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_sigterm;
  53 struct event     server_ev_sigusr1;
  54 struct event     server_ev_sigchld;
  55 struct event     server_ev_second;
  56
  57 int              server_create_socket(void);
  58 void             server_loop(void);
  59 int              server_should_shutdown(void);
  60 void             server_send_shutdown(void);
  61 void             server_clean_dead(void);
  62 void             server_accept_callback(int, short, void *);
  63 void             server_signal_callback(int, short, void *);
  64 void             server_child_signal(void);
  65 void             server_child_exited(pid_t, int);
  66 void             server_child_stopped(pid_t, int);
  67 void             server_second_callback(int, short, void *);
  68 void             server_lock_server(void);
  69 void             server_lock_sessions(void);
  70
  71 /* Create server socket. */
  72 int
  73 server_create_socket(void)
  74 {
  75         struct sockaddr_un      sa;
  76         size_t                  size;
  77         mode_t                  mask;
  78         int                     fd, mode;
  79
  80         memset(&sa, 0, sizeof sa);
  81         sa.sun_family = AF_UNIX;
  82         size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path);
  83         if (size >= sizeof sa.sun_path) {
  84                 errno = ENAMETOOLONG;
  85                 fatal("socket failed");
  86         }
  87         unlink(sa.sun_path);
  88
  89         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
  90                 fatal("socket failed");
  91
  92         mask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
  93         if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
  94                 fatal("bind failed");
  95         umask(mask);
  96
  97         if (listen(fd, 16) == -1)
  98                 fatal("listen failed");
  99
 100         if ((mode = fcntl(fd, F_GETFL)) == -1)
 101                 fatal("fcntl failed");
 102         if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1)
 103                 fatal("fcntl failed");
 104         if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
 105                 fatal("fcntl failed");
 106
 107         server_update_socket();
 108
 109         return (fd);
 110 }
 111
 112 /* Fork new server. */
 113 int
 114 server_start(char *path)
 115 {
 116         struct client   *c;
 117         int              pair[2];
 118         char            *cause, rpathbuf[MAXPATHLEN];
 119         struct timeval   tv;
 120
 121         /* The first client is special and gets a socketpair; create it. */
 122         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 123                 fatal("socketpair failed");
 124
 125         switch (fork()) {
 126         case -1:
 127                 fatal("fork failed");
 128         case 0:
 129                 break;
 130         default:
 131                 close(pair[1]);
 132                 return (pair[0]);
 133         }
 134         close(pair[0]);
 135
 136         /*
 137          * Must daemonise before loading configuration as the PID changes so
 138          * $TMUX would be wrong for sessions created in the config file.
 139          */
 140         if (daemon(1, 0) != 0)
 141                 fatal("daemon failed");
 142
 143         logfile("server");
 144         log_debug("server started, pid %ld", (long) getpid());
 145
 146         ARRAY_INIT(&windows);
 147         ARRAY_INIT(&clients);
 148         ARRAY_INIT(&dead_clients);
 149         ARRAY_INIT(&sessions);
 150         ARRAY_INIT(&dead_sessions);
 151         TAILQ_INIT(&session_groups);
 152         mode_key_init_trees();
 153         key_bindings_init();
 154         utf8_build();
 155
 156         start_time = time(NULL);
 157         socket_path = path;
 158
 159         if (realpath(socket_path, rpathbuf) == NULL)
 160                 strlcpy(rpathbuf, socket_path, sizeof rpathbuf);
 161         log_debug("socket path %s", socket_path);
 162         setproctitle("server (%s)", rpathbuf);
 163
 164         event_init();
 165
 166         server_fd = server_create_socket();
 167         server_client_create(pair[1]);
 168
 169         if (access(SYSTEM_CFG, R_OK) == 0) {
 170                 if (load_cfg(SYSTEM_CFG, NULL, &cause) != 0)
 171                         goto error;
 172         } else if (errno != ENOENT) {
 173                 xasprintf(&cause, "%s: %s", strerror(errno), SYSTEM_CFG);
 174                 goto error;
 175         }
 176         if (cfg_file != NULL && load_cfg(cfg_file, NULL, &cause) != 0)
 177                 goto error;
 178
 179         event_set(&server_ev_accept,
 180             server_fd, EV_READ|EV_PERSIST, server_accept_callback, NULL);
 181         event_add(&server_ev_accept, NULL);
 182
 183         memset(&tv, 0, sizeof tv);
 184         tv.tv_sec = 1;
 185         evtimer_set(&server_ev_second, server_second_callback, NULL);
 186         evtimer_add(&server_ev_second, &tv);
 187
 188         server_signal_set();
 189         server_loop();
 190         exit(0);
 191
 192 error:
 193         /* Write the error and shutdown the server. */
 194         c = ARRAY_FIRST(&clients);
 195
 196         server_write_error(c, cause);
 197         server_write_client(c, MSG_EXIT, NULL, 0);
 198         xfree(cause);
 199
 200         server_shutdown = 1;
 201
 202         server_signal_set();
 203         server_loop();
 204         exit(1);
 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 windows). */
 223 int
 224 server_should_shutdown(void)
 225 {
 226         u_int   i;
 227
 228         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 229                 if (ARRAY_ITEM(&sessions, i) != NULL)
 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;
 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         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 259                 if ((s = ARRAY_ITEM(&sessions, i)) != NULL)
 260                         session_destroy(s);
 261         }
 262 }
 263
 264 /* Free dead, unreferenced clients and sessions. */
 265 void
 266 server_clean_dead(void)
 267 {
 268         struct session  *s;
 269         struct client   *c;
 270         u_int            i;
 271
 272         for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
 273                 s = ARRAY_ITEM(&dead_sessions, i);
 274                 if (s == NULL || s->references != 0)
 275                         continue;
 276                 ARRAY_SET(&dead_sessions, i, NULL);
 277                 xfree(s);
 278         }
 279
 280         for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
 281                 c = ARRAY_ITEM(&dead_clients, i);
 282                 if (c == NULL || c->references != 0)
 283                         continue;
 284                 ARRAY_SET(&dead_clients, i, NULL);
 285                 xfree(c);
 286         }
 287 }
 288
 289 /* Update socket execute permissions based on whether sessions are attached. */
 290 void
 291 server_update_socket(void)
 292 {
 293         struct session  *s;
 294         u_int            i;
 295         static int       last = -1;
 296         int              n;
 297
 298         n = 0;
 299         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 300                 s = ARRAY_ITEM(&sessions, i);
 301                 if (s != NULL && !(s->flags & SESSION_UNATTACHED)) {
 302                         n++;
 303                         break;
 304                 }
 305         }
 306
 307         if (n != last) {
 308                 last = n;
 309                 if (n != 0)
 310                         chmod(socket_path, S_IRWXU);
 311                 else
 312                         chmod(socket_path, S_IRUSR|S_IWUSR);
 313         }
 314 }
 315
 316 /* Callback for server socket. */
 317 /* ARGSUSED */
 318 void
 319 server_accept_callback(int fd, short events, unused void *data)
 320 {
 321         struct sockaddr_storage sa;
 322         socklen_t               slen = sizeof sa;
 323         int                     newfd;
 324
 325         if (!(events & EV_READ))
 326                 return;
 327
 328         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 329         if (newfd == -1) {
 330                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 331                         return;
 332                 fatal("accept failed");
 333         }
 334         if (server_shutdown) {
 335                 close(newfd);
 336                 return;
 337         }
 338         server_client_create(newfd);
 339 }
 340
 341 /* Set up server signal handling. */
 342 void
 343 server_signal_set(void)
 344 {
 345         struct sigaction         sigact;
 346
 347         memset(&sigact, 0, sizeof sigact);
 348         sigemptyset(&sigact.sa_mask);
 349         sigact.sa_flags = SA_RESTART;
 350         sigact.sa_handler = SIG_IGN;
 351         if (sigaction(SIGINT, &sigact, NULL) != 0)
 352                 fatal("sigaction failed");
 353         if (sigaction(SIGPIPE, &sigact, NULL) != 0)
 354                 fatal("sigaction failed");
 355         if (sigaction(SIGUSR2, &sigact, NULL) != 0)
 356                 fatal("sigaction failed");
 357         if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 358                 fatal("sigaction failed");
 359
 360         signal_set(&server_ev_sigchld, SIGCHLD, server_signal_callback, NULL);
 361         signal_add(&server_ev_sigchld, NULL);
 362         signal_set(&server_ev_sigterm, SIGTERM, server_signal_callback, NULL);
 363         signal_add(&server_ev_sigterm, NULL);
 364         signal_set(&server_ev_sigusr1, SIGUSR1, server_signal_callback, NULL);
 365         signal_add(&server_ev_sigusr1, NULL);
 366 }
 367
 368 /* Destroy server signal events. */
 369 void
 370 server_signal_clear(void)
 371 {
 372         struct sigaction         sigact;
 373
 374         memset(&sigact, 0, sizeof sigact);
 375         sigemptyset(&sigact.sa_mask);
 376         sigact.sa_flags = SA_RESTART;
 377         sigact.sa_handler = SIG_DFL;
 378         if (sigaction(SIGINT, &sigact, NULL) != 0)
 379                 fatal("sigaction failed");
 380         if (sigaction(SIGPIPE, &sigact, NULL) != 0)
 381                 fatal("sigaction failed");
 382         if (sigaction(SIGUSR2, &sigact, NULL) != 0)
 383                 fatal("sigaction failed");
 384         if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 385                 fatal("sigaction failed");
 386
 387         signal_del(&server_ev_sigchld);
 388         signal_del(&server_ev_sigterm);
 389         signal_del(&server_ev_sigusr1);
 390 }
 391
 392 /* Signal handler. */
 393 /* ARGSUSED */
 394 void
 395 server_signal_callback(int sig, unused short events, unused void *data)
 396 {
 397         switch (sig) {
 398         case SIGTERM:
 399                 server_shutdown = 1;
 400                 server_send_shutdown();
 401                 break;
 402         case SIGCHLD:
 403                 server_child_signal();
 404                 break;
 405         case SIGUSR1:
 406                 event_del(&server_ev_accept);
 407                 close(server_fd);
 408                 server_fd = server_create_socket();
 409                 event_set(&server_ev_accept, server_fd,
 410                     EV_READ|EV_PERSIST, server_accept_callback, NULL);
 411                 event_add(&server_ev_accept, NULL);
 412                 break;
 413         }
 414 }
 415
 416 /* Handle SIGCHLD. */
 417 void
 418 server_child_signal(void)
