1 /* $OpenBSD: server.c,v 1.178 2017/12/19 15:00:39 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 struct job *job; 166 sigset_t set, oldset; 167 struct client *c; 168 char *cause = NULL; 169 170 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 171 fatal("socketpair failed"); 172 173 sigfillset(&set); 174 sigprocmask(SIG_BLOCK, &set, &oldset); 175 switch (fork()) { 176 case -1: 177 fatal("fork failed"); 178 case 0: 179 break; 180 default: 181 sigprocmask(SIG_SETMASK, &oldset, NULL); 182 close(pair[1]); 183 return (pair[0]); 184 } 185 close(pair[0]); 186 if (daemon(1, 0) != 0) 187 fatal("daemon failed"); 188 proc_clear_signals(client, 0); 189 if (event_reinit(base) != 0) 190 fatalx("event_reinit failed"); 191 server_proc = proc_start("server"); 192 proc_set_signals(server_proc, server_signal); 193 sigprocmask(SIG_SETMASK, &oldset, NULL); 194 195 if (log_get_level() > 1) 196 tty_create_log(); 197 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 198 "tty ps", NULL) != 0) 199 fatal("pledge failed"); 200 201 RB_INIT(&windows); 202 RB_INIT(&all_window_panes); 203 TAILQ_INIT(&clients); 204 RB_INIT(&sessions); 205 RB_INIT(&session_groups); 206 key_bindings_init(); 207 208 gettimeofday(&start_time, NULL); 209 210 server_fd = server_create_socket(&cause); 211 if (server_fd != -1) 212 server_update_socket(); 213 c = server_client_create(pair[1]); 214 215 if (lockfd >= 0) { 216 unlink(lockfile); 217 free(lockfile); 218 close(lockfd); 219 } 220 221 if (cause != NULL) { 222 cmdq_append(c, cmdq_get_callback(server_start_error, cause)); 223 c->flags |= CLIENT_EXIT; 224 } 225 226 start_cfg(); 227 228 server_add_accept(0); 229 230 proc_loop(server_proc, server_loop); 231 232 LIST_FOREACH(job, &all_jobs, entry) { 233 if (job->pid != -1) 234 kill(job->pid, SIGTERM); 235 } 236 237 status_prompt_save_history(); 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-unattached")) { 259 if (!RB_EMPTY(&sessions)) 260 return (0); 261 } 262 263 TAILQ_FOREACH(c, &clients, entry) { 264 if (c->session != NULL) 265 return (0); 266 } 267 268 /* 269 * No attached clients therefore want to exit - flush any waiting 270 * clients but don't actually exit until they've gone. 271 */ 272 cmd_wait_for_flush(); 273 if (!TAILQ_EMPTY(&clients)) 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 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 293 c->session = NULL; 294 } 295 296 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 297 session_destroy(s, __func__); 298 } 299 300 /* Update socket execute permissions based on whether sessions are attached. */ 301 void 302 server_update_socket(void) 303 { 304 struct session *s; 305 static int last = -1; 306 int n, mode; 307 struct stat sb; 308 309 n = 0; 310 RB_FOREACH(s, sessions, &sessions) { 311 if (!(s->flags & SESSION_UNATTACHED)) { 312 n++; 313 break; 314 } 315 } 316 317 if (n != last) { 318 last = n; 319 320 if (stat(socket_path, &sb) != 0) 321 return; 322 mode = sb.st_mode & ACCESSPERMS; 323 if (n != 0) { 324 if (mode & S_IRUSR) 325 mode |= S_IXUSR; 326 if (mode & S_IRGRP) 327 mode |= S_IXGRP; 328 if (mode & S_IROTH) 329 mode |= S_IXOTH; 330 } else 331 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 332 chmod(socket_path, mode); 333 } 334 } 335 336 /* Callback for server socket. */ 337 static void 338 server_accept(int fd, short events, __unused void *data) 339 { 340 struct sockaddr_storage sa; 341 socklen_t slen = sizeof sa; 342 int newfd; 343 344 server_add_accept(0); 345 if (!(events & EV_READ)) 346 return; 347 348 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 349 if (newfd == -1) { 350 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 351 return; 352 if (errno == ENFILE || errno == EMFILE) { 353 /* Delete and don't try again for 1 second. */ 354 server_add_accept(1); 355 return; 356 } 357 fatal("accept failed"); 358 } 359 if (server_exit) { 360 close(newfd); 361 return; 362 } 363 server_client_create(newfd); 364 } 365 366 /* 367 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 368 * event - used to backoff when running out of file descriptors. 369 */ 370 void 371 server_add_accept(int timeout) 372 { 373 struct timeval tv = { timeout, 0 }; 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 SIGTERM: 398 server_exit = 1; 399 server_send_exit(); 400 break; 401 case SIGCHLD: 402 server_child_signal(); 403 break; 404 case SIGUSR1: 405 event_del(&server_ev_accept); 406 fd = server_create_socket(NULL); 407 if (fd != -1) { 408 close(server_fd); 409 server_fd = fd; 410 server_update_socket(); 411 } 412 server_add_accept(0); 413 break; 414 case SIGUSR2: 415 proc_toggle_log(server_proc); 416 break; 417 } 418 } 419 420 /* Handle SIGCHLD. */ 421 static void 422 server_child_signal(void) 423 { 424 int status; 425 pid_t pid; 426 427 for (;;) { 428 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 429 case -1: 430 if (errno == ECHILD) 431 return; 432 fatal("waitpid failed"); 433 case 0: 434 return; 435 } 436 if (WIFSTOPPED(status)) 437 server_child_stopped(pid, status); 438 else if (WIFEXITED(status) || WIFSIGNALED(status)) 439 server_child_exited(pid, status); 440 } 441 } 442 443 /* Handle exited children. */ 444 static void 445 server_child_exited(pid_t pid, int status) 446 { 447 struct window *w, *w1; 448 struct window_pane *wp; 449 struct job *job; 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 } 466 467 LIST_FOREACH(job, &all_jobs, entry) { 468 if (pid == job->pid) { 469 job_died(job, status); /* might free job */ 470 break; 471 } 472 } 473 } 474 475 /* Handle stopped children. */ 476 static void 477 server_child_stopped(pid_t pid, int status) 478 { 479 struct window *w; 480 struct window_pane *wp; 481 482 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 483 return; 484 485 RB_FOREACH(w, windows, &windows) { 486 TAILQ_FOREACH(wp, &w->panes, entry) { 487 if (wp->pid == pid) { 488 if (killpg(pid, SIGCONT) != 0) 489 kill(pid, SIGCONT); 490 } 491 } 492 } 493 } 494