modmanager

#!/system/bin/sh

PRELOAD_D=/opt/etc/preload.d/

if [ $# -eq 0 ]; then
    sh $0 help
    exit 1
fi

if [ $1 = "enable" ]; then
  if [ $# -ne 3 ]; then 
    echo "illegal number of parameters"
    sh $0 help
    exit 1
  fi
  
  target="$2"
  modlib="lib$3.so"

  if [[ ! -f "${PRELOAD_D}${modlib}" ]] && [[ ! -L "${PRELOAD_D}${modlib}" ]]; then 
    echo "mod not found at ${PRELOAD_D}${modlib}"
    exit 2
  fi
  
  if [[ -L "${PRELOAD_D}${target}" ]]; then
    target=$(basename $(readlink "${PRELOAD_D}${target}"))
  elif [[ ! -d "${PRELOAD_D}${target}" ]]; then
    mkdir -p "${PRELOAD_D}${target}"
  fi

  if [[ -f "${PRELOAD_D}${target}/${modlib}" ]]; then
    exit 0
  fi

  ln -sf "${PRELOAD_D}${modlib}" "${PRELOAD_D}${target}/${modlib}" 

  #this will force init to reload the service, which should auto enable it
  killall ${target} > /dev/null 2>&1 || true
  killall ${target}_original > /dev/null 2>&1 || true

elif  [ $1 = "disable" ]; then
  if [ $# -ne 3 ]; then 
    echo "illegal number of parameters"
    sh $0 help
    exit 1
  fi

  target="$2"
  modlib="lib$3.so"

  if [[ -L "${PRELOAD_D}${target}" ]]; then
    target=$(basename $(readlink "${PRELOAD_D}${target}"))
  elif [[ ! -d "${PRELOAD_D}${target}" ]]; then
    mkdir -p "${PRELOAD_D}${target}"
  fi

  if [[ -L "${PRELOAD_D}${target}/${modlib}" ]]; then
    rm -f "${PRELOAD_D}${target}/${modlib}"
    killall ${target} > /dev/null 2>&1 || true
    killall ${target}_original > /dev/null 2>&1 || true
  else
    echo "no such mod enabled"
  fi
  
elif  [ $1 = "list" ]; then
  if [ $# -eq 1 ]; then 
    echo "mods available:"
    find ${PRELOAD_D} -name "*.so" -maxdepth 1 -exec basename {} \; | busybox sed -r 's/^lib(.*).so$/\1/'
  elif [ $# -eq 2 ]; then
    echo "mods enabled for ${2}:"
    find ${PRELOAD_D}${2}/ -name "*.so" -maxdepth 1 -type l -exec basename {} \; | busybox sed -r 's/^lib(.*).so$/\1/'
  fi
else 
echo "usage: 'modmanager command [args]' where command is one of
  - enable target_name mod_name
  - disable target_name mod_name
  - list [target_name]

  target_name is the name of the service, eg. dji_glasses
  for your convience you may use the aliases 'diy_glasses' 
  and 'fpv_glasses'.

  mod_name is the name of your mod, where the associated
  'lib\${mod_name}.so' must be linked to (or located in)
  /opt/etc/preload.d/
" 

fi