#!/bin/sh -e
### BEGIN INIT INFO
# Provides:          udev
# Required-Start:    mountvirtfs 
# Required-Stop:     
# Default-Start:     S
# Default-Stop:
# Short-Description: Start udevd, populate /dev and load drivers.
### END INIT INFO

# we need to unmount /dev/pts/ and remount it later over the tmpfs
unmount_devpts() {
  if mountpoint -q /dev/pts/; then
    umount -l /dev/pts/
  fi

  if mountpoint -q /dev/shm/; then
    umount -l /dev/shm/
  fi
}

# mount a tmpfs over /dev, if somebody did not already do it
mount_tmpfs() {
  if grep -E -q "^[^[:space:]]+ /dev tmpfs" /proc/mounts; then
    return
  fi

  # /dev/.static/dev/ is used by MAKEDEV to access the real /dev/ directory.
  # /etc/udev/ is recycled as a temporary mount point because it's the only
  # directory which is guaranteed to be available.
  mount -n -o bind /dev /etc/udev

  if ! mount -n -o size=$tmpfs_size,mode=0755 -t tmpfs tmpfs /dev; then
    umount /etc/udev
    echo "udev requires tmpfs support, not started."
    exit 1
  fi

  mkdir -p /dev/.static/dev
  chmod 700 /dev/.static/
  # The mount options in busybox are non-standard...
  if test -x /bin/mount.util-linux
  then
    /bin/mount.util-linux --move /etc/udev /dev/.static/dev
  elif test -x /bin/busybox
  then
    busybox mount -n -o move /etc/udev /dev/.static/dev
  else
    echo "udev requires an identifiable mount command, not started."
    umount /etc/udev
    umount /dev
    exit 1
  fi
}

# I hate this hack.  -- Md
make_extra_nodes() {
  if [ "$(echo /lib/udev/devices/*)" != "/lib/udev/devices/*" ]; then
    cp -a /lib/udev/devices/* /dev/
  fi

  [ -e /etc/udev/links.conf ] || return 0
  grep '^[^#]' /etc/udev/links.conf | \
  while read type name arg1; do
    [ "$type" -a "$name" -a ! -e "/dev/$name" -a ! -L "/dev/$name" ] ||continue
    case "$type" in
      L) ln -s $arg1 /dev/$name ;;
      D) mkdir -p /dev/$name ;;
      M) mknod -m 600 /dev/$name $arg1 ;;
      *) echo "links.conf: unparseable line ($type $name $arg1)" ;;
    esac
  done
}

supported_kernel() {
  case "$(uname -r)" in
    2.[012345].*|2.6.[0-9]|2.6.[0-9][!0-9]*) return 1 ;;
    2.6.1[01]|2.6.1[01][!0-9]*) return 1 ;;
  esac
  return 0
}

set_hotplug_handler() {
  case "$(uname -r)" in
    2.6.1[0-4]|2.6.1[0-4][!0-9]*) HANDLER='/sbin/udevsend' ;;
  esac
  echo $HANDLER > /proc/sys/kernel/hotplug
}

# shell version of /usr/bin/tty
my_tty() {
  [ -x /bin/readlink ] || return 0
  [ -e /proc/self/fd/0 ] || return 0
  readlink --silent /proc/self/fd/0 || true
}

warn_if_interactive() {
  if [ "$RUNLEVEL" = "S" -a "$PREVLEVEL" = "N" ]; then
    return
  fi

  TTY=$(my_tty)
  if [ -z "$TTY" -o "$TTY" = "/dev/console" ]; then
    return
  fi

  printf "\n\n\nIt has been detected that the command\n\n\t$0 $*\n\n"
  printf "has been run from an interactive shell.\n"
  printf "It will probably not do what you expect, so this script will wait\n"
  printf "60 seconds before continuing. Press ^C to stop it.\n"
  printf "RUNNING THIS COMMAND IS HIGHLY DISCOURAGED!\n\n\n\n"
  sleep 60
}

##############################################################################

PATH="/sbin:/bin:/usr/bin"

[ -x /sbin/udevd ] || exit 0

# defaults
tmpfs_size="10M"
udev_root="/dev"
udevd_timeout=30

. /etc/udev/udev.conf

if ! supported_kernel; then
  echo "udev requires a kernel >= 2.6.12, not started."
  exit 1
fi

if [ ! -e /proc/filesystems ]; then
  echo "udev requires a mounted procfs, not started."
  exit 1
fi

if ! grep -q '[[:space:]]tmpfs$' /proc/filesystems; then
  echo "udev requires tmpfs support, not started."
  exit 1
fi

if [ ! -d /sys/class/ ]; then
  echo "udev requires a mounted sysfs, not started."
  exit 1
fi

if [ ! -e /proc/sys/kernel/hotplug ]; then
  echo "udev requires hotplug support, not started."
  exit 1
fi

##############################################################################

# When modifying this script, do not forget that between the time that
# the new /dev has been mounted and udevsynthesize has been run there will be
# no /dev/null. This also means that you cannot use the "&" shell command.

case "$1" in
    start)
    if [ -e "$udev_root/.udev/" ]; then
	if mountpoint -q /dev/; then
	    TMPFS_MOUNTED=1
	else
	    echo ".udev/ already exists on the static $udev_root!"
	fi
    else
	warn_if_interactive
    fi

    echo "Starting the hotplug events dispatcher" "udevd"
    udevd --daemon

    set_hotplug_handler

    if [ -z "$TMPFS_MOUNTED" ]; then
	unmount_devpts
	mount_tmpfs
	[ -d /proc/1 ] || mount -n /proc
    fi

    # if this directory is not present /dev will not be updated by udev
    mkdir -p /dev/.udev/ /dev/.udev/db/ /dev/.udev/queue/ /dev/.udevdb/
    # /dev/null must be created before udevd is started
    make_extra_nodes

    echo "Synthesizing the initial hotplug events"
    udevsynthesize

    # wait for the udevd childs to finish
    echo "Waiting for /dev to be fully populated"
    while [ -d /dev/.udev/queue/ ]; do
	sleep 1
	udevd_timeout=$(($udevd_timeout - 1))
	if [ $udevd_timeout -eq 0 ]; then
	    # ps axf
	    break
	fi
    done
    if [ $udevd_timeout -eq 0 ]; then
	echo 'timeout'
    fi
    ;;

    stop)
    echo "Stopping the hotplug events dispatcher" "udevd"
    start-stop-daemon --stop --name udevd --quiet
    ;;

    restart|force-reload)
    echo "Stopping the hotplug events dispatcher" "udevd"
    if start-stop-daemon --stop --name udevd --quiet ; then
	exit 1
    fi

    echo "Starting the hotplug events dispatcher" "udevd"
    udevd --daemon
    ;;

    *)
    echo "Usage: /etc/init.d/udev {start|stop|restart|force-reload}"
    exit 1
    ;;
esac

exit 0

