Re: [PATCH 1/3] Add an exception handle check function

[Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 12/21/2012 04:55 PM, Baoquan He wrote:
> In some cases, exception happened, default handling is called. However,
> user may not like the handling, want to specify a handler for these
> exceptions.
> 
> Add an exception handle check function. Call it where exceptions happened,
> and specify a extra special handler. If user want the special handler handles
> this exception, related cmdline is added.
> 
> Then Dracut will check the cmdline, if related cmdline exists, call the
> specified handler; if not, call the default handler.
> 
> The function can be called like below:
> exception_handle_check -h continue_on_fail

I think exception_handle is not a good name, how about use "failaction"
instead?

And maybe use below action names:
failaction=continue/shell

IMHO, reboot is not useful for usual initrd. For kdump add a "continue"
is enough because kdump module will handle failure of itself as long as
dracut ignore previous failures.

These 3 patches should better to be one patch. Or split them to 2
patches as below
1/2: make emergency_shell as a fail action
2/2: add a new fail action of "continue"

> 
> Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  modules.d/99base/dracut-lib.sh |   40 ++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 40 insertions(+), 0 deletions(-)
> 
> diff --git a/modules.d/99base/dracut-lib.sh b/modules.d/99base/dracut-lib.sh
> index cc6c7e8..35ed3a3 100755
> --- a/modules.d/99base/dracut-lib.sh
> +++ b/modules.d/99base/dracut-lib.sh
> @@ -938,6 +938,46 @@ emergency_shell()
>      [ -e /run/initramfs/.die ] && exit 1
>  }
>  
> +exception_handle_check()
> +{
> +    local action_wanted
> +    if [ "$1" = "-h" ]; then
> +        [ $# -le 1 ] && echo "No exception handler specified" && emergency_shell

Not necessary use "-h", just make shell as the default action.

Add a functions like get_fail_action(), and do_fail_action(), call them
at different points.

> +        action_wanted=$2; 
> +        case "$action_wanted" in
> +        continue_on_fail)
> +            ;;
> +        reboot)
> +            ;;
> +        emergency_shell)
> +            ;;
> +        *)
> +            echo "Wrong exception handler input: $action_wanted"
> +            action_wanted=emergency_shell
> +        esac
> +    else
> +        action_wanted=emergency_shell
> +    fi
> +
> +    case "$action_wanted" in
> +    continue_on_fail)
> +        action=$(getarg rd.exceptionhandler=)
> +        [ -z "$action" -o  "$action" != "continue_on_fail" ]  && emergency_shell
> +        ;;
> +    emergency_shell)
> +        emergency_shell
> +        ;;
> +    reboot)
> +        reboot -f
> +        ;;
> +    *) #default
> +        ##impossible come here
> +        ;;
> +    esac
> +
> +    return 0
> +}
> +
>  # Retain the values of these variables but ensure that they are unexported
>  # This is a POSIX-compliant equivalent of bash's "export -n"
>  export_n()
> 


-- 
Thanks
Dave