } 332 333 if (n != last) { 334 last = n; 335 336 if (stat(socket_path, &sb) != 0) 337 return; 338 mode = sb.st_mode & ACCESSPERMS; 339 if (n != 0) { 340 if (mode & S_IRUSR) 341 mode |= S_IXUSR; 342 if (mode & S_IRGRP) 343 mode |= S_IXGRP; 344 if (mode & S_IROTH) 345 mode |= S_IXOTH; 346 } else 347 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 348 chmod(socket_path, mode); 349 } 350 } 351 352 /* Callback for server socket. */ 353 static void 354 server_accept(int fd, short events, __unused void *data) 355 { 356 struct sockaddr_storage sa; 357 socklen_t slen = sizeof sa; 358 int newfd; 359 360 server_add_accept(0); 361 if (!(events & EV_READ)) 362 return; 363 364 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 365 if (newfd == -1) { 366 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 367 return; 368 if (errno == ENFILE || errno == EMFILE) { 369 /* Delete and don't try again for 1 second. */ 370 server_add_accept(1); 371 return; 372 } 373 fatal("accept failed"); 374 } 375 if (server_exit) { 376 close(newfd); 377 return; 378 } 379 server_client_create(newfd); 380 } 381 382 /* 383 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 384 * event - used to backoff when running out of file descriptors. 385 */ 386 void 387 server_add_accept(int timeout) 388 { 389 struct timeval tv = { timeout, 0 }; 390 391 if (server_fd == -1) 392 return; 393 394 if (event_initialized(&server_ev_accept)) 395 event_del(&server_ev_accept); 396 397 if (timeout == 0) { 398 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 399 NULL); 400 event_add(&server_ev_accept, NULL); 401 } else { 402 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 403 server_accept, NULL); 404 event_add(&server_ev_accept, &tv); 405 } 406 } 407 408 /* Signal handler. */ 409 static void 410 server_signal(int sig) 411 { 412 int fd; 413 414 log_debug("%s: %s", __func__, strsignal(sig)); 415 switch (sig) { 416 case SIGINT: 417 case SIGTERM: 418 server_exit = 1; 419 server_send_exit(); 420 break; 421 case SIGCHLD: 422 server_child_signal(); 423 break; 424 case SIGUSR1: 425 event_del(&server_ev_accept); 426 fd = server_create_socket(server_client_flags, NULL); 427 if (fd != -1) { 428 close(server_fd); 429 server_fd = fd; 430 server_update_socket(); 431 } 432 server_add_accept(0); 433 break; 434 case SIGUSR2: 435 proc_toggle_log(server_proc); 436 break; 437 } 438 } 439 440 /* Handle SIGCHLD. */ 441 static void 442 server_child_signal(void) 443 { 444 int status; 445 pid_t pid; 446 447 for (;;) { 448 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 449 case -1: 450 if (errno == ECHILD) 451 return; 452 fatal("waitpid failed"); 453 case 0: 454 return; 455 } 456 if (WIFSTOPPED(status)) 457 server_child_stopped(pid, status); 458 else if (WIFEXITED(status) || WIFSIGNALED(status)) 459 server_child_exited(pid, status); 460 } 461 } 462 463 /* Handle exited children. */ 464 static void 465 server_child_exited(pid_t pid, int status) 466 { 467 struct window *w, *w1; 468 struct window_pane *wp; 469 470 RB_FOREACH_SAFE(w, windows, &windows, w1) { 471 TAILQ_FOREACH(wp, &w->panes, entry) { 472 if (wp->pid == pid) { 473 wp->status = status; 474 wp->flags |= PANE_STATUSREADY; 475 476 log_debug("%%%u exited", wp->id); 477 wp->flags |= PANE_EXITED; 478 479 if (window_pane_destroy_ready(wp)) 480 server_destroy_pane(wp, 1); 481 break; 482 } 483 } 484 } 485 job_check_died(pid, status); 486 } 487 488 /* Handle stopped children. */ 489 static void 490 server_child_stopped(pid_t pid, int status) 491 { 492 struct window *w; 493 struct window_pane *wp; 494 495 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 496 return; 497 498 RB_FOREACH(w, windows, &windows) { 499 TAILQ_FOREACH(wp, &w->panes, entry) { 500 if (wp->pid == pid) { 501 if (killpg(pid, SIGCONT) != 0) 502 kill(pid, SIGCONT); 503 } 504 } 505 } 506 job_check_died(pid, status); 507 } 508 509 /* Add to message log. */ 510 void 511 server_add_message(const char *fmt, ...) 512 { 513 struct message_entry *msg, *msg1; 514 char *s; 515 va_list ap; 516 u_int limit; 517 518 va_start(ap, fmt); 519 xvasprintf(&s, fmt, ap); 520 va_end(ap); 521 522 log_debug("message: %s", s); 523 524 msg = xcalloc(1, sizeof *msg); 525 gettimeofday(&msg->msg_time, NULL); 526 msg->msg_num = message_next++; 527 msg->msg = s; 528 TAILQ_INSERT_TAIL(&message_log, msg, entry); 529 530 limit = options_get_number(global_options, "message-limit"); 531 TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) { 532 if (msg->msg_num + limit >= message_next) 533 break; 534 free(msg->msg); 535 TAILQ_REMOVE(&message_log, msg, entry); 536 free(msg); 537 } 538 } 539