Re: [RFC] 90crypt: key on rem. device enhancements

[Karel Zak <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Fri, Sep 24, 2010 at 11:18:07PM +0200, Amadeusz Żołnowski wrote:
> +# Evaluate command for every given device.  Every single device must be
> +# specified either by path, by label prefixed with 'LABEL=' or UUID prefixed
> +# with 'UUID='.  UUIDs are processed by 'foreach_uuid_until'.  List elements'
> +# order is preserved.
> +#
> +# foreach_dev_until command devices
> +#
> +# command - command to be evaluated
> +# devices - list of devices separated by space
> +#
> +# The function returns after *first successful evaluation* of the given command
> +# with status 0.  If evaluation fails for every device, function returns with
> +# status 1.
> +#
> +# Example:
> +# foreach_dev_until "echo \$___; false" "/dev/sda1 LABEL=boot UUID=123a"
> +foreach_dev_until() {
> +    local cmd="$1"; shift; local devs_list="$*"
> +    local dev; local ___
> +
> +    [ -n "${cmd}" ] || return 1
> +
> +    if [ -n "${devs_list}" ]; then
> +        for dev in ${devs_list}; do
> +            if strstarts "${dev}" 'UUID='; then
> +                foreach_uuid_until -p 'UUID=' "${cmd}" "${dev#UUID=*}" && \
> +                        return 0
> +            else
> +                [ -e "${dev}" ] || [ -e "/dev/disk/by-label/${dev#LABEL=}" ] \

 hmm.. how does it work with blank or non-ascii chars in LABELs?

 ...

> +# It's a wrapper around 'mount' command.  In addition to 'mount' you can specify
> +# device name like "UUID=01234567-89ab-cdef-0123-4567890abcde" and
> +# "LABEL=fun_label".  'do_mount' mounts device as read-only for default.  To
> +# mount as writable pass '-w' option.  'mount_point' argument is required.
> +#
> +# do_mount [options] dev mount_point
> +#
> +# Extra options:
> +#   -q    Suppress any output.
> +#
> +# Example:
> +# do_mount -q -w LABEL=blah /mnt/disk
> +do_mount() {
> +    local args; local quiet
> +
> +    while [ $# -gt 2 ]; do
> +        case $1 in
> +            -q) quiet='2>/dev/null >/dev/null' ;;
> +            -v) quiet=''; args="${args} $1" ;;
> +            *) args="${args} $1" ;;
> +        esac
> +        shift
> +    done
> +
> +    local dev_name="$1"; local dev="${dev_name#*=}"; local mount_point="$2"
> +
> +    case ${dev_name} in
> +        -*) die 'do_mount - wrong usage!' ;;
> +        UUID=*) args="${args} -U" ;;
> +        LABEL=*) args="${args} -L" ;;

 mount(8) supports LABEL= and UUID= tags, for example
 
    mount LABEL=boot /mnt/test
 
 so, you does not need to convert these tags to -L or -U options.

    Karel

-- 
 Karel Zak  <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
 http://karelzak.blogspot.com