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 <fcntl.h>
  28 #include <signal.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <termios.h>
  33 #include <time.h>
  34 #include <unistd.h>
  35
  36 #include "tmux.h"
  37
  38 /*
  39  * Main server functions.
  40  */
  41
  42 struct clients           clients;
  43
  44 struct tmuxproc         *server_proc;
  45 static int               server_fd = -1;
  46 static uint64_t          server_client_flags;
  47 static int               server_exit;
  48 static struct event      server_ev_accept;
  49 static struct event      server_ev_tidy;
  50
  51 struct cmd_find_state    marked_pane;
  52
  53 static u_int             message_next;
  54 struct message_list      message_log;
  55
  56 time_t                   current_time;
  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 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 #ifdef HAVE_MALLOC_TRIM
 165     malloc_trim(0);
 166 #endif
 167
 168     log_debug("%s: took %llu milliseconds", __func__,
 169         (unsigned long long)(get_timer() - t));
 170     evtimer_add(&server_ev_tidy, &tv);
 171 }
 172
 173 /* Fork new server. */
 174 int
 175 server_start(struct tmuxproc *client, int flags, struct event_base *base,
 176     int lockfd, char *lockfile)
 177 {
 178         int              fd;
 179         sigset_t         set, oldset;
 180         struct client   *c = NULL;
 181         char            *cause = NULL;
 182         struct timeval   tv = { .tv_sec = 3600 };
 183
 184         sigfillset(&set);
 185         sigprocmask(SIG_BLOCK, &set, &oldset);
 186
 187         if (~flags & CLIENT_NOFORK) {
 188                 if (proc_fork_and_daemon(&fd) != 0) {
 189                         sigprocmask(SIG_SETMASK, &oldset, NULL);
 190                         return (fd);
 191                 }
 192         }
 193         proc_clear_signals(client, 0);
 194         server_client_flags = flags;
 195
 196         if (event_reinit(base) != 0)
 197                 fatalx("event_reinit failed");
 198         server_proc = proc_start("server");
 199
 200         proc_set_signals(server_proc, server_signal);
 201         sigprocmask(SIG_SETMASK, &oldset, NULL);
 202
 203         if (log_get_level() > 1)
 204                 tty_create_log();
 205         if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec "
 206             "tty ps", NULL) != 0)
 207                 fatal("pledge failed");
 208
 209         input_key_build();
 210         RB_INIT(&windows);
 211         RB_INIT(&all_window_panes);
 212         TAILQ_INIT(&clients);
 213         RB_INIT(&sessions);
 214         key_bindings_init();
 215         TAILQ_INIT(&message_log);
 216         gettimeofday(&start_time, NULL);
 217
 218 #ifdef HAVE_SYSTEMD
 219         server_fd = systemd_create_socket(flags, &cause);
 220 #else
 221         server_fd = server_create_socket(flags, &cause);
 222 #endif
 223         if (server_fd != -1)
 224                 server_update_socket();
 225         if (~flags & CLIENT_NOFORK)
 226                 c = server_client_create(fd);
 227         else
 228                 options_set_number(global_options, "exit-empty", 0);
 229
 230         if (lockfd >= 0) {
 231                 unlink(lockfile);
 232                 free(lockfile);
 233                 close(lockfd);
 234         }
 235
 236         if (cause != NULL) {
 237                 if (c != NULL) {
 238                         c->exit_message = cause;
 239                         c->flags |= CLIENT_EXIT;
 240                 } else {
 241                         fprintf(stderr, "%s\n", cause);
 242                         exit(1);
 243                 }
 244         }
 245
 246         evtimer_set(&server_ev_tidy, server_tidy_event, NULL);
 247         evtimer_add(&server_ev_tidy, &tv);
 248
 249         server_acl_init();
 250
 251         server_add_accept(0);
 252         proc_loop(server_proc, server_loop);
 253
 254         job_kill_all();
 255         status_prompt_save_history();
 256
 257         exit(0);
 258 }
 259
 260 /* Server loop callback. */
 261 static int
 262 server_loop(void)
 263 {
 264         struct client   *c;
 265         u_int            items;
 266
 267         current_time = time(NULL);
 268
 269         do {
 270                 items = cmdq_next(NULL);
 271                 TAILQ_FOREACH(c, &clients, entry) {
 272                         if (c->flags & CLIENT_IDENTIFIED)
 273                                 items += cmdq_next(c);
 274                 }
 275         } while (items != 0);
 276
 277         server_client_loop();
 278
 279         if (!options_get_number(global_options, "exit-empty") && !server_exit)
 280                 return (0);
 281
 282         if (!options_get_number(global_options, "exit-unattached")) {
 283                 if (!RB_EMPTY(&sessions))
 284                         return (0);
 285         }
 286
 287         TAILQ_FOREACH(c, &clients, entry) {
 288                 if (c->session != NULL)
 289                         return (0);
 290         }
 291
 292         /*
 293          * No attached clients therefore want to exit - flush any waiting
 294          * clients but don't actually exit until they've gone.
