root/src/main.c

/*   */

DEFINITIONS

1. OS_Setup
2. sigchld_handler_no_subshell
3. init_sigchld
4. check_sid
5. main

   1 /*
   2    Main program for the Midnight Commander
   3 
   4    Copyright (C) 1994-2026
   5    Free Software Foundation, Inc.
   6 
   7    Written by:
   8    Miguel de Icaza, 1994, 1995, 1996, 1997
   9    Janne Kukonlehto, 1994, 1995
  10    Norbert Warmuth, 1997
  11 
  12    This file is part of the Midnight Commander.
  13 
  14    The Midnight Commander is free software: you can redistribute it
  15    and/or modify it under the terms of the GNU General Public License as
  16    published by the Free Software Foundation, either version 3 of the License,
  17    or (at your option) any later version.
  18 
  19    The Midnight Commander is distributed in the hope that it will be useful,
  20    but WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22    GNU General Public License for more details.
  23 
  24    You should have received a copy of the GNU General Public License
  25    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  26  */
  27 
  28 /** \file main.c
  29  *  \brief Source: this is a main module
  30  */
  31 
  32 #include <config.h>
  33 
  34 #include <locale.h>
  35 #include <pwd.h>  // for username in xterm title
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <sys/types.h>
  40 #include <sys/wait.h>
  41 #include <signal.h>
  42 #include <unistd.h>  // getsid()
  43 
  44 #include "lib/global.h"
  45 
  46 #include "lib/event.h"
  47 #include "lib/tty/tty.h"
  48 #include "lib/tty/key.h"    // For init_key()
  49 #include "lib/tty/mouse.h"  // init_mouse()
  50 #include "lib/skin.h"
  51 #include "lib/filehighlight.h"
  52 #include "lib/fileloc.h"
  53 #include "lib/strutil.h"
  54 #include "lib/util.h"
  55 #include "lib/vfs/vfs.h"  // vfs_init(), vfs_shut()
  56 
  57 #include "filemanager/filemanager.h"
  58 #include "filemanager/treestore.h"  // tree_store_save
  59 #include "filemanager/layout.h"
  60 #include "filemanager/ext.h"      // flush_extension_file()
  61 #include "filemanager/command.h"  // cmdline
  62 #include "filemanager/panel.h"    // panalized_panel
  63 
  64 #ifdef USE_INTERNAL_EDIT
  65 #include "editor/edit.h"  // edit_arg_free()
  66 #endif
  67 
  68 #include "vfs/plugins_init.h"
  69 
  70 #include "events_init.h"
  71 #include "args.h"
  72 #ifdef ENABLE_SUBSHELL
  73 #include "subshell/subshell.h"
  74 #endif
  75 #include "keymap.h"
  76 #include "setup.h"  // load_setup()
  77 
  78 #include "lib/charsets.h"
  79 #include "selcodepage.h"
  80 
  81 #include "consaver/cons.saver.h"  // cons_saver_pid
  82 
  83 /*** global variables ****************************************************************************/
  84 
  85 /*** file scope macro definitions ****************************************************************/
  86 
  87 /*** file scope type declarations ****************************************************************/
  88 
  89 /*** forward declarations (file scope functions) *************************************************/
  90 
  91 /*** file scope variables ************************************************************************/
  92 
  93 /* --------------------------------------------------------------------------------------------- */
  94 /*** file scope functions ************************************************************************/
  95 /* --------------------------------------------------------------------------------------------- */
  96 
  97 /** POSIX version.  The only version we support.  */
  98 static void
  99 OS_Setup (void)
     /*   */
 100 {
 101     mc_shell_init ();
 102 
 103     // This is the directory, where MC was installed, on Unix this is DATADIR
 104     // and can be overridden by the MC_DATADIR environment variable
 105     const char *datadir_env = g_getenv ("MC_DATADIR");
 106 
 107     if (datadir_env != NULL)
 108         mc_global.sysconfig_dir = g_strdup (datadir_env);
 109     else
 110         mc_global.sysconfig_dir = g_strdup (SYSCONFDIR);
 111 
 112     mc_global.share_data_dir = g_strdup (DATADIR);
 113 }
 114 
