Support plain POSIX /bin/sh (Bourne shell) as subshell

[slyfox]

Many environments provide POSIX compliant /bin/sh shell symlinking to:

• busybox: ash, hush
• debian: dash

(passwd entry usually contains /bin/sh for them)

• They are mostly supported via symlink resolution (see #2742)
• Maybe even better support is possible by interacting with shell (see #3692)

Some systems provide "real" plain Bourne shell, like FreeBSD or Solaris.

These shells are not supported at the moment. Whether support is possible at all with some sort of precmd emulation via PS1 tricks is to be investigated.

The current state of the art is that due to missing variable expansion it's not possible. Please reopen if you have new research and/or patches.

[andrew_b]

Ticket #3658 has been marked as a duplicate of this ticket.

[sorin]

This bug is still valid and prevents use of mc on lost of system. Another entire set is FreeBSD and pfSense where starting mc works only with "mc -u" which is real PITA.

At least this fatal error should be converted into a warning that does not prevent the app from starting.

[enerccio]

again 11 years and no fix :x still present on many embedded devices that use busybox shell

[Snelius]

Fix patch

[Snelius]

I've added the patch to fix this misbehaviour. It disables a subshell to allow mc start.
This patch against master branch.
GH PR: ​https://github.com/MidnightCommander/mc/pull/183

[zaytsev]

From e2d7ee06bc32c40f119372d15df362913efbcbfd Mon Sep 17 00:00:00 2001
From: Anatoly Y <anatoly@box64.top>
Date: Thu, 13 Apr 2023 22:24:16 +0700
Subject: [PATCH] Workaround. Fix. #373

---
 src/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.c b/src/main.c
index c18e069c68..3564876d07 100644
--- a/src/main.c
+++ b/src/main.c
@@ -362,7 +362,7 @@ main (int argc, char *argv[])
 
 #ifdef ENABLE_SUBSHELL
     /* Disallow subshell when invoked as standalone viewer or editor from running mc */
-    if (mc_global.mc_run_mode != MC_RUN_FULL && mc_global.run_from_parent_mc)
+    if (mc_global.shell->type == SHELL_SH || (mc_global.mc_run_mode != MC_RUN_FULL && mc_global.run_from_parent_mc))
         mc_global.tty.use_subshell = FALSE;
 
     if (mc_global.tty.use_subshell)

[andrew_b]

Ticket #4531 has been marked as a duplicate of this ticket.

[zaytsev]

Closed as duplicate of #3692.