Automating tedious kernel hacking related tasks.

kbuild-auto.sh

#!/bin/bash
#
# Copyright (C) 2016 Davidlohr Bueso.
#
# Download and build/install one or more flavors of the Linux kernel.
# Do what you please with this, but you better be root if you expect
# it to do anything useful. Also, probably very SUSE specific, this
# is my only working env.
#
# Usage:
#  kbuild-auto.sh  --config   <config-file>
#                 [--kernels  <master,v4.5,v4.5-rc1,...>]
#                 [--repo     <linux|tip|rcu|next|...>]
#                 [--force]   (removes any exising repository directory
#                              before cloning)
#                 [--cleanup] (removes cloned working directory once done)
#
#  notes:
#        o defaults will always be master branch on Linus' tree.
#        o the script does everything inside working directory where called.
#  examples:
#     ./kbuid-auto.sh --config /boot/config-4.5.0-rc5
#     ./kbuid-auto.sh --repo rcu --config /boot/config-4.5.0-rc5
#     ./kbuid-auto.sh --config /boot/config-4.5.0-rc5 --kernels v4.4,v4.5 --force
#
# TODO (wishlist):
#  o Change (grub) bootloader default.
#  o When available, use bkp protocol if default git:// fails.
#  o --repo-url <url> option, for non-tagged repositories.
#

KERNEL_DOTCONFIG="" # non-optional arg
GIT_REPO_ALIAS="linux"
KERNEL_STR="master"
GIT_REPO_FORCE=0 # do not overwrite an existing repo
GIT_REPO_CLEANUP=0 # cleanup after ourselves
NUMCPUS=$(grep -c '^processor' /proc/cpuinfo)
MAKE="make -j$((NUMCPUS*2))"

# Linus' and other common used trees for kernel development.
declare -A GIT_REPO_ARR
GIT_REPO_ARR["linux"]=git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
GIT_REPO_ARR["tip"]=git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
GIT_REPO_ARR["next"]=git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
GIT_REPO_ARR["rcu"]=git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
GIT_REPO_ARR["net"]=git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git
GIT_REPO_ARR["block"]=git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
# -- akpm
GIT_REPO_ARR["mmotm"]=git://git.cmpxchg.org/linux-mmotm.git
GIT_REPO_ARR["mmots"]=git://git.cmpxchg.org/linux-mmots.git

while [ "$1" != "" ]; do
    case "$1" in
	--config)
	    KERNEL_DOTCONFIG=$2
	    shift 2
	    ;;
	--kernels)
	    KERNEL_STR=$2
	    shift 2
	    ;;
	--repo)
	    GIT_REPO_ALIAS=$2
	    shift 2
	    ;;
    	--cleanup)
	    GIT_REPO_CLEANUP="yes"
	    shift 1
	    ;;
	--force)
	    GIT_REPO_FORCE="yes"
	    shift 1
	    ;;
	*)
	    echo Unrecognised option: $1
	    shift
    esac
done

#
# Input sanitation
#
if [ ! -f $KERNEL_DOTCONFIG ] || [ "$KERNEL_DOTCONFIG" = "" ]; then
    echo "$0: Must pass a valid base configuration file (--config)"
    exit 1
fi

# zypper in -y git-core gcc openssl-devel
GIT_CLONE_REPO=${GIT_REPO_ARR[$GIT_REPO_ALIAS]}

if [ "$GIT_CLONE_REPO" = "" ]; then
    echo "$0: '$GIT_REPO_ALIAS' is not a valid repository alias (--repo)"
    echo "$0: Available repositories are:  ${!GIT_REPO_ARR[@]}"
    exit 1
fi

if [ "$GIT_REPO_FORCE" = "yes" ]; then
    echo "$0: Deleting any previous '$GIT_REPO_ALIAS' directory"
    rm -rf $GIT_REPO_ALIAS # do not bother checking if it exists
fi

git clone $GIT_CLONE_REPO $GIT_REPO_ALIAS
cp $KERNEL_DOTCONFIG $GIT_REPO_ALIAS/.config && cd $GIT_REPO_ALIAS

#
# Lets do it!
#
IFS=',' read -a KERNEL_ARR <<< "$KERNEL_STR"
for KERNEL in ${KERNEL_ARR[@]}
do
#    echo "Checking out and building '${KERNEL}'"
    git checkout $KERNEL && make olddefconfig
			  # ^^ can return (ignorable) symbol warnings.
    $MAKE && $MAKE modules && $MAKE modules_install && $MAKE install
done

if [ "$GIT_REPO_CLEANUP" = "yes" ]; then
    cd .. && rm -rf $GIT_REPO_ALIAS
fi