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 <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 #include "filemanager/filenot.h"  // my_rmdir()
  64 
  65 #ifdef USE_INTERNAL_EDIT
  66 #include "editor/edit.h"  // edit_arg_free()
  67 #endif
  68 
  69 #include "vfs/plugins_init.h"
  70 
  71 #include "events_init.h"
  72 #include "args.h"
  73 #ifdef ENABLE_SUBSHELL
  74 #include "subshell/subshell.h"
  75 #endif
  76 #include "keymap.h"
  77 #include "setup.h"  // load_setup()
  78 
  79 #include "lib/charsets.h"
  80 #include "selcodepage.h"
  81 
  82 #include "consaver/cons.saver.h"  // cons_saver_pid
  83 
  84 /*** global variables ****************************************************************************/
  85 
  86 /*** file scope macro definitions ****************************************************************/
  87 
  88 /*** file scope type declarations ****************************************************************/
  89 
  90 /*** forward declarations (file scope functions) *************************************************/
  91 
  92 /*** file scope variables ************************************************************************/
  93 
  94 /* --------------------------------------------------------------------------------------------- */
  95 /*** file scope functions ************************************************************************/
  96 /* --------------------------------------------------------------------------------------------- */
  97 
  98 /** POSIX version.  The only version we support.  */
  99 static void
 100 OS_Setup (void)
     /*   */
 101 {
 102     mc_shell_init ();
 103 
 104     // This is the directory, where MC was installed, on Unix this is DATADIR
 105     // and can be overridden by the MC_DATADIR environment variable
 106     const char *datadir_env = g_getenv ("MC_DATADIR");
 107 
 108     if (datadir_env != NULL)
 109         mc_global.sysconfig_dir = g_strdup (datadir_env);
 110     else
 111         mc_global.sysconfig_dir = g_strdup (SYSCONFDIR);
 112 
 113     mc_global.share_data_dir = g_strdup (DATADIR);
 114 }
 115 
 116 /* --------------------------------------------------------------------------------------------- */
 117 
 118 static void
 119 sigchld_handler_no_subshell (int sig)
     /*   */
 120 {
 121 #ifdef __linux__
 122     int pid, status;
 123 
 124     if (mc_global.tty.console_flag == '\0')
 125         return;
 126 
 127     /* COMMENT: if it were true that after the call to handle_console(..INIT)
 128        the value of mc_global.tty.console_flag never changed, we could simply not install
 129        this handler at all if (!mc_global.tty.console_flag && !mc_global.tty.use_subshell). */
 130 
 131     /* That comment is no longer true.  We need to wait() on a sigchld
 132        handler (that's at least what the tarfs code expects currently). */
 133 
 134     pid = waitpid (cons_saver_pid, &status, WUNTRACED | WNOHANG);
 135 
 136     if (pid == cons_saver_pid)
 137     {
 138         if (WIFSTOPPED (status))
 139         {
 140             // Someone has stopped cons.saver - restart it
 141             kill (pid, SIGCONT);
 142         }
 143         else
 144         {
 145             // cons.saver has died - disable console saving
 146             handle_console (CONSOLE_DONE);
 147             mc_global.tty.console_flag = '\0';
 148         }
 149     }
 150     // If we got here, some other child exited; ignore it
 151 #endif
 152 
 153     (void) sig;
 154 }
 155 
 156 /* --------------------------------------------------------------------------------------------- */
 157 
 158 static void
 159 init_sigchld (void)
     /*   */
 160 {
 161     struct sigaction sigchld_action;
 162 
 163     memset (&sigchld_action, 0, sizeof (sigchld_action));
 164     sigchld_action.sa_handler =
 165 #ifdef ENABLE_SUBSHELL
 166         mc_global.tty.use_subshell ? sigchld_handler :
 167 #endif
 168                                    sigchld_handler_no_subshell;
 169 
 170     sigemptyset (&sigchld_action.sa_mask);
 171 
 172 #ifdef SA_RESTART
 173     sigchld_action.sa_flags = SA_RESTART;
 174 #endif
 175 
 176     if (my_sigaction (SIGCHLD, &sigchld_action, NULL) == -1)
 177     {
 178 #ifdef ENABLE_SUBSHELL
 179         /*
 180          * This may happen on QNX Neutrino 6, where SA_RESTART
 181          * is defined but not implemented.  Fallback to no subshell.
