# Copyright (C) 2004 Nicolas Delon <nicolas@prelude-ids.org>
# All Rights Reserved
#
# This file is part of the Prelude program.
#
# 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; either version 2, or (at your option)
# any later version.
#
# This program 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 this program; see the file COPYING.  If not, write to
# the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


import MyConfigParser, FileSummary, Input
import glob
import os
from stat import *

MONITORING = "monitoring"
ALIASES = "aliases"

def strpbrk(s, accept):
    "Act like the corresponding C function"
    index = 0
    for c in s:
        if c in accept:
            return index
        index += 1
    return -1



class Error(Exception):
    pass



class UnknownProperty(Error):
    def __init__(self, property, option):
        self.property = property
        self.lineno = option.getLineno()
        self.line = option.getLine()

    def __str__(self):
        return "unknown property '%s' in \"%s\" at line %d" % (self.property, self.line.rstrip(), self.lineno)



class Conf:
    ATTR_TABLE = {
        "protection": FileSummary.MODE,
        "inode": FileSummary.INODE,
        "links": FileSummary.LINKS,
        "uid": FileSummary.UID,
        "gid": FileSummary.GID,
        "mtime": FileSummary.MTIME,
        "atime": FileSummary.ATIME,
        "ctime": FileSummary.CTIME,
        "md5": FileSummary.MD5,
        "sha": FileSummary.SHA,
        }
    
    def __init__(self, filename="../../etc/prelude-fic/prelude-fic.conf"):
        self._filename = filename
        self._files = { }
        self._aliases = { }
        self._load()

    def getFiles(self):
        return self._files.values()

    def __str__(self):
        ret = "[aliases]\n"
        for alias in self._aliases:
            ret += "%s = %#x\n" % (alias, self._aliases[alias])

        ret += "\n[monitoring]\n"
        for file in self._files.values():
            ret += "%s\n" % file
        
        return ret

    def _getPropertyByName(self, name):
        if self._aliases.has_key(name):
            return self._aliases[name]
        
        try:
            return self.ATTR_TABLE[name]
        except KeyError:
            raise UnknownProperty(name, self._current_option)

    def _setGroupProperties(self, property_names, group):
        if not property_names[0] in "-+":
            index = strpbrk(property_names, "-+")
            if index == -1:
                group.properties = self._getPropertyByName(property_names)
                return
            group.properties = self._getPropertyByName(property_names[:index])
            property_names = property_names[index:]

        while len(property_names) > 0:
            operator = property_names[0]
            property_names = property_names[1:]
            index = strpbrk(property_names, "-+")
            if index == -1:
                property_name = property_names
                property_names = ""
            else:
                property_name = property_names[:index]
                property_names = property_names[index:]
            if operator == "-":
                group.properties &= ~self._getPropertyByName(property_name)
            else:
                group.properties |= self._getPropertyByName(property_name)

    def _loadAliases(self, conf):
        for alias in conf.getSection(ALIASES).getOptions():
            self._aliases[alias.getName()] = self._getFileAttrs(alias.getValue())

    def _loadMonitoring(self, conf):
        for option in conf.getSection(MONITORING).getOptions():
            self._current_option = option
            group_name, property_names = option.getName(), option.getValue()

            add = True
            if group_name[0] == "!":
                group_name = group_name[1:]
                add = False
            
            recursive = True
            if group_name[0] == "=":
                group_name = group_name[1:]
                recursive = False

            group = Input.new_file_group(group_name, recursive)
            if add:
                if property_names:
                    self._setGroupProperties(property_names, group)
                for file in group.expand():
                    self._files[file.filename] = file
            else:
                for file in group.expand():
                    del self._files[file.filename]
    
    def _load(self):
        conf = MyConfigParser.ConfigParser(self._filename)
        conf.load()
        self._loadAliases(conf)
        self._loadMonitoring(conf)
        

if __name__ == "__main__":
    conf = Conf()
    print conf