server.c

   1 /* $OpenBSD$ */
   2
   3 /*
   4  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
   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 <termios.h>
  35 #include <time.h>
  36 #include <unistd.h>
  37
  38 #include "tmux.h"
  39
  40 /*
  41  * Main server functions.
  42  */
  43
  44 struct clients           clients;
  45
  46 struct tmuxproc         *server_proc;
  47 static int               server_fd = -1;
  48 static uint64_t          server_client_flags;
  49 static int               server_exit;
  50 static struct event      server_ev_accept;
  51 static struct event      server_ev_tidy;
  52
  53 struct cmd_find_state    marked_pane;
  54
  55 static u_int             message_next;
  56 struct message_list      message_log;
  57
  58 static int      server_loop(void);
  59 static void     server_send_exit(void);
  60 static void     server_accept(int, short, void *);
  61 static void     server_signal(int);
  62 static void     server_child_signal(void);
  63 static void     server_child_exited(pid_t, int);
  64 static void     server_child_stopped(pid_t, int);
  65
  66 /* Set marked pane. */
  67 void
  68 server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp)
  69 {
  70         cmd_find_clear_state(&marked_pane, 0);
  71         marked_pane.s = s;
  72         marked_pane.wl = wl;
  73         marked_pane.w = wl->window;
  74         marked_pane.wp = wp;
  75 }
  76
  77 /* Clear marked pane. */
  78 void
  79 server_clear_marked(void)
  80 {
  81         cmd_find_clear_state(&marked_pane, 0);
  82 }
  83
  84 /* Is this the marked pane? */
  85 int
  86 server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp)
  87 {
  88         if (s == NULL || wl == NULL || wp == NULL)
  89                 return (0);
  90         if (marked_pane.s != s || marked_pane.wl != wl)
  91                 return (0);
  92         if (marked_pane.wp != wp)
  93                 return (0);
  94         return (server_check_marked());
  95 }
  96
  97 /* Check if the marked pane is still valid. */
  98 int
  99 server_check_marked(void)
 100 {
 101         return (cmd_find_valid_state(&marked_pane));
 102 }
 103
 104 /* Create server socket. */
 105 static int
 106 server_create_socket(int flags, char **cause)
 107 {
 108         struct sockaddr_un      sa;
 109         size_t                  size;
 110         mode_t                  mask;
 111         int                     fd, saved_errno;
 112
 113         memset(&sa, 0, sizeof sa);
 114         sa.sun_family = AF_UNIX;
 115         size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path);
 116         if (size >= sizeof sa.sun_path) {
 117                 errno = ENAMETOOLONG;
 118                 goto fail;
 119         }
 120         unlink(sa.sun_path);
 121
 122         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
 123                 goto fail;
 124
 125         if (flags & CLIENT_DEFAULTSOCKET)
 126                 mask = umask(S_IXUSR|S_IXGRP|S_IRWXO);
 127         else
 128                 mask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
 129         if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
 130                 saved_errno = errno;
 131                 close(fd);
 132                 errno = saved_errno;
 133                 goto fail;
 134         }
 135         umask(mask);
 136
 137         if (listen(fd, 128) == -1) {
 138                 saved_errno = errno;
 139                 close(fd);
 140                 errno = saved_errno;
 141                 goto fail;
 142         }
 143         setblocking(fd, 0);
 144
 145         return (fd);
 146
 147 fail:
 148         if (cause != NULL) {
 149                 xasprintf(cause, "error creating %s (%s)", socket_path,
 150                     strerror(errno));
 151         }
 152         return (-1);
 153 }
 154
 155 /* Tidy up every hour. */
 156 static void
 157 server_tidy_event(__unused int fd, __unused short events, __unused void *data)
 158 {
 159     struct timeval      tv = { .tv_sec = 3600 };
 160     uint64_t            t = get_timer();
 161
 162     format_tidy_jobs();