 295          */
 296         cmd_wait_for_flush();
 297         if (!TAILQ_EMPTY(&clients))
 298                 return (0);
 299
 300         if (job_still_running())
 301                 return (0);
 302
 303         return (1);
 304 }
 305
 306 /* Exit the server by killing all clients and windows. */
 307 static void
 308 server_send_exit(void)
 309 {
 310         struct client   *c, *c1;
 311         struct session  *s, *s1;
 312
 313         cmd_wait_for_flush();
 314
 315         TAILQ_FOREACH_SAFE(c, &clients, entry, c1) {
 316                 if (c->flags & CLIENT_SUSPENDED)
 317                         server_client_lost(c);
 318                 else {
 319                         c->flags |= CLIENT_EXIT;
 320                         c->exit_type = CLIENT_EXIT_SHUTDOWN;
 321                 }
 322                 c->session = NULL;
 323         }
 324
 325         RB_FOREACH_SAFE(s, sessions, &sessions, s1)
 326                 session_destroy(s, 1, __func__);
 327 }
 328
 329 /* Update socket execute permissions based on whether sessions are attached. */
 330 void
 331 server_update_socket(void)
 332 {
 333         struct session  *s;
 334         static int       last = -1;
 335         int              n, mode;
 336         struct stat      sb;
 337
 338         n = 0;
 339         RB_FOREACH(s, sessions, &sessions) {
 340                 if (s->attached != 0) {
 341                         n++;
 342                         break;
 343                 }
 344         }
 345
 346         if (n != last) {
 347                 last = n;
 348
 349                 if (stat(socket_path, &sb) != 0)
 350                         return;
 351                 mode = sb.st_mode & ACCESSPERMS;
 352                 if (n != 0) {
 353                         if (mode & S_IRUSR)
 354                                 mode |= S_IXUSR;
 355                         if (mode & S_IRGRP)
 356                                 mode |= S_IXGRP;
 357                         if (mode & S_IROTH)
 358                                 mode |= S_IXOTH;
 359                 } else
 360                         mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
 361                 chmod(socket_path, mode);
 362         }
 363 }
 364
 365 /* Callback for server socket. */
 366 static void
 367 server_accept(int fd, short events, __unused void *data)
 368 {
 369         struct sockaddr_storage  sa;
 370         socklen_t                slen = sizeof sa;
 371         int                      newfd;
 372         struct client           *c;
 373
 374         server_add_accept(0);
 375         if (!(events & EV_READ))
 376                 return;
 377
 378         newfd = accept(fd, (struct sockaddr *) &sa, &slen);
 379         if (newfd == -1) {
 380                 if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
 381                         return;
 382                 if (errno == ENFILE || errno == EMFILE) {
 383                         /* Delete and don't try again for 1 second. */
 384                         server_add_accept(1);
 385                         return;
 386                 }
 387                 fatal("accept failed");
 388         }
 389
 390         if (server_exit) {
 391                 close(newfd);
 392                 return;
 393         }
 394         c = server_client_create(newfd);
 395         if (!server_acl_join(c)) {
 396                 c->exit_message = xstrdup("access not allowed");
 397                 c->flags |= CLIENT_EXIT;
 398         }
 399 }
 400
 401 /*
 402  * Add accept event. If timeout is nonzero, add as a timeout instead of a read
 403  * event - used to backoff when running out of file descriptors.
