1 /* $OpenBSD: server.c,v 1.197 2021/03/11 07:08:18 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__, get_timer() - t); 165 evtimer_add(&server_ev_tidy, &tv); 166 } 167 168 /* Fork new server. */ 169 int 170 server_start(struct tmuxproc *client, int flags, struct event_base *base, 171 int lockfd, char *lockfile) 172 { 173 int fd; 174 sigset_t set, oldset; 175 struct client *c = NULL; 176 char *cause = NULL; 177 struct timeval tv = { .tv_sec = 3600 }; 178 179 sigfillset(&set); 180 sigprocmask(SIG_BLOCK, &set, &oldset); 181 182 if (~flags & CLIENT_NOFORK) { 183 if (proc_fork_and_daemon(&fd) != 0) { 184 sigprocmask(SIG_SETMASK, &oldset, NULL); 185 return (fd); 186 } 187 } 188 proc_clear_signals(client, 0); 189 server_client_flags = flags; 190 191 if (event_reinit(base) != 0) 192 fatalx("event_reinit failed"); 193 server_proc = proc_start("server"); 194 195 proc_set_signals(server_proc, server_signal); 196 sigprocmask(SIG_SETMASK, &oldset, NULL); 197 198 if (log_get_level() > 1) 199 tty_create_log(); 200 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 201 "tty ps", NULL) != 0) 202 fatal("pledge failed"); 203 204 input_key_build(); 205 RB_INIT(&windows); 206 RB_INIT(&all_window_panes); 207 TAILQ_INIT(&clients); 208 RB_INIT(&sessions); 209 key_bindings_init(); 210 TAILQ_INIT(&message_log); 211 212 gettimeofday(&start_time, NULL); 213 214 server_fd = server_create_socket(flags, &cause); 215 if (server_fd != -1) 216 server_update_socket(); 217 if (~flags & CLIENT_NOFORK) 218 c = server_client_create(fd); 219 else 220 options_set_number(global_options, "exit-empty", 0); 221 222 if (lockfd >= 0) { 223 unlink(lockfile); 224 free(lockfile); 225 close(lockfd); 226 } 227 228 if (cause != NULL) { 229 if (c != NULL) { 230 cmdq_append(c, cmdq_get_error(cause)); 231 c->flags |= CLIENT_EXIT; 232 } 233 free(cause); 234 } 235 236 evtimer_set(&server_ev_tidy, server_tidy_event, NULL); 237 evtimer_add(&server_ev_tidy, &tv); 238 239 server_add_accept(0); 240 proc_loop(server_proc, server_loop); 241 242 job_kill_all(); 243 status_prompt_save_history(); 244 245 exit(0); 246 } 247 248 /* Server loop callback. */ 249 static int 250 server_loop(void) 251 { 252 struct client *c; 253 u_int items; 254 255 do { 256 items = cmdq_next(NULL); 257 TAILQ_FOREACH(c, &clients, entry) { 258 if (c->flags & CLIENT_IDENTIFIED) 259 items += cmdq_next(c); 260 } 261 } while (items != 0); 262 263 server_client_loop(); 264 265 if (!options_get_number(global_options, "exit-empty") && !server_exit) 266 return (0); 267 268 if (!options_get_number(global_options, "exit-unattached")) { 269 if (!RB_EMPTY(&sessions)) 270 return (0); 271 } 272 273 TAILQ_FOREACH(c, &clients, entry) { 274 if (c->session != NULL) 275 return (0); 276 } 277 278 /* 279 * No attached clients therefore want to exit - flush any waiting 280 * clients but don't actually exit until they've gone. 281 */ 282 cmd_wait_for_flush(); 283 if (!TAILQ_EMPTY(&clients)) 284 return (0); 285 286 if (job_still_running()) 287 return (0); 288 289 return (1); 290 } 291 292 /* Exit the server by killing all clients and windows. */ 293 static void 294 server_send_exit(void) 295 { 296 struct client *c, *c1; 297 struct session *s, *s1; 298 299 cmd_wait_for_flush(); 300 301 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 302 if (c->flags & CLIENT_SUSPENDED) 303 server_client_lost(c); 304 else { 305 c->flags |= CLIENT_EXIT; 306 c->exit_type = CLIENT_EXIT_SHUTDOWN; 307 } 308 c->session = NULL; 309 } 310 311 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 312 session_destroy(s, 1, __func__); 313 } 314 315 /* Update socket execute permissions based on whether sessions are attached. */ 316 void 317 server_update_socket(void) 318 { 319 struct session *s; 320 static int last = -1; 321 int n, mode; 322 struct stat sb; 323 324 n = 0; 325 RB_FOREACH(s, sessions, &sessions) { 326 if (s->attached != 0) { 327 n++; 328 break; 329 } 330 } 331 332 if (n != last) { 333 last = n; 334 335 if (stat(socket_path, &sb) != 0) 336 return; 337 mode = sb.st_mode & ACCESSPERMS; 338 if (n != 0) { 339 if (mode & S_IRUSR) 340 mode |= S_IXUSR; 341 if (mode & S_IRGRP) 342 mode |= S_IXGRP; 343 if (mode & S_IROTH) 344 mode |= S_IXOTH; 345 } else 346 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 347 chmod(socket_path, mode); 348 } 349 } 350 351 /* Callback for server socket. */ 352 static void 353 server_accept(int fd, short events, __unused void *data) 354 { 355 struct sockaddr_storage sa; 356 socklen_t slen = sizeof sa; 357 int newfd; 358 359 server_add_accept(0); 360 if (!