#!/bin/bash

if [ `whoami` != "root" ]; then
    echo "$0 must be run as root!"
    exit 1
fi

if [ $# -lt 3 ]; then
    echo "usage: $0 <major minor micro [revision], e.g. 2 6 21 r4>"
    exit 1
fi

MAJOR=$1
MINOR=$2
MICRO=$3
if [ $# -gt 3 ]; then
    REVISION=$4
fi

FULL_VERSION="${MAJOR}.${MINOR}.${MICRO}"
if [[ "${REVISION}" != "" ]]; then
	FULL_VERSION="${FULL_VERSION}-${REVISION}"
fi

ARCH=`uname -m`
if [ "$ARCH" = "i686" ]; then
    ARCH="x86"
fi

KERNEL_FLAVOR=""
KERNEL_EBUILD="vanilla-sources"
if [[ "$(grep gentoo-sources /var/lib/portage/world)" != "" ]]; then
	KERNEL_FLAVOR="-gentoo"
	KERNEL_EBUILD="gentoo-sources"
fi

LOGFILE=/tmp/removeKernel-$$.log

# unmerge the kernel
cd /usr/src
KERNEL_DIR="linux-${MAJOR}.${MINOR}.${MICRO}${KERNEL_FLAVOR}"
if [[ "${REVISION}" != "" ]]; then
    KERNEL_DIR="${KERNEL_DIR}-${REVISION}"
fi
if [[ -d $KERNEL_DIR ]]; then
	KERNEL_NAME="${KERNEL_EBUILD}-${FULL_VERSION}"

    echo "unmerge kernel $KERNEL_NAME" >> $LOGFILE 2>&1
    emerge --unmerge $KERNEL_NAME >> $LOGFILE 2>&1

    echo "remove $KERNEL_DIR" >> $LOGFILE 2>&1
    rm -r  $KERNEL_DIR >> $LOGFILE 2>&1
fi

# remove modules
cd /lib/modules
LIB_DIR="${FULL_VERSION}${KERNEL_FLAVOR}-${ARCH}"
if [[ -d ${LIB_DIR} ]]; then
    echo "remove modules from $(pwd)/${LIB_DIR}" >> $LOGFILE 2>&1
    rm -r ${LIB_DIR} >> $LOGFILE 2>&1
fi

# remove the kernel and stuff, check if /boot is mounted first
MOUNTED=`mount | grep /boot`
if [ "$MOUNTED" = "" ]; then
    echo "mount /boot" >> $LOGFILE 2>&1
    mount /boot >> $LOGFILE 2>&1
fi

cd /boot

SYSTEM_MAP="System.map-${FULL_VERSION}${KERNEL_FLAVOR}-${ARCH}"
if [[ -f ${SYSTEM_MAP} ]]; then
	rm ${SYSTEM_MAP} >> $LOGFILE 2>&1
fi
if [[ -f ${SYSTEM_MAP}.old ]]; then
	rm ${SYSTEM_MAP}.old >> $LOGFILE 2>&1
fi

INITRAMFS="initramfs-${FULL_VERSION}${KERNEL_FLAVOR}-${ARCH}.img"
if [[ -f ${INITRAMFS} ]]; then
	rm ${INITRAMFS} >> $LOGFILE 2>&1
fi
if [[ -f ${INITRAMFS}.old ]]; then
	rm ${INITRAMFS}.old >> $LOGFILE 2>&1
fi

KERNEL="vmlinuz-${FULL_VERSION}${KERNEL_FLAVOR}-${ARCH}"
if [[ -f $KERNEL ]]; then
	rm $KERNEL >> $LOGFILE 2>&1
fi
if [[ -f $KERNEL.old ]]; then
	rm $KERNEL.old >> $LOGFILE 2>&1
fi

cd /var/tmp/genkernel
INITRAMFS="initramfs-${ARCH}-${FULL_VERSION}${KERNEL_FLAVOR}-${ARCH}"
if [[ -f ${INITRAMFS} ]]; then
    rm ${INITRAMFS} >> $LOGFILE 2>&1
fi

# if we got until here, just remove the logfile again
rm $LOGFILE