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