#!/bin/bash

# Copyright 2024  Patrick J. Volkerding, Sebeka, Minnesota, USA
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# This script removes initrds in the /boot directory if there's no kernel
# in /boot with the same version. This keeps unused initrds from accumulating
# and filling up the filesystem.

# Usage: Run without any options to clean up initrd orphans:
#
# ./remove-orphaned-initrds
#
# To see what would be removed without actually removing anything:
#
# ./remove-orphaned-initrds --dry-run
#
# This script is suitable to run as a periodic cron job (perhaps weekly).

ORPHANS_FOUND=false

cd /boot
for initrd in initrd-*.img ; do
  if [ ! -r $initrd ]; then
    continue
  fi
  # We are not removing symlinks here. We'll remove dangling ones later on.
  if [ -L $initrd ]; then
    continue
  fi
  # Find the identifying portion of the initrd's filename:
  IDENTIFIER="$(basename $(echo $initrd | cut -f 2- -d -) .img)"
  if [ ! -r vmlinuz-${IDENTIFIER} ]; then
    ORPHANS_FOUND=true
    if [ "$1" = "--dry-run" ]; then
      echo "Would remove orphaned initrd: /boot/${initrd}"
    else
      echo "Removing orphaned initrd: /boot/${initrd}"
      rm -f $initrd
    fi
  fi
done
if [ "$ORPHANS_FOUND" = "false" ]; then
  echo "No orphaned initrds found in /boot."
fi
# Also handle initrd symlinks:
if [ "$1" = "--dry-run" ]; then
  for dangling_symlink in $(find . -name "initrd-*.img" -type l -printf '%P\n') $(find . -name "initrd.gz" -type l -printf '%P\n') ; do
    if [ ! -r "$(readlink $dangling_symlink)" ]; then
      echo "Would remove dangling initrd symlink: /boot/${dangling_symlink}"
    else
      IDENTIFIER="$(basename $(echo $(readlink $dangling_symlink) | cut -f 2- -d -) .img)"
      if [ ! -r vmlinuz-${IDENTIFIER} ]; then
        echo "Would remove dangling initrd symlink: /boot/${dangling_symlink}"
      fi
    fi
  done
else
  for dangling_symlink in $(find . -name "initrd-*.img" -xtype l -printf '%P\n') $(find . -name "initrd.gz" -xtype l -printf '%P\n') ; do
    echo "Removing dangling initrd symlink: /boot/${dangling_symlink}"
    rm -f $dangling_symlink
  done
fi