tmux.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/stat.h>
  21
  22 #include <errno.h>
  23 #include <event.h>
  24 #include <paths.h>
  25 #include <pwd.h>
  26 #include <signal.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <syslog.h>
  30 #include <unistd.h>
  31
  32 #include "tmux.h"
  33
  34 #ifdef DEBUG
  35 extern char     *malloc_options;
  36 #endif
  37
  38 char            *cfg_file;
  39 struct options   global_options;        /* server options */
  40 struct options   global_s_options;      /* session options */
  41 struct options   global_w_options;      /* window options */
  42 struct environ   global_environ;
  43
  44 int              debug_level;
  45 time_t           start_time;
  46 char            *socket_path;
  47 int              login_shell;
  48
  49 struct env_data {
  50         char    *path;
  51         pid_t    pid;
  52         u_int    idx;
  53 };
  54
  55 __dead void      usage(void);
  56 void             parse_env(struct env_data *);
  57 char            *makesockpath(const char *);
  58 __dead void      shell_exec(const char *, const char *);
  59
  60 struct imsgbuf  *main_ibuf;
  61 struct event     main_ev_sigterm;
  62 int              main_exitval;
  63
  64 void             main_set_signals(void);
  65 void             main_clear_signals(void);
  66 void             main_signal(int, short, unused void *);
  67 void             main_callback(int, short, void *);
  68 void             main_dispatch(const char *);
  69
  70 __dead void
  71 usage(void)
  72 {
  73         fprintf(stderr,
  74             "usage: %s [-28lquv] [-c shell-command] [-f file] [-L socket-name]\n"
  75             "            [-S socket-path] [command [flags]]\n",
  76             __progname);
  77         exit(1);
  78 }
  79
  80 void
  81 logfile(const char *name)
  82 {
  83         char    *path;
  84
  85         log_close();
  86         if (debug_level > 0) {
  87                 xasprintf(&path, "tmux-%s-%ld.log", name, (long) getpid());
  88                 log_open_file(debug_level, path);
  89                 xfree(path);
  90         }
  91 }
  92
  93 const char *
  94 getshell(void)
  95 {
  96         struct passwd   *pw;
  97         const char      *shell;
  98
  99         shell = getenv("SHELL");
 100         if (checkshell(shell))
 101                 return (shell);
 102
 103         pw = getpwuid(getuid());
 104         if (pw != NULL && checkshell(pw->pw_shell))
 105                 return (pw->pw_shell);
 106
 107         return (_PATH_BSHELL);
 108 }
 109
 110 int
 111 checkshell(const char *shell)
 112 {
 113         if (shell == NULL || *shell == '\0' || areshell(shell))
 114                 return (0);
 115         if (access(shell, X_OK) != 0)
 116                 return (0);
 117         return (1);
 118 }
 119
 120 int
 121 areshell(const char *shell)
 122 {
 123         const char      *progname, *ptr;
 124
 125         if ((ptr = strrchr(shell, '/')) != NULL)
 126                 ptr++;
 127         else
 128                 ptr = shell;
 129         progname = __progname;
 130         if (*progname == '-')
 131                 progname++;
 132         if (strcmp(ptr, progname) == 0)
 133                 return (1);
 134         return (0);
 135 }
 136
 137 void
 138 parse_env(struct env_data *data)
 139 {
 140         char            *env, *path_pid, *pid_idx, buf[256];
 141         size_t           len;
 142         const char      *errstr;
 143         long long        ll;
 144
 145         data->pid = -1;
 146         if ((env = getenv("TMUX")) == NULL)
 147                 return;
 148
 149         if ((path_pid = strchr(env, ',')) == NULL || path_pid == env)
 150                 return;
 151         if ((pid_idx = strchr(path_pid + 1, ',')) == NULL)
 152                 return;
 153         if ((pid_idx == path_pid + 1 || pid_idx[1] == '\0'))
 154                 return;
 155
 156         /* path */
 157         len = path_pid - env;
 158         data->path = xmalloc (len + 1);
 159         memcpy(data->path, env, len);
 160         data->path[len] = '\0';
 161
 162         /* pid */
 163         len = pid_idx - path_pid - 1;
 164         if (len > (sizeof buf) - 1)
 165                 return;
 166         memcpy(buf, path_pid + 1, len);
 167         buf[len] = '\0';
 168
 169         ll = strtonum(buf, 0, LONG_MAX, &errstr);
 170         if (errstr != NULL)
 171                 return;
 172         data->pid = ll;
 173
 174         /* idx */
 175         ll = strtonum(pid_idx+1, 0, UINT_MAX, &errstr);
 176         if (errstr != NULL)
 177                 return;
 178         data->idx = ll;
 179 }
 180
 181 char *
 182 makesockpath(const char *label)
 183 {
 184         char            base[MAXPATHLEN], *path;
 185         struct stat     sb;
 186         u_int           uid;
 187
 188         uid = getuid();
