#!/bin/sh

# Repository: https://gitea.evolix.org/evolix/maj.sh/

# fork by reg from /etc/kernel/postinst.d/apt-auto-removal script

VERSION="21.06.3"

set -e

# shellcheck disable=SC2046
eval $(apt-config shell DPKG Dir::bin::dpkg/f)
DPKG="${DPKG:-/usr/bin/dpkg}"

# Detect which one of apt/aptitude we should use.
# shellcheck disable=SC2120
get_apt_binary() {
    root="${1:-}"
    # apt could be a Java binary...
    if [ -x "${root}/usr/bin/apt" ] && ! ${root}/usr/bin/apt --version 2>&1 | grep -q "javac"; then
        echo "apt"
    elif [ -x "${root}/usr/bin/aptitude" ]; then
        echo "aptitude"
    # Usually in containers
    else
        echo "apt-get"
    fi
}

listupgrade_state_dir="${listupgrade_state_dir:-/var/lib/listupgrade}"

APT=$(get_apt_binary)

list="$("${DPKG}" -l | awk '/^[ih][^nc][ ]+(linux|kfreebsd|gnumach)-image-[0-9]+\./ && $2 !~ /-dbg(:.*)?$/ && $2 !~ /-dbgsym(:.*)?$/ { print $2,$3; }' \
   | sed -e 's#^\(linux\|kfreebsd\|gnumach\)-image-##' -e 's#:[^:]\+ # #')"
debverlist="$(echo "${list}" | cut -d' ' -f 2 | sort --unique --reverse --version-sort)"

if [ -n "$1" ]; then
    installed_version="$(echo "$list" | awk "\$1 == \"$1\" { print \$2;exit; }")"
fi
unamer="$(uname -r | tr '[:upper:]' '[:lower:]')"
if [ -n "${unamer}" ]; then
    running_version="$(echo "${list}" | awk "\$1 == \"${unamer}\" { print \$2;exit; }")"
fi
# ignore the currently running version if attempting a reproducible build
if [ -n "${SOURCE_DATE_EPOCH}" ]; then
    unamer=""
    running_version=""
fi
latest_version="$(echo "${debverlist}" | sed -n 1p)"
previous_version="$(echo "${debverlist}" | sed -n 2p)"

debkernels="$(echo "${latest_version}
${installed_version}
${running_version}" | sort -u | sed -e '/^$/ d')"
kernels="$( (echo "$1
${unamer}"; for deb in ${debkernels}; do echo "${list}" | awk "\$2 == \"${deb}\" { print \$1; }"; done; ) \
   | sed -e 's#\([\.\+]\)#\\\1#g' -e '/^$/ d' | sort -u|tr '\n' '|' | sed -e 's/|$//')"


echo "
List of installed kernel packages:
$list

# Running kernel: ${running_version:-ignored} (${unamer:-ignored})
# Last kernel: ${latest_version}
# Previous kernel: ${previous_version}
# Kernel versions list to keep:
${debkernels}

# Kernel packages (version part) to protect:
${kernels}
"

echo "BEFORE"
dpkg -l | grep linux-image

dpkg --get-selections | tr '\t' ' ' | cut -d" " -f1 | grep '^linux-image-[234]' | grep -v -E "(${kernels})" | xargs --no-run-if-empty ${APT} -o Dir::State::Lists="${listupgrade_state_dir}" -y purge

echo "
AFTER"
dpkg -l | grep linux-image
echo ""