server.c

   1 /* $OpenBSD$ */
   2
   3 /*
   4  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
   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 <syslog.h>
  35 #include <termios.h>
  36 #include <time.h>
  37 #include <unistd.h>
  38
  39 #include "tmux.h"
  40
  41 /*
  42  * Main server functions.
  43  */
  44
  45 /* Client list. */
  46 struct clients   clients;
  47 struct clients   dead_clients;
  48
  49 int              server_fd;
  50 int              server_shutdown;
  51 struct event     server_ev_accept;
  52 struct event     server_ev_second;
  53
  54 int              server_create_socket(void);
  55 void             server_loop(void);
  56 int              server_should_shutdown(void);
  57 void             server_send_shutdown(void);
  58 void             server_clean_dead(void);
  59 void             server_accept_callback(int, short, void *);
  60 void             server_signal_callback(int, short, void *);
  61 void             server_child_signal(void);
  62 void             server_child_exited(pid_t, int);
  63 void             server_child_stopped(pid_t, int);
  64 void             server_second_callback(int, short, void *);
  65 void             server_lock_server(void);
  66 void             server_lock_sessions(void);
  67
  68 /* Create server socket. */
  69 int
  70 server_create_socket(void)
  71 {
  72         struct sockaddr_un      sa;
  73         size_t                  size;
  74         mode_t                  mask;
  75         int                     fd, mode;
  76
  77         memset(&sa, 0, sizeof sa);
  78         sa.sun_family = AF_UNIX;
  79         size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path);
  80         if (size >= sizeof sa.sun_path) {
  81                 errno = ENAMETOOLONG;
  82                 fatal("socket failed");
  83         }
  84         unlink(sa.sun_path);
  85
  86         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
  87                 fatal("socket failed");
  88
  89         mask = umask(S_IXUSR|S_IXGRP|S_IRWXO);
  90         if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
  91                 fatal("bind failed");
  92         umask(mask);
  93
  94         if (listen(fd, 16) == -1)
  95                 fatal("listen failed");
  96
  97         if ((mode = fcntl(fd, F_GETFL)) == -1)
  98                 fatal("fcntl failed");
  99         if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1)
 100                 fatal("fcntl failed");
 101
 102         server_update_socket();
 103
 104         return (fd);
 105 }
 106
 107 /* Fork new server. */
 108 int
 109 server_start(void)
 110 {
 111         struct window_pane      *wp;
 112         int                      pair[2];
 113         char                    *cause;
 114         struct timeval           tv;
 115         u_int                    i;
 116
 117         /* The first client is special and gets a socketpair; create it. */
 118         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 119                 fatal("socketpair failed");
 120
 121         switch (fork()) {
 122         case -1:
 123                 fatal("fork failed");
 124         case 0:
 125                 break;
 126         default:
 127                 close(pair[1]);
 128                 return (pair[0]);
 129         }
 130         close(pair[0]);
 131
 132         /*
 133          * Must daemonise before loading configuration as the PID changes so
 134          * $TMUX would be wrong for sessions created in the config file.
 135          */
 136         if (daemon(1, 0) != 0)
 137                 fatal("daemon failed");
 138
 139         /* event_init() was called in our parent, need to reinit. */
 140         if (event_reinit(ev_base) != 0)
 141                 fatal("event_reinit failed");
 142         clear_signals(0);
 143
 144         logfile("server");
 145         log_debug("server started, pid %ld", (long) getpid());
 146
 147         ARRAY_INIT(&windows);
 148         ARRAY_INIT(&clients);
 149         ARRAY_INIT(&dead_clients);
 150         ARRAY_INIT(&sessions);
 151         ARRAY_INIT(&dead_sessions);
 152         TAILQ_INIT(&session_groups);
 153         mode_key_init_trees();
 154         key_bindings_init();
 155         utf8_build();
 156
 157         start_time = time(NULL);
 158         log_debug("socket path %s", socket_path);
 159         setproctitle("server (%s)", socket_path);
 160
 161         server_fd = server_create_socket();
 162         server_client_create(pair[1]);
 163
 164         if (access(SYSTEM_CFG, R_OK) == 0)
 165                 load_cfg(SYSTEM_CFG, NULL, &cfg_causes);
 166         else if (errno != ENOENT) {
 167                 cfg_add_cause(
 168                     &cfg_causes, "%s: %s", strerror(errno), SYSTEM_CFG);
 169         }
 170         if (cfg_file != NULL)
 171                 load_cfg(cfg_file, NULL, &cfg_causes);
 172
 173         /*
 174          * If there is a session already, put the current window and pane into
 175          * more mode.
