From b64512b750351d83691c02e5bf118d3e00dae85f Mon Sep 17 00:00:00 2001
From: d3m3t3r <46783027+d3m3t3r@users.noreply.github.com>
Date: Thu, 7 Nov 2024 13:42:56 +0000
Subject: [PATCH 1/8] Ticket #3748: add support for ksh in subshell

Support Korn shell variants (ksh/oksh/mksh) in the subshell.
---
 doc/man/mc.1.in       |  4 ++++
 lib/fileloc.h         |  1 +
 lib/mcconfig/paths.c  |  1 +
 lib/shell.c           | 21 +++++++++++++++++++++
 lib/shell.h           |  3 ++-
 src/subshell/common.c | 34 ++++++++++++++++++++++++++++++++++
 6 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/doc/man/mc.1.in b/doc/man/mc.1.in
index aebc9ba1f0..e0ac3cfefe 100644
--- a/doc/man/mc.1.in
+++ b/doc/man/mc.1.in
@@ -2406,6 +2406,10 @@ 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
+users (ksh, oksh or mksh) may specify startup commands in ~/.local/share/mc/kshrc
+(fallback $ENV or ~/.profile).
+.PP
 .B zsh
 users may specify startup commands in ~/.local/share/mc/.zshrc (fallback ~/.zshrc).
 .PP
diff --git a/lib/fileloc.h b/lib/fileloc.h
index a075d030f9..fe40a0fdce 100644
--- a/lib/fileloc.h
+++ b/lib/fileloc.h
@@ -53,6 +53,7 @@
 #define MC_BASHRC_FILE          "bashrc"
 #define MC_ZSHRC_FILE           ".zshrc"
 #define MC_ASHRC_FILE           "ashrc"
+#define MC_KSHRC_FILE           "kshrc"
 #define MC_INPUTRC_FILE         "inputrc"
 #define MC_CONFIG_FILE          "ini"
 #define MC_EXT_FILE             "mc.ext.ini"
diff --git a/lib/mcconfig/paths.c b/lib/mcconfig/paths.c
index 1baca54b8e..79309d0c17 100644
--- a/lib/mcconfig/paths.c
+++ b/lib/mcconfig/paths.c
@@ -75,6 +75,7 @@ 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_BASHRC_FILE },
     { &mc_data_str, MC_INPUTRC_FILE },
     { &mc_data_str, MC_ZSHRC_FILE },
diff --git a/lib/shell.c b/lib/shell.c
index 730ded43ce..e018d17c08 100644
--- a/lib/shell.c
+++ b/lib/shell.c
@@ -80,6 +80,8 @@ 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");
     /* 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 +191,17 @@ 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
+             || strstr (mc_shell->path, "/mksh") != NULL
+             || strstr (mc_shell->real_path, "/mksh") != NULL)
+    {
+        /* Korn shell variants */
+        mc_shell->type = SHELL_KSH;
+        mc_shell->name = "ksh";
+    }
     else
         mc_shell->type = SHELL_NONE;
 }
@@ -214,6 +227,14 @@ mc_shell_recognize_path (mc_shell_t *mc_shell)
         mc_shell->type = SHELL_ASH_BUSYBOX;
         mc_shell->name = "ash";
     }
+    else if (strstr (mc_shell->path, "/ksh") != NULL 
+             || strstr (mc_shell->path, "/oksh") != NULL
+             || strstr (mc_shell->path, "/mksh") != NULL
+             || getenv ("KSH_VERSION") != NULL)
+    {
+        mc_shell->type = SHELL_KSH;
+        mc_shell->name = "ksh";
+    }
     else
         mc_shell->type = SHELL_NONE;
 }
diff --git a/lib/shell.h b/lib/shell.h
index 7ba82dc078..e2b733b91a 100644
--- a/lib/shell.h
+++ b/lib/shell.h
@@ -18,7 +18,8 @@ typedef enum
     SHELL_DASH,                 /* Debian variant of ash */
     SHELL_TCSH,
     SHELL_ZSH,
-    SHELL_FISH
+    SHELL_FISH,
+    SHELL_KSH
 } shell_type_t;
 
