anykernel3-rhode/tools/ak3-core.sh

### AnyKernel methods (DO NOT CHANGE)
## osm0sis @ xda-developers

OUTFD=$1;

# set up working directory variables
test "$home" || home=$PWD;
bootimg=$home/boot.img;
bin=$home/tools;
patch=$home/patch;
ramdisk=$home/ramdisk;
split_img=$home/split_img;

### output/testing functions:
# ui_print "<text>" [...]
ui_print() {
  until [ ! "$1" ]; do
    echo -e "ui_print $1\nui_print" > /proc/self/fd/$OUTFD;
    shift;
  done;
}

# abort ["<text>" [...]]
abort() {
  ui_print " " "$*";
  exit 1;
}

# contains <string> <substring>
contains() {
  test "${1#*$2}" != "$1";
}

# file_getprop <file> <property>
file_getprop() {
  grep "^$2=" "$1" | cut -d= -f2-;
}
###

### dump_boot functions:
# split_boot (dump and split image only)
split_boot() {
  local dumpfail;

  if [ ! -e "$(echo $block | cut -d\  -f1)" ]; then
    abort "Invalid partition. Aborting...";
  fi;
  if [ "$(echo $block | grep ' ')" ]; then
    block=$(echo $block | cut -d\  -f1);
    customdd=$(echo $block | cut -d\  -f2-);
  elif [ ! "$customdd" ]; then
    local customdd="bs=1048576";
  fi;
  if [ -f "$bin/nanddump" ]; then
    $bin/nanddump -f $bootimg $block;
  else
    dd if=$block of=$bootimg $customdd;
  fi;
  test $? != 0 && dumpfail=1;

  mkdir -p $split_img;
  cd $split_img;
  if [ -f "$bin/unpackelf" ] && $bin/unpackelf -i $bootimg -h -q 2>/dev/null; then
    if [ -f "$bin/elftool" ]; then
      mkdir elftool_out;
      $bin/elftool unpack -i $bootimg -o elftool_out;
    fi;
    $bin/unpackelf -i $bootimg;
    test $? != 0 && dumpfail=1;
    mv -f boot.img-zImage kernel.gz;
    mv -f boot.img-ramdisk.cpio.gz ramdisk.cpio.gz;
    mv -f boot.img-cmdline cmdline.txt;
    if [ -f boot.img-dt -a ! -f "$bin/elftool" ]; then
      case $(od -ta -An -N4 boot.img-dt | sed -e 's/ del//' -e 's/   //g') in
        QCDT|ELF) mv -f boot.img-dt dt;;
        *)
          gzip -c kernel.gz > kernel.gz-dtb;
          cat boot.img-dt >> kernel.gz-dtb;
          rm -f boot.img-dt kernel.gz;
        ;;
      esac;
    fi;
  elif [ -f "$bin/mboot" ]; then
    $bin/mboot -u -f $bootimg;
  elif [ -f "$bin/dumpimage" ]; then
    dd bs=$(($(printf '%d\n' 0x$(hexdump -n 4 -s 12 -e '16/1 "%02x""\n"' $bootimg)) + 64)) count=1 conv=notrunc if=$bootimg of=boot-trimmed.img;
    $bin/dumpimage -l boot-trimmed.img > header;
    grep "Name:" header | cut -c15- > boot.img-name;
    grep "Type:" header | cut -c15- | cut -d\  -f1 > boot.img-arch;
    grep "Type:" header | cut -c15- | cut -d\  -f2 > boot.img-os;
    grep "Type:" header | cut -c15- | cut -d\  -f3 | cut -d- -f1 > boot.img-type;
    grep "Type:" header | cut -d\( -f2 | cut -d\) -f1 | cut -d\  -f1 | cut -d- -f1 > boot.img-comp;
    grep "Address:" header | cut -c15- > boot.img-addr;
    grep "Point:" header | cut -c15- > boot.img-ep;
    $bin/dumpimage -p 0 -o kernel.gz boot-trimmed.img;
    test $? != 0 && dumpfail=1;
    case $(cat boot.img-type) in
      Multi) $bin/dumpimage -p 1 -o ramdisk.cpio.gz boot-trimmed.img;;
      RAMDisk) mv -f kernel.gz ramdisk.cpio.gz;;
    esac;
  elif [ -f "$bin/rkcrc" ]; then
    dd bs=4096 skip=8 iflag=skip_bytes conv=notrunc if=$bootimg of=ramdisk.cpio.gz;
  else
    $bin/magiskboot unpack -h $bootimg;
  fi;

