#!/usr/bin/python3
# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: t -*-
# vi: set ft=python sts=4 ts=4 sw=4 noet :
#
# This file is part of Fail2Ban.
#
# Fail2Ban is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# Fail2Ban is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Fail2Ban; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
"""
Fail2Ban  reads log file that contains password failure report
and bans the corresponding IP addresses using firewall rules.

This tools can test regular expressions for "fail2ban".

"""

__author__ = "Fail2Ban Developers"
__copyright__ = "Copyright (c) 2004-2008 Cyril Jaquier, 2012-2014 Yaroslav Halchenko"
__license__ = "GPL"

import getopt
import locale
import logging
import os
import shlex
import sys
import time
import time
import urllib.request, urllib.parse, urllib.error
from optparse import OptionParser, Option

from configparser import NoOptionError, NoSectionError, MissingSectionHeaderError

try:
	from systemd import journal
	from fail2ban.server.filtersystemd import FilterSystemd
except ImportError:
	journal = None

from fail2ban.version import version
from fail2ban.client.filterreader import FilterReader
from fail2ban.server.filter import Filter
from fail2ban.server.failregex import RegexException

from fail2ban.helpers import FormatterWithTraceBack, getLogger
# Gets the instance of the logger.
logSys = getLogger("fail2ban")

def debuggexURL(sample, regex):
	q = urllib.parse.urlencode({ 're': regex.replace('<HOST>', '(?&.ipv4)'),
							'str': sample,
							'flavor': 'python' })
	return 'http://www.debuggex.com/?' + q

def shortstr(s, l=53):
	"""Return shortened string
	"""
	if len(s) > l:
		return s[:l-3] + '...'
	return s

def pprint_list(l, header=None):
	if not len(l):
		return
	if header:
		s = "|- %s\n" % header
	else:
		s = ''
	print(s + "|  " + "\n|  ".join(l) + '\n`-')

def file_lines_gen(hdlr):
	for line in hdlr:
		try:
			line = line.decode(fail2banRegex.encoding, 'strict')
		except UnicodeDecodeError:
			if sys.version_info >= (3,): # Python 3 must be decoded
				line = line.decode(fail2banRegex.encoding, 'ignore')
		yield line

def journal_lines_gen(myjournal):
	while True:
		try:
			entry = myjournal.get_next()
		except OSError:
			continue
		if not entry:
			break
		yield FilterSystemd.formatJournalEntry(entry)

def get_opt_parser():
	# use module docstring for help output
	p = OptionParser(
				usage="%s [OPTIONS] <LOG> <REGEX> [IGNOREREGEX]\n" % sys.argv[0] + __doc__
				+ """
LOG:
    string                  a string representing a log line
    filename                path to a log file (/var/log/auth.log)
    "systemd-journal"       search systemd journal (systemd-python required)

REGEX:
    string                  a string representing a 'failregex'
    filename                path to a filter file (filter.d/sshd.conf)

IGNOREREGEX:
    string                  a string representing an 'ignoreregex'
    filename                path to a filter file (filter.d/sshd.conf)

Copyright (c) 2004-2008 Cyril Jaquier, 2008- Fail2Ban Contributors
Copyright of modifications held by their respective authors.
Licensed under the GNU General Public License v2 (GPL).

Written by Cyril Jaquier <cyril.jaquier@fail2ban.org>.
Many contributions by Yaroslav O. Halchenko and Steven Hiscocks.

