#!/bin/bash

SILENT=false
MRPROPER=false
NICE_CMD="nice -n 19 ionice -c2"
CONFIG_FILE=/proc/config.gz
GENKERNEL_ARGS=""
USE_GENKERNEL=true

[ -f /etc/gentoo-upgrade.conf ] && source /etc/gentoo-upgrade.conf

# available parameters
eval set -- "`getopt -o hsc: --long help,silent,mrproper,config: -- \"$@\"`"

while true ; do
    case "$1" in
        -h|--help)
            echo "Usage: kernel-rebuild.sh [keys]..."
            echo "Keys:"
            echo -e "-h, --help\t\tShow this help and exit."
            echo -e "-s, --silent\t\tMake with silentoldconfig."
            echo -e "--mrproper\t\tClean kernel sources before rebuild."
            echo -e "-c, --config [CONFIG]\tPath to custom kernel config."
            echo
            echo -e "This program works on any GNU/Linux with GNU Baurne's shell"
            echo -e "Report bugs to <mecareful@gmail.com>"
            exit 0
            ;;
        -s|--silent) SILENT=true ; shift ;;
        --mrproper) MRPROPER=true ; shift ;;
        -c|--config) CONFIG_FILE=$2 ; shift 2 ;;
        --) shift ; break ;;
        *) echo "Internal error!" ; exit -1 ;;
    esac
done

[ "$SILENT" != "true" ] && GENKERNEL_ARGS="$GENKERNEL_ARGS --menuconfig"
[ "$MRPROPER" == "true" ] && GENKERNEL_ARGS="$GENKERNEL_ARGS --mrproper"
which genkernel &>/dev/null || USE_GENKERNEL=false

# remounting file systems ro->rw
for fs in $RW_REMOUNT; do
    if [[ "$fs" =~ ^/+usr/*$ || "$fs" =~ ^/+boot/*$ ]]; then
        echo "remounting $fs -> rw"
        mount -o remount,rw $fs
        [ 0 -ne $? ] && echo "mount -o remount,rw $fs failed ;-( =======" && exit -1
    fi
done

cd /usr/src/linux
[ "$?" != "0" ] && echo /usr/src/linux doesn\'t exist && exit -1

if [ true == "$MRPROPER" ]; then
    make clean && make mrproper
    [ 0 -ne $? ] && echo "make clean && make mrproper failed ;-( =======" && exit -1
fi
echo CONFIG_FILE=$CONFIG_FILE
zcat $CONFIG_FILE >.config 2>/dev/null || cat $CONFIG_FILE >.config
[ "$?" != "0" ] && echo "$CONFIG_FILE doesn't exist or /usr mounted as read-only" && exit -1

make olddefconfig
[ "$?" != "0" ] && echo "======= make olddefconfig failed ;-( =======" && exit -1

# aufs3 patches
if [[ `qlist -IC sys-fs/aufs3 | wc -l` != 0 ]]; then
    make modules_prepare
    [ 0 -ne $? ] && echo "make modules_prepare failed ;-(" && exit -1
    emerge -1 sys-fs/aufs3
    [ 0 -ne $? ] && echo "emerge -1 sys-fs/aufs3 failed ;-(" && exit -1
fi

jobs=$((`getconf _NPROCESSORS_ONLN`+1))

if [ "$USE_GENKERNEL" == "true" ]; then
    MENUCONFIG_MODE=single_menu MENUCONFIG_COLOR=mono genkernel --makeopts=-j$jobs $GENKERNEL_ARGS all
    [ 0 -ne $? ] && echo "genkernel $GENKERNEL_ARGS all failed ;-( =======" && exit -1
else
    if [ true != "$SILENT" ]; then
        TERM=screen make MENUCONFIG_MODE=single_menu MENUCONFIG_COLOR=mono menuconfig
        [ "$?" != "0" ] && echo "======= make menuconfig failed ;-( =======" && exit -1
    fi

    # disable distcc for -march=native -mtune=native
    grep 'CONFIG_X86_MARCH_NATIVE=y' .config &>/dev/null
    if [[ "$?" == 0 ]]; then
        $NICE_CMD make -j$jobs
        [ 0 -ne $? ] && echo "Kernel build failed ;-(" && exit -1
    else
        # pump make -j$((jobs*3)) || make -j$jobs
        $NICE_CMD make -j$jobs
        [ 0 -ne $? ] && echo "Kernel build failed ;-(" && exit -1
    fi

    $NICE_CMD make install
    $NICE_CMD make modules_install

    REVISION=`cat /usr/src/linux/include/config/kernel.release`

    which dracut &>/dev/null && $NICE_CMD dracut --hostonly --force /boot/initramfs-$REVISION.img $REVISION
fi

# Updating Grub config
echo "Updating Grub menu"
if [ `which grub-mkconfig 2>/dev/null` ]; then
	[ -f /boot/grub/grub.cfg ] && grub-mkconfig -o /boot/grub/grub.cfg
	[ -f /boot/grub2/grub.cfg ] && grub-mkconfig -o /boot/grub2/grub.cfg
elif [ `which grub2-mkconfig 2>/dev/null` ]; then
	[ -f /boot/grub/grub.cfg ] && grub2-mkconfig -o /boot/grub/grub.cfg
	[ -f /boot/grub2/grub.cfg ] && grub2-mkconfig -o /boot/grub2/grub.cfg
else
	[ -f /boot/grub/grub.conf ] && \
	sed -i "s~\/boot\/vmlinuz-[0-9][^ ]*~\/boot\/vmlinuz-$REVISION~g;
	        s~\/boot\/kernel-genkernel-`uname -m`-[0-9][^ ]*~\/boot\/kernel-genkernel-`uname -m`-$REVISION~g;
	        s~\/boot\/initramfs-[0-9][^ ]*~\/boot\/initramfs-$REVISION.img~g" \
	        /boot/grub/grub.conf
fi

echo "--------- Rebuilding kernel modules ---------"
emerge -1v @module-rebuild
[ 0 -ne $? ] && echo "Upgrading kernel modules failed ;-(" && exit -1

cd $pwdtmp 

# remounting file systems rw->ro
for fs in $RO_REMOUNT; do
    if [[ "$fs" =~ ^/+usr/*$ || "$fs" =~ ^/+boot/*$ ]]; then
        echo "remounting $fs -> ro"
        mount -o remount,ro -force $fs
        [ 0 -ne $? ] && echo "mount -o remount,ro -force $fs failed ;-( =======" && exit -1
    fi
done

exit 0