lib/shell.c

lib/shell.c
/* */
This source file includes following definitions.
mc_shell_get_installed_in_system
mc_shell_get_name_env
mc_shell_get_from_env
mc_shell_recognize_real_path
mc_shell_recognize_path
mc_shell_init
mc_shell_deinit
   1 /*
   2    Provides a functions for working with shell.
   3 
   4    Copyright (C) 2006-2025
   5    Free Software Foundation, Inc.
   6 
   7    Written by:
   8    Slava Zanko <slavazanko@gmail.com>, 2015.
   9 
  10    This file is part of the Midnight Commander.
  11 
  12    The Midnight Commander is free software: you can redistribute it
  13    and/or modify it under the terms of the GNU General Public License as
  14    published by the Free Software Foundation, either version 3 of the License,
  15    or (at your option) any later version.
  16 
  17    The Midnight Commander is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21 
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24  */
  25 
  26 /** \file shell.c
  27  *  \brief Source: provides a functions for working with shell.
  28  */
  29 
  30 #include <config.h>
  31 
  32 #include <pwd.h>                /* for username in xterm title */
  33 #include <stdarg.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 
  37 #include "global.h"
  38 #include "util.h"
  39 
  40 /*** global variables ****************************************************************************/
  41 
  42 /*** file scope macro definitions ****************************************************************/
  43 
  44 /*** file scope type declarations ****************************************************************/
  45 
  46 /*** forward declarations (file scope functions) *************************************************/
  47 
  48 /*** file scope variables ************************************************************************/
  49 
  50 static char rp_shell[PATH_MAX];
  51 
  52 /* --------------------------------------------------------------------------------------------- */
  53 /*** file scope functions ************************************************************************/
  54 /* --------------------------------------------------------------------------------------------- */
  55 /**
  56  * Get a system shell.
  57  *
  58  * @return newly allocated mc_shell_t object with shell name
  59  */
  60 
  61 static mc_shell_t *
  62 mc_shell_get_installed_in_system (void)
     /*   */
  63 {
  64     mc_shell_t *mc_shell;
  65 
  66     mc_shell = g_new0 (mc_shell_t, 1);
  67 
  68     /* 3rd choice: look for existing shells supported as MC subshells.  */
  69     if (access ("/bin/bash", X_OK) == 0)
  70         mc_shell->path = g_strdup ("/bin/bash");
  71     else if (access ("/bin/zsh", X_OK) == 0)
  72         mc_shell->path = g_strdup ("/bin/zsh");
  73     else if (access ("/bin/oksh", X_OK) == 0)
  74         mc_shell->path = g_strdup ("/bin/oksh");
  75     else if (access ("/bin/ksh", X_OK) == 0)
  76         mc_shell->path = g_strdup ("/bin/ksh");
  77     else if (access ("/bin/ksh93", X_OK) == 0)
  78         mc_shell->path = g_strdup ("/bin/ksh93");
  79     else if (access ("/bin/ash", X_OK) == 0)
  80         mc_shell->path = g_strdup ("/bin/ash");
  81     else if (access ("/bin/dash", X_OK) == 0)
  82         mc_shell->path = g_strdup ("/bin/dash");
  83     else if (access ("/bin/busybox", X_OK) == 0)
  84         mc_shell->path = g_strdup ("/bin/busybox");
  85     else if (access ("/bin/tcsh", X_OK) == 0)
  86         mc_shell->path = g_strdup ("/bin/tcsh");
  87     else if (access ("/bin/csh", X_OK) == 0)
  88         mc_shell->path = g_strdup ("/bin/csh");
  89     else if (access ("/bin/mksh", X_OK) == 0)
  90         mc_shell->path = g_strdup ("/bin/mksh");
  91     /* No fish as fallback because it is so much different from other shells and
  92      * in a way exotic (even though user-friendly by name) that we should not
  93      * present it as a subshell without the user's explicit intention. We rather
  94      * will not use a subshell but just a command line.
