1 /* $OpenBSD: server.c,v 1.164 2016/11/12 19:04:41 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, NULL, 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, NULL, 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 return (-1); 124 umask(mask); 125 126 if (listen(fd, 128) == -1) 127 return (-1); 128 setblocking(fd, 0); 129 130 return (fd); 131 } 132 133 /* Fork new server. */ 134 int 135 server_start(struct event_base *base, int lockfd, char *lockfile) 136 { 137 int pair[2]; 138 139 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 140 fatal("socketpair failed"); 141 142 server_proc = proc_start("server", base, 1, server_signal); 143 if (server_proc == NULL) { 144 close(pair[1]); 145 return (pair[0]); 146 } 147 close(pair[0]); 148 149 if (log_get_level() > 3) 150 tty_create_log(); 151 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 152 "tty ps", NULL) != 0) 153 fatal("pledge failed"); 154 155 RB_INIT(&windows); 156 RB_INIT(&all_window_panes); 157 TAILQ_INIT(&clients); 158 RB_INIT(&sessions); 159 TAILQ_INIT(&session_groups); 160 mode_key_init_trees(); 161 key_bindings_init(); 162 163 gettimeofday(&start_time, NULL); 164 165 server_fd = server_create_socket(); 166 if (server_fd == -1) 167 fatal("couldn't create socket"); 168 server_update_socket(); 169 server_client_create(pair[1]); 170 171 if (lockfd >= 0) { 172 unlink(lockfile); 173 free(lockfile); 174 close(lockfd); 175 } 176 177 start_cfg(); 178 179 status_prompt_load_history(); 180 181 server_add_accept(0); 182 183 proc_loop(server_proc, server_loop); 184 status_prompt_save_history(); 185 exit(0); 186 } 187 188 /* Server loop callback. */ 189 static int 190 server_loop(void) 191 { 192 struct client *c; 193 u_int items; 194 195 do { 196 items = cmdq_next(NULL); 197 TAILQ_FOREACH(c, &clients, entry) { 198 if (c->flags & CLIENT_IDENTIFIED) 199 items += cmdq_next(c); 200 } 201 } while (items != 0); 202 203 server_client_loop(); 204 205 if (!options_get_number(global_options, "exit-unattached")) { 206 if (!RB_EMPTY(&sessions)) 207 return (0); 208 } 209 210 TAILQ_FOREACH(c, &clients, entry) { 211 if (c->session != NULL) 212 return (0); 213 } 214 215 /* 216 * No attached clients therefore want to exit - flush any waiting 217 * clients but don't actually exit until they've gone. 218 */ 219 cmd_wait_for_flush(); 220 if (!TAILQ_EMPTY(&clients)) 221 return (0); 222 223 return (1); 224 } 225 226 /* Exit the server by killing all clients and windows. */ 227 static void 228 server_send_exit(void) 229 { 230 struct client *c, *c1; 231 struct session *s, *s1; 232 233 cmd_wait_for_flush(); 234 235 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 236 if (c->flags & CLIENT_SUSPENDED) 237 server_client_lost(c); 238 else 239 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 240 c->session = NULL; 241 } 242 243 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 244 session_destroy(s); 245 } 246 247 /* Update socket execute permissions based on whether sessions are attached. */ 248 void 249 server_update_socket(void) 250 { 251 struct session *s; 252 static int last = -1; 253 int n, mode; 254 struct stat sb; 255 256 n = 0; 257 RB_FOREACH(s, sessions, &sessions) { 258 if (!(s->flags & SESSION_UNATTACHED)) { 259 n++; 260 break; 261 } 262 } 263 264 if (n != last) { 265 last = n; 266 267 if (stat(socket_path, &sb) != 0) 268 return; 269 mode = sb.st_mode & ACCESSPERMS; 270 if (n != 0) { 271 if (mode & S_IRUSR) 272 mode |= S_IXUSR; 273 if (mode & S_IRGRP) 274 mode |= S_IXGRP; 275 if (mode & S_IROTH) 276 mode |= S_IXOTH; 277 } else 278 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 279 chmod(socket_path, mode); 280 } 281 } 282 283 /* Callback for server socket. */ 284 static void 285 server_accept(int fd, short events, __unused void *data) 286 { 287 struct sockaddr_storage sa; 288 socklen_t slen = sizeof sa; 289 int newfd; 290 291 server_add_accept(0); 292 if (!(events & EV_READ)) 293 return; 294 295 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 296 if (newfd == -1) { 297 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 298 return; 299 if (errno == ENFILE || errno == EMFILE) { 300 /* Delete and don't try again for 1 second. */ 301 server_add_accept(1); 302 return; 303 } 304 fatal("accept failed"); 305 } 306 if (server_exit) { 307 close(newfd); 308 return; 309 } 310 server_client_create(newfd); 311 } 312 313 /* 314 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 315 * event - used to backoff when running out of file descriptors. 316 */ 317 void 318 server_add_accept(int timeout) 319 { 320 struct timeval tv = { timeout, 0 }; 321 322 if (event_initialized(&server_ev_accept)) 323 event_del(&server_ev_accept); 324 325 if (timeout == 0) { 326 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 327 NULL); 328 event_add(&server_ev_accept, NULL); 329 } else { 330 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 331 server_accept, NULL); 332 event_add(&server_ev_accept, &tv); 333 } 334 } 335 336 /* Signal handler. */ 337 static void 338 server_signal(int sig) 339 { 340 int fd; 341 342 switch (sig) { 343 case SIGTERM: 344 server_exit = 1; 345 server_send_exit(); 346 break; 347 case SIGCHLD: 348 server_child_signal(); 349 break; 350 case SIGUSR1: 351 event_del(&server_ev_accept); 352 fd = server_create_socket(); 353 if (fd != -1) { 354 close(server_fd); 355 server_fd = fd; 356 server_update_socket(); 357 } 358 server_add_accept(0); 359 break; 360 } 361 } 362 363 /* Handle SIGCHLD. */ 364 static void 365 server_child_signal(void) 366 { 367 int status; 368 pid_t pid; 369 370 for (;;) { 371 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 372 case -1: 373 if (errno == ECHILD) 374 return; 375 fatal("waitpid failed"); 376 case 0: 377 return; 378 } 379 if (WIFSTOPPED(status)) 380 server_child_stopped(pid, status); 381 else if (WIFEXITED(status) || WIFSIGNALED(status)) 382 server_child_exited(pid, status); 383 } 384 } 385 386 /* Handle exited children. */ 387 static void 388 server_child_exited(pid_t pid, int status) 389 { 390 struct window *w, *w1; 391 struct window_pane *wp; 392 struct job *job; 393 394 RB_FOREACH_SAFE(w, windows, &windows, w1) { 395 TAILQ_FOREACH(wp, &w->panes, entry) { 396 if (wp->pid == pid) { 397 wp->status = status; 398 server_destroy_pane(wp, 1); 399 break; 400 } 401 } 402 } 403 404 LIST_FOREACH(job, &all_jobs, lentry) { 405 if (pid == job->pid) { 406 job_died(job, status); /* might free job */ 407 break; 408 } 409 } 410 } 411 412 /* Handle stopped children. */ 413 static void 414 server_child_stopped(pid_t pid, int status) 415 { 416 struct window *w; 417 struct window_pane *wp; 418 419 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 420 return; 421 422 RB_FOREACH(w, windows, &windows) { 423 TAILQ_FOREACH(wp, &w->panes, entry) { 424 if (wp->pid == pid) { 425 if (killpg(pid, SIGCONT) != 0) 426 kill(pid, SIGCONT); 427 } 428 } 429 } 430 } 431