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(int lockfd, char *lockfile)
 108 {
 109         int              pair[2];
 110         struct timeval   tv;
 111         char            *cause;
 112
 113         /* The first client is special and gets a socketpair; create it. */
 114         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 115                 fatal("socketpair failed");
 116
 117         switch (fork()) {
 118         case -1:
 119                 fatal("fork failed");
 120         case 0:
 121                 break;
 122         default:
 123                 close(pair[1]);
 124                 return (pair[0]);
 125         }
 126         close(pair[0]);
 127
 128         /*
 129          * Must daemonise before loading configuration as the PID changes so
 130          * $TMUX would be wrong for sessions created in the config file.
 131          */
 132         if (daemon(1, 0) != 0)
 133                 fatal("daemon failed");
 134
 135         /* event_init() was called in our parent, need to reinit. */
 136         if (event_reinit(ev_base) != 0)
 137                 fatal("event_reinit failed");
 138         clear_signals(0);
 139
 140         logfile("server");
 141         log_debug("server started, pid %ld", (long) getpid());
 142
 143         ARRAY_INIT(&windows);
 144         RB_INIT(&all_window_panes);
 145         ARRAY_INIT(&clients);
 146         ARRAY_INIT(&dead_clients);
 147         RB_INIT(&sessions);
 148         RB_INIT(&dead_sessions);
 149         TAILQ_INIT(&session_groups);
 150         ARRAY_INIT(&global_buffers);
 151         mode_key_init_trees();
 152         key_bindings_init();
 153         utf8_build();
 154
 155         start_time = time(NULL);
 156         log_debug("socket path %s", socket_path);
 157         setproctitle("server (%s)", socket_path);
 158
 159         server_fd = server_create_socket();
 160         server_client_create(pair[1]);
 161
 162         unlink(lockfile);
 163         free(lockfile);
 164         close(lockfd);
 165
 166         cfg_cmd_q = cmdq_new(NULL);
 167         cfg_cmd_q->emptyfn = cfg_default_done;
 168         cfg_finished = 0;
 169         cfg_references = 1;
 170         ARRAY_INIT(&cfg_causes);
 171         cfg_client = ARRAY_FIRST(&clients);
 172         if (cfg_client != NULL)
 173                 cfg_client->references++;
 174
 175         if (access(TMUX_CONF, R_OK) == 0) {
 176                 if (load_cfg(TMUX_CONF, cfg_cmd_q, &cause) == -1) {
 177                         xasprintf(&cause, "%s: %s", TMUX_CONF, cause);
 178                         ARRAY_ADD(&cfg_causes, cause);
 179                 }
 180         } else if (errno != ENOENT) {
 181                 xasprintf(&cause, "%s: %s", TMUX_CONF, strerror(errno));
 182                 ARRAY_ADD(&cfg_causes, cause);
 183         }
 184         if (cfg_file != NULL) {
 185                 if (load_cfg(cfg_file, cfg_cmd_q, &cause) == -1) {
 186                         xasprintf(&cause, "%s: %s", cfg_file, cause);
 187                         ARRAY_ADD(&cfg_causes, cause);
 188                 }
 189         }
 190         cmdq_continue(cfg_cmd_q);
 191
 192         server_add_accept(0);
 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                 if (!RB_EMPTY(&sessions))
 227                         return (0);
 228         }
 229         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 230                 if (ARRAY_ITEM(&clients, i) != NULL)
 231                         return (0);
 232         }
 233         return (1);
 234 }
 235
 236 /* Shutdown the server by killing all clients and windows. */
 237 void
 238 server_send_shutdown(void)
 239 {
 240         struct client   *c;
 241         struct session  *s, *next_s;
 242         u_int            i;
 243
 244         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 245                 c = ARRAY_ITEM(&clients, i);
