cdist/hacking/v3-busybox/init
Nico Schottelius 50bca7891f preos 0.4
Signed-off-by: Nico Schottelius <nico@wurzel.schottelius.org>
2015-05-19 11:39:39 +02:00

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#!/bin/sh
#Create all the symlinks to /bin/busybox
/bin/busybox --install -s
#Mount things needed by this script
mount -t proc proc /proc
mount -t sysfs sysfs /sys
#Disable kernel messages from popping onto the screen
echo 0 > /proc/sys/kernel/printk
#Create device nodes
mknod /dev/null c 1 3
mknod /dev/tty c 5 0
mdev -s
#Function for parsing command line options with "=" in them
# get_opt("init=/sbin/init") will return "/sbin/init"
get_opt() {
echo "$@" | cut -d "=" -f 2
}
#Defaults
init="/sbin/init"
root="/dev/hda1"
#Process command line options
for i in $(cat /proc/cmdline); do
case $i in
root\=*)
root=$(get_opt $i)
;;
init\=*)
init=$(get_opt $i)
;;
esac
done
exec sh
# Skipping the rest
#Mount the root device
mount "${root}" /newroot
#Check if $init exists and is executable
if [[ -x "/newroot/${init}" ]] ; then
#Unmount all other mounts so that the ram used by
#the initramfs can be cleared after switch_root
umount /sys /proc
#Switch to the new root and execute init
exec switch_root /newroot "${init}"
fi
#This will only be run if the exec above failed
echo "Failed to switch_root, dropping to a shell"
exec sh