[SOLVED] Grub shell does not work like a shell at all

maxkukartsev · 07-22-2009, 05:33 PM

Hello all,

The problem I'm having is referred to as "broken grub tab completion". Looking for solutions I've come across a lot of complaints about this but no solutions.

I am using Fedora 11, and have experienced this problem on Fedora 10 as well.

I am referring to GRUB launched from an interactive login shell, not in its native environment when it boots up.

I open the GNOME Terminal (bash)
Launch grub
Press [TAB] - A list of commands should display but does not, the cursor simply goes left
Type root (hd0,0)
Press [UP] - GRUB should return me to the previous command "root (hd0,0)" but does not, instead it types "^[[A", apparently the literal interpretation of the [UP] key

So here is the general problem. GRUB is supposed to act like a shell and handle the [TAB] completion and [UP]/[DOWN] keystrokes properly, but does not, and handles them LITERALLY.

On Ubuntu, this is not a problem. GRUB works as expected.

What is going on?

Thanks for your help.

pixellany · 07-22-2009, 05:54 PM

Here's what GRUB tells me when I start it:

Code:

GNU GRUB  version 0.97  (640K lower / 3072K upper memory)

 [ Minimal BASH-like line editing is supported.  For the first word, TAB
   lists possible command completions.  Anywhere else TAB lists the possible
   completions of a device/filename. ]

grub>

What does Fedora give you?

linus72 · 07-22-2009, 05:59 PM

Here is my grub prompt in new fed11 lxde
as user
and as root

Code:

[bz@Fedora-11 ~]$ grub
Probing devices to guess BIOS drives. This may take a long time.


    GNU GRUB  version 0.97  (640K lower / 3072K upper memory)

 [ Minimal BASH-like line editing is supported.  For the first word, TAB
   lists possible command completions.  Anywhere else TAB lists the possible
   completions of a device/filename.]
grub> quit
quit
[bz@Fedora-11 ~]$ su
Password: 
su: incorrect password
[bz@Fedora-11 ~]$ su
Password: 
[root@Fedora-11 bz]# grub
Probing devices to guess BIOS drives. This may take a long time.


    GNU GRUB  version 0.97  (640K lower / 3072K upper memory)

 [ Minimal BASH-like line editing is supported.  For the first word, TAB
   lists possible command completions.  Anywhere else TAB lists the possible
   completions of a device/filename.]
grub>

maxkukartsev · 07-22-2009, 07:04 PM

Thanks for the quick reply.

GRUB on Fedora displays the same text as you posted:

Code:

[liveuser@localhost ~]$ grub
Probing devices to guess BIOS drives. This may take a long time.


    GNU GRUB  version 0.97  (640K lower / 3072K upper memory)

 [ Minimal BASH-like line editing is supported.  For the first word, TAB
   lists possible command completions.  Anywhere else TAB lists the possible
   completions of a device/filename.]
grub> quit
quit
[liveuser@localhost ~]$ su
[root@localhost liveuser]# grub
Probing devices to guess BIOS drives. This may take a long time.


    GNU GRUB  version 0.97  (640K lower / 3072K upper memory)

 [ Minimal BASH-like line editing is supported.  For the first word, TAB
   lists possible command completions.  Anywhere else TAB lists the possible
   completions of a device/filename.]
grub> quit
quit
[root@localhost liveuser]#

I came across a bug report which seems to address the GRUB shell scrolling: https://bugzilla.redhat.com/show_bug.cgi?id=134442

Therefore I did this:

Code:

[root@localhost liveuser]# echo $TERM
xterm
[root@localhost liveuser]# export TERM=gnome
[root@localhost liveuser]# echo $TERM
gnome
[root@localhost liveuser]# grub

With no change in the behavior of the GRUB shell whatsoever.

maxkukartsev · 07-23-2009, 09:20 PM

So for everyone else who installed x86 Fedora 11 (GNOME version), the GRUB shell works like it should? It interprets the TAB character correctly?

maxkukartsev · 07-24-2009, 05:57 PM

The problem was apparently lack of the NCurses library.

I decided to rebuild GRUB-0.97, so I downloaded grub-0.97.tar.gz from ftp://alpha.gnu.org/gnu/grub/, and while executing the ./configure script I had the messages:

Code:

checking for wgetch in -lncurses... no
checking ncurses/curses.h usability... no
checking ncurses/curses.h presence... no
checking for ncurses/curses.h... no
checking ncurses.h usability... no
checking ncurses.h presence... no
checking for ncurses.h... no
checking curses.h usability... no
checking curses.h presence... no
checking for curses.h... no

But this did not give me errors. The ./configure script must've left the ncurses library out of the build process. When compiled I launched GRUB, I experienced the same broken shell behavior.

I installed package ncurses-devel and ran ./configure again, and it found the ncurses header files. After compiling and running GRUB, it worked like it is supposed to!

So, I think that on Fedora 11 32-bit, the installed GRUB-0.97 was compiled without ncurses

Escher · 07-26-2009, 05:55 AM

thanks maxkukartsev, that enables tab completion in a grub shell for me too, I wonder why they disable it in the default build?

Strangely, it works fine if you run a grub command prompt at boot time.

Otherwise I would have suggested that they needed to reduce the size of the grub binary due to the static linking requirement (grub must be linked against glibc-static since no dynamic libs are available at boot time)

Perhaps there should be a separate grub-shell command, which is dynamically linked against all the libs.

maxkukartsev · 07-27-2009, 12:39 AM

Hi Escher,

Glad to hear this helped you out.

Quote:

Originally Posted by Escher

Strangely, it works fine if you run a grub command prompt at boot time.

Yeah, so basically this means that native GRUB and Linux GRUB are independent from each other. I think that because the native GRUB doesn't have the benefits of Linux' shell framework, it implements I/O a little differently, and may be the cause of the different behaviors.

Quote:

Originally Posted by Escher

Perhaps there should be a separate grub-shell command, which is dynamically linked against all the libs.

Maybe the developers chose to have only a static Linux GRUB program because they wanted to keep it similar to the native GRUB program?

Quote:

Originally Posted by Escher

I wonder why they disable it in the default build?

Yeah, I'm dumbfounded at why NCurses was not statically linked into Fedora 11/10 from the start, as it is on other distributions such as Ubuntu.

Best regards,
Max Kukartsev