# Copyright (c) 2012 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.

description     "Preload network drivers"
author          "chromium-os-dev@chromium.org"

# Run on boot-services; "stay running" until the udev-trigger completes
# (which is guaranteed to happen after boot-services)
start on starting boot-services
stop on stopped udev-trigger

env drvfile=/var/lib/preload-network-drivers

pre-start script
  # If the drivers for Ethernet or WiFi devices are modules, our post-stop
  # script will have recorded the driver names on the previous boot cycle.
  # Load those drivers now so shill can config the network sooner,
  # ideally by the time login screen is up.
  #
  # Note: failure to probe the module here is NOT fatal.
  if [ -s $drvfile ] ; then
    for drv in $(head -1 $drvfile); do
      if ! modprobe "$drv" >/dev/null 2>&1 ; then
        # If modprobe didn't like the alias file for some reason, just
        # move it out of the way.  The post-stop script will make a new
        # one.
        mv $drvfile $drvfile.bad
        logger -t "$UPSTART_JOB" \
          "modprobe $drv failed.  Renamed $drvfile with .bad suffix."
      fi
    done
  fi
end script

post-stop script
  # Create/Update driver names for the Ethernet and WiFi drivers.
  # Used to preload Ethernet and WiFi drivers in pre-start script.
  # TODO(ggg): can shill share the "user selected" network device?

  newdrv=''
  for dev in eth0 wlan0 mlan0; do
    # Get the module name
    mod_link="/sys/class/net/${dev}/device/driver/module"
    if [ -e "$mod_link" ]; then
      drvmod=$(basename $(readlink "$mod_link"))
    else
      continue
    fi

    if [ -n "$newdrv" ] ; then
      newdrv="$drvmod $newdrv"
    else
      newdrv="$drvmod"
    fi
  done

  if [ -s $drvfile ] ; then
    olddrv=$(head -1 $drvfile)
  fi

  # Only update contents if they've changed.
  if [ "$newdrv" != "$olddrv" ] ; then
    echo "$newdrv" > $drvfile
  fi
end script