Re: Using grub, is it possible to use "if, while" during booting (before loading normal.mod)?

[Andrey Borzenkov]

В Tue, 13 Aug 2013 07:33:28 -0700
Binh Minh <address@hidden> пишет:

> It is a security feature requires my implementation to ask for the user's
> input and compare the input before we process information in grub.cfg.  It
> is proprietary so I can't discuss more than that.  If I include modules
> echo, sleep, read during grub-mkimage, I was able to have those commands in
> myconfig.cfg, and this works before normal.mod is loaded.  But how come
> "if" statement is unknown?  The grub documentation on this web site
> http://www.gnu.org/software/grub/manual/html_node/Embedded-configuration.htmlhas
> an example showing using "if" statement is possible.  What kind of
> built-in script parser is used when processing the "config file" that was
> linked into core.img?
> 

normal.mod. Quoting documentation:

To do this, include the `configfile' and `normal' modules in the core
image,

> 
> On Tue, Aug 13, 2013 at 2:39 AM, Andrey Borzenkov <address@hidden>wrote:
> 
> > On Tue, Aug 13, 2013 at 9:10 AM, Binh Minh <address@hidden>
> > wrote:
> > > I am trying to read in a user's input, compare the user's input to X.  If
> > > the user's input matches X, proceed to load normal.mod; otherwise loop
> > back
> > > to get user's input.
> > >
> > >
> >
> > And why you cannot do it after normal.mod is loaded?
> >
> > > On Mon, Aug 12, 2013 at 7:39 PM, Andrey Borzenkov <address@hidden>
> > > wrote:
> > >>
> > >> В Mon, 12 Aug 2013 13:39:24 -0700
> > >> Binh Minh <address@hidden> пишет:
> > >>
> > >> > My computer has grub installed. During booting before normal.mod is
> > >> > loaded,
> > >> > I need to be able to run if and while commands in my config file which
> > >> > has
> > >> > been linked into core.img (using grub-mkimage -c myconfig.confg). In
> > >> > myconfig.config, I have an if statement and I kept getting "unknown
> > >> > command
> > >> > if" during booting.  I saw an example in
> > >> >
> > >> >
> > http://www.gnu.org/software/grub/manual/html_node/Embedded-configuration.htmland
> > >> > looks like I just need to include search, test, and normal modules.
> > >> > Am
> > >> > I missing something?  Thanks
> > >>
> > >> It is not possible. Those commands are provide by normal.mod. The only
> > >> purpose of core.img is normally to load normal.mod.
> > >>
> > >> What are you trying to do?
> > >
> > >
> >