Re: [PATCH] Add fwconfig command

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Jan 23, 2017 at 03:43:32PM -0800, Matthew Garrett wrote:
> Add a command to read values from the qemu fwcfg store. This allows data
> to be passed from the qemu command line to grub.
> 
> Example use:
> 
> echo '(hd0,1)' >rootdev
> qemu -fw_cfg opt/rootdev,file=rootdev
> 
> fwconfig opt/rootdev root
> ---
>  docs/grub.texi                |   6 +++
>  grub-core/Makefile.core.def   |   6 +++
>  grub-core/commands/fwconfig.c | 121 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 133 insertions(+)
>  create mode 100644 grub-core/commands/fwconfig.c
> 
> diff --git a/docs/grub.texi b/docs/grub.texi
> index 4469638..4f8a378 100644
> --- a/docs/grub.texi
> +++ b/docs/grub.texi
> @@ -3818,6 +3818,7 @@ you forget a command, you can run the command @command{help}
>  * eval::                        Evaluate agruments as GRUB commands
>  * export::                      Export an environment variable
>  * false::                       Do nothing, unsuccessfully
> +* fwconfig::                    Retrieves a value from the qemu fwcfg store
>  * getenv::                      Retrieve an EFI firmware variable
>  * gettext::                     Translate a string
>  * gptsync::                     Fill an MBR based on GPT entries
> @@ -4259,6 +4260,11 @@ Do nothing, unsuccessfully.  This is mainly useful in control constructs
>  such as @code{if} and @code{while} (@pxref{Shell-like scripting}).
>  @end deffn
>  
> +@node fwconfig
> +@subsection fwconig
> +@deffn Command fwconfig fwpath envvar
> +Retrieves @var{fwpath} from the qemu fwcfg store and stores it in @var{envvar}
> +
>  @node getenv
>  @subsection getenv
>  
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index db77a7f..f6b6f38 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -2362,3 +2362,9 @@ module = {
>    common = loader/i386/xen_file64.c;
>    extra_dist = loader/i386/xen_fileXX.c;
>  };
> +
> +module = {
> +  name = fwconfig;
> +  common = commands/fwconfig.c;
> +  enable = x86;
> +};
> diff --git a/grub-core/commands/fwconfig.c b/grub-core/commands/fwconfig.c
> new file mode 100644
> index 0000000..289d167
> --- /dev/null
> +++ b/grub-core/commands/fwconfig.c
> @@ -0,0 +1,121 @@
> +/* fwconfig.c - command to read config from qemu fwconfig  */
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2015  CoreOS, Inc.


Hmm, 

See https://www.gnu.org/licenses/why-assign.html


> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.

So what is your option here (see the 'at your option'). 

> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */