#!/bin/ash
# This is the very first script invoked by the Linux kernel and is
# running out of the ram disk.  There are no fileysstems mounted.
# It is important to have a way to invoke a recovery shell in case
# the boot scripts are messed up, but also important to modify the
# PCRs if this happens to prevent the TPM disk keys from being revealed.

# First thing it is vital to mount the /dev and other system directories
mkdir /proc /sys /dev /tmp /boot /media 2>&- 1>&-
mount /dev
mount /proc
mount /sys

# Recovery shells will erase anything from here
mkdir -p /tmp/secret

# Setup our path
export PATH=/sbin:/bin

# Now it is safe to print a banner
if [ -r /etc/motd ]; then
	cat /etc/motd
fi

# Load the date from the hardware clock, setting it in local time
hwclock -l -s

# Read the system configuration parameters
. /etc/functions
. /etc/config

# Add our boot devices into the /etc/fstab, if they are defined
# in the configuration file.
if [ ! -z "$CONFIG_BOOT_DEV" ]; then
	echo >> /etc/fstab "$CONFIG_BOOT_DEV /boot auto defaults,ro 0 0"
fi
if [ ! -z "$CONFIG_USB_BOOT_DEV" ]; then
	echo >> /etc/fstab "$CONFIG_USB_BOOT_DEV /media auto defaults,ro 0 0"
fi

if [ ! -x "$CONFIG_BOOTSCRIPT" ]; then
	recovery 'Boot script missing?  Entering recovery shell'
	# just in case...
	tpm extend -ix 4 -ic recovery
	exec /bin/ash
fi

# If the user has been holding down r, enter a recovery shell
# otherwise immediately start the configured boot script.
# We don't print a prompt, since this is a near instant timeout.
read \
	-t 0.1 \
	-n 1 \
	boot_option
echo

if [ "$boot_option" = "r" ]; then
	# Start an interactive shell
	recovery 'User requested recovery shell'
	# just in case...
	tpm extend -ix 4 -ic recovery
	exec /bin/ash
fi

echo '***** Normal boot:' $CONFIG_BOOTSCRIPT
exec "$CONFIG_BOOTSCRIPT"

# We should never reach here, but just in case...
recovery 'Boot script failure?  Entering recovery shell'
# belts and suspenders, just in case...
tpm extend -ix 4 -ic recovery
exec /bin/ash