1 /* $OpenBSD: server.c,v 1.159 2016/07/07 09:24:09 semarie 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 int server_fd; 48 int server_exit; 49 struct event server_ev_accept; 50 51 struct cmd_find_state marked_pane; 52 53 int server_create_socket(void); 54 int server_loop(void); 55 int server_should_exit(void); 56 void server_send_exit(void); 57 void server_accept(int, short, void *); 58 void server_signal(int); 59 void server_child_signal(void); 60 void server_child_exited(pid_t, int); 61 void server_child_stopped(pid_t, int); 62 63 /* Set marked pane. */ 64 void 65 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 66 { 67 cmd_find_clear_state(&marked_pane, NULL, 0); 68 marked_pane.s = s; 69 marked_pane.wl = wl; 70 marked_pane.w = wl->window; 71 marked_pane.wp = wp; 72 } 73 74 /* Clear marked pane. */ 75 void 76 server_clear_marked(void) 77 { 78 cmd_find_clear_state(&marked_pane, NULL, 0); 79 } 80 81 /* Is this the marked pane? */ 82 int 83 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp) 84 { 85 if (s == NULL || wl == NULL || wp == NULL) 86 return (0); 87 if (marked_pane.s != s || marked_pane.wl != wl) 88 return (0); 89 if (marked_pane.wp != wp) 90 return (0); 91 return (server_check_marked()); 92 } 93 94 /* Check if the marked pane is still valid. */ 95 int 96 server_check_marked(void) 97 { 98 return (cmd_find_valid_state(&marked_pane)); 99 } 100 101 /* Create server socket. */ 102 int 103 server_create_socket(void) 104 { 105 struct sockaddr_un sa; 106 size_t size; 107 mode_t mask; 108 int fd; 109 110 memset(&sa, 0, sizeof sa); 111 sa.sun_family = AF_UNIX; 112 size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path); 113 if (size >= sizeof sa.sun_path) { 114 errno = ENAMETOOLONG; 115 return (-1); 116 } 117 unlink(sa.sun_path); 118 119 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 120 return (-1); 121 122 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO); 123 if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) == -1) 124 return (-1); 125 umask(mask); 126 127 if (listen(fd, 128) == -1) 128 return (-1); 129 setblocking(fd, 0); 130 131 return (fd); 132 } 133 134 /* Fork new server. */ 135 int 136 server_start(struct event_base *base, int lockfd, char *lockfile) 137 { 138 int pair[2]; 139 140 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 141 fatal("socketpair failed"); 142 143 server_proc = proc_start("server", base, 1, server_signal); 144 if (server_proc == NULL) { 145 close(pair[1]); 146 return (pair[0]); 147 } 148 close(pair[0]); 149 150 if (log_get_level() > 3) 151 tty_create_log(); 152 if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec " 153 "tty ps", NULL) != 0) 154 fatal("pledge failed"); 155 156 RB_INIT(&windows); 157 RB_INIT(&all_window_panes); 158 TAILQ_INIT(&clients); 159 RB_INIT(&sessions); 160 TAILQ_INIT(&session_groups); 161 mode_key_init_trees(); 162 key_bindings_init(); 163 164 gettimeofday(&start_time, NULL); 165 166 server_fd = server_create_socket(); 167 if (server_fd == -1) 168 fatal("couldn't create socket"); 169 server_update_socket(); 170 server_client_create(pair[1]); 171 172 if (lockfd >= 0) { 173 unlink(lockfile); 174 free(lockfile); 175 close(lockfd); 176 } 177 178 start_cfg(); 179 180 status_prompt_load_history(); 181 182 server_add_accept(0); 183 184 proc_loop(server_proc, server_loop); 185 status_prompt_save_history(); 186 exit(0); 187 } 188 189 /* Server loop callback. */ 190 int 191 server_loop(void) 192 { 193 struct client *c; 194 195 server_client_loop(); 196 197 if (!options_get_number(global_options, "exit-unattached")) { 198 if (!RB_EMPTY(&sessions)) 199 return (0); 200 } 201 202 TAILQ_FOREACH(c, &clients, entry) { 203 if (c->session != NULL) 204 return (0); 205 } 206 207 /* 208 * No attached clients therefore want to exit - flush any waiting 209 * clients but don't actually exit until they've gone. 210 */ 211 cmd_wait_for_flush(); 212 if (!TAILQ_EMPTY(&clients)) 213 return (0); 214 215 return (1); 216 } 217 218 /* Exit the server by killing all clients and windows. */ 219 void 220 server_send_exit(void) 221 { 222 struct client *c, *c1; 223 struct session *s, *s1; 224 225 cmd_wait_for_flush(); 226 227 TAILQ_FOREACH_SAFE(c, &clients, entry, c1) { 228 if (c->flags & CLIENT_SUSPENDED) 229 server_client_lost(c); 230 else 231 proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0); 232 c->session = NULL; 233 } 234 235 RB_FOREACH_SAFE(s, sessions, &sessions, s1) 236 session_destroy(s); 237 } 238 239 /* Update socket execute permissions based on whether sessions are attached. */ 240 void 241 server_update_socket(void) 242 { 243 struct session *s; 244 static int last = -1; 245 int n, mode; 246 struct stat sb; 247 248 n = 0; 249 RB_FOREACH(s, sessions, &sessions) { 250 if (!