#!/bin/sh -e

. /scripts/env-setup
. /scripts/helper-utils

__info "Ferrochrome minimal initrd starting ..."

mkdir -p /proc && mount -t proc -o nodev,noexec,nosuid proc /proc \
  || __error "Failed to mount /proc"
mkdir -p /sys && mount -t sysfs -o nodev,noexec,nosuid sysfs /sys \
  || __error "Failed to mount /sys"
mkdir -p /dev && mount -t devtmpfs -o noexec,nosuid,mode=0755 devtmpfs /dev \
  || __error "Failed to mount /dev"

early_load_modules || __error "Failed to load early modules"

mdev -s || __warning "Failed mdev invocation"

ROOT_DEV=""
REAL_INIT="/sbin/init"

for param in $(cat /proc/cmdline); do
  case "$param" in
    root=*) ROOT_DEV="${param#root=}" ;;
    init=*) REAL_INIT="${param#init=}" ;;
  esac
done

[ -n "$ROOT_DEV" ] || __error "No root=... specified in the kernel cmdline"
for i in $(seq 1 10); do
  [ -b "$ROOT_DEV" ] && break
  __info "Waiting for root device $ROOT_DEV ..."
  sleep "0.5s"
done
[ -b "$ROOT_DEV" ] || __error "$ROOT_DEV not found after 5 seconds"
mkdir -p /newroot && mount -t auto "$ROOT_DEV" /newroot \
  || __error "Failed to mount $ROOT_DEV"

if [ -n "$KERNEL_EXTRAS_UUID" ]; then
  KERNEL_EXTRAS_DEV="$(blkid | grep "$KERNEL_EXTRAS_UUID" | cut -d: -f1)"
  KERNEL_EXTRAS_ROOT="/newroot/opt/kernel_extras"

  mkdir -p "$KERNEL_EXTRAS_ROOT" \
    && mount -t auto "$KERNEL_EXTRAS_DEV" "$KERNEL_EXTRAS_ROOT" \
    || __error "Failed to mount kernel extras from $KERNEL_EXTRAS_DEV"

  __info "Symlinking kernel extras into rootfs ..."
  if [ -d "$KERNEL_EXTRAS_ROOT/lib/modules" ]; then
    for module_dir in "$KERNEL_EXTRAS_ROOT/lib/modules"/* ; do
      base_dir="$(basename "$module_dir")"

      # NOTE: Debian enforced merged /usr now: https://wiki.debian.org/UsrMerge.
      lib_dir="/newroot/lib"
      [ ! -L "$lib_dir" ] || lib_dir="/newroot/usr/lib"

      mkdir -p "$lib_dir/modules" \
        && ln -sfv "/opt/kernel_extras/lib/modules/$base_dir" \
                   "$lib_dir/modules/$base_dir" \
        || __warning "Failed to symlink $module_dir"
    done
  fi
  if [ -d "$KERNEL_EXTRAS_ROOT/usr/lib" ]; then
    for dtb_dir in "$KERNEL_EXTRAS_ROOT/usr/lib"/* ; do
      base_dir="$(basename "$dtb_dir")"
      mkdir -p "/newroot/usr/lib" \
        && ln -sfv "/opt/kernel_extras/usr/lib/$base_dir" \
                   "/newroot/usr/lib/$base_dir" \
        || __warning "Failed to symlink $dtb_dir"
    done
  fi
  if [ -d "$KERNEL_EXTRAS_ROOT/usr/src" ]; then
    for header_dir in "$KERNEL_EXTRAS_ROOT/usr/src"/* ; do
      base_dir="$(basename "$header_dir")"
      mkdir -p "/newroot/usr/src" \
        && ln -sfv "/opt/kernel_extras/usr/src/$base_dir" \
                   "/newroot/usr/src/$base_dir" \
        || __warning "Failed to symlink $header_dir"
    done
  fi
else
  __warning "KERNEL_EXTRAS_UUID not specified, not mounting kernel extras"
fi

sync

[ ! -L "/newroot/$REAL_INIT" ] || REAL_INIT="$(readlink "/newroot/$REAL_INIT")"
[ -x "/newroot/$REAL_INIT" ] || __error "Failed to find $REAL_INIT in $ROOT_DEV"

__info "Switching to $REAL_INIT in $ROOT_DEV ..."
exec switch_root /newroot "$REAL_INIT" || __error "Failed to switch root"

__error "Unexpected error; should not reach here"