#! /bin/sh
  # SPDX-License-Identifier: GPL-2.0
  # Script to apply kernel patches.
  #   usage: patch-kernel [ sourcedir [ patchdir [ stopversion ] [ -acxx ] ] ]
  #     The source directory defaults to /usr/src/linux, and the patch
  #     directory defaults to the current directory.
  # e.g.
  #   scripts/patch-kernel . ..
  #      Update the kernel tree in the current directory using patches in the
  #      directory above to the latest Linus kernel
  #   scripts/patch-kernel . .. -ac
  #      Get the latest Linux kernel and patch it with the latest ac patch
  #   scripts/patch-kernel . .. 2.4.9
  #      Gets standard kernel 2.4.9
  #   scripts/patch-kernel . .. 2.4.9 -ac
  #      Gets 2.4.9 with latest ac patches
  #   scripts/patch-kernel . .. 2.4.9 -ac11
  #      Gets 2.4.9 with ac patch ac11
  #   Note: It uses the patches relative to the Linus kernels, not the
  #   ac to ac relative patches
  #
  # It determines the current kernel version from the top-level Makefile.
  # It then looks for patches for the next sublevel in the patch directory.
  # This is applied using "patch -p1 -s" from within the kernel directory.
  # A check is then made for "*.rej" files to see if the patch was
  # successful.  If it is, then all of the "*.orig" files are removed.
  #
  #       Nick Holloway <Nick.Holloway@alfie.demon.co.uk>, 2nd January 1995.
  #
  # Added support for handling multiple types of compression. What includes
  # gzip, bzip, bzip2, zip, compress, and plaintext.
  #
  #       Adam Sulmicki <adam@cfar.umd.edu>, 1st January 1997.
  #
  # Added ability to stop at a given version number
  # Put the full version number (i.e. 2.3.31) as the last parameter
  #       Dave Gilbert <linux@treblig.org>, 11th December 1999.
  
  # Fixed previous patch so that if we are already at the correct version
  # not to patch up.
  #
  # Added -ac option, use -ac or -ac9 (say) to stop at a particular version
  #       Dave Gilbert <linux@treblig.org>, 29th September 2001.
  #
  # Add support for (use of) EXTRAVERSION (to support 2.6.8.x, e.g.);
  # update usage message;
  # fix some whitespace damage;
  # be smarter about stopping when current version is larger than requested;
  #	Randy Dunlap <rdunlap@xenotime.net>, 2004-AUG-18.
  #
  # Add better support for (non-incremental) 2.6.x.y patches;
  # If an ending version number if not specified, the script automatically
  # increments the SUBLEVEL (x in 2.6.x.y) until no more patch files are found;
  # however, EXTRAVERSION (y in 2.6.x.y) is never automatically incremented
  # but must be specified fully.
  #
  # patch-kernel does not normally support reverse patching, but does so when
  # applying EXTRAVERSION (x.y) patches, so that moving from 2.6.11.y to 2.6.11.z
  # is easy and handled by the script (reverse 2.6.11.y and apply 2.6.11.z).
  #	Randy Dunlap <rdunlap@xenotime.net>, 2005-APR-08.
  
  PNAME=patch-kernel
  
  # Set directories from arguments, or use defaults.
  sourcedir=${1-/usr/src/linux}
  patchdir=${2-.}
  stopvers=${3-default}
  
  if [ "$1" = -h -o "$1" = --help -o ! -r "$sourcedir/Makefile" ]; then
  cat << USAGE
  usage: $PNAME [-h] [ sourcedir [ patchdir [ stopversion ] [ -acxx ] ] ]
    source directory defaults to /usr/src/linux,
    patch directory defaults to the current directory,
    stopversion defaults to <all in patchdir>.
  USAGE
  exit 1
  fi
  
  # See if we have any -ac options
  for PARM in $*
  do
    case $PARM in
  	  -ac*)
  		  gotac=$PARM;
  
  	esac;
  done
  
  # ---------------------------------------------------------------------------
  # arg1 is filename
  noFile () {
  	echo "cannot find patch file: ${patch}"
  	exit 1
  }
  
  # ---------------------------------------------------------------------------
  backwards () {
  	echo "$PNAME does not support reverse patching"
  	exit 1
  }
  
