#!/usr/bin/python

#  Author: Donald Miner <dminer@tresys.com>
#
# Copyright (C) 2003 - 2005 Tresys Technology, LLC
#      This program 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, version 2.

"""
	This script generates XML documentation information for layers specified
	by the user.
"""

import sys
import os
import glob
import re

# GLOBALS

# Default values of command line arguments:
directory = "./"
warn = False
meta = "metadata"
layers = []
tunable_files = []
bool_files = []

# Pre compiled regular expressions:

# Matches either an interface or a template declaration. Will give the tuple:
#	("interface" or "template", name)
# Some examples:
#	"interface(`kernel_read_system_state',`"
#	 -> ("interface", "kernel_read_system_state")
#	"template(`base_user_template',`"
#	 -> ("template", "base_user_template")
INTERFACE = re.compile("^\s*(interface|template)\(`(\w*)'")

# Matches either a gen_bool or a gen_tunable statement. Will give the tuple:
#	("tunable" or "bool", name, "true" or "false")
# Some examples:
#	"gen_bool(secure_mode, false)"
#	 -> ("bool", "secure_mode", "false")
#	"gen_tunable(allow_kerberos, false)"
#	 -> ("tunable", "allow_kerberos", "false")
BOOLEAN = re.compile("^\s*gen_(tunable|bool)\(\s*(\w*)\s*,\s*(true|false)\s*\)")

# Matches a XML comment in the policy, which is defined as any line starting
#  with two # and at least one character of white space. Will give the single
#  valued tuple:
#	("comment")
# Some Examples:
#	"## <summary>"
#	 -> ("<summary>")
#	"##		The domain allowed access.	"
#	 -> ("The domain allowed access.")
XML_COMMENT = re.compile("^##\s+(.*?)\s*$")


# FUNCTIONS
def getModuleXML(file_name):
	'''
	Returns the XML data for a module in a list, one line per list item.
	'''

	# Try to open the file, if it cant, just ignore it.
	try:
		module_file = open(file_name, "r")
		module_code = module_file.readlines()
		module_file.close()
	except:
		warning("cannot open file %s for read, skipping" % file_name)
		return []

	module_buf = []

	# Infer the module name, which is the base of the file name.
	module_buf.append("<module name=\"%s\" filename=\"%s\">\n" 
		% (os.path.splitext(os.path.split(file_name)[-1])[0], file_name))

	temp_buf = []
	interface = None

	# finding_header is a flag to denote whether we are still looking
	#  for the XML documentation at the head of the file.
	finding_header = True

	# Get rid of whitespace at top of file
	while(module_code and module_code[0].isspace()):
		module_code = module_code[1:]

	# Go line by line and figure out what to do with it.
	line_num = 0
	for line in module_code:
		line_num += 1
		if finding_header:
			# If there is a XML comment, add it to the temp buffer.
			comment = XML_COMMENT.match(line)
			if comment:
				temp_buf.append(comment.group(1) + "\n")
				continue

			# Once a line that is not an XML comment is reached,
			#  either put the XML out to module buffer as the
			#  module's documentation, or attribute it to an
			#  interface/template.
			elif temp_buf:
				finding_header = False
				interface = INTERFACE.match(line)
				if not interface:
					module_buf += temp_buf
					temp_buf = []
					continue

		# Skip over empty lines
		if line.isspace():
			continue

		# Grab a comment and add it to the temprorary buffer, if it
		#  is there.
		comment = XML_COMMENT.match(line)
		if comment:
			temp_buf.append(comment.group(1) + "\n")
			continue

		# Grab the interface information. This is only not true when
		#  the interface is at the top of the file and there is no
		#  documentation for the module.
		if not interface:
			interface = INTERFACE.match(line)
		if interface:
			# Add the opening tag for the interface/template
			groups = interface.groups()
			module_buf.append("<%s name=\"%s\" lineno=\"%s\">\n" % (groups[0], groups[1], line_num))

			# Add all the comments attributed to this interface to
			#  the module buffer.
			if temp_buf:
				module_buf += temp_buf
				temp_buf = []

			# Add default summaries and parameters so that the
			#  DTD is happy.
			else:
				module_buf.append("<summary>\n")
				module_buf.append("Summary is missing!\n")
				module_buf.append("</summary>\n")
				module_buf.append("<param name=\"?\">\n")
				module_buf.append("Parameter descriptions are missing!\n")
				module_buf.append("</param>\n")

			# Close the interface/template tag.
			module_buf.append("</%s>\n" % interface.group(1))

			interface = None
			continue



	# If the file just had a header, add the comments to the module buffer.
	if finding_header:
		module_buf += temp_buf
	# Otherwise there are some lingering XML comments at the bottom, warn
	#  the user.
	elif temp_buf:
		warning("orphan XML comments at bottom of file %s" % file_name)

	module_buf.append("</module>\n")

	return module_buf

def getLayerXML(directory):
	'''
	Returns the XML documentation for a layer.
	'''

	layer_buf = []

	# Infer the layer name from the directory name.
	layer_buf.append("<layer name=\"%s\">\n" % os.path.basename(directory))

	# Try to open the metadata file for this directory and if it exists,
	# append the contents to the buffer.
	try:
		layer_meta = open(directory+"/"+meta, "r")
		layer_buf += layer_meta.readlines()
		layer_meta.close()
	except:
		warning("cannot open file %s for read, assuming no data"\
			% meta)

