Re: [make-initrd] [PATCH v6 10/22] bootchain-core: expanded addressing capabilities

[Alexey Gladkov <gladkov.alexey@gmail.com>]

On Sun, Oct 24, 2021 at 08:21:28PM +0300, Leonid Krivoshein wrote:
> Adds support for reverse addressing relative to the current step,
> as well as calculating the path to the special device node obtained
> in the previous step.
> 
> Signed-off-by: Leonid Krivoshein <klark.devel@gmail.com>
> ---
>  features/bootchain-core/README.md             |  6 +++
>  .../data/bin/bootchain-sh-functions           | 37 ++++++++++++++++---
>  2 files changed, 38 insertions(+), 5 deletions(-)
> 
> diff --git a/features/bootchain-core/README.md b/features/bootchain-core/README.md
> index 8d341e0..ba66259 100644
> --- a/features/bootchain-core/README.md
> +++ b/features/bootchain-core/README.md
> @@ -49,6 +49,12 @@ us to optimize fill in `initramfs` only which we are need.
>  
>  - Modularity: loading methods are initially separated from the common
>    code and daemon.
> +- Via resolve_target() supports not only forward, but also reverse addressing,
> +  relative to the current step. For example, a record like `step-3/dir1/dev`
> +  will process the result of `dir1/dev`, made in the third step from the current
> +  one. Together with the overload of the chain of steps, direct addressing is safe
> +  only when storing the numbers of the completed steps in files, whereas reverse
> +  relative addressing it is safe in any case and can often be more convenient.

На мой взгляд очень непонятный синтаксис. step1 и step-1 кажется
одинаковым. Хотя бы current-1

>  - Allows you to work with shorter and more familiar paths to special files
>    devices thanks to the use of `DEVNAME` along with `dev`.
>  
> diff --git a/features/bootchain-core/data/bin/bootchain-sh-functions b/features/bootchain-core/data/bin/bootchain-sh-functions
> index e73fd35..0eebbaf 100644
> --- a/features/bootchain-core/data/bin/bootchain-sh-functions
> +++ b/features/bootchain-core/data/bin/bootchain-sh-functions
> @@ -27,19 +27,46 @@ get_parameter()
>  resolve_target()
>  {
>  	local target="$1"
> +	local where="${target%%/*}"
> +	local n="${#where}"
>  
> -	case "${target%%/*}" in
> +	target="${target:$n}"
> +
> +	case "$where" in
>  	'')
>  		;;
>  	pipe[0-9]|pipe[0-9][0-9]|pipe[0-9][0-9][0-9])
> -		target="$mntdir/dst/step${target:4}"
> +		[ -d "$mntdir/dst/step${where:4}" ] ||
> +			return 0
> +		target="$(readlink-e "$mntdir/dst/step${where:4}")${target}"
> +		;;
> +	step-[1-9]|step-[1-9][0-9]|step-[1-9][0-9][0-9])
> +		case "$destdir" in
> +		"$mntdir"/dst/step[0-9]*)
> +			n="${destdir##*/}"
> +			n="$(( ${n:4} - ${where:5} ))"
> +			;;
> +		*)
> +			return 0
> +			;;
> +		esac
> +		[ "$n" -ge 0 ] && [ -d "$mntdir/dst/step$n" ] ||
> +			return 0
> +		target="$(readlink-e "$mntdir/dst/step$n")${target}"
>  		;;
>  	*)
>  		if [ -z "${prevdir-}" ]; then
> -			message "no previous stop to use"
> -			return
> +			message "no previous step results to use with $name"
> +			return 0
> +		fi
> +		if [ -z "$target" ] &&
> +		   [ "$where" = DEVNAME ] &&
> +		   [ -s "$prevdir"/DEVNAME ]
> +		then
> +			read -r target <"$prevdir"/DEVNAME ||:
> +		else
> +			target="$prevdir/${where#/}${target}"
>  		fi
> -		target="$prevdir/${target#/}"
>  		;;
>  	esac
>  
> -- 
> 2.24.1
> 
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-- 
Rgrds, legion