whereis grub shell ?

whereis grub shell ?

[yoram bar haim]

Hello all
I am new to this list so I first would like to thank all the people doing good 
work here.
and after that, I complied grub 1.96, and could not find anything look like a 
grub shell that can be run from user-space. am i missing something here ? 
where is it ?
-- 
This message was sent from Debian GNU/Linux lenny/sid

Re: whereis grub shell ?

[Pavel Roskin]

On Sun, 2008-03-16 at 22:41 +0200, yoram bar haim wrote:
> Hello all
> I am new to this list so I first would like to thank all the people doing good 
> work here.
> and after that, I complied grub 1.96, and could not find anything look like a 
> grub shell that can be run from user-space. am i missing something here ? 
> where is it ?

It's optional.  Please give "--enable-grub-emu" to configure.  The name
of the executable is "grub-emu".

-- 
Regards,
Pavel Roskin

Re: whereis grub shell ?

[yoram bar haim]

On Sunday 16 March 2008 22:49:12 Pavel Roskin wrote:
> On Sun, 2008-03-16 at 22:41 +0200, yoram bar haim wrote:
> > Hello all
> > I am new to this list so I first would like to thank all the people doing
> > good work here.
> > and after that, I complied grub 1.96, and could not find anything look
> > like a grub shell that can be run from user-space. am i missing something
> > here ? where is it ?
>
> It's optional.  Please give "--enable-grub-emu" to configure.  The name
> of the executable is "grub-emu".

Thanks
I suspected that, but grub-emu just make my terminal show nothing, so I can't 
even tell if it works or not, the only thing I can see is the "verbose" info 
messages.
Well, i guess I will have to start working on this... :)

-- 
This message was sent from Debian GNU/Linux lenny/sid

Re: whereis grub shell ?

[yoram bar haim]

On Sunday 16 March 2008 22:49:12 Pavel Roskin wrote:
> On Sun, 2008-03-16 at 22:41 +0200, yoram bar haim wrote:
> > Hello all
> > I am new to this list so I first would like to thank all the people doing
> > good work here.
> > and after that, I complied grub 1.96, and could not find anything look
> > like a grub shell that can be run from user-space. am i missing something
> > here ? where is it ?
>
> It's optional.  Please give "--enable-grub-emu" to configure.  The name
> of the executable is "grub-emu".

I found out how to make it work for me, thanks, it seems to hold when I start 
it without --root-dir

-- 
This message was sent from Debian GNU/Linux lenny/sid

Re: whereis grub shell ?

[Robert Millan]

On Sun, Mar 16, 2008 at 04:49:12PM -0400, Pavel Roskin wrote:
> On Sun, 2008-03-16 at 22:41 +0200, yoram bar haim wrote:
> > Hello all
> > I am new to this list so I first would like to thank all the people doing good 
> > work here.
> > and after that, I complied grub 1.96, and could not find anything look like a 
> > grub shell that can be run from user-space. am i missing something here ? 
> > where is it ?
> 
> It's optional.  Please give "--enable-grub-emu" to configure.  The name
> of the executable is "grub-emu".

But it isn't the "grub shell" anymore.  We call it grub-emu because it's simply
meant to emulate grub, and is only useful for debugging (unlike the grub shell).

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)

Re: whereis grub shell ?

[yoram bar haim]

On Tuesday 18 March 2008 14:02:13 Robert Millan wrote:
> But it isn't the "grub shell" any

So a real grub-hsell functionality does not exist anymore ?
I work on grub2 support in the restart menu of kde4 everything (parsing 
grub.cfg and letting the user choose boot option) works except of really 
settings the defualt option for next boot... I can modify grub.cfg but is 
ugly. is there a good way to do this ?

on leggacy grub it is done simply by running "grub --batch" with pipe and 
writing "savedefault --defualt=n" to the pipe, what can be done in grub2 ?
-- 
This message was sent from Debian GNU/Linux lenny/sid

Re: whereis grub shell ?

[Robert Millan]

On Tue, Mar 18, 2008 at 09:31:28PM +0200, yoram bar haim wrote:
> On Tuesday 18 March 2008 14:02:13 Robert Millan wrote:
> > But it isn't the "grub shell" any
> 
> So a real grub-hsell functionality does not exist anymore ?
> I work on grub2 support in the restart menu of kde4 everything (parsing 
> grub.cfg and letting the user choose boot option) works except of really 
> settings the defualt option for next boot... I can modify grub.cfg but is 
> ugly. is there a good way to do this ?

I don't understand what you want to do.  But the usual way to generate
grub.cfg is with update-grub.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)

Re: whereis grub shell ?

[Pavel Roskin]

On Tue, 2008-03-18 at 21:31 +0200, yoram bar haim wrote:
> On Tuesday 18 March 2008 14:02:13 Robert Millan wrote:
> > But it isn't the "grub shell" any
> 
> So a real grub-hsell functionality does not exist anymore ?

It depends on what you mean.

