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;
  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         setblocking(fd, 0);
  99
 100         server_update_socket();
 101
 102         return (fd);
 103 }
 104
 105 /* Fork new server. */
 106 int
 107 server_start(void)
 108 {
 109         struct window_pane      *wp;
 110         int                      pair[2];
 111         char                    *cause;
 112         struct timeval           tv;
 113         u_int                    i;
 114
 115         /* The first client is special and gets a socketpair; create it. */
 116         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 117                 fatal("socketpair failed");
 118
 119         switch (fork()) {
 120         case -1:
 121                 fatal("fork failed");
 122         case 0:
 123                 break;
 124         default:
 125                 close(pair[1]);
 126                 return (pair[0]);
 127         }
 128         close(pair[0]);
 129
 130         /*
 131          * Must daemonise before loading configuration as the PID changes so
 132          * $TMUX would be wrong for sessions created in the config file.
 133          */
 134         if (daemon(1, 0) != 0)
 135                 fatal("daemon failed");
 136
 137         /* event_init() was called in our parent, need to reinit. */
 138         if (event_reinit(ev_base) != 0)
 139                 fatal("event_reinit failed");
 140         clear_signals(0);
 141
 142         logfile("server");
 143         log_debug("server started, pid %ld", (long) getpid());
 144
 145         ARRAY_INIT(&windows);
 146         ARRAY_INIT(&clients);
 147         ARRAY_INIT(&dead_clients);
 148         RB_INIT(&sessions);
 149         RB_INIT(&dead_sessions);
 150         TAILQ_INIT(&session_groups);
 151         ARRAY_INIT(&global_buffers);
 152         mode_key_init_trees();
 153         key_bindings_init();
 154         utf8_build();
 155
 156         start_time = time(NULL);
 157         log_debug("socket path %s", socket_path);
 158         setproctitle("server (%s)", socket_path);
 159
 160         server_fd = server_create_socket();
 161         server_client_create(pair[1]);
 162
 163         if (access(SYSTEM_CFG, R_OK) == 0)
 164                 load_cfg(SYSTEM_CFG, NULL, &cfg_causes);
 165         else if (errno != ENOENT) {
 166                 cfg_add_cause(
 167                     &cfg_causes, "%s: %s", strerror(errno), SYSTEM_CFG);
 168         }
 169         if (cfg_file != NULL)
 170                 load_cfg(cfg_file, NULL, &cfg_causes);
 171
 172         /*
 173          * If there is a session already, put the current window and pane into
 174          * more mode.
 175          */
 176         if (!RB_EMPTY(&sessions) && !ARRAY_EMPTY(&cfg_causes)) {
 177                 wp = RB_MIN(sessions, &sessions)->curw->window->active;
 178                 window_pane_set_mode(wp, &window_copy_mode);
 179                 window_copy_init_for_output(wp);
 180                 for (i = 0; i < ARRAY_LENGTH(&cfg_causes); i++) {
 181                         cause = ARRAY_ITEM(&cfg_causes, i);
 182                         window_copy_add(wp, "%s", cause);
 183                         xfree(cause);
 184                 }
 185                 ARRAY_FREE(&cfg_causes);
 186         }
 187         cfg_finished = 1;
 188
 189         event_set(&server_ev_accept,
 190             server_fd, EV_READ|EV_PERSIST, server_accept_callback, NULL);
 191         event_add(&server_ev_accept, NULL);
 192
 193         memset(&tv, 0, sizeof tv);
 194         tv.tv_sec = 1;
 195         evtimer_set(&server_ev_second, server_second_callback, NULL);
 196         evtimer_add(&server_ev_second, &tv);
 197
 198         set_signals(server_signal_callback);
 199         server_loop();
 200         exit(0);
 201 }
 202
 203 /* Main server loop. */
 204 void
 205 server_loop(void)
 206 {
 207         while (!server_should_shutdown()) {
 208                 event_loop(EVLOOP_ONCE);
 209
 210                 server_window_loop();
 211                 server_client_loop();
 212
 213                 key_bindings_clean();
 214                 server_clean_dead();
 215         }
 216 }
 217
 218 /* Check if the server should be shutting down (no more clients or sessions). */
 219 int
 220 server_should_shutdown(void)
 221 {
 222         u_int   i;
 223
 224         if (!options_get_number(&global_options, "exit-unattached")) {
 225                 if (!RB_EMPTY(&sessions))
 226                         return (0);
 227         }
 228         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 229                 if (ARRAY_ITEM(&clients, i) != NULL)
 230                         return (0);
 231         }
 232         return (1);
 233 }
 234
 235 /* Shutdown the server by killing all clients and windows. */
 236 void
 237 server_send_shutdown(void)
 238 {
 239         struct client   *c;
 240         struct session  *s, *next_s;
 241         u_int            i;
 242
 243         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 244                 c = ARRAY_ITEM(&clients, i);
 245                 if (c != NULL) {
 246                         if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
 247                                 server_client_lost(c);
 248                         else
 249                                 server_write_client(c, MSG_SHUTDOWN, NULL, 0);
 250                         c->session = NULL;
 251                 }
 252         }
 253
 254         s = RB_MIN(sessions, &sessions);
 255         while (s != NULL) {
 256                 next_s = RB_NEXT(sessions, &sessions, s);
 257                 session_destroy(s);
 258                 s = next_s;
 259         }
 260 }
 261
 262 /* Free dead, unreferenced clients and sessions. */
 263 void
 264 server_clean_dead(void)
 265 {
 266         struct session  *s, *next_s;
 267         struct client   *c;
 268         u_int            i;
 269
 270         s = RB_MIN(sessions, &dead_sessions);
 271         while (s != NULL) {
 272                 next_s = RB_NEXT(sessions, &dead_sessions, s);
 273                 if (s->references == 0) {
 274                         RB_REMOVE(sessions, &dead_sessions, s);
 275                         xfree(s->name);
 276                         xfree(s);
 277                 }
 278                 s = next_s;
 279         }
 280
 281         for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
 282                 c = ARRAY_ITEM(&dead_clients, i);
 283                 if (c == NULL || c->references != 0)
 284                         continue;
 285                 ARRAY_SET(&dead_clients, i, NULL);
 286                 xfree(c);
 287         }
 288 }
 289
 290 /* Update socket execute permissions based on whether sessions are attached. */
 291 void
 292 server_update_socket(void)
 293 {
 294         struct session  *s;
 295         static int       last = -1;
 296         int              n, mode;
 297         struct stat      sb;
 298
 299         n = 0;
 300         RB_FOREACH(s, sessions, &sessions) {
 301                 if (!(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         LIST_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         int              timeout;
 489         time_t           t;
 490
 491         t = time(NULL);
 492         RB_FOREACH(s, sessions, &sessions) {
 493                 if (s->flags & SESSION_UNATTACHED)
 494                         continue;
 495                 timeout = options_get_number(&s->options, "lock-after-time");
 496                 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
 497                         return; /* not timed out */
 498         }
 499
 500         server_lock();
 501         recalculate_sizes();
 502 }
 503
 504 /* Lock any sessions which have timed out. */
 505 void
 506 server_lock_sessions(void)
 507 {
 508         struct session  *s;
 509         int              timeout;
 510         time_t           t;
 511
 512         t = time(NULL);
 513         RB_FOREACH(s, sessions, &sessions) {
 514                 if (s->flags & SESSION_UNATTACHED)
 515                         continue;
 516                 timeout = options_get_number(&s->options, "lock-after-time");
 517                 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 518                         server_lock_session(s);
 519                         recalculate_sizes();
 520                 }
 521         }
 522 }