1 /* $OpenBSD: server.c,v 1.166 2017/02/09 15:04:53 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 RB_INIT(&session_groups); 160 key_bindings_init(); 161 162 gettimeofday(&start_time, NULL); 163 164 server_fd = server_create_socket(); 165 if (server_fd == -1) 166 fatal("couldn't create socket"); 167 server_update_socket(); 168 server_client_create(pair[1]); 169 170 if (lockfd >= 0) { 171 unlink(lockfile); 172 free(lockfile); 173 close(lockfd); 174 } 175 176 start_cfg(); 177 178 status_prompt_load_history(); 179 180 server_add_accept(0); 181 182 proc_loop(server_proc, server_loop); 183 status_prompt_save_history(); 184 exit(0); 185 } 186 187 /* Server loop callback. */ 188 static int 189 server_loop(void) 190 { 191 struct client *c; 192 u_int items; 193 194 do { 195 items = cmdq_next(NULL); 196 TAILQ_FOREACH(c, &clients, entry) { 197 if (c->flags & CLIENT_IDENTIFIED) 198 items += cmdq_next(c); 199 } 200 } while (items != 0); 201 202 server_client_loop(); 203 204 if (!options_get_number(global_options, "exit-unattached")) { 205 if (!RB_EMPTY(&sessions)) 206 return (0); 207 } 208 209 TAILQ_FOREACH(c, &clients, entry) { 210 if (c->session != NULL) 211 return (0); 212 } 213 214 /* 215 * No attached clients therefore want to exit - flush any waiting 216 * clients but don't actually exit until they've gone. 217 */ 218 cmd_wait_for_flush(); 219 if (!TAILQ_EMPTY(&clients)) 220 return (0); 221 222 return (1); 223 } 224 225 /* Exit the server by killing all clients and windows. */ 226 static void 227 server_send_exit(void) 228 { 229 struct client *c, *c1; 230 struct session *s, *s1; 231 232 cmd_wait_for_flush(); 233 234 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 235 if (c->flags & CLIENT_SUSPENDED) 236 server_client_lost(c); 237 else 238 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 239 c->session = NULL; 240 } 241 242 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 243 session_destroy(s); 244 } 245 246 /* Update socket execute permissions based on whether sessions are attached. */ 247 void 248 server_update_socket(void) 249 { 250 struct session *s; 251 static int last = -1; 252 int n, mode; 253 struct stat sb; 254 255 n = 0; 256 RB_FOREACH(s, sessions, &sessions) { 257 if (!(s->flags & SESSION_UNATTACHED)) { 258 n++; 259 break; 260 } 261 } 262 263 if (n != last) { 264 last = n; 265 266 if (stat(socket_path, &sb) != 0) 267 return; 268 mode = sb.st_mode & ACCESSPERMS; 269 if (n != 0) { 270 if (mode & S_IRUSR) 271 mode |= S_IXUSR; 272 if (mode & S_IRGRP) 273 mode |= S_IXGRP; 274 if (mode & S_IROTH) 275 mode |= S_IXOTH; 276 } else 277 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 278 chmod(socket_path, mode); 279 } 280 } 281 282 /* Callback for server socket. */ 283 static void 284 server_accept(int fd, short events, __unused void *data) 285 { 286 struct sockaddr_storage sa; 287 socklen_t slen = sizeof sa; 288 int newfd; 289 290 server_add_accept(0); 291 if (!(events & EV_READ)) 292 return; 293 294 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 295 if (newfd == -1) { 296 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 297 return; 298 if (errno == ENFILE || errno == EMFILE) { 299 /* Delete and don't try again for 1 second. */ 300 server_add_accept(1); 301 return; 302 } 303 fatal("accept failed"); 304 } 305 if (server_exit) { 306 close(newfd); 307 return; 308 } 309 server_client_create(newfd); 310 } 311 312 /* 313 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 314 * event - used to backoff when running out of file descriptors. 315 */ 316 void 317 server_add_accept(int timeout) 318 { 319 struct timeval tv = { timeout, 0 }; 320 321 if (event_initialized(&server_ev_accept)) 322 event_del(&server_ev_accept); 323 324 if (timeout == 0) { 325 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 326 NULL); 327 event_add(&server_ev_accept, NULL); 328 } else { 329 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 330 server_accept, NULL); 331 event_add(&server_ev_accept, &tv); 332 } 333 } 334 335 /* Signal handler. */ 336 static void 337 server_signal(int sig) 338 { 339 int fd; 340 341 switch (sig) { 342 case SIGTERM: 343 server_exit = 1; 344 server_send_exit(); 345 break; 346 case SIGCHLD: 347 server_child_signal(); 348 break; 349 case SIGUSR1: 350 event_del(&server_ev_accept); 351 fd = server_create_socket(); 352 if (fd != -1) { 353 close(server_fd); 354 server_fd = fd; 355 server_update_socket(); 356 } 357 server_add_accept(0); 358 break; 359 } 360 } 361 362 /* Handle SIGCHLD. */ 363 static void 364 server_child_signal(void) 365 { 366 int status; 367 pid_t pid; 368 369 for (;;) { 370 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 371 case -1: 372 if (errno == ECHILD) 373 return; 374 fatal("waitpid failed"); 375 case 0: 376 return; 377 } 378 if (WIFSTOPPED(status)) 379 server_child_stopped(pid, status); 380 else if (WIFEXITED(status) || WIFSIGNALED(status)) 381 server_child_exited(pid, status); 382 } 383 } 384 385 /* Handle exited children. */ 386 static void 387 server_child_exited(pid_t pid, int status) 388 { 389 struct window *w, *w1; 390 struct window_pane *wp; 391 struct job *job; 392 393 RB_FOREACH_SAFE(w, windows, &windows, w1) { 394 TAILQ_FOREACH(wp, &w->panes, entry) { 395 if (wp->pid == pid) { 396 wp->status = status; 397 server_destroy_pane(wp, 1); 398 break; 399 } 400 } 401 } 402 403 LIST_FOREACH(job, &all_jobs, lentry) { 404 if (pid == job->pid) { 405 job_died(job, status); /* might free job */ 406 break; 407 } 408 } 409 } 410 411 /* Handle stopped children. */ 412 static void 413 server_child_stopped(pid_t pid, int status) 414 { 415 struct window *w; 416 struct window_pane *wp; 417 418 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 419 return; 420 421 RB_FOREACH(w, windows, &windows) { 422 TAILQ_FOREACH(wp, &w->panes, entry) { 423 if (wp->pid == pid) { 424 if (killpg(pid, SIGCONT) != 0) 425 kill(pid, SIGCONT); 426 } 427 } 428 } 429 } 430