Re: [PATCH 1/2] common/rc: add _require_kernel_config and _has_kernel_config

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Nov 08, 2021 at 04:19:15PM +0100, Lukas Czerner wrote:
> Add _require_kernel_config() and _has_kernel_config() helpers to check
> whether a specific kernel configuration is enabled on the kernel.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
>  common/config |  1 +
>  common/rc     | 29 +++++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/common/config b/common/config
> index 164381b7..e0a5c5df 100644
> --- a/common/config
> +++ b/common/config
> @@ -226,6 +226,7 @@ export OPENSSL_PROG="$(type -P openssl)"
>  export ACCTON_PROG="$(type -P accton)"
>  export E2IMAGE_PROG="$(type -P e2image)"
>  export BLKZONE_PROG="$(type -P blkzone)"
> +export GZIP_PROG="$(type -P gzip)"
>  
>  # use 'udevadm settle' or 'udevsettle' to wait for lv to be settled.
>  # newer systems have udevadm command but older systems like RHEL5 don't.
> diff --git a/common/rc b/common/rc
> index 0d261184..84154868 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -4703,6 +4703,35 @@ _require_names_are_bytes() {
>          esac
>  }
>  
> +_has_kernel_config()
> +{
> +	option=$1
> +	uname=$(uname -r)
> +	config_list="$KCONFIG_PATH

This new KCONFIG_PATH variable should be documented in the README.

Otherwise, the logic looks solid.

--D

> +		     /proc/config.gz
> +		     /lib/modules/$uname/build/.config
> +		     /boot/config-$uname
> +		     /lib/kernel/config-$uname"
> +
> +	for config in $config_list; do
> +		[ ! -f $config ] && continue
> +		[ $config = "/proc/config.gz" ] && break
> +		grep -qE "^${option}=[my]" $config
> +		return
> +	done
> +
> +	[ ! -f $config ] && _notrun "Could not locate kernel config file"
> +
> +	# We can only get here with /proc/config.gz
> +	_require_command "$GZIP_PROG" gzip
> +	$GZIP_PROG -cd $config | grep -qE "^${option}=[my]"
> +}
> +
> +_require_kernel_config()
> +{
> +	_has_kernel_config $1 || _notrun "Installed kernel not built with $1"
> +}
> +
>  init_rc
>  
>  ################################################################################
> -- 
> 2.31.1
>