#!/bin/sh

# Copyright (c) 2013 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.

# 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"