  # ---------------------------------------------------------------------------
  # Find a file, first parameter is basename of file
  # it tries many compression mechanisms and sets variables to say how to get it
  findFile () {
    filebase=$1;
  
    if [ -r ${filebase}.gz ]; then
  		ext=".gz"
  		name="gzip"
  		uncomp="gunzip -dc"
    elif [ -r ${filebase}.bz  ]; then
  		ext=".bz"
  		name="bzip"
  		uncomp="bunzip -dc"
    elif [ -r ${filebase}.bz2 ]; then
  		ext=".bz2"
  		name="bzip2"
  		uncomp="bunzip2 -dc"
    elif [ -r ${filebase}.xz ]; then
                  ext=".xz"
                  name="xz"
                  uncomp="xz -dc"
    elif [ -r ${filebase}.zip ]; then
  		ext=".zip"
  		name="zip"
  		uncomp="unzip -d"
    elif [ -r ${filebase}.Z ]; then
  		ext=".Z"
  		name="uncompress"
  		uncomp="uncompress -c"
    elif [ -r ${filebase} ]; then
  		ext=""
  		name="plaintext"
  		uncomp="cat"
    else
  	return 1;
    fi
  
    return 0;
  }
  
  # ---------------------------------------------------------------------------
  # Apply a patch and check it goes in cleanly
  # First param is patch name (e.g. patch-2.4.9-ac5) - without path or extension
  
  applyPatch () {
    echo -n "Applying $1 (${name})... "
    if $uncomp ${patchdir}/$1${ext} | patch -p1 -s -N -E -d $sourcedir
    then
      echo "done."
    else
      echo "failed.  Clean up yourself."
      return 1;
    fi
    if [ "`find $sourcedir/ '(' -name '*.rej' -o -name '.*.rej' ')' -print`" ]
    then
      echo "Aborting.  Reject files found."
      return 1;
    fi
    # Remove backup files
    find $sourcedir/ '(' -name '*.orig' -o -name '.*.orig' ')' -exec rm -f {} \;
  
    return 0;
  }
  
  # ---------------------------------------------------------------------------
  # arg1 is patch filename
  reversePatch () {
  	echo -n "Reversing $1 (${name}) ... "
  	if $uncomp ${patchdir}/"$1"${ext} | patch -p1 -Rs -N -E -d $sourcedir
  	then
  		echo "done."
  	else
  		echo "failed.  Clean it up."
  		exit 1
  	fi
  	if [ "`find $sourcedir/ '(' -name '*.rej' -o -name '.*.rej' ')' -print`" ]
  	then
  		echo "Aborting.  Reject files found."
  		return 1
  	fi
  	# Remove backup files
  	find $sourcedir/ '(' -name '*.orig' -o -name '.*.orig' ')' -exec rm -f {} \;
  
  	return 0
  }
  
  # set current VERSION, PATCHLEVEL, SUBLEVEL, EXTRAVERSION
  # force $TMPFILEs below to be in local directory: a slash character prevents
  # the dot command from using the search path.
  TMPFILE=`mktemp ./.tmpver.XXXXXX` || { echo "cannot make temp file" ; exit 1; }
  grep -E "^(VERSION|PATCHLEVEL|SUBLEVEL|EXTRAVERSION)" $sourcedir/Makefile > $TMPFILE
  tr -d [:blank:] < $TMPFILE > $TMPFILE.1
  . $TMPFILE.1
  rm -f $TMPFILE*
  if [ -z "$VERSION" -o -z "$PATCHLEVEL" -o -z "$SUBLEVEL" ]
  then
      echo "unable to determine current kernel version" >&2
      exit 1
  fi
  
  NAME=`grep ^NAME $sourcedir/Makefile`
  NAME=${NAME##*=}
  
  echo "Current kernel version is $VERSION.$PATCHLEVEL.$SUBLEVEL${EXTRAVERSION} ($NAME)"
  
  # strip EXTRAVERSION to just a number (drop leading '.' and trailing additions)
  EXTRAVER=
  if [ x$EXTRAVERSION != "x" ]
  then
  	EXTRAVER=${EXTRAVERSION#.}
  	EXTRAVER=${EXTRAVER%%[[:punct:]]*}
  	#echo "$PNAME: changing EXTRAVERSION from $EXTRAVERSION to $EXTRAVER"
  fi
  
  #echo "stopvers=$stopvers"
  if [ $stopvers != "default" ]; then
  	STOPSUBLEVEL=`echo $stopvers | cut -d. -f3`
  	STOPEXTRA=`echo $stopvers | cut -d. -f4`
  	STOPFULLVERSION=${stopvers%%.$STOPEXTRA}
  	#echo "#___STOPSUBLEVEL=/$STOPSUBLEVEL/, STOPEXTRA=/$STOPEXTRA/"
  else
  	STOPSUBLEVEL=9999
  	STOPEXTRA=9999
  fi
  
