Ticket #3748: add support for ksh in subshell

doc/man/mc.1.in

@@ -2406,6 +2406,18 @@ and special keyboard maps in ~/.local/share/mc/inputrc (fallback ~/.inputrc).
 .B ash/dash
 users (BusyBox or Debian) may specify startup commands in ~/.local/share/mc/ashrc (fallback ~/.profile).
 .PP
+.B ksh/oksh
+users (PD ksh variants) may specify startup commands in ~/.local/share/mc/kshrc
+(fallback
+.I ENV
+or ~/.profile).
+.PP
+.B mksh
+users (MirBSD ksh) may specify startup commands in ~/.local/share/mc/mkshrc
+(fallback
+.I ENV
+or ~/.mkshrc).
+.PP
 .B zsh
 users may specify startup commands in ~/.local/share/mc/.zshrc (fallback ~/.zshrc).
 .PP

lib/fileloc.h

@@ -53,6 +53,8 @@
 #define MC_BASHRC_FILE          "bashrc"
 #define MC_ZSHRC_FILE           ".zshrc"
 #define MC_ASHRC_FILE           "ashrc"
+#define MC_KSHRC_FILE           "kshrc"
+#define MC_MKSHRC_FILE          "mkshrc"
 #define MC_INPUTRC_FILE         "inputrc"
 #define MC_CONFIG_FILE          "ini"
 #define MC_EXT_FILE             "mc.ext.ini"

lib/mcconfig/paths.c

@@ -75,6 +75,8 @@ static const struct
     { &mc_data_str, MC_SKINS_DIR },
     { &mc_data_str, VFS_SHELL_PREFIX },
     { &mc_data_str, MC_ASHRC_FILE },
+    { &mc_data_str, MC_KSHRC_FILE },
+    { &mc_data_str, MC_MKSHRC_FILE },
     { &mc_data_str, MC_BASHRC_FILE },
     { &mc_data_str, MC_INPUTRC_FILE },
     { &mc_data_str, MC_ZSHRC_FILE },

lib/shell.c

@@ -80,6 +80,12 @@ mc_shell_get_installed_in_system (void)
         mc_shell->path = g_strdup ("/bin/tcsh");
     else if (access ("/bin/csh", X_OK) == 0)
         mc_shell->path = g_strdup ("/bin/csh");
+    else if (access ("/bin/ksh", X_OK) == 0)
+        mc_shell->path = g_strdup ("/bin/ksh");
+    else if (access ("/bin/oksh", X_OK) == 0)
+        mc_shell->path = g_strdup ("/bin/oksh");
+    else if (access ("/bin/mksh", X_OK) == 0)
+        mc_shell->path = g_strdup ("/bin/mksh");
     /* No fish as fallback because it is so much different from other shells and
      * in a way exotic (even though user-friendly by name) that we should not
      * present it as a subshell without the user's explicit intention. We rather
@@ -189,6 +195,20 @@ mc_shell_recognize_real_path (mc_shell_t *mc_shell)
         mc_shell->type = SHELL_ASH_BUSYBOX;
         mc_shell->name = mc_shell->path;
     }
+    else if (strstr (mc_shell->path, "/ksh") != NULL
+             || strstr (mc_shell->real_path, "/ksh") != NULL
+             || strstr (mc_shell->path, "/oksh") != NULL
+             || strstr (mc_shell->real_path, "/oksh") != NULL)
+    {
+        mc_shell->type = SHELL_KSH;
+        mc_shell->name = "ksh";
+    }
+    else if (strstr (mc_shell->path, "/mksh") != NULL
+             || strstr (mc_shell->real_path, "/mksh") != NULL)
+    {
+        mc_shell->type = SHELL_MKSH;
+        mc_shell->name = "mksh";
+    }
     else
         mc_shell->type = SHELL_NONE;
 }
@@ -199,21 +219,34 @@ static void
 mc_shell_recognize_path (mc_shell_t *mc_shell)
 {
     /* If shell is not symlinked to busybox, it is safe to assume it is a real shell */
-    if (strstr (mc_shell->path, "/bash") != NULL || getenv ("BASH") != NULL)
+    if (strstr (mc_shell->path, "/bash") != NULL || getenv ("BASH_VERSION") != NULL)
     {
         mc_shell->type = SHELL_BASH;
         mc_shell->name = "bash";
     }
-    else if (strstr (mc_shell->path, "/sh") != NULL || getenv ("SH") != NULL)
+    else if (strstr (mc_shell->path, "/sh") != NULL)
     {
         mc_shell->type = SHELL_SH;
         mc_shell->name = "sh";
     }
-    else if (strstr (mc_shell->path, "/ash") != NULL || getenv ("ASH") != NULL)
+    else if (strstr (mc_shell->path, "/ash") != NULL || getenv ("BB_ASH_VERSION") != NULL)
     {
         mc_shell->type = SHELL_ASH_BUSYBOX;
         mc_shell->name = "ash";
     }
+    else if (strstr (mc_shell->path, "/ksh") != NULL
+             || strstr (mc_shell->path, "/oksh") != NULL
+             || (getenv ("KSH_VERSION") != NULL && strstr (getenv ("KSH_VERSION"), "PD KSH") != NULL))
+    {
+        mc_shell->type = SHELL_KSH;
+        mc_shell->name = "ksh";
+    }
+    else if (strstr (mc_shell->path, "/mksh") != NULL
+             || (getenv ("KSH_VERSION") != NULL && strstr (getenv ("KSH_VERSION"), "MIRBSD KSH") != NULL))
+    {
+        mc_shell->type = SHELL_MKSH;
+        mc_shell->name = "mksh";
+    }
     else
         mc_shell->type = SHELL_NONE;
 }

