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) 1994-2025
   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 <ctype.h>
  35 #include <errno.h>
  36 #include <locale.h>
  37 #include <pwd.h>  // for username in xterm title
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <sys/types.h>
  42 #include <sys/wait.h>
  43 #include <signal.h>
  44 #include <unistd.h>  // getsid()
  45 
  46 #include "lib/global.h"
  47 
  48 #include "lib/event.h"
  49 #include "lib/tty/tty.h"
  50 #include "lib/tty/key.h"    // For init_key()
  51 #include "lib/tty/mouse.h"  // init_mouse()
  52 #include "lib/skin.h"
  53 #include "lib/filehighlight.h"
  54 #include "lib/fileloc.h"
  55 #include "lib/strutil.h"
  56 #include "lib/util.h"
  57 #include "lib/vfs/vfs.h"  // vfs_init(), vfs_shut()
  58 
  59 #include "filemanager/filemanager.h"
  60 #include "filemanager/treestore.h"  // tree_store_save
  61 #include "filemanager/layout.h"
  62 #include "filemanager/ext.h"      // flush_extension_file()
  63 #include "filemanager/command.h"  // cmdline
  64 #include "filemanager/panel.h"    // panalized_panel
  65 #include "filemanager/filenot.h"  // my_rmdir()
  66 
  67 #ifdef USE_INTERNAL_EDIT
  68 #include "editor/edit.h"  // edit_arg_free()
  69 #endif
  70 
  71 #include "vfs/plugins_init.h"
  72 
  73 #include "events_init.h"
  74 #include "args.h"
  75 #ifdef ENABLE_SUBSHELL
  76 #include "subshell/subshell.h"
  77 #endif
  78 #include "keymap.h"
  79 #include "setup.h"  // load_setup()
  80 
  81 #include "lib/charsets.h"
  82 #include "selcodepage.h"
  83 
  84 #include "consaver/cons.saver.h"  // cons_saver_pid
  85 
  86 /*** global variables ****************************************************************************/
  87 
  88 /*** file scope macro definitions ****************************************************************/
  89 
  90 /*** file scope type declarations ****************************************************************/
  91 
  92 /*** forward declarations (file scope functions) *************************************************/
  93 
  94 /*** file scope variables ************************************************************************/
  95 
  96 /* --------------------------------------------------------------------------------------------- */
  97 /*** file scope functions ************************************************************************/
  98 /* --------------------------------------------------------------------------------------------- */
  99 
 100 /** POSIX version.  The only version we support.  */
 101 static void
 102 OS_Setup (void)
     /*   */
 103 {
 104     mc_shell_init ();
 105 
 106     // This is the directory, where MC was installed, on Unix this is DATADIR
 107     // and can be overridden by the MC_DATADIR environment variable
 108     const char *datadir_env = g_getenv ("MC_DATADIR");
 109 
 110     if (datadir_env != NULL)
 111         mc_global.sysconfig_dir = g_strdup (datadir_env);
 112     else
 113         mc_global.sysconfig_dir = g_strdup (SYSCONFDIR);
 114 
 115     mc_global.share_data_dir = g_strdup (DATADIR);
 116 }
 117 
 118 /* --------------------------------------------------------------------------------------------- */
 119 
 120 static void
 121 sigchld_handler_no_subshell (int sig)
     /*   */
 122 {
 123 #ifdef __linux__
 124     int pid, status;
 125 
 126     if (mc_global.tty.console_flag == '\0')
 127         return;
 128 
 129     /* COMMENT: if it were true that after the call to handle_console(..INIT)
 130        the value of mc_global.tty.console_flag never changed, we could simply not install
 131        this handler at all if (!mc_global.tty.console_flag && !mc_global.tty.use_subshell). */
 132 
 133     /* That comment is no longer true.  We need to wait() on a sigchld
 134        handler (that's at least what the tarfs code expects currently). */
 135 
 136     pid = waitpid (cons_saver_pid, &status, WUNTRACED | WNOHANG);
 137 
 138     if (pid == cons_saver_pid)
 139     {
 140         if (WIFSTOPPED (status))
 141         {
 142             // Someone has stopped cons.saver - restart it
 143             kill (pid, SIGCONT);
 144         }
 145         else
 146         {
 147             // cons.saver has died - disable console saving
 148             handle_console (CONSOLE_DONE);
 149             mc_global.tty.console_flag = '\0';
 150         }
 151     }
 152     // If we got here, some other child exited; ignore it
 153 #endif
 154 
 155     (void) sig;
 156 }
 157 
 158 /* --------------------------------------------------------------------------------------------- */
 159 
 160 static void
 161 init_sigchld (void)
     /*   */
 162 {
 163     struct sigaction sigchld_action;
 164 
 165     memset (&sigchld_action, 0, sizeof (sigchld_action));
 166     sigchld_action.sa_handler =
 167 #ifdef ENABLE_SUBSHELL
 168         mc_global.tty.use_subshell ? sigchld_handler :
 169 #endif
 170                                    sigchld_handler_no_subshell;
 171 
 172     sigemptyset (&sigchld_action.sa_mask);
 173 
 174 #ifdef SA_RESTART
 175     sigchld_action.sa_flags = SA_RESTART;
 176 #endif
 177 
 178     if (my_sigaction (SIGCHLD, &sigchld_action, NULL) == -1)
 179     {
 180 #ifdef ENABLE_SUBSHELL
 181         /*
 182          * This may happen on QNX Neutrino 6, where SA_RESTART
 183          * is defined but not implemented.  Fallback to no subshell.