 163
 164     log_debug("%s: took %llu milliseconds", __func__,
 165         (unsigned long long)(get_timer() - t));
 166     evtimer_add(&server_ev_tidy, &tv);
 167 }
 168
 169 /* Fork new server. */
 170 int
 171 server_start(struct tmuxproc *client, int flags, struct event_base *base,
 172     int lockfd, char *lockfile)
 173 {
 174         int              fd;
 175         sigset_t         set, oldset;
 176         struct client   *c = NULL;
 177         char            *cause = NULL;
 178         struct timeval   tv = { .tv_sec = 3600 };
 179
 180         sigfillset(&set);
 181         sigprocmask(SIG_BLOCK, &set, &oldset);
 182
 183         if (~flags & CLIENT_NOFORK) {
 184                 if (proc_fork_and_daemon(&fd) != 0) {
 185                         sigprocmask(SIG_SETMASK, &oldset, NULL);
 186                         return (fd);
 187                 }
 188         }
 189         proc_clear_signals(client, 0);
 190         server_client_flags = flags;
 191
 192         if (event_reinit(base) != 0)
 193                 fatalx("event_reinit failed");
 194         server_proc = proc_start("server");
 195
 196         proc_set_signals(server_proc, server_signal);
 197         sigprocmask(SIG_SETMASK, &oldset, NULL);
 198
 199         if (log_get_level() > 1)
 200                 tty_create_log();
 201         if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec "
 202             "tty ps", NULL) != 0)
 203                 fatal("pledge failed");
 204
 205         input_key_build();
 206         RB_INIT(&windows);
 207         RB_INIT(&all_window_panes);
 208         TAILQ_INIT(&clients);
 209         RB_INIT(&sessions);
 210         key_bindings_init();
 211         TAILQ_INIT(&message_log);
 212
 213         gettimeofday(&start_time, NULL);
 214
 215         server_fd = server_create_socket(flags, &cause);
 216         if (server_fd != -1)
 217                 server_update_socket();
 218         if (~flags & CLIENT_NOFORK)
 219                 c = server_client_create(fd);
 220         else
 221                 options_set_number(global_options, "exit-empty", 0);
 222
 223         if (lockfd >= 0) {
 224                 unlink(lockfile);
 225                 free(lockfile);
 226                 close(lockfd);
 227         }
 228
 229         if (cause != NULL) {
 230                 if (c != NULL) {
 231                         c->exit_message = cause;
 232                         c->flags |= CLIENT_EXIT;
 233                 } else {
 234                         fprintf(stderr, "%s\n", cause);
 235                         exit(1);
 236                 }
 237         }
 238
 239         evtimer_set(&server_ev_tidy, server_tidy_event, NULL);
 240         evtimer_add(&server_ev_tidy, &tv);
 241
 242         server_acl_init();
 243
 244         server_add_accept(0);
 245         proc_loop(server_proc, server_loop);
 246
 247         job_kill_all();
 248         status_prompt_save_history();
 249
 250         exit(0);
 251 }
 252
 253 /* Server loop callback. */
 254 static int
 255 server_loop(void)
 256 {
 257         struct client   *c;
 258         u_int            items;
 259
 260         do {
 261                 items = cmdq_next(NULL);
 262                 TAILQ_FOREACH(c, &clients, entry) {
 263                         if (c->flags & CLIENT_IDENTIFIED)
 264                                 items += cmdq_next(c);
 265                 }
 266         } while (items != 0);
 267
 268         server_client_loop();
 269
 270         if (!options_get_number(global_options, "exit-empty") && !server_exit)
 271                 return (0);
 272
 273         if (!options_get_number(global_options, "exit-unattached")) {
 274                 if (!RB_EMPTY(&sessions))
 275                         return (0);
 276         }
 277
 278         TAILQ_FOREACH(c, &clients, entry) {
 279                 if (c->session != NULL)
 280                         return (0);
 281         }
 282
 283         /*
 284          * No attached clients therefore want to exit - flush any waiting
 285          * clients but don't actually exit until they've gone.
