openwrt-xburst/package/base-files/files/lib/functions/boot.sh

#!/bin/sh
# Copyright (C) 2006-2010 OpenWrt.org
# Copyright (C) 2010 Vertical Communications

mount() {
	/bin/busybox mount -o noatime "$@"
}

boot_hook_splice_start() {
	export -n PI_HOOK_SPLICE=1
}

boot_hook_splice_finish() {
	local hook
	for hook in $PI_STACK_LIST; do
		local v; eval "v=\${${hook}_splice:+\$${hook}_splice }$hook"
		export -n "${hook}=${v% }"
		export -n "${hook}_splice="
	done
	export -n PI_HOOK_SPLICE=
}

boot_hook_init() {
	local hook="${1}_hook"
	export -n "PI_STACK_LIST=${PI_STACK_LIST:+$PI_STACK_LIST }$hook"
	export -n "$hook="
}

boot_hook_add() {
	local hook="${1}_hook${PI_HOOK_SPLICE:+_splice}"
	local func="${2}"

	[ -n "$func" ] && {
		local v; eval "v=\$$hook"
		export -n "$hook=${v:+$v }$func"
	}
}

boot_hook_shift() {
	local hook="${1}_hook"
	local rvar="${2}"

	local v; eval "v=\$$hook"
	[ -n "$v" ] && {
		local first="${v%% *}"

		[ "$v" != "${v#* }" ] && \
			export -n "$hook=${v#* }" || \
			export -n "$hook="

		export -n "$rvar=$first"
		return 0
	}

	return 1
}

boot_run_hook() {
	local hook="$1"
	local func

	while boot_hook_shift "$hook" func; do
		local ran; eval "ran=\$PI_RAN_$func"
		[ -n "$ran" ] || {
			export -n "PI_RAN_$func=1"
			$func "$1" "$2"
		}
	done
}

find_mtd_part() {
	local PART="$(grep "\"$1\"" /proc/mtd | awk -F: '{print $1}')"
	local PREFIX=/dev/mtdblock
	
	PART="${PART##mtd}"
	[ -d /dev/mtdblock ] && PREFIX=/dev/mtdblock/
	echo "${PART:+$PREFIX$PART}"
}

jffs2_ready () {
	mtdpart="$(find_mtd_part rootfs_data)"
	[ -z "$mtdpart" ] && return 1
	magic=$(hexdump $mtdpart -n 4 -e '4/1 "%02x"')
	[ "$magic" != "deadc0de" ]
}

dupe() { # <new_root> <old_root>
	cd $1
	echo -n "creating directories... "
	{
		cd $2 
		find . -xdev -type d
		echo "./dev ./overlay ./mnt ./proc ./tmp"
		# xdev skips mounted directories
		cd $1 
	} | xargs mkdir -p
	echo "done"

	echo -n "setting up symlinks... "
	for file in $(cd $2; find . -xdev -type f;); do
		case "$file" in
		./rom/note) ;; #nothing
		./etc/config*|\
		./usr/lib/opkg/info/*) cp -af $2/$file $file;;
		*) ln -sf /rom/${file#./*} $file;;
		esac
	done
	for file in $(cd $2; find . -xdev -type l;); do
		cp -af $2/${file#./*} $file
	done
	echo "done"
}

pivot() { # <new_root> <old_root>
	mount -o move /proc $1/proc && \
	pivot_root $1 $1$2 && {
		mount -o move $2/dev /dev
		mount -o move $2/tmp /tmp
		mount -o move $2/sys /sys 2>&-
		mount -o move $2/overlay /overlay 2>&-
		return 0
	}
}

fopivot() { # <rw_root> <ro_root> <dupe?>
	root=$1
	{
		if grep -q overlay /proc/filesystems; then
			mount -t overlayfs -olowerdir=/,upperdir=$1 "overlayfs:$1" /mnt && root=/mnt
		elif grep -q mini_fo /proc/filesystems; then
			mount -t mini_fo -o base=/,sto=$1 "mini_fo:$1" /mnt 2>&- && root=/mnt
		else
			mount --bind / /mnt
			mount --bind -o union "$1" /mnt && root=/mnt 
		fi
	} || {
		[ "$3" = "1" ] && {
		mount | grep "on $1 type" 2>&- 1>&- || mount -o bind $1 $1
		dupe $1 $rom
		}
	}
	pivot $root $2
}

ramoverlay() {
	mkdir -p /tmp/root
	mount -t tmpfs -o mode=0755 root /tmp/root
	fopivot /tmp/root /rom 1
}