sfatables/xmlrule.py

   1 import libxml2
   2 import libxslt
   3 from sfatables.globals import *
   4
   5 class XMLRule:
   6     def apply_processor(self, type, doc, output_xpath_filter=None):
   7         processor = self.processors[type]
   8
   9         # XXX TO CLEAN UP
  10         filepath = os.path.join(sfatables_config, 'processors', processor)
  11         # XXX
  12
  13         styledoc = libxml2.parseFile(filepath)
  14         style = libxslt.parseStylesheetDoc(styledoc)
  15         result = style.applyStylesheet(doc, None)
  16         if (output_xpath_filter):
  17             p = result.xpathNewContext()
  18             xpath_result = p.xpathEval(output_xpath_filter)
  19             if (xpath_result == []):
  20                 raise Exception("Could not apply processor %s."%processor)
  21
  22             stylesheet_result = xpath_result
  23             p.xpathFreeContext()
  24         else:
  25             stylesheet_result = result #style.saveResultToString(result)
  26
  27         style.freeStylesheet()
  28         #doc.freeDoc()
  29         #result.freeDoc()
  30
  31         return stylesheet_result
  32
  33     def wrap_up(self, doc):
  34         filepath = os.path.join(sfatables_config, 'processors', self.final_processor)
  35
  36         if not os.path.exists(filepath):
  37             raise Exception('Could not find final rule filter')
  38
  39         styledoc = libxml2.parseFile(filepath)
  40         style = libxslt.parseStylesheetDoc(styledoc)
  41         result = style.applyStylesheet(doc, None)
  42         stylesheet_result = result#style.saveResultToString(result)
  43         style.freeStylesheet()
  44         #doc.freeDoc()
  45         #result.freeDoc()
  46
  47         return stylesheet_result
  48
  49     def match(self, rspec):
  50         match_result = self.apply_processor('match',rspec,"//result/@verdict")
  51         return (match_result[0].content=='True')
  52
  53     def target(self, rspec):
  54         target_result = self.apply_processor('target',rspec,None)
  55         return target_result
  56
  57     def add_rule_context_to_rspec(self, doc):
  58         p = doc.xpathNewContext()
  59         context = p.xpathEval("//RSpec")
  60         if (not context):
  61             raise Exception('Request is not an rspec')
  62         else:
  63             # Add the request context
  64             matchNode = libxml2.newNode('match-context')
  65             for match_argument in self.arguments['match']:
  66                 matchNode.addChild(match_argument)
  67
  68             targetNode = libxml2.newNode('target-context')
  69             for target_argument in self.arguments['target']:
  70                 targetNode.addChild(target_argument)
  71
  72             context[0].addChild(matchNode)
  73             context[0].addChild(targetNode)
  74         p.xpathFreeContext()
  75
  76         return doc
  77
  78     def apply_interpreted(self, rspec):
  79         rspec = self.add_rule_context_to_rspec(rspec)
  80         # Interpreted
  81         #
  82         # output =
  83         #    if (match(match_args, rspec)
  84         #       then target(target_args, rspec)
  85         #       else rspec
  86
  87         if (self.match(rspec)):
  88             return self.wrap_up(self.target(rspec))
  89         else:
  90             return self.wrap_up(rspec)
  91
  92
  93     def apply_compiled(rspec):
  94         # Not supported yet
  95         return None
  96
  97     def load_xml_extension (self, type, chain, rule_number):
  98         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
  99
 100         self.xmldoc = libxml2.parseFile(filename)
 101         p = self.xmldoc.xpathNewContext()
 102
 103         context = p.xpathEval('//context/@select')
 104         self.context[type] = context[0].content
 105
 106         processor = p.xpathEval('//processor/@filename')
 107
 108         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
 109         if (context != []):
 110             self.terminal = 1
 111
 112         self.processors[type] = processor[0].content
 113         self.arguments[type] = p.xpathEval('//rule//argument[value!=""]')
 114
 115         p.xpathFreeContext()
 116
 117
 118     def __init__(self, chain=None, rule_number=None):
 119         self.rule_number = None
 120         self.chain = None
 121         self.xmldoc = None
 122         self.terminal = 0
 123         self.final_processor = '__sfatables_rule_wrap_up__.xsl'
 124
 125         self.arguments = {'match':None,'target':None}
 126         self.processors = {'match':None,'target':None}
 127         self.context = {'match':None,'target':None}
 128
 129         if (chain and rule_number):
 130             self.load_xml_extension('match', chain, rule_number)
 131             self.load_xml_extension('target',chain, rule_number)
 132             self.rule_number = rule_number
 133             self.chain = chain
 134         return
 135
 136     def free(self):
 137         self.xmldoc.freeDoc()