1 /* $OpenBSD: server.c,v 1.176 2017/07/14 18:49:07 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_create_socket(void); 54 static int server_loop(void); 55 static void server_send_exit(void); 56 static void server_accept(int, short, void *); 57 static void server_signal(int); 58 static void server_child_signal(void); 59 static void server_child_exited(pid_t, int); 60 static void server_child_stopped(pid_t, int); 61 62 /* Set marked pane. */ 63 void 64 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 65 { 66 cmd_find_clear_state(&marked_pane, 0); 67 marked_pane.s = s; 68 marked_pane.wl = wl; 69 marked_pane.w = wl->window; 70 marked_pane.wp = wp; 71 } 72 73 /* Clear marked pane. */ 74 void 75 server_clear_marked(void) 76 { 77 cmd_find_clear_state(&marked_pane, 0); 78 } 79 80 /* Is this the marked pane? */ 81 int 82 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 83 { 84 if (s == NULL || wl == NULL || wp == NULL) 85 return (0); 86 if (marked_pane.s != s || marked_pane.wl != wl) 87 return (0); 88 if (marked_pane.wp != wp) 89 return (0); 90 return (server_check_marked()); 91 } 92 93 /* Check if the marked pane is still valid. */ 94 int 95 server_check_marked(void) 96 { 97 return (cmd_find_valid_state(&marked_pane)); 98 } 99 100 /* Create server socket. */ 101 static int 102 server_create_socket(void) 103 { 104 struct sockaddr_un sa; 105 size_t size; 106 mode_t mask; 107 int fd; 108 109 memset(&sa, 0, sizeof sa); 110 sa.sun_family = AF_UNIX; 111 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 112 if (size >= sizeof sa.sun_path) { 113 errno = ENAMETOOLONG; 114 return (-1); 115 } 116 unlink(sa.sun_path); 117 118 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 119 return (-1); 120 121 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 122 if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) == -1) { 123 close(fd); 124 return (-1); 125 } 126 umask(mask); 127 128 if (listen(fd, 128) == -1) { 129 close(fd); 130 return (-1); 131 } 132 setblocking(fd, 0); 133 134 return (fd); 135 } 136 137 /* Fork new server. */ 138 int 139 server_start(struct tmuxproc *client, struct event_base *base, int lockfd, 140 char *lockfile) 141 { 142 int pair[2]; 143 struct job *job; 144 sigset_t set, oldset; 145 146 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 147 fatal("socketpair failed"); 148 149 sigfillset(&set); 150 sigprocmask(SIG_BLOCK, &set, &oldset); 151 switch (fork()) { 152 case -1: 153 fatal("fork failed"); 154 case 0: 155 break; 156 default: 157 sigprocmask(SIG_SETMASK, &oldset, NULL); 158 close(pair[1]); 159 return (pair[0]); 160 } 161 close(pair[0]); 162 if (daemon(1, 0) != 0) 163 fatal("daemon failed"); 164 proc_clear_signals(client, 0); 165 if (event_reinit(base) != 0) 166 fatalx("event_reinit failed"); 167 server_proc = proc_start("server"); 168 proc_set_signals(server_proc, server_signal); 169 sigprocmask(SIG_SETMASK, &oldset, NULL); 170 171 if (log_get_level() > 1) 172 tty_create_log(); 173 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 174 "tty ps", NULL) != 0) 175 fatal("pledge failed"); 176 177 RB_INIT(&windows); 178 RB_INIT(&all_window_panes); 179 TAILQ_INIT(&clients); 180 RB_INIT(&sessions); 181 RB_INIT(&session_groups); 182 key_bindings_init(); 183 184 gettimeofday(&start_time, NULL); 185 186 server_fd = server_create_socket(); 187 if (server_fd == -1) 188 fatal("couldn't create socket"); 189 server_update_socket(); 190 server_client_create(pair[1]); 191 192 if (lockfd >= 0) { 193 unlink(lockfile); 194 free(lockfile); 195 close(lockfd); 196 } 197 198 start_cfg(); 199 200 server_add_accept(0); 201 202 proc_loop(server_proc, server_loop); 203 204 LIST_FOREACH(job, &all_jobs, entry) { 205 if (job->pid != -1) 206 kill(job->pid, SIGTERM); 207 } 208 209 status_prompt_save_history(); 210 exit(0); 211 } 212 213 /* Server loop callback. */ 214 static int 215 server_loop(void) 216 { 217 struct client *c; 218 u_int items; 219 220 do { 221 items = cmdq_next(NULL); 222 TAILQ_FOREACH(c, &clients, entry) { 223 if (c->flags & CLIENT_IDENTIFIED) 224 items += cmdq_next(c); 225 } 226 } while (items != 0); 227 228 server_client_loop(); 229 230 if (!options_get_number(global_options, "exit-unattached")) { 231 if (!RB_EMPTY(&sessions)) 232 return (0); 233 } 234 235 TAILQ_FOREACH(c, &clients, entry) { 236 if (c->session != NULL) 237 return (0); 238 } 239 240 /* 241 * No attached clients therefore want to exit - flush any waiting 242 * clients but don't actually exit until they've gone. 243 */ 244 cmd_wait_for_flush(); 245 if (!TAILQ_EMPTY(&clients)) 246 return (0); 247 248 return (1); 249 } 250 251 /* Exit the server by killing all clients and windows. */ 