appimage-exec.sh

#!@bash@/bin/bash
set -x
export PATH=/empty
for i in @path@; do PATH=$PATH:$i/bin; done

# src : AppImage
# dest : let's unpack() create the directory
unpack() {
  src=$1
  out=$2
  echo $src $out

  # https://github.com/AppImage/libappimage/blob/ca8d4b53bed5cbc0f3d0398e30806e0d3adeaaab/src/libappimage/utils/MagicBytesChecker.cpp#L45-L63
  eval "$(r2 "$src" -nn -Nqc "p8j 3 @ 8" |
    jq -r '{appimageSignature: (.[:-1]|implode), appimageType: .[-1]}|
      @sh "appimageSignature=\(.appimageSignature) appimageType=\(.appimageType)"')"

  # check AppImage signature
  if [[ "$appimageSignature" != "AI" ]]; then
    echo "Not an appimage."
    exit -1
  fi

  case "$appimageType" in
    1)
        mkdir "$out"
        bsdtar -x -C "$out" -f "$src"
        ;;

    2)
        # multiarch offset one-liner using same method as AppImage
        # see https://gist.github.com/probonopd/a490ba3401b5ef7b881d5e603fa20c93
        offset=$(r2 "$src" -nn -Nqc "pfj.elf_header @ 0" |\
          jq 'map({(.name): .value}) | add | .shoff + (.shnum * .shentsize)')

        unsquashfs -q -d "$out" -o "$offset" "$src"
        chmod go-w "$out"
        ;;

    # 3) get ready, https://github.com/TheAssassin/type3-runtime
    *)  echo "Unsupported AppImage Type: $appimageType"
        exit -2
        ;;
  esac
  # return "$appimageType"
}

apprun() {
  APPIMAGE="$(realpath "$1")"
  shift

  #@coreutils@/bin/
  SHA256="$(sha256sum "$APPIMAGE" | cut -d ' ' -f 1)"
  SQUASHFS_ROOT="''${XDG_CACHE_HOME:-$HOME/.cache}/appimage-run/$SHA256/"

  mkdir -p "$SQUASHFS_ROOT"
  unpack "$APPIMAGE" "$APPDIR"
  export PATH="$PATH:$PWD/usr/bin"

  if [ -n "$APPIMAGE_DEBUG_EXEC" ]; then
    exec "$APPIMAGE_DEBUG_EXEC"
  fi
  src="$SQUASHFS_ROOT/squashfs-root"
}

case $# in
  1) if [[ -d $1 ]]; then
       src=$1
     elif [[ -f $1 ]]; then
       apprun $1
     fi
     ;;
  2) unpack $1 $2
     exit
     ;;
  *) echo "Usage: $0 FILE [OPTION...]"
     echo
     echo 'Options are passed on to the appimage.'
     echo "If you want to execute a custom command in the appimage's environment, set the APPIMAGE_DEBUG_EXEC environment variable."
     exit 1
     ;;
esac

# same in appimageTools
export APPDIR="$src"
export APPIMAGE_SILENT_INSTALL=1
cd "$APPDIR"
exec ./AppRun "$@"