shell-cmdline

#!/bin/sh -efu
### This file is covered by the GNU General Public License,
### which should be included with libshell as the file LICENSE.
### All copyright information are listed in the COPYING.

if [ -z "${__included_shell_cmdline-}" ]; then
__included_shell_cmdline=1

. shell-string

### Run handler for each variable in /proc/cmdline.
cmdline_foreach()
{
	local l h c='' m=''

	l="$1"; shift
	h="$1"; shift

	__is_set() {
		[ $(( $1 & $2 )) -eq $2 ]
	}

	fill_mask m "$l"

	local state=$((0))
	local VALUE=$((2))
	local EQUAL=$((4))
	local QUOTE=$((16))

	local n='' v='' f=1

	while [ -n "$l" ]; do
		c="${l%$m}"

		case "$c" in
			'"')
				__is_set $state $QUOTE &&
					state=$(($state ^ $QUOTE)) ||
					state=$(($state | $QUOTE))
				;;
			' ')
				if __is_set $state $QUOTE; then
					v="$v$c"
				else
					f=
					__is_set $state $EQUAL ||
						{ v=1; f=1; }
					$h "$n" "$v" "$f" ||
						break
					n='' v='' f=''
					state=$((0))
				fi
				;;
			'=')
				! __is_set $state $VALUE ||
					v="$v$c"
				state=$(($state | $VALUE | $EQUAL))
				;;
			*)
				if ! __is_set $state $VALUE; then
					[ "$c" != '-' ] || c='_'
					n="$n$c"
				else
					v="$v$c"
				fi
				;;
		esac

		l="${l#?}"
		m="${m#?}"
	done

	if [ -n "$n" ]; then
		f=
		__is_set $state $EQUAL ||
			{ v=1; f=1; }
		$h "$n" "$v" "$f" ||:
	fi

	unset -f __is_set
}

### Find spicified variable in /proc/cmdline and store result into variable.
### Usage example:
###   read cmdline < /proc/cmdline
###   cmdline_get 'initrd_value' 'initrd' "$cmdline"
###   echo "$initrd_value"
### or:
###   cmdline_get 'initrd_value' 'initrd'
###   echo "$initrd_value"
###
cmdline_get()
{
	local __cmdline __retv __getn

	__retv="$1"; shift
	__getn="$1"; shift
	if [ "$#" -eq 0 ]; then
		read -r __cmdline < /proc/cmdline
	else
		__cmdline="$1"
	fi

	local c m l="$__getn"
	__getn=

	fill_mask m "$l"
	while [ -n "$l" ]; do
		c="${l%$m}"
		[ "$c" != '-' ] || c='_'
		__getn="$__getn$c"
		l="${l#?}"
		m="${m#?}"
	done
	unset c m l

	__getval()
	{
		[ "$1" != "$__getn" ] || eval "$__retv=\"\$2\""
	}
	cmdline_foreach "$__cmdline" __getval
	unset -f __getval
}

fi #__included_shell_cmdline