 189         xsnprintf(base, MAXPATHLEN, "%s/tmux-%d", _PATH_TMP, uid);
 190
 191         if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST)
 192                 return (NULL);
 193
 194         if (lstat(base, &sb) != 0)
 195                 return (NULL);
 196         if (!S_ISDIR(sb.st_mode)) {
 197                 errno = ENOTDIR;
 198                 return (NULL);
 199         }
 200         if (sb.st_uid != uid || (sb.st_mode & (S_IRWXG|S_IRWXO)) != 0) {
 201                 errno = EACCES;
 202                 return (NULL);
 203         }
 204
 205         xasprintf(&path, "%s/%s", base, label);
 206         return (path);
 207 }
 208
 209 __dead void
 210 shell_exec(const char *shell, const char *shellcmd)
 211 {
 212         const char      *shellname, *ptr;
 213         char            *argv0;
 214
 215         ptr = strrchr(shell, '/');
 216         if (ptr != NULL && *(ptr + 1) != '\0')
 217                 shellname = ptr + 1;
 218         else
 219                 shellname = shell;
 220         if (login_shell)
 221                 xasprintf(&argv0, "-%s", shellname);
 222         else
 223                 xasprintf(&argv0, "%s", shellname);
 224         setenv("SHELL", shell, 1);
 225
 226         execl(shell, argv0, "-c", shellcmd, (char *) NULL);
 227         fatal("execl failed");
 228 }
 229
 230 int
 231 main(int argc, char **argv)
 232 {
 233         struct cmd_list         *cmdlist;
 234         struct cmd              *cmd;
 235         enum msgtype             msg;
 236         struct passwd           *pw;
 237         struct options          *oo, *so, *wo;
 238         struct keylist          *keylist;
 239         struct env_data          envdata;
 240         struct msg_command_data  cmddata;
 241         struct sigaction         sigact;
 242         char                    *s, *shellcmd, *path, *label, *home, *cause;
 243         char                     cwd[MAXPATHLEN], **var;
 244         void                    *buf;
 245         size_t                   len;
 246         int                      opt, flags, quiet = 0, cmdflags = 0;
 247         short                    events;
 248
 249 #ifdef DEBUG
 250         malloc_options = (char *) "AFGJPX";
 251 #endif
 252
 253         flags = 0;
 254         shellcmd = label = path = NULL;
 255         envdata.path = NULL;
 256         login_shell = (**argv == '-');
 257         while ((opt = getopt(argc, argv, "28c:df:lL:qS:uUv")) != -1) {
 258                 switch (opt) {
 259                 case '2':
 260                         flags |= IDENTIFY_256COLOURS;
 261                         flags &= ~IDENTIFY_88COLOURS;
 262                         break;
 263                 case '8':
 264                         flags |= IDENTIFY_88COLOURS;
 265                         flags &= ~IDENTIFY_256COLOURS;
 266                         break;
 267                 case 'c':
 268                         if (shellcmd != NULL)
 269                                 xfree(shellcmd);
 270                         shellcmd = xstrdup(optarg);
 271                         break;
 272                 case 'f':
 273                         if (cfg_file != NULL)
 274                                 xfree(cfg_file);
 275                         cfg_file = xstrdup(optarg);
 276                         break;
 277                 case 'l':
 278                         login_shell = 1;
 279                         break;
 280                 case 'L':
 281                         if (label != NULL)
 282                                 xfree(label);
 283                         label = xstrdup(optarg);
 284                         break;
 285                 case 'q':
 286                         quiet = 1;
 287                         break;
 288                 case 'S':
 289                         if (path != NULL)
 290                                 xfree(path);
 291                         path = xstrdup(optarg);
 292                         break;
 293                 case 'u':
 294                         flags |= IDENTIFY_UTF8;
 295                         break;
 296                 case 'v':
 297                         debug_level++;
 298                         break;
 299                 default:
 300                         usage();
 301                 }
 302         }
 303         argc -= optind;
 304         argv += optind;
 305
 306         if (shellcmd != NULL && argc != 0)
 307                 usage();
 308
 309         log_open_tty(debug_level);
 310
 311         if (!(flags & IDENTIFY_UTF8)) {
 312                 /*
 313                  * If the user has set whichever of LC_ALL, LC_CTYPE or LANG
 314                  * exist (in that order) to contain UTF-8, it is a safe
 315                  * assumption that either they are using a UTF-8 terminal, or
 316                  * if not they know that output from UTF-8-capable programs may
 317                  * be wrong.
