#!/usr/bin/env bash

set -vx

# Author: Bhaskar Chowdhury <unixbhaskar@gmail.com>

# LICENSE: GPL-2

# Check out: https://www.kernel.org/doc/html/latest/kbuild/index.html

# For kernel download helper script: https://git.kernel.org/pub/scm/linux/kernel/git/mricon/korg-helpers.git/tree/get-verified-tarball

get_make=$(command -v make)

get_elapsed_time="/usr/bin/time -f"

untar_it="tar -xJvf"

existing_config_file="/boot/config-$(uname -r)"

build_dir=$HOME/latest_kernel_build

get_it=$(command -v secure_kernel_tarball)

EFIMENUENTRY="/boot/efi/loader/entries"

EFIBOOTDIR="/boot/efi/EFI"

NOTIFY=$(command -v notify-send)

LOCAL_BIN="/usr/local/bin"

dracut=$(command -v dracut)

clang="CC=clang"

make_llvm="LLVM=1"

llvm_assm="LLVM_IAS=1"

clear

cat << "EOF"

_ __ _

| |/ /___ _ __ _ __ ___| |

| ' // _ \ '__| '_ \ / _ \ |

| . \ __/ | | | | | __/ |

|_|\_\___|_| |_| |_|\___|_|_ _ _ _

/ ___|___ _ __ ___ _ __ (_) | __ _| |_(_) ___ _ __

| | / _ \| '_ ` _ \| '_ \| | |/ _` | __| |/ _ \| '_ \

| |__| (_) | | | | | | |_) | | | (_| | |_| | (_) | | | |

\____\___/|_| |_| |_| .__/|_|_|\__,_|\__|_|\___/|_| |_|

|_|

EOF

if [[ ! -d $build_dir ]];then

mkdir -p $build_dir

fi

cd $build_dir

slackware_kernel_build() {

#Download the kernel

which_kernel

eval ${get_it} ${kernel}

#Untar it

$untar_it linux-$kernel.tar.xz

#Get into the kernel direcory

cd linux-$kernel

#Check for required tools to build kernel

scripts/ver_linux

#Copying the existing system running kernel config

cp $existing_config_file .config

# Take away the DEBUG options for faster compile

scripts/config --disable DEBUG_KERNEL

grep DEBUG_KERNEL .config

#Similar vein like above, for faster compile time

scripts/config --disable DEBUG_INFO

grep DEBUG_INFO .config

#Make old kernel config set as well

$get_make olddefconfig

printf "Then make it ...\n\n"

which_compiler

#$get_elapsed_time "\t\n\n Elapsed time: %E\n\n" $get_make V=1 ARCH=x86_64 -j$(getconf _NPROCESSORS_ONLN) LOCALVERSION=-$(hostname)

$NOTIFY --urgency=critical 'Kernel compilation done'

if [[ $? == 0 ]];then

printf "Done\n\n"

else

printf "Error encountered\n\n"

fi

$NOTIFY --urgency=critical 'Modules install done'

printf "\n\n Copying the build kernel to boot directory\n\n"

cp arch/x86/boot/bzImage /boot/vmlinuz-$kernel-$(hostname)

$NOTIFY --urgency=critical 'Kernel install to local boot dir'

printf " Cross check the item ...\n\n"

ls -al /boot/vmlinuz-*

printf "\n\n Copy the System.map file to /boot dir\n\n"

cp System.map /boot/System.map-$kernel-$(hostname)

printf "Copying the .config file to /boot dir \n\n"

cp .config /boot/config-$kernel-$(hostname)

printf "Make sure we are in right directory ..\n\n"

cd /boot

pwd

printf "Lets relink System.map,config,huge,generic and normal against the new kernel!... \n\n"

unlink System.map

ln -s Systeme.map-$kernel-$(hostname) System.map

unlink config

ln -s config-$kernel-$(hostname) config

unlink vmlinuz

ln -s vmlinuz-$kernel-$(hostname) vmlinuz

unlink vmlinuz-huge

ln -s vmlinuz-$kernel-$(hostname) vmlinuz-huge

unlink vmlinuz-generic

ln -s vmlinuz-$kernel-$(hostname) vmlinuz-generic

find . -maxdepth 1 -type l -ls

printf "Done and looks good! \n\n"

printf "Copying the image to EFI directory ....\n\n"

cp -v /boot/vmlinuz-$kernel-$(hostname) $EFIBOOTDIR/slackware/

ls -al /boot/efi/EFI/slackware/*

$NOTIFY --urgency=critical 'Copied kernel to UEFI boot dir'

printf "\n\n Fixing the menu entry of the loader....\n\n\n"

