1 /* $OpenBSD: server.c,v 1.196 2021/02/11 09:39:29 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 fd; 160 sigset_t set, oldset; 161 struct client *c = NULL; 162 char *cause = NULL; 163 164 sigfillset(&set); 165 sigprocmask(SIG_BLOCK, &set, &oldset); 166 167 if (~flags & CLIENT_NOFORK) { 168 if (proc_fork_and_daemon(&fd) != 0) { 169 sigprocmask(SIG_SETMASK, &oldset, NULL); 170 return (fd); 171 } 172 } 173 proc_clear_signals(client, 0); 174 server_client_flags = flags; 175 176 if (event_reinit(base) != 0) 177 fatalx("event_reinit failed"); 178 server_proc = proc_start("server"); 179 180 proc_set_signals(server_proc, server_signal); 181 sigprocmask(SIG_SETMASK, &oldset, NULL); 182 183 if (log_get_level() > 1) 184 tty_create_log(); 185 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 186 "tty ps", NULL) != 0) 187 fatal("pledge failed"); 188 189 input_key_build(); 190 RB_INIT(&windows); 191 RB_INIT(&all_window_panes); 192 TAILQ_INIT(&clients); 193 RB_INIT(&sessions); 194 key_bindings_init(); 195 TAILQ_INIT(&message_log); 196 197 gettimeofday(&start_time, NULL); 198 199 server_fd = server_create_socket(flags, &cause); 200 if (server_fd != -1) 201 server_update_socket(); 202 if (~flags & CLIENT_NOFORK) 203 c = server_client_create(fd); 204 else 205 options_set_number(global_options, "exit-empty", 0); 206 207 if (lockfd >= 0) { 208 unlink(lockfile); 209 free(lockfile); 210 close(lockfd); 211 } 212 213 if (cause != NULL) { 214 if (c != NULL) { 215 cmdq_append(c, cmdq_get_error(cause)); 216 c->flags |= CLIENT_EXIT; 217 } 218 free(cause); 219 } 220 221 server_add_accept(0); 222 proc_loop(server_proc, server_loop); 223 224 job_kill_all(); 225 status_prompt_save_history(); 226 227 exit(0); 228 } 229 230 /* Server loop callback. */ 231 static int 232 server_loop(void) 233 { 234 struct client *c; 235 u_int items; 236 237 do { 238 items = cmdq_next(NULL); 239 TAILQ_FOREACH(c, &clients, entry) { 240 if (c->flags & CLIENT_IDENTIFIED) 241 items += cmdq_next(c); 242 } 243 } while (items != 0); 244 245 server_client_loop(); 246 247 if (!options_get_number(global_options, "exit-empty") && !server_exit) 248 return (0); 249 250 if (!options_get_number(global_options, "exit-unattached")) { 251 if (!RB_EMPTY(&sessions)) 252 return (0); 253 } 254 255 TAILQ_FOREACH(c, &clients, entry) { 256 if (c->session != NULL) 257 return (0); 258 } 259 260 /* 261 * No attached clients therefore want to exit - flush any waiting 262 * clients but don't actually exit until they've gone. 263 */ 264 cmd_wait_for_flush(); 265 if (!TAILQ_EMPTY(&clients)) 266 return (0); 267 268 if (job_still_running()) 269 return (0); 270 271 return (1); 272 } 273 274 /* Exit the server by killing all clients and windows. */ 275 static void 276 server_send_exit(void) 277 { 278 struct client *c, *c1; 279 struct session *s, *s1; 280 281 cmd_wait_for_flush(); 282 283 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 284 if (c->flags & CLIENT_SUSPENDED) 285 server_client_lost(c); 286 else { 287 c->flags |= CLIENT_EXIT; 288 c->exit_type = CLIENT_EXIT_SHUTDOWN; 289 } 290 c->session = NULL; 291 } 292 293 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 294 session_destroy(s, 1, __func__); 295 } 296 297 /* Update socket execute permissions based on whether sessions are attached. */ 298 void 299 server_update_socket(void) 300 { 301 struct session *s; 302 static int last = -1; 303 int n, mode; 304 struct stat sb; 305 306 n = 0; 307 RB_FOREACH(s, sessions, &sessions) { 308 if (s->attached != 0) { 309 n++; 310 break; 311 } 312 } 313 314 if (n != last) { 315 last = n; 316 317 if (stat(socket_path, &sb) != 0) 318 return; 319 mode = sb.st_mode & ACCESSPERMS; 320 if (n != 0) { 321 if (mode & S_IRUSR) 322 mode |= S_IXUSR; 323 if (mode & S_IRGRP) 324 mode |= S_IXGRP; 325 if (mode & S_IROTH) 326 mode |= S_IXOTH; 327 } else 328 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 329 chmod(socket_path, mode); 330 } 331 } 332 333 /* Callback for server socket. */ 334 static void 335 server_accept(int fd, short events, __unused void *data) 336 { 337 struct sockaddr_storage sa; 338 socklen_t slen = sizeof sa; 339 int newfd; 340 341 server_add_accept(0); 342 if (!