 246                 if (c != NULL) {
 247                         if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
 248                                 server_client_lost(c);
 249                         else
 250                                 server_write_client(c, MSG_SHUTDOWN, NULL, 0);
 251                         c->session = NULL;
 252                 }
 253         }
 254
 255         s = RB_MIN(sessions, &sessions);
 256         while (s != NULL) {
 257                 next_s = RB_NEXT(sessions, &sessions, s);
 258                 session_destroy(s);
 259                 s = next_s;
 260         }
 261 }
 262
 263 /* Free dead, unreferenced clients and sessions. */
 264 void
 265 server_clean_dead(void)
 266 {
 267         struct session  *s, *next_s;
 268         struct client   *c;
 269         u_int            i;
 270
 271         s = RB_MIN(sessions, &dead_sessions);
 272         while (s != NULL) {
 273                 next_s = RB_NEXT(sessions, &dead_sessions, s);
 274                 if (s->references == 0) {
 275                         RB_REMOVE(sessions, &dead_sessions, s);
 276                         free(s->name);
 277                         free(s);
 278                 }
 279                 s = next_s;
 280         }
 281
 282         for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
 283                 c = ARRAY_ITEM(&dead_clients, i);
 284                 if (c == NULL || c->references != 0)
 285                         continue;
 286                 ARRAY_SET(&dead_clients, i, NULL);
 287                 free(c);
 288         }
 289 }
 290
 291 /* Update socket execute permissions based on whether sessions are attached. */
 292 void
 293 server_update_socket(void)
 294 {
 295         struct session  *s;
 296         static int       last = -1;
 297         int              n, mode;
 298         struct stat      sb;
 299
 300         n = 0;
 301         RB_FOREACH(s, sessions, &sessions) {
 302                 if (!(s->flags & SESSION_UNATTACHED)) {
 303                         n++;
 304                         break;
 305                 }
 306         }
 307
 308         if (n != last) {
 309                 last = n;
 310
 311                 if (stat(socket_path, &sb) != 0)
 312                         return;
 313                 mode = sb.st_mode;
 314                 if (n != 0) {
 315                         if (mode & S_IRUSR)
 316                                 mode |= S_IXUSR;
 317                         if (mode & S_IRGRP)
 318                                 mode |= S_IXGRP;
 319                         if (mode & S_IROTH)
 320                                 mode |= S_IXOTH;
 321                 } else
 322                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 323                 chmod(socket_path, mode);
 324         }
 325 }
 326
 327 /* Callback for server socket. */
 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         server_add_accept(0);
 336         if (!(events & EV_READ))
 337                 return;
 338
 339         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 340         if (newfd == -1) {
 341                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 342                         return;
 343                 if (errno == ENFILE || errno == EMFILE) {
 344                         /* Delete and don't try again for 1 second. */
 345                         server_add_accept(1);
 346                         return;
 347                 }
 348                 fatal("accept failed");
 349         }
 350         if (server_shutdown) {
 351                 close(newfd);
 352                 return;
 353         }
 354         server_client_create(newfd);
 355 }
 356
 357 /*
 358  * Add accept event. If timeout is nonzero, add as a timeout instead of a read
 359  * event - used to backoff when running out of file descriptors.