 /*** structures declarations (and typedefs of structures)*****************************************/
diff --git a/src/subshell/common.c b/src/subshell/common.c
index 69b1f30e4e..842d16fdef 100644
--- a/src/subshell/common.c
+++ b/src/subshell/common.c
@@ -366,6 +366,33 @@ 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 $ENV is not already set */
+        if (!exist_file (init_file))
+        {
+            g_free (init_file);
+            init_file = NULL;
+
+            if (!g_getenv ("ENV"))
+            {
+                init_file = g_strdup (".profile");
+            }
+        }
+
+        /* Put init file to ENV variable used by ash */
+        if (init_file)
+        {
+            g_setenv ("ENV", init_file, TRUE);
+        }
+
+        /* Make MC's special commands not show up in history */
+        putenv ((char *) "HISTCONTROL=ignorespace");
+
+        break;
+
     case SHELL_ZSH:
         /* ZDOTDIR environment variable is the only way to point zsh
          * to an other rc file than the default. */
@@ -439,6 +466,7 @@ init_subshell_child (const char *pty_name)
     case SHELL_ASH_BUSYBOX:
     case SHELL_DASH:
     case SHELL_TCSH:
+    case SHELL_KSH:
         execl (mc_global.shell->path, mc_global.shell->path, (char *) NULL);
         break;
 
@@ -1164,6 +1192,12 @@ init_subshell_precmd (char *precmd, size_t buff_size)
                     "}; " "PRECMD=precmd; " "PS1='$($PRECMD)$ '\n", subshell_pipe[WRITE]);
         break;
 
+    case SHELL_KSH:
+        g_snprintf (precmd, buff_size,
+                    " PS1='$(pwd>&%d; kill -STOP $$)\\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"

From bd1e68b66ac19bf8ae77cbe6896a500e5ffc4fed Mon Sep 17 00:00:00 2001
From: d3m3t3r <46783027+d3m3t3r@users.noreply.github.com>
Date: Thu, 7 Nov 2024 16:38:23 +0000
Subject: [PATCH 2/8] Simplify setting ENV variable without overriding it

---
 src/subshell/common.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/src/subshell/common.c b/src/subshell/common.c
index 842d16fdef..5d1dd20df8 100644
--- a/src/subshell/common.c
+++ b/src/subshell/common.c
@@ -370,23 +370,16 @@ init_subshell_child (const char *pty_name)
         /* 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 $ENV is not already set */
+        /* Otherwise use ~/.profile */
         if (!exist_file (init_file))
         {
             g_free (init_file);
-            init_file = NULL;
-
-            if (!g_getenv ("ENV"))
-            {
-                init_file = g_strdup (".profile");
-            }
+            init_file = g_strdup (".profile");
         }
 
-        /* Put init file to ENV variable used by ash */
-        if (init_file)
-        {
-            g_setenv ("ENV", init_file, TRUE);
-        }
+        /* 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");

From 139917c37ef51f22c4c309d52231e04d773f022f Mon Sep 17 00:00:00 2001
From: d3m3t3r <46783027+d3m3t3r@users.noreply.github.com>
Date: Thu, 7 Nov 2024 21:37:24 +0000
Subject: [PATCH 3/8] Fix support for mksh

