Strange behaviour of 'exit' command

Strange behaviour of 'exit' command

[Ian Abbott]

I noticed some strange behaviour in the 'hush' shell when the 'sh' and 
'exit' commands are used:

---------------------------------
barebox:/ sh
barebox:/ exit
t: No such file or directory
barebox:/ echo $?
127
barebox:/
---------------------------------

Also:

---------------------------------
barebox:/ sh
barebox:/ exit 2

sh - execute a shell script

Usage: sh FILE [ARGUMENT...]

t: No such file or directory
barebox:/
---------------------------------

Can anyone else reproduce this?

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Re: Strange behaviour of 'exit' command

[Sascha Hauer]

Hi Ian,

On Wed, Jun 12, 2019 at 11:42:24AM +0100, Ian Abbott wrote:
> I noticed some strange behaviour in the 'hush' shell when the 'sh' and
> 'exit' commands are used:
> 
> ---------------------------------
> barebox:/ sh
> barebox:/ exit
> t: No such file or directory
> barebox:/ echo $?
> 127
> barebox:/
> ---------------------------------

After some digging:

in common/hush.c get_user_input() we have:

	static char the_command[CONFIG_CBSIZE];

This string is used for user input and is unfortunately shared between
different shell instances. The 't' that is executed is the 't' from
'exit'. Try ' exit' instead and you'll see the shell trying to execute
'it' ;)

the_command should be dynamically allocated, but since in_str is
currently statically allocated there is no place in the code to free
the_command again after usage.

Sascha

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