252 static void 253 server_send_exit(void) 254 { 255 struct client *c, *c1; 256 struct session *s, *s1; 257 258 cmd_wait_for_flush(); 259 260 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 261 if (c->flags & CLIENT_SUSPENDED) 262 server_client_lost(c); 263 else 264 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 265 c->session = NULL; 266 } 267 268 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 269 session_destroy(s, __func__); 270 } 271 272 /* Update socket execute permissions based on whether sessions are attached. */ 273 void 274 server_update_socket(void) 275 { 276 struct session *s; 277 static int last = -1; 278 int n, mode; 279 struct stat sb; 280 281 n = 0; 282 RB_FOREACH(s, sessions, &sessions) { 283 if (!(s->flags & SESSION_UNATTACHED)) { 284 n++; 285 break; 286 } 287 } 288 289 if (n != last) { 290 last = n; 291 292 if (stat(socket_path, &sb) != 0) 293 return; 294 mode = sb.st_mode & ACCESSPERMS; 295 if (n != 0) { 296 if (mode & S_IRUSR) 297 mode |= S_IXUSR; 298 if (mode & S_IRGRP) 299 mode |= S_IXGRP; 300 if (mode & S_IROTH) 301 mode |= S_IXOTH; 302 } else 303 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 304 chmod(socket_path, mode); 305 } 306 } 307 308 /* Callback for server socket. */ 309 static void 310 server_accept(int fd, short events, __unused void *data) 311 { 312 struct sockaddr_storage sa; 313 socklen_t slen = sizeof sa; 314 int newfd; 315 316 server_add_accept(0); 317 if (!(events & EV_READ)) 318 return; 319 320 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 321 if (newfd == -1) { 322 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 323 return; 324 if (errno == ENFILE || errno == EMFILE) { 325 /* Delete and don't try again for 1 second. */ 326 server_add_accept(1); 327 return; 328 } 329 fatal("accept failed"); 330 } 331 if (server_exit) { 332 close(newfd); 333 return; 334 } 335 server_client_create(newfd); 336 } 337 338 /* 339 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 340 * event - used to backoff when running out of file descriptors. 341 */ 342 void 343 server_add_accept(int timeout) 344 { 345 struct timeval tv = { timeout, 0 }; 346 347 if (event_initialized(&server_ev_accept)) 348 event_del(&server_ev_accept); 349 350 if (timeout == 0) { 351 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 352 NULL); 353 event_add(&server_ev_accept, NULL); 354 } else { 355 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 356 server_accept, NULL); 357 event_add(&server_ev_accept, &tv); 358 } 359 } 360 361 /* Signal handler. */ 362 static void 363 server_signal(int sig) 364 { 365 int fd; 366 367 log_debug("%s: %s", __func__, strsignal(sig)); 368 switch (sig) { 369 case SIGTERM: 370 server_exit = 1; 371 server_send_exit(); 372 break; 373 case SIGCHLD: 374 server_child_signal(); 375 break; 376 case SIGUSR1: 377 event_del(&server_ev_accept); 378 fd = server_create_socket(); 379 if (fd != -1) { 380 close(server_fd); 381 server_fd = fd; 382 server_update_socket(); 383 } 384 server_add_accept(0); 385 break; 386 case SIGUSR2: 387 proc_toggle_log(server_proc); 388 break; 389 } 390 } 391 392 /* Handle SIGCHLD. */ 393 static void 394 server_child_signal(void) 395 { 396 int status; 397 pid_t pid; 398 399 for (;;) { 400 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 401 case -1: 402 if (errno == ECHILD) 403 return; 404 fatal("waitpid failed"); 405 case 0: 406 return; 407 } 408 if (WIFSTOPPED(status)) 409 server_child_stopped(pid, status); 410 else if (WIFEXITED(status) || WIFSIGNALED(status)) 411 server_child_exited(pid, status); 412 } 413 } 414 415 /* Handle exited children. */ 416 static void 417 server_child_exited(pid_t pid, int status) 418 { 419 struct window *w, *w1; 420 struct window_pane *wp; 421 struct job *job; 422 423 RB_FOREACH_SAFE(w, windows, &windows, w1) { 424 TAILQ_FOREACH(wp, &w->panes, entry) { 425 if (wp->pid == pid) { 426 wp->status = status; 427 428 log_debug("%%%u exited", wp->id); 429 wp->flags |= PANE_EXITED; 430 431 if (window_pane_destroy_ready(wp)) 432 server_destroy_pane(wp, 1); 433 break; 434 } 435 } 436 } 437 438 LIST_FOREACH(job, &all_jobs, entry) { 439 if (pid == job->pid) { 440 job_died(job, status); /* might free job */ 441 break; 442 } 443 } 444 } 445 446 /* Handle stopped children. */ 447 static void 448 server_child_stopped(pid_t pid, int status) 449 { 450 struct window *w; 451 struct window_pane *wp; 452 453 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 454 return; 455 456 RB_FOREACH(w, windows, &windows) { 457 TAILQ_FOREACH(wp, &w->panes, entry) { 458 if (wp->pid == pid) { 459 if (killpg(pid, SIGCONT) != 0) 460 kill(pid, SIGCONT); 461 } 462 } 463 } 464 } 465