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                         cmdq_append(c, cmdq_get_error(cause));
 232                         c->flags |= CLIENT_EXIT;
 233                 }
 234                 free(cause);
 235         }
 236
 237         evtimer_set(&server_ev_tidy, server_tidy_event, NULL);
 238         evtimer_add(&server_ev_tidy, &tv);
 239
 240         server_add_accept(0);
 241         proc_loop(server_proc, server_loop);
 242
 243         job_kill_all();
 244         status_prompt_save_history();
 245
 246         exit(0);
 247 }
 248
 249 /* Server loop callback. */
 250 static int
 251 server_loop(void)
 252 {
 253         struct client   *c;
 254         u_int            items;
 255
 256         do {
 257                 items = cmdq_next(NULL);
 258                 TAILQ_FOREACH(c, &clients, entry) {
 259                         if (c->flags & CLIENT_IDENTIFIED)
 260                                 items += cmdq_next(c);
 261                 }
 262         } while (items != 0);
 263
 264         server_client_loop();
 265
 266         if (!options_get_number(global_options, "exit-empty") && !server_exit)
 267                 return (0);
 268
 269         if (!options_get_number(global_options, "exit-unattached")) {
 270                 if (!RB_EMPTY(&sessions))
 271                         return (0);
 272         }
 273
 274         TAILQ_FOREACH(c, &clients, entry) {
 275                 if (c->session != NULL)
 276                         return (0);
 277         }
 278
 279         /*
 280          * No attached clients therefore want to exit - flush any waiting
 281          * clients but don't actually exit until they've gone.
 282          */
 283         cmd_wait_for_flush();
 284         if (!TAILQ_EMPTY(&clients))
 285                 return (0);
 286
 287         if (job_still_running())
 288                 return (0);
 289
 290         return (1);
 291 }
 292
 293 /* Exit the server by killing all clients and windows. */
 294 static void
 295 server_send_exit(void)
 296 {
 297         struct client   *c, *c1;
 298         struct session  *s, *s1;
 299
 300         cmd_wait_for_flush();
 301
 302         TAILQ_FOREACH_SAFE(c, &clients, entry, c1) {
 303                 if (c->flags & CLIENT_SUSPENDED)
 304                         server_client_lost(c);
 305                 else {
 306                         c->flags |= CLIENT_EXIT;
 307                         c->exit_type = CLIENT_EXIT_SHUTDOWN;
 308                 }
 309                 c->session = NULL;
 310         }
 311
 312         RB_FOREACH_SAFE(s, sessions, &sessions, s1)
 313                 session_destroy(s, 1, __func__);
 314 }
 315
 316 /* Update socket execute permissions based on whether sessions are attached. */
 317 void
 318 server_update_socket(void)
 319 {
 320         struct session  *s;
 321         static int       last = -1;
 322         int              n, mode;
 323         struct stat      sb;
 324
 325         n = 0;
 326         RB_FOREACH(s, sessions, &sessions) {
 327                 if (s->attached != 0) {
 328                         n++;
 329                         break;
 330                 }
 331         }
 332
 333         if (n != last) {
 334                 last = n;
 335
 336                 if (stat(socket_path, &sb) != 0)
 337                         return;
 338                 mode = sb.st_mode & ACCESSPERMS;
 339                 if (n != 0) {
 340                         if (mode & S_IRUSR)
 341                                 mode |= S_IXUSR;
 342                         if (mode & S_IRGRP)
 343                                 mode |= S_IXGRP;
 344                         if (mode & S_IROTH)
 345                                 mode |= S_IXOTH;
 346                 } else
 347                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 348                 chmod(socket_path, mode);
 349         }
 350 }
 351
 352 /* Callback for server socket. */
 353 static void
 354 server_accept(int fd, short events, __unused void *data)
 355 {
 356         struct sockaddr_storage sa;
 357         socklen_t               slen = sizeof sa;
 358         int                     newfd;
 359
 360         server_add_accept(0);
 361         if (!(events & EV_READ))
 362                 return;
 363
 364         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 365         if (newfd == -1) {
 366                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 367                         return;
 368                 if (errno == ENFILE || errno == EMFILE) {
 369                         /* Delete and don't try again for 1 second. */
 370                         server_add_accept(1);
 371                         return;
 372                 }
 373                 fatal("accept failed");
 374         }
 375         if (server_exit) {
 376                 close(newfd);
 377                 return;
 378         }
 379         server_client_create(newfd);
 380 }
 381
 382 /*
 383  * Add accept event. If timeout is nonzero, add as a timeout instead of a read
 384  * event - used to backoff when running out of file descriptors.