  if [ $? != 0 -o "$dumpfail" ]; then
    abort "Dumping/splitting image failed. Aborting...";
  fi;
  cd $home;
}

# unpack_ramdisk (extract ramdisk only)
unpack_ramdisk() {
  local comp;

  cd $split_img;
  if [ -f ramdisk.cpio.gz ]; then
    if [ -f "$bin/mkmtkhdr" ]; then
      mv -f ramdisk.cpio.gz ramdisk.cpio.gz-mtk;
      dd bs=512 skip=1 conv=notrunc if=ramdisk.cpio.gz-mtk of=ramdisk.cpio.gz;
    fi;
    mv -f ramdisk.cpio.gz ramdisk.cpio;
  fi;

  comp=$($bin/magiskboot decompress ramdisk.cpio 2>&1 | head -n1 | cut -d[ -f2 | cut -d] -f1 | grep -v 'compressed');
  if [ "$comp" -a "$comp" != "raw" ]; then
    mv -f ramdisk.cpio ramdisk.cpio.$comp;
    $bin/magiskboot decompress ramdisk.cpio.$comp ramdisk.cpio;
    if [ $? != 0 ]; then
      echo "Attempting with busybox $comp..." >&2;
      $comp -dc ramdisk.cpio.$comp > ramdisk.cpio;
    fi;
  fi;

  mv -f $ramdisk $home/rdtmp;
  mkdir -p $ramdisk;
  chmod 755 $ramdisk;

  cd $ramdisk;
  EXTRACT_UNSAFE_SYMLINKS=1 cpio -d -F $split_img/ramdisk.cpio -i;
  if [ $? != 0 -o ! "$(ls)" ]; then
    abort "Unpacking ramdisk failed. Aborting...";
  fi;
  if [ "$(ls $home/rdtmp)" ]; then
    cp -af $home/rdtmp/* .;
  fi;
}
### dump_boot (dump and split image, then extract ramdisk)
dump_boot() {
  split_boot;
  unpack_ramdisk;
}
###

### write_boot functions:
# repack_ramdisk (repack ramdisk only)
repack_ramdisk() {
  local comp packfail mtktype;

  cd $home;
  case $ramdisk_compression in
    auto|"") comp=$(ls $split_img/ramdisk.cpio.* 2>/dev/null | grep -v 'mtk' | rev | cut -d. -f1 | rev);;
    none|cpio) comp="";;
    gz) comp=gzip;;
    lzo) comp=lzop;;
    bz2) comp=bzip2;;
    lz4-l) comp=lz4_legacy;;
    *) comp=$ramdisk_compression;;
  esac;

  if [ -f "$bin/mkbootfs" ]; then
    $bin/mkbootfs $ramdisk > ramdisk-new.cpio;
  else
    cd $ramdisk;
    find . | cpio -H newc -o > $home/ramdisk-new.cpio;
  fi;
  test $? != 0 && packfail=1;

  cd $home;
  if [ "$comp" ]; then
    $bin/magiskboot compress=$comp ramdisk-new.cpio;
    if [ $? != 0 ]; then
      echo "Attempting with busybox $comp..." >&2;
      $comp -9c ramdisk-new.cpio > ramdisk-new.cpio.$comp;
      test $? != 0 && packfail=1;
      rm -f ramdisk-new.cpio;
    fi;
  fi;
  if [ "$packfail" ]; then
    abort "Repacking ramdisk failed. Aborting...";
  fi;

  if [ -f "$bin/mkmtkhdr" -a -f "$split_img/boot.img-base" ]; then
    mtktype=$(od -ta -An -N8 -j8 $split_img/ramdisk.cpio.gz-mtk | sed -e 's/ nul//g' -e 's/   //g' | tr '[:upper:]' '[:lower:]');
    case $mtktype in
      rootfs|recovery) $bin/mkmtkhdr --$mtktype ramdisk-new.cpio*;;
    esac;
  fi;
}

