1 /* $OpenBSD: server.c,v 1.194 2020/06/18 08:34:22 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 52 struct cmd_find_state marked_pane; 53 54 static u_int message_next; 55 struct message_list message_log; 56 57 static int server_loop(void); 58 static void server_send_exit(void); 59 static void server_accept(int, short, void *); 60 static void server_signal(int); 61 static void server_child_signal(void); 62 static void server_child_exited(pid_t, int); 63 static void server_child_stopped(pid_t, int); 64 65 /* Set marked pane. */ 66 void 67 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 68 { 69 cmd_find_clear_state(&marked_pane, 0); 70 marked_pane.s = s; 71 marked_pane.wl = wl; 72 marked_pane.w = wl->window; 73 marked_pane.wp = wp; 74 } 75 76 /* Clear marked pane. */ 77 void 78 server_clear_marked(void) 79 { 80 cmd_find_clear_state(&marked_pane, 0); 81 } 82 83 /* Is this the marked pane? */ 84 int 85 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 86 { 87 if (s == NULL || wl == NULL || wp == NULL) 88 return (0); 89 if (marked_pane.s != s || marked_pane.wl != wl) 90 return (0); 91 if (marked_pane.wp != wp) 92 return (0); 93 return (server_check_marked()); 94 } 95 96 /* Check if the marked pane is still valid. */ 97 int 98 server_check_marked(void) 99 { 100 return (cmd_find_valid_state(&marked_pane)); 101 } 102 103 /* Create server socket. */ 104 static int 105 server_create_socket(int flags, char **cause) 106 { 107 struct sockaddr_un sa; 108 size_t size; 109 mode_t mask; 110 int fd, saved_errno; 111 112 memset(&sa, 0, sizeof sa); 113 sa.sun_family = AF_UNIX; 114 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 115 if (size >= sizeof sa.sun_path) { 116 errno = ENAMETOOLONG; 117 goto fail; 118 } 119 unlink(sa.sun_path); 120 121 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 122 goto fail; 123 124 if (flags & CLIENT_DEFAULTSOCKET) 125 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 126 else 127 mask = umask(S_IXUSR|S_IRWXG|S_IRWXO); 128 if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 129 saved_errno = errno; 130 close(fd); 131 errno = saved_errno; 132 goto fail; 133 } 134 umask(mask); 135 136 if (listen(fd, 128) == -1) { 137 saved_errno = errno; 138 close(fd); 139 errno = saved_errno; 140 goto fail; 141 } 142 setblocking(fd, 0); 143 144 return (fd); 145 146 fail: 147 if (cause != NULL) { 148 xasprintf(cause, "error creating %s (%s)", socket_path, 149 strerror(errno)); 150 } 151 return (-1); 152 } 153 154 /* Fork new server. */ 155 int 156 server_start(struct tmuxproc *client, int flags, struct event_base *base, 157 int lockfd, char *lockfile) 158 { 159 int pair[2]; 160 sigset_t set, oldset; 161 struct client *c; 162 char *cause = NULL; 163 164 sigfillset(&set); 165 sigprocmask(SIG_BLOCK, &set, &oldset); 166 167 if (~flags & CLIENT_NOFORK) { 168 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 169 fatal("socketpair failed"); 170 171 switch (fork()) { 172 case -1: 173 fatal("fork failed"); 174 case 0: 175 break; 176 default: 177 sigprocmask(SIG_SETMASK, &oldset, NULL); 178 close(pair[1]); 179 return (pair[0]); 180 } 181 close(pair[0]); 182 if (daemon(1, 0) != 0) 183 fatal("daemon failed"); 184 } 185 186 server_client_flags = flags; 187 proc_clear_signals(client, 0); 188 189 if (event_reinit(base) != 0) 190 fatalx("event_reinit failed"); 191 server_proc = proc_start("server"); 192 193 proc_set_signals(server_proc, server_signal); 194 sigprocmask(SIG_SETMASK, &oldset, NULL); 195 196 if (log_get_level() > 1) 197 tty_create_log(); 198 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 199 "tty ps", NULL) != 0) 200 fatal("pledge