mksh (MirBSD Korn shell) is handled separately as it substantially
differs from pdksh (Public Domain Korn shell) based varaints.
---
 doc/man/mc.1.in       |  8 ++++++--
 lib/fileloc.h         |  1 +
 lib/mcconfig/paths.c  |  1 +
 lib/shell.c           | 26 +++++++++++++++++++-------
 lib/shell.h           |  3 ++-
 src/subshell/common.c | 24 ++++++++++++++++++++++++
 6 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/doc/man/mc.1.in b/doc/man/mc.1.in
index e0ac3cfefe..8d8d6c6b69 100644
--- a/doc/man/mc.1.in
+++ b/doc/man/mc.1.in
@@ -2406,10 +2406,14 @@ 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
-users (ksh, oksh or mksh) may specify startup commands in ~/.local/share/mc/kshrc
+.B ksh/oksh
+users (PD ksh variants) may specify startup commands in ~/.local/share/mc/kshrc
 (fallback $ENV or ~/.profile).
 .PP
+.B mksh
+users (MirBSD ksh) may specify startup commands in ~/.local/share/mc/mkshrc
+(fallback $ENV or ~/.mkshrc).
+.PP
 .B zsh
 users may specify startup commands in ~/.local/share/mc/.zshrc (fallback ~/.zshrc).
 .PP
diff --git a/lib/fileloc.h b/lib/fileloc.h
index fe40a0fdce..fad3181bcb 100644
--- a/lib/fileloc.h
+++ b/lib/fileloc.h
@@ -54,6 +54,7 @@
 #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"
diff --git a/lib/mcconfig/paths.c b/lib/mcconfig/paths.c
index 79309d0c17..f33ea99330 100644
--- a/lib/mcconfig/paths.c
+++ b/lib/mcconfig/paths.c
@@ -76,6 +76,7 @@ static const struct
     { &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 },
diff --git a/lib/shell.c b/lib/shell.c
index e018d17c08..9560684f93 100644
--- a/lib/shell.c
+++ b/lib/shell.c
@@ -82,6 +82,10 @@ mc_shell_get_installed_in_system (void)
         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
@@ -194,14 +198,17 @@ mc_shell_recognize_real_path (mc_shell_t *mc_shell)
     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
-             || strstr (mc_shell->path, "/mksh") != NULL
-             || strstr (mc_shell->real_path, "/mksh") != NULL)
+             || strstr (mc_shell->real_path, "/oksh") != NULL)
     {
-        /* Korn shell variants */
         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;
 }
@@ -227,14 +234,19 @@ mc_shell_recognize_path (mc_shell_t *mc_shell)
         mc_shell->type = SHELL_ASH_BUSYBOX;
         mc_shell->name = "ash";
     }
-    else if (strstr (mc_shell->path, "/ksh") != NULL 
+    else if (strstr (mc_shell->path, "/ksh") != NULL
              || strstr (mc_shell->path, "/oksh") != NULL
-             || strstr (mc_shell->path, "/mksh") != NULL
-             || getenv ("KSH_VERSION") != 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;
 }
diff --git a/lib/shell.h b/lib/shell.h
index e2b733b91a..bf5ada3adc 100644
--- a/lib/shell.h
+++ b/lib/shell.h
@@ -19,7 +19,8 @@ typedef enum
     SHELL_TCSH,
     SHELL_ZSH,
     SHELL_FISH,
-    SHELL_KSH
+    SHELL_KSH,                  /* Public Domain Korn shell (pdksh) and variants */
+    SHELL_MKSH                  /* MirBSD Korn shell (mksh) */
 } shell_type_t;
 
 /*** structures declarations (and typedefs of structures)*****************************************/
diff --git a/src/subshell/common.c b/src/subshell/common.c
index 5d1dd20df8..18d7a0849b 100644
--- a/src/subshell/common.c
+++ b/src/subshell/common.c
@@ -386,6 +386,23 @@ init_subshell_child (const char *pty_name)
 
         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 */
+        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);
+
+        break;
+
     case SHELL_ZSH:
         /* ZDOTDIR environment variable is the only way to point zsh
          * to an other rc file than the default. */
@@ -460,6 +477,7 @@ init_subshell_child (const char *pty_name)
     case SHELL_DASH:
     case SHELL_TCSH:
     case SHELL_KSH:
+    case SHELL_MKSH:
         execl (mc_global.shell->path, mc_global.shell->path, (char *) NULL);
         break;
 
@@ -1191,6 +1209,12 @@ init_subshell_precmd (char *precmd, size_t buff_size)
                     subshell_pipe[WRITE]);
        break;
 