 318                  */
 319                 if ((s = getenv("LC_ALL")) == NULL) {
 320                         if ((s = getenv("LC_CTYPE")) == NULL)
 321                                 s = getenv("LANG");
 322                 }
 323                 if (s != NULL && (strcasestr(s, "UTF-8") != NULL ||
 324                     strcasestr(s, "UTF8") != NULL))
 325                         flags |= IDENTIFY_UTF8;
 326         }
 327
 328         environ_init(&global_environ);
 329         for (var = environ; *var != NULL; var++)
 330                 environ_put(&global_environ, *var);
 331
 332         options_init(&global_options, NULL);
 333         oo = &global_options;
 334         options_set_number(oo, "quiet", quiet);
 335         options_set_number(oo, "escape-time", 500);
 336
 337         options_init(&global_s_options, NULL);
 338         so = &global_s_options;
 339         options_set_number(so, "base-index", 0);
 340         options_set_number(so, "bell-action", BELL_ANY);
 341         options_set_number(so, "buffer-limit", 9);
 342         options_set_string(so, "default-command", "%s", "");
 343         options_set_string(so, "default-shell", "%s", getshell());
 344         options_set_string(so, "default-terminal", "screen");
 345         options_set_number(so, "display-panes-colour", 4);
 346         options_set_number(so, "display-panes-active-colour", 1);
 347         options_set_number(so, "display-panes-time", 1000);
 348         options_set_number(so, "display-time", 750);
 349         options_set_number(so, "history-limit", 2000);
 350         options_set_number(so, "lock-after-time", 0);
 351         options_set_string(so, "lock-command", "lock -np");
 352         options_set_number(so, "lock-server", 1);
 353         options_set_number(so, "message-attr", 0);
 354         options_set_number(so, "message-bg", 3);
 355         options_set_number(so, "message-fg", 0);
 356         options_set_number(so, "message-limit", 20);
 357         options_set_number(so, "mouse-select-pane", 0);
 358         options_set_number(so, "pane-active-border-bg", 8);
 359         options_set_number(so, "pane-active-border-fg", 2);
 360         options_set_number(so, "pane-border-bg", 8);
 361         options_set_number(so, "pane-border-fg", 8);
 362         options_set_number(so, "repeat-time", 500);
 363         options_set_number(so, "set-remain-on-exit", 0);
 364         options_set_number(so, "set-titles", 0);
 365         options_set_string(so, "set-titles-string", "#S:#I:#W - \"#T\"");
 366         options_set_number(so, "status", 1);
 367         options_set_number(so, "status-attr", 0);
 368         options_set_number(so, "status-bg", 2);
 369         options_set_number(so, "status-fg", 0);
 370         options_set_number(so, "status-interval", 15);
 371         options_set_number(so, "status-justify", 0);
 372         options_set_number(so, "status-keys", MODEKEY_EMACS);
 373         options_set_string(so, "status-left", "[#S]");
 374         options_set_number(so, "status-left-attr", 0);
 375         options_set_number(so, "status-left-bg", 8);
 376         options_set_number(so, "status-left-fg", 8);
 377         options_set_number(so, "status-left-length", 10);
 378         options_set_string(so, "status-right", "\"#22T\" %%H:%%M %%d-%%b-%%y");
 379         options_set_number(so, "status-right-attr", 0);
 380         options_set_number(so, "status-right-bg", 8);
 381         options_set_number(so, "status-right-fg", 8);
 382         options_set_number(so, "status-right-length", 40);
 383         options_set_string(so, "terminal-overrides",
 384             "*88col*:colors=88,*256col*:colors=256");
 385         options_set_string(so, "update-environment", "DISPLAY "
