convert dynamic binary to "statically linked"

how.md

./unlink path/to/binary

out/run to call it

unlink.sh

#!/bin/bash
set -e
set -u
set -o pipefail

ELF=$1
TGT=$PWD/${2:-out}

rm -rf "$TGT"
mkdir -p "$TGT"

interpreter=$(readelf -l "$ELF" | grep "Requesting program interpreter")
interpreter=${interpreter#*[:]}
interpreter=${interpreter:1}
interpreter=${interpreter::-1}

resolveelf() {
  local lib
  local needed
  mapfile -t needed <<<"$(readelf -d "$1" | grep "(NEEDED)" | sed -r 's/.*\[(.*)\]/\1/')"

  for lib in "${needed[@]}"; do
    if [ -z "$lib" ]; then
      continue
    fi
    echo "-> $lib"
    libname=$(basename "$lib")

    if [ "$libname" = "$(basename "$interpreter")" ]; then
      continue
    fi

    if [ -f "$TGT/$lib" ]; then
      continue
    fi
    if ! [ -f "$lib" ]; then
      # relative path
      lib=$(ldconfig -p | grep -F "$lib" | head -1)
      lib=${lib//* => /}

      if ! [ "$libname" = "$(basename "$lib")" ]; then
        echo "library name mismatch: $libname -> $lib" # happens with version mismatch, don't know how to handle this
        lib="$(dirname "$lib")/$libname"
      fi
    fi

    resolveelf "$lib"
  done

  cp "$1" "$TGT"

  echo "patching $1"
  for lib in "${needed[@]}"; do
    patchelf --replace-needed "$lib" "./$(basename "$lib")" "$TGT/$(basename "$1")"
  done
}

resolveelf "$ELF"

cp "$interpreter" "$TGT"

patchelf --set-interpreter "./$(basename "$interpreter")" "$TGT/$(basename "$ELF")"

cat <<EOF >"$TGT/run"
#!/bin/sh
cd "\$(dirname "\$0")"
exec "$(basename "$ELF")" "\$@"
EOF
chmod +x "$TGT/run"