 115 /* --------------------------------------------------------------------------------------------- */
 116 
 117 static void
 118 sigchld_handler_no_subshell (int sig)
     /*   */
 119 {
 120 #ifdef __linux__
 121     int pid, status;
 122 
 123     if (mc_global.tty.console_flag == '\0')
 124         return;
 125 
 126     /* COMMENT: if it were true that after the call to handle_console(..INIT)
 127        the value of mc_global.tty.console_flag never changed, we could simply not install
 128        this handler at all if (!mc_global.tty.console_flag && !mc_global.tty.use_subshell). */
 129 
 130     /* That comment is no longer true.  We need to wait() on a sigchld
 131        handler (that's at least what the tarfs code expects currently). */
 132 
 133     pid = waitpid (cons_saver_pid, &status, WUNTRACED | WNOHANG);
 134 
 135     if (pid == cons_saver_pid)
 136     {
 137         if (WIFSTOPPED (status))
 138         {
 139             // Someone has stopped cons.saver - restart it
 140             kill (pid, SIGCONT);
 141         }
 142         else
 143         {
 144             // cons.saver has died - disable console saving
 145             handle_console (CONSOLE_DONE);
 146             mc_global.tty.console_flag = '\0';
 147         }
 148     }
 149     // If we got here, some other child exited; ignore it
 150 #endif
 151 
 152     (void) sig;
 153 }
 154 
 155 /* --------------------------------------------------------------------------------------------- */
 156 
 157 static void
 158 init_sigchld (void)
     /*   */
 159 {
 160     struct sigaction sigchld_action;
 161 
 162     memset (&sigchld_action, 0, sizeof (sigchld_action));
 163     sigchld_action.sa_handler =
 164 #ifdef ENABLE_SUBSHELL
 165         mc_global.tty.use_subshell ? sigchld_handler :
 166 #endif
 167                                    sigchld_handler_no_subshell;
 168 
 169     sigemptyset (&sigchld_action.sa_mask);
 170 
 171 #ifdef SA_RESTART
 172     sigchld_action.sa_flags = SA_RESTART;
 173 #endif
 174 
 175     if (my_sigaction (SIGCHLD, &sigchld_action, NULL) == -1)
 176     {
 177 #ifdef ENABLE_SUBSHELL
 178         /*
 179          * This may happen on QNX Neutrino 6, where SA_RESTART
 180          * is defined but not implemented.  Fallback to no subshell.
 181          */
 182         mc_global.tty.use_subshell = FALSE;
 183 #endif
 184     }
 185 }
 186 
 187 /* --------------------------------------------------------------------------------------------- */
 188 /**
 189  * Check MC_SID to prevent running one mc from another.
 190  *
 191  * @return TRUE if no parent mc in our session was found, FALSE otherwise.
 192  */
 193 
 194 static gboolean
 195 check_sid (void)
     /*   */
 196 {
 197     pid_t my_sid, old_sid;
 198     const char *sid_str;
 199 
 200     sid_str = getenv ("MC_SID");
 201     if (sid_str == NULL)
 202         return TRUE;
 203 
 204     old_sid = (pid_t) strtol (sid_str, NULL, 0);
 205     if (old_sid == 0)
 206         return TRUE;
 207 
 208     my_sid = getsid (0);
 209     if (my_sid == -1)
 210         return TRUE;
 211 
 212     // The parent mc is in a different session, it's OK
 213     return (old_sid != my_sid);
 214 }
 215 
 216 /* --------------------------------------------------------------------------------------------- */
 217 /*** public functions ****************************************************************************/
 218 /* --------------------------------------------------------------------------------------------- */
 219 
 220 int
 221 main (int argc, char *argv[])
     /*   */
 222 {
 223     GError *mcerror = NULL;
 224     int exit_code = EXIT_FAILURE;
 225     vfs_path_t *tmp_vpath = NULL;
 226 
 227     mc_global.run_from_parent_mc = !check_sid ();
 228 
 229     // We had LC_CTYPE before, LC_ALL includs LC_TYPE as well
 230 #ifdef HAVE_SETLOCALE
 231     (void) setlocale (LC_ALL, "");
 232 #endif
 233     (void) bindtextdomain (PACKAGE, LOCALEDIR);
 234     (void) textdomain (PACKAGE);
 235 
 236     // do this before args parsing
 237     str_init_strings (NULL);
 238 
 239     mc_setup_run_mode (argv);  // are we mc? editor? viewer? etc...