lib/shell.h

@@ -18,7 +18,9 @@ typedef enum
     SHELL_DASH,                 /* Debian variant of ash */
     SHELL_TCSH,
     SHELL_ZSH,
-    SHELL_FISH
+    SHELL_FISH,
+    SHELL_KSH,                  /* Public Domain Korn shell (pdksh) and variants */
+    SHELL_MKSH                  /* MirBSD Korn shell (mksh) */
 } shell_type_t;
 
 /*** structures declarations (and typedefs of structures)*****************************************/

src/subshell/common.c

@@ -366,6 +366,45 @@ init_subshell_child (const char *pty_name)
 
         break;
 
+    case SHELL_KSH:
+        /* Do we have a custom init file ~/.local/share/mc/kshrc? */
+        init_file = mc_config_get_full_path (MC_KSHRC_FILE);
+
+        /* Otherwise use ~/.profile */
+        if (!exist_file (init_file))
+        {
+            g_free (init_file);
+            init_file = g_strdup (".profile");
+        }
+
+        /* Put init file to ENV variable used by ksh but only if it
+         * is not already set. */
+        g_setenv ("ENV", init_file, FALSE);
+
+        /* Make MC's special commands not show up in history */
+        putenv ((char *) "HISTCONTROL=ignorespace");
+
+        break;
+
+    case SHELL_MKSH:
+        /* Do we have a custom init file ~/.local/share/mc/mkshrc? */
+        init_file = mc_config_get_full_path (MC_MKSHRC_FILE);
+
+        /* Otherwise use ~/.mkshrc (default behavior of mksh) */
+        if (!exist_file (init_file))
+        {
+            g_free (init_file);
+            init_file = g_strdup (".mkshrc");
+        }
+
+        /* Put init file to ENV variable used by mksh but only if it
+         * is not already set. */
+        g_setenv ("ENV", init_file, FALSE);
+
+        /* Note mksh doesn't support HISTCONTROL. */
+
+        break;
+
     case SHELL_ZSH:
         /* ZDOTDIR environment variable is the only way to point zsh
          * to an other rc file than the default. */
@@ -439,6 +478,8 @@ init_subshell_child (const char *pty_name)
     case SHELL_ASH_BUSYBOX:
     case SHELL_DASH:
     case SHELL_TCSH:
+    case SHELL_KSH:
+    case SHELL_MKSH:
         execl (mc_global.shell->path, mc_global.shell->path, (char *) NULL);
         break;
 