 419 {
 420         int      status;
 421         pid_t    pid;
 422
 423         for (;;) {
 424                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 425                 case -1:
 426                         if (errno == ECHILD)
 427                                 return;
 428                         fatal("waitpid failed");
 429                 case 0:
 430                         return;
 431                 }
 432                 if (WIFSTOPPED(status))
 433                         server_child_stopped(pid, status);
 434                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 435                         server_child_exited(pid, status);
 436         }
 437 }
 438
 439 /* Handle exited children. */
 440 void
 441 server_child_exited(pid_t pid, int status)
 442 {
 443         struct window           *w;
 444         struct window_pane      *wp;
 445         struct job              *job;
 446         u_int                    i;
 447
 448         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 449                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 450                         continue;
 451                 TAILQ_FOREACH(wp, &w->panes, entry) {
 452                         if (wp->pid == pid) {
 453                                 server_destroy_pane(wp);
 454                                 break;
 455                         }
 456                 }
 457         }
 458
 459         SLIST_FOREACH(job, &all_jobs, lentry) {
 460                 if (pid == job->pid) {
 461                         job_died(job, status);  /* might free job */
 462                         break;
 463                 }
 464         }
 465 }
 466
 467 /* Handle stopped children. */
 468 void
 469 server_child_stopped(pid_t pid, int status)
 470 {
 471         struct window           *w;
 472         struct window_pane      *wp;
 473         u_int                    i;
 474
 475         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 476                 return;
 477
 478         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 479                 if ((w = ARRAY_ITEM(&windows, i)) == NULL)
 480                         continue;
 481                 TAILQ_FOREACH(wp, &w->panes, entry) {
 482                         if (wp->pid == pid) {
 483                                 if (killpg(pid, SIGCONT) != 0)
 484                                         kill(pid, SIGCONT);
 485                         }
 486                 }
 487         }
 488 }
 489
 490 /* Handle once-per-second timer events. */
 491 /* ARGSUSED */
 492 void
 493 server_second_callback(unused int fd, unused short events, unused void *arg)
 494 {
 495         struct window           *w;
 496         struct window_pane      *wp;
 497         struct timeval           tv;
 498         u_int                    i;
 499
 500         if (options_get_number(&global_s_options, "lock-server"))
 501                 server_lock_server();
 502         else
 503                 server_lock_sessions();
 504
 505         for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
 506                 w = ARRAY_ITEM(&windows, i);
 507                 if (w == NULL)
 508                         continue;
 509
 510                 TAILQ_FOREACH(wp, &w->panes, entry) {
 511                         if (wp->mode != NULL && wp->mode->timer != NULL)
 512                                 wp->mode->timer(wp);
 513                 }
 514         }
 515
 516         server_client_status_timer();
 517
 518         evtimer_del(&server_ev_second);
 519         memset(&tv, 0, sizeof tv);
 520         tv.tv_sec = 1;
 521         evtimer_add(&server_ev_second, &tv);
 522 }
 523
 524 /* Lock the server if ALL sessions have hit the time limit. */
 525 void
 526 server_lock_server(void)
 527 {
 528         struct session  *s;
 529         u_int            i;
 530         int              timeout;
 531         time_t           t;
 532
 533         t = time(NULL);
 534         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 535                 if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
 536                         continue;
 537
 538                 if (s->flags & SESSION_UNATTACHED) {
 539                         if (gettimeofday(&s->activity_time, NULL) != 0)
 540                                 fatal("gettimeofday failed");
 541                         continue;
 542                 }
 543
 544                 timeout = options_get_number(&s->options, "lock-after-time");
 545                 if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
 546                         return; /* not timed out */
 547         }
 548
 549         server_lock();
 550         recalculate_sizes();
 551 }
 552
 553 /* Lock any sessions which have timed out. */
 554 void
 555 server_lock_sessions(void)
 556 {
 557         struct session  *s;
 558         u_int            i;
 559         int              timeout;
 560         time_t           t;
 561
 562         t = time(NULL);
 563         for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 564                 if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
 565                         continue;
 566
 567                 if (s->flags & SESSION_UNATTACHED) {
 568                         if (gettimeofday(&s->activity_time, NULL) != 0)
 569                                 fatal("gettimeofday failed");
 570                         continue;
 571                 }
 572
 573                 timeout = options_get_number(&s->options, "lock-after-time");
 574                 if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 575                         server_lock_session(s);
 576                         recalculate_sizes();
 577                 }
 578         }
 579 }