	# For each module file in the layer, add its XML.
	for module in glob.glob("%s/*.if" % directory):
		layer_buf += getModuleXML(module)

	layer_buf.append("</layer>\n")

	return layer_buf

def getTunableXML(file_name, kind):
	'''
	Return all the XML for the tunables/bools in the file specified.
	'''

	# Try to open the file, if it cant, just ignore it.
	try:
		tunable_file = open(file_name, "r")
		tunable_code = tunable_file.readlines()
		tunable_file.close()
	except:
		warning("cannot open file %s for read, skipping" % file_name)
		return []

	tunable_buf = []
	temp_buf = []

	# Find tunables and booleans line by line and use the comments above
	# them.
	for line in tunable_code:
		# If it is an XML comment, add it to the buffer and go on.
		comment = XML_COMMENT.match(line)
		if comment:
			temp_buf.append(comment.group(1))
			continue

		# Get the boolean/tunable data.
		boolean = BOOLEAN.match(line)

		# If we reach a boolean/tunable declaration, attribute all XML
		#  in the temp buffer to it and add XML to the tunable buffer.
		if boolean:
			# If there is a gen_bool in a tunable file or a
			# gen_tunable in a boolean file, error and exit.
			if boolean.group(1) != kind:
				error("%s in a %s file." % (boolean.group(1), kind))

			tunable_buf.append("<%s name=\"%s\" dftval=\"%s\">\n" % boolean.groups())
			tunable_buf += temp_buf
			temp_buf = []
			tunable_buf.append("</%s>\n" % boolean.group(1))

	# If there are XML comments at the end of the file, they arn't
	# attributed to anything. These are ignored.
	if len(temp_buf):
		warning("orphan XML comments at bottom of file %s" % file_name)

	return tunable_buf

def getPolicyXML(directory):
	'''
	Return the compelete reference policy XML documentation through a list,
	one line per item.
	'''

	# Keep track of original path so that it will change back at the end.
	old_dir = os.path.abspath(os.path.curdir)

	# Attempt to change directory into the policy directory. If it doesn't
	# exist just return an empty documentation.
	try:
		os.chdir(directory)
	except:
		warning("cannot change directory to %s, ignoring"\
			% directory)
		return []

	policy_buf = []
	policy_buf.append("<policy>\n")

	# Add to the XML each layer specified by the user.
	for layer in layers:
		policy_buf += getLayerXML(layer)

	# Add to the XML each tunable file specified by the user.
	for tunable_file in tunable_files:
		policy_buf += getTunableXML(tunable_file, "tunable")

	# Add to the XML each bool file specified by the user.
	for bool_file in bool_files:
		policy_buf += getTunableXML(bool_file, "bool")


	policy_buf.append("</policy>\n")

	# Return to old directory.
	try:
		os.chdir(old_dir)
	except:
		error("cannot change directory to %s" % old_dir)

	return policy_buf

def usage():
	"""
	Displays a message describing the proper usage of this script.
	"""

	sys.stdout.write("usage: %s [-w] [-d directory] [-m file] "\
		% sys.argv[0])

	sys.stdout.write("layerdirectory [layerdirectory...]\n\n")

	sys.stdout.write("Options:\n")

	sys.stdout.write("-w --warn		--	"+\
				"show warnings\n")

	sys.stdout.write("-m --meta <file>	--	"+\
				"the filename of the metadata in each layer\n")

	sys.stdout.write("-d --directory <dir>	--	"+\
				"directory where the layers are\n")

	sys.stdout.write("-t --tunable <file>	--	"+\
				"A file containing tunable declarations\n")

	sys.stdout.write("-b --bool <file>      --      "+\
				"A file containing bool declarations\n")

def warning(description):
	'''
	Warns the user of a non-critical error.
	'''

	if warn:
		sys.stderr.write("%s: " % sys.argv[0] )
		sys.stderr.write("warning: " + description + "\n")

def error(description):
	'''
	Describes an error and exists the program.
	'''

	sys.stderr.write("%s: " % sys.argv[0] )
        sys.stderr.write("error: " + description + "\n")
        sys.stderr.flush()
        sys.exit(1)



# MAIN PROGRAM
# Check that there are command line arguments.
if len(sys.argv) <= 1:
	usage()
	sys.exit(1)


# Parse the command line arguments
for i in range(1, len(sys.argv)):
	if sys.argv[i-1] in ("-d", "--directory", "-m", "--meta",\
					"-t", "--tunable", "-b", "--bool"):
		continue
	elif sys.argv[i] in ("-w", "--warn"):
		warn = True
	elif sys.argv[i] in ("-d", "--directory"):
		if i < len(sys.argv)-1:
			directory = sys.argv[i+1]
		else:
			usage()
	elif sys.argv[i] in ("-m", "--meta"):
		if i < len(sys.argv)-1:
			meta = sys.argv[i+1]
		else:
			usage()
	elif sys.argv[i] in ("-t", "--tunable"):
		if i < len(sys.argv)-1:
			tunable_files.append(sys.argv[i+1])
		else:
			usage()
	elif sys.argv[i] in ("-b", "--bool"):
		if i < len(sys.argv)-1:
			bool_files.append(sys.argv[i+1])
		else:
			usage()

	else:
		layers.append(sys.argv[i])


# Generate the XML and output it to a file
lines = getPolicyXML(directory)
for s in lines:
	sys.stdout.write(s)