 385  */
 386 void
 387 server_add_accept(int timeout)
 388 {
 389         struct timeval tv = { timeout, 0 };
 390
 391         if (server_fd == -1)
 392                 return;
 393
 394         if (event_initialized(&server_ev_accept))
 395                 event_del(&server_ev_accept);
 396
 397         if (timeout == 0) {
 398                 event_set(&server_ev_accept, server_fd, EV_READ, server_accept,
 399                     NULL);
 400                 event_add(&server_ev_accept, NULL);
 401         } else {
 402                 event_set(&server_ev_accept, server_fd, EV_TIMEOUT,
 403                     server_accept, NULL);
 404                 event_add(&server_ev_accept, &tv);
 405         }
 406 }
 407
 408 /* Signal handler. */
 409 static void
 410 server_signal(int sig)
 411 {
 412         int     fd;
 413
 414         log_debug("%s: %s", __func__, strsignal(sig));
 415         switch (sig) {
 416         case SIGINT:
 417         case SIGTERM:
 418                 server_exit = 1;
 419                 server_send_exit();
 420                 break;
 421         case SIGCHLD:
 422                 server_child_signal();
 423                 break;
 424         case SIGUSR1:
 425                 event_del(&server_ev_accept);
 426                 fd = server_create_socket(server_client_flags, NULL);
 427                 if (fd != -1) {
 428                         close(server_fd);
 429                         server_fd = fd;
 430                         server_update_socket();
 431                 }
 432                 server_add_accept(0);
 433                 break;
 434         case SIGUSR2:
 435                 proc_toggle_log(server_proc);
 436                 break;
 437         }
 438 }
 439
 440 /* Handle SIGCHLD. */
 441 static void
 442 server_child_signal(void)
 443 {
 444         int      status;
 445         pid_t    pid;
 446
 447         for (;;) {
 448                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 449                 case -1:
 450                         if (errno == ECHILD)
 451                                 return;
 452                         fatal("waitpid failed");
 453                 case 0:
 454                         return;
 455                 }
 456                 if (WIFSTOPPED(status))
 457                         server_child_stopped(pid, status);
 458                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 459                         server_child_exited(pid, status);
 460         }
 461 }
 462
 463 /* Handle exited children. */
 464 static void
 465 server_child_exited(pid_t pid, int status)
 466 {
 467         struct window           *w, *w1;
 468         struct window_pane      *wp;
 469
 470         RB_FOREACH_SAFE(w, windows, &windows, w1) {
 471                 TAILQ_FOREACH(wp, &w->panes, entry) {
 472                         if (wp->pid == pid) {
 473                                 wp->status = status;
 474                                 wp->flags |= PANE_STATUSREADY;
 475
 476                                 log_debug("%%%u exited", wp->id);
 477                                 wp->flags |= PANE_EXITED;
 478
 479                                 if (window_pane_destroy_ready(wp))
 480                                         server_destroy_pane(wp, 1);
 481                                 break;
 482                         }
 483                 }
 484         }
 485         job_check_died(pid, status);
 486 }
 487
 488 /* Handle stopped children. */
 489 static void
 490 server_child_stopped(pid_t pid, int status)
 491 {
 492         struct window           *w;
 493         struct window_pane      *wp;
 494
 495         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 496                 return;
 497
 498         RB_FOREACH(w, windows, &windows) {
 499                 TAILQ_FOREACH(wp, &w->panes, entry) {
 500                         if (wp->pid == pid) {
 501                                 if (killpg(pid, SIGCONT) != 0)
 502                                         kill(pid, SIGCONT);
 503                         }
 504                 }
 505         }
 506         job_check_died(pid, status);
 507 }
 508
 509 /* Add to message log. */
 510 void
 511 server_add_message(const char *fmt, ...)
 512 {
 513         struct message_entry    *msg, *msg1;
 514         char                    *s;
 515         va_list                  ap;
 516         u_int                    limit;
 517
 518         va_start(ap, fmt);
 519         xvasprintf(&s, fmt, ap);
 520         va_end(ap);
 521
 522         log_debug("message: %s", s);
 523
 524         msg = xcalloc(1, sizeof *msg);
 525         gettimeofday(&msg->msg_time, NULL);
 526         msg->msg_num = message_next++;
 527         msg->msg = s;
 528         TAILQ_INSERT_TAIL(&message_log, msg, entry);
 529
 530         limit = options_get_number(global_options, "message-limit");
 531         TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) {
 532                 if (msg->msg_num + limit >= message_next)
 533                         break;
 534                 free(msg->msg);
 535                 TAILQ_REMOVE(&message_log, msg, entry);
 536                 free(msg);
 537         }
 538 }