1 /* $OpenBSD: server.c,v 1.185 2019/05/20 11:46:06 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 /* 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 start_cfg(); 214 server_add_accept(0); 215 216 proc_loop(server_proc, server_loop); 217 218 job_kill_all(); 219 status_prompt_save_history(); 220 221 exit(0); 222 } 223 224 /* Server loop callback. */ 225 static int 226 server_loop(void) 227 { 228 struct client *c; 229 u_int items; 230 231 do { 232 items = cmdq_next(NULL); 233 TAILQ_FOREACH(c, &clients, entry) { 234 if (c->flags & CLIENT_IDENTIFIED) 235 items += cmdq_next(c); 236 } 237 } while (items != 0); 238 239 server_client_loop(); 240 241 if (!options_get_number(global_options, "exit-empty") && !server_exit) 242 return (0); 243 244 if (!options_get_number(global_options, "exit-unattached")) { 245 if (!RB_EMPTY(&sessions)) 246 return (0); 247 } 248 249 TAILQ_FOREACH(c, &clients, entry) { 250 if (c->session != NULL) 251 return (0); 252 } 253 254 /* 255 * No attached clients therefore want to exit - flush any waiting 256 * clients but don't actually exit until they've gone. 257 */ 258 cmd_wait_for_flush(); 259 if (!TAILQ_EMPTY(&clients)) 260 return (0); 261 262 if (job_still_running()) 263 return (0); 264 265 return (1); 266 } 267 268 /* Exit the server by killing all clients and windows. */ 269 static void 270 server_send_exit(void) 271 { 272 struct client *c, *c1; 273 struct session *s, *s1; 274 275 cmd_wait_for_flush(); 276 277 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 278 if (c->flags & CLIENT_SUSPENDED) 279 server_client_lost(c); 280 else { 281 if (c->flags & CLIENT_ATTACHED) 282 notify_client("client-detached", c); 283 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 284 } 285 c->session = NULL; 286 } 287 288 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 289 session_destroy(s, 1, __func__); 290 } 291 292 /* Update socket execute permissions based on whether sessions are attached. */ 293 void 294 server_update_socket(void) 295 { 296 struct session *s; 297 static int last = -1; 298 int n, mode; 299 struct stat sb; 300 301 n = 0; 302 RB_FOREACH(s, sessions, &sessions) { 303 if (s->attached != 0) { 304 n++; 305 break; 306 } 307 } 308 309 if (n != last) { 310 last = n; 311 312 if (stat(socket_path, &sb) != 0) 313 return; 314 mode = sb.st_mode & ACCESSPERMS; 315 if (n != 0) { 316 if (mode & S_IRUSR) 317 mode |= S_IXUSR; 318 if (mode & S_IRGRP) 319 mode |= S_IXGRP; 320 if (mode & S_IROTH) 321 mode |= S_IXOTH; 322 } else 323 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 324 chmod(socket_path, mode); 325 } 326 } 327 328 /* Callback for server socket. */ 329 static void 330 server_accept(int fd, short events, __unused void *data) 331 { 332 struct sockaddr_storage sa; 333 socklen_t slen = sizeof sa; 334 int newfd; 335 336 server_add_accept(0); 337 if (!(events & EV_READ)) 338 return; 339 340 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 341 if (newfd == -1) { 342 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 343 return; 344 if (errno == ENFILE || errno == EMFILE) { 345 /* Delete and don't try again for 1 second. */ 346 server_add_accept(1); 347 return; 348 } 349 fatal("accept failed"); 350 } 351 if (server_exit) { 352 close(newfd); 353 return; 354 } 355 server_client_create(newfd); 356 } 357 358 /* 359 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 360 * event - used to backoff when running out of file descriptors. 361 */ 362 void 363 server_add_accept(int timeout) 364 { 365 struct timeval tv = { timeout, 0 }; 366 367 if (event_initialized(&server_ev_accept)) 368 event_del(&server_ev_accept); 369 370 if (timeout == 0) { 371 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 372 NULL); 373 event_add(&server_ev_accept, NULL); 374 } else { 375 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 376 server_accept, NULL); 377 event_add(&server_ev_accept, &tv); 378 } 379 } 380 381 /* Signal handler. */ 382 static void 383 server_signal(int sig) 384 { 385 int fd; 386 387 log_debug("%s: %s", __func__, strsignal(sig)); 388 switch (sig) { 389 case SIGTERM: 390 server_exit = 1; 391 server_send_exit(); 392 break; 393 case SIGCHLD: 394 server_child_signal(); 395 break; 396 case SIGUSR1: 397 event_del(&server_ev_accept); 398 fd = server_create_socket(NULL); 399 if (fd != -1) { 400 close(server_fd); 401 server_fd = fd; 402 server_update_socket(); 403 } 404 server_add_accept(0); 405 break; 406 case SIGUSR2: 407 proc_toggle_log(server_proc); 408 break; 409 } 410 } 411 412 /* Handle SIGCHLD. */ 413 static void 414 server_child_signal(void) 415 { 416 int status; 417 pid_t pid; 418 419 for (;;) { 420 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 421 case -1: 422 if (errno == ECHILD) 423 return; 424 fatal("waitpid failed"); 425 case 0: 426 return; 427 } 428 if (WIFSTOPPED(status)) 429 server_child_stopped(pid, status); 430 else if (WIFEXITED(status) || WIFSIGNALED(status)) 431 server_child_exited(pid, status); 432 } 433 } 434 435 /* Handle exited children. */ 436 static void 437 server_child_exited(pid_t pid, int status) 438 { 439 struct window *w, *w1; 440 struct window_pane *wp; 441 442 RB_FOREACH_SAFE(w, windows, &windows, w1) { 443 TAILQ_FOREACH(wp, &w->panes, entry) { 444 if (wp->pid == pid) { 445 wp->status = status; 446 wp->flags |= PANE_STATUSREADY; 447 448 log_debug("%%%u exited", wp->id); 449 wp->flags |= PANE_EXITED; 450 451 if (window_pane_destroy_ready(wp)) 452 server_destroy_pane(wp, 1); 453 break; 454 } 455 } 456 } 457 job_check_died(pid, status); 458 } 459 460 /* Handle stopped children. */ 461 static void 462 server_child_stopped(pid_t pid, int status) 463 { 464 struct window *w; 465 struct window_pane *wp; 466 467 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 468 return; 469 470 RB_FOREACH(w, windows, &windows) { 471 TAILQ_FOREACH(wp, &w->panes, entry) { 472 if (wp->pid == pid) { 473 if (killpg(pid, SIGCONT) != 0) 474 kill(pid, SIGCONT); 475 } 476 } 477 } 478 } 479