external/bsd/tmux/dist/server.c

   1 /* Id */
   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 <signal.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <syslog.h>
  34 #include <termios.h>
  35 #include <time.h>
  36 #include <unistd.h>
  37
  38 #include "tmux.h"
  39
  40 /*
  41  * Main server functions.
  42  */
  43
  44 /* Client list. */
  45 struct clients   clients;
  46 struct clients   dead_clients;
  47
  48 int              server_fd;
  49 int              server_shutdown;
  50 struct event     server_ev_accept;
  51 struct event     server_ev_second;
  52
  53 struct paste_stack global_buffers;
  54
  55 int              server_create_socket(void);
  56 void             server_loop(void);
  57 int              server_should_shutdown(void);
  58 void             server_send_shutdown(void);
  59 void             server_clean_dead(void);
  60 void             server_accept_callback(int, short, void *);
  61 void             server_signal_callback(int, short, void *);
  62 void             server_child_signal(void);
  63 void             server_child_exited(pid_t, int);
  64 void             server_child_stopped(pid_t, int);
  65 void             server_second_callback(int, short, void *);
  66 void             server_lock_server(void);
  67 void             server_lock_sessions(void);
  68
  69 /* Create server socket. */
  70 int
  71 server_create_socket(void)
  72 {
  73         struct sockaddr_un      sa;
  74         size_t                  size;
  75         mode_t                  mask;
  76         int                     fd;
  77
  78         memset(&sa, 0, sizeof sa);
  79         sa.sun_family = AF_UNIX;
  80         size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path);
  81         if (size >= sizeof sa.sun_path) {
  82                 errno = ENAMETOOLONG;
  83                 fatal("socket failed");
  84         }
  85         unlink(sa.sun_path);
  86
  87         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
  88                 fatal("socket failed");
  89
  90         mask = umask(S_IXUSR|S_IXGRP|S_IRWXO);
  91         if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
  92                 fatal("bind failed");
  93         umask(mask);
  94
  95         if (listen(fd, 16) == -1)
  96                 fatal("listen failed");
  97         setblocking(fd, 0);
  98
  99         server_update_socket();
 100
 101         return (fd);
 102 }
 103
 104 /* Fork new server. */
 105 int
 106 server_start(int lockfd, char *lockfile)
 107 {
 108         int              pair[2];
 109         struct timeval   tv;
 110         char            *cause;
 111
 112         /* The first client is special and gets a socketpair; create it. */
 113         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 114                 fatal("socketpair failed");
 115
 116         switch (fork()) {
 117         case -1:
 118                 fatal("fork failed");
 119         case 0:
 120                 break;
 121         default:
 122                 close(pair[1]);
 123                 return (pair[0]);
 124         }
 125         close(pair[0]);
 126
 127         /*
 128          * Must daemonise before loading configuration as the PID changes so
 129          * $TMUX would be wrong for sessions created in the config file.
 130          */
 131         if (daemon(1, 0) != 0)
 132                 fatal("daemon failed");
 133
 134         /* event_init() was called in our parent, need to reinit. */
 135         if (event_reinit(ev_base) != 0)
 136                 fatal("event_reinit failed");
 137         clear_signals(0);
 138
 139         logfile("server");
 140         log_debug("server started, pid %ld", (long) getpid());
 141
 142         ARRAY_INIT(&windows);
 143         RB_INIT(&all_window_panes);
 144         ARRAY_INIT(&clients);
 145         ARRAY_INIT(&dead_clients);
 146         RB_INIT(&sessions);
 147         RB_INIT(&dead_sessions);
 148         TAILQ_INIT(&session_groups);
 149         ARRAY_INIT(&global_buffers);
 150         mode_key_init_trees();
 151         key_bindings_init();
 152         utf8_build();
 153
 154         start_time = time(NULL);
 155         log_debug("socket path %s", socket_path);
 156 #ifdef HAVE_SETPROCTITLE
 157         setproctitle("server (%s)", socket_path);
 158 #endif
 159
 160         server_fd = server_create_socket();
 161         server_client_create(pair[1]);
 162
 163         unlink(lockfile);
 164         free(lockfile);
 165         close(lockfd);
 166
 167         cfg_cmd_q = cmdq_new(NULL);
 168         cfg_cmd_q->emptyfn = cfg_default_done;
 169         cfg_finished = 0;
 170         cfg_references = 1;
 171         ARRAY_INIT(&cfg_causes);
 172         cfg_client = ARRAY_FIRST(&clients);
 173         if (cfg_client != NULL)
 174                 cfg_client->references++;
 175
 176         if (access(TMUX_CONF, R_OK) == 0) {
 177                 if (load_cfg(TMUX_CONF, cfg_cmd_q, &cause) == -1) {
 178                         xasprintf(&cause, "%s: %s", TMUX_CONF, cause);
 179                         ARRAY_ADD(&cfg_causes, cause);
 180                 }
 181         } else if (errno != ENOENT) {
 182                 xasprintf(&cause, "%s: %s", TMUX_CONF, strerror(errno));
 183                 ARRAY_ADD(&cfg_causes, cause);
 184         }
 185         if (cfg_file != NULL) {
 186                 if (load_cfg(cfg_file, cfg_cmd_q, &cause) == -1) {
 187                         xasprintf(&cause, "%s: %s", cfg_file, cause);