 182          */
 183         mc_global.tty.use_subshell = FALSE;
 184 #endif
 185     }
 186 }
 187 
 188 /* --------------------------------------------------------------------------------------------- */
 189 /**
 190  * Check MC_SID to prevent running one mc from another.
 191  *
 192  * @return TRUE if no parent mc in our session was found, FALSE otherwise.
 193  */
 194 
 195 static gboolean
 196 check_sid (void)
     /*   */
 197 {
 198     pid_t my_sid, old_sid;
 199     const char *sid_str;
 200 
 201     sid_str = getenv ("MC_SID");
 202     if (sid_str == NULL)
 203         return TRUE;
 204 
 205     old_sid = (pid_t) strtol (sid_str, NULL, 0);
 206     if (old_sid == 0)
 207         return TRUE;
 208 
 209     my_sid = getsid (0);
 210     if (my_sid == -1)
 211         return TRUE;
 212 
 213     // The parent mc is in a different session, it's OK
 214     return (old_sid != my_sid);
 215 }
 216 
 217 /* --------------------------------------------------------------------------------------------- */
 218 /*** public functions ****************************************************************************/
 219 /* --------------------------------------------------------------------------------------------- */
 220 
 221 int
 222 main (int argc, char *argv[])
     /*   */
 223 {
 224     GError *mcerror = NULL;
 225     int exit_code = EXIT_FAILURE;
 226     const char *tmpdir = NULL;
 227 
 228     mc_global.run_from_parent_mc = !check_sid ();
 229 
 230     // We had LC_CTYPE before, LC_ALL includs LC_TYPE as well
 231 #ifdef HAVE_SETLOCALE
 232     (void) setlocale (LC_ALL, "");
 233 #endif
 234     (void) bindtextdomain (PACKAGE, LOCALEDIR);
 235     (void) textdomain (PACKAGE);
 236 
 237     // do this before args parsing
 238     str_init_strings (NULL);
 239 
 240     mc_setup_run_mode (argv);  // are we mc? editor? viewer? etc...
 241 
 242     if (!mc_args_parse (&argc, &argv, "mc", &mcerror))
 243     {
 244     startup_exit_falure:
 245         fprintf (stderr, _ ("Failed to run:\n%s\n"), mcerror->message);
 246         g_error_free (mcerror);
 247     startup_exit_ok:
 248         mc_shell_deinit ();
 249         str_uninit_strings ();
 250         return exit_code;
 251     }
 252 
 253     /* check terminal type
 254      * $TERM must be set and not empty
 255      * mc_global.tty.xterm_flag is used in init_key() and tty_init()
 256      * Do this after mc_args_parse() where mc_args__force_xterm is set up.
 257      */
 258     mc_global.tty.xterm_flag = tty_check_xterm_compat (mc_args__force_xterm);
 259 
 260     // do this before mc_args_show_info () to view paths in the --datadir-info output
 261     OS_Setup ();
 262 
 263     if (!g_path_is_absolute (mc_config_get_home_dir ()))
 264     {
 265         mc_propagate_error (&mcerror, 0, "%s: %s", _ ("Home directory path is not absolute"),
 266                             mc_config_get_home_dir ());
 267         mc_event_deinit (NULL);
 268         goto startup_exit_falure;
 269     }
 270 
 271     if (!mc_args_show_info ())
 272     {
 273         exit_code = EXIT_SUCCESS;
 274         goto startup_exit_ok;
 275     }
 276 
 277     if (!events_init (&mcerror))
 278         goto startup_exit_falure;
 279 
 280     mc_config_init_config_paths (&mcerror);
 281     if (mcerror != NULL)
 282     {
 283         mc_event_deinit (NULL);
 284         goto startup_exit_falure;
 285     }
 286 
 287     vfs_init ();
 288     vfs_plugins_init ();
 289 
 290     load_setup ();
 291 
 292     // Must be done after load_setup because depends on mc_global.vfs.cd_symlinks
 293     vfs_setup_work_dir ();
 294 
 295     // Set up temporary directory after VFS initialization
 296     tmpdir = mc_tmpdir ();
 297 
 298     /* do this after vfs initialization and vfs working directory setup
 299        due to mc_setctl() and mcedit_arg_vpath_new() calls in mc_setup_by_args() */
 300     if (!mc_setup_by_args (argc, argv, &mcerror))
 301     {
 302         /* At exit, do this before vfs_shut():
 303            normally, temporary directory should be empty */
 304         vfs_expire (TRUE);
 305         (void) my_rmdir (tmpdir);
 306 
 307         vfs_shut ();
 308         done_setup ();
 309         g_free (saved_other_dir);
 310         mc_event_deinit (NULL);
 311         goto startup_exit_falure;
 312     }
 313 
 314     /* Resolve the other_dir panel option.