 184          */
 185         mc_global.tty.use_subshell = FALSE;
 186 #endif
 187     }
 188 }
 189 
 190 /* --------------------------------------------------------------------------------------------- */
 191 /**
 192  * Check MC_SID to prevent running one mc from another.
 193  *
 194  * @return TRUE if no parent mc in our session was found, FALSE otherwise.
 195  */
 196 
 197 static gboolean
 198 check_sid (void)
     /*   */
 199 {
 200     pid_t my_sid, old_sid;
 201     const char *sid_str;
 202 
 203     sid_str = getenv ("MC_SID");
 204     if (sid_str == NULL)
 205         return TRUE;
 206 
 207     old_sid = (pid_t) strtol (sid_str, NULL, 0);
 208     if (old_sid == 0)
 209         return TRUE;
 210 
 211     my_sid = getsid (0);
 212     if (my_sid == -1)
 213         return TRUE;
 214 
 215     // The parent mc is in a different session, it's OK
 216     return (old_sid != my_sid);
 217 }
 218 
 219 /* --------------------------------------------------------------------------------------------- */
 220 /*** public functions ****************************************************************************/
 221 /* --------------------------------------------------------------------------------------------- */
 222 
 223 int
 224 main (int argc, char *argv[])
     /*   */
 225 {
 226     GError *mcerror = NULL;
 227     int exit_code = EXIT_FAILURE;
 228     const char *tmpdir = NULL;
 229 
 230     mc_global.run_from_parent_mc = !check_sid ();
 231 
 232     // We had LC_CTYPE before, LC_ALL includs LC_TYPE as well
 233 #ifdef HAVE_SETLOCALE
 234     (void) setlocale (LC_ALL, "");
 235 #endif
 236     (void) bindtextdomain (PACKAGE, LOCALEDIR);
 237     (void) textdomain (PACKAGE);
 238 
 239     // do this before args parsing
 240     str_init_strings (NULL);
 241 
 242     mc_setup_run_mode (argv);  // are we mc? editor? viewer? etc...
 243 
 244     if (!mc_args_parse (&argc, &argv, "mc", &mcerror))
 245     {
 246     startup_exit_falure:
 247         fprintf (stderr, _ ("Failed to run:\n%s\n"), mcerror->message);
 248         g_error_free (mcerror);
 249     startup_exit_ok:
 250         mc_shell_deinit ();
 251         str_uninit_strings ();
 252         return exit_code;
 253     }
 254 
 255     /* check terminal type
 256      * $TERM must be set and not empty
 257      * mc_global.tty.xterm_flag is used in init_key() and tty_init()
 258      * Do this after mc_args_parse() where mc_args__force_xterm is set up.