(s->flags & SESSION_UNATTACHED)) { 251 n++; 252 break; 253 } 254 } 255 256 if (n != last) { 257 last = n; 258 259 if (stat(socket_path, &sb) != 0) 260 return; 261 mode = sb.st_mode & ACCESSPERMS; 262 if (n != 0) { 263 if (mode & S_IRUSR) 264 mode |= S_IXUSR; 265 if (mode & S_IRGRP) 266 mode |= S_IXGRP; 267 if (mode & S_IROTH) 268 mode |= S_IXOTH; 269 } else 270 mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH); 271 chmod(socket_path, mode); 272 } 273 } 274 275 /* Callback for server socket. */ 276 void 277 server_accept(int fd, short events, __unused void *data) 278 { 279 struct sockaddr_storage sa; 280 socklen_t slen = sizeof sa; 281 int newfd; 282 283 server_add_accept(0); 284 if (!(events & EV_READ)) 285 return; 286 287 newfd = accept(fd, (struct sockaddr *) &sa, &slen); 288 if (newfd == -1) { 289 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED) 290 return; 291 if (errno == ENFILE || errno == EMFILE) { 292 /* Delete and don't try again for 1 second. */ 293 server_add_accept(1); 294 return; 295 } 296 fatal("accept failed"); 297 } 298 if (server_exit) { 299 close(newfd); 300 return; 301 } 302 server_client_create(newfd); 303 } 304 305 /* 306 * Add accept event. If timeout is nonzero, add as a timeout instead of a read 307 * event - used to backoff when running out of file descriptors. 308 */ 309 void 310 server_add_accept(int timeout) 311 { 312 struct timeval tv = { timeout, 0 }; 313 314 if (event_initialized(&server_ev_accept)) 315 event_del(&server_ev_accept); 316 317 if (timeout == 0) { 318 event_set(&server_ev_accept, server_fd, EV_READ, server_accept, 319 NULL); 320 event_add(&server_ev_accept, NULL); 321 } else { 322 event_set(&server_ev_accept, server_fd, EV_TIMEOUT, 323 server_accept, NULL); 324 event_add(&server_ev_accept, &tv); 325 } 326 } 327 328 /* Signal handler. */ 329 void 330 server_signal(int sig) 331 { 332 int fd; 333 334 switch (sig) { 335 case SIGTERM: 336 server_exit = 1; 337 server_send_exit(); 338 break; 339 case SIGCHLD: 340 server_child_signal(); 341 break; 342 case SIGUSR1: 343 event_del(&server_ev_accept); 344 fd = server_create_socket(); 345 if (fd != -1) { 346 close(server_fd); 347 server_fd = fd; 348 server_update_socket(); 349 } 350 server_add_accept(0); 351 break; 352 } 353 } 354 355 /* Handle SIGCHLD. */ 356 void 357 server_child_signal(void) 358 { 359 int status; 360 pid_t pid; 361 362 for (;;) { 363 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) { 364 case -1: 365 if (errno == ECHILD) 366 return; 367 fatal("waitpid failed"); 368 case 0: 369 return; 370 } 371 if (WIFSTOPPED(status)) 372 server_child_stopped(pid, status); 373 else if (WIFEXITED(status) || WIFSIGNALED(status)) 374 server_child_exited(pid, status); 375 } 376 } 377 378 /* Handle exited children. */ 379 void 380 server_child_exited(pid_t pid, int status) 381 { 382 struct window *w, *w1; 383 struct window_pane *wp; 384 struct job *job; 385 386 RB_FOREACH_SAFE(w, windows, &windows, w1) { 387 TAILQ_FOREACH(wp, &w->panes, entry) { 388 if (wp->pid == pid) { 389 wp->status = status; 390 server_destroy_pane(wp, 1); 391 break; 392 } 393 } 394 } 395 396 LIST_FOREACH(job, &all_jobs, lentry) { 397 if (pid == job->pid) { 398 job_died(job, status); /* might free job */ 399 break; 400 } 401 } 402 } 403 404 /* Handle stopped children. */ 405 void 406 server_child_stopped(pid_t pid, int status) 407 { 408 struct window *w; 409 struct window_pane *wp; 410 411 if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU) 412 return; 413 414 RB_FOREACH(w, windows, &windows) { 415 TAILQ_FOREACH(wp, &w->panes, entry) { 416 if (wp->pid == pid) { 417 if (killpg(pid, SIGCONT) != 0) 418 kill(pid, SIGCONT); 419 } 420 } 421 } 422 } 423