openwrt/package/base-files/files/etc/preinit

#!/bin/sh
# Copyright (C) 2006 OpenWrt.org
export PATH=/bin:/sbin:/usr/bin:/usr/sbin
. /etc/diag.sh

failsafe_ip() {
	ifconfig $ifname 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255 up
}

failsafe() {
	[ -n "$ifname" ] && grep "$ifname" /proc/net/dev >/dev/null && {
		failsafe_ip
		netmsg 192.168.1.255 "Entering Failsafe!"
		telnetd -l /bin/login <> /dev/null 2>&1
	}
	lock /tmp/.failsafe
	ash --login
}

mount proc /proc -t proc
mount sysfs /sys  -t sysfs

size=$(awk '/MemTotal:/ {l=5242880;mt=($2*1024);print((s=mt/2)<l)?mt-l:s}' /proc/meminfo)
mount tmpfs /tmp -t tmpfs -o size=$size,nosuid,nodev,mode=1777

if grep devfs /proc/filesystems > /dev/null; then
	mount devfs /dev -t devfs
	M0=/dev/pty/m0
	M1=/dev/pty/m1
	HOTPLUG=/sbin/hotplug-call
else
	mount -t tmpfs tmpfs /dev -o size=512K
	mknod /dev/console c 5 1
	mkdir /dev/shm
	/sbin/hotplug2 --coldplug --set-rules-file /etc/hotplug2-init.rules
	/sbin/hotplug2 --no-coldplug --persistent --set-rules-file /etc/hotplug2-init.rules &
	M0=/dev/ptmx
	M1=/dev/ptmx
	HOTPLUG=
fi

mkdir -p /dev/pts /dev/shm
mount devpts /dev/pts -t devpts

# the shell really doesn't like having stdin/out closed
# that's why we use /dev/pty/m0 and m1 as replacement
# for /dev/console if there's no serial console available
dd if=/dev/console of=/dev/null bs=1 count=0 >/dev/null 2>/dev/null && {
	M0=/dev/console
	M1=/dev/console
}

exec <$M0 >$M1 2>&0

echo "- preinit -"
trap 'FAILSAFE=true' USR1
[ -e /etc/preinit.arch ] && . /etc/preinit.arch
set_state preinit
echo "$HOTPLUG" > /proc/sys/kernel/hotplug
eval ${FAILSAFE:+failsafe}
lock -w /tmp/.failsafe

if [ -z "$INITRAMFS" ]; then
	mount_root
	[ -f /sysupgrade.tgz ] && {
		echo "- config restore -"
		cd /
		mv sysupgrade.tgz /tmp
		tar xzf /tmp/sysupgrade.tgz
		rm -f /tmp/sysupgrade.tgz
		sync
	}

	echo "- init -"
	
	killall hotplug2
	exec /sbin/init
fi