#!/bin/ash mknod /dev/ttyprintk c 5 3 echo "hello world" > /dev/ttyprintk # Setup our path export PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin # 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 2>/dev/ttyprintk mount /proc 2>/dev/ttyprintk mount /sys 2>/dev/ttyprintk mount /sys/firmware/efi/efivars # Setup the pty psudeo filesystem mkdir /dev/pts mount /dev/pts 2>/dev/ttyprintk if [ ! -r /dev/ptmx ]; then ln -s /dev/pts/ptmx /dev/ptmx fi # bring up the ethernet; maybe should do DHCP? ifconfig lo 127.0.0.1 if [ -f /lib/modules/e1000.ko ]; then insmod /lib/modules/e1000.ko ifconfig eth0 10.0.2.15 # qemu ifconfig eth0 > /dev/ttyprintk # Setup the ssh server, allow root logins and log to stderr if [ ! -d /etc/dropbear ]; then mkdir /etc/dropbear fi dropbear -B -R 2>/dev/ttyprintk ifconfig eth0 | head -1 > /dev/tty0 fi # Recovery shells will erase anything from here mkdir -p /tmp/secret # Now it is safe to print a banner if [ -r /etc/motd ]; then cat /etc/motd cat /etc/motd > /dev/tty0 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