Re: Locating a configuration file (*.cfg)

[Andrei Borzenkov]

30.10.2015 15:37, Arbiel (gmx) пишет:
> > > 2) Having located the configuration file to branch to, configfile allows
> > > for the branching of grub to that file. How does configfile handle the
> > > ${config_directory} variable ? If this variable is not set to this "new"
> > > grub directory, how is it possible to deduce the name of this directory
> > > from the fully qualified name of the "new" configuration file ?
> > config_directory and config_file should be set to the correct value
> > when entering new configuration file. If not, please report together
> > with instructions how to reproduce.
> a) I never saw any reference to config_file, neither in the
> documentation, nor my configuration files. What value is it supposed to
> hold ?

The name of configuration file that is being processed using 
"configfile" command. I actually was sure I documented them but 
apparently patch stuck. I need to do it.

> b) are those two variables to be exported ?
> >

GRUB does it.

> > > 3) To complement this grub script, I want to write a bash script to set
> > > a environment variable which the grub script has to reset. grub seems to
> > > not support save_env to a grubenv file located on a logical volume. Is
> > > it possible to replace the load_env and a save_env commands by
> > > identically named functions which would use these 2 commands with the -f
> > > parameter (and doing so, would allow for the correct operation of
> > > recordfail) ?
> > There is no support for writing on top of diskfilter devices - LVM,
> > Linux MD etc. It may be possible to implement limited support for
> > linear and RAID0 type of storage. Anything else is too complicated to
> > warrant doing it. I would be happy if someone could suggest
> > implementation that allowed environment block to be located anywhere,
> > not only as file on a filesystem. openSUSE does something similar for
> > btrfs as special case.
> My question was maybe not clear enough. I meant in "to replace load_env …"
> writing in my script sort of an alias to overwrite the commands.

Can you "replace write system call" to write to a file system that is 
mounted read-only?

> On another hand, wouldn't it be possible to add a parameter to
> grub-mkconfig to define a write-eligible environment block and reference
> it in the various "load_env" et "save_env" used by grub.cfg ?
> >

How are you going to identify device where this block is located?