Report bugs to https://github.com/fail2ban/fail2ban/issues
""",
				version="%prog " + version)

	p.add_options([
		Option("-d", "--datepattern",
			   help="set custom pattern used to match date/times"),
		Option("-e", "--encoding",
			   help="File encoding. Default: system locale"),
		Option("-L", "--maxlines", type=int, default=0,
			   help="maxlines for multi-line regex"),
		Option("-m", "--journalmatch",
			   help="journalctl style matches overriding filter file. "
			   "\"systemd-journal\" only"),
		Option('-l', "--log-level", type="choice",
			   dest="log_level",
			   choices=('heavydebug', 'debug', 'info', 'notice', 'warning', 'error', 'critical'),
			   default=None,
			   help="Log level for the Fail2Ban logger to use"),
		Option("-v", "--verbose", action='store_true',
			   help="Be verbose in output"),
		Option("-D", "--debuggex", action='store_true',
			   help="Produce debuggex.com urls for debugging there"),
		Option("--print-no-missed", action='store_true',
			   help="Do not print any missed lines"),
		Option("--print-no-ignored", action='store_true',
			   help="Do not print any ignored lines"),
		Option("--print-all-matched", action='store_true',
			   help="Print all matched lines"),
		Option("--print-all-missed", action='store_true',
			   help="Print all missed lines, no matter how many"),
		Option("--print-all-ignored", action='store_true',
			   help="Print all ignored lines, no matter how many"),
		Option("-t", "--log-traceback", action='store_true',
			   help="Enrich log-messages with compressed tracebacks"),
		Option("--full-traceback", action='store_true',
			   help="Either to make the tracebacks full, not compressed (as by default)"),
		])

	return p


class RegexStat(object):

	def __init__(self, failregex):
		self._stats = 0
		self._failregex = failregex
		self._ipList = list()

	def __str__(self):
		return "%s(%r) %d failed: %s" \
		  % (self.__class__, self._failregex, self._stats, self._ipList)

	def inc(self):
		self._stats += 1

	def getStats(self):
		return self._stats

	def getFailRegex(self):
		return self._failregex

	def appendIP(self, value):
		self._ipList.append(value)

	def getIPList(self):
		return self._ipList


class LineStats(object):
	"""Just a convenience container for stats
	"""
	def __init__(self):
		self.tested = self.matched = 0
		self.matched_lines = []
		self.missed = 0
		self.missed_lines = []
		self.missed_lines_timeextracted = []
		self.ignored = 0
		self.ignored_lines = []
		self.ignored_lines_timeextracted = []

	def __str__(self):
		return "%(tested)d lines, %(ignored)d ignored, %(matched)d matched, %(missed)d missed" % self

	# just for convenient str
	def __getitem__(self, key):
		return getattr(self, key)


class Fail2banRegex(object):

	def __init__(self, opts):
		self._verbose = opts.verbose
		self._debuggex = opts.debuggex
		self._maxlines = 20
		self._print_no_missed = opts.print_no_missed
		self._print_no_ignored = opts.print_no_ignored
		self._print_all_matched = opts.print_all_matched
		self._print_all_missed = opts.print_all_missed
		self._print_all_ignored = opts.print_all_ignored
		self._maxlines_set = False		  # so we allow to override maxlines in cmdline
		self._datepattern_set = False
		self._journalmatch = None

		self.share_config=dict()
		self._filter = Filter(None)
		self._ignoreregex = list()
		self._failregex = list()
		self._time_elapsed = None
		self._line_stats = LineStats()

		if opts.maxlines:
			self.setMaxLines(opts.maxlines)
		if opts.journalmatch is not None:
			self.setJournalMatch(opts.journalmatch.split())
		if opts.datepattern:
			self.setDatePattern(opts.datepattern)
		if opts.encoding:
			self.encoding = opts.encoding
		else:
			self.encoding = locale.getpreferredencoding()



	def setDatePattern(self, pattern):
		if not self._datepattern_set:
			self._filter.setDatePattern(pattern)
			self._datepattern_set = True
			if pattern is not None:
				print("Use      datepattern : %s" % (
					self._filter.getDatePattern()[1], ))

	def setMaxLines(self, v):
		if not self._maxlines_set:
			self._filter.setMaxLines(int(v))
			self._maxlines_set = True
			print("Use         maxlines : %d" % self._filter.getMaxLines())

	def setJournalMatch(self, v):
		if self._journalmatch is None:
			self._journalmatch = v