 315      * 1. Must be done after vfs_setup_work_dir().
 316      * 2. Must be done after mc_setup_by_args() because of mc_run_mode.
 317      */
 318     if (mc_global.mc_run_mode == MC_RUN_FULL)
 319     {
 320         char *buffer;
 321         vfs_path_t *vpath;
 322 
 323         buffer = mc_config_get_string (mc_global.panels_config, "Dirs", "other_dir", ".");
 324         vpath = vfs_path_from_str (buffer);
 325         if (vfs_file_is_local (vpath))
 326             saved_other_dir = buffer;
 327         else
 328             g_free (buffer);
 329         vfs_path_free (vpath, TRUE);
 330     }
 331 
 332     /* NOTE: This has to be called before tty_init or whatever routine
 333        calls any define_sequence */
 334     init_key ();
 335 
 336     // Must be done before installing the SIGCHLD handler [[FIXME]]
 337     handle_console (CONSOLE_INIT);
 338 
 339 #ifdef ENABLE_SUBSHELL
 340     // Disallow subshell when invoked as standalone viewer or editor from running mc
 341     if (mc_global.mc_run_mode != MC_RUN_FULL && mc_global.run_from_parent_mc)
 342         mc_global.tty.use_subshell = FALSE;
 343 
 344     if (mc_global.tty.use_subshell)
 345         subshell_get_console_attributes ();
 346 #endif
 347 
 348     // Install the SIGCHLD handler; must be done before init_subshell()
 349     init_sigchld ();
 350 
 351     // We need this, since ncurses endwin () doesn't restore the signals
 352     save_stop_handler ();
 353 
 354     // Must be done before init_subshell, to set up the terminal size:
 355     // FIXME: Should be removed and LINES and COLS computed on subshell
 356     tty_init (!mc_args__nomouse, mc_global.tty.xterm_flag);
 357 
 358     // Removing this from the X code let's us type C-c
 359     load_key_defs ();
 360 
 361     keymap_load (!mc_args__nokeymap);
 362 
 363 #ifdef USE_INTERNAL_EDIT
 364     macros_list = g_array_new (TRUE, FALSE, sizeof (macros_t));
 365 #endif
 366 
 367     tty_init_colors (mc_global.tty.disable_colors, mc_args__force_colors);
 368 
 369     mc_skin_init (NULL, &mcerror);
 370     dlg_set_default_colors ();
 371     input_set_default_colors ();
 372     if (mc_global.mc_run_mode == MC_RUN_FULL)
 373         command_set_default_colors ();
 374 
 375     mc_error_message (&mcerror, NULL);
 376 
 377 #ifdef ENABLE_SUBSHELL
 378     // Done here to ensure that the subshell doesn't
 379     // inherit the file descriptors opened below, etc
 380     if (mc_global.tty.use_subshell && mc_global.run_from_parent_mc)
 381     {
 382         char *text;
 383 
 384         text = g_strdup_printf (_ ("%s\nis already running on this terminal.\n"
 385                                    "Subshell support will be disabled."),
 386                                 PACKAGE_NAME);
 387         const int quit_mc = query_dialog (_ ("Warning"), text, D_ERROR, 2, _ ("&OK"), _ ("&Quit"));
 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 = (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 /* --------------------------------------------------------------------------------------------- */

/*   */