OpenWrt switch to ramfs

pivot_services.sh

#!/bin/sh

. /lib/functions.sh
. /lib/functions/system.sh

kill_remaining() { # [ <signal> [ <loop> ] ]
	local loop_limit=10

	local sig="${1:-TERM}"
	local loop="${2:-0}"
	local run=true
	local stat

	echo -n "Sending $sig to remaining processes ... "

	while $run; do
		run=false
		for stat in /proc/[0-9]*/stat; do
			[ -f "$stat" ] || continue

			local pid name state ppid rest
			read pid name state ppid rest < $stat
			name="${name#(}"; name="${name%)}"

			# Skip PID1, ourself and our children
			[ $pid -ne 1 -a $pid -ne $$ -a $ppid -ne $$ ] || continue

			local cmdline
			read cmdline < /proc/$pid/cmdline

			# Skip kernel threads
			[ -n "$cmdline" ] || continue

			echo -n "$name "
			kill -$sig $pid 2>/dev/null

			[ $loop -eq 1 ] && run=true
		done

		let loop_limit--
		[ $loop_limit -eq 0 ] && {
			echo
			echo "Failed to kill all processes."
			exit 1
		}
	done
	echo
}


killall -9 telnetd
killall -9 dropbear
killall -9 ash

kill_remaining TERM
sleep 3
kill_remaining KILL 1

for service in /etc/init.d/*; do
	$service stop
done

/etc/init.d/network restart
/etc/init.d/dropbear restart

remount_ro.sh

#!/bin/sh

set -e

mount -o remount,ro overlayfs:/overlay
mount -o remount,ro /overlay
mount -o remount,ro /dev/root

switch_to_ramfs.sh

#!/bin/ash

set -e

mkdir -p /newroot

mount -t tmpfs -o size=32m none /newroot

cp -rp /etc /lib /usr /root /www /bin /sbin /newroot

rm -f /newroot/var
ln -s /tmp /newroot/var


mkdir /newroot/oldroot

mkdir /newroot/proc
mount -o noatime,move /proc /newroot/proc
pivot_root /newroot /newroot/oldroot

mkdir -p /sys
mount -o noatime,move /oldroot/sys /sys
mkdir -p /dev
mount -o noatime,move /oldroot/dev /dev
mkdir -p /tmp
mount -o noatime,move /oldroot/tmp /tmp
mkdir -p /overlay
mount -o noatime,move /oldroot/overlay /overlay