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_add_accept(0);
 243         proc_loop(server_proc, server_loop);
 244
 245         job_kill_all();
 246         status_prompt_save_history();
 247
 248         exit(0);
 249 }
 250
 251 /* Server loop callback. */
 252 static int
 253 server_loop(void)
 254 {
 255         struct client   *c;
 256         u_int            items;
 257
 258         do {
 259                 items = cmdq_next(NULL);
 260                 TAILQ_FOREACH(c, &clients, entry) {
 261                         if (c->flags & CLIENT_IDENTIFIED)
 262                                 items += cmdq_next(c);
 263                 }
 264         } while (items != 0);
 265
 266         server_client_loop();
 267
 268         if (!options_get_number(global_options, "exit-empty") && !server_exit)
 269                 return (0);
 270
 271         if (!options_get_number(global_options, "exit-unattached")) {
 272                 if (!RB_EMPTY(&sessions))
 273                         return (0);
 274         }
 275
 276         TAILQ_FOREACH(c, &clients, entry) {
 277                 if (c->session != NULL)
 278                         return (0);
 279         }
 280
 281         /*
 282          * No attached clients therefore want to exit - flush any waiting
 283          * clients but don't actually exit until they've gone.
 284          */
 285         cmd_wait_for_flush();
 286         if (!TAILQ_EMPTY(&clients))
 287                 return (0);
 288
 289         if (job_still_running())
 290                 return (0);
 291
 292         return (1);
 293 }
 294
 295 /* Exit the server by killing all clients and windows. */
 296 static void
 297 server_send_exit(void)
 298 {
 299         struct client   *c, *c1;
 300         struct session  *s, *s1;
 301
 302         cmd_wait_for_flush();
 303
 304         TAILQ_FOREACH_SAFE(c, &clients, entry, c1) {
 305                 if (c->flags & CLIENT_SUSPENDED)
 306                         server_client_lost(c);
 307                 else {
 308                         c->flags |= CLIENT_EXIT;
 309                         c->exit_type = CLIENT_EXIT_SHUTDOWN;
 310                 }
 311                 c->session = NULL;
 312         }
 313
 314         RB_FOREACH_SAFE(s, sessions, &sessions, s1)
 315                 session_destroy(s, 1, __func__);
 316 }
 317
 318 /* Update socket execute permissions based on whether sessions are attached. */
 319 void
 320 server_update_socket(void)
 321 {
 322         struct session  *s;
 323         static int       last = -1;
 324         int              n, mode;
 325         struct stat      sb;
 326
 327         n = 0;
 328         RB_FOREACH(s, sessions, &sessions) {
 329                 if (s->attached != 0) {
 330                         n++;
 331                         break;
 332                 }
 333         }
 334
 335         if (n != last) {
 336                 last = n;
 337
 338                 if (stat(socket_path, &sb) != 0)
 339                         return;
 340                 mode = sb.st_mode & ACCESSPERMS;
 341                 if (n != 0) {
 342                         if (mode & S_IRUSR)
 343                                 mode |= S_IXUSR;
 344                         if (mode & S_IRGRP)
 345                                 mode |= S_IXGRP;
 346                         if (mode & S_IROTH)
 347                                 mode |= S_IXOTH;
 348                 } else
 349                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 350                 chmod(socket_path, mode);
 351         }
 352 }
 353
 354 /* Callback for server socket. */
 355 static void
 356 server_accept(int fd, short events, __unused void *data)
 357 {
 358         struct sockaddr_storage sa;
 359         socklen_t               slen = sizeof sa;
 360         int                     newfd;
 361
 362         server_add_accept(0);
 363         if (!(events & EV_READ))
 364                 return;
 365
 366         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 367         if (newfd == -1) {
 368                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 369                         return;
 370                 if (errno == ENFILE || errno == EMFILE) {
 371                         /* Delete and don't try again for 1 second. */
 372                         server_add_accept(1);
 373                         return;
 374                 }
 375                 fatal("accept failed");
 376         }
 377         if (server_exit) {
 378                 close(newfd);
 379                 return;
 380         }
 381         server_client_create(newfd);
 382 }
 383
 384 /*
 385  * Add accept event. If timeout is nonzero, add as a timeout instead of a read
 386  * event - used to backoff when running out of file descriptors.
