#!/usr/bin/sh


# EL8 (grub2 with BootLoaderSpec patches)
#
# kernel options: grub.cfg + grubenv
# kernel options in /boot/loader/entries/*.conf use kernelopts from /boot/grub2/grubenv
# grubby
#   - updates kernelopts in /boot/grub2/grubenv
#   - does not update /etc/default/grub
#   - does not update kernelopts in grub.cfg
# grub.cfg:
#   - UEFI: /etc/grub2-efi.cfg -> /boot/efi/EFI/<os>/grub.cfg
#   - BIOS: /etc/grub2.cfg -> /boot/grub2/grub.cfg


# EL9 + EL10 (grub2 with BootLoaderSpec patches)
#
# kernel options: grub.cfg + /etc/kernel/cmdline + /boot/loader/entries/*.conf
# manually update: /etc/default/grub + /etc/kernel/cmdline
# /etc/kernel/cmdline is not really used
# grub2-mkconfig does not update /boot/loader/entries/*.conf
# grub.cfg:
#   - UEFI: /etc/grub2-efi.cfg -> /boot/efi/EFI/<os>/grub.cfg
#   - BIOS: /etc/grub2.cfg -> /boot/grub2/grub.cfg


# Fedora (grub2 with BootLoaderSpec patches)
#
# kernel options: grub.cfg + /etc/kernel/cmdline + /boot/loader/entries/*.conf
# manually update: /etc/default/grub
# grub2-mkconfig:
#   - updates /boot/loader/entries/*.conf
#   - updates /etc/kernel/cmdline
# grub.cfg:
#   - UEFI/BIOS: /boot/grub2/grub.cfg


# Fedora (systemd-boot)
#
# kernel options: grub.cfg + /boot/efi/loader/entries/*.conf (UEFI only)
# grubby as an updateloaderentries alias:
#   - updates all entries in /boot/efi/loader/entries/*.conf
#   - does not work with multiple parameters at once
#   - does not update /etc/kernel/cmdline


# Complete use case coverage, regardless of boot loaders:
#
#   - update options in /etc/default/grub
#       - regenerate grub.cfg/grubenv
#   - update options in /boot/{efi/}loader/entries/*.conf entries
#   - update options in /etc/kernel/cmdline
#   - cover both UEFI and BIOS case

CMDLINE_ARGS_NVIDIA="rd.driver.blacklist=nouveau rd.driver.blacklist=nova-core"
CMDLINE_ARGS_ALWAYS_REMOVE="nomodeset gfxpayload=vga=normal nouveau.modeset=0 nvidia-drm.modeset=1 nvidia-drm.fbdev=1 modprobe.blacklist=nouveau initcall_blacklist=simpledrm_platform_driver_init"

print_usage() {
cat <<EOF
Tool to add or remove kernel command line options required for proper operation of the Nvidia driver.
Its main use is to be called from the %post/%preun scripts of the Nvidia driver packages, but it can also be used in other contexts, for example in a kickstart file after the drivers have been already installed.

Boot loaders supported:
  - grub 2 with BootLoaderSpec patches (el8, el9, fedora)
  - systemd-boot (fedora)

Usage: nvidia-update-boot post|preun
    post        Adjust necessary kernel command line options
    preun       Remove all kernel command line options

EOF
}

check() {
  if [ ! -f /run/ostree-booted ]; then

    if [ -f /etc/default/grub ]; then

      # Grub 2 is installed
      if [ -d /sys/firmware/efi ]; then
        GRUB_CFG=/etc/grub2-efi.cfg
      else
        GRUB_CFG=/etc/grub2.cfg
      fi

      # Grub 2 with BootLoaderSpec patches, different path than systemd-boot
      BLS_ENTRIES=/boot/loader/entries

      . /etc/default/grub

    elif [ ! -f /etc/default/grub ] && [ -f /etc/kernel/cmdline ]; then

      # systemd-boot is installed, differnt path than Grub 2 with BootLoaderSpec patches
      BLS_ENTRIES=/boot/efi/loader/entries

    else

      echo "Nvidia driver setup: no bootloader configured. Please run 'nvidia-boot-update post' manually."

