Fix Github Copilot agent NixOS

fix_copilot.sh

#! /usr/bin/env nix-shell
#! nix-shell -i bash -p patchelf

## Pass the github copilot agent as first parameter.
## Example: /home/luis/.local/share/JetBrains/CLion2023.1/github-copilot-intellij/copilot-agent/bin/copilot-agent-linux

binaryLocation="$1"

cp "${binaryLocation}" "${binaryLocation}.bak"

orig_size=$(stat --printf=%s "${binaryLocation}")

echo "Orig Size: ${orig_size}"

interpreter=$(nix-shell -I /etc/nix/inputs/ -p gcc --command 'cat $NIX_CC/nix-support/dynamic-linker')
libPath=$(echo "lib.makeLibraryPath [ stdenv.cc.cc ]" | nix repl '<nixpkgs>' 2> /dev/null | tr -d '\n' | cut -d'"' -f 2)

echo "Using interpreter: ${interpreter}"
echo "Using libpath: ${libPath}"

patchelf --set-interpreter "${interpreter}" "${binaryLocation}"
patchelf --set-rpath "${libPath}" "${binaryLocation}"

chmod +x "${binaryLocation}"

new_size=$(stat --printf=%s "${binaryLocation}")

echo "New Size: ${new_size}"

var_skip=20
var_select=22
shift_by=$(expr $new_size - $orig_size)

echo "Diff Size: ${shift_by}"

function fix_offset {
    location=$(grep -obUam1 "$1" "${binaryLocation}" | cut -d: -f1)
    location=$(expr $location + $var_skip)
    
    value=$(dd if="${binaryLocation}" iflag=count_bytes,skip_bytes skip=$location bs=1 count=$var_select status=none)
    value=$(expr $shift_by + $value)
    
    echo -n $value | dd of="${binaryLocation}" bs=1 seek=$location conv=notrunc
}

fix_offset PAYLOAD_POSITION
fix_offset PRELUDE_POSITION