failed"); 201 202 input_key_build(); 203 RB_INIT(&windows); 204 RB_INIT(&all_window_panes); 205 TAILQ_INIT(&clients); 206 RB_INIT(&sessions); 207 key_bindings_init(); 208 TAILQ_INIT(&message_log); 209 210 gettimeofday(&start_time, NULL); 211 212 server_fd = server_create_socket(flags, &cause); 213 if (server_fd != -1) 214 server_update_socket(); 215 if (~flags & CLIENT_NOFORK) 216 c = server_client_create(pair[1]); 217 else 218 options_set_number(global_options, "exit-empty", 0); 219 220 if (lockfd >= 0) { 221 unlink(lockfile); 222 free(lockfile); 223 close(lockfd); 224 } 225 226 if (cause != NULL) { 227 cmdq_append(c, cmdq_get_error(cause)); 228 free(cause); 229 c->flags |= CLIENT_EXIT; 230 } 231 232 server_add_accept(0); 233 proc_loop(server_proc, server_loop); 234 235 job_kill_all(); 236 status_prompt_save_history(); 237 238 exit(0); 239 } 240 241 /* Server loop callback. */ 242 static int 243 server_loop(void) 244 { 245 struct client *c; 246 u_int items; 247 248 do { 249 items = cmdq_next(NULL); 250 TAILQ_FOREACH(c, &clients, entry) { 251 if (c->flags & CLIENT_IDENTIFIED) 252 items += cmdq_next(c); 253 } 254 } while (items != 0); 255 256 server_client_loop(); 257 258 if (!options_get_number(global_options, "exit-empty") && !server_exit) 259 return (0); 260 261 if (!options_get_number(global_options, "exit-unattached")) { 262 if (!RB_EMPTY(&sessions)) 263 return (0); 264 } 265 266 TAILQ_FOREACH(c, &clients, entry) { 267 if (c->session != NULL) 268 return (0); 269 } 270 271 /* 272 * No attached clients therefore want to exit - flush any waiting 273 * clients but don't actually exit until they've gone. 274 */ 275 cmd_wait_for_flush(); 276 if (!TAILQ_EMPTY(&clients)) 277 return (0); 278 279 if (job_still_running()) 280 return (0); 281 282 return (1); 283 } 284 285 /* Exit the server by killing all clients and windows. */ 286 static void 287 server_send_exit(void) 288 { 289 struct client *c, *c1; 290 struct session *s, *s1; 291 292 cmd_wait_for_flush(); 293 294 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 295 if (c->flags & CLIENT_SUSPENDED) 296 server_client_lost(c); 297 else { 298 c->flags |= CLIENT_EXIT; 299 c->exit_type = CLIENT_EXIT_SHUTDOWN; 300 } 301 c->session = NULL; 302 } 303 304 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 305 session_destroy(s, 1, __func__); 306 } 307 308 /* Update socket execute permissions based on whether sessions are attached. */ 309 void 310 server_update_socket(void) 311 { 312 struct session *s; 313 static int last = -1; 314 int n, mode; 315 struct stat sb; 316 317 n = 0; 318 RB_FOREACH(s, sessions, &sessions) { 319 if (s->attached != 0) { 320 n++; 321 break; 322 } 323 } 324 325 if (n != last) { 326 last = n; 327 328 if (stat(socket_path, &sb) != 0) 329 return; 330 mode = sb.st_mode & ACCESSPERMS; 331 if (n != 0) { 332 if (mode & S_IRUSR) 333 mode |= S_IXUSR; 334 if (mode & S_IRGRP) 335 mode |= S_IXGRP; 336 if (mode & S_IROTH) 337 mode |= S_IXOTH; 338 } else 339 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 340 chmod(socket_path, mode); 341 } 342 } 343 344 /* Callback for server socket. */ 345 static void 346 server_accept(int fd, short events, __unused void *data) 347 { 348 struct sockaddr_storage sa; 349 socklen_t slen = sizeof sa; 350 int newfd; 351 352 server_add_accept(0); 353 if (!(events & EV_READ)) 354 return; 355 356 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 357 if (newfd == -1) { 358 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 359 return; 360 if (errno == ENFILE || errno == EMFILE) { 361 /* Delete and don't try again for 1 second. */ 362 server_add_accept(1); 363 return; 364 } 365 fatal("accept failed"); 366 } 367 if (server_exit) { 368 close(newfd); 369 return; 370 } 371 server_client_create(newfd); 372 } 373 374 /* 375 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 376 * event - used to backoff when running out of file descriptors. 