+    case SHELL_MKSH:
+        g_snprintf (precmd, buff_size,
+                    " PS1='$(pwd>&%d; kill -STOP $$)${USER:=$(id -un)}@${HOSTNAME:=$(hostname -s)}:$PWD\\$ '\n",
+                    subshell_pipe[WRITE]);
+       break;
+
     case SHELL_ZSH:
         g_snprintf (precmd, buff_size,
                     " mc_print_command_buffer () { printf \"%%s\\\\n\" \"$BUFFER\" >&%d; }\n"

From 1df53a785ee7997f0467f3d3ca1dc5b90ac3e993 Mon Sep 17 00:00:00 2001
From: d3m3t3r <46783027+d3m3t3r@users.noreply.github.com>
Date: Thu, 7 Nov 2024 22:32:58 +0000
Subject: [PATCH 4/8] Add comments explaining pdksh and mksh features

---
 src/subshell/common.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/subshell/common.c b/src/subshell/common.c
index 18d7a0849b..857c842f49 100644
--- a/src/subshell/common.c
+++ b/src/subshell/common.c
@@ -390,7 +390,7 @@ init_subshell_child (const char *pty_name)
         /* Do we have a custom init file ~/.local/share/mc/mkshrc? */
         init_file = mc_config_get_full_path (MC_MKSHRC_FILE);
 
-        /* Otherwise use ~/.mkshrc */
+        /* Otherwise use ~/.mkshrc (default behavior of mksh) */
         if (!exist_file (init_file))
         {
             g_free (init_file);
@@ -401,6 +401,8 @@ init_subshell_child (const char *pty_name)
          * is not already set. */
         g_setenv ("ENV", init_file, FALSE);
 
+        /* Note mksh doesn't support HISTCONTROL. */
+
         break;
 
     case SHELL_ZSH:
@@ -1204,12 +1206,14 @@ init_subshell_precmd (char *precmd, size_t buff_size)
         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 $$)\\u@\\h:\\w\\$ '\n",
                     subshell_pipe[WRITE]);
        break;
 
     case SHELL_MKSH:
+        /* mksh doesn't support \x placeholders neither any "precmd" functionality */
         g_snprintf (precmd, buff_size,
                     " PS1='$(pwd>&%d; kill -STOP $$)${USER:=$(id -un)}@${HOSTNAME:=$(hostname -s)}:$PWD\\$ '\n",
                     subshell_pipe[WRITE]);

From dcc71b590341059b0d6cc5ed284ca96dc1f7c2a1 Mon Sep 17 00:00:00 2001
From: d3m3t3r <46783027+d3m3t3r@users.noreply.github.com>
Date: Wed, 20 Nov 2024 22:43:15 +0000
Subject: [PATCH 5/8] Simplify fallback precmd emulation

---
 src/subshell/common.c | 87 +++++++++++++++++++++++--------------------
 1 file changed, 46 insertions(+), 41 deletions(-)

diff --git a/src/subshell/common.c b/src/subshell/common.c
index 857c842f49..407fa5d9bb 100644
--- a/src/subshell/common.c
+++ b/src/subshell/common.c
@@ -1134,6 +1134,38 @@ 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 $$; "
+     * "}; "
+     * "PRECMD=precmd; "
+     * "PS1='$($PRECMD)$ '\n",
+     */
+    static const char *precmd_fallback =
+        " "  /* Useful if the shell supports HISTCONTROL=ignorespace like functionality */
+        "precmd() { "
+            "if [ ! \"${PWD##$HOME}\" ]; then "
+                "MC_PWD=\"~\"; "
+            "else "
+                "[ \"${PWD##$HOME/}\" = \"$PWD\" ] && MC_PWD=\"$PWD\" || MC_PWD=\"~/${PWD##$HOME/}\"; "
+            "fi; "
+            "echo \"$USER@$(hostname -s):$MC_PWD\"; "
+            "pwd>&%d; "
+            "kill -STOP $$; "
+        "}; "
+        "PRECMD=precmd; "
+        "PS1='$($PRECMD)$ '\n";
+
     switch (mc_global.shell->type)
     {
     case SHELL_BASH:
@@ -1167,55 +1199,28 @@ 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 $$)\\u@\\h:\\w\\$ '\n",
-                    subshell_pipe[WRITE]);
-       break;
-
-    case SHELL_MKSH:
-        /* mksh doesn't support \x placeholders neither any "precmd" functionality */
-        g_snprintf (precmd, buff_size,
-                    " PS1='$(pwd>&%d; kill -STOP $$)${USER:=$(id -un)}@${HOSTNAME:=$(hostname -s)}:$PWD\\$ '\n",
+                    " PS1='$(pwd>&%d; kill -STOP $$)'"
+                    "\"${PS1:-\\u@\\h:\\w\\$ }\"\n",
                     subshell_pipe[WRITE]);
        break;
 
