clobber-log

#!/bin/sh

# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This script can maintain a log file across stateful partition wiping
# transition.

CLOBBER_LOG_FILE="clobber.log"

# Temp folder is always accessible (by tmpfs), but stateful partition may be not
# available. To verify that, check the existence of STATEFUL_LOG_FOLDER.
STATEFUL_LOG_FOLDER="/mnt/stateful_partition/unencrypted/"
STATEFUL_LOG_PATH="${STATEFUL_LOG_FOLDER}/${CLOBBER_LOG_FILE}"
TMP_LOG_PATH="/tmp/${CLOBBER_LOG_FILE}"
PSTORE_PATH="/sys/fs/pstore"
RAMOOPS_LOG="${PSTORE_PATH}/console-ramoops"
MAX_KEEP_LOG_LINES=1024
RAMOOPS_DUMP_LINES=128

mount_pstore() {
  # Copied from pstore.conf. clobber-state is always executed before
  # boot-services so pstore.conf won't be ready at that time and we have to
  # mount now.
  if ! mountpoint -q "${PSTORE_PATH}"; then
    mount -n -t pstore -o nodev,nosuid,noexec pstore "${PSTORE_PATH}" || true
  fi
}

log_prefix() {
  echo "$(date --utc '+%Y/%m/%d %H:%M:%S') UTC"
}

preserve_log() {
  # Try to copy log from stateful partition to tmp.
  local source_path="${STATEFUL_LOG_PATH}"
  local dest_path="${TMP_LOG_PATH}"

  # TODO(hungte) store log in some special place, like last sector of stateful
  # partition so that logs won't be lost if user interrupts during wiping.

  if [ -s "${source_path}" ]; then
    tail -n "${MAX_KEEP_LOG_LINES}" "${source_path}" >"${dest_path}"
  else
    echo "No prior clobber-log found" >>"${dest_path}"
  fi
  echo "$(log_prefix) (preserve log): $*" >>"${dest_path}"
}

restore_log() {
  # Try to copy log from tmp back to stateful partition.
  local source_path="${TMP_LOG_PATH}"
  local dest_path="${STATEFUL_LOG_PATH}"
  # the mode should be matched to chromeos_startup.
  mkdir -p -m 0755 "${STATEFUL_LOG_FOLDER}"
  if [ -s "${source_path}" ]; then
    cp "${source_path}" "${dest_path}"
  fi
  echo "$(log_prefix) (restore log): $*" >>"${dest_path}"
}

find_log_path() {
  # Always use log in stateful partition, otherwise create in temp.
  local dest_path="${STATEFUL_LOG_PATH}"
  if [ ! -d "${STATEFUL_LOG_FOLDER}" ]; then
    dest_path="${TMP_LOG_PATH}"
  fi
  echo "${dest_path}"
}

append_log() {
  # Add one line of log into the clobber log file.
  local dest_path
  dest_path="$(find_log_path)"
  echo "$(log_prefix) $*" >>"${dest_path}"
}

append_logfile() {
  # Add MAX_KEEP_LOG_LINES from file into log.
  local dest_path="$(find_log_path)"
  local source_path="$1"

  if [ ! -f "${source_path}" ]; then
    echo "File not found: ${source_path}"
    return
  fi

  echo "-- $(basename ${source_path}) --" >> "${dest_path}"
  tail -n ${MAX_KEEP_LOG_LINES} "${source_path}" >> "${dest_path}"
  echo "-- end of logfile --" >> "${dest_path}"

  echo "$(log_prefix) (append_logfile): $@" >>"$dest_path"
}

repair_log() {
  # Report detail messages for the status of stateful partition.
  local dest_path="${TMP_LOG_PATH}"

  # TODO(hungte) try to recover logs from some where - see preserve_log.

  if [ ! -b "$1" ]; then
    echo "$(log_prefix) repair: $1: invalid device file." >>"${dest_path}"
    return
  fi

  echo "$(log_prefix) (repair): $*" >>"${dest_path}"
  # "fsck -n" and "mount -v" may also help.
  dumpe2fs -fh "$1" >>"${dest_path}" 2>&1

  mount_pstore
  echo "-- Ramoops (logs from last boot):" >>"${dest_path}"
  # There might be more than one record, so grab them all with a glob.
  # Plus, for <linux-3.19, it's named "console-ramoops", but for newer
  # versions, it's named "console-ramoops-#".
  local ramoops
  for ramoops in "${RAMOOPS_LOG}"*; do
    if [ -f "${ramoops}" ]; then
      echo "${ramoops}"
      tail -n "${RAMOOPS_DUMP_LINES}" "${ramoops}" >>"${dest_path}" 2>/dev/null
    else
      echo "(No ramoops found, sorry)" >>"${dest_path}"
    fi
  done

  # try to dump first several blocks
  (
    echo "-- File system $1 block data (gz+base64):"
    dd if="$1" bs=1M count=1 | gzip -c | base64 2>/dev/null
    echo "-- File system $1 block data dump complete."
  ) >>"${dest_path}"
  # to read back the block data, extract to a file and do
  # cat block | base64 -d | gunzip -c -d > block.bin
}

# Process the very limited commands
case "$1" in
  --preserve )
    shift
    preserve_log "$@"
    ;;
  --restore )
    shift
    restore_log "$@"
    ;;
  --repair )
    shift
    repair_log "$@"
    ;;
  --append_logfile )
    shift
    append_logfile "$@"
    ;;
  -- )
    shift
    append_log "$@"
    ;;
  * )
    append_log "$@"
    ;;
esac