arch-freeze-kernel-modules

#!/usr/bin/env ruby

#
# Freeze Kernel Modules (Arch Boot Maintenance Script) by epitron
#
# Purpose: When you upgrade the kernel in Arch, this script will ensure that the old kernel modules
#          don't get deleted, allowing the system to keep fuctioning normally until the next reboot,
#          at which time the old modules will be removed.
#
# Usage: Run this script as root when the machine starts.
#


#
# Verbosely run a shell command
# (Prints the command it runs, and if there's an error, it tells the user and terminates the script.)
#
def cmd(*args)
  puts "    => #{args.join(" ")}"
  print "       "

  unless system(*args)
    $stderr.puts "[!] Command exited with error (may not be fatal)"
  end
end


# Make sure the script is running as root
if Process.uid != 0
  $stderr.puts "[!] Error: This script must be run as the root user."
  exit 1
end


Dir.chdir("/lib/modules")


# Detect new and old kernel module directories
everything      = Dir["*"]
extra_modules   = Dir["extramodules-*"]
current_modules = Dir["extramodules-*/version"].map { |v| File.read(v).strip }
old_modules     = everything - (current_modules + extra_modules)

# Make sure the current kernel modules directories are present!
current_modules.each do |k|
  unless File.directory? k
    $stderr.puts "[!] Error: The modules directory /lib/modules/#{k} is missing. Something has gone awry; please investigate."
    exit 1
  end
end

# Unprotect and remove the old module dirs
if old_modules.any?
  puts "[*] Removing old kernel modules:"
  cmd("chattr", "-R", "-i", *old_modules)
  cmd("rm", "-rf", *old_modules)
end

# Protect the new module dirs
if current_modules.any?
  puts "[*] Protecting new kernel modules:"
  cmd("chattr", "-R", "+i", *current_modules)
end