#!/bin/sh

# Copyright (C) 2013 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Usage example: "kernel_log_collector.sh XXX YYY"
# This script searches logs in the /var/log/messages which have the keyword XXX.
# And only those logs which are within the last YYY seconds of the latest log
# that has the keyword XXX are printed.

# Kernel log has the possible formats:
# 2013-06-14T16:31:40.514513-07:00 localhost kernel: [    2.682472] MSG MSG ...
# 2013-06-19T20:38:58.661826+00:00 localhost kernel: [    1.668092] MSG MSG ...

search_key=$1
time_duration=$2
msg_pattern="^[0-9-]*T[0-9:.+-]* localhost kernel"

die() {
  echo "kernel_log_collector: $*" >&2
  exit 1
}

get_timestamp() {
  timestamp="$(echo $1 | cut -d " " -f 1)"
  timestamp="$(date -d "${timestamp}" +%s)" || exit $?
  echo "${timestamp}"
}

last_line=$(grep "${msg_pattern}" /var/log/messages | grep -- "${search_key}" | tail -n 1)

if [ -n "${last_line}" ]; then
  if ! allowed_timestamp=$(get_timestamp "${last_line}"); then
    die "coule not get timestamp from: ${last_line}"
  fi
  : $(( allowed_timestamp -= ${time_duration} ))
  grep "${msg_pattern}" /var/log/messages | grep -- "${search_key}" | while read line; do
    if ! timestamp=$(get_timestamp "${line}"); then
      die "could not get timestamp from: ${line}"
    fi
    if [ ${timestamp} -gt ${allowed_timestamp} ]; then
      echo "${line}"
    fi
  done
fi

echo "END-OF-LOG"