@@ -1264,11 +1269,11 @@ 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

From 9d4bbe5ee0b22b80061c27631b4945eb80e2ce61 Mon Sep 17 00:00:00 2001
From: d3m3t3r <46783027+d3m3t3r@users.noreply.github.com>
Date: Tue, 26 Nov 2024 18:59:24 +0000
Subject: [PATCH 6/8] Support user prompt in fallback precmd emulation

---
 src/subshell/common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/subshell/common.c b/src/subshell/common.c
index 407fa5d9bb..7beeebc8b3 100644
--- a/src/subshell/common.c
+++ b/src/subshell/common.c
@@ -1153,18 +1153,19 @@ init_subshell_precmd (char *precmd, size_t buff_size)
      */
     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##$HOME/}\"; "
             "fi; "
-            "echo \"$USER@$(hostname -s):$MC_PWD\"; "
+            "echo \"${MC_PS1_SAVED:-$USER@$(hostname -s):$MC_PWD\\$ }\"; "
             "pwd>&%d; "
             "kill -STOP $$; "
         "}; "
         "PRECMD=precmd; "
-        "PS1='$($PRECMD)$ '\n";
+        "PS1='$($PRECMD)'\n";
 
     switch (mc_global.shell->type)
     {

From 8eaa50dd25ec5bb7cc7e2c594356d57306af9601 Mon Sep 17 00:00:00 2001
From: "Yury V. Zaytsev" <yury@shurup.com>
Date: Sun, 12 Jan 2025 19:16:33 +0100
Subject: [PATCH 7/8] fixup! Ticket #3748: add support for ksh in subshell

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>
---
 doc/man/mc.1.in | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/doc/man/mc.1.in b/doc/man/mc.1.in
index 8d8d6c6b69..b408b2a26f 100644
--- a/doc/man/mc.1.in
+++ b/doc/man/mc.1.in
@@ -2408,11 +2408,15 @@ users (BusyBox or Debian) may specify startup commands in ~/.local/share/mc/ashr
 .PP
 .B ksh/oksh
 users (PD ksh variants) may specify startup commands in ~/.local/share/mc/kshrc
-(fallback $ENV or ~/.profile).
+(fallback
+.I ENV
+or ~/.profile).
 .PP
 .B mksh
 users (MirBSD ksh) may specify startup commands in ~/.local/share/mc/mkshrc
-(fallback $ENV or ~/.mkshrc).
+(fallback
+.I ENV
+or ~/.mkshrc).
 .PP
 .B zsh
 users may specify startup commands in ~/.local/share/mc/.zshrc (fallback ~/.zshrc).

From b07a6f24592f38b777ec25cbc5b4f96dcba75bfc Mon Sep 17 00:00:00 2001
From: "Yury V. Zaytsev" <yury@shurup.com>
Date: Sun, 12 Jan 2025 19:49:48 +0100
Subject: [PATCH 8/8] subshell: fix environment variable names in
 `mc_shell_recognize_path`

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>
---
 lib/shell.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/shell.c b/lib/shell.c
index 9560684f93..72411c8a58 100644
--- a/lib/shell.c
+++ b/lib/shell.c
@@ -219,17 +219,17 @@ 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";