	def readRegex(self, value, regextype):
		assert(regextype in ('fail', 'ignore'))
		regex = regextype + 'regex'
		if os.path.isfile(value) or os.path.isfile(value + '.conf'):
			if os.path.basename(os.path.dirname(value)) == 'filter.d':
				## within filter.d folder - use standard loading algorithm to load filter completely (with .local etc.):
				basedir = os.path.dirname(os.path.dirname(value))
				value = os.path.splitext(os.path.basename(value))[0]
				print("Use %11s filter file : %s, basedir: %s" % (regex, value, basedir))
				reader = FilterReader(value, 'fail2ban-regex-jail', {}, share_config=self.share_config, basedir=basedir)
				if not reader.read():
					print("ERROR: failed to load filter %s" % value)
					return False
			else:
				## foreign file - readexplicit this file and includes if possible:
				print("Use %11s file : %s" % (regex, value))
				reader = FilterReader(value, 'fail2ban-regex-jail', {}, share_config=self.share_config)
				reader.setBaseDir(None)
				if not reader.readexplicit():
					print("ERROR: failed to read %s" % value)
					return False
			reader.getOptions(None)
			readercommands = reader.convert()
			regex_values = [
				RegexStat(m[3])
				for m in [x for x in readercommands if x[0] == 'set' and x[2] == "add%sregex" % regextype]]
			# Read out and set possible value of maxlines
			for command in readercommands:
				if command[2] == "maxlines":
					maxlines = int(command[3])
					try:
						self.setMaxLines(maxlines)
					except ValueError:
						print("ERROR: Invalid value for maxlines (%(maxlines)r) " \
							  "read from %(value)s" % locals())
						return False
				elif command[2] == 'addjournalmatch':
					journalmatch = command[3:]
					self.setJournalMatch(journalmatch)
				elif command[2] == 'datepattern':
					datepattern = command[3]
					self.setDatePattern(datepattern)
		else:
			print("Use %11s line : %s" % (regex, shortstr(value)))
			regex_values = [RegexStat(value)]

		setattr(self, "_" + regex, regex_values)
		for regex in regex_values:
			getattr(
				self._filter,
				'add%sRegex' % regextype.title())(regex.getFailRegex())
		return True

	def testIgnoreRegex(self, line):
		found = False
		try:
			ret = self._filter.ignoreLine([(line, "", "")])
			if ret is not None:
				found = True
				regex = self._ignoreregex[ret].inc()
		except RegexException as e:
			print(e)
			return False
		return found

	def testRegex(self, line, date=None):
		orgLineBuffer = self._filter._Filter__lineBuffer
		fullBuffer = len(orgLineBuffer) >= self._filter.getMaxLines()
		try:
			line, ret = self._filter.processLine(line, date, checkAllRegex=True)
			for match in ret:
				# Append True/False flag depending if line was matched by
				# more than one regex
				match.append(len(ret)>1)
				regex = self._failregex[match[0]]
				regex.inc()
				regex.appendIP(match)
		except RegexException as e:
			print(e)
			return False
		except IndexError:
			print("Sorry, but no <HOST> found in regex")
			return False
		for bufLine in orgLineBuffer[int(fullBuffer):]:
			if bufLine not in self._filter._Filter__lineBuffer:
				try:
					self._line_stats.missed_lines.pop(
						self._line_stats.missed_lines.index("".join(bufLine)))
					self._line_stats.missed_lines_timeextracted.pop(
						self._line_stats.missed_lines_timeextracted.index(
							"".join(bufLine[::2])))
				except ValueError:
					pass
				else:
					self._line_stats.matched += 1
					self._line_stats.missed -= 1
		return line, ret

	def process(self, test_lines):
		t0 = time.time()
		for line_no, line in enumerate(test_lines):
			if isinstance(line, tuple):
				line_datetimestripped, ret = fail2banRegex.testRegex(
					line[0], line[1])
				line = "".join(line[0])
			else:
				line = line.rstrip('\r\n')
				if line.startswith('#') or not line:
					# skip comment and empty lines
					continue
				line_datetimestripped, ret = fail2banRegex.testRegex(line)
			is_ignored = fail2banRegex.testIgnoreRegex(line_datetimestripped)

