1 /* $OpenBSD: server.c,v 1.171 2017/06/04 08:25:57 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 event_base *base, int lockfd, char *lockfile) 140 { 141 int pair[2]; 142 struct job *job; 143 144 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 145 fatal("socketpair failed"); 146 147 server_proc = proc_start("server", base, 1, server_signal); 148 if (server_proc == NULL) { 149 close(pair[1]); 150 return (pair[0]); 151 } 152 close(pair[0]); 153 154 if (log_get_level() > 1) 155 tty_create_log(); 156 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 157 "tty ps", NULL) != 0) 158 fatal("pledge failed"); 159 160 RB_INIT(&windows); 161 RB_INIT(&all_window_panes); 162 TAILQ_INIT(&clients); 163 RB_INIT(&sessions); 164 RB_INIT(&session_groups); 165 key_bindings_init(); 166 167 gettimeofday(&start_time, NULL); 168 169 server_fd = server_create_socket(); 170 if (server_fd == -1) 171 fatal("couldn't create socket"); 172 server_update_socket(); 173 server_client_create(pair[1]); 174 175 if (lockfd >= 0) { 176 unlink(lockfile); 177 free(lockfile); 178 close(lockfd); 179 } 180 181 start_cfg(); 182 183 server_add_accept(0); 184 185 proc_loop(server_proc, server_loop); 186 187 LIST_FOREACH(job, &all_jobs, entry) { 188 if (job->pid != -1) 189 kill(job->pid, SIGTERM); 190 } 191 192 status_prompt_save_history(); 193 exit(0); 194 } 195 196 /* Server loop callback. */ 197 static int 198 server_loop(void) 199 { 200 struct client *c; 201 u_int items; 202 203 do { 204 items = cmdq_next(NULL); 205 TAILQ_FOREACH(c, &clients, entry) { 206 if (c->flags & CLIENT_IDENTIFIED) 207 items += cmdq_next(c); 208 } 209 } while (items != 0); 210 211 server_client_loop(); 212 213 if (!options_get_number(global_options, "exit-unattached")) { 214 if (!RB_EMPTY(&sessions)) 215 return (0); 216 } 217 218 TAILQ_FOREACH(c, &clients, entry) { 219 if (c->session != NULL) 220 return (0); 221 } 222 223 /* 224 * No attached clients therefore want to exit - flush any waiting 225 * clients but don't actually exit until they've gone. 226 */ 227 cmd_wait_for_flush(); 228 if (!TAILQ_EMPTY(&clients)) 229 return (0); 230 231 return (1); 232 } 233 234 /* Exit the server by killing all clients and windows. */ 235 static void 236 server_send_exit(void) 237 { 238 struct client *c, *c1; 239 struct session *s, *s1; 240 241 cmd_wait_for_flush(); 242 243 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 244 if (c->flags & CLIENT_SUSPENDED) 245 server_client_lost(c); 246 else 247 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 248 c->session = NULL; 249 } 250 251 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 252 session_destroy(s); 253 } 254 255 /* Update socket execute permissions based on whether sessions are attached. */ 256 void 257 server_update_socket(void) 258 { 259 struct session *s; 260 static int last = -1; 261 int n, mode; 262 struct stat sb; 263 264 n = 0; 265 RB_FOREACH(s, sessions, &sessions) { 266 if (!(s->flags & SESSION_UNATTACHED)) { 267 n++; 268 break; 269 } 270 } 271 272 if (n != last) { 273 last = n; 274 275 if (stat(socket_path, &sb) != 0) 276 return; 277 mode = sb.st_mode & ACCESSPERMS; 278 if (n != 0) { 279 if (mode & S_IRUSR) 280 mode |= S_IXUSR; 281 if (mode & S_IRGRP) 282 mode |= S_IXGRP; 283 if (mode & S_IROTH) 284 mode |= S_IXOTH; 285 } else 286 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 287 chmod(socket_path, mode); 288 } 289 } 290 291 /* Callback for server socket. */ 292 static void 293 server_accept(int fd, short events, __unused void *data) 294 { 295 struct sockaddr_storage sa; 296 socklen_t slen = sizeof sa; 297 int newfd; 298 299 server_add_accept(0); 300 if (!(events & EV_READ)) 301 return; 302 303 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 304 if (newfd == -1) { 305 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 306 return; 307 if (errno == ENFILE || errno == EMFILE) { 308 /* Delete and don't try again for 1 second. */ 309 server_add_accept(1); 310 return; 311 } 312 fatal("accept failed"); 313 } 314 if (server_exit) { 315 close(newfd); 316 return; 317 } 318 server_client_create(newfd); 319 } 320 321 /* 322 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 323 * event - used to backoff when running out of file descriptors. 324 */ 325 void 326 server_add_accept(int timeout) 327 { 328 struct timeval tv = { timeout, 0 }; 329 330 if (event_initialized(&server_ev_accept)) 331 event_del(&server_ev_accept); 332 333 if (timeout == 0) { 334 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 335 NULL); 336 event_add(&server_ev_accept, NULL); 337 } else { 338 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 339 server_accept, NULL); 340 event_add(&server_ev_accept, &tv); 341 } 342 } 343 344 /* Signal handler. */ 345 static void 346 server_signal(int sig) 347 { 348 int fd; 349 350 switch (sig) { 351 case SIGTERM: 352 server_exit = 1; 353 server_send_exit(); 354 break; 355 case SIGCHLD: 356 server_child_signal(); 357 break; 358 case SIGUSR1: 359 event_del(&server_ev_accept); 360 fd = server_create_socket(); 361 if (fd != -1) { 362 close(server_fd); 363 server_fd = fd; 364 server_update_socket(); 365 } 366 server_add_accept(0); 367 break; 368 case SIGUSR2: 369 proc_toggle_log(server_proc); 370 break; 371 } 372 } 373 374 /* Handle SIGCHLD. */ 375 static void 376 server_child_signal(void) 377 { 378 int status; 379 pid_t pid; 380 381 for (;;) { 382 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 383 case -1: 384 if (errno == ECHILD) 385 return; 386 fatal("waitpid failed"); 387 case 0: 388 return; 389 } 390 if (WIFSTOPPED(status)) 391 server_child_stopped(pid, status); 392 else if (WIFEXITED(status) || WIFSIGNALED(status)) 393 server_child_exited(pid, status); 394 } 395 } 396 397 /* Handle exited children. */ 398 static void 399 server_child_exited(pid_t pid, int status) 400 { 401 struct window *w, *w1; 402 struct window_pane *wp; 403 struct job *job; 404 405 RB_FOREACH_SAFE(w, windows, &windows, w1) { 406 TAILQ_FOREACH(wp, &w->panes, entry) { 407 if (wp->pid == pid) { 408 wp->status = status; 409 server_destroy_pane(wp, 1); 410 break; 411 } 412 } 413 } 414 415 LIST_FOREACH(job, &all_jobs, entry) { 416 if (pid == job->pid) { 417 job_died(job, status); /* might free job */ 418 break; 419 } 420 } 421 } 422 423 /* Handle stopped children. */ 424 static void 425 server_child_stopped(pid_t pid, int status) 426 { 427 struct window *w; 428 struct window_pane *wp; 429 430 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 431 return; 432 433 RB_FOREACH(w, windows, &windows) { 434 TAILQ_FOREACH(wp, &w->panes, entry) { 435 if (wp->pid == pid) { 436 if (killpg(pid, SIGCONT) != 0) 437 kill(pid, SIGCONT); 438 } 439 } 440 } 441 } 442