 386             "WINDOWID SSH_ASKPASS SSH_AUTH_SOCK SSH_AGENT_PID SSH_CONNECTION");
 387         options_set_number(so, "visual-activity", 0);
 388         options_set_number(so, "visual-bell", 0);
 389         options_set_number(so, "visual-content", 0);
 390
 391         keylist = xmalloc(sizeof *keylist);
 392         ARRAY_INIT(keylist);
 393         ARRAY_ADD(keylist, '\002');
 394         options_set_data(so, "prefix", keylist, xfree);
 395
 396         options_init(&global_w_options, NULL);
 397         wo = &global_w_options;
 398         options_set_number(wo, "aggressive-resize", 0);
 399         options_set_number(wo, "alternate-screen", 1);
 400         options_set_number(wo, "automatic-rename", 1);
 401         options_set_number(wo, "clock-mode-colour", 4);
 402         options_set_number(wo, "clock-mode-style", 1);
 403         options_set_number(wo, "force-height", 0);
 404         options_set_number(wo, "force-width", 0);
 405         options_set_number(wo, "main-pane-height", 24);
 406         options_set_number(wo, "main-pane-width", 81);
 407         options_set_number(wo, "mode-attr", 0);
 408         options_set_number(wo, "mode-bg", 3);
 409         options_set_number(wo, "mode-fg", 0);
 410         options_set_number(wo, "mode-keys", MODEKEY_EMACS);
 411         options_set_number(wo, "mode-mouse", 0);
 412         options_set_number(wo, "monitor-activity", 0);
 413         options_set_string(wo, "monitor-content", "%s", "");
 414         options_set_number(wo, "window-status-attr", 0);
 415         options_set_number(wo, "window-status-bg", 8);
 416         options_set_number(wo, "window-status-current-attr", 0);
 417         options_set_number(wo, "window-status-current-bg", 8);
 418         options_set_number(wo, "window-status-current-fg", 8);
 419         options_set_number(wo, "window-status-fg", 8);
 420         options_set_string(wo, "window-status-format", "#I:#W#F");
 421         options_set_string(wo, "window-status-current-format", "#I:#W#F");
 422         options_set_string(wo, "word-separators", " -_@");
 423         options_set_number(wo, "xterm-keys", 0);
 424         options_set_number(wo, "remain-on-exit", 0);
 425         options_set_number(wo, "synchronize-panes", 0);
 426
 427         if (flags & IDENTIFY_UTF8) {
 428                 options_set_number(so, "status-utf8", 1);
 429                 options_set_number(wo, "utf8", 1);
 430         } else {
 431                 options_set_number(so, "status-utf8", 0);
 432                 options_set_number(wo, "utf8", 0);
 433         }
 434
 435         if (getcwd(cwd, sizeof cwd) == NULL) {
 436                 pw = getpwuid(getuid());
 437                 if (pw->pw_dir != NULL && *pw->pw_dir != '\0')
 438                         strlcpy(cwd, pw->pw_dir, sizeof cwd);
 439                 else
 440                         strlcpy(cwd, "/", sizeof cwd);
 441         }
 442         options_set_string(so, "default-path", "%s", cwd);
 443
 444         if (cfg_file == NULL) {
 445                 home = getenv("HOME");
 446                 if (home == NULL || *home == '\0') {
 447                         pw = getpwuid(getuid());
 448                         if (pw != NULL)
 449                                 home = pw->pw_dir;
 450                 }
 451                 xasprintf(&cfg_file, "%s/%s", home, DEFAULT_CFG);
 452                 if (access(cfg_file, R_OK) != 0 && errno == ENOENT) {
 453                         xfree(cfg_file);
 454                         cfg_file = NULL;
 455                 }
 456         }
 457
 458         /*
 459          * Figure out the socket path. If specified on the command-line with
 460          * -S or -L, use it, otherwise try $TMUX or assume -L default.
