1 /* $OpenBSD: server.c,v 1.187 2019/06/20 06:51:36 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 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 /* Fork new server. */ 148 int 149 server_start(struct tmuxproc *client, struct event_base *base, int lockfd, 150 char *lockfile) 151 { 152 int pair[2]; 153 sigset_t set, oldset; 154 struct client *c; 155 char *cause = NULL; 156 157 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 158 fatal("socketpair failed"); 159 160 sigfillset(&set); 161 sigprocmask(SIG_BLOCK, &set, &oldset); 162 switch (fork()) { 163 case -1: 164 fatal("fork failed"); 165 case 0: 166 break; 167 default: 168 sigprocmask(SIG_SETMASK, &oldset, NULL); 169 close(pair[1]); 170 return (pair[0]); 171 } 172 close(pair[0]); 173 if (daemon(1, 0) != 0) 174 fatal("daemon failed"); 175 proc_clear_signals(client, 0); 176 if (event_reinit(base) != 0) 177 fatalx("event_reinit failed"); 178 server_proc = proc_start("server"); 179 proc_set_signals(server_proc, server_signal); 180 sigprocmask(SIG_SETMASK, &oldset, NULL); 181 182 if (log_get_level() > 1) 183 tty_create_log(); 184 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 185 "tty ps", NULL) != 0) 186 fatal("pledge failed"); 187 188 RB_INIT(&windows); 189 RB_INIT(&all_window_panes); 190 TAILQ_INIT(&clients); 191 RB_INIT(&sessions); 192 key_bindings_init(); 193 194 gettimeofday(&start_time, NULL); 195 196 server_fd = server_create_socket(&cause); 197 if (server_fd != -1) 198 server_update_socket(); 199 c = server_client_create(pair[1]); 200 201 if (lockfd >= 0) { 202 unlink(lockfile); 203 free(lockfile); 204 close(lockfd); 205 } 206 207 if (cause != NULL) { 208 cmdq_append(c, cmdq_get_error(cause)); 209 free(cause); 210 c->flags |= CLIENT_EXIT; 211 } 212 213 server_add_accept(0); 214 proc_loop(server_proc, server_loop); 215 216 job_kill_all(); 217 status_prompt_save_history(); 218 219 exit(0); 220 } 221 222 /* Server loop callback. */ 223 static int 224 server_loop(void) 225 { 226 struct client *c; 227 u_int items; 228 229 do { 230 items = cmdq_next(NULL); 231 TAILQ_FOREACH(c, &clients, entry) { 232 if (c->flags & CLIENT_IDENTIFIED) 233 items += cmdq_next(c); 234 } 235 } while (items != 0); 236 237 server_client_loop(); 238 239 if (!options_get_number(global_options, "exit-empty") && !server_exit) 240 return (0); 241 242 if (!options_get_number(global_options, "exit-unattached")) { 243 if (!RB_EMPTY(&sessions)) 244 return (0); 245 } 246 247 TAILQ_FOREACH(c, &clients, entry) { 248 if (c->session != NULL) 249 return (0); 250 } 251 252 /* 253 * No attached clients therefore want to exit - flush any waiting 254 * clients but don't actually exit until they've gone. 255 */ 256 cmd_wait_for_flush(); 257 if (!TAILQ_EMPTY(&clients)) 258 return (0); 259 260 if (job_still_running()) 261 return (0); 262 263 return (1); 264 } 265 266 /* Exit the server by killing all clients and windows. */ 267 static void 268 server_send_exit(void) 269 { 270 struct client *c, *c1; 271 struct session *s, *s1; 272 273 cmd_wait_for_flush(); 274 275 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 276 if (c->flags & CLIENT_SUSPENDED) 277 server_client_lost(c); 278 else { 279 if (c->flags & CLIENT_ATTACHED) 280 notify_client("client-detached", c); 281 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 282 } 283 c->session = NULL; 284 } 285 286 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 287 session_destroy(s, 1, __func__); 288 } 289 290 /* Update socket execute permissions based on whether sessions are attached. */ 291 void 292 server_update_socket(void) 293 { 294 struct session *s; 295 static int last = -1; 296 int n, mode; 297 struct stat sb; 298 299 n = 0; 300 RB_FOREACH(s, sessions, &sessions) { 301 if (s->attached != 0) { 302 n++; 303 break; 304 } 305 } 306 