 404  */
 405 void
 406 server_add_accept(int timeout)
 407 {
 408         struct timeval tv = { timeout, 0 };
 409
 410         if (server_fd == -1)
 411                 return;
 412
 413         if (event_initialized(&server_ev_accept))
 414                 event_del(&server_ev_accept);
 415
 416         if (timeout == 0) {
 417                 event_set(&server_ev_accept, server_fd, EV_READ, server_accept,
 418                     NULL);
 419                 event_add(&server_ev_accept, NULL);
 420         } else {
 421                 event_set(&server_ev_accept, server_fd, EV_TIMEOUT,
 422                     server_accept, NULL);
 423                 event_add(&server_ev_accept, &tv);
 424         }
 425 }
 426
 427 /* Signal handler. */
 428 static void
 429 server_signal(int sig)
 430 {
 431         int     fd;
 432
 433         log_debug("%s: %s", __func__, strsignal(sig));
 434         switch (sig) {
 435         case SIGINT:
 436         case SIGTERM:
 437                 server_exit = 1;
 438                 server_send_exit();
 439                 break;
 440         case SIGCHLD:
 441                 server_child_signal();
 442                 break;
 443         case SIGUSR1:
 444                 event_del(&server_ev_accept);
 445                 fd = server_create_socket(server_client_flags, NULL);
 446                 if (fd != -1) {
 447                         close(server_fd);
 448                         server_fd = fd;
 449                         server_update_socket();
 450                 }
 451                 server_add_accept(0);
 452                 break;
 453         case SIGUSR2:
 454                 proc_toggle_log(server_proc);
 455                 break;
 456         }
 457 }
 458
 459 /* Handle SIGCHLD. */
 460 static void
 461 server_child_signal(void)
 462 {
 463         int      status;
 464         pid_t    pid;
 465
 466         for (;;) {
 467                 switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
 468                 case -1:
 469                         if (errno == ECHILD)
 470                                 return;
 471                         fatal("waitpid failed");
 472                 case 0:
 473                         return;
 474                 }
 475                 if (WIFSTOPPED(status))
 476                         server_child_stopped(pid, status);
 477                 else if (WIFEXITED(status) || WIFSIGNALED(status))
 478                         server_child_exited(pid, status);
 479         }
 480 }
 481
 482 /* Handle exited children. */
 483 static void
 484 server_child_exited(pid_t pid, int status)
 485 {
 486         struct window           *w, *w1;
 487         struct window_pane      *wp;
 488
 489         RB_FOREACH_SAFE(w, windows, &windows, w1) {
 490                 TAILQ_FOREACH(wp, &w->panes, entry) {
 491                         if (wp->pid == pid) {
 492                                 wp->status = status;
 493                                 wp->flags |= PANE_STATUSREADY;
 494
 495                                 log_debug("%%%u exited", wp->id);
 496                                 wp->flags |= PANE_EXITED;
 497
 498                                 if (window_pane_destroy_ready(wp))
 499                                         server_destroy_pane(wp, 1);
 500                                 break;
 501                         }
 502                 }
 503         }
 504         job_check_died(pid, status);
 505 }
 506
 507 /* Handle stopped children. */
 508 static void
 509 server_child_stopped(pid_t pid, int status)
 510 {
 511         struct window           *w;
 512         struct window_pane      *wp;
 513
 514         if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
 515                 return;
 516
 517         RB_FOREACH(w, windows, &windows) {
 518                 TAILQ_FOREACH(wp, &w->panes, entry) {
 519                         if (wp->pid == pid) {
 520                                 if (killpg(pid, SIGCONT) != 0)
 521                                         kill(pid, SIGCONT);
 522                         }
 523                 }
 524         }
 525         job_check_died(pid, status);
 526 }
 527
 528 /* Add to message log. */
 529 void
 530 server_add_message(const char *fmt, ...)
 531 {
 532         struct message_entry    *msg, *msg1;
 533         char                    *s;
 534         va_list                  ap;
 535         u_int                    limit;
 536
 537         va_start(ap, fmt);
 538         xvasprintf(&s, fmt, ap);
 539         va_end(ap);
 540
 541         log_debug("message: %s", s);
 542
 543         msg = xcalloc(1, sizeof *msg);
 544         gettimeofday(&msg->msg_time, NULL);
 545         msg->msg_num = message_next++;
 546         msg->msg = s;
 547         TAILQ_INSERT_TAIL(&message_log, msg, entry);
 548
 549         limit = options_get_number(global_options, "message-limit");
 550         TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) {
 551                 if (msg->msg_num + limit >= message_next)
 552                         break;
 553                 free(msg->msg);
 554                 TAILQ_REMOVE(&message_log, msg, entry);
 555                 free(msg);
 556         }
 557 }