 461          */
 462         parse_env(&envdata);
 463         if (path == NULL) {
 464                 /* No -L. Try $TMUX, or default. */
 465                 if (label == NULL) {
 466                         path = envdata.path;
 467                         if (path == NULL)
 468                                 label = xstrdup("default");
 469                 }
 470
 471                 /* -L or default set. */
 472                 if (label != NULL) {
 473                         if ((path = makesockpath(label)) == NULL) {
 474                                 log_warn("can't create socket");
 475                                 exit(1);
 476                         }
 477                 }
 478         }
 479         if (label != NULL)
 480                 xfree(label);
 481
 482         if (shellcmd != NULL) {
 483                 msg = MSG_SHELL;
 484                 buf = NULL;
 485                 len = 0;
 486         } else {
 487                 cmddata.pid = envdata.pid;
 488                 cmddata.idx = envdata.idx;
 489
 490                 /* Prepare command for server. */
 491                 cmddata.argc = argc;
 492                 if (cmd_pack_argv(
 493                     argc, argv, cmddata.argv, sizeof cmddata.argv) != 0) {
 494                         log_warnx("command too long");
 495                         exit(1);
 496                 }
 497
 498                 msg = MSG_COMMAND;
 499                 buf = &cmddata;
 500                 len = sizeof cmddata;
 501         }
 502
 503         if (shellcmd != NULL)
 504                 cmdflags |= CMD_STARTSERVER;
 505         else if (argc == 0)     /* new-session is the default */
 506                 cmdflags |= CMD_STARTSERVER|CMD_SENDENVIRON|CMD_CANTNEST;
 507         else {
 508                 /*
 509                  * It sucks parsing the command string twice (in client and
 510                  * later in server) but it is necessary to get the start server
 511                  * flag.
 512                  */
 513                 if ((cmdlist = cmd_list_parse(argc, argv, &cause)) == NULL) {
 514                         log_warnx("%s", cause);
 515                         exit(1);
 516                 }
 517                 cmdflags &= ~CMD_STARTSERVER;
 518                 TAILQ_FOREACH(cmd, cmdlist, qentry) {
 519                         if (cmd->entry->flags & CMD_STARTSERVER)
 520                                 cmdflags |= CMD_STARTSERVER;
 521                         if (cmd->entry->flags & CMD_SENDENVIRON)
 522                                 cmdflags |= CMD_SENDENVIRON;
 523                         if (cmd->entry->flags & CMD_CANTNEST)
 524                                 cmdflags |= CMD_CANTNEST;
 525                 }
 526                 cmd_list_free(cmdlist);
 527         }
 528
 529         /*
 530          * Check if this could be a nested session, if the command can't nest:
 531          * if the socket path matches $TMUX, this is probably the same server.
 532          */
 533         if (shellcmd == NULL && envdata.path != NULL &&
 534             cmdflags & CMD_CANTNEST &&
 535             (path == envdata.path || strcmp(path, envdata.path) == 0)) {
 536                 log_warnx("sessions should be nested with care. "
 537                     "unset $TMUX to force.");
 538                 exit(1);
 539         }
 540
 541         /* Catch SIGCHLD to avoid a zombie when starting the server. */
 542         memset(&sigact, 0, sizeof sigact);
 543         sigemptyset(&sigact.sa_mask);
 544         sigact.sa_handler = SIG_IGN;
 545         if (sigaction(SIGCHLD, &sigact, NULL) != 0)
 546                 fatal("sigaction failed");
 547
 548         /* Initialise the client socket/start the server. */
 549         if ((main_ibuf = client_init(path, cmdflags, flags)) == NULL)
 550                 exit(1);
 551         xfree(path);
 552
 553         event_init();
 554
 555         imsg_compose(main_ibuf, msg, PROTOCOL_VERSION, -1, -1, buf, len);
 556
 557         main_set_signals();
 558
 559         events = EV_READ;
 560         if (main_ibuf->w.queued > 0)
 561                 events |= EV_WRITE;
 562         event_once(main_ibuf->fd, events, main_callback, shellcmd, NULL);
 563
 564         main_exitval = 0;
 565         event_dispatch();
 566
 567         main_clear_signals();
 568
 569         client_main();  /* doesn't return */
 570 }
 571
 572 void
 573 main_set_signals(void)
 574 {
 575         struct sigaction        sigact;
 576
 577         memset(&sigact, 0, sizeof sigact);
 578         sigemptyset(&sigact.sa_mask);
 579         sigact.sa_flags = SA_RESTART;
 580         sigact.sa_handler = SIG_IGN;
 581         if (sigaction(SIGINT, &sigact, NULL) != 0)
 582                 fatal("sigaction failed");
 583         if (sigaction(SIGPIPE, &sigact, NULL) != 0)
 584                 fatal("sigaction failed");