@@ -1093,6 +1134,39 @@ pty_open_slave (const char *pty_name)
 static void
 init_subshell_precmd (char *precmd, size_t buff_size)
 {
+    /* Attention! Make sure that the buffer for precmd is big enough. */
+
+    /* Fallback precmd emulation that should work with virtually any shell.
+     * No real precmd functionality is required, no support for \x substitutions
+     * in PS1 is needed. For convenience, $HOME is replaced by ~ in PS1.
+     *
+     * The following example is a little less fancy (home directory not replaced)
+     * and shows the basic workings of our prompt for easier understanding:
+     *
+     * "precmd() { "
+     *     "echo \"$USER@$(hostname -s):$PWD\"; "
+     *     "pwd>&%d; "
+     *     "kill -STOP $$; "
+     * "}; "
+     * "PRECMD=precmd; "
+     * "PS1='$($PRECMD)$ '\n",
+     */
+    static const char *precmd_fallback =
+        " "  /* Useful if the shell supports HISTCONTROL=ignorespace like functionality */
+        "MC_PS1_SAVED=\"$PS1\"; "  /* Save custom PS1 */
+        "precmd() { "
+            "if [ ! \"${PWD##$HOME}\" ]; then "
+                "MC_PWD=\"~\"; "
+            "else "
+                "[ \"${PWD##$HOME/}\" = \"$PWD\" ] && MC_PWD=\"$PWD\" || MC_PWD=\"~/${PWD##$HOME/}\"; "
+            "fi; "
+            "echo \"${MC_PS1_SAVED:-$USER@$(hostname -s):$MC_PWD\\$ }\"; "
+            "pwd>&%d; "
+            "kill -STOP $$; "
+        "}; "
+        "PRECMD=precmd; "
+        "PS1='$($PRECMD)'\n";
+
     switch (mc_global.shell->type)
     {
     case SHELL_BASH:
@@ -1126,44 +1200,31 @@ init_subshell_precmd (char *precmd, size_t buff_size)
          *    Attention: BusyBox must be built with FEATURE_EDITING_FANCY_PROMPT to
          *    permit \u, \w, \h, \$ escape sequences. Unfortunately this cannot be guaranteed,
          *    especially on embedded systems where people try to save space, so let's use
-         *    the dash version below. It should work on virtually all systems.
-         *    "precmd() { pwd>&%d; kill -STOP $$; }; "
-         *    "PRECMD=precmd; "
-         *    "PS1='$(eval $PRECMD)\\u@\\h:\\w\\$ '\n",
+         *    the falback version.
          */
+        g_snprintf (precmd, buff_size, precmd_fallback, subshell_pipe[WRITE]);
+        break;
+
     case SHELL_DASH:
         /* Debian ash needs a precmd emulation via PS1, similar to BusyBox ash,
          * but does not support escape sequences for user, host and cwd in prompt.
-         * Attention! Make sure that the buffer for precmd is big enough.
-         *
-         * We want to have a fancy dynamic prompt with user@host:cwd just like in the BusyBox
-         * examples above, but because replacing the home directory part of the path by "~" is
-         * complicated, it bloats the precmd to a size > BUF_SMALL (128).
-         *
-         * The following example is a little less fancy (home directory not replaced)
-         * and shows the basic workings of our prompt for easier understanding:
-         *
-         * "precmd() { "
-         *     "echo \"$USER@$(hostname -s):$PWD\"; "
-         *     "pwd>&%d; "
-         *     "kill -STOP $$; "
-         * "}; "
-         * "PRECMD=precmd; "
-         * "PS1='$($PRECMD)$ '\n",
          */
-        g_snprintf (precmd, buff_size,
-                    "precmd() { "
-                    "if [ ! \"${PWD##$HOME}\" ]; then "
-                    "MC_PWD=\"~\"; "
-                    "else "
-                    "[ \"${PWD##$HOME/}\" = \"$PWD\" ] && MC_PWD=\"$PWD\" || MC_PWD=\"~/${PWD##$HOME/}\"; "
-                    "fi; "
-                    "echo \"$USER@$(hostname -s):$MC_PWD\"; "
-                    "pwd>&%d; "
-                    "kill -STOP $$; "
-                    "}; " "PRECMD=precmd; " "PS1='$($PRECMD)$ '\n", subshell_pipe[WRITE]);
+        g_snprintf (precmd, buff_size, precmd_fallback, subshell_pipe[WRITE]);
         break;
 
+    case SHELL_MKSH:
+        /* mksh doesn't support \x placeholders in PS1 and needs precmd emulation via PS1 */
+        g_snprintf (precmd, buff_size, precmd_fallback, subshell_pipe[WRITE]);
+        break;
+
+    case SHELL_KSH:
+        /* pdksh based variants support \x placeholders but not any "precmd" functionality. */
+        g_snprintf (precmd, buff_size,
+                    " PS1='$(pwd>&%d; kill -STOP $$)'"
+                    "\"${PS1:-\\u@\\h:\\w\\$ }\"\n",
+                    subshell_pipe[WRITE]);
+       break;
+
     case SHELL_ZSH:
         g_snprintf (precmd, buff_size,
                     " mc_print_command_buffer () { printf \"%%s\\\\n\" \"$BUFFER\" >&%d; }\n"
@@ -1209,11 +1270,11 @@ init_subshell_precmd (char *precmd, size_t buff_size)
  * Use following technique:
  *
  * printf(1) with format string containing a single conversion specifier,
- * "b", and an argument which contains a copy of the string passed to 
+ * "b", and an argument which contains a copy of the string passed to
  * subshell_name_quote() with all characters, except digits and letters,
  * replaced by the backslash-escape sequence \0nnn, where "nnn" is the
  * numeric value of the character converted to octal number.
- * 
+ *
  *   cd "`printf '%b' 'ABC\0nnnDEF\0nnnXYZ'`"
  *
  * N.B.: Use single quotes for conversion specifier to work around