# flash_boot (build, sign and write image only)
flash_boot() {
  local varlist kernel ramdisk cmdline part0 part1 pk8 cert avbtype;

  cd $split_img;
  if [ -f "$bin/mkimage" ]; then
    varlist="name arch os type comp addr ep";
  elif [ -f "$bin/mkbootimg" -a -f "$bin/unpackelf" -a -f boot.img-base ]; then
    mv -f cmdline.txt boot.img-cmdline;
    varlist="cmdline base pagesize kerneloff ramdiskoff tagsoff";
  fi;
  for i in $varlist; do
    if [ -f boot.img-$i ]; then
      eval local $i=\"$(cat boot.img-$i)\";
    fi;
  done;

  cd $home;
  for i in zImage zImage-dtb Image Image-dtb Image.gz Image.gz-dtb Image.bz2 Image.bz2-dtb Image.lzo Image.lzo-dtb Image.lzma Image.lzma-dtb Image.xz Image.xz-dtb Image.lz4 Image.lz4-dtb Image.fit; do
    if [ -f $i ]; then
      kernel=$home/$i;
      break;
    fi;
  done;
  if [ "$kernel" ]; then
    if [ -f "$bin/mkmtkhdr" -a -f "$split_img/boot.img-base" ]; then
      $bin/mkmtkhdr --kernel $kernel;
      kernel=$kernel-mtk;
    fi;
  elif [ "$(ls $split_img/kernel*)" ]; then
    kernel=$(ls $split_img/kernel* | grep -v 'kernel_dtb' | tail -n1);
  fi;
  if [ "$(ls ramdisk-new.cpio*)" ]; then
    ramdisk=$home/$(ls ramdisk-new.cpio* | tail -n1);
  elif [ -f "$bin/mkmtkhdr" -a -f "$split_img/boot.img-base" ]; then
    ramdisk=$split_img/ramdisk.cpio.gz-mtk;
  else
    ramdisk=$(ls $split_img/ramdisk.cpio* | tail -n1);
  fi;
  for fdt in dt recovery_dtbo dtb; do
    for i in $home/$fdt $home/$fdt.img $split_img/$fdt; do
      if [ -f $i ]; then
        eval local $fdt=$i;
        break;
      fi;
    done;
  done;

  cd $split_img;
  if [ -f "$bin/mkimage" ]; then
    test "$comp" == "uncompressed" && comp=none;
    part0=$kernel;
    case $type in
      Multi) part1=":$ramdisk";;
      RAMDisk) part0=$ramdisk;;
    esac;
    $bin/mkimage -A $arch -O $os -T $type -C $comp -a $addr -e $ep -n "$name" -d $part0$part1 $home/boot-new.img;
  elif [ -f "$bin/elftool" ]; then
    test "$dt" && dt="$dt,rpm";
    test -f cmdline.txt && cmdline="cmdline.txt@cmdline";
    $bin/elftool pack -o $home/boot-new.img header=elftool_out/header $kernel $ramdisk,ramdisk $dt $cmdline;
  elif [ -f "$bin/mboot" ]; then
    cp -f $kernel kernel;
    cp -f $ramdisk ramdisk.cpio.gz;
    $bin/mboot -d $split_img -f $home/boot-new.img;
  elif [ -f "$bin/rkcrc" ]; then
    $bin/rkcrc -k $ramdisk $home/boot-new.img;
  elif [ -f "$bin/mkbootimg" -a -f "$bin/unpackelf" -a -f boot.img-base ]; then
    test "$dt" && dt="--dt $dt";
    $bin/mkbootimg --kernel $kernel --ramdisk $ramdisk --cmdline "$cmdline" --base $home --pagesize $pagesize --kernel_offset $kerneloff --ramdisk_offset $ramdiskoff --tags_offset "$tagsoff" $dt --output $home/boot-new.img;
  else
    cp -f $kernel kernel;
    cp -f $ramdisk ramdisk.cpio;
    case $kernel in
      *-dtb) rm -f kernel_dtb;;
    esac;
    test "$dt" -a -f extra && cp -f $dt extra;
    for i in dtb recovery_dtbo; do
      test "$(eval echo \$$i)" -a -f $i && cp -f $(eval echo \$$i) $i;
    done;
    $bin/magiskboot repack $bootimg $home/boot-new.img;
  fi;
  if [ $? != 0 ]; then
    abort "Repacking image failed. Aborting...";
  fi;

