recipes-google/boot/gbmc-no-initrd/clean-rwfs.sh.in

#!/bin/bash
shopt -s nullglob
ret=0

rwfs=/tmp/rwfs
cow="$rwfs/cow"
purge_file="$cow"/var/google/do-rwfs-purge
job_id_tmp=/tmp/job-id
done_job_id="$cow"/var/google/rwfs-purged

mount_rwfs() {
  echo 'Mounting RWFS in isolation' >&2
  mount -t jffs2 -o defaults,noatime mtd:rwfs "$rwfs"
}
umount_rwfs() {
  echo 'Unmounting RWFS' >&2
  umount "$@" "$rwfs"
}

mkdir -p "$rwfs" || exit
mount_rwfs || exit

# Keep track of the last version to use this rwfs
version_from_osrelease() {
  grep '^VERSION_ID=' "$1" | sed 's,.*gbmc-release-,,'
}
if ver=$(version_from_osrelease /etc/os-release); then
  echo "Current Release: $ver" >&2
fi
if ver=$(version_from_osrelease "$rwfs"/os-release); then
  echo "Previous Release: $ver" >&2
fi

if [ -e "$purge_file" ]; then
  cp -v "$purge_file" "$job_id_tmp"
  umount_rwfs -f || true
  echo 'Purging RWFS' >&2
  flash_eraseall /dev/$(grep '"rwfs"$' /proc/mtd | sed 's,:.*,,') || ret=$?
  mount_rwfs || ret=$?
  mkdir -p "$(dirname "$done_job_id")"
  cp -v "$job_id_tmp" "$done_job_id"
elif [ '@ALWAYS_CLEAR@' = '1' ] || ! cmp "$rwfs"/os-release /etc/os-release 2>/dev/null; then
  declare -A allowed=()
  while read -r line; do
    allowed["$line/*"]=1
    while [ -n "$line" ]; do
      allowed["$line"]=1
      line="${line%/*}"
    done
  done </usr/share/gbmc-rwfs-allow.list
  # remove everything not in the whitelist.
  # e.g. the whitelist contains a single entry /a/b, the
  # follow command will be generated:
  # find /run/initramfs/rw/cow -mindepth 1 ! -path /run/initramfs/rw/cow/a/b/* ! -path /run/initramfs/rw/cow/a/b ! -path /run/initramfs/rw/cow/a -exec rm -rf {} +
  args=("$cow" -mindepth 1)
  for path in "${!allowed[@]}"; do
    args+=(! -path "$cow$path")
  done
  args+=(-exec rm -rf '{}' '+')
  echo 'Cleaning RWFS' >&2
  if [ -e "$cow" ]; then
    find "${args[@]}" || ret=$?
  fi
fi

if ! cmp /etc/os-release "$rwfs"/os-release 2>/dev/null; then
  cp /etc/os-release "$rwfs"/os-release || ret=$?
fi

umount /tmp/rwfs || ret=$?
exit $ret