 360  */
 361 void
 362 server_add_accept(int timeout)
 363 {
 364         struct timeval tv = { timeout, 0 };
 365
 366         if (event_initialized(&server_ev_accept))
 367                 event_del(&server_ev_accept);
 368
 369         if (timeout == 0) {
 370                 event_set(&server_ev_accept,
 371                     server_fd, EV_READ, server_accept_callback, NULL);
 372                 event_add(&server_ev_accept, NULL);
 373         } else {
 374                 event_set(&server_ev_accept,
 375                     server_fd, EV_TIMEOUT, server_accept_callback, NULL);
 376                 event_add(&server_ev_accept, &tv);
 377         }
 378 }
 379
 380 /* Signal handler. */
 381 void
 382 server_signal_callback(int sig, unused short events, unused void *data)
 383 {
 384         switch (sig) {
 385         case SIGTERM:
 386                 server_shutdown = 1;
 387                 server_send_shutdown();
 388                 break;
 389         case SIGCHLD:
 390                 server_child_signal();
 391                 break;
 392         case SIGUSR1:
 393                 event_del(&server_ev_accept);
 394                 close(server_fd);
 395                 server_fd = server_create_socket();
 396                 server_add_accept(0);
 397                 break;
 398         }
 399 }
 400
 401 /* Handle SIGCHLD. */
 402 void
 403 server_child_signal(void)
 404 {
 405         int      status;
 406         pid_t    pid;
 407
 408         for (;;) {
 409                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 410                 case -1:
 411                         if (errno == ECHILD)
 412                                 return;
 413                         fatal("waitpid failed");
 414                 case 0:
 415                         return;
 416                 }
 417                 if (WIFSTOPPED(status))
 418                         server_child_stopped(pid, status);
 419                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 420                         server_child_exited(pid, status);
 421         }
 422 }
 423
 424 /* Handle exited children. */
 425 void
 426 server_child_exited(pid_t pid, int status)
 427 {
 428         struct window           *w;
 429         struct window_pane      *wp;
 430         struct job              *job;
 431         u_int                    i;
 432
 433         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 434                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 435                         continue;
 436                 TAILQ_FOREACH(wp, &w->panes, entry) {
 437                         if (wp->pid == pid) {
 438                                 server_destroy_pane(wp);
 439                                 break;
 440                         }
 441                 }
 442         }
 443
 444         LIST_FOREACH(job, &all_jobs, lentry) {
 445                 if (pid == job->pid) {
 446                         job_died(job, status);  /* might free job */
 447                         break;
 448                 }
 449         }
 450 }
 451
 452 /* Handle stopped children. */
 453 void
 454 server_child_stopped(pid_t pid, int status)
 455 {
 456         struct window           *w;
 457         struct window_pane      *wp;
 458         u_int                    i;
 459
 460         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 461                 return;
 462
 463         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 464                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 465                         continue;
 466                 TAILQ_FOREACH(wp, &w->panes, entry) {
 467                         if (wp->pid == pid) {
 468                                 if (killpg(pid, SIGCONT) != 0)
 469                                         kill(pid, SIGCONT);
 470                         }
 471                 }
 472         }
 473 }
 474
 475 /* Handle once-per-second timer events. */
 476 void
 477 server_second_callback(unused int fd, unused short events, unused void *arg)
 478 {
 479         struct window           *w;
 480         struct window_pane      *wp;
 481         struct timeval           tv;
 482         u_int                    i;
 483
 484         if (options_get_number(&global_s_options, "lock-server"))
 485                 server_lock_server();
 486         else
 487                 server_lock_sessions();
 488
 489         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 490                 w = ARRAY_ITEM(&windows, i);
 491                 if (w == NULL)
 492                         continue;
 493
 494                 TAILQ_FOREACH(wp, &w->panes, entry) {
 495                         if (wp->mode != NULL && wp->mode->timer != NULL)
 496                                 wp->mode->timer(wp);
 497                 }
 498         }
 499
 500         server_client_status_timer();
 501
 502         evtimer_del(&server_ev_second);
 503         memset(&tv, 0, sizeof tv);
 504         tv.tv_sec = 1;
 505         evtimer_add(&server_ev_second, &tv);
 506 }
 507
 508 /* Lock the server if ALL sessions have hit the time limit. */
 509 void
 510 server_lock_server(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                         return; /* not timed out */
 523         }
 524
 525         server_lock();
 526         recalculate_sizes();
 527 }
 528
 529 /* Lock any sessions which have timed out. */
 530 void
 531 server_lock_sessions(void)
 532 {
 533         struct session  *s;
 534         int              timeout;
 535         time_t           t;
 536
 537         t = time(NULL);
 538         RB_FOREACH(s, sessions, &sessions) {
 539                 if (s->flags & SESSION_UNATTACHED)
 540                         continue;
 541                 timeout = options_get_number(&s->options, "lock-after-time");
 542                 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 543                         server_lock_session(s);
 544                         recalculate_sizes();
 545                 }
 546         }
 547 }