  # This all assumes a 2.6.x[.y] kernel tree.
  # Don't allow backwards/reverse patching.
  if [ $STOPSUBLEVEL -lt $SUBLEVEL ]; then
  	backwards
  fi
  
  if [ x$EXTRAVER != "x" ]; then
  	CURRENTFULLVERSION="$VERSION.$PATCHLEVEL.$SUBLEVEL.$EXTRAVER"
  else
  	CURRENTFULLVERSION="$VERSION.$PATCHLEVEL.$SUBLEVEL"
  fi
  
  if [ x$EXTRAVER != "x" ]; then
  	echo "backing up to: $VERSION.$PATCHLEVEL.$SUBLEVEL"
  	patch="patch-${CURRENTFULLVERSION}"
  	findFile $patchdir/${patch} || noFile ${patch}
  	reversePatch ${patch} || exit 1
  fi
  
  # now current is 2.6.x, with no EXTRA applied,
  # so update to target SUBLEVEL (2.6.SUBLEVEL)
  # and then to target EXTRAVER (2.6.SUB.EXTRAVER) if requested.
  # If not ending sublevel is specified, it is incremented until
  # no further sublevels are found.
  
  if [ $STOPSUBLEVEL -gt $SUBLEVEL ]; then
  while :				# incrementing SUBLEVEL (s in v.p.s)
  do
      CURRENTFULLVERSION="$VERSION.$PATCHLEVEL.$SUBLEVEL"
      EXTRAVER=
      if [ x$STOPFULLVERSION = x$CURRENTFULLVERSION ]; then
          echo "Stopping at $CURRENTFULLVERSION base as requested."
          break
      fi
  
      SUBLEVEL=$(($SUBLEVEL + 1))
      FULLVERSION="$VERSION.$PATCHLEVEL.$SUBLEVEL"
      #echo "#___ trying $FULLVERSION ___"
  
      if [ $(($SUBLEVEL)) -gt $(($STOPSUBLEVEL)) ]; then
  	echo "Stopping since sublevel ($SUBLEVEL) is beyond stop-sublevel ($STOPSUBLEVEL)"
  	exit 1
      fi
  
      patch=patch-$FULLVERSION
      # See if the file exists and find extension
      findFile $patchdir/${patch} || noFile ${patch}
  
      # Apply the patch and check all is OK
      applyPatch $patch || break
  done
  #echo "#___sublevel all done"
  fi
  
  # There is no incremental searching for extraversion...
  if [ "$STOPEXTRA" != "" ]; then
  while :				# just to allow break
  do
  # apply STOPEXTRA directly (not incrementally) (x in v.p.s.x)
  	FULLVERSION="$VERSION.$PATCHLEVEL.$SUBLEVEL.$STOPEXTRA"
  	#echo "#... trying $FULLVERSION ..."
  	patch=patch-$FULLVERSION
  
  	# See if the file exists and find extension
  	findFile $patchdir/${patch} || noFile ${patch}
  
  	# Apply the patch and check all is OK
  	applyPatch $patch || break
  	#echo "#___extraver all done"
  	break
  done
  fi
  
  if [ x$gotac != x ]; then
    # Out great user wants the -ac patches
  	# They could have done -ac (get latest) or -acxx where xx=version they want
  	if [ $gotac = "-ac" ]; then
  	  # They want the latest version
  		HIGHESTPATCH=0
  		for PATCHNAMES in $patchdir/patch-${CURRENTFULLVERSION}-ac*\.*
  		do
  			ACVALUE=`echo $PATCHNAMES | sed -e 's/^.*patch-[0-9.]*-ac\([0-9]*\).*/\1/'`
  			# Check it is actually a recognised patch type
  			findFile $patchdir/patch-${CURRENTFULLVERSION}-ac${ACVALUE} || break
  
  		  if [ $ACVALUE -gt $HIGHESTPATCH ]; then
  			  HIGHESTPATCH=$ACVALUE
  		  fi
  		done
  
  		if [ $HIGHESTPATCH -ne 0 ]; then
  			findFile $patchdir/patch-${CURRENTFULLVERSION}-ac${HIGHESTPATCH} || break
  			applyPatch patch-${CURRENTFULLVERSION}-ac${HIGHESTPATCH}
  		else
  		  echo "No -ac patches found"
  		fi
  	else
  	  # They want an exact version
  		findFile $patchdir/patch-${CURRENTFULLVERSION}${gotac} || {
  		  echo "Sorry, I couldn't find the $gotac patch for $CURRENTFULLVERSION.  Hohum."
  			exit 1
  		}
  		applyPatch patch-${CURRENTFULLVERSION}${gotac}
  	fi
  fi