mkinitcpio-multiflash.install

#!/bin/bash

_MKINITCPIO_CFG='/etc/mkinitcpio.conf'

_CMDLINE_CFG='/boot/cmdline.txt'
_CMD_CFG='multiflash'
_IP_CMD_CFG='ip=:::::eth0:dhcp'

_CONFIG_CFG='/boot/config.txt'
_INITRAMFS='initramfs.img'
_INITRAMFS_CFG="initramfs $_INITRAMFS followkernel"
_INITRAMFS_PATH="/boot/$_INITRAMFS"

#=====================================================================
# Checks for a hook name in a given configuration file.
# Arguments: hook name, configuration file
# Example: _has_hook my-hook /etc/mkinitcpio.conf
#=====================================================================
_has_hook() {
  local hook_name=$1
  local config_file=$2
  grep -qe "^HOOKS=\".*$hook_name" $config_file
  if (($? == 1)); then
    return 1
  fi
  return 0
}

#=====================================================================
# Adds a hook name to a given configuration file.
# Arguments: hook name, configuration file
# Example: _add_hook my-hook /etc/mkinitcpio.conf
#=====================================================================
_add_hook() {
  local hook_name=$1
  local config_file=$2
  sed -i "s|^\(HOOKS=\".*\)\"|\1 $hook_name\"|g" $config_file
}

#=====================================================================
# Removes a hook name from a given configuration file.
# Arguments: hook name, configuration file
# Example: _remove_hook my-hook /etc/mkinitcpio.conf
#=====================================================================
_remove_hook() {
  local hook_name=$1
  local config_file=$2
  sed -i "s|^\(HOOKS=\".*\)\( $hook_name\)\"|\1\"|g" $config_file
}

#=====================================================================
# Checks for a configuration option in a given configuration file.
# Arguments: configuration option, configuration file
# Example: _has_cfg my-cfg=value /boot/config.txt
#=====================================================================
_has_cfg() {
  local cfg="$1"
  local config_file=$2
  grep -qe ".*$cfg" $config_file
  if (($? == 1)); then
    return 1
  fi
  return 0
}

#=====================================================================
# Appends the ip kernel argument to a given command line file.
# Arguments: ip kernel argument, configuration file
# Example: _add_ip ip=dhcp /boot/cmdline.txt
#=====================================================================
_add_ip() {
  local ip_cfg=$1
  local config_file=$2
  sed -i "s|$| $ip_cfg|" $config_file
}

#=====================================================================
# Removes the ip kernel argument from a given command line file.
# Arguments: ip kernel argument, configuration file
# Example: _remove_ip ip=dhcp /boot/cmdline.txt
#=====================================================================
_remove_ip() {
  local ip_cfg=$1
  local config_file=$2
  sed -i "s| $ip_cfg||" $config_file
}

#=====================================================================
# Adds the initramfs config to a given config line file.
# Arguments: initramfs config, configuration file
# Example: _add_initramfs 'initramfs initramfs.img' config.txt
#=====================================================================
_add_initramfs() {
  local initramfs_cfg="$1"
  local config_file=$2
  echo "$initramfs_cfg" >> $config_file
}

#=====================================================================
# Removes the initramfs config from a given config line file.
# Arguments: initramfs config, configuration file
# Example: _remove_initramfs 'initramfs initramfs.img' config.txt
#=====================================================================
_remove_initramfs() {
  local initramfs_cfg="$1"
  local config_file=$2
  sed -i "/^$initramfs_cfg/d" $config_file
}

#=====================================================================
# Install scripts.
#=====================================================================

post_install() {
  post_upgrade "${@}";
}

post_upgrade() {

  # Check mkinitcpio hooks.
  for hook in net multiflash; do
    if ! _has_hook $hook $_MKINITCPIO_CFG; then
      _add_hook $hook $_MKINITCPIO_CFG
      cat <<MSG
>>> Adding hook to $_MKINITCPIO_CFG:
    > HOOKS="[...] $hook"
MSG
    fi
  done

  # Check ip kernel command line argument.
  if ! _has_cfg $_IP_CMD_CFG $_CMDLINE_CFG; then
    _add_ip $_IP_CMD_CFG $_CMDLINE_CFG
    cat <<MSG
>>> Adding ip kernel argument to $_CMDLINE_CFG:
    > [...] $_IP_CMD_CFG
MSG
  fi

  # Check initramfs bootloader configuration.
  if ! _has_cfg "$_INITRAMFS_CFG" $_CONFIG_CFG; then
    _add_initramfs "$_INITRAMFS_CFG" $_CONFIG_CFG
    cat <<MSG
>>> Adding initramfs config to $_CONFIG_CFG:
    > $_INITRAMFS_CFG
MSG
  fi

  # Prompt for additional kernel command line argument.
  grep -qe ".*$_CMD_CFG" $_CMDLINE_CFG || cat <<MSG
>>> [INFO] Add kernel argument '$_CMD_CFG' to $_CMDLINE_CFG:
    > [...] $_CMD_CFG=[...]
MSG

  # Try to generate initramfs image.
  cat <<MSG
>>> Generating initramfs at $_INITRAMFS_PATH:
    > mkinitcpio -k $(ls /lib/modules | grep ARCH) -g $_INITRAMFS_PATH ...
MSG
  mkinitcpio -k $(ls /lib/modules | grep ARCH) -g $_INITRAMFS_PATH

  # Enable service.
  systemctl enable mkinitcpio-multiflash
  systemctl start mkinitcpio-multiflash
}

post_remove() {

  # Try to remove initramfs image.
  if [ -f $_INITRAMFS_PATH ]; then
    cat <<MSG
>>> Removing initramfs $_INITRAMFS_PATH ...
MSG
    rm -f $_INITRAMFS_PATH
  fi

  # Prompt to remove kernel command line argument.
  cat <<MSG
>>> [INFO] Remove kernel argument '$_CMD_CFG' from $_CMDLINE_CFG:
    > [...] $_CMD_CFG=[...]
MSG

  # Remove initramfs bootloader configuration.
  if _has_cfg "$_INITRAMFS_CFG" $_CONFIG_CFG; then
    _remove_initramfs "$_INITRAMFS_CFG" $_CONFIG_CFG
    cat <<MSG
>>> Removing initramfs config from $_CONFIG_CFG:
    > $_INITRAMFS_CFG
MSG
  fi

  # Remove ip kernel command line argument.
  if _has_cfg $_IP_CMD_CFG $_CMDLINE_CFG; then
    _remove_ip $_IP_CMD_CFG $_CMDLINE_CFG
    cat <<MSG
>>> Removing ip kernel argument from $_CMDLINE_CFG:
    > [...] $_IP_CMD_CFG
MSG
  fi

  # Remove mkinitcpio hooks.
  for hook in multiflash net; do
    if _has_hook $hook $_MKINITCPIO_CFG; then
      _remove_hook $hook $_MKINITCPIO_CFG
  cat <<MSG
>>> Removing hook from $_MKINITCPIO_CFG:
    > HOOKS="[...] $hook"
MSG
    fi
  done

  # Disable service.
  systemctl stop mkinitcpio-multiflash
  systemctl disable mkinitcpio-multiflash
}