 176          */
 177         if (!ARRAY_EMPTY(&sessions) && !ARRAY_EMPTY(&cfg_causes)) {
 178                 wp = ARRAY_FIRST(&sessions)->curw->window->active;
 179                 window_pane_set_mode(wp, &window_copy_mode);
 180                 window_copy_init_for_output(wp);
 181                 for (i = 0; i < ARRAY_LENGTH(&cfg_causes); i++) {
 182                         cause = ARRAY_ITEM(&cfg_causes, i);
 183                         window_copy_add(wp, "%s", cause);
 184                         xfree(cause);
 185                 }
 186                 ARRAY_FREE(&cfg_causes);
 187         }
 188         cfg_finished = 1;
 189
 190         event_set(&server_ev_accept,
 191             server_fd, EV_READ|EV_PERSIST, server_accept_callback, NULL);
 192         event_add(&server_ev_accept, NULL);
 193
 194         memset(&tv, 0, sizeof tv);
 195         tv.tv_sec = 1;
 196         evtimer_set(&server_ev_second, server_second_callback, NULL);
 197         evtimer_add(&server_ev_second, &tv);
 198
 199         set_signals(server_signal_callback);
 200         server_loop();
 201         exit(0);
 202 }
 203
 204 /* Main server loop. */
 205 void
 206 server_loop(void)
 207 {
 208         while (!server_should_shutdown()) {
 209                 event_loop(EVLOOP_ONCE);
 210
 211                 server_window_loop();
 212                 server_client_loop();
 213
 214                 key_bindings_clean();
 215                 server_clean_dead();
 216         }
 217 }
 218
 219 /* Check if the server should be shutting down (no more clients or sessions). */
 220 int
 221 server_should_shutdown(void)
 222 {
 223         u_int   i;
 224
 225         if (!options_get_number(&global_options, "exit-unattached")) {
 226                 for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 227                         if (ARRAY_ITEM(&sessions, i) != NULL)
 228                                 return (0);
 229                 }
 230         }
 231         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 232                 if (ARRAY_ITEM(&clients, i) != NULL)
 233                         return (0);
 234         }
 235         return (1);
 236 }
 237
 238 /* Shutdown the server by killing all clients and windows. */
 239 void
 240 server_send_shutdown(void)
 241 {
 242         struct client   *c;
 243         struct session  *s;
 244         u_int            i;
 245
 246         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 247                 c = ARRAY_ITEM(&clients, i);
 248                 if (c != NULL) {
 249                         if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
 250                                 server_client_lost(c);
 251                         else
 252                                 server_write_client(c, MSG_SHUTDOWN, NULL, 0);
 253                         c->session = NULL;
 254                 }
 255         }
 256
 257         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 258                 if ((s = ARRAY_ITEM(&sessions, i)) != NULL)
 259                         session_destroy(s);
 260         }
 261 }
 262
 263 /* Free dead, unreferenced clients and sessions. */
 264 void
 265 server_clean_dead(void)
 266 {
 267         struct session  *s;
 268         struct client   *c;
 269         u_int            i;
 270
 271         for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
 272                 s = ARRAY_ITEM(&dead_sessions, i);
 273                 if (s == NULL || s->references != 0)
 274                         continue;
 275                 ARRAY_SET(&dead_sessions, i, NULL);
 276                 xfree(s);
 277         }
 278
 279         for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
 280                 c = ARRAY_ITEM(&dead_clients, i);
 281                 if (c == NULL || c->references != 0)
 282                         continue;
 283                 ARRAY_SET(&dead_clients, i, NULL);
 284                 xfree(c);
 285         }
 286 }
 287
 288 /* Update socket execute permissions based on whether sessions are attached. */
 289 void
 290 server_update_socket(void)
 291 {
 292         struct session  *s;
 293         u_int            i;
 294         static int       last = -1;
 295         int              n, mode;
 296         struct stat      sb;
 297
 298         n = 0;
 299         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 300                 s = ARRAY_ITEM(&sessions, i);
 301                 if (s != NULL && !(s->flags & SESSION_UNATTACHED)) {
 302                         n++;
 303                         break;
 304                 }
 305         }
 306
 307         if (n != last) {
 308                 last = n;
 309
 310                 if (stat(socket_path, &sb) != 0)
 311                         return;
 312                 mode = sb.st_mode;
 313                 if (n != 0) {
 314                         if (mode & S_IRUSR)
 315                                 mode |= S_IXUSR;
 316                         if (mode & S_IRGRP)
 317                                 mode |= S_IXGRP;
 318                         if (mode & S_IROTH)
 319                                 mode |= S_IXOTH;
 320                 } else
 321                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 322                 chmod(socket_path, mode);
 323         }
 324 }
 325
 326 /* Callback for server socket. */
 327 /* ARGSUSED */
 328 void
 329 server_accept_callback(int fd, short events, unused void *data)
 330 {
 331         struct sockaddr_storage sa;
 332         socklen_t               slen = sizeof sa;
 333         int                     newfd;
 334
 335         if (!(events & EV_READ))
 336                 return;
 337
 338         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 339         if (newfd == -1) {
 340                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 341                         return;
 342                 fatal("accept failed");
 343         }
 344         if (server_shutdown) {
 345                 close(newfd);
 346                 return;
 347         }
 348         server_client_create(newfd);
 349 }
 350
 351 /* Signal handler. */
 352 /* ARGSUSED */
 353 void
 354 server_signal_callback(int sig, unused short events, unused void *data)
 355 {
 356         switch (sig) {
 357         case SIGTERM:
 358                 server_shutdown = 1;
 359                 server_send_shutdown();