 240 
 241     if (!mc_args_parse (&argc, &argv, "mc", &mcerror))
 242     {
 243     startup_exit_falure:
 244         fprintf (stderr, _ ("Failed to run:\n%s\n"), mcerror->message);
 245         g_error_free (mcerror);
 246     startup_exit_ok:
 247         mc_shell_deinit ();
 248         str_uninit_strings ();
 249         return exit_code;
 250     }
 251 
 252     /* check terminal type
 253      * $TERM must be set and not empty
 254      * mc_global.tty.xterm_flag is used in init_key() and tty_init()
 255      * Do this after mc_args_parse() where mc_args__force_xterm is set up.
 256      */
 257     mc_global.tty.xterm_flag = tty_check_xterm_compat (mc_args__force_xterm);
 258 
 259     // do this before mc_args_show_info () to view paths in the --datadir-info output
 260     OS_Setup ();
 261 
 262     if (!g_path_is_absolute (mc_config_get_home_dir ()))
 263     {
 264         mc_propagate_error (&mcerror, 0, "%s: %s", _ ("Home directory path is not absolute"),
 265                             mc_config_get_home_dir ());
 266         mc_event_deinit (NULL);
 267         goto startup_exit_falure;
 268     }
 269 
 270     if (!mc_args_show_info ())
 271     {
 272         exit_code = EXIT_SUCCESS;
 273         goto startup_exit_ok;
 274     }
 275 
 276     if (!events_init (&mcerror))
 277         goto startup_exit_falure;
 278 
 279     mc_config_init_config_paths (&mcerror);
 280     if (mcerror != NULL)
 281     {
 282         mc_event_deinit (NULL);
 283         goto startup_exit_falure;
 284     }
 285 
 286     vfs_init ();
 287     vfs_plugins_init ();
 288 
 289     load_setup ();
 290 
 291     // Must be done after load_setup because depends on mc_global.vfs.cd_symlinks
 292     vfs_setup_work_dir ();
 293 
 294     // Set up temporary directory after VFS initialization
 295     const char *tmpdir = mc_tmpdir ();
 296 
 297     tmp_vpath = vfs_path_from_str (tmpdir);
 298 
 299     /* do this after vfs initialization and vfs working directory setup
 300        due to mc_setctl() and mcedit_arg_vpath_new() calls in mc_setup_by_args() */
 301     if (!mc_setup_by_args (argc, argv, &mcerror))
 302     {
 303         /* At exit, do this before vfs_shut():
 304            normally, temporary directory should be empty */
 305         vfs_expire (TRUE);
 306         (void) mc_rmdir (tmp_vpath);
 307         vfs_path_free (tmp_vpath, TRUE);
 308 
 309         vfs_shut ();
 310         done_setup ();
 311         g_free (saved_other_dir);
 312         mc_event_deinit (NULL);
 313         goto startup_exit_falure;
 314     }
 315 
 316     /* Resolve the other_dir panel option.
 317      * 1. Must be done after vfs_setup_work_dir().
 318      * 2. Must be done after mc_setup_by_args() because of mc_run_mode.