  cd $home;
  if [ -f "$bin/futility" -a -d "$bin/chromeos" ]; then
    $bin/futility vbutil_kernel --pack boot-new-signed.img --keyblock $bin/chromeos/kernel.keyblock --signprivate $bin/chromeos/kernel_data_key.vbprivk --version 1 --vmlinuz boot-new.img --bootloader $bin/chromeos/empty --config $bin/chromeos/empty --arch arm --flags 0x1;
    if [ $? != 0 ]; then
      abort "Signing image failed. Aborting...";
    fi;
    mv -f boot-new-signed.img boot-new.img;
  fi;
  if [ -f "$bin/BootSignature_Android.jar" -a -d "$bin/avb" ]; then
    pk8=$(ls $bin/avb/*.pk8);
    cert=$(ls $bin/avb/*.x509.*);
    case $block in
      *recovery*|*SOS*) avbtype=recovery;;
      *) avbtype=boot;;
    esac;
    if [ "$(/system/bin/dalvikvm -Xbootclasspath:/system/framework/core-oj.jar:/system/framework/core-libart.jar:/system/framework/conscrypt.jar:/system/framework/bouncycastle.jar -Xnodex2oat -Xnoimage-dex2oat -cp $bin/BootSignature_Android.jar com.android.verity.BootSignature -verify boot.img 2>&1 | grep VALID)" ]; then
      /system/bin/dalvikvm -Xbootclasspath:/system/framework/core-oj.jar:/system/framework/core-libart.jar:/system/framework/conscrypt.jar:/system/framework/bouncycastle.jar -Xnodex2oat -Xnoimage-dex2oat -cp $bin/BootSignature_Android.jar com.android.verity.BootSignature /$avbtype boot-new.img $pk8 $cert boot-new-signed.img;
      if [ $? != 0 ]; then
        abort "Signing image failed. Aborting...";
      fi;
    fi;
    mv -f boot-new-signed.img boot-new.img;
  fi;

  if [ ! -f boot-new.img ]; then
    abort "Repacked image could not be found. Aborting...";
  elif [ "$(wc -c < boot-new.img)" -gt "$(wc -c < boot.img)" ]; then
    abort "New image larger than boot partition. Aborting...";
  fi;
  if [ -f "$bin/flash_erase" -a -f "$bin/nandwrite" ]; then
    $bin/flash_erase $block 0 0;
    $bin/nandwrite -p $block boot-new.img;
  elif [ "$customdd" ]; then
    dd if=/dev/zero of=$block $customdd 2>/dev/null;
    dd if=boot-new.img of=$block $customdd;
  else
    cat boot-new.img /dev/zero > $block 2>/dev/null || true;
  fi;
  if [ $? != 0 ]; then
    abort "Flashing image failed. Aborting...";
  fi;
}