    fi

  fi
}

post() {

  # Edit GRUB configuration file
  if [ -v GRUB_CFG ]; then

    if [ -z "${GRUB_CMDLINE_LINUX}" ]; then
      echo GRUB_CMDLINE_LINUX=\""$CMDLINE_ARGS_NVIDIA"\" >> /etc/default/grub
    else
      for param in $CMDLINE_ARGS_NVIDIA; do
        echo ${GRUB_CMDLINE_LINUX} | grep -q $param
        [ $? -eq 1 ] && GRUB_CMDLINE_LINUX="${GRUB_CMDLINE_LINUX} ${param}"
      done
      for param in $CMDLINE_ARGS_ALWAYS_REMOVE; do
        echo ${GRUB_CMDLINE_LINUX} | grep -q $param
        [ $? -eq 0 ] && GRUB_CMDLINE_LINUX="$(echo ${GRUB_CMDLINE_LINUX} | sed -e "s/ $param//g")"
      done
      sed -i -e "s|^GRUB_CMDLINE_LINUX=.*|GRUB_CMDLINE_LINUX=\"${GRUB_CMDLINE_LINUX}\"|g" /etc/default/grub
    fi

    grub2-mkconfig -o $GRUB_CFG &>/dev/null

  fi

  # Edit BootLoaderSpec entries
  if [ -v BLS_ENTRIES ]; then

    for config_file in $BLS_ENTRIES/*.conf; do
      for param in $CMDLINE_ARGS_NVIDIA; do
        grep -q $param $config_file
        [ $? -eq 1 ] && sed -i -e "s|^options.*|& $param|" $config_file
      done
      for param in $CMDLINE_ARGS_ALWAYS_REMOVE; do
        grep -q $param $config_file
        [ $? -eq 0 ] && sed -i -e "s| $param||" $config_file
      done
    done

  fi

  # Edit /etc/kernel/cmdline
  if [ -f /etc/kernel/cmdline ]; then
    for param in $CMDLINE_ARGS_NVIDIA; do
      grep -q $param /etc/kernel/cmdline
      [ $? -eq 1 ] && sed -i -e "s|^.*|& $param|" /etc/kernel/cmdline
    done
    for param in $CMDLINE_ARGS_ALWAYS_REMOVE; do
      grep -q $param /etc/kernel/cmdline
      [ $? -eq 0 ] && sed -i -e "s| $param||" /etc/kernel/cmdline
    done
  fi
}

preun() {

  # Edit GRUB configuration file
  if [ -v GRUB_CFG ]; then

    for param in $CMDLINE_ARGS_NVIDIA; do
      echo ${GRUB_CMDLINE_LINUX} | grep -q $param
      [ $? -eq 0 ] && GRUB_CMDLINE_LINUX="$(echo ${GRUB_CMDLINE_LINUX} | sed -e "s/ $param//g")"
    done
    sed -i -e "s|^GRUB_CMDLINE_LINUX=.*|GRUB_CMDLINE_LINUX=\"${GRUB_CMDLINE_LINUX}\"|g" /etc/default/grub

    grub2-mkconfig -o $GRUB_CFG &>/dev/null

  fi

  # Edit BootLoaderSpec entries
  if [ -v BLS_ENTRIES ]; then

    for config_file in $BLS_ENTRIES/*.conf; do
      for param in $CMDLINE_ARGS_NVIDIA; do
        grep -q $param $config_file
        [ $? -eq 0 ] && sed -i -e "s| $param||" $config_file
      done
    done

  fi

  # Edit /etc/kernel/cmdline
  if [ -f /etc/kernel/cmdline ]; then
    for param in $CMDLINE_ARGS_NVIDIA; do
      grep -q $param /etc/kernel/cmdline
      [ $? -eq 0 ] && sed -i -e "s| $param||" /etc/kernel/cmdline
    done
  fi
}

case "$1" in
  post)
    check
    post
    exit 0
    ;;
  preun)
    check
    preun
    exit 0
    ;;
  *)
    print_usage
    exit 0
    ;;
esac