#!/bin/sh
### BEGIN INIT INFO
# Provides:          grml-udev
# Required-Start:    mountkernfs
# Required-Stop:
# Should-Start:
# Should-Stop:
# Default-Start:     S
# Default-Stop:
# Short-Description: wrapper around udev to support bootoptions noudev and blacklist
### END INIT INFO

. /lib/lsb/init-functions

# 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
}

# are we running within init (non_interactive) or within shell (interactive)?
check_for_non_interactive() {
  if [ "$RUNLEVEL" = "S" -a "$PREVLEVEL" = "N" ]; then
    return
  fi

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

  return 1
}

# start init script through official Debian way
udev_exec() {
  # avoid syntax error if called without valid parameter:
  [ -z "$1" ] && exec /etc/init.d/udev "$1"

  exec /etc/init.d/udev "$1"
}

# test whether udev is enabled in init's configuration
udev_active() {
  # file-rc:
  if [ -r /etc/runlevel.conf ] && egrep -q '^[0-9]+.*-.*-.*\/etc\/init.d\/udev$' /etc/runlevel.conf ; then
    return 0
  fi

  # sysv-rc:
  if ls /etc/rcS.d/*udev >/dev/null 2>&1 ; then
    return 0
  fi

  return 1
}

# if original udev init script is enabled to not execute our script
udev_init_check() {
  if udev_active ; then
    log_warning_msg "Original udev init script is configured for startup, ignoring request to start $0"
    return 1
  fi
}

case "$1" in
  start)
        # do not flood console with kernel driver messages
        # grep -q debug /proc/cmdline || echo 0 > /proc/sys/kernel/printk

        # do not display anything when bootoption *splash is present:
        # if grep -qe ' splash' -qe ' tsplash' -qe ' textsplash' /proc/cmdline ; then
        #   exec >/dev/null </dev/null
        # fi

        # support bootoption blacklist, must be executed *before* udev is present
        if [ -r /etc/grml/autoconfig.functions ] ; then
          ( zsh -c '. /etc/grml/autoconfig.functions && config_blacklist || printf "Error when trying to run config_blacklist.\n">&2' )
        else
          printf 'Warning: /etc/grml/autoconfig.functions could not be read.\n'>&2
        fi

        # support bootoption noudev and inform user how to skip
        # execution of udev (being bootoption noudev)
        if ! grep -q noudev /proc/cmdline ; then
          check_for_non_interactive && \
            log_action_msg "If your system hangs now, disable udev with bootoption \"noudev\"" && echo
        else
           # - allow execution of initscript through FORCE=1 when booting with noudev
           if [ -z "$FORCE" ] ; then
              log_failure_msg "Bootoption \"noudev\" found. Skipping execution of udev init script."
              if ! check_for_non_interactive ; then
                 printf "\nIt has been detected that the udev init script\n"
                 printf "has been run from an interactive shell.\n"
                 printf "You booted your system using bootoption noudev.\n"
                 printf "To force startup of udev please run:\n\n"
                 printf "\tFORCE=1 Start udev\n\n"
              fi
              exit 1
           fi
        fi

        udev_init_check && udev_exec start

        ;;

  # in any other situation just directly invoke udev:
  *)
        udev_init_check && udev_exec "$1"
        ;;
esac

exit 0

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