 188                         ARRAY_ADD(&cfg_causes, cause);
 189                 }
 190         }
 191         cmdq_continue(cfg_cmd_q);
 192
 193         server_add_accept(0);
 194
 195         memset(&tv, 0, sizeof tv);
 196         tv.tv_sec = 1;
 197         evtimer_set(&server_ev_second, server_second_callback, NULL);
 198         evtimer_add(&server_ev_second, &tv);
 199
 200         set_signals(server_signal_callback);
 201         server_loop();
 202         exit(0);
 203 }
 204
 205 /* Main server loop. */
 206 void
 207 server_loop(void)
 208 {
 209         while (!server_should_shutdown()) {
 210                 event_loop(EVLOOP_ONCE);
 211
 212                 server_window_loop();
 213                 server_client_loop();
 214
 215                 key_bindings_clean();
 216                 server_clean_dead();
 217         }
 218 }
 219
 220 /* Check if the server should be shutting down (no more clients or sessions). */
 221 int
 222 server_should_shutdown(void)
 223 {
 224         u_int   i;
 225
 226         if (!options_get_number(&global_options, "exit-unattached")) {
 227                 if (!RB_EMPTY(&sessions))
 228                         return (0);
 229         }
 230         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 231                 if (ARRAY_ITEM(&clients, i) != NULL)
 232                         return (0);
 233         }
 234         return (1);
 235 }
 236
 237 /* Shutdown the server by killing all clients and windows. */
 238 void
 239 server_send_shutdown(void)
 240 {
 241         struct client   *c;
 242         struct session  *s, *next_s;
 243         u_int            i;
 244
 245         for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 246                 c = ARRAY_ITEM(&clients, i);
 247                 if (c != NULL) {
 248                         if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
 249                                 server_client_lost(c);
 250                         else
 251                                 server_write_client(c, MSG_SHUTDOWN, NULL, 0);
 252                         c->session = NULL;
 253                 }
 254         }
 255
 256         s = RB_MIN(sessions, &sessions);
 257         while (s != NULL) {
 258                 next_s = RB_NEXT(sessions, &sessions, s);
 259                 session_destroy(s);
 260                 s = next_s;
 261         }
 262 }
 263
 264 /* Free dead, unreferenced clients and sessions. */
 265 void
 266 server_clean_dead(void)
 267 {
 268         struct session  *s, *next_s;
 269         struct client   *c;
 270         u_int            i;
 271
 272         s = RB_MIN(sessions, &dead_sessions);
 273         while (s != NULL) {
 274                 next_s = RB_NEXT(sessions, &dead_sessions, s);
 275                 if (s->references == 0) {
 276                         RB_REMOVE(sessions, &dead_sessions, s);
 277                         free(s->name);
 278                         free(s);
 279                 }
 280                 s = next_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                 free(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         static int       last = -1;
 298         int              n, mode;
 299         struct stat      sb;
 300
 301         n = 0;
 302         RB_FOREACH(s, sessions, &sessions) {
 303                 if (!(s->flags & SESSION_UNATTACHED)) {
 304                         n++;
 305                         break;
 306                 }
 307         }
 308
 309         if (n != last) {
 310                 last = n;
 311
 312                 if (stat(socket_path, &sb) != 0)
 313                         return;
 314                 mode = sb.st_mode;
 315                 if (n != 0) {
 316                         if (mode & S_IRUSR)
 317                                 mode |= S_IXUSR;
 318                         if (mode & S_IRGRP)
 319                                 mode |= S_IXGRP;
 320                         if (mode & S_IROTH)
 321                                 mode |= S_IXOTH;
 322                 } else
 323                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 324                 chmod(socket_path, mode);
 325         }
 326 }
 327
 328 /* Callback for server socket. */
 329 void
 330 server_accept_callback(int fd, short events, unused void *data)
 331 {
 332         struct sockaddr_storage sa;
 333         socklen_t               slen = sizeof sa;
 334         int                     newfd;
 335
 336         server_add_accept(0);
 337         if (!(events & EV_READ))
 338                 return;
 339
 340         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 341         if (newfd == -1) {
 342                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 343                         return;
 344                 if (errno == ENFILE || errno == EMFILE) {
 345                         /* Delete and don't try again for 1 second. */
 346                         server_add_accept(1);
 347                         return;
 348                 }
 349                 fatal("accept failed");
 350         }
 351         if (server_shutdown) {
 352                 close(newfd);
 353                 return;
 354         }
 355         server_client_create(newfd);
 356 }
 357
 358 /*
 359  * Add accept event. If timeout is nonzero, add as a timeout instead of a read
 360  * event - used to backoff when running out of file descriptors.