# flash_dtbo (flash dtbo only)
flash_dtbo() {
  local i dtbo dtboblock;

  cd $home;
  for i in dtbo dtbo.img; do
    if [ -f $i ]; then
      dtbo=$i;
      break;
    fi;
  done;

  if [ "$dtbo" ]; then
    dtboblock=/dev/block/bootdevice/by-name/dtbo$slot;
    if [ ! -e "$dtboblock" ]; then
      abort "dtbo partition could not be found. Aborting...";
    fi;
    if [ -f "$bin/flash_erase" -a -f "$bin/nandwrite" ]; then
      $bin/flash_erase $dtboblock 0 0;
      $bin/nandwrite -p $dtboblock $dtbo;
    elif [ "$customdd" ]; then
      dd if=/dev/zero of=$dtboblock 2>/dev/null;
      dd if=$dtbo of=$dtboblock;
    else
      cat $dtbo /dev/zero > $dtboblock 2>/dev/null || true;
    fi;
    if [ $? != 0 ]; then
      abort "Flashing dtbo failed. Aborting...";
    fi;
  fi;
}
### write_boot (repack ramdisk then build, sign and write image and dtbo)
write_boot() {
  repack_ramdisk;
  flash_boot;
  flash_dtbo;
}
###

### file editing functions:
# backup_file <file>
backup_file() { test ! -f $1~ && cp -fp $1 $1~; }

# restore_file <file>
restore_file() { test -f $1~ && cp -fp $1~ $1; rm -f $1~; }

# replace_string <file> <if search string> <original string> <replacement string> <scope>
replace_string() {
  test "$5" == "global" && local scope=g;
  if ! grep -q "$2" $1; then
    sed -i "s;${3};${4};${scope}" $1;
  fi;
}

# replace_section <file> <begin search string> <end search string> <replacement string>
replace_section() {
  local begin endstr last end;
  begin=$(grep -n "$2" $1 | head -n1 | cut -d: -f1);
  if [ "$begin" ]; then
    if [ "$3" == " " -o ! "$3" ]; then
      endstr='^[[:space:]]*$';
      last=$(wc -l $1 | cut -d\  -f1);
    else
      endstr="$3";
    fi;
    for end in $(grep -n "$endstr" $1 | cut -d: -f1) $last; do
      if [ "$end" ] && [ "$begin" -lt "$end" ]; then
        sed -i "${begin},${end}d" $1;
        test "$end" == "$last" && echo >> $1;
        sed -i "${begin}s;^;${4}\n;" $1;
        break;
      fi;
    done;
  fi;
}

# remove_section <file> <begin search string> <end search string>
remove_section() {
  local begin endstr last end;
  begin=$(grep -n "$2" $1 | head -n1 | cut -d: -f1);
  if [ "$begin" ]; then
    if [ "$3" == " " -o ! "$3" ]; then
      endstr='^[[:space:]]*$';
      last=$(wc -l $1 | cut -d\  -f1);
    else
      endstr="$3";
    fi;
    for end in $(grep -n "$endstr" $1 | cut -d: -f1) $last; do
      if [ "$end" ] && [ "$begin" -lt "$end" ]; then
        sed -i "${begin},${end}d" $1;
        break;
      fi;
    done;
  fi;
}

# insert_line <file> <if search string> <before|after> <line match string> <inserted line>
insert_line() {
  local offset line;
  if ! grep -q "$2" $1; then
    case $3 in
      before) offset=0;;
      after) offset=1;;
    esac;
    line=$((`grep -n "$4" $1 | head -n1 | cut -d: -f1` + offset));
    if [ -f $1 -a "$line" ] && [ "$(wc -l $1 | cut -d\  -f1)" -lt "$line" ]; then
      echo "$5" >> $1;
    else
      sed -i "${line}s;^;${5}\n;" $1;
    fi;
  fi;
}

# replace_line <file> <line replace string> <replacement line>
replace_line() {
  if grep -q "$2" $1; then
    local line=$(grep -n "$2" $1 | head -n1 | cut -d: -f1);
    sed -i "${line}s;.*;${3};" $1;
  fi;
}

# remove_line <file> <line match string>
remove_line() {
  if grep -q "$2" $1; then
    local line=$(grep -n "$2" $1 | head -n1 | cut -d: -f1);
    sed -i "${line}d" $1;
  fi;
}

# prepend_file <file> <if search string> <patch file>
prepend_file() {
  if ! grep -q "$2" $1; then
    echo "$(cat $patch/$3 $1)" > $1;
  fi;
}