 319      */
 320     if (mc_global.mc_run_mode == MC_RUN_FULL)
 321     {
 322         char *buffer;
 323         vfs_path_t *vpath;
 324 
 325         buffer = mc_config_get_string (mc_global.panels_config, "Dirs", "other_dir", ".");
 326         vpath = vfs_path_from_str (buffer);
 327         if (vfs_file_is_local (vpath))
 328             saved_other_dir = buffer;
 329         else
 330             g_free (buffer);
 331         vfs_path_free (vpath, TRUE);
 332     }
 333 
 334     /* NOTE: This has to be called before tty_init or whatever routine
 335        calls any define_sequence */
 336     init_key ();
 337 
 338     // Must be done before installing the SIGCHLD handler [[FIXME]]
 339     handle_console (CONSOLE_INIT);
 340 
 341 #ifdef ENABLE_SUBSHELL
 342     // Disallow subshell when invoked as standalone viewer or editor from running mc
 343     if (mc_global.mc_run_mode != MC_RUN_FULL && mc_global.run_from_parent_mc)
 344         mc_global.tty.use_subshell = FALSE;
 345 
 346     if (mc_global.tty.use_subshell)
 347         subshell_get_console_attributes ();
 348 #endif
 349 
 350     // Install the SIGCHLD handler; must be done before init_subshell()
 351     init_sigchld ();
 352 
 353     // We need this, since ncurses endwin () doesn't restore the signals
 354     save_stop_handler ();
 355 
 356     // Must be done before init_subshell, to set up the terminal size:
 357     // FIXME: Should be removed and LINES and COLS computed on subshell
 358     tty_init (!mc_args__nomouse, mc_global.tty.xterm_flag);
 359 
 360     // Removing this from the X code let's us type C-c
 361     load_key_defs ();
 362 
 363     keymap_load (!mc_args__nokeymap);
 364 
 365 #ifdef USE_INTERNAL_EDIT
 366     macros_list = g_array_new (TRUE, FALSE, sizeof (macros_t));
 367 #endif
 368 
 369     tty_init_colors (mc_global.tty.disable_colors, mc_args__force_colors, COLOR_MAP_SIZE);
 370 
 371     mc_skin_init (NULL, &mcerror);
 372 
 373     mc_error_message (&mcerror, NULL);
 374 
 375 #ifdef ENABLE_SUBSHELL
 376     // Done here to ensure that the subshell doesn't
 377     // inherit the file descriptors opened below, etc
 378     if (mc_global.tty.use_subshell && mc_global.run_from_parent_mc)
 379     {
 380         char *text;
 381 
 382         text = g_strdup_printf (_ ("%s\nis already running on this terminal.\n"
 383                                    "Subshell support will be disabled."),
 384                                 PACKAGE_NAME);
 385 
 386         const int quit_mc = query_dialog (_ ("Warning"), text, D_ERROR, 2, _ ("&OK"), _ ("&Quit"));
 387 
 388         g_free (text);
 389 
 390         if (quit_mc != 0)
 391         {
 392             // parent mc was found and the user wants to quit mc
 393             mc_global.midnight_shutdown = TRUE;
 394         }
 395 
 396         // quit or not, disable nested subshell
 397         mc_global.tty.use_subshell = FALSE;
 398     }
 399 
 400     if (mc_global.tty.use_subshell)
 401         init_subshell ();
 402 #endif
 403 
 404     if (!mc_global.midnight_shutdown)
 405     {
 406         // Also done after init_subshell, to save any shell init file messages
 407         if (mc_global.tty.console_flag != '\0')
 408             handle_console (CONSOLE_SAVE);
 409 
 410         if (mc_global.tty.alternate_plus_minus)
 411             application_keypad_mode ();
 412 
 413         /* Done after subshell initialization to allow select and paste text by mouse
 414            w/o Shift button in subshell in the native console */
 415         init_mouse ();
 416 
 417         /* Done after tty_enter_ca_mode (tty_init) because in VTE bracketed mode is