 259      */
 260     mc_global.tty.xterm_flag = tty_check_xterm_compat (mc_args__force_xterm);
 261 
 262     // do this before mc_args_show_info () to view paths in the --datadir-info output
 263     OS_Setup ();
 264 
 265     if (!g_path_is_absolute (mc_config_get_home_dir ()))
 266     {
 267         mc_propagate_error (&mcerror, 0, "%s: %s", _ ("Home directory path is not absolute"),
 268                             mc_config_get_home_dir ());
 269         mc_event_deinit (NULL);
 270         goto startup_exit_falure;
 271     }
 272 
 273     if (!mc_args_show_info ())
 274     {
 275         exit_code = EXIT_SUCCESS;
 276         goto startup_exit_ok;
 277     }
 278 
 279     if (!events_init (&mcerror))
 280         goto startup_exit_falure;
 281 
 282     mc_config_init_config_paths (&mcerror);
 283     if (mcerror != NULL)
 284     {
 285         mc_event_deinit (NULL);
 286         goto startup_exit_falure;
 287     }
 288 
 289     vfs_init ();
 290     vfs_plugins_init ();
 291 
 292     load_setup ();
 293 
 294     // Must be done after load_setup because depends on mc_global.vfs.cd_symlinks
 295     vfs_setup_work_dir ();
 296 
 297     // Set up temporary directory after VFS initialization
 298     tmpdir = mc_tmpdir ();
 299 
 300     /* do this after vfs initialization and vfs working directory setup
 301        due to mc_setctl() and mcedit_arg_vpath_new() calls in mc_setup_by_args() */
 302     if (!mc_setup_by_args (argc, argv, &mcerror))
 303     {
 304         /* At exit, do this before vfs_shut():
 305            normally, temporary directory should be empty */
 306         vfs_expire (TRUE);
 307         (void) my_rmdir (tmpdir);
 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);
 370 
 371     mc_skin_init (NULL, &mcerror);
 372     dlg_set_default_colors ();
 373     input_set_default_colors ();
 374     if (mc_global.mc_run_mode == MC_RUN_FULL)
 375         command_set_default_colors ();
 376 
 377     mc_error_message (&mcerror, NULL);
 378 
 379 #ifdef ENABLE_SUBSHELL
 380     // Done here to ensure that the subshell doesn't
 381     // inherit the file descriptors opened below, etc
 382     if (mc_global.tty.use_subshell && mc_global.run_from_parent_mc)
 383     {
 384         const int quit_mc =
 385             query_dialog (_ ("Warning"),
 386                           _ ("GNU Midnight Commander\nis already running on this terminal.\n"
 387                              "Subshell support will be disabled."),
 388                           D_ERROR, 2, _ ("&OK"), _ ("&Quit"));
 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 = (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     disable_bracketed_paste ();
 432 
 433     disable_mouse ();
 434 
 435     // Save the tree store
 436     (void) tree_store_save ();
 437 
 438     keymap_free ();
 439 
 440     /* At exit, do this before vfs_shut():
 441        normally, temporary directory should be empty */
 442     vfs_expire (TRUE);
 443     (void) my_rmdir (tmpdir);
 444 
 445     // Virtual File System shutdown
 446     vfs_shut ();
 447 
 448     flush_extension_file ();  // does only free memory
 449 
 450     mc_skin_deinit ();
 451     tty_colors_done ();
 452 
 453     tty_shutdown ();
 454 
 455     done_setup ();
 456 
 457     if (mc_global.tty.console_flag != '\0' && (quit & SUBSHELL_EXIT) == 0)
 458         handle_console (CONSOLE_RESTORE);
 459     if (mc_global.tty.alternate_plus_minus)
 460         numeric_keypad_mode ();
 461 
 462     (void) my_signal (SIGCHLD, SIG_DFL);  // Disable the SIGCHLD handler
 463 
 464     if (mc_global.tty.console_flag != '\0')
 465         handle_console (CONSOLE_DONE);
 466 
 467     if (mc_global.mc_run_mode == MC_RUN_FULL && mc_args__last_wd_file != NULL && last_wd_str != NULL
 468         && !print_last_revert)
 469     {
 470         const int last_wd_fd =
 471             open (mc_args__last_wd_file, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
 472         if (last_wd_fd != -1)
 473         {
 474             MC_UNUSED const ssize_t ret1 = write (last_wd_fd, last_wd_str, strlen (last_wd_str));
 475             MC_UNUSED const int ret2 = close (last_wd_fd);
 476         }
 477     }
 478 
 479     g_free (last_wd_str);
 480 
 481     mc_shell_deinit ();
 482 
 483     done_key ();
 484 
 485 #ifdef USE_INTERNAL_EDIT
 486     if (macros_list != NULL)
 487     {
 488         guint i;
 489 
 490         for (i = 0; i < macros_list->len; i++)
 491         {
 492             macros_t *macros;
 493 
 494             macros = &g_array_index (macros_list, struct macros_t, i);
 495             if (macros != NULL && macros->macro != NULL)
 496                 (void) g_array_free (macros->macro, TRUE);
 497         }
 498         (void) g_array_free (macros_list, TRUE);
 499     }
 500 #endif
 501 
 502     str_uninit_strings ();
 503 
 504     if (mc_global.mc_run_mode != MC_RUN_EDITOR)
 505         g_free (mc_run_param0);
 506 #ifdef USE_INTERNAL_EDIT
 507     else
 508         g_list_free_full ((GList *) mc_run_param0, (GDestroyNotify) edit_arg_free);
 509 #endif
 510 
 511     g_free (mc_run_param1);
 512     g_free (saved_other_dir);
 513 
 514     mc_config_deinit_config_paths ();
 515 
 516     (void) mc_event_deinit (&mcerror);
 517     if (mcerror != NULL)
 518     {
 519         fprintf (stderr, _ ("\nFailed while close:\n%s\n"), mcerror->message);
 520         g_error_free (mcerror);
 521         exit_code = EXIT_FAILURE;
 522     }
 523 
 524     (void) putchar ('\n');  // Hack to make shell's prompt start at left of screen
 525 
 526     return exit_code;
 527 }
 528 
 529 /* --------------------------------------------------------------------------------------------- */

/*   */