(events & EV_READ)) 361 return; 362 363 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 364 if (newfd == -1) { 365 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 366 return; 367 if (errno == ENFILE || errno == EMFILE) { 368 /* Delete and don't try again for 1 second. */ 369 server_add_accept(1); 370 return; 371 } 372 fatal("accept failed"); 373 } 374 if (server_exit) { 375 close(newfd); 376 return; 377 } 378 server_client_create(newfd); 379 } 380 381 /* 382 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 383 * event - used to backoff when running out of file descriptors. 384 */ 385 void 386 server_add_accept(int timeout) 387 { 388 struct timeval tv = { timeout, 0 }; 389 390 if (server_fd == -1) 391 return; 392 393 if (event_initialized(&server_ev_accept)) 394 event_del(&server_ev_accept); 395 396 if (timeout == 0) { 397 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 398 NULL); 399 event_add(&server_ev_accept, NULL); 400 } else { 401 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 402 server_accept, NULL); 403 event_add(&server_ev_accept, &tv); 404 } 405 } 406 407 /* Signal handler. */ 408 static void 409 server_signal(int sig) 410 { 411 int fd; 412 413 log_debug("%s: %s", __func__, strsignal(sig)); 414 switch (sig) { 415 case SIGINT: 416 case SIGTERM: 417 server_exit = 1; 418 server_send_exit(); 419 break; 420 case SIGCHLD: 421 server_child_signal(); 422 break; 423 case SIGUSR1: 424 event_del(&server_ev_accept); 425 fd = server_create_socket(server_client_flags, NULL); 426 if (fd != -1) { 427 close(server_fd); 428 server_fd = fd; 429 server_update_socket(); 430 } 431 server_add_accept(0); 432 break; 433 case SIGUSR2: 434 proc_toggle_log(server_proc); 435 break; 436 } 437 } 438 439 /* Handle SIGCHLD. */ 440 static void 441 server_child_signal(void) 442 { 443 int status; 444 pid_t pid; 445 446 for (;;) { 447 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 448 case -1: 449 if (errno == ECHILD) 450 return; 451 fatal("waitpid failed"); 452 case 0: 453 return; 454 } 455 if (WIFSTOPPED(status)) 456 server_child_stopped(pid, status); 457 else if (WIFEXITED(status) || WIFSIGNALED(status)) 458 server_child_exited(pid, status); 459 } 460 } 461 462 /* Handle exited children. */ 463 static void 464 server_child_exited(pid_t pid, int status) 465 { 466 struct window *w, *w1; 467 struct window_pane *wp; 468 469 RB_FOREACH_SAFE(w, windows, &windows, w1) { 470 TAILQ_FOREACH(wp, &w->panes, entry) { 471 if (wp->pid == pid) { 472 wp->status = status; 473 wp->flags |= PANE_STATUSREADY; 474 475 log_debug("%%%u exited", wp->id); 476 wp->flags |= PANE_EXITED; 477 478 if (window_pane_destroy_ready(wp)) 479 server_destroy_pane(wp, 1); 480 break; 481 } 482 } 483 } 484 job_check_died(pid, status); 485 } 486 487 /* Handle stopped children. */ 488 static void 489 server_child_stopped(pid_t pid, int status) 490 { 491 struct window *w; 492 struct window_pane *wp; 493 494 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 495 return; 496 497 RB_FOREACH(w, windows, &windows) { 498 TAILQ_FOREACH(wp, &w->panes, entry) { 499 if (wp->pid == pid) { 500 if (killpg(pid, SIGCONT) != 0) 501 kill(pid, SIGCONT); 502 } 503 } 504 } 505 job_check_died(pid, status); 506 } 507 508 /* Add to message log. */ 509 void 510 server_add_message(const char *fmt, ...) 511 { 512 struct message_entry *msg, *msg1; 513 char *s; 514 va_list ap; 515 u_int limit; 516 517 va_start(ap, fmt); 518 xvasprintf(&s, fmt, ap); 519 va_end(ap); 520 521 log_debug("message: %s", s); 522 523 msg = xcalloc(1, sizeof *msg); 524 gettimeofday(&msg->msg_time, NULL); 525 msg->msg_num = message_next++; 526 msg->msg = s; 527 TAILQ_INSERT_TAIL(&message_log, msg, entry); 528 529 limit = options_get_number(global_options, "message-limit"); 530 TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) { 531 if (msg->msg_num + limit >= message_next) 532 break; 533 free(msg->msg); 534 TAILQ_REMOVE(&message_log, msg, entry); 535 free(msg); 536 } 537 } 538