[PATCH] shell: Fixing bug in line editing of the shell with CTRL-U.

[Chris Johns]

On 26/9/20 2:06 am, Joel Sherrill wrote:
> On Fri, Sep 25, 2020, 10:06 AM Gedare Bloom <gedare at rtems.org
> <mailto:gedare at rtems.org>> wrote:
> 
>     On Fri, Sep 25, 2020 at 3:11 AM Frank Kuehndel
>     <frank.kuehndel at embedded-brains.de
>     <mailto:frank.kuehndel at embedded-brains.de>> wrote:
>     >
>     > This patch fixes a tiny bug in the command line editing of the RTEMS
>     shell. Typing CTRL-U in the shell should remove all characters left of the
>     cursor. After pressing CTRL-U, the current implementation does wrongly place
>     the cursor at the end of the line instead at its beginning.
>     >
>     >
>     > To reproduce the bug, start the shell and type 'abc123' (no <RETURN>):
>     >
>     > > ~/src/rtems $ qemu-system-arm -net none -nographic -M realview-pbx-a9 -m
>     256M -kernel build/arm/realview_pbx_a9_qemu/testsuites/libtests/dl10.exe
>     > >
>     > >
>     > > *** BEGIN OF TEST libdl (RTL) 10 ***
>     > > *** TEST VERSION: 6.0.0.d9bdf166644f612dd628fe4951c12c6f8e94ba5f
>     > > *** TEST STATE: USER_INPUT
>     > > *** TEST BUILD: RTEMS_DEBUG RTEMS_NETWORKING RTEMS_POSIX_API RTEMS_SMP
>     > > *** TEST TOOLS: 10.2.1 20200904 (RTEMS 6, RSB
>     31f936a7b74d60bda609a9960c6e1a705ba54974, Newlib a0d7982)
>     > > RTL (libdl) commands: dl, rtl
>     > >
>     > >
>     > > RTEMS Shell on /dev/foobar. Use 'help' to list commands.
>     > > SHLL [/] # abc123
>     >
>     > Then move the cursor onto the '1' by hitting three times the <ARROW-LEFT>
>     key. Next type <CTRL>-U:
>     >
>     > > SHLL [/] # 123
>     >
>     > Note that the cursor is at the end of the line (after '3') instead of
>     correctly at the beginning (on the '1'), now.
>     >
>     > Continuing typing 'echo ' incorrectly results in the output:
>     >
>     > > SHLL [/] # 123echo 123
>     >
>     > The patch changes this behavior so that the cursor in the second last step
>     will be on the '1' and typing 'echo ' will then correctly reflected as:
>     >
>     > > SHLL [/] # echo 123
>     >
> 
>     Please put the above bug details into a ticket
>     https://devel.rtems.org/wiki/NewTicket with a milestone of 6
> 
> 
> Why wouldn't this also be appropriate for 5?
> 

It is fine for 5 with a ticket.

> And can anyone confirm this happens on real hardware? Sometimes control
> characters act funny on simulators.

It is broken on hardware so the simulator and hardware match.

Chris