(events & EV_READ)) 343 return; 344 345 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 346 if (newfd == -1) { 347 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 348 return; 349 if (errno == ENFILE || errno == EMFILE) { 350 /* Delete and don't try again for 1 second. */ 351 server_add_accept(1); 352 return; 353 } 354 fatal("accept failed"); 355 } 356 if (server_exit) { 357 close(newfd); 358 return; 359 } 360 server_client_create(newfd); 361 } 362 363 /* 364 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 365 * event - used to backoff when running out of file descriptors. 366 */ 367 void 368 server_add_accept(int timeout) 369 { 370 struct timeval tv = { timeout, 0 }; 371 372 if (server_fd == -1) 373 return; 374 375 if (event_initialized(&server_ev_accept)) 376 event_del(&server_ev_accept); 377 378 if (timeout == 0) { 379 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 380 NULL); 381 event_add(&server_ev_accept, NULL); 382 } else { 383 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 384 server_accept, NULL); 385 event_add(&server_ev_accept, &tv); 386 } 387 } 388 389 /* Signal handler. */ 390 static void 391 server_signal(int sig) 392 { 393 int fd; 394 395 log_debug("%s: %s", __func__, strsignal(sig)); 396 switch (sig) { 397 case SIGINT: 398 case SIGTERM: 399 server_exit = 1; 400 server_send_exit(); 401 break; 402 case SIGCHLD: 403 server_child_signal(); 404 break; 405 case SIGUSR1: 406 event_del(&server_ev_accept); 407 fd = server_create_socket(server_client_flags, NULL); 408 if (fd != -1) { 409 close(server_fd); 410 server_fd = fd; 411 server_update_socket(); 412 } 413 server_add_accept(0); 414 break; 415 case SIGUSR2: 416 proc_toggle_log(server_proc); 417 break; 418 } 419 } 420 421 /* Handle SIGCHLD. */ 422 static void 423 server_child_signal(void) 424 { 425 int status; 426 pid_t pid; 427 428 for (;;) { 429 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 430 case -1: 431 if (errno == ECHILD) 432 return; 433 fatal("waitpid failed"); 434 case 0: 435 return; 436 } 437 if (WIFSTOPPED(status)) 438 server_child_stopped(pid, status); 439 else if (WIFEXITED(status) || WIFSIGNALED(status)) 440 server_child_exited(pid, status); 441 } 442 } 443 444 /* Handle exited children. */ 445 static void 446 server_child_exited(pid_t pid, int status) 447 { 448 struct window *w, *w1; 449 struct window_pane *wp; 450 451 RB_FOREACH_SAFE(w, windows, &windows, w1) { 452 TAILQ_FOREACH(wp, &w->panes, entry) { 453 if (wp->pid == pid) { 454 wp->status = status; 455 wp->flags |= PANE_STATUSREADY; 456 457 log_debug("%%%u exited", wp->id); 458 wp->flags |= PANE_EXITED; 459 460 if (window_pane_destroy_ready(wp)) 461 server_destroy_pane(wp, 1); 462 break; 463 } 464 } 465 } 466 job_check_died(pid, status); 467 } 468 469 /* Handle stopped children. */ 470 static void 471 server_child_stopped(pid_t pid, int status) 472 { 473 struct window *w; 474 struct window_pane *wp; 475 476 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 477 return; 478 479 RB_FOREACH(w, windows, &windows) { 480 TAILQ_FOREACH(wp, &w->panes, entry) { 481 if (wp->pid == pid) { 482 if (killpg(pid, SIGCONT) != 0) 483 kill(pid, SIGCONT); 484 } 485 } 486 } 487 job_check_died(pid, status); 488 } 489 490 /* Add to message log. */ 491 void 492 server_add_message(const char *fmt, ...) 493 { 494 struct message_entry *msg, *msg1; 495 char *s; 496 va_list ap; 497 u_int limit; 498 499 va_start(ap, fmt); 500 xvasprintf(&s, fmt, ap); 501 va_end(ap); 502 503 log_debug("message: %s", s); 504 505 msg = xcalloc(1, sizeof *msg); 506 gettimeofday(&msg->msg_time, NULL); 507 msg->msg_num = message_next++; 508 msg->msg = s; 509 TAILQ_INSERT_TAIL(&message_log, msg, entry); 510 511 limit = options_get_number(global_options, "message-limit"); 512 TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) { 513 if (msg->msg_num + limit >= message_next) 514 break; 515 free(msg->msg); 516 TAILQ_REMOVE(&message_log, msg, entry); 517 free(msg); 518 } 519 } 520