# insert_file <file> <if search string> <before|after> <line match string> <patch file>
insert_file() {
  local offset line;
  if ! grep -q "$2" $1; then
    case $3 in
      before) offset=0;;
      after) offset=1;;
    esac;
    line=$((`grep -n "$4" $1 | head -n1 | cut -d: -f1` + offset));
    sed -i "${line}s;^;\n;" $1;
    sed -i "$((line - 1))r $patch/$5" $1;
  fi;
}

# append_file <file> <if search string> <patch file>
append_file() {
  if ! grep -q "$2" $1; then
    echo -ne "\n" >> $1;
    cat $patch/$3 >> $1;
    echo -ne "\n" >> $1;
  fi;
}

# replace_file <file> <permissions> <patch file>
replace_file() {
  cp -pf $patch/$3 $1;
  chmod $2 $1;
}

# patch_fstab <fstab file> <mount match name> <fs match type> block|mount|fstype|options|flags <original string> <replacement string>
patch_fstab() {
  local entry part newpart newentry;
  entry=$(grep "$2" $1 | grep "$3");
  if [ ! "$(echo "$entry" | grep "$6")" -o "$6" == " " -o ! "$6" ]; then
    case $4 in
      block) part=$(echo "$entry" | awk '{ print $1 }');;
      mount) part=$(echo "$entry" | awk '{ print $2 }');;
      fstype) part=$(echo "$entry" | awk '{ print $3 }');;
      options) part=$(echo "$entry" | awk '{ print $4 }');;
      flags) part=$(echo "$entry" | awk '{ print $5 }');;
    esac;
    newpart=$(echo "$part" | sed -e "s;${5};${6};" -e "s; ;;g" -e 's;,\{2,\};,;g' -e 's;,*$;;g' -e 's;^,;;g');
    newentry=$(echo "$entry" | sed "s;${part};${newpart};");
    sed -i "s;${entry};${newentry};" $1;
  fi;
}

# patch_cmdline <cmdline entry name> <replacement string>
patch_cmdline() {
  local cmdfile cmdtmp match;
  if [ -f "$split_img/cmdline.txt" ]; then
    cmdfile=$split_img/cmdline.txt;
  else
    cmdfile=$home/cmdtmp;
    grep "^cmdline=" $split_img/header | cut -d= -f2- > $cmdfile;
  fi;
  if ! grep -q "$1" $cmdfile; then
    cmdtmp=$(cat $cmdfile);
    echo "$cmdtmp $2" > $cmdfile;
    sed -i -e 's;  *; ;g' -e 's;[ \t]*$;;' $cmdfile;
  else
    match=$(grep -o "$1.*$" $cmdfile | cut -d\  -f1);
    sed -i -e "s;${match};${2};" -e 's;  *; ;g' -e 's;[ \t]*$;;' $cmdfile;
  fi;
  if [ -f "$home/cmdtmp" ]; then
    sed -i "s|^cmdline=.*|cmdline=$(cat $cmdfile)|" $split_img/header;
    rm -f $cmdfile;
  fi;
}

# patch_prop <prop file> <prop name> <new prop value>
patch_prop() {
  if ! grep -q "^$2=" $1; then
    echo -ne "\n$2=$3\n" >> $1;
  else
    local line=$(grep -n "^$2=" $1 | head -n1 | cut -d: -f1);
    sed -i "${line}s;.*;${2}=${3};" $1;
  fi;
}

# patch_ueventd <ueventd file> <device node> <permissions> <chown> <chgrp>
patch_ueventd() {
  local file dev perm user group newentry line;
  file=$1; dev=$2; perm=$3; user=$4;
  shift 4;
  group="$@";
  newentry=$(printf "%-23s   %-4s   %-8s   %s\n" "$dev" "$perm" "$user" "$group");
  line=$(grep -n "$dev" $file | head -n1 | cut -d: -f1);
  if [ "$line" ]; then
    sed -i "${line}s;.*;${newentry};" $file;
  else
    echo -ne "\n$newentry\n" >> $file;
  fi;
}
###