> I work on grub2 support in the restart menu of kde4 everything (parsing 
> grub.cfg and letting the user choose boot option) works except of really 
> settings the defualt option for next boot... I can modify grub.cfg but is 
> ugly. is there a good way to do this ?

In my opinion, modifying anything by directly accessing the filesystem
on a running OS is much, much uglier.

> on leggacy grub it is done simply by running "grub --batch" with pipe and 
> writing "savedefault --defualt=n" to the pipe, what can be done in grub2 ?

There is no "savedefault".  It hasn't been implemented yet.  And if it's
implemented, I would actually prefer that grub-emu is only allowed to do
it by the means of hostfs, not directly.

-- 
Regards,
Pavel Roskin

Re: whereis grub shell ?

[yoram bar haim]

On Tuesday 18 March 2008 22:37:13 Pavel Roskin wrote:
> On Tue, 2008-03-18 at 21:31 +0200, yoram bar haim wrote:
> > On Tuesday 18 March 2008 14:02:13 Robert Millan wrote:
> > > But it isn't the "grub shell" any
> >
> > So a real grub-hsell functionality does not exist anymore ?
>
> It depends on what you mean.
>
> > I work on grub2 support in the restart menu of kde4 everything (parsing
> > grub.cfg and letting the user choose boot option) works except of really
> > settings the defualt option for next boot... I can modify grub.cfg but is
> > ugly. is there a good way to do this ?
>
> In my opinion, modifying anything by directly accessing the filesystem
> on a running OS is much, much uglier.
>
> > on leggacy grub it is done simply by running "grub --batch" with pipe and
> > writing "savedefault --defualt=n" to the pipe, what can be done in grub2
> > ?
>
> There is no "savedefault".  It hasn't been implemented yet.  And if it's
> implemented, I would actually prefer that grub-emu is only allowed to do
> it by the means of hostfs, not directly.

I respcetfully disagree. I think that if possible, host filesystems should 
only be accessed as "readonly" by a bootloader. that also saves the efforts 
of implementing safe writing capabilities to all filesystems that grub can 
possibly read configuration from.
I understand that any alternative (probably exploiting reserved byte at the 
MBR or bootsector) is durty hack, so if there is an agreed way to 
implement "savedefault" but no time to do that, I will be happy to help by 
implementing it in any way that is agreed by the good people here.

again, respectfully.

-- 
This message was sent from Debian GNU/Linux lenny/sid

Re: whereis grub shell ?

[Pavel Roskin]

On Wed, 2008-03-19 at 23:58 +0200, yoram bar haim wrote:
> On Tuesday 18 March 2008 22:37:13 Pavel Roskin wrote:
> > There is no "savedefault".  It hasn't been implemented yet.  And if it's
> > implemented, I would actually prefer that grub-emu is only allowed to do
> > it by the means of hostfs, not directly.
> 
> I respcetfully disagree. I think that if possible, host filesystems should 
> only be accessed as "readonly" by a bootloader.

We are talking about different things.  grub-emu is not a bootloader,
it's a userspace program.

Anyway, the functionality for writing to files from the bootloader was
present in GRUB 1, and I think it can be ported to GRUB 2.  Perhaps it
would be nice to have extra sanity checks for the filesystems that
checksum, compress or mirror the data.

But generally, it's a widely used feature, and I'm not aware of many
users having their filesystems trashed by GRUB 1.

>  that also saves the efforts 
> of implementing safe writing capabilities to all filesystems that grub can 
> possibly read configuration from.

Please note that it's not a general writing capability.  It's a
capability of writing to a certain short file without changing its
length or any metadata (timestamps etc).  If necessary, the file can be
created by a userspace utility that would try to ensure that the file is
contiguous and uncompressed.  The file could also include its sector
number at the time of creation, so that the bootloader would not write
to the file if it was relocated.

> I understand that any alternative (probably exploiting reserved byte at the 
> MBR or bootsector) is durty hack, so if there is an agreed way to 
> implement "savedefault" but no time to do that, I will be happy to help by 
> implementing it in any way that is agreed by the good people here.

It should be possible to write to the GRUB bootloader in the MBR or in
the reserved part of the filesystem, but it's actually less portable.
The low-level details of GRUB installation may be different on different
systems.  Besides, there is less space there.  It would be nice to have
a whole sector (512 bytes) available.

I think nobody would object that we need savedefault functionality that
is safe and reasonably portable.  As for the details, perhaps whoever
supplies the patch should have a choice.

I don't think anyone expects savedefault to work under any conditions,
such as RAID, LVM and particularly nasty filesystems.  But ext2 and fat
should work.

-- 
Regards,
Pavel Roskin

Re: whereis grub shell ?

[Robert Millan]

On Wed, Mar 19, 2008 at 07:04:55PM -0400, Pavel Roskin wrote:
> 
> But generally, it's a widely used feature, and I'm not aware of many
> users having their filesystems trashed by GRUB 1.

For the record, this has happened.  See for example:

  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=462701

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)