>$EFIMENUENTRY/Slackware.conf

echo "title Slackware" > $EFIMENUENTRY/Slackware.conf

echo "linux /EFI/slackware/vmlinuz-$kernel-$(hostname)" >> $EFIMENUENTRY/Slackware.conf

echo "options root=PARTUUID=d3fe6218-506b-4ed1-ac14-97adb053baff rw" >> $EFIMENUENTRY/Slackware.conf

printf "Let see the entry to confirmation...\n\n\n"

cat $EFIMENUENTRY/Slackware.conf

$NOTIFY --urgency=critical 'Modified boot entry with latest kernel'

printf "\n\n Fix the UEFI boot shell script... ..\n\n\n"

echo "\EFI\slackware\vmlinuz-$kernel-$(hostname) root=PARTUUID=d3fe6218-506b-4ed1-ac14-97adb053baff rw" > /boot/efi/EFI/slackware.nsh

cat $EFIBOOTDIR/slackware.nsh

printf " Cleaning up the build directory .....\n\n"

rm -rf $build_dir

$NOTIFY --urgency=critical 'Kernel Update finished'

}

slackware_kernel_build

which_kernel() {

printf "\n\n Which kernel would be your base? Stable or Mainline or Longterm? [S/M/L]: %s"

read response

if [[ $response == "S" ]];then

#Get the stable kernel from kernel.org

kernel=$(curl -s https://www.kernel.org/ | grep -A1 'stable:' | grep -oP '(?<=strong>).*(?=</strong.*)' | grep 5.17)

elif [[ $response == "M" ]];then

#Get the mainline kernel from kernel.org

kernel=$(curl -s https://www.kernel.org/ | grep -A1 'mainline:' | grep -oP '(?<=strong>).*(?=</strong.*)')

elif [[ $response == "L" ]];then

#Get the longterm kernel from kernel.org

kernel=$(curl -s https://www.kernel.org/ | grep -A1 'longterm:' | grep -oP '(?<=strong>).*(?=</strong.*)')

fi

}

#This is assuming that you have already installed "clang" and "llvm" in the system

which_compiler() {

printf "\n\t Which compiler do you want to use for build ,CLANG or GCC? [C/G] : %s"

read compiler_chosen

if [[ $compiler_chosen == "G" ]];then

gcc_compile

elif [[ $compiler_chosen == "C" ]];then

clang_llvm_compile

else

printf "\n\n You have to choose a compiler to build.\n"

exit 1

fi

}

gcc_compile() {

printf "\n You have chosen to use GCC as the compiler to build.\n\n"

$get_make ARCH=x86_64 olddefconfig

$get_elapsed_time "\t\n\n Elapsed Time : %E \n\n" $get_make ARCH=x86_64 V=1 -j$(getconf _NPROCESSORS_ONLN) LOCALVERSION=-$(hostname)

$get_make cleandocs

$get_make modules_install

}

clang_llvm_compile() {

printf "\n\t You have chosen to use CLANG as the compiler to build.\n\n"

$get_make $clang $host_clang_cc $llvm_make $llvm_assm ARCH=x86_64 olddefconfig

$get_elapsed_time "\n\t Elapsed Time: %E \n\n" $get_make $clang $host_clang_cc $llvm_make $llvm_assm ARCH=x86_64 V=1 -j$(getconf _NPROCESSORS_ONLN)

$get_make cleandocs

$get_make $clang $llvm_make $llvm_assm modules_install

}