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

[Binh Minh]

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.html has 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?

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?
>
>