 361  */
 362 void
 363 server_add_accept(int timeout)
 364 {
 365         struct timeval tv = { timeout, 0 };
 366
 367         if (event_initialized(&server_ev_accept))
 368                 event_del(&server_ev_accept);
 369
 370         if (timeout == 0) {
 371                 event_set(&server_ev_accept,
 372                     server_fd, EV_READ, server_accept_callback, NULL);
 373                 event_add(&server_ev_accept, NULL);
 374         } else {
 375                 event_set(&server_ev_accept,
 376                     server_fd, EV_TIMEOUT, server_accept_callback, NULL);
 377                 event_add(&server_ev_accept, &tv);
 378         }
 379 }
 380
 381 /* Signal handler. */
 382 void
 383 server_signal_callback(int sig, unused short events, unused void *data)
 384 {
 385         switch (sig) {
 386         case SIGTERM:
 387                 server_shutdown = 1;
 388                 server_send_shutdown();
 389                 break;
 390         case SIGCHLD:
 391                 server_child_signal();
 392                 break;
 393         case SIGUSR1:
 394                 event_del(&server_ev_accept);
 395                 close(server_fd);
 396                 server_fd = server_create_socket();
 397                 server_add_accept(0);
 398                 break;
 399         }
 400 }
 401
 402 /* Handle SIGCHLD. */
 403 void
 404 server_child_signal(void)
 405 {
 406         int      status;
 407         pid_t    pid;
 408
 409         for (;;) {
 410                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 411                 case -1:
 412                         if (errno == ECHILD)
 413                                 return;
 414                         fatal("waitpid failed");
 415                 case 0:
 416                         return;
 417                 }
 418                 if (WIFSTOPPED(status))
 419                         server_child_stopped(pid, status);
 420                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 421                         server_child_exited(pid, status);
 422         }
 423 }
 424
 425 /* Handle exited children. */
 426 void
 427 server_child_exited(pid_t pid, int status)
 428 {
 429         struct window           *w;
 430         struct window_pane      *wp;
 431         struct job              *job;
 432         u_int                    i;
 433
 434         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 435                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 436                         continue;
 437                 TAILQ_FOREACH(wp, &w->panes, entry) {
 438                         if (wp->pid == pid) {
 439                                 server_destroy_pane(wp);
 440                                 break;
 441                         }
 442                 }
 443         }
 444
 445         LIST_FOREACH(job, &all_jobs, lentry) {
 446                 if (pid == job->pid) {
 447                         job_died(job, status);  /* might free job */
 448                         break;
 449                 }
 450         }
 451 }
 452
 453 /* Handle stopped children. */
 454 void
 455 server_child_stopped(pid_t pid, int status)
 456 {
 457         struct window           *w;
 458         struct window_pane      *wp;
 459         u_int                    i;
 460
 461         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 462                 return;
 463
 464         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 465                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 466                         continue;
 467                 TAILQ_FOREACH(wp, &w->panes, entry) {
 468                         if (wp->pid == pid) {
 469                                 if (killpg(pid, SIGCONT) != 0)
 470                                         kill(pid, SIGCONT);
 471                         }
 472                 }
 473         }
 474 }
 475
 476 /* Handle once-per-second timer events. */
 477 void
 478 server_second_callback(unused int fd, unused short events, unused void *arg)
 479 {
 480         struct window           *w;
 481         struct window_pane      *wp;
 482         struct timeval           tv;
 483         u_int                    i;
 484
 485         if (options_get_number(&global_s_options, "lock-server"))
 486                 server_lock_server();
 487         else
 488                 server_lock_sessions();
 489
 490         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 491                 w = ARRAY_ITEM(&windows, i);
 492                 if (w == NULL)
 493                         continue;
 494
 495                 TAILQ_FOREACH(wp, &w->panes, entry) {
 496                         if (wp->mode != NULL && wp->mode->timer != NULL)
 497                                 wp->mode->timer(wp);
 498                 }
 499         }
 500
 501         server_client_status_timer();
 502
 503         evtimer_del(&server_ev_second);
 504         memset(&tv, 0, sizeof tv);
 505         tv.tv_sec = 1;
 506         evtimer_add(&server_ev_second, &tv);
 507 }
 508
 509 /* Lock the server if ALL sessions have hit the time limit. */
 510 void
 511 server_lock_server(void)
 512 {
 513         struct session  *s;
 514         int              timeout;
 515         time_t           t;
 516
 517         t = time(NULL);
 518         RB_FOREACH(s, sessions, &sessions) {
 519                 if (s->flags & SESSION_UNATTACHED)
 520                         continue;
 521                 timeout = options_get_number(&s->options, "lock-after-time");
 522                 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
 523                         return; /* not timed out */
 524         }
 525
 526         server_lock();
 527         recalculate_sizes();
 528 }
 529
 530 /* Lock any sessions which have timed out. */
 531 void
 532 server_lock_sessions(void)
 533 {
 534         struct session  *s;
 535         int              timeout;
 536         time_t           t;
 537
 538         t = time(NULL);
 539         RB_FOREACH(s, sessions, &sessions) {
 540                 if (s->flags & SESSION_UNATTACHED)
 541                         continue;
 542                 timeout = options_get_number(&s->options, "lock-after-time");
 543                 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 544                         server_lock_session(s);
 545                         recalculate_sizes();
 546                 }
 547         }
 548 }