 360                 break;
 361         case SIGCHLD:
 362                 server_child_signal();
 363                 break;
 364         case SIGUSR1:
 365                 event_del(&server_ev_accept);
 366                 close(server_fd);
 367                 server_fd = server_create_socket();
 368                 event_set(&server_ev_accept, server_fd,
 369                     EV_READ|EV_PERSIST, server_accept_callback, NULL);
 370                 event_add(&server_ev_accept, NULL);
 371                 break;
 372         }
 373 }
 374
 375 /* Handle SIGCHLD. */
 376 void
 377 server_child_signal(void)
 378 {
 379         int      status;
 380         pid_t    pid;
 381
 382         for (;;) {
 383                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 384                 case -1:
 385                         if (errno == ECHILD)
 386                                 return;
 387                         fatal("waitpid failed");
 388                 case 0:
 389                         return;
 390                 }
 391                 if (WIFSTOPPED(status))
 392                         server_child_stopped(pid, status);
 393                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 394                         server_child_exited(pid, status);
 395         }
 396 }
 397
 398 /* Handle exited children. */
 399 void
 400 server_child_exited(pid_t pid, int status)
 401 {
 402         struct window           *w;
 403         struct window_pane      *wp;
 404         struct job              *job;
 405         u_int                    i;
 406
 407         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 408                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 409                         continue;
 410                 TAILQ_FOREACH(wp, &w->panes, entry) {
 411                         if (wp->pid == pid) {
 412                                 server_destroy_pane(wp);
 413                                 break;
 414                         }
 415                 }
 416         }
 417
 418         SLIST_FOREACH(job, &all_jobs, lentry) {
 419                 if (pid == job->pid) {
 420                         job_died(job, status);  /* might free job */
 421                         break;
 422                 }
 423         }
 424 }
 425
 426 /* Handle stopped children. */
 427 void
 428 server_child_stopped(pid_t pid, int status)
 429 {
 430         struct window           *w;
 431         struct window_pane      *wp;
 432         u_int                    i;
 433
 434         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 435                 return;
 436
 437         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 438                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 439                         continue;
 440                 TAILQ_FOREACH(wp, &w->panes, entry) {
 441                         if (wp->pid == pid) {
 442                                 if (killpg(pid, SIGCONT) != 0)
 443                                         kill(pid, SIGCONT);
 444                         }
 445                 }
 446         }
 447 }
 448
 449 /* Handle once-per-second timer events. */
 450 /* ARGSUSED */
 451 void
 452 server_second_callback(unused int fd, unused short events, unused void *arg)
 453 {
 454         struct window           *w;
 455         struct window_pane      *wp;
 456         struct timeval           tv;
 457         u_int                    i;
 458
 459         if (options_get_number(&global_s_options, "lock-server"))
 460                 server_lock_server();
 461         else
 462                 server_lock_sessions();
 463
 464         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 465                 w = ARRAY_ITEM(&windows, i);
 466                 if (w == NULL)
 467                         continue;
 468
 469                 TAILQ_FOREACH(wp, &w->panes, entry) {
 470                         if (wp->mode != NULL && wp->mode->timer != NULL)
 471                                 wp->mode->timer(wp);
 472                 }
 473         }
 474
 475         server_client_status_timer();
 476
 477         evtimer_del(&server_ev_second);
 478         memset(&tv, 0, sizeof tv);
 479         tv.tv_sec = 1;
 480         evtimer_add(&server_ev_second, &tv);
 481 }
 482
 483 /* Lock the server if ALL sessions have hit the time limit. */
 484 void
 485 server_lock_server(void)
 486 {
 487         struct session  *s;
 488         u_int            i;
 489         int              timeout;
 490         time_t           t;
 491
 492         t = time(NULL);
 493         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 494                 if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
 495                         continue;
 496
 497                 if (s->flags & SESSION_UNATTACHED) {
 498                         if (gettimeofday(&s->activity_time, NULL) != 0)
 499                                 fatal("gettimeofday failed");
 500                         continue;
 501                 }
 502
 503                 timeout = options_get_number(&s->options, "lock-after-time");
 504                 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
 505                         return; /* not timed out */
 506         }
 507
 508         server_lock();
 509         recalculate_sizes();
 510 }
 511
 512 /* Lock any sessions which have timed out. */
 513 void
 514 server_lock_sessions(void)
 515 {
 516         struct session  *s;
 517         u_int            i;
 518         int              timeout;
 519         time_t           t;
 520
 521         t = time(NULL);
 522         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 523                 if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
 524                         continue;
 525
 526                 if (s->flags & SESSION_UNATTACHED) {
 527                         if (gettimeofday(&s->activity_time, NULL) != 0)
 528                                 fatal("gettimeofday failed");
 529                         continue;
 530                 }
 531
 532                 timeout = options_get_number(&s->options, "lock-after-time");
 533                 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 534                         server_lock_session(s);
 535                         recalculate_sizes();
 536                 }
 537         }
 538 }