 286          */
 287         cmd_wait_for_flush();
 288         if (!TAILQ_EMPTY(&clients))
 289                 return (0);
 290
 291         if (job_still_running())
 292                 return (0);
 293
 294         return (1);
 295 }
 296
 297 /* Exit the server by killing all clients and windows. */
 298 static void
 299 server_send_exit(void)
 300 {
 301         struct client   *c, *c1;
 302         struct session  *s, *s1;
 303
 304         cmd_wait_for_flush();
 305
 306         TAILQ_FOREACH_SAFE(c, &clients, entry, c1) {
 307                 if (c->flags & CLIENT_SUSPENDED)
 308                         server_client_lost(c);
 309                 else {
 310                         c->flags |= CLIENT_EXIT;
 311                         c->exit_type = CLIENT_EXIT_SHUTDOWN;
 312                 }
 313                 c->session = NULL;
 314         }
 315
 316         RB_FOREACH_SAFE(s, sessions, &sessions, s1)
 317                 session_destroy(s, 1, __func__);
 318 }
 319
 320 /* Update socket execute permissions based on whether sessions are attached. */
 321 void
 322 server_update_socket(void)
 323 {
 324         struct session  *s;
 325         static int       last = -1;
 326         int              n, mode;
 327         struct stat      sb;
 328
 329         n = 0;
 330         RB_FOREACH(s, sessions, &sessions) {
 331                 if (s->attached != 0) {
 332                         n++;
 333                         break;
 334                 }
 335         }
 336
 337         if (n != last) {
 338                 last = n;
 339
 340                 if (stat(socket_path, &sb) != 0)
 341                         return;
 342                 mode = sb.st_mode & ACCESSPERMS;
 343                 if (n != 0) {
 344                         if (mode & S_IRUSR)
 345                                 mode |= S_IXUSR;
 346                         if (mode & S_IRGRP)
 347                                 mode |= S_IXGRP;
 348                         if (mode & S_IROTH)
 349                                 mode |= S_IXOTH;
 350                 } else
 351                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 352                 chmod(socket_path, mode);
 353         }
 354 }
 355
 356 /* Callback for server socket. */
 357 static void
 358 server_accept(int fd, short events, __unused void *data)
 359 {
 360         struct sockaddr_storage  sa;
 361         socklen_t                slen = sizeof sa;
 362         int                      newfd;
 363         struct client           *c;
 364
 365         server_add_accept(0);
 366         if (!(events & EV_READ))
 367                 return;
 368
 369         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 370         if (newfd == -1) {
 371                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 372                         return;
 373                 if (errno == ENFILE || errno == EMFILE) {
 374                         /* Delete and don't try again for 1 second. */
 375                         server_add_accept(1);
 376                         return;
 377                 }
 378                 fatal("accept failed");
 379         }
 380
 381         if (server_exit) {
 382                 close(newfd);
 383                 return;
 384         }
 385         c = server_client_create(newfd);
 386         if (!server_acl_join(c)) {
 387                 c->exit_message = xstrdup("access not allowed");
 388                 c->flags |= CLIENT_EXIT;
 389         }
 390 }
 391
 392 /*
 393  * Add accept event. If timeout is nonzero, add as a timeout instead of a read
 394  * event - used to backoff when running out of file descriptors.