  95      * else if (access("/bin/fish", X_OK) == 0)
  96      *     mc_global.tty.shell = g_strdup ("/bin/fish");
  97      */
  98     else
  99         /* Fallback and last resort: system default shell */
 100         mc_shell->path = g_strdup ("/bin/sh");
 101 
 102     return mc_shell;
 103 }
 104 
 105 /* --------------------------------------------------------------------------------------------- */
 106 
 107 static char *
 108 mc_shell_get_name_env (void)
     /*   */
 109 {
 110     const char *shell_env;
 111     char *shell_name = NULL;
 112 
 113     shell_env = g_getenv ("SHELL");
 114     if ((shell_env == NULL) || (shell_env[0] == '\0'))
 115     {
 116         /* 2nd choice: user login shell */
 117         struct passwd *pwd;
 118 
 119         pwd = getpwuid (geteuid ());
 120         if (pwd != NULL)
 121             shell_name = g_strdup (pwd->pw_shell);
 122     }
 123     else
 124         /* 1st choice: SHELL environment variable */
 125         shell_name = g_strdup (shell_env);
 126 
 127     return shell_name;
 128 }
 129 
 130 /* --------------------------------------------------------------------------------------------- */
 131 
 132 static mc_shell_t *
 133 mc_shell_get_from_env (void)
     /*   */
 134 {
 135     mc_shell_t *mc_shell = NULL;
 136 
 137     char *shell_name;
 138 
 139     shell_name = mc_shell_get_name_env ();
 140 
 141     if (shell_name != NULL)
 142     {
 143         mc_shell = g_new0 (mc_shell_t, 1);
 144         mc_shell->path = shell_name;
 145     }
 146 
 147     return mc_shell;
 148 }
 149 
 150 /* --------------------------------------------------------------------------------------------- */
 151 
 152 static void
 153 mc_shell_recognize_real_path (mc_shell_t *mc_shell)
     /*   */
 154 {
 155     if (strstr (mc_shell->path, "/zsh") != NULL || strstr (mc_shell->real_path, "/zsh") != NULL
 156         || getenv ("ZSH_VERSION") != NULL)
 157     {
 158         /* Also detects ksh symlinked to zsh */
 159         mc_shell->type = SHELL_ZSH;
 160         mc_shell->name = "zsh";
 161     }
 162     else if (strstr (mc_shell->path, "/tcsh") != NULL
 163              || strstr (mc_shell->real_path, "/tcsh") != NULL)
 164     {
 165         /* Also detects csh symlinked to tcsh */
 166         mc_shell->type = SHELL_TCSH;
 167         mc_shell->name = "tcsh";
 168     }
 169     else if (strstr (mc_shell->path, "/csh") != NULL
 170              || strstr (mc_shell->real_path, "/csh") != NULL)
 171     {
 172         mc_shell->type = SHELL_TCSH;
 173         mc_shell->name = "csh";
 174     }
 175     else if (strstr (mc_shell->path, "/fish") != NULL
 176              || strstr (mc_shell->real_path, "/fish") != NULL)
 177     {
 178         mc_shell->type = SHELL_FISH;
 179         mc_shell->name = "fish";
 180     }
 181     else if (strstr (mc_shell->path, "/dash") != NULL
 182              || strstr (mc_shell->real_path, "/dash") != NULL)
 183     {
 184         /* Debian ash (also found if symlinked to by ash/sh) */
 185         mc_shell->type = SHELL_DASH;
 186         mc_shell->name = "dash";
 187     }
 188     else if (strstr (mc_shell->real_path, "/busybox") != NULL)
 189     {
 190         /* If shell is symlinked to busybox, assume it is an ash, even though theoretically
 191          * it could also be a hush (a mini shell for non-MMU systems deactivated by default).
 192          * For simplicity's sake we assume that busybox always contains an ash, not a hush.
 193          * On embedded platforms or on server systems, /bin/sh often points to busybox.