307 if (n != last) { 308 last = n; 309 310 if (stat(socket_path, &sb) != 0) 311 return; 312 mode = sb.st_mode & ACCESSPERMS; 313 if (n != 0) { 314 if (mode & S_IRUSR) 315 mode |= S_IXUSR; 316 if (mode & S_IRGRP) 317 mode |= S_IXGRP; 318 if (mode & S_IROTH) 319 mode |= S_IXOTH; 320 } else 321 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 322 chmod(socket_path, mode); 323 } 324 } 325 326 /* Callback for server socket. */ 327 static void 328 server_accept(int fd, short events, __unused void *data) 329 { 330 struct sockaddr_storage sa; 331 socklen_t slen = sizeof sa; 332 int newfd; 333 334 server_add_accept(0); 335 if (!(events & EV_READ)) 336 return; 337 338 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 339 if (newfd == -1) { 340 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 341 return; 342 if (errno == ENFILE || errno == EMFILE) { 343 /* Delete and don't try again for 1 second. */ 344 server_add_accept(1); 345 return; 346 } 347 fatal("accept failed"); 348 } 349 if (server_exit) { 350 close(newfd); 351 return; 352 } 353 server_client_create(newfd); 354 } 355 356 /* 357 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 358 * event - used to backoff when running out of file descriptors. 359 */ 360 void 361 server_add_accept(int timeout) 362 { 363 struct timeval tv = { timeout, 0 }; 364 365 if (server_fd == -1) 366 return; 367 368 if (event_initialized(&server_ev_accept)) 369 event_del(&server_ev_accept); 370 371 if (timeout == 0) { 372 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 373 NULL); 374 event_add(&server_ev_accept, NULL); 375 } else { 376 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 377 server_accept, NULL); 378 event_add(&server_ev_accept, &tv); 379 } 380 } 381 382 /* Signal handler. */ 383 static void 384 server_signal(int sig) 385 { 386 int fd; 387 388 log_debug("%s: %s", __func__, strsignal(sig)); 389 switch (sig) { 390 case SIGTERM: 391 server_exit = 1; 392 server_send_exit(); 393 break; 394 case SIGCHLD: 395 server_child_signal(); 396 break; 397 case SIGUSR1: 398 event_del(&server_ev_accept); 399 fd = server_create_socket(NULL); 400 if (fd != -1) { 401 close(server_fd); 402 server_fd = fd; 403 server_update_socket(); 404 } 405 server_add_accept(0); 406 break; 407 case SIGUSR2: 408 proc_toggle_log(server_proc); 409 break; 410 } 411 } 412 413 /* Handle SIGCHLD. */ 414 static void 415 server_child_signal(void) 416 { 417 int status; 418 pid_t pid; 419 420 for (;;) { 421 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 422 case -1: 423 if (errno == ECHILD) 424 return; 425 fatal("waitpid failed"); 426 case 0: 427 return; 428 } 429 if (WIFSTOPPED(status)) 430 server_child_stopped(pid, status); 431 else if (WIFEXITED(status) || WIFSIGNALED(status)) 432 server_child_exited(pid, status); 433 } 434 } 435 436 /* Handle exited children. */ 437 static void 438 server_child_exited(pid_t pid, int status) 439 { 440 struct window *w, *w1; 441 struct window_pane *wp; 442 443 RB_FOREACH_SAFE(w, windows, &windows, w1) { 444 TAILQ_FOREACH(wp, &w->panes, entry) { 445 if (wp->pid == pid) { 446 wp->status = status; 447 wp->flags |= PANE_STATUSREADY; 448 449 log_debug("%%%u exited", wp->id); 450 wp->flags |= PANE_EXITED; 451 452 if (window_pane_destroy_ready(wp)) 453 server_destroy_pane(wp, 1); 454 break; 455 } 456 } 457 } 458 job_check_died(pid, status); 459 } 460 461 /* Handle stopped children. */ 462 static void 463 server_child_stopped(pid_t pid, int status) 464 { 465 struct window *w; 466 struct window_pane *wp; 467 468 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 469 return; 470 471 RB_FOREACH(w, windows, &windows) { 472 TAILQ_FOREACH(wp, &w->panes, entry) { 473 if (wp->pid == pid) { 474 if (killpg(pid, SIGCONT) != 0) 475 kill(pid, SIGCONT); 476 } 477 } 478 } 479 } 480