source: pkg/main/initramfs-tools/trunk/debian/initramfs-tools.preinst @ 2179

#!/bin/sh

set -e

chrooted() {
        # borrowed from udev's postinst
        if [ "$(stat -c %d/%i /)" = "$(stat -Lc %d/%i /proc/1/root 2>/dev/null)" ]; then
                # the devicenumber/inode pair of / is the same as that of
                # /sbin/init's root, so we're *not* in a chroot and hence
                # return false.
                return 1
        fi
        return 0
}

case "$1" in
        install)
                mkdir -p /etc/initramfs-tools/conf.d

                # First time install.  Can we autodetect the RESUME partition?
                if [ -r /proc/swaps ]; then
                        RESUME=$(tail -n $(($(wc -l /proc/swaps | awk ' { print $1 } ') - 1)) /proc/swaps | sort -rk3 | head -n 1 | awk ' { print $1 } ')
                fi

                # Inherit initrd-tools settings if possible.
                if [ -e /etc/mkinitrd/mkinitrd.conf ]; then
                         . /etc/mkinitrd/mkinitrd.conf
                fi
                # write conf.d/resume if not in a chroot
                if [ -n "${RESUME}" ] && ! chrooted; then
                        echo "RESUME=${RESUME}" > /etc/initramfs-tools/conf.d/resume
                fi

                # Add initrd-tools modules, while trying to minimize prompting
                if [ -e /etc/mkinitrd/modules ]; then
                        cp /etc/mkinitrd/modules /etc/initramfs-tools/
                        sed -i \
                          -e 's/\/etc\/mkinitrd\/modules: Kernel modules to load for initrd./List of modules that you want to include in your initramfs./g' \
                          -e 's/mkinitrd/update-initramfs/g' \
                          -e '/# This file should/,/one per line\./d' \
                          -e 's/Comments begin with.*/Syntax:  module_name [args ...]/' \
                          -e 's/^#  ext2$/# raid1/' \
                          -e 's/^#  wd io=0x300$/# sd_mod/' \
                          -e '/^ide-generic/d' \
                          -e '/^ide-disk/d' \
                          -e '/^ext2/d' \
                          -e '/^ext3/d' \
                          /etc/initramfs-tools/modules
                fi

                if [ -e /etc/mkinitrd/DSDT ]; then
                        cp /etc/mkinitrd/DSDT /etc/initramfs-tools/DSDT.aml
                fi
        ;;
esac

#DEBHELPER#