#!/bin/sh -e

PATH="/sbin:/bin"

# defaults
tmpfs_size="5M"
udev_root="/dev/"

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

. /etc/udev/udev.conf
. /lib/lsb/init-functions

case "$(uname -r)" in
  2.[012345].*|2.6.[0-7]|2.6.[0-7][!0-9]*)
    log_failure_msg "udev requires a kernel >= 2.6.8, not started."
    exit 0
    ;;
esac

if ! grep -q '[[:space:]]tmpfs$' /proc/filesystems; then
  log_failure_msg "udev requires tmpfs support, not started."
  exit 0
fi

if [ ! -e /proc/sys/kernel/hotplug ]; then
  log_failure_msg "udev requires hotplug support, not started."
  exit 0
fi

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

# 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 0
  fi

  # /.dev is used by /sbin/MAKEDEV to access the real /dev directory.
  # if you don't like this, remove /.dev/.
  [ -d /.dev ] && mount -n --bind /dev /.dev

  log_begin_msg "Mounting a tmpfs over /dev..."
  mount -n -o size=$tmpfs_size,mode=0755 -t tmpfs none /dev
  log_end_msg $?

  # Using ln to test if /dev works, because touch is in /usr/bin/
  if ln -s test /dev/test-file; then
    rm /dev/test-file
  else
    echo " FAILED!"
    echo "Not enabling udev because the system lacks tmpfs support!"
    umount /dev || true
    exit 1
  fi
}

# I hate this hack.  -- Md
make_extra_nodes() {
  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/$name ;;
      M) mknod --mode=600 /dev/$name $arg1 ;;
      *) log_warning_msg "links.conf: unparseable line ($type $name $arg1)" ;;
    esac
  done
}

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

if [ "$udev_root" != "/dev/" ]; then
  log_warning_msg "WARNING: udev_root != /dev/"

case "$1" in
  start)
    if [ -e "$udev_root/.udevdb" ]; then
      if mountpoint -q /dev/; then
        log_failure_msg "FATAL: udev is already active on $udev_root."
        exit 1
      else
        log_warning_msg "WARNING: .udevdb already exists on the old $udev_root!"
      fi
    fi
    mount -n -o size=$tmpfs_size,mode=0755 -t tmpfs none $udev_root
    log_begin_msg "Creating initial device nodes..."
    udevstart
    log_end_msg $?
    ;;
  stop)
    start-stop-daemon --stop --exec /sbin/udevd --oknodo --quiet
    log_begin_msg "Unmounting $udev_root..."
    # unmounting with -l should never fail
    if umount -l $udev_root; then
      log_end_msg 0
    else
      log_end_msg 1
    fi
    ;;
  restart|force-reload)
    $0 stop
    $0 start
    ;;
  *)
    log_success_msg "Usage: /etc/init.d/udev {start|stop|restart|force-reload}"
    exit 1
    ;;
esac

  exit 0
fi # udev_root != /dev/

##############################################################################
# When modifying this script, do not forget that between the time that
# the new /dev has been mounted and udevstart 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/.udevdb" ]; then
      if mountpoint -q /dev/; then
        log_failure_msg "FATAL: udev is already active on $udev_root."
        exit 1
      else
        log_warning_msg "WARNING: .udevdb already exists on the old $udev_root!"
      fi
    fi
    unmount_devpts
    mount_tmpfs
    [ -d /proc/1 ] || mount -n /proc
    log_begin_msg "Creating initial device nodes..."
    echo "/sbin/udevsend" > /proc/sys/kernel/hotplug
    udevstart
    log_end_msg $?
    make_extra_nodes
    # some other packages depend on the presence of this file
    : > /dev/.udev.tdb
    ;;
  stop)
    start-stop-daemon --stop --exec /sbin/udevd --oknodo --quiet
    unmount_devpts
    log_begin_msg "Unmounting /dev..."
    # unmounting with -l should never fail
    if umount -l /dev; then
      log_end_msg 0
      umount -l /.dev || true
      /etc/init.d/mountvirtfs start
    else
      log_end_msg 1
    fi
    ;;
  restart|force-reload)
    start-stop-daemon --stop --exec /sbin/udevd --oknodo --quiet
    log_begin_msg "Recreating device nodes..."
    echo "/sbin/udevsend" > /proc/sys/kernel/hotplug
    udevstart
    make_extra_nodes
    log_end_msg $?
    ;;
  *)
    echo "Usage: /etc/init.d/udev {start|stop|restart|force-reload}"
    exit 1
    ;;
esac

exit 0

