Re: [PATCH 4/6] rootfs-block: Support lilo style device numbers.

[Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

Am 23.01.2013 21:15, schrieb Colin Guthrie:
> Lilo supplies root=900 rather than root=/dev/md0. Similarly it would say root=801 rather
> than root=/dev/sda1.
> 
> This patch simply interprets that number and creates appropriate udev rules
> to create the /dev/root symlink as needed.
> ---
>  modules.d/95rootfs-block/block-genrules.sh | 11 ++++++++++-
>  modules.d/95rootfs-block/parse-block.sh    |  4 ++++
>  2 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/modules.d/95rootfs-block/block-genrules.sh b/modules.d/95rootfs-block/block-genrules.sh
> index 7f894ee..161183e 100755
> --- a/modules.d/95rootfs-block/block-genrules.sh
> +++ b/modules.d/95rootfs-block/block-genrules.sh
> @@ -2,7 +2,16 @@
>  # -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
>  # ex: ts=8 sw=4 sts=4 et filetype=sh
>  
> -if [ "${root%%:*}" = "block" ]; then
> +if [ -n "$rootdevnum" ]; then
> +    major=$(( 0x$rootdevnum / 256 ))
> +    minor=$(( 0x$rootdevnum - ( $major * 256 ) ))
> +    {
> +        printf 'ACTION=="add|change", ENV{MAJOR}=="%d", ENV{MINOR}=="%d", SYMLINK+="root"\n' \
> +            $major $minor
> +    } >> /etc/udev/rules.d/99-root.rules
> +
> +    wait_for_dev /dev/root
> +elif [ "${root%%:*}" = "block" ]; then
>      {
>          printf 'KERNEL=="%s", SYMLINK+="root"\n' \
>              ${root#block:/dev/}
> diff --git a/modules.d/95rootfs-block/parse-block.sh b/modules.d/95rootfs-block/parse-block.sh
> index 3745352..9efc51f 100755
> --- a/modules.d/95rootfs-block/parse-block.sh
> +++ b/modules.d/95rootfs-block/parse-block.sh
> @@ -19,4 +19,8 @@ case "$root" in
>      /dev/*)
>          root="block:${root}"
>          rootok=1 ;;
> +    [1-9][0-9][0-9])
> +        rootdevnum=$root
> +        root=block:/dev/root

I would do just:

major=$(( 0x$root / 256 ))
minor=$(( 0x$root - ( $major * 256 ) ))
root=/dev/block/$major:$minor


> +        rootok=1 ;;
>  esac
>