377 */ 378 void 379 server_add_accept(int timeout) 380 { 381 struct timeval tv = { timeout, 0 }; 382 383 if (server_fd == -1) 384 return; 385 386 if (event_initialized(&server_ev_accept)) 387 event_del(&server_ev_accept); 388 389 if (timeout == 0) { 390 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 391 NULL); 392 event_add(&server_ev_accept, NULL); 393 } else { 394 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 395 server_accept, NULL); 396 event_add(&server_ev_accept, &tv); 397 } 398 } 399 400 /* Signal handler. */ 401 static void 402 server_signal(int sig) 403 { 404 int fd; 405 406 log_debug("%s: %s", __func__, strsignal(sig)); 407 switch (sig) { 408 case SIGINT: 409 case SIGTERM: 410 server_exit = 1; 411 server_send_exit(); 412 break; 413 case SIGCHLD: 414 server_child_signal(); 415 break; 416 case SIGUSR1: 417 event_del(&server_ev_accept); 418 fd = server_create_socket(server_client_flags, NULL); 419 if (fd != -1) { 420 close(server_fd); 421 server_fd = fd; 422 server_update_socket(); 423 } 424 server_add_accept(0); 425 break; 426 case SIGUSR2: 427 proc_toggle_log(server_proc); 428 break; 429 } 430 } 431 432 /* Handle SIGCHLD. */ 433 static void 434 server_child_signal(void) 435 { 436 int status; 437 pid_t pid; 438 439 for (;;) { 440 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 441 case -1: 442 if (errno == ECHILD) 443 return; 444 fatal("waitpid failed"); 445 case 0: 446 return; 447 } 448 if (WIFSTOPPED(status)) 449 server_child_stopped(pid, status); 450 else if (WIFEXITED(status) || WIFSIGNALED(status)) 451 server_child_exited(pid, status); 452 } 453 } 454 455 /* Handle exited children. */ 456 static void 457 server_child_exited(pid_t pid, int status) 458 { 459 struct window *w, *w1; 460 struct window_pane *wp; 461 462 RB_FOREACH_SAFE(w, windows, &windows, w1) { 463 TAILQ_FOREACH(wp, &w->panes, entry) { 464 if (wp->pid == pid) { 465 wp->status = status; 466 wp->flags |= PANE_STATUSREADY; 467 468 log_debug("%%%u exited", wp->id); 469 wp->flags |= PANE_EXITED; 470 471 if (window_pane_destroy_ready(wp)) 472 server_destroy_pane(wp, 1); 473 break; 474 } 475 } 476 } 477 job_check_died(pid, status); 478 } 479 480 /* Handle stopped children. */ 481 static void 482 server_child_stopped(pid_t pid, int status) 483 { 484 struct window *w; 485 struct window_pane *wp; 486 487 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 488 return; 489 490 RB_FOREACH(w, windows, &windows) { 491 TAILQ_FOREACH(wp, &w->panes, entry) { 492 if (wp->pid == pid) { 493 if (killpg(pid, SIGCONT) != 0) 494 kill(pid, SIGCONT); 495 } 496 } 497 } 498 job_check_died(pid, status); 499 } 500 501 /* Add to message log. */ 502 void 503 server_add_message(const char *fmt, ...) 504 { 505 struct message_entry *msg, *msg1; 506 char *s; 507 va_list ap; 508 u_int limit; 509 510 va_start(ap, fmt); 511 xvasprintf(&s, fmt, ap); 512 va_end(ap); 513 514 log_debug("message: %s", s); 515 516 msg = xcalloc(1, sizeof *msg); 517 gettimeofday(&msg->msg_time, NULL); 518 msg->msg_num = message_next++; 519 msg->msg = s; 520 TAILQ_INSERT_TAIL(&message_log, msg, entry); 521 522 limit = options_get_number(global_options, "message-limit"); 523 TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) { 524 if (msg->msg_num + limit >= message_next) 525 break; 526 free(msg->msg); 527 TAILQ_REMOVE(&message_log, msg, entry); 528 free(msg); 529 } 530 } 531