{ pkgs ? import { }, feature, }: pkgs.runCommandNoCC "${feature}-present" { requiredSystemFeatures = [ feature ]; } '' if [[ ! -e /${feature}-files ]]; then echo "The host declares ${feature} support, but doesn't expose /${feature}-files" >&2 exit 1 fi libcudaLocation=/run/opengl-driver/lib/libcuda.so if [[ -e "$libcudaLocation" || -h "$libcudaLocation" ]] ; then true # we're good else echo "The host declares ${feature} support, but it the hook fails to handle the hostPath != guestPath cases" >&2 exit 1 fi if cat "$libcudaLocation" | xargs test fakeContent = ; then true # we're good else echo "The host declares ${feature} support, but it seems to fail to follow symlinks" >&2 echo "The content of /run/opengl-driver/lib/libcuda.so is: $(cat /run/opengl-driver/lib/libcuda.so)" >&2 exit 1 fi touch $out ''