### configuration/setup functions:
# reset_ak [keep]
reset_ak() {
  local i;

  if [ ! "$1" == "keep" ]; then
    rm -rf $(dirname $home/*-files/current)/ramdisk;
    for i in $bootimg $patch $ramdisk $split_img $home/rdtmp $home/*-new*; do
      cp -af $i $(dirname $home/*-files/current);
    done;
  fi;
  rm -rf $bootimg $ramdisk $split_img $home/*-new* $home/*-files/current;

  if [ "$1" == "keep" ]; then
    mv -f $home/rdtmp $ramdisk;
  else
    rm -rf $patch $home/rdtmp;
  fi;
  setup_ak;
}

# setup_ak
setup_ak() {
  # allow multi-partition ramdisk modifying configurations (using reset_ak)
  if [ ! -d "$ramdisk" -a ! -d "$patch" ]; then
    if [ -d "$(basename $block)-files" ]; then
      cp -af $home/$(basename $block)-files/* $home;
    else
      mkdir -p $home/$(basename $block)-files;
    fi;
    touch $home/$(basename $block)-files/current;
  fi;
  test ! -d "$ramdisk" && mkdir -p $ramdisk;

  # slot detection enabled by is_slot_device=1 or auto (from anykernel.sh)
  case $is_slot_device in
    1|auto)
      slot=$(getprop ro.boot.slot_suffix 2>/dev/null);
      test "$slot" || slot=$(grep -o 'androidboot.slot_suffix=.*$' /proc/cmdline | cut -d\  -f1 | cut -d= -f2);
      if [ ! "$slot" ]; then
        slot=$(getprop ro.boot.slot 2>/dev/null);
        test "$slot" || slot=$(grep -o 'androidboot.slot=.*$' /proc/cmdline | cut -d\  -f1 | cut -d= -f2);
        test "$slot" && slot=_$slot;
      fi;
      if [ "$slot" ]; then
        case $slot_select in
          inactive)
            case $slot in
              _a) slot=_b;;
              _b) slot=_a;;
            esac;
          ;;
        esac;
      fi;
      if [ ! "$slot" -a "$is_slot_device" == 1 ]; then
        abort "Unable to determine active boot slot. Aborting...";
      fi;
    ;;
  esac;

  # target block partition detection enabled by block=boot recovery or auto (from anykernel.sh)
  case $block in
     auto|"") block=boot;;
  esac;
  case $block in
    boot|recovery)
      case $block in
        boot) parttype="ramdisk boot BOOT LNX android_boot KERN-A kernel KERNEL";;
        recovery) parttype="ramdisk_recovey recovery RECOVERY SOS android_recovery";;
      esac;
      for name in $parttype; do
        for part in $name $name$slot; do
          if [ "$(grep -w "$part" /proc/mtd 2> /dev/null)" ]; then
            mtdmount=$(grep -w "$part" /proc/mtd);
            mtdpart=$(echo $mtdmount | cut -d\" -f2);
            if [ "$mtdpart" == "$part" ]; then
              mtd=$(echo $mtdmount | cut -d: -f1);
            else
              abort "Unable to determine mtd $block partition. Aborting...";
            fi;
            target=/dev/mtd/$mtd;
          elif [ -e /dev/block/by-name/$part ]; then
            target=/dev/block/by-name/$part;
          elif [ -e /dev/block/bootdevice/by-name/$part ]; then
            target=/dev/block/bootdevice/by-name/$part;
          elif [ -e /dev/block/platform/*/by-name/$part ]; then
            target=/dev/block/platform/*/by-name/$part;
          elif [ -e /dev/block/platform/*/*/by-name/$part ]; then
            target=/dev/block/platform/*/*/by-name/$part;
          fi;
          test -e "$target" && break 2;
        done;
      done;
      if [ "$target" ]; then
        block=$(ls $target 2>/dev/null);
      else
        abort "Unable to determine $block partition. Aborting...";
      fi;
    ;;
    *)
      if [ "$slot" ]; then
        test -e "$block$slot" && block=$block$slot;
      fi;
    ;;
  esac;
}
###

### end methods

setup_ak;