#!/bin/sh -e
# written by Thomas Penteker <tek@serverop.de> Mon Sep 18 00:32:57 CEST 2006
# version 28686736
# this script possibly updates your current kernel (no 'installation' is done)
# no responsibility is taken
# depends on: wget, (g)unzip 

# main script routine
main() {
 
configfile=$(get_config)

if [ "$configfile" = "none" ]; then
  echo Options
  echo " CONFIG=y"
  echo " CONFIG_PROC=y"
  echo "have to be set in your kernel config or provide your .config"
  echo "in the same directory as this script."
  exit 1
fi

remote_version=${remote_version:-$(remote_v)}

#if [ $force = 1 ];then
#  local_version=$remote_version
#else
  local_version=$(local_v)
#fi

if [ "$remote_version" != "$local_version" ]; then
  echo "new kernel $remote_version" 
  if [ "$test" = 1 ]; then
    exit 0
  else
    echo "Fetching ${remote_version} from kernel.org"
  fi
  fetch_kernel
  echo " ..done"

  echo "Unpacking it to $PWD"
  tar xjf linux-${remote_version}.tar.bz2
  echo " ..done"
  cd linux-${remote_version}
  if [ $force=1 ];then
    make clean
  fi
  if [ "$configfile" = ".config" ]; then
    cp ../.config .
  else
    zcat /proc/config > .config
  fi

  #dopatch
  
  make oldconfig
  echo "+ make -j$(($(grep -c MHz /proc/cpuinfo)-0))"
  make -j$(($(grep -c MHz /proc/cpuinfo)-1))

  if grep -vq "# CONFIG_MODULES" .config; then
    echo "+ make modules"
    make modules 
  fi

  echo "copying kernel to ../bzImage"
  cp arch/$(arch)/boot/bzImage ../
  cd ..
  #if [ $dell = 1 ]; then
  #  rm -rf linux-${remote_version}
  #elif [ $delall = 1 ]; then
  #  rm -rf linux-${remote_version} linux-${remote_version}.tar.bz2
  #fi

  echo " ..done"

else
  echo "Kernel up-to-date.(local:$local_version remote:$remote_version)"
fi

}

getoptions() {
  dell=1
  delall=1
while getopts Ddhfr:tp:t option; do
  case $option in
    "t") export test=1 ;;
    "D") export delall=1 ;;
    "d") export dell=1 ;;
    "f") export force=1 ;;
    "r") export remote_version="$OPTARG" ;;
    "p") echo p $OPTARG ;;
    #"p") p1[$((${#p1[@]}+1))]=$OPTARG ;; # collect patches
    [?]|"h") echo "usage: " $(basename $0) "[OPTION]
        where [OPTION] may be a combination of:
        [-d] remove linux-x.y.z directory after operation
        [-D] remove linux-x.y.z directory and archive after opertaion
        [-t] test mode, check only for new kernel version
        [-f] force compilation of kernel
        [-r remote-version] set new kernel version to remote-version
        [-p diff1 -p diff2 ...] apply patches (i.e. patch -p1 -i diff1)";exit ;;
  esac
done
}

local_v() {
  echo $(uname -r | cut -d '-' -f 1 | sed -e 's/\([0-9]\+\)\([\.0-9]\+\)\(.*\)/\1\2/g')
}

remote_v() {
  echo $(wget -qO - kernel.org/kdist/finger_banner | sort -n -r | \
         awk -F: '/stable/ { gsub(" ","",$2); print $2; exit }')
}

#dopatch() {
#  if [ ${#p1[@]} -gt 0 ]; then
#    for i in ${p1[@]};do
#      echo "Applying patch $i"
#      patch -s -p1 -i ../"$i";
#    done
#  fi
#}

get_config() {

if [ -f "${PWD}"/.config ]; then
  echo .config
elif [ -f /proc/config.gz ]; then
  echo /proc/config.gz
else
  echo none
fi

}

arch() {
case $(uname -m) in
  i386|i486|i568|i686)  arch=x86 ;;
  x86_64*)    arch=x86 ;;
  amd64*)     arch=x86 ;;
  alpha*)     arch=alpha ;;
  ia64*)      arch=ia64 ;;
  powerpc*)   arch=powerpc ;;
  ppc*)       arch=ppc ;;
  sparc64*)   arch=sparc64 ;;
  sparc*)     arch=sparc ;;
  mips*)      arch=mips ;;
  *)          arch=x86 ;;
esac

echo $arch
}

fetch_kernel() {
  wget -c --timestamping \
      http://kernel.org/pub/linux/kernel/v3.0/linux-${remote_version}.tar.bz2
}


getoptions $@
main