 418            separate for the normal and alternate screens */
 419         enable_bracketed_paste ();
 420 
 421         // subshell_prompt is NULL here
 422         mc_prompt = g_strdup ((geteuid () == 0) ? "# " : "$ ");
 423     }
 424 
 425     // Program main loop
 426     if (mc_global.midnight_shutdown)
 427         exit_code = EXIT_SUCCESS;
 428     else
 429         exit_code = do_nc () ? EXIT_SUCCESS : EXIT_FAILURE;
 430 
 431     g_free (mc_prompt);
 432 
 433     disable_bracketed_paste ();
 434 
 435     disable_mouse ();
 436 
 437     // Save the tree store
 438     (void) tree_store_save ();
 439 
 440     keymap_free ();
 441 
 442     /* At exit, do this before vfs_shut():
 443        normally, temporary directory should be empty */
 444     vfs_expire (TRUE);
 445     (void) mc_rmdir (tmp_vpath);
 446     vfs_path_free (tmp_vpath, TRUE);
 447 
 448     // Virtual File System shutdown
 449     vfs_shut ();
 450 
 451     flush_extension_file ();  // does only free memory
 452 
 453     mc_skin_deinit ();
 454     tty_colors_done ();
 455 
 456     tty_shutdown ();
 457 
 458     done_setup ();
 459 
 460     if (mc_global.tty.console_flag != '\0' && (quit & SUBSHELL_EXIT) == 0)
 461         handle_console (CONSOLE_RESTORE);
 462     if (mc_global.tty.alternate_plus_minus)
 463         numeric_keypad_mode ();
 464 
 465     (void) my_signal (SIGCHLD, SIG_DFL);  // Disable the SIGCHLD handler
 466 
 467     if (mc_global.tty.console_flag != '\0')
 468         handle_console (CONSOLE_DONE);
 469 
 470     if (mc_global.mc_run_mode == MC_RUN_FULL && mc_args__last_wd_file != NULL && last_wd_str != NULL
 471         && !print_last_revert)
 472     {
 473         const int last_wd_fd =
 474             open (mc_args__last_wd_file, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
 475 
 476         if (last_wd_fd != -1)
 477         {
 478             MC_UNUSED const ssize_t ret1 = write (last_wd_fd, last_wd_str, strlen (last_wd_str));
 479             MC_UNUSED const int ret2 = close (last_wd_fd);
 480         }
 481     }
 482 
 483     g_free (last_wd_str);
 484 
 485     mc_shell_deinit ();
 486 
 487     done_key ();
 488 
 489 #ifdef USE_INTERNAL_EDIT
 490     if (macros_list != NULL)
 491     {
 492         guint i;
 493 
 494         for (i = 0; i < macros_list->len; i++)
 495         {
 496             macros_t *macros;
 497 
 498             macros = &g_array_index (macros_list, struct macros_t, i);
 499             if (macros != NULL && macros->macro != NULL)
 500                 (void) g_array_free (macros->macro, TRUE);
 501         }
 502         (void) g_array_free (macros_list, TRUE);
 503     }
 504 #endif
 505 
 506     str_uninit_strings ();
 507 
 508     if (mc_global.mc_run_mode != MC_RUN_EDITOR)
 509         g_free (mc_run_param0);
 510 #ifdef USE_INTERNAL_EDIT
 511     else
 512         g_list_free_full ((GList *) mc_run_param0, (GDestroyNotify) edit_arg_free);
 513 #endif
 514 
 515     g_free (mc_run_param1);
 516     g_free (saved_other_dir);
 517 
 518     mc_config_deinit_config_paths ();
 519 
 520     (void) mc_event_deinit (&mcerror);
 521     if (mcerror != NULL)
 522     {
 523         fprintf (stderr, _ ("\nFailed while close:\n%s\n"), mcerror->message);
 524         g_error_free (mcerror);
 525         exit_code = EXIT_FAILURE;
 526     }
 527 
 528     (void) putchar ('\n');  // Hack to make shell's prompt start at left of screen
 529 
 530     return exit_code;
 531 }
 532 
 533 /* --------------------------------------------------------------------------------------------- */

/*   */