			if is_ignored:
				self._line_stats.ignored += 1
				if not self._print_no_ignored and (self._print_all_ignored or self._line_stats.ignored <= self._maxlines + 1):
					self._line_stats.ignored_lines.append(line)
					self._line_stats.ignored_lines_timeextracted.append(line_datetimestripped)

			if len(ret) > 0:
				assert(not is_ignored)
				self._line_stats.matched += 1
				if self._print_all_matched:
					self._line_stats.matched_lines.append(line)
			else:
				if not is_ignored:
					self._line_stats.missed += 1
					if not self._print_no_missed and (self._print_all_missed or self._line_stats.missed <= self._maxlines + 1):
						self._line_stats.missed_lines.append(line)
						self._line_stats.missed_lines_timeextracted.append(line_datetimestripped)
			self._line_stats.tested += 1

			if line_no % 10 == 0 and self._filter.dateDetector is not None:
				self._filter.dateDetector.sortTemplate()
		self._time_elapsed = time.time() - t0



	def printLines(self, ltype):
		lstats = self._line_stats
		assert(self._line_stats.missed == lstats.tested - (lstats.matched + lstats.ignored))
		lines = lstats[ltype]
		l = lstats[ltype + '_lines']
		if lines:
			header = "%s line(s):" % (ltype.capitalize(),)
			if self._debuggex:
				if ltype == 'missed' or ltype == 'matched':
					regexlist = self._failregex
				else:
					regexlist = self._ignoreregex
				l = lstats[ltype + '_lines_timeextracted']
				if lines < self._maxlines or getattr(self, '_print_all_' + ltype):
					ans = [[]]
					for arg in [l, regexlist]:
						ans = [ x + [y] for x in ans for y in arg ]
					b = [a[0] +  ' | ' + a[1].getFailRegex() + ' |  ' + debuggexURL(a[0], a[1].getFailRegex()) for a in ans]
					pprint_list([x.rstrip() for x in b], header)
				else:
					print("%s too many to print.  Use --print-all-%s " \
						  "to print all %d lines" % (header, ltype, lines))
			elif lines < self._maxlines or getattr(self, '_print_all_' + ltype):
				pprint_list([x.rstrip() for x in l], header)
			else:
				print("%s too many to print.  Use --print-all-%s " \
					  "to print all %d lines" % (header, ltype, lines))

	def printStats(self):
		print()
		print("Results")
		print("=======")

		def print_failregexes(title, failregexes):
			# Print title
			total, out = 0, []
			for cnt, failregex in enumerate(failregexes):
				match = failregex.getStats()
				total += match
				if (match or self._verbose):
					out.append("%2d) [%d] %s" % (cnt+1, match, failregex.getFailRegex()))

				if self._verbose and len(failregex.getIPList()):
					for ip in failregex.getIPList():
						timeTuple = time.localtime(ip[2])
						timeString = time.strftime("%a %b %d %H:%M:%S %Y", timeTuple)
						out.append(
							"    %s  %s%s" % (
								ip[1],
								timeString,
								ip[-1] and " (multiple regex matched)" or ""))

			print("\n%s: %d total" % (title, total))
			pprint_list(out, " #) [# of hits] regular expression")
			return total