 395  */
 396 void
 397 server_add_accept(int timeout)
 398 {
 399         struct timeval tv = { timeout, 0 };
 400
 401         if (server_fd == -1)
 402                 return;
 403
 404         if (event_initialized(&server_ev_accept))
 405                 event_del(&server_ev_accept);
 406
 407         if (timeout == 0) {
 408                 event_set(&server_ev_accept, server_fd, EV_READ, server_accept,
 409                     NULL);
 410                 event_add(&server_ev_accept, NULL);
 411         } else {
 412                 event_set(&server_ev_accept, server_fd, EV_TIMEOUT,
 413                     server_accept, NULL);
 414                 event_add(&server_ev_accept, &tv);
 415         }
 416 }
 417
 418 /* Signal handler. */
 419 static void
 420 server_signal(int sig)
 421 {
 422         int     fd;
 423
 424         log_debug("%s: %s", __func__, strsignal(sig));
 425         switch (sig) {
 426         case SIGINT:
 427         case SIGTERM:
 428                 server_exit = 1;
 429                 server_send_exit();
 430                 break;
 431         case SIGCHLD:
 432                 server_child_signal();
 433                 break;
 434         case SIGUSR1:
 435                 event_del(&server_ev_accept);
 436                 fd = server_create_socket(server_client_flags, NULL);
 437                 if (fd != -1) {
 438                         close(server_fd);
 439                         server_fd = fd;
 440                         server_update_socket();
 441                 }
 442                 server_add_accept(0);
 443                 break;
 444         case SIGUSR2:
 445                 proc_toggle_log(server_proc);
 446                 break;
 447         }
 448 }
 449
 450 /* Handle SIGCHLD. */
 451 static void
 452 server_child_signal(void)
 453 {
 454         int      status;
 455         pid_t    pid;
 456
 457         for (;;) {
 458                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 459                 case -1:
 460                         if (errno == ECHILD)
 461                                 return;
 462                         fatal("waitpid failed");
 463                 case 0:
 464                         return;
 465                 }
 466                 if (WIFSTOPPED(status))
 467                         server_child_stopped(pid, status);
 468                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 469                         server_child_exited(pid, status);
 470         }
 471 }
 472
 473 /* Handle exited children. */
 474 static void
 475 server_child_exited(pid_t pid, int status)
 476 {
 477         struct window           *w, *w1;
 478         struct window_pane      *wp;
 479
 480         RB_FOREACH_SAFE(w, windows, &windows, w1) {
 481                 TAILQ_FOREACH(wp, &w->panes, entry) {
 482                         if (wp->pid == pid) {
 483                                 wp->status = status;
 484                                 wp->flags |= PANE_STATUSREADY;
 485
 486                                 log_debug("%%%u exited", wp->id);
 487                                 wp->flags |= PANE_EXITED;
 488
 489                                 if (window_pane_destroy_ready(wp))
 490                                         server_destroy_pane(wp, 1);
 491                                 break;
 492                         }
 493                 }
 494         }
 495         job_check_died(pid, status);
 496 }
 497
 498 /* Handle stopped children. */
 499 static void
 500 server_child_stopped(pid_t pid, int status)
 501 {
 502         struct window           *w;
 503         struct window_pane      *wp;
 504
 505         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 506                 return;
 507
 508         RB_FOREACH(w, windows, &windows) {
 509                 TAILQ_FOREACH(wp, &w->panes, entry) {
 510                         if (wp->pid == pid) {
 511                                 if (killpg(pid, SIGCONT) != 0)
 512                                         kill(pid, SIGCONT);
 513                         }
 514                 }
 515         }
 516         job_check_died(pid, status);
 517 }
 518
 519 /* Add to message log. */
 520 void
 521 server_add_message(const char *fmt, ...)
 522 {
 523         struct message_entry    *msg, *msg1;
 524         char                    *s;
 525         va_list                  ap;
 526         u_int                    limit;
 527
 528         va_start(ap, fmt);
 529         xvasprintf(&s, fmt, ap);
 530         va_end(ap);
 531
 532         log_debug("message: %s", s);
 533
 534         msg = xcalloc(1, sizeof *msg);
 535         gettimeofday(&msg->msg_time, NULL);
 536         msg->msg_num = message_next++;
 537         msg->msg = s;
 538         TAILQ_INSERT_TAIL(&message_log, msg, entry);
 539
 540         limit = options_get_number(global_options, "message-limit");
 541         TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) {
 542                 if (msg->msg_num + limit >= message_next)
 543                         break;
 544                 free(msg->msg);
 545                 TAILQ_REMOVE(&message_log, msg, entry);
 546                 free(msg);
 547         }
 548 }