 585         if (sigaction(SIGUSR1, &sigact, NULL) != 0)
 586                 fatal("sigaction failed");
 587         if (sigaction(SIGUSR2, &sigact, NULL) != 0)
 588                 fatal("sigaction failed");
 589         if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 590                 fatal("sigaction failed");
 591
 592         signal_set(&main_ev_sigterm, SIGTERM, main_signal, NULL);
 593         signal_add(&main_ev_sigterm, NULL);
 594 }
 595
 596 void
 597 main_clear_signals(void)
 598 {
 599         struct sigaction        sigact;
 600
 601         memset(&sigact, 0, sizeof sigact);
 602         sigemptyset(&sigact.sa_mask);
 603         sigact.sa_flags = SA_RESTART;
 604         sigact.sa_handler = SIG_DFL;
 605         if (sigaction(SIGINT, &sigact, NULL) != 0)
 606                 fatal("sigaction failed");
 607         if (sigaction(SIGPIPE, &sigact, NULL) != 0)
 608                 fatal("sigaction failed");
 609         if (sigaction(SIGUSR1, &sigact, NULL) != 0)
 610                 fatal("sigaction failed");
 611         if (sigaction(SIGUSR2, &sigact, NULL) != 0)
 612                 fatal("sigaction failed");
 613         if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 614                 fatal("sigaction failed");
 615
 616         event_del(&main_ev_sigterm);
 617 }
 618
 619 /* ARGSUSED */
 620 void
 621 main_signal(int sig, unused short events, unused void *data)
 622 {
 623         switch (sig) {
 624         case SIGTERM:
 625                 exit(1);
 626         }
 627 }
 628
 629 /* ARGSUSED */
 630 void
 631 main_callback(unused int fd, short events, void *data)
 632 {
 633         char    *shellcmd = data;
 634
 635         if (events & EV_READ)
 636                 main_dispatch(shellcmd);
 637
 638         if (events & EV_WRITE) {
 639                 if (msgbuf_write(&main_ibuf->w) < 0)
 640                         fatalx("msgbuf_write failed");
 641         }
 642
 643         events = EV_READ;
 644         if (main_ibuf->w.queued > 0)
 645                 events |= EV_WRITE;
 646         event_once(main_ibuf->fd, events, main_callback, shellcmd, NULL);
 647 }
 648
 649 void
 650 main_dispatch(const char *shellcmd)
 651 {
 652         struct imsg             imsg;
 653         ssize_t                 n, datalen;
 654         struct msg_print_data   printdata;
 655         struct msg_shell_data   shelldata;
 656
 657         if ((n = imsg_read(main_ibuf)) == -1 || n == 0)
 658                 fatalx("imsg_read failed");
 659
 660         for (;;) {
 661                 if ((n = imsg_get(main_ibuf, &imsg)) == -1)
 662                         fatalx("imsg_get failed");
 663                 if (n == 0)
 664                         return;
 665                 datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
 666
 667                 switch (imsg.hdr.type) {
 668                 case MSG_EXIT:
 669                 case MSG_SHUTDOWN:
 670                         if (datalen != 0)
 671                                 fatalx("bad MSG_EXIT size");
 672
 673                         exit(main_exitval);
 674                 case MSG_ERROR:
 675                 case MSG_PRINT:
 676                         if (datalen != sizeof printdata)
 677                                 fatalx("bad MSG_PRINT size");
 678                         memcpy(&printdata, imsg.data, sizeof printdata);
 679                         printdata.msg[(sizeof printdata.msg) - 1] = '\0';
 680
 681                         log_info("%s", printdata.msg);
 682                         if (imsg.hdr.type == MSG_ERROR)
 683                                 main_exitval = 1;
 684                         break;
 685                 case MSG_READY:
 686                         if (datalen != 0)
 687                                 fatalx("bad MSG_READY size");
 688
 689                         event_loopexit(NULL);   /* move to client_main() */
 690                         break;
 691                 case MSG_VERSION:
 692                         if (datalen != 0)
 693                                 fatalx("bad MSG_VERSION size");
 694
 695                         log_warnx("protocol version mismatch (client %u, "
 696                             "server %u)", PROTOCOL_VERSION, imsg.hdr.peerid);
 697                         exit(1);
 698                 case MSG_SHELL:
 699                         if (datalen != sizeof shelldata)
 700                                 fatalx("bad MSG_SHELL size");
 701                         memcpy(&shelldata, imsg.data, sizeof shelldata);
 702                         shelldata.shell[(sizeof shelldata.shell) - 1] = '\0';
 703
 704                         main_clear_signals();
 705
 706                         shell_exec(shelldata.shell, shellcmd);
 707                 default:
 708                         fatalx("unexpected message");
 709                 }
 710
 711                 imsg_free(&imsg);
 712         }
 713 }