#!/usr/bin/python
# 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".

Report bugs to https://github.com/fail2ban/fail2ban/issues
"""

__author__ = "Cyril Jaquier, Yaroslav Halchenko"
__copyright__ = "Copyright (c) 2004-2008 Cyril Jaquier, 2012-2013 Yaroslav Halchenko"
__license__ = "GPL"

import getopt, sys, time, logging, os

# Inserts our own modules path first in the list
# fix for bug #343821
try:
	from common.version import version
except ImportError, e:
	sys.path.insert(1, "/usr/share/fail2ban")
	from common.version import version

from client.configparserinc import SafeConfigParserWithIncludes
from ConfigParser import NoOptionError, NoSectionError, MissingSectionHeaderError
from server.filter import Filter
from server.failregex import RegexException

from optparse import OptionParser, Option

# Gets the instance of the logger.
logSys = logging.getLogger("fail2ban.regex")

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 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)

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)
""",
				version="%prog " + version)

	p.add_options([
		Option('-l', "--log-level", type="choice",
			   dest="log_level",
			   choices=('debug', 'info', 'warn', 'error', 'fatal'),
			   default=None,
			   help="Log level for the Fail2Ban logger to use"),
		Option("-v", "--verbose", action='store_true',
			   help="Be verbose in output"),
		Option("--print-all-missed", action='store_true',
			   help="Either to print all missed lines"),
		Option("--print-all-ignored", action='store_true',
			   help="Either to print all ignored lines"),

		])

	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.extend(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.missed_lines = []
		self.ignored_lines = []

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

	@property
	def ignored(self):
		return len(self.ignored_lines)

	@property
	def missed(self):
		return self.tested - (self.ignored + self.matched)

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


class Fail2banRegex(object):

	# ???
	test = None

	CONFIG_DEFAULTS = {'configpath' : "/etc/fail2ban/"}

	def __init__(self, opts):
		self._verbose = opts.verbose
		self._print_all_missed = opts.print_all_missed
		self._print_all_ignored = opts.print_all_ignored

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

		# Setup logging
		logging.getLogger("fail2ban").handlers = []
		self._hdlr = logging.StreamHandler(Fail2banRegex.test)
		# set a format which is simpler for console use
		formatter = logging.Formatter("%(message)s")
		# tell the handler to use this format
		self._hdlr.setFormatter(formatter)
		self._logging_level = self._verbose and logging.DEBUG or logging.WARN
		logging.getLogger("fail2ban").addHandler(self._hdlr)
		logging.getLogger("fail2ban").setLevel(logging.ERROR)


	def readRegex(self, value, regextype):
		assert(regextype in ('fail', 'ignore'))
		regex = regextype + 'regex'
		if os.path.isfile(value):
			reader = SafeConfigParserWithIncludes(defaults=self.CONFIG_DEFAULTS)
			try:
				reader.read(value)
				print "Use %11s file : %s" % (regex, value)
				# TODO: reuse functionality in client
				regex_values = [RegexStat(m)
							    for m in reader.get("Definition", regex).split('\n')]
			except NoSectionError:
				print "No [Definition] section in %s" % value
				return False
			except NoOptionError:
				print "No %s option in %s" % (regex, value)
				return False
			except MissingSectionHeaderError:
				print "No section headers in %s" % value
				return False
		else:
			print "Use %11s line : %s" % (regex, shortstr(value))
			regex_values = [RegexStat(value)]

		setattr(self, "_" + regex, regex_values)
		return True

	def testIgnoreRegex(self, line):
		found = False
		for regex in self._ignoreregex:
			logging.getLogger("fail2ban").setLevel(self._logging_level)
			try:
				self._filter.addIgnoreRegex(regex.getFailRegex())
				try:
					ret = self._filter.ignoreLine(line)
					if ret:
						found = True
						regex.inc()
				except RegexException, e:
					print e
					return False
			finally:
				self._filter.delIgnoreRegex(0)
				logging.getLogger("fail2ban").setLevel(self._logging_level)
		return found

	def testRegex(self, line):
		found = False
		for regex in self._ignoreregex:
			self._filter.addIgnoreRegex(regex.getFailRegex())
		for regex in self._failregex:
			# logging.getLogger("fail2ban").setLevel(logging.DEBUG)
			try:
				self._filter.addFailRegex(regex.getFailRegex())
				try:
					ret = self._filter.processLine(line)
					if len(ret):
						if found == True:
							ret[0].append(True)
						else:
							found = True
							ret[0].append(False)
						regex.inc()
						regex.appendIP(ret)
				except RegexException, e:
					print e
					return False
				except IndexError:
					print "Sorry, but no <host> found in regex"
					return False
			finally:
				self._filter.delFailRegex(0)
				logging.getLogger("fail2ban").setLevel(logging.CRITICAL)
		for regex in self._ignoreregex:
			self._filter.delIgnoreRegex(0)
		return found


	def process(self, test_lines):

		for line in test_lines:
			if line.startswith('# ') or not line.strip():
				# skip comment and empty lines
				continue
			is_ignored = fail2banRegex.testIgnoreRegex(line)
			if is_ignored:
				self._line_stats.ignored_lines.append(line)

			if fail2banRegex.testRegex(line):
				assert(not is_ignored)
				self._line_stats.matched += 1
			else:
				if not is_ignored:
					self._line_stats.missed_lines.append(line)
			self._line_stats.tested += 1

	def printLines(self, ltype):
		lstats = self._line_stats
		assert(len(lstats.missed_lines) == lstats.tested - (lstats.matched + lstats.ignored))
		l = lstats[ltype + '_lines']
		if len(l):
			header = "%s line(s):" % (ltype.capitalize(),)
			if len(l) < 20 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, len(l))

	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[1])
						timeString = time.strftime("%a %b %d %H:%M:%S %Y", timeTuple)
						out.append("    %s  %s%s" % (
							ip[0], timeString, ip[2] and " (already 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)


		print "\nDate template hits:"
		out = []
		for template in self._filter.dateDetector.getTemplates():
			if self._verbose or template.getHits():
				out.append("[%d] %s" % (template.getHits(), template.getName()))
		pprint_list(out, "[# of hits] date format")

		print "\nLines: %s" % self._line_stats

		self.printLines('ignored')
		self.printLines('missed')

		return True


if __name__ == "__main__":

	parser = get_opt_parser()
	(opts, args) = parser.parse_args()

	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)

	print
	print "Running tests"
	print "============="
	print

	cmd_log, cmd_regex = args[:2]

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

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

	if os.path.isfile(cmd_log):
		try:
			hdlr = open(cmd_log)
			print "Use         log file : %s" % cmd_log
			test_lines = hdlr.readlines()
		except IOError, e:
			print e
			sys.exit(-1)
	else:
		print "Use      single line : %s" % shortstr(cmd_log)
		test_lines = [ cmd_log ]
	print

	fail2banRegex.process(test_lines)

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