 194          * Sometimes even bash is symlinked to busybox (CONFIG_FEATURE_BASH_IS_ASH option),
 195          * so we need to check busybox symlinks *before* checking for the name "bash"
 196          * in order to avoid that case. */
 197         mc_shell->type = SHELL_ASH_BUSYBOX;
 198         mc_shell->name = mc_shell->path;
 199     }
 200     else if (strstr (mc_shell->path, "/ksh") != NULL
 201              || strstr (mc_shell->real_path, "/ksh") != NULL
 202              || strstr (mc_shell->path, "/ksh93") != NULL
 203              || strstr (mc_shell->real_path, "/ksh93") != NULL
 204              || strstr (mc_shell->path, "/oksh") != NULL
 205              || strstr (mc_shell->real_path, "/oksh") != NULL)
 206     {
 207         mc_shell->type = SHELL_KSH;
 208         mc_shell->name = "ksh";
 209     }
 210     else if (strstr (mc_shell->path, "/mksh") != NULL
 211              || strstr (mc_shell->real_path, "/mksh") != NULL)
 212     {
 213         mc_shell->type = SHELL_MKSH;
 214         mc_shell->name = "mksh";
 215     }
 216     else
 217         mc_shell->type = SHELL_NONE;
 218 }
 219 
 220 /* --------------------------------------------------------------------------------------------- */
 221 
 222 static void
 223 mc_shell_recognize_path (mc_shell_t *mc_shell)
     /*   */
 224 {
 225     /* If shell is not symlinked to busybox, it is safe to assume it is a real shell */
 226     if (strstr (mc_shell->path, "/bash") != NULL || getenv ("BASH_VERSION") != NULL)
 227     {
 228         mc_shell->type = SHELL_BASH;
 229         mc_shell->name = "bash";
 230     }
 231     else if (strstr (mc_shell->path, "/sh") != NULL)
 232     {
 233         mc_shell->type = SHELL_SH;
 234         mc_shell->name = "sh";
 235     }
 236     else if (strstr (mc_shell->path, "/ash") != NULL || getenv ("BB_ASH_VERSION") != NULL)
 237     {
 238         mc_shell->type = SHELL_ASH_BUSYBOX;
 239         mc_shell->name = "ash";
 240     }
 241     else if (strstr (mc_shell->path, "/ksh") != NULL
 242              || strstr (mc_shell->path, "/ksh93") != NULL
 243              || strstr (mc_shell->path, "/oksh") != NULL
 244              || (getenv ("KSH_VERSION") != NULL
 245                  && strstr (getenv ("KSH_VERSION"), "PD KSH") != NULL))
 246     {
 247         mc_shell->type = SHELL_KSH;
 248         mc_shell->name = "ksh";
 249     }
 250     else if (strstr (mc_shell->path, "/mksh") != NULL
 251              || (getenv ("KSH_VERSION") != NULL
 252                  && strstr (getenv ("KSH_VERSION"), "MIRBSD KSH") != NULL))
 253     {
 254         mc_shell->type = SHELL_MKSH;
 255         mc_shell->name = "mksh";
 256     }
 257     else
 258         mc_shell->type = SHELL_NONE;
 259 }
 260 
 261 /* --------------------------------------------------------------------------------------------- */
 262 /*** public functions ****************************************************************************/
 263 /* --------------------------------------------------------------------------------------------- */
 264 
 265 void
 266 mc_shell_init (void)
     /*   */
 267 {
 268     mc_shell_t *mc_shell;
 269 
 270     mc_shell = mc_shell_get_from_env ();
 271 
 272     if (mc_shell == NULL)
 273         mc_shell = mc_shell_get_installed_in_system ();
 274 
 275     mc_shell->real_path = mc_realpath (mc_shell->path, rp_shell);
 276 
 277     /* Find out what type of shell we have. Also consider real paths (resolved symlinks)
 278      * because e.g. csh might point to tcsh, ash to dash or busybox, sh to anything. */
 279 
 280     if (mc_shell->real_path != NULL)
 281         mc_shell_recognize_real_path (mc_shell);
 282 
 283     if (mc_shell->type == SHELL_NONE)
 284         mc_shell_recognize_path (mc_shell);
 285 
 286     if (mc_shell->type == SHELL_NONE)
 287         mc_global.tty.use_subshell = FALSE;
 288 
 289     mc_global.shell = mc_shell;
 290 }
 291 
 292 /* --------------------------------------------------------------------------------------------- */
 293 
 294 void
 295 mc_shell_deinit (void)
     /*   */
 296 {
 297     if (mc_global.shell != NULL)
 298     {
 299         g_free (mc_global.shell->path);
 300         MC_PTR_FREE (mc_global.shell);
 301     }
 302 }
 303 
 304 /* --------------------------------------------------------------------------------------------- */
/* */
root/lib/shell.c

DEFINITIONS