		# Print title
		total = print_failregexes("Failregex", self._failregex)
		_ = print_failregexes("Ignoreregex", self._ignoreregex)


		if self._filter.dateDetector is not None:
			print("\nDate template hits:")
			out = []
			for template in self._filter.dateDetector.templates:
				if self._verbose or template.hits:
					out.append("[%d] %s" % (
						template.hits, template.name))
			pprint_list(out, "[# of hits] date format")

		print("\nLines: %s" % self._line_stats, end=' ')
		if self._time_elapsed is not None:
			print("[processed in %.2f sec]" % self._time_elapsed, end=' ')
		print()

		if self._print_all_matched:
			self.printLines('matched')
		if not self._print_no_ignored:
			self.printLines('ignored')
		if not self._print_no_missed:
			self.printLines('missed')

		return True


if __name__ == "__main__":

	parser = get_opt_parser()
	(opts, args) = parser.parse_args()
	if opts.print_no_missed and opts.print_all_missed:
		sys.stderr.write("ERROR: --print-no-missed and --print-all-missed are mutually exclusive.\n\n")
		parser.print_help()
		sys.exit(-1)
	if opts.print_no_ignored and opts.print_all_ignored:
		sys.stderr.write("ERROR: --print-no-ignored and --print-all-ignored are mutually exclusive.\n\n")
		parser.print_help()
		sys.exit(-1)

	print()
	print("Running tests")
	print("=============")
	print()

	fail2banRegex = Fail2banRegex(opts)

	# We need 2 or 3 parameters
	if not len(args) in (2, 3):
		sys.stderr.write("ERROR: provide both <LOG> and <REGEX>.\n\n")
		parser.print_help()
		sys.exit(-1)

	# TODO: taken from -testcases -- move common functionality somewhere
	if opts.log_level is not None: # pragma: no cover
		# so we had explicit settings
		logSys.setLevel(getattr(logging, opts.log_level.upper()))
	else: # pragma: no cover
		# suppress the logging but it would leave unittests' progress dots
		# ticking, unless like with '-l critical' which would be silent
		# unless error occurs
		logSys.setLevel(getattr(logging, 'CRITICAL'))

	# Add the default logging handler
	stdout = logging.StreamHandler(sys.stdout)

	fmt = 'D: %(message)s'

	if opts.log_traceback:
		Formatter = FormatterWithTraceBack
		fmt = (opts.full_traceback and ' %(tb)s' or ' %(tbc)s') + fmt
	else:
		Formatter = logging.Formatter

	# Custom log format for the verbose tests runs
	if opts.verbose: # pragma: no cover
		stdout.setFormatter(Formatter(' %(asctime)-15s %(thread)s' + fmt))
	else: # pragma: no cover
		# just prefix with the space
		stdout.setFormatter(Formatter(fmt))
	logSys.addHandler(stdout)

	cmd_log, cmd_regex = args[:2]

	fail2banRegex.readRegex(cmd_regex, 'fail') or sys.exit(-1)

	if len(args) == 3:
		fail2banRegex.readRegex(args[2], 'ignore') or sys.exit(-1)

	if os.path.isfile(cmd_log):
		try:
			hdlr = open(cmd_log, 'rb')
			print("Use         log file : %s" % cmd_log)
			print("Use         encoding : %s" % fail2banRegex.encoding)
			test_lines = file_lines_gen(hdlr)
		except IOError as e:
			print(e)
			sys.exit(-1)
	elif cmd_log == "systemd-journal":
		if not journal:
			print("Error: systemd library not found. Exiting...")
			sys.exit(-1)
		myjournal = journal.Reader(converters={'__CURSOR': lambda x: x})
		journalmatch = fail2banRegex._journalmatch
		fail2banRegex.setDatePattern(None)
		if journalmatch:
			try:
				for element in journalmatch:
					if element == "+":
						myjournal.add_disjunction()
					else:
						myjournal.add_match(element)
			except ValueError:
				print("Error: Invalid journalmatch: %s" % shortstr(" ".join(journalmatch)))
				sys.exit(-1)
		print("Use    journal match : %s" % " ".join(journalmatch))
		test_lines = journal_lines_gen(myjournal)
	else:
		print("Use      single line : %s" % shortstr(cmd_log))
		test_lines = [ cmd_log ]
	print()

	fail2banRegex.process(test_lines)

	fail2banRegex.printStats() or sys.exit(-1)