1 /* $OpenBSD: server.c,v 1.184 2019/04/17 14:37:48 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; 48 static int server_exit; 49 static struct event server_ev_accept; 50 51 struct cmd_find_state marked_pane; 52 53 static int server_loop(void); 54 static void server_send_exit(void); 55 static void server_accept(int, short, void *); 56 static void server_signal(int); 57 static void server_child_signal(void); 58 static void server_child_exited(pid_t, int); 59 static void server_child_stopped(pid_t, int); 60 61 /* Set marked pane. */ 62 void 63 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 64 { 65 cmd_find_clear_state(&marked_pane, 0); 66 marked_pane.s = s; 67 marked_pane.wl = wl; 68 marked_pane.w = wl->window; 69 marked_pane.wp = wp; 70 } 71 72 /* Clear marked pane. */ 73 void 74 server_clear_marked(void) 75 { 76 cmd_find_clear_state(&marked_pane, 0); 77 } 78 79 /* Is this the marked pane? */ 80 int 81 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 82 { 83 if (s == NULL || wl == NULL || wp == NULL) 84 return (0); 85 if (marked_pane.s != s || marked_pane.wl != wl) 86 return (0); 87 if (marked_pane.wp != wp) 88 return (0); 89 return (server_check_marked()); 90 } 91 92 /* Check if the marked pane is still valid. */ 93 int 94 server_check_marked(void) 95 { 96 return (cmd_find_valid_state(&marked_pane)); 97 } 98 99 /* Create server socket. */ 100 static int 101 server_create_socket(char **cause) 102 { 103 struct sockaddr_un sa; 104 size_t size; 105 mode_t mask; 106 int fd, saved_errno; 107 108 memset(&sa, 0, sizeof sa); 109 sa.sun_family = AF_UNIX; 110 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 111 if (size >= sizeof sa.sun_path) { 112 errno = ENAMETOOLONG; 113 goto fail; 114 } 115 unlink(sa.sun_path); 116 117 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 118 goto fail; 119 120 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 121 if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 122 saved_errno = errno; 123 close(fd); 124 errno = saved_errno; 125 goto fail; 126 } 127 umask(mask); 128 129 if (listen(fd, 128) == -1) { 130 saved_errno = errno; 131 close(fd); 132 errno = saved_errno; 133 goto fail; 134 } 135 setblocking(fd, 0); 136 137 return (fd); 138 139 fail: 140 if (cause != NULL) { 141 xasprintf(cause, "error creating %s (%s)", socket_path, 142 strerror(errno)); 143 } 144 return (-1); 145 } 146 147 /* Server error callback. */ 148 static enum cmd_retval 149 server_start_error(struct cmdq_item *item, void *data) 150 { 151 char *error = data; 152 153 cmdq_error(item, "%s", error); 154 free(error); 155 156 return (CMD_RETURN_NORMAL); 157 } 158 159 /* Fork new server. */ 160 int 161 server_start(struct tmuxproc *client, struct event_base *base, int lockfd, 162 char *lockfile) 163 { 164 int pair[2]; 165 sigset_t set, oldset; 166 struct client *c; 167 char *cause = NULL; 168 169 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 170 fatal("socketpair failed"); 171 172 sigfillset(&set); 173 sigprocmask(SIG_BLOCK, &set, &oldset); 174 switch (fork()) { 175 case -1: 176 fatal("fork failed"); 177 case 0: 178 break; 179 default: 180 sigprocmask(SIG_SETMASK, &oldset, NULL); 181 close(pair[1]); 182 return (pair[0]); 183 } 184 close(pair[0]); 185 if (daemon(1, 0) != 0) 186 fatal("daemon failed"); 187 proc_clear_signals(client, 0); 188 if (event_reinit(base) != 0) 189 fatalx("event_reinit failed"); 190 server_proc = proc_start("server"); 191 proc_set_signals(server_proc, server_signal); 192 sigprocmask(SIG_SETMASK, &oldset, NULL); 193 194 if (log_get_level() > 1) 195 tty_create_log(); 196 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 197 "tty ps", NULL) != 0) 198 fatal("pledge failed"); 199 200 RB_INIT(&windows); 201 RB_INIT(&all_window_panes); 202 TAILQ_INIT(&clients); 203 RB_INIT(&sessions); 204 key_bindings_init(); 205 206 gettimeofday(&start_time, NULL); 207 208 server_fd = server_create_socket(&cause); 209 if (server_fd != -1) 210 server_update_socket(); 211 c = server_client_create(pair[1]); 212 213 if (lockfd >= 0) { 214 unlink(lockfile); 215 free(lockfile); 216 close(lockfd); 217 } 218 219 if (cause != NULL) { 220 cmdq_append(c, cmdq_get_callback(server_start_error, cause)); 221 c->flags |= CLIENT_EXIT; 222 } 223 224 start_cfg(); 225 server_add_accept(0); 226 227 proc_loop(server_proc, server_loop); 228 229 job_kill_all(); 230 status_prompt_save_history(); 231 232 exit(0); 233 } 234 235 /* Server loop callback. */ 236 static int 237 server_loop(void) 238 { 239 struct client *c; 240 u_int items; 241 242 do { 243 items = cmdq_next(NULL); 244 TAILQ_FOREACH(c, &clients, entry) { 245 if (c->flags & CLIENT_IDENTIFIED) 246 items += cmdq_next(c); 247 } 248 } while (items != 0); 249 250 server_client_loop(); 251 252 if (!options_get_number(global_options, "exit-empty") && !server_exit) 253 return (0); 254 255 if (!options_get_number(global_options, "exit-unattached")) { 256 if (!RB_EMPTY(&sessions)) 257 return (0); 258 } 259 260 TAILQ_FOREACH(c, &clients, entry) { 261 if (c->session != NULL) 262 return (0); 263 } 264 265 /* 266 * No attached clients therefore want to exit - flush any waiting 267 * clients but don't actually exit until they've gone. 268 */ 269 cmd_wait_for_flush(); 270 if (!TAILQ_EMPTY(&clients)) 271 return (0); 272 273 if (job_still_running()) 274 return (0); 275 276 return (1); 277 } 278 279 /* Exit the server by killing all clients and windows. */ 280 static void 281 server_send_exit(void) 282 { 283 struct client *c, *c1; 284 struct session *s, *s1; 285 286 cmd_wait_for_flush(); 287 288 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 289 if (c->flags & CLIENT_SUSPENDED) 290 server_client_lost(c); 291 else { 292 if (c->flags & CLIENT_ATTACHED) 293 notify_client("client-detached", c); 294 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 295 } 296 c->session = NULL; 297 } 298 299 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 300 session_destroy(s, 1, __func__); 301 } 302 303 /* Update socket execute permissions based on whether sessions are attached. */ 304 void 305 server_update_socket(void) 306 { 307 struct session *s; 308 static int last = -1; 309 int n, mode; 310 struct stat sb; 311 312 n = 0; 313 RB_FOREACH(s, sessions, &sessions) { 314 if (s->attached != 0) { 315 n++; 316 break; 317 } 318 } 319 320 if (n != last) { 321 last = n; 322 323 if (stat(socket_path, &sb) != 0) 324 return; 325 mode = sb.st_mode & ACCESSPERMS; 326 if (n != 0) { 327 if (mode & S_IRUSR) 328 mode |= S_IXUSR; 329 if (mode & S_IRGRP) 330 mode |= S_IXGRP; 331 if (mode & S_IROTH) 332 mode |= S_IXOTH; 333 } else 334 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 335 chmod(socket_path, mode); 336 } 337 } 338 339 /* Callback for server socket. */ 340 static void 341 server_accept(int fd, short events, __unused void *data) 342 { 343 struct sockaddr_storage sa; 344 socklen_t slen = sizeof sa; 345 int newfd; 346 347 server_add_accept(0); 348 if (!(events & EV_READ)) 349 return; 350 351 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 352 if (newfd == -1) { 353 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 354 return; 355 if (errno == ENFILE || errno == EMFILE) { 356 /* Delete and don't try again for 1 second. */ 357 server_add_accept(1); 358 return; 359 } 360 fatal("accept failed"); 361 } 362 if (server_exit) { 363 close(newfd); 364 return; 365 } 366 server_client_create(newfd); 367 } 368 369 /* 370 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 371 * event - used to backoff when running out of file descriptors. 372 */ 373 void 374 server_add_accept(int timeout) 375 { 376 struct timeval tv = { timeout, 0 }; 377 378 if (event_initialized(&server_ev_accept)) 379 event_del(&server_ev_accept); 380 381 if (timeout == 0) { 382 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 383 NULL); 384 event_add(&server_ev_accept, NULL); 385 } else { 386 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 387 server_accept, NULL); 388 event_add(&server_ev_accept, &tv); 389 } 390 } 391 392 /* Signal handler. */ 393 static void 394 server_signal(int sig) 395 { 396 int fd; 397 398 log_debug("%s: %s", __func__, strsignal(sig)); 399 switch (sig) { 400 case SIGTERM: 401 server_exit = 1; 402 server_send_exit(); 403 break; 404 case SIGCHLD: 405 server_child_signal(); 406 break; 407 case SIGUSR1: 408 event_del(&server_ev_accept); 409 fd = server_create_socket(NULL); 410 if (fd != -1) { 411 close(server_fd); 412 server_fd = fd; 413 server_update_socket(); 414 } 415 server_add_accept(0); 416 break; 417 case SIGUSR2: 418 proc_toggle_log(server_proc); 419 break; 420 } 421 } 422 423 /* Handle SIGCHLD. */ 424 static void 425 server_child_signal(void) 426 { 427 int status; 428 pid_t pid; 429 430 for (;;) { 431 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 432 case -1: 433 if (errno == ECHILD) 434 return; 435 fatal("waitpid failed"); 436 case 0: 437 return; 438 } 439 if (WIFSTOPPED(status)) 440 server_child_stopped(pid, status); 441 else if (WIFEXITED(status) || WIFSIGNALED(status)) 442 server_child_exited(pid, status); 443 } 444 } 445 446 /* Handle exited children. */ 447 static void 448 server_child_exited(pid_t pid, int status) 449 { 450 struct window *w, *w1; 451 struct window_pane *wp; 452 453 RB_FOREACH_SAFE(w, windows, &windows, w1) { 454 TAILQ_FOREACH(wp, &w->panes, entry) { 455 if (wp->pid == pid) { 456 wp->status = status; 457 wp->flags |= PANE_STATUSREADY; 458 459 log_debug("%%%u exited", wp->id); 460 wp->flags |= PANE_EXITED; 461 462 if (window_pane_destroy_ready(wp)) 463 server_destroy_pane(wp, 1); 464 break; 465 } 466 } 467 } 468 job_check_died(pid, status); 469 } 470 471 /* Handle stopped children. */ 472 static void 473 server_child_stopped(pid_t pid, int status) 474 { 475 struct window *w; 476 struct window_pane *wp; 477 478 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 479 return; 480 481 RB_FOREACH(w, windows, &windows) { 482 TAILQ_FOREACH(wp, &w->panes, entry) { 483 if (wp->pid == pid) { 484 if (killpg(pid, SIGCONT) != 0) 485 kill(pid, SIGCONT); 486 } 487 } 488 } 489 } 490