sfatables/xmlrule.py

   1 import libxml2
   2 import libxslt
   3 from sfatables.globals import *
   4
   5 class XMLRule:
   6     rule_number = None
   7     chain = None
   8     xmldoc = None
   9     terminal = 0
  10     final_processor = '__sfatables_wrap_up__.xsl'
  11
  12     arguments = {'match':None,'target':None}
  13     processors = {'match':None,'target':None}
  14     context = {'match':None,'target':None}
  15
  16     def apply_processor(self, type, doc, output_xpath_filter=None):
  17         processor = self.processors[type]
  18
  19         # XXX TO CLEAN UP
  20         filepath = os.path.join(sfatables_config, 'processors', processor)
  21         # XXX
  22
  23         styledoc = libxml2.parseFile(filepath)
  24         style = libxslt.parseStylesheetDoc(styledoc)
  25         result = style.applyStylesheet(doc, None)
  26         if (output_xpath_filter):
  27             p = result.xpathNewContext()
  28             xpath_result = p.xpathEval(output_xpath_filter)
  29             if (xpath_result == []):
  30                 raise Exception("Could not apply processor %s."%processor)
  31
  32             stylesheet_result = xpath_result
  33             p.xpathFreeContext()
  34         else:
  35             stylesheet_result = result #style.saveResultToString(result)
  36
  37         style.freeStylesheet()
  38         #doc.freeDoc()
  39         #result.freeDoc()
  40
  41         return stylesheet_result
  42
  43     def wrap_up(self, doc):
  44         filepath = os.path.join(sfatables_config, 'processors', self.final_processor)
  45
  46         if not os.path.exists(filepath):
  47             # TODO: final_processor is not there yet
  48             return doc#rspec
  49
  50         styledoc = libxml2.parseFile(filepath)
  51         style = libxslt.parseStylesheetDoc(styledoc)
  52         #doc = libxml2.parseDoc(rspec)
  53         result = style.applyStylesheet(doc, None)
  54         stylesheet_result = result #style.saveResultToString(result)
  55         style.freeStylesheet()
  56         #doc.freeDoc()
  57         #result.freeDoc()
  58
  59         return stylesheet_result
  60
  61     def match(self, rspec):
  62         match_result = self.apply_processor('match',rspec,"//result/@verdict")
  63         return (match_result[0].content=='True')
  64
  65     def target(self, rspec):
  66         target_result = self.apply_processor('target',rspec,None)
  67         return target_result
  68
  69     def apply_interpreted(self, rspec):
  70         # Interpreted
  71         #
  72         # output =
  73         #    if (match(match_args, rspec)
  74         #       then target(target_args, rspec)
  75         #       else rspec
  76
  77         if (self.match(rspec)):
  78             return self.target(rspec)
  79         else:
  80             return rspec
  81
  82
  83     def apply_compiled(rspec):
  84         # Not supported yet
  85         return None
  86
  87     def load_xml_extension (self, type, chain, rule_number):
  88         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
  89
  90         self.xmldoc = libxml2.parseFile(filename)
  91         p = self.xmldoc.xpathNewContext()
  92
  93         context = p.xpathEval('//context/@select')
  94         self.context[type] = context[0].content
  95
  96         processor = p.xpathEval('//processor/@filename')
  97
  98         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
  99         if (context != []):
 100             self.terminal = 1
 101
 102         self.processors[type] = processor[0].content
 103         self.arguments[type] = p.xpathEval('//rule')
 104
 105         p.xpathFreeContext()
 106
 107
 108     def wrap_rspec (self, type, rspec):
 109         argument = self.arguments[type]
 110         p = rspec.xmldoc.xpathNewContext()
 111         root_node = p.xpathEval('/RSpec')
 112         if (not root_node or not root_node):
 113             raise Exception('An evil aggregate manager sent me a malformed RSpec. Please see the stack trace to identify it.')
 114
 115         root_node.addChild(arguments[type])
 116         return rspec
 117
 118     def __init__(self, chain=None, rule_number=None):
 119         if (chain and rule_number):
 120             self.load_xml_extension('match', chain, rule_number)
 121             self.load_xml_extension('target',chain, rule_number)
 122             self.rule_number = rule_number
 123             self.chain = chain
 124         return
 125
 126     def free(self):
 127         self.xmldoc.freeDoc()