 387  */
 388 void
 389 server_add_accept(int timeout)
 390 {
 391         struct timeval tv = { timeout, 0 };
 392
 393         if (server_fd == -1)
 394                 return;
 395
 396         if (event_initialized(&server_ev_accept))
 397                 event_del(&server_ev_accept);
 398
 399         if (timeout == 0) {
 400                 event_set(&server_ev_accept, server_fd, EV_READ, server_accept,
 401                     NULL);
 402                 event_add(&server_ev_accept, NULL);
 403         } else {
 404                 event_set(&server_ev_accept, server_fd, EV_TIMEOUT,
 405                     server_accept, NULL);
 406                 event_add(&server_ev_accept, &tv);
 407         }
 408 }
 409
 410 /* Signal handler. */
 411 static void
 412 server_signal(int sig)
 413 {
 414         int     fd;
 415
 416         log_debug("%s: %s", __func__, strsignal(sig));
 417         switch (sig) {
 418         case SIGINT:
 419         case SIGTERM:
 420                 server_exit = 1;
 421                 server_send_exit();
 422                 break;
 423         case SIGCHLD:
 424                 server_child_signal();
 425                 break;
 426         case SIGUSR1:
 427                 event_del(&server_ev_accept);
 428                 fd = server_create_socket(server_client_flags, NULL);
 429                 if (fd != -1) {
 430                         close(server_fd);
 431                         server_fd = fd;
 432                         server_update_socket();
 433                 }
 434                 server_add_accept(0);
 435                 break;
 436         case SIGUSR2:
 437                 proc_toggle_log(server_proc);
 438                 break;
 439         }
 440 }
 441
 442 /* Handle SIGCHLD. */
 443 static void
 444 server_child_signal(void)
 445 {
 446         int      status;
 447         pid_t    pid;
 448
 449         for (;;) {
 450                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 451                 case -1:
 452                         if (errno == ECHILD)
 453                                 return;
 454                         fatal("waitpid failed");
 455                 case 0:
 456                         return;
 457                 }
 458                 if (WIFSTOPPED(status))
 459                         server_child_stopped(pid, status);
 460                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 461                         server_child_exited(pid, status);
 462         }
 463 }
 464
 465 /* Handle exited children. */
 466 static void
 467 server_child_exited(pid_t pid, int status)
 468 {
 469         struct window           *w, *w1;
 470         struct window_pane      *wp;
 471
 472         RB_FOREACH_SAFE(w, windows, &windows, w1) {
 473                 TAILQ_FOREACH(wp, &w->panes, entry) {
 474                         if (wp->pid == pid) {
 475                                 wp->status = status;
 476                                 wp->flags |= PANE_STATUSREADY;
 477
 478                                 log_debug("%%%u exited", wp->id);
 479                                 wp->flags |= PANE_EXITED;
 480
 481                                 if (window_pane_destroy_ready(wp))
 482                                         server_destroy_pane(wp, 1);
 483                                 break;
 484                         }
 485                 }
 486         }
 487         job_check_died(pid, status);
 488 }
 489
 490 /* Handle stopped children. */
 491 static void
 492 server_child_stopped(pid_t pid, int status)
 493 {
 494         struct window           *w;
 495         struct window_pane      *wp;
 496
 497         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 498                 return;
 499
 500         RB_FOREACH(w, windows, &windows) {
 501                 TAILQ_FOREACH(wp, &w->panes, entry) {
 502                         if (wp->pid == pid) {
 503                                 if (killpg(pid, SIGCONT) != 0)
 504                                         kill(pid, SIGCONT);
 505                         }
 506                 }
 507         }
 508         job_check_died(pid, status);
 509 }
 510
 511 /* Add to message log. */
 512 void
 513 server_add_message(const char *fmt, ...)
 514 {
 515         struct message_entry    *msg, *msg1;
 516         char                    *s;
 517         va_list                  ap;
 518         u_int                    limit;
 519
 520         va_start(ap, fmt);
 521         xvasprintf(&s, fmt, ap);
 522         va_end(ap);
 523
 524         log_debug("message: %s", s);
 525
 526         msg = xcalloc(1, sizeof *msg);
 527         gettimeofday(&msg->msg_time, NULL);
 528         msg->msg_num = message_next++;
 529         msg->msg = s;
 530         TAILQ_INSERT_TAIL(&message_log, msg, entry);
 531
 532         limit = options_get_number(global_options, "message-limit");
 533         TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) {
 534                 if (msg->msg_num + limit >= message_next)
 535                         break;
 536                 free(msg->msg);
 537                 TAILQ_REMOVE(&message_log, msg, entry);
 538                 free(msg);
 539         }
 540 }