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