# -*- coding: utf-8 -*-
"""Text parser plugin for Advanced Packaging Tool (APT) History log files."""
import pyparsing
from dfdatetime import time_elements as dfdatetime_time_elements
from plaso.containers import events
from plaso.lib import errors
from plaso.parsers import text_parser
from plaso.parsers.text_plugins import interface
[docs]class APTHistoryLogEventData(events.EventData):
"""APT History log event data.
Attributes:
command (str): command.
command_line (str): command line.
end_time (dfdatetime.DateTimeValues): date and time the end of the log
entry was added.
error (str): reported error.
packages (str): packages that were affected.
requester (str): user requesting the activity.
start_time (dfdatetime.DateTimeValues): date and time the start of
the log entry was added.
"""
DATA_TYPE = 'linux:apt_history_log:entry'
def __init__(self):
"""Initializes event data."""
super(APTHistoryLogEventData, self).__init__(data_type=self.DATA_TYPE)
self.command = None
self.command_line = None
self.end_time = None
self.error = None
self.packages = None
self.requester = None
self.start_time = None
[docs]class APTHistoryLogTextPlugin(interface.TextPlugin):
"""Text parser plugin for Advanced Packaging Tool (APT) History log files."""
NAME = 'apt_history'
DATA_FORMAT = 'Advanced Packaging Tool (APT) History log file'
ENCODING = 'utf-8'
_TWO_DIGITS = pyparsing.Word(pyparsing.nums, exact=2).setParseAction(
lambda tokens: int(tokens[0], 10))
_FOUR_DIGITS = pyparsing.Word(pyparsing.nums, exact=4).setParseAction(
lambda tokens: int(tokens[0], 10))
_DATE_TIME = pyparsing.Group(
_FOUR_DIGITS + pyparsing.Suppress('-') +
_TWO_DIGITS + pyparsing.Suppress('-') +
_TWO_DIGITS +
_TWO_DIGITS + pyparsing.Suppress(':') +
_TWO_DIGITS + pyparsing.Suppress(':') +
_TWO_DIGITS).setResultsName('date_time')
_END_OF_LINE = pyparsing.Suppress(pyparsing.LineEnd())
# Start-Date: 2019-07-10 16:38:12
_RECORD_START_LINE = (
pyparsing.Literal('Start-Date:') + _DATE_TIME + _END_OF_LINE)
_RECORD_BODY_LINE = (
pyparsing.oneOf([
'Commandline:',
'Downgrade:',
'Error:',
'Install:',
'Purge:',
'Remove:',
'Requested-By:',
'Upgrade:']) +
pyparsing.restOfLine() +
_END_OF_LINE)
# End-Date: 2019-07-10 16:38:10
_RECORD_END_LINE = (
pyparsing.Literal('End-Date:') + _DATE_TIME + _END_OF_LINE)
_LINE_STRUCTURES = [
('record_start', _RECORD_START_LINE),
('record_body', _RECORD_BODY_LINE),
('record_end', _RECORD_END_LINE)]
# APT History logs can start with empty lines.
VERIFICATION_GRAMMAR = pyparsing.ZeroOrMore(_END_OF_LINE) + _RECORD_START_LINE
VERIFICATION_LITERALS = [
'Commandline:', 'Downgrade:', 'Error:', 'Install:', 'Purge:', 'Remove:',
'Requested-By:', 'Start-Date:', 'Upgrade:']
def __init__(self):
"""Initializes a text parser plugin."""
super(APTHistoryLogTextPlugin, self).__init__()
self._event_data = None
def _ParseRecord(self, parser_mediator, key, structure):
"""Parses a pyparsing structure.
Args:
parser_mediator (ParserMediator): mediates interactions between parsers
and other components, such as storage and dfVFS.
key (str): name of the parsed structure.
structure (pyparsing.ParseResults): tokens from a parsed log line.
Raises:
ParseError: if the structure cannot be parsed.
