init

#!/bin/sh

# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
# /init script for use in factory install shim.  Requires busybox in
# /bin/busybox, and a symlink from /bin/sh -> busybox.

# Mount point for the new tmpfs based partition.
NEWROOT_MNT=/newroot
# SD card partition and mount point.
# TODO(girts): find it, instead of hardcoding.
SD_DEV=/dev/sdb3
SD_MNT=/sdcard
# Size of the root ramdisk.
TMPFS_SIZE=300M

initial_mounts() {
  mkdir /proc /sys /tmp /etc "$SD_MNT" "$NEWROOT_MNT"
  mount -n -t proc proc /proc
  mount -n -t sysfs sysfs /sys
  mount -n -t devtmpfs -o mode=0755,size=20M none /dev
  mkdir -p /dev/shm /dev/pts
  mount -n -t tmpfs -onosuid,nodev shmfs /dev/shm
  mount -n -t devpts -onoexec,nosuid,gid=5,mode=0620 devpts /dev/pts

  # Create symlinks for all busybox programs.  /proc needs to be mounted first,
  # otherwise it will mess up the link.
  busybox --install -s
}

drop_to_shell() {
  echo "Dropping to shell..."
  exec /bin/sh
}

wait_for_root() {
  local try
  echo -n "Waiting for $SD_DEV to appear"
  for try in $(seq 20); do
    echo -n "."
    if [ -b "$SD_DEV" ]; then
      echo "ok"
      return 0
    fi
    sleep 1
  done
  echo
  echo "Failed waiting for root!"
  return 1
}

mount_sd_card() {
  local try
  echo -n "Mounting sd card"
  for try in $(seq 20); do
    echo -n "."
    if mount "$SD_DEV" "$SD_MNT" -o ro; then
      echo "ok"
      return 0
    fi
    sleep 1
  done
  echo
  echo "Failed to mount sd card!"
  return 1
}

mount_tmpfs() {
  echo "Mounting tmpfs..."
  mount -t tmpfs tmpfs "$NEWROOT_MNT" -o "size=$TMPFS_SIZE"
  return $?
}

copy_contents() {
  echo "Copying sdcard->tmpfs..."
  time cp -av "$SD_MNT"/* "$NEWROOT_MNT"
  return $?
}

move_mounts() {
  mount --move /proc "$NEWROOT_MNT/proc"
  mount --move /dev "$NEWROOT_MNT/dev"
  mount --move /sys "$NEWROOT_MNT/sys"
}

unmount_sd_card() {
  umount "$SD_MNT"
  local try
  echo -n "$SD_DEV can now be safely removed"
  for try in $(seq 5); do
    echo -n "."
    sleep 1
  done
  echo "continue"
  return 0
}

main() {
  echo Starting init...
  PATH=/bin

  initial_mounts
  wait_for_root || drop_to_shell
  mount_sd_card || drop_to_shell
  mount_tmpfs || drop_to_shell
  copy_contents || drop_to_shell
  unmount_sd_card || drop_to_shell
  move_mounts || drop_to_shell
  # switch_root makes a safety check for existance of /init.  Make it happy.
  touch /init
  # /sbin/chromeos_startup will see this and skip mounting of sysfs, proc and
  # /dev.
  mkdir "$NEWROOT_MNT/dev/.initramfs"
  # Chroot into newroot, erase the contents of the old /, and exec real init.
  exec switch_root "$NEWROOT_MNT" /sbin/init
  # This should not really happen.
  echo "Failed to switch root"
  drop_to_shell
}

main