void-packages/srcpkgs/initramfs-tools/files/docs/example_hook

#!/bin/sh
#
#
# This is an example hook script.  It will be run by 'mkinitramfs'
# when it creates the image.  It's job is to decide which files to
# install, then install them into the staging area, where the
# initramfs is being created.  This happens when a new 'linux-image'
# package is installed, or when the administrator runs 'mkinitramfs'
# by hand to update an initramfs image.
#
#  CONFDIR -- usually /etc/initramfs-tools, can be set on mkinitramfs
#		 command line.
#
#  DESTDIR -- The staging directory where we are building the image.
#
# see initramfs-tools(8)

#
# List the soft prerequisites here.  This is a space separated list of
# names, of scripts that are in the same directory as this one, that
# must be run before this one can be.
#
PREREQ=""

prereqs()
{
	echo "$PREREQ"
}

case $1 in
# get pre-requisites
prereqs)
	prereqs
	exit 0
	;;
esac


# You can do anything you need to from here on.
#

# Source the optional 'hook-functions' scriptlet, if you need the
# functions defined within it.  Read it to see what is available to
# you.  It contains functions for copying dynamically linked program
# binaries, and kernel modules into the DESTDIR.
#
. /usr/share/initramfs-tools/hook-functions


# If this hook script is a conffile (and thus stored in
# /etc/mkinitramfs/hooks), it must take care to do the right thing
# when the package containing it is removed but not purged.  There of
# course may be other reasons to have custom logic deciding what to
# install.  The version variable may be useful for this.
#
if command -v myprog >/dev/null 2>&1; then
	copy_exec /usr/bin/myprog usr/bin
fi

# To accompany this, there should usually be a script for inside the
# initramfs named something like:
#
#   "/etc/mkinitramfs/local-premount/myprog"
#
# ... and it should do what is necessary to have 'myprog' get run
# inside the early runtime environment.

exit 0