"""
if key == 'record_start':
self._ParseRecordStart(structure)
elif key == 'record_body':
self._ParseRecordBody(structure)
elif key == 'record_end':
self._ParseRecordEnd(parser_mediator, structure)
def _ParseRecordBody(self, structure):
"""Parses a line from the body of a log record.
Args:
structure (pyparsing.ParseResults): structure of tokens derived from
a log entry.
Raises:
ParseError: when the date and time value is missing.
"""
command, body = structure
if command == 'Commandline:':
self._event_data.command_line = body.strip()
elif command == 'Error:':
self._event_data.error = body.strip()
elif command == 'Requested-By:':
self._event_data.requester = body.strip()
elif command in (
'Downgrade:', 'Install:', 'Purge:', 'Remove:', 'Upgrade:'):
self._event_data.command = command[:-1]
self._event_data.packages = body.strip()
def _ParseRecordEnd(self, parser_mediator, structure):
"""Parses the last line of a log record.
Args:
parser_mediator (ParserMediator): mediates interactions between parsers
and other components, such as storage and dfVFS.
structure (pyparsing.ParseResults): structure of tokens derived from
a log entry.
"""
time_elements_structure = self._GetValueFromStructure(
structure, 'date_time')
self._event_data.end_time = self._ParseTimeElements(time_elements_structure)
parser_mediator.ProduceEventData(self._event_data)
self._ResetState()
def _ParseRecordStart(self, structure):
"""Parses the first line of a log record.
Args:
structure (pyparsing.ParseResults): structure of tokens derived from
a log entry.
"""
self._event_data = APTHistoryLogEventData()
time_elements_structure = self._GetValueFromStructure(
structure, 'date_time')
self._event_data.start_time = self._ParseTimeElements(
time_elements_structure)
def _ParseTimeElements(self, time_elements_structure):
"""Parses date and time elements of a log line.
Args:
time_elements_structure (pyparsing.ParseResults): date and time elements
of a log line.
Returns:
dfdatetime.TimeElements: date and time value.
Raises:
ParseError: if a valid date and time value cannot be derived from
the time elements.
"""
try:
year, month, day_of_month, hours, minutes, seconds = (
time_elements_structure)
# Ensure time_elements_tuple is not a pyparsing.ParseResults otherwise
# copy.deepcopy() of the dfDateTime object will fail on Python 3.8 with:
# "TypeError: 'str' object is not callable" due to pyparsing.ParseResults
# overriding __getattr__ with a function that returns an empty string
# when named token does not exist.
time_elements_tuple = (year, month, day_of_month, hours, minutes, seconds)
date_time = dfdatetime_time_elements.TimeElements(
time_elements_tuple=time_elements_tuple)
# APT History logs store date and time values in local time.
date_time.is_local_time = True
return date_time
except (TypeError, ValueError) as exception:
raise errors.ParseError(
'Unable to parse time elements with error: {0!s}'.format(exception))
def _ResetState(self):
"""Resets stored values."""
self._event_data = None
[docs] def CheckRequiredFormat(self, parser_mediator, text_reader):
"""Check if the log record has the minimal structure required by the plugin.
Args:
parser_mediator (ParserMediator): mediates interactions between parsers
and other components, such as storage and dfVFS.
text_reader (EncodedTextReader): text reader.
Returns:
bool: True if this is the correct parser, False otherwise.
"""
# Format verification will be faster on average by checking the presence of
# fixed-text fragments first.
if 'Start-Date: ' not in text_reader.lines:
return False
try:
structure = self._VerifyString(text_reader.lines)
except errors.ParseError:
return False
time_elements_structure = self._GetValueFromStructure(
structure, 'date_time')
try:
self._ParseTimeElements(time_elements_structure)
except errors.ParseError:
return False
self._ResetState()
return True
